Continuous process for producing polysiloxane oils

Abstract

Abstract A continuous process for producing linear diorganopolysiloxanes of a viscosity of from 3 to 50,000 centipoise comprising continuously passing into a first column a feed mixture comprised of cyclic siloxanes, disiloxanes, silanol-stopped linear diorganopolysiloxanes of low molecular weight and triorgansiloxy end-stopped linear diorganopolysiloxanes of low molecular weight continuously transferring into said first column acid activated hydroaluminum silicate and diatomaceous earth, maintaining said first column at a temperature in the range of 150* to 250* C, continuously removing water from said first column, continuously removing a polysiloxane fluid mixture from said first column and passing it to a second column which is packed with an acid activated hydroaluminum silicate, which second column is maintained at a temperature of 150* to 170* C and continuously transferring from the said second column the desired polysiloxane product mixed with low boilers, which low boilers can then be continuously separated from the desired polysiloxanes in a distillation column. The acid activated aluminum silicate is preferably activated with either sulfuric acid or hydrochloric acid and preferably has an acid equivalent of generally 5 to 35 milligrams of KOH per gram and more preferably 15 to 25 milligrams of KOH per gram of hydroaluminum silicate.

Inventors

• 👤 G Siciliano
• 👤 N Holdstock

Bibliographic Details