Acetic acid; Ethylene

vinyl acetate

To produce vinyl acetate starting from ethylene, acetic acid and oxygen using a continuous gas phase process.

Description: Vaporized acetic acid and ethylene are mixed with oxygen and reacted in a fixed bed tubular reactor (1). Supported noble metal catalysts are used that yield high average selectivities of 92% over the whole service time. There is a choice of several types of catalyst, depending on the size and location of the plant. The only major byproduct is CO2. Steam is generated (2) from the reactor by the exothermic heat of reaction and used in the purification train.
   Purification: Vinyl acetate is recovered from the reaction gas mixture by condensation and scrubbing (3). Unreacted ethylene is recycled to the reactor after removing CO2 in a standard hot carbonate system (4,5). The crude vinyl acetate is purified by distillation (6) from acetic acid which also is recycled, from water, light ends (mainly acetaldehyde) and heavy ends. Safe operation with respect to fouling, corrosion and the explosion limit of the reaction gas is ensured by extensive experience. All environmental protection requirements can be met. The process has been jointly developed by Bayer AG and Hoechst AG. Process economics have been continuously improved and optimized.

Component Names and Formula