Titanium carboxylate complexes stability constants estimated by four graphical methods

摘要

This investigation represents a comparative study of four graphical methods for overall stability constant estimation techniques, included point wise calculation method, half integral method, linear plot method and least squares method, in purpose to select the most sensitive and accurate method, the paper aiming also to determine the parameters that affect the precision of these methods under investigation. Metal-ligand stability constant and stoichiometries of above systems are to be determined by Calvin and Bjerrum pH-metric titration technique as adopted by Irving and Rossotti. For this purpose titanium has been chosen as a central metal ion. Titanium element from first transition series of d-block and has four valence bond electrons 3d24s2. Acetic acid, oxalic acid and oxalacetic acid have been selected as ligands. The obtained results seem in a good agreement with each other, with some restriction on least squares method for accumulation of error in Kn-1. These suggestions have been introduced in conclusion for treatment of data by least squares method and Henderson's Hasselbalch's equation and other modifications have been done.