Conductometric studies on solvation behaviour of tartaric acid in various solvent mixtures

The paper deals with the investigations made on the ion-solvation behaviour of tartaric acid in different compositions (v/v) of water+methanol/ethanol/DMSO/DMF/dioxan mixtures between 288 to 313 K, using electrical conductivity principle. The electrical conductance data were analysed by Kraus-Bray and Shedlovsky model of conductivity. The limiting molar conductance, lambda(m)(0) sharply decreased for the increased amount of co-solvent until 80% suggesting the increased ion-solvent and solvent-solvent interactions. Association constant, K-a has been computed in all the cases. In water+MeOH/EtOH mixtures the K-a increased with increase in temperature suggesting endothermic behaviour of the system. Walden product, Stoke's molecular radius and thermodynamic parameters related to association and solvation have been determined using Born model in all the cases of solvents mixtures. The energy of activation was also calculated and was found to be the highest in the case of water+ethanol. (C) 2003 Elsevier B.V. All rights reserved.