HK1151790B

HK1151790B - Hydrocyanation of pentenenitriles

Info

Publication number: HK1151790B
Application number: HK11105850.5A
Authority: HK
Inventors: 托马斯‧福; 詹姆斯‧迈克尔‧加德纳; 罗恩‧奥泽; 保罗‧S‧皮尔曼
Original assignee: 因温斯特技术公司
Priority date: 2008-01-15
Filing date: 2009-01-14
Publication date: 2014-02-14

Description

Hydrocyanation of pentenenitriles

Cross reference to related applications

This application claims benefit of filing date of U.S. provisional application No. 61/021,225 filed on 15/1/2008, which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates to an integrated process for the hydrocyanation of ethylenically unsaturated nitriles having 5 carbon atoms to produce Adiponitrile (ADN) and other dinitriles and for refining reaction product mixtures. More specifically, the present invention relates to a continuous process for hydrocyanating 3-pentenenitrile (3PN) and/or 4-pentenenitrile (4PN) and optionally 2-pentenenitrile (2PN) and refining the reaction product mixture using a catalyst composition comprising zero-valent nickel and at least one bidentate phosphorus-containing ligand in the presence of at least one lewis acid promoter.

Background

Hydrocyanation catalyst systems, in particular hydrocyanation catalyst systems associated with the hydrocyanation of ethylenically unsaturated compounds, have been described. For example, systems useful for hydrocyanation of 1, 3-Butadiene (BD) to form Pentenenitrile (PN) isomers and subsequent hydrocyanation of pentenenitrile to form Adiponitrile (ADN) are known in the commercially important nylon synthesis art. ADN is of particular interest because it is a commercially versatile and important intermediate in the industrial production of nylon polyamides that can be used to form films, fibers and molded articles.

CH₂＝CHCH＝CH₂+HCN→CH₃CH＝CHCH₂CN+CH₂＝CHCH₂CH₂CN (1)

1, 3-butadiene pentenenitrile

CH₃CH＝CHCH₂CN+CH₂＝CHCH₂CH₂CN+HCN→

NCCH₂CH₂CH₂CH₂CN (2)

Adiponitrile

In the prior art, hydrocyanation of ethylenically unsaturated compounds using transition metal complexes with monodentate phosphite ligands is discussed. See, e.g., U.S. Pat. nos. 3,496,215; 3,631,191, respectively; 3,655,723; and 3,766,237, and Advances in catalysis by Tolman et al, 1985, 33, 1. Improvements in zero-valent nickel-catalyzed hydrocyanation of ethylenically unsaturated compounds using certain multidentate phosphite ligands are also disclosed. Such improvements are described, for example, in U.S. Pat. nos. 5,821,378; 5,981,772; 6,020,516, respectively; and 6,284,865.

Hydrocyanation of activated ethylenically unsaturated compounds, such as conjugated ethylenically unsaturated compounds (e.g., BD and styrene) and strained ethylenically unsaturated compounds (e.g., norbornene) proceeds at useful rates without the use of lewis acid promoters. However, hydrocyanation of non-activated ethylenically unsaturated compounds such as 1-octene and 3PN requires the use of lewis acid promoters to obtain useful rates and yields for the production of linear nitriles such as n-octanonitrile and ADN, respectively.

The use of a promoter in hydrocyanation reactions is disclosed, for example, in U.S. Pat. No. 3,496,217. This patent discloses the use of a promoter selected from a large number of metal cation compounds having multiple counterions as a nickel catalyst promoter to improve hydrocyanation. U.S. patent No. 3,496,218 discloses a nickel hydrocyanation catalyst promoted with various boron containing compounds, including triphenylboron and alkali metal borohydride. U.S. patent No. 4,774,353 discloses a process for preparing dinitriles, including AND, from unsaturated nitriles, including pentenenitriles, in the presence of a zero-valent nickel catalyst AND a triorganotin promoter. Furthermore, U.S. patent No. 4,874,884 discloses a process for the production of ADN by the zero-valent nickel-catalyzed hydrocyanation of pentenenitriles in the presence of a synergistic combination of promoters selected according to the desired reaction kinetics of ADN synthesis. Also, the hydrocyanation of pentenenitrile to produce ADN using zero-valent nickel catalysts with multidentate phosphite ligands using Lewis acids is disclosed. See, for example, U.S. Pat. nos. 5,512,696; 5,723,641; 5,959,135; 6,127,567; and 6,646,148.

In the prior art, it is reported that some isomerization of 3PN to cis-and trans-2 PN may occur with hydrocyanation of 3PN and 4PN to produce ADN. However, in the use of nickel catalysts derived from monodentate phosphite ligands, such as Ni [ P (OC)₆H₅)₃]₄In hydrocyanation of 3PN and 4PN, U.S. patent No. 3,564,040 recognizes that the presence of 2PN is detrimental to catalyst efficiency even at low concentrations, and that the production of 2PN is undesirable because they constitute a yield loss and a poison for the catalyst.

To address this problem, U.S. Pat. No. 3,564,040 describes a method of maintaining the steady-state concentration of 2PN below 5 mole%, based on the nitrile present in the reaction mixture. Because trans-2 PN is difficult to separate from a mixture of 3PN and 4PN by distillation due to its close relative volatility, the disclosed process comprises: the trans-2 PN is catalytically isomerized to cis-2 PN, followed by removing the more volatile cis-2 PN isomers by fractional distillation of the mixture of pentenenitrile isomers. As described in U.S. Pat. nos. 3,496,217 and 3,496,218, the catalyst systems used for the isomerization of trans-2 PN to cis-2 PN are those which are also used for the hydrocyanation of pentenenitriles to ADN, in particular nickel catalysts derived from monodentate phosphite ligands.

In U.S. Pat. Nos. 3,852,325 and 3,852,327, alternative catalyst systems for the isomerization of trans-2 PN to cis-2 PN are disclosed. The main advantage of the catalyst system described therein is the avoidance of a significant carbon-carbon double bond shift in pentenenitrile isomers, which leads to isomerization of trans-2 PN to cis-2 PN, while 3PN is no longer substantially isomerized to 2 PN. The catalyst described in U.S. Pat. No. 3,852,325 is of the formula R₃C-X compounds, such as triphenylmethyl bromide, wherein R is an aryl group having up to 18 carbon atoms, and-X is selected from the group consisting of-H, -Cl, -Br, -I, -SH, -B (C)₆H₅)₄、-PF₆、-AsF₆、-SbF₆and-BF₄And the catalyst system described in us patent 3,852,327 is a lewis acid/lewis base composition such as a combination of zinc chloride and triphenylphosphine.

A different method for removing 2PN from a mixture of pentenenitrile isomers containing 3PN and 4PN is disclosed in U.S. patent 3,865,865. 2PN and/or 2-methyl-2-butenenitrile (2M2BN) can be selectively separated from a mixture of pentenenitrile containing 3PN and 4PN isomers by contacting the mixture with an aqueous solution of a treating agent containing sulfite and bisulfite ions and ammonium or alkali metal cations to produce an aqueous phase containing bisulfite adducts of 2PN and/or 2M2BN and an organic phase containing 3PN and 4PN and substantially free of 2PN and 2M2 BN. The recovered organic phase can provide a feedstock for further hydrocyanation of pentenenitriles to produce ADN while substantially reducing the amount of undesirable by-product 2PN detrimental to catalyst efficiency.

U.S. Pat. No. 6,127,567 discloses nickel catalyst compositions derived from bidentate phosphite ligands, and processes for hydrocyanation of monoethylenically unsaturated compounds that are faster, more selective, more efficient, and more stable than existing processes that use nickel catalysts derived from monodentate phosphites. U.S. Pat. No. 5,688,986 discloses that at least one member of such catalysts is capable of hydrocyanating a conjugated olefin to a nitrile, such as 2 PN. The present invention provides a novel process for hydrocyanation of pentenenitriles to produce dinitriles, particularly ADN, using certain catalyst compositions described in U.S. patent 6,127,567, as well as other catalyst compositions. The invention also provides a novel process for refining a reaction product mixture to obtain, for example, a stream comprising adiponitrile, a stream comprising a catalyst composition, and a stream comprising ethylenically unsaturated nitriles. The process can overcome the deleterious effects of 2PN on catalyst efficiency and can greatly reduce or eliminate yield losses to 2PN in pentenenitrile hydrocyanation reactions. The process can also provide lower capital and operating costs for adiponitrile production processes by (1) avoiding the need to separate unreacted ethylenically unsaturated nitrile from the reaction product mixture prior to liquid-liquid extraction, (2) avoiding a dedicated distillation column for removing cis-2 PN from the ethylenically unsaturated nitrile, and (3) using a simple and economical process for cleaning compounds that cannot be converted to ADN in the production process.

Summary of The Invention

In a first aspect, the present invention provides a hydrocyanation process for producing adiponitrile and other dinitriles having 6 carbon atoms which comprises:

a) forming a reaction mixture comprising an ethylenically unsaturated nitrile having 5 carbon atoms, hydrogen cyanide, and at least one catalyst composition in the presence of at least one lewis acid by continuously feeding the ethylenically unsaturated nitrile, hydrogen cyanide, and catalyst composition; wherein the catalyst composition comprises zero-valent nickel and at least one bidentate phosphorus-containing ligand; the bidentate phosphorus-containing ligand is selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, and a mixed phosphorus-containing ligand, or a combination of such members; and the bidentate phosphorus-containing ligand provides acceptable results according to at least one protocol of the 2-pentenenitrile hydrocyanation test method;

b) controlling X and Z such that the value of quotient Q is in the range of about 0.2 to about 10 by selecting a value for X in the range of about 0.001 to about 0.5 and a value for Z in the range of about 0.5 to about 0.99, wherein X is the total feed molar ratio of 2-pentenenitriles to all unsaturated nitriles and Z is the total feed molar ratio of hydrogen cyanide to all unsaturated nitriles, and wherein

Wherein 3PN is 3-pentenenitrile and 4PN is 4-pentenenitrile;

c) withdrawing a reaction product mixture comprising adiponitrile, 2-methylglutaronitrile, ethylenically unsaturated nitriles, the catalyst composition, and catalyst composition degradation products; and wherein the ratio of the concentration of 2-pentenenitrile to the concentration of 3-pentenenitrile in the reaction mixture is in the range of from about 0.2/1 to about 10/1;

d) extracting at least a portion of the reaction product mixture with an extractant selected from the group consisting of aliphatic hydrocarbons, cycloaliphatic hydrocarbons, and mixtures thereof, thereby obtaining an extract phase comprising the extractant and the catalyst composition and a raffinate phase comprising adiponitrile, 2-methylglutaronitrile, ethylenically unsaturated nitriles, catalyst composition degradation products, and the extractant; and

e) the extract phase is distilled to obtain a first stream comprising the extractant and a second stream comprising the catalyst composition.

Another aspect of the invention is a process further comprising distilling the raffinate phase to obtain a third stream comprising the extractant and a fourth stream comprising adiponitrile, 2-methylglutaronitrile, ethylenically unsaturated nitriles, and catalyst composition degradation products.

Another aspect of the invention is a process further comprising distilling the fourth stream to obtain a fifth stream comprising ethylenically unsaturated nitriles and a sixth stream comprising adiponitrile, 2-methylglutaronitrile and catalyst composition degradation products.

Another aspect of the invention is a process further comprising distilling the sixth stream to obtain a seventh stream comprising adiponitrile and 2-methylglutaronitrile and an eighth stream comprising catalyst degradation products.

Another aspect of the invention is a process further comprising distilling the seventh stream to obtain a ninth stream comprising 2-methylglutaronitrile and a tenth stream comprising adiponitrile.

Another aspect of the invention is a process further comprising returning at least a portion of the first stream, at least a portion of the third stream, or a combination thereof to an extraction.

Another aspect of the invention is the process wherein at least a portion of the fifth stream is returned to the reaction mixture.

Another aspect of the invention is a process wherein at least a portion of the second stream is combined with at least a portion of the fifth stream and optionally returned to the reaction mixture.

Another aspect of the invention is the process wherein the fifth stream further comprises compounds that cannot be converted to adiponitrile and wherein at least a portion of the fifth stream is withdrawn to purge at least a portion of the compounds that cannot be converted to adiponitrile.

Another aspect of the present invention is the process wherein in the fifth stream, the total content of compounds that cannot be converted to adiponitrile is greater than about 10% by weight.

Another aspect of the invention is a process further comprising distilling at least a portion of the fifth stream to obtain an eleventh stream comprising cis-2-pentenenitrile and a twelfth stream comprising 3-pentenenitrile.

Another aspect of the invention is the process wherein at least a portion of the twelfth stream is returned to the reaction mixture.

Another aspect of the invention is a process further comprising contacting at least a portion of the second stream with nickel chloride and a reducing metal that is more electropositive than nickel in the presence of a nitrile solvent to obtain a fifteenth stream, and optionally returning at least a portion of the fifteenth stream to the reaction mixture.

Another aspect of the present invention is a process further comprising contacting aqueous ammonia with at least one stream selected from the group consisting of a reaction product mixture, a raffinate phase, a fourth stream, a sixth stream, and combinations thereof, wherein the reaction product mixture, the raffinate phase, the fourth stream, the sixth stream, and combinations thereof further comprise at least one lewis acid.

Another aspect of the invention is a process wherein the distillation of the extract phase is carried out in two stages wherein the bottom temperature of each distillation column is about 150 ℃ or less.

Another aspect of the invention is a process wherein the distillation of the extract phase is carried out in two stages wherein the bottom temperature of each distillation column is about 120 ℃ or less.

Another aspect of the invention is the process wherein the catalyst composition further comprises at least one monodentate phosphite ligand.

Another aspect of the invention is the process wherein the bidentate phosphorus-containing ligand is a phosphite ligand selected from a member of the group represented by formula XXXIII and formula XXXIV:

formula XXXIII formula XXXIV

Wherein each R⁴¹Independently selected from the group consisting of: primary and secondary hydrocarbyl groups of 1 to 6 carbon atoms;

each R⁴⁵Independently selected from the group consisting of: methyl, ethyl and primary hydrocarbyl of 3 to 6 carbon atoms; and is

Each R⁴²，R⁴³，R⁴⁴，R⁴⁶，R⁴⁷And R⁴⁸Independently selected from the group consisting of: h, an aryl group, and a primary, secondary or tertiary hydrocarbyl group of 1 to 6 carbon atoms.

Another aspect of the invention is a process further comprising introducing a stream comprising a crude bidentate phosphite ligand mixture comprising phosphite ligands selected from members of the group represented by formula XXXIII and formula XXXIV:

formula XXXIII formula XXXIV

Another aspect of the invention is the process wherein the at least one lewis acid comprises zinc chloride and the extractant comprises cyclohexane.

Another aspect of the invention is a method wherein at least a portion of the second stream is introduced into a 3-pentenenitrile production process comprising 1, 3-butadiene hydrocyanation, 2-methyl-3-butenenitrile isomerization, or a combination thereof.

Detailed description of the drawings

FIG. 1 schematically illustrates one embodiment of the process of the present invention.

FIG. 2 schematically illustrates another embodiment of the process of the present invention.

Fig. 3 schematically illustrates an embodiment of the process of the invention, wherein the second stream is contacted with nickel chloride and a reducing metal that is more electropositive than nickel, thereby obtaining a fifteenth stream that may be returned to the reaction mixture.

Figure 4 schematically illustrates an embodiment of the process of the invention wherein the fourth stream is contacted with aqueous ammonia.

Detailed Description

As used herein, the terms "2 PN", "2-pentenenitrile" and "2-pentenenitrile" include cis-2-pentenenitrile (cis-2 PN) and trans-2-pentenenitrile (trans-2 PN), unless otherwise specified. Similarly, the terms "3 PN", "3-pentenenitrile" and "3-pentenenitrile" include cis-3-pentenenitrile (cis-3 PN) and trans-3-pentenenitrile (trans-3 PN), unless otherwise specified. The term "4 PN" refers to 4-pentenenitrile. The term "2M 3 BN" refers to 2-methyl-3-butenenitrile. The term "2M 2 BN" refers to 2-methyl-2-butenenitrile and includes both (Z) -2-methyl-2-butenenitrile [ (Z) -2M2BN ] and (E) -2-methyl-2-butenenitrile [ (E) -2M2BN ], unless otherwise specified.

As used herein, the terms "ethylenically unsaturated nitrile having 5 carbon atoms" and "ethylenically unsaturated nitrile" mean pentenenitrile and methylbutenenitrile and include, alone or in combination, 2PN, 3PN, 4PN, 2M3BN, and 2M2 BN. As used herein, the term "unsaturated nitrile" also means pentenenitrile and methylbutenenitrile.

As used herein, the term "ADN" refers to adiponitrile. The term "MGN" refers to 2-methylglutaronitrile.

Distillation "bottom temperature" refers to the temperature of the bottom material in the distillation apparatus, e.g., the temperature that is circulated through a heat exchanger.

