Kinetics of the Decarboxylation of Acetoacetic acid

Abstract

The decarboxylation of acetoacetic acid CH3COCH2CO2H ? CH3COCH3+CO2 and its anion have been studied in aqueous solution over a range of temperature. Although the acid decomposes approximately 50 times faster than the anion at 37°, the activation energy of the acid (23.7 kcal mole-1) is comparable with that of the anion (22.9 kcal mole-1) and the large difference in reactivity is due to an entropy effect. The significance of these results is discussed and a comparison made with other ß-keto acid decarboxylations.