聚苯乙烯磺酸掺杂聚苯胺的合成

以苯胺（An）为单体，过硫酸铵（APS）为氧化剂，在聚苯乙烯磺酸（PSSA）的水溶液中，合成了可完全溶于水的PSSA掺杂PAn。研究了An浓度，PSSA浓度，APS浓度，APS的滴加时间，反应时间及温度对An聚合反应及其产物的水溶性，导电性及特性粘度[η]的影响。结果表明：在比较宽的实验条件下，都可以合成出具有良好导电性的可溶于水的PSSA掺杂PAn；其中当An：PSSA:APS的摩尔比为1．7：2．5：1，APS溶液的滴加时间为3h，反应时间为1h，反应温度为14℃时，得到的掺杂PAn导电率最高达0．156S／cm。     

Theoretical Study on the Isomerization Mechanism of Enol Ester from 2-Acyl-1, 3-cyclohexanediones

The present paper employed density function theory to investigate two reaction pathways for isomerization of enol ester proposed by Yang(path a) and the present authors(path a), respectively. The base catalytic effects of solvent triethylamine on these two reactions were also evaluated. It is demonstrated that path B is more preferable than path a due to low barrier height for the rate-determining step.     

锂离子电池高比容量FeSn2-C复合负极材料的合成与性能

Sn基合金负极材料具有高达990 mAh·g^-1的理论比容量,但其也存在因脱嵌锂过程发生巨大的体积变化而导致循环性能较差的问题. 本文以Sn、Fe、石墨为原料利用简易的高能球磨法成功制备了具有核壳结构的FeSn₂-C复合物,系统研究了球磨时间、FeSn₂相含量对材料物相结构及电化学性能的影响,并分析了电极的失效机理. 研究表明,球磨时间的增加有利于FeSn₂金属间化合物相的形成及材料颗粒的细化,进而有利于材料比容量的增加及循环性能的提升;FeSn₂相含量的增加能够提高FeSn₂-C材料的比容量,但会降低FeSn₂-C电极的循环稳定性. 经工艺优化及组分调节,球磨24 h合成的Sn₂₀Fe₁₀C₇₀材料具有最优的电化学性能,材料的比容量在540 mAh·g^-1左右,并能稳定循环100次,是一种非常有发展前途的锂离子电池高比容量负极材料.     

One step isolation and purification of liquiritigenin and isoliquiritigenin from Glycyrrhiza uralensis Risch. using high-speed counter-current chromatography

High-speed counter-current chromatography (HSCCC) technique in semi-preparative scale has been successfully applied to the separation of bioactive flavonoid compounds, liquiritigenin and isoliquiritigenin in one step from the crude extract of Glycyrrhiza uralensis Risch. The HSCCC was performed using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-acetonitrile-water (2:2:1:0.6:2, v/v). Yields of liquiritigenin (98.9% purity) and isoliquiritigenin (98.3% purity) obtained were 0.52% and 0.32%. Chemical structures of the purified liquiritigenin and isoliquiritigenin were identified by electrospray ionization-MS (ESI-MS) and NMR analysis.     

Cyclic Voltammograms of Ferrocene on Multi‐Walled Carbon Nanotubes (MWCNTs)‐Modified Edge Plane Pyrolytic Graphite (EPPG) Electrode in Room Temperature Ionic Liquids (RTILs) of 1‐Ethyl‐3‐Methylimidazolium Tetrafluoroborate (EMIBF4)

In this work, the electrochemical behavior of ferrocene (Fc) was investigated by cyclic voltammetry (CV) in room temperature ionic liquids (RTILs) of 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIBF₄) on glass carbon (GC), edge plane pyrolytic graphite (EPPG) and multi‐walled carbon nanotube (MWCNTs)‐modified EPPG electrodes, respectively. The results demonstrated that on GC electrode, pairs of well‐defined reversible peaks were observed, while for the electrode of EPPG, the peak potential separation (ΔE_p) is obviously larger than the theoretical value of 59 mV, hinting that the electrode of EPPG is distinguished from the commonly used electrode, consistent with the previous proposition that EPPG has many “defects”. To obtain an improved electrochemical response, multi‐walled carbon nanotubes (MWCNTs) were modified on the electrode of EPPG; the increased peak current and promoted peak potential separation not only proved the existence of “defects” in MWCNTs, but also supported that “creating active points” on an electrode is the main contribution of MWCNTs. Initiating the electrochemical research of Fc on the MWCNTs‐modified EPPG electrode in RTILs and verifying the presence of “defects” on both EPPG and MWCNTs using cyclic voltammograms (CVs) of Fc obtained in RTILs of EMIBF₄, is the main contribution of this preliminary work.     

