Vinyl acetate recovery by extractive distillation - from mixts with methanol, methyl acetate and acetaldehyde

摘要

The extractive distillation is carried out using an extracting agent of b.pt. 100 degrees C. consisting of a benzene or naphthalene hydrocarbon (deriv.), whereby in a first stage the mixt. of vinyl acetate, methanol, methyl acetate, and acetaldehyde, opt. contng. a little water, is sepd. into a top prod. consisting of methanol, methyl acetate, acetaldehyde and small amts. of extracting agent and vinyl acetate, and a bottom prod. consisting of extracting agent and vinyl acetate, and in a second stage the bottom prod. is sepd. by distillation into vinyl acetate as top prod. and extracting agent as bottom prod. Prefd. extracting agents are e.g. 1,2,4-trimethylbenzene, chlorobenzene, o-dichlorobenzene and nitrobenzene. The process is esp. useful for treating solns. resulting from polymsn. of vinyl acetate in methanol soln. and gives vinyl acetate of high purity with very low aldehyde (polymsn. inhibitor) content.