高通量筛选技术在多相催化研究中的应用

通过对组合催化研究的关键因素－－催化剂高通量筛选技术的评价分析认为：在对已有的催化体系和催化剂优化的同时,如何高校研制开发新筛选检测技术,诸如反应器设计和检测器的选择,是组合催化研究的主导思想,对此的深刻理解和运用将增强实验室的创新能力。     

Catalysis in Energy Generation and Conversion: How Insight Into Nanostructure, Composition, and Electronic Structure Leads to Better Catalysts (Perspective)

Catalysts are essential for the generation of energy carriers like hydrocarbon fuels, hydrogen, and electrical current. The performance of catalysts can be related to their nanostructure (i.e., size and shape) and composition. To rationally design catalysts by tuning these properties, they should be measured in a meaningful way using surface-sensitive spectroscopic tools under reaction conditions. In this perspective, we provide case histories of recently published research aimed at understanding these properties using a spectroscopic strategy under reaction conditions. We limit this perspective to studies whose main focus was to understand how the nanostructure and composition impact the active phase and/or efficiency of catalysts for the generation and conversion of energy carriers. We discuss studies of a Pd/Ga₂O₃ catalyst for the generation of hydrogen fuel from methanol and water, a PtMo catalyst for the generation of hydrogen fuel from biomass and water, Pt/Rh catalysts for the conversion of hydrogen into electrical current, a CeO _x catalyst for the conversion of hydrogen into electrical current, and Fe and Co/CoPt catalysts for the generation of hydrocarbon fuel from carbon monoxide and hydrogen. Each study emphasizes how the use of spectroscopic tools under reactive conditions is beneficial for making rational decisions for improving catalysts. The studies demonstrate how different synthesis methods dictate the nanostructure and distribution of alloy components in the catalyst, certain pretreatment conditions create the active surface phase, while reactions and post-treatments can destroy it, and the nanostructure and composition change the electronic structure and alter the selectivity and activity.     

应用基于质谱技术的电子鼻鉴别烟用辅助材料

目的是研究电子鼻系统,利用该系统,基于不同辅助材料挥发物的指纹图,开发出一种简单、快速的鉴别烟用辅助材料的方法。     

新型大环冠醚基杂化型晶体材料:分子结构和介电性质

4-氨基丁酸(4-aminobutyric acid,GABA)质子化的氨基基团与18-冠-6醚(18-crown-6)分子中六个氧原子通过N—H…O氢键相互作用,形成超分子阳离子结构,再与高碘酸根IO4-结合形成新型晶体材料[(GABAH+)(18-crown-6)(IO4-)](1)。通过元素分析、红外光谱(IR)、热重分析(TG)、单晶结构X衍射(100K和296K)和变温-介电常数测试等对所获得晶体材料进行结构分析。测试结果显示该晶体结构为单斜晶系,空间群为P21/c,室温条件下a=1.008 41(11)nm,b=2.457 3(3)nm,c=0.964 73(10)nm,α=90.00°,β=99.060(2)°,γ=90.00°,V=2.360 8(4)nm3,Z=4,Dcalc=1.574g/cm,Rint=0.036 2,WR (all data)=0.085 9。高碘酸根IO4-填充在超分子阳离子[(GABAH+)(18-crown-6)]所形成的空隙中,与4-氨基丁酸的羧酸根形成O—H…O氢键。变温-介电常数显示化合物1在280K时,出现明显的介电异常,同时存在25K的热滞现象,表明该晶体为介电新型功能材料。     

Preparation and Characterization of Novel Food Packaging Materials Based on Biodegradable PCL/Ag-Kaolinite Nanocomposites with Controlled Release Properties

Food packaging materials based on biodegradable poly(ε-caprolactone)/Ag-Kaolinite nanocomposites with controlled release properties were successfully prepared via solvent casting method. X-Ray Diffraction, UV-visible Spectroscopy and Transmission Electron Microscopy results revealed the formation of mixed intercalated-exfoliated structures with a random dispersion of spherical Ag nanoparticles. PCL/Ag-KT films have showed a significant improvement in their barrier and antibacterial properties. The potential of the silver ion release from the PCL/Ag-Kt films to an aqueous medium was measured by Atomic Absorption Spectroscopy. The results exhibited a gradual increase of the amount of silver ions released. The release’s mechanism was mainly governed by the diffusion process.     

