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Chinese Journal of Catalysis
2012, Vol. 33, No. 3
Online: 15 March 2012


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Professor Gong and coworkers in their article on pages 407–415 describe a DFT study regarding reaction mechanism of selective oxidation of ethanol on atomic oxygen pre-covered Au(111) surface. Major reaction steps contain the oxidation of ethanol to acetaldehyde, coupling of ethanol to ethyl acetate, and deep oxidation of acetaldehyde to acetic acid.

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Table of Contents for Vol. 33 No. 3 2012, 33 (3):  0-0.  Abstract ( 1282 )   PDF (2501KB) ( 910 )

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Preparation and Application of Nanometer Materials Supported Ruthenium Catalysts WANG Zi-Qing, ZHANG Liu-Ming, LIN Jian-Xin, WANG Rong, WEI Ke-Mei 2012, 33 (3):  377-388.  DOI: 10.3724/SP.J.1088.2012.11046 Abstract ( 3913 )   [Full Text(HTML)] () PDF (573KB) ( 2188 )   Ru-based catalysts have many unique properties, especially under mild conditions such as law temperature and pressure. The recent developments of preparation methods and application of nanometer materials supported ruthenium catalysts were reviewed. The effects of support materials, precursors, and ruthenium nanometer particles on the performance of ruthenium catalysts were briefly summarized. Then the new preparation techniques and new progress of traditional preparation techniques were introduced systematically, and the shortages of some methods were discussed. Finally, the important application areas and catalytic performance of Ru-based supported catalysts were discussed. The development trends of Ru-based catalysts were also proposed.

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Effect of Phospholipids on the Catalytic Performance of Lipase LI Yang, DU Wei, LIU De-Hua 2012, 33 (3):  389-395.  DOI: 10.3724/SP.J.1088.2012.11043 Abstract ( 2582 )   [Full Text(HTML)] () PDF (478KB) ( 1185 )   Lipase-catalyzed acylating reaction of renewable oils for the production of various valuable chemicals has drawn considerable attention in recent years. However, natural raw oil usually contains some phospholipids. Many studies have revealed the remarkable effect of the phospholipids on lipase’s catalytic activity, thermal stability and reaction kinetics. The major phospholipid molecules contained in oils were introduced. The effect of phospholipids on enzyme’s catalytic performance as well as the related influence mechanism was reviewed during the reactions of lipase-mediated hydrolysis, esterification, and transesterification.

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Ozone Catalytic Oxidation of HCHO in Air over MnOx at Room Temperature ZHAO De-Zhi, DING Tian-Ying, LI Xiao-Song, LIU Jing-Lin, SHI Chuan, ZHU Ai-Min 2012, 33 (3):  396-401.  DOI: 10.1016/S1872-2067(11)60360-4 Abstract ( 2776 )   [Full Text(HTML)] () PDF (523KB) ( 1231 )   The complete oxidation of HCHO in air with O3 over MnOx catalysts at room temperature was studied. The MnOx catalysts were prepared by a redox method. The catalysts showed amorphous patterns in X-ray diffraction characterization. Formaldehyde in simulated air containing 137 mg/m3 HCHO with 56% relative humidity (RH, 25 oC) was totally oxidized to CO2 by 642 mg/m3 O3 over the MnOx catalysts at GHSV (gas hourly space velocity) = 2 × 105 h-1. The formaldehyde conversion and CO2 selectivity were maintained at ~ 100% during 150 min time-on-stream. The effect of the molar ratio of O3 to HCHO was also investigated. At a O3 to HCHO molar ratio of 2:3, which was significantly lower than the stoichiometric ratio, a CO2 selectivity of 100% was still achieved. No byproduct was detected during HCHO oxidation with O3 over the MnOx catalysts using an online Fourier transform infrared spectrometer.

