【作者】 刘彩华；

【导师】 何鸣元； 杨建国；

【作者基本信息】 华东师范大学 ， 物理化学， 2008， 博士

【摘要】 介孔材料自问世以来,因具有较大的孔径、孔体积和比表面积,有利于体积较大的分子在孔道内的扩散和参与反应,因而引起人们的广泛关注。然而,纯硅的介孔材料基本没有酸性,在一定程度上限制了其在催化方面的应用。将不同的杂原子引入介孔分子筛骨架中,可以赋予介孔材料不同的催化性能,因此近年来,有关合成杂原子的介孔分子筛的研究工作被大量报道。但是采用传统的模板剂所合成某些杂原子的介孔分子筛时,某些金属杂原子难以在骨架中稳定存在,因而限制其在催化方面的应用。离子液体是在室温及相邻温度下完全由离子组成的有机液体物质,作为一种可用于绿色清洁技术和环境友好催化体系的理想介质受到了极大的关注。由于离子液体自身的特点使得其不仅在有机反应中得到了广泛的应用,在无机材料合成方面也逐渐成为人们研究的热点。本论文将离子液体作为模板剂用于介孔分子筛的合成,主要获得以下有意义的研究结果:（1）采用离子液体1-十六烷基-3-甲基溴代咪唑为模板剂合成出了多种高度有序的杂原子MCM-41介孔分子筛,如Al-MCM-41,Fe-MCM-41,Cu-MCM-41,Co-MCM-41,MgAl-MCM-41,CuAl-MCM-41。当适量引入铝金属杂原子时,铝金属杂原子能几乎全部进入介孔分子筛的骨架,并在焙烧后不会从骨架析出。本研究方法合成的Al-MCM-41,对催化p-甲酚与MTBE的烷基化反应,具有相当高的催化活性和稳定性,对甲酚转化率可达69%,2-叔丁基对甲酚选择性可达93%,并且100小时后仍保持着较好的催化活性对甲酚转化率和2-叔丁基对甲酚选择性分别为62%和92%。引入铁杂原子时,该介孔分子筛不仅具有比较大的比表面积,规则的介孔孔道结构等介孔材料的特征,而且形成了双孔道结构。由于离子液体([C₁₆mim]Br)本身特殊性。铁在Fe-MCM-41介孔分子筛骨架中相对比较稳定。另外,通过对金属含量较高的Cu-MCM-41和Co-MCM-41的表征,还发现随着金属含量的增加,样品结构的有序度下降,并且不同的金属盐对介孔分子筛的结构有一定的影响。（2）以离子液体1-十六烷基-3-甲基溴代咪唑为模板剂,以Y沸石晶种为前驱体,成功地合成出介孔分子筛Al-MSU-S。与常规模板剂十六烷基三甲基溴化铵相比,采用本离子液体为模板剂合成的介孔分子筛Al-MSU-S不仅具有较好的水热稳定性,而且具有更大的比表面、孔径和孔容。本研究还对该材料催化缩醛缩酮反应的催化性能进行了研究。结果表明Al-MSU-S是缩醛缩酮反应的良好的催化剂:该催化剂催化丁酮和乙二醇的反应时,丁酮的转化率达80.5%,丁酮缩乙二醇的选择性为99.1%。催化环己酮乙二醇的反应时,催化剂循环十次,环己酮转化率仅下降2.1%,具有很好的循环使用性。利用该离子液体也合成了含有Fe元素的FeAl-MSU-S,但是热稳定性较差,焙烧后部分结构坍塌。（3）除了1-十六烷基-3-甲基溴代咪唑,我们合成了6种新型离子液体:1-十六烷基-3-甲基羟基咪唑,1-十六烷基-3-丁基溴代咪唑,1-十四烷基-3-丁基溴代咪唑,1-十六烷基-1-甲基溴代吡咯烷酮,1-十六烷基-1-甲基溴代吗啡啉和1-十六烷基-1-甲基溴代己内酰胺,并将其应用在介孔分子筛的合成中。咪唑类的离子液体1-十六烷基-3-甲基羟基咪唑,1-十六烷基-3-丁基溴代咪唑,1-十四烷基-3-丁基溴代咪唑,虽然改变了极性头基的大小或者烷基链的长度,但仍然可以作为SiO₂合成中的模板剂,且得到的样品具有较高的热稳定性。离子液体1-十六烷基-1-甲基溴代吗啡啉在合成介孔SiO₂中也表现了很好的模板作用。而极性头基上含有C=O双键的离子液体1-十六烷基-1-甲基溴代己内酰胺和1-十六烷基-1-甲基溴代吡咯烷酮由于其离子性差,在水中比较难以电离所以无法作为模板剂用于介孔SiO₂的合成。（4）利用溶胶一凝胶法,在短链双核离子液体中合成出介孔结构的SiO₂和TiO₂。通过各种表征手段对产物进行了表征。结果表明短链的双核离子液体也能起到模板剂的作用来合成介孔结构材料,从而发展了一种合成介孔结构材料的新方法。更多还原

