HK1099274B - Process for the preparation of 1,1,1,3,3-pentafluoropropane and 1,1,1,2,3-pentafluoropropane - Google Patents

Description

Process for the preparation of 1, 1, 1,3, 3-pentafluoropropane and 1, 1, 1, 2, 3-pentafluoropropane

Technical Field

The present invention relates to the synthesis of 1, 1, 1,3, 3-pentafluoropropane and 1, 1, 1, 2, 3-pentafluoropropane.

Background

Various chlorine-containing halocarbons are believed to be detrimental to the earth's ozone layer. Materials with low ozone depletion potential that can be used as effective alternatives are being developed worldwide. For example, hydrofluorocarbon 1, 1, 1, 2-tetrafluoroethane (HFC-134a) is being used as a replacement for dichlorodifluoromethane (CFC-12) in refrigeration systems. There is a need for a process for the preparation of halogenated hydrocarbons which provides little or no chlorine. The production of hydrofluorocarbons (i.e., compounds containing only carbon, hydrogen, and fluorine) has been the subject of considerable interest to provide environmentally desirable products for use as solvents, blowing agents, refrigerants, cleaning agents, aerosol propellants, heat transfer media, dielectrics, fire extinguishing agents, and power cycle working fluids. For example, 1, 1, 1,3, 3-pentafluoropropane may be used as a blowing agent, and 1, 1, 1, 2, 3-pentafluoropropane may be used as a refrigerant and as an intermediate for producing fluoroolefins.

Summary of The Invention

The present invention provides a process for the preparation of 1, 1, 1,3, 3-pentafluoropropane (HFC-245fa) and 1, 1, 1, 2, 3-pentafluoropropane (HFC-245 eb). The method comprises (a) reacting Hydrogen Fluoride (HF), chlorine (Cl)₂) With at least one compound of the formula CX₃A halopropene of formula CCl ═ CClX, wherein each X is independently selected from F and Cl, to produce a reaction product comprising CF₃CCl₂CClF₂And CF₃CClFCCl₂F, wherein said CF₃CCl₂CClF₂And CF₃CClFCCl₂F is formed in the presence of a chlorofluorination catalyst comprising at least one composition selected from the group consisting of: (i) containing ZnCr₂O₄And crystalline alpha-chromium oxide; (ii) a composition comprising a zinc halide and alpha-chromium oxide; and (iii) a composition of (i) or (ii) that has been treated with a fluorinating agent (e.g., anhydrous hydrogen fluoride); (b) CF to be generated in (a)₃CCl₂CClF₂And CF₃CClFCCl₂F and hydrogen (H)₂) Optionally in the presence of HF, to form a catalyst comprising CF₃CH₂CHF₂And CF₃CHFCH₂The product of F; and (c) recovering CF from the product formed in (b)₃CH₂CHF₂And CF₃CHFCH₂F。

Detailed Description

The present invention provides for the preparation of CF₃CH₂CHF₂(HFC-245fa) and CF₃CHFCH₂F (HFC-245 eb). HFC-245fa and HFC-245eb can be recovered as separate products and/or as one or more mixtures of the two products.

In step (a) of the process of the present invention, one or more halopropene compound(s) CX are added₃CCl ═ CClX, where each X is independently selected from F and Cl, and chlorine (Cl)₂) And Hydrogen Fluoride (HF) to form a gas mixture comprising CF₃CCl₂CClF₂(CFC-215aa) and CF₃CClFCCl₂F (CFC-215 bb). Thus, the present invention provides for the preparation of CF from readily available starting materials₃CCl₂CClF₂(CFC-215aa) and CF₃CClFCCl₂F (CFC-215 bb).

Suitable feedstocks for the process of the present invention include E-and Z-CF₃CCl＝CClF(CFC-1214xb)、CF₃CCl＝CCl₂(CFC-1213xa)、CClF₂CCl＝CCl₂(CFC-1212xa)、CCl₂FCCl＝CCl₂(CFC-1211xa) and CCl₃CCl＝CCl₂(hexachloropropene, HCP) or mixtures thereof.

The preferred starting material for the process of the present invention is CF due to its ready availability₃CCl＝CCl₂(CFC-1213xa) and CCl₃CCl-CCl₂(hexachloropropene, HCP).

Preferably, HF and Cl₂With halopropenes CX₃The reaction of CCl ═ CClX is carried out in the gas phase in a heated tubular reactor. A variety of reactor configurations are possible, including vertical and horizontal reactor orientations, and different ways of contacting the halopropene starting material(s) with HF and chlorine. Preferably, the HF and chlorine are substantially anhydrous.

In one embodiment of step (a), the halopropene starting material(s) are fed to a reactor in contact with the chlorofluorination catalyst. The halopropene starting material(s) may be initially vaporized and fed as a gas to the first reaction zone.

In another embodiment of step (a), the halopropene starting material(s) may be contacted with HF in a pre-reactor. The prereactor may be empty (i.e. unfilled), but is preferably filled with a suitable packing, for example Monel^TMOr Hastelloy^TMNickel alloy shavings or felts, or otherwise inert to HCl and HF and rendering CX₃CCl is a material that can be efficiently mixed with HF vapor.

