反相微乳液法制备纳米Al2O3颗粒及其形成反应机理的研究

通过聚乙二醇辛基苯基醚(曲拉通X-100)/正丁醇/环己烷/水溶液形成的体系, 采用反相微乳液法合成了Al₂O₃纳米粒子. 对前驱体进行热分析(TG-DTG-DTA), 确定了合适的煅烧温度为1150 ℃. 采用X射线衍射(XRD)、透射电镜(TEM)、紫外可见分光光度法(UV-vis)分别对产物的结构、粒度和形貌进行了表征, 考察了微乳液中水与表面活性剂的物质的量之比(ω_o)、煅烧温度和煅烧时升温速率等关键因素对产物形貌和晶相的影响, 并通过分析进一步揭示了Al₂O₃纳米粒子的形成机理. 结果表明, 控制ω_o为10、煅烧温度为1150 ℃可得到分散性好、粒径分布均匀的Al₂O₃纳米粒子, 且2 ℃/min的升温速率更有利于产物向稳定的α晶相转变.     

Sequosempervirin A, a novel spirocyclic compound from Sequoia sempervirens

A novel spirocyclic compound (4R)-4-(4-hydroxy-benzyl) spiro [4,5] dec-1-en-8-ol (sequosempervirin A) was isolated from the branches and leaves of Sequoia sempervirens. Its structure and relative stereochemistry were mainly determined by MS, 2D NMR and X-ray means, which is the first naturally occurring norlignan containing one spirocycle with C6 (cyclohexane)-C2-C3-C6 skeleton.     

聚[碳酸(亚丁酯-co-ε-己内酯)酯]的制备及其载药微球性能的研究

采用阴离子配位聚合方法, 合成了二氧化碳、1,2-环氧丁烷与ε-己内酯的三元共聚物: 聚[碳酸(亚丁酯-co-ε-己内酯)酯](PBCL). 并采用复相乳液(W/O/W)溶剂挥发法制备了包裹抗菌药物甲磺酸帕珠沙星的可降解微球. 对聚合物进行了FTIR, ¹H NMR, ¹³C NMR, DSC, TGA和WAXD等表征, 以及降解性能和载药微球特性的研究. 结果表明, PBCL热稳定性及降解性能优于聚碳酸亚丁酯(PBC). 所得PBCL微球球形规整、表面光滑. 大部分微球粒径在0.5～1 μm的范围内, 载药量和包封率分别达到38.21%和87.9%. 微球的体外释药性能研究在pH 7.4的磷酸缓冲溶液中进行, 释放21 d后, PBCL微球的累积释药量为84.74%, PBC微球的释药量仅为17.29%. 药物的体外释放行为符合Higuchi方程. PBCL载药微球具有长效缓释作用.     

添加剂对SiO电性能的影响及其机理分析

SiO_x/CoO and SiO/Li₂CO₃ composite materials were prepared by mechanical ball-milling. The structures of the obtained materials were characterized by X-ray diffraction (XRD). And scanning electron microscopes (SEM) of three samples after 20 cycles were also given. In addition， the electrochemical performances of three materials with galvanostatic charge-discharge cycling were investigated. The results show that the composite samples have larger initial reversible capacities and better cycle performance than pure SiO. Also，a schematic diagram showing the buffer effects of Li₂CO₃ addition and the mechanism of improving electrochemical performance by adding Li₂CO₃ are suggested.     

碱土金属掺杂纳米TiO2催化剂的制备与光催化活性的评价

The nanometer TiO₂ were prepared by the hydrolyze-gel method and fellowed by doping alkaline-earth metals (Mg, Ca, Sr, Ba). XRD, SEM, diffuse reflection spectra were used to investigate their characteristices. The result indicates that the average particles size of the TiO₂ is about 80 nm and keep uniformity in distributing. The product was mainly anatase in 300～400 ℃ calcinations, the einstein shift of absorption spectrum was observed after doping the alkaline-earth metals. The best mole percentages of Mg, Ca, Sr and Ba are 0.5%, 1.0%, 1.5%, 1.5% respectively. Under the same reaction conditions, it is more effective to the UV-catalyed degradation reaction that the catalysts containing Mg and Ca were calcined at 300 ℃ for 1h or containing Sr and Ba were calcined at 400 ℃ for 1 h. The photocatalystic activity is considerably depondent on pH and the concentration of the oxidant. Using the sunlight to do the degradation experimental, the result also show that the doping catalysts has higher degradation efficiency than that of pure TiO₂.     

