DE1260455B - Process for the production of adipic dinitrile - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

C07c

German class: 12 ο -11

Number: 1260455

File number: R38792IVb / 12o

Filing date: September 15, 1964

Open date: February 8, 1968

The present invention relates to a process for the preparation of adiponitrile by reductive Acrylonitrile dimerization.

It is known that adipic acid dinitrile is a starting material for the production of hexamethylenediamine, a component of polyamides. It is generally obtained from adipic acid which is in turn produced by oxidation of cyclohexane or cyclohexanol. However, it is of Interest in finding a process for the production of adiponitrile, in which one looks at non-cyclic compounds must serve.

Therefore, the hydrodimerization of acrylonitrile by electrochemical methods has been used of alkali amalgams in the presence of water (see British patent specification 923 250) or on tried the detour via the dicyanocyclobutane (see. USA.-Patent 3 092 654 and German Interpretation document 1104 936). In the former case, the substantial amounts of mercury required provide Carrying out the process on an industrial scale is a major disadvantage and, in the second case, requires it the production of dicyanocyclobutane and its subsequent conversion into the dinitrile an increased temperature and pressure expenditure due to hydrogenative cleavage.

The process according to the invention for the preparation of adiponitrile by reductive dimerization of acrylonitrile is characterized in that one acrylonitrile with a metal carbonyl or a Derivative of the same and molecular hydrogen and / or one under the reaction conditions Hydrogen-yielding compound in the presence of a Polymerization inhibitor and optionally a hydrogenation inhibitor heated.

Suitable metal carbonyls are in particular Fe (CO) ₅ , Fe ₂ (CO) ₉ , Fe ₃ (CO) ₁₂ , Co ₂ (CO) ₈ and Cr (CO) ₆ .

As their derivatives, one can, for example, use their hydrides or the organometallic complexes that make them up Metal carbonyls with organic unsaturated compounds, such as, for example, monoolefinic, diolefinic and acetylenic compounds, e.g., with butadiene or acrylonitrile.

Compounds which are able to give off hydrogen under the working conditions without causing disruptive side reactions are, for example, water alone and / or one or more electron donors, which are also called "Lewis bases". Such "Lewis bases" are, for example, metal hydroxides, such as alkali and alkaline earth metal hydroxides, in particular sodium and potassium hydroxide, oxides, processes for the production of
Adipic acid dinitrile

Applicant:

Rhone-Poulenc SA, Paris
Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann

and Dipl.-Chem. Dr. R. Koenigsberger,

Patent Attorneys, 8000 Munich 2, Bräuhausstr. 4th

Named as inventor:

Pierre Jean Antoine Chabardes,

Charles Camille Dominique Grard,

Lyon, Rhone;

Michel Pierre Francois Thiers,

Brignais, Rhone (France)

Claimed priority:

France of September 17, 1963 (947754),
dated October 29, 1963 (952175,
of January 14, 1964 (960 256),
dated May 8, 1964 (973 771),
dated August 19, 1964 (985 611)

such as magnesium oxide and aluminum oxide, alkali salts such as sodium carbonate, Sodium bicarbonate, borax, monosodium phosphate, monopotassium phosphate, dipotassium phosphate, amines or Derivatives of amines, such as tetraethylammonium - ρ - toluene sulfonate, N - cyanoethyl diethylamine, Ethylenediamine, o-phenanthroline, α, α'-dipyridyl, Piperidine, pyrimidine, N-cyanoethylpyrrolidine, diazabicyclooctane, tetramethylethylenediamine, trialkyl monoamines. Phosphines, arsines and stibines, especially triphenylphosphine, can also be used as "Lewis bases" and triphenylstibine. Tertiary compounds are preferably used as amine compounds Amines.

The metal carbonyls can form complexes with certain amines, and the carbonyl derivative can be used

809 507/659

I 260 455

3 4

and the amine in the reaction mixture also through the presence of a metal carbonyl and molecular replace previously formed complex. Hydrogen can only be passed through in the presence of benzene

Polymerization inhibitors can be exemplified.

wise hydroquinone, methylene blue, p-nitrosodimethyl- In the course of the reaction, various are formed

use aniline. 5 by-products, including in particular propionitrile.

