SURFACE-PROPERTIES OF ZIRCONIUM-OXIDE AND ITS CATALYTIC ACTIVITY FOR ISOMERIZATION OF 1-BUTENE

Acidic, basic, oxidizing, and reducing properties of ZrO2 were measured by the ir spectra of adsorbed pyridine, by CO2 adsorption or the ESR of diphenylnitroxide radical formed from diphenylamine and O2, by the ESR of adsorbed triphenylamine, and by the ESR of adsorbed nitrobenzene, respectively. The variations of these properties with pretreatment temperature of ZrO2 were independent of each other. The maximum concentrations of these sites and the pretreatment temperatures at which the maxima were obtained were 3.9 × 10-8 mole/m2 and 400 °C for acidic sites, 1.7 × 10-7 mole/m2 and 700 °C for basic sites measured by diphenylamine, 1.5 × 10 mole/m2 and 700 °C for oxidizing sites, and 4.3 × 10-8 mole/m2 and 500 °C for reducing sites. Among these properties, it was the basic property with which the activity for isomerization of 1-butene correlated best. The activity was poisoned not only by CO2 but also by NH3 or triethylamine, indicating that the active sites consist of both basic and acidic sites. The results of the coisomerization of 1-butene- d0 d8 showed that the reaction involved primarily an intramolecular hydrogen transfer. © 1979.