KINETICS OF DEHYDROGENATION OF ISOPROPYL ALCOHOL OVER A ZINC OXIDE CATALYST - CONSISTENCY WITH ADSORPTION FUNCTION OF ISOPROPYL ALCOHOL ON ZINC OXIDE

The rate of dehydrogenation of isopropyl alcohol over a zinc oxide catalyst has been measured at 158-195 °C, at an isopropyl alcohol pressure range of 0.03-100 torr. The rate measurements have been tested for consistency with a previously determined adsorption function of isopropyl alcohol on zinc oxide. The adsorption function assumes Langmuir adsorption on a heterogeneous surface with five sets of adsorbing sites. The corresponding kinetic equation could be well fitted to the experimental rates using a suitable set of rate constants and activation energies, but using the previously determined adsorption function directly. In the experimental range which covered a factor of more than 3000 in isopropyl alcohol pressure and a factor in reaction rates of 170 the mean deviation between observed and calculated rates was less than 6%. The results are therefore an indication that a previously proposed model, assuming that a heterogeneously catalyzed reaction may take place on more than one set of active centers on the catalyst, is correct. © 1969.