MXPA96006750A - Process for the manufacture of 1,1,1,3,3-pentafluoroprop - Google Patents

Abstract

The present invention relates to a process for the manufacture of 1,1,1,3,3-pentafluoropropane comprising: a) reacting a compound of the formula: CFyC13-y-CH2CHFwC12-w where W = 0o1, ey = 0-3, with hydrogen fluoride in the presence of a fluorination catalyst under conditions sufficient to produce a compound of the formula CF3CH2CF

Description

"PROCESS FOR THE MANUFACTURE OF 1,1,1,3, 3-PENTAFLUOROPROPANO" BACKGROUND OF THE INVENTION This invention relates to a novel method for making 1, 1, 1, 3, 3-pentafluoropropane, CF3CH2CF2H, which is referred to in the art as HFC-245fa. Specifically, the invention relates to the fluorination with hydrogen fluoride of a compound of the formula: CFyCl3_ and CH2CHFwCl2-w where w = 0 or 1, ey = 0-3, in the presence of a fluorination catalyst to produce HFC -245fa HFC-245fa has physical properties including a boiling temperature of about 14 ° C, which make it particularly attractive as a swelling agent. (See Ger. Offen, DE 3,903,336, 1990 (EP 381,986 A)). It also has the ability to function as an aerosol impeller (US Patent Number 2,942,036 issued to Smith and oolf) in a manner similar to trichlorofluoromethane, which is referred to in the art as CFC-11, and as a heat transfer agent ( Japanese Kokai Tokyo Koho JP 02,272,086 in 114 Chemical Extracts 125031q (1991)).

Traditionally, chlorofluorocarbons (CFCs) similar to CFC-11 and dichlorofluoromethane (CFC-12) have been used as refrigerants, swelling agents and impellants. These materials, however, are believed to contribute to the depletion of stratospheric ozone. The fluorocarbon industry, therefore, has focused its attention to develop safer alternatives for these materials estratoesféricamente. The HFC-245fa is , - a candidate replacement material, since it works essentially in the same way as CFCs but is zero ozone depletion. Due to the demand for these and other low or zero ozone depletion materials that will increase dramatically in the future, commercially viable processes are needed for their preparation. Only two methods for making HFC-245fa (which are not hydrofluorination reactions) are disclosed in the art. However, these methods are not without inconveniences. Knunyants et al., Catalytic Hydrogenation 0 of Perfl uoro Ol efins, 55 Chemical Abstracts 349f (1961), discloses the reduction of 1, 1, 1, 3, 3-pentafluoropropene in HFC-245fa. Because this process includes multiple steps, it is inefficient and ineconomic. Burdon et al., Partial Fluorination of Tetrahydrofuran with Cobalt Trifl uoride, J. Chem. Soc. (C), 1739 (1969) discloses the elemental fluorination of tetrahydrofuran to produce HFC-245fa. This process suffers from the disadvantage that it produces a host of another by-product, thereby reducing the yield of the desired product. Insofar as it relates to hydrofluorination reactions, there are no those methods for the production of HFC-245fa that is disclosed in the art and less the fluoridation reactions alone using 1,1,1,3,3-pentachloroprapane ( CCI3CH2CHCI2) as the starting material to produce HFC-245fa. Even when the conversion of the -CCI3 groups into CF3 groups is well known in the art, attempts to fluorinate the -CHCI2 groups or the CHC1F groups in CHF2 groups in compounds having two or more carbon atoms ( in particular, compounds of the formula RCH 2 CHCl 2 and RCH CHFX wherein X is Cl or Br and R is an alkyl group having at least one carbon atom) have not been satisfactory. See Henne et al., Fl uoroethanes an Fl uoroethyl enes, 58 J. Am. Chem. Soc. 889 (1936). Tarrant et al., Free Radi cal Addi ti ons Involving Fl uorine Compounds IV. The Eddi ti on of Dibromodifl uoromethane to Some Fl uoroolefins, 77. Am. Chem. Soc. 2783 (1955) disclose the fluorination of compounds of the type FC2BrCH2CHFBr with hydrogen fluoride (HF) in s' and. presence of a Sb (V) salt catalyst, such as SbCl5 and TaF5. However, this method produced only a 14 percent yield of CF3CH2CHFBr at 125 ° C and only a modest improvement in performance at 5 170 ° C occurred. Even at elevated temperatures, HFC-245fa did not occur.