If the halopropene starting material(s) is/are fed as a liquid to the prereactor, the prereactor is preferably a vertical reactorOf (b) wherein CX₃CCl ═ CClX enters the top of the reactor, and preheated HF vapor is introduced at the bottom of the reactor.

For the pre-reactor, suitable temperatures are in the range of about 80 ℃ to about 250 ℃, preferably about 100 ℃ to about 200 ℃. Under these conditions, for example, hexachloropropene is converted into a mixture containing predominantly CFC-1213 xa. The feed rate of the feedstock is determined by the length and diameter of the reactor, the temperature and the degree of fluorination desired in the pre-reactor. Slower feed rates at a given temperature will increase contact time and tend to increase the amount of conversion of the starting material, as well as increase the degree of fluorination of the product.

The term "degree of fluorination" means CX₃CCl ═ the extent to which fluorine atoms in the CClX starting material replaced chlorine substituents. For example, CF₃CCl ═ CClF stands for ratio CClF₂CCl＝CCl₂High degree of fluorination, and CF₃CCl₂CF₃Representative ratio CClF₂CCl₂CF₃A high degree of fluorination.

The molar ratio of HF fed to the pre-reactor or to the reaction zone of step (a) to halopropene starting material fed in step (a) is typically from about stoichiometric to about 50: 1. The stoichiometric ratio depends on the average degree of fluorination of the halopropene starting material and is typically based on C₃Cl₃F₅Is performed. For example, if the halopropene is HCP, the stoichiometric ratio of HF to HCP is 5: 1; if the halopropene is CFC-1213xa, the stoichiometric ratio of HF to CFC-1213xa is 2: 1. Preferably, the ratio of HF to halopropene starting material(s) is the stoichiometric ratio of HF to halopropene (based on C)₃Cl₃F₅From about 2 times to about 30: 1. Higher ratios of HF to halopropene are not particularly advantageous. Lower ratios result in C₃Cl₃F₅The yield of the isomer decreases.

If the halopropene starting material(s) are contacted with HF in the pre-reactor, the effluent from the pre-reactor is contacted with chlorine in the presence of a chlorofluorination catalyst.

In step (b)In another embodiment of step (a), the halopropene starting material(s) may be reacted with Cl₂And HF in a pre-reactor. The prereactor may be empty (i.e. unfilled), but is preferably filled with a suitable packing, for example Monel^TMOr Hastelloy^TMNickel alloy shavings or felts, activated carbon, or otherwise for HCl, HF and Cl₂Is inert and makes CX₃CCl ═ CClX, HF and Cl₂Materials capable of being efficiently mixed.

At least a portion of the halopropene starting material(s) is/are typically reacted with Cl₂And HF in a prereactor by reacting Cl₂Addition to an olefinic bond to form a saturated halopropane, and substituting at least a portion of the Cl substituents in the halopropane and/or halopropene with F. In this embodiment of the invention, a suitable temperature for the pre-reactor is from about 80 ℃ to about 250 ℃, preferably from about 100 ℃ to about 200 ℃. The high temperature results in more halopropene entering the reactor being converted to saturated products and a higher degree of halogenation and fluorination in the pre-reactor product.

The term "degree of halogenation" refers to the extent to which hydrogen substituents in a halocarbon have been replaced by halogen and carbon-carbon double bonds have been saturated with halogen. For example, CF₃CCl₂CClF₂Has a ratio of CF₃CCl＝CCl₂High degree of halogenation. Furthermore, CF₃CCl₂CClF₂Has a ratio of CF₃CHClCClF₂High degree of halogenation.

Cl₂The molar ratio to halopropene starting material(s) is generally from about 1: 1 to about 10: 1, preferably from about 1: 1 to about 5: 1. Feeding Cl in a ratio of less than 1: 1₂Will result in significant amounts of unsaturated materials and hydrogen containing by-products in the reactor effluent.

In a preferred embodiment of step (a), the halopropene starting material(s) are vaporized, preferably in the presence of HF, and reacted with HF and Cl₂In a pre-reactor and then with a chlorofluorination catalyst. If preferred amounts of HF and Cl are used₂Feeding into a prereactor, when the effluent of the prereactor is reacted with chlorofluoroWhen the catalyst is contacted, no additional HF and Cl are required in the reaction zone₂。

For the catalytic chlorofluorination of halopropene starting materials and/or products formed therefrom in pre-reactors, suitable temperatures are from about 200 ℃ to about 400 ℃, preferably from about 250 ℃ to about 350 ℃, depending on the desired conversion of the starting materials and the activity of the catalyst. Reactor temperatures in excess of about 350 ℃ may result in products having a degree of fluorination greater than 5. In other words, at higher temperatures, substantial amounts of chloropropanes (e.g., CF) containing 6 or more fluorine substituents can be formed₃CCl₂CF₃Or CF₃CClFCClF₂). Temperatures below about 240 c result in the formation of substantial amounts of products having a degree of fluorination below 5 (i.e., underfluorinated products).

