Spectrophotometric determination of pK(a) values for some benzoic acid compounds in acetonitrile-water mixtures
ASIAN JOURNAL OF CHEMISTRY, vol.18, no.3, pp.2168-2178, 2006 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 18 Issue: 3
- Publication Date: 2006
- Journal Name: ASIAN JOURNAL OF CHEMISTRY
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.2168-2178
- Süleyman Demirel University Affiliated: Yes
Abstract
The dissociation pK(a) values of benzoic acid and substituted benzoic acids have been determined in water and acetonitrile-water mixtures (10%, 20%, 30%) by spectrophotometric measurements. The results obtained show that the solvents affect the acid equilibrium. Acetonitrile acts as a strongly differentiating solvent with a modest solvating power for many polar ionic solutes. Linear relationships between pK(a) values in acetonitrile-water mixtures and pK(a) values in pure water have been established for fourteen benzoic acids. rhe pHab is a computer program using the calculation dissociation constants from spectrophotometric data obtained from solutions at known pH.