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    Chinese Journal of Catalysis
    2012, Vol. 33, No. 5
    Online: 09 May 2012

    Cover:

    Zhang and Lü in their review on pages 745–756 summarized transition metal-catalyzed reactions for the synthesis of carboxylic acid and derivatives using CO2 to carboxylate carbon nucleophiles and C–H bonds and via the reaction of CO2 with unsaturated organic compounds (especially those with a carbon–carbon multiple bond).

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    Table of Contents
    Table of Contents for Vol. 33 No. 5
    2012, 33 (5):  0-0. 
    Abstract ( 1252 )   PDF (1422KB) ( 715 )  
    Summary
    Synthesis of Carboxylic Acids and Derivatives Using CO2 as Carboxylative Reagent
    ZHANG Wen-Zhen, Lü Xiao-Bing
    2012, 33 (5):  745-756.  DOI: 10.1016/S1872-2067(11)60390-2
    Abstract ( 3464 )   [Full Text(HTML)] () PDF (760KB) ( 1391 )  
    The catalytic transformation of carbon dioxide into high value-added fine chemicals has attracted attention because this will make CO2 into an abundant, inexpensive, and renewable C1 feedstock. More than 20 reactions involving CO2 as a starting material have been developed in recent decades but their successful industrialization is limited. One type of reactions that is technologically viable is to use CO2 as a carboxylative reagent in the production of a wide range of carboxylic acids and derivatives. This review focused on transition metal-catalyzed reactions for the synthesis of various carboxylic acid and derivatives from CO2, by the carboxylation of carbon nucleophiles and C–H bonds and reactions of CO2 with unsaturated organic compounds (especially those with a carbon–carbon multiple bond). This review also included transition metal-free or organocatalytic reactions for the transformation of CO2 into carboxylic acid and derivatives.
    Research Progress in Supported Catalysts for Heck Reaction
    LIU Hong-Fei, JIA Zhi-Gang, JI Sheng-Fu
    2012, 33 (5):  757-767.  DOI: 10.3724/SP.J.1088.2012.20145
    Abstract ( 3000 )   [Full Text(HTML)] () PDF (1053KB) ( 1453 )  
    Heck reaction is a sort of classical C–C coupling reaction. The traditional homogeneous Heck reaction catalyst has a number of disadvantages, in particular, separated and recycled after reaction. In recent years, the supported Heck reaction catalysts have attracted wide attention owing to their high catalytic activity and excellent reusable performance. The research progress of the supported palladium-based and non-palladium-based Heck reaction catalysts was reviewed. The characteristics of catalytic active component on different supports in the performance of Heck reaction were discussed. Directions in this field for future research were suggested.
    Research Briefing
    Temperature-Programmed Methanol Conversion on a Microscale Setup Equipped with Tapered Element Oscillating Microbalance
    YUAN Cui-Yu, WEI Ying-Xu, XU Lei, LI Jin-Zhe, XU Shu-Tao, ZHOU You, CHEN Jing-Run, WANG Quan-Yi, LIU Zhong-Min
    2012, 33 (5):  768-770.  DOI: 10.3724/SP.J.1088.2012.20406
    Abstract ( 2222 )   [Full Text(HTML)] () PDF (423KB) ( 692 )  
     In combination of the real time measurement of coke deposition with tapered element oscillating microbalance and the analysis of the effluent from the fixed-bed reactor with online gas chromatography, a complete prospect of methanol conversion under the condition of programmed temperature increase was plotted.
    Research papers
    Catalytic Selective Oxidation of 4-Chlorotoluene by Bi-MCM-41
    ZHAO Jun-Li, QIAN Guang, LI Feng-Yun, ZHU Jie, JI Sheng-Fu, LI Lei
    2012, 33 (5):  771-776.  DOI: 10.1016/S1872-2067(11)60367-7
    Abstract ( 2362 )   [Full Text(HTML)] () PDF (524KB) ( 966 )  
    A series of bismuth incorporated MCM-41 mesoporous samples were synthesized and characterized by inductive coupled plasma emission spectrometer (ICP), X-ray diffraction, N2 adsorption/desorption, transmission electron microscopy, and UV-Vis spectroscopy. These samples catalyzed the selective oxidation of 4-chlorotoluene efficiently even on a large scale with H2O2 as oxidant in acetonitrile. No bismuth was detected by ICP in the condensed reaction mother liquid, and the recycle test proved the catalyst was stable.
