Adsorption data are presented for benzene on four silica powders whose surface hydration has been studied previously by infra-red and other methods.1 The adsorption isotherms were obtained down to low pressures, and integral entropies of adsorption calculated with the aid of a Mercury computer. The low-pressure sections of some of the isotherms indicate the presence of surface micropores. The entropies are interpreted in terms of models of the adsorbed layers, and indicate strong localization of benzene at low coverages even for fully dehydrated silica. For partially or fully dehydrated powders, the benzene surface film entropy approaches that of liquid benzene at coverages above about 0.3 of a monolayer. Localization of the benzene at low coverages decreases on decreasing surface hydration and on annealing the silica surface.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry