离子液体中棒状ZnO粉体的制备及光催化性能

制备了离子液体1-乙基-3-甲基咪唑溴盐([emin]Br),以该离子液体为模板剂,采用水热法制备了亚微米级棒状ZnO粉体。经扫描电子显微镜(SEM)、X射线衍射(XRD)、傅立叶转换红外光谱(FT-IR)等对样品进行了表征和分析。结果表明,该方法制备出具有六方纤锌矿结构的棒状亚微米级ZnO粉体,棒长为2~3μm,直径为500~600 nm;以高压汞灯为光源,以ZnO粉体为光催化剂,对有机染料罗丹明B进行了光降解实验,光降解90 min后,其去除率达到93.3%。     

1-乙基-3-甲基咪唑四氟硼酸盐离子液体结构性质的模拟计算

离子液体以其独特的性质广受关注,被称为"绿色设计者溶剂",人们对其潜在的应用价值做了大量的研究.实验采用HyperChem软件构建了1-乙基-3-甲基咪唑四氟硼酸盐([EMIM][BF4])离子液体分子结构的3D模型,并用PM3法进行预优化,然后应用Gaussian 03w程序分别在RHF/6.31G(d)和BLYP/6-31G(d)计算水平上进行量子化学计算,并经振动频率和强度分析得到理论红外谱图.结果表明,[EMIM][BF4]离子液体的阴阳离子存在着氢键等弱相互作用.     

以离子液体为溶剂制备纤维素微球

将天然纤维素溶于离子液体中,制成纤维素/离子液体溶液,并以纤维素/离子液体溶液为原料采用悬浮聚合法制备了纤维素微球.讨论了纤维素种类和质量分数、纤维素/离子液体溶液与导热油体积比、搅拌速度和制备温度对纤维素微球粒径分布的影响.结果表明,质量分数为2％的棉纤维素/离子液体溶液,以导热油为分散相,V(纤维素/离子液体溶液)...     

Organo-zincate molten salts as immobilising agents for organometallic catalysis

The combination of 1-n-butyl-3-methylimidazolium chloride with ZnCl₂ affords ionic mixtures with different melting point temperatures depending on the zinc molar fraction. RuCl₂(PPh₃)₃ immobilised in the low melting mixture (60°C) promotes the 1-hexene hydrogenation (turnover frequencies up to 44 min^–1) and the recovered solid catalyst phase can be reused several times.     

Ionic conductivity enhancement of the plasticized PMMA/LiClO4 polymer nanocomposite electrolyte containing clay

This work has demonstrated that the addition of an optimum content of dimethyldioctadecylammonium chloride (DDAC)-modified montmorillonite clay (Dclay) enhances the ionic conductivity of the plasticized poly(methyl methacrylate)-based electrolyte by nearly 40 times higher than the plain system. Specific interactions among silicate layer, carbonyl group (CO) and lithium cation have been investigated using Fourier-transform infrared (FTIR), solid-state NMR, alternating current impedance. The FTIR characterization confirms that both of the relative fractions of ‘complexed’ CO sites and ‘free’ anions increase with the increase of the Dclay content, indicating that strong interaction exists between the CO group and the lithium salt. In addition, the solid-state NMR demonstrates that the interaction between the PMMA and the clay mineral is insignificant. The addition of clay mineral promotes the dissociation of the lithium salt and thus, the specific interaction can be enhanced between the CO and the free lithium cation. However, the balanced attractive forces among silicate layers, CO groups, lithium cations and anions is critical to result in the higher ionic conductivity.     

Polymer electrolytes from PEO and novel quaternary ammonium iodides for dye-sensitized solar cells

Polymer electrolytes were prepared by blending high molecular weight poly(ethylene oxide) (PEO) and a series of novel quaternary ammonium iodides, the polysiloxanes with oligo(oxyethylene) side chains and quaternary ammonium groups. X-ray diffraction (XRD) measurements ensured relatively low crystallinity when the quaternary ammonium iodides were incorporated into the PEO host. The ionic conductivity of these complexes was improved with the addition of plasticizers. The improvement in the ionic conductivity was determined by the polarity, viscosity and amounts of plasticizers. A plasticized electrolyte containing the novel quaternary ammonium iodide was successfully used in fabricating a quasi-solid-state dye-sensitized solar cell for the first time. The fill factor and energy conversion efficiency of the cell were calculated to be 0.68 and 1.39%, respectively.     

Gel polymer electrolyte based on poly(acrylonitrile-co-styrene) and a novel organic iodide salt for quasi-solid state dye-sensitized solar cell

A gel polymer electrolyte based on poly(acrylonitrile-co-styrene) as polymer matrix and N-methyl pyridine iodide salt as I⁻ source was prepared. Controlling the concentration of polymer matrix of poly(acrylonitrile-co-styrene) at 17.5 wt.%, mixing the binary organic solvents mixture ethylene carbonate and propylene carbonate with 6:4 (w/w), and the concentration of N-methyl pyridine iodide and iodine with 0.5 and 0.05 M, respectively, the gel polymer electrolyte attains the maximum ionic conductivity (at 30 °C) of 4.63 mS cm⁻¹. Based on the gel polymer electrolyte, a quasi-solid state dye-sensitized solar cell was fabricated and its overall energy conversion efficiency of light-to-electricity of 3.10% was achieved under irradiation of 100 mW cm⁻².     

Li NMR, ionic conductivity and self-diffusion coefficients of lithium ion and solvent of plasticized organic-inorganic hybrid electrolyte based on PPG-PEG-PPG diamine and alkoxysilanes

Organic-inorganic hybrid electrolytes based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) (D2000) complexed with LiClO₄ via the co-condensation of an epoxy trialkoxysilane and tetraethoxysilane have been prepared and plasticized by a solution of ethylene carbonate (EC)/propylene carbonate (PC) mixture (1:1 by weight). The cross-linked hybrid network shows no solvent exudation and retains a large amount of plasticizer over 70 wt.% in stable state. The in situ built in silica network provides the hybrid electrolytes with good mechanical properties. The ionic conductivity of the dry hybrid electrolyte films was enhanced by two orders of magnitude via plasticization, reaching a maximum conductivity value of 4.0 × 10⁻³ S/cm at 30 °C. Variable temperature ⁷Li-{¹H} magic angle spinning (MAS) NMR demonstrated that the Li⁺ cations can be complexed by the polymer network as well as by the plasticizing solvents, but not with the incorporated silica network. Furthermore, the ⁷Li chemical shift change indicated a progressive change in the lithium coordination from lithium-polymer to lithium-solvent with increasing temperatures. The role of the solvents and the mobility of the lithium ions were investigated by pulsed gradient spin echo (PGSE) NMR measurements to elucidate the behavior of the ionic conductivity.     

离子液体中片状纳米ZnO的制备、表征及其光催化性能

采用一步合成法制备了离子液体1-庚基-3-甲基咪唑溴盐([C7mim]Br),以该离子液体为反应介质,在常压下制备了片状纳米ZnO粉体。用场发射扫描电子显微镜、X射线衍射、傅立叶转换红外光谱等对片状纳米ZnO粉体进行表征,结果表明,在该体系下离子液体作为溶剂及模板剂制备出具有六方纤锌矿结构片状聚集体,平均厚度约为20 nm,平均长和宽约为190 nm。以高压汞灯为光源,以ZnO纳米片为光催化剂,对有机染料罗丹明B进行光降解实验,结果表明,经过145 min后罗丹明B的去除率达到了96.4%,具有良好的光催化活性。     

Viscosity of binary mixtures. I. mono-, di-, and tri-n-butyl and -n-octylamine with cyclohexane

Viscosities for six binary mixtures of n-butylamine, di-n-butylamine, tri-n-butylamine, n-octylamine, di-n-octylamine, and tri-n-octylamine with cyclohexane have been measured at 303.15 K with an Ubbelohde suspendedlevel viscometer. Deviations of viscosities from a rectilinear dependence on mole fraction are attributed to H-bonding and to the size of alkylamine compounds. The application of the Eyring's theory of activation energy is examined. The free volume theory of Prigogine-Flory-Patterson (PFP) and the experimental excess enthalpy have been used to estimate excess viscosity ln = (ln / ₁ ⁰ – x ₂ ln ₂ ⁰ / ₁ ⁰ ) and corresponding free volume, enthalpy, and entropy contributions for five binary mixtures of tri-n-alkylamine: triethyl, tripropyl, tributyl, trihexyl, and trioctylamine with cyclohexane. A comparison of experimental and theoretical excess viscosities indicates a failure of the PFP theory when two components of the mixture differ considerably in size. The size difference contribution to excess viscosity is related to (V ₂ ^*1/2 – V ₁ ^*1/2 ), where V ₁ ^* and V ₂ ^* are hard-core volumes of two components of the mixture.