Patented June 26, 195i 2558,703 UNITED STATES PATENT OFFICE

PREPARATION OFPROPENE TRIFLUOROTRICHLORO Carl I. Gochenour, Niagara Falls, N. Y., assignor to Hooker Electrochemical Company, Niagara Falls, N. Y., a corporation of New York No Drawing. Application January 6, 1948, Serial No. 818 5 Claims. (CI. 260-653) 2 pene are unsatisfactory; when more than six The present invention relates to a method for moles of to one mole of hexa the fluorination of hexachloropropene, and is chloropropene are employed, yields of trifluoro more particularly concerned with the fluorination trichloropropene are decreased by the entrain of hexachloropropene to produce high yields of ment of product in the escaping excess HF. Also, ... trifluorotrichloropropene, and especially 1,1,1-tri the use of more than 6 moles is economically fluoro-2,3,3-trichloro-2,3- impractical. (CF3-CCECC) 3. The presence of pentavalent antimony It has been proposed to fluorinate hexachloro halide in catalytic amounts, from about 0.2 to 2.0 propene with antimony (III) fluoride and a cata 10 per cent by weight of the hexachloropropene be lyst, and this method of fluorination, although ing preferred. Representative catalysts are anti operative, is too expensive for economic .com mony (V), chloride, antimony (V) bromide, anti mercialization. It has also been proposed previ mony (V) fluoride, and antimony (V) chlorofluo-. ously to fluorinate hexachloropropene by heating rides. The antimony (V) chloride or chloroflu it together with a and an alumi 5 orides are preferred. Less than about 0.2 per num halide to accomplish exchange of the flu cent of catalyst is usually not as satisfactory for orine atom or atoms in the fluoromethane and practical yields; more than about 2.0 per cent atoms other than in the hexa does not appreciably increase the yield. chloropropene. This process is more fully dis 4. A reaction temperature between room tem closed in United States Patent 2,404,706, issued 20 perature, e. g., 20-30 degrees centigrade, and July 23, 1946. The halogen-interchange reaction about 100 degrees centigrade; 40-90 degrees cen between a fluoromethane and trihalomethyl tigrade being preferred. Yields of desired prod ethylenic compounds, however, has obvious dis uct appear to decrease with higher temperatures advantages, namely, the necessity of employing when operating at atmospheric pressure, due to an aluminum halide, and that the process de 25 increased volatility and entrainment of product mands two separate steps, i. e., the production of in the escaping HF. the fluoromethane, and reaction of the trihalo 5. The introduction of the substantially anhy methylethylenic compound therewith. It has drous hydrogen fluoride into a mixture of catalyst heretofore been considered that an allyl halide, and hexachloropropene. The hydrogen fluoride such as hexachloropropene, cannot be fluorinated 30 may be introduced batchwise when the reaction with hydrogen fluoride because the first step of is conducted under superatmospheric pressure; Such a reaction is addition to the double bond or or portionwise or continuously when conducted because HF is an active ally polymerization cata at atmospheric pressure, preferably the latter, lyst. Thus, methallyl chloride and hydrogen into the mixture until the required amount has been introduced. fluoride react to form the chlorofluoride 35 6. Agitation of the reaction mixture is required for highest yields. The agitation resulting from (Organic Reactions, New York, John Wiley and introduction of the hydrogen fluoride may be Sons, Inc., 1944, volume II, page 52). sufficient, but additional agitation is preferred. However, in direct contrast to the published 40 7. The pressure preferably should not exceed findings of prior investigators, I have found that autogenous, e. g., the of reactants hydrogen fluoride and hexachloropropene may be and reaction products under the conditions emi reacted, under certain conditions, to produce ex ployed or slightly above. This pressure is at ceedingly high yields, up to 77 per cent, of tri tained in a closed autoclave. Pressures lower than autogenous may be utilized, but pressures fluorotrichloropropene, without addition to the 45 below atmospheric are not generally satisfactory. double bond. Excessively high pressures over and above the The conditions, which I have found necessary autogenous pressures attainable, appear to reduce for the fluorination reaction are as follows: the yield of desired product, possibly by causing 1. The use of substantially anhydrous hydrogen hydrogen fluoride addition to the double bond of fluoride. 