Department of Chemistry, C. Abdul Hakeem College (Autonomous), Melvisharam-632 509, Tamilnadu, India E-mail : smansoors2000@yahoo.co.in Department of Chemistry, Periyar Government Arts College, Cuddalore-607 001, Tamilnadu, India Department of Chemistry, Thiruvalluvar University, Serkadu, Vellore-632 106, Tamilnadu, India Manuscript received online 23 October 2014, accepted 11 June 2016 Kinetics of oxidation of 4-oxo-4-phenyl butanoic acid (4-oxo acid) by benzimidazolium fluorochromate (BIFC) in acetic acid-water medium in the presence of perchloric acid has been studied. The reaction is first order each in [BIFC], [4-oxo acid] and [H+]. The reaction has been found to be catalyzed by H+ ions. The stoichiometry of the reaction is 1 : 1 and the product of oxidation is benzoic acid. The reaction rate increased remarkably with the increase in the proportion of acetic acid in the solvent medium. The reaction rates have been determined at different temperatures and the activation parameters were calculated. The reaction failed to induce the polymerization of acrylonitrile, i.e. absence of free radicals. From the observed kinetic results a suitable mechanism has been proposed.