The high selectivity of Ce-hierarchical SAPO-34 nanocatalyst for the methanol to propylene conversion process

Abstract

Cerium-hierarchical SAPO-34 zeolite, synthesized hydrothermally in the presence of n-propyl amine as a mesoscale template and pore size modifier, is used for the methanol to propylene (MTP) conversion. A high selectivity for propylene (52.5%) compared to a conventional microporous SAPO-34 catalyst (28.7%) in a fixed-bed reactor under atmospheric pressure at 450 °C and WHSV of 1.0 h−1 is achieved. High conversion of methanol to propylene, longer catalytic lifetime (7 h) and improved selectivity for propylene to ethylene (P/E = 5.1) are observed. These are attributed to the presence of hierarchical porosity, decrease of the acidic character of catalytic sites due to the presence of Ce and smaller path for the diffusion distance inside the mesopores having different acidity strength. The synthesized catalysts are characterized by XRD, FE-SEM, BET, NH3-TPD and TGA techniques.