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。     

Ordered Mesoporous Materials with Improved Stability and Catalytic Activity

Microporous crystals of zeolites such as Y, Beta, and ZSM-5 are widely used commercial catalysts, but their applications are strongly limited by their small pore sizes. Recent progress in solving this is used to ordered mesoporous materials such as MCM-41, HMS, and SBA-15. These mesoporous materials have pore diameters of 2.0–30 nm and exhibit good catalytic properties for the catalytic conversion of bulky reactants. However, when compared with microporous crystals of zeolites, the catalytic activity and hydrothermal stability are relatively low, which severely hinders their practical applications in industrial catalytic reactions such as petroleum cracking. The relatively low catalytic activity and hydrothermal stability can be attributed to the amorphous nature of the mesoporous walls. In this account, we systemically review the routes for improving catalytic activity and hydrothermal stability of mesoporous materials, which include (1) acidic sulfated zirconia supported in mesoporous materials; (2) strongly acidic and thermally stable mesostructured sulfated zirconia with tetragonal crystalline phase; (3) strongly acidic and hydrothermally stable mesoporous aluminosilicates synthesized in alkaline media; (4) strongly acidic and hydrothermally stable mesoporous aluminosilicates synthesized in strongly acidic media; (5) hydrothermally stable mesoporous titanosilicates with catalytically active titanium species in oxidations; (6) high-temperature generalized synthesis of ultrastable ordered mesoporous silica-based materials by using fluorocarbonhydrocarbon surfactant mixtures.     

Ti-MCM-41分子筛研究进展

介绍了Ti-MCM-41分子筛的合成方法、物性表征、表面硅烷化、负载杂原子改性研究及其近年来在催化领域的应用。Ti-MCM-41分子筛具有优异的选择催化氧化性能，还具有良好的光催化活性。可用于烃类的选择性氧化、环氧化和羟基化反应，也可作为光催化剂应用于有机物的加氢、降解反应。     

Zeolite-based materials for novel catalytic applications: Opportunities, perspectives and open problems

Zeolites and related materials (including a wide range of microporous and mesoporous materials with ordered pore structure) have been one of the areas in the field of materials and catalysis with the largest impact on science, technology and industrial processes. We discuss here some recent developments in this field, with particular references how to tailor and design zeolite and related material properties to control/enhance the catalytic performances. Four main topics have been addressed. (i) The recent progress and perspectives in the field of tailored syntheses, with selected examples showing the trend and prospects to develop new structures, control the location of active sites, and the crystal size and morphology, including nanoarchitecture of the final catalysts. (ii) The development and prospects of two-dimensional zeolites presenting an extended view/concept of zeolite structures integrating the classical 3D frameworks and the various lamellar forms. (iii) The progresses in the design and synthesis of hierarchical zeolites, with discussion on the still existing challenges related to the synthesis, characterization and catalytic application. (iv) Novel opportunities and needs in terms of zeolite multifunctional design for catalytic applications, with a discussion of the critical issues related to the use in the field of fine chemicals, organic industrial syntheses and biorefinery, and the prospects for the use in two novel challenging areas of the direct conversion of CO₂ to light olefins and methane to methanol.     

Incorporation of vanadium into the mordenite structure by direct hydrothermal crystallization and secondary synthesis

The substitution of vanadium atoms into the zeolite framework structure could be applied to the large pore zeolites by means of modified treatments as well as direct hydrothermal synthesis. The incorporation of vanadium into the mordenite framework was demonstrated by XRD, FTIR, UV-Vis techniques and tested with catalytic oxidation reactions. These vanadium-containing zeolites have selective catalytic properties in the various oxidation reactions as compared with vanadia-impregnated catalysts.     

Solid-state NMR for metal-containing zeolites: from active sites to reaction mechanism

Metal-containing zeolite catalysts have found a wide range of applications in heterogeneous catalysis. To understand the nature of metal active sites and the reaction mechanism over such catalysts is of great importance for the establishment of structure-activity relationship. The advanced solid-state NMR (SSNMR) spectroscopy is robust in the study of zeolites and zeolite-catalyzed reactions. In this review, we summarize recent developments and applications of SSNMR for exploring the structure and property of active sites in metal-containing zeolites. Moreover, detailed information on host-guest interactions in the relevant zeolite catalysis obtained by SSNMR is also discussed. Finally, we highlight the mechanistic understanding of catalytic reactions on metal-containing zeolites based on the observation of key surface species and active intermediates.     

