以CTMABr和CTMAOH为共模板剂合成MCM-41

采用共模板剂水热合成了MCM-41.分别用X射线粉末衍射(XRD)、固体核磁共振(²⁷AlMASNMR)和N₂吸附等温线技术考察了用该方法和传统方法所制备的Si-MCM-41和Al-MCM-41样品的晶相结构、孔结构以及Al在分子筛中的化学环境.结果表明,用共模板剂方法合成的MCM-41样品,其纯度和孔径均一性显著提高,特别是当样品中Al含量较高时,仍可保证Al原子以四配位结合在MCM-41的硅骨架上.还就采用共模板剂的理论依据进行了讨论.     

以MCM-22为原料合成高水热稳定性的介孔材料

以合成的微孔分子筛MCM-22为原料,将其与表面活性剂及氢氧化钠一起回流溶解,再调节溶液的pH值至7～9, 使MCM-22转化为高水热稳定性的介孔材料. 所得介孔材料具有蠕虫状的均匀孔道,骨架中不含有MCM-22的微观结构单元. 该介孔材料至少含有18%的表面活性剂,经823 K焙烧脱除表面活性剂后,其孔径为2 2 nm, 比表面积为 1 038 m2/g, 孔容为0 97 cm3/g. 焙烧后的介孔材料具有非常高的水热稳定性,经沸水回流100 h后其比表面积为896 m2/g, 孔容为0 90 cm3/g, 孔径为2 1 nm, 即使经过300 h的回流,该材料仍能保持698 m2/g的比表面积和0 90 cm3/g的孔容. 固体 29Si MAS NMR结果表明,该介孔材料的高水热稳定性与其高表面缩合度有关.     

Synthesis of hydrothermally stable and long-range ordered Ce-MCM-48 and Fe-MCM-48 materials

The hydrothermally stable and long-range ordered Ce-MCM-48 and Fe-MCM-48 were conveniently synthesized at 393 K for 24 h by directly adding fluoride ions to the initial gel without posttreatment and pH adjustment. The Ce-MCM-48 with a Si/Ce of 200 and 100, which were prepared by directly adding fluoride ions, could still maintain their mesoporous structures after refluxing in boiling water for 3 days. The incorporation of Ce into MCM-48 could enhance the hydrothermal stability of MCM-48 in the absence of fluoride ions; however, the incorporation of Fe into MCM-48 materials barely improved the hydrothermal stability of MCM-48 materials. The effect of adding NaF was much more efficient in enhancement of hydrothermal stability than that of the incorporation of Ce. The addition of fluoride ions mainly improves the degree of polymerization of silicates. The Ce(4+) ions in Ce-MCM-48 appear to be present partly in tetrahedral coordination in the framework and partly as CeO(2) particles on the surface of framework. The Ce positioned on the surface of pore walls and in the framework both provide the protection against water attack.     

模板剂对全硅MCM-41介孔分子筛结构的影响

分别采用十六烷基三甲基溴化铵和十六烷基三乙基溴化铵作为模板剂,硅溶胶为硅源,用水热晶化法在碱性（NaOH）介质中合成了MCM-41介孔分子筛样品.通过XRD、N2吸附-脱附、TG-DTA、IR等测试手段对这两种样品进行了对比表征分析.考察了两种不同模板剂对其晶体结构、比表面及孔径大小的影响.实验结果表明,相对于十六烷基三甲基溴化铵做模板剂,采用大头基的十六烷基三乙基溴化铵可以合成较大孔径和孔容（分别为4.72 nm和1.14 cm3•g-1）的MCM-41介孔分子筛,而且具有较窄的孔径分布,因此对于合成大孔径的介孔分子筛MCM-41,十六烷基三乙基溴化铵是一种很好的模板剂.     

