Studies in oxidation

The kinetics of the oxidation of toluene and its ring-substituted derivatives as well as of diphenyl methane by chromic acid have been studied in acetic acid-water systems. The reaction had to be in unbuffered solutions to get a measureable rate. Product analysis showed a step-wise reaction. Rate constants have been evaluated, using a graphical method, for a three-stage consecutive and concurrent reaction, the values being obtained for the first and last stages alone. Electron attracting substituents retard the reaction while those facilitating electron release accelerate the reaction. Diphenylmethane also undergoes only a step-wise reaction with the second step much slower than the first. A comparison of experimental activation energies indicates clearly that the entropy term of the rate equation exerts possibly an even greater influence on the reaction.