Process for preparing a catalyst

摘要

A process for making substantially non-crystalline double metal cyanide (DMC) catalysts having improved activity and performance is disclosed. The process comprises using a metal salt having an alkalinity within the range of about 0.2 to about 2.0 wt. % as metal oxide based on the amount of metal salt to prepare the catalyst. Surprisingly, important polyol properties such as viscosity and unsaturation improve when the alkalinity of the metal salt used to make the DMC catalyst is properly controlled. The process allows catalyst producers to enjoy the benefits of substantially non-crystalline DMC catalysts even when relatively inexpensive, technical-grade metal salts are used to make the catalyst.