E.i. Dupont De Nemours and Company

Eugene D Wilhoit

Howard W Anderson

Darwin Darrell Davis

James E Matush

Eddie G Mahler

Brent G Sparks

Patrick R McAllister

Dicarboxylic acid and diamine are recovered from polyamides by hydrolysis with nitric acid, followed by separation of the dicarboxylic acid, and hydrogenation of the nitric acid, and then recovery of the diamine.

Nitric acid hydrolysis of polyamides

Copper and vanadium catalyst components are recovered and dialkyl esters of dicarboxylic acids are synthesized by precipitating the catalyst metals with an alcohol selected from the group consisting of methanol, ethanol, and isopropanol removal of the precipitate, and then heating the mixture.

Catalyst recovery and dialkyl ester synthesis

A process for the production of dodecanedioic acid by oxidation of cyclododecene using a two liquid phase system comprised of valeric acid and aqueous cerium solutions containing nitrates and bisulfates in dilute nitric acid in which ruthenium tetroxide and lower oxides are dissolved or suspended. In this process cyclododecene is fed directly into the liquid phases which are continuously mixed and contained in an electrolytic cell loop operating at greater than 1.5 v in which the cerium +3 is oxidized to cerium +4 at the anode in a continuous fashion simultaneously with the ruthenium tetroxide oxidation of cyclododecene in the valeric acid. The cerium +4 regenerates the ruthenium tetroxide--simultaneously and in parallel with the other redox reactions. The process is also applicable to oxidation of cyclohexene to adipic acid.

Process for the preparation of dicarboxylic acid

An improved process for recovery of hydrogen cyanide contained in a gaseous mixture is provided which comprises (a) contacting the gaseous mixture with an aqueous solution of an alkali metal carbonate to form an aqueous solution of the alkali metal cyanide and the corresponding bicarbonate, (b) contacting the aqueous solution of (a) with a ketone to produce a cyanohydrin-ketone mixture immiscible in the aqueous solution and a regenerate the alkali metal carbonate, separating the alkali metal carbonate solution and returning it to the gas absorption step (a) and recovering the cyanohydrinketone mixture. Alternately, the cyanohydrin in the cyanohydrin-ketone mixture of step (b) can be decomposed to the corresponding ketone and hydrogen cyanide.

Growing community of inventors

Victoria, TX, United States of America

Eugene D Wilhoit