Mechanistic Study on the Ozone‐Mercury Reaction and the Effect of Water and Water Dimer Molecules

The thermodynamics and mechanism of the reaction of elemental mercury with ozone has been studied computationally. The effect of water and water dimer molecules on the reaction has also been investigated. For dry reaction, we obtained two pathways and geometry optimization, atoms in molecules analysis and vibrational frequencies of all component of reaction have been used for confirming of reaction mechanism. Thermodynamic variable of reaction has been calculated. For the reaction in the presence of the water, our studies focus on ozone‐mercury complex reaction with water and water dimer and obtained the mechanism of reactions. Comparison of wet and dry reaction shows the energy profile of reaction decreases with water molecule correspond to experimental prediction. Calculated thermodynamic variable of all reaction shows the Gibbs free energy of reaction decreases with the number of water molecule.     

Direct Dynamics Simulation of Reaction Between F2 and Ethylene

Direct dynamics within the framework of DFT was used to study the long-time puzzling mechanism of the reaction between F2 and ethylene. Three types of reactions are widely accepted : F atom elimination reaction, HF elimination reaction and the addition reaction. Several reaction mechanisms have been proposed, but only the radical mechanism can reasonably explain the initial reaction at low temperature. In this article, our calculations support the radical mechanism and the reaction mechanisms of the three reactions, and they are described in detail by trajectory simulation. The reactions in a cryogenic matrix with the reaction mechanism were also discussed.     

Synthetic and structural chemistry of groups 11 and 12 metal complexes of the zwitterionic ammonium thiolate ligands

The chemistry of metal complexes of the zwitterionic ammonium thiolates has expanded dramatically in the recent years. This review is intended to summarize the synthesis and crystal structures of groups 11 and 12 metal zwitterionic ammonium thiolate complexes. Seven methods for the synthesis of these metal complexes of the zwitterionic ammonium thiolates are outlined: proton transfer reaction, precursor reaction, ligand exchange reaction, oxidation–reduction reaction, solid-state reaction, electrochemical reaction and hydro(solvo)thermal reaction. These metal complexes of the zwitterionic ammonium thiolates are classified according to the number of metal atoms; their specific structures are briefly discussed.     

电化学反应及其腐蚀

氧化―还原反应是普遍存在的一类重要的反应。冶金、锈蚀及许多化工生产都涉及到氧化―还原反应。氧化―还原反应的本质是电子得失或偏移,如何通过化学能转变为电能,使氧化―还原反应获得或失去电子等,是化学教学中的重点和难点。文章介绍了氧化―还原反应中电化学的概念和原电池的原理,利用电化学的知识来解释一些电化学腐蚀现象。     

Photochemical Rearrangements and Fragmentations of Alkenes and Polyenes

This article presents a systematic analysis of the numerous intramolecular reactions of electronically excited alkenes categorized according to substance class and reaction type. The rearrangements and fragmentations observed in simple alkenes are usually rediscovered in non-conjugated and conjugated dienes and polyenes, where they are accompanied by reaction types such as rearrangements involving several double bonds, cyclizations, and intramolecular cycloadditions. Geometrical factors largely determine which reaction of a series of energetically feasible competing processes actually takes place. The industrial syntheses of vitamin D utilize many of the reaction types to be discussed.     

硅胶负载的亚胺环钯催化剂的制备、表征及催化性能

利用SiO2表面硅羟基与有机硅烷作用制得氨基化SiO2,再与邻甲氧基苯甲醛反应,可得到键合在SiO2微粒表面的席夫碱配体,该配体与Li2PdCl4甲醇溶液反应得到SiO2负载的亚胺环钯催化剂.采用傅里叶变换红外光谱、X射线固体粉末衍射和X射线光电子能谱等手段对催化剂进行了表征,并用于催化碘代苯(PhI)与丙烯酰胺(AM)反应生成反式-肉桂酰胺的反应中,考察了溶剂、温度、原料比、缚酸剂及其用量、催化剂用量和反应时间对催化性能的影响,从而得到适宜的反应条件,并探讨了反应机理.     