    Graphene-TiO2 Composite Photocatalyst with Enhanced Photocatalytic Performance
    ZHAO Hui-Min, SU Fang, FAN Xin-Fei, YU Hong-Tao, WU Dan, QUAN Xie
    2012, 33 (5):  777-782.  DOI: 10.1016/S1872-2067(11)60374-4
    Abstract ( 3835 )   [Full Text(HTML)] () PDF (518KB) ( 1368 )  
    Here we used a hydrothermal process and calcination in the absence of O2 to obtain a highly efficient chemically bonded graphene-TiO2 nanocomposite photocatalyst utilizing graphene oxide and tetra-n-butyl titanate as precursors. The nanocomposite photocatalyst could inhibit the recombination of photo-generated electron-hole pairs of TiO2 and then enhanced the photocatalytic efficiency. The results presented by transmission electron microscope, X-ray diffraction, Raman microscopy, and X-ray photoelectron spectroscopy showed that anatase TiO2 particles attached on the surface of the film-shaped graphene. The photocatalytic capability of graphene-TiO2 catalyst under UV light was evaluated and the results showed that graphene-TiO2 had good stability and better photocatalytic ability than pure TiO2 prepared by similar method. The holes governed the photocatalytic process and the photocatalytic performance of this photocatalyst was improved at high pH value.
    Cold Plasma-Assisted Selective Catalytic Reduction of NO over B2O3/γ-Al2O3
    YU Qin-Qin, LIU Tong, WANG Hui, XIAO Li-Ping, CHEN Min, JIANG Xiao-Yuan, ZHENG Xiao-Ming
    2012, 33 (5):  783-789.  DOI: 10.1016/S1872-2067(11)60362-8
    Abstract ( 2730 )   [Full Text(HTML)] () PDF (492KB) ( 1872 )  
    A plasma-assisted catalytic system for the selective catalytic reduction of NO with methane was investigated. NO2, HCHO, CH3NO, and CH3NO2 were the reactive intermediates generated by the plasma. The further reactions of these intermediates on the catalyst during the thermal catalytic stage resulted in the conversion of NOx to N2, which was verified by temperature-programmed surface reaction characterization. B2O3/γ-Al2O3 was the best catalyst with the maximum conversion of NOx to N2 increasing from 33.4% on γ-Al2O3 to 51.0% on 10 wt% B2O3/γ-Al2O3 at 300 oC. NH3-TPD characterization showed that the acidity of the catalyst is important for the reduction of NOx by the intermediates generated by the plasma. NOx-TPD showed that the adsorbed NOx species on the catalysts also played a role in the conversion of NOx.
