硅源对MCM-22分子筛合成及物化性质的影响  

Effect of silicon source on synthesis and physicochemical properties of MCM-22 zeolite

作　　者：杨卫亚 凌凤香 张喜文 王少军 杨春雁 沈智奇 郑庆华 YANG Wei-ya;LING Feng-xiang;ZHANG Xi-wen;WANG Shao-jun;YANG Chun-yan;SHEN Zhi-qi;ZHENG Qin-hua(Dalian Research Institute of Petroleum and Petrochemicals,SINOPEC,Dalian 116045,China)

机构地区：[1]中国石油化工股份有限公司大连石油化工研究院,辽宁大连116045

出　　处：《燃料化学学报》2020年第7期883-888,共6页Journal of Fuel Chemistry and Technology

摘　　要：在动态水热条件下,研究了硅溶胶、白炭黑、硅酸及硅胶为硅源时对MCM-22分子筛合成及物化性质的影响。以硅溶胶、白炭黑、硅酸三种硅源均可合成出高结晶度且无杂晶的片状MCM-22分子筛,其平均粒径分别为190、220和750 nm。硅源影响分子筛的聚集形态,三种硅源分别形成晶粒分散、晶粒半分散及晶粒聚集形态。三组样品的酸强度分布基本一致,都具有较多的中强酸分布,由硅溶胶和硅酸所得MCM-22分子筛在中强酸范围具有更高的B/L酸比值,以白炭黑合成的分子筛总酸量最高。NMR结果表明,样品中的铝以骨架铝为主,不存在明显的非骨架铝。由于硅胶对合成体系中游离水的吸附作用,水热反应难以发生,不能得到MCM-22分子筛,硅胶作为分子筛合成硅源时需要选择合适的反应条件。The effects of silicon source on the synthesis and physicochemical properties of MCM-22 zeolite were studied by using silica sol,fumed silica,silicic acid and silica gel as synthesis materials under dynamic hydrothermal conditions.MCM-22 zeolite with high crytallinity and purity was synthesized by using silica sol,silica,silicic acid and silica gel as silicon sources.The average sizes of zeolite particle are 190,220 and 750 nm,respectively.Three silicon sources can affect the aggregate morphology of the zeolites,which are grain dispersion,grain semi dispersion and grain aggregation.The distribution of acid strength of the three groups of samples are almost same,all of them have more medium and strong acidity,and the total acid content of zeolite synthesized by fumed silica is the highest.MCM-22 obtained from silica sol and silicic acid has higher B/L acid ratios in the range of medium strong acid.The results of NMR show that the main aluminum in the samples is skeleton aluminum without obvious non-skeleton aluminum.MCM-22 zeolite can not be obtained when silica gel is used as silicon source because silica gel can adsorb the free water in the preparation system,suppressing the hydrothermal reaction.The reaction conditions should be carefully set up when silica gel is used as silicon source to prepare zeolite.

关 键 词：硅溶胶 白炭黑 硅酸 分子筛 MCM-22 

分 类 号：O641[理学—物理化学] O649[理学—化学]