The present invention provides a process for hydrocyanating an ethylenically unsaturated nitrile having 5 carbon atoms to produce adiponitrile and other nitriles having 6 carbon atoms and for refining the reaction product mixture. A reaction mixture comprising an ethylenically unsaturated nitrile having 5 carbon atoms, hydrogen cyanide, and at least one catalyst composition is formed by continuously feeding these materials in the presence of at least one lewis acid. A reaction product mixture comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition, and catalyst composition degradation products wherein the ratio of 2PN concentration to 3PN concentration in the reaction mixture is in the range of about 0.2/1 to about 10/1 is withdrawn from the reaction zone.

In the case where the reaction product mixture is suitable for catalyst composition recovery by liquid-liquid extraction by contact with an extractant, i.e. if phase separation occurs during extraction, at least a portion of the reaction product mixture is extracted to obtain an extract phase and a raffinate phase. The extract and raffinate phases are then refined in a series of distillations to provide, for example, refined ADN, ethylenically unsaturated nitrile, catalyst composition degradation product, and extractant.

For example, an extract phase comprising the extractant and the catalyst composition is distilled to obtain a first stream comprising the extractant and a second stream comprising the catalyst composition. The extract phase may, for example, be subjected to a two-stage distillation wherein the temperature at the bottom of each distillation column is about 150 ℃ or less, for example about 120 ℃ or less.

Optionally, to increase the concentration of nickel in the catalyst composition to a desired level, at least a portion of the second stream is contacted with nickel chloride in the presence of a reducing metal that is more electropositive than nickel to obtain a fifteenth stream. Optionally, at least a portion of the fifteenth stream is returned to the reaction mixture as at least a portion of the catalyst composition is fed.

Optionally, at least a portion of the second stream is introduced into a 3PN production process comprising 1, 3-butadiene hydrocyanation, 2-methyl-3-butenenitrile isomerization, or a combination thereof.

The raffinate phase is distilled to obtain a third stream comprising the extractant and a fourth stream comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products. Distilling the fourth stream to obtain a fifth stream comprising ethylenically unsaturated nitriles and a sixth stream comprising ADN, MGN, and catalyst composition degradation products. Distilling the sixth stream to obtain a seventh stream comprising ADN and MGN and an eighth stream comprising catalyst composition degradation products. Distilling the seventh stream to obtain a ninth stream comprising MGN and a tenth stream comprising ADN.

Optionally, at least a portion of the first stream and at least a portion of the third stream, or a combination thereof, may be returned to the extraction step.

Optionally, at least a portion of the fifth stream is returned to the reaction mixture. Optionally, at least a portion of the fifth stream may be mixed with the second stream, and this combined stream may be returned to the reaction mixture. Optionally, at least a portion of the fifth stream is mixed with the second stream before or after contacting the second stream with nickel chloride in the presence of a reducing metal that is more electropositive than nickel to obtain a fifteenth stream.

The fifth stream may also comprise compounds that cannot be converted to ADN, and at least a portion of the fifth stream may be withdrawn to purge at least a portion of compounds that cannot be converted to ADN by the production process. For example, the total content of the fifth stream of compounds that cannot be converted to ADN may exceed about 10 wt.%.

Optionally, distilling the fifth stream to obtain an eleventh stream comprising cis-2 PN and a twelfth stream comprising 3 PN. At least a portion of the twelfth stream can be returned to the reaction mixture. At least a portion of the eleventh stream may be withdrawn and purged by removing compounds that cannot be converted to ADN.

In one embodiment of the process of the present invention, the at least one lewis acid comprises zinc chloride and the extractant comprises cyclohexane.

In situations where a reaction product mixture comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition, and catalyst composition degradation products, wherein the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture is in the range of about 0.2/1 to about 10/1, is not suitable for catalyst composition recovery by liquid-liquid extraction through contact with an extractant, the amount of ethylenically unsaturated nitrile in the reaction product mixture should be adjusted so that phase separation occurs during extraction. In this case, for example, the reaction product mixture may be distilled prior to extraction to obtain a thirteenth stream comprising ethylenically unsaturated nitriles and a fourteenth stream devoid of ethylenically unsaturated nitriles and comprising the catalyst composition, catalyst degradation products ADN, MGN, and ethylenically unsaturated nitriles. The fourteenth stream is extracted to obtain an extract phase and a raffinate phase, and these phases are subsequently refined, for example in a series of distillations, as described above, to obtain, for example, refined ADN, the catalyst composition, the ethylenically unsaturated nitrile, and the extractant. Optionally, at least a portion of the thirteenth stream may be returned to the reaction mixture as part of the ethylenically unsaturated nitrile feed. In one embodiment of the process of the present invention, the at least one lewis acid comprises zinc chloride and the extractant comprises cyclohexane.

Regardless of whether the reaction product mixture has characteristics suitable for phase separation in extraction, the stream containing the lewis acid may be contacted with aqueous ammonia to at least partially separate the lewis acid, such as zinc chloride, from the other components of the stream. The lewis acid-containing stream includes, for example, a reaction product mixture, a raffinate phase, a fourth stream, a sixth stream, a fourteenth stream, and combinations thereof.

By using an appropriate catalyst composition in the hydrocyanation of ethylenically unsaturated nitriles having 5 carbon atoms to produce ADN and other nitriles having 6 carbon atoms, the yield loss due to the simultaneous production of 2PN from 3PN can be greatly reduced or eliminated by controlling the ratio of 2PN concentration to 3PN concentration in the reaction mixture from about 0.2/1 to about 10/1.

Control of the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture can be achieved by controlling X, the overall feed molar ratio of 2PN to all unsaturated nitriles, and controlling Z, the overall feed molar ratio of Hydrogen Cyanide (HCN) to all unsaturated nitriles. X and Z may be controlled by selecting a value for X in the range of about 0.001 to about 0.5 and by selecting a value for Z in the range of about 0.5 to about 0.99, such that the quotient Q has a value in the range of about 0.2 to about 10, wherein:

wherein 3PN is 3-pentenenitrile and 4PN is 4-pentenenitrile. When the ratio of the 2PN concentration to the 3PN concentration in the reaction mixture is controlled to be from about 1/1 to about 5/1, X and Z can be controlled, for example, by selecting the value of X in the range of from about 0.01 to about 0.25 and by selecting the value of Z in the range of from about 0.70 to about 0.99, such that the quotient Q is in the range of from about 1 to about 5.

Advantageously, a zero-valent nickel catalyst system and much less (far less) process equipment can be used to convert 2PN to valuable products 3PN, 4PN, and ADN. The prior art drawbacks of maintaining a steady-state concentration of 2PN below 5 mole percent (based on the nitrile present in the reaction mixture) can be overcome by using an appropriate catalyst composition that can be expected to be faster, more selective, more efficient, and more stable than prior art catalyst compositions derived from monodentate phosphite ligands used in the hydrocyanation of ethylenically unsaturated compounds. Using an appropriate catalyst composition, 2PN can be converted to useful products, such as 3PN and 4PN, and not a yield loss. Furthermore, because control of the overall feed molar ratio of 2PN to all unsaturated nitriles can be achieved by recycling the ethylenically unsaturated nitriles containing 2PN directly from the reaction product mixture in the process or by adding the 2PN produced to a separate process, no distillation column dedicated to the removal of cis-2 PN is required to be able to reduce 2PN in the hydrocyanation reaction. This can save investment and running costs, and simplify the process.

Ethylenically unsaturated nitriles having 5 carbon atoms can be prepared by reacting Hydrogen Cyanide (HCN) with 1, 3-Butadiene (BD).

CH₂＝CHCH＝CH₂+HCN→

1, 3-butadiene

CH₃CH＝CHCH₂CN+CH₂＝CHCH(CH₃)CN (3)

Trans-and cis-2-methyl-3-

3-pentenenitrile butenenitrile

The predominantly linear pentenenitrile product formed by hydrocyanation of BD is trans-3 PN using a transition metal complex with a monodentate phosphite (e.g., U.S. Pat. Nos. 3,496,215; 3,631,191; 3,655,723; and 3,766,237) and a zero-valent nickel catalyst with a multidentate phosphite ligand (e.g., U.S. Pat. Nos. 5,821,378; 5,981,772; 6,020,516; and 6,284,865). As described in the prior art, the branched BD hydrocyanation product 2-methyl-3-butenenitrile (2M3BN) may be isomerized to predominantly trans-3 PN using the same catalyst composition used for BD hydrocyanation. See, for example, U.S. Pat. nos. 3,536,748 and 3,676,481. The main product trans-3 PN from hydrocyanation of BD and isomerization of 2M3BN may also contain minor amounts of 4PN, cis-3 PN, 2PN, and 2M2BN isomers.

Trans-3 PN&Cis-3 PN

CH₂＝CHCH₂CH₂CN+CH₃CH₂CH＝CHCN+ CH₃CH＝C(CH₃)CN (4)

4PN trans-2 PN & cis-2 PN (E) -2M2BN & (Z) -2M2BN

As described in the prior art, 2PN useful in the present invention can be prepared in greater quantities from the concurrent isomerization of 3PN to 2PN during the hydrocyanation of 3PN and/or 4PN to form ADN and other dinitriles. The isolated 2PN source used in the present invention may be provided by separating the cis-2 PN isomers by fractional distillation of a mixture of pentenenitrile isomers, as disclosed in the art. See, for example, U.S. patent No. 3,852,327. Alternatively, it is not necessary to separate cis-2 PN from a mixture of pentenenitrile isomers. The 2PN mixture containing 2PN, 3PN and 4PN can be separated from the pentenenitrile hydrocyanation reaction product comprising unreacted pentenenitrile, ADN and other 6 carbon dinitriles, catalyst and promoter by methods known in the art, for example, by vacuum distillation. The 2PN mixture may then be recycled directly to the pentenenitrile hydrocyanation process as a side stream or overhead make of a distillation column. Alternatively, the hydrocyanation reaction process of the present invention may be operated at a sufficiently high conversion of pentenenitriles to enable direct feeding of the hydrocyanation reaction products comprising unreacted ethylenically unsaturated nitriles, ADN and other 6 carbon dinitriles, a catalyst composition and a lewis acid promoter, wherein the molar ratio of pentenenitriles to dinitriles is from about 0.65 to about 2.5, to a liquid-liquid extraction process as described, for example, in U.S. patent No. 6,936,171. Pentenenitrile mixtures containing 2PN, 3PN and 4PN, such as recovered by distillation of the extract, raffinate or extract and raffinate phases of these liquid-liquid extraction processes, may also be recycled to the pentenenitrile hydrocyanation process of the present invention, for example as part of an ethylenically unsaturated nitrile feed.

Performing a hydrocyanation process in the presence of at least one lewis acid and using a catalyst composition comprising zero-valent nickel and at least one monodentate phosphorus-containing (P-containing) ligand selected from the group consisting of: phosphites, phosphonites, phosphinites, phosphines, and mixed phosphorus-containing ligands or combinations of these members. As used herein, the term "mixed phosphorus-containing ligand" means a multidentate phosphorus-containing ligand comprising at least one combination selected from the group consisting of: phosphite-phosphonite, phosphite-phosphinite, phosphite-phosphine, phosphonite-phosphinite, phosphonite-phosphine, and phosphinite-phosphine or combinations of these members.

The catalyst composition may also comprise at least one lewis acid promoter.

The catalyst composition may comprise at least one monodentate P-containing ligand selected from the group consisting of: phosphites, phosphonites, phosphinites, and phosphines or combinations of these members, provided that the monodentate P-containing ligand does not detract from the beneficial aspects of the invention. The monodentate P-containing ligand can be present as an impurity from the synthesis of the P-containing ligand, or the monodentate P-containing ligand can be added as a single or additional component of the catalyst. The monodentate P-containing ligand can be a mixture of P-containing ligands.

As used herein, the term "catalyst composition" also includes within its meaning a catalyst precursor composition, indicating that at some point zero valent nickel is bound to at least one P-containing ligand and that, most likely, additional reactions occur during hydrocyanation, such as, for example, complexation of the starting catalyst composition with an ethylenically unsaturated compound. As used herein, the term "catalyst composition" also comprises in its meaning recycled catalyst, i.e. catalyst composition comprising zero-valent nickel and at least one P-containing ligand, which has been used in the process of the present invention, which is returned or can be returned to the process and reused.

Partial degradation of the catalyst composition may occur during hydrocyanation and subsequent refining, as disclosed, for example, in U.S. Pat. No. 3,773,809, incorporated herein by reference. Catalyst composition degradation products are disclosed, for example, in U.S. Pat. No. 3,773,809, which is incorporated herein by reference. The resulting degradation products may include oxidized nickel compounds such as species comprising nickel (II) cyanide. Additional degradation products may include, for example, hydrolyzed phosphorus compounds from the reaction of the P-containing ligand with trace amounts of water that may be present in the feedstock (e.g., in HCN). The catalyst composition degradation products may also include oxidized phosphorus compounds having a phosphorus atom with an oxidation valence state (V) resulting from the reaction of the P-containing ligand with oxygen or with a peroxide. The oxygen or peroxide may be present in the feedstock, for example in the ethylenically unsaturated nitrile, for example as a result of leakage in the equipment, or by dissolving the oxygen in the ethylenically unsaturated nitrile, for example in storage, which subsequently forms the peroxide. Additional catalyst composition degradation products may include monodentate phosphorus-containing compounds, for example, resulting from thermally induced, or proton or base catalyzed rearrangement of groups on the phosphorus atom of the P-containing ligand. As used herein, the term "catalyst composition degradation products" is intended to include the various types of degradation products described herein and includes at least one compound selected from the group consisting of oxidized nickel compounds, hydrolyzed P-containing ligand compounds, oxidized P-containing ligand compounds, and combinations thereof.

The term "hydrocarbyl" is well known in the art and refers to a hydrocarbon molecule from which at least one hydrogen atom has been removed. Such molecules may contain single, double or triple bonds.

The term "aryl" is well known in the art and refers to an aromatic hydrocarbon molecule from which at least one hydrogen atom has been removed. Examples of suitable aryl groups include, for example, those containing from 6 to 10 carbon atoms, which may be unsubstituted, mono-or polysubstituted. Suitable substituents include, for example, C₁To C₄Hydrocarbyl, or halogen such as fluorine, chlorine or bromine, or halohydrocarbyl such as trifluoromethyl, or aryl such as phenyl.

The P-containing ligands of the Ni (0) complexes and the free P-containing ligands may be monodentate or multidentate, for example bidentate or tridentate. The term "bidentate" is well known in the art and means that two phosphorus atoms of a ligand are bound to a single metal atom. The term "tridentate" means that the three phosphorus atoms on the ligand are bound to a single metal atom. The P-containing ligand may be a single compound or a mixture of compounds. The P-containing ligand may be selected from the group consisting of: phosphites, phosphonites, phosphinites, phosphines, and mixed P-containing ligands or combinations of these members. The multidentate P-containing ligand can be represented by formula I:

formula I

Wherein

X¹¹，X¹²，X¹³，X²²，X²²，X²³Independently represents oxygen or a single bond,

R¹¹，R¹²independently represent identical or different, single or bridged organic radicals,

R²¹，R²²independently represent identical or different, single or bridged organic radicals, and

y represents a bridging group.

It is to be understood that formula I may represent a single compound or a mixture of different compounds having the indicated formula.

In one embodiment, the group X¹¹，X¹²，X¹³，X²¹，X²²，X²³All may represent oxygen. In such a case, the bridging group Y is linked to the phosphite group. In such a case, the multidentate P-containing ligand represented by formula I is a phosphite.

In another embodiment, X¹¹And X¹²May each represent oxygen, and X¹³Represents a single bond; or X¹¹And X¹³May each represent oxygen, and X¹²Represents a single bond such that X is¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphonite. In such a case, X²¹，X²²And X²³Can each represent oxygen such that X²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphite; or X²¹And X²²Can respectively represent oxygen and X²³Represents a single bond; or X²¹And X²³Can respectively represent oxygen and X²²Represents a single bond such that X is²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of a phosphonite; or X²³May represent oxygen and X²¹And X²²Each represents a single bond; or X²¹May represent oxygen and X²²And X²³Each represents a single bond, such that X is²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of a phosphinite; or X²¹，X²²And X²³May each represent a single bond, such that X is²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphine.

When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphonite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphite, the monodentate ligand represented by formula I is a phosphite-phosphonite and is an example of a mixed P-containing ligand. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphonite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphonite, the multidentate P-containing ligand represented by formula I is a phosphonite. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphonite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphinite, the multidentate P-containing ligand represented by formula I is a phosphonite-phosphinite and is an example of a mixed P-containing ligand. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphonite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphine, the multidentate P-containing ligand represented by formula I is a phosphonite-phosphine, and is an example of a mixed P-containing ligand.