    Comparison of Ni2P/SiO2 and Ni/SiO2 for Hydrogenolysis of Glycerol: A Consideration of Factors Influencing Catalyst Activity and Product Selectivity
    HUANG Jin-Hua, CHEN Ji-Xiang
    2012, 33 (5):  790-796.  DOI: 10.1016/S1872-2067(11)60375-6
    Abstract ( 2872 )   [Full Text(HTML)] () PDF (462KB) ( 974 )  
    Ni2P/SiO2 and Ni/SiO2 catalysts were prepared for the hydrogenolysis of glycerol, and their structural properties were characterized by N2 sorption, X-ray diffraction, X-ray fluorescence, CO chemisorption, H2 temperature-programmed desorption, and NH3 temperature-programmed desorption. It was found that Ni2P/SiO2 had a similar density of exposed Ni sites as Ni/SiO2, while Ni2P/SiO2 had much larger amount of acid sites and surface hydrogen species than Ni/SiO2. Ni2P/SiO2 was more active than Ni/SiO2 in the hydrogenolysis of glycerol. This is attributed to the synergism between acid and metal sites on Ni2P/SiO2. Glycerol was mainly converted to 1,2-propanediol over Ni2P/SiO2, while it was mostly converted to not only 1,2-propanediol but also ethylene glycol and ethanol over Ni/SiO2. The formation of ethylene glycol and ethanol on Ni/SiO2 is attributed to the C–C bond cleavage catalyzed by metallic Ni rather than weak acidity. In addition, temperature and H2 pressure increase did not promote the formation of ethylene glycol and ethanol on Ni2P/SiO2. Instead they mainly promoted the further conversion of 1,2-propanediol to form 1-propanol. Thus, Ni2P/SiO2 was more active for the cleavage of C–O bonds and less active for the cleavage of C–C bonds than Ni/SiO2. We suggest that the higher activity of Ni2P/SiO2 for the cleavage of C–O bonds can be ascribed to its acidity, while its lower activity for the cleavage of C–C bonds may be mainly related to its electronic and geometrical properties.
    Effect of Partial Substitution of Ni by Cu in LaNiO3 Perovskite Catalyst for Dry Methane Reforming
    G. R. MORADI*, F. KHOSRAVIAN, M. RAHMANZADEH
    2012, 33 (5):  797-801.  DOI: 10.1016/S1872-2067(11)60378-1
    Abstract ( 2488 )   [Full Text(HTML)] () PDF (361KB) ( 1155 )  
    A series of ternary perovskite type oxides LaNi1-xCuxO3 (x = 0.2, 0.4, 0.6, 0.8, and 1.0) were synthesized via the sol-gel method in propionic acid. Partial substitution of Ni by Cu showed higher activities and selectivities towards syngas products. LaNi0.8Cu0.2O3 was the most active toward the CH4 and CO2 conversions, and was selective for syngas products. Temperature-programmed reduction results showed that the addition of Cu facilitates the reduction of Ni3+ to Ni0, which is the main reason for the higher performance of this catalyst.
    Preparation and Photocatalytic Properties of Cu2S/Tetrapod-Like ZnO Whisker Nanocomposites
    WU De-Zhi, FAN Xi-Mei, DAI Jia, LIU Hua-Rong, LIU Hong, ZHANG Feng-Zhang
    2012, 33 (5):  802-807.  DOI: 10.1016/S1872-2067(11)60380-X
    Abstract ( 3152 )   [Full Text(HTML)] () PDF (555KB) ( 920 )  
    Nanocomposites of tetrapod-like ZnO whisker (T-ZnOw) with loaded Cu2S were synthesized with different Cu/Zn molar ratios with the assistant of poly(vinyl pyrrolidone) (PVP) by the polyol process. The composite samples were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy. The photocatalytic activities for the Cu2S/T-ZnOw nanocomposites increased with Cu/Zn molar ratio up to 4%, and then decreased with further increase of the Cu/Zn molar ratio up to 10%. The Cu2S/T-ZnOw nanocomposites exhibited higher activity than T-ZnOw for the photocatalytic degradation of methyl orange. Recycling experiments were also performed. The photocatalytic activity of the photocatalyst showed no decrease after three cycles, which demonstrated that the Cu2S/T-ZnOw photocatalyst had excellent stability.
