| 摘要 |
Vinyl acetate is prepared in a stepwise process in which (A) ethylene is reacted with a recycled solution comprising an acetic acid solution of a palladium II salt catalyst, an ionizable metal acetate, a cupric salt oxidizing agent and water, the latter in a proportion of 1 to 20% by weight based on the weight of solvent components, whereby at least part of the cupric salt is reduced to cuprous salt, and vinyl acetate and acetaldehyde are formed (B) removing at least part of the vinyl acetate, (C) oxidizing cuprous salt to cupric, (D) oxidizing acetaldehyde to acetic acid, (E) removing sufficient water from the working solution to maintain production of the desired controlled yield of acetaldehyde which is sufficient to provide the acetic acid requirements after the initial change of working solution, and finally (F) employing the reoxidized working solution and acetic acid for further vinyl acetate synthesis. Equimolar proportions of vinyl acetate and acetaldehyde are preferably obtained by the adjustment of the water content and a flow diagram illustrates suitable apparatus. Palladium chloride, bromide and acetate, and the alkali metal chloro- and bromopalladites may be used, the metal acetate may be cupric, alkali metal, and alkaline earth acetates or ferric, stannic, nickel and cobalt acetates. |
