Poly (propylene carbonate) polyols was synthesized by the copolymerization of carbon dioxide with propylene oxide in the presence of double metallic catalyst in loop reactor.

The polyether polyols which has higher molecular weight, narrower molecular weight distribution and lower unsaturation can be prepared by using double metal cyanide (DMC) complex catalysts.

This invention relates to a new duplex metal cyanide catalyst (DMC) used in synthesizing polyether polyol with high molecular weight and low degree of unsaturation and method for making same.