Wacker-chemie Gmbh

Wolfgang Jacques

Bernd Pachaly

Rudolf Strasser

Rudolf Riedle

Helmut Spork

Gerhard Nagy

Johann Waas

Robert Christa

The present invention describes a process wherein dimethyldichlorosilane is reacted, in a first step, with water present in hydrochloric acid to give a crude hydrolysate comprising cyclic and linear, chlorine-containing polydimethylsiloxanes and gaseous hydrogen chloride and, in a second step, the crude hydrolysate is treated with steam to reduce the chlorine content and form hydrochloric acid, with the hydrochloric acid formed in the second step being used in the first step.

Process for preparing polydimethylsiloxanes

An improved process for preparing organosiloxanes and alkyl halides by passing organohalosilanes and alkanols having 1 and/or 2 carbon atoms through at least one layer of packing material which is maintained at a temperature of from 60.degree. to 150.degree. C, the improvement which comprises (1) recycling from 1 to 6 liters of an aqueous phase separated from the organosiloxanes emerging from the layer or layers of packing material for each mol of organohalosilane introduced into the layer or layers of packing material and (2) reacting the organosiloxane separated from the aqueous phase with from 2 to 10 percent by weight based on the weight of the organosiloxane with the same organohalosilane which is passed through the layer or layers of packing material.

Process for preparing organosiloxanes

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Burghausen, Germany

Wolfgang Jacques