Highly active double metal cyanide complex catalysts

A zinc hexacyanocobaltate complex catalyst which comprises zinc hexacyanocobaltate, tert-butyl alcohol, and zinc chloride, wherein the catalyst contains less than about 0.2 moles of zinc chloride per mole of zinc hexacyanocobaltate.

A method of making a highly active DMC complex catalyst, said method comprising reacting aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent, wherein the metal salt is used in an excess amount less than a 100% stoichiometric excess relative to the amount of metal cyanide salt, and the resulting catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound in the catalyst.

A method of making a highly active DMC complex catalyst, said method comprising:

• (a) reacting aqueous solutions of a metal salt and a metal cyanide salt in the presence of an organic complexing agent to produce a catalyst precipitate, said metal salt being used in excess compared with the amount of metal cyanide salt used;
• and
• (b) washing the catalyst precipitate with a mixture of water and organic complexing agent in a manner effective to produce a highly active DMC complex catalyst that contains less than about 0.2 moles of the metal salt per mole of DMC compound in the catalyst.