基于快速成型技术的组织工程支架制备进展

介绍了组织工程支架的重要性和基本要求,综述了组织工程支架制备中的新技术：三雏打印技术、熔融沉积模型以及选择性激光烧结等三种快速成型技术的基本原理及应用情况,指出了各种技术的特点并对其应用前景进行了展望。     

矿用组合折迭式耐高温快速密闭结构及面料的研究

介绍耐高温复合面料的研制及加工工艺,设计了由耐高温面料、金属支架、裙边及安全窗等构成的矿用组合折迭式耐高温快速密闭结构。     

Novel Ion-Exchange Catalysts for Reactions Involving Lipophilic Reagents: Perspectives in the Reaction of Esterifications of Fatty Acids with Methanol

New catalysts for the esterification of fatty acids with methanol have been obtained from a gel type polystyrene-divinylbenzene resin (2 % cross-linked). To this purpose the starting resin was first acylated with either acetyl, butyrroyl or capryloyl groups and then sulfonated with concentrated sulfuric acid. The acylation degree ranged from 51 to 82 % and the ion exchange capacity ranged from 2.87 to 4.16 mmol/g. These catalysts were tested in the esterification of stearic acid with methanol (solution in edible oil: 5 % for the acid, 5 or 20 % for the alcohol) in a continuous glass reactor at 85 °C. At high relatively methanol concentration the catalytic activity is mainly correlated to the degree of swelling of the catalysts and the best one was the non-acylated benchmark (hence the most hydrophilic) material. At low methanol concentration the swelling is smaller and practically the same for all the catalysts. In spite of this their activity does not level down to the same value. Under these conditions the capryloyl functionalized catalysts, the most lipophilic ones, by far outperform the benchmark catalyst and in general the activity increases with the increasing lipophilic character of the catalyst. This is likely caused by the enhanced adsorption of the fatty acid close to the acidic active site, assisted by the lipophilic acyl groups.     

Two 3D Coordination Polymers with New Topology Based on Mixed Ligands: Synthesis,Structure, and Photoluminescence Properties

Employing tetracarboxylate and imidazole mixed ligands to react with different transition meat salts afford two new 3D coordination polymers, {[Zn₂(BPTC)(BBI)₂]·(H₂O)₃·DMSO}_n (1) and {[Cd₂(BPTC)(BBI)₂]·H₂O}_n (2) (H₄BPTC?=?biphenyl-3,3′,4,4′-tetracarboxylic acid, BBI?=?1,1′-(1,4-butanediyl)bis(imidazole)). Both these two coordination polymers are 4-connected network topologies. Compound 1 features a unprecedented 3-nodal (4,4,4)-connected network topology with the point symbol {6⁴·8²}, and 2 displays a (4,4)-connected binodal network bearing new topology with the point symbol of {7²·8⁴}2{7³·8³}. Additionally, thermal stability and photoluminescence properties of 1 and 2 were investigated.     

Smart Surfaces: Heterogeneous Photo-Catalysis on TiO2 Based Coatings for De-pollution Purposes in Indoor and Outdoor Environments

Topics in Catalysis - Heterogeneous photocatalysis using semiconductors, e.g. TiO2 as photocatalyst is a promising technology for the degradation of environmental pollutants. Preliminary evidence...     

