PREPARATION OF ALUMINUM-RICH BETA-ZEOLITE

Beta zeolite, containing 10.3 Al atoms per tetragonal unit cell (Si/Al =5.2), has been synthesized. X-Ray diffraction (XRD), thermogravimetri c analysis (TGA) and chemical analysis were used to characterize the s amples. The TGA study indicated that Beta zeolites at Si/Al<7.5 contai n only one type of tetraethylammonium (TEA) species and at Si/Al>7.5 t wo types of TEA species. Al-27 and Si-29 magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra confirmed that in as-synthesized Beta all Al atoms are present in the zeolite framework positions. The Fourier transform infrared (FTIR) spectra of chemisorbed pyridine were used to investigate the acidic properties of the aluminum-rich Beta z eolite.