| 摘要 |
In a process for the preparation of vinyl acetate by the oxidation of ethylene in the presence of a platinum group metal catalyst, vinyl acetate and by-product acetaldehyde in a molar ratio of 1:1 to 1:1.2 are produced in a reaction mixture which is a suspension or solution containing acetate ions, acetic acid, halide ions in a concentration of 0.18 to 0.36 gm. ions per litre of reaction mixture, the catalyst metal or a compound thereof, and which is under a superatmospheric pressure up to 20 atmospheres gauge. The acetate ion may be added or formed in situ and should preferably be of greater concentration than 0.5 gm. mol./litre. The oxidation may be by molecular oxygen e.g. in the form of air or by a redox system preferably manganic/magnanous. The ester and acetaldehyde are removed and the acetaldehyde may be oxidized to acetic acid and recycled, or the acetaldehyde oxidized in situ. |