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Rh Nanoparticles Catalyzed Hydroformylation of Olefins in a Thermoregulated Ionic Liquid/Organic Biphasic System ZENG Yan, WANG Yan-Hua, XU Yi-Cheng, SONG Ying, ZHAO Jia-Qi, JIANG Jing-Yang, JIN Zi-Lin 2012, 33 (3):  402-406.  DOI: 10.1016/S1872-2067(11)60371-9 Abstract ( 2710 )   [Full Text(HTML)] () PDF (415KB) ( 792 )   Rh nanoparticles were investigated as a catalyst for hydroformylation of olefins in thermoregulated ionic liquid/organic biphasic systems composed of an ionic liquid, namely [CH3(OCH2CH2)16N+Et3][CH3SO3−] (ILPEG750), and an organic solvent. This enables not only a homogeneous reaction but also easy biphasic separation. Under the optimized reaction conditions, the conversion of 1-octene and yield of aldehyde were 99% and 91%, respectively. The catalyst was easily separated from the product by phase separation and used eight times without evident loss of activity.

Research papers

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Mechanistic Insights into Selective Oxidation of Ethanol on Au(111): A DFT Study MENG Qing-Sen, SHEN Yong-Li, XU Jing, GONG Jin-Long 2012, 33 (3):  407-415.  DOI: 10.1016/S1872-2067(11)60340-9 Abstract ( 3530 )   [Full Text(HTML)] () PDF (740KB) ( 938 )   The reaction mechanism of selective oxidation of ethanol on Au(111) covered with atomic oxygen was described employing density functional theory calculations. The first step, dissociation of the O–H bond in ethanol, has lower barrier for transfer of the H to adsorbed oxygen or surface hydroxyl than to gold with a barrier of 0.20 or 0.17 eV, respectively. The two lower activation energies for the β-H elimination of ethoxyl, 0.29 and 0.27 eV, come from transfer of H atom to surface O atom or another ethoxyl. Ethyl acetate is formed through the β-H elimination of ethoxy hemiacetal. The formation of acetic acid is not facile through the reaction between the surface hydroxyl and acetaldehyde or between the surface oxygen and acetaldehyde at low temperature due to a high activation barrier. Except for surface oxygen and bidentate acetate, all other surface species have low diffusion barriers, suggesting that rearrangement and movement of these species from the preferred adsorption sites to the ideal configurations for reactions are facile.

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The Role of Inorganic Oxide Supports in Synthesis of Cyclic Carbonates from Carbon Dioxide and Epoxides CAO Ting, SUN Li-Ting, SHI Yu, HUA Li, ZHANG Ran, GUO Li, ZHU Wen-Wen, HOU Zhen-Shan 2012, 33 (3):  416-424.  DOI: 10.1016/S1872-2067(11)60334-3 Abstract ( 3247 )   [Full Text(HTML)] () PDF (609KB) ( 812 )   An inorganic oxide support coupled with a quaternary ammonium salt is an efficient catalyst for the cycloaddition of CO2 and epoxide to produce cyclic carbonates under relatively mild reaction conditions (90 oC, 4 MPa). When tetrabutylammonium bromide (TBAB) was used alone, the activity of the cycloaddition reaction between carbon dioxide and epoxide was only moderate. When an inorganic oxide, especially one that has abundant surface hydroxyl groups was also employed, the reaction was accelerated significantly. This demonstrated that the inorganic oxide and TBAB had a strong synergetic effect for the cycloaddition reaction. Silica was chosen as a model oxide to study the role of surface hydroxyl groups in the reaction. When the surface of silica was silylated with trimethylchlorosilane or dimethyldichlorosilane, the catalytic activity decreased sharply due to surface silylation, which indicated clearly that the surface hydroxyl groups on the silica played a decisive role in influencing the catalytic activity.

