Studies on structure-directing role of THF in synthesis of high silica zeolites

Four types of zeolites in the system of tetrahydrofuran(THF) - Na2O - SiO2 - Al2O3 - H2O were synthesized under different hydrothermal conditions. With increase of the ratios of SiO2/Al2O3 in the reactant, the zeolites synthesized were in the following order: mordenite (MOR), ZSM - 35, ZSM - 5, ZSM - 39. The template molecules of THF trapped in the channels or the cages of these zeolites were characterized by C-13 CPMAS NMR spectra, TG/DTG/DTA and EDX composition analysis. The facts that the apparent shift of delta (C(1)) and delta (C(2)) of THF and the higher temperatures for THF escaping from the zeolites synthesized confirm that THF strongly interacts with the framework of the zeolites, playing a role of the template.