Preparation of hydrogenmethylpolysiloxanes with trimethylsilyl end groups, by hydrolyzing a mixture of chloromethylsilanes, separation of volatile hydrogenmethylsiloxanes then equilibration to form polymers

摘要

Method for preparing hydrogenmethylpolysiloxanes (I) having trimethylsilyl end groups. Method for preparing hydrogenmethylpolysiloxanes (I) having trimethylsilyl end groups comprises: (1) treating methyldichlorosilane (II) and trimethylchlorosilane (III), in presence of a water-insoluble organic solvent of density below 0.9 kh/l, with at most 0.5 mole water per mole hydrolyzable chlorine to form a partial hydrolyzate (X) and hydrogen chloride; (2) treating (X) with water to eliminate residual Si-Cl groups, with formation of HCl; (3) separation of volatile cyclic hydrogenmethylsiloxanes (Ia) formed; and (4) (partial) equilibration of (Ia) to sparingly volatile, essentially linear (I).