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Effect of La2O3 on Microstructure and Catalytic Performance of CuO/CeO2 Catalyst in Water-Gas Shift Reaction FANG Xing, CHEN Chong-Qi, LIN Xing-Yi-*, SHE Yu-Sheng, ZHAN Ying-Ying, ZHENG Qi 2012, 33 (3):  425-431.  DOI: 10.1016/S1872-2067(11)60337-9 Abstract ( 2742 )   [Full Text(HTML)] () PDF (532KB) ( 976 )   The water-gas shift reaction was used to evaluate a series of La2O3 modified CuO/CeO2 catalysts that were prepared by a parallel co-precipitation method. The catalytic activity and thermal stability improved significantly upon the introduction of La2O3, and CuO/CeO2-La2O3 (2 wt%) gave the highest activity and had the best thermal stability. The microstructure of the as-prepared CuO/CeO2-La2O3 catalysts and/or the CeO2-La2O3 supports was characterized by X-ray diffraction, N2 physisorption, Raman spectroscopy, and temperature-programmed reduction. The results indicate that larger specific surface areas and smaller crystal sizes of CuO and CeO2 result in improved catalytic performance for the as-prepared catalysts. Moreover, the incorporation of La3+ into the ceria lattice promotes the generation of oxygen vacancies leading to a higher number of moderate copper oxides that interact with surface oxygen vacancies on the surface of the ceria. This enhances the activity and thermal stability of the CuO/CeO2 catalyst.

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Synthesis of Polyhydroxyalkanoates by Polymerization of Methyl 3-Hydroxypropionate in the Catalysis of Lipase SONG Hao, ZHAO Yong-Jie, ZHANG Ying-Xin, KONG Wei-Bao, XIA Chun-Gu 2012, 33 (3):  432-438.  DOI: 10.1016/S1872-2067(11)60336-7 Abstract ( 2770 )   [Full Text(HTML)] () PDF (409KB) ( 754 )   The polymerization of methyl 3-hydroxypropionate as monomer catalyzed by lipase was selected as a model system in this study. The monomer with the purity around 95% could be polymerized to polyhydroxyalkanoates in the catalysis of Novozym 435. Decreasing the reaction pressure would result in the increase of product yield and high molecular weight. By choosing appropriate organic solvents, surfactants and reaction pressure, the molecular weight of polyhydroxy propionate polyester could be controlled from 1800 to 13000 (Mw value). The reusing ability of enzymatic catalyst was comparatively good. The relative activity could be maintained above 95% after 6 repeated batches reaction.

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Synthesis of 2-Substituted Benzimidazoles and 1,5-Disubstituted Benzodiazepines on Alumina and Zirconia Catalysts M. REKHA, A. HAMZA, B. R. VENUGOPAL, N. NAGARAJU 2012, 33 (3):  438-446.  DOI: 10.1016/S1872-2067(11)60338-0 Abstract ( 2890 )   [Full Text(HTML)] () PDF (443KB) ( 2572 )   In this study, alumina, zirconia, manganese oxide/alumina, and manganese oxide/zirconia have been investigated for their catalytic activity in the condensation reaction between o-phenylenediamine and an aldehyde or a ketone to synthesise 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines respectively. Surface area, surface acidity, and morphology of the catalysts have been analysed and correlated with their catalytic activity. The isolated yields of 2-substituted benzimidazoles and 1,5-disubstituted benzodiazepines are in the range of 30% to 95%. A good correlation between the amount of surface acid sites as well as the surface morphology of the catalysts and the catalytic activity has been observed. This method has been found to be simple and economical. The solid supports could be regenerated and reused without much loss in their activity. Further, the solid supports have been also found to be effective as general catalysts in the condensation of o-phenylenediamine with other substituted aldehydes and ketones.

