不同干燥过程对超细TiO2粉体性质的影响

考察了采用不同干燥工艺制备的TiO2粉体在粒子形貌、颗粒大小与分布、晶相组成以及比表面积和孔结构等织构和结构性质方面的差异。结果表明，利用常规的干燥方法，由水凝胶脱水所得的颗粒，颗粒间严重团聚，颗粒粒径大且分布不均匀，比表面积和孔体积最小；由醇凝胶直接脱水，则可以显著提高粉体的织构性能．而采用超临界流体干燥法则可以进一步提高粉体的性能，比表面积由水凝胶的4．88m2·g－1增大到113．8m2·g－1，提高了近30倍；孔体积由0．027cm3·g－1增大到0．41cm3·g-1．大约提高了15倍；而且其能够有效地防止粒子间的团聚，较好地保持了湿凝胶的网络结构，使颗粒尺寸降低且分布均匀，可重复性好．     

超临界流体干燥法合成超微二氧化锡

采用溶胶－凝胶法制备出胶体，利用超临界流体干燥技术合成出高比表面，纳米级ＳｎＯ＿２超细粉体，用ｘ－射线衍射，透射电镜和比表面及孔分布测试等分析了ＳｎＯ＿２的结构，形貌及比表面。     

担载多孔Al2O3

研究了溶胶－凝胶法在多孔陶瓷载体上制备多孔Ａｌ２Ｏ３膜的工艺条件，发现在孔直径为１．１和１．６μｍ的多孔陶瓷载体上必须经过多次重复浸渍－干燥－焙烧过程，才能制备出担载均匀的多孔Ａｌ２Ｏ３膜，对溶胶和多孔陶瓷载体进行适当的化学改性后，能够减少浸渍－干燥－焙烧过程重复的次数，对Ａｌ２Ｏ３膜的孔径大小和透气性能进行了表征。     

合成低碳醇超细Mo-Co-K催化剂的制备及其表征

采用类凝胶法和超临界流体干燥技术制备超细Ｍｏ－Ｃｏ－Ｋ催化剂。通过ＢＥＴ,ＴＥＭ,ＸＲＤ和ＴＰＲ等表征手段比较分析了不同制备参数尤其是Ｃｏ／Ｍｏ比对超细Ｍｏ－Ｃｏ－Ｋ催化剂性能的影响。结果表明,制得的催化剂为大比表面积、小粒径、大孔超细粒子。     

担载多孔Al_2O_3膜的制备

研究了溶胶－凝胶法在多孔陶瓷载体上制备多孔Ａｌ２Ｏ３膜的工艺条件。发现在孔直径为１．１和１．６ｕｍ的多孔陶瓷载体上必须经过多次重复浸渍干燥－焙烧过程，才能制备出担载均匀的多孔Ａｌ２Ｏ３膜。对溶胶和多孔陶瓷载体进行适当的化学改性后，能够减少浸渍－干燥－焙烧过程重复的次数。对Ａｌ２Ｏ３膜的孔径大小和透气性能进行了表征。     

不同制法镁铝尖晶石在环己酮双聚中的应用

用共沉淀法，溶胶－凝胶法，超临界干燥技术和脲燃烧法制备了一系列镁铝尖晶石，并将其用于环己酮双聚合成环己烯环己酮（ＣＨＣＨ）的反应中。借助于ＴＥＭ、ＸＲＤ、ＢＥＴ和ＣＯ＿２－ＴＰＤ等手段考察了不同制备方法对催化剂性质及性能的影响。     

Fe／ZrO_2气凝胶超细粒子催化剂的制备、表征及F－T反应性能的研究

用超临界流体干燥法制备出大孔高比表面高分散态Ｆｅ／ＺｒＯ_２气凝胶超细粒子催化剂，研究了在其制备过程中织构性质、颗粒大小、体相和表面结构的变化，并与普通浸渍法制备的Ｆｅ／ＺｒＯ_２催化剂作了对比。对几种Ｆｅ／ＺｒＯ_２催化剂的Ｆ－Ｔ反应性能考察表明，Ｆｅ／ＺｅＯ_２气凝胶超细催化剂显示出高的反应活性；随载体ＺｒＯ_２颗粒尺寸减小，活性组分铁的分散度变大，其颗粒尺寸变小，催化剂比表面积增大，反应活性增大，甲烷和低碳烃生成量增加，重质组分减少，认为产物烃分布主要受催化剂活性相颗粒尺寸效应制约。     

超细镍基催化剂上CH4-CO2重整反应的性能 Ⅱ.制备方法对催化性能及积碳性能的影响

采用溶胶－凝胶法和超临界干燥（ＳＣＤ）技术制备了超细二元ＮｉＯ－Ａｌ２Ｏ３和三元ＮｉＯ－Ｌａ２Ｏ３－Ａｌ２Ｏ３催化剂,并以浸渍超细氧化铝载体和普通氧化铝载体制得的二元和三元催化剂为对比,考察了不同制备方法对催化剂上ＣＨ４－ＣＯ２重整反应性能的影响。结果表明,超细催化剂表现出很高的高温催化活性、选择性和显著的抗积碳能力,即使不含助剂的超细二元催化剂也明显优于含镧助剂的负载三元催化剂,而含镧的超细三元     

