Influence of Pore Structure on the Catalytic Behavior of Clay Compounds

Abstract

The effect of pore structure on the catalytic activity of pillared clays was investigated using alumina-pillared montmorillonite (Al-mont) with a microporous structure and alumina-pillared saponite (Al-sapo) having mesopores. The disproportionation and isomerization of trimethylbenzene, and the cracking of cumene were adopted as model reactions. The catalytic activity of pillared clays was affected by pore structure as well as by acidity: Al-mont having less acidity was more active for the disproportionation reaction than Al-sapo, although the effect of pore structure on the cracking and isomerization was small compared with the disproportionation. The microporosity is considered to enhance the concentration of reactant molecules at the acid sites, resulting in a high catalytic activity. It is suggested that the significant influence of pore structure on disproportionation is attributed to the second order kinetics of disproportionation which is a bimolecular reaction.