United States Patent (19) 11) 4,438,088 Weaver 45 Mar. 20, 1984

54) PREPARATION OF ANTMONY 1,984,480 12/1934 Henne ...... 423A-66 TRFLUOROOCHLORDE AND 2,013,050 9/1935 Henne ...... 570/170 2,787,646 4/1957 Hazeldine ... 570/160 FLUORNATION OF FLUORNATABLE HYDROCARBONS AND HALOCARBONS 4,078,007 3/1978 Ferstandig. ... 570/170 THEREWITH Primary Examiner-Edward J. Meros Assistant Examiner-Robert L. Stoll 75 Inventor: John D. Weaver, Lake Jackson, Tex. Attorney, Agent, or Firm-Norman L. Sims; Douglas N. (73) Assignee: The Dow Chemical Company, DeLine Midland, Mich. 57 ABSTRACT 21 Appl. No.: 357,342 The invention disclosed herein is a method for prepar 22 Filed: Mar. 11, 1982 ing antimony trifluorodichloride whereby antimony (51) Int. Cli...... C01B 7/24 trifluoride is dispersed in a liquid organic medium to (52) U.S. C...... 423/466; 570/144; form a slurry and contacted with chlorine. The inven 570/145; 570/154; 570/160,570/170,570/175 tion further comprises a process for fluorinating a fluo 58 Field of Search ...... 570/144, 145, 154, 160, rinatable hydrocarbon or halocarbon whereby a fluori 570/170, 175; 423/466, 87; 252/441 natable hydrocarbon or halocarbon is contacted with the antimony trifluorodichloride prepared in the above 56) References Cited process, and the fluorinated product is distilled off. U.S. PATENT DOCUMENTS 1,930,129 4/1930 Midgley et al...... 570/170 16 Claims, No Drawings 4,438,088 2 natable hydrocarbon or halocarbon is contacted with PREPARATION OF ANTMONY the antimony trifluorodichloride prepared in the above TRIFLUORODICHELORIDE AND FELUORINATION process, and the fluorinated hydrocarbon or halocarbon OF FLUORNAABLE HYDROCARBONS AND product is distilled off. HALOCARBONS THEREWITH DETAILED DESCRIPTION OF THE BACKGROUND OF THE INVENTION INVENTION This invention involves a novel process of making According to the invention, antimony trifluoride in antimony trifluorodichloride and using it to fluorinate a the form of a dry, finely powdered solid, is dispersed in fluorinatable hydrocarbon or halocarbon in one reac 10 the organic liquid medium so as to create a slurry. The tion vessel. Antimony trifluorodichloride is an ex slurry is then contacted with chlorine, which is best tremely effective agent for the exchange of fluorine introduced in gaseous form. After the reaction has gone atoms for other halogen atoms on aliphatic hydrocar to completion, a liquid phase of antimony trifluorodi bons. See Henne, U.S. Pat, No. 1,978,840. chloride is formed which is insoluble in the liquid or It is already known to prepare antimony trifluorodi 15 ganic medium. This allows easy separation of antimony chloride by reacting antimony trifluoride and antimony trifluorodichloride from the liquid organic medium by pentachloride as disclosed by F. Swartz, Bull. Acad. decanting. Roy, Belg., 3 (24), p. 474 (1892), The medium in which the antimony trifluoride is Daudt et al., in U.S. Pat. No. 2,005,705, disclosed the dispersed may be any organic liquid. Preferably, the reaction of antimony pentachloride with hydrogen fluo 20 ride, and Dehnicke et al., Z. Anorg. Allgem. Chen, 323, liquid organic medium has a boiling point of above 267-74 (1963) (CA 59:12300n), taught a process of re about 50° C., more preferably above about 90° C. and acting ClF3 and antimony pentafluoride in the presence most preferably above about 150 C, The liquid organic of excess chlorine. medium is preferably a fluorinatable hydrocarbon, a It is also known to prepare antimony trifluorodichlo 25 fluorinatable halocarbon or an inert organic liquid, such ride from antimony trifluoride by contacting the solid as a perfluorocarbon. reactant with gaseous chlorine in the absence of a liquid Chlorine is added to the slurry up to an amount equi reaction medium. In this process, disclosed by A. molar to the antimony trifluoride. As more chlorine is Henne, Organic Reactions, 2, 49 (1944), solid antimony added to the antimony trifluoride, the product becomes trifluoride is charged to a high pressure steel cylinder. 