Microwave-Assisted Hydrothermal Synthesis of CHA Zeolite for Methanol-to-Olefins Reaction

A cost-effective aluminum CHA zeolite was synthesized by seed-assisted hydrothermal synthesis under microwave radiation to shorten the crystallization time to 6 h. The CHA was synthesized under different stirring rates and evaluated in methanol-to-olefins reaction at three different temperatures by using a fixed-bed reactor. Boron was incorporated by in situ synthesis also under microwave radiation. The X-ray diffraction pattern revealed that the synthesized CHA was crystalline and in well agreement with the reference CHA. The reaction evaluation revealed that the reaction temperature affected both the catalyst stability and selectivity to light olefins. At a lower temperature, the synthesized CHA was more stable and less selective to olefins, while at a higher temperature, the catalyst was less stable and more selective to olefins. The incorporation of boron only enhanced the selectivity to ethylene and propylene at the start of the reaction.