Process for preparing mixtures of linear organopolysiloxanes

US6232423A · kind A · utility

Assignee

• Wacker Chemie AG · DE

Inventors

• Thomas Kohler · Neuenstadt am Kocher, DE
• Manfred Meisenberger · Burghausen, DE

Key dates

• Filing date: Oct 6, 1999
• Grant date: May 15, 2001
• Expiry date: Oct 6, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G77/06
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Mixtures of linear organopolysiloxanes of the general formula 1 for EQU R.sub.3 SiO--(SiR.sub.2 O).sub.n --SiR.sub.3 (1) are produced by a process in which organochlorosilanes of the general formula 2 EQU R.sub.4-y SiCl.sub.y (2) where PA0 R is identical or different and is a hydrogen atom or an unsubstituted or substituted hydrocarbon radical having from 1 to 18 carbon atoms, PA0 Y is 1 or 2, and PA0 n is 0 or an integer from 1 to 50, are reacted continuously in a closed circulation system with water which may, if desired, have been acidified with hydrochloric acid, where the HCl concentration in the hydrochloric acid discharged is less than 25% by weight. Low molecular weight oligomer mixtures substantially free of both cyclic organosiloxanes and organosilicon compounds containing Si--Cl are economically produced.