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    Chinese Journal of Catalysis
    2011, Vol. 32, No. 1
    Online: 13 January 2011

    Cover:

    Zhou and coworkers in their article on pages 27–30 reported the selective catalytic hydrogenation of acetylene to produce ethylene on a MoP catalyst. The MoP catalyst showed high acetylene hydrogenation activity and selectivity.

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    Table of Contents
    Table of Contents for Vol.32 No. 1
    2011, 32 (1):  0-0. 
    Abstract ( 1454 )   PDF (2272KB) ( 803 )  
    Summary
    Progress in Ru-Based Amorphous Alloy Catalysts for Selective Hydrogenation of Benzene to Cyclohexene
    SUN Haijie, GUO Wei, ZHOU Xiaoli, CHEN Zhihao, LIU Zhongyi*, LIU Shouchang
    2011, 32 (1):  1-16.  DOI: 10.1016/S1872-2067(10)60154-4
    Abstract ( 3953 )   [Full Text(HTML)] () PDF (782KB) ( 2097 )  
    Ru-based amorphous alloy catalysts prepared by the chemical reduction method have high activity and excellent cyclohexene selectivity due to their structure that has the merits of amorphous alloys and nano-particles. In particular, the supported catalysts have the advantages of better utilization of the Ru noble metal and ease of use in industry. The thermodynamics and kinetics for selective hydrogenation of benzene to cycohexene over these catalysts, and the influence of the structure and composition of the catalysts were described. The reaction conditions, ability to modify the catalysts, and results of pilot tests were emphasized. Directions in this field for future research were suggested.
    NOx Storage-Reduction Catalysis and Structure-Performance Relationship of Pt-BaO Catalyst
    HU Zhun, SUN Keqiang*, XU Boqing
    2011, 32 (1):  17-26.  DOI: 10.3724/SP.J.1088.2011.00904
    Abstract ( 3054 )   [Full Text(HTML)] () PDF (621KB) ( 1171 )  
    NOx storage-reduction (NSR) is one of the most promising techniques for lean NOx abatement. The periodical lean/rich conditions and the combination of the stoichiometric reaction and the catalytic reaction on NSR catalyst distinguish the NSR catalysis from conventional continuous gas-solid catalytic process. This paper summarized the knowledge and understanding of the NSR catalysis on supported Pt-BaO catalyst. The fundamental chemical processes over the NSR catalysts were discussed first, followed by the role of Pt, BaO and support material. Problems and prospects in the study of NSR catalysts were presented.
    Research Briefing
    Selective Hydrogenation of Acetylene over a MoP Catalyst
    ZHOU Guilin1, WANG Puguang2, JIANG Zongxuan1, YING Pinliang1, LI Can1,?
    2011, 32 (1):  27-30.  DOI: 10.1016/S1872-2067(10)60155-6
    Abstract ( 3870 )   [Full Text(HTML)] () PDF (488KB) ( 1317 )  
    A MoP catalyst was prepared by high temperature hydrogen reduction. Its properties were investigated by X-ray diffraction and in-situ X-ray photoelectron spectroscopy. It was used for the selective catalytic hydrogenation of acetylene. The results indicated that MoP is formed by hydrogen reduction at 650 °C. The prepared MoP catalyst contained high valence molybdenum and phosphorus species. The catalyst is a bifunctional catalyst, which includes a hydrogenation center and an electron-deficient center. Ethylene selectivity can exceed 73% when the acetylene conversion is higher than 99%.  
    Influence of Phosphine Concentration on Propylene Hydroformylation over the PPh3-Rh/SiO2 Catalyst
    YAN Li1,2, DING Yunjie1,2,*, LIU Jia1,2, ZHU Hejun1,2, LIN Liwu1,2
    2011, 32 (1):  31-35.  DOI: 10.1016/S1872-2067(10)60156-8
    Abstract ( 2888 )   [Full Text(HTML)] () PDF (491KB) ( 1004 )  
    The effect of triphenyl phosphine concentration in the novel PPh3-Rh/SiO2 catalyst for propylene hydroformylation was studied and found an optimum P/Rh ratio of 15, a butyraldehyde n#/em/em# ratio of 14, a butyraldehyde TOF of 241 h-1, and high catalytic stability for PPh3-Rh/SiO2. Solid-state 31P NMR shows that in an atmosphere of syngas the physically adsorbed PPh3 migrates onto the surface of Rh/SiO2 where it chemically adsorbs and then promotes the in situ formation of carbonyl phosphine complexes.
