Adsorption of gases,vapors and liquids in zeolites at high pressures

The linearity of adsorption isotherms, which is well preserved independently of the state of aggregation of the equilibrium phase, the absence of discontinuities on adsorption isotherms on passing into the region of the liquid state, and the considerable differences in the behavior of the temperature dependence of the densities of the adsorbate and of the substance adsorbed along the saturation line; all these facts indicate that the adsorbate in the micropores of zeolites is in a special state of aggregation. The linearity of the isosteres and the maxima on the curves for the specific heat of the adsorbate at constant pressure when its concentration in the cavities is high probably indicate the presence of phase transitions of the second kind of the adsorbed substance.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 507–511, March, 1990.