KR20010029521A - Vapor phase process for making 1,1,1,3,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropene - Google Patents

Abstract

Method for preparing 1,1,1,3,3-pentafluoropropane (HFC-245fa) and 1-chloro-3,3,3-trifluoropropene (HCFC-1233). 1,1,1,3,3-pentachloropropane (HCC-240fa) is fluorinated with HF in the gas phase in the presence of a gas phase catalyst. HCFC-1233 and any prepared 1,3,3,3-tetrafluoropropene (HCFC-1234) are recycled and further fluorinated by HF for a HCC-240fa conversion of at least 99%.

Description

Vapor phase preparation for 1,1,1,3,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropene {1,1,1,3,3- PENTAFLUOROPROPANE AND 1-CHLORO-3,3,3-TRIFLUOROPROPENE}

In recent years there has been widespread concern that certain chlorofluorocarbons will be harmful to the global ozone layer. As a result, there is a global effort to use halocarbons having almost no chlorine substituents. The preparation of hydrofluorocarbons, i.e. compounds containing only carbon, hydrogen and fluorine, thus makes them suitable for use as solvents, blowing agents, refrigerants, detergents, aerosol propellants, heat transfer media, dielectrics, fire extinguishing compositions and power cycle working fluids. There has been a growing interest in the fluorocarbon industry, which has focused its attention on developing environmentally desirable products. In this regard, 1,1,1,3,3-pentafluoropropane (HFC-245fa) is a hydrofluorocarbon with zero ozone depletion potential and is considered a chlorofluorocarbon substitute in many of these applications. . 1-Chloro-3,3,3-trifluoropropene (HCFC-1233) is another hydrocarbon substitute useful as an intermediate in the production of HFC-245fa and other fluorinated materials, as well as refrigerants, blowing agents.

It is known in the art to produce hydrofluorocarbons (HFCs) by reacting hydrogen fluoride with various hydrochlorocarbon compounds. These HFCs are not only considered to be much more environmentally beneficial than hydrochlorofluorocarbons (HCFCs) or chlorofluorocarbons (CFCs) because they do not deplete ozone, but are also advantageously flame retardant and nontoxic. HFC-245fa itself is well known in the art as described in US Pat. Nos. 2,942,036, Canada 684,687, EP 381 986A, JP 02,272,086 and WO 95/04022, which are incorporated herein by reference, but there is an economic method for continuous manufacturing. Doing was a problem in this field.

The present invention relates to the preparation of hydrofluorocarbons and hydrochlorofluorocarbons. More specifically, the present invention relates to 1,1,1,3,3-pentafluoropropane (HFC-245fa) and 1-chloro-3,3,3-trifluor by a gas phase production process in the presence of a gas phase catalyst. It belongs to the manufacturing method of loprofen (HCFC-1233).

Summary of the Invention

The inventors have developed an efficient and economical means for producing HFC-245fa on a commercial scale through steam reaction with hydrogen fluoride. This gas phase reaction is much less corrosive than the liquid phase reaction. In addition, any unreacted HF and the resulting by-products can be selectively removed and recycled to produce additional amounts of HFC-245fa.

The present invention

(a) a fluorination reaction is carried out by reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, whereby HCl, 1,1,1,3,3 Forming a reaction product consisting of pentafluoropropane, 1-chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene;

(b) providing a method for preparing 1,1,1,3,3-pentafluoropropane, comprising separating 1,1,1,3,3-pentafluoropropane from the reaction product.

The invention also

(a) a fluorination reaction is carried out by reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, whereby HCl, 1,1,1,3,3 Forming a reaction product consisting of pentafluoropropane, 1-chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene;

(b) providing a method for preparing 1-chloro-3,3,3-trifluoropropene, which comprises separating 1-chloro-3,3,3-trifluoropropene from the reaction product.

The present invention further

(a) 1,1-dichloro-3,3,3-trifluoropropane, 1-chloro-1,3,3,3-tetrafluoropropane or 1,1,3-trichloro-3,3- A fluorination reaction is carried out by reacting at least one component consisting of difluoropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, thereby giving HCl, 1,1,1,3,3-pentafluoropropane, 1 Forming a reaction product consisting of -chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene;

(b) providing a method for preparing 1,1,1,3,3-pentafluoropropane, comprising separating 1,1,1,3,3-pentafluoropropane from the reaction product.

The invention is even more

(a) 1,1-dichloro-3,3,3-trifluoropropane, 1-chloro-1,3,3,3-tetrafluoropropane or 1,1,3-trichloro-3,3- A fluorination reaction is carried out by reacting at least one component consisting of difluoropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, thereby giving HCl, 1,1,1,3,3-pentafluoropropane, 1 Forming a reaction product consisting of -chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene;

(b) providing a method for preparing 1-chloro-3,3,3-trifluoropropene, which comprises separating 1-chloro-3,3,3-trifluoropropene from the reaction product.

Detailed Description of the Preferred Embodiments

1,1,1,3,3-pentachloropropane (HCC-240fa) starting materials are generally not commercially available but can be prepared by any method known in the art. See, eg, B. Boutevin, et al, Monofunctional Vinyl Chloride Telomeres. I. Synthesis and Characterization of Vinyl Chloride Telomeres Standard, 18 Eur. Polym. J. 675 (1982); Chem. Abstr. 97: 182966c (1982) and Kotora, et al, Selective addition of polyhalogenated compounds catalyzed by copper complexes to chloro substituted ethene; 44 (2) React. Kinet. Catal. Lett. See 415 (1991).

Any water in HF will act with the fluorination catalyst to inactivate the catalyst. "Substantially anhydrous" therefore means that HF contains less than about 0.05 weight percent water and preferably less than about 0.02 weight percent water. However, those skilled in the art will appreciate that the presence of water in the catalyst can be compensated for by increasing the amount of catalyst used. HF suitable for use in the reaction can be purchased from AlliedSignal Inc. of Morristown, NJ.

Fluorination catalysts useful in the process of the present invention include any catalyst known in the art, including chromium, aluminum, cobalt, manganese nickel and iron oxides, hydroxides, halides, oxyhalides, inorganic salts thereof, and mixtures thereof. It also includes, but is not limited to these. Combinations of catalysts suitable for the present invention include Cr ₂ O ₃ / Al ₂ O ₃ , Cr ₂ O ₃ / AlF ₃ , Cr ₂ O ₃ / carbon, CoCl ₂ / Cr ₂ O ₃ / Al ₂ O ₃ , NiCl ₂ / Cr ₂ O ₃ / Al ₂ O ₃ , CoCl ₂ / AlF ₃ , NiCl ₂ / AlF ₃ and mixtures thereof, including but not limited to these. Chromium oxide / aluminum oxide catalysts are described in US Pat. 5,155,082. Chromium (III) oxides such as crystalline chromium oxide or amorphous chromium oxide are preferred, and amorphous chromium oxide is most preferred. Chromium oxide (Cr ₂ O ₃ ) is a commercially available material that can be purchased at various granularities. Preference is given to fluorinated catalysts having a purity of at least 98%. The fluorination catalyst is present in excess but at least in an amount sufficient to drive the reaction. The fluorination reaction is carried out in any suitable fluorination reaction vessel or reactor but it should preferably consist of a material resistant to the corrosive effects of hydrogen fluoride, such as vessels lined with Hastalloy, Inconel, Monel and fluoropolymers.

The reactor is preheated to the fluorination reaction temperature while anhydrous HF is transferred to the reactor. HCC-240fa and HF may be transferred to the reactor at any convenient temperature and pressure. In a preferred embodiment either or both of HCC-240fa and HF are pre-vaporized or preheated to a temperature of about 30 ° C. to about 300 ° C. prior to entering the reactor. In another embodiment, HCC-240fa and HF are vaporized in the reactor.

HF and HCC-240fa feedstocks are then adjusted to the desired molar ratios. The molar ratio of HF to HCC-240fa preferably ranges from about 3: 1 to about 100: 1, more preferably from about 4: 1 to about 50: 1, and most preferably from about 5: 1 to about 20: 1. to be.

The fluorination reaction is conducted at a preferred temperature in the range of about 80 ° C to about 400 ° C, more preferably about 100 ° C to about 350 ° C, and most preferably about 200 ° C to about 330 ° C. The reactor pressure is not critical and can be above atmospheric pressure, atmospheric pressure or under vacuum. The vacuum pressure may be between about 5 Torr and about 760 Torr.

During the fluorination reaction, HCC-240fa and HF are reacted with the fluorination catalyst in the gas phase. The reactant vapor is allowed to contact the fluorination catalyst for about 1 to 120 seconds or more preferably for about 1 to 20 seconds. For the purposes of the present invention, "contact time" is the time required for gaseous reactants to pass through the catalyst bed under the assumption that the catalyst bed is 100% void.

In a preferred embodiment, the process flow is downward through the bed of catalyst. Before each use, the catalyst is preferably dried, pretreated and activated. It may be advantageous to periodically regenerate the catalyst after prolonged use while in place in the reactor. Pretreatment may be done by heating the catalyst to about 250 ° C. to about 430 ° C. in a stream of nitrogen or other inert gas. The catalyst may then be activated by treating the catalyst with a stream of HF diluted with a large excess of nitrogen gas to obtain high catalytic activity. Regeneration of the catalyst is, for example, diluted with air or nitrogen over the catalyst at a temperature of from about 100 ° C. to about 400 ° C., preferably from about 200 ° C. to about 375 ° C. for about 8 hours to about 3 days, depending on the size of the reactor. It can be accomplished by any means known in the art, such as by passing through the air.

HFC-245fa is reacted by any means known in the art, such as by extraction and preferably by distillation, unreacted starting materials, HCl, HCFC-1233 and small amounts of 1,3,3,3-tetrafluoropro It can be recovered from the fluorination reaction product mixture consisting of by-products containing pen (HFC-1234). For example, distillation can be done in a standard distillation column at a pressure that is preferably less than about 300 psig, preferably less than about 150 psig, and most preferably less than 100 psig. The pressure of the distillation column essentially determines the distillation operating temperature. HCl can be recovered by operating a distillation column at about -40 ° C to about 25 ° C, preferably at about -40 ° C to about -20 ° C. HCFC-1233 and HFC-1234 may be recovered by operating a distillation column at about -10 ° C to about 60 ° C. Single or multiple distillation columns may be used. The distillate portion contains substantially all of the HCl, HCFC-1234, HCFC-1233 / HFC-245fa azeotropic mixtures produced in the reaction and the bottom portion contains the remaining HFC-245fa, HF and other impurities. In a preferred embodiment, HCl is removed from the fluorination reaction product. More preferably HCl is removed prior to recovery of HFC-245fa from the fluorination reaction mixture.

In a preferred embodiment, any HF present can also be recovered and recycled for subsequent fluorination reactions. Preferably 1-chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene are also recycled to the gas phase reactor to react with HF or otherwise in subsequent fluorination runs. They are recycled to a separate liquid phase reactor and reacted with HF. The liquid phase reaction is carried out at a preferred temperature in the range of about 25 ° C to about 200 ° C, more preferably about 50 ° C to about 150 ° C, and most preferably about 70 ° C to about 120 ° C. The liquid phase reaction pressure is preferably maintained at about 50 psig to about 300 psig, more preferably about 75 psig to about 200 psig, and most preferably about 100 psig to about 175 psig.

The liquid phase reactor contains a liquid fluorination catalyst. Such liquid fluorinated catalysts include, but are not limited to, transition metal halides, group IVb metal halides and group Vb metal halides, and mixtures thereof. These include but are not limited to SbCl ₅ , SbCl ₃ , TaCl ₅ , SnCl ₄ , NbCl ₅ , TiCl ₄ , MoCl ₅ and mixtures thereof. The reactants are allowed to contact the liquid fluorination catalyst in a batch or continuous manner. The reaction time is sufficient for the reaction to convert to HFC-245fa. Typically, the liquid phase reaction is carried out with a catalyst contact time of about 1 second to about 1 hour when conducted in a continuous manner and with a catalyst contact time of about 1 hour to 5 hours or more when conducted in a batch manner. The method described herein achieves the conversion of HCC-240 with a conversion rate of at least 99%. Liquid phase reaction conditions are well known in the art, for example, as described in US Pat. No. 5,395,987, which is incorporated herein by reference.

In another embodiment of the invention, the process comprises at least one 1,1-dichloro-3,3,3-trifluoropropane (HFC-243fa), 1-chloro-1,3 as starting material for the fluorination reaction. 1,1,1,3,3-pentachloro to 3,3-tetrafluoropropane (HFC-244fa) and 1,1,3-trichloro-3,3-difluoropropane (HFC-242fa) By substitution with propane (HCC-240fa). Each of these is fluorine of 1,1,1,3,3-pentachloropropane to 1,1,1,3,3-pentafluoropropane and 1-chloro-3,3,3-trifluoropropene It is an intermediate in anger. Therefore, instead of performing a fluorination reaction with HCC-240fa to form HFC-243fa, HFC-244fa and / or HFC-242fa as in situ intermediates, one or more HFC-243fa, HFC-244fa and / or HFC- You can also use 242fa directly. The preparation of these materials is known in the art or they may be prepared by separate fluorination of HCC-240fa. The fluorination and separation reactions of the present invention for the production of HCC-245fa and HCFC-1233 generally yield the same conditions as given above when HFC-243fa, HFC-244fa and / or HFC-242fa are used in place of HCC-240fa. Follow. Any difference can be readily determined by one skilled in the art.

The invention as suitably disclosed herein may be practiced in the absence of any components or steps not disclosed herein. The following unlimited examples are provided to illustrate the invention.

Example 1-4

About 132 g (about 1.33 g / cc volume density) of chromium (III) oxide catalyst was charged to a 1 inch diameter Monel pipe. The catalyst was dried and pretreated with HF before use.

