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°C. The reaction follows an irreversible first‐order reaction path under pseudo first‐order kinetic conditions. The variation of pseudo first‐order rate constant (kobs) with ninhydrin concentration was found to be in agreement with equation 1/kobs = B1 + B2/[Ninhydrin]. One mol of carbondioxide evolved from decarboxylation of α‐COOH and second mol of carbondioxide comes from the decarboxylation of β‐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.