    Research papers
    Preparation and Photocatalytic Activity of Ag@AgCl Modified Anatase TiO2 Nanotubes
    WEN Yanyuan, DING Hanming*
    2011, 32 (1):  36-45.  DOI: 10.1016/S1872-2067(10)60157-X
    Abstract ( 3425 )   [Full Text(HTML)] () PDF (796KB) ( 1957 )  
    The combination of TiO2 nanotubes and a surface plasmon resonance (SPR) photocatalyst used their large adsorption capacity and wide visible light response, respectively, and a synergistic effect to enhance photocatalytic activity under visible light irradiation. Anatase TiO2 nanotubes were prepared by hydrothermal synthesis, a hydrogen peroxide treatment, and calcination at 400 oC. AgCl nanoparticles were then loaded onto the TiO2 nanotubes by a precipitation reaction, and some of the AgCl particles were reduced to Ag particles under halogen tungsten lamp irradiation. This gave a visible light SPR photocatalyst of Ag@AgCl/TiO2 nanotubes that exhibited high photocatalytic activity, which was due to its large adsorption capacity, wide visible light response due to the SPR effect, fast separation of photogenerated electron-hole pairs, and strong oxidizing ability of Cl0 generated by combining Cl- ions with photoexcited holes. Methylene blue dye was thoroughly decolorized within 1 h in the presence of this photocatalyst under visible light irradiation. In addition, the photocatalyst was stable after recycling the photocatalytic reaction five times.
    Photocatalytic Conversion of Naphthalene to α-Naphthol Using Nanometer-Sized TiO2
    SHI Huixian1, ZHANG Tianyong1,2,*, WANG Hongliang3, WANG Xiao1, HE Meng1
    2011, 32 (1):  46-50.  DOI: 10.1016/S1872-2067(10)60158-1
    Abstract ( 3674 )   [Full Text(HTML)] () PDF (420KB) ( 1252 )  
    The effects of various parameters (co-solvents, electron acceptors, and surface modification) on the direct synthesis of α-naphthol from naphthalene using photocatalytic processes were investigated. The •OH radicals generated on UV-illuminated TiO2 photocatalysts led to the direct hydroxylation of naphthalene to α-naphthol. The addition of Fe3+, Fe2+, Fe3+ + H2O2, and Fe2+ + H2O2 greatly increases the conversion of naphthalene and the yield of α-naphthol in TiO2 suspensions. The addition of Fe3+ + H2O2 to a TiO2 suspension increased the yield to 22.2%. Surface modified-TiO2 had a significant influence on the hydroxylation reaction. La-Eu/TiO2, La-Y/TiO2, H3PW12O40/TiO2, H3PMo12O40/TiO2, Fe/TiO2, Ag/TiO2, Cu/TiO2, and N/TiO2 enhanced the conversion and yield more than TiO2. Fe/TiO2 has the highest photocatalytic efficiency among these species.
    Deactivation Modes of Solid Catalysts with Different Active Sites
    K. KUMBILIEVA1,*, L. PETROV2
    2011, 32 (1):  51-59.  DOI: 10.1016/S1872-2067(10)60159-3
    Abstract ( 2285 )   [Full Text(HTML)] () PDF (376KB) ( 905 )  
    An approach is suggested to distinguish different types of active sites responsible for different reactions on bifunctional catalysts. The model assumes a non-uniform vulnerability of active sites that depends on their location. Problems on the relationship between the dispersion of the active phase and selectivity are discussed. The effect of coke formation on the activity change of different sites is analyzed.
    Formylation of Alcohol with Formic Acid under Solvent-Free and Neutral Conditions Catalyzed by Free I2 or I2 Generated in Situ from Fe(NO3)3•9H2O/NaI
    Rostami AMIN1,*, Khazaei ARDESHIR2,#, Alavi-Nik HEIDAR ALI2, Toodeh-Roosta ZAHRA2
    2011, 32 (1):  60-64.  DOI: 10.1016/S1872-2067(10)60160-X
    Abstract ( 2848 )   [Full Text(HTML)] () PDF (282KB) ( 1706 )  
    Different alcohols were formylated by formic acid under solvent-free conditions in the presence of iodine as the catalyst with good-to-high yields at room temperature. I2 generated in situ from Fe(NO3)3·9H2O/NaI also catalyzed the formylation of the alcohols under solvent-free conditions. This gives a green and efficient reaction at room temperature, in which the use of toxic and corrosive molecular I2 is avoided.
    Synthesis of Chiral Functionalized Polymers by Alternating Copolymerization of Propene and CO Using the Pd(OAc)2/(S)-P-PHOS Catalyst
    WANG Lailai*, JIA Xiaojing, WAN Bo
    2011, 32 (1):  65-69.  DOI: 10.1016/S1872-2067(10)60161-1
    Abstract ( 3131 )   [Full Text(HTML)] () PDF (430KB) ( 984 )  
    Pd(OAc)2 (palladium acetate)/(S)-P-PHOS ((S)-2,2′,6,6′-tetramethoxy-4,4′-bis(diphenyl)phosphino)-3,3′-bipyridine) catalysis systems were applied to the alternating copolymerization of propene and CO in organic solvents to synthesize chiral polyketones. The diastereoselective reduction of a chiral polyketone using excess LiAlH4 (lithium aluminum hydride) and NaBH4 (sodium borohydride) as reducing agents gave a new class of optically active polyalcohol and the product yield was more than 90%. In the presence of various amounts of NaBH4 (NaBH4/carbonyl molar ratio of 0.5, 1, and 2), quantitative measurements of the intensity of the carbonyl absorbance at 200–400 nm in the UV (ultraviolet) spectrum showed a reduction of 29%, 71%, and 81%, respectively, for the carbonyl groups. The use of excess BH3·THF (borane tetrahydrofuran complex) as a reducing agent resulted in a partial reduction of the carbonyl groups of the chiral polyketone. The molecular weight of the product was lower than that of the chiral polyketone and the molar optical rotations of the product varied with the reductive conditions.
