SYNTHESIS OF MORDENITE SINGLE-CRYSTALS USING 2 SILICA SOURCES

Starting with the batch composition 1 Al2O3 : 85 SiO2 : 19 Na2O: 575 H 2O, a study was made to determine the effect of various additives and other modifications of the starting composition on the growth of large r mordenite crystals in this system. It was found that synthesis of la rger mordenite single crystals requires the use of two silica sources, the addition of an appropriate salt, and higher basicity. Thermogravi metric analysis showed two ranges of weight loss which might be concer ned with diffusional restrictions because of the large dimensions of m ordenite crystals. MAS n.m.r. indicated that the as-synthesized morden ite should be small port mordenite, and there is no octahedral aluminu m in the framework of the products. Results of the disproportionation of beta-methylnaphthalene over different sizes of mordenite crystals s how that the shape selectivity observed in these reactions might be re lated to diffusional restrictions inside the channels of mordenite.