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Effect of MgO/h-BN Composite Support on Catalytic Activity of Ba-Ru/MgO/h-BN for Ammonia Synthesis YANG Xiao-Long, TANG Li-Ping, XIA Chun-Gu, XIONG Xu-Mao, MU Xin-Yuan, HU Bin 2012, 33 (3):  447-453.  DOI: 10.1016/S1872-2067(11)60352-5 Abstract ( 2724 )   [Full Text(HTML)] () PDF (731KB) ( 1001 )   A series of MgO/hexagonal boron nitride (h-BN) composite with different mass ratio were synthesized by impregnation method and used as supports for ruthenium catalysts in ammonia synthesis reaction. The catalysts were characterized by X-ray diffraction, N2 physical adsorption, X-ray fluorescent spectrometer, scanning electron microscope, transmission electron microscope, temperature programmed reduction of H2, and temperature programmed desorption of CO2 (CO2-TPD). The activity measurements of ammonia synthesis were carried out in a fixed-bed flow reactor with a mixture of N2 and H2 atomsphere under steady-state conditions (5.0 MPa, 350–500 °C, 5000 h–1). The results showed that the rate of ammonia formation was strongly influenced by the h-BN content used in the catalysts preparation process. The Ba-Ru[1:1] (molar ratio of Ba to Ru = 1:1)/MgO/h-BN[8:2] (weight ratio of MgO to h-BN = 8:2), Ba-Ru[1:1]/MgO/h-BN[6:4] and Ba-Ru[1:1]/MgO/h-BN[5:5] catalysts exhibited higher activity than Ba-promoted Ru/MgO catalyst. At 425 °C, 5.0 MPa, flow rate of 5000 h–1, and a N2/H2 = 1/3 atmosphere, the optimum activity of 506.9 ml/(gcat·h) was achieved when MgO/h-BN[8:2] was used as the catalytic support. The execllent activity was mainly attributed to the basicity of the MgO/h-BN combination-type support, especially “weak” and “medium” basic sites. Large numbers of basic sites were observed from CO2-TPD characterization due to the interaction between MgO and the h-BN material

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Hydrothermal Deactivation of Fe-ZSM-5 Prepared by Different Methods for the Selective Catalytic Reduction of NOx with NH3 SHI Xiao-Yan, LIU Fu-Dong, DAN Wen-Po, HE Hong 2012, 33 (3):  454-464.  DOI: 10.1016/S1872-2067(11)60326-4 Abstract ( 3284 )   [Full Text(HTML)] () PDF (639KB) ( 1183 )   A series of Fe/ZSM-5 catalysts were prepared by liquid ion exchange, incipient wetness impregnation, and solid-state ion exchange to investigate the selective catalytic reduction (SCR) of NOx by NH3 (NH3-SCR). The effect of hydrothermal deactivation of Fe-ZSM-5 catalysts prepared by different methods as a function of Fe loading was investigated. Freshly made and hydrothermal aged Fe-ZSM-5 catalysts were studied through NH3-SCR activity test and characterized using X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy. Iron species on the surface of Fe-ZSM-5 catalysts were assigned to isolated Fe3+ species, oligomeric FexOy clusters, and Fe2O3 particles based on the UV-Vis spectra. The iron species distributions in the Fe-ZSM-5 catalysts prepared by these methods were quite different, which resulted in difference in SCR activity. The NH3-SCR activity of different Fe-ZSM-5 catalysts became very similar after aging, and the activity of NH3 oxidation and NO oxidation decreased with the aged catalysts. Characterization results indicated that the activity change of the aged Fe-ZSM-5 catalysts was due to the change of iron species distribution in Fe-ZSM-5 catalysts after hydrothermal aging. The relative concentration of isolated Fe3+ species was decreased, whereas the relative concentration of oligomeric FexOy clusters and Fe2O3 particles was increased in the aged catalysts. A considerable decrease in the Brønsted acidity of catalysts was observed for the aged Fe-ZSM-5 catalysts.

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Preparation of Nanoporous Carbon Using an Aluminophosphate Framework Template ZHANG Min, ZHU Wan-Chun, LIU Gang, ZHANG Xiu-Yan, ZU Yan-Hong, ZHANG Wen-Xiang, YAN Wen-Fu, JIA Ming-Jun 2012, 33 (3):  465-472.  DOI: 10.1016/S1872-2067(11)60346-X Abstract ( 2415 )   [Full Text(HTML)] () PDF (613KB) ( 689 )   Different organic compounds, o-dihydroxybenzene, m-dihydroxybenzene, p-dihydroxybenzene, glycol, and cyclohexylamine, were used as the extra carbon source for a series of nanoporous carbon (NC) materials prepared by directly carbonizing composites containing citric acid and aluminum phosphate. The effect of the extra carbon source was studied. The structure and surface functional groups on the NC material were different with different extra carbon sources. The NC materials prepared using m-dihydroxybenzene, p-dihydroxybenzene or cyclohexylamine have excellent catalytic activity for the aerobic oxidation of benzyl alcohol to benzaldehyde.