As a hydrogenation inhibitor, its use in this compound that can be utilized Principle is not absolutely necessary, one can in particular from the reaction mixture by fractional distillation Use quinoline. lation separated and goes with the start of the distillation

The proportions of carbonyl compounds can exceed unreacted acrylonitrile. This Vorlaufin wide limits depending on the working conditions io fraction can fluctuate again with a new approach. If used exclusively with molecular, propionitrile is the hydrodimerization hydrogen the amount of degradation of the acrylonitrile cannot be a problem. The unreacted Used carbonyl compound relatively low carbonyl compounds can also be of the be separated and an amount of only 0.01 mol of carbonyl compound reaction mixture. reused Application per 1 mole of acrylonitrile can still be effective. Become 15. If it's a volatile carbonyl if on the other hand, if you act with or compound in an aqueous medium, recovery takes place works without using a "Lewis base", so with that of unreacted acrylonitrile. One can In order to achieve satisfactory yields, the recovered products should also be reused Amounts of metal carbonyl be greater, adjusting the content of the starting mixture all other factors being the same; generally using 20 respondents and continuously however, you can get good results without doing more work.

as 0.2 mol of carbonyl compound per 1 mol of acrylonitrile The following examples explain the invention

to use. However, it is not further disadvantageous, according to the procedure more closely, to use larger amounts of carbonyl compound than the specified amounts and in particular 25 for example the proportion of 0.2 mole per mole of acrylonitrile

exceed whatever the working conditions In an autoclave with a capacity of

are, with the excess amounts optionally 125 ecm of stainless steel, previously with nitrogen can be recovered. was flushed through, add 20 ecm of acrylonitrile,

If you work exclusively in the presence of mole- 30 250 mg hydroquinone, 3.6 g of an aqueous sodium hydrogen, the hydrogen hydroxide solution (50 g NaOH per 100 ecm of water) and under an initial pressure of about 5 to 100 at , 8 ecm iron pentacarbonyl and then direct water to be turned over. A hydrogen is preferably suitable up to a pressure of about 85 atm. Anstoffdruck of "about 25 to 50 at very good. Keyed heating the water to 15 hours under shaking material can optionally substituted by one among the work 35 to 100 ⁰ C, cooled to room temperature, laid-inert gas, for example nitrogen, the Autoclave, filtered the reaction mixture, which is a diluted. Red colored, weakly viscous suspension of solid partial

If you represent in the presence of one or more verges, and mainly wash that away bonds that are able to give off hydrogen, in the iron carbonate existing filter material (3.9 g) with 20 ecm especially in the presence of water or a gel 40 acetone.

Mixing water and a "Lewis base" works, the filtrate becomes unreacted acrylonitrile

the use of molecular hydrogen over- together with low-boiling by-products under liquid. One can then easily removed at atmospheric the vacuum of a water aspirator at 6O ⁰ C entDruck or in an autoclave under the autogenous pressure. There then remains a more viscous red color of the reaction mixture to work. However, you can 45 residue, which is distilled in vacuo. You can also use molecular hydrogen at the same time. are thus obtained 1.85 g of a fraction of bp. = 111 to _Of65 This may in certain instances, at least under a 120 ⁰ C, with a refractive index of nf = 1.4412. certain hydrogen pressure. General The residue, which consists of polymerized products, which in this case can be used before heating, weighs 4.7 g.

end hydrogen pressure between about 5 and 100 at 50. The isolated fraction is identified by its infrared spectra. trum and by hydrolysis with sulfuric acid as

If unstabilized adipic dinitrile is identified as the starting product. When acrylonitrile is used, 1.5 g of the fraction with 10 ecm of 50 weight percent mixture of 0.0005 to 0.01 mol of a polymerization sulfuric acid is added to the reaction, 1.85 g of an acid, the inhibitor of which is added per mol of acrylonitrile, is obtained . For the hydrogenation mixed melting point (150 ^° C.) with pure adipic acid inhibitor, if one is used, it is not sufficient to lower it. Addition in the same amount per mole of acrylonitrile. ". .

