Evonik Operations Gmbh

André Brötzmann

Wilfried Knott

Horst Dudzik

Michael Fiedel

Philippe Favresse

Michael Ferenz

Frauke Henning

Dagmar Windbiel

Jan Caßens

Phillippe Favresse

Jan Cassens

The invention describes (i) reaction systems for the production of siloxanes bearing acetoxy functions, comprising a) silanes and/or siloxanes bearing alkoxy groups and/or b) silanes and/or siloxanes bearing acetoxy groups, c) silanes and/or siloxanes bearing hydroxy groups, d) optionally simple siloxane cycles and/or DT cycles, e) a reaction medium, comprising acetic anhydride, perfluoroalkanesulfonic acid and preferably acetic acid, (ii) a process for producing linear or branched siloxanes bearing acetoxy functions and also the use of same for producing polyethersiloxanes.

Reactive siloxanes

Branched SiOC-linked polyethersiloxanes have the following formula (I) where Ris an alkyl radical having 1 to 4 carbon atoms or a phenyl radical, but preferably 90% of the radicals Rare methyl radicals; b has a value of from 1 to 10; a has a value of from 1 to 200, preferably 10 to 100, a value of from 3 to 70 when b is &#x2265;1 and &#x2264;4, or a value of from 3 to 30 when b is &#x3e;4; and Rdenotes identical or different polyether radicals, but at least one radical Ris a structural element radical of formula (II): where p=at least 2, preferably p=2-6, particularly preferably p=3.

SiOC-based polyethersiloxanes

SiOC-based polyethersiloxanes are prepared based on linear &#x3b1;,&#x3c9;-hydroxy group-bearing siloxanes. In a first step, &#x3b1;,&#x3c9;-acetoxy group-bearing linear polysiloxanes are prepared. In a second step, the &#x3b1;,&#x3c9;-acetoxy group-bearing linear polysiloxanes are converted into the desired organosiloxane units, preferably shorter organosiloxane units, wherein the thus converted organosiloxane units have &#x3b1;,&#x3c9;-acetoxy groups. In a third step, the &#x3b1;,&#x3c9;-acetoxy group-bearing linear polysiloxanes from step 2 react with polyetherols to give SiOC-based polyethersiloxanes.

Tailored SiOC-based polyethersiloxanes

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Essen, Germany

André Brötzmann