In another embodiment, X¹³Can represent oxygen and X¹¹And X¹²Each represents a single bond; or X¹¹May represent oxygen and X¹²And X¹³Each represents a single bond, such that¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of the phosphinite. In such a case, X²¹，X²²And X²³Can each represent oxygen such that X²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphite; or X²³May represent oxygen and X²¹And X²²Each represents a single bond; or X²¹May represent oxygen and X²²And X²³Each represents a single bond, such that²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of a phosphinite; or X²¹，X²²And X²³May each represent a single bond, such that X is²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphine.

When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphinite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphite, the multidentate P-containing ligand represented by formula I is a phosphite-phosphinite and is an example of a mixed P-containing ligand. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphinite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphinite, the multidentate P-containing ligand represented by formula I is a phosphinite. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of a phosphinite and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphine, the multidentate P-containing ligand represented by formula I is a phosphinite-phosphine and is an example of a mixed P-containing ligand.

In another embodiment, X¹¹，X¹²And X¹³May each represent a single bond, such that X is¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of the phosphine. In such a case, X²¹，X²²And X²³Can each represent oxygen such that X²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphite; or X²¹，X²²And X²³May each represent a single bond, such that X is²¹，X²²And X²³The surrounding phosphorus atom may be the central atom of the phosphine.

When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of the phosphine and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphite, the multidentate P-containing ligand represented by formula I is a phosphite-phosphine and is an example of a mixed P-containing ligand. When is composed of X¹¹，X¹²And X¹³The surrounding phosphorus atom is the central atom of the phosphine and is composed of X²¹，X²²And X²³Where the surrounding phosphorus atom is the central atom of a phosphine, the multidentate P-containing ligand represented by formula I is a phosphine.

The bridging group Y may be an aryl group substituted, for example, by: c₁-C₄A hydrocarbon group, or a halogen such as fluorine, chlorine, bromine or a halogenated hydrocarbon group such as trifluoromethyl, or an aryl group such as phenyl, or an unsubstituted aryl group, for example those having 6 to 20 carbon atoms in the aromatic system, for example 2, 2 '-biphenyl, 1, 1' -di-2-naphthyl, or pyrocatechol.

Radical R¹¹And R¹²May independently represent the same or different organic groups. R¹¹And R¹²May be an aryl group, such as those containing from 6 to 10 carbon atoms, which may be unsubstituted or mono-or polysubstituted, for example by: c₁-C₄A hydrocarbon group, or a halogen such as fluorine, chlorine or bromine or a halogenated hydrocarbon group such as trifluoromethyl, or an aryl group such as phenyl, or an unsubstituted aryl group.

Radical R²¹And R²²May independently represent the same or different organic groups. R²¹And R²²May be aryl, e.g. bagThose containing from 6 to 10 carbon atoms, which may be unsubstituted or mono-or polysubstituted, for example by: c₁-C₄A hydrocarbyl group, or a halogen such as fluorine, chlorine or bromine, or a halogenated hydrocarbyl group such as trifluoromethyl, or an aryl group such as phenyl, or an unsubstituted aryl group.

Radical R¹¹And R¹²May be unitary or bridged. Radical R²¹And R²²Or may be mono-or bridged. Radical R¹¹，R¹²，R²¹And R²²May both be unitary, or two may be bridged, two are unitary, or all four are bridged in the manner described.

The P-containing ligand can also be a polymeric ligand composition, as described, for example, in U.S. patent nos. 6,284,865; U.S. patent No. 6,924,345, or U.S. published patent application No. 2003/135014. Methods for preparing the polymeric ligand compositions are well known in the art and are disclosed, for example, in the above-cited references.

The catalyst may comprise at least one monodentate P-containing ligand selected from the group consisting of: phosphites, phosphonites, phosphinites, and phosphines or combinations of these members. When a multidentate P-containing ligand is used, the monodentate P-containing ligand may be added as an additional component of the catalyst, or it may be present, for example, as an impurity from the synthesis of the P-containing ligand, or the monodentate P-containing ligand may be used in the absence of the multidentate P-containing ligand. The monodentate P-containing ligand can be represented by formula II

P(X¹R³¹)(X²R³²)(X³R³³)

Formula II

Wherein

X¹，X²，X³Independently represents oxygen or a single bond, and

R³¹，R³²，R³³independently of each otherRepresent identical or different, single or bridged organic radicals.

It is to be understood that formula II may represent a single compound or a mixture of different compounds having the indicated formula.

In one embodiment, the group X¹，X²And X³All may represent oxygen, such that formula II represents formula P (OR)³¹)(OR³²)(OR³³) Phosphite of (1), wherein R³¹，R³²And R³³Have the meaning defined herein.

If the group X is¹，X²And X³One represents a single bond and two groups represent oxygen, formula II represents formula P (OR)³¹)(OR³²)(R³³)，P(R³¹)(OR³²)(OR³³) OR P (OR)³¹)(R³²)(OR³³) Phosphonite of (a), wherein R³¹，R³²And R³³Have the meaning defined herein.

If the group X is¹，X²And X³Two of which represent a single bond and one represents oxygen, formula II represents formula P (OR)³¹)(R³²)(R³³) Or P (R)³¹)(OR³²)(R³³) Or P (R)³¹)(R³²)(OR³³) Of phosphinite, where R³¹，R³²And R³³Have the meaning defined herein.

Group X¹，X²，X³May independently represent oxygen or a single bond. If the group X is¹，X²And X³All represent single bonds, formula II represents formula P (R)³¹)(R³²)(R³³) In which R is³¹，R³²And R³³Have the meaning defined herein.

Radical R³¹，R³²And R³³May independently represent the same or different organic groups, e.g. hydrocarbon groups containing 1 to 10 carbon atoms, such as AAn alkyl group, such as phenyl, o-tolyl, m-tolyl, p-tolyl, 1-naphthyl, or 2-naphthyl, or a hydrocarbyl group containing 1 to 20 carbon atoms, such as 1,1 '-biphenol or 1, 1' -binaphthol. R³¹，R³²And R³³The groups may be directly attached to each other, meaning not only through the central phosphorus atom. Alternatively, R³¹，R³²And R³³The groups may not be directly linked to each other.

For example, R³¹，R³²And R³³May be selected from the group consisting of: phenyl, o-tolyl, m-tolyl, and p-tolyl. As another example, R³¹，R³²And R³³Up to two of the groups may be phenyl. Alternatively, R³¹，R³²And R³³Up to two of the groups may be o-tolyl groups.

A compound of the formula IIa,

(O-tolyl-O-)_w(m-tolyl-O-)_x(p-tolyl-O-)_y(phenyl-O-)_zP

Formula IIa

Can be used as multidentate P-containing ligands, wherein w, x, y, and z are integers, and the following conditions apply: w + x + y + z is 3 and w, z is ≦ 2.

Examples of compounds of formula IIa include (p-tolyl-O-) (phenyl-O-)₂P, (m-tolyl-O-) (phenyl-O-)₂P, (O-tolyl-O-) (phenyl-O-)₂P (P-tolyl-O-)₂(phenyl-O-) P, (m-tolyl-O-)₂(phenyl-O-) P, (O-tolyl-O-)₂(phenyl-O-) P, (m-tolyl-O-) (P-tolyl-O-) (phenyl-O-) P, (O-tolyl-O-) (m-tolyl-O-) (phenyl-O-) P, (P-tolyl-O-)₃P, (m-tolyl-O-) (P-tolyl-O-)₂P, (O-tolyl-O-) (P-tolyl-O-)₂P, (m-tolyl-O-)₂(P-tolyl-O-) P, (O-tolyl-O-)₂(P-tolyl-O-) P, (O-tolyl-O-) (m-tolyl-O-) (P-tolyl-O-) P, (m-tolyl-O-)₃P, (O-tolyl-O-) (m-tolyl-O-)₂P, (O-tolyl-O-)₂(m-tolyl-O-) P, or a mixture of these compounds.

The (m-tolyl-O-) containing compound can be obtained, for example, by reacting a mixture containing m-cresol and p-cresol, specifically present in a molar ratio of 2: 1, as is present during the distillation of crude oil, with a phosphorus trihalide such as phosphorus trichloride₃P, (m-tolyl-O-)₂(P-tolyl-O-) P, (m-tolyl-O-) (P-tolyl-O-)₂P, and (P-tolyl-O-)₃A mixture of P.

Further examples of multidentate P-containing ligands are the phosphites disclosed in U.S. patent No. 6,770,770, and referred to herein as phosphites of formula IIb,

P(OR³¹)_x(OR³²)_y(OR³³)_z(OR³⁴)_p

formula IIb

Wherein

R³¹Is an aromatic group having C in the ortho position relative to the oxygen atom linking the phosphorus atom to the aromatic system₁-C₁₈An alkyl substituent or having an aromatic substituent in an ortho position relative to the oxygen atom linking the phosphorus atom to the aromatic system, or having an aromatic system fused in an ortho position relative to the oxygen atom linking the phosphorus atom to the aromatic system;

R³²is an aromatic group having C in the meta position relative to the oxygen atom linking the phosphorus atom to the aromatic system₁-C₁₈Alkyl substituents, or having aromatic substituents in the meta position relative to the oxygen atom linking the phosphorus atom to the aromatic systemAn aromatic system fused in the meta position to the oxygen atom of the aromatic system, wherein the aromatic group has a hydrogen atom in the ortho position relative to the oxygen atom connecting the phosphorus atom to the aromatic system;

R³³is an aromatic group having C at the para-position relative to the oxygen atom linking the phosphorus atom to the aromatic system₁-C₁₈An alkyl substituent or an aromatic substituent in a para position relative to the oxygen atom connecting the phosphorus atom to the aromatic system, wherein the aromatic group has a hydrogen atom in an ortho position relative to the oxygen atom connecting the phosphorus atom to the aromatic system;

R³⁴is an aryl group having a different meaning with respect to R in the ortho, meta and para positions relative to the oxygen atom linking the phosphorus atom to the aromatic system³¹，R³²And R³³Substituents of those defined wherein the aryl group has a hydrogen atom in the ortho position relative to the oxygen atom connecting the phosphorus atom to the aromatic system;

x is 1 or 2; and is

y, z, and p are independently 0, 1, or 2, provided that x + y + z + p is 3.

Radical R³¹Examples of (b) include o-tolyl, o-ethylphenyl, o-n-propylphenyl, o-isopropylphenyl, o-n-butylphenyl, o-sec-butylphenyl, o-tert-butylphenyl, (o-phenyl) phenyl, or 1-naphthyl.

Radical R³²Examples of (b) include m-tolyl, m-ethylphenyl, m-n-propylphenyl, m-isopropylphenyl, m-n-butylphenyl, m-sec-butylphenyl, m-tert-butylphenyl, (m-phenyl) -phenyl, or 2-naphthyl groups.

Radical R³³Examples of (b) include p-tolyl, p-ethylphenyl, p-n-propylphenyl, p-isopropylphenyl, p-n-butylphenyl, p-sec-butylphenyl, p-tert-butylphenyl, or (p-phenyl) phenyl.

Radical R³⁴It may for example be phenyl.

The subscripts x, y, z, and p in the compounds of formula IIb may have the following possibilities:

x	y	z	p
				1	0	0	2
1	0	1	1
				1	1	0	1
2	0	0	1
				1	0	2	0
1	1	1	0
				1	2	0	0
2	0	1	0
				2	1	0	0

examples of phosphites of the formula IIb are those wherein p is 0 and R is³¹，R³²And R³³Independently selected from the group consisting of o-isopropylphenyl, m-tolyl, and p-tolyl.

Further examples of phosphites of the formula IIb are those wherein R is³¹Is an o-isopropylphenyl radical, R³²Is a m-tolyl group, and R³³Is a p-tolyl group having the subscripts set forth in the table above; and those in which R³¹Is an o-tolyl radical, R³²Is a m-tolyl group, and R³³Is a p-tolyl group having the subscripts set forth in the table; and those in which R³¹Is a 1-naphthyl group, and is,R³²is a m-tolyl group, and R³³Is a p-tolyl group having the subscripts set forth in the table; and those in which R³¹Is an o-tolyl radical, R³²Is a 2-naphthyl group, and R³³Is a p-tolyl group having the subscripts set forth in the table; and finally those, wherein R³¹Is an o-isopropylphenyl radical, R³²Is a 2-naphthyl group, and R³³Is a p-tolyl group having the subscripts set forth in the table; and mixtures of these phosphites.

Phosphites of the formula IIb can be obtained as follows:

a) reacting a phosphorus trihalide with a compound selected from the group consisting of R³¹OH，R³²OH，R³³OH and R³⁴OH or a mixture thereof to obtain a dihalo-phosphoric monoester,

b) reacting the dihalophosphoric monoester with a compound selected from the group consisting of R³¹OH，R³²OH，R³³OH and R³⁴An alcohol of the group OH or mixtures thereof to obtain a dihalophosphodiester, and

c) reacting the above monohalophosphoric acid diester with a compound selected from the group consisting of R³¹OH，R³²OH，R³³OH and R³⁴OH or mixtures thereof to obtain phosphites of formula IIb.

The reaction can be carried out in three separate steps. It is also possible to combine two of the three steps, for example a) in combination with b) or b) in combination with c). Alternatively, all steps a), b), and c) may be combined with each other.

Selected from the group consisting of³¹OH，R³²OH，R³³OH and R³⁴The appropriate parameters and amounts of the alcohol of OH or mixtures thereof can be readily determined by performing several simple preliminary experiments.

Suitable phosphorus trihalides are in principle all phosphorus trihalides, of which Cl, Br, I are preferred, Cl being particularly preferably used as halide, and mixtures thereof. Can also be usedMixtures of identical or different halogen-substituted phosphines as phosphorus trihalides, e.g. PCl₃. Further details regarding the reaction conditions in the production process of phosphites of the formula IIb and regarding the workup are disclosed in DE-A19953058.

It is also possible to use the phosphites of the formula IIb as different phosphite mixtures as ligands. The mixture can be formed, for example, in the preparation of the phosphite of formula IIb.

In one embodiment of the process of the present invention, the phosphorus-containing ligand of the catalyst and/or the free phosphorus-containing ligand is selected from at least one multidentate P-containing ligand selected from the group consisting of phosphites, phosphonites, phosphinites, phosphines, and mixed P-containing ligands or combinations of these members, and at least one monodentate P-containing ligand selected from tritolyl phosphite and phosphites of the formula IIb, wherein R is³¹，R³²And R³³Independently selected from o-isopropylphenyl, m-tolyl, and p-tolyl, R³⁴Is phenyl, x is 1 or 2, and y, z, and p are independently 0, 1, or 2, provided that x + y + z + p is 3; and mixtures thereof.

Examples of multidentate P-containing ligands include the following:

1) compounds of formulae I, II, III, IV, and V disclosed in U.S. patent No. 5,723,641;

2) compounds of formulae I, II, III, IV, V, VI, and VII disclosed in U.S. patent No. 5,512,696, such as the compounds used in examples 1-31 therein;

3) compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, and XV disclosed in U.S. Pat. No. 5,821,378, such as the compounds used in examples 1-73 therein;

4) compounds of formulae I, II, III, IV, V, and VI in the disclosure of U.S. patent No. 5,512,695, such as the compounds used in examples 1-6 therein;

5) compounds of formula I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, and XIV disclosed in U.S. patent No. 5,981,772, such as the compounds used in examples 1-66 therein;

6) compounds disclosed in U.S. Pat. No. 6,127,567, such as the compounds used in examples 1-29 therein;

7) compounds of formulae I, II, III, IV, V, VI, VII, VIII, IX, and X disclosed in U.S. patent No. 6,020,516, such as the compounds used in examples 1-33 therein;

8) compounds disclosed in U.S. Pat. No. 5,959,135, such as the compounds used in examples 1-13 therein;

9) compounds of formulae I, II, and III disclosed in U.S. patent No. 5,847,191;

10) compounds disclosed in U.S. Pat. No. 5,523,453, such as compounds of formulae 1,2, 3,4, 5,6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and 21, among others;

11) compounds disclosed in U.S. Pat. No. 5,693,843, such as compounds of formulae I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, and XIII, such as the compounds used in examples 1-20 therein;

12) compounds of formulae V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, and XXVI disclosed in U.S. Pat. No. 6,893,996;

13) compounds disclosed in published patent application WO 01/14392, for example compounds described in formulas V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XXII, and XXIII therein;

14) chelating compounds disclosed in U.S. Pat. No. 6,242,633, such as compounds of formulae If, Ig, and Ih;

15) compounds disclosed in U.S. patent No. 6,521,778, such as compounds of formulae I, Ia, Ib, and Ic, e.g., compounds referred to as ligands I and II;

16) compounds disclosed in published patent application WO 02/13964, for example compounds of formulae Ia, Ib, Ic, Id, Ie, If, Ig, Ih, Ii, Ij, and Ik, for example compounds referred to as ligands 1,2, 3,4, 5, and 6;

17) compounds disclosed in german patent application DE 10046025;

18) chelating compounds disclosed in U.S. patent No. 7,022,866, such as compounds of formulas 1 and 2, e.g., compounds referred to as ligands 1 and 2;

19) compounds disclosed in U.S. published patent application No. 2005/0090677, such as compounds of formulae 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n, 1o, 2, and 3;

20) compounds disclosed in U.S. published patent application No. 2005/0090678, such as compounds of formulae 1 and 2, e.g., compounds referred to as ligands 1,2, 3,4, 5, and 6;

21) compounds disclosed in published patent application WO 2005/042547, for example compounds of formulae 1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n, 1o, 2,3, 4, 5, and 6, for example compounds referred to as ligands 1,2, 3, and 4;

22) chelating compounds disclosed in U.S. patent No. 6,169,198, such as compounds of formula I;

23) compounds disclosed in U.S. patent No. 6,660,877, such as compounds of formulae I, II, and III, such as the compounds used in examples 1-27 therein;

24) compounds disclosed in U.S. patent No. 6,197,992, such as compounds of ligands a and B: and

25) compounds disclosed in U.S. patent No. 6,242,633, such as compounds of formula I, Ia, Ib, Ic, Id, Ie, If, Ig, and Ih.

