GB627136A - Improved manufacture of organo-siloxane polymers - Google Patents

Abstract

A mixture of approximately one molecular proportion of an ester of orthosilicic acid and four molecular proportions of a hydrolysable triorgano-silane is hydrolysed to give an organo-siloxane polymer having less than 41 carbon atoms and of the general formula: <FORM:0627136/IV (a)/1> where R, R1 and R11 are hydrocarbon radicals and n is a whole number. An acid or alkaline catalyst may be used. The products are liquid or solid and are soluble in organic solvents such as hydrocarbons, chlorinated hydrocarbons, aromatic solvents; the liquid may be used as hydraulic fluids or heat transfer media. In examples: (1) ethyl orthosilicate and trimethyl ethoxysilane were hydrolysed and distilled to give liquid [(CH3)3SiO]4Si-as well as (CH3)6Si2O-, and a residue in which n of the above formula was greater than 1; (2) dimethylphenyl ethoxysilane and tetraethyl orthosilicate, and (3) ethyl dimethyl chlorosilane and tetraethyl orthosilicate, were hydrolysed and distilled to give corresponding polymers.ALSO:A mixture of approximately one molecular proportion of an ester of orthosilicic acid and four molecular proportions of a hydrolyzable triorgano-silane is hydrolysed to give an organo-siloxane polymer having less than 41 carbon atoms and of the general formula <FORM:0627136/IV (b)/1> where R, R1 and R11 are hydrocarbon radicals and n is a whole number. An acid or alkaline catalyst may be used. In examples: (1) ethyl orthosilicate and trimethyl ethoxysilane were hydrolysed and distilled to give liquid [(CH3)3SiO]4Sias well as (CH3)6Si2O-, and a residue in which n of the above formula was greater than 1; (2) dimethylphenyl ethoxysilane and tetraethyl orthosilicate, and (3) ethyl dimethyl chlorosilane and tetraethyl orthosilicate, were hydrolysed and distilled to give corresponding polymers.