Process for the isolation of vinyl acetate

摘要

The invention relates to a process for the isolation of vinyl acetate from a gas mixture containing vinyl acetate, ethyl acetate, water and carbon dioxide formed in the reaction of ethylene with acetic acid and oxygen in the gas phase over catalysts containing palladium or palladium compounds. The gas mixture leaving the reaction zone is passed into a distillation column and the gas mixture leaving the top thereof is cooled. The gas which is not condensed during the cooling is washed with acetic acid in a washing column, an acetic acid solution containing vinyl acetate being obtained. The bottom product from the distillation column is passed to a second distillation column and a side stream containing ethyl acetate is removed from an enrichment zone above the bottom thereof, all or some of the bottom product from the second distillation column, which product chiefly consists of acetic acid, being used for the wash in the washing column. The top vapor of the second distillation column is cooled. A portion of the organic phase of the condensate thereby formed is passed, together with the acetic acid solution obtained as the bottom product in the washing column, into a third distillation column, which may have an intermediate tray. The bottom product of the third distillation column is passed into a fourth distillation column. Pure vinyl acetate is removed at the top of the fourth distillation column.