Solvation effect and thermochemical study of some -arginine salts in polar solvent using ultrasonic velocity

The ultrasonic velocity in non-aqueous electrolytic solutions has been measured which gives valuable information regarding the nature and strength of various interactions and the formation of hydrogen bonding. It also shows the behaviour of hydrogen such as molecular association and dissociation. Solvation is the association of solvent molecules with the solute ions in a solution. In the present study, the fundamental parameters of three amino acids namely, -arginine, -arginine mono hydrochloride and -arginine methyl ester dihydrocholoride in non-aqueous solution as a function of composition in the temperature range 278.15-328.15 K have been measured. Using these experimental value solvation number and the acoustical parameters such as adiabatic compressibility, apparent molal volume and apparent molal compressibility have been calculated for all the three systems. These results are analysed and eventually emphasizing the possible molecular interactions in terms of structure-making and structure-breaking effects of the above amino acids in the solvent. (author)