GB765334A - Process for separating ethyl acetate from liquid mixtures by extractive distillation - Google Patents

Abstract

Ethyl acetate is separated from complex liquid mixtures by passing the vapours of the mixture up a fractionating column while introducing into the upper part of the column an auxiliary liquid which both extracts the ethyl acetate (thereby washing the ethyl acetate down the column) and in part distils azeotropically from the head of the column with at least one other component of the mixture. The process is particularly applicable to mixtures containing ethyl acetate, water and ethanol; in this case an auxiliary liquid is chosen which forms an azeotrope with water. Auxliary liquids referred to are:- butyl acetate, amyl acetate, dibutyl ether, xylene, and chlorinated hydrocarbons. A mixture comprising ethyl acetate (92.3 per cent), water (3.6 per cent) alcohol (2.4 per cent) and acetone (1.7 per cent) is distilled in a column (3 metres high and 4 cms. wide), and butyl acetate is introduced into the top of the column. The mixture which collects at the base of the column contains butyl acetate and about 98.7 per cent of the ethyl acetate present in the original mixture. The remaining components pass overhead in the vapour state together with butyl acetate. The overhead vapours are condensed; and the condensate is allowed separate into two liquid layers, which are decanted. The upper layer consists mainly of butyl acetate, while the lower layer consists mainly of water. The two layers are submitted separately to fractionation in order to separate the more easily volatile constituents from the butyl acetate and from the water. The combined distillates (which amount to about 6 per cent of the original mixture) contain ethyl acetate (36.9 per cent), water (10.8 per cent), acetone (21.5 per cent) and alcohol (30.8 per cent); and is worked up in the usual manner.