Abstract

India has a large perfumery industry and a worldwide market for perfumes, fragrances and cosmetic formulations. Many of these perfumery chemicals are extracted from Indian plants and hence the study of perfumery alcohols becomes relevant. The quantitative aspects of the oxidation of alcohols to the corresponding carbonyl compounds has been extensively reported. But literature survey shows relatively few reports of the kinetic and thermodynamic studies of oxidation of perfumery alcohols. This paper reports the kinetics of the controlled oxidation of 1) primary acyclic alcohols, Geraniol, Nerol and Citronellol and 2) secondary cyclic alcohols, Cyclopentanol and Cyclohexanol using N- Bromosuccinimde in alkaline medium. The oxidation was carried out under first order kinetic conditions with respect to the organic oxidant i.e. [oxidant] << alc.].

The effects of alcohol and oxidant concentrations, ionic strength and temperature on the rates of oxidation of alcohols has been studied. The thermodynamic activation parameters were determined from the change of oxidation rate of alcohol with temperature and interpreted in terms of the rection mechanism proposed for the oxidation.

Keywords:Primary acyclic alcohols; Secondary cyclic alcohols; Oxidation; N-Bromosuccinimide; Kinetics; Ionic strength; Thermodynamic activation parameters; Entropy of activation; Reaction mechanism