Process for preparing diorganopolysiloxanes having terminal Si-bonded hydroxyl groups

Abstract

A process for preparing diorganopolysiloxanes having terminal Si-bonded hydroxyl groups which comprises reacting an organosilicon compound selected from a cyclic diorganopolysiloxane, a diorganodichlorosilane hydrolysis product and mixtures thereof with from 0.1 to 3 percent by weight of a diorganodichlorosilane, based on the weight of the organosilicon compound, i.e., the cyclic diorganopolysiloxane and/or diorganodichlorosilane hydrolysis product employed, in the presence of from 1 to 50 ppm by weight of phosphonitrile chloride, based on the total weight of the organosilicon compound and diorganodichlorosilane employed, to form diorganopolysiloxanes containing an Si-bonded chlorine atom in each of the terminal units, then treating the reaction mixture with water or an aqueous solution, separating off the aqueous phase from the diorganopolysiloxanes containing an Si-bonded hydroxyl group in each of the terminal units and thereafter removing the low boiling constituents by distillation.

Dependencies are inferred from the claim text.