Methanol conversion to light olefins over surfactant-modified nanosized SAPO-34

Abstract

Ultrasonic and microwave-assisted aging processes were employed in the static hydrothermal synthesis of nanosized SAPO-34 molecular sieve. A series of nanosized hierarchical SAPO-34 samples with different degrees of mesoporosity were utilized to investigate the impacts of mesoporosity on the catalytic performance of the methanol to olefins (MTO) reaction. The so-called series were synthesized in the presence of various mesogenous templates, such as TPOAC, CTAB, and their combinations. These SAPO-34 samples were characterized by XRD, FE-SEM, BET, FT-IR and NH3-TPD techniques. The catalytic activities were studied in a fixed-bed reactor under atmospheric pressure, 450 °C and WHSV of 4 h−1. Comprehending the results, it can be said that in comparison with the typical catalysts, reliable MTO catalytic lifetime (420 min) as well as sufficiently high light olefins selectivity (90 %) was obtained through the nanosized hierarchical porous SAPO-34 templated with a mixture of 50 % CTAB and 50 % TPOAC. This achievement is associated to its effective combination of acidity and porosity.