    Effects of Li Promoter on the Performance of Co/AC Catalysts for CO Hydrogenation to Mixed Linear α-Alcohols
    PEI Yan-Peng, DING Yun-Jie, ZANG Juan, SONG Xian-Gen, DONG Wen-Da, ZHU He-Jun, WANG Tao, CHEN Wei-Miao
    2012, 33 (5):  808-812.  DOI: 10.3724/SP.J.1088.2012.10917
    Abstract ( 2204 )   [Full Text(HTML)] () PDF (617KB) ( 983 )  
    The effect of Li promoter on the catalytic performance of the activated carbon (AC) supported cobalt catalysts (Co/AC) for CO hydrogenation was investigated by means of CO hydrogenation, X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), and temperature-programmed desorption of adsorbed CO (CO-TPD). The results showed that the addition of Li significantly suppressed the formation of gaseous hydrocarbons and remarkably improved the selectivities for higher hydrocarbons (C5+) and mixed linear α-alcohols (C1–C18) of CO hydrogenation over the Co/AC catalyst. However, the activity of CO hydrogenation decreased gradually with the increase of Li loading in the Co-based catalyst. H2-TPR and CO-TPD results illuminated that the existence of Li decreased the reducibility of Co2+ and the ability of CO dissociation, which was the rate-determining step. XRD results indicated that the existence of Li promoter enhanced the formation of Co2C species.
    One-Step Oxidation of Methanol to Dimethoxymethane on V2O5/CeO2 Catalyst
    GUO He-Qin, LI De-Bao, CHEN Cong-Biao, FAN Zhi-Hong, SUN Yu-Han
    2012, 33 (5):  813-818.  DOI: 10.3724/SP.J.1088.2012.11015
    Abstract ( 2590 )   [Full Text(HTML)] () PDF (575KB) ( 753 )  
    The V2O5/CeO2 catalyst samples were prepared by the sol-gel method and applied in the methanol partly oxidation. The influence of V2O5 content on the existing state of vanadia and surface properties as well as the catalytic performance was studied. The results showed that the vanadia was monolayer dispersed with V2O5 content was 15%, aggregated as V2O5 crystalline with above 20%, and formed CeVO4 with 30%. The higher dispersion of vanadia can lead to stronger reducibility and more acidic sites, which were closely related to the higher methanol conversion and dimethoxymethane selectivity.
    Preparation and Properties of Pt/ZrxTi1-xO2 Catalysts with Low-Level SO2 Oxidation Activity for Diesel Oxidation
    YANG Zheng-Zheng, CHEN Yong-Dong, ZHAO Ming, ZHOU Ju-Fa, GONG Mao-Chu, CHEN Yao-Qiang
    2012, 33 (5):  819-826.  DOI: 10.3724/SP.J.1088.2012.11108
    Abstract ( 2704 )   [Full Text(HTML)] () PDF (605KB) ( 804 )  
    A series of ZrxTi1-xO2 (x = 0, 0.1, 0.5, 0.9, 1.0) mixed oxides were prepared by the co-precipitation method and were used as supports to prepare Pt/ZrxTi1-xO2 catalysts by impregnation with H2PtCl6 solution. The catalysts were characterized by N2 adsorption, X-ray diffraction-desorption, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The results indicated that the dominative crystalline phase of Zr0.1Ti0.9O2 is anatase and it has higher specific surface area (94 m2/g) and larger pore volume (0.33 cm3/g). Compared with the Pt/ZrxTi1-xO2 (x = 0, 0.5, 0.9, 1.0) catalysts, Pt/Zr0.1Ti0.9O2 shows excellent catalytic activity (T50 of HC and CO are 185 and 174 oC, respectively, and T90 of HC and CO are 197 and 201 oC, respectively) and low-level oxidation activity of SO2 (the SO2 conversion at 350 oC is only 25.5%).
    Preparation and Application of SO42–/SnO2/SBA-15 Solid Acid Catalyst for Acetalization of Cyclic Ketones
    YANG Zhi-Wang, HONG Wei, WANG Jia, CHEN Li-Na, JIA Na, ZHAO Lei, MA Heng-Chang, LEI Zi-Qiang
    2012, 33 (5):  827-832.  DOI: 10.3724/SP.J.1088.2012.11104
    Abstract ( 2394 )   [Full Text(HTML)] () PDF (1003KB) ( 1148 )  
    SO42/SnO2/SBA-15 catalyst samples with different amounts of SnO2 were prepared by a wetness impregnation method and characterized by X-ray diffraction, N2 adsorption-desorption, and transmission electron microscopy. Their catalytic performance for the acetalization of 4-tert-butylcyclohexanone with glycol was investigated. The results showed that SBA-15 supported SO42/SnO2 improved the catalytic activity markedly, which was caused by the increasing surface area of the sulfated tin oxide. The catalytic performance of SO42/20%SnO2/SBA-15 for acetalization of several cyclic ketones with diols was also explored. Under the optimum conditions, a series of cyclic ketones such as cyclohexanone, 4-methylcyclohexanone, and 4-tert-butylcyclohexanone were well transformed into the corresponding products. The catalyst can be reused for several times without any significant loss in catalytic activity.
