高活性锆掺杂钴催化剂的制备及其催化甲烷燃烧性能研究

由水热法制备了掺杂锆摩尔百分比为0，10，20，30．40，50％的钴催化剂，该系列催化剂对甲烷的低温催化燃烧显示出高活性．其中，10％Zr掺杂的催化剂活性最好，可在370℃使甲烷转化率达100％．XRD分析表明，该法制得的催化剂中的活性四氧化三钴物种是由一种晶态的碳酸钴前体分解而成，Co3O4为粒径在20～40nm之问的纳米粒子．用热重分析(TG)研究了碳酸钴前体的热分解行为．     

Phase Analysis of the Binary System of Cryolite (Na3AlF6) and Sodium Metasilicate (Na2SiO3)

The phase analysis of cryolite (Na₃AlF₆) and sodium metasilicate (Na₂SiO₃) was performed by thermal analysis. The eutectic system with a region of two immiscible substances at a concentration of Na₂SiO₃ between 42.8 and 46.3 mol‐% was identified and the eutectic temperature determined to (886±2) °C. Based on the results of mass‐loss measurements, it was assumed that the introduced Na₂SiO₃ reacts with Na₃AlF₆ due to the formation of some nonvolatile stable compounds. The stable reaction products were identified by X‐ray diffraction analysis and IR spectroscopy of the spontaneously cooled samples, which established the formation of NaF and stable amorphous aluminosilicate compounds.     

氯化钠在球形纳米氧化铈形成过程中的作用

以水合碳酸铈为原料, 以氯化钠作为助磨剂和阻聚剂, 采用机械活化法制备了球形纳米氧化铈, 用XRD法研究了水合碳酸铈与氯化钠质量比、球磨时间、煅烧温度对CeO2粉体晶粒度的影响, 用TEM对最终产物粒子进行形貌观察. 结果表明: 在碳酸铈的球磨过程及其随后的煅烧过程中, 氯化钠的存在起到了很好的助磨和阻聚作用, 所得CeO2为类球形粒子, 分散性较好, 晶粒度约为30～50 nm.     

Vapor pressure,speciation, and chemical activities in highly concentrated sodium borate solutions at 277 and 317°C

The system H₂O-B₂O₃-Na₂O has been studied experimentally at 277 and 317°C. The activities of water and boric acid have been determined at mole ratios Na/B from 0 to 1.5, and total dissolved solids 3 to 80 weight percent. The activity of boric acid has been fitted to within experimental error using a speciation model with eight complex species. This model is consistent with the model previously published by Mesmer et al. The electrolyte properties of the liquid are modeled using the Pitzer-Simonson model of very concentrated electrolyte solutions. The calculated values of water activity agree with experiment, and the activity of NaOH and pOH have also been calculated. The potassium borate system also was briefly studied at 317°C, and is adequately described by a model with five complex species. The potassium borate liquid is more alkaline at K/B= 1 than a sodium borate liquid at the same mole ratio, but pOH in the two systems is the same at lower mole ratios.     

典型无机含氧酸自由基的特性

碳酸自由基、硝酸自由基、磷酸自由基和硫酸自由基是化学反应的重要中间体，都具有氧化性，对污染物在自然和人为环境中的迁移转化会产生重要的影响.文中较为详细地介绍这几种自由基的电极电位、产生方式、检测方法及与有机物的反应方式.总结四种自由基的特性及与有机物的反应方式可发现，四种自由基和羟自由基电极电位不同，导致它们和有机物反应速率的不同；碳酸自由基并不是羟自由基去除剂，对于一些容易被氧化的化合物，碳酸自由基氧化效果比羟自由基好；四种自由基均可由羟自由基转化而来，并且这四种自由基和羟自由基与有机物反应方式基本一致，都通过电子转移、夺氢和加成的方式进行.可以预测四种自由基和羟自由基降解有机物的机理将非常相似，今后应研究四种自由基与羟自由基相互转化的规律，以及与代表性有机物的反应机理.     

丙醇-氯化钠双水相体系萃取分离铂、钯、铑、金中的铱及其吸收光谱分析研究

提出了一种丙醇－氯化钠双水相体系萃取铱的分离－吸收光谱分析方法，在HCl介质中基于铱生成三氯亚锡酸络阴离子动力学速率与铂、钯、铑、金差异使铱与铂、钯、铑、金分离，其后在KI介质中萃取铱使其与贱金属基体分离，研究了在丙醇萃取相中铱的吸收光谱分析，并应用于实际样品中铱的测定。     

Solid-phase microextraction–capillary gas chromatography combined with microwave-induced plasma atomic-emission spectrometry for selenite determination

The use of solid-phase microextraction (SPME) with gas chromatography coupled to microwave-induced plasma atomic-emission detection (GC–MIP-AED) is described for selenite [Se(IV)] speciation. Aqueous standards were derivatised with sodium tetraethyl- or tetrapropylborate and extracted by SPME. Headspace extraction of the ethyl and propyl derivatives was studied. Relevant experimental conditions were optimised, including conditions for derivatisation and extraction and those of gas chromatographic analysis. The limits of detection achieved for headspace sampling of derivatised Se(IV) were in the low ng mL^–1 range for both ethylation and propylation. When the method was applied to analysis of selenite in selenised yeast reference material results were in good agreement with the indicated values.     

NaAg3S2, ein Thioargentat mit dem Clusteranion [Ag6S4]2−

NaAg₃S₂, a Thioargentate Containing the Anionic Cluster [Ag₆S₄]^2? . Dark-red octahedrally shaped crystals of NaAg₃S₂ could be obtained by the reaction of NaAg(CN)₂ and NaCN in a stream of hydrogen sulfide at 630 K. NaAg₃S₂ crystallizes cubic, a=12.358(1) Å, space group Fd3 m, Z=16. The structure was determined from four-circle diffractometer data. NaAg₃S₂ contains the anionic cluster [Ag₆S₄]^2?. The structure can be traced back to the spinel structure typ. An extended Hückel calculation for the cluster anion, which is considered to be isolated, shows weak bonding silver-silver interactions. NaAg₃S₂ is diamagnetic at room temperature.     

Activation of Carbon Dioxide and Synthesis of Propylene Carbonate

Cycloaddition of carbon dioxdie and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine(TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine.Comparing different catalysts of diverse metals,(t-Bu)4PcMg is more active than (t-Bu)PcFe ,But(t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction.Moreover,the yield will increase as the temperature increases.