DESCRIPTION OF THE INVENTION. We have discovered that the drawbacks associated with the processes of the prior art for making 1, 1, 1, 3, 3-pentafluoropropane or HFC-245fa can be eliminated by the process of our invention. That is to say, we have discovered an efficient and economical means to manufacture HFC-245fa on a commercial scale, which uses readily obtainable raw materials and which produces HFC-245fa in high yield This invention relates to a process for manufacturing 1, 1, 1, 3, 3-pentafluoropropane comprising: 1) reacting a compound of the formula: CFyCl3_yCH2CHFwCl2_w where w = 0 or 1, ey = 0-3, with hydrogen fluoride in the presence of a low fluorination catalyst conditions sufficient to produce a compound of the formula CF3CH2CF2H, and 2) optionally recover a compound of the formula CF3CH2CF2H.Organic starting materials corresponding to the formula CFyCl3_ and CH2CHFwCl_w, where w = 0 ol, ey = 0-3, include CC13CH2CHC12, CF3CH2CHCl2, CFC12CH2CHC12, CF2C1CH2CHC12, CFC12CH2CHC1F, - CF C1CH2CHFC1 and CF3CH2CHFCl, The preferred starting material is CC13CH2CHC12.These materials can not be obtained commercially. However, they can be prepared by any means known in the art. See, for example, of B. Boutevin et al., Monof uncti onal Vinyl Chioride Telomers. I. Synthesis and Characterization of Vinyl Chioride Tel omer Standards, 18 Eur. Polym. J. 675 - "(1982) in 97 Chemical Abstracts 182966c (1982), and Kotora et al., Selective Addi ons of Polyhalogenated Compounds to Chloro Substi tuted Ethenes Catalyzed by a Copper Complex, 44 (2) React, Kinet, Catal. Lett., 415 (1991) .See also the method disclosed in Examples 1 and 2 which are presented below.When CCI3CH2CHCI;? is the starting material, it is preferably prepared according to the method provided in Alternatively, CCl3CH2CHCl can be prepared by reducing CCl3CH CCl3 (see Example 2) as well as by photochlorination of CC13CH2CH2C1 Any water in HF will react with and deactivate the fluorination catalyst. an essentially anhydride HF is preferred. "essentially anhydride", is meant to mean that HF contains less than about 0.05 weight percent water and preferably contains less than about 0.02 weight percent water. However, a person skilled in the art will appreciate the presence of water in the catalyst to be compensated by increasing the amount of the catalyst used. The HF suitable for use in the reaction can be purchased from AlliedSignal Inc. of Morrison, New Jersey. Based on the reaction stoichiometry, the required molar ratio of HF to the organic substances (ie, CFyCl3_yCH2FwCl2_w) is 5-y-w (or the number of chlorine atoms in the organic starting material) up to 1.0. HF is preferably used in an amount of about 1 to about 15 times the stoichiometric amount of HF with respect to the organic materials and more preferably from about 6 to about 15 times the stoichiometric amount of HF with respect to the organic materials.

Fluoridation catalysts useful in the process of the invention include: (I.) pentavalent antimony, niobium, arsenite and tantalum halides; (II.) Mixed halides of antimony, niobium, arsenic and tantalum 5 pentavalent, and (III.) Mixtures of catalysts of antimony halide, niobium, arsenic and tantalum pentavalent. Examples of catalyst of group (I.) include antimony pentachloride and antimony pentafluoride. Examples of group (II.) Catalysts include SbCl2F3 0 and SbBr2F3. Examples of the group (III.) Catalysts include a mixture of antimony pentachloride and antimony pentafluoride. The pentavalent antimony, nibium, arsenic and tantalum halides can be obtained commercially, and the mixed halides thereof are created in-situ during reaction with HF. Antimony pentachloride is '~ preferred because of its low cost and availability. The mixed halides of pentavalent antimony of the formula SbClnF5_n, wherein n is 0 to 5, are especially preferred. The fluorination catalysts used in this invention preferably have a purity of at least about 97 percent. Although the amount of the fluorination catalyst used can be varied widely, it is recommended to use from about 5 percent by 5 percent to about 50 percent, preferably, from about 10 percent to 25 percent by weight of the catalyst, relative to the substances organic It may be advantageous to periodically regenerate the catalyst due to the dissociation of the pentavalent catalyst over time. This can be achieved by means well known in the art.