Probing the shape selective properties of zeolites by catalytic hydrocarbon reactions

For routine applications, the effective pore widths of zeolites or zeolite-like materials can be easily characterized by suitably selected catalytic reactions. This method makes use of shape selective catalysis. Three hydrocarbon reactions for probing the pore width are comparatively discussed. They have in common that their results can be expressed in a single figure named Constraint Index (CI), Modified Constraint Index (CI*) and Spaciousness Index (SI). Recommendations for routine applications are given.     

沸石催化剂提高甲苯定向氯化的选择性

对影响合成NaL沸石催化剂的主要因素及其催化机理进行了探讨,找到了最佳工艺条件,得出了结论:NaL沸石在催化甲苯氯化反应时有极高的化学选择性;助剂无催化活性,只对具有选择催化性的沸石有助催化作用;带入反应体系的水是引起沸石催化剂失活的主要原因。     

A study on the dimerization of 1-butene over Beta zeolite

New restrictions on gasoline in some part of the world implies that oxygenates such as MTBE and aromatics should be replaced by other high-octane components. The dimerization of 1-butene, which is a step in the production of “Green” gasoline, is evaluated under liquid phase reaction conditions over acidic Beta zeolites synthesized with different synthesis time. There are substantial differences between Beta zeolites obtained at synthesis times 96 and 240 h leading to different physico-chemical properties and, furthermore, catalytic performances. More acidic Beta zeolites lead to higher yields to light olefins while less acidic samples produce more oligomers, i.e. C₁₂–C₁₄ fraction. Interestingly, it was also observed that strong acid sites catalyze cracking reactions, while the weak ones, oligomerization.     

有机合成中二芳基碘（Ⅲ）盐的应用

综述了二芳基碘（Ⅲ）盐在金属催化的交叉偶联反应、羰基化合物的a-芳基化、炔烃的芳基化、杂原子亲核化合物的芳基化等反应中的应用。     

软模板法合成多级孔沸石分子筛及其催化性能研究进展

详细介绍了软模板法合成多级孔沸石分子筛及其催化性能。合成多级孔沸石分子筛的软模板主要包括两种类型,一种是含多季铵基团的烷基季铵盐;另一种是双亲有机硅表面活性剂。对采用这两种表面活性剂合成多级孔沸石分子筛的方法以及得到的材料结构特性进行了综述。进一步讨论了这两种方法得到的分子筛的催化性能。关于这些材料的催化性能研究主要有三方面内容:有机大分子化合物合成的活性和选择性,生物质催化热解特性和大分子化合物合成中抗积炭失活性能。     

The synthetic strategies of hierarchical TS-1 zeolites for the oxidative desulfurization reactions

With the increasingly stringent standards for limiting sulfide content in liquid fuels, oxidative desulfurization (ODS) has become a promising ultra-deep desulfurization process in fuel desulfurization. TS-1 zeolites show great potential as catalysts for ODS reactions, due to its remarkable oxidation activity at low temperatures and pressure. However, the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds. Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability. In recent years, abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite, thereby improving its catalytic performance in the ODS process. This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions. In addition, some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised. We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.     

The synthetic strategies of hierarchical TS-1 zeolites for the oxidative desulfurization reactions

With the increasingly stringent standards for limiting sulfide content in liquid fuels, oxidative desulfurization (ODS) has become a promising ultra-deep desulfurization process in fuel desulfurization. TS-1 zeolites show great potential as catalysts for ODS reactions, due to its remarkable oxidation activity at low temperatures and pressure. However, the inherent microporous structure of conventional TS-1 zeolites restricts the mass transportation and renders the active sites in the microporous space of TS-1 zeolites inaccessible for bulky aromatic organosulfur compounds. Fabrication of hierarchical TS-1 zeolites by incorporating meso-/macropores into microporous TS-1 zeolites is an effective strategy to improve mass transportability. In recent years, abundant efforts have been dedicated to developing synthetic strategies of hierarchical TS-1 zeolite, thereby improving its catalytic performance in the ODS process. This mini-review addresses the synthetic methods of hierarchical TS-1 catalysts and their catalytic performance in the ODS reactions. In addition, some current problems and prospects of synthesis routes for constructing hierarchical TS-1 catalysts have also been revised. We expect this mini-review to shed light on the more efficient preparation strategies of hierarchical TS-1 zeolites for the ODS process.     

