ABSTRACT

Mordenite is an industrially important zeolite used as a catalyst  for various  reactions,  viz. hydrocarbon hydrocracking, hydroisomerization, alkylation, reforming, and dewaxing, as well as in the production of dimethyl amines. It has, recently, been used for hosting semiconductors, chemical sensors and non-linear optical materials. There have been numerous articles and patents concerning mordenite synthesis in the presence or absence of organic templates as structure directing agents that help tailoring pore openings for some selected catalytic reactions. Nano-particle (≤100 nm), large-crystal (7-500 micron) types of mordenite have been synthesized by conditioning the gel composition, crystallization and templating. Synthesis of such nano-particle mordenites permits applications to sorption and catalysis with developed surface properties as compared to the micro-particle ones. Mordenite’s shape selectivity, acidity and thermal stability are unique features. It decomposes at 1113 K yielding amorphous anorthite and SiO₂ materials. In order to optimize the catalytic properties of mordenite, the zeolite has been subjected to chemical modification using (i) metal ion incorporation, (ii) pore size engineering, and (iii) partial dealumination. The present article reviews and assesses impacts of these various modification methods on characteristics, adsorptive and catalytic conduct of mordenite zeolite toward a number of reactions of industrial and technological importanace, e.g. organic synthesis, hydrocarbon disproportionation and isomerization, NO_x selective reduction, total oxidation, and cracking reactions.