02-P-35 - Synthesis of pure silica Beta by the conventional hydrothermal method

Abstract

Publisher Summary This chapter describes the synthesis of pure silica Beta by the conventional hydrothermal method. Pure silica Beta has been crystallized from alkali-free hydrogel containing tetraethylammonium hydroxide and fumed silica at 413 K by the conventional hydrothermal synthesis method. Characterization has been done by X-ray diffraction (XRD), infrared (IR), solid-state nuclear magnetic resonance (NMR), and thermal analysis. The results show that a highly crystalline pure silica Beta is formed. 29 Si magic angle spinning (MAS) NMR reveals that the pure silica Beta has a small number of Q 3 sites originating from structural defects and almost half of Q 3 sites are silanol groups. Thermal analysis shows that pure silica Beta possesses nonequivalent Q 3 sites that are siloxy groups counterbalanced by TEA + cations.