| 主权项 |
1. A process for the separation of vinyl acetate from a gas mixture formed by the reaction of ethylene with acetic acid and oxygen in the gas phase over catalysts comprising palladium or palladium compounds comprising:
a) introducing said gas mixture leaving a vinyl acetate reactor into a predewatering column, b) cooling a gas mixture leaving the top of the predewatering column below 85° C. in a countercurrent heat exchanger, c) further cooling a gas mixture or a gas and liquid mixture leaving the heat exchanger in step b) to from −20 to 50° C. to form a condensate that separates into an aqueous phase and an organic phase, d) taking off the aqueous phase formed in step c), e) recirculating all or part of the organic phase formed in step c) as reflux to the top of the predewatering column utilized in step a) and taking off part of the organic phase which is not used as reflux, f) scrubbing a gas comprising vinyl acetate which is not condensed in step c) in a gas scrubbing column by means of an aqueous acetic acid solution, g) isolating the vinyl acetate, h) heating recycle gas leaving the gas scrubbing column, optionally together with fresh ethylene and/or recycle gas coming from a CO2 removal system and/or flash gas, in the countercurrent heat exchanger, with the gas mixture leaving the top of the predewatering column, and thereby reducing the temperature of the gas mixture leaving the top of the predewatering column, and i) introducing the heated recycle gas optionally together with the fresh ethylene and/or the recycle gas coming from the CO2 removal system and/or the flash gas preheated in step h), into the vinyl acetate reactor. |
