Patent GB-761053-A (GB)
Title: Improvements in manufacture of perhalocarbon oils
IPC: C07C17/20
Filed: 1953-02-24
Abstract: Perhalocarbons containing fluorine are fluorinated by treatment with chlorine trifluoride at a final temperature of at least 200 DEG  C., preferably not above 300 DEG  C.  The perhalocarbons may be obtained by polymerizing or copolymerizing perhalo-olefines such as trifluorochloro- and tetrafluoro-ethylene and perfluorobutadiene, to produce oils and greases and waxes of softening point of up to 200 DEG  C. and pyrolysing or cracking the product before or after separation into its constituents.  The cracked perhalocarbon oil is separated from lower boiling perhalocarbons and may be further fractionated before fluorination.  Perfluorochloro-olefines used for making perhalocarbons should not contain more than one atom of chlorine per atom of carbon.  When using trifluorochloroethylene polymerization may be effected in the liquid phase in the presence of chain transfer solvents and promoters at about 0-300 DEG  C. or higher temperatures in the absence of solvents and/or promoters and cracking may be effected at about 300-400 DEG  C.  The monomer, solvent and catalyst may be added continuously or intermittently to the polymerizable mix.  Specified solvents are chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroethylene, 1,2-dichloroperfluorocyclobutane and trichloroethylene. Promoters are free oxygen and organic peroxides, those specified being acetyl, mono-, di- and trichloracetyl, fluoro- and dichlorofluoro-acetyl and benzoyl and p-bromo-benzoyl peroxides. Fluorination may be effected downwardly through a column the temperature in the upper part being 80-200, preferably 100-150 DEG  C. and in the bottom part being at least 200 DEG , preferably above 250 DEG  C., or the temperature may be constant throughout the length of the column.  Preferably the cracked polymer is in contact with the fluorinating agent for less than about 2-3 hours.  An illustration is given of the use of suitable apparatus and in an example trifluorochloroethylene is treated with chloroform and benzoyl peroxide at 212 DEG  C. and 200-255 pounds per square inch gauge and the polymer product recovered and cracked at about 180-380 DEG  C. and 25 mm. to yield a perhalocarbon which is either fluorinated in stages with final temperatures of 100 DEG , 150 DEG  and 200 DEG  C. or fluorinated at a final temperature of 250 DEG  C. Specification 695,811, [Group IV (b)], is referred to.ALSO:Perhalocarbons are fluorinated by treatment with chlorine trifluoride at a final temperature of at least 200 DEG C., preferably not above 300 DEG  C.  The perhalocarbons used are compounds consisting substantially exclusively of carbon and halogens at least one of which is fluorine with any degree of saturation and containing less than 2 per cent of other elements such as hydrogen and oxygen.  Fluorination may result in addition of fluorine or the replacement of hydrogen and chlorine by fluorine the products generally boiling within the range of about 100-250 DEG  C. at 1-2 mms. Hg. pressure.  The perhalocarbons may be obtained by polymerizing or copolymerizing perhaloolefines such as trifluorochloro- and tetrafluoroethylene and perfluorobutadiene, to produce oils and greases and waxes of softening point of up to 200 DEG  C. and pyrolysing or cracking the product before or after separation into its constituents.  The cracked perhalocarbon oil is separated from lower boiling perhalocarbons and may be further fractionated before fluorination.  Perfluorochloroolefines used for making perhalocarbons should not contain more than one atom of chlorine per atom of carbon.  When using trifluorochloroethylene polymerization may be effected in the liquid phase in the presence of chain transfer solvents and promoters at about 0-300 DEG  C. or higher temperatures in the absence of solvents and/or promoters and cracking may be effected at about 300-400 DEG  C.  Specified solvents are chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroethylene, 1,2 - dichloroperfluorocyclobutane and trichloroethylene.  Promoters are free oxygen and organic peroxides, those specified being acetyl, mono-, di- and tri-chloro-, fluoro-and dichlorofluoro-acetyl and benzoyl and p-bromo-benzoyl peroxides. Fluorination may be effected downwardly through a column, the temperature in the upper part being 80-200, preferably 100-150 DEG  C. and in the bottom part being at least 200 DEG  C., preferably above 250 DEG  C. or the temperature may be constant throughout the length of the column.  Preferably the cracked polymer is in contact with the fluorinating agent for less than about 2-3 hours.  An illustration is given of the use of suitable apparatus and in an example trifluorochloroethylene is treated with chloroform and benzoyl peroxide at 212 DEG  C. and 200-255 pounds per square inch gauge and the polymer product recovered and cracked at about 180-380 DEG  C. and 25 mms. to yield a perhalocarbon which is either fluorinated in stages with final temperatures of 100 DEG , 150 DEG  and 200 DEG  C. or fluorinated at a final temperature of 250 DEG  C. Specification 695,811 is referred to.