高锡含量Sn-MFI分子筛的优化合成及其催化性能  

Optimized Synthesis and Catalytic Performance of Sn-MFI Zeolites with High Tin Content

作　　者：刘聿嘉 LIU Yujia(The Key Laboratory of Safety and Control for Chemicals,Research Institute of Safety Engineering,SINOPEC,Qingdao 266000,China)

机构地区：[1]中国石化青岛安全工程研究院化学品安全控制国家重点实验室,山东青岛266000

出　　处：《化学反应工程与工艺》2021年第6期481-488,共8页Chemical Reaction Engineering and Technology

摘　　要：分别以二水合二氯化锡(Sn Cl_(4)·2H_(2)O)和五水合四氯化锡(Sn Cl_(4)·5H_(2)O)为锡源,采用碱性水热晶化法制备Sn-MFI分子筛,通过X射线衍射(XRD)、透射电镜(TEM)、核磁共振(^(119)Sn MAS NMR)和吡啶红外光谱(Py-IR)等表征手段系统地考察了锡源对Sn-MFI分子筛结构、锡物种状态和酸性质的影响。结果表明:相比于Sn Cl_(4)·5H_(2)O,添加SnCl_(4)·2H_(2)O更有利于投料锡硅物质的量之比为0.025的锡硅溶胶结晶为具有MFI结构的分子筛。且相同锡投料的情况下,Sn Cl_(4)·2H_(2)O为锡源制备的Sn-MFI分子筛具有更多Lewis酸中心,其催化二羟基丙酮(DHA)制备的乳酸甲酯(ML)收率更高。其中,投料锡硅物质的量之比为0.015的Sn-MFI分子筛在80℃催化DHA反应9 h,ML收率最高可达77.4%。同时,催化剂稳定性优良。Tin-containing MFI-typed zeolites were synthesized by hydrothermal method using SnCl_(4)·5H_(2)O and Sn Cl_(4)·2H_(2)O as tin sources.The effects of different tin sources on the structural information,tin cooperation state and acid property of Sn-MFI zeolites were systematically characterized by X-ray diffraction (XRD),transmission electron microscope (TEM),nuclear magnetic resonance (^(119)Sn MAS NMR)and pyridine Fourier infrared spectroscopy (Py-IR).Compared to SnCl_(4)·5H_(2)O,tin-silicon sol (feeding with molar ratio of Sn to Si over 0.025) were easily crystallized to zeolites with MFI topology structure using SnCl_(4)·2H_(2)O as tin source.And Sn-MFI zeolites with the utilization of SnCl_(4)·2H_(2)O had more Lewis acid centers,resulting in better catalytic performance on dihydroxyacetone (DHA) conversion to methyl lactate(ML).Among them,Sn-MFI zeolite with molar ratio of Sn to Si 0.015 showed the best activity with ML yield of 77.4%under specific reaction conditions (80℃,9 h) and excellent stability during its life-testing experiment.

关 键 词：二水合二氯化锡 Sn-MFI分子筛 结晶 骨架锡原子 Lewis酸中心 乳酸甲酯 

分 类 号：O643.36[理学—物理化学]