Investigation into state of tungsten(6) in solutions of tartaric acid and malic acid by the comparative dialysis method

A study was made of the state of tungsten complexes in aqueous solutions of tartaric and malic acids. The investigation was conducted by the method of comparative dialysis, the reference ion being Co2, according to the orthogonal plan of the 2nd order for four factors: the pH value (2 (<=) pH (<=) K), the tungsten concentration (2.8 (<=) -lg[W] (<=) 3.6), the molar oxyacid-to-tungsten ratio (2 (<=) [OK]/[W] (<=) 15) and the temperature of the solution (5 (<=) t deg). In the case of tartaric acid the qreatest value of all pH values was K=8. In the case of malic acid K=6. The dependence of the dialysis coefficient on the above factors was approximated using a corresponding model by the regression analysis of experimental data. With increase in temperature and pH the excess in tartaric acid with respect to the stoichiometry plays the part of the depolymerizer of macromolecules. The stability of the malate complex is sufficiently hiqh to prevent the hydrolytic polymerization