Preparation of hydrocarbonoxy containing polysiloxanes

US4209454A · kind A · utility

Assignee

• Wacker Chemie AG · DE

Inventors

• Werner Graf · Chur, CH
• Volker Frey · Burghausen, DE
• Peter John · Burghausen, DE
• Norbert Zeller · Burghausen, DE

Key dates

• Filing date: Dec 28, 1978
• Grant date: Jun 24, 1980
• Expiry date: Dec 28, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08G77/50
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

This invention relates to an improved process for preparing polysiloxanes having hydrocarbon radicals bonded to silicon atoms via oxygen, by reacting a halosilane with an alcohol and water in the presence of the desired polysiloxane, the improvement which comprises continuously introducing into a reactor equipped with a column and possibly a reflux condenser and the desired polysiloxane, an alcohol, water and, if necessary, an acid catalyst which promotes the condensation of Si-bonded condensable groups, in an amount such that the reactor contains at least 5 percent by weight of alcohol and 0.001 to 5 percent by weight of catalyst, based on the weight of the alcohol, catalyst and polysiloxane present in the reactor in which the contents of the reactor are heated to the reflux temperature and the halosilane is introduced into the column at least one meter above the bottom of the column while continuously removing the polysiloxane from the reactor at the same rate as it is formed.