Acid-based Catalysis in Zeolites Investigated by Density-Functional Methods

Zeolites are a unique class of microporous aluminosilicates with multiple applications as molecular sieves, detergents, desiccants and acid catalysts. Their catalytic activity is determined by Br?nsted and Lewis acid sites created by protonation or activation by metallic cations. The reactivity of the acid sites is strongly influenced by the geometry and the flexibility of the zeolitic framework. Recent investigations of the reactivity of zeolites and simulations of catalytic reactions based on periodic-density-functional calculations are reviewed.     

锡硅分子筛：新型杂原子分子筛催化材料

锡硅分子筛能高效催化含氧烃转化，因此其具有重要潜在工业应用价值。本文简述了锡硅分子筛的骨架锡判定、合成方法、多级孔合成研究及应用领域。XRD、NMR和EXAFS等表征方法可以判别锡硅分子筛内锡原子的配位形式及落位。合成锡硅分子筛通常采用水热晶化法、后插入法和干胶转化法。碱性水热合成过程中匹配锡源和硅源的水解速率是使锡原子高效插入分子筛骨架的关键。中性水热合成方法制备的锡硅分子筛结晶度较高，但存在使用剧毒含氟试剂和晶粒较大等问题。干胶转化法可在短时间内制备高结晶度含锡分子筛，但该法存在传质传热差等弊端。采用后插入法可将锡原子插入到不同拓扑结构的分子筛骨架，但锡原子易发生聚集。同时，采用碱处理、硬模板剂法和软模板剂法合成多级孔锡硅分子筛，可提升骨架锡活性中心的可接近性。其中，采用软模板剂法展示出独特的优势，其可制备介孔分布均匀且贯通性良好的多级孔锡硅分子筛。另外，锡硅分子筛的骨架锡原子对含氧官能团具有优异的活化作用，因此其在Meerwein-Ponndorf-Verley-Oppenauer反应、葡萄糖异构化反应、乳酸及乳酸酯制备及Baeyer-Villiger氧化反应中都展示了良好的催化效果。     

丁烯异构化催化剂镁碱沸石的合成研究进展

在丁烯异构化反应催化剂中,镁碱沸石分子筛由于具有十元环和八元环交错的独特的二维孔道结构、良好的水热稳定性和化学稳定性、较高的选择性等诸多优点受到广泛关注;但由于有机模板剂的影响,在环境友好方面有所欠缺。本文综述了镁碱沸石（FER）的合成方法：有机模板剂合成法、非模板剂合成法、层状前体合成法、乳化剂控制合成法,归纳比较了各种合成方法的优缺点,阐述了FER的合成后处理方式,指出采用无毒无害的原材料替代有机合成模板剂,从而提高镁碱沸石分子筛的催化性能,对环境友好大大改善,是未来研究镁碱沸石分子筛催化剂的发展方向之一。     

Zeolite Beta with hierarchical porosity prepared from organofunctionalized seeds

Beta zeolite with hierarchical porosity has been obtained by a new synthesis strategy, based on perturbing the growth of the zeolite crystals by functionalization of the zeolitic seeds with organosilanes in order to hinder and prevent their further aggregation and agglomeration. As a consequence, a secondary porosity in the supermicropore region has been generated in zeolite Beta, leading to a considerable increase in both the total surface area and the pore volume of the material. The enhancement of the textural properties can be controlled by changing the silanization agent molecular size and its quantity added to the synthesis medium. This type of hierarchical Beta zeolites presents interesting applications as catalysts in reactions involving bulky molecules. Thus, their catalytic activity in the catalytic cracking of LDPE has been found to be strongly enhanced compared to a standard Beta zeolite sample, due to the higher accessibility to the acid sites caused by the presence of the secondary porosity.