Patent ID: 6326452
Filing Date: 2001-12-04
Classification: C08G

Abstract:
A process for the preparation of polyorganosiloxanes by hydrolysis of organohalosilanes of formula (I) R.sub.a R.sup.1.sub.b SiX.sub.c, wherein,R, R.sup.1 are identical or different radicals and represent hydrogen or linear or branched C.sub.1 -C.sub.6 alkyls, C.sub.6 -C.sub.12 aryls, alkylarlyls or aralkyls,X represents a halogen,and a+b+c=4 and 0<c<4; said process comprising:at least three successive hydrolysis steps (1), (2), (3), where the reaction medium isable to exert an increasing hydrolyzing force on the organohalosilanes (I), and,optionally, at least one coalescence step (4),wherein step (1) is a hydrolysis under pressure in the presence of an aqueous solution S.sub.1 which is saturated with hydrogen halide at the pressure and temperature of the reaction medium,and, in the hydrolysis step (3), water free of or almost free of dissolved solutes and/or one or several hydrogen halide aqueous solution(s) is introduced as the water source.