For gas phase embodiments of the present invention, suitable reactor pressures may range from about 1 to about 30 atmospheres. Reactor pressures of from about 5 atmospheres to about 20 atmospheres can be advantageously employed to assist in separating HCl from other reaction products in step (b) of the process of the present invention.

The chlorofluorination catalyst used in the process of the invention preferably comprises ZnCr₂O₄(Zinc chromium oxide) and crystalline alpha-Cr₂O₃(alpha-chromium oxide) or by treating said composition comprising ZnCr with a fluorinating agent₂O₄(Zinc chromium oxide) and alpha-Cr₂O₃(alpha-chromium oxide) in the presence of a catalyst. The amount of zinc relative to the total amount of chromium and zinc in these compositions is preferably from about 1 atomic% to about 25 atomic%.

It is noteworthy that it contains ZnCr₂O₄(zinc chromite) and crystalline alpha-chromium oxide, wherein ZnCr is₂O₄Comprises from about 10 atomic% to about 67 atomic% of the chromium in the composition and at least about 70 atomic% of the zinc in the composition, and wherein at least about 90 atomic% of the chromium present in the composition as chromium oxide is as ZnCr₂O₄Or crystalline alpha-chromium oxide; it is also worth noting thatBy treating such ZnCr-containing compositions with fluorinating agents₂O₄And crystalline alpha-chromium oxide. It is also noteworthy that such a composition contains ZnCr₂O₄And crystalline alpha-chromium oxide, wherein the ZnCr is₂O₄Comprising from about 20 atomic% to about 50 atomic% chromium in the composition. It is also noteworthy that such a composition contains ZnCr₂O₄And crystalline alpha-chromium oxide, wherein the ZnCr is₂O₄Contains at least about 90 atomic percent of the zinc in the composition. Also of note are chromium-containing catalyst compositions comprising zinc chromite (zinc chloride) and crystalline alpha-chromium oxide in which greater than 95 atomic percent of the chromium not present as zinc chromite (zinc chloride) is present as crystalline alpha-chromium oxide. It is also noteworthy that it consists essentially of ZnCr₂O₄(zinc chromite) and crystalline alpha-chromium oxide.

These compositions can be prepared, for example, by a co-precipitation method followed by calcination.

In a typical co-precipitation process, an aqueous solution of a zinc salt and a chromium (III) salt is prepared. The relative concentrations of the zinc salt and chromium (III) salt in the aqueous solution are determined by the overall atomic percentage of zinc relative to chromium that is required in the final catalyst. Thus, the concentration of zinc in the aqueous solution is from about 1 mole% to about 25 mole% of the total concentration of zinc and chromium in the solution. The concentration of chromium (III) in the aqueous solution is generally 0.3 to 3 mol/l, preferably 0.75 to 1.5 mol/l. Although different chromium (III) salts may be employed, for the preparation of the aqueous solution chromium (III) nitrate or its hydrated forms, such as [ Cr (NO)₃)₃(H₂O)₉]The most preferred chromium (III) salts.

Although different zinc salts may be used to prepare the aqueous solution, preferred zinc salts for use in preparing the catalyst for use in the process of the invention include zinc (II) nitrate and hydrated forms thereof such as [ Zn (NO)₃)₂(H₂O)₆]。

The aqueous solution of chromium (III) and zinc salts may then be evaporated under vacuum or at elevated temperature to obtain a solid, which is then calcined.

The aqueous solutions of the chromium (III) and zinc salts are preferably treated with a base such as ammonium hydroxide (ammonia) to precipitate the zinc and chromium as hydroxides. Alkali metal containing bases such as sodium or alkali hydroxides or carbonates may be used but are not preferred. The addition of ammonia to the aqueous solution of the chromium (III) and zinc salts is generally carried out gradually over a period of from 1 to 12 hours. The pH of the solution was monitored during the addition of the base. The final pH is generally from 6.0 to 11.0, preferably from about 7.5 to about 9.0, and most preferably from about 8.0 to about 8.7. The precipitation of the mixture of zinc hydroxide and chromium hydroxide is generally carried out at a temperature of from about 15 ℃ to about 60 ℃, preferably from about 20 ℃ to about 40 ℃. After the addition of ammonia, the mixture is typically stirred for up to 24 hours. Precipitated chromium hydroxide and zinc hydroxide as ZnCr₂O₄And precursors of alpha-chromium oxide.

After the precipitation of the mixture of zinc hydroxide and chromium hydroxide is complete, the mixture is dried by evaporation. This can be done by heating the mixture at a suitable temperature in an open pan or on a hot plate or steam bath or in an oven or furnace. Suitable temperatures include temperatures of about 60 ℃ to about 130 ℃ (e.g., about 100 ℃ to about 120 ℃). Alternatively, the drying step may be carried out under vacuum using, for example, a rotary evaporator.

