Abstract:

Methanol-to-olefin（MTO） reaction provides a new approach to produce light olefins via the non-petroleum route. The development of novel catalysts is the key to improve the performance of MTO reactions. In this work， the synthetic conditions and thermal stability of EAB zeolites with eight-membered rings were systematically investigated. The topological structure， crystal morphology， skeleton composition and acidity of the obtained EAB zeolites were characterized by X ray diffraction， scanning electron microscopy， inductively coupled plasma optical emission spectrometry， and ammonia-temperature programed desorption measurements. The structure of the EAB zeolite remained unchanged after calcination in air even at 550 ℃ when the K⁺ and Cs⁺ ions were introduced into EAB zeolite pores. Significantly， the crystallization rate can be accelerated and the impure crystalline phase can be suppressed by adding seeds to the synthesis system. The complete crystallization time can be shortened to 3 d. In addition， the EAB zeolite was used for the first time in the MTO catalytic reaction， and showed a high selectivity of ethylene， propylene and butene up to 87.2%. and a high selectivity ratio of propylene to ethylene up to 2.4. This work provides a reference for the development of new catalysts with adjustable selectivity of propylene and ethylene for MTO reactions.

Key words: EAB zeolite, Thermal stability, Hydrothermal synthesis, Methanol-to-olefin, Light olefin