These references also disclose methods for preparing the multidentate ligands of formula I.

Further examples of ligands which form highly active catalysts in combination with nickel (for the hydrocyanation of 1, 3-butadiene or 3-pentenenitrile and the isomerization of 2-methyl-3-butenenitrile to 3-pentenenitrile) are bidentate phosphite ligands having the following structural formula:

(R¹O)₂P(OZO)P(OR¹)₂，

formula IIIa

Formula IIIb formula IIIc

Wherein in IIIa, IIIb, and IIIc, R¹Is phenyl, unsubstituted or substituted by one or more C₁-C₁₂Alkyl or C₁-C₁₂Alkoxy substitution; or naphthyl, which is unsubstituted or substituted by one or more C₁-C₁₂Alkyl or C₁-C₁₂Alkoxy substitution; and Z¹Independently selected from the group consisting of: structural formulae IV, V, VI, VII, and VIII:

and wherein

R²，R³，R⁴，R⁵，R⁶，R⁷，R⁸And R⁹Independently selected from the group consisting of:H，C₁-C₁₂alkyl, and C₁-C₁₂An alkoxy group; x is O, S, or CH (R)¹⁰)；

R¹⁰Is H or C₁-C₁₂An alkyl group;

and wherein

R²⁰And R³⁰Independently selected from the group consisting of: h, C₁-C₁₂Alkyl, and C₁-C₁₂An alkoxy group; and CO₂R¹³，

R¹³Is C₁-C₁₂Alkyl or C₆-C₁₀Aryl, unsubstituted or substituted by C₁-C₄Alkyl substitution;

w is O, S, or CH (R)¹⁴)；

R¹⁴Is H or C₁-C₁₂An alkyl group;

wherein R is¹⁵Selected from the group consisting of: h, C₁-C₁₂Alkyl, and C₁-C₁₂Alkoxy and CO₂R¹⁶；

R¹⁶Is C₁-C₁₂Alkyl or C₆-C₁₀Aryl, unsubstituted or substituted by C₁-C₄Alkyl substitution.

In the formulae IIIa, IIIb, IIIc, and IV to VIII, C₁-C₁₂Alkyl, and C₁-C₁₂The alkoxy group may be straight chainOr branched.

It is to be understood that structural formulae IIIa, IIIb, and IIIc can represent a single compound or a mixture of different compounds having the formulas shown.

Examples of bidentate phosphite ligands useful in the process of the present invention include those having the formulae IX through XXXII, shown below, wherein for each formula, R¹⁷Selected from the group consisting of: methyl, ethyl or isopropyl, and R¹⁸And R¹⁹Independently selected from H or methyl:

further examples of bidentate phosphite ligands useful in the process of the present invention include ligands selected from members of the group represented by formulas XXXIII and XXXIV, wherein all similar reference symbols have the same meaning, except as otherwise expressly defined below.

Formula XXXIII formula XXXIV

each R⁴⁵Independently selected from the group consisting of methyl, ethyl and primary hydrocarbyl of 3 to 6 carbon atoms; and is

R⁴²，R⁴³，R⁴⁴，R⁴⁶，R⁴⁷And R⁴⁸Each of which is independently selected from the group consisting of: h, an aryl group and a primary, secondary or tertiary hydrocarbyl group of 1 to 6 carbon atoms.

Some ligands useful in the catalyst compositions of the present invention are generally described in U.S. Pat. Nos. 6,171,996 and 5,512,696, and are exemplified by the formulae XXXIII and XXXIV defined above. In one preferred ligand of formula XXXIII (ligand "A" in the examples), each R is⁴¹Is isopropyl, each R⁴⁵Is methyl, R⁴²，R⁴⁶，R⁴⁷And R⁴⁸Each is hydrogen, and R⁴³And R⁴⁴Each is methyl. In a second preferred ligand of formula XXXIII (ligand "B" in the examples), each R is⁴¹Is isopropyl, each R⁴⁵Is methyl, R⁴²，R⁴⁶And R⁴⁸Are each hydrogen, and R⁴³，R⁴⁴And R⁴⁷Are each methyl. In one preferred ligand of formula XXXIV (ligand "C" in the examples), each R is⁴¹Is isopropyl, each R⁴⁵Is methyl, and R⁴⁶，R⁴⁷And R⁴⁸Each is hydrogen.

It will be appreciated that the above formula is a two-dimensional representation of a three-dimensional molecule, and that rotation around chemical bonds can occur in the molecule, resulting in configurations other than those shown. For example, rotation of the carbon-carbon bonds between the 2-and 2' -positions around the bridging groups of biphenyls and octahydrobinaphthyls of formula XXXIII and formula XXXIV, respectively, can bring the two phosphorus atoms in each formula closer to each other and can allow the phosphite ligand to bind to nickel in a bidentate fashion.

The P-containing ligands used in the present invention can be prepared by any suitable synthetic means known in the art. For example, in general, multidentate P-containing ligands can be synthesized in a manner similar to the methods described in U.S. Pat. nos. 6,171,996 and 5,512,696, both of which are incorporated herein by reference. For example, the reaction of 2 equivalents of an ortho-substituted phenol with phosphorus trichloride affords the corresponding phosphine hypochlorite (phosphorochloridite). The phosphine hypochlorite reacts with the desired substituted biphenol or octahydrobinaphthol in the presence of triethylamine to give a bidentate phosphite ligand. The crude bidentate phosphite ligand may be post-treated by the methods described in U.S. Pat. No. 6,069,267, which is incorporated herein by reference. As disclosed therein, bidentate phosphite ligand product mixtures may typically comprise the desired product in a selectivity of from about 70% to about 90%, with other phosphite by-products, such as monodentate phosphites, making up the balance of the product mixture.

The multidentate P-containing ligand as such or a mixture of multidentate P-containing ligands and at least one monodentate P-containing ligand is suitable, i.e. suitably used in the process of the present invention, if the ligand or ligand mixture provides acceptable results according to at least one of the protocols of the 2PN hydrocyanation test method indicated herein. The 2PN hydrocyanation test method utilizes three protocols that differ in the method of delivering HCN to the reaction mixture. A catalyst composition comprising zero-valent nickel and a multidentate P-containing ligand is prepared by first reacting a zero-valent nickel compound Ni (COD) in which the COD is 1, 5-cyclooctadiene₂Combined with a multidentate P-containing ligand in a toluene solvent. The resulting catalyst composition is then contacted with a solution comprising cis-2 PN and a lewis acid promoter. The next step is to contact the reaction solution with anhydrous, uninhibited HCN according to one of three protocols at about 50 ℃ for about 16 hours. The molar ratio of promoter to nickel present in the reaction mixture is about 0.96/1; the molar ratio of multidentate P-containing ligand to zero-valent nickel in the reaction mixture is in the range of about 1/1 to about 1.2/1; and the 2PN to nickel suppression molar ratio is from about 110/1 to about 130/1.

Acceptable results according to the 2PN hydrocyanation test method are those in which the conversion of 2PN (i.e., cis-2 PN and trans-2 PN) to dinitriles is at least 0.1% according to at least one protocol of the 2PN hydrocyanation test method. Also included in the 2PN conversion is the conversion of any 3PN and/or 4PN from isomerization of 2PN to dinitriles. As used herein, the term dinitrile includes ADN, MGN, and 2-ethylsuccinonitrile. Analytical methods such as gas chromatography can be used to determine the amount of dinitriles produced. Acceptable results according to the 2PN hydrocyanation test method indicate the ability of the ligand or mixture of ligands to form an active catalyst in the catalyst composition that converts cis-2 PN to useful products, such as dinitriles, 3PN and 4PN, under the conditions of the 2PN hydrocyanation test method.

The multidentate P-containing ligands used in the catalyst compositions used in the present invention can be prepared by any suitable synthetic method known in the art, for example as disclosed in at least some of the references disclosing examples of multidentate P-containing ligands. For example, the multidentate P-containing ligand of formula II can be synthesized as described in U.S. patent No. 6,171,996, which is incorporated herein by reference. For ligand "a", for example, the reaction of 2 equivalents of o-cresol with phosphorus trichloride provided the corresponding phosphine hypochlorite. The phosphine hypochlorite is reacted with 3, 3 '-di-isopropyl-5, 5', 6,6 '-tetramethyl-2, 2' -biphenol in the presence of triethylamine to provide the ligand "a". The crude bidentate phosphite ligand may be post-treated by the methods described in U.S. Pat. No. 6,069,267, which is incorporated herein by reference. As disclosed herein, a mixture of bidentate phosphite ligand products may typically comprise the desired product at a selectivity of from about 70% to about 90%, and other phosphite by-products, such as monodentate phosphites, comprising the balance of the product mixture. Bidentate phosphite ligands by themselves or mixtures of these bidentate/monodentate phosphite ligands are suitable for use in the present invention.

The catalyst composition used in the process should ideally be substantially free of carbon monoxide, oxygen and water, and can be carried out or prepared in situ according to techniques well known in the art, as disclosed in U.S. patent application No. 6,171,996. For example, the catalyst composition may be formed by contacting a bidentate phosphite ligand with a zero-valent nickel compound having a ligand that is readily displaced by a multidentate P-containing ligand, such as Ni (COD)₂，Ni[P(O-o-C₆H₄CH₃)₃]₃And Ni [ P (O-O-C)₆H₄CH₃)₃]₂(C₂H₄) All of which are well known in the art, among which 1, 5-Cyclooctadiene (COD), tris (O-tolyl) phosphite [ P (O-O-C)₆H₄CH₃)₃]And ethylene (C)₂H₄) Are readily substituted ligands. Elemental nickel, preferably nickel powder, when combined with a halogenated catalyst, as described in U.S. Pat. No. 3,903,120, is also a suitable source of zero-valent nickel. Alternatively, a divalent nickel compound may be combined with a reducing agent in the presence of a multidentate P-containing ligand, thereby acting as a source of zero-valent nickel in the reaction. Suitable divalent nickel compounds include those of the formula NiY₂Wherein Y is a halide, a carboxylate, or an acetylacetonate. Suitable reducing agents include metal borohydrides, metal aluminum hydroxides, metal alkyl Zn, Fe, Al, Na, or H₂. See, for example, U.S. patent No. 6,893,996, which is incorporated herein by reference.

In the catalyst composition, the multidentate P-containing ligand may be present in excess of the amount theoretically possible for coordinating with nickel in a given time unless it detracts from the beneficial aspects of the invention. For example, the nature of the catalyst composition of the ligands of formulae XXXIII and XXXIV is such that an effective catalyst can be formed at any molar ratio of ligand to nickel, but the preferred range of ligand to nickel molar ratio is from about 1/1 to about 4/1.

The pentenenitrile hydrocyanation process may be carried out in the presence of at least one lewis acid promoter, which affects both the activity and selectivity of the catalyst system. As described in the prior art, the cocatalyst may be an inorganic or organometallic compound in which the cation is selected from: scandium, titanium, vanadium, chromium, manganese, iron, cobalt, copper, zinc, boron, aluminum, yttrium, zirconium, niobium, molybdenum, cadmium, rhenium, lanthanum, erbium, ytterbium, samarium, tantalum, and tin. Examples include, but are not limited to, BPh₃、ZnCl₂、CoI₂、SnCl₂、PhAlCl₂、Ph₃Sn(O₃SC₆H₅CH₃) And Cu (O)₃SCF₃)₂. Preferred promoters include zinc chloride ZnCl₂FeCl, iron (II) chloride₂And manganese (II) chloride MnCl₂And mixtures thereof. U.S. patent No. 4,874,884 describes how a synergistic combination of promoters can be selected to increase the catalytic activity of a catalyst system. The molar ratio of promoter to nickel present in the reaction may be, for example, in the range of about 0.1/1 to about 10/1, such as in the range of about 0.5/1 to about 1.2/1.

The catalyst composition may be dissolved in a solvent that is non-reactive with and miscible with the hydrocyanation reaction mixture. Suitable solvents include, for example, aliphatic and aromatic hydrocarbons having from 1 to 10 carbon atoms, and nitrile solvents such as acetonitrile. Alternatively, 3PN, mixtures of isomerized pentenenitriles, mixtures of isomerized methylbutenenitrile, mixtures of isomerized pentenenitrile and isomerized methylbutenenitrile, or reaction products from previous reaction stages may be used to dissolve the catalyst composition.

In order to maximize pentenenitrile hydrocyanation ratio while minimizing catalyst consumption by oxidation of active nickel by HCN, the hydrocyanation reaction of the present invention should be conducted in a reactor system that provides efficient mass transfer of pentenenitriles, HCN and catalyst and efficient removal of the heat of reaction. Such reactor systems are known in the art. In at least one embodiment, the hydrocyanation reaction of the present invention may be effectively carried out in a continuously stirred tank reactor in which the reactor product is thoroughly backmixed with the reaction mixture. In such reactor systems, it is expected that the kinetics of the hydrocyanation reaction will be governed primarily by the composition of the reactor product. In another suitable embodiment, the hydrocyanation reaction of the present invention may be carried out in a reactor system disclosed in U.S. patent No. 4,382,038. In such a reactor system, the first reaction zone comprises a plurality of stages in series, wherein the product from one stage is continuously directed to subsequent stages, and HCN is added to each stage. The effluent from the first reaction zone and comprising zero-valent nickel catalyst, unreacted pentenenitrile, unreacted HCN, and dinitrile product is then sent to a second reaction zone where its temperature can be controlled and no HCN is added to the effluent.

For example, the continuous hydrocyanation reaction may be conducted at between about 20 ℃ to about 90 ℃, such as in the range of about 35 ℃ to about 70 ℃, or such as in the range of about 45 ℃ to about 60 ℃.

Although atmospheric pressure is suitable for practicing the invention, higher and lower pressures may be used. In this regard, pressures of, for example, from about 0.5 to about 10 atmospheres (about 50.7 to about 1013kPa) may be used. Higher pressures, up to 20,000kPa and above, may be used if desired, but any benefit that may be obtained thereby may not be considered reasonable in view of the added cost of these operations.

HCN, which is substantially free of carbon monoxide, oxygen, ammonia, and water, can be introduced to the reaction as a vapor, a liquid, or a mixture of the two. Alternatively, cyanohydrin may be used as the source of HCN. See, for example, U.S. Pat. No. 3,655,723.

The overall feed molar ratio of HCN to zero-valent nickel can be, for example, in the range of about 100/1 to about 3000/1, such as in the range of about 300/1 to about 2000/1. At reactor start-up, the reaction vessel may be partially filled with, for example, a solution of the catalyst composition in the substrate pentenenitrile or the reaction product from a preceding reaction stage, after which all reactors start to be fed. The continuous removal of the reaction product can be started when the desired liquid level has built up in the reaction vessel.

At least one potential advantage of using the above-described catalyst composition for hydrocyanation of ethylenically unsaturated nitriles may be realized when the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture is maintained from about 0.2/1 to about 10/1, with a reduction in yield loss caused by concurrent isomerization of 3PN to 2 PN. Control over the ratio of 2PN concentration to 3PN concentration in the reaction mixture within this range can be established by: controlling X, i.e., the total feed molar ratio of 2PN to all unsaturated nitriles, by selecting a value for X in the range of about 0.001 to about 0.5, and controlling Z, i.e., the total feed molar ratio of HCN to all unsaturated nitriles, by selecting a value for Z in the range of about 0.5 to about 0.99, such that the quotient Q has a value in the range of about 0.2 to about 10, wherein

Wherein 3PN is 3-pentenenitrile and 4PN is 4-pentenenitrile. Similarly, when the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture is maintained from about 1/1 to about 5/1, a reduction in yield loss caused by concurrent isomerization of 3PN to 2PN can be achieved. Control of this ratio within this range may be established by: by selecting a value for X in the range of about 0.01 to about 0.25, and by selecting a value for Z in the range of about 0.70 to about 0.99, X and Z are controlled such that Q is in the range of about 1 to about 5.