Optionally, the precipitated zinc and chromium hydroxide mixture may be collected and, if desired, washed with deionized water prior to drying. Preferably, the precipitated zinc and chromium hydroxide mixture is not washed prior to the drying step.

After drying the zinc and chromium hydroxide mixture, the nitrate is decomposed by heating the solid at about 250 ℃ to about 350 ℃. The resulting solid is then calcined at a temperature of from about 400 ℃ to about 1000 ℃, preferably from about 400 ℃ to about 900 ℃.

Further information on the zinc and chromium compositions used in the present invention is provided in U.S. patent application 60/511,353[ CL2244 US PRV ], filed on 14/10/2003, which is incorporated herein by reference in its entirety (see also the corresponding international application PCT/US2004____ /).

The calcined zinc chromite (zinc chloride)/α -chromium oxide compositions of the present invention may be pressed into a variety of different shapes such as pellets for use in a packed reactor. It can also be used in powder form.

The calcined composition is typically pretreated with a fluorinating agent prior to use as a catalyst for changing the fluorine content of halogenated carbon compounds. The fluorinating agent is typically HF, although other fluorinating agents such as sulfur tetrafluoride, carbonyl fluoride, and fluorinated carbon compounds such as trichlorofluoromethane, dichlorodifluoromethane, fluorodifluoromethane, trifluoromethane, or 1, 1, 2-trichlorotrifluoroethane may also be used. This pretreatment can be carried out, for example, by: the catalyst is placed in a suitable vessel, which may be the reactor to be used to carry out the process of the invention, and the dried, calcined catalyst is then passed with HF to partially saturate the catalyst with HF. This is conveniently done by passing HF over the catalyst at a temperature of, for example, about 200 ℃ to about 450 ℃ for about 0.1 to about 10 hours. Nevertheless, this pretreatment is not necessary.

Other catalysts suitable for the chlorofluorination of step (a) are compositions comprising zinc halide and alpha-chromium oxide and compositions obtained by treating said compositions comprising zinc halide and alpha-chromium oxide with a fluorinating agent. Examples of such catalysts are disclosed in U.S. patent 3,878,257. The amount of zinc relative to the total amount of chromium and zinc in these compositions is preferably from about 0.1 atomic% to about 25 atomic%; more preferably from about 2 atomic% to about 10 atomic%. Of note are compositions wherein the zinc halide is supported on a support comprising alpha-chromium oxide. Preferably, the alpha-chromium oxide is prepared according to U.S. support 5,036,036. The pretreatment with the fluorinating agent can be carried out in the manner described above for the calcined zinc chromite (zinc chloride)/α -chromium oxide composition.

The compound produced in the chlorofluorination process of step (a) includes the halopropane CF₃CCl₂CClF₂(CFC-215aa) and CF₃CClFCCl₂F(CFC-215bb)。

Halopropane by-products having a higher degree of fluorination than CFC-215aa and CFC-215bb that may be produced in step (a) include CF₃CCl₂CF₃(CFC-216aa)、CF₃CClFCClF₂(CFC-216ba)、CF₃CF₂CCl₂F(CFC-216cb)、CF₃CClFCF₃(CFC-217ba) and CF₃CHClCF₃(HCFC-226da)。

Halopropane by-products having a lower degree of fluorination than CFC-215aa and CFC-215bb that may be produced in step (a) include CF₃CCl₂CCl₂F(HCFC-214ab)。

Halopropene byproducts which may be formed in step (a) include CF₃CCl＝CF₂(CFC-1215xc), E-and Z-CF₃CCl ═ CClF (CFC-1214xb) and CF₃CCl＝CCl₂(CFC-1213xa)。

Comprising CF₃CCl₂CClF₂(CFC-215aa) and CF₃CClFCCl₂The effluent from step (a) of F (CFC-215bb) and optionally HF is generally separated from the following components: containing HCl, Cl₂A low-boiling component of HF comprising C₃ClF₇And C₃Cl₂F₆Over-fluorinated product of isomers, comprising C₃ClF₅And C₃Cl₂F₄An isomeric hypohalogenated (under-halogenated) component, and a composition comprising C₃Cl₄F₄Isomers and underfluorinated (underfluorinated) components of CFC-1213 xa.

In another embodiment of the invention, the reactor effluent of step (a) is delivered to a distillation column where HCl and any HCl azeotropes are removed from the top of the column and higher boiling components are removed from the bottom of the column. The product recovered from the bottom of the first distillation column is then delivered to a second distillation column in which HF, Cl₂、CF₃CCl₂CF₃(CFC-216aa)、CF₃CClFCClF₂(CFC-216ba)、CF₃CF₂CCl₂F(CFC-216cb)、CF₃CClFCF₃(CFC-217ba) and CF₃CHClCF₃(HCFC-226da) and its HF azeotrope are recovered at the top of the second distillation column, and CFC-215aa and CFC-215bb, as well as any remaining HF and high boiling components, are withdrawn from the bottom of the column. The product recovered from the bottom of the second distillation column may then be delivered to another distillation column to separate the under-fluorinated byproducts and intermediates and to isolate CFC-215aa and CFC-215 bb.