多孔炭载聚钴酞菁修饰电极用于苯二酚的电催化及检测

以二氧化硅纳米球为模板,通过葡萄糖的水热聚合反应制备了具有三维结构的多孔炭(PC)。采用电化学聚合方法将单体钴酞菁聚合在多孔炭修饰的玻碳电极(PC/GC)表面,制备了多孔炭载聚钴酞菁的修饰电极(Co-TAPc/PC/GC)。通过循环伏安法(CV)研究了间苯二酚、邻苯二酚和对苯二酚在此修饰电极的电化学响应。结果表明,相对于裸玻碳电极、多孔炭或聚钴酞菁单独修饰的电极,该修饰电极对3种同分异构体的酚类物质均有更好的电催化活性。利用计时安培技术,该修饰电极对间苯二酚、邻苯二酚及对苯二酚分别在5.0×10-6～5.0×10-4 mol/L,6.0×10-6～2.5×10-4 mol/L和2.0×10-6～8.0×10-4 mol/L范围内具有较好的线性响应。此修饰电极具有制备简单、响应灵敏、稳定性好等优点。     

Synthesis,Structure and Norbornene Polymerization Catalyzed by o-Benzene Diimine Di-nuclear Palladium(Ⅱ) Complex

The title complex, C20H17N4Pd2Cl3·0.5CH3OH, crystallizes in the triclinic system, space group P1 with a = 9.927(6), b = 11.079(6), c = 11.233(6) ?, α = 73.970(12), β = 85.738(16), γ = 83.300(12)o, V = 1178.1(11)?3, Mr = 648.55, Z = 2, Dc = 1.520 g/cm3, μ = 1.884 mm-1, F(000) = 634, the final R = 0.0460 and wR = 0.1280. This title compound was investigated for the catalytic behavior towards norbornene(NB) vinyl addition polymerization. And the complex exhibits good catalytic activity to catalyze norbornene polymerization using MAO as a cocatalyst.     

对甲苯磺酸掺杂聚吡咯的合成、表征及其对金属镁的防腐蚀性能研究

以对甲苯磺酸为掺杂剂, 三氯化铁为氧化剂, 化学氧化吡咯制备了对甲苯磺酸掺杂聚吡咯. 考察了掺杂剂与氧化剂的用量对掺杂聚吡咯电导率的影响, 得到了高电导率聚吡咯的优化条件, 用UV, IR和SEM对其结构和形貌进行了表征. 结果表明, n(对甲苯磺酸)∶n(吡咯)∶n(三氯化铁)＝0.75∶1∶0.5时, 合成的聚吡咯的形貌规则, 电导率达42.7 S•cm^－1. 以聚吡咯为功能成分, 环氧树脂为成膜物质, 得到一种功能膜, 旋涂于金属镁表面, 采用极化曲线和开路电位考察了含有聚吡咯的膜层对金属镁的防腐蚀性能. 结果表明, 含有聚吡咯的膜层对金属镁有很好的防腐蚀性能, 腐蚀电流为0.0981 A, 腐蚀电位为－0.88 V, 在膜层与金属镁之间形成了一层钝化膜.     

Adsorption of 2,4,6-trinitrotoluene on Al(111) ultrathin film: periodic DFT calculations

The adsorption of 2,4,6-trinitrotoluene (TNT) molecule on the Al(111) ultrathin film were investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employ a supercell (4 × 4 × 2) model and three-dimensional periodic boundary conditions. The strong attractive forces between oxygen and aluminum atoms induce the N–O bond breaking of the TNT. Subsequently, the dissociated oxygen atoms and radical fragment of TNT oxidize the Al ultrathin film. The N–O bond of the o-NO₂ group is easier to rupture than that of the p-NO₂ group after the adsorption of the TNT molecule on the Al(111). Except for the breaking of the N–O bonds of the nitro group, other bonds of TNT molecule do not dissociate. The largest adsorption energy is −747.3 kJ/mol. The most of charge transfer is 3.42 e from the Al(111) to the fragment of TNT molecule. The aluminum ultrathin film is readily oxidized by the radical fragment of TNT, which is initiated by the dissociated O atoms from the nitro group.     

基于原位配体反应的锰(Ⅱ)配位聚合物的合成、结构和催化性质

采用水热方法,选用含2个氰基的醚氧桥联羧酸配体(Hdbna)和2,2′-联吡啶(2,2′-bipy)与MnCl2·4H2O反应,合成了一个二维配位聚合物[Mn(μ3-Hdpna)(2,2′-bipy)]n (1),并对其结构和催化性质进行了研究。在配合物1中,配体Hdbna在水热反应条件下,通过原位反应被转化成醚氧桥联三羧酸配体(H3dpna)。结构分析结果表明配合物1的晶体属于三斜晶系,P■空间群。配合物1具有二维层结构。研究表明,配合物1在硅腈化反应中表现出较高的催化活性。