Synthesis, characterization and catalytic properties of SAPO-34 synthesized using diethylamine as a template

SAPO-34 molecular sieve was successfully synthesized using diethylamine (DEA) as a template. The influence of template concentration and silica concentration on the synthesis were investigated. Pure SAPO-34 could be obtained when n(DEA)/n(Al₂O₃)  1.5 and n(SiO₂)/n(Al₂O₃) > 0.1 in the synthesis gel. Further increase of DEA concentration in the starting gel n(DEA)/n(Al₂O₃) > 3] has a negative effect on both crystallinity and crystal yield. The products were characterized by XRD, XRF, SEM, NMR, FT-IR, TG-DTA and nitrogen adsorption techniques. It was found that SAPO-34 synthesized with DEA as a template has the characteristic of high silicon incorporation and exhibits good thermal and hydrothermal stability. The catalytic performance of SAPO-34 was tested by methanol-to-olefin (MTO) reaction and high olefins (C₂H₄ + C₃H₆) selectivity was obtained.