丙烯在ZSM-5沸石上齐聚反应的研究 Ⅰ. 模板剂用量对丙烯齐聚反应的影响

丙烯在ZSM-5沸石上齐聚反应的研究 Ⅰ. 模板剂用量对丙烯齐聚反应的影响

  • 摘要: 考察了不同正丁胺(NBA)模板剂用量合成ZSM-5沸石的物化特性和催化性能。采用XRD、SEM、NH3-TPD和BET等手段对合成样品的物化特性进行了表征。结果表明,模板剂与SiO2摩尔比在0.67~0.22时合成的ZSM-5沸石结晶度高于90%;随着模板剂用量的减少,ZSM-5沸石的平均粒径减小,强酸量也存在相同的趋势。丙烯齐聚反应评价结果显示,模板剂用量对合成ZSM-5沸石的催化活性有显著影响,模板剂与SiO2摩尔比在0.67~0.45之间合成的沸石催化性能较好。

     

    Abstract: ZSM-5 zeolites synthesized with varying the concentration of n-butylamine in gel were studied. The samples were characterized by XRD, SEM and BET surface area measurements. Under synthetic condition of this study, the range of optimum concentration of n-NBA(NBA/SiO2) is from 0.67 to 0.22, the relative crystallinity of ZSM-5 zeolites synthesized is over 90%. As template concentration decreased, particle size and BET surface area of ZSM-5 zeolites decreased. The acidity was measured by temperature-programmed desorption (TPD) of ammonia. It was found that the number of strong acid sites decreased almost linearly with the concentration of template. Propene oligomerization reaction was carried out over the samples to evaluate the catalytic properties of ZSM-5 zeolites. The template concentration affected significantly on catalytic activities of the ZSM-5 zeolites. ZSM-5 zeolites synthesized with varying the concentration of n-butylamine form 0.67 to 0.22 in gel showed better catalytic activities and stability.

     

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