质谱技术在反应监测中的发展和应用

质谱因具有分辨率高、 灵敏度好、 响应快速以及结构鉴定能力强等特点, 近年来在反应监测研究领域应用广泛. 本文介绍了基于质谱的经典在线直接采样实时监测方案; 综合评述了常压质谱离子化技术在反应监测领域的发展和应用, 主要包括基于常压质谱的快反应监测、 微滴加速在长时间反应研究中的应用, 以及其它常压质谱在反应监测中的应用; 并对质谱在反应监测研究领域面临的挑战和发展趋势进行了总结和展望.     

离子液体介质中有机合成及不对称催化反应研究新进展

总结了近年离子液体中有机合成反应及不对称催化反应研究新进展，包括还原 反应、氧化反应、Friedel-Crafts反应、Diels-Alder反应、交叉偶联反应、加成 反应、环缩合反应、自由基反应、Witting反应、重排反应、不对称催化反应及其 它合成反应。     

The reaction between diacetyl and hydrogen peroxide: its mechanism and kinetic constants

The reaction between diacetyl and hydrogen peroxide in aqueous solution was investigated using an adiabatic reaction calorimeter. The kinetic constants are calculated using procedures based on the temperature-time behaviour of the reaction system.The mechanism of the reaction proposed fits very well with the reaction-rate equations used and the observed temperature-time data.     

反应类等键反应方法及类反应热动力学参数计算

本文提出了反应类等键反应方法,将通常用于热力学性质计算的等键反应方法推广用于类反应中反应势垒和反应焓变的计算. 对碳氢燃料低温燃烧反应机理中的一类重要反应类：?烷基自由基过氧化氢裂解生成烯烃和HO2自由基的反应势垒和反应焓变进行了计算. 通过对该类16个反应中的5个代表反应分别在不同计算水平HF、DFT、MP2、CCSD(T)的比较计算发现,采用等键反应方法可在较低从头算级别计算得到类反应较高精度的反应势垒,提高了计算的效率和精度. 本文采用反应类等键反应方法在B3LYP/6-311G(d,p)计算水平对该类16个反应进行了反应势垒和反应焓变的计算,并建立了反应势垒和反应能的线性自由能关系：delta V=71.02+0.41?delta E.     

Enantiomeric recognition and interactions

The consequences in a chemical reaction of the non-bonding interactions between molecules of one configuration on the one hand, and molecules of opposite configuration on the other hand are discussed. The reaction rates and product ratios in the reaction of a chiral compound depend upon the enantiomeric excess of the substrate. An antipodal interaction effect is observed in a phenol coupling reaction, a reductive camphor dimerization and a camphor reduction.     

Study of the reaction between boron trifluoride methanol complex and sodium methoxide

The reaction between boron trifluoride methanol complex and sodium methoxide in methanol solution was investigated using conductivity as the reaction indicator. The reaction conditions were examined and a mechanism of this reaction was proposed. Moreover, proper reaction conditions were proposed for boric acid preparation using this reaction.     

C-H bond oxidation initiated pummerer- and Knoevenagel-type reactions of benzyl sulfide and 1,3-dicarbonyl compounds

A novel Pummerer-type reaction was developed via o-chloranil-mediated C-H bond oxidation. The reaction provides a simple and efficient method to construct sulfide derivatives. A Knoevenagel-type reaction was also achieved via multiple C-H bonds activation under neutral reaction conditions.     

Three-component coupling reaction and cyclization of N-tosylimines and TMS-substituted propiolate mediated by DABCO

A new three-component coupling reaction of methyl 3-trimethylsilylpropiolate, N-tosylimine, and tosylamide mediated by DABCO was developed. This reaction was based on the consecutive alpha- and beta-activation method of propiolate involving intramolecular silyl migration previously developed by our group. On the basis of these results, a new cyclization reaction was designed to find a chromene-forming reaction utilizing salicyl N-tosylimine as a bifunctional substrate.     

