Cerium

Distribution by Scientific Domains
Distribution within Chemistry

Terms modified by Cerium

  • cerium ion

  • Selected Abstracts


    Fabrication and Application of a Novel Modified Electrode Based on Multiwalled Nanotubes/Cerium(III) 12-Tungstophosphoric Acid Nanocomposite

    ELECTROANALYSIS, Issue 11 2008
    Bin Fang
    Abstract A novel multiwalled nanotubes (MWNTs)/Cerium(III) 12 - tungstophosphoric acid (CePW) nanocomposite film glassy carbon electrode was prepared in this paper. Electrochemical behaviors of the CePW/MWNTs modified electrode were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This modified electrode brought new capabilities for electrochemical devices by combining the advantages of carbon nanotubes, rare-earth, and heteropoly-acids. The results demonstrated that the CePW/MWNTs modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine in 0.1,M PBS (pH,7.0). The experimental parameters were optimized and a direct electrochemical method for the simultaneous determination of guanine and adenine was proposed. The detection limit (S/N=3) for guanine and adenine was 2.0×10,8,M and 3.0×10,8,M, respectively. Further, the acid-denatured calf thymus DNA was also detected and the result was satisfied. [source]


    Stripping Voltammetry of Cerium(IIl) with a Chemically Modified Carbon Paste Electrode Containing Functionalized Nanoporous Silica Gel

    ELECTROANALYSIS, Issue 2 2008
    Mehran Javanbakht
    Abstract This research introduces the design of an adsorptive stripping voltammetric method for the cerium(III) determination at a carbon paste electrode, chemically modified with dipyridyl-functionalized nanoporous silica gel (DPNSG-CPE). The electroanalytical procedure comprised two steps: the Ce(III) chemical accumulation at ,200,mV followed by the electrochemical detection of the Ce(III)/dipyridyl complex, using anodic stripping voltammetry. The factors, influencing the adsorptive stripping performance, were optimized including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The resulting electrode demonstrated a linear response over a wide range of Ce(III) concentration (1.0,28,ng mL,1). The precision for seven determinations of 4 and 10,ng mL,1 Ce(III) was 3.2% and 2.5% (relative standard deviation), respectively. The prepared electrode was used for the cerium determination in real samples and very good recovery results were obtained. [source]


    Oxidative Inorganic Multilayers for Polypyrrole Film Generation

    ADVANCED FUNCTIONAL MATERIALS, Issue 13 2010
    Mikko Salomäki
    Abstract A controlled nanoscale fabrication of conducting polymer films sets severe requirements for the preparation method and substrate. A new and versatile approach for producing thin polypyrrole films on a variety of surfaces is presented. Purely inorganic thin films are first prepared from poly(metaphosphate) and tetravalent metal ions using a sequential layer-by-layer technique. Redox-active cerium(IV) polyphosphate multilayer and redox-inactive zirconium(IV) and hafnium(IV) polyphosphate multilayers are prepared. Cerium-based polyphosphate films grow exponentially with the number of layers but multilayers containing zirconium or hafnium exhibit a linear buildup process. All the studied systems produce relatively smooth films with initial bilayer thickness less than 2,nm. The cerium(IV) containing film is redox-active, which is shown by its capability to form a polypyrrole layer on its surface by oxidation of pyrrole monomers in the adjacent aqueous solution. This is a general method to produce thin oxidative films of arbitrary size and form on a wide variety of surfaces. [source]


    Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in Water

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009
    Habib Firouzabadi
    Abstract In this article a new environmentally friendly catalytic method is described for the efficient monoiodination and bromination of arenes and also iodoetherification and iodolactonization of olefins using hydrogen peroxide as the terminal oxidant. The method is based on using sodium iodide or sodium bromide, hydrogen peroxide (35%) and cerium(III) chloride as an effective catalyst in water at room temperature or under reflux conditions. By this protocol, iodination of anilines proceeded with high regioselectivity at the para position with the formation of small amounts of the ortho isomers. However, bromination of anilines proceeded with absolute regioselectivity to give the para isomers as the sole products in high yields. Iodinations and brominations of m -xylene, toluene, chloro- and bromobenzenes were proceeded with excellent regioselectivity to produce the para isomers as the sole products. Benzene was also halogenated by this catalytic system to give the monohalogenated benzene in good yields. Iodoetherification and iodolactonization of olefins also proceeded easily in high yields at room temperature. However, the bromination of olefins by this protocol failed and the starting materials were detected intact. [source]


    Allylation of Aldehydes Promoted by the Cerium(III) Chloride Heptahydrate/Sodium Iodide System: the Dependence of Regio- and Stereocontrol on the Reaction Conditions

    ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-13 2005
    G. Bartoli
    Abstract The cerium(III) chloride heptahydrate/sodium iodide complex (CeCl3,,,7,H2O/NaI) acts as a useful promoter in the carbon-carbon bond forming reaction by addition of allyltributylstannanes to aldehydes. The reaction of 2-butenyltributylstannane shows that the regio- and the stereochemical outcomes depend on the reaction conditions. When the promoter is adsorbed on a solid support (aluminum oxide), a highly prevalent formation of the ,-adduct is observed in solvent-free conditions. Conversely, when the reaction is carried out in acetonitrile as the solvent, the ,-adduct largely prevails. In the last case, a complete stereocontrol is observed, the less stable (Z)-isomer being obtained in high geometrical purity. [source]