The reactor was preheated to the reaction temperature while anhydrous HF was transferred to the reactor. Organic feed (HCC-240) was initiated when the reactor reached the desired temperature and pressure. The HF and organic feed was then adjusted to the desired rate. Effluent product flow was analyzed by using an online Perkin Elmer Model 8500 gas chromatograph with columns packed with 5% Fluoricol (GC).

Table 1 shows the reaction conditions, conversion and selectivity of the products. 1-chloro-3,3,3-trifluoropropene appears to be the dominant product, which is a precursor of 1,1,1,3,3-pentafluoropropane (HFC-245fa). 1,3,3,3-tetrafluoropropene is a degradation product of HFC-245fa. Recycling 1-chloro-3,3,3-trifluoropropene and / or 1,3,3,3-tetrafluoropropene to the reactor can make additional HFC-245fa. Alternatively, subsequent liquid phase reactors can be used to convert these fluoro-olefins to HFC-245fa in a yield of at least about 90%.

Example One 2 3 4 Pressure (atm) One One One One Temperature (℃) 300 325 350 270 Catalyst Life (hr) 6 17 24 30 HF feed rate (g / hr) 105 96 108 74 HCC-240 Feed Speed (g / hr) 39 40 47 41 Contact time (seconds) 2.5 2.7 2.2 3.6 HF / HCC-240 molar ratio 29 24 25 20 Conversion Rate (HCC-240%) 〉 99 〉 99 〉 99 〉 99 Selectivity (area%) 1,3,3,3-tetrafluoropropene-trans isomer-cis isomer 4.01.7 4.93.2 6.50.9 1.60.4 1,1,1,3,3-pentafluoropropane 2.1 2.1 1.8 1.8 1-Chloro-3,3,3-trifluoropropene-trans isomer-cis isomer 7714 7413 7613 8213 Dichlorotrifluoropropane 0 0 0 0.22 Trichlorodifluoropropane 0 0 0 0.15

Claims (10)

(a) a fluorination reaction is carried out by reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, whereby HCl, 1,1,1,3,3 Forming a reaction product consisting of pentafluoropropane, 1-chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene; (b) separating 1,1,1,3,3-pentafluoropropane from the reaction product. The process according to claim 1, further comprising the steps of recycling 1-chloro-3,3,3-trifluoropropene and / or 1,3,3,3-tetrafluoropropene and 1-chloro-3,3 And, reacting, 3-trifluoropropene and / or 1,3,3,3-tetrafluoropropene with HF. The process according to claim 1, wherein 1-chloro-3,3,3-trifluoropropene and / or 1,3,3,3-tetrafluoropropene are recycled to the liquid phase reactor for reaction with HF and thus A process for producing an additional 1,1,1,3,3-pentafluoropropane. The method according to claim 1, wherein the 1,1,1,3,3-pentachloropropane is pre-vaporized. The method of claim 1 wherein the HF is pre-vaporized. The method according to claim 1, wherein the 1,1,1,3,3-pentachloropropane and the HF are pre-vaporized. The process according to claim 1, wherein 1,1,1,3,3-pentachloropropane and HF are pre-vaporized in a reactor. (a) a fluorination reaction is carried out by reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, whereby HCl, 1,1,1,3,3 Forming a reaction product consisting of pentafluoropropane, 1-chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene; (b) a method for preparing 1-chloro-3,3,3-trifluoropropene, which comprises separating 1-chloro-3,3,3-trifluoropropene from the reaction product. (a) 1,1-dichloro-3,3,3-trifluoropropane, 1-chloro-1,3,3,3-tetrafluoropropane or 1,1,3-trichloro-3,3- A fluorination reaction is carried out by reacting at least one component consisting of difluoropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, thereby giving HCl, 1,1,1,3,3-pentafluoropropane, 1 Forming a reaction product consisting of -chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene; (b) separating 1,1,1,3,3-pentafluoropropane from the reaction product. (a) 1,1-dichloro-3,3,3-trifluoropropane, 1-chloro-1,3,3,3-tetrafluoropropane or 1,1,3-trichloro-3,3- A fluorination reaction is carried out by reacting at least one component consisting of difluoropropane with hydrogen fluoride in a reactor in the gas phase in the presence of a fluorination catalyst, thereby giving HCl, 1,1,1,3,3-pentafluoropropane, 1 Forming a reaction product consisting of -chloro-3,3,3-trifluoropropene and 1,3,3,3-tetrafluoropropene; (b) a method for preparing 1-chloro-3,3,3-trifluoropropene, which comprises separating 1-chloro-3,3,3-trifluoropropene from the reaction product.