Semi-refined mixed dicarboxylic acids

Abstract From the Canadian patent

A process is disclosed for recovering a semi-refined mixture of adipic, glutaric and succinic acids from an aqueous mixture comprising the acids together with catalyst residues and impurities. The process comprises the steps of: (a)adding to the aqueous mixture a reducing agent consisting essentially of hypophosphorous acid or sodium hypophosphite (b)concentrating the resulting aqueous mixture to remove water to produce a substantially dehydrated mixture; and (c)feeding the substantially dehydrated mixture to an evaporator and evaporating therefrom a mixture of adipic, glutaric and succinic acids. The mixture of adipic, glutaric and succinic acids may then be condensed as a molten material …