Abstract: An extractive distillation agent consisting essentially of 1-methyl-2-pyrrolidone 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 1-methyl-2-pyrrolidone, water and acetone and some of the methanol introduced into the distillation column.