THE SURFACE CHARACTERISTICS REQUIRED FOR ISOSYNTHESIS OVER ZIRCONIUM DIOXIDE AND MODIFIED ZIRCONIUM DIOXIDE

The surface requirements for the two isosynthesis chain growth reactions, condensation and CO insertion, over zirconium dioxide were studied by modifying zirconium dioxide in controlled ways and studying the effects of these changes on the isosynthesis reaction products at 425°C and 35 atm. The oxygen vacancy availability was altered by the addition of dopants Y2O3 and CaO at various levels. The acid/base strength of the catalysts was altered by additives including H2SO4, Sc2O3, Y2O3, and Sm2O3. Calcination methods and temperatures for ZrO2 were varied. Lewis acid sites and oxygen vacancies were found to enhance the condensation reaction. The CO insertion reaction was enhanced by basic sites which were activated by high-temperature treatment. The selectivity of the isosynthesis reaction is caused by a balance between the strength and quantity of acid and base sites on zirconium dioxide. © 1990.