Optionally, after distilling and separating the HCl from the reactor effluent of step (a), the resulting mixture of HF and halopropanes and halopropenes can be delivered to a decanter controlled at a suitable temperature to allow the HF-rich phase to separate from the organic-rich phase. The organic-rich phase may then be distilled to separate out CFC-215aa and CFC-215 bb. The HF-rich phase may then be recycled to the reactor of step (a), optionally after removal of any organic components by distillation. In CFC-215aa/CFC-215bb separation schemes where HF is present, the decantation step may be used at other points.

In one embodiment of the present invention, the under-fluorinated and under-halogenated components (e.g., CFC-214ab, CFC-1212xb, and CFC-1213xa) are returned to step (a).

In another embodiment of the present invention, the CFC-216aa, CFC-216ba and HCFC-226da byproducts are reacted with HF, or HF and Cl if HCFC-226da is present₂Further reacted to form CF₃CClFCF₃(CFC-217ba), which in turn can be converted to Hexafluoropropylene (HFP), as described in U.S. Pat. Nos. 5,068,472 and 5,057,634.

In another embodiment of the present invention, HCFC-226da, CFC-216aa, CFC-216ba, CFC-217ba and by-products are reacted with hydrogen (H)₂) Further reacted to produce 1, 1, 1,3, 3, 3-hexafluoropropane (HFC-236fa), 1, 1, 1, 2, 3, 3-hexafluoropropane (HFC-236ea) and 1, 1, 1, 2, 3, 33-heptafluoropropane (HFC-227ea), as in U.S. patent application 60/511,355[ CL2246US PRV ] filed on 14.10.2003](see also corresponding International application PCT/US 2004/____).

In step (b) of the process of the present invention, the CF formed in step (a) is₃CCl₂CClF₂(CFC-215aa) and CF₃CClFCCl₂F (CFC-215bb) with hydrogen (H)₂) Optionally in the presence of HF.

In one embodiment of step (b), a mixture comprising CFC-215aa and CFC-215bb is reacted with hydrogen (H) in the vapor phase₂) And optionally HF together into a reactor made of nickel, iron, titanium, or alloys thereof as described in U.S. patent 6,540,933; the teachings of this publication are incorporated herein by reference. Reaction vessels of these materials, optionally filled with metal, in suitable form (e.g. metal tubes) may also be used. When referring to alloys, this refers to nickel alloys containing 1 to 99.9% by weight nickel, iron alloys containing 0.2 to 99.8% by weight iron, and titanium alloys containing 72 to 99.8% by weight titanium. Notably, an empty (i.e. unfilled) reaction vessel made of nickel or a nickel alloy, for example a nickel alloy containing 40-80% nickel, such as Inconel, is used^TM600 nickel alloy, Hastelloy^TMC617 nickel alloy or Hastelloy^TMC276 nickel alloy.

When used for packing, the metal or metal alloy may be in the form of particles or formed shapes such as perforated plates, rings, wires, screens, chips, tubes, beads, tissues or fluff.

In this embodiment, the temperature of the reaction may be from about 350 ℃ to about 600 ℃, preferably at least about 450 ℃.

The molar ratio of hydrogen to the CFC-215aa/CFC-215bb mixture fed to the reaction zone should be about 0.1 mole H₂Per mole of CFC-215 isomer to about 60 moles of H₂Per mole of CFC-215 isomer, more preferably from about 0.4 to 10 moles of H₂Per mole of CFC-215 isomer.

In another embodiment of step (b), the contacting of hydrogen with CFC-215aa and CFC-215bb produced in step (a), and optionally HF, is conducted in the presence of a hydrogenation catalyst. Hydrogenation catalysts suitable for use in this embodiment include catalysts comprising at least one metal selected from the group consisting of: rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, and platinum. The catalytic metal component is typically supported on a support such as carbon or graphite or a metal oxide, fluorinated metal oxide or metal fluoride wherein the support metal is selected from magnesium, aluminium, titanium, vanadium, chromium, iron and lanthanum. Of note are carbon-supported catalysts in which the carbon support has been washed with acid and has an ash content of less than about 0.1% by weight. Hydrogenation catalysts supported on low ash carbon are described in U.S. patent 5,136,113, the teachings of which are incorporated herein by reference.

Supported metal catalysts can be prepared by conventional methods known in the art, for example by impregnating the support with a soluble salt of the catalytic metal (e.g., palladium chloride or rhodium nitrate), as described by Satterfield on page 95 of Heterogenous Catalysis in Industrial Practice, 2 nd edition (McGraw-Hill, New York, 1991). The concentration of catalytic metal on the support is typically from about 0.1 wt% to about 5 wt% of the catalyst.

The relative amount of hydrogen contacted with CFC-215aa and CFC-215bb in the presence of a hydrogenation catalyst is typically about 0.5 moles of H₂Per mole trichloropentafluoropropane isomer-about 10 moles H₂Per mole of trichloropentafluoropropane isomer, preferably about 3 moles of H₂Per mole trichloropentafluoropropane isomer-about 8 moles of H₂Per mole of trichloropentafluoropropane isomer.