50 2. A reactant ratio of at least three moles of the product. hydrogen fluoride for each mole of hexachloro 8. The reactor for the process may be one of . propene. When less than three moles of hydro several types. A rocking autoclave constructed gen fluoride per mole of hexachloropropene are of steel or iron is satisfactory. Alternatively, a employed, COnversions to trifluorotrichloropro 55 reactor of Suitable material, e.g., nickel, iron, or 2,558,708 3 4. copper, equipped with a or Dry-Ice cooled rate of 2.25 parts per hour for a period of 8.75 reflux condenser, a scrubber for neutralizing hours, the temperature of the reaction being evolved , and a discharge line may be em- maintained at about 40 degrees centigrade dur ployed. The type of apparatus is not to be ing the course of the reaction. Fractional distill construed as limiting the invention. . . 5 lation of the dry crude product gave a 56.6 per 9. The reaction product may be separated ac cent yield of trifluorotrichloropropene. cording to conventional procedure for the treat ment of halogen-containing reaction products, Example y e.g., by cooling, Washing with water, neutraliz Example I was repeated except that 30.5 parts ing with dilute base, drying, and fractionally dis- 10 of hydrogen fluoride was introduced at the rate tilling to isolate the desired 1,1,1-trifluoro-2,3,3- of 1.97 parts per-hour for a period of fifteen and trichloro-2,3-propene. One-half hours. Fractional distillation resulted This invention will be further understood from in a 65 per cent yield of trifluorotrichloropro a consideration of the following illustrative ex pene, amples, in which the quantities are stated in 5 Eacample VI parts by weight and the yields are given in per Ten thousand parts of hexachloropropene and cent of theory, based on the hexachloropropene 30 parts of pentavalent antimony halide catalyst charged. (SbFs) were charged into an apparatus similar Eacample I to that used in Example I, except that the re Seventy-eight and one-fourth parts of hexa 20 actor was constructed of iron and was not nickel chloropropene and 0.7825 part of antimony pen lined. Three thousand six hundred parts of an tachloride were charged into a nickel-lined re hydrous hydrogen fluoride was introduced into actor which was provided with hydrogen fluoride the agitated charge over a period of four hours inlet, agitator, water-cooled reflux condenser, at the rate of 900 parts per hour, and the reac scrubber for neutralizing evolved acids, and a 25 tion temperature was increased to 90 degrees discharge line. Twenty-two and nine-tenths centigrade during the reaction. The crude prod parts of substantially anhydrous hydrogen fluo uct was treated as in Example I and on frac ride was introduced into the agitated reactor at tional distillation yielded 132 parts of trifluoro the rate of 1.9 parts per hour over a period of trichloropropene boiling between 86.9 and 89.9 twelve hours. The temperature of the reaction degrees centigrade. mixture was increased gradually from about The results and differences in reaction condi twenty-three degrees centigrade at the begin tions of the foregoing examples can be more ning pf the reaction to about forty-seven degrees readily observed from the following table: centigrade at the end of the twelve-hour period. 35 After introduction of the hydrogen fluoride was Moles HF Temper- o complete, the reaction products were cooled, Ex- Per Cent, Reaction. Yield, washed with water, neutralized with a dilute afie Catalyst P:gle age, "FG" cFéi, aqueous Solution of sodium , Separated, Hours Per cent dried with soda, ash, and fractionally distilled. I------i.0% SbCls--- 3.65 23-47 2 76.6 40 II----- 0.5% SbCls---- 4.57 23-45 2.5 64, 6 The forty-eight parts of trifluorotrichloropro III---- 1.0% ShCls.--- 3.0 23-47 0.5 71.4 pene, boiling between 86.5 and 89.7 degrees cen IV---- 0.5% SbCis-- 3.48 40 8.75 56.6 tigrade, having a specific gravity of 1.6095 at V----- 1.0% SbCls--- 4.84 23-47 5.5 65.0 25/4 and no of 14100 was separated, a 76.6 VI.