具有强酸性位的高水热稳定介孔分子筛的合成

在强酸性介质中,以预先制备的β沸石纳米簇作为前驱体,通过S＋X－I＋路线及氨水热后处理步骤合成具有强酸性位的高水热稳定性介孔分子筛.XRD、氮气吸附、HRTEM和SEM分析表明所得样品具有普通MCM-41的典型介孔结构和表观形貌.较短的组装周期和室温的组装条件减弱了脱铝效应,27Al MAS NMR表明铝元素主要以四配位状态存在于介孔分子筛骨架中.采用NH3-TPD和水热老化方法分别考察了其固体酸性和水热稳定性,结果表明此介孔分子筛相对于普通MCM-41分子筛具有较强酸性位和较高的水热稳定性.沸石纳米簇的引入提高了分子筛骨架的聚合度和孔壁的厚度,是水热稳定性提高的主要原因.     

高硅分子筛MCM-41热稳定性与水热稳定性的初步研究

高硅分子筛ＭＣＭ－４１热稳定性与水热稳定性的初步研究董维阳,龙英才,郜晓琴,许太明,谢关根,高滋（复旦大学化学系,上海,２００４３３）关键词高硅分子筛ＭＣＭ－４１,热稳定性,水热稳定性,环己烷吸附等温线ＭＣＭ－４１是最近几年刚刚发现的中孔分子筛（Ｍ４...     

Synthesis of Beta/MCM-41 composite molecular sieve with high hydrothermal stability in static and stirred condition

Beta/MCM-41 micro/mesoporous composite materials have been prepared through assembly of zeolite Beta nanoclusters and their hydrolysis products in the presence of CTAB under static or stirred conditions. The resulting materials were characterized by powder XRD, TEM and nitrogen adsorption-desorption. Hydrothermal stability of the obtained Beta/MCM-41 composites was evaluated by boiling in distilled water for different periods of time under refluxing. All materials exhibit very high hydrothermal stability.     

中孔沸石新材料MCM－41──Ⅰ．合成、酸性及稳定性

中孔沸石新材料ＭＣＭ－４１──Ⅰ．合成、酸性及稳定性赵修松，王清遐，徐龙伢，谢紊娟（中国科学院大连化学物理研究所，大连１１６０２３）李新生（中国科学院大连化学物理研究所催化基础国家重点实验室，大连１１６０２３）关键词ＭＣＭ－４１沸石，合成，酸性，稳定...     

Characterization of methylated nanoscale MCM-41 material

In this study, nanoscale MCM-41 molecular sieve was prepared under a basic condition by a hydrothermal method using cetyltrimethylammonium bromide as a template and tetraethyl orthosilicate as a silica source. Methylated nanoscale MCM-41 molecular sieve was prepared from the nanoscale MCM-41 by post-synthesis method using trimethylchlorosilane (TMCS) as coupling agent. The product was characterized by means of element analysis, powder X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy, low-temperature nitrogen adsorption-desorption technique at 77 K, scanning electron microscopic (SEM), thermogravimetry-differential thermal analysis (TG-DTA). Powder XRD showed that the framework of the molecular sieve was well retained and the degree of ordering of the methylated MCM-41 decreases. IR spectra and the low-temperature nitrogen adsorption-desorption technique suggested that methyl was successfully grafted to the inner surface of the methylated MCM-41 and the mesoporous channels of the methylated MCM-41 were still maintained. Scanning electron microscopic results showed that the average size of the methylated MCM-41 prepared was 112 nm. Differential thermal analysis showed that the prepared material has preferable thermal stability and the methylated MCM-41 can be stable at 903 °C.     