30 a stronger fluorinating agent until the product is pure The cylinder is then sealed, evacuated and chlorine in antimony trifluorodichloride. Chlorine in excess of this molar ratios of 5 to 100 percent of the antimony trifluo amount will not adversely effect the reaction. ride is added. The cylinder must be heated and cooled During the chlorination of the antimony trifluoride it for the antimony trifluorodichloride, a viscous liquid, to is not necessary to heat the reaction mixture, but with flow and expose fresh surfaces of antimony trifluoride. 35 out doing so the reaction goes very slowly. The reac Occasional rolling of the cylinder helps to expose fresh tion starts faster if the temperature is raised to between surfaces of antimony trifluoride. The antimony tri about 50° C. to 150° C., preferably 70° C. to 130 C, fluorodichloride from this process is extremely viscous most preferably 70° C. to 90° C. Since the reaction is and cannot be easily poured from the reaction flask. exothermic, heating can be stopped and cooling may be Further, due to the low available surface area at which required once the reaction has started. chlorine may react with antimony trifluoride and the Pressure does not affect the reaction significantly, disparate phases of the two reactants, the reaction is thus the process may be run at any pressure including extremely slow and not all of the antimony trifluoride is atmospheric pressure. The process can be done in any consumed even in the presence of excess chlorine. dry atmosphere which does not interfere with the reac In Henne, U.S. Pat. No. 1,984,480, antimony trifluo 45 tion and is best done under an inert gas atmosphere, ride was contacted with chlorine in the presence of such as nitrogen. either liquid antimony trichloride or antimony penta One of the uses for antimony trifluorodichloride is as chloride, thereby producing a mixture of antimony a fluorinating agent. This invention includes a process trifluorodichloride and antimony pentachloride. As a for fluorinating a fluorinatable hydrocarbon or halocar fluorinating agent, the mixture thus produced is not as 50 effective as antimony trifluorodichloride alone. A diffi. bon comprising contacting chlorine with antimony tri cult to perform distillation of the binary mixture is fluoride dispersed in a liquid organic medium to prepare therefore required in order to provide a suitably pure antimony trifluorodichloride and thereafter contacting form of antimony trifluorodichloride. the antimony trifluorodichloride with a fluorinatable it would be desirable to provide a method whereby 55 hydrocarbon or halocarbon. antimony trifluorodichloride is prepared expeditiously, The fluorinatable hydrocarbon or halocarbon can be in high purity free of additional halogenated antimony contacted with the antimony trifluorodichloride in sev compounds and in a manner easily adapted to further eral ways. The antimony trifluorodichloride may be employ the antimony trifluorodichloride as a fluorinat decanted from the liquid organic medium and then ing agent. contacted with the fluorinatable hydrocarbon or halo carbon. Alternatively, the fluorinatable hydrocarbon or SUMMARY OF THE INVENTION halocarbon can be added to the reaction vessel in which The invention disclosed herein is a method for pre the antimony trifluorodichloride is made. The latter is paring antimony trifluorodichloride whereby antimony the preferred method of contacting. If the fluorinatable trifluoride is dispersed in a liquid organic medium to 65 hydrocarbon or halocarbon is a liquid it may be added form a slurry and contacted with chlorine. The inven to the reaction vessel at any point in the process for tion further comprises a process for fluorinating a fluo making the antimony trifluorodichloride, or the fluori rinatable hydrocarbon or halocarbon whereby a fluori natable hydrocarbon or halocarbon can be the liquid 4,438,088 3 4. organic medium into which the antimony trifluoride is This process has several advantages over the prior art dispersed prior to chlorination. processes. Antimony trifluorodichloride is produced in If the fluorinatable hydrocarbon or halocarbon is a a faster and simpler manner than in the prior art meth solid, it can be added to the