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A Poly(hydroxyethyl methacrylate)-Immobilized Chiral Manganese(III)salen Catalyst for Asymmetric Epoxidation of α-Methylstyrene XU Guo-Jin, WEI Sai-Li, FAN Ying-Guo, ZHU Li-Bo, TANG Yu-Hai, ZHENG Yuan-Suo 2012, 33 (3):  473-477.  DOI: 10.1016/S1872-2067(11)60345-8 Abstract ( 2785 )   [Full Text(HTML)] () PDF (439KB) ( 919 )   Phenylalaninol was introduced in the C5 and C5′ position of a chiral Mn(III)salenCl compound, and the catalyst was then immobilized on poly(hydroxyethyl methacrylate) (pHEMA) by axial coordination. The catalytic system, with (R,R)(R,R)pHEMA-immobilized Mn(III)salenCl as catalyst and [bmim]PF6 as reaction medium, gave excellent catalytic activity and enantioselectivity with 80%–91% ee values and 84%–92% yields for the asymmetric epoxidation of α-methylstyrene. The catalyst can be reused several times without significant loss of catalytic activity. This was due to a chiral synergy between the chiral carbons of the amino alcohol and the chiral carbons of (R,R)-diaminocyclohexane.

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Catalytic Performance of Al-MCM-48 Molecular Sieves for Isopropylation of Phenol with Isopropyl Acetate Kandan VENKATACHALAM, Pitchai VISUVAMITHIRAN, Balachandran SUNDARAVEL, Muthiapillai PALANICHAMY, Velayutham MURUGESAN 2012, 33 (3):  478-486.  DOI: 10.1016/S1872-2067(11)60339-2 Abstract ( 2351 )   [Full Text(HTML)] () PDF (1081KB) ( 869 )   Al-MCM-48 molecular sieves (Si/Al molar ratios = 25, 50, 75, and 100) were synthesized hydrothermally using cetyltrimethylammonium bromide as the structure directing template. The orderly arrangement of mesopores was evident from the low angle X-ray diffraction patterns and transmission electron microscopy images. The catalytic performance of the materials was evaluated in the vapor phase isopropylation of phenol with isopropyl acetate. Phenol conversion decreased with the increase in the Si/Al ratio of the catalysts. The major reaction product was 4-isopropyl phenol with 78% selectivity. The delocalization of phenolic oxygen electron pair over the aromatic ring promoted para-selective alkylation. Such delocalization could be aided by the hydrophilic surface of the molecular sieves. Although an ester was used as the alkylating agent, phenyl isopropyl ether was not formed in the reaction.

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New Modified-Multiwall Carbon Nanotubes Paste Electrode for Electrocatalytic Oxidation and Determination of Hydrazine Using Square Wave Voltammetry Ali A. ENSAFI, Mahsa LOTFI, Hassan KARIMI-MALEH 2012, 33 (3):  487-493.  DOI: 10.1016/S1872-2067(11)60349-5 Abstract ( 2430 )   [Full Text(HTML)] () PDF (474KB) ( 1476 )   The application of p-aminophenol as a suitable mediator, as a sensitive and selective voltammetric sensor for the determination of hydrazine using square wave voltammetric method were described. The modified multiwall carbon nanotubes paste electrode exhibited a good electrocatalytic activity for the oxidation of hydrazine at pH = 7.0. The catalytic oxidation peak currents showed a linear dependence of the peaks current to the hydrazine concentrations in the range of 0.5–175 μmol/L with a correlation coefficient of 0.9975. The detection limit (S/N = 3) was estimated to be 0.3 μmol/L of hydrazine. The relative standard deviations for 0.7 and 5.0 µmol/L hydrazine were 1.7 and 1.1%, respectively. The modified electrode showed good sensitivity and selectivity. The diffusion coefficient (D = 9.5 × 10–4 cm2/s) and the kinetic parameters such as the electron transfer coefficient (α = 0.7) of hydrazine at the surface of the modified electrode were determined using electrochemical approaches. The electrode was successfully applied for the determination of hydrazine in real samples with satisfactory results.