While not limited to any particular process, establishing a total feed molar ratio of 2PN to all unsaturated nitriles can be accomplished by at least two different processes and/or combinations thereof. For example, the overall feed molar ratio of 2PN to all unsaturated nitriles can be controlled by adding 2PN produced in a separate process or by directly recycling 2PN from the reaction product mixture in the process. The first method involves obtaining 2PN produced by different processes or prepared in separate production facilities. The desired feed molar ratio can then be achieved by blending the thus obtained 2PN with the other substrate pentenenitrile isomers in suitable proportions. Alternatively, 2PN may be produced from a pentenenitrile hydrocyanation process. For example, 2PN in the reaction product of the present invention can be physically separated from the dinitrile product and catalyst composition along with other unreacted unsaturated nitriles by vacuum distillation. Establishing the total feed molar ratio of 2PN to all unsaturated nitriles may be accomplished, for example, by returning at least a portion of a stream selected from the group consisting of the fifth stream, the eleventh stream, the twelfth stream, the fifteenth stream, and combinations thereof to the reaction mixture. (see below for the parts of these streams). The streams containing the recovered 2PN can be recycled and/or blended with each other and/or other streams, such as refined 3PN, in suitable proportions to constitute a feed to the reaction of the present invention having the desired molar ratio of ethylenically unsaturated nitriles. The stream comprising 2PN may be substantially free of other nitriles, or 2PN may be present in a process stream comprising additional nitriles.

In order that recovery of the catalyst composition may be carried out by liquid-liquid extraction by contact with an extractant, phase separation of the extract and raffinate phases must occur in the extraction process. U.S. Pat. No. 3,773,809, incorporated herein in its entirety, discloses a process for separating organophosphorus compounds or zero-valent nickel complexes of organophosphorus compounds from a product stream having a paraffin or cycloalkane solvent at a temperature of about 0 ℃ to about 100 ℃ to produce a multiphase mixture, wherein the organophosphorus compounds and their metal complexes are contained predominantly in the hydrocarbon phase and the organic mononitriles and dinitriles and degradation products are contained in separate phases. The reference also states that the composition of the product stream must be controlled so that the molar ratio of organic mononitriles to organic dinitriles contained therein is less than about 0.65 and preferably about 0.3 to form a heterogeneous mixture; the separation of nickel is most effective for systems rich in dinitriles. Three methods for controlling the molar ratio of mononitriles to dinitriles are provided to control the level of hydrocyanation of mononitriles, i.e., the degree of conversion of mononitriles to dinitriles, e.g., by flash distillation to remove mononitriles and to introduce additional amounts of dinitriles. U.S. Pat. No. 3,773,809 also discloses that in the extraction process, the ratio of organophosphorus compound to extracted nitrile can range from 1/1000 parts to 90/100 parts; and the ratio of hydrocarbon to organophosphorus compound can be in the range of 2/1 parts to 100/1 parts, all parts being parts by weight. The reference discloses monodentate P-containing ligands.

U.S. Pat. No. 6,936,171 claims a process for recovering diphosphite-containing compounds from a mixture comprising diphosphite-containing compounds and organic mononitriles and organic dinitriles using liquid-liquid extraction, wherein the molar ratio of organic mononitrile present to organic dinitrile is from about 0.65 to about 2.5, and wherein the extraction solvent is a saturated or unsaturated alkane or a saturated or unsaturated cycloalkane. The reference discloses that the preferred ratio of mononitrile to dinitrile ranges from 0.01 to 2.5. The reference discloses that catalysts comprising diphosphite complexes of Ni allow recovery by liquid-liquid extraction at higher ratios of organic mononitriles to organic dinitriles than described in U.S. patent No. 3,773,809. As a result, under hydrocyanation reaction conditions that produce mononitrile to dinitrile ratios in excess of 0.65, unreacted mononitrile does not necessarily have to be removed prior to extraction to recover the catalyst. The process can be carried out to recover different bidentate P-containing ligands and their nickel complex catalysts, including bidentate P-containing ligands selected from the group consisting of bidentate phosphites and bidentate phosphinites. The introduction of monodentate phosphites into the catalyst mixture can improve extraction recovery.

The reaction product mixture of the process of the present invention is suitable for catalyst composition recovery by liquid-liquid extraction by contact with an extractant, wherein, for example, the catalyst composition comprises at least one bidentate P-containing ligand, such as a bidentate phosphite or bidentate diphosphonite, and the molar ratio of mononitriles to dinitriles is about 2.5 or less. The reaction product mixture is also suitable for recovery of a catalyst composition by liquid-liquid extraction by contact with an extractant, wherein, for example, the catalyst composition comprises a monodentate P-containing ligand and the mononitrile to dinitrile molar ratio is less than about 0.65. U.S. Pat. No. 6,936,171 and published U.S. patent application No. 2007/0260086 describe conditions for recovering a catalyst composition comprising a bidentate P-containing ligand and a monodentate P-containing ligand, wherein the molar ratio of mononitrile to dinitrile is adjusted or is not adjusted prior to liquid-liquid extraction. When the reaction product mixture is not suitable for catalyst composition recovery by liquid-liquid extraction in contact with an extractant under the conditions disclosed in the following section, this will be apparent when liquid-liquid extraction is attempted, since no phase separation will occur.

After removing a reaction product mixture suitable for catalyst composition recovery by liquid-liquid extraction, wherein the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture is in the range of about 0.2/1 to about 10/1, at least a portion of the reaction product mixture is extracted with an extractant to obtain an extract phase comprising the extractant and the catalyst composition, and a raffinate phase comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition degradation products, and optionally the extractant. The extractant is selected from the group consisting of aliphatic hydrocarbons having a boiling point in the range of about 30 ℃ to about 135 ℃, cycloaliphatic hydrocarbons, and mixtures thereof. For example, n-pentane, n-hexane, n-heptane, n-octane, the corresponding C having a boiling point in the specified range, may be added₅-C₈Aliphatic hydrocarbon isomers, cyclopentane, cyclohexane, cycloheptane, methylcyclohexane, alkyl-substituted alicyclic hydrocarbons having boiling points within the specified ranges, and mixtures thereof are used as the extracting agent. The extractant is preferably anhydrous, e.g., having less than about 100ppm water, or e.g., less than about 50ppm water, or e.g., less than about 10ppm water. The extractant may be dried by suitable methods known to those skilled in the art, for example by adsorption or azeotropic distillation.

The extraction of the reaction product mixture may be carried out in any suitable apparatus known to those skilled in the art. Examples of conventional equipment suitable for this extraction include countercurrent extraction columns, cascaded mixed settlers, or a combination of cascaded mixed settlers and columns. For example, a countercurrent extraction column equipped with a metal sheet packing as a dispersion element can be used. Countercurrent extraction can be carried out in a stirred extraction column with spacing such as a rotating tray column contactor.

The weight ratio of extractant to reaction product mixture fed to the extraction process can range from about 0.1 to greater than about 10. For example, the extraction is carried out at a weight ratio of about 0.4 to 2.5, or for example at a ratio of about 0.5 to about 1.5. The pressure in the extraction apparatus is from about 0.1 bar to about 10 bar, such as from 0.5 bar to about 5 bar, or such as from about 1.0 bar to about 2.5 bar. The extraction is carried out at a temperature of from about 0 ℃ to about 100 ℃, for example from about 20 ℃ to about 90 ℃, or for example from about 30 ℃ to about 80 ℃.

The extract phase comprising the extractant and the catalyst composition is distilled to obtain a first stream comprising the extractant and a second stream comprising the catalyst composition. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation can be carried out in one or more evaporation stages (evaporation stages) and distillation columns. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

In one embodiment, the distillation apparatus comprises at least one distillation column. The distillation column may be provided with a structured packing section at the feed position to prevent catalyst entrainment in the first stream and to produce the appropriate number of separation stages. In one embodiment, the extract phase is distilled in two stages, wherein each distillation column has a bottoms temperature below about 150 ℃. In one embodiment, the extract phase is distilled in two stages, wherein each distillation column has a bottoms temperature below about 120 ℃.

The pressure in the distillation apparatus is variable to obtain the bottom temperature as described above. The pressure in the distillation apparatus for the extract phase may be in the range of from 0.001 to about 2.0 bar, such as in the range of from 0.01 to 1.7 bar, or such as in the range of from 0.05 to 1.5 bar. The distillation is carried out in such a way that the bottom temperature of the distillation column is in the range of from 40 ℃ to about 150 ℃, or for example from 80 ℃ to 140 ℃, or for example from 90 ℃ to 120 ℃.

In the distillation of the extract phase, a first stream comprising the extractant is obtained. The first stream comprises about 85 to about 100 wt% extractant. The first stream may also comprise from about 0 to about 15 weight percent ethylenically unsaturated nitriles, including, for example, 2M2BN, 2PN, 3PN, and 4 PN. Optionally, at least a portion of the first stream comprising the extractant can be returned to the extraction process. Optionally, the first stream may also be purified to separate the extractant from the ethylenically unsaturated nitrile and return the ethylenically unsaturated nitrile to the hydrocyanation reaction before returning the extractant to the extraction process.

The first stream may be obtained as a vapour stream in at least one condenser at the top of at least one distillation column, wherein the extractant is at least partly condensed in the at least one condenser from the vapour stream of the distillation column and is returned as reflux to the distillation column at least partly in the liquid state.

Alternatively, the distillation can be carried out with a direct contact condenser so that the condensation takes place in the column cross-section, for example by providing it with a structured column filling, a collecting cup below the filling, liquid discharge means from the collecting cup, a transfer pump conduit connected to the liquid discharge means, a pump and a heat exchanger and at least one device for adding the liquid stream pumped by the transfer pump to the filling on the collecting cup.

In the distillation of the extract phase, a second stream comprising the catalyst composition is obtained. Optionally, ethylenically unsaturated nitrile may be added to the bottom of the column to improve ease of handling the stream if necessary, for example to limit precipitation of the catalyst composition in the concentrated second stream. The second stream may be obtained as a bottoms product of a column and comprises about 0 to about 10 wt% of the extractant. The remainder of the second stream comprises the catalyst composition, which optionally comprises catalyst composition degradation products, ethylenically unsaturated nitriles and dinitriles.

Optionally, to increase the concentration of nickel in the catalyst composition to a desired level, at least a portion of the second stream may be introduced into the reactor, wherein the at least a portion of the second stream is contacted with nickel chloride and a reducing metal that is more electropositive than nickel in the presence of a nitrile solvent, as disclosed in U.S. patent No. 6,893,996. The stream exiting the reactor is the fifteenth stream and includes the catalyst composition. The nitrile solvent may, for example, be an ethylenically unsaturated nitrile present in the second stream. Optionally, at least a portion of the fifteenth stream can be returned to the hydrocyanation reaction mixture as part of the catalyst composition feed, as well as part of the ethylenically unsaturated nitrile feed. If it is desired to maintain or change the molar ratio of the P-containing ligand to nickel, the P-containing ligand may be added to the reactor, wherein the second stream is contacted with nickel chloride and a reducing metal. The added P-containing ligand may be, for example, a recycled P-containing ligand that has been separated from the process and returned to the catalyst composition, or a previously unused P-containing ligand.

Optionally, at least a portion of the second stream is introduced to a 3PN production process comprising 1, 3-butadiene hydrocyanation, 2-methyl-3-butenenitrile isomerization, or a combination thereof. For example, in U.S. Pat. nos. 3,496,215; 3,536,748; 5,693,843; 5,821,378; 5,981,772; and 6,020,516 (incorporated herein in their entirety) disclose catalyst compositions and reaction conditions for 1, 3-butadiene hydrocyanation and 2-methyl-3-butenenitrile isomerization.

Distilling the raffinate phase comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition degradation products, and extractant to obtain a third stream comprising extractant and a fourth stream comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation may be carried out in one or more evaporation stages and distillation columns. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

The pressure in the distillation apparatus for the raffinate phase may be in the range 0.1 to 2.0 bar, for example 0.2 to 1.3 bar. The distillation is carried out in such a way that the bottom temperature of the bottom of the distillation apparatus is from 40 to 150 c, for example from 80 to 130 c.

In one embodiment, the distillation apparatus comprises at least one distillation column operating at sub-atmospheric pressure. In one embodiment, the distillation apparatus comprises at least one distillation column operating above one atmosphere pressure. The distillation column may be provided with a structured packing section to produce a suitable number of separation stages.

The third stream comprises about 80 to about 100 wt%, for example about 90 to about 100 wt% of the extractant. The third stream may also contain about 0 to about 20 weight percent, for example about 0 to about 10 weight percent, ethylenically unsaturated nitriles, including for example 2M2BN, 2M3BN, 2PN, 3PN, and 4 PN. Optionally, at least a portion of the third stream comprising the extractant can be returned to the extraction process. Optionally, at least a portion of the third stream may be combined with at least a portion of the first stream, and the mixed stream comprising the extractant may optionally be returned to the extraction process.

The third stream can be obtained as a vapour stream in at least one condenser at the top of the distillation column, wherein the extractant is at least partly condensed in the at least one condenser from the vapour stream of the distillation column and is returned as reflux to the distillation column at least partly in the liquid state.

In the distillation of the raffinate phase, a fourth stream comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products is obtained. The fourth stream may be obtained as a bottoms product of a column and comprises from about 0 to about 10 wt% of the extractant, for example from about 0.001 to about 6 wt% of the extractant. The remainder of the fourth stream includes ethylenically unsaturated nitriles, including 2PN, 3PN, 4PN, and 2M2BN, dinitriles, and catalyst composition degradation products.

Distilling the fourth stream to obtain a fifth stream comprising ethylenically unsaturated nitriles and a sixth stream comprising ADN, MGN, and catalyst composition degradation products. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation may be carried out in one or more evaporation stages and distillation columns. The distillation column may have one or more liquid or vapor side draws. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

The pressure in the distillation apparatus of the fourth stream may be in the range of from 0.001 to 1.0 bar, for example from 0.02 to 0.1 bar. The distillation is carried out in such a way that the bottom temperature of the distillation column is from 80 ℃ to 250 ℃, for example from 150 ℃ to 220 ℃.

In one embodiment, the distillation apparatus comprises at least one distillation column operating at atmospheric pressure. The distillation column may be provided with a structured packing section to produce a suitable number of separation stages.

In the distillation of the fourth stream, a fifth stream comprising ethylenically unsaturated nitriles is obtained. The fifth stream may comprise about 50 to about 100 wt.%, for example about 70 to about 100 wt.%, ethylenically unsaturated nitriles, with the balance comprising extractant and optionally other compounds.

In the distillation of the fourth stream, a sixth stream comprising ADN, MGN, and catalyst composition degradation products is obtained. The sixth stream may be included as a bottoms product and comprises from about 0 to 2 wt% ethylenically unsaturated nitrile, for example from 0.01 to about 0.5 wt% ethylenically unsaturated nitrile. The remainder of the sixth stream includes catalyst composition degradation products and dinitriles.

Distilling the sixth stream to obtain a seventh stream comprising ADN and MGN and an eighth stream comprising catalyst composition degradation products. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation may be carried out in one or more evaporation stages and distillation columns. The column is equipped with one or more side cuts. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators. Particularly preferred evaporators are the following: which enables very low evaporator surface temperatures and short contact times on the evaporator, thereby minimizing thermal damage to the material being evaporated.

In the distillation of the sixth stream, the pressure in the distillation apparatus may range from 0.0001 to 0.5 bar, for example from 0.001 to 0.05 bar. The distillation is carried out in such a way that the bottom temperature of the distillation apparatus is from 100 ℃ to 250 ℃, or for example from 140 ℃ to 200 ℃.

In the distillation of the sixth stream, a seventh stream comprising ADN and MGN is obtained. The seventh stream comprises greater than about 98 wt.% dinitriles.

In the distillation of the sixth stream, an eighth stream comprising degradation products of the catalyst composition is obtained. The eighth stream may be obtained as a bottoms product and additionally comprises residual dinitriles. When cleaning the catalyst composition degradation products from the process, as much dinitriles as possible are separated from the catalyst composition degradation products.

Distilling the seventh stream to obtain a ninth stream comprising MGN and a tenth stream comprising ADN. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation may be carried out in one or more evaporation stages and distillation columns. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

In one embodiment, the distillation apparatus comprises at least one distillation column operating below atmospheric pressure. The distillation column may be provided with a structured packing section to produce a suitable number of separation stages.

In the distillation of the seventh stream, a ninth stream comprising MGN is obtained. The ninth stream comprises less than about 10 wt% ADN, for example less than about 5 wt% ADN.

In the distillation of the seventh stream, a tenth stream comprising ADN is obtained. The tenth stream may be obtained as a bottoms product of a column and comprises more than about 99 wt% ADN, for example more than about 99.9 wt% ADN.

