The decarboxylation of itaconic acid polymers

Itaconic acid polymers decarboxylate in aqueous solution at temperatures of 100°C or less. The molar amount of evolved carbon dioxide per itaconic unit increases with itaconic acid content to about 0.30 for homopolymers. Development of ultraviolet absorption accompanies decarboxylation. A condensation of adjacent itaconic units which results in β‐keto acids capable of decarboxylation to cyclic ketones is proposed. Further condensation may result in β‐diketones. These reactions of polyitaconic acid are consistent with a structure consisting of repeating itaconic acid units. Polymaleic acid decarboxylates under similar conditions with the evolution of about 0.15 mole of carbon dioxide per maleic unit.