3027.     SARTORI, G., AND FANO, U.  [Adsorption of Hydrogen, Carbon Dioxide, and Methanol on Zinc Oxide.]  Gazz. chim. ital., vol. 67, 1937, pp. 69-85; Chem. Zentralb., 1937, II, p. 944; Chem. Abs., vol. 31, 1937, p. 6077.

        Work is an extension, with an improved apparatus, of the experiments of Natta and Casazza (abs. 2386).  The adsorption isotherms of H₂, CO, CO₂, and MeOH on ZnO at 0°, 36°, 76°, 106°, and 120° were measured.  The ZnO was prepared by thermal dissociation of smithsonite.  Adsorption of H₂ and CO followed closely the Langmuir law, but that of CO₂ and MeOH showed deviations from this law, as a result of chemical sorption of CO₂ and capillary condensation of MeOH.  the periods of permanence of the adsorbed molecules were determined.  The periods for CO₂ and MeOH were much longer than for H₂ and CO, and this fact is shown to be related to the character of their adsorption isotherms.  The thermal coefficients were not linear functions; this indicates that the centers of adsorption activity at different temperatures have different potentials.  The calculated heats of adsorption agree with the experimental values of Taylor and Sickman (abs. 3342).  The heat of adsorption of MeOH equals the heat of condensation; this confirms the concept of capillary condensation.  The kinetics of adsorption of H₂ can be derived from the equation of Langmuir.  CO and CO₂ show deviations proportional to the square roots of their molecular weights, and related to the rates of diffusion in the pores of the catalyst.  The kinetics of adsorption of MeOH can be derived by dividing the phenomenon into 2 phases, an instantaneous phase and an exponential phase.