The fifth stream may also contain compounds that cannot be converted to ADN. Examples of such compounds include 2M2BN and valeronitrile. Compounds that cannot be converted to ADN will accumulate in the recycle loop of the process unless they are removed and washed. Such a distillation process is described in U.S. Pat. No. 3,564,040 which purges cis-2 PN and 2M2BN from the pentenenitrile stream recycled to the pentenenitrile hydrocyanation reactor. The present invention constitutes a simpler and more economical process which does not require expensive distillation for cleaning compounds which cannot be converted to ADN. For example, in the fifth stream, the total amount of compounds that cannot be converted to ADN may be in the range of from about 1 wt% to about 50 wt%, or, for example, greater than about 10 wt%, or, for example, greater than about 20 wt%. Optionally, at least a portion of the fifth stream is withdrawn to purge at least a portion of compounds that cannot be converted to ADN from the production process. By having the content of these compounds build up in the fifth stream prior to purging a portion of the stream from the process, the associated cost of purging valuable ethylenically unsaturated nitriles, such as 2PN, 3PN, and 4PN, will be reduced from the fifth stream. The weight fraction of the amount of the fifth stream that is purged can be from about 1 wt% to about 50 wt%, such as less than 10 wt%, or such as less than 5 wt%.

Optionally, distilling at least a portion of the fifth stream comprising ethylenically unsaturated nitriles to obtain an eleventh stream comprising cis-2 PN and a twelfth stream comprising 3 PN. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation can be carried out in one or more evaporation stages (evaporation stages) and distillation columns. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

In one embodiment, the distillation apparatus comprises at least one distillation column. The distillation column may be provided with a structured packing section to produce a suitable number of separation stages.

In the distillation of the fifth stream, an eleventh stream comprising cis-2 PN is obtained. The eleventh stream is enriched in cis-2 PN, 2M2BN, and valeronitrile as compared to the fifth stream. The eleventh stream also comprises, for example, 3 PN. If desired, at least a portion of the eleventh stream from the process can be purged to remove compounds that cannot be converted to ADN. Alternatively, or in combination with the purging of the eleventh stream, at least a portion of the eleventh stream can be returned to the reaction mixture as part of the ethylenically unsaturated nitrile feed.

An eleventh stream can be obtained as a vapor stream in at least one condenser at the top of the distillation column, wherein cis-2 PN is at least partially condensed in the at least one condenser from the vapor stream of the distillation column and returned as reflux to the distillation column at least partially in the liquid state.

Alternatively, the distillation can be carried out with a direct contact condenser so that the condensation takes place in the column cross-section, for example by providing it with a structured column filling, a collecting cup below the filling, a liquid discharge from the collecting cup, a transfer pump conduit with a pump and a heat exchanger connected to the liquid discharge, and at least one device for adding the liquid stream pumped by the transfer pump to the filling on the collecting cup.

In the distillation of the fifth stream, a twelfth stream comprising 3PN is obtained. The twelfth stream may be obtained as a bottom product of the column and is enriched with 3PN compared to the fifth stream. The twelfth stream also contains other mononitriles such as trans-2 PN. Optionally, at least a portion of the twelfth stream is returned to the reaction mixture as part of the ethylenically unsaturated nitrile feed.

As discussed above, the fifth stream is optionally distilled to obtain an eleventh stream and a twelfth stream. Other applications of the fifth stream are also possible. For example, at least a portion of the fifth stream may be returned to the reaction mixture as part of the ethylenically unsaturated nitrile feed. At least a portion of the fifth stream can be mixed with the second stream comprising the catalyst composition, and optionally additional P-containing ligands, either before or after the second stream is contacted with nickel chloride in the presence of a reducing metal that is more electropositive than nickel, to obtain a fifteenth stream that can be returned to the reaction mixture. At least a portion of the fifth stream may be withdrawn to purge at least a portion of compounds from the production process that cannot be converted to ADN and thereby limit their accumulation in the reaction zone and the polishing stream. These optional uses of the fifth stream may be performed alone or in combination with each other.

In all figures, the feed and withdrawal points for each reactor, extractor and distillation column are shown. It is to be understood that the possible locations of these feed points and withdrawal points are not necessarily specific to the location specified, and that the streams may also be introduced at other feed points and obtained from other withdrawal points not specified in the figure, depending on the conditions used to operate the reactor, extractor or distillation column, and the degree of separation required in the case of an extractor or distillation column.

FIG. 1 schematically illustrates one embodiment of the process of the present invention. Referring to FIG. 1, HCN, a catalyst composition (abbreviated as "cat" in the figure), and an ethylenically unsaturated nitrile (abbreviated as "sub" in the figure) are continuously fed into a reaction zone 30 in the presence of at least one Lewis acid to form a reaction mixture, and by selecting a value for X in the range of from about 0.001 to about 0.5; and controlling the total feed molar ratio of 2PN to all unsaturated nitriles (X) and the total feed molar ratio of HCN to all unsaturated nitriles (Z) by selecting the value of Z in the range of about 0.5 to about 0.99 such that the value of quotient Q is in the range of about 0.2 to about 10, wherein

Reaction product mixture P, comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition, and catalyst composition degradation products, wherein the ratio of the concentration of 2PN to the concentration of 3PN in the reaction mixture is in the range of from about 0.2/1 to about 10/1, is withdrawn from reaction zone 30 and introduced into extractor 34. Stream EA containing the extractant is also introduced into extractor 34.

In extractor 34, reaction product mixture P is extracted with an extractant to obtain an extract phase EP comprising the extractant AND the catalyst composition AND a raffinate phase RP comprising AND, MGN, ethylenically unsaturated nitrile, catalyst composition degradation products, AND the extractant. As a result of the extraction, the extract phase EP is devoid of dinitriles, ethylenically unsaturated nitriles, and catalyst composition degradation products as compared to the reaction product mixture. The raffinate RP is devoid of catalyst composition as compared to the reaction product mixture.

The extract phase EP is introduced into a distillation column 36, wherein the extract phase EP is distilled to obtain a first stream 1 comprising the extractant and a second stream 2 comprising the catalyst composition. As a result of the distillation, the first stream 1 is enriched with extractant and lacks catalyst composition, compared to the extract phase EP. In comparison with the extract phase EP, the second stream 2 is rich in catalyst composition and lacks extractant.

Figure 2 schematically illustrates another embodiment of the process of the present invention wherein the raffinate phase is refined. Referring to fig. 2, the raffinate RP obtained as described above is introduced into a distillation column 38, wherein the raffinate RP is distilled to obtain a third stream 3 comprising the extractant and a fourth stream 4 comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products. As a result of the distillation, the third stream 3 is enriched in extractant and deficient in ADN, MGN, and catalyst composition degradation products as compared to the raffinate RP. The fourth stream 4 is rich in ADN, MGN, and catalyst composition degradation products and lacks an extractant as compared to the raffinate RP.

The fourth stream 4 is introduced into a distillation column 40 wherein the fourth stream 4 is distilled to obtain a fifth stream 5 comprising the ethylenically unsaturated nitrile and a sixth stream 6 comprising ADN, MGN, and catalyst composition degradation products. As a result of the distillation, fifth stream 5 is enriched in ethylenically unsaturated nitriles and is depleted in dinitriles, including ADN and MGN, and catalyst composition degradation products, as compared to fourth stream 4. Sixth stream 6 is enriched in dinitriles, including ADN and MGN, and catalyst composition degradation products, and is devoid of ethylenically unsaturated nitriles, as compared to fourth stream 4.

Sixth stream 6 is introduced into distillation column 42, where sixth stream 6 is distilled to obtain seventh stream 7 comprising dinitriles comprising ADN and MGN, and eighth stream 8 comprising catalyst composition degradation products. As a result of the distillation, seventh stream 7 is enriched in dinitriles comprising ADN and MGN and is devoid of catalyst composition degradation products, as compared to sixth stream 6. In comparison to sixth stream 6, eighth stream 8 is rich in catalyst composition degradation products and lacks dinitriles comprising ADN and MGN.

The seventh stream 7 is introduced into a distillation column 44, wherein the seventh stream 7 is distilled to obtain a ninth stream 9 comprising MGN and a tenth stream 10 comprising ADN. The ninth stream 9 is rich in MGN and deficient in ADN compared to the seventh stream 7. The tenth stream 10 is enriched in ADN and deficient in MGN compared to the seventh stream 7.

The fifth stream 5 is introduced into a distillation column 46, wherein the fifth stream 5 is distilled to obtain an eleventh stream 11 comprising cis-2 PN and a twelfth stream 12 comprising 3 PN. As a result of the distillation, the eleventh stream 11 is enriched in cis-2 PN and depleted in 3PN compared to the fifth stream 5. The twelfth stream 12 is enriched in 3PN and lacks cis-2 PN as compared to the fifth stream 5. Optionally, at least a portion of the eleventh stream 11 or the twelfth stream 12 may be returned to the reaction mixture in the reaction zone 30 (not shown in fig. 2).

FIG. 3 schematically illustrates one embodiment of the process of the present invention. Referring to fig. 3, second stream 2 comprising the catalyst composition is introduced into reactor 48, where second stream 2 is contacted with nickel chloride and a reducing metal, which is more electropositive than nickel, in the presence of a nitrile solvent to obtain fifteenth stream 15. The fifteenth stream 15 includes the catalyst composition and is returned to the reaction zone 30 as part of the catalyst composition fed to the reaction mixture. The optional addition of a P-containing ligand to reactor 48 is not shown in figure 3.

In the case where the reaction product mixture is not suitable for catalyst composition recovery by liquid-liquid extraction, the molar ratio of organic mononitrile to organic dinitrile should be adjusted to a ratio wherein phase separation occurs upon contact with the extractant. The ratio of mononitrile to dinitrile can be adjusted, for example, by adding dinitrile to the reaction product mixture, or by removing a portion of the ethylenically unsaturated nitrile in the reaction product mixture (e.g., by distillation).

Distillation of the reaction product mixture may yield a thirteenth stream comprising ethylenically unsaturated nitriles, such as 2PN, 3PN, 4PN, and 2M2BN, and a fourteenth stream devoid of ethylenically unsaturated nitriles and comprising the catalyst composition, catalyst degradation products, ADN, and MGN. The distillation may be carried out in any suitable apparatus known to those skilled in the art. The distillation may be carried out in one or more distillation columns. The column may be equipped with one or more side cuts. Examples of conventional equipment suitable for such distillation include sieve tray columns, bubble tray columns, columns with conventional packing, randomly packed columns or single stage evaporators, such as falling film evaporators, thin film evaporators, flash distillation evaporators, multiphase helical tube evaporators, natural circulation evaporators or forced circulation flash evaporators.

The distillation of the reaction mixture can be carried out in one stage or in a series of multiple stages carried out at different temperatures and pressures. The evaporator stage can be designed as a distillation column, wherein operation as a rectification column or as a stripping column is possible. In one embodiment, the evaporator stage operates as a distillation column in stripping mode.

The actual distillation conditions selected will depend in part on the thermal stability of the catalyst composition used. For more thermally stable catalyst compositions, higher distillation temperatures can be used. With respect to less thermally stable catalyst compositions, lower distillation temperatures should be used to minimize the yield of catalyst composition degradation products.

The thirteenth stream may be obtained as a vapor stream in at least one condenser at the top of the distillation column, wherein the ethylenically unsaturated nitrile is at least partially condensed from the vapor stream of the distillation column in the at least one condenser and is at least partially returned to the distillation column in the liquid state. The fourteenth stream may be obtained as the bottom product of the column.

Extracting at least a portion of the fourteenth stream with an extractant to obtain an extractant phase comprising the extractant and the catalyst composition and a raffinate phase comprising ADN, MGN, catalyst composition degradation products, ethylenically unsaturated nitriles, and optionally the extractant. The extractant is selected from the group consisting of: aliphatic hydrocarbons having a boiling point in the range of about 30 ℃ to about 135 ℃, alicyclic hydrocarbons, and mixtures thereof. For example, n-pentane, n-hexane, n-heptane, n-octane, the corresponding C having a boiling point in the specified range, may be added₅-C₈Aliphatic hydrocarbon isomers, cyclopentane, cyclohexane, cycloheptane, methylcyclohexane, alkyl-substituted alicyclic hydrocarbons having boiling points within the specified ranges, and mixtures thereof are used as the extracting agent. The extractant is preferably anhydrous, e.g., having less than about 100ppm water, or e.g., less than about 50ppm water, or e.g., less than about 10ppm water. The extractant may be dried by suitable methods known to those skilled in the art, for example by adsorption or azeotropic distillation.

The extraction of the fourteenth stream can be carried out in any suitable apparatus known to those skilled in the art, as described above in connection with the extraction of the reaction product mixture, and in the same manner as described above for the extraction of the reaction product mixture. The extract and raffinate phases were refined as described in the previous section. The extract phase comprising the extractant and the catalyst composition is distilled to obtain a first stream comprising the extractant and a second stream comprising the catalyst composition. Optionally, in order to increase the concentration of nickel in the catalyst composition to a desired level, at least a portion of the second stream may be introduced into a reactor where it is contacted with nickel chloride and a reducing metal that is more electropositive than nickel to obtain a fifteenth stream comprising the catalyst composition. The nitrile solvent may be, for example, an ethylenically unsaturated nitrile present in the second stream. Optionally, at least a portion of the fifteenth stream can be returned to the hydrocyanation reaction mixture as part of the catalyst composition feed. If it is desired to maintain or increase the molar ratio of ligand to nickel, a P-containing ligand may be added while the second stream is contacted with nickel chloride and a reducing metal. The added P-containing ligand may be, for example, a recycled P-containing ligand that has been separated from the process and returned to the catalyst composition, or a previously unused P-containing ligand.

Distilling the raffinate phase comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition degradation products, and extractant to obtain a third stream comprising extractant and a fourth stream comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products. Distilling the fourth stream to obtain a fifth stream comprising ethylenically unsaturated nitriles and a sixth stream comprising ADN, MGN, and catalyst composition degradation products. Distilling the sixth stream to obtain a seventh stream comprising ADN and MGN and an eighth stream comprising catalyst composition degradation products. Distilling the seventh stream to obtain a ninth stream comprising MGN and a tenth stream comprising ADN.

Streams that also include at least one lewis acid, such as the reaction product mixture, raffinate phase, fourth stream, sixth stream, fourteenth stream, and combinations thereof, may be contacted with ammonia to at least partially separate the metal chloride lewis acid and other components of the stream. Removal of metal cations from solutions in nitriles by contact with anhydrous ammonia is disclosed, for example, in U.S. patent No. 3,766,241, which is incorporated herein in its entirety. The ammonia is contacted with the lewis acid-containing stream, for example by bubbling it through the stream, and the insoluble material formed may be separated from the solution by settling, filtration, centrifugation, or other methods known to those skilled in the art. The contacting with ammonia may be carried out in any suitable apparatus known to those skilled in the art.

FIG. 4 schematically illustrates one embodiment of the process of the present invention. As discussed with respect to FIGS. 1 and 2, the reaction withdrawn from reaction zone 30The product mixture P is introduced into the extractor 34 together with a stream EA comprising the extractant. In extractor 34, reaction mixture P is extracted with an extractant to obtain an extract phase EP comprising the extractant and the catalyst composition and a raffinate phase RP comprising ADN, MGN, ethylenically unsaturated nitrile, catalyst composition degradation products, and optionally the extractant. The extract phase EP is introduced into a distillation column 36, wherein the extract phase EP is distilled to obtain a first stream 1 and a second stream 2. The raffinate RP is introduced into a distillation column 38, wherein distillation of the raffinate RP yields a third stream 3 and a fourth stream 4 comprising ADN, MGN, ethylenically unsaturated nitrile, and catalyst composition degradation products. The reaction product mixture P, the raffinate phase RP, and the fourth stream 4 may also comprise at least one lewis acid, such as zinc chloride. Referring to fig. 4, fourth stream 4 also comprises zinc chloride, which is introduced into reactor 50, wherein anhydrous ammonia (NH) is made available₃) With fourth stream 4. Separating the insoluble material formed. As a result of the treatment with ammonia, the fourth stream treated with ammonia is depleted of zinc chloride compared to the fourth stream 4 prior to the ammonia treatment. The ammonia-treated fourth stream may be introduced into distillation column 40 and further refined as described in the section above (not shown in fig. 4).

