Butadiene formation reaction from ethanol over various kinds of silica-magnesia having different MgO contents were studied from the standpoint of its acid-base catalysis. Maximum acidity was obtained at 50% MgO, while basicity increased with the MgO content. Silica-magnesia (85% MgO) having adequate acidity and basicity gave the maximum activity. The reaction mechanism and the roles of acidic and basic sites are discussed. The rate controlling step is the acetaldehyde formation catalyzed by basic sites.

No abstract

No abstract

No abstract

Decomposition of Freon-12 (CCl2F2) and methyl chloride (CH3Cl) over gold catalysts were studied. Au/Co3O4 showed a high activity for CH3Cl but a lesser activity for CCl2F2 while Au/Al2O3 showed moderate activities for the both reactants. The first step of the reactions over Au/Al2O3 was considered as substitution of Cl by surface OH group on support surface.