【作者】 邸岩；

【导师】 肖丰收； 李守贵；

【作者基本信息】 吉林大学 ， 无机化学， 2006， 博士

【摘要】 本论文主要开发并研究了以非离子半氟表面活性剂(FSN-100(CF₃（CF₂）5（EO）₁₄)和FSO-100 (CF₃（CF₂）₄（EO）₁₀))为模板,分别在酸性和中性条件下合成新型的介孔和超微孔材料,并研究了不同的合成条件对产品结构的影响。第一章为绪论,介绍了各种介孔分子筛的生成机理、合成路线、影响介孔材料晶相的因素以及各种不同表面活性剂对于介孔结构的决定性作用;在第二章中,利用半氟非离子表面活性剂FSN-100合成了wormlike型孔结构的介孔二氧化硅（JLU-11和JLU-12）,并通过在反应体系中添加1,3,5-三甲苯（TMB）等有机物使产品结构从无序转变为二维六方有序;第三章中重点研究了以半氟非离子表面活性剂为模板合成介孔分子筛时,产品孔径随晶化温度的变化可以从微孔调节到介孔（1.6nm～4.0nm）的现象;第四章中,我们使用半氟表面活性剂FSO-100在超低温（0 -20°C）条件下合成了超微孔二氧化硅JLU-14L,使用氟碳表面活性剂在超低温条件下制备超微孔材料,极大的拓展了介孔材料的研究领域,并且进一步显示了氟碳表面活性剂在介孔材料研究中重要性;第五章使用L沸石导向剂为原料,分别以CTAB和P123为模板剂合成了介孔硅铝分子筛MAS-3和MAS-8,与传统的Al-MCM-41和SBA-15相比,MAS-3和MAS-8都表现出了较高的水热稳定性和酸性,显示出在工业应用中的巨大潜力。更多还原

【Abstract】 Since the discovery of MCM-41 by Mobil scientists in 1992, mesoporousperiodic materials have attracted considerable attention for their potential use asversatile catalysts and supports. During the synthesis of mesoporous materials,a number of surfactants have been used as templates. Recently, it is reported thatfluorocarbon surfactants are also good templates for preparation of mesoporousmaterials.We show here disordered mesoporous silica materials with “worm-like” porestructure which were synthesized in both strongly acidic （JLU-11）and neutral（JLU-12） media using semi-fluorinated surfactant FSN-100 (CF₃（CF₂）₅（EO）₁₄).More importantly, when 1,3,5-trimethylbezene （TMB） is introduced into thesynthesis mixture, ordered mesoporous silica materials are successfully obtained.However, in our case, when a semi-fluorinated surfactant mixed with TMB isused as a template, obtained mesoporous silica materials （JLU-11（o） andJLU-12（o） samples） exhibit very similar pore size distribution with themesoporous silica materials without using TMB （JLU-11 and JLU-12 samples）.Apparently, TMB is not a swelling agent, which is quite different from thesynthesis of MCM-41 and SBA-15. Compared with hydrocarbon surfactants inaqueous solution, TMB is difficult to dissolve in the alkyl core ofsemi-fluorinated surfactants （CF）x（EO）y, because of special hydrophobic andlipophobic properties of fluorocarbon chains in the semi-fluorinated surfactant.Therefore, TMB molecules have to interact with hydrocarbon part of thesemi-fluorinated surfactant, resulting in the change in packing parameter （g） ofthe surfactant micelle, which are related to the hydrophilic-hydrophobic ratiosbetween the EO headgroups and carbon tail groups in amphiphilic blockcopolymer surfactants.Mesoporous silica-based materials （JLU-11、JLU-12、JLU-14 and JLU-15）with tailorable size are successfully synthesized by changing crystallizationtemperatures in both strongly acidic media and neutral conditions usingsemi-fluorinated surfactants(FSN-100 (CF3（CF2）5（EO）14 and FSO-100（CF3（CF2）4（EO）10）. Pore size of these materials can be changed from 1.6nm to4.0nm when the synthesis temperature is changed from room temperature to100°C. As we know, preparation of pore-controlled product is one of the purposesof mesoporous materials research. Scientists have found that when blockedoligomer is used as a surfactant, the pore size can vary regularly with thesynthesis temperature. This phenomenon is attributed to the hydrophobicity of thePEO group changes with temperature. But there is no report that control the poresize in the range of micoporous （<2nm） and mesoporous （ >2nm）, and our workbring it into practice.Ordered hexagonal smaller supermicroporous silica （JLU-14L and JLU-11L）has been successfully synthesized at ultra-low temperature （0 -20 °C） bysemi-fluorinated surfactant. Supermicrcoporous materials are very important inindustrial application because they bridge the gap of microporous zeolites andmesoporous materials. These materials are expected to have the potential of sizeand shape selectivity for those organic molecules that are too large to assess tothe pores of zeolites and are too small to be separated by mesopores. It has beenreported that synthesis temperature strongly influences the pore sizes ofmesoporous materials, and lower temperatures in the synthesis generally result inthe formation of mesoporous silica materials with smaller pore sizes. Furthermore,it is worthy to note that the samples synthesized at the ultra-low temperaturescontain uniform micropores. Such hierarchically porous materials withmicro/supermicroporosity should be potentially important for fast diffusion ofreactants and products in catalytic reactions. In conclusion, theultralow-temperature synthesis is a crucial factor for the formation of orderedsmaller supermicropores and the control of microporosity in JLU-14L.Ordered mesoporous aluminosilicates designated as MAS-3 and MAS-8 withhexagonal mesopores have been hydrothermally synthesized from preformedzeolite L precursors under alkaline and strongly acidic conditions, respectively.MAS-3 and MAS-8 show good thermal and hydrothermal stability. Catalyticresults in cracking cumene show that these mesoporous aluminosilicates are moreactive than conventional mesoporous aluminosilicates （Al-MCM-41）.Characterization of infrared （IR）, N2 adsorption isotherms, andtemperature-programmed-desorption of ammonia （NH3-TPD） have also beenused to investigate these materials and the results indicate that the walls ofMAS-3 and MAS-8 contain the primary and secondary structural building units,which might be responsible for the high hydrothermal stability and goodactivities in catalysis. Therefore, we propose that during the preparation ofMAS-3 and MAS-8, the aluminum sites are fixed in the framework of the zeoliteL nanoclusters in the first step and are introduced into the mesoporous structurewhen the nanoclusters self-assemble with the template in the second step.更多还原