| 摘要 |
<p>Highly active double metal cyanide (DMC) complex catalysts which, unlike other highly active DMC catalysts, are substantially crystalline, comprise a DMC compound, an organic complexing agent, and a metal salt, wherein the catalyst contains less than about 0.2 moles of the metal salt per mole of DMC compound. The catalysts may be formed by 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. Alternatively the aqueous solution may be reacted with the metal salt in excess to form a catalyst precipitate and the precipitate then washed with water and complexing agent to produce the catalyst product. Polyether polyols made from the catalysts have low unsaturation and are useful for making many types of polyurethane products.</p> |
