Texaco Chemical Company

Huntsman Specialty Chemicals Corporation

William Pleasant Nelson

Mark E Taylor

William A Smith

In the purification of an aqueous acetone-contaminated propylene oxide feedstock in an extractive distillation column in the presence of an oxyalkylene glycol extractive distillation agent under distillation conditions selected to promote the formation and maintenance of an acetone buffer in the distillation column, a higher boiling (heavier) distillation fraction containing substantially all of the oxyalkylene glycols, water, and acetone introduced into the extractive distillation column is continuously withdrawn and the higher boiling (heavier) distillation fraction is partially vaporized in a first reboiler; the remaining liquid being partially vaporized in a second reboiler and the vapors being recycled to the extractive distillation column.

Use of paired reboilers in the purification of propylene oxide by

An extractive distillation agent consisting essentially of a mixture of triethylene glycol with a lower boiling cosolvent selected from the group consisting of 2-methyl-2,4-pentanediol, tertiary butyl alcohol and ethylene glycol is fed to an extractive distillation column used for the distillation of propylene oxide contaminated with water, acetone and methanol to obtain an overhead distillate fraction consisting of essentially anhydrous propylene oxide contaminated with reduced quantities of acetone and methanol, and a heavier bottoms distillation fraction containing substantially all of the extractive distillation agent, water and acetone and some of the methanol introduced into the distillation column.

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Nederland, TX, United States of America

William Pleasant Nelson