GB710319A - Improvements in or relating to the manufacture of siloxane polymers - Google Patents

Abstract

Siloxane polymers are prepared by contacting a silane of the general formula RxSi(OR1)4-x, wherein R and R1 are alkyl radicals having less than 4 carbon atoms and x is 0 to 3 inclusive, with an anhydrous hydrogen halide at a temperature of at least 50 DEG C. and in the presence of anhydrous ferric chloride. The ether R1OR1 is eliminated. In examples: (1) Hydrogen chloride was passed through methyl triethoxy silane containing ferric chloride at 94 DEG C. After three hours at 110 DEG C. a light silicone oil containing some ethoxy groups was obtained together with diethyl-ether: (2) Similar to (1) using dimethyldiethoxy silane giving a light siloxane oil: (3) Similar to (1) using tetraethoxysilane, giving silica: (4) As in (1) but continued for eight hours, giving a semi-liquid gel: (5) Similar to (1) using triethylethoxysilane, giving hexaethyldisiloxane. Some of the products of the invention are suitable for further condensation or polymerization with or without a catalyst or by air blowing to give resins, rubbers or oils.ALSO:Siloxanes are prepared by contacting a silane of the general formula RxSi(OR1)4-x, wherein R and R1 are alkyl radicals having less than 4 carbon atoms and x is 0 to 3 inclusive, with an anhydrous hydrogen halide at a temperature of at least 50 DEG C. and in the presence of anhydrous ferric chloride. The ether R1OR1 is eliminated. In an example hexethyldisiloxane (boiling at 231 DEG C.) was prepared by passing anhydrous hydrogen chloride into 1 gram mol. of triethyltriethoxysilane containing 0.06 gram mol. of anhydrous ferric chloride, at about 100 DEG C. Diethyl-ether was obtained as by-product. Similar examples described the production of silica and siloxane polymers.ALSO:Silica is prepared by contacting a compound of the formula Si(OR1)4, where R1 is an alkyl radical having less than four carbon atoms, with an anhydrous hydrogen halide at a temperature of at least 50 DEG C. in the presence of anhydrous ferric chloride. The ether R1OR1 is eliminated. In an example hydrogen chloride was passed through a mixture of 178 grams ethyl orthosilicate and 0.45 grams anhydrous ferric chloride for twelve hours at 125-135 DEG C. Silica was precipitated and 25 grams of ethyl ether collected.