高骨架铝含量Al-MCM-41的合成

制备了不同Al含量的Al-MCM-41试样，其中Si/Al比值最小为3，即最高含铝量x~A~l=0.303。X射线粉末衍射(XRD)分析表明样品具有MCM-41的特征结构，氮气吸附研究表明，样品呈现Ⅳ型吸附等温线，具有孔径分布均一的中孔结构。文中还利用^2^7AlMASNMR研究了试样中Al的化学环境，结果表明，即使在高铝含量的情况下，样品中的铝原子仍以四配位结合在MCM-41的硅骨架上，未能检测出骨架外六配位铝的存在。文中还就Al含量对孔结构的影响以及Al-MCM-41形成机理作了讨论。     

纳米介孔分子筛MCM-41的微波辐射合成法

报导了纳米介孔分子筛MCM-41的微波辐射合成法,运用XRD、HRTEM、IR、TG、荧光光谱和低温N2吸附等技术对其进行了表征.研究结果表明,利用微波技术合成MCM-41,操作便利,节能省时.所得产物具有六方介孔排列结构,孔径约2.5 nm;颗粒大小分布均匀,平均粒径约40 nm;比表面积和孔隙率高,吸附量大,热稳定性好;在近紫外光激发下,显示出纳米粒子的量子发光效应.     

锌锡双金属掺杂MCM-41的合成及表征

以硅酸钠为硅源, 锡酸钠，硝酸锌为金属源，十六烷基三甲基溴化铵为模板剂，采用直接水热合成法合成出了锌锡双金属同时掺杂的介孔MCM-41。通过ICP﹑XRD、TG-DTA﹑FTIR﹑HRTEM以及BET等技术对材料的结构和性质进行了表征。结果表明，合成的材料具有典型的六方介孔结构，比表面高，孔分布窄，热稳定性较高，且锌锡可能进入介孔MCM-41骨架中。该材料对苯酚羟基化反应具有良好的催化性能，双金属修饰MCM-41催化活性明显优于单组分掺杂。     

锡掺杂超微孔二氧化锆的合成及表征

The super microporous tin-doped zirconium oxides were successfully synthesized by sol-gel method using zirconyl chloride as Zr source, tin chloride as Sn source and cetyltrimethylammonium bromide （CTMAB） as template under hydrothermal or refluxing conditions. The structures of the resultant materials were characterized by XRD, BET, FTIR, TG-DTA, XRF and HRTEM techniques. Experimental results indicated that the framework of the samples is typically ordered hexagonal structure. The surface area and pore volume of the materials prepared by refluxing method were larger than by hydrothermal method, but the ordering of pore distributions is lower. The thermal stability of the samples was relatively high （〉773 K） and decreased with the increment of tin content.     

Effect of auxiliary chemicals on preparation of silica MCM-41

Silica MCM-41 materials were prepared hydrothermally by using 1,3,5-trimethylbenzene (MS) or 1,3,5-triisopropylbenzene (TI) as an auxiliary chemical. The BJH poressize of MCM-41 increased up to 12 nm with increasing amounts of MS. However, MCM-41 materials prepared with MS displayed irregular pore arrangements and a half of these materials exhibited low thermal and hydrothermal stabilities. On the other hand, MCM-41 materials prepared with TI as an auxiliary chemical displayed regular pore arrangements and high thermal and hydrothermal stabilities, but their BJH pore sizes did not go over 4.0 nm (intrinsic value; ca. 5 nm). MCM-41 prepared with TI together with a small amount of MS (TI/MS/SiO₂=1.5/0.5/1) displayed regular pore arrangements and high thermal and hydrothermal stabilities. Its BJH pore size was 4.7 nm (intrinsic value; ca. 6 nm).     

AlMCM-41介孔分子筛的合成及表征

以拟薄水铝石为铝源、水玻璃为硅源、十六烷基三甲基溴化铵为模板剂,在110℃时水热晶化合成了含Al的MCM-41介孔分子筛.采用X射线衍射(XRD)、N2吸附-脱附、固体29Si、27Al魔角旋转核磁共振技术(MASNMR)、扫描电镜(SEM)及吡啶吸附傅里叶变换红外(FTIR)光谱技术对AlMCM-41分子筛进行了表征.结果表明:AlMCM-41分子筛具有六方排列的孔道结构,同时具有很高的相对结晶度、比表面积和孔容,且孔分布单一;AlMCM-41分子筛中Si原子在骨架内键合的程度更高,使AlMCM-41分子筛具有更好的骨架晶化程度;同时具有四配位骨架铝,使AlMCM-41介孔分子筛具有适当的酸性.     