    Hydroxyapatite Supported Lewis Acid Catalysts for the Transformation of Trioses in Alcohols
    ZHANG Zehui1,2,*, ZHAO (Kent) Zongbao1,3
    2011, 32 (1):  70-73.  DOI: 10.1016/S1872-2067(10)60162-3
    Abstract ( 2750 )   [Full Text(HTML)] () PDF (425KB) ( 928 )  
    We prepared hydroxyapatite-supported tin(II) chloride and tin(IV) chloride Lewis acid catalysts. These catalysts showed catalytic activity for the transformation of trioses in alcohols to yield alkyl lactates. Under optimal conditions, n-butyl lactate was obtained in 73.5% yield when dihydroxyacetone and n-butanol were treated with hydroxyapatite-supported tin(II) chloride.
    Pt-Au/CNT@TiO2 as a High-Performance Anode Catalyst for Direct Methanol Fuel Cells
    WANG Xiuyu, ZHANG Jingchang*, ZHU Hong
    2011, 32 (1):  74-79.  DOI: 10.1016/S1872-2067(10)60163-5
    Abstract ( 3464 )   [Full Text(HTML)] () PDF (539KB) ( 1357 )  
    Multi-walled carbon nanotubes (CNT) modified using TiO2 nanoparticles (CNT@TiO2) were prepared. Then, Pt-Au/CNT@TiO2 catalysts were prepared by a deposition-UV-photoreduction method for direct methanol fuel cells. The physico-chemical properties of the catalysts were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performance was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The Pt-Au nanoparticles were found to be uniformly deposited onto the CNT@TiO2 support and had diameters of 2–3 nm. Compared with the Pt-Au/CNT catalyst that was made using a general chemical method, Pt-Au/CNT@TiO2 exhibits higher CO-tolerance for the following reasons. Firstly, the strong interaction between the Pt-Au alloy and TiO2 leads to an increase in electron density on the metallic Pt-Au, which transfers electrons to the πCO* orbital of CO and weakens C–O binding while the oxidation overpotential is lowered. Secondly, the high-valence Ti ions dissociate water to form OHad (ad: adsorbed) species, which then reacts with the strongly bound COad on the Pt surface to form CO2.
    New Chiral Monophosphite Ligands Containing BINOL and/or H8-BINOL Bearing Adamantyl Substituents: Effect of Ligand Scaffold on the Enantioselective 1,4-Conjugate Addition of Diethylzinc to Cyclic Enones
    WAN Bo1, KWONG Fuk Yee2,#, WANG Lailai1,*, XU Lijin3, ZHAO Qinglu1, XING Aiping1
    2011, 32 (1):  80-85.  DOI: 10.1016/S1872-2067(10)60164-7
    Abstract ( 3507 )   [Full Text(HTML)] () PDF (433KB) ( 864 )  
    A series of new bulky monophosphite ligands were synthesized from axially chiral BINOL/H8-BINOL (BINOL: 1-(2-hydroxynaphthalen-1-yl)naphthalen-2-ol) and highly sterically hindered adamantylcarbonyl chloride. The effectiveness of these ligands was evaluated by the Cu-catalyzed asymmetric 1,4-conjugate addition of diethylzinc to cyclic enones with enantioselectivities of up to 79% ee. The results showed that a ligand structure comprising a partially hydrogenated 2,2′-(1,1′-binaphthyl)phosphite scaffold and an adamantyl moiety was effective in improving the enantioselectivity.
    Effect of Pt Oxidation State on Methanol Oxidation Activity
    ZENG Jianhuang, SHU Ting, LIAO Shijun, LIANG Zhenxing*
    2011, 32 (1):  86-92.  DOI: 10.1016/S1872-2067(10)60165-9
    Abstract ( 4108 )   [Full Text(HTML)] () PDF (566KB) ( 3090 )  
    Pt catalysts supported on Vulcan XC-72 carbon were prepared by the NaBH4 reduction of H2PtCl6 in the presence of a carbon support. One of the catalysts was deliberately treated with H2O2 after chemical reduction to alter the oxidation state of Pt and to promote methanol oxidation through more efficient water dissociation on the Pt sites. X-ray photoelectron spectroscopy confirmed that H2O2 treatment resulted in a more oxidized Pt catalyst. The electrooxidation of methanol over treated and untreated Pt catalysts in acidic solutions at room temperature was investigated by cyclic voltammetry and chronoamperometry. Despite their design, the more oxidized Pt catalysts could not supply active oxygen capable of removing the reaction-inhibiting CO-like reaction intermediates. As a result the catalytic activity was still largely dependent on the Pt oxidation state with the more “metallic” catalyst showing higher methanol oxidation activity and more CO tolerance.
