POTENTIOMETRIC DETERMINATIONS OF DISSOCIATION CONSTANTS AND THERMODYNAMIC PARAMETERS OF 4-AMINOQUINOLINE IN AQUEOUS, AQUEOus-DIOXANE, AQUEOUS ETOH ANDAQUEOUs-MEOH SOLUTIONS AT VARIOUS TEMPERATURES

Authors

  • Hafiz A Bari Indhar National Centre of Excellence in Analytical Chemistry, University of Sindh, Allama I I Kazi Campus, Jamshoro, Sindh, Pakistan
  • A W K Khanzada National Centre of Excellence in Analytical Chemistry, University of Sindh, Allama I I Kazi Campus, Jamshoro, Sindh, Pakistan

Keywords:

Dissociation constants, Thermodynamic ionization constant, 4-Aminoquinoline

Abstract

The dissociation constant (pK) and thermodynamic parameters Gibb's free energies of 4-aminoquinoline are measured by
potentiometric pH titrations in aqueous solution at 25 to 50°C and in three mixed aqua-organic media (dioxane, EtOH and
MeOH) at 25°C ± O.loC. It is observed that pKaM and pKaT(concentration ionization and thermodynamic ionization
constants) values of 4-aminoquinoline decrease with the increase in temperature and concentration of organic-water solvent
systems. The curve is a parabolic one. It is noted that the pKaMand pKaTvalues of this compound are higher than that
quinoline and some of its amino derivatives. These results are discussed in terms of solvent characteristics, solvent basicity
and stabilization of conjugate acid for base by hydrogen bonding interaction in hydro-organic solvent media. The values of
dissociation constant are calculated by a computer program written in GW-BASIC. From p K. values Gibb's free energies
are computed and discussed interms of solute solvent interactions.

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Published

2001-08-20

How to Cite

Bari, H. A., & Khanzada, A. W. K. (2001). POTENTIOMETRIC DETERMINATIONS OF DISSOCIATION CONSTANTS AND THERMODYNAMIC PARAMETERS OF 4-AMINOQUINOLINE IN AQUEOUS, AQUEOus-DIOXANE, AQUEOUS ETOH ANDAQUEOUs-MEOH SOLUTIONS AT VARIOUS TEMPERATURES. Biological Sciences - PJSIR, 44(4), 208–214. Retrieved from https://v2.pjsir.org/index.php/biological-sciences/article/view/1926

Issue

Vol. 44 No. 4 (2001): Pakistan Journal of Scientific and Industrial Research

Section

Articles