■ The reaction temperature can vary within wide limits Example I

fluctuate, for example from 20 to 200 ⁰ C, depending on the type of work.

conditions of employment. The reaction time can be between 60 to the 2 ecm quinoline and leads hydrogen up to 1 and 48 hours. In most cases a pressure of only about 60 at one. the best results are obtained when one gets 3.1 g of residues and 2.9 g of adipose

Temperature from 90 to 120 ° C for 12 to 20 hours nitrile.

that works. B e i s ρ i e 1 3

The conversion of acrylonitrile into adipic acid- 65 ^v

In certain cases, dinitrile can advantageously be used in countermeasures as in Example 2, but without waiting inert diluents can be carried out. Turn of hydrogen, in a nitrogen atmosphere So it can be advantageous to carry out the reaction in counter-pressure under normal pressure.

3.4 g of residues and 1.9 g of adiponitrile are then obtained.

Example 4

20 ecm of acrylonitrile, water, a nitrogenous organic base, 0.5 g of hydroquinone and 2.8 ecm of iron pentacarbonyl are placed in an autoclave with a capacity of 125 ecm made of stainless steel; Reaction conditions. ^{In the usual work-up, a fraction which boils at 96 to 105 °} C. and contains at least 90% adiponitrile is obtained under reduced pressure (0.2 mm).

water
ecm Nitrogen-containing organic base Beginner
Hydrogen pressure
at temperature
⁰ C reaction time
hours Weight of adipo
containing nitrile
fraction
G 6th
6th
2
6th 3 ecm tributylamine
2.5 g of N-cyanoethylpyrrolidine
1 g of o-phenanthroline
0.25 g diazabicyclooctane 60
0
50
0 80
80
100
110 15th
36
16
16 2
2
2.5
2.7

Example5

16 g (0.3 mol) of acrylonitrile (stabilized with traces of hydroquinone) and 25 ecm of a solution of dicobalt octacarbonyl in cyclohexane with a content of 4.34% are placed in a 100 cc flask equipped with a shaker and flushed with nitrogen. Co (= 1.08 g Co). The temperature is raised within half an hour at 64 ⁰ C (reflux) and the mixture is kept for 1 hour under reflux. 1324 Ncm ^{3 of} carbon oxide, ie 80 percent by volume of theory, corresponding to complete decomposition of the dicobalt octacarbonyl, are released, and a powdery chestnut-brown product separates out, which is separated from the cyclohexane solution by filtering under nitrogen. The filtered material is washed three times with 25 cc of petroleum ether (boiling range 55 to 6O ⁰ C), operating in the absence of air. 3.33 g of a product with a Co content of 25.2% are obtained, the infrared spectrum of which has a band corresponding to a conjugated nitrile group at 2185 cm ^-1 and bands corresponding to three carbonyl groups at 1860, 1970 and 2020 cm ^-1 it has neither a band at 2222 nor a band at 1698 cm- ¹ .

The auburn precipitate, 1 ecm quinoline, 1 g hydroquinone and 20 ecm acrylonitrile are placed in a nitrogen-flushed stainless steel autoclave with a capacity of 125 ecm, the autoclave is closed, hydrogen is injected under a pressure of about 46 atm and heated 16 hours at 6O ⁰ C.

After cooling and releasing the pressure, the contents of the autoclave are filtered under nitrogen and distilled the filtrate initially under normal pressure (12 ecm of unreacted acrylonitrile is obtained) and then under reduced pressure and obtain 0.8 g of a fraction boiling at 92 to 112 ° C / 0.25 mm, which contains 80% adipic dinitrile, the identity of which is determined by hydrolysis to adipic acid. Of the The remainder of 20% consists of 2-methylglutaric acid dinitrile.

