PURPOSE: To prepare an alkoxylating catalyst by mixing calcium metal or a calcium-contg. compd. with an activator having a specified compsn. and reacting the produced compsn. with an oxyacid or a multi-valent metallic salt under specified conditions.

CONSTITUTION: Calcium metal or a calcium-contg. compd. is mixed with an activator expressed by the formula I (X and Y denote each oxygen, nitrogen, sulfur or phosphorus, (a) and (b) denote each an integer which satisfies a valency requirement, Q is an electrically positive or neutral org. group corresponding to X or Y, Z and Z' denote each hydrogen or an org. group which does not interfere reaction or solubilization), to make react or dissolve at least partly and obtain a calcium-contg. compsn. having a titration alkalinity. The compsn. is reacted with one or more di-valent or multi-valent metallic salt of oxyacid under specified conditions, to prepare an alkoxylating catalyst.