KINETICS AND MECHANISM OF DECARBOXYLATION OF ASPARTIC-ACID WITH NINHYDRIN

The kinetic study of the decarboxylation of aspartic acid has been carried out at various [ninhydrin], [H+] and at different temperature ranging from 60-95-degrees-C. The reaction follows an irreversible first-order reaction path under pseudo first-order kinetic conditions. The variation of pseudo first-order rate constant (k(obs)) with ninhydrin concentration was found to be in agreement with equation 1/k(obs) = B1 + B2/[Ninhydrin]. One mol of carbondioxide evolved from decarboxylation of alpha-COOH and second mol of carbondioxide comes from the decarboxylation of beta-keto acid which is an intermediate and formed during the course of ninhydrin and aspartic acid reaction. On the basis of the observed data, a possible mechanism has been proposed.