Novel SO<Subscript>3</Subscript>H-Functionalized Ionic Liquids Based on Benzimidazolium Cation: Efficient and Recyclable Catalysts for One-Pot Synthesis of Biscoumarin Derivatives

Abstract  

In this article, a new group of SO₃H-functionalized ionic liquids based on benzimidazolium cation was synthesized and used as environmentally benign catalysts for the one-pot synthesis of biscoumarin derivatives. The ionic liquids showed high catalytic activities and reusabilities with good to excellent yields of the desired products. H ₀ (Hammett function) values and the minimum-energy geometries of SO₃H-functionalized ionic liquids were determined and the results revealed that the acidities and catalytic activities of ionic liquids in the synthesis of biscoumarin derivatives were related to their structures.     

基于量子点“Turn-off”模式结合化学计量学方法快速检测茶叶中多组分农残

作为一个新兴的检测模型,量子点荧光"Turn-off"模式已经成功应用于许多材料的检测,尤其在农残检测方面。研究了基于低毒性、水溶性ZnCdSe量子点"Turn-off"模式快速检测农残的新方法。通过比较百草枯、甲基硫菌灵两种常用农药对量子点荧光的猝灭程度并结合化学计量学方法,成功地实现了不拘于相同浓度下不同农药的快速分析。该方法灵敏度高、选择性好,使其在不同的茶叶背景(如红茶、英山云雾茶)中均能够对农残进行准确分析。     

A New <Emphasis Type=Italic>n</Emphasis>-Alkane Hydroisomerization Catalyst Modified with Nanosized Molybdenum Carbides and Its Catalytic Properties in Diesel Fraction Hydroisomerization. Part III: Comparison of the Catalytic Properties of Bifunctional SAPO-31 and SAPO-11 Based Catalysts

Part III of this work continues the study of the catalytic properties of new molybdenum carbide based hydroisomerization catalysts, which are resistant to sulfur compounds and allow the synthesis of waxy diesel fuels with the same quality characteristics as those of platinum-containing catalysts. The catalytic properties of such bifunctional catalysts as 7%Mo₂C/SAPO-31 (LCCH-2) and 7%Mo₂C/SAPO-11 (LCCH-2-2) in diesel fraction hydroisomerization in the temperature range of 320–400°C are compared. It is shown that LCCH-2 ensures a higher yield of the hydroisomerized diesel fraction with a lower freezing point as compared to LCCH-2-2 at temperatures above 320°C. The ratio between mono- and di-isomers in reaction products is analyzed. It is concluded that SAPO-31 based catalyst is more selective to the formation of terminal monosubstituted alkanes than SAPO-11 based catalyst. The resistance of both catalysts to deactivation with coke deposits (tests over 100 h at 320 and 360°C in hydroisomerization) is studied. It is established that LCCH-2-2 is less resistant to deactivation than LCCH-2. These findings are due to differences in acidity, the degree of uniformity in the distribution of acidic hydrogenating/dehydrogenating sites in the catalysts, and the structural type of their acidic supports.     

Organic Nanoparticles with Polypropyleneoxide Chains as Support for Metallocene Catalysts: Influence of the Concentration of PPO Chains on the Surface of Nanoparticles on the Catalyst Activity in Ethylene Polymerization

Summary In this paper the influence of the surface of organic nanoparticles used as supports in metallocene catalysed olefin polymerization is investigated. Several latex particles with different amounts of polypropylene oxide (PPO) chains on the surface were synthesized by miniemulsion polymerization and used as supports for the Me₂Si(2MeBenzInd)₂ZrCl₂ / MAO complex. These catalysts were applied in heterogeneous ethylene polymerization. It was observed that longer PPO chains on the supports coordinated more metal sites than shorter ones to give catalysts with higher activities. An increased amount of PPO chains on the supports, however, led to catalysts with lower activities. It is suggested that a higher amount of PPO chains on the support could result in a stronger network between the different nanoparticles due to the enhanced interaction of the PPO with the methylaluminoxanes so that the diffusion of the ethylene monomer to the active metal sites is hindered.