Catalyst for the production of polyols having lower amounts of high molecular weight tail

Abstract

This invention relates to novel double metal cyanide catalysts and to a process for the production of these double metal cyanide catalysts. These DMC catalysts can be used to prepare polyoxyalkylene polyols which have low amounts of high molecular weight tail compared polyoxyalkylene polyols prepared from DMC catalysts of the prior art.

Description

Background technique [0001] The present invention relates to an improved double metal cyanide catalyst exhibiting a lower amount of high molecular weight tail, and to a process for preparing such an improved double metal cyanide catalyst. [0002] The preparation of polyoxyalkylenepolyols involves the alkoxylation of starting compounds having active hydrogen atoms with alkylene oxides in the presence of suitable catalysts. Both basic catalysts as well as DMC catalysts have been used in these alkoxylation reactions for many years. Base-catalyzed alkoxylation involves the addition of an alkylene oxide such as propylene oxide or ethylene oxide to a low molecular weight starting compound such as propylene glycol in the presence of a basic catalyst such as potassium hydroxide (KOH). or glycerol) to form polyoxyalkylene polyols. [0003] In base-catalyzed alkoxylation reactions, propylene oxide and certain other alkylene oxides undergo competing internal rearrangements, which resu...

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Problems solved by technology

Other documents such as U.S. Patent 5,952,261 and U.S. Patent Application 2006 / 0058182 disclose the addition of cyanide-free metal salts during the catalyst precipitation step to obtain highly active catalysts effective at 30 ppm or less, but they do not Any reduction in the amount of high molecular weight tails that is disclosed or claimed to be produced during the polymerization of alkylene oxides to make polyols

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