Kinetics of Pd(II)-Catalyzed Oxidation of Ampicillin by Using Cu(Bipy)2 2+ as Oxidant in Alkaline Medium: A Spectrophotometric Study

Abstract

The kinetic and mechanistic study of homogeneously Pd(II)-catalyzed oxidation of ampicillin by Cu(Bipy)2 2+ in alkaline medium have been conducted at 35 ± 0.1 ºC. Spectrophotometric titrations show that the stoichiometry of the reaction is 1:4 ([ampicillin]:[Cu(Bipy)2 2+] = 1:4). The first order kinetics is observed regarding [Cu(Bipy)2 2+] and [Pd(II)] however, less than unity order exhibited by [OH–]. On varying [ampicillin] and [bipyridyl], velocity of reaction remains unchanged. Reaction rate unaffected by changing ionic strength of the medium while with dielectric constant, it shows inverse relation. Various thermodynamic properties of reaction were calculated such as activation energy, activation entropy, etc. Oxophenyl acetic acid and 2-formyl-5,5-dimethylthiazolidine-4-carboxylic acid were identified as reaction product. With the help of kinetic observation, spectrophotometric data an appropriate reaction mechanism and rate law derived for aforesaid reaction.