    Preparation and Characterization of Metal-Organic Framework Supported Gold Catalysts and Their Catalytic Performance for Three-Component Coupling Reaction
    LIU Li-Li, ZHANG Xin, GAO Jin-Sen, XU Chun-Ming
    2012, 33 (5):  833-841.  DOI: 10.3724/SP.J.1088.2012.11112
    Abstract ( 2939 )   [Full Text(HTML)] () PDF (992KB) ( 1829 )  
    IRMOF-3-SI-Au(PS) and IRMOF-3-SI-Au(OP) catalysts were synthesized by post-synthesis method (PS) and one-pot method (OP), respectively. The catalysts were characterized by X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and differential thermal, transmission electron microscopy, and temperature-programmed reduction. These two catalysts were tested by three-component coupling reaction of aldehydes, alkynes, and amines. The substrate scope, catalyst reusability, and possible mechanism were investigated. Both two catalysts showed higher conversions of benzaldehyde and 100% selectivity for propargylamines. Compared with IRMOF-SI-Au(OP), IRMOF-SI-Au(PS) gave a higher aldehyde consumption rate at 120 oC (13.7 vs 2.0 mmol/(g·h)) based on total gold content. Both aromatic and aliphatic aldehydes including those bearing functional groups, such as alkoxy, alkyl, and chloro-group, were able to undergo the corresponding three-component-coupling. It was found that aryl aldehydes possessing electron-drawing group afforded higher conversion than that with an electron-donating group bound to the benzene ring. Among the various amines tested, alicyclic amines, such as piperidine, pyrolidine, and morpholine, gave high conversions of benzaldehyde, whereas the diethylamine afforded lower conversion of benzaldehyde. The catalysts could be reused for three reaction cycles with only slight drop in activity. A tentative mechanism was proposed involving the activation of the C–H bond of alkyne by IRMOF-3 immobilized gold catalysts.
    Cu/ZrO2 Catalyst for Low-Temperature Water-Gas Shift Reaction: Preparation, Characterization and Performance
    RUAN Chun-Xiao, CHEN Chong-Qi, ZHANG Yan-Jie, LIN Xing-Yi, ZHAN Ying-Ying, ZHENG Qi
    2012, 33 (5):  842-849.  DOI: 10.3724/SP.J.1088.2012.11117
    Abstract ( 2284 )   [Full Text(HTML)] () PDF (806KB) ( 894 )  
    A series of Cu/ZrO2 catalyst samples with excellent catalytic performance for low-temperature water-gas shift (WGS) reaction were prepared by a two-step method. First, pure monoclinic ZrO2 support was prepared by hydrothermal synthesis, and then a certain amount of CuO was deposited on the support by deposition-precipitation. The catalyst samples were characterized by X-ray diffraction, N2-physisorption, H2 temperature-programmed reduction, X-ray fluorescence elemental analysis, high resolution transmission electron microscopy, and scanning electron microscopy, aiming to know the effect of preparation parameters on the catalytic performance of these samples. The relationship between their catalytic performance and structures was discussed. The crystalline size and dispersity of the Cu particles, texture of Cu/ZrO2 catalyst samples as well as the interaction between ZrO2 and Cu are greatly influenced by the preparation conditions, such as the CuO amount, precipitation temperature, precipitant and calcination temperature. And the optimal preparation parameters are ZrO2 loaded with 25% CuO, precipitation at 65 oC with KOH as precipitant, and calcination at 300 oC for 2 h purging with H2.
