Ultrasonic and Microwave Pretreatment for Hydrothermal Synthesis of Nanosized SAPO-34s and their Catalytic Performance in MTO Reaction

In order to enhance the catalytic performance of sapo-34 catalyst for the reaction of methanol to olefins (mto), ultrasonic and microwave-assisted aging method was employed in static hydrothermal method to synthesize nano-sized sapo-34. the effects of the application of this method on the chemical composition, morphology, surface area and total acidity of sapo-34 were investigated by xrd, fe-sem, nitrogen adsorption–desorption and nh3-tpd techniques. the catalytic performance of synthesized sapo-34 was investigated for mto reaction in a fixed-bed reactor under the same operating conditions (t = 450 °c, p = 1 atm, and whsv = 4 h^-1). comparing with the sapo-34 synthesized with conventional hydrothermal method, the sample synthesized with simultaneous use of us and mw-assisted aging methods possessed larger surface area and small crystal size and exhibited higher selectivity to light olefins (c^= 2 - c^= 4) and longer lifetime.