微乳法制备纳米级WO3粉体

以最佳重量比６：４的∈ＣＨ２－ＣＨＯＨ）ｎ和ＣＨ３Ｃ１０Ｈ２２ＣＯＣＨ（ＯＨ）ＣＨ（ＯＨ）ＮＨ２作为混合型乳化剂，在二甲苯／水体系中首次制备了纳米级三氧化钨粉体，确定了最佳反应条件。在不同温度下处理得到的纳米级粉体为分散的规则球形粒子（最小尺寸为１５ｎｍ）。用透射电镜和Ｘ－Ｒａｙ衍射对各种温度处理得到的ＷＯ３粉体进行了分析。所制备的ＷＯ３纯度为９９．９６％。     

超临界流体干燥法制备纳米TiO2－ZnO复合催化剂及其对苯酚降解的光催化性能

 以TiCl4和Zn（NO3）2·6H2O为原料，采用溶胶－凝胶法结合超临界流体干燥法制备了纳米级TiO2－ZnO（7～10nm）复合催化剂，并用XRD和TEM等手段进行了表征．以苯酚光催化降解为模型反应对所制备催化剂的催化性能进行了评价．结果表明，与单组分TiO2及普通干燥法制备的TiO2－ZnO催化剂相比较，纳米TiO2－ZnO复合粒子的光催化活性有较大提高．用超临界干燥法制备的催化剂具有粒径小、分布窄、比表面积大、分散性好和光催化活性高等特点．采用超临界流体干燥法可直接制得纳米TiO2（锐钛矿型）－ZnO（非晶态）复合催化剂，可实现干燥、晶化一步完成．复合催化剂中ZnO的最佳掺入量为x（ZnO）＝0．8％．超临界流体干燥法是制备纳米材料的一种新技术，具有产物容易收集和溶剂可回收利用等优点．     

电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量

建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定镀锡钢板中的镀锡量的方法。为避免复杂基体、溶样时间对测试结果产生干扰,采用标准加入法进行定量分析。通过实验,确定了溶样用盐酸的浓度、ICP仪器参数以及待测元素的分析线。考察了标准曲线的相关性、精密度和准确度等分析指标。结果表明,标准曲线成线性关系(R=0.998 8),检测结果的相对标准偏差仅为1.3%,与现有的国家标准分析方法——碘酸钾滴定法和X射线荧光光谱法进行对比实验,测量结果基本一致。     

N → Sn coordination in the complexes of tin halides with pyridine: A comparison between Sn(II) and Sn(IV)

The experimentally well‐known complexation of tin(II) and tin(IV) halides with pyridine (py) leads to structures showing N → Sn coordination. In the present work, the complexes SnX_n·mpy (where X = F, Cl, Br, I; n = 2, 4; m = 1, 2) possessing this kind of coordination were studied using a computational quantum chemical approach. Various aspects in the theoretical picture of these complexes were examined to find similarities and differences in their N → Sn coordination. The aspects included, among others, the physical nature of intermolecular interactions, and their role in establishing the structure and energetic stabilization of the complexes. In this context, the effect of tin valency was inspected in great detail. As proven by several theoretical methods, a largely ionic character with a certain covalent component can be attributed to the studied N → Sn coordination, irrespective of tin valency. All complexes are destabilized by py‐py and three‐body interactions, but the Sn(II) complexes experience it to a greater extent. Marked differences are observed in the structural behavior of N → Sn and SnX_n during complex formation. This affects the energetics of complexation and, in consequence, the penta‐coordinated Sn(IV) center shows a higher propensity to expand its coordination number, compared with the tri‐coordinated Sn(II) center. The present study supplements the experimental characterization of SnX_n·mpy and, in general, it sheds light on the coordination of heteroaromatic nitrogen to tin. The survey of the Cambridge Structural Database revealed that such coordination occurred in a number of crystal structures.     

Optically active pentacyclic binuclear diorganotin compounds

Three optically active binuclear diorganotin compounds (2-4) were prepared from an optically active oxalamide: (1S,2R)-(−)-[N-(2-hydroxy-1-methyl-2-phenyl-ethyl)-N′-(2-hydroxy-phenyl)-oxalamide (1). The new compounds [1-(2′,2′-diorganyl-1′-oxa-3′-aza-2′-stanna-indan-3′-yl)-2-(2″,2″-diorganyl-4″-methyl-5″-phenyl[1,3,2]-oxazastannolidin-3″-yl)-ethane-1,2-dione {organyl = methyl (2), n-butyl (3) or phenyl (4)} were characterized by IR, elemental analysis and mass spectrometry. Compounds 3 and 4 were submitted to a detailed NMR study in order to assign their resonances (¹H and ¹³C) and specially the two different ¹¹⁹Sn signals for each compound. The X-ray diffraction analysis of compound 4 showed a planar pentacyclic framework with two penta-coordinated tin atoms with a distorted tbp geometry and 12 intramolecular hydrogen bonds.     

