THERMAL DECARBOXYLATION OF URONIC ACIDS

Abstract

A novel decarboxylation of uronic acids by merely heating the material without the use of a solvent or added catalyst is described. At approximately 255 °C. decarboxylation for uronic and polyuronic acids and salts within 15 min. reaction time is nearly quantitative. Vigorous dehydration occurs simultaneously, the residue corresponding basically to a 5-carbon skeleton that contains 1.5 atoms of oxygen. Other products of the reaction are minor and include carbon monoxide, and traces of acid and oils. Sugar acids, such as gluconic and ascorbic, are not as extensively decarboxylated. The reaction is employed for analysis of several nitrogen dioxide oxidized celluloses and starches and the results are in good agreement with those given by titration and the 12% hydrochloric acid method.