    Synthesis, Characterization and Photocatalytic Performance of CdS/TiO2 Nanotube photocatalyst
    ZHOU Qiang, YUAN Bao-Ling, XU Dong-Xing, FU Ming-Lai
    2012, 33 (5):  850-856.  DOI: 10.3724/SP.J.1088.2012.11214
    Abstract ( 2787 )   [Full Text(HTML)] () PDF (1321KB) ( 1310 )  
    A typical hydrothermal synthesis was employed to prepare titania nanotubes (TNTs) with anatase crystal structure using P25 as a raw material. The effects of hydrothermal reaction temperature, calcination temperature on the morphology and crystal structure of TNTs were investigated. CdS quantum dots (QDs) formed in situ were assembled onto the surfaces of TNTs to form CdS/TNTs nanocomposite photocatalyst by using bifunctional organic linker, thiolactic acid. The effects of thiolactic acid concentration on the loading amount of CdS QDs and photoactivity of CdS/TNTs nanocomposite were also studied. The results indicated that when the hydrothermal reaction and calcination temperatures were 150 and 400 ºC, respectively, TNTs have anatase crystal structure with following unique properties, an average diameter of about 8–10 nm, the length of several hundred nanometers with uniform inner and outer diameter along the length direction, tube wall with multilayer structure of about 2–3 nm. After modification with CdS QDs, the absorption of CdS/TNTs nanocomposite in visible light area was enhanced greatly, compared with that of TNTs. The absorption edge of CdS/TNTs was extended to 580 nm. The CdS/TNTs exhibited excellent photocatalytic performance for RhB degradation under visible light irradiation simulated by halogen tungsten lamp.
    Preparation of Immobilized Lipase through Combination of Cross-Linked Enzyme Aggregates and Biomimetic Silicification
    JIANG Yan-Jun, WANG Qi, WANG Wen-Qin, ZHOU Li-Ya, GAO Jing
    2012, 33 (5):  857-862.  DOI: 10.3724/SP.J.1088.2012.11055
    Abstract ( 2559 )   [Full Text(HTML)] () PDF (448KB) ( 1050 )  
    The hybrid biocatalyst was prepared by the combination of cross-linked enzyme aggregates (CLEAs) and biomimetic silicification, where the lipase Candida sp. 99-125 was used as model enzyme. The preparation conditions of lipase-CLEAs were optimized and the resulting activity of 771 U/g was obtained. Under the optimum conditions, 75% of the activity recovery was obtained. P/CLEAs was prepared by coprecipitation of lipase with polyethylene-imine (PEI), and the resulting activity was 897 U/g. The activity recovery of P/CLEAs was about 88%. The silica coating was formed on the outside surface of P/CLEAs via the induction of PEI. The resulting Coated-CLEAs showed high reusability. The stability of the Coated-CLEAs, including the resistance to trypsin and organic solvents, was also significantly improved.
    Synthesis of Single-Phase Iron Carbides and Their Adsorption Performance
    WANG Rui-Xue, WU Bao-Shan, LI Yong-Wang-
    2012, 33 (5):  863-869.  DOI: 10.3724/SP.J.1088.2012.11204
    Abstract ( 2815 )   [Full Text(HTML)] () PDF (586KB) ( 1488 )  
    A series of iron carbides with single-phases, including ε-Fe2C, χ''-Fe5C2, and θ-Fe3C, were synthesized in different carbonization gases either in higher or lower CO part pressure. After passivation, the iron carbides were characterized by N2 physical adsorption, Mössbauer spectroscopy, temperature-programmed desorption, and laser Raman spectroscopy. The effects of carbonization gases and temperature on the structure properties of the iron carbides were obvious, especially for carbonization temperature. Carbonization gas with higher CO part pressure and higher temperature both enhances the carbon deposition on the iron carbides surface. It is interesting to note that the carbon deposition increases firstly with the rise of temperature and then decreases. The differences in structure and carbon deposition on iron carbides result in varied adsorption properties. Fe2C synthesized at lower temperature (200 oC) was highly susceptible to dissociative adsorption of CO on its surface, while Fe3C prepared under lower CO part pressure showed the highest desorption of adsorbed CO. The ability of dissociative adsorption of CO on the iron carbides prepared under other condition reduces probably because of carbon deposition.