Whether the reaction product mixture is directly extracted or extracted after distillation to remove a portion of the ethylenically unsaturated nitrile, a stream comprising a crude bidentate phosphite ligand mixture comprising phosphite ligands selected from members of the group represented by formulas XXXIII and XXXIV may be introduced into the extractor during the extraction of the reaction product mixture of the fourteenth stream. The formulae XXXIII and XXXIV are shown below, wherein all reference symbols have the same meaning, except where expressly limited to:

formula XXXIII formula XXXIV

each R⁴⁵Independently selected from the group consisting of: methyl, ethyl, and primary hydrocarbyl groups of 3 to 6 carbon atoms; and

each R⁴²，R⁴³，R⁴⁴，R⁴⁶，R⁴⁷And R⁴⁸Independently selected from the group consisting of: h, an aryl group, and a primary, secondary or tertiary hydrocarbyl group of 1 to 6 carbon atoms. The crude bidentate phosphite ligand mixture may be synthesized by any suitable synthetic means known in the art, as discussed in the previous section. The stream comprising the crude bidentate phosphite ligand mixture may be introduced into an extractor to increase the concentration of ligand to a desired level, for example in the second stream, since most of the ligand will partition into the extraction phase.

Embodiments falling within the scope of the present invention may be further understood on the basis of the following non-limiting examples.

Examples

The following method may be used to treat cis-2 PN prior to use in the hydrocyanation reaction. Cis-2-pentenenitrile (98%) produced from BD and 3PN hydrocyanation processes is commercially available from Sigma Aldrich chemical company. Hydroperoxide impurities are common in such agents and are generally detrimental to hydrocyanation catalyst performance. The hydroperoxide impurity can be measured and reduced in cis-2 PN, if desired, by titration, for example with triphenylphosphine, followed by purification by distillation. Distillation under a nitrogen atmosphere can be used to remove most of the oxygen, water and peroxides and heavy boil-off by taking, for example, a forecut (forecut), and a center cut during the distillation. The purified cis-2 PN of the center fraction may be transferred to a drying oven filled with an inert gas such as nitrogen, and it may be further dried by 3A molecular sieves, which have been subjected to drying and degassing under nitrogen.

Bis (1, 5-cyclooctadiene) nickel (0), Ni (COD)₂And anhydrous ZnCl₂Purchased from commercial suppliers and also stored under a nitrogen atmosphere in a dry box.

Three protocols for the 2PN hydrocyanation test method are as follows. All three versions had a starting c2PN of about 19 wt%.

Scheme #1Exposure to HCN vapor:

under an inert atmosphere such as anhydrous nitrogen or argon by adding Ni (COD)₂(0.039g) dissolved in toluene (2.79g) to prepare Ni (COD)₂And (3) solution. A toluene solution of the multidentate P-containing ligand, or a mixture of ligands comprising the multidentate P-containing ligand to be tested, or other suitable solvent solution (0.230mL of 0.062mol total multidentate P-containing ligand/L toluene) is treated with Ni (COD)₂The solution (0.320mL) was treated and thoroughly mixed to provide a catalyst solution having a molar ratio of zero-valent nickel/multidentate P-containing ligand of about 1/1. By dissolving ZnCl₂(0.017g in 1.02g of cis-2 PN) to prepare cis-2-pentenenitrile (cis-2 PN)/ZnCl₂And (3) solution. A sample of the catalyst solution (0.100mL) was taken with cis-2 PN/ZnCl₂Solution (0.025 mL); the resulting mixture had a cis-2 PN/nickel molar ratio of about 123 and ZnCl of about 0.96/1₂The nickel/nickel molar ratio. The mixture was heated to about 50 ℃ during 16 hours and exposed to HCN vapor supplied from an uninhibited, reservoir of liquid HCN (619 mmHg or 82.5kPa vapor pressure at 20 ℃) at room temperature. Next, the reaction mixture was cooled to room temperature, treated with acetonitrile (0.125mL), and the amounts of ADN, MGN, and 2-ethylsuccinonitrile produced were analyzed by gas chromatography to calculate the percentage of 2PN converted to dinitrile.

Scheme #2Continuous flow of HCN vapor diluted with nitrogen over the reaction solution:

in an inert atmosphere, e.g. anhydrous nitrogen (N)₂) Or under argon, adding Ni (COD)₂The solution was prepared by mixing Ni (COD)₂(0.039g) was dissolved in toluene (2.79 g). A toluene solution of the multidentate P-containing ligand, or a mixture of ligands comprising the multidentate P-containing ligand to be tested, or other suitable solvent solution (0.230mL of 0.062mol total multidentate P-containing ligand/L toluene) is treated with Ni (COD)₂The solution (0.320mL) was treated and thoroughly mixed to provide a catalyst solution having a molar ratio of zero-valent nickel/multidentate P-containing ligand of about 1/1. By dissolving anhydrous ZnCl₂(0.017g in 1.02g of cis-2 PN) to prepare cis-2-pentenenitrile (cis-2 PN)/ZnCl₂And (3) solution. A sample of the catalyst solution (0.100mL) was taken with cis-2 PN/ZnCl₂Solution (0.025 mL); the resulting mixture had a cis-2 PN/nickel molar ratio of about 123 and ZnCl of about 0.96/1₂The nickel/nickel molar ratio. HCN/N is produced by bubbling anhydrous nitrogen through anhydrous, uninhibited liquid HCN at 0 deg.C₂The gas mixture (about 35% HCN vol/vol) was purged (about 1 to about 5mL/min) over the catalyst/c 2PN mixture heated to about 50 ℃. After 16 hours, the reaction mixture was then cooled to room temperature, treated with acetonitrile (0.125mL), and the amounts of ADN, MGN, and 2-ethylsuccinonitrile produced were analyzed by gas chromatography to calculate the percentage of 2PN conversion to dinitriles.

Scheme #3Sealed vial:

under an inert atmosphere such as anhydrous nitrogen or argon, adding Ni (COD)₂The solution was prepared by mixing Ni (COD)₂(0.065g) was dissolved in toluene (2.79 g). A toluene solution of the multidentate P-containing ligand, or a mixture of ligands comprising the multidentate P-containing ligand to be tested, or other suitable solvent solution (0.230mL of 0.062mol total multidentate P-containing ligand/L toluene) is treated with Ni (COD)₂The solution (0.320mL) was treated and thoroughly mixed to provide a catalyst solution having a molar ratio of zero-valent nickel/multidentate P-containing ligand of about 1/1. By mixing anhydrous ZnCl₂(0.0406g), freshly distilled, uninhibited liquid HCN (0.556g), and cis-2 PN (1.661g) to produce cis-2-pentenenitrile (cis-2 PN)/HCN/ZnCl₂And (3) solution. In 2mL GC vialsIn (1), a sample of the catalyst solution (0.092mL) was used cis-2 PN/HCN/ZnCl₂Solution (0.034mL) treatment, followed by sealing the vial with an aluminum septum cap; the resulting mixture had a cis-2 PN/nickel molar ratio of about 123, an HCN/nickel molar ratio of about 123, and a ZnCl ratio of about 0.96/1₂The nickel/nickel molar ratio. The mixture was heated to about 50 ℃ over a period of 16 hours. Next, the reaction mixture was cooled to room temperature, treated with acetonitrile (0.125mL), and the amounts of ADN, MGN, and 2-ethylsuccinonitrile produced were analyzed by gas chromatography to calculate the percentage conversion of 2PN to dinitrile.

In the following examples, all operations were carried out under nitrogen atmosphere using a dry box or standard Schlenk techniques, unless otherwise indicated. An example of the continuous hydrocyanation process of the present invention is carried out in a single stage 18mL glass Continuous Stirred Tank Reactor (CSTR) of the general design already described in U.S. Pat. Nos. 4,371,474, 4,705,881, and 4,874,884, the entire contents of which are incorporated herein by reference. The reactor consisted of a crimp-baffle round bottom glass vessel equipped with a jacket to control the temperature of the reaction mixture with fluid flow from an externally controlled, fluid heated, warm bath. All reactants were introduced into the reaction vessel through a syringe pump, through a side arm equipped with a rubber septum. The reactor is equipped with overflow arms through which the reaction product flows by gravity into the product receptacle. Stirring and mixing of the reaction mixture was provided by magnetic stirring. A small nitrogen purge was continuously supplied to the vapor space of the reactor to maintain an inert atmosphere.

Trans-3 PN (95 wt%) and cis-2 PN (98 wt%) for the hydrocyanation experiments described below were from commercial ADN plants that hydrocyanate BD and pentenenitriles. Trans-3 PN and cis-2 PN produced from BD and pentenenitrile hydrocyanation processes are commercially available from Sigma Aldrich chemical company. Each pentenenitrile was distilled under a nitrogen atmosphere and then stored in a nitrogen-filled dry box.

Examples 1-5 and comparative examples a-C were conducted and example 6 was conducted using a bidentate phosphite ligand in which the multidentate P-containing ligand is (or, in the case of example 6) a member selected from the group represented by formula XXXIII or formula XXXIV, wherein all similar reference numerals have the same meaning except as further explicitly defined:

formula XXXIII formula XXXIV

Wherein each R⁴¹Independently selected from the group consisting of: primary or secondary hydrocarbyl of 1 to 6 carbon atoms;

Ligand "a" of example 1 may be prepared by any suitable synthetic means known in the art. For example, 3, 3 ' -diisopropyl-5, 5 ', 6,6 ' -tetramethyl-2, 2 ' -biphenol can be prepared by the method disclosed in U.S. published patent application No. 2003/0100802, which is incorporated herein by reference, wherein 4-methyl thymol can be oxidatively coupled to a substituted biphenol in the presence of copper chloride hydroxide (copper chloride) -TMEDA complex (TMEDA is N, N ' -tetramethylethylenediamine) and air.

Phosphine hypochlorite of o-cresol ((C)₇H₇O)₂PCl) may be prepared by the method disclosed in U.S. published patent application 2004/0106815, which is incorporated herein by reference. In order to selectively form such hypochloritesThe phosphine is acidified by adding anhydrous triethylamine and o-cresol separately and simultaneously in a controlled manner to PCl dissolved in a suitable solvent under temperature controlled conditions₃In (1).

The reaction of phosphine hypochlorite with 3, 3 '-diisopropyl-5, 5', 6,6 '-tetramethyl-2, 2' -biphenol to form the desired ligand "a" can be carried out, for example, according to the method disclosed in U.S. patent No. 6,069,267, which is incorporated herein by reference. Phosphine hypochlorite can be reacted with 3, 3 '-diisopropyl-5, 5', 6,6 '-tetramethyl-2, 2' -biphenol in the presence of an organic base to form ligand "a" which can be isolated according to techniques well known in the art, as described in U.S. patent No. 6,069,267. The monodentate phosphite impurity of ligand "a" prepared by this method has the following structure:

likewise, ligand "B" may be prepared from phosphine hypochlorite of 3, 3 '-diisopropyl-5, 5', 6,6 '-tetramethyl-2, 2' -biphenol and 2, 4-xylenol, ((C)₈H₉O)₂PCl. The monodentate phosphite impurity in ligand "B" prepared by this method has the following structure:

likewise, ligand "C" may be prepared from phosphine hypochlorite of 3, 3 '-diisopropyl-5, 5', 6,6 ', 7, 7', 8, 8 '-octahydro-2, 2' -binaphthol, and o-cresol, prepared by the method described in U.S. patent application No. 2003/0100803, (C)₇H₇O)₂PCl. The monodentate phosphite impurity in ligand "C" prepared by this method will have the following structure:

the anhydrous, uninhibited HCN feed to the reactor was supplied as a Pentenenitrile (PN) solution (40 wt% HCN). The composition of the pentenenitriles used to prepare the feed solution is determined by the desired pentenenitrile feed composition to the reactor. The amount of methylbutenenitrile in the pentenenitrile feed solution is negligible. As outlined in U.S. Pat. No. 6,120,700, by Ni (COD)₂With a slight excess of the corresponding bidentate phosphite ligand (about 1.2 to 1.4 molar equivalents per nickel) in toluene solvent at ambient temperature to synthesize a ligand-Ni catalyst composition. After removal of the toluene solvent and volatile materials under vacuum, a corresponding amount of anhydrous lewis acid promoter was added to the solid residue of the catalyst composition and the entire mixture was dissolved in the corresponding pentenenitrile mixture. Thus, the resulting pentenenitrile solution containing the catalyst composition and promoter was fed to the reactor as described below.

At start-up, the reaction vessel was filled with about 9mL of a pentenenitrile solution containing the catalyst composition and promoter. Then, a continuous hydrocyanation reaction is started by opening the feed of a pentenenitrile solution containing the composition and the promoter, and of an HCN solution. Periodic samples of the reaction product flowing into the receiver were analyzed by Gas Chromatography (GC) analysis to determine the composition of the nitrile product used in calculating the reaction conversion and yield.

Defining:

experimental PN series C₅H₇All pentenenitrile isomers of N, including empirical formula C₅H₇All methyl butenenitrile isomers of N

2PN cis-and trans-2-pentenenitrile

3PN cis-and trans-3-pentenenitrile

4 PN-4-pentenenitrile

DN class ═ empirical formula C₆H₈N₂All dinitrile isomers of (including ADN, MGN and ESN)

ADN-adiponitrile

MGN-2-methylglutaronitrile

ESN ═ ethylsuccinonitrile

g/hr-g/hr

Conversion is the molar amount of reaction/molar amount of feed

Yield as the molar amount generated/molar amount of reaction (3PN +4PN)

Molar% of DN class-the molar fraction in the reaction product DN class/(PN class + DN class)

2 molar% of PN feed 2PN/(PN type + DN type) molar fraction in the reactor feed

The mole% of the 2PN product is the mole fraction in the reaction product 2PN/(PN + DN types)

Molar% of 3PN product-the molar fraction in the reaction product 3PN/(PN type + DN type)

Linearity (ADN mol/mol of (ADN + MGN + ESN) produced

Example 1

Use of ligand "A" as shown below and use of FeCl₂The continuous hydrocyanation process of the present invention is demonstrated as a lewis acid promoter.

Ligand "A"

Target reaction rate 1.6X10^-4Molar amount of HCN/liter-sec of

The temperature is 50 DEG C

The mole% of the 2PN feed is 12.8%

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.29
3，4PN(3PN+4PN)	1.01
		2PN	0.15
Ni catalyst, calculated as Ni metal	0.0010
		Total ligands^b	0.029
FeCl₂Co-catalyst	0.0015

Note that:^aHCN except for PN solvent.^bA mixture of ligand "a" and the corresponding monodentate phosphite as described above.

The total feed molar ratio of 2PN to all unsaturated nitriles was about 0.13 and the total feed molar ratio of HCN to all unsaturated nitriles was about 0.75.

The average GC analysis of reaction product samples taken from 92 to 100 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	86％
		Mol% of DN class	73.6％
2 moles% of PN product	14.0％
		Mole% of 3PN product	11.8％
2PN yield	1.5％
		Degree of linearity	94.2％
Yield of ADN	92.8％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 1.2.

Example 2

Using the ligand "A" and using ZnCl₂The continuous hydrocyanation process of the present invention is demonstrated as a lewis acid promoter.

Target reaction rate 1.6x10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mole% of the 2PN feed is 20.6%

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.29
3，4PN(3PN+4PN)	0.94
		2PN	0.25
Ni catalyst, calculated as Ni metal	0.0013
		Total ligands^b	0.027
ZnCl₂Co-catalyst	0.0020

The overall feed molar ratio of 2PN to all unsaturated nitriles was about 0.21 and the overall feed molar ratio of HCN to all unsaturated nitriles was about 0.70.

The average GC analysis of reaction product samples taken from 49 to 53 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	90.7％
		Mol% of DN class	71.9％
2 moles% of PN product	20.3％
		Mole% of 3PN product	7.2％
2PN yield	0.0％
		Degree of linearity	95.0％
Yield of ADN	95.0％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 2.8.

Comparative example A

The following is the use of the ligand "A" and of ZnCl₂Comparative example of a continuous hydrocyanation reaction as cocatalyst and without addition of 2PN to the reactor feed.

Target reaction rate 2.3X 10^-4Molal HCN/liter-sec

The temperature is 50 DEG C

The mol% of the 2PN feed is 0.1%^c

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.38
3，4PN(3PN+4PN)	1.63
		2PN	0.0016
Ni catalyst, calculated as Ni metal	0.0018
		Total ligands^b	0.045
ZnCl₂Co-catalyst	0.0048

Note that:^aHCN except for PN solvent.^bA mixture of ligand "a" and the corresponding monodentate phosphite as described above.^c2PN impurities in the 3PN starting material.

The overall feed molar ratio of 2PN to all unsaturated nitriles was about 0.001 and the overall feed molar ratio of HCN to all unsaturated nitriles was about 0.70.

The average GC analysis of reaction product samples taken from 46 to 54 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	71.1％
		Mol% of DN class	68.7％
2 moles% of PN product	2.1％
		Mole% of 3PN product	28.0％
2PN yield	2.5％
		Degree of linearity	94.9％
Yield of ADN	92.5％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 0.08.

Example 3

Use of ligand "B" as shown below and use of FeCl₂The continuous hydrocyanation process of the present invention is demonstrated as a lewis acid promoter.

Ligand "B"

Target reaction rate 1.6X10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mole% of the 2PN feed is 15.4%

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.29
3，4PN(3PN+4PN)	0.95
		2PN	0.175
Ni catalyst, calculated as Ni metal	0.0013
		Total ligands^b	0.029
FeCl₂Co-catalyst	0.0019

Note that:^aHCN except for PN solvent.^bA mixture of ligand "B" and the corresponding monodentate phosphite as described above.