Alkylchlorotins grafted to cross-linked polystyrene beads by a -(CH2)n- spacer (n=4, 6, 11): selective, clean and recyclable catalysts for transesterification reactions

Insoluble polystyrene grafted compounds of the type (P-H)(1-t){P-(CH2)n SnBu(p)Cl(3-p)}(t), (P-H)(1-t){P-(CH2)n SnBuO}(t) and (P-H)(1-t)[{P-(CH2)n SnBuCl}2O](t/2), in which (P-H) is a cross-linked polystyrene; n=4, 6, and 11; p=0 and 1; and t the degree of functionalisation, were synthesised from Amberlite XE-305, a polystyrene cross-linked with divinylbenzene. The compounds were characterised by using elemental analysis, and IR, Raman, solid-state 117Sn NMR, and 1H and 119Sn high-resolution MAS NMR spectroscopy. The influence of the spacer length and the tin functionality on the catalytic activity of these compounds, as well as their recycling ability, was assessed in the transesterification reaction of ethyl acetate with various alcohols. These studies showed significant differences in the activity of the catalysts interpreted in terms of changes in the mobility of the catalytic centres. Some of the supported catalysts could be recycled at least seven times without noticeable loss of activity. The residual tin content in the reaction products was found to be as low as 3 ppm.     

A Multi‐Wall Sn/SnO2@Carbon Hollow Nanofiber Anode Material for High‐Rate and Long‐Life Lithium‐Ion Batteries

Multi‐wall Sn/SnO₂@carbon hollow nanofibers evolved from SnO₂ nanofibers are designed and programable synthesized by electrospinning, polypyrrole coating, and annealing reduction. The synthesized hollow nanofibers have a special wire‐in‐double‐wall‐tube structure with larger specific surface area and abundant inner spaces, which can provide effective contacting area of electrolyte with electrode materials and more active sites for redox reaction. It shows excellent cycling stability by virtue of effectively alleviating pulverization of tin‐based electrode materials caused by volume expansion. Even after 2000 cycles, the wire‐in‐double‐wall‐tube Sn/SnO₂@carbon nanofibers exhibit a high specific capacity of 986.3 mAh g^?1 (1 A g^?1) and still maintains 508.2 mAh g^?1 at high current density of 5 A g^?1. This outstanding electrochemical performance suggests the multi‐wall Sn/SnO₂@ carbon hollow nanofibers are great promising for high performance energy storage systems.     

Studies on the reaction of organotin phenoxides with ethyl propiolate catalysed by triethylamine and tin(IV) chloride

Different tributyltin phenoxides react at room temperature with ethyl propiolate in benzene, in the presence of tin(IV) chloride, triethylamine and their mixture to give the derivatives of 3‐phenoxyacrylic acid ethyl ester. Exceptionally, 3‐(2‐hydroxyphenyl)acrylic acid ethyl ester and 3‐(2‐hydroxy‐5‐methylphenyl)acrylic acid ethyl ester have been obtained from the reaction of tributylphenoxytin and tributyl(p‐tolyloxy)tin, respectively catalysed by SnCl₄, and they have been easily hydrolysed to coumarin and 6‐methylcoumarin. Copyright © 2007 John Wiley & Sons, Ltd.     

Tin dithiocarbamates: applications and structures

The uses and potential utility of tin/organotin dithiocarbamate, ^?S₂CNR′₂, compounds are reviewed. Various derivatives exhibit exciting potential as anti‐cancer agents, anti‐microbial agents and insecticides, e.g. against mosquito larvae. Tin dithiocarbamates have also proven useful as precursors for tin sulfide nanoparticles. There is a wealth of structural data available for such compounds and with the exception of the diorganotin bis(dithiocarbamate) compounds, R₂Sn(S₂CNR′₂)₂, compounds for which different structural motifs are evident, there is a certain degree of homogeneity in the molecular structures for each class of compound unless there are additional coordination sites on the R and/or R′ groups. Owing to the strong coordination potential of the dithiocarbamate ligand for tin, supramolecular aggregates involving secondary Sn…S interactions are the exception rather than the norm. Copyright © 2008 John Wiley & Sons, Ltd.     

Reversible Storage of Lithium in a Rambutan‐Like Tin–Carbon Electrode

Fruity electrodes : A simple bottom‐up self‐assembly method was used to fabricate rambutan‐like tin–carbon (Sn@C) nanoarchitecture (see scheme, green Sn) to improve the reversible storage of lithium in tin. The mechanism of the growth of the pear‐like hairs is explored.