For catalytic hydrogenation, suitable temperatures are generally from about 100 ℃ to about 350 ℃, preferably from about 125 ℃ to about 300 ℃. Temperatures above about 350 ℃ tend to result in defluorination side reactions; temperatures below about 125 deg.C will result in C₃Cl₃F₅The substitution of H for Cl in the starting material is incomplete. The reaction is usually carried out under normal pressure or superatmospheric pressure.

In the reaction zone of step (b)The effluent typically comprises HCl, unreacted hydrogen, CF₃CH₂CHF₂(HFC-245fa)、CF₃CHFCH₂F (HFC-245eb), low boiling by-products (generally including CF)₃CH＝CF₂(HFC-1225zc), E-and Z-CF₃CH＝CHF(HFC-1234ze)、CF₃CF＝CH₂(HFC-1234yf)、CF₃CH₂CF₃(HFC-236fa)、CF₃CHFCH₃(HFC-254eb) and/or CF₃CH₂CH₃(HFC-263fb)) and high boiling by-products and intermediates, typically including CF₃CH₂CH₂Cl(HCFC-253fb)、CF₃CHFCH₂Cl(HCFC-244eb)、CF₃CClFCH₂F(HCFC-235bb)、CF₃CHClCHF₂(HCFC-235da)、CF₃CHClCClF₂(HCFC-225da) and/or CF₃CClFCHClF (HCFC-225ba diastereomer)) and any HF carried over from step (a) or (b).

In step (c), the desired product is recovered. The reactor product of step (b) may be delivered to a separation unit for recovery of CF₃CH₂CHF₂And CF₃CHFCH₂F, which are recovered individually or as a mixture.

Partially chlorinated byproducts, such as HCFC-235da, HCFC-235bb, HCFC-225ba and HCFC-225da may be recovered and returned to step (b).

The reactor, distillation column and its associated feed lines, effluent lines and associated equipment used to carry out the process of the present invention should be constructed of materials resistant to hydrogen fluoride and hydrogen chloride. Typical materials of construction well known in the fluorination art include stainless steels, particularly austenitic stainless steels, well known high nickel alloys such as Monel^TMNickel-copper alloy, Hastelloy^TMNickel-based alloy and Inconel^TMNickel-chromium alloys, and copper-lined steels.

The following specific embodiments are illustrative only and do not limit the remainder of the disclosure in any way.

Examples

Description of the symbols

214ab is CF₃CCl₂CCl₂F215 aa is CF₃CCl₂CClF₂

215bb is CCl₂FCClFCF₃216aa is CF₃CCl₂CF₃

216ba is CClF₂CClFCF₃217ba is CF₃CClFCF₃

225ba is CF₃CClFCHClF 225da is CF₃CHClCClF₂

226da is CF₃CHClCF₃235bb is CF₃CClFCH₂F

235 is C₃H₂ClF₅235da is CF₃CHClCHF₂

235fa is CF₃CH₂CClF₂236fa is CF₃CH₂CF₃

245eb is CF₃CHFCH₂F245 fa is CF₃CH₂CHF₂

254eb is CF₃CHFCH₃263fb is CF₃CH₂CH₃

1213xa is CF₃CCl＝CCl₂1215xc is CF₃CCl＝CF₂

1224 is C₃HClF₄1225zc is CF₃CH＝CF₂

Preparation of the catalyst

Comparative preparation example 1

Preparation of 100% chromium catalyst (400 ℃ C.)

To 400g Cr (NO)₃)₃[9(H₂O)](1.0 moles) to a solution in 1000mL of deionized water 477mL of 7.4M aqueous ammonia was added dropwise, causing the pH to rise to about 8.5. The slurry was stirred at room temperature overnight. After adjusting the pH to 8.5 again with ammonia, the mixture was poured into an evaporation dish and dried in air at 120 ℃. The dried solid was then calcined in air at 400 ℃; the resulting solid weighed 61.15 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 28.2g (20mL) was used in comparative example 3.

Comparative preparation example 2

Preparation of 2% Zinc on alumina catalyst

Alumina (4.90 mol, Harshaw 3945, dried at 110 ℃) was added to 20.85g ZnCl₂(0.153 mol) was dissolved in 460mL of distilled water. Water was evaporated from the mixture under stirring and then dried at 110 ℃ for 3 days. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 21.1g (30mL) was used in comparative example 1.

Preparation of example 1

Preparation of 2% Zinc chloride Supported on chromium oxide

1.20g of ZnCl in a 125mm X65 mm glass dish₂(8.81mmol) in 60mL deionized water with 60.00g (0.357 mol) of 12-20 mesh Cr₂O₃And (6) processing. The dish was placed on a warm plate and the slurry was allowed to dry with occasional stirring. The resulting solid was then dried at 130 ℃ overnight; the resulting solid weighed 60.42 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 41.5g (30mL) was used in example 9.