    Effect of Calcination Atmospheres on the Performance of Ru/Al2O3 Catalyst for Partial Oxidation of Methane to Syngas
    ZHENG Haozhuan1, WANG Meiliu1, HUA Weiqi2, WENG Weizheng1,*, YI Xiaodong1, HUANG Chuanjing1, WAN Huilin1,*
    2011, 32 (1):  93-99.  DOI: 10.3724/SP.J.1088.2011.00643
    Abstract ( 3400 )   [Full Text(HTML)] () PDF (705KB) ( 1155 )  
    The catalytic performance for partial oxidation of methane (POM) to syngas over the Ru/Al2O3 catalyst calcined in air (Ru/Al2O3-Air) and Ar (Ru/Al2O3-Ar) was studied. Steady-state reactivity was observed on the Ru/Al2O3-Ar sample, whereas oscillations in CH4, CO, H2, CO2, and H2O were observed on the Ru/Al2O3-Air sample. Comparative studies using CO and O2 chemisorption, X-ray diffraction, Raman, and temperature-programmed reduction (TPR) techniques were carried out in order to elucidate the property-structure relationship of the samples. The Ru dispersion on Ru/Al2O3-Air was only 1%, whereas that on Ru/Al2O3-Ar was about 9%. The significant difference in the Ru dispersion on the two samples is the major factor affecting the POM reaction. Two types of Ru species, RuO2 species weakly interacting with Al2O3 and the Ru-O-Al species strongly interacting with the support, were identified by H2-TPR experiments on the fresh catalyst. The former species could be easily reduced by H2 (below 200 °C), while the latter can only be reduced by H2 at above 700 °C. During the POM reaction at above 600 °C, the RuO2 species were in the metal state, whereas the Ru-O-Al species could undergo cyclic redox transformation. Such transformation is responsible for the oscillation on Ru/Al2O3-Air sample.
    Influence of Pt Promoter on the Visible Light Photocatalytic Properties of N-Doped TiO2
    ZHENG Huarong, CUI Yanjuan, ZHANG Jinshui, DING Zhengxin, WANG Xinchen*
    2011, 32 (1):  100-105.  DOI: 10.3724/SP.J.1088.2010.00713
    Abstract ( 3100 )   [Full Text(HTML)] () PDF (505KB) ( 2830 )  
    The influence of Pt as a promoter on the photocatalytical performance of nitrogen-doped TiO2 was described. The sample was characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoelectrochemistry, and photoluminescence. The degradation of methyl orange in aqueous solution under visible light irradiation was used to evaluate the photocatalytic activity of the sample. The modification of N-TiO2 with Pt did not change the crystal structure and the mesoporous structure of TiO2. The loading of Pt enhanced the material absorption in visible light region, which is assigned to background absorption that has detrimental effect on photocatalytic activity. However, the highly dispersed Pt on the surface of N-TiO2 remarkably altered the surface structure (surface state) of N-TiO2, contributing largely to the enhanced photocatalytic activity of nitrogen-doped TiO2.
    Pilot Study on the Use of Methane Steam Reforming Catalyst in Molten Carbonate Fuel Cell
    LI Guanglong1,2, ZHOU Li1,*, WANG Yingxu1,2 , WANG Pengjie1, LIN Huaxin1, ZHU Xiuling2, SHAO Zhigang1
    2011, 32 (1):  106-110.  DOI: 10.3724/SP.J.1088.2010.00637
    Abstract ( 2775 )   [Full Text(HTML)] () PDF (660KB) ( 825 )  
    A methane steam reforming catalyst was selected by the comparison of its catalytic properties and resistance to carbon deposition. The performance of a molten carbon fuel cell (MCFC) using this catalyst was studied. The effect of discharge magnitude, gas pressure, and steam-carbon ratio (S/C) on the catalyst was also investigated. The results indicated that the catalyst could make the cell perform well, and the increment of the current affected the content of H2 in the cell, but it had minor effect on the content of CH4. In addition, the reforming reaction depended on the gas pressure. There was a maximal content of H2 in the cell at 0.36 MPa. With the decrease of S/C, the performance of MCFC was improved.
    Preparation and Characterization of Carbon-Covered Alumina Supported Ni Catalyst and Its Catalytic Performance for Hydrogenation of 1,4-Butanediol
    LI Haitao, CHEN Haoran, ZHANG Yin, GAO Chunguang, ZHAO Yongxiang*
    2011, 32 (1):  111-117.  DOI: 10.3724/SP.J.1088.2010.00729
    Abstract ( 3051 )   [Full Text(HTML)] () PDF (810KB) ( 1251 )  
    Carbon-covered alumina (CCA) was prepared by pyrolysis of sucrose dispersed on a γ-Al2O3 support, and 17% Ni/CCA catalyst was prepared by impregnation with CCA. Effect of carbon addition on the catalytic performance of Ni/Al2O3 was investigated for the hydrogenation of crude 1,4-butanediol aqueous solution. The catalyst samples were characterized by thermogravimetry-differential scanning calorimetry, scanning electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption, H2 temperature-programmed reduction, and X-ray diffraction. The results indicated that the addition of carbon resulted in the changes in the surface properties of the support, the nickel dispersion, and metal-support interaction of the catalyst, leading to different hydrogenation activity of the catalyst. When the carbon loading was 11.6%, the catalyst sample showed the highest nickel dispersion, the mild metal-support interaction and the highest activity for the hydrogenation of crude 1,4-butanediol solution.