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Alkylation of Benzene with 1-Decene Using Silica Supported Preyssler Heteropoly Acid: Statistical Design with Response Surface Methodology A. HAFIZI, A. AHMADPOUR, M. M. HERAVI, F. F. BAMOHARRAM, M. KHOSROSHAHI 2012, 33 (3):  494-501.  DOI: 10.1016/S1872-2067(11)60357-4 Abstract ( 2553 )   [Full Text(HTML)] () PDF (688KB) ( 848 )   The response surface method (RSM) was applied to study the liquid phase alkylation of benzene with 1-decene catalyzed by means of silica supported preyssler heteropoly acid. A three step experimental design was developed based on the central composite design (CCD). Catalyst loading, catalyst percent, and benzene to 1-decene molar ratio were used to optimize 1-decene conversion and linear alkylbanzene (LAB) yield. The results indicated that the quadratic model was significant for these two responses. The experimental results revealed that all variables had positive effect on 1-decene conversion. While increasing the catalyst loading tends to decrease LAB yield. Benzene to 1-decene molar ratio was found to be the most important factor that influenced LAB yield with a positive effect. Design expert software suggested several optimized solutions, among them the best choice was to use 31% catalyst loading, benzene to 1-decene molar ratio of 13, and catalyst percent of 3.6wt% for obtaining 100% conversion and 88% LAB production yield.

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Imidazol(in)ium-2-carboxylates as Latent, Thermally Activated Organocatalysts for Transesterification Reactions WANG Yan-Qin, LI Zhen-Jiang 2012, 33 (3):  502-507.  DOI: 10.1016/S1872-2067(11)60353-7 Abstract ( 3070 )   [Full Text(HTML)] () PDF (426KB) ( 613 )   1,3-Disubstituted imidazol(in)ium-2-carboxylates (ImCO2) were used as precatalysts for transesterification reactions of unactivated ethyl benzoate with monohydric alcohols, dihydric alcohols, and amino alcohols. Highly active N-heterocyclic carbenes (NHCs) are usually not used directly as catalysts because of their air and moisture sensitivity. Here they were liberated in situ by thermal decarboxylation of ImCO2 at designated temperatures. The results showed that the yield of the reactions reached up to 95% within 3 h using only 0.5 mol% catalyst. No active enol esters, molecular sieves, or a 20-fold excess of alcohol were used to drive the reaction to completion. It was proved that unsaturated imidazolium-2-carboxylates have a better activity than saturated species in this type of reaction. Different types of substituting groups of ImCO2 exhibited varied transesterification activity.

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Preparation of Nickel Phosphide/Mesoporous-TiO2 Catalyst and Its Hydrodesulfurization Performance YANG Zhu-Hong, LI Li-Cheng, WANG Yan-Fang, LIU Jin-Long, FENG Xin, LU Xiao-Hua 2012, 33 (3):  508-517.  DOI: 10.1016/S1872-2067(11)60358-6 Abstract ( 3040 )   [Full Text(HTML)] () PDF (726KB) ( 1205 )   Using mesoporous TiO2 (m-TiO2) as the support, novel nickel phosphide/m-TiO2 catalysts (Ni2P/m-TiO2) were prepared by a temperature-programmed reduction method. The influence of the Ni/P molar ratio and the amount of active component on the catalyst structure and the hydrodesulfurization (HDS) performance was investigated. The results indicated that the reduction of precursor with Ni/P = 1.25 yielded mainly Ni2P, and the optimum loading of Ni was 10%. The influence of m-TiO2 on the preparation and HDS performance of nickel phosphide catalysts was also evaluated by X-ray diffraction, N2 physisorption, field-emission scanning electron microscopy, and temperature-programmed reduction. The results showed that m-TiO2 with high crystallinity could dramatically decrease the reduction temperatures of Ni and P species. When the reduction temperatures were between 450 and 600 °C, the textures of the Ni2P/m-TiO2 catalysts were very similar and the specific surface areas were about 90 m2/g. The effects of the support on the dibenzothiophene HDS performance of the nickel phosphide catalysts were also investigated. The results showed that the order of dibenzothiophene conversion was Ni2P/m-TiO2 > Ni2P/SiO2 > Ni2P/P25.