The catalyst can be regenerated, for example, by adding chlorine (in an amount of about 1 to about 10 mole percent relative to the amount of the pentavelent catalyst initially present in the reactor) to the stream in combination consisting of organic substances of the formula CFyCl3_yCH2CHFwCl2-w, and the recycled stream comprising of sub-fluorinated materials and HF. Chlorine, which is continuously added to the process of this invention when operated in a continuous mode (and is added periodically when operated intermittently) oxidizes the catalyst from the trivalent state to the pentavalent state. of the art can easily determine without undue experimentation the amount of chlorine to be added in order to optimize the use of the catalyst.The temperature at which the fluorination reaction is carried out and the reaction period will depend on the starting material and the used catalyst A person skilled in the art can easily bring to the optimum the reaction conditions without undue experiments to obtain the claimed results but the temperature will generally be within the range of about 50 ° C to about 175 ° C and preferably from about 115 ° C to about 155 ° C for a period for example about 1 to about 25 hours, and preferably about 2 to about 8 hours. 0 Pressure is not critical. Convenient operating pressures will vary from about 1,500 to about 5,000 KPa and preferably from about 1,500 to about 2,500 KPa. The equipment in which the fluorination reaction 5 is carried out is preferably made of a corrosion resistant material, such as Inconel or Monel. f ~ HFC-245fa can be recovered from the mixture of unreacted starting materials, by-products and the catalyst by any means known in the art, such as distillation and extraction. as illustrated in Example 3, at the end of the heating period, i.e. the amount of time to complete the reaction in operations intermittently, the fluorination reaction product and the remaining HF can be discharged through a Valve in the head of the autoclave which in turn connects with an acid scrubber and cold traps to collect the product.

Alternatively, the unreacted HF and the organic substances can be discharged and condensed and the HF layer can be recycled to the reactor. The organic layer can then be treated, i.e., washed with an aqueous base to remove the dissolved HF and distilled. This isolation procedure is particularly useful for a continuous fluorination process. Sub-fl uid materials, such as CF3CH2CHFCI, can be recycled in subsequent periods of operation. In another embodiment, the invention relates to a process for the manufacture of 1,1,1,3,3-pentafluoropropane comprising: 1. reacting CCI4 and vinyl chloride in the presence of a telomerization catalyst under conditions sufficient to produce a compound of the formula CC13CH2CHC12. 2. reacting a compound of the formula CCI3CH2CHCI2 with hydrogen fluoride in the presence of a fluorination catalyst under conditions sufficient to produce a compound of the formula CF3CH2CF2H; and 3. optionally recovering in a compound of the formula CF3CH2CF2H.

Telomerization of vinyl chloride by reaction with carbon tetrachloride to produce CCI3CH2CHCI2 is known in the art. See, for example, of B. Boutevin and others; Monofuncti onal Vinyl Chioride 5 Tel omers. I. Synthesi s and Characteri za ti on of Vinyl Chi oride Tel omer Standards, 18 Eur. Polym. J. 675 (1982) in the Chemical Compendices of 97 Number 182966cc (1982); and Kotora et al., Selecti ve Addi tions of Polyhal ogenated '* "Compounds to Chl gold Substi tuted Ethenes Ca talyzed by a 0 Copper Complex, 44 (2) React Kinet, Lett 415 (1991). starting for the telomerization reaction, ie, carbon tetrachloride and vinyl chloride can be obtained from commercial sources.

The molar ratio of CCI4 to vinyl chloride is about 0.5: 10, preferably 1: 8 (in order to minimize the formation of higher telomeres) and most preferably, about 1: 5. The telomerization of vinyl chloride can be initiated by any commercially available catalyst known in the art as being useful for initiating and catalyzing the telomerization of carbon tetrachloride and vinyl chloride. Suitable catalysts include but are not limited to: organic peroxides, metal salts and metal carbonyls. Copper and iron salt catalysts, such as cuprous chloride (CuCl), cuprous iodide (Cul) and iron chloride (FeCl2) are preferred. The amount of catalyst used in the telomerization reaction is at least about 0.1 to 5 to about 50 millimoles, preferably about 1 to about 20 millimoles per gram of organic substances (ie, CCl 3 CH 2 CHCl 2). An amine co-catalyst, such as "" alkanol amine, alkyl amine and aromatic amine may optionally be used to allow the use of milder conditions in the telomerization process. Examples of suitable amine co-catalysts include ethanol amine, butyl amine, propyl amine, benzylamine and pyridine. 2-Propylamine is the especially preferred co-catalyst. These co-catalysts can be obtained commercially. When a co-catalyst is used, it should be used in an amount of about 1 to about 10 moles per mole of catalyst, i.e., eg, copper salt. In order to dissolve the catalyst, a solvent that is inert to the reactants and the desired product can be used in the telomerization reaction. Suitable solvents include but are not limited to commercially available acetonitrile, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, isopropanol and tertiary butanol. Acetonitrile is preferred due to ease of handling and stability. The amount of solvent used ranges from about 5 times the amount of the catalyst used on a molar basis to about 80 percent of the total volume of the total telomerization reaction mixture (ie, solvent, catalyst, co-catalyst, tetrachloride carbon, vinyl chloride) and preferably between about 10 and 50 times the amount of the catalyst 0 used on a molar basis. The temperature at which the telomerization reaction is carried out and the reaction period will depend on the selected catalyst, the presence of a co-catalyst and the solubility of the catalyst system in the solvent. A person skilled in the art can easily bring to the optimum the reaction conditions without undue experiments to obtain the claimed results for the temperature, it will generally fall within the range of about 25 ° C to about 225 ° C, preferably from about 50 ° C to about 150 ° C. The reaction period will finally vary from about 3 to about 72 hours, preferably from about 10 to about 24 hours. The pressure is not critical.

