乙醇体系合成高硅铝比ZSM-5分子筛  

Synthesis of ZSM-5 Zeolite with High Si/Al Ratio in Ethanol System

作　　者：陶金泉 崔岩[1] 张淑莹 迟克彬[1] 周亚松[2] TAO Jinquan;CUI Yan;ZHANG Shuying;CHI Kebin;ZHOU Yasong(PetroChina Petrochemical Research Institute,Beijing 102206,China;China University of petroleum-Beijng,Beijing 102206,China)

机构地区：[1]中国石油天然气股份有限公司石油化工研究院,北京102206 [2]中国石油大学(北京),北京102206

出　　处：《硅酸盐学报》2021年第9期2009-2016,共8页Journal of The Chinese Ceramic Society

基　　金：中国石油天然气股份有限公司直属科研院所基金(2020-CB-05-05)。

摘　　要：在乙醇体系内合成高硅铝摩尔比[n(SiO_(2))/n(Al_(2)O_(3))>70]的ZSM-5分子筛,使用晶种辅助晶化,通过精确调整乙醇用量、晶化时间、碱硅比的条件合成出高硅铝比ZSM-5分子筛,采用X射线衍射谱、扫描电子显微镜等方式对其晶型、形貌、孔道结构进行了表征。结果表明:当硅铝比低于70,醇硅比为1.5时在单一的乙醇体系内可以直接合成出结晶度较高、分散度较好的ZSM-5分子筛,当硅铝比大于90时单一的乙醇体系中难以合成出高结晶度的ZSM-5分子筛。加入微量晶种可明显提高乙醇体系下可合成出ZSM-5分子筛的硅铝比范围至150,并且可以缩短晶化诱导期及总体晶化时间。加入晶种辅助晶化的产品ZSM-5分子筛形貌区别于单独以晶种或乙醇体系合成的ZSM-5分子筛,晶粒尺寸更加均一,且分散性更高。以晶种辅助晶化时最佳碱硅比随着硅铝比的提高有所下降,但仍需提供体系足够的碱性以溶解硅源以发生晶化反应。ZSM-5 zeolite with a high Si/Al ratio(n(SiO_(2))/n(Al_(2)O_(3))>70)was synthesized in ethanol system via seed-assisted crystallization.The crystal form,morphology and pore structure of ZSM-5 zeolite were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results show that ZSM-5 zeolite with high crystallinity and well-dispersion can be directly synthesized in a single ethanol system when Si/Al ratio is lower than 70 and ethanol/Si ratio is 1.5.However,it is difficult to synthesize ZSM-5 zeolite with a high crystallinity in a single ethanol system when Si/Al ratio is greater than 90.Also,the addition of a small amount of seed can increase Si/Al ratio of ZSM-5 zeolite synthesized in ethanol system to 150,and shorten the crystallization induction period and overall crystallization time.The morphology of ZSM-5 zeolite in seed-assisted crystallization is different from that of ZSM-5 zeolite synthesized in seed or ethanol alone,and the grain sizes are more uniform and the dispersion is higher.The optimum ratio of alkali to silicon decreases with the increase of Si/Al ratio,but it is still necessary to provide enough alkali to dissolve silicon source for crystallization.

关 键 词：ZSM-5分子筛 乙醇 晶种 水热合成 碱硅比 

分 类 号：TQ170.6[化学工程—硅酸盐工业]