Patent GB-638586-A (GB)
Title: Improvements in and relating to liquid polysiloxanes
IPC: C08G77/00
Filed: 1947-10-08
Abstract: A method of producing a fluid composition of linear hydrogen-substituted polysiloxanes, some or all or which correspond to the general formula <FORM:0638586/III/1> where R represents hydrogen atom and n is an integer (which may be between 1 and 500) comprises reacting in the presence of sulphuric, hydrochloric or phosphoric acid the hydrolysis products of (1) a halogenosilane of formula H2SiX2, and (2) a compound of formula R3SiX, where X in each case is bromine or chlorine and R represents a hydrogen atom, the constituents being in the ratio of at least one mol of (1) to 0.4 mol of (2).  The hydrolysis products may be prepared separately or the reaction may be carried out by hydrolysing a mixture of silanes of the formula H2SiX2 and R3SiX and reacting the products in the presence of sulphuric hydrochloric, or phosphoric acid.  The products alone, or in admixture with metallic soaps, the products of Specification 586,187, [Group IV], (e.g. cyclic compounds of formula <FORM:0638586/III/2> or of Specification 630,911, [Group IV (a)], or with a liquid mixture of substances of the formula <FORM:0638586/III/3> may be used as electrically insulating fluids, damping or hydraulic fluids, or lubricants.  In one example a mixture of H2SiCl2 and H3SiCl is hydrolysed to yield an oily compound of formula  <FORM:0638586/III/4> The Specification as open to inspection under Sect. 91 comprises also the inclusion in the mixture to be hydrolysed of dihalo-silanes substituted by at least one hydrocarbon radical to form products having both <FORM:0638586/III/5> units between the terminal silicon atoms, where R1 is hydrogen or a hydrocarbon radical and M is a hydrocarbon radical. This subject-matter does not appear in the Specification as accepted.ALSO:A method of producing a fluid composition of linear hydrogen-substituted polysiloxanes, some or all of which correspond to the general formula <FORM:0638586/IV (a)/1> where R represents hydrogen or a monovalent hydrocarbon radical and n is an integer (which may be between 1 and 500), comprises reacting in the presence of sulphuric, hydrochloric or phosphoric acid the hydrolysis products of (1) a halogenosilane of formula H2SiX2 and (2) a compound of formula R3SiX, where X in each case is bromine or chlorine and R represents hydrogen or a monovalent hydrocarbon radical, the constituents being in the ratio of at least one mol. of (1) to 0.4 mol. of (2). R may be alkyl, cycloaliphatic, aryl, alkaryl or aralkyl.  The hydrolysis products may be prepared separately or the reaction may be carried out by hydrolysing a mixture of silanes of the formula H2SiX2 and R3SiX and reacting the products in the presence of sulphuric hydrochloric, or phosphoric acid.  In another method, hexamethyldisiloxane and one or more hydrolysis products of H2SiX2 in admixture are treated with sulphuric acid by the method described in Specification 632,954, or hydrochloric or phosphoric acid may be used.  The products alone, or in admixture with metallic soaps, the products of Specification 586,187, e.g. cyclic compounds of formula <FORM:0638586/IV (a)/2> or of Specification 630,911, or with a liquid mixture of substances of the formula <FORM:0638586/IV (a)/3> may be used as electrically insulating fluids, damping or hydraulic fluids, or lubricants.  In examples: (1) a mixture of trimethyl chlorsilane and H2SiCl2 is hydrolysed by pouring into cold concentrated hydrochloric acid and the reaction mixture is poured into excess water, and the oily product extracted; (2) a mixture of H2SiCl2 and H3SiCl is hydrolysed as in (1) to yield an oily compound of formula <FORM:0638586/IV (a)/4> (3) triphenyl chlorosilane and H2SiCl2 are reacted as in (1).  The Specification as open to inspection under Sect. 91 comprises also the inclusion in the mixture to be hydrolysed of dihalo-silanes substituted by a least one hydrocarbon radical to form products having both <FORM:0638586/IV (a)/5> units between the terminal silicon atoms, where R1 is hydrogen or a hydrocarbon radical and M is a hydrocarbon radical. This subject-matter does not appear in the Specification as accepted.ALSO:A method of producing a fluid composition of linear hydrogen-substituted polysiloxanes, some or all or which corresponds to the general formula <FORM:0638586/IV (b)/1> where R represents hydrogen or a monovalent hydrocarbon radical and n is an integer (which may be between 1 and 500) comprises reacting in the presence of sulphuric, hydrochloric or phosphoric acid the hydrolysis products of (1) a halogenosilane of formula H2SiX2, and (2) a compound of formula R3SiX, where X in each case is bromine or chlorine and R represents hydrogen or a monovalent hydrocarbon radical, the constituents being in the ratio of at least one mol of (1) to 0.4 mol. of (2). R may be alkyl, cycloaliphatic, aryl, alkaryl or aralkyl.  The hydrolysis products may be prepared separately or the reaction may be carried out by hydrolysing a mixture of silanes of the formula H2SiX2 and R3SiX and reacting the products in the presence of sulphuric hydrochloric, or phosphoric acid.  In another method hexamethyl-disiloxane and one or more hydrolysis products of H2SiX2 in admixture are treated with sulphuric acid by the method described in Specification 632,954, or hydrochloric or phosphoric acid may be used.  The products alone, or in admixture with metallic soaps, the products of Specification 586,187 e.g. cyclic compounds of formula <FORM:0638586/IV (b)/2> or of Specification 630,911, [Group IV (a)], or with a liquid mixture of substances of the formula <FORM:0638586/IV (b)/3> may be used as electrically insulating fluids, damping or hydraulic fluids, or lubricants.  In examples: (1) a mixture of trimethyl chlorsilane and H2SiCl2 is hydrolysed by pouring into cold concentrated hydrochloric acid and the reaction mixture is poured into excess water, and the oily product extracted; (2) a mixture of H2SiCl2 and H3SiCl is hydrolysed as in (1) to yield an oily compound of formula <FORM:0638586/IV (b)/4> (3) triphenyl chlorosilane and H2SiCl2 are reacted as in (1).  The Specification as open to inspection under Sect. 91 comprises also the inclusion in the mixture to be hydrolysed of dihalo-silanes substituted by at least one hydrocarbon radical to form products having both units between the terminal silicon atoms, <FORM:0638586/IV (b)/5> where R1 is hydrogen or a hydrocarbon radical and M is a hydrocarbon radical. This subject-matter does not appear in the Specification as accepted.