Electrical Conductivity Studies of 1-Butyl-3-methylimidazolium Salicylate as an Active Pharmaceutical Ingredient Ionic Liquid (API-IL) in Aqueous Amino Acids Solutions

Abstract

The molar conductivity data of 1-butyl-3-methylimidazolium salicylate, [BMIm][Sal] as an active pharmaceutical ingredient ionic liquid (API-IL) have been determined in water and aqueous solutions of amino acids, glycine and L-alanine at T= (288.15 to 318.15) K. The molar conductivity data were analyzed by low concentration Chemical Model (lcCM) and limiting molar conductivities ), ion association constants ( K _A and standard Gibbs energies (∆ G _A ^° ) of the ion association process were calculated. The obtained values of and decrease with increase in the amino acid concentration. Moreover, the values of increase from glycine to L-alanine solutions due to the stronger solvation of the ions of [BMIm][Sal] by (COO− /NH3+) zwitterionic centers of glycine relative to L-alanine but this trend is vice versa for . The more negative values of (∆ G _A ^° ) for [BMIm][Sal] in glycine relative to L-alanine solutions is indicative of the more spontaneously and feasibility of the association process in this amino acid.