MOLAR VOLUME EFFECT OF PYRIDYLAZOPHENOLS AND THEIR METAL-CHELATES ON THEIR DISTRIBUTION BETWEEN AQUEOUS MICELLAR PSEUDOPHASES IN TRITON X-100 MICELLAR SOLUTIONS

The distribution constants of 2-(2-pyridylazo)phenol (PAP), 2-(2-pyrid ylazo)-5-methylphenol (PAP-5Me), and metal chelates with PAP and PAP-5 Me between aqueous micellar psuedophases were evaluated in aqueous mic ellar solutions of Triton X-100. The distribution constants were found by measurement of equilibrium shifts in acid-base and complexation re actions in the presence of micelles at an ionic strength of 0.1 ((Na+, H+) ClO4-) and at 293+/-1 K. The metal chelates (vanadium(V), nickel( II), and iron(II)) had a linear correlation between their logarithmic distribution constants and their van der Waals volumes. PAP and PAP-5M e had a different kind of correlation from the metal chelates did. The se results were explained by the difference in the part of the micelle s into which hydrophobic chelates and hydrophilic chelating reagents w ere incorporated.