辅助有机胺对介孔分子筛MCM-41合成及其性质的影响

采用阳离子表面活性剂十六烷基三甲基溴化铵为模板剂、硫酸铝为铝源、硅溶胶为硅源，分别使用中等链长的有机胺和正己烷作为辅助添加剂，用水热晶化法在碱性介质中合成了介孔分子筛MCM-41，通过XRD、N2吸附-脱附、SEM测试手段对得到的样品进行了对比表征分析。实验结果表明，除三乙胺外，向反应体系中加入适量的三正丙胺、三正丁基胺、三正辛胺和二异丁胺后，均能够使介孔 MCM-41的d100值和孔径增大，且具有较大的BET表面积（>1 000 m2/g）和孔容（>1 cm3/g）；加入正己烷后，也可以使得MCM-41孔径变大，但是和加入有机胺相比较，合成的样品具有较小的BET表面积（887.3 m2/g）和孔容（0.81 cm3/g）。     

Large Pore Mesoporous MCM-41 Templated from Cetyltriethylammonium Bromide

Following hydrothermal synthesis process, MCM-41 was synthesized by using cetyltfiethylammonium bromide as templating agent. The experimental results showed that MCM-41 with pore diameter in the range of 4-7 nm can be obtained by adjusting nSurf./nSi. It was proved that cetyltriethylammonium bromide is an effective templating agent for increasing pore diameter of molecular sieve MCM-41.     

磺酸基功能化MCM-41有机-无机杂化材料的合成与表征

 利用直接合成法和后接枝法将含有磺酸基团的硅烷偶联剂引入MCM-41介孔分子筛中, 合成了酸性介孔有机-无机杂化材料. 利用XRD和TEM等方法对其结构进行了表征. 结果表明,利用直接合成法和后接枝法合成的杂化材料仍保持规整的介孔孔道,该材料作为酸催化剂在苯甲醛与乙二醇的缩醛反应中显示了较好的催化活性.     

Strong Acidic and High Temperature Hydrothermally Stable Mesoporous Aluminosilicates with Well-ordered Hexagonal Structure

Mesoporous molecular sieves such as hexagonally ordered MCM-41 have been attracted many researchers' attention since they are potentially used as versatile catalysts and catalyst supports for conversion of large molecules. However, as compared with those of zeolites, the acidity and hydrothermal stability of these mesostructured materials are relatively low, which strongly influence their practical applications in industrial catalytic reactions of petroleum. Despite several successful examples of preparation on the stabilization of aluminosilicate mesostructures at low temperature (in boiling water,100℃) including syntheses of materials with thick pore walls by triblock copolymers, removal of silanol groups by silylation, addition of salts effects,and post-treatments, their acidity and hydrothermal stability at high temperature (800℃) are still lower than those of microporous aluminosilicate zeolites.     

Synthesis and Characterization of Ce-Containing MCM-41

SUMMARY. The cerium-containing MCM-41 (Ce-MCM-41) has been synthesized with size in the micrometer range by direct hydrothermal method. Transmission electron microscopy shows the regular hexagonal array of uniform channel characteristics of MCM-41. Five peaks were detected in the lov-angle XRD patterns,an interplanar spacing d100 = 40.6 A was obtained that can be indexed on a hexagonal unit cell with a0 = 46.9 A. Nitrogen adsorption isotherm at 77 K revealed a surface area of 920 m2/g, pore size of 26.2 A and wall thickness of 18.1 A. A cell contraction of 2.6 A upon calcination was observed. The spectroscopic studies indicate that the synthesized sample is with MCM-41 structure and Ce is in the framework position. A weak Lewis acidity was indicated by infrared spectra of pyridine adsorption. The synthesized Ce-MCM-41 exhibits fairly catalytic activity for the NO reduction by CO.