Preparation and catalytic performance of fully crystalline MCM-22 zeolite catalyst
Fully crystalline MCM-22 zeolite catalyst was efficiently synthesized by hydrothermal crystallization method.The crystal structure,micro morphology,and acid property of the as-prepared catalyst were characterized by X-ray diffraction,scanning/transmission electron microscopy(SEM and TEM),NH3-TPD,and so on.The catalytic performance of the as-prepared catalyst in the liquid-phase alkylation of benzene and ethylene to ethylbenzene was investigated.The results showed that the relative crystallinity of MCM-22 zeolite with ultra-thin layered structure reached 100%after 40h crystallization at 160℃.In addition,the morphology of the catalyst after crystallization remained in strip shape with 100%active component,and the mechanical strength of the catalyst was as high as 82N/cm,which fully met the requirement of industrial application.Under reaction conditions close to industrial process:temperature of 180℃,pressure of 3.5MPa,ethylene weight hourly space velocity(WHSV)of 1h-1,molar ratio of benzene to ethylene of 2.5,the as-prepared fully crystallized MCM-22 zeolite catalyst showed good catalytic activity,selectivity,and stability.The ethylene conversion and the ethyl selectivity of the catalyst were close to 100%and 99.84%,respectively,and the content of heavy components remained about 1000μL/L within 1000h.
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