Nitrogen containing SAPO-34 molecular sieves were prepared by a secondary technique with a starting material of SAPO-34 treatment at elevated temperature by ammonia in this study. Comparing with precursor, the obtained samples still kept high crystallinity and high specific surface area after treated at high temperature for different times detected by XRD and BET measurements. The catalytic performance of nitridized samples for MTO(methanol make olefins) was investigated. It was found that olefins selectivity was increased on the SAPO-34 molecular sieve treated by ammonia, ethylene selectivity increased from 11.6% to 39.7%. Nitridation changed the acidity of SAPO-34 molecular sieve, which responsible for light olefins.
The hydrothermal crystallization of THF-FER zeolite was investigated in the reactant system of Na2O-SiO2-Al2O3-H2O with tetrahydrofuran （THF） as the template in the presence of various catalytic amount of glycerol [CH2（OH）CH（OH）CH2（OH）, Glyc] in the temperature range of 413--473 K. Powder X-ray diffraction （XRD） was used to observe the crystallization process, and scanning electron microscope （SEM）, ^13C cross polarization （CP） and ^27Al magic angle spinning nuclear magnetic resonance （MAS NMR）, X-ray fluorescence scattering spectroscopy （XRF）, thermal analysis and nitrogen sorption were used to characterize the zeolite synthesized in the reactant system with Glyc. The catalytic amount of Glyc could promote the crystallization of FER zeolite, to result in lowering the reaction temperature, shortening the period of the zeolite crystallization and effectively restraining cocrystallization of MOR zeolite as an impure phase especially at low reaction temperature, and possess a significant effect on the morphology and the crystal size of TI-IF-FER zeolite.
