Kinetics and Mechanism of Oxidation of Some α -Hydroxy Acids by Pyridinium Dichromate in Aqueous Acetic Acid Medium Ahmed S. Zaheer1, Shafi S. Syed2, Mansoor S. Sheik3 1Department of Chemistry, Islamiah College, Vaniyambadi – 635 752, Tamil Nadu, India 2Department of Chemistry, Thiruvalluvar University, Serkadu, Vellore – 632 106, Tamil Nadu, India 3Department of Chemistry, C. Abdul Hakeem College, Melvisharam – 632 509, Tamil Nadu, India *Corresponding Author E-mail: prof.zaheerahmed@gmail.com
Online published on 7 February, 2013. Abstract The Kinetics and mechanism of oxidation of some α hydroxy acids by pyridinium dichromate (PDC) has been studied by spectrophotometric method in 50% acetic acid -50% water (v/v) medium at 303K. Under the conditions of pseudo first order, the reaction follows first order kinetics with respect to hydroxy acid, [H+] and [PDC]. The reaction is catalysed by perchloric acid. There is no salt effect. The rate increases with increase in the percentage of acetic acid and the plot of log Kobs Versus 1/D is linear with a positive slope indicating the ion-dipole nature of the reaction. Activation parameters have been evaluated. Based on the experimental results, a suitable mechanism has been proposed. Top Keywords Pyridinium dichromate, hydroxy acids, kinetics, oxidation, perchloric acid. Top |