Example 6

39.5 g of acrylonitrile, 50 ecm of benzene, 2 g of hydroquinone are placed in an autoclave with a capacity of 500 ecm, 1 g of quinoline and 12 g of acrylonitrile-cobalt carbonyl complex prepared as in Example 5, carries out the reaction under the same conditions as in the previous example and obtains 2.3 g a fraction which boils at 92 to 112 ° C / 0.25mm and contains 90% adiponitrile, the amount of recovered acrylonitrile is 32.15 g. The yield of dinitrile, based on converted acrylonitrile, is 31%.

Example 7

20 ecm of acrylonitrile, 12 ecm of water, 1 ecm of triethylamm, 0.5 g of hydroquinone and 4.2 ecm of iron pentacarbonyl are placed in a stainless steel autoclave with a capacity of 125 ecm. The contents of the autoclave are then heated, while shaking, to 100 ^° C. for 5 hours under the autogenous pressure of the reaction mixture, which at the end of the reaction reaches about 18 atm. The autoclave is cooled and relaxed. The reaction product forms two layers: the lower aqueous layer contains mainly suspended iron carbonate; the upper organic layer is brown-red in color and clear. After the solid inorganic substance has been separated off by filtration (dry weight: 2.9 g), the two layers are separated from one another. The aqueous layer is extracted with 10 ecm of ethyl ether and the ether extract is combined with the organic layer. The organic solution is then distilled on a water bath to remove the ethyl ether and acrylonitrile. By distilling the residue at 0.2 mm, 3.6 g of a ^{fraction boiling at 90 to 98 °} C. and containing 90% adiponitrile (determined by chromatography) are obtained, with 1.3 g of residue remaining.

Example 8

53 g are brought into a stainless steel autoclave with a capacity of 500 ecm Traces of hydroquinone-stabilized acrylonitrile, 25 g water, 5 ecm triethylamm and 13.9 ecm iron pentacarbonyl a. The contents of the autoclave are heated to 105 ° C. over the course of 5 hours, the pressure increasing about 15 at rises. It is cooled, relaxed and worked up in the same way as in Example 1. the Distillation of the organic layer enables the recovery of 24 g of acrylonitrile and 3.2 g Propionitrile. Then 12.7 g of a fraction boiling at 99 to 106 ° C / 0.4 mm are obtained, which 90% Contains adiponitrile; the distillation residue weighs 6.9 g.

^{Thus, with a degree of} conversion of 55%, ^a yield of 38% of adiponitrile is obtained, based on the acrylonitrile consumed.

Example 9 Example 14

In a stainless steel autoclave with a capacity of 125 ecm, 20 ecm of acrylonitrile stabilized with traces of hydroquinone, 1 ecm of water and 2 g of triethylammonium undecacarbonyl triferrate prepared according to "Journal of Chemical Society", London (1960), p. 4635, are introduced. Manpreßt at about 80 to hydrogen and heated with shaking for 15 hours at 80 ⁰ C. Fractional distillation gives 0.4 g of a 95 to 100 ° C / 0.4 mm over previous fraction, 50% of adiponitrile and 2.5 g a fraction passing over at 100 to 115 ° C / 0.4 mm which contains 90% adiponitrile in addition to residual 2-methylglutaric acid dinitrile.

Example 10

53 g of acrylonitrile (66.25 cm) stabilized with traces of hydroquinone, 19.6 g of iron pentacarbonyl (13.4 cm) and 0.3 g of methylene blue are placed in a stainless steel autoclave with a capacity of 500 cm. With a gas mixture formed from 40 percent by volume of hydrogen and 60 percent by volume of nitrogen, a pressure of about 50 atm is set and the mixture is heated with shaking for 16 hours at 113 ° C. After cooling and releasing the pressure, the volatile fractions are removed by fractional distillation of the reaction mixture. One gets in this case 55 cc of a forward travel, of below 85 ° C / 760mm passes, and 7.2 cc (5.7 g) of a fraction of bp. _0j35 = 95 and 115 ⁰ C, which contains 88% adiponitrile. The first runnings, which after determination by vapor phase chromatography contain 28.16 g of unreacted acrylonitrile and 16.5 g of unreacted iron pentacarbonyl, can be reused for a later operation.

