Preparation and characterization of zeolite-containing silica-aluminas with three layered micro-meso-meso-structure and their reactivity for catalytic cracking of soybean oil using Curie point pyrolyzer

Abstract

Since fats are quite large molecules, catalysts with layered structure are necessary in order to decompose them efficiently. In this work, zeolite containing silica-aluminas with three layered micro-, meso- and meso-structure were prepared from zeolite-containing silica-aluminas with two layered micro-meso-structure and silica with very large mesopores prepared by the gel skeletal reinforcement. The derived substances showed hysteresis curves at two points in N2 isothermal adsorption and desorption experiments, indicating containing two kinds of mesopores. Actually, there were sharp peak of small pore size and broad peak of large mesopore size in BJH plots. The former corresponded to two-layered catalysts, and the latter was assigned to the silica with reinforced framework.The evaluation of the catalytic cracking of soybean oil using the obtained layered catalysts was performed by Curie point pyrolyzer as the new and convenient technique. Three-layered catalysts containing more than 25wt% zeolite showed higher conversion than two-layered catalysts containing 50wt% zeolites. The activity of three-layered catalyst containing 18wt% zeolites, which was obtained from two-layered catalyst originally containing 25wt% zeolite, was similar to that of the original two-layered catalyst. It implies that the large size of pores and the proper distribution of acid sites are necessary to convert fats with large molecules efficiently.