reaction mixture at any time ods, and is obtained in a more usable form, in that the before, during or after the preparation of the antimony compound which is being fluorinated can be in the same trifluorodichloride. reaction vessel in which the antimony trifluorodichlo Once the fluorinatable hydrocarbon or halocarbon ride is being made, or the antimony trifluorodichloride and the antimony trifluorodichloride have been con can easily be separated from the mixture for other uses tacted, the mixture is heated to the temperature at because of the formation in an insoluble phase. The which the fluorinated product distills. Preferably, the 10 antimony trifluorodichloride can be made and used for temperature at which the fluorinated product distills is less than 50 C. as the antimony trifluorodichloride fluorination in a glass or metal reaction vessel at atmo decomposes at that temperature. The fluorinated prod spheric pressure. Another advantage is the absence of uct is separated from the reaction mixture by distilling undesirable side products such as hydrogen chloride or the reaction mixture and collecting the vaporized prod 15 hydrogen fluoride. A further advantage is that the anti uct. The distillate is usually contaminated with small mony trifluorodichloride may be recovered by decant amounts of antimony salts, chlorine, hydrogen chloride ing it from the reaction vessel free from undesirable or hydrogen fluoride. The product is usually washed antimony halide contaminants. and dried and if necessary, it may be purified, for exam Trivalent and pentavalent antimony halides and mix ple, by distillation. 20 tures thereof are commonly used for fluorine replace The hydrocarbon or halocarbon which is fluorinated ment of other halogens. The particular antimony halide by this process can be any fluorinatable hydrocarbon or or mixture of antimony halides chosen for a fluorination halocarbon. These fluorinatable hydrocarbons or halo reaction depends upon the ease of replacement of the carbons can be represented by the formulas: halogens desired to be replaced. The relative fluorina R3CX, R2CX2 and RCX3 25 tion power of antimony halides is wherein: R is independently in each occurrence hydrogen, fluorine, phenyl, C1-C10 alkyl, C1-10 alkenyl or halo-substituted derivatives thereof; and 30 SbF3Cl2 should be chosen to fluorinate those fluorinat X is selected from the group consisting of bromine, able hydrocarbons or halocarbons which are defined iodine, and chlorine. above. These reactions involve the exchange of one or more The practice of the instant invention is further illus fluorine atoms with one or more of the halogen atoms trated by the following examples. These embodiments included in the group represented by X. The relative 35 and examples are not intended to limit the scope of the reactivity of the halogen is affected by the atoms at instantly claimed invention. tached to the same and adjacent carbon atoms. CX3 groups are the most reactive and -CX2- groups are EXAMPLE 1. quite reactive. CHX2 reacts more slowly with fluorine Preparation of 1,2,3-Trichloropentafluoropropane and CH2X and -CHX-groups are not affected by a 40 fluorine exchange reaction. In most instances, side reac A 1000-ml three-neck flask equipped with a mechani tions and decompositions increase as the hydrogen con cal stirrer, a gas entry tube and a dry ice condenser, was tent of the molecule increases. charged under nitrogen with 500 g (1.65 moles) of 2 Halocarbons are alkanes or alkenes saturated with fluoroheptachloropropane and 590 g (3.30 moles) of halogen atoms and are particularly fluorinatable and are 45 antimony trifluoride. The slurry was stirred vigorously preferred starting compounds; examples are per and heated as chlorine was distilled into the flask. After chloroethane and perchloropropane. These preferred about 10 minutes when an excess of unreacted chlorine fluorinatable halocarbons include alkanes or alkenes had accumulated and the temperature had reached 80 completely substituted with halogen atoms including C., the reaction started to proceed very quickly. The one or more fluorine atoms, for example, 2-fluorohepta 50 unreacted chlorine suddenly disappeared and heat was chloropropane. evolved. The heating mantle was removed and the The proportions of reactants are not critical. Where reaction rate was controlled by the rate of addition of the fluorination is done in the same reactor as the prepa chlorine, since it was consumed as fast as it was added. ration of antimony trifluorodichloride, the amount of The temperature of the slurry reached 90' C-100 C. antimony trifluoride used depends upon the equivalents 55 offluorine to be added to the fluorinatable hydrocarbon After about 1 hour, chlorine began to reflux on the or halocarbon product. At least 0.33 mole of antimony condenser. The addition was stopped and the slurry, trifluoride should be used for each equivalent of fluo now light brown in color, was allowed to cool. It was rine to be added to the fluorinatable hydrocarbon or determined that 247 g (3.48 moles) of chlorine had been halocarbon. The optimum ratio of antimony trifluoride added. The slurry was believed to contain 3.30 moles of to fluorinatable hydrocarbon or halocarbon is 0.5 mole antimony trifluorodichloride. The condenser was re of antimony trifluoride to 1.0 mole of fluorinatable hy placed with a distillation column and the product was drocarbon or halocarbon for each equivalent offluorine distilled from the reactor as it was formed while the to be added to the fluorinatable hydrocarbon or halo slurry was heated to 105 C-130°C. The reaction and carbon. This is because the last equivalent of fluorine in 65 concurrent distillation was continued until no more the antimony compound is the slowest to react. product was obtained. After it was washed, dried and This process will usually give a yield of over 80 per distilled, there was obtained 328 g (84 percent yield) of cent of the desired product. 1,2,3-trichloropentafluoropropane. . . . . 4,438,088 5 6 4. The process of claim 2 wherein the dispersion is EXAMPLE 2 initially heated to between about 70° C. and 90° C. when Preparation of 1,2,3-Trichloropentafluoropropane the chlorine is added. A 5-liter flask was equipped with an efficient mechan 5. A process for fluorinating a fluorinatable hydrocar ical stirrer, a thermometer, a gas entry tube and a distil- 5 bon or halocarbon comprising contacting chlorine with lation head connected to a dry nitrogen source. The antimony trifluoride dispersed in a liquid organic me flask was charged with 3880 g (12.8 moles) of 2 dium to prepare antimony trifluorodichloride and there fluoroheptachloropropane and 4575 g (25.6 moles) of after contacting antimony trifluorodichloride with a antimony trifluoride. fluorinatable hydrocarbon or halocarbon, and distilling The mixture was warmed to 80 C. and addition of 10 the fluorinated product from the reaction vessel, chlorine was begun. The heat of reaction caused the wherein the chlorination of the antimony trifluoride and temperature to rise to about 115 C. during the addition. the fluorination of the fluorinatable hydrocarbon or When the temperature began to drop again, chlorine halocarbon occur in the same reaction vessel; and addition was stopped. The mixture was heated to about wherein the fluorinatable hydrocarbon or halocarbon 110° C. and the fluorinated organic product was dis- 15 can be represented by the formula tilled from the reactor as it was formed. 1,2,3-Tri chloropentafluoropropane (2130 g, 70 percent yield) was collected at b.p. 70° C.-75 C. wherein R is independently in each occurrence hydrogen, EXAMPLE 3 fluorine, phenyl, C1-10 alkyl, C1-10 alkenyl or halo Preparation of 1,1,2-Trichlorotrifluoroethane from 20 substituted derivatives thereof; and Solid Hexachloroethane X is selected from the group consisting of bromine, iodine and chlorine. A 250-ml four-neck flask, equipped with a mechani 6. The process of claim 5 wherein the fluorinatable cal stirrer, a thermometer, a gas entry tube and a dry ice halocarbon is an alkane or alkene which is saturated condenser, is charged under nitrogen with 107 g (600 25 with halogen atoms. mmoles) of antimony trifluoride and 75 ml of per 7. The process of claim 6 wherein the