    Synthesis and Characterization of Nanoscaled Cerium (IV) Oxide via a Solid-State Mechanochemical Method

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2006
    Jun Lu
    Solid-state reactions have the potential for direct preparation of ceramic powders and offer a low-temperature and low-cost alternative to conventional techniques for production of oxide powders. This paper describes a simple and effective mechanochemical method based on solid-state reactions during ball milling for synthesis of nanoscaled ceria (CeO2) particles. By using an organic base instead of an inorganic base, metal-ion-free nanoscaled CeO2 can also be made. The effects of annealing temperature on particle sizes and lattice strain are investigated. The results show that the average particle sizes of the particles increases and the average crystal lattice distortion decreases with the annealing temperature. Transmission electron microscopy examinations demonstrate that the CeO2 particles synthesised by this method are near-spherical shaped. [source]


    Effect of pH of Medium on Hydrothermal Synthesis of Nanocrystalline Cerium(IV) Oxide Powders

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2002
    Nan-Chun Wu
    Well-crystallized cerium(IV) oxide (CeO2) powders with nanosizes without agglomeration have been synthesized by a hydrothermal method in an acidic medium by using cerium hydroxide gel as a precursor. The relationship between the grain size, the morphology of the CeO2 crystallites, and the reaction conditions such as temperature, time, and acidity of the medium was studied. The experiments showed that with increasing reaction temperature and time, the CeO2 crystallites grew larger. The crystallites synthesized in an acidic hydrothermal medium were larger and had a more regular morphology than the ones synthesized in a neutral or alkaline medium when the reaction temperature and time were fixed. The CeO2 crystallites synthesized in an acidic medium were monodispersed; however, there was vigorous agglomeration among the grains synthesized in a neutral or alkaline medium. It was demonstrated that the hydrothermal treatment was an Ostwald ripening process and the acidity (pH) of the used hydrothermal medium played a key role in the dissolution of smaller grains. It is proposed that the dissolution process can control the kinetics of the growth of larger grains. [source]


    Growth and cathodoluminescent characteristics of blue emitting cerium-doped zinc aluminate layers synthesized by spray pyrolysis technique

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2004
    M. García-Hipólito
    Abstract Cerium doped ZnAl2O4 cathodoluminescent films have been deposited by ultrasonic spray pyrolysis deposition technique. X-ray diffraction measurements on these layers have shown that their crystalline structure depends on the substrate temperature. Cerium ions have been introduced into zinc aluminate films for produce violet-blue cathodoluminescence emissions. The behavior of cathodoluminescence emission intensity has been studied, as a function of the variations on doping concentrations, in the start spraying solution, substrate temperatures and the electron accelerating voltage. Concentration quenching of the cathodoluminescence occurs at about 0.8 percent of activator (Ce) concentrations inside the synthesized films. The surface morphology characteristics of these films, as a function of the substrate temperature, and the chemical composition, as measured by energy dispersive X-ray spectroscopy, are also exhibited. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    ChemInform Abstract: Cerium(III) Chloride Heptahydrate,Lithium Iodide: A Novel Reagent System for the Synthesis of N-Arylpyrrolidines.

    CHEMINFORM, Issue 11 2010
    J. S. Yadav
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    ChemInform Abstract: Liquid-Phase Oxidation of Some Aromatic Aldehydes, Hydrocarbons, and Alcohols by Cerium(IV) Catalyzed by Iridium(III) in Acidic Medium.

    CHEMINFORM, Issue 43 2009
    Praveen K. Tandon
    Abstract 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. [source]


    ChemInform Abstract: Cerium(III) Chloride Catalyzed One-Pot Synthesis of Tetrahydrobenzo[b]pyrans

    CHEMINFORM, Issue 26 2009
    Gowravaram Sabitha
    Abstract 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. [source]


    ChemInform Abstract: A Facile Procedure for Acetalization of Aldehydes and Ketones Catalyzed by Cerium(III) Trifluoromethanesulfonate.

    CHEMINFORM, Issue 23 2009
    Fumiaki Ono
    Abstract 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. [source]


    ChemInform Abstract: Cerium(IV) Ammonium Nitrate Catalyzed Facile and Efficient Synthesis of Polyhydroquinoline Derivatives Through Hantzsch Multicomponent Condensation.

    CHEMINFORM, Issue 49 2008
    Cherkupally Sanjeeva Reddy
    Abstract 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. [source]


    ChemInform Abstract: Pentadecatungstate with Dinuclear Cerium(III) Unit: Synthesis, Crystal Structure and Properties.

    CHEMINFORM, Issue 40 2008
    Taohai Li
    Abstract 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. [source]


    Cerium(IV) Ammonium Nitrate (CAN) as a Catalyst in Tap Water: A Simple, Proficient and Green Approach for the Synthesis of Quinoxalines.

