PRODUCTION OF CARBOXYLIC ACID UTILIZING INDUSTRIAL WASTE ACID

摘要

PURPOSE:To obtain a carboxylic acid at a low cost using an industrial waste acid composed mainly of ammonium bisulfate, by mixing the waste acid with an aqueous solution of an ammonium carboxylate to produce a carboxylic acid and concentrating the by-produced aqueous solution of ammonium sulfate to recover ammonium sulfate. CONSTITUTION:Industrial waste acid composed mainly of ammonium bisulfate and produced as a by-product of ester synthesis is mixed with an aqueous solution of ammonium salt of a carboxylic acid having a pKa value of 3.3-5.5 (at 25 deg.C), more preferably with an aqueous solution of ammonium carboxylate soluble in water and separable into two phases after reacting with the above waste acid. The objective carboxylic acid can be quickly produced under mild condition in nearly quantitative yield. The by-produced aqueous solution of ammonium sulfate is concentrated to recover ammonium sulfate. Carboxylic acid useful in industrial field and ammonium sulfate useful as a fertilizer can be economically produced by fully utilizing the properties of the waste acid as an acid. At the same time, production of esters can be increased without increasing the production of waste acid.