Potentiometric studies of complex equlibria of CaII MgII and ZnII with 5-sulphosalicylic acid in cationic micelles of CTAB

摘要

Formation of metal ligand complex species of 5-sulphosalicylic acid with Ca^II, Mg^II and Zn^II metal ions have been studied potentiometrically in various composition (0.0, 0.5, 1.0. 1.5, 2.0, and 2.5% w/v) of cetyltrimethylammonium bromide (CTAB). The study has been carried out at 303 K temperature and maintaining 0.16 mol dm⁻³ ionic strength using NaCl. The dynamic species belongs to 5-sulphosalicylic acid are LH2^- and LH^2-. The best fit of complex speciation has been preferred on basis of statistical parameters like skewness, χ², Kurtosis and crystallographic R-factor. ML2H, ML2H2 and ML3H3 type complex were formed by the complexation of 5-sulphosalicylic acid with the metal ions. The change in stability of complex species with composition of the surfactant has been illustrated on the basis electrostatic grounds. Distribution of chemical species with respect to pH and various compositions medium and probable complex equilibria are also studied.