    Superfine Fe-V-O Catalyst for Liquid-Phase Oxidation of Toluene to Benzaldehyde
    ZHANG Gui-Quan, ZHANG Xin, QI Min, LIN Tao, GONG Ting
    2012, 33 (5):  870-877.  DOI: 10.3724/SP.J.1088.2012.11010
    Abstract ( 2234 )   [Full Text(HTML)] () PDF (672KB) ( 750 )  
    Iron-vanadium oxide catalyst (Fe-V-O) samples were prepared by co-precipitation, gel combustion, and hydrothermal method, respectively. The catalytic activity of the as-prepared catalyst in the liquid-phase oxidation of toluene by hydrogen peroxide was tested. In addition, the physicochemical properties of these samples were characterized by N2 adsorption-desorption, powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and H2 temperature-programmed reduction. The preparation method significantly affected the structure, specific surface area, morphology, surface V/Fe ratio and reducibility of the as-prepared catalyst samples. Fe-V-O sample prepared by hydrothermal method exhibited the highest benzaldehyde yield and better reusability compared with other investigated samples, due to its smaller particle size, larger specific surface area, higher V/Fe surface ratio and the moderate reducibility.
    Preparation and Characterization of Silica-Supported Imine Palladacycle Complex and Its Catalytic Performance
    YANG Xin-Li, ZHANG Cheng-Jun, DAI Wei-Lin, LIU Jian-Ping, WEI Mei-Sheng
    2012, 33 (5):  878-884.  DOI: 10.3724/SP.J.1088.2012.11139
    Abstract ( 2411 )   [Full Text(HTML)] () PDF (518KB) ( 930 )  
    The silica-supported imine palladacycle complex was synthesized by the following procedure as, first, NH2-modified silica was obtained by grafting with organosilane; second, the as-obtained silica compound was treated with o-methoxybenzaldehyde to form SiO2-NH2-Schiff base; at last, the catalyst was attained after being reacted with Li2PdCl4-methanol solution. The as-prepared complex was characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy techniques. The catalytic activity test was carried out in Heck reaction of iodobenzene with acrylamide to the trans-cinnamamide. The effect of reaction parameters on the product yield was investigated, such as solvent, reaction temperature, molar ratio of iodobenzene to acrylamide, kinds and amount of base, amount of catalyst, and reaction time. The optimum reaction conditions were established and the possible reaction mechanism was discussed.
    Catalytic Oxidation of Benzyl Alcohol by Dioxygen over Bidentate Schiff Base-Type Oxovanadium(IV) Complex Immobilized on Crosslinked Polystyrene Microspheres
    DAI Xin, GAO Bao-Jiao, LEI Hai-Bo
    2012, 33 (5):  885-890.  DOI: 10.3724/SP.J.1088.2012.11129
    Abstract ( 2312 )   [Full Text(HTML)] () PDF (714KB) ( 870 )  
    The reaction between salicylaldehyde (SA) and aminomethyl (AM) group-modified crosslinked polystyrene (CPS) microspheres was allowed to be carried out, resulting in the SAAM-CPS microspheres, on which bidentate Schiff base-type oxovanadium(IV) complex was immobilized. Subsequently, the coordination reaction between SAAM-CPS microspheres and vanadyl sulfate was performed, obtaining Schiff base-type oxovanadium(IV) complex immobilized on the CPS-[VO(SAAM)2] microspheres, namely achieving the heterogeneous oxovanadium(IV) complex catalyst. The CPS-[VO(SAAM)2] microspheres were characterized by Fourier transform infrared, scanning electron microscope, and thermal gravimetric analysis. The complex catalyst was used in the oxidation of benzyl alcohol by dioxygen and the catalytic activity was examined. The experimental results show that, through the coordination reaction between SAAM-CPS microspheres and vanadyl sulfate, the immobilized Schiff base-type oxovanadium(IV) complex can be successfully prepared. In the oxidation of benzyl alcohol by dioxygen, the heterogeneous oxovanadium(IV) complex catalyst CPS-[VO(SAAM)2] has very high catalytic activity and excellent selectivity. Under the mild conditions such as at ordinary pressure of dioxygen and at a lower temperature of 90 oC, benzyl alcohol can be transformed to benzaldehyde as a single product with yield of 80%. The solvent porlarity affects the catalytic activity of the catalyst greatly. The stronger the solvent polarity, the higher the catalyst activity is and the higher the benzaldehyde yield is. The CPS-[VO(SAAM)2] catalyst has excellent reusability.
