The Dow Chemical Company

Paul D Bettge

Raymond A Plepys

Hans R Friedli

Vaughn M Nace

Van A Kent

Richard J Elwell

James P Cosman

Johnny Chavez, Jr

Randall K Whitmire

Andrew S Farnum

This invention involves several ways for improving a coalescing process for purifying a crude polyether. In one aspect, particulate zirconium dioxide is selected as a coalescing medium. In a second aspect, alkali metal catalyst is recovered and recycled to make additional polyether product. In a third aspect, a polyether stream obtained from the coalescing step is purified by stripping water in at least two phases, the first of which involves moderate conditions so that water but not allyl alcohol or higher molecular weight impurities are removed from the polyether, and the second of which involves more stringent stripping conditions. In a fourth aspect, crude polyether that is subjected to a holding period before undergoing a coalescing step is mixed with water to minimize the formation of impurities that are believed to compatibilize the aqueous and polyether phases. In a fifth aspect, the coalescing process is conducted under a non-oxidizing atmosphere.

Process for purifying polyethers

The concentration of propenyl ethers in a hydroxy-functional polyether having oxypropylene units is reduced by a process including the step of contacting the polyether with an acid ion exchange resin for a time and at a temperature sufficient for the conversion of at least some of the propenyl ethers to propionaldehyde and in the presence of sufficient water for the conversion. Optionally, the polyether is treated with an epoxy compound in an amount sufficient to reduce the acidity of the polyol.

Purified hydroxy-functional polyether compounds

Growing community of inventors

Lake Jackson, TX, United States of America

Paul D Bettge