Process for purifying and end-capping polyols made using double metal

Abstract

A process for producing an ethylene oxide-capped polyol which is essentially free of catalyst residues, wherein the polyol is produced using a double metal cyanide catalyst, which comprises after polyol formation the steps of: (a) contacting a catalyst residue(s)- containing polyol with an effective amount of an oxidant (preferably selected from the group consisting of: oxygen-containing gas(es), peroxide(s), acids, and combinations thereof) to cause said catalyst residue(s) to form insoluble residues that are insoluble in the polyol; (b) separating the insoluble residues from the polyol to provide an essentially double metal cyanide catalyst residue-free polyol; (c) treating said double metal cyanide catalyst residue-free polyol with a base to provided a base-treated polyol; (d) contacting said base-treated polyol with ethylene oxide to produce an ethylene oxide-capped polyol containing base, wherein at least a portion of the secondary hydroxyl groups on said polyol are converted into primary hydroxyl groups, and (e) separating said base from said ethylene oxide capped polyol to provide a purified ethylene oxide capped polyol. In another aspect of the invention, the catalyst residue separation step is effected after EO-capping of the polyol.