层间阴离子对铝代Ni(OH)_2质子扩散系数的影响

采用化学共沉淀法制备了层间分别含有SO42-和NO3-的铝取代氢氧化镍样品。应用X-射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和循环伏安法(CV)对样品的微观结构和质子扩散系数进行了比较。结果表明,两样品均为α-相氢氧化镍,其中层间含有NO3-的铝代氢氧化镍比层间含有SO42-的铝代氢氧化镍具有更好的结晶特性;循环伏安测试表明,层间含有NO3-的铝代氢氧化镍比层间含有SO42-的铝代氢氧化镍具有更好的电化学反应可逆性和更高的质子传递系数。     

Recognition of chiral carboxylic anions by artificial receptors

Many carboxylic molecules, ranging from drugs to flavors and fragrances, contain chiral centers. As a consequence, research has been carried out in order to design and synthesize artificial receptors for carboxylic anions. Many problems have to be solved for binding anions. The results obtained in the binding of carboxylic anions by guanidine, secondary ammonium and metal-center have been selected. The last part of this review focuses on chiral recognition of carboxylic anions by organic and metal-based chiral receptors.     

醇钠法合成一缩二丙二醇的工艺过程控制

介绍了一缩二丙二醇的用途及合成方法,重点阐述了以乙醇钠为催化剂,用丙二醇和环氧丙烷在一定温度和压力条件下合成一缩二丙二醇的反应原理和工艺流程,从反应温度、压力、精馏方式、催化剂回收等方面对生产工艺过程控制进行了探讨,总结出一种效率高,成本低,质量好的一缩二丙二醇的生产工艺条件。     

Study of the factors determining the mobility of ions in the polypyrrole films doped with aromatic sulfonate anions

The electrochemical redox behavior of the polypyrrole (PPy) films doped with benzenesulfonate (BS), p-toluenesulfonate (pTS) and naphtalene-1,5-disulfonate (NDS) was investigated by cyclic voltammetry, the chemical composition of the films was determined by XDS, the surface morphology was characterized by AFM, and the interactions between pyrrole oligomers and the anions were modeled with quantum chemical methods. It is the first detailed comparative study of the properties of these interesting systems with two complementing interactions (electrostatic and aromatic stacking). It was shown than these relatively similar aromatic sulfonate anions have rather different behavior in PPy films. The results showed that the redoxactivity of polypyrrole films doped with sulfonate ions increases in the sequence pTS < BS < NDS. The comparison of voltammograms measured in the presence of different anions with PPy films synthesized in the same solution show that the PPy/pTS films have the most densely packed and the PPy/NDS films the least densely packed structure of the three. The mobility of ions in these films is mainly determined by the packing of the films, which in turn partly depends on the interactions between the dopant-anion and polymer chains.     

Growth Mechanism of Monodispersed ZrO2 Particles

Monodispersed ZrO₂ seed particles which were prepared by hydrolysis of zirconium alkoxide solutions were allowed to grow by further addition of zirconium alkoxide and water under conditions in which new particles do not nucleate and grow. The particle growth mechanism is presumed to be a surface reaction in which the rate-determining step is a first-order polynuclearlayer growth mechanism. With this method of powder preparation, it is possible to precisely control the particle size, and it may be useful for applications in ceramic processing.     

Hydrolytic Condensation of Tin(IV) Alkoxide Compounds to Form Particles with Well-Defined Morphology

The sol-gel-type condensation of tin(IV) ethoxide [Sn(OEt)₄] n (where OEt is ethoxide) under basic conditions produced spherical, submicrometer-sized tin(IV) oxide (cassiterite) particles. Transmission electron microscopy and powder X-ray diffraction data indicated that the grain size was approximately 20 to 30 Å (2 to 3 nm). The mixed-metal alkoxide compound [ZnSn(OEt)₆] was hydrolyzed under analogous conditions to give either spherical or octahedral submicrometer-sized crystalline particles of ZnSn(OH)₆ depending on the solvents used. These data demonstrated that the stoichiometry of the mixed-metal alkoxide precursor was retained during condensation. Thermal treatment of ZnSn(OH)₆ resulted in crystallization of ZnSnO₃ at approximately 676°C. At neutral pH, hydrolysis of [ZnSn(OEt)₆] resulted in formation of a high surface area (261 m²/g) amorphous powder.     

Hydrogen‐Terminated Si Nanowires as Label‐Free Colorimetric Sensors in the Ultrasensitive and Highly Selective Detection of Fluoride Anions in Pure Water Phase

The detection of anions in pure water phase with colorimetric sensor is a long standing challenge. As one of the most important anions, F^– is associated with nerve gases and the refinement of uranium for nuclear weapons. However, limited by its anions nature, few of the reported colorimetric sensors can successfully applied to detect F^–1 in pure water phase. This work designs a colorimetric sensor for F^–1 pure water phase detection by taking the advantages of the strong specific binding between F and Si, as well as the color‐changing property of H‐terminated Si nanowires (SiNWs). The sensor demonstrates ultra‐sensitivity, high selectivity, and good stability. The results reveal particular interest for the development of new type aqueous phase anions sensors with SiNWs.     

Oxygen reduction on oxide/polypyrrole composite electrodes: effect of doping anions

Multilayered composite electrodes on glassy carbon, GC, having the structure GC/PPy/PPy(Ox)/PPy, with PPy the polypyrrole and Ox a mixed valence oxide of transition metals, exhibit high reactivity and stability towards the oxygen reduction reaction (orr), when the orr proceeds electrocatalytically on the oxide particles dispersed throughout the inner layer, PPy(Ox). However the nature and concentration of the doping anions, A, of PPy have a profound effect on the resulting orr currents, due to their effects on the conductivity and morphology of the PPy layers. The paper shows and discusses these effects in the case of the composite electrode with Ox = Cu_1.4Mn_1.6O₄ and A = Cl⁻, ClO₄⁻, NO₃⁻, PF₆⁻ and SO₄²⁻, in acid solution (pH 2.2). Optimal conditions were encountered with Cl⁻.     

金属醇盐配合物与纳米钛酸铅的制备

在C[(Bu4)Br]=0．03mol／L的乙醇溶液中，保持温度50℃电解钛片4h，40℃电解铅片2h，每隔30min；0．1mL乙酰丙酮，制得铅、钛金属醇盐PbTi(OCH2CH3)(6-y)(acac)y，采用红外、拉曼光谱等测试技术对纳米PbTiO3前驱体进行了表征。前驱体中含有乙酰丙酮基团(acac^-)。凝胶经乙醇洗涤、真空干燥24h后，700℃煅烧2h制得纳米PbTiO3粉体。采用X-射线衍射、电子透射技术等手段对纳米PbTiO3进行了表征，干凝胶粒径为10nm，纳米PbTiO3粒径为10-15nm。