介孔ZSM-5分子筛材料的制备及催化应用研究进展

介孔沸石分子筛具有沸石优良的水热稳定性、酸性和择形性,并兼具介孔的传质优势,使反应物更易接触到催化剂内表面活性中心,从而提高材料的催化活性,所以,介孔沸石分子筛近年来得到大量研究.综述了介孔ZSM-5沸石分子筛的制备方法,主要评述了模板法和后处理改性法;介绍了该催化材料在裂化、芳构化、异构化及烷基化过程中的应用;指出了介孔ZSM-5分子筛的发展方向.     

由沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的新型介孔分子筛材料

人们合成了一系列介孔分子筛材料,并发现它们在催化、吸附与分离以及化学组装制备先进材料和分子器件等方面具有很大的潜在应用价值.但是,介孔分子筛材料相对于微孔沸石分子筛存在着两个致命弱点:较低的水热稳定性和较不活泼的催化活性中心.这两个弱点大大地影响了介孔分子筛在催化反应中的广泛应用.本文系统地综述了最近几年利用沸石纳米粒子自组装制备具有高催化活性中心和水热稳定的介孔分子筛材料的研究进展.这包括利用硅铝沸石纳米粒子自组装制备具有强酸性和水热稳定的新型介孔硅铝分子筛材料,利用钛硅沸石纳米粒子自组装制备具有高催化氧化活性中心和水热稳定的新型钛硅介孔分子筛材料,以及利用含有不同杂原子的沸石纳米粒子自组装制备一系列水热稳定的新型介孔分子筛催化材料.     

多级孔沸石分子筛的制备及其催化应用研究进展

多级孔沸石分子筛在保留了微孔沸石优异的催化活性与择形性的同时,能够从本质上大幅提升沸石分子筛的传质与扩散效率,改善催化剂因积炭问题失活较快的弊端。本文介绍了当前阶段多级孔沸石分子筛的研究现状,主要基于孔径大小的差异,重点综述了微孔-介孔、微孔-大孔以及微孔-介孔-大孔三类具有多级孔道结构的沸石分子筛在制备及催化应用方面的最新研究进展,综合分析了各种制备方法在性能、成本、可操作性及应用上的利弊关系,并且指出,设计并可控地制备出具有多级孔道结构且在三维空间高度贯通的多级孔沸石分子筛材料以最大限度地提高催化效率,将会是未来多级孔沸石分子筛领域的研究重点。     

碱处理制备介孔-微孔沸石分子筛的影响因素及其应用研究进展

综述了碱处理制备介孔-微孔沸石分子筛的影响因素,包括碱处理条件、沸石分子筛硅铝比和模板剂对碱处理脱硅形成介孔的影响。评述了碱处理所制备介孔-微孔沸石分子筛在应用方面所取得的进展,重点介绍了它们在烷基化、异构化、裂化和醇烃化等催化反应中的应用。通过碱处理引入介孔可极大地缩短分子在沸石微孔道中的扩散距离,从而增强表观催化反应活性及提高催化剂的稳定性。提出了今后研究的重点为：阐明碱处理引入介孔的形成机理和碱处理对分子筛骨架结构、酸性的影响,拓展碱处理制备介孔-微孔沸石分子筛的应用 范围。     

饱和ATP为原料合成多级孔ZSM-5沸石分子筛的制备与表征

研究以饱和ATP吸附材料为合成沸石分子筛的硅源,采用双模板法,用四丙基氢氧化铵(TPAOH)为微孔模板剂和十六烷基三甲基溴化烷(CTAB)为介孔模板剂直接合成多级孔ZSM-5沸石分子筛,通过XRD、SEM、比表面积及孔径分析仪进行N2吸附-脱附等手段对多级孔ZSM-5沸石分子筛表征测试分析。结果表明,饱和ATP吸附材料在180℃下,水热提纯12 h获得硅源,再加入TPAOH和CTAB进行初始凝胶反应,后移入水热反应釜中,控温180℃,水热晶化反应15 h,即得多级孔ZSM-5沸石分子筛。     

13X微孔沸石和MCM-41介孔材料的合成及用于处理含Cd2+废水

以天津蓟县钾长石矿粉为主要原料,经选矿、煅烧、水热处理等工艺成功合成了13X微孔沸石. 以气相氧化硅、氢氧化钠、十六烷基三甲基溴化铵等为主要原料,在水热条件下合成了MCM-41有序介孔材料. 采用XRD和N2吸附-脱附等手段对合成的13X沸石和MCM-41介孔材料的物相、比表面积、孔径、孔体积等进行了分析对比. 在此基础上,对13X沸石和MCM-41介孔材料处理含Cd2+废水的效果和机理进行了对比研究,确定了不同分子筛用量、不同初始pH值、不同混合时间下13X沸石和MCM-41介孔分子筛对水中Cd2+的吸附率和吸附量. 研究发现,尽管MCM-41的比表面积和孔径远大于13X沸石,但其对水中Cd2+的处理效果却低于13X沸石,这与13X沸石和MCM-41的孔道结构类型、化学组成、表面荷电性质等有关.     

