Evaluation of Protonation Constants of  L–Asparagine and Maleic Acid in Aqueous  and Aqueous Solutions of Ethylene Glycol

CHOPPA NAGESWARA RAO; MALLA RAMANAIAH; B.B.V.SAILAJA

Volume : III, Issue : III, March - 2014

Evaluation of Protonation Constants of L–Asparagine and Maleic Acid in Aqueous and Aqueous Solutions of Ethylene Glycol

Choppa Nageswara Rao, Malla Ramanaiah, B. B. V. Sailaja

Abstract :

The solute–solvent interactions of L–asparagine and maleic acid have been studied in 0–50% v/v ethylene glycol–water media using the pH–metric method. The protonation constants have been calculated with the computer program MINIQUAD75. Selection of the best fit chemical model of the acid–base equiliia is based on standard deviation in protonation constants and residual analysis using crystallographic R–factor and sum of squares of residuals in all mass balance equations. Linear variation of protonation constants with inverse of dielectric constant of the solvent mixture has been attributed to the dominance of the electrostatic forces. Distributions of species, protonation equiliia and effect of influential parameters on the protonation constant have also been presented.