THE USE OF PH-SENSITIVE NITROXIDE SPIN-PROBE TO STUDY DIFFUSION OF ACIDS DIFFUSION OF HCL AND CCL3COOH IN GLASSY GLYCEROL WATER MIXTURE/

Proton transfer from surrounding matrix to imidazolidine-based nitroxi de spin probe in viscous solution is shown to affect noticeably the ni troxide solid-like EPR spectrum. The use of this property is suggested for studying diffusion of guest acid molecules. Diffusion of hydrochl oric and trichloroacetic acid in glassy 85%/15% wt:wt glycerol/water m ixture has been studied. Values of diffusion coefficient obtained in t hr range 3.10(-9)-5.10(-8) cm(-2)/s show a remarkable breakdown of the Stokes-Einstein law. The data may be fitted by the empirical law D pr oportional to eta(-b), with b approximate to 0.6.