硫杂蒽酮的合成和表征

为了寻求合成硫杂蒽酮的高效新方法,以2,2′-二硫代二苯甲酸和苯酚为原料,硫酸为溶剂和催化剂,考察了沸石分子筛、Al2O3和P2O5、温度、原料的物质的量之比、反应时间对反应收率的影响,确定了最佳反应条件,推测了可能的反应过程;进而以2,2′-二硫代二苯甲酸和相应的苯衍生物为原料,在H2SO4-P2O5体系中于最佳反应条件下制备了13个硫杂蒽酮类化合物,并利用柱色谱分离以及红外光谱与核磁共振谱对产物进行表征.结果表明,在反应体系中引入P2O5有利于促进反应的完成;最佳反应条件为:温度70℃、2,2′-二硫代二苯甲酸/苯衍生物物质的量之比1∶6、反应时间6h.邻苯二酚与二硫代水杨酸的反应产物——化合物11(a)和11(b)为同分异构体.     

Effect of stoichiometry and diffusion on an epoxy/amine reaction mechanism

The bulk phase kinetics of an epoxy (DGEBA) /amine (DDS) thermoset have been studied using DSC, FTIR, and ¹³C-NMR. In the absence of catalyst, the reaction was found to involve a main exothermic reaction between epoxide and amine hydrogen and a side reaction between tertiary amine formed in the main reaction and epoxide. The main reaction was exothermic while the side reaction had no discernable exotherm. Etherification did not occur to any significant extent. Since only the main reaction is exothermic, DSC was very useful for studying the main reaction kinetics. FTIR was used for determining whether epoxide and amine hydrogen were consumed at different rates as a way of following the side reaction. An IR band previously unused by other investigators was used to monitor the amine hydrogen concentration. NMR confirmed the above mechanism by identifying the formation of a quaternary ammonium ion/alkoxide ion pair as a reaction product of tertiary amine and epoxide. This mechanism has been successfully fit to a rate law valid over the entire extent of reaction. The rate constant for the epoxy/amine addition reaction was found to depend on hydroxide concentration (extent), reaction temperature, and glass transition temperature and included contributions from uncatalyzed and autocatalyzed parts. The side reaction (quaternary ammonium ion formation) formed weak bonds which did not affect the overall system T_g. Both reactions were second order. The rate constants for the main reaction first increase with increasing extent due to autocatalysis by hydroxide before decreasing due to the diffusion limit caused by gelation and vitrification. © 1995 John Wiley & Sons, Inc.     

Facile and effective copper-mediated cyclization reaction of cyclopropylideneacetic acids (or esters) and cyclopropylideneacetonitriles

The full details of the copper-mediated cyclization reaction of cyclopropylideneacetic acids (or esters) and cyclopropylidenenitriles, the synthetic application of this reaction, and the study of the reaction mechanism are reported.     

对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯共缩聚反应及醚键形成的研究

监测了对-乙酰氧基苯甲酸与聚对苯二甲酸乙二醇酯(PET)共缩聚反应过程中1HNMR图谱及特性粘度的变化,对乙酰氧基酯交换反应及乙酰脂肪酯的反应活性进行了研究。并研究了以低分子量PET或对苯二甲酸二乙二醇酯为原料时反应中醚键的形成及其进入共聚酯链的规律性。     

Study on the reaction kinetics between PBT and epoxy by a novel rheological method

In the present study, the reaction kinetics of polybutylene terephthalate (PBT) and epoxy system was studied by a novel rheological method. The reaction process was determined by rheological test and the results showed that there were three stages in the reaction between PBT and epoxy, which were reaction-controlling stage (stage I), reaction-stagnation stage (stage II) and diffusion-controlling stage (stage III). In addition, the stage I was selected to study the reaction kinetics by the rheological method. The results showed that the reaction between PBT and epoxy could be classified as a pseudo-first-order reaction due to the excessive amount of epoxy group. Furthermore, the reaction apparent activation energy of the stage I determined by the rheological method was 143 kJ/mol. To confirm these results, the reaction kinetics was also evaluated by the endgroup determination method, and the results showed that the reaction could also be classified as a pseudo-first-order reaction. Moreover, the apparent activation energy of the reaction was 116 kJ/mol, which was similar to that of the value obtained by the rheological method.