    CHEMINFORM, Issue 23 2006
    Shivaji V. More
    Abstract 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, please click on HTML or PDF. [source]


    Remarkably Efficient Oxidative Coupling of N,N-Dialkylarylamines in Water Mediated by Cerium(IV) Ammonium Nitrate.

    CHEMINFORM, Issue 38 2005
    Chanjuan Xi
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Chemoselective Allylation of Aldehydes Using Cerium(III) Chloride: Simple Synthesis of Homoallylic Alcohols.

    CHEMINFORM, Issue 23 2005
    J. S. Yadav
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Cerium(III)-Catalyzed Cyclizations with 1-Cyanomethylene Tetrahydroisoquinoline: Substituent Controlled Formation of Fused Pyrroles or Pyridines.

    CHEMINFORM, Issue 38 2004
    Zoltan Vincze
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Cerium(III) Triflate versus Cerium(III) Chloride: Anion Dependence of Lewis Acid Behavior in the Deprotection of PMB Ethers.

    CHEMINFORM, Issue 36 2004
    Giuseppe Bartoli
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Mild and Chemoselective Catalytic Deprotection of Ketals and Acetals Using Cerium(IV) Ammonium Nitrate.

    CHEMINFORM, Issue 10 2004
    Ali Ates
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Esterification of Alkene with Cerium(IV) Sulfate in Carboxylic Acid.

    CHEMINFORM, Issue 2 2004
    C. Akira Horiuchi
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Amorphous Cerium,Titanium Solid Solution Phosphate as a Novel Family of Band Gap Tunable Sunscreen Materials.

    CHEMINFORM, Issue 36 2003
    Nobuhito Imanaka
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    Oxidation of Alcohols Using Cerium(IV) Alkyl Phosphonate Modified Silica.

    CHEMINFORM, Issue 18 2003
    Nazli Al-Haq
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]


    ChemInform Abstract: Cerium(III) Chloride Promoted Highly Regioselective Ring Opening of Epoxides and Aziridines Using NaN3 in Acetonitrile: A Facile Synthesis of 1,2-Azidoalcohols and 1,2-Azidoamines.

    CHEMINFORM, Issue 25 2002
    Gowravaram Sabitha
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    ChemInform Abstract: Thermodynamic Assessment of the Ag,Ce (Silver,Cerium) System.

    CHEMINFORM, Issue 15 2002
    Fucheng Yin
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    ChemInform Abstract: An Efficient Bromination of Alkenes Using Cerium(IV) Ammonium Nitrate (CAN) and Potassium Bromide.

    CHEMINFORM, Issue 1 2002
    Vijay Nair
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    ChemInform Abstract: A Highly Efficient, Mild, and Selective Cleavage of ,-Methoxyethoxymethyl (MEM) Ethers by Cerium(III) Chloride in Acetonitrile.

    CHEMINFORM, Issue 32 2001
    Gowravaram Sabitha
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    ChemInform Abstract: Cerium(IV) Ammonium Nitrate Mediated Nitration of Coumarins.

    CHEMINFORM, Issue 27 2001
    N. Ganguly
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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. [source]


    Fabrication and Application of a Novel Modified Electrode Based on Multiwalled Nanotubes/Cerium(III) 12-Tungstophosphoric Acid Nanocomposite

    ELECTROANALYSIS, Issue 11 2008
    Bin Fang
    Abstract A novel multiwalled nanotubes (MWNTs)/Cerium(III) 12 - tungstophosphoric acid (CePW) nanocomposite film glassy carbon electrode was prepared in this paper. Electrochemical behaviors of the CePW/MWNTs modified electrode were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This modified electrode brought new capabilities for electrochemical devices by combining the advantages of carbon nanotubes, rare-earth, and heteropoly-acids. The results demonstrated that the CePW/MWNTs modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine in 0.1,M PBS (pH,7.0). The experimental parameters were optimized and a direct electrochemical method for the simultaneous determination of guanine and adenine was proposed. The detection limit (S/N=3) for guanine and adenine was 2.0×10,8,M and 3.0×10,8,M, respectively. Further, the acid-denatured calf thymus DNA was also detected and the result was satisfied. [source]


    Growth and optical characterization of cerium and lead-doped Bi12TiO20 sillenite single crystals

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2005
    J. F. Carvalho
    Abstract Bi12TiO20 (BTO) single crystals doped with PbO and CeO2 were grown by the Top Seeded Solution Growth (TSSG) technique from the liquid phase with nominal compositions of 10Bi2O3 : (1,x)TiO2 : x PbO and 10Bi2O3 : (1,x)TiO2 : xCeO2 with x = 0.25 and 0.10. No growth-related difficulties were encountered other than those typical of sillenite crystals. Samples with good optical quality were obtained and were characterized by optical absorption, dark current, spectral photocurrent dependence, optical activity and electro-optic coefficient measurements. A comparison is made of the results of the optical measurements of doped and undoped BTO crystals. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]