SOLVENT CLASSIFICATION BASED ON SOLVATOCHROMIC PARAMETERS - A COMPARISON WITH THE SNYDER APPROACH

Solvents play a major role in many chemical processes. Their effect is closely related to the nature and extent of solute/solvent interactio ns, developed locally in the immediate vicinity of the solutes, A new generation of empirical parameters helps to describe the solvent featu res in these microscopic environments, Their adequacy for the establis hment of linear free energy relationships (LFER) has been widely prove d. A classification scheme based on the microscopic properties of solv ents is proposed, to provide a clearer insight into the solvent-space structure in terms of the similarity of solute/solvent interactions an d to help chemists in the choice of a suitable solvent for each purpos e. The Kamlet and Taft solvatochromic parameters alpha, beta and pi h ave been selected as microscopic solvent descriptors, and solvent grou ps have been designed according to the results obtained from the appli cation of several multivariate clustering techniques. The present sche me is compared with Snyder's triangle, an earlier solvent representati on used extensively in chromatography. Analogies and differences which arise from the field of application and from the solvent descriptors used in each classification scheme are discussed.