Catalytic Ketonization of Carboxylic Acids Synthesis of Saturated and Unsaturated Ketones

Activity of 20wt% MO₂/Al₂O₃ catalysts, where M = Mn, Ce and Zr has been studied in ketonisation of the mixtures of propanoic/pentanoic, ethanoic/10-undecenoic and hexanoic/(Z)-9-octadecenoic (oleic) acids. Irrespective of the molecular weights and molar ratios of reacting acids, high yields of ketones were obtained over Mn and Ce oxide catalysts at approximately 673 K. Isomerization of C=C double bonds and partial pyrolysis occurred during catalytic ketonization of 10-undecenoic and oleic acids, diminishing slightly the yield of ketones. The preparation of (Z)-14-tricosen-6-one has been performed, being the starting material for the synthesis of (Z)-9-tricosene - sex attractant of male house fly.     

An expeditious synthesis of isoxazoline using cetyltrimethylammonium cerium nitrate: A phase transferring oxidative 1, 3-diplor cycloaddition

An expeditious and effective method for synthesis of isoxazoline from aldoximes and activated alkenes using cetyltrimethylammonium cerium nitrate at room temperature is described. Reaction was completed within short time period in high yields at room temperature.     

ChemInform Abstract: Structure,Magnetic and Electrical Properties of CeIrSb and Its Hydride CeIrSbH0.8.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

一种新奇的d-f异双核配合物[Fe(phen)3]2[FeCe(tiron)3]·6H2O的水热合成、晶体结构和磁性

硝酸铁,硝酸铈,邻菲咯啉(phen)和钛铁试剂(Tiron)通过水热方法合成了一种d-f异双核配合物 [Fe(phen)₃]₂[FeCe(tiron)₃]·6H₂O,tiron=C₆H₂O₈S₂。X-射线单晶衍射分析表明,晶体属立方晶系,P2₁3空间群,晶胞参数为：a=2.194 09(4) nm,V=10.562 4(3) nm³,Z=4,F(000)=4 648,R₁=0.045 1,wR₂=0.107 7,S=1.072。在具有C₃对称性的[FeCe(tiron)₃]^6-单元中,Fe(Ⅲ)与6个酚氧配位形成一个反三棱柱配位多面体,Ce(Ⅲ)则与3个桥联的酚氧μ₂-O和3个磺酸基的氧形成另一个与FeO₆共用底面的反三棱柱配位多面体CeO₆。配阳离子通过phen-phen之间的π-π相互作用和与配阴离子间的静电引力等作用组装成一种三角梅状准主/客体型的超分子。在2～300 K温度范围内测试了配合物的变温磁化率,结果表明, Ce(Ⅲ)-Fe(Ⅲ)之间存在典型的反铁磁性相互作用。     

Spectrophotometric and Fluorimetric Methods for the Determination of Methoxamine Hc1 in Bulk Drugs and in Ampoules

Abstract

Three simple and sensitive methods for the determination of methoxamine HCl in bulk drugs and in ampoules were proposed. The methods are based on the oxidation of methoxamine HCl by sodium periodate, potassium permanganate and cerium(IV)sulphate. The first two reactions are followed spectrophotometrically by measuring the absorbance at 352 &; 608 nm for the periodate and permanganate methods, respectively. The third method is based on measuring the relative fluorescence intensity of Ce(III)arising from Ce(IV) at 348 nm with excitation wavelength at 257 nm. The different experimental parameters were carefully studied. Under the described conditions the proposed methods were applicable over the concentration ranges 10.0 - 40.0, 2.0-10.0 and 0.05-0.30 μg ml^?1 for the three methods, respectively.     

Magnetic behaviors of cerium oxide-based thin films deposited using electrochemical method

Zn and Co multi-doped CeO2 thin films have been prepared using an anodic electrochemical method. The structures and magnetic behaviors are characterized by several techniques, in which the oxygen states in the lattice and the absorptive oxygen bonds at the surface are carefully examined. The absorptive oxygen bond is about 50% of the total oxygen bond by using a semi-quantitative method. The value of actual stoichiometry δ is close to 2. The experimental results indicate that the thin films are of a cerium oxide-based solid solution with few oxygen vacancies in the lattice and many absorptive oxygen bonds at the surface. Week ferromagnetic behaviors were evidenced by observed M–H hysteresis loops at room temperature. Furthermore, an evidence of relative ferromagnetic contributions was revealed by the temperature dependence of magnetization. It is believed that the ferromagnetic contributions exhibited in the M–H loops originate from the absorptive oxygen on the surface rather than the oxygen vacancies in the lattice.     

Preparation of Magnetically Recyclable Yolk/Shell FexOy/PdPt@CeO2 Nanoreactors with Enhanced Catalytic Activity

Noble metal nanoparticles (NPs) have recently received considerable attention from researchers working in the field of catalysis. However, the development of new methods allowing these materials to reach their maximum catalytic properties remains challenging. Nanoreactors could lead to dramatic improvements in activity with the help of the intrinsic confinement effect. In this study, we designed a series of yolk/shell Fe_xO_y/PdPt@CeO₂ composites, where the Fe_xO_y NPs acted as a movable core, allowing for the uniform distribution of the PdPt alloys on the inner surface of the CeO₂ shell. The high porosity and existence of hollow voids in the CeO₂ shell allowed these Fe_xO_y/PdPt@CeO₂ composites to be used as nanoreactors in catalytic reactions. As well this confinement effect, we identified two structural features that led to enhanced catalytic activity, including (i) the replacement of monometallic NPs with a bimetallic PdPt alloy and (ii) the replacement of a chemically inert support with a reactive CeO₂ shell. The resulting nanoassembled catalysts displayed higher activities toward the catalytic reduction of dyes than the reference samples. Moreover, these catalysts were readily recovered and reused because of the magnetic Fe_xO_y core.     

铈对锂铝合金阳极充放电性能的影响

研究了铈对锂铝合金阳极充放电性能的影响。在锂铝合金阳极中添加 0 5%～ 1 5% (质量分数 )铈 ,可增大电池的放电容量和电压 ,改善锂铝合金阳极的表面形貌。添加铈的多孔锂铝合金阳极具有理想的充放电性能。