Process for the production of organyloxy end-terminated polysiloxanes
AssigneeBayer Aktiengesellschaft
InventorsWilhelm Weber, Karl-Heinz Sockel
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Abstract
In the production of a triorganylsily or organodiorganylsilyl end-terminated poly-(diorganosiloxane) by reacting an .alpha.,.omega.-dihydroxypoly(diorganosiloxane) with a tetraorganyloxysilane or organotriorganyloxysilane in the presence of at least one alkali hydroxide, alkali alkoxide or alkali silanolate as a catalyst, the improvement which comprises effecting the reaction also in the presence of additionally at least one alkali metal salt which is soluble in the reactive system.
Claims2
In the production of a triorganyloxysilyl or organodiorganyloxysilyl end-terminated poly-(diorganosiloxane) by reacting an .alpha.,.omega.-dihydroxypoly(diorganosiloxane) with a tetraorganyloxysilane or organotriorganyloxysilane in the presence of at least one alkali metal hydroxide, alkali metal alkoxide or alkali metal silanolate as a catalyst, the improvement which comprises effecting the reaction also in the presence of additionally at least one alkali metal salt which is soluble in the reactive system and is selected from the group consisting of:
- a) formic acid or an optionally substituted, linear, branched or cyclic alkyl carboxylic acid or a polycarboxylic acid with 1 to 30 C atoms,
- b) an optionally substituted aromatic carboxylic acid,
- c) a semi-ester of carbonic acid of the formula R.sup.6 -O(CO)OH,
- d) an aryl or alkyl sulphonic acid of the formula R.sup.7 -SO.sub.2 -(OH) and
- e) an aryl or alkyl phosphonic acid of the formula R.sup.8 -PO-(OH).sub.2 wherein
- R.sup.6, R.sup.7, or R.sup.8 designate an aliphatic or aromatic, optionally substituted hydrocarbon group with 1 to 10 atoms.
Dependencies are inferred from the claim text.