Process for preparing diorganopolysiloxanes containing triorganosiloxy terminal groups

Claim 1

A process for preparing diorganopolysiloxanes containing triorganosiloxy terminal units which comprises reacting diorganopolysiloxanes containing triorganosiloxy groups, Si-bonded hydroxyl groups or groups capable of condensing with such groups with a hexaorganodisilazane by mixing the diorganopolysiloxanes with a hexaorganodisilazane in an amount of from 0.05 to 2 percent by weight, based on the weight of the diorganopolysiloxanes employed, and thereafter adding a chlorophosphazene as a catalyst, wherein the diorganopolysiloxanes employed are obtained from the reaction of a diorganopolysiloxane selected from the group consisting of a cyclic diorganopolysiloxane of the general formula (R.sub.2 SiO).sub.m, a diorganopolysiloxane of the general formula HO(SiR.sub.2 O).sub.n H and mixtures thereof, in which R is a monovalent hydrocarbon radical or a substituted monovalent hydrocarbon radical, m is an integer having a value of at least 3 and n is an integer having a value of at least 1, with a silicon compound selected from the group consisting of a triorganosilanol of the general formula R.sub.3 SiOH, a low-molecular-weight organosiloxane of the general formula R 3 Si(OSiR 2 ) p OSiR 3 and mixtures thereof, where R is the same as above and p is 0 or an integer having a value of from 1 to 20, in the presence of a catalyst other than chlorophosphazenes.