Patent GB-706703-A (GB)
Title: Improvements in or relating to organosilicon compositions
IPC: C07F7/18
Filed: 1951-02-14
Abstract: A liquid organopolysiloxane is made by hydrolysing and condensing either (1) at least one silane of the formula <FORM:0706703/IV (a)/1> where X is selected from chlorine, bromine, fluorine and halophenoxy radicals, m is an integer from 1 to 5, Y is a hydrolysable radical and n is 1 or 2, or (2) a mixture of 1 mol. of the above silane and 1 to 49 mols. of a silane of formula R2-Si-Y2, where R is a monovalent radical selected from methyl and phenyl radicals, the phenyl radicals not exceeding the number of methyl radicals.  The resulting liquid polymers may be mixed in amount of at least 0.1 per cent. by weight with liquid organo-polysiloxanes of the formula R(2a+2)-SiaO(a-1) where each R is an alkyl, cycloalkyl, aryl, alkaryl or aralkyl radical, a major proportion of the radicals being either methyl or methyl and phenyl radicals and the latter, if present, comprising at least 10 per cent. of the R radicals, and a is at least 2.  The liquid polymers may be stabilized with the metal chelates as disclosed in Specification 630,319, and may be mixed with 1 to 100 per cent. of solid lubricant materials, e.g. molybdenum disulphide, silver sulphate, tungsten sulphide and boron nitride, and with fillers, e.g. colloidal silica, talc, titania, mica powder, zinc oxide and graphite.  Examples disclose the preparation of bis(p-bromophenyl)-, bis(p-chlorophenyl)-, bis(p-fluorophenyl)-, bis(p-chlorophenoxyphenyl)-, bis(p-bromo-phenoxyphenyl)-and bis(p-fluorophenoxyphenyl)-disiloxanes and corresponding polysiloxanes tetramethyl.  The liquids, pastes or greases may be used as lubricants, and the liquids may be used as power transmission media in hydraulic machines.  Specification 544,143 also is referred to.ALSO:A liquid organopolysiloxane is made by hydrolyzing and condensing either (1) at least one silane of the formula <FORM:0706703/IV (b)/1> where X is selected from chlorine, bromine, fluorine and halophenoxy radicals, m is an integer from 1 to 5.  Y is a hydrolyzable radical and N is 1 or 2, or (2) a mixture of 1 mol of the above silane and 1 to 49 mols of a silane of the formula R2-Si-Y2, where R is selected from methyl and phenyl radicals, the phenyl radicals not exceeding the number of methyl radicals. Examples disclose the preparation of bis (p-bromophenyl)-, bis (p-chlorophenyl)-, bis- (p-fluorophenyl)- and the corresponding bis (halo-phenoxyphenyl)-tetramethyldisoloxanes.  The above silane (1) may be made by reacting magnesium in ether with a polysubstituted benzene compound, wherein one of the substituents will react with magnesium to form a Grignard reagent the other substituent(s) on the benzene ring being selected from chlorine, bromine, fluorine and halophenoxy radicals, and admixing one mol of the Grignard reagent thus formed with at least 1 mol of a methyl silane having not more than 2 methyl radicals, the remaining radicals being hydrolyzable. Alternatively, the polysubstituted benzene compound may be added slowly to the magnesium in ether, with subsquent refluxing of the mixture and separation of the required silane.  Polysubstituted benzenes specified are o-, m- and pdibromo-, trichlorobromo-, difluoroiodo-, 1-chloro-2-fluoro-4-bromo-, 4-bromo- (p-chlorophenoxy)-, tetrabromo-iodo- and pentachlorobenzenes. Examples disclose the preparation of p-bromo-, p-chloro- and p-fluorophenyldimethylchloro-and ethoxy silanes, the corresponding methyldichloro- and diethoxy silanes, and p-chlorophenoxyphenyldimethylchlorosilane.ALSO:A lubricating composition comprises a polysiloxane made by hydrolyzing and condensing at least one silane of the formula <FORM:0706703/III/1> where X is selected from chlorine, bromine, fluorine and halophenoxy radicals, m is from 1 to 5, Y is a hydrolyzable radical and n is 1 or 2, with or without a silane of the formula R2SiY2, where R is selected from methyl and phenyl radicals (see Group IV (a)).  The liquid polymers may be mixed in amount of at least 0.1 per cent. by weight with liquid polysiloxanes of the formula R (2a+2) Sia O(a-1) where each R is an alkyl, cycloalkyl, aryl, alkaryl or aralkyl radical and a is at least 2, or they may be stabilised with the metal chelates as disclosed in Specification 630,319, (Group IV (a)). Solid lubricant materials, e.g. molybdenum disulphide, silver sulphate, tungsten sulphide, and boron nitride may be added in amounts of 1 to 100 per cent. of the liquid polymers, and fillers, e.g. colloidal silica, talc, titania, mica powder, zinc oxide and graphite may also be added.