E.i. Dupont De Nemours and Company

Suriyanarayanan Dorai

Richard E Ernst

Dhiren V Patel

James R Cavall

William W Goudie

Sarah E Ochsenhirt

Polyether glycols, especially poly(tetramethylene ether) glycols, having a narrow molecular weight distribution (e.g., Mw/Mn=1.2 to 1.80), are made by a process which consists of separating the low molecular weight fraction in an ultrafiltration module. In these units, molten PTMEG is fed at temperatures in the range of 30.degree. to 150.degree. C. and pressures ranging between 25 and 1500 psi. The PTMEG retentate from the ultrafiltration unit is also characterized by water content &lt;25 ppm and low to negligible concentration of oligomeric cyclic ethers.

Reducing molecular weight polydispersity of polyether glycols by

An improved method for recovering purified poly(tetramethylene ether) glycol or similar polyether polyol from an aqueous solution of polymer containing an alkaline metal catalyst residue involving the addition of a stoichiometric excess of magnesium sulfate or sulfite followed by evaporation of water and separation of molten polymer from precipitated solid phase (i.e., from magnesium hydroxide, alkaline metal sulfate/sulfite, and excess magnesium sulfate/sulfite). Such a process results in essentially complete removal of any basic transesterification catalyst and water without significant lost of poly(tetramethylene ether) glycol or the like.

Method for removing transesterification catalyst from polyether polyols

A process for preparing a narrow molecular weight distribution poly(tetramethylene ether) glycol (PTMEG) from a PTMEG starting material via liquid-liquid extraction which employs methanol, water and non-polar solvent wherein the amount of non-polar solvent is, by weight, less than the PTMEG starting material.

Process for preparing a narrow molecular weight distribution poly

A process for reducing fluoride levels in PTMEG by heating aqueous PTMEG having an undesired level of fluoride (80'600 ppm) to a temperature in the range between about 200.degree. and 300.degree. C. for a period of time sufficient to reduce the fluoride content of said PTMEG. Preferably, heating is carried out with agitation to a temperature between about 225.degree. and about 275.degree. C. for about 1 minute to about 8 hours in the presence of an aqueous base, most preferably 240.degree. to 250.degree. C. in presence of aqueous lime.

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Lockport, NY, United States of America

Suriyanarayanan Dorai