    Selective Oxidation of Alcohols Catalyzed by a Transition Metal-Free System of NHPI/DDQ/NaNO2
    ZHOU Lipeng1, ZHANG Chaofeng1, FANG Tao1, ZHANG Bingbing1, WANG Ying1, YANG Xiaomei1,*, ZHANG Wei2, XU Jie2
    2011, 32 (1):  118-122.  DOI: 10.3724/SP.J.1088.2010.00734
    Abstract ( 3439 )   [Full Text(HTML)] () PDF (430KB) ( 1484 )  
    A transition metal?free catalyst composed of N-hydroxyphthalimide (NHPI), 2,3-dichloro-5,6-dicyano-benzoquinone (DDQ), and NaNO2 was studied for the selective oxidation of alcohols using O2 as oxidant. The reaction results showed that this catalyst system can effectively catalyze the oxidation of alcohols to the corresponding aldehydes or ketones. 99% selectivity for benzaldehyde at 65% conversion of benzyl alcohol was obtained at 80 °C for 6 h. In the process of reaction, DDQ abstracted a hydrogen atom from NHPI to generate a highly reactive PINO free radical and hydroquinone. Then, PINO abstracted a hydrogen atom from alcohols to generate aldehydes or ketones. Finally, NO from NaNO2 decomposition in the reaction media catalyzed the oxidation of hydroquinone to quinone by O2.
    Synthesis of Hyperbranched Polyester by Combination of Prepolymerization with Enzymatic Condensation Polymerization and Its Characterization
    LIN Zhijian1, LI Guangji1,*, LONG Junyuan1, ZONG Minhua2
    2011, 32 (1):  123-128.  DOI: 10.3724/SP.J.1088.2010.00623
    Abstract ( 2978 )   [Full Text(HTML)] () PDF (514KB) ( 1054 )  
    A new route for hyperbranched aliphatic polyester by the prepolymerization of comonomers followed by the enzymatic condensation polymerization in organic media was developed using glycerol, 1,6-hexanediol, and adipic acid as comonomers and using immobilized lipase Novozym 435 as a biocatalyst. The organic solvents, such as isooctane, toluene, tert-butanol, tetrahydrofuran, and acetone, were used as the reaction medium for enzymatic condensation polymerization. The effects of reaction medium and reaction temperature on the enzymatic condensation polymerization were investigated. The molecular mass and the structure of the prepared polyesters were characterized by gel permeation chromatography and NMR. The results indicated that the hyperbranched aliphatic polyester could be successfully synthesized under the mild conditions by the combination of prepolymerization of comonomers with enzymatic condensation polymerization in organic media. Toluene was the best reaction medium among the examined ones, and the lipase Novozym 435 exhibited the highest activity at 70 oC within the temperature range from 50 to 90 oC. The polyester prepared by prepolymerization and the enzymatic condensation polymerization in toluene at 70 oC possessed the maximal molecular mass of up to 1.31×104 and the branching degree of about 0.27.
    Preparation of Nano BiOCl Microsphere and Its Fabrication Machanism
    LIU Hongqi, GU Xiaona, CHEN Feng*, ZHANG Jinlong
    2011, 32 (1):  129-134.  DOI: 10.3724/SP.J.1088.2010.00738
    Abstract ( 3059 )   [Full Text(HTML)] () PDF (596KB) ( 2083 )  
    Nano BiOCl microsphere was prepared by the solvothermal method using glycol as solvent. The as-prepared nano microsphere was composed numerous BiOCl nanoplates, which are fabricated together to form opening microporous structure. The preparation of BiOCl under different solvothermal conditions indicated that the formation of nano microsphere follows a glycol-assisted growth process. Two oxygen atoms in glycol coordinate with one or two Bi3+ ions to produce Bi3+-containing complexes. During the solvothermal treatment, glycol molecules were condensed via the catalysis of Bi3+ ions to produce H2O, which promoted the hydrolysis of Bi3+-containing complexes and the formation of a Bi–O–Bi structure in turn. The Bi–O–Bi structure then combines the Bi3+ in the solution via the interlinking action of the glycol and leads to the formation of BiOCl substructure. The BiOCl substructure grows up radially from the crystal nucleus to form a nano microsphere structure. The surface microporous structure of the nano microsphere favors the adsorption and the mass exchange of the dyes, consequently, the as-prepared BiOCl nano microsphere exhibits a good dye-sensitized visible light photocatalytic activity.
