离子液体介导CO2化学转化研究进展

The efficient utilization of carbon dioxide (CO₂) as a C1 feedstock is of great significance for green and sustainable development. Therefore, the efficient chemical conversion of CO₂ into value-added products has recently attracted a lot of research attention in recent years. The transformation of CO₂ generally requires high-energy substrates, specific catalysts, and harsh reaction conditions due to its high thermodynamic stability and kinetic inertness. Consequently, several efforts have been dedicated toward the development of high-performance catalysts and new reaction routes for CO₂ conversion over the last few decades. To date, many routes of convert CO₂ into value-added chemicals have been proposed, together with the development of heterogeneous and homogeneous catalysts. Among the advanced catalysts reported to date, ionic liquids (ILs) have been widely investigated and show great potential for the efficient, selective, and economical conversion of CO₂ into highly valuable products under mild conditions, even under ambient conditions. Some task-specific ILs have been designed with unique functional groups (e.g., —OH, —SO₃H, —NH₂, —COOH, and —C≡N), which can act as the solvent, absorbent, activating agent, catalyst, or cocatalyst to realize the transformation of CO₂ under metal-free and mild conditions. In addition, a variety of catalytic systems composed of ILs and metal catalysts have also been reported for the transformation of CO₂, in which the combination of the IL and metal catalyst is responsible for CO₂ conversion with high efficiency. In this review article, we summarize the recent advances in IL-mediated CO₂ transformation into chemicals prepared via C—O, C—N, C—S, C—H, and C—C bond forming processes. ILs that can chemically capture CO₂ with high capacity are first introduced, which can activate CO₂ via the formation of IL-based carbonates or carbamates, thus realizing the transformation of CO₂ under metal-free and mild conditions. Recent progress in IL-mediated CO₂ transformations to form carbonates and various kinds of N- and S-containing compounds (e.g., oxazolidinones, ureas, benzimidazolones, formamides, methylamines, benzothiazoles, and other chemicals) as well as CO₂ hydrogenation to give formic acid, methane, acetic acid, low-carbon alcohols, and hydrocarbons has been summarized in this review with a focus on the reaction routes, catalytic systems, and reaction mechanism. In these reactions, ILs can simultaneously activate the substrate via strong H-bonding in addition to activating CO₂, and the cooperative effects among the ionic and molecular species and metal catalysts accomplish the reactions of CO₂ with various kinds of substrates to afford a wide range of value-added chemicals. Finally, the shortcomings and perspectives of ILs are discussed. In short, IL-mediated CO₂ transformations provide green and effective routes for the synthesis of high-value chemicals, which may have great potential for a wide range of applications.     

DEHYDROGENATION AND AROMATIZATION OF METHANE IN THE ABSENCE OF OXYGEN OVER DOPED Mo/HZSM-5 CATALYSTS

研究了在Ｍｏ／ＨＺＳＭ－５催化剂上添加助剂以及不同的反应预处理温度对甲烷无氧脱氢芳构化反应的影响。实验结果表明，由于第二组分的添加，Ｍｏ／ＨＺＳＭ－５催化剂的活性和选择性都得到了较大程度的改善。预处理温度是影响催化剂反应性能的关键因素。Ｍｏ－Ｒｕ／ＨＺＳＭ－５催化剂经过８７３Ｋ空气预处理后，甲烷在９７３Ｋ的转化率约为１０％，催化剂的稳定性也得到较大程度的提高。ＴＰＳＲ实验结果表明，Ｒｕ的加入降低了芳烃生成的温度。ＴＰＯ和ＤＴＡ实验结果表明，在Ｍｏ－Ｒｕ／ＨＺＳＭ－５催化剂上可生成较多的碳物种，结合反应结果，可以认为反应过程中生成的碳物种对甲烷的无氧脱氢芳构化反应是起积极作用的     

原子结构参数的改进Xa法计算

六十年代后期,在Hartree－Fock-Slater法的基础上,提出了Xα法［1］．用于原子结构计算的Xα法与HF（Hartree－Fock）法的主要区别在于：用简单的统计平均交换势替代了HF法中计算最为困难的电子交换势,从而在保持较高理论严谨性和计算精确度的同时,大大减少了计算工作量,近年来获得了广泛的应用．我们尝试用经过适当修改的Xα方法,计算原子参数,解决分子结构中的某些问题．用原子参数解决分子问题,历来是化学和物理工作者常用的方法．本工作的意图是引入一个比HF法简单的容易在微机上实现的某种表现原子参数的计算方法,提供…     

N-（4＇-取代嘧啶-2＇-基）-取代苯氧基磺酰脲的合成及除草活性

光谱;N-（4＇-取代嘧啶-2＇-基）-取代苯氧基磺酰脲的合成及除草活性     

Application of Nafion／Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｏｎｃｈｒｏｍａｔｏｇｒａｐｈｙ (ＩＣ)ｈａｓｂｅｅｎｒｅｃｏｇｎｉｚｅｄａｓａｕｓｅｆｕｌｍｅｔｈｏｄｆｏｒｔｈｅｓｅｐａｒａｔｉｏｎｏｆｉｎｏｒｇａｎｉｃａｎｉｏｎｓａｎｄｃａｔｉｏｎｓｓｉｎｃｅｉｔｓｉｎｔｒｏｄｕｃｔｉｏｎｂｙＳｍａｌｌｅｔａｌ .ｉｎ 1975 .1ＡｓｉｇｎｉｆｉｃａｎｔｔｒｅｎｄｉｎｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆＩＣｍｅｔｈｏｄｉｓｓｅａｒｃｈｆｏｒｓｅｎｓｉｔｉｖｅａｎｄｕｎｉｖｅｒｓａｌｄｅｔｅｃｔｉｏｎｍｅｔｈｏｄｓ .Ｔｈｅｍａｉｎｄｅｔ…     

Study on the Phase Diagram of CsCl-CeCl3-HCl(11%)-H2O System and the Properties of the Compounds

The equilibrium solubility of CsCl-CeCl3-HCl(11%)-H2O qua-ternary system at 25℃ has been determined by the physicchemical analysis method ,and the phase diagram was plotted, Two new double salts 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O obtained from the complicated system were identified and characterized by XRD,TG-DTA ,DSC,UV and fluorescence spectroscopy, Studies on the fluorescence excitation and emission show that 3CsCl.CeCl3.3H2O and CsCl.CeCl3.4H2O have upconversion luminescence of infrared-visible range,and the upconversion emission intensity increases with the increase of ratio of CeCl3 in CsCl.     

消除夹带溶胀的新液膜操作法

消除夹带溶胀的新液膜操作法曹汉瑾，褚莹，何彦涛，吴子生，严忠（东北师范大学化学系长春１３００２４）关键词液膜，油／水乳液，溶胀，夹带，包裹消除液膜操作中的夹带溶胀对液膜的工业化具有重要意义，夹带溶胀分为包裹溶胀和再液化溶胀。前者是乳状液滴上浮时将水相...     

BaCe1—xRExO3—0.5x的溶胶—凝胶法合成及离子导电性

用溶胶－凝胶法合成了系列钙钛矿结构的ＢａＣｅ１－ｘＲＥｘＯ３－０．５ｘ（ＲＥ＝Ｌａ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｄｙ，Ｈｏ，Ｅｒ和Ｙ）复合氧化物，通过ＸＲＤ和热分析对样品结构及生成过程进行了研究．测定了不同温度下样品的交流阻抗谱，讨论了稀土离子掺杂对ＢａＣｅＯ３电性质的影响．溶胶－凝胶法比固相反应法合成温度降低了６００～８００℃，稀土掺杂使ＢａＣｅＯ３离子导电率提高了１０～４０倍．     

在改性非水合成的丝光沸石上邻二甲苯异构化

1985年Bibby首次在非水体系中合成了纯硅方钠石,由此开创了一条合成分子筛的新途径。徐文旸等首次在Na_2O-SiO_2-Al_2O_3一有机胺非水体系中合成了丝光沸石(简称非水丝光沸石,用NAM表示)。晶化过程中液相无硅铝酸根离子,固相硅铝比始终保持不变,是典型的固相转化过程。利用非水体系这一特点,可以定向地合成出催化反应所需硅铝比的沸石。与水热体系相比,非水体系合成的丝光沸石在邻二甲苯异构化催化性能上要优于前者。