GB368348A - Improvements in or relating to the manufacture of acetic acid - Google Patents

Abstract

In the oxidation of liquid acetaldehyde by air or oxygen for the production of acetic acid, the concentration of the acetic acid in the reaction mixture is maintained at a point not exceeding 70 per cent; for instance, it may be maintained at 50-70 per cent by additions of acetaldehyde. A known catalyst may be used, such as manganese acetate, uranium oxide, ferric oxide, ferric acetate, chromium oxide, vanadium pentoxide, or the catalysts described in Application 367,863 (manganic salts) or in Specifications 154,304 and 154,680, [both in Class 2 (iii), Dyes &c.] (china clay or kaolin or the residue left on calcining animal charcoal or mixtures thereof with sodium acetate), and normal, reduced, or increased pressure may be employed. The oxidizing gas may be introduced in fine bubbles, with agitation and the temperature may be from 0 to 40 DEG C. or more. Cooling to 0-5 DEG C. may be employed advantageously during the initial stages and/or intermittently during the process. The reaction vessel may be provided with a condenser, and the escaping gas may be scrubbed with acetic acid or with some of the reaction liquor, and the liquor returning to the reaction vessel may do so in the form of spray. Catalyst may be added with the aldehyde continuously or intermittently. The acid may be freed from aldehyde by heating or fractionation and further distilled with or without permanganate. Specification 366,022 also is referred to.