Continuous process for making peroxycarboxylic acids

Abstract

An improved continuous process for making a peroxyacid having about 6 to about 20, preferably about 8 to about 16 carbon atoms and at least one peroxyacid moiety, using as starting materials the corresponding carboxylic acid and hydrogen peroxide and using sulfuric acid as a reaction medium, comprising the steps of (a) maintaining a reaction mixture having a liquid component comprising 60 to 80% sulfuric acid, 2.5 to 12.5% hydrogen peroxide, and 7.5 to 37.5% water and a dispersed solid component comprising crystals of the carboxylic acid starting material and the peroxyacid product; (b) withdrawing a first recycle stream, which is filtered to remove the solid component and entrained liquid as a filter cake, leaving a liquid filtrate which is replenished with hydrogen peroxide, cooled to a temperature below the maximum permissible reaction temperature, and reinserted into the reactor; and (c) withdrawing a second recycle stream, which is replenished with sulfuric acid and with the carboxylic acid starting material, cooled to remove the heat of dilution of the sulfuric acid, and returned to the reactor; in order to continuously produce and remove from the site of reaction a filter cake from which a relatively pure peroxyacid is extracted, while maintaining in the reaction mixture the concentrations of each substance involved in the reaction. More generally, a continuous process in which solid reaction products and liquid side products are removed from a liquid-containing reaction medium while at least a portion of the liquid in said liquid-containing reaction medium is recycled to replenish the liquid-containing reaction medium.