Example 11

In a stainless steel autoclave with a capacity of 125 cc brings mixing 20 cc of acrylonitrile, 12 cc of water, 4.2 cc of iron pentacarbonyl, 0.5 g of hydroquinone and 2 g of triphenylphosphine, shaken for 15 hours at 100 ⁰ C under the autogenous pressure of the Reaction mixture, then cools and relaxes. The reaction product forms two rails which, as in Example 7, are separated from one another and worked up. Distillation gives 1.15 g of a fraction which boils at 98 to 110 ° C./0.3 mm and contains 85% adiponitrile.

Example 12

The procedure is as in Example 11, but using the following proportions of reactants: 20 ecm acrylonitrile, 4 ecm water, 4.2 ecm Iron pentacarbonyl, 0.5 g hydroquinone and 3 g triphenylstibine and is finally obtained by distillation at 98 to 110 ° C / 0.3mm 1.6 g of a fraction containing 1.23 g of adiponitrile.

Example 13

The procedure is as in Example 11, but the following amounts of reactants are used: 1 cm acrylonitrile, 6.4 cm water, 3.5 g dipotassium phosphate (K ₂ HPO ₄ ), 2.8 cm iron pentacarbonyl and 0.5 g hydroquinone and receives 2 , 7 g of a fraction boiling at 90 to 110 ° C / 0.3 mm and containing 2 g of adiponitrile.

A 51 capacity stainless steel autoclave equipped with a side shaker is charged with 1060 grams (20 moles) of acrylonitrile, 132 grams of distilled water, and 260 grams (1.32 moles) of iron pentacarbonyl. ^{The reactants are heated up to 130 °} C. under the autogenous pressure and this temperature is maintained for 7 hours 15 minutes, a maximum pressure of about 22 atm being reached. It is cooled, and unreacted acrylonitrile and iron pentacarbonyl, which is used again directly in a subsequent operation, are removed from the reaction mixture by heating in vacuo up to 100.degree. It is then filtered, the filter material slurried twice in 200 ecm boiling acetone and then washed with acetone. The acetone fractions are then combined with the filtrate and concentrated by evaporation. The concentrate obtained in this way is distilled in vacuo at 0.2 mm, and 33.1 g of a ^{fraction which passes over at 100 to HO 0} C and contains% adiponitrile are obtained. In the course of this experiment 50.6 g of acrylonitrile are consumed. The yield of adiponitrile is therefore 52.5%

Claims (8)

Patent claims: 1. Process for the preparation of adipic acid dinitrile by reductive dimerization of acrylonitrile, characterized in that acrylonitrile with a metal carbonyl or a derivative of the same and molecular hydrogen and / or a compound which yields hydrogen under the reaction conditions in Heated in the presence of a polymerization inhibitor and optionally a hydrogenation inhibitor. 2. The method according to claim 1, characterized in that one of acrylonitrile, a metal carbonyl and a polymerization inhibitor in the presence of molecular Hydrogen is heated, optionally in the presence of an inert liquid diluent is working. 3. The method according to claim 1 and 2, characterized in that when using molecular hydrogen under a hydrogen pressure of about 5 to 100 at, preferably about 25 to 50 at, works. 4. The method according to claim 1, characterized in that there is used as the hydrogen-yielding compound a "Lewis base" is used. 5. The method according to claim 1 to 4, characterized in that 0.0005 to 0.01 mol Polymerization inhibitor is added per mole of acrylonitrile. 6. The method according to claim 1 to 5, characterized in that the metal carbonyl Iron pentacarbonyl used. 7. The method according to claim 1 to 6, characterized in that in the presence of a Complex compound of a metal carbonyl and an unsaturated organic compound works. 8. The method according to claim 1 to 7, characterized in that the reaction ^{temperature 20 to 200 0} C, preferably 90 to 120 ⁰ C, is. 809 507/659 1.68 © Bundesdruckerei Berlin