Preparation of example 2

Preparation of 95% chromium/5% Zinc catalyst (450 ℃ C.)

Preparation of 380.14g Cr (NO)₃)₃[9(H₂O)](0.950 mol) and 14.87gZn (NO)₃)₂[6(H₂O)](0.050 moles) in 1000mL of deionized water. 450mL of 7.4M aqueous ammonium hydroxide was added to the solution over 1 hour; the pH increased from 1.7 to pH 8.4. The slurry was stirred at room temperature overnight and then dried in an oven at 120 ℃ in the presence of air. The dried solid was then calcined in air at 450 ℃ for 20 hours; the resulting solid weighed 76.72 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 38.5g (25mL) was used in example 13.

Preparation of example 3

Preparation of 90% chromium/10% Zinc catalyst (900 deg.C)

Preparation of 360.13g Cr (NO)₃)₃[9(H₂O)](0.900 mol) and 29.75g Zn (NO)₃)₂[6(H₂O)](0.100 moles) in 1000mL of deionized water. 450mL of 7.4M aqueous ammonium hydroxide was added to the solution over 1.4 hours; the pH increased from 1.9 to pH 8.4. The slurry was stirred at room temperature overnight and then dried in the presence of air at 120 ℃. The dried solid was then calcined in air at 900 ℃ for 20 hours; the resulting solid weighed 75.42 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 42.3g (25mL) was used in examples 4, 5 and 6.

Preparation of example 4

Preparation of 95% chromium/5% Zinc catalyst (900 ℃ C.)

Preparation of 380.14g Cr (NO)₃)₃[9(H₂O)](0.950 mol) and 14.87gZn (NO)₃)₂[6(H₂O)](0.050 moles) in 1000mL of deionized water. 450mL of 7.4M aqueous ammonium hydroxide was added to the solution over 1 hour; the pH increased from 1.7 to pH 8.4. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. Then will dryThe dried solid was calcined in air at 900 ℃ for 20 hours; the resulting solid weighed 70.06 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 25.3g (14mL) was used in examples 1 and 2.

Preparation of example 5

Preparation of 98% chromium/2% Zinc catalyst (900 ℃ C.)

Preparation of 392.15g Cr (NO)₃)₃[9(H₂O)](0.980 moles) and 5.94gZn (NO)₃)₂[6(H₂O)](0.020 moles) in 1000mL of deionized water. 450mL of 7.4M aqueous ammonium hydroxide was added to the solution over 0.58 hours; the pH increased from 1.67 to pH 8.35. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. The dried solid was then calcined in air at 900 ℃ for 21 hours; the resulting solid weighed 66.00 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 44.9g (23mL) was used in examples 7 and 8.

Preparation of example 6

Preparation of 10% Zinc chloride Supported on chromium oxide

6.0g of ZnCl in a 170mm by 90mm glass dish₂(44mmol) in 300mL deionized water with 60.00g (0.357 mol) of 12-20 mesh Cr₂O₃And (6) processing. The dish was placed on a warm plate and the slurry was allowed to dry with occasional stirring. The resulting solid was then dried at 130 ℃ overnight; the resulting solid weighed 65.02 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 37.5g (25mL) was used in examples 10 and 11.

Preparation of example 7

Preparation of 98.1% chromium/1.9% Zinc catalyst (550 deg.C)

516.46g Cr (NO) were prepared in a 1L beaker placed on a hot plate₃)₃[9(H₂O)](1.29 mol) and 7.31g Zn (NO)₃)₂[6(H₂O)](0.0246 mol) in 500mL of distilled water. The mixture was then transferred to Pyrex^TMIn the container, the container is placed in an oven. The vessel was heated from room temperature to 125 ℃ at a rate of 10 ℃/min and then held at 125 ℃ for 6 hours. The vessel was heated from 125 ℃ to 350 ℃ at a rate of 1 ℃/min and then held at 350 ℃ for 6 hours. The vessel was heated from 350 ℃ to 550 ℃ at a rate of 1 ℃/min and then held at 550 ℃ for 24 hours. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 29.9g (20mL) was used in example 12.

Preparation of example 8

Preparation of 80% chromium/20% Zinc catalyst (900 deg.C)

Preparation of 320.12g Cr (NO)₃)₃[9(H₂O)](0.800 mol) and 59.49gZn (NO)₃)₂[6(H₂O)](0.200 moles) in 1000mL of deionized water. 450mL of 7.4M aqueous ammonium hydroxide was added to the solution over 1 hour; the pH increased from 1.7 to about pH 8.4. The slurry was stirred at room temperature overnight and then dried in an oven in the presence of air at 120 ℃. The dried solid was then calcined in air at 900 ℃ for 22 hours; the resulting solid weighed 75.80 g. The catalyst was pelletized (-12 to +20 mesh, (1.68 to 0.84mm)), and 41.7g (25mL) was used in example 3.