-- 0.3%, SbFs---- 4.5 90 4.0 1.65 per cent yield. - 45 The product of Example VI included difluoro Eacample II tetrachloropropane in a yield of 67.5%. The low Seventy-one parts of hexachloropropene and yield of trifluorotrichloropropene in Example VI 0.355 part of antimony pentachloride were is attributable to the short reaction period, the charged into an apparatus similar to that used in Small proportion of catalyst and the higher tem Example I. Twenty-six parts of anhydrous hy 50 perature. drogen fluoride was introduced into the agitated Various modifications may be made in the reactor at the rate of about 1.93 parts per hour present invention without departing from the over a period of 13.5 hours. The temperature Spirit or Scope thereof and it is to be understood Of the reaction mixture was maintained from that I limit myself only as defined in the ap about 23 degrees centigrade to about 45 degrees 5 5 pended claims. centigrade during the course of the reaction. After claim: introduction of the hydrogen fluoride was com 1. A process for the production of 1,1,1-tri plete, the reaction products were cooled, washed, fluoro-2,3,3-trichloro-2,3-propene which com neutralized, separated, and dried as in Example prises progressively adding anhydrous hydrogen I. Fractional distillation of the product sepa 60 fluoride to a mixture of hexachloropropene con rated 36.8 parts of trifluorotrichloropropene boil taining suspended therein an amount of penta ing between 87 degrees and 89 degrees centigrade, Valent antimony halide within the range of ap a 64.6 per cent yield. - proximately 0.2 to approximately 2.0 percent by Eacample III Weight of the hexachloropropene, progressively increasing the temperature of the mixture during Example I was repeated except that 19.5 parts the addition of the hydrogen fluoride to a maxi Of hydrogen fluoride Was introduced at the rate mum within the range of approximately 40 de of 1.85 parts per hour for a period of 10.5 hours. grees centigrade to approximately 90 degrees Upon fractional distillation of the dry crude centigrade, stopping the addition of the hydrogen product, a 71.4 per cent yield of trifluorotrichloro 70 fluoride when an amount within the range of propene was obtained. approximately three to approximately six molec Eacample IV ular proportions of hydrogen fluoride (HF) have been added for each molecular proportion of Example II was repeated except that 19.75 hexachloropropene, maintaining the temperature parts of hydrogen fluoride was introduced at the 75 after the addition of the hydrogen fluoride be

2,558,708 5 tween approximately 40 and approximately 90 that at least 50 per cent of the hexachloropro degrees centigrade for a sufficient period to Con pene is converted to 1,1,1-trifluoro-2,3,3-tri vert at least 50 percent of the hexachloropro chloro-2,3-propene, and subsequently separating pene to 1,1,1-trifluoro-2,3,3-trichloro-2,3-pro the 1,1,1-trifluoro - 2,3,3-trichloro-2,3-propene pene, and subsequently recovering the 1,1,1-tri from the reaction product. fluoro-2,3,3-trichloro-2,3-propene from the reac 4. A process as defined in claim 3 in which the tion product. heating is conducted at a temperature between 2. A process for the production of 1,1,1-tri approximately 40 and approximately 90 degrees fluoro-2,3,3-trichloro-2,3-propene which comprises centigrade and the reaction mixture is agitated progressively introducing approximately 26 parts O continuously during the heating period. by weight of anhydrous hydrogen fluoride into an 5. A process as defined in claim 3 in which the agitated mixture of approximately 71 parts by pentavalent antimony halide is antimony penta weight of hexachloropropene and approximately chloride. 0.355 part by weight of antimony pentachloride, CAR. I. GOCHENOUR. maintaining the temperature of the reaction mix 5 ture within the range of approximately 23 to REFERENCES CITED approximately 45 degrees centigrade for such The following references are of record in the period that at least 50 percent of the hexachloro file of this patent: propene is converted to 1,1,1-trifluoro-2,3,3-tri chloro-2,3-propene, and subsequently recovering 20 UNITED STATES PATENTS the ,1,1-trifluoro-2,3-trichloro-2,3-propene from Number Name Date the reaction product. 2,005,713 Holt et al. ------June 18, 1935 3. A process for the production of 1,1,1-tri 2,230,925 Benning ------Feb. 4, 1941 fluoro-2,3,3-trichloro-2,3-propene from hexa 2,404,706 Harmon ------July 23, 1946 chloropropene, which comprises heating hexa 25 FOREIGN PATENTS chloropropene with between approximately 3 and approximately 6 moles of substantially anhy Number Country Date drous hydrogen fluoride per mole of hexachloro 576,190 Great Britain ------Mar. 22, 1946 propene in the presence of between approximately OTHER REFERENCES 0.2 and approximately 2.0 per cent by weight of 30 a pentavalent antimony halide, based on the Henne et al., Jour. Am. Chem. Soc., vol. 65, Weight of the hexachloropropene, at a tempera 271-2 (1943). ture between approximately 20 and approxi Henne et al., Jour. Am. Chem. Soc., vol. 63, mately 100 degrees centigrade, for such period 348-9 (1941).