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US 7,683,198 B2Granted
Process for preparing diorganopolysiloxanes
AssigneeWacker Chemie AG
InventorsOliver Schaefer, Sandra Bachmaier
Life of this patent
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Abstract
Mono-hydroxyl-functional organopolysiloxanes are prepared with minimal byproducts and increased storage stability by reaction of cyclotrisiloxanes with sil(ox)anols containing less than 1 weight percent water in the presence of heterogenous alkali metal or alkaline earth metal oxide or carbonate catalysts.
Claims11
A process for preparing diorgano(poly)siloxanes of the formula (I)
- R1R2Si(OSiR2)m(OSiR22)nOH (I),
- comprising reacting hexaorganocyclotrisiloxane of the formula (II)
- (R22SiO)3 (II)
- with sil(ox)anols of the formula (III)
- R1R2Si(OSiR2)mOH (III)
- in the presence of a catalyst, and
- optionally driers, solvents, phase transfer catalysts, lithium compounds, or mixtures thereof,
- where
- R is a monovalent, unsubstituted or substituted C1-C13 hydrocarbon radical,
- R1 is a hydrogen atom or an unsubstituted or substituted C1-C13 hydrocarbon radical,
- R2 is a monovalent, unsubstituted or substituted C1-C13 hydrocarbon radical,
- m is 0 or an integer of at least 1 to 3 and
- n is an integer of 3 to 1000,
- the sil(ox)anols of formula (III) have a water content of below 1% by weight and the catalyst comprises an alkaline earth metal carbonate, alkali metal carbonate, alkaline earth metal oxide, alkali metal oxide or a mixture of two or more of these compounds.
11 more elements
Dependencies are inferred from the claim text.