Reducing oxazole content of acrylonitrile - by scrubbing, distn. combining side-stream with scrubbing water and expelling oxazole with residual gas

摘要

Acrylonitrile having a low oxazole content is prepd. by scrubbing the gaseous reaction mixt., leaving the reactor, with water, in an absorption column, (A), and distilling the absorption soln. in a solvent extn. column, (B) to recover crude acrylonitrile while an oxazole-rich side-stream is removed from column bottom. Novelty consists in removing a gaseous side-stream from the distn. section of the solvent extn. column (B) and combining it with the scrubbing water charged to the absorption column head (A). The oxazole present in the scrubbing water is expelled, from column head, by means of the residual gas and discharged with it. Oxazole and isoxazole content can be reduced to 5 ppm, e.g. 2-3 ppm, compared with 100 ppm without removing the gaseous side-stream. MeCN content can be reduced simultaneously to =1 ppm.