    Preparation, Structure and Performance of Defected Perovskite BaCo1-xFexO3-δ Catalyst for NOx Storage and Reduction
    PAN Guanghong, MENG Ming*, LI Xingang
    2011, 32 (1):  135-138.  DOI: 10.3724/SP.J.1088.2010.00732
    Abstract ( 2475 )   [Full Text(HTML)] () PDF (605KB) ( 957 )  
    A series of B-site Fe-substituted defected perovskite BaCo1-xFexO3-δ catalyst samples for NOx storage and reduction were prepared. The NOx storage and sulfur-resistance performance were investigated. N2 adsorption-desorption, X-ray diffraction, Infrared spectroscopy, temperature-programmed reduction, and temperature-programmed desorption were employed for structural characterization. Fe-substitution can increase the sulfur resistance ability of BaCoO3 perovskite. Among the Fe-substituted samples, the one with x = 0.4 shows the largest NOx storage capacity (NSC). After deep sulfation it still possesses higher NSC (398 μmol/g), showing strong sulfur resisting ability. The mobility of surface lattice oxygen and the amount of surface oxygen vacancies are highly related to the properties of the catalyst. The NOx is mainly stored as ionic nitrate and monodentate nitrate species in the catalyst.
    Preparation of Cu-Zn-Al Bifunctional Catalyst by Sol-Gel Method with the Assistance of PEG and Its Catalytic Performance
    FAN Jinchuan1, HUANG Wei2,*, WU Shijian1
    2011, 32 (1):  139-143.  DOI: 10.3724/SP.J.1088.2010.00649
    Abstract ( 2705 )   [Full Text(HTML)] () PDF (525KB) ( 1321 )  
    A series of Cu-Zn-Al catalyst samples were prepared by sol-gel method with the assistance of polyethylene glycol (PEG) additive. The effect of PEG dosage on their physical and chemical properties was characterized by X-ray diffraction, N2 adsorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The catalytic performance of the catalyst for direct dimethyl ether (DME) synthesis from syngas was evaluated in a slurry reactor. The results showed that PEG can improve the texture and surface physical and chemical properties of the catalyst and therefore enhance its catalytic activity. With the increase of PEG dosage, the specific surface area, pore volume, and pore diameter of the catalyst increased, whereas the reduction temperature decreased first and then increased, and the dispersion of active component, surface Cu content, and strong acid amount first increased and then decreased. However, adding PEG can only enhance catalytic activity and selectivity of the catalyst, but has no effect on the catalyst stability.
    Efficient Vapor-Phase Synthesis of 1-Phenylazepane from Aniline and 1,6-Hexanediol over CoO/SiO2-Al2O3 Catalyst
    LIU Xinghai, ZHU Haiyan, SHI Lei*, SUN Qi
    2011, 32 (1):  144-148.  DOI: 10.3724/SP.J.1088.2010.00744
    Abstract ( 3070 )   [Full Text(HTML)] () PDF (521KB) ( 910 )  
    Vapor-phase catalytic synthesis of 1-phenylazepane from aniline and 1,6-hexanediol over CoO/SiO2-Al2O3 catalyst was investigated and the catalyst samples were characterized by N2 adsorption-desorption, X-ray diffraction, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The results indicated that the CoO/SiO2-Al2O3 catalyst showed higher activity and selectivity. When CoO loading was 0.3 mmol/g and the catalyst precursor was calcined at 700 °C (2.8 °C/min) for 4 h followed by reduction in situ at 325 °C for 2 h in the mixture gas of 50% H2-50% N2 (60 ml/min) before reaction, the yield of 1-phenylazepane could be up to 80%. The catalyst with larger specific surface area, higher dispersion of the active component, and weaker acidity favored the synthesis of the target product.
    Structure and Anti-carbon Capacity of ZrO2-Al2O3 Mixed Oxides in Ni-Based Catalyst for CH4/CO2 Reforming
    LIU Xinmei*, GAO Xiao, LI Xiang
    2011, 32 (1):  149-154.  DOI: 10.3724/SP.J.1088.2010.00726
    Abstract ( 2905 )   [Full Text(HTML)] () PDF (671KB) ( 1150 )  
    In the presence of P123 surfactant, mesoporous ZrO2-Al2O3 mixed oxides were prepared using inorganic salts as precursors by a bihydrolysis route. The results showed that the mixed oxides bear high surface area and controlling pore structure. Some solid solution can be formed througth the incorporation of zirconium to the alumina framework. The introduction of a proper amount of zirconia to alumina increased the acid sites number and acidic strength of the mixed oxides as compared with pure alumina.  Methane reforming with CO2 was used to detect the activity and stability of the Ni-based catalysts. The Ni/ZrO2-Al2O3 catalysts exhibit higher anti-carbon capacity than Ni/Al2O3, but possess slightly low activity. The improvement of anti-carbon capacity is ascribed to the dispersion of the active component and support effect induced by deficiencies and fine crystal size of the support.
