Patent GB-623227-A (GB)
Title: Improvements in or relating to the production of 3, 3, 3-trifluoro-1, 1, 2-trichloropropene-1
IPC: C07C17/20
Filed: 1947-02-17
Abstract: A pentavalent antimony fluoro-chloride catalyst is obtained by reacting antimony pentachloride with anhydrous hydrogen fluoride (suitably 1 mole. of antimony pentachloride to 5 moles. of hydrogen fluoride) at elevated temperature and pressure, and is used as a catalyst in the production of 3,3,3-trifluoro-1,1,2-trichloropropene-1 by reacting hexachloropropene and anhydrous hydrogen fluoride (see Group IV (b)). In an example the catalyst is prepared by passing cooled anhydrous hydrogen fluoride into antimony pentachloride contained in an autoclave and then heating to 150 DEG  C. while maintaining the pressure at 250 pounds per square inch.  Specification 576,190, [Group IV], is referred to.ALSO:3,3,3 -Trifluoro - 1,1,2 - trichloropropene - 1 is produced by heating in a closed vessel hexachloropropene with anhydrous hydrogen fluoride in the presence of antimony pentachloride at a temperature in the range 110 DEG  to 165 DEG  C., and at elevated pressure, at least 3 moles. of hydrogen fluoride being employed for each mole. of hexachloropropene.  The reaction product may be distilled directly from the reaction vessel and hexachloropropene, antimony pentachloride and hydrogen fluoride may be recharged to the reaction vessel and the process repeated.  An alternative method of preparation comprises heating in a closed vessel hexachloropropene with a previously prepared pentavalent antimony fluorochloride catalyst, obtained by reacting antimony pentachloride with anhydrous hydrogen fluoride at elevated temperature and pressure, and an amount of hydrogen fluoride which is at least 3 moles. of hexachloropropene at a temperature of 110 DEG C. to 165 DEG  C., and at elevated pressure, distilling the crude reaction mixture directly from the reaction vessel and then repeatedly recharging hexachloropropene and hydrogen fluoride in the same molar proportions to the reaction vessel and repeating the process.  A small additional amount of antimony pentachloride is preferably added to the reaction mixture containing the previously prepared catalyst.  In examples: (1) hexachloropropene and antimony pentachloride are charged into an autoclave fitted with a water-cooled reflux condenser and above this a second cooled reflux condenser.  The autoclave is cooled to 0 DEG  C., anhydrous hydrogen fluoride charged and the autoclave heated to a maximum temperature of 147 DEG  C. while the pressure is kept at 40 atmospheres.  The autoclave is then cooled, and the product blown into a lead beaker, washed with concentrated hydrochloric acid and then with water and then dried and distilled in a column to yield trifluorotrichloropropene and difluorotetrachloropropene; (2) antimony pentachloride and hexachloropropene are charged into an antoclave equipped with a water-cooled condenser and above it a dephlegmator cooled to a lower temperature, and anhydrous hydrogen fluoride is passed in.  The autoclave is then heated until the temperature is 160 DEG  C., the pressure being kept at 200 pounds per square inch.  After cooling and releasing the pressure the reaction products are distilled directly from the autoclave, the distillate washed and finally fractionated.  The process is then repeated after recharging the autoclave containing the residual catalyst with hexachloropropene and antimony pentachloride and passing in anhydrous hydrogen fluoride; (3) an antimony fluorochloride catalyst is prepared by passing cooled p  anhydrous hydrogen fluoride into antimony pentachloride in an autoclave equipped as in (2).  The autoclave is heated to 150 DEG  C. while the pressure is maintained at 250 pounds per square inch, and after cooling hexachloropropene and some additional antimony pentachloride are charged to the autoclave and anhydrous hydrogen fluoride passed in.  The process is continued as in (2) except that the pressure is maintained at 250 pounds per square inch.  Hexachloropropene may be prepared by reacting tetrachloroethylene with chloroform in the presence of aluminium chloride to give heptachloropropane and then treating the latter with caustic soda.  Specification 576,190 is referred to.