Fe/Zn double metal cyanide (DMC) catalyzed ring-opening polymerization of propylene oxide: Part 3. Synthesis of DMC catalysts

Double metal cyanide (DMC) complexes are effective catalysts for the ring-opening polymerization of propylene oxide. These catalysts are highly active and especially useful in the synthesis of polyether polyols having low unsaturation. In this paper, a family of DMC catalysts were synthesized and developed by reaction of aqueous solution of zinc chloride and potassium hexacyanoferrate with complexing agents to form a precipitate of DMC compounds. For obtaining favorable catalyst activity, the organic complexing agents such as t-butanol and polyols were employed. The complexing agents were incorporated into the catalyst structure and were required for active catalyst. The catalytic activity of the DMC complexes was significantly dependent on the composition of catalysts, feeding way and morphology structure of the DMC catalysts. The analytical method of DMC catalysts activity was also revealed.