Determination of pK(a) values of azlactone dyes in non-aqueous media

ERTEKİN K., ALP S., Yalcin I.

DYES AND PIGMENTS, vol.65, no.1, pp.33-38, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 65 Issue: 1
  • Publication Date: 2005
  • Doi Number: 10.1016/j.dyepig.2004.06.011
  • Journal Name: DYES AND PIGMENTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.33-38
  • Keywords: azlactone, non-aqueous media titrations, potentiometric method, NON-AQUEOUS MEDIA, GLACIAL ACETIC-ACID, REDOXIMETRIC TITRATIONS, MANGANESE(III) ACETATE, NITROBENZENE SOLVENT, BASICITY, DERIVATIVES
  • Dokuz Eylül University Affiliated: Yes

Abstract

4-AryIidene-2-aryl-5-oxazolone (azlactone) structures have wide range of applications arising from their promising photophysical and photochemical activities. Some of this class of dyes exhibit pH-dependent absorption and emission based response. For this reason, precise determination of the acidity constants (pK(a)) of the azlactone derivatives is necessary for further studies in different media. In this study. five different aziactone derivatives were chosen to obtain pK(a) values. The acidity constants were determined by using potentiometric titration method. The chosen derivatives were titrated with tetrabutylammonium hydroxide in solvents of dimethylformamide. tert-butanol, isopropanol, acetone and acetonitrile. A computerizable derivative method was used for a precise description of the end point and consequently the pK(a) values. All compounds exhibited stoichiometric and well shaped potentiometric titration curves. (C) 2004 Elsevier Ltd. All rights reserved.