Synthesis and catalytic behavior of FCC catalysts obtained from kaolin by the in-situ method

In-situ zeolites NaY and Na[B]Y were synthesized on microspherical matrices of kaolin to obtain FCC catalysts. An alkaline pretreatment of the matrix was investigated in order to evaluate its effect on matrix properties and crystallization of the in-situ synthetized zeolites. Catalysts were characterized by SEM, TEM, Ar adsorption, XRD and NH3-TPD. It was observed an increase in the surface area and mesoporosity of the alkaline treated catalysts either synthetized with the presence of boron or with no boron in the hydrothermal reaction mixture. Ammonia TPD analyses have shown an increase in the amount and strength of the acidity of the catalysis with the zeolites crystallized on the pretreated matrices and exchanged with lanthanum ions. Thus, a combination between higher concentration of stronger acid sites and higher proportion of mesoporous generated in the matrices treated with alkaline solution had resulted in more active catalyst as shown by the triisopropylbenzene cracking experiments conducted here.

Graphical abstract

Recent advances of pore system construction in zeolite-catalyzed chemical industry processes

The kaleidoscopic applications of zeolite catalysts (zeo-catalysts) in petrochemical processes has been considered as one of the major accomplishments in recent decades. About twenty types of zeolite have been industrially applied so far, and their versatile porous architectures have contributed their most essential features to affect the catalytic efficiency. This review depicts the evolution of pore models in zeolite catalysts accompanied by the increase in industrial and environmental demands. The indispensable roles of modulating pore models are outlined for zeo-catalysts for the enhancement of their catalytic performances in various industrial processes. The zeolites and related industrial processes discussed range from the uni-modal micropore system of zeolite Y (12-ring micropore, 12-R) in fluid catalytic cracking (FCC), zeolite ZSM-5 (10-R) in xylene isomerization and SAPO-34 (8-R) in olefin production to the multi-modal micropore system of MCM-22 (10-R and 12-R pocket) in aromatic alkylation and the hierarchical pores in FCC and catalytic cracking of C4 olefins. The rational construction of pore models, especially hierarchical features, is highlighted with a careful classification from an industrial perspective accompanied by a detailed analysis of the theoretical mechanisms.