TRANSIENT RESPONSE ANALYSIS IN THE DETERMINATION OF ADSORPTION RATE COEFFICIENTS FOR PROPYLENE AND NITRIC OXIDE ON NiO/Al203 AEROGEL CATALYSTS

Abstract

Nickel oxide on alumina aerogel catalysts are known to be active and selective for the formation of acrylonitrile from nitric oxide and propylene. During an effort to investigate the mechanism of this reaction some transient feed experiments were carried out. The results obtained from these transient experiments were used to calculate the adsorption coefficients of propylene and nitric oxide on a NiO/Al2O3 aerogel catalysts with 1:1 Ni to Al atomic ratio. Adsorption coefficients of nitric oxide and propylene was determined by independently flowing the respective gases over the catalyst in a stream of helium at 410° C. Adsorption coefficient of nitric oxide on the catalyst at an oxidized state has been found to be less than that of propylene. When the two reactant gases flowed across the catalyst together the rate of adsorption of nitric oxide increased as the catalyst was reduced by propylene adsorption. The increased rate of adsorption of nitric oxide does not, however, influence the overall rate of formation of acrylonitrile.