The overall feed molar ratio of 2PN to all unsaturated nitriles was about 0.15 and the overall feed molar ratio of HCN to all unsaturated nitriles was about 0.80.

The average GC analysis of reaction product samples taken from 69 to 78 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	92.3％
		Mol% of DN class	77.4％
2 moles% of PN product	15.6％
		Mole% of 3PN product	6.4％
2PN yield	0.3％
		Degree of linearity	94.7％
Yield of ADN	94.4％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 2.4.

Example 4

Using the ligand "B" and using ZnCl₂The continuous hydrocyanation process of the present invention is demonstrated as a lewis acid promoter.

Target reaction rate 1.6X10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mole% of the 2PN feed is 14.9%

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.29
3，4PN(3PN+4PN)	0.96
		2PN	0.17
Ni catalyst, calculated as Ni metal	0.0013
		Total ligands^b	0.029
ZnCl₂Co-catalyst	0.0020

The total feed molar ratio of 2PN to all unsaturated nitriles was about 0.15 and the total feed molar ratio of HCN to all unsaturated nitriles was about 0.77.

The average GC analysis of reaction product samples taken from 66 to 73 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	90.7％
		Mol% of DN class	76.2％
2 moles% of PN product	15.5％
		Mole% of 3PN product	7.7％
2PN yield	0.7％
		Degree of linearity	95.4％
Yield of ADN	94.7％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 2.0.

Comparative example B

The following is the use of ligand "B" and the use of ZnCl₂Comparative example of a continuous hydrocyanation reaction as cocatalyst and without addition of 2PN to the reactor feed.

Target reaction rate 2.3X 10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mol% of the 2PN feed is 0.3%^c

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.38
3，4PN(3PN+4PN)	1.63
		2PN	0.0049
Ni catalyst, calculated as Ni metal	0.0018
		Total ligands^b	0.049
ZnCl₂Co-catalyst	0.0048

Note that:^aHCN except for PN solvent.^bA mixture of ligand "B" and the corresponding monodentate phosphite as described above.^c2PN impurities in the 3PN starting material.

The overall feed molar ratio of 2PN to all unsaturated nitriles was about 0.003, while the overall feed molar ratio of HCN to all unsaturated nitriles was about 0.70.

The average GC analysis of reaction product samples taken from 45 to 48 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	73.9％
		Mol% of DN class	71.5％
2 moles% of PN product	2.1％
		Mole% of 3PN product	25.2％
2PN yield	2.5％
		Degree of linearity	95.4％
Yield of ADN	93.0％

Example 5

The use of the ligand "C" shown below and the use of ZnCl₂The continuous hydrocyanation process of the present invention is demonstrated as a lewis acid promoter.

Ligand "C"

Target reaction rate 1.6X10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mole% of the 2PN feed is 20.4%

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.29
3，4PN(3PN+4PN)	0.94
		2PN	0.24
Ni catalyst, calculated as Ni metal	0.0013
		Total ligands^b	0.029
ZnCl₂Co-catalyst	0.0020

Note that:^aHCN except for PN solvent.^bA mixture of ligand "C" and the corresponding monodentate phosphite as described above.

The total feed molar ratio of 2PN to all unsaturated nitriles was about 0.20, and the total feed molar ratio of HCN to all unsaturated nitriles was about 0.73.

The average GC analysis of reaction product samples taken from 71 to 79 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	90.0％
		Mol% of DN class	70.4％
2 moles% of PN product	21.1％
		Mole% of 3PN product	7.9％
2PN yield	1.0％
		Degree of linearity	95.0％
Yield of ADN	94.1％

The ratio of the 2PN concentration to the 3PN concentration in the reaction mixture was about 2.7.

Comparative example C

The following is the use of the ligand "C" and of ZnCl₂Comparative example of a continuous hydrocyanation reaction as cocatalyst and without addition of 2PN to the reactor feed.

Target reaction rate 2.3X 10^-4Mol HCN/liter-sec

The temperature is 50 DEG C

The mol% of the 2PN feed is 0.4%^c

The target feed rates of the reaction components were as follows.

Reagent	Feed rate, g/hr
		HCN^a	0.40
3，4PN(3PN+4PN)	1.70
		2PN	0.0068
Ni catalyst, calculated as Ni metal	0.0019
		Total ligands^b	0.051
ZnCl₂Co-catalyst	0.0050

Note that:^aHCN except for PN solvent.^bA mixture of ligand "C" and the corresponding monodentate phosphite as described above.^c2PN impurities in the 3PN starting material.

The overall feed molar ratio of 2PN to all unsaturated nitriles was about 0.004, and the overall feed molar ratio of HCN to all unsaturated nitriles was about 0.70.

The average GC analysis of reaction product samples taken from 48 to 53 hours after the start of continuous flow indicated the following steady state results.

Conversion of 3, 4PN	72.6％
		Mol% of DN class	70.3％
2 moles% of PN product	2.1％
		Mole% of 3PN product	26.6％
2PN yield	2.4％
		Degree of linearity	94.9％
Yield of ADN	92.6％

Example 6

Example 6 shows the integrated continuous process of the present invention operating at steady state. This example uses a catalyst composition in which the multidentate P-containing ligand is a bidentate P-containing ligand referred to in the section above as "ligand B". Ligand B was prepared as described in the section above.

Ligand B, anhydrous NiCl, was prepared according to the method disclosed in U.S. Pat. No. 6,893,996₂Zinc powder and 3PN to make a catalyst composition, said U.S. patent No. 6,893,996 being incorporated herein by reference. The catalyst composition is used in the hydrocyanation described below.

A recycle stream comprising a total of more than 97 wt.% of 3PN and 4PN, ethylenically unsaturated nitriles and compounds not capable of being converted to ADN, and a refined 3PN stream comprising nitrile and zinc chloride feed in a catalyst composition comprising ligand B and zero-valent nickel, Ni (0) in a 1.2: 1 ligand B: Ni (0) molar ratio, in the presence of a zinc chloride co-catalyst and a catalyst composition, is contacted in a reaction zone consisting of a stainless steel draft tube, a back-mixed reactor. The combined feed to the reaction zone comprised a total of 54.3 wt.% 3PN and 4PN, 12.9 wt.% 2PN, 28.2 wt.% other ethylenically unsaturated nitriles, and 17.3 wt.% HCN, which resulted in a total feed molar ratio of 2PN to all unsaturated nitriles (ratio X) of about 0.14 and a total feed molar ratio of HCN to all unsaturated nitriles (ratio Z) of about 0.75. The molar ratio of HCN of the feed to Ni (0) of the feed was 450: 1, and the molar ratio of HCN of the feed to zinc chloride of the feed was 540: 1. The reaction zone was maintained at 50 ℃ with a residence time of about 10 hours to obtain a 3PN conversion of about 94%, where HCN is the limiting reactant, and produced a reaction mixture comprising about 10 wt% 2PN, about 3.3 wt% 3PN and 4PN in total, about 3.7 wt% MGN, about 69.0 wt% ADN, and about 0.4 wt% ESN. Thus, the ratio of the concentration of 2PN to the concentration of 3PN in the reaction product mixture is about 3.

The reaction product mixture was introduced into an extractor comprising a series of three mixer-settlers, which was maintained at 50 ℃. The weight ratio of cyclohexane extractant to reaction product mixture was 0.7. The extract phase obtained from the extractor contained about 85 wt% cyclohexane, about 6 wt% ethylenically unsaturated nitrile, less than about 2 wt% dinitrile, about 3.5 wt% ligand B, and about 0.12 wt% Ni (0). Cyclohexane was mixed with the raffinate from the second stage and fed to a third mixer-settler. The raffinate phase from the extractor contained about 12 wt% cyclohexane, about 10 wt% 2PN, about 13 wt% other ethylenically unsaturated nitriles, about 64 wt% dinitriles, and trace amounts of ligand B and catalyst composition degradation products.

The extract phase is introduced into a distillation column and continuously distilled. The column head pressure was about 4.8psia (0.33 bar) and the column bottom temperature was 100 ℃. A first stream is withdrawn from the column and comprises about 90 wt% cyclohexane, the remainder of the stream consisting of ethylenically unsaturated nitriles. The bottoms material is circulated through an external stream-heated exchanger, thereby heating the bottom of the column. To limit precipitation of the catalyst composition solids, the ethylenically unsaturated nitrile is introduced into the bottom of the column at a ratio of about 0.1 (wt/wt) to the column feed. A second stream comprising about 20 wt% ligand B and about 0.7 wt% Ni is obtained by withdrawing a portion from the bottom material of the recycle column, wherein the remainder of the stream consists of dinitriles, catalyst composition degradation products and ethylenically unsaturated nitriles.

The raffinate phase was introduced into a distillation column and distillation was continued to remove most of the cyclohexane. The column head pressure was about 4.5psia (0.31 bar) and the column bottom temperature was 90 ℃. A third stream is taken from the column and contains about 93 wt% cyclohexane, the remainder being ethylenically unsaturated nitriles. The fourth stream is obtained by withdrawing a portion of the bottoms from the recycle column and comprises about 2 wt% cyclohexane.

The fourth stream is introduced into an ammonia reactor wherein anhydrous ammonia is fed in a 2: 1 molar ratio to the zinc chloride in the feed. The product from the reactor is sent to a reactor/crystallizer. The product from the reactor/crystallizer was centrifuged to remove ammonia-zinc chloride solids.

The ammonia-treated fourth stream is introduced into a distillation column and continuously distilled. The column head pressure was about 1.2psia (0.083 bar) and the column bottom temperature was 202 ℃. A fifth stream comprising 6 wt% cyclohexane, 38 wt% 2PN, a total of 22 wt% 3PN and 4PN, and about 34 wt% compounds that cannot be converted to ADN is withdrawn from the top of the column. The bottom of the column is heated by circulating it through an external stream-heated exchanger. A sixth stream comprising 93.3 wt% ADN, 5.9 wt% MGN, and minor amounts of ethylenically unsaturated nitrile and catalyst composition degradation products is obtained by withdrawing a portion from the circulating bottoms material.

After withdrawing 2 wt% of the fifth stream to purge a portion of the compounds that cannot be converted to ADN by the production process and thereby limit their accumulation in the reaction zone and the polishing stream, another portion of the fifth stream is returned to the reaction zone as a recycle stream.

The sixth stream is introduced into the distillation apparatus and distillation is continued. The apparatus is operated at a pressure range of about 0.10psia (0.0069 bar) to about 0.40psia (0.028 bar), and a temperature range of about 160 ℃ to about 185 ℃. A seventh stream is withdrawn from the apparatus and comprises about 93 wt% ADN and 6.0 wt% MGN. An eighth stream is withdrawn from the apparatus and comprises about 75 wt% catalyst composition degradation products and about 20 wt% dinitriles.

The seventh stream is introduced into the distillation column and distillation is continued. The column head pressure was about 0.39psia (0.027 bar) and the column bottom temperature was about 200 ℃. A ninth stream is withdrawn from the reflux returned to the column and comprises a total of about 95 wt% MGN and ESN and about 2.0 wt% ADN. The bottom of the column is heated by circulating it through an external stream-heated exchanger. The tenth stream is obtained by withdrawing a portion of the bottoms from the recycle column and contains in excess of 99.9% ADN.

Although particular embodiments of the present invention have been described in the foregoing description, those skilled in the art will appreciate that the present invention is capable of numerous modifications, substitutions and rearrangements without departing from the spirit or essential attributes of the invention. Reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

1. A process for hydrocyanating an ethylenically unsaturated nitrile having 5 carbon atoms, the process comprising:

a) forming a reaction mixture comprising an ethylenically unsaturated nitrile having 5 carbon atoms, hydrogen cyanide, and at least one catalyst composition in the presence of at least one lewis acid by continuously feeding the ethylenically unsaturated nitrile, the hydrogen cyanide, and the at least one catalyst composition; wherein

The catalyst composition comprises zero-valent nickel and at least one bidentate phosphorus-containing ligand;

the bidentate phosphorus-containing ligand is selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, and a mixed phosphorus-containing ligand, or a combination of such members;

and the bidentate phosphorus-containing ligand provides an acceptable result in which the conversion of 2-pentenenitrile to dinitriles is at least 0.1%, according to at least one protocol of the 2-pentenenitrile hydrocyanation test method;

b) controlling X and Z such that the quotient Q has a value in the range of 0.2 to 10 by selecting a value for X in the range of 0.001 to 0.5 and a value for Z in the range of 0.5 to 0.99, wherein X is the total feed molar ratio of 2-pentenenitrile to all unsaturated nitriles and Z is the total feed molar ratio of hydrogen cyanide to all unsaturated nitriles, wherein

Wherein 3PN is 3-pentenenitrile and 4PN is 4-pentenenitrile;

c) withdrawing a reaction product mixture comprising adiponitrile, 2-methylglutaronitrile, ethylenically unsaturated nitriles, said catalyst composition, and catalyst composition degradation products; and wherein the ratio of the concentration of 2-pentenenitrile to the concentration of 3-pentenenitrile in the reaction mixture is in the range of from 0.2/1 to 10/1;

e) distilling the extract phase to obtain a first stream comprising the extractant and a second stream comprising the catalyst composition.

2. The process of claim 1, further comprising distilling the raffinate phase to obtain a third stream comprising the extractant and a fourth stream comprising adiponitrile, 2-methylglutaronitrile, ethylenically unsaturated nitriles, and catalyst composition degradation products.

3. The process of claim 2, further comprising distilling the fourth stream to obtain a fifth stream comprising ethylenically unsaturated nitriles and a sixth stream comprising adiponitrile, 2-methylglutaronitrile, and catalyst composition degradation products.

4. The process of claim 3, further comprising distilling the sixth stream to obtain a seventh stream comprising adiponitrile and 2-methylglutaronitrile and an eighth stream comprising catalyst degradation products.

5. The process of claim 4, further comprising distilling the seventh stream to obtain a ninth stream comprising 2-methylglutaronitrile and a tenth stream comprising adiponitrile.

6. The process of claim 5, further comprising returning at least a portion of the first stream, at least a portion of the third stream, or a combination thereof to the extraction.

7. The process of claim 5, wherein at least a portion of the fifth stream is returned to the reaction mixture.

8. The process of claim 5, wherein at least a portion of the second stream is combined with at least a portion of the fifth stream and optionally returned to the reaction mixture.

9. The process of claim 5, wherein the fifth stream further comprises compounds that cannot be converted to adiponitrile, and wherein at least a portion of the fifth stream is withdrawn to purge at least a portion of the compounds that cannot be converted to adiponitrile.

10. The process of claim 9, wherein in the fifth stream, the total content of compounds that cannot be converted to adiponitrile is greater than 10% by weight.

11. The process of claim 5, further comprising distilling at least a portion of the fifth stream to obtain an eleventh stream comprising cis-2-pentenenitrile and a twelfth stream comprising 3-pentenenitrile.

12. The method of claim 11, wherein at least a portion of the twelfth stream is returned to the reaction mixture.

13. The process of claim 1, further comprising contacting at least a portion of the second stream with nickel chloride and a reducing metal that is more electropositive than nickel in the presence of a nitrile solvent to obtain a fifteenth stream, and optionally, returning at least a portion of the fifteenth stream to the reaction mixture.

14. The process of claim 3, further comprising contacting ammonia with at least one stream selected from the group consisting of the reaction product mixture, the raffinate phase, the fourth stream, the sixth stream, and combinations thereof, wherein the reaction product mixture, the raffinate phase, the fourth stream, the sixth stream, and combinations thereof further comprise at least one Lewis acid.

15. The process of claim 1, wherein the extract phase is subjected to a two-stage distillation wherein the bottom temperature of each distillation column is 150 ℃ or less.

16. The process of claim 1, wherein the extract phase is subjected to a two-stage distillation wherein the temperature at the bottom of each distillation column is 120 ℃ or less.

17. The process of claim 1, wherein the catalyst composition further comprises at least one monodentate phosphite ligand.

18. The process of claim 1, wherein the bidentate phosphorus-containing ligand is a phosphite ligand selected from a member of the group consisting of formula XXXIII and formula XXXIV:

formula XXXIII formula XXXIV

Each R⁴²，R⁴³，R⁴⁴，R⁴⁶，R⁴⁷And R⁴⁸Independently selected from the group consisting of: h, and a primary, secondary or tertiary hydrocarbyl group of 1 to 6 carbon atoms.

19. The process of claim 18, further comprising introducing a stream comprising a crude bidentate phosphite ligand mixture comprising phosphite ligands selected from a member of the group represented by formula XXXIII and formula XXXIV:

formula XXXIII formula XXXIV

20. The process of claim 1, wherein the at least one Lewis acid comprises zinc chloride and the extractant comprises cyclohexane.