Patent GB-746510-A (GB)
Title: Improvements in or relating to fluorine-containing silanes and siloxanes
IPC: C07F7/08
Filed: 1953-09-29
Abstract: The invention comprises polysiloxanes having the unit formula <FORM:0746510/IV(a)/1> where R is a trifluorovinyl, tetrafluorethyl, hexafluro-butenyl, hexafluoropropyl, octafluoroethyl, chlorodifluorovinyl, chlorohexafluorocyclopentenyl, chloro-octafluorocyclohexenyl or chlorotrifluorethyl radical, R1 is a monovalent hydrocarbon radical, n is 1 or 2, z is 0, 1 or 2, and (n + z) is not greater than 3; and also copolymers of these siloxanes with each other and with other siloxanes.  The homopolymers are prepared by hydrolysing a chlorosilane of the formula RnR1z Si Cl4-(n + z) and condensing.  The examples describe the preparation of polysiloxanes having the unit formula (1) HCF2CO2 SiO1\ml5, (2) (HCF2CF2)2SiO, (3) CF3CFHCF2 SiO1\ml5, (4) (CF3CFHCF2)2SiO, (5) CF2 = CFCHFCF2SiO1\ml5, (6) ClFHCCF2SiO1\ml5, F2HC.C.ClFSiO1\ml5 and (CF2 = CF)SiO1\ml5, (7) CF3CF2CFHCF2SiO1\ml5, (8) (CF2HCF2)(C6H5)2 <FORM:0746510/IV(a)/2> (9) (FCl.C = CF)CH3SiO, (10) ClFC = CFSiO1\ml5, (11) <FORM:0746510/IV(a)/3> (12) F2C = CF)CH3SiO, (13) F2C = CFSiO1\ml5, (14) <FORM:0746510/IV(a)/4> The materials are useful as coating compositions, electrical insulation, lubricants and hydraulic fluids.ALSO:The invention comprises silanes of the formula RnR1mSiCl4-(m+n), where R is a trifluorovinyl, tetrafluoroethyl, hexafluoro-propyl, hexafluorobutenyl, octafluorobutyl, chlorodifluorovinyl, chlorohexafluorocyclopentenyl, chloro-octafluorocyclohexenyl or chlorotrifluoroethyl radical, R1 is a monovalent hydrocarbon radical, n is 1 or 2, m is 0, 1, 2 or 3, and (m+n) is not greater than 4.  The fluorine radicals, when n is 2, may be the same or different.  The compounds, when m is 0, are best prepared by heating, at temperatures of 150 DEG  to 600 DEG  C., the corresponding unsaturated fluorocarbon with di- or tri-chlorosilane. Autogenous pressure favours the production of compounds containing saturated fluorocarbon radicals, atmospheric pressure favours the production of unsaturated compounds.  The compounds containing hydrocarbon radicals may be prepared (a) by reacting the fluorocarbon silane with a Grignard reagent, or (b) by reacting the unsaturated fluorocarbon with a silane of the formula R1xHySiCl4-(x+y), where x and y each are from 1 to 3 and their sum is not greater than 4, if desired in the presence of a catalyst, e.g. boron trichloride or trifluoride.  The compounds, which are useful as coating compositions, electrical insulation, lubricants and hydraulic fluids, may be converted to siloxanes by the usual methods (see Group IV (a)).  In the examples: (1) tetrafluoroethyl trichlorosilane is prepared from trichlorosilane and tetrafluoroethylene; (2) bis-tetrafluoroethyl dichlorosilane is similarly prepared from dichlorosilane and tetrafluoroethylene; (3) hexafluoropropyl trichlorosilane is obtained from trichlorosilane and perfluoropropylene; and (4), using dichlorosilane, bis-hexafluoropropyl dichlorosilane is obtained; (5) hexafluorobutenyl-3-trichlorosilane is prepared from trichlorosilane and perfluorobutadiene; (6) trichlorosilane and chlorotrifluoroethylene yield a mixture of isomeric trifluorochloroethyl trichlorosilanes and trifluorovinyl trichlorosilane; (7) octafluorobutyl trichlorosilane is prepared from perfluorobutylene and trichlorosilane; (8) a mixture of tetrafluoroethyl phenyl dichlorosilane and tetrafluoroethyl diphenyl chlorosilane is obtained by reacting tetrafluoroethyl trichlorosilane with phenyl magnesium bromide in diethyl ether; (9) beta-chlorodifluorovinyl methyl dichlorosilane is prepared from dichlorodifluoroethylene and methyl-dichlorosilane; and (10), using trichlorosilane, beta-chlorodifluorovinyl trichlorosilane is obtained; (11) 2-chloro-3,3-4,4-5,5-hexafluorocyclopent-1-enyl methyl dichlorosilane is prepared from 1,2-dichloro-3,3-4,4-5,5-hexafluorocyclopent-1-ene and methyldichlorosilane; (12) trifluorovinyl methyl dichlorosilane is prepared from methyl-dichlorosilane and chlorotrifluoroethylene; and (13), using trichlorosilane, trifluorovinyl trichlorosilane is obtained; (14) 2-chloro-3,3-4,4-5,5-6,6-octafluorocyclohex-1-enyl phenyl dichlorosilane is prepared from phenyl-dichlorosilane and 1,2-dichloro - 3,3 - 4,4 - 5,5 - 6,6 - octafluorocyclohex-1-ene; (15) trimethyl hexafluoropropylsilane is prepared from perfluoropropylene and trimethylsilane.  The trimethylsilane is prepared by reducing trimethylchlorosilane with lithium aluminium hydride in diethyl ether.