Abstract: In the manufacture of adipic acid by nitric acid oxidation of cyclohexanol and cyclohexanone glutaric and succinic acids are recovered from the reaction by-product and waste stream by crystallizing adipic acid and succinic acid out of the stream leaving glutaric acid in the residue; forming succinic anhydride from the succinic acids so obtained; separating the succinic anhydride from the adipic acid by distillation thereby to recover succinic acid in anhydride form; and crystallizing, thereby to recover, the glutaric acid from the residue.

Abstract: An improvement in an electrolytic hydrodimerization process for hydrodimerizing an olefinic compound such as acrylonitrile to form a dimerized product such as adiponitrile in which an aqueous electrolyte solution comprised of the olefinic compound, a directive salt (providing quaternary ammonium cations) and a conductive salt is electrolyzed in a reaction cell, the aqueous solution is purged from the reaction cell, and subjected to a series of steps involving the recovery of the product, the directive salt and the conductive salt, the recovered salts being used to reconstitute the aqueous solution, the improvement being a functionally coordinated evaporation step which permits a higher rate and more efficient recovery of product and salts, a higher purge rate and a substantially higher yield of the dimerized product. The invention also constitutes an improved electrolyte recovery process.