Preferably, the telomerization reaction is carried out in a conventional apparatus such as an autoclave made of corrosion resistant materials such as Teflon and glass. Preferably, the telomerization product is recovered from the by-products, the solvent, the catalyst and the co-catalyst prior to the fluorination reaction in order to essentially eliminate the production of by-products in the fluorination step. The telomerization product can be recovered by any of the means known in the art, such as distillation and extraction, Optionally, the telomerization product can further be purified by further distillation .. Due to the toxicity of vinyl chloride, 5 others can be employed. procedures for preparing CCl3CH CHCl2. See Example 2 (reduction of / ~ * CCl3CH2CCl3). Alternatively, CCl CH2CCl3 can be prepared according to the well known telomerization reaction of vinylidene chloride with 0 carbon tetrachloride.

Example 1. Preparation of CCl CH2CHCl2 from CCI4 and CH? = CHC1 A monel autocalve of 600 milliliter capacity equipped with mechanical agitator was charged with one gram of CuCl, 156.6 grams of CCI4 and 75 milliliters of acetonitrile. The contents were cooled in an ice bath and the autoclave was closed and evacuated briefly. Then 36.7 grams of vinyl chloride were added and the contents were stirred and heated at 135 ° C for 16 hours. The volatile materials were removed by atmospheric pressure distillation. The distillation at 23 millimeters of mercury gave 0 by result 90.0 grams (71 percent yield based on the added vinyl chloride) of a colorless liquid. The identity of this liquid was confirmed through proton nuclear magnetic resonance ("NMR") as being CCl3CH2CHCl (boiling temperature from 72 ° C to 74 ° C. Nuclear magnetic resonance of ^ H (CDCI3): delta 6.15 (t , 1 H), 3.7 (d, 2 H).

Example 2. Preparation of CCI3CH2CHCI2 by reducing CCl CH? CCl A monel autoclave of 600 milliliter capacity equipped with mechanical agitator was charged with 199.9 grams of CCI3CH2CCI3, 199.5 grams of isopropanol and 4 grams of Cul. The autoclave was closed and evacuated briefly. The contents were heated to a temperature of 120 ° C to 125 ° C for 16 hours. The volatile materials, including the isopropyl chloride by-product were removed by rotary evaporation leaving 200 grams of the residue. The analysis in a device Varian gas chromatography that has a packed column ("GC analysis") indicated CC13CH2CHC12 and CC13CH2CC13 in a ratio of approximately 1: 2, respectively. Distillation at 29 millimeters of mercury resulted ; '- 107.9 grams of the starting material (boiling temperature of approximately 105 ° C to 107 ° C) and 36.9 grams (46 percent yield) of CCl3CH2CHCl2 (boiling temperature of about 85 ° C to 90 ° C).

Example 3. Fluorination of CCl3CH2CHCl2 with HF / SbCl ^ A monel autoclave of 600 milliliter capacity equipped with mechanical agitator was charged with 8.7 grams of SbCl5 and cooled to -27 ° C. The autoclave was then evacuated and charged with 49.8 grams of anhydrous HF. The contents were cooled to -40 ° C and 44 grams of CCl3CH2CHCl2 were added. The reactor was then connected to a packed column / condenser assembly. The condenser was maintained at a temperature of -20 ° C. The reaction mixture was heated at 5 135 ° C through 2.25 hours and kept at that temperature for an additional 2 hours. During this heating period, the pressure in the autoclave was maintained from approximately 1965 to 2655 KPa periodically discharging the pressure (byproduct of HCl) in excess of 2.655 KPa. The discharge operation was carried out from the top of the condenser to a cold aqueous KOH scrubber that was connected to a cold trap at room temperature. -78 ° C. The reactor was then fully discharged to the cold trap. 18.5 grams of a colorless liquid were collected. The identity of this liquid was determined by GC analysis as being 84 percent of CF3CH2CHF2 (corresponding to a yield of 57 percent) and 11 percent of CF3CH2CHC1F.

