KINETICS AND MECHANISM OF OXIDATION OF SOME ORGANIC COMPOUNDS BY PEROXIDISULPHATE ION

Abstract

The search for information about the changes which compounds undergo is the very essence of chemistry, not only because of the end products formed but also in view of the intermediates and the transformations which control the overall reaction. Investigations of the mechanism of reactions have, therefore, been undertaken since the beginning of modern chemistry. Information on rates and mechanisms of the reactions is most valuable in guiding operations and choosing optimum conditions for synthesis as well as for analytical work. The study of the mechanism of redox reactions is a subject of considerable importance, for not only does it require consideration of the properties and reactions of both inorganic and organic compounds, but it has vast implications in understanding the nature of life. The Malthusian growth of the world's population, while more talked about, is not more striking that the concurrent expansion of the knowledge In the field of chemical kinetics. The rate of chemical reactions and the pathways by which they occur are fundamental facets of chemistry. Reaction kinetics has created equal interest in all chemists throughout the world. Kinetic study coupled with other techniques provides one of the most satisfactory ways of obtaining information about the mechanism and pathways involved, in the reaction. Furthermore, the course and products of a large number of organic reactions are controlled by the relative rates of several competing steps and only kinetic study can predict the conditions required for favouring a desired product. Thus its study is fruitful in two ways for organic chemists, firstly, to investigate the intricacies hidden inside the reaction and secondly the favourable conditions for obtaining the desired product on commercial scale. In some cases it is not possible to provide complete and entire information about the course that is traversed by any chemical reaction. Sufficient data can, nevertheless, often be gathered to show that one mechanism is more likely than another. The common oxidising agents used for oxidising organic compounds are potassium permanganate and potassium dichromate but these are strong oxidising agents, and with them the intermediate products of oxidation can rarely be separated and identified. The use of peroxydi sulphate ion as an oxidant is comparatively recent. The redox potential of the system S2°8* + 2e" * 2S°4" is 2.01 volts1. Kinetic studies involving the use of peroxy di sulphate ion may be categorised as follows: 1. Self decomposition of peroxydisulphate ion, 2. Reactions with inorganic reductants.