Polyether polymerization process

Alkylene oxides are polymerized in the presence of a catalyst system comprising a double metal cyanide catalyst modified with certain metal or semimetal compounds. At least one additive is present. The additive is an alkali metal salt, ammonium salt or quaternary ammonium salt of a monocarboxylic acid having up to 24 carbon atoms; monopotassium phosphate, ammonium dihydrogen phosphate or quaternary ammonium phosphate, diammonium hydrogen phosphate and quaternary ammonium phosphate or phosphoric acid. 环氧烷在催化剂体系的存在下聚合，该催化剂体系包括用某些金属或半金属化合物改性的双金属氰化物催化剂。存在至少一种添加剂。该添加剂是具有至多24个碳原子的单羧酸的碱金属盐、铵盐或季铵盐；磷酸二氢钾、磷酸二氢铵或磷酸季铵、磷酸氢二铵和磷酸季铵或磷酸。