DMC COMPLEX CATALYST AND PROCESS FOR ITS PREPARATION

摘要

Process for the preparation of a DMC catalyst useful in the polymerization o f alkylene oxides into polyether polyols, which process comprises the steps of (a) combining an aqueous solution of a metal salt with an aqueous solution o f a metal cyanide salt and reacting these solutions, wherein at least part of this reaction takes place in the presence of an organic complexing agent, thereby forming a dispersion of a solid DMC complex in an aqueous medium; (b ) combining the dispersion obtained in step (a) with a liquid, which is essentially insoluble in water and which is capable of extracting the solid DMC complex formed in step (a) from the aqueous medium, and allowing a two- phase system to be formed consisting of a first aqueous layer and a layer containing the DMC complex and the liquid added; (c) removing the first aqueous layer; and (d) recovering the DMC catalyst from the layer containing the DMC catalyst.