Spectroscopic and Potentiometric Study of 2,3-Dihydroxybenzoic Acid and its Complexation with La(III) Ion

Suban K. Sahoo, Rati Kanta Bera, Minati Baral and B. K. Kanungo

Department of Chemistry, Sant Longowal Institute of Engineering & Technology, Longowal- 148106, India.
* Corresponding author: E-mail: suban_sahoo@rediffmail.com

Abstract
The equilibrium reactions between 2,3-dihydroxybenzoic acid (2,3-DHBA) and Lanthanum(III) ion was investigated in an aqueous medium of 0.1M ionic strength and 251 C by potentiometric and spectrophotometric methods. Formation of complexes of the types ML andML2H were observed and their stability constants were reported. The ligand showed competitive coordination mode in solution: in acidic medium, 2,3-DHBA showed preference to salicyclate type whereas catecholate type in basic media.

Keywords: Dihydroxybenzoic acid, lanthanum and stability constants.