高效液相色谱-电感耦合等离子体质谱法同时测定化妆品中5种含溴防腐剂

建立了同时测定化妆品中苯扎溴铵、2-溴-2-硝基-1,3-丙二醇、5-溴-5-硝基-1,3-二■烷、甲基二溴戊二腈、溴氯芬5种含溴防腐剂的高效液相色谱-电感耦合等离子体质谱法(HPLC-ICP-MS)。样品经含0.1%甲酸的甲醇溶液超声提取后,采用Agilent Eclipse-C_(18)(150 mm×4.6 mm,5μm)色谱柱分离,以0.1%甲酸-甲醇为流动相进行梯度洗脱,ICP-MS测定组分中的~(79)Br,以保留时间定性,外标法定量。5种含溴防腐剂均在0.5～100 mg/L范围内线性关系良好(r0.999),检出限为1.5～3.0μg/g,不同基质化妆品中的回收率为91.2%～108%,相对标准偏差(n=6)为1.3%～4.2%。该方法快速、准确、灵敏、专属性强,适用于化妆品中5种含溴防腐剂的定性定量分析。     

席夫碱自组装单分子膜的电化学行为

利用自组装技术将席夫碱硫醇衍生物在金表面形成自组装单分子膜,并初步研究了此自组装单分子膜的电化学行为,发现该席夫碱分子在0.1 mol•L－1的KCl溶液中具有电化学不可逆氧化还原行为，且随着自组装时间的增加表观电极反应速率常数值显著减小,最后减小为0,并对此进行了解释.     

天然水体底质中腐植酸的光谱表征

分别用紫外-可见光谱、傅立叶变换红外光谱(FTIR)、三维荧光光谱和荧光等高线谱对提取的腐植酸和商品腐植酸进行了表征，并将分析结果与Aldrich和上海试剂二厂生产的腐植酸进行了比较。结果表明：3种底质腐植酸之间以及同商品腐植酸的紫外-可见光谱、傅立叶变换红外光谱(FTIR)相似，含有相同类型的官能团。对不同腐植酸的三维荧光光谱和荧光等高线谱的分析表明其在结构上存在一定的差异；腐植酸有较明显的荧光光谱特性，可以尝试使用三维荧光光谱技术来揭示其在结构上的差异。     

基于5-芳基乙内酰脲类化合物的CoMFA和HQSAR研究

用CoMFA和HQSAR两种QSAR方法研究了50个乙内酰脲类分子的定量构效关系.本研究从构象搜索所得的低能结构出发构建化合物分子的构象, 建立CoMFA模型,并进行了全空间搜索. HQSAR本质上是一种二维的QSAR方法,与CoMFA方法相比,该方法在数据处理方面,比CoMFA方法快捷,并且可重复性好.两种方法均得到了较好分析结果, CoMFA的交叉验证相关系数q2 值为0.815, HQSAR的q2值为0.893.这些方程有力地说明了该类分子在(R,R)-N-3,5-dinitrobenzoyl-1,2-diamine型手性固定相上拆分过程中的影响因素,对今后类似拆分的实验研究提供了理论支持.     

Study on the Tautomer Interconversion of 3-Oxo Pentanoate During Gas Chromatography

Enol and keto tautomers of methyl 3-oxo pentanoate could be separated on a HP-5 capillary column. The chromatographic peaks were identified by examining characteristic mass ions arose from the corresponding enol and keto molecular ions. The study showed that the area percentage of enol tautomer is a function of temperature of the column. Treating the column as a reactor, the energy of activation for the on-column tautomerization could be extracted (35.1 kJ mol⁻¹) by monitoring the loss of the enol tautomer, because the reaction is found to obey pseudo first-order kinetics. The enthalpy and the entropy changes (ΔH = −3.98 kJ mol⁻¹, ΔS = −7.89 J K⁻¹mol⁻¹) for the enol-to-keto reaction in the stationary phase were also obtained.