饱和ATP为原料合成多级孔ZSM-5沸石分子筛的制备与表征

研究以饱和ATP吸附材料为合成沸石分子筛的硅源,采用双模板法,用四丙基氢氧化铵(TPAOH)为微孔模板剂和十六烷基三甲基溴化烷(CTAB)为介孔模板剂直接合成多级孔ZSM-5沸石分子筛,通过XRD、SEM、比表面积及孔径分析仪进行N2吸附-脱附等手段对多级孔ZSM-5沸石分子筛表征测试分析。结果表明,饱和ATP吸附材料在180℃下,水热提纯12 h获得硅源,再加入TPAOH和CTAB进行初始凝胶反应,后移入水热反应釜中,控温180℃,水热晶化反应15 h,即得多级孔ZSM-5沸石分子筛。     

新型多级孔ZSM-5沸石分子筛制备与研究

本研究通过在传统ZSM-5沸石分子筛的基础上引入有机硅烷季铵盐作为介孔导向模板剂制备了四种新型多级孔ZSM-5沸石分子筛。利用XRD、N2吸附脱附、SEM、TEM进行结构表征,结果表明以十四烷基双氨基甲酸酯基有机硅烷季铵盐作为介孔模板剂,所制得的ZSM-5-L2新型多孔级分子筛表面结晶度较好,SEM图为椭圆形颗粒,晶体表面密集粗糙,具有有序的介孔孔道,介孔孔道占总孔容的比例相对于其他样品更大,且介孔孔道约为4.0 nm左右,满足企业对材料改性及提升性能的需求。     

有机官能化介孔硅基材料研究综述

介孔硅基材料的出现,使沸石中难以完成的大分子催化、吸附和分离过程变为可能。通过对介孔分子筛进行物理及化学改性,可以对其表面性质（内表面及外表面）和孔大小进行精确的控制,同时还可以增强其水热稳定性。改性后的介孔分子筛在大量的催化反应及吸附过程中表现出了比纯硅介孔材料更好的活性、选择性及稳定性。本文拟对介孔硅基材料的合成机理、有机官能化介孔硅基材料在合成与应用方面的研究进展作一简要综述。     

多级孔沸石分子筛在芳烃烷基化反应中的研究进展

多级孔沸石分子筛不仅具有微孔沸石固有的高水热稳定性和强酸性,且兼具介孔以及大孔材料的传质优势,提高了表面活性位的有效利用率,在多相催化领域表现出良好的催化性能。本文详细阐述了近年来多级孔沸石在芳烃烷基化反应中的研究进展,讨论了多级孔沸石分子筛中介孔的存在对芳烃烷基化特别是其中包含有较大分子参与的烷基化催化反应的促进作用,从分子扩散和可接近性两方面解释了多级孔沸石对催化活性、选择性和稳定性的促进作用。同时指出制备具有高度有序结构的介孔沸石,并深入研究多级孔沸石的酸性,建立沸石酸性能、孔结构与催化性能之间的关联是未来多级孔沸石的研究方向。     

Perspectives of Micro/Mesoporous Composites in Catalysis

This article covers the recent development in the remarkably growing field of synthesis, characterization and particularly catalytic investigation of zeolite‐based materials combining micro‐ and mesoporous features. New synthetic approaches for preparation of micro/mesoporous composites including recrystallization of originally amorphous matter, utilization of nanocrystalline zeolite seeds and formation of mesoporous zeolite single crystals are the first focus of this article. The advantages and disadvantages of composite materials in comparison with pure micro‐ and mesoporous molecular sieves will be discussed, as well. The relevance of individual experimental techniques for analysis of the composites, i.e., their structure, porosity, chemical composition, morphological features, and so on, are described in the second section of the article. The last Section is focused on the application of micro/mesoporous composites and mesoporous zeolites as catalysts in acid‐catalyzed reactions, oxidation reactions and synthesis of fine chemicals. The potential of the composites in challenging areas of catalysis for future applications is the final objective of the review.     

Perspectives of Micro/Mesoporous Composites in Catalysis

This article covers the recent development in the remarkably growing field of synthesis, characterization and particularly catalytic investigation of zeolite-based materials combining micro- and mesoporous features. New synthetic approaches for preparation of micro/mesoporous composites including recrystallization of originally amorphous matter, utilization of nanocrystalline zeolite seeds and formation of mesoporous zeolite single crystals are the first focus of this article. The advantages and disadvantages of composite materials in comparison with pure micro- and mesoporous molecular sieves will be discussed, as well. The relevance of individual experimental techniques for analysis of the composites, i.e., their structure, porosity, chemical composition, morphological features, and so on, are described in the second section of the article. The last Section is focused on the application of micro/mesoporous composites and mesoporous zeolites as catalysts in acid-catalyzed reactions, oxidation reactions and synthesis of fine chemicals. The potential of the composites in challenging areas of catalysis for future applications is the final objective of the review.     

