El Paso Products Company

Samuel S Mims

In one of its embodiments this invention provides a process for recovering C.sub.4 -C.sub.6 dicarboxylic acid components contained in a waste byproduct stream derived from a reaction system in which adipic acid is produced by nitric acid oxidation of cyclohexanone/cyclohexanol. An important aspect of the process is the esterification and extraction of the C.sub.4 -C.sub.6 dicarboxylic acids in the aqueous byproduct stream with a mixture of C.sub.1 -C.sub.3 alkanol and C.sub.6 -C.sub.20 alkanol, and the subsequent recovery of di(C.sub.6 -C.sub.20 alkyl) esters of succinic acid, glutaric acid and adipic acid. In a broader aspect this invention provides a process for recovery of water miscible organic acid components contained in an aqueous solution as C.sub.6 -C.sub.20 alkyl esters of the organic acids.

Recovery of water miscible organic acids from aqueous solution as alkyl

Organic acids contained in aqueous solution are separated and/or recovered by a process comprising adding an alcohol to the aqueous solution to esterify the acids present, while preferably simultaneously contacting the alcoholic mixture with a water-immiscible solvent and separating layers into an aqueous phase and an organic phase, whereby extraction with the water-immiscible solvent shifts the equilibrium toward the formation of more esters. The esters of the acids may than be recovered as by distillation.

Esterification and extraction process

Treatment of aqueous nitric acid solutions resulting from the nitric acid oxidation of cyclohexanol and/or cyclohexanone in the presence of metal compound oxidation catalysts for recovery of the valuable components contained therein, which comprises adding an alcohol to the aqueous nitric acid solution to esterify the acids present, contacting the resultant alcoholic mixture with a water-immiscible solvent, separating layers into an aqueous phase and an organic phase, treating the aqueous phase to recover the nitric acid and catalyst components and treating the organic phase to recover the acid derivatives.

Process for treatment of adipic acid mother liquor

Complex mixtures of polycarboxylic organic acids and their precursors, such as the by-products from the air oxidation of cyclohexane and its derivatives, are treated with nitric acid under hydrolytic conditions, esterified with an alcohol, extracted with an immiscible solvent such as benzene, the extraction preferably being carried out simultaneously with esterification, and separated into component diesters.

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Odessa, TX, United States of America

Samuel S Mims