Abstract: For the continuous hydrolysis of organochlorosilane, a reaction system comprising at least three stages of hydrolysis is used. Each stage includes a reactor and a phase separator wherein hydrolysis is effected to form a hydrolysis mixture which is separated into a hydrolyzate and a hydrogen chloride-containing aqueous medium. The separated aqueous medium is circulated to the reactor. The hydrolyzate is conveyed to the reactor of the subsequent stage. The organochlorosilane is fed into the first stage reactor, the aqueous medium containing an amount of water corresponding to the consumption in one stage is fed into one stage reactor from the subsequent stage, and an amount of water corresponding to the consumption in the overall reaction system is fed in the last stage. Then the entire amount of hydrogen chloride generated in multiple stages of hydrolysis is recovered as anhydrous hydrogen chloride from the first stage.

Abstract: Proposal is given of a method for the preparation of an organopolysiloxane highly freed from any trace amount of the residue of sulfuric acid or fuming sulfuric acid by the siloxane rearrangement reaction of organosiloxane oligomers into equilibirium by using the acid catalyst. The inventive method comprises subjecting the reaction mixture, after completion of the reaction but before the conventional step of washing with a large volume of water to remove the acid residue, to a hydrolysis reaction of the acid residue bonded to the organopolysiloxane molecules with admixture of a limited amount of water and separating the mixture into aqueous and organopolysiloxane phases to discard the acid-containing aqueous phase.