| 摘要 |
In a process for the catalytic oxidation of propylene in the presence of ammonia and oxygen, acrylonitrile is separated from the raw product which has a pH in the range 5-7, by a distillation process. The raw product is worked with 10-20% alkali solution, e.g. sodium, potassium or alkaline earth hydroxides, in one or more steps, batchwise or countercurrently and then by water or a dilute mineral acid such as sulphuric acid. A preliminary distillation before the alkaline wash may be included. The pH of the feed to the distillation is adjusted to a pH 5-7 and inhibitors such as p-t-butyl catechol, hydroquinone-mono-benzyl or -monomethyl ether are added. Atmospheric or slightly reduced pressure is used and a water azeotrope is distilled off in a first stage followed by pure acrylonitrile in a second stage. |
