A Study on the Solute-Solute and Solute-Solvent Interactions of some Tetraalkyl-ammonium Perchlorates in Aqueous Binary Mixtures of 2-Methoxyethanol from their Partial Molar Volume Data

Department of Chemistry, North Bengal University, Darjeeling-734 430 Manuscript received 15 February 1995. accepted 25 July 1995 The apparent molar volumes of four symmetrical tetraalkylammonium perchlorates (Me4NClO4, Et4NCIO4, Pr4NClO4 and Bu4NCIO4) have been determined in 2-methoxyethanol (ME)+ water mixtures containing 20, 40,60 and 80 mass% of 2-methoxyethanol at 25º. The apparent molar volumes are extrapolated to zero concentration to obtain the limiting values at infinite dilution. Ionic limiting partial molar volumes have been estimated using the extrapolation method. Ion-ion interactions are found to be very weak but increase with Increasing amount of 2-methoxyethanol in the solvent mixtures. The results have been explained on the basis of the electrostriction effect of the perchlorate ion and the hydrophobic and size effects of the tetraalkylammonium ions