Oxidation process

Abstract

Rapid temperature rises which characterize carbohydrate-nitric acid oxidation reactions used to form carbohydrate-derived acids may be moderated and temperature control readily maintained by blowing a gas such as air, oxygen, nitrogen or the like into the reaction mixture as needed to control the temperature of the reaction. The more moderate reaction conditions afford higher yield of the desired product with a concomitant reduction of byproducts which may be difficult to remove and usually are unwanted as well. Upon completion the oxidation mixture is made basic (e.g. with an alkali metal base hydroxide or carbonate, ammonia or an amine) to a pH at which the the carboxyl group or groups of the product carbohydrate-derived acid are entirely in the salt form. The aqueous solution is then passed through an ion retardation resin column to recover the carbohydrate-derived salt, using water as the eluent. If desired, the carbohydrate-derived acid salt may then be recovered easily by removal of solvent water or by precipitation by addition of an water-miscible organic compound such as methanol, ethanol, acetone, isopropanol, etc.).