【Abstract】 The discovery of mesoporous molecular sieves has caused a booming research in the field.Mesoporous materials has large pore diameter,pore volume and high surface area which is benefit for the spread and part in the reaction in the mesoporous channel.However mesoporous materials with pure silica have a chemical inert silicate and consequently no active sites which district its application in catalyst.Then much attention was devoted in the synthesis of hetero-atomed mesoporous materiasl for special catalytic reactions.But the heteroatom is not stable in the framework of mesoporous materials synthesized from traditional template and this limits its application in catalytic reaction.As the medium of clean-up technology and environment friendly catalytic system,room temperature ionic liquid has attracted much attention.Roomtemperature ionic liquids are simply organic liquids that are composed entirely of ions.Not only in organic reaction,ionic liquids are also used in the synthesis of inorganic materials.In this paper,ionic liquids were used as templates in the synthesis of mesoporous molecular sieves.The main contents are as follows:（1）Heteroatomed MCM-41 were synthesized templated by 1-cetyl-3-methylimidazolium bromide,these are:Al-MCM-41,Fe-MCM-41,Co-MCM-41,Cu-MCM-41 and bimetalic MgAlMCM-41,CuAl-MCM-41.For Al-MCM-41,all aluminum in as-synthesized samples exists in tetrahedral coordination.Upon calcination nearly all aluminum still remains the tetrahedral coordination even when the Si/Al ratio is as low as 15.This indicates that the tetrahedral-alumminum of Al-MCM-41 is stable.Tert-butylation of p-cresol with methyl tea-butyl-ether（MTBE）catalyzed by HAl-MCM-41 molecular sieves was investigated.The results showed that HAI-MCM-41 was an efficient catalyst with high activity,selectivity and stability for the preparation of 2-tert-butyl-p-eresol from p-cresol and MTBE.The conversion of pcresol and selectivity for 2-tert-butyl-p-cresol are 69%and 93%respectively,62% and 92%respectively after 100 hours.Mesoporous Fe-MCM-41 was synthesized using room temperature ionic liquid 1-cetyl-3-methylimidazolium bromide([C₁₆mim]Br)as template.Mesoporous Fe-MCM-41 exhibits hexagonal p6m pore architectures,and possesses high surface area. The pore size distribution of Fe-MCM-41 shows that there are two types mesoporous. Part of iron atom still retain in the framework after removal of the template by calcination except those transferring to the wall surface.Fe species on wall surface are of high dispersion.This indicates that stable framework-iron containing mesoporous molecular sieves Fe-MCM-41 have been successfully synthesized.（2）Al-MSU-S was prepared from the precursor of Y zeolite using 1-cetyl-3-methylimidazolium bromide as a template.Except higher hydrothermal stability,Al-MSU-S also possesses higher surface area,pore diameter and pore volume comparing with that templated by CTAB.The catalytic activity of Al-MSU-S-Y was studied via the acetalization and ketalization of different aldehydes and ketones with glycol.The conversion of butanone and selectivity for are butanone ethylene ketal are 80.5%and 99.1% respectively.The conversion of cyclohexanone only dropped 2.1%after recycled 10 times.FeAl-MSU-S was also synthesized using 1-cetyl-3-methylimidazolium bromide as template with lower thermol stability.（3）Except 1-cetyl-3-methylimidazolium bromide,we synthesized six ionic liquids:1-cetyl-3-methylimidazolium hydroxy,1-cetyl-3-butyl-imidazolium bromide, 1-tetradecyl-3-butyl-imidazoliumbromide,1-cetyl-1-methylmorpholin bromide,1-cetyl-1-methyl-2-pyrrolidinone bromide and -cetyl-1-methyl caprolactam bromide. These ionic liquids were applied in the synthsis of mesoporous moleculer sieves.The results show that 1-cetyl-3-methyl-imidazolium hydroxy,1-cetyl-3-butyl-imidazolium bromide,1-tetradccyl-3-butyl-imidazolium bromide and 1-cctyl-1-methylmorpholine bromide are good templates in the synthesis ofmcsoporous SiO₂.With carbonyl in the hydrophilic group,1-cctyl-1-methyl-2-pyrrolidinone bromide and 1-cctyl-1-methyl caprolactam bromide have weak ionicity and are not soluble easily in the water.So they canot be the template in the synthesis of mesoporous materials.（4）Mcsoporous SiO₂ and TiO₂ were synthesized in ionic liquid via colloidal-gel method.The results show that short-chained dicationic ionic liquid also is good template for the synthesis of mesoporous materials.This developed a new method for the synthesis of mesoporous.更多还原