中孔分子筛材料的研究进展

介绍了中孔分子筛MCM系列、HMS系列、MSU系列、SBA系列等在合成方法和改性方法上的研究进展;评述了掺入杂原子、引入有机基团、硅源前处理、混合模板剂等赋予中孔分子筛新的催化性能和选择性氧化性能及其应用前景。     

沸石分子筛的性能与应用研究

近年来,沸石分子筛由于具有独特的性能,已经在吸附分离、催化等领域取得了广泛的应用。介绍了沸石分子筛的性能及其在干燥和净化领域、吸附分离、催化领域的应用。对沸石分子筛的研究提出几点建议:1)研制价格低廉的沸石分子筛;2)研究沸石分子筛的合成及改性,提高其吸附容量和选择性;3)建立和完善评价吸附剂性能的定量指标。     

Mesoporous Material from Zeolite

Zeolite/mesoporous molecular sieve composites (ZMC) are made using zeolites as silica-alumina source. XRD patterns of the ZMC show the peaks for both zeolite and mesoporous molecular sieve with hexagonal symmetry. Morphology of the ZMC is different from that of a physical mixture of the two components. Unlike Al-containing mesoporous molecular sieves, the ZMC shows a strong acidity like zeolites. The activity of cracking of n-hexane for ZMC was higher than that of the zeolite. These products are expected to be useful for catalysts and adsorbents for their acidity and pore size.     

AI-SBA-15介孔分子筛的制备及应用进展

介孔分子筛SBA-15通过化学改性,可将一些官能团引入到其骨架中改善催化性能,其中以铝改性效果最好,铝改性后的SBA-15介孔分子筛的水热稳定性及酸性明显提高。介绍了A1-SBA-15介孔分子筛的合成及应用现状,展望了介孔分子筛A1-SBA-15未来的发展方向。     

Water adsorption and desorption isotherms of silica and alumina mesoporous molecular sieves

Mesoporous molecular sieves of silica, and alumina, and porous materials of titania, zirconia, and niobia were synthesized by cationic and/or neutral templating methods. These porous materials were characterized by powder X-ray diffraction, transmission electron microscopy, N₂ adsorption-desorption isotherms and water adsorption-desorption isotherms. Mesoporous molecular sieves of silica with surface areas of 956 and 1072 m²/g and of alumina with surface area of 407 m²/g were synthesized. The Ti₁ Zr and Nb oxide porous materials, however, showed smaller surface areas of 258, 178, and 77 m²/g, respectively, after calcination at 300°C and exhibited only small peaks for mesopores as determined by the pore-size. distributions.Water adsorption-desorption isotherms of silica and alumina mesoporous molecular sieves showed Type V (weak interaction) and Type IV isotherms, respectively. The property of sudden filling of mesopores in theP/P ₀ range of 0.45 to 0.55 in silica mesoporous molecular sieves with well-defined hysteresis during desorption, can be used in the design of humidity sensors. The titania, zirconia and niobia porous materials showed Type I water adsorption-desorption isotherms which suggests that these are mainly microporous. These results suggest that water adsorption-desorption isotherms provide valuable information about mesoporous molecular sieves for their potential use as humidity sensors.     

纳米介孔分子筛的合成及催化应用研究进展

具有纳米级颗粒尺寸的介孔分子筛因其双纳米性质,不仅具有传统介孔分子筛大比表面积、规整孔道结构的特点,而且具有性能优良的纳米级颗粒尺寸,在大分子有机物的催化反应中具有更好的应用潜力。主要介绍了纳米介孔分子筛的合成进展及其在催化领域的应用概况,同时也对未来的发展状况和应用前景作了预测和展望。     

不同方法合成铈掺杂介孔分子筛的结构性能

以硅酸钠、硝酸铈铵为原料,十六烷基三甲基溴化铵为模板剂,分别在微波辐射和水热条件下,合成稀土元素铈掺杂的介孔分子筛（CeMCM-41）。采用X射线粉末衍射（XRD）、透射电子显微镜（TEM）、紫外–可见分光光度计（UV–vis）和N2吸附-脱附等技术对合成的样品进行表征,研究了2种不同方法合成的CeMCM-41的介孔有序性和结构性能。结果表明：在2种不同的合成条件下,成功合成出铈掺杂的MCM-41介孔分子筛,其比表面积高于800 m2/g。合成条件影响着所合成的介孔材料的结构性能。     

Recent Advances in Catalysis Over Mesoporous Molecular Sieves

This overview covers the recent achievements in the application of mesoporous molecular sieves as catalysts and catalyst supports. Main structural and textural features are outlined in relation to the novel synthesis approaches of mesoporous molecular sieves and understanding of their properties. For application of mesoporous molecular sieves as catalysts different ways of introduction of active sites on their surfaces are provided. The main part describes selected catalytic reactions catalyzed by mesoporous molecular sieves focused on very recent papers. The examples include metathesis, acylation reactions, C–C coupling reactions of Heck and Suzuki types, base-catalyzed reactions (Knoevenagel and Michael additions, Claisen-Schmidt condensation, Tischenko reaction) and last but not least immobilization of organometallic complexes for different catalytic applications including chiral catalysts.