Solvation studies of some alkyl substituted ammonium salts in binary mixtures of acetonitrile with dimethylsulfoxide and dimethylacetamide

Abstract

This thesis work deal with the synthesis of mono alkylammonium perchlorates comprising of homologous series of alkylammonium cations (RNH3 +) and anion like perchlorate (ClO4-). A systematic study has been carried out to elucidate various physicochemical and thermodynamic properties of substituted alkylammonium perchlorate in acetonitrile-dimethylsulfoxide (AN+DMSO) and acetonitrile-N, N-dimethylacetamide (AN+DMA) binary mixtures at 298 K, 308 K, 318 K and 328 K. From the results obtained, it can be inferred that, there exists solvent-solvent, solute-solvent and inter molecular interactions in these solution systems, which depend upon the nature of electrolyte, solvent composition i.e. (nature of co-solvent viz. DMSO and DMA to AN). AN+DMSO and AN+DMA mixtures show quite similar results with regard to ultrasonic velocity, density, viscosity data and derived acoustical parameters, though some minor changes have also been observed for excess function calculations. AN+DMA solvent system exhibit a deviation more towards a stronger interaction mode as compare to AN+DMSO solvent system. From all the studied parameters, it was concluded that investigated RNH3ClO4 and RNH3 + ion indicate the presence of stronger ion-solvent interactions in AN+DMSO mixtures than those for AN+DMA mixtures at the experimental temperatures. Conclusively, it could be said that the interpretation of the results obtained is consistent with the existence of stronger molecular association such as hydrogen bonding, ion-dipole, dipole-dipole or dipole-induced dipole interaction, at 60 mol% DMSO in the AN+DMSO solvent system at 298 K. The conclusions drawn from compressibility, expansibility, conductance, viscosity and derived thermodynamic parameters are thus found in good agreement with each other. newline