Recovery of siloxane cycles
OwnerWilfried KNOTT, Horst DUDZIK +1inventors
InventorsWilfried KNOTT, Horst DUDZIK, Frauke HENNING
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Abstract
The present invention provides a process for depolymerizing waste silicones to afford siloxane cycles, wherein the process comprises a first step of reacting the waste silicone with at least one alcohol and at least one alkali metal alkoxide without removing any potentially occurring water from the reaction mixture, subsequently neutralizing the reaction mixture, removing the solid constituents and then distillatively removing the optionally previously added solvent and excess alcohol and subsequently heating the obtained alkoxysiloxane with at least one fatty alcohol and at least one alkali metal alkoxide with mixing and distillatively removing the siloxane cycles formed.
Claims21
1-15. (canceled)
A process for depolymerizing waste silicones to provide siloxane cycles, wherein the process comprises:
- (a) creating a reaction mixture by mixing at least one waste silicone with at least one alcohol and at least one alkali metal alkoxide with heating but without either the use of inert solvents which are water-insoluble but form azeotropes with water and/or without the use of further dehydrating agents;
- (b) neutralizing the reaction mixture of step a) using at least one Brønsted acid, removing, any solid constituents present, and then distillatively removing any previously added solvent and excess alcohol present in step (a) from the alkoxysiloxane(s) produced;
- and
- (c) heating the alkoxysiloxane(s) of step b) with at least one fatty alcohol and at least one alkali metal alkoxide by mixing and thermally removing the siloxane cycles formed.
Dependencies are inferred from the claim text.