    Enantioselective Hydrogenation of α-Ketoesters on Mesoporous Matrix Supported Platinum Catalysts
    CHEN Zhijian, LI Xiaohong, LI Can*
    2011, 32 (1):  155-161.  DOI: 10.3724/SP.J.1088.2011.00921
    Abstract ( 3045 )   [Full Text(HTML)] () PDF (736KB) ( 1078 )  
    The asymmetric hydrogenation of ethyl 2-oxo-4-phenyl-butyrate (EOPB) over the Pt catalysts modified by cinchonidine using mesoporous SBA-15, cubic mesoporous silica, and Al2O3 modified cubic mesoporous silica as matrix was studied. The results showed that in the channels of mesoporous SBA-15, the enantioselectivity and conversion are enhanced in larger sized channels compared to those of the hydrogenation in smaller sized channels. When the channel size of SBA-15 increases from 6.2 nm to 7.6 nm and to 9.2 nm, the hydrogenation ee is 22.0%, 36.0%, and 50.0%, respectively. The ee (53.8%) on the cubic mesoporous silica support is obviously higher than that (36.0%) on the SBA-15 support with similar channel size, and the ee on the Al2O3 modified cubic mesoporous silica support reaches 79.3%. These facts showed that the mass transfer or steric clash has important impacts on the enantioselectivity and conversion of the enantioselective hydrogenation of EOPB. In the enantioselective hydrogenation of ethyl pyruvate, the Al2O3-grafted cubic mesoporous silica supported Pt catalyst exhibits high activity and excellent enantioselectivity (ee over 90.2%), which is comparable to that of the best commercial Pt/Al2O3 catalysts. The high catalytic performance is attributed not only to the developed cubic channel structure of the Pt catalyst support, but also to the enhancement of the interaction of Pt nanoparticles and the Al2O3-grafted support, which would improve the modification of cinchonidine on the surface of Pt particles. These indicate that the Al2O3 modified cubic mesoporous silica is a novel, promising support material for the heterogeneous chiral catalysis.
    Oxa-Michael Addition Catalyzed by Amide-Based Acidic Ionic Liquids
    GUO Hui, WANG Junliang, LI Xia, Lü Deshui, LIN Xianfu*
    2011, 32 (1):  162-165.  DOI: 10.3724/SP.J.1088.2011.00531
    Abstract ( 4225 )   [Full Text(HTML)] () PDF (460KB) ( 1200 )  
    A series of acidic ionic liquids, including N-methyl-2-pyrrolidonium dihydrogen phosphate ([NMPH]H2PO4), caprolactam dihydrogen phosphate ([NHCH]H2PO4), N,N′-dimethylformamide dihydrogen phosphate ([DMFH]H2PO4), and N,N′-dimethylacetamide dihydrogen phosphate ([DMEH]H2PO4), were synthesized and characterized. Oxa-Michael addition of β-phenylethanol to methyl vinyl ketone (MVK) was used as a model reaction. The effects of cation structure, ionic liquid amount, β-phenylethanol/MVK ratio, reaction temperature, and reaction time were measured. Under the optimized conditions of n(β-phenylethanol):n(MVK) = 1:2, 25 °C, 24 h and using [NMPH]H2PO4 as catalyst, the β-phenylethanol conversion was 95%. The ionic liquid was stable and could be reused at least 5 times with a slight loss of activity. All the amide-based acidic ionic liquids gave higher conversion compared with imidazolium acidic ionic liquid, which showed that the effect of cation structure was important. A possible reaction mechanism was proposed and the evidence for the role of amide-based acidic ionic liquids in Oxa-Michael addition was given.
    Co(III)-Modified SBA-15: Preparation, Characterization and Catalytic Performance for Epoxidation of Cyclohexene
    GAO Pengfei, ZHANG Tieming, ZHOU Yuan, ZHAO Yongxiang*
    2011, 32 (1):  166-171.  DOI: 10.3724/SP.J.1088.2010.00722
    Abstract ( 3117 )   [Full Text(HTML)] () PDF (791KB) ( 952 )  
    A Co(III)-modified mesoporous material (SBA-15-Co(III)) was prepared by supporting an in situ formed Co(III) complex on o-dicarboxylic acid modified SBA-15 (SBA-15-(COOH)2) that was synthesized by first the Diels-Alder reaction between maleic anhydride and cyclopentadienyl-modified SBA-15 (SBA-15-Cp) and then the hydrolysis of resulting anhydride. Fourier transform infrared spectroscopy, elemental analysis (ICP-AES), and X-ray photoelectron spectroscopy confirmed the successful incorporation of carboxyl and Co(III) in the mesopores. The results of X-ray powder diffraction, N2-sorption, and high resolution transmission electron microscopy showed that SBA-15-Co(III) well maintained the mesostructure of SBA-15. In the presence of isobutylaldehyde, SBA-15-Co(III) showed moderate activity and stability in the epoxidation of cyclohexene when the flow rate of O2 was 5 ml/min, the solvent was acetonitrile, the reaction temperature was 40 °C, and time was 6 h. The yield and selectivity of cyclohexene oxide could reach 58% and 63.7%, respectively. The yield and selectivity of cyclohexene oxide could still maintained 51.6% and 56.5% after six catalytic cycles.
    Preparation of Polymetallic ZSM-5 Catalysts and Their Catalytic Performance for 2,6-Lutidine Synthesis
    WEN Yanlong , ZHANG Yuecheng*, FENG Cheng, ZHANG Di , XU Weihua, ZHAO Jiquan
    2011, 32 (1):  172-178.  DOI: 10.3724/SP.J.1088.2011.00632
    Abstract ( 2987 )   [Full Text(HTML)] () PDF (525KB) ( 1013 )  
    A series of modified ZSM-5 catalysts for 2,6-lutidine synthesis through catalytic amination of acetone and methanol were prepared by a transition metal doping method. The catalyst 6%Pb-0.5%Fe-0.5%Co/ZSM-5(200) with good performance in the reaction was selected on a fixed-bed reactor. The reasons for the improvement of the catalyst performance by doping transition metals into ZSM-5 were discussed. The effects of reaction temperature, molar ratio of ammonia to methanol, composition of raw materials, and residence time on the catalytic performance of the catalyst were studied. Acetone conversion and 2,6-lutidine yield reached 67.6% and 40.3%, respectively, when the reaction was run at 450 °C for 20 h under the conditions of atmospheric pressure, the molar ratio of ammonia to acetone to methanol of 2:2:1, the volume content of water of 40%, and the residence time of 5.5 s. With the time extension, the performance of the catalyst got deterioration gradually and the yield of 2,6-lutidine dropped to 23% after a time on stream of 42 h. The catalyst activity could be recovered largely by air oxidation on line. The possible reasons for the deterioration of the catalyst performance were discussed.
    Methyl Ethyl Ketone Ammoximation over Ti-MWW in a Continuous Slurry Reactor
    ZHAO Song, XIE Wei, LIU Yueming, WU Peng*
    2011, 32 (1):  179-183.  DOI: 10.3724/SP.J.1088.2011.00735
    Abstract ( 3342 )   [Full Text(HTML)] () PDF (476KB) ( 1077 )  
    The catalytic performance of Ti-MWW/H2O2 system for the ammoximation of methyl ethyl ketone (MEK) to methyl ethyl ketone oxime (MEKO) was investigated in a continuous slurry reactor. The effects of various reaction parameters on the catalytic performance of Ti-MWW were studied in detail. Under the optimized reaction conditions, Ti-MWW showed MEK conversion and MEKO selectivity over 95% and 99%, respectively. Moreover, Ti-MWW can serve as an extremely robust catalyst, exhibiting a longer lifetime in comparison with conventional TS-1.
    Effect of Preparation Conditions of Catalyst Ink on the Electrochemical Properties of Pt/C Catalyst
    WANG Yi1, ZENG Xiang’an2, LIU Hong1, SONG Shuqin2,*
    2011, 32 (1):  184-188.  DOI: 10.3724/SP.J.1088.2011.00736
    Abstract ( 3191 )   [Full Text(HTML)] () PDF (770KB) ( 1564 )  
    The influence of the main catalyst ink preparation parameters, such as sonication dispersing time and dispersants, on the electrochemical performance of 50% Pt/C was studied and discussed. The sonication dispersion time and dispersants have obvious effects on the performance of Pt/C. The optimized sonication dispersion time is 10 min. In the case of sonication dispersion time less than 10 min, the performance is inferior because of the uncompleted dispersion of the electrocatalyst. While in the case of sonication dispersion time more than 10 min, the performance is also poor due to Pt particles agglomeration caused by the temperature increase in the catalyst ink during the sonication dispersion process. The dispersants also significantly affect the activity of Pt/C. When ethanol is adopted as the dispersant, Pt/C possesses a higher electrochemical surface area and exhibits the highest activity for oxygen reduction reaction. This could be attributed to the joint characteristics of low polarization and low viscosity of ethanol. Moreover, the lower temperature of the catalyst ink during the sonication dispersion process using ethanol as the dispersant also contributes to its desirable electrochemical results.
    Polymerization of ε-Caprolactone and Copolymerization with rac-Lactide Catalyzed by Mono(amidinate) Aluminum Complexes
    QIAN Feng, LIU Keyin, MA Haiyan*
    2011, 32 (1):  189-196.  DOI: 10.3724/SP.J.1088.2011.00739
    Abstract ( 2793 )   [Full Text(HTML)] () PDF (552KB) ( 838 )  
    Mono(amidinate) aluminum complexes showed high catalytic activity for the ring-opening polymerization of ε-caprolactone in toluene at ambient temperature. Monomer conversion up to 91% could be reached within 1 h when using [{PhC(N-2,6-iPr2C6H3)2}AlMe2] (C1) as initiator at 25 ºC. The electron-donating groups on the ortho-positions of the N-substituted phenyl ring were superior to the electron-withdrawing groups for the enhancement of the catalytic activity, but both brought an increase in activity when compared with the un-substituted complex C7. The complexes bearing two ortho-substitutents on one of the N-phenyl rings were more active than the analogues bearing one ortho-substitutent. Although high molecular weight poly(ε-caprolactone)s were obtained by using these aluminum catalysts, the polymerization of ε-caprolactone was not well controlled as indicated by the broad molecular weight distributions (PDI = 1.43~1.85) and the deviation of the number average molecular weight from the theoretical values. Sequential copolymerization of ε-caprolactone and rac-lactide using mono(amidinate) aluminum complexes afforded poly(ε-caprolactone)-poly(rac-lactide) diblock copolymer, which was characterized well by NMR spectroscopy and gel permeation chromatography analysis.