SYNTHESIS OF SODALITE IN NONAQUEOUS SOLVENTS

In an attempt to prepare zeolites of a new type or those having new su rface properties, their synthesis in a nonaqueous solvent system using methanol, 2-propanol, ethylene glycol or monoethanolamine was studied . Sodalite of high crystallinity was obtained using monoethanolamine a s solvent, and tetraethoxysilane, aluminum triisopropoxide, and sodium hydroxide as raw materials. The synthesis conditions were SiO2/Al2O3 = 2, Na2O/SiO2 = 5, solvent/Na2O = 90 molar ratio at 150 degrees C, an d 22-490h of aging time. The properties of these crystals were compare d with those obtained from 2-propanol containing water (1.2 vol% of so lvent) and from pure water. Our crystals had a slightly larger lattice constant and adsorbed a large amount of N-2 gas; in particular, the s hape of the adsorption isotherm was unique compared with those of othe rs, This greater adsorption may be attributed to adsorption at the inn er surface, that is, the windows of sodalite allow the penetration of N-2 into the pore structure. This was also suggested by the larger lat tice constant.