DETERMINATION OF EQUILIBRIUM CONSTANTS OF (5,6-DIOXO-3- ULFOQUINOLINE-7-YLOXY) ACETIC ACID IN AQUEOUS SOLUTION USING THE ITERATIVE APPROXIMATION ALGORITHM

Abstract

In this research, an iteration approximation algorithm based on the data of potentiometric titration and
the least squares method to determine equilibrium constants of (5,6-dioxo-3-sulfoquinoline-7-
yloxyl)acetic acid in aqueous solution is described. The ionic strength of all solutions were maintained
by 1.0 M of KCl solution. The value of equilibrium constants of (5,6-dioxo-3-sulfoquinoline-7-
yloxyl)acetic acid, which have been calculated by this method, are pKa1 = 1.841 was assigned for
ammonium group (of quinoline ring) and the pKa2 = 3.391 for carboxyl group. The programme has
been written with the Matlab language.
Keywords: (5,6-dioxo-3-sulfoquinoline-7-yloxyl)acetic acid; equilibrium constant; iteration
approximation algorithm.