CH(A^2△和B^2∑^-)和醇类分子碰撞过程动力学研究

本文报道用四倍频YAG激光(266nm)光解CHBr3产生电子激发态CH(A,B)自由基和测量自发辐射CH(A,B→X)的时间分辨信号的方法测定了室温(290K)下CH(A,B)被醇类分子(乙醇、异丙醇、正丁醇、异戊醇和叔戊醇)猝灭的速率常数, 实验测定的CH(A)和CH(B)猝灭速率常数k~q^A和k~q^B(单位为10^-^1^0cm^3.molecule^-^1.s^-^1)值如下(误差为线性拟合的标准偏差):此外, 还从碰撞配合物模型出发, 就醇分子中OH基对猝灭速率常数的影响作了讨论。     

水溶性金属卟啉存在下硫醇氧化反应的研究

本文研究了水溶性金属卟啉存在下丁硫醇的氧化过程, 考察了金属卟啉的中心金属离子、周围基团及轴向配体与其催化活性之间的关系。发现只有钴卟啉对硫醇的氧化反应有明显的催化作用。卟啉环的周围基团对钴卟啉的催化性能有显著影响, 其活性顺序为: CoTPyP>Co(p-SO3Na)TPP>Co(p-OH)TPP>Co(p-NH2)TPP>CoTPP。研究了各种动力学因素(底物浓度、催化剂浓度、碱浓度和吡啶添加物浓度)与硫醇转化速度之间的关系并借助设想的催化循环解释了反应的动力学规律。     

二硅烯异构化反应的理论研究, 从头等水平上的动力学, 热力学分析

本文在从头算水平上计算了二硅烯HXSi-SiH2(X=H,D)异构化反应的反应物、产物及过渡态构型的能量、谐振动频率和反应活化能等,又计算了反应的热力学函数变化, 平衡常数及速率常数, 结果表明,该异构化反应是放热的, 且可自发进行, 结论与Newman的实验事实相符合, 值得注意的是, 零点能校正对该异构化反应的计算有改进。     

冠醚配合物的研究XIII:三种大环配体液膜传输碱金属离子的动力学

本文报道以2,3-苯并-11-甲基-18-冠-6,2,3-苯并-8,15-二甲基-18-冠-6和2,3-苯并-8-11,15-三甲基-18-冠-6为液膜载体,研究其对碱金属离子的传输,发现当水相金属盐浓度和膜相配体相近时,金属离子的传输为串联一级反应,求得了串级速率常数,并讨论了传输速率和配位作用的关系及载体结构的影响.     

Reaction pathways of carboxylic acids over TiO<Subscript>2</Subscript> single crystal surfaces: diketene formation from bromo-acetic acid

This work presents the first investigation of a halo-carboxylic acid (Br-CH2COOH) over the surface of an oxide single crystal (the {011}-faceted TiO₂(001) single crystal). A very rich chemistry is observed. This is broadly divided into three categories: elimination of HBr to make ketene, dimerisation of two molecules of ketene to 4-methyl-2-oxetanone and 1,3-cyclobutanedione, and further reaction of the latter to a mass spectrometer m/e 70 signal attributed to crotonaldehyde (formed by ring opening). Temperature programmed desorption (TPD) and Scanning Kinetic Spectroscopy (SKS) gave complementary results with SKS opening a simple way for investigating surface chemical reactions in UHV conditions with high surface coverage at still high temperatures. A successful modeling of SKS data was conducted providing the activation energies (E _a) for ketene desorption, with a reaction order n close to 1, for both CH₃COOH (E _a = 21.3 kcal/mol) and BrCH₂COOH (E _a = 17.2 kcal/mol). In order to further understand the surface reaction of BrCH₂COOH semi-empirical PM3 computation of its adsorption and reaction on a Ti₈O₂₉H₂₆ cluster representing the (011) TiO₂ surface was conducted and compared to that of CH₃COOH on the same cluster. Dissociative adsorptions of both the O-H and C-Br bonds are more stable than the non-dissociative adsorption modes. The di-coordinated species, TiOC(O)CH₂O_s, formed by the simultaneous dissociation of both C-Br and O-H bonds of BrCH₂COOH appears the most plausible surface intermediate for the observed carbon coupling reactions.     

STUDY ON PHOTO-INDUCED ORIENTATION OF A NOVEL PHOTO-ALIGNMENT FILM WITH SURFACE ENHANCED RAMAN SCATTERING （SERS） SPECTROSCOPY

Surface enhanced Raman scattering (SERS) spectroscopy was first utilized to study the photo-orientation behaviour of the photoreactive groups on a novel photo-alignment film surface and elucidate the generation mechanism of pretilt angle. The novel photo-alignment film was prepared by spin-coating a solution of ladderlike polysiloxane (LPS) bearing dual photoreactive group on an ITO surface and by irradiation with linear-polarized ultraviolet (LPUV) light. A Si-H terminal compound (M) containing an identical photosensitive part has been used to fabricate a model film for SERS investigation.     

乙酰水杨酸在微乳液中水解动力学研究

用紫外分光光度法研究了乙酰水杨酸在十六烷基三甲基溴化铵(CTAB)/正丁醇/25%正辛烷/H2O微乳液体系中水解动力学, 探讨了反应机理。结果表明,微乳液结构和结构转变点对乙酰水杨酸水解有影响。水解速率在油包水(W/O)微乳液结构介质中较大, 且随水含量增加而减小。而水解反应速率转变点发生在微乳液结构由W/O到B. C. 再到O/W转变点处, 认为是水解反应机理不同和界面膜极性改变造成的。     

铜(Ⅱ)催化PHA的褪色反应特性及应用

本文研究了铜(Ⅱ)催化抗坏血酸还原多卤代变色酸双偶氮胂类试剂(PHA)的褪色反应特性, 讨论了试剂结构对褪色反应动力学特性的影响, 探讨了反应机机。以三氯偶氮胂为代表, 拟定了测定痕量铜(Ⅱ)的新方法, 其检出限为3.06×10^-^1^2g/mL, 线性范围为0~28ng/10mL。用于生物材料中痕量铜(Ⅱ)的测定, 结果满意。     

2,2'-联吡啶类催化铬酸氧化异丙醇的动力学研究

2,2'-联吡啶类和它的相关化合物催化铬酸氧化异丙醇非常有效. 当2,2'-联吡啶分子的4- 和4'- 位连有甲基或甲氧基等供电基时, 催化活性加强; 当4- 和4'- 位连有吸电基氯原子时, 催化活性削弱. 2,2'-联吡啶类, Cr(Ⅵ)和异丙醇的三分子螯合物分解为产物的一步为限速步骤.