fluorinatable fluorodecalin. The slurry is warmed to about 80 C. and halocarbon is perchloroethane and the fluorinated halo while it is stirred briskly, 42 g (600 mmoles) of chlorine carbon product is 1,1,2-trichlorotrifluoroethane. is added at such a rate that the temperature of the slurry 8. The process of claim 6 wherein the starting fluori remains below 100 C. natable halocarbon is perchloropropane and the fluori When all of the chlorine has reacted, the resulting 30 nated product is 1,2,2,3-tetrachlorotetrafluoropropane. mixture of antimony trifluorodichloride and per 9. The process of claim 6 wherein the fluorinatable fluorodecalin is cooled to room temperature and 95 g halocarbon has one or more fluorine atoms. (400 mmoles) of hexachloroethane are added. The con 10. The process of claim 9 wherein the starting fluori denser is replaced with a distillation head and the slurry natable halocarbon is 2-fluoroheptachloropropane and is heated with stirring. 1,1,2-Trichlorotrifluoroethane is 35 the fluorinated product is 1,2,3-trichloropentafluoro collected at b.p. 46 C-48 C. propane. EXAMPLE 4 11. The process of claim 10 whereby the two-phase system is heated to a distillation head temperature of Preparation of 1,2,2,3-Tetrachlorotetrafluoropropane between about 70° C. and 80' C. from Solid Perchloropropane 40 12. The process of claim 5 wherein the liquid organic A slurry of antimony trifluorodichloride (600 medium is a fluorinatable hydrocarbon or halocarbon. mmoles) in 75 ml of perfluorodecalin is prepared as 13. The process of claim 5 wherein the fluorinatable described in Example 3. To this is added perchloropro hydrocarbon or halocarbon is a solid which is added to pane (96 g, 300 mmoles) and the mixture is heated as the liquid organic medium. before. 1,2,2,3-Tetrachlorotetrafluoropropane is dis- 45 14. A process for the preparation of antimony tri tilled from the reaction at b.p. 110 C-112 C. fluorodichloride and use of antimony trifluorodichlo What is claimed is: ride to fluorinate a fluorinatable hydrocarbon or a fluo 1. A process for making antimony trifluorodichloride rinatable halocarbon wherein the process comprises, comprising dispersing antimony trifluoride in a liquid (1) dispersing antimony trifluoride in a fluorinatable organic medium and contacting the dispersed antimony 50 hydrocarbon, fluorinatable halocarbon or a liquid trifluoride with an amount of chlorine up to an amount organic reaction medium wherein a fluorinatable equimolar to the antimony trifluoride, wherein the liq hydrocarbon or fluorinatable halocarbon has been uid reaction organic medium is selected from a group dissolved in the liquid organic reaction medium, to consisting of fluorinatable hydrocarbons, fluorinatable form a slurry and contacting chlorine with the halocarbons and perfluorocarbons, under conditions dispersed antimony trifluoride under conditions such that antimony trifluorodichloride is prepared. 55 such that antimony trifluorodichloride is prepared; 2. A process for making antimony trifluorodichloride and comprising dispersing antimony trifluoride in a liquid (2) recovering the fluorinated hydrocarbon or fluori organic medium and contacting chlorine with the dis nated halocarbon product. persed antimony trifluoride at a temperature of between 15. The process of claim 14 wherein the fluorinated about 50 C. and 150 C.; wherein the amount of chlo- 60 hydrocarbon or fluorinated halocarbon is recovered by rine is up to that amount equimolar to the antimony elevating the temperature to that at which the fluori trifluorodichloride; and wherein the liquid organic re nated hydrocarbon or fluorinated halocarbon distills, action medium is a fluorinatable hydrocarbon or a fluo and by collecting and condensing the vaporous prod rinatable halocarbon, under conditions such that anti uct. mony trifluorodichloride is prepared. 65 16. The process of claim 15 wherein the antimony 3. The process of claim 2 wherein the dispersion is trifluorodichloride is dispersed in a fluorinatable hydro initially heated to between about 70° C. and 130 C. carbon or fluorinatable halocarbon. when the chlorine is added. s