    Immobilization of Cinchona Quaternary Ammonium Salts as the Chiral Phase Transfer Catalysts on Multi-walled Carbon Nanotubes and Their Application in Enantioselective Alkylation
    LIU Jian, LIU , SHI Xin, YANG Qi-Hua
    2012, 33 (5):  891-897.  DOI: 10.3724/SP.J.1088.2012.11213
    Abstract ( 2211 )   [Full Text(HTML)] () PDF (397KB) ( 577 )  
    The pyrene-tagged cinchona quaternary ammonium salt, the chiral phase transfer catalysts (PTC-1), was synthesized and immobilized on multi-walled carbon nanotubes (MWCNTs). The new catalysts (PTC-1/MWCNTs) were employed in enantioselective alkylation of N-(diphenylmethyene)glycine tert-butyl ester. UV-Vis absorption spectra show the effect of different organic solvents on the adsorption and desorption of PTC-1 onto and from MWCNTs, respectively. The results show that 5.3 mg PTC-1 can be loaded on 10 mg MWCNTs in toluene, and 0.02025 mg PTC-1 was desorbed from 12.7 mg PTC-1/MWCNTs when washed by CHCl3. In the enantioselective alkylation of different halohydrocarbons with N-(diphenylmethyene)glycine tert-butyl ester using PTC-1/MWCNTs as a catalyst, the alkylating products were obtained with high yield and ee value. Furthermore, PTC-1/MWCNTs catalyst can be recovered and used repeatedly. PTC-1/MWCNTs as a new catalyst is effective in enantioselective alkylation of multiple halohydrocarbon.
    Preparation and Characterization of Sn-β Zeolites by a Two-Step Postsynthesis Method and Their Catalytic Performance for Baeyer-Villiger Oxidation of Cyclohexanone
    KANG Zi-Hua, LIU Hai-鸥, ZHANG Xiong-Fu
    2012, 33 (5):  898-904.  DOI: 10.3724/SP.J.1088.2012.11201
    Abstract ( 2816 )   [Full Text(HTML)] () PDF (887KB) ( 960 )  
    A Sn-β zeolite was prepared by a two-step postsynthesis method. The procedure consists of first creating vacant T-sites with associated silanol groups by dealumination of Al-β zeolite with nitric acid and then impregnating the resulting Si-β zeolite with an aqueous solution of SnCl4·5H2O, followed by calcination at varying temperatures. The effects of the amount of vacant T-sites, SiO2/Al2O3 ratio of Al-β zeolite and calcination temperature on the formation of the Sn-β zeolites and their catalytic performances for Baeyer-Villiger oxidation of cyclohexanone were investigated. The structure of the catalysts was characterized by X-ray diffraction, infrared spectroscopy, UV-Vis spectrophotometry, scanning electron microscopy, X-ray fluorescence spectrometry and inductively coupled plasma atomic emission spectrometry. The results show that, the Sn-β zeolite has been synthesized using a two-step postsynthesis method, and the Sn4+ ions are incorporated in the framework of the zeolite in a tetrahedral environment. The synthesized Sn-β zeolite shows impressive catalytic performance in Baeyer-Villiger oxidation of cyclohexanone using hydrogen peroxide as an oxidant.