Examples 1 to 13 and comparative examples 1 to 4

General Process for Chlorofluorination

Weigh a quantity of catalyst particles and place them in 5/8' (1.58cm) diameter Inconel^TMIn the nickel alloy reactor tube, the reaction was heated in a fluid sand bath. The reactor tube was placed under a nitrogen stream (50 cc/min; 8.3(10)^-7m³Per second) was heated from 50 ℃ to 175 ℃ over about 1 hour. Then 50 cc/min (8.3 (10))^-7m³Per second) was introduced into the reactor. After 0.5-2 hours, the nitrogen flow rate was reduced to 20 cc/min (3.3(10)^-7m³In terms of a/second),the HF flow rate was reduced to 80 cc/min (1.3(10)^-6m³Second); the flow rate was maintained for about 1 hour. The reactor temperature was then gradually increased to 400 ℃ over 3-5 hours. At the end of this period, the HF flow was stopped at 20sccm (3.3(10)^-7m³Per second) the reactor was cooled to 300 ℃ under a nitrogen flow. CFC-1213xa was fed from a pump to a vaporizer maintained at about 118 ℃. CFC-1213xa vapor with appropriate molar ratios of HF and Cl₂Packed in a 0.5 inch (1.27cm) diameter with Monel^TMSliced Monel^TMThe nickel alloy tubes were combined. Then allowing the mixture of reactants to enter a reactor; the contact time was 30 seconds unless otherwise stated. All reactions were carried out at a nominal pressure of 1 atmosphere. The results of CFC-1213xa chlorofluorination using several catalysts are shown in Table 1. Analytical data are given in units of GC area%.

Examples 14 to 17

CF₃CCl₂CClF₂By hydrodechlorination of

Using 0.5% Pd on carbon catalyst, CF₃CCl₂CClF₂The results of the hydrodechlorination are shown in Table 2. Product analytical data are given in units of GC area%. Nominal catalyst bed volume 15 mL; the contact time was 30 seconds. The catalyst was reduced in a hydrogen stream at 300 ℃ before initiating hydrodechlorination.

Examples 18 to 19

CF₃CClFCCl₂Hydrodechlorination of F

Using the 0.5% Pd on carbon catalyst, CF, used in examples 14-17₃CClFCCl₂The hydrodechlorination results for F are shown in Table 3. Product analytical data are given in units of GC area%.

Claims (7)

1. A process for the preparation of 1, 1, 1,3, 3-pentafluoropropane and 1, 1, 1, 2, 3-pentafluoropropane, which comprises:

(a) reacting hydrogen fluoride, chlorine and at least one compound of formula CX₃A halopropene of formula CCl ═ CClX, wherein each X is independently selected from F and Cl, to produce a reaction product comprising CF₃CCl₂CClF₂And CF₃CClFCCl₂F, wherein said CF₃CCl₂CClF₂And CF₃CClFCCl₂F is formed in the presence of a chlorofluorination catalyst comprisingAt least one composition selected from the group consisting of: (i) containing ZnCr₂O₄And crystalline alpha-chromium oxide; (ii) a composition comprising a zinc halide and alpha-chromium oxide; and (iii) a composition of (i) or (ii) that has been treated with a fluorinating agent;

(b) CF to be generated in (a)₃CCl₂CClF₂And CF₃CClFCCl₂F is reacted with hydrogen to form a catalyst comprising CF₃CH₂CHF₂And CF₃CHFCH₂The product of F; and

(c) recovery of CF from the product formed in (b)₃CH₂CHF₂And CF₃CHFCH₂F。

2. The process of claim 1 wherein in (a), the catalyst is selected from the group consisting of (i) catalysts comprising ZnCr₂O₄And (iii) a composition of (i) that has been treated with a fluorinating agent.

3. The process of claim 2 wherein the amount of zinc relative to the total amount of chromium and zinc in the catalyst composition is from about 1 atomic% to about 25 atomic%.

4. The process of claim 2, wherein the catalyst is selected from the group consisting of (i) catalysts comprising ZnCr₂O₄And crystalline alpha-chromium oxide, in which ZnCr is present₂O₄Comprises from about 10 atomic% to about 67 atomic% of the chromium in the composition and at least about 70 atomic% of the zinc in the composition, and wherein at least about 90 atomic% of the chromium present in the composition as chromium oxide is as ZnCr₂O₄Or crystalline alpha-chromium oxide; and (iii) the composition of (i) which has been treated with a fluorinating agent.

5. The process of claim 1, wherein in (a), the catalyst is selected from the group consisting of (ii) a composition comprising a zinc halide and alpha-chromium oxide, and (iii) a composition of (ii) that has been treated with a fluorinating agent.

6. The process of claim 5 wherein the amount of zinc relative to the total amount of chromium and zinc in the catalyst composition is from about 0.1 atomic% to about 25 atomic%.

7. The process of claim 5, wherein the catalyst is selected from the group consisting of (ii) a composition in which a zinc halide is supported on a support comprising alpha-chromium oxide, and (iii) a composition of (ii) that has been treated with a fluorinating agent; and wherein the amount of zinc relative to the total amount of chromium and zinc in the catalyst composition is from about 2 atomic% to about 10 atomic%.