Example 4. Fluorination of CF CH? CHC1? with HF / SbF The experiment described in Example 3 was repeated with the exception that CF3CH2CHCI2 was used as the starting material. To the apparatus described in Example 3 were charged 8.2 grams of SbF5, 41 grams of HF and 37 grams of CF3CH2CHC12. (CF3CH2CHC12 was obtained by photocloration at room temperature of the commercially available CF3CH2CH2C1). This mixture was heated with stirring at a temperature of about 130 ° C to 135 ° C for 4.5 hours at a maximum operating pressure of 3.450 KPa. They recovered 18.1 grams (corresponding to a yield of 57 percent) of a colorless liquid. The GC analysis identified the material as being HFC-245fa 94 percent pure. 5 Example 5. Fluorination of CF3CH2CHC1 with HF / SbCl ^ a at 150 ° C to 160 ° C and low operating pressure.

The experiment described in Example 3 was repeated with the exception that CF3CH2CHCl2 was used as the starting material. To the apparatus described in Example 3 9.5 grams of SbC15m 47.9 grams of HF and 34.6 grams of CF3CH2CHC12 were charged. This mixture was heated with stirring at a temperature of 150 ° C to 160 ° C for 3.5 hours and kept at that temperature for an additional 2 hours. The maximum operating pressure controlled by periodic discharge of the HCl by-product was 1280 KPa. GC analysis of the crude reaction product indicated that it contained 71 percent HFC-245fa. As illustrated by the examples described above, HFC-245fa is produced in high performance without the use of high temperatures or pressures and without using large amounts of costly catalysts.

Claims (10)

R E I V I N D I C A C I O N E S;

1. A process for the manufacture of 1,1,1,3,3-pentafluoropropane comprising: a) reacting a compound of the formula: CFyCl3_yCH2CHFwCl2_w where w = 0 or 1, ey = 0-3, with hydrogen fluoride • "" in the presence of a fluorination catalyst under sufficient conditions to produce a compound of the formula CF3CH2CF2H.

2. The process according to claim 1, wherein the fluorination catalyst is selected from the group consisting of pentavalent antimony halide, pentavalent niobium halide, pentavalent arsenic halide, pentavalent tantalum halide, halide blended with pentavalent antimony. , halide mixed with pentavalent niobium, halide mixed with pentavalent arsenic, halide mixed with pentavalent tantalum and mixtures thereof.

3. The process according to claim 2, wherein the fluorination catalyst has the formula SbClnF5_n, wherein n is 0 to 5.

4. The process according to claim 2, wherein the compound of the formula CFyCl3_yCH CHFwCl2_w is selected from the group consisting of CC13CH2CHC12, CF3CH2CHC12, CFC12CH2CHC12, CF2C1CH2CHC12, CFC12CH2CHC1F, CF2C1CH2CHFC1 and CF3CH2CHFC1.

5. The process according to claim 2, wherein the compound of the formula CFyCl3_yCH2CHFwCl2_w is CC13CH2CHC12.

6. The process according to claim 1, wherein the reaction is carried out at "" temperature from about 50 ° C to about 0 175 ° C.

7. The process according to claim 1, wherein the amount of HF used is from about 1 to about 15 times the stoichiometric amount of HF, with respect to the The process according to claim 7, wherein the fluorination catalyst is present in an amount of about 5 percent to 50 percent by weight relative to the amount of the compound of formula 5. the formula CFyCl3_ and CH2CHFwCl2_w present 9. A process for the manufacture of 1,1,1,3,3-pentafluoropropane comprising: a) reacting CCI4 and vinyl chloride under conditions sufficient to produce a compound of the formula CCI3CH2CHCI2; and b) reacting a compound of the formula CCI3CH2CHCI2 with hydrogen fluoride, in the presence of a fluorination catalyst to produce a compound of the formula CF3CH2CF2H. the process according to claim 1, wherein CCI3CH2CHCI2 is recovered before 0 of step b. ~