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Liquid Phase Oxidation of Acetophenone over Rice Husk Silica Vanadium Catalyst Farook ADAM, Thiam-Seng CHEW, Jeyashelly ANDAS 2012, 33 (3):  518-522.  DOI: 10.1016/S1872-2067(11)60361-6 Abstract ( 2800 )   [Full Text(HTML)] () PDF (529KB) ( 1309 )   Rice husk silica catalyst loaded with 10 wt% vanadium was synthesized from agricultural biomass via a sol-gel synthetic route at pH = 9. The catalyst was characterized by different physico-chemical methods. The FTIR spectra showed the formation of Si–O–V and V=O stretching bands. The presence of vanadium was confirmed by EDX elemental analysis. RH-10V possessed a high specific surface area of 276 m2/g and pore volume of 0.83 ml/g. The prepared catalyst possessed a narrow pore size distribution centered around 7.9 nm. The catalytic performance of RH-10V was tested in the oxidation of acetophenone at 70 °C. RH-10V was found to be an active catalyst in the oxidation of acetophenone, producing 36.28% conversion efficiency. The products identified were benzoic acid, 2-hydroxyacetophenone, phenol, acetic acid, and 3-hydroxyacetophenone.

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Palladium-Catalyzed Three-Component Coupling Reaction of Benzyl Chlorides, Allyltributylstannane, and Carbon Monoxide: Efficient Synthesis of α,β-Unsaturated Ketones ZHANG Xin, FENG Xiu-Juan, LIU He-Song, QIN Yu-Hu, DAI Yao 2012, 33 (3):  523-529.  DOI: 10.3724/SP.J.1088.2011.10930 Abstract ( 2708 )   [Full Text(HTML)] () PDF (473KB) ( 960 )   Palladium-catalyzed three-component coupling reactions of benzyl chlorides, allyltributylstannane, and carbon monoxide were investigated. These three-component coupling reactions proceeded smoothly in the presence of Pd(PPh3)4 to give benzyl allyl ketone products, which could transform to α,β-unsaturated ketone compounds 6a–6n after purification via basic alumina column chromatography. α,β-Unsaturated ketone compounds 6b, 6d–h, 6j, 5l, and 6l–6n are unknown compounds, and their structure was characterized by infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, 13C nuclear magnetic resonance spectroscopy, and high-resolution mass spectroscopy.

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Oxidative Decarboxylation of L-Malate by Using a Synthetic Bioredox System JI De-Bin, WANG Lei, ZHOU Yong-Jin, YANG Wei, WANG Qian, ZHAO Zong-Bao 2012, 33 (3):  530-535.  DOI: 10.3724/SP.J.1088.2012.10938 Abstract ( 3003 )   [Full Text(HTML)] () PDF (682KB) ( 847 )   A synthetic bioredox system for the oxidative decarboxylation of L-malate to pyruvate was presented, with which the enzyme purification steps can be omitted. The bioredox system consisted of ME-t (mutant malic enzyme ME L310R/Q401C) and non-natural coenzyme nicotinamide flucytosine dinucleotide (NFCD+) catalyzes the oxidation of L-malate to pyruvate and concurrently generates the reduced coenzyme, NFCDH. Escherichia coli BL21(DE3) pET24b-ME-t cell lysates catalyze the oxidation of L-malate and produce pyruvate only, indicating that the cell lysates have the same substrate selectivity as the purified enzyme. NADH oxidase (NOX) from Enterococcus faecalis can oxidize NFCDH to regenerate NFCD+. Compared with the reaction system containing NAD+, ME lysates, and NOX lysates, the system containing NFCD+, ME-t lysates, and NOX lysates converts L-malate to pyruvate in 9% higher yield and with significantly less lactate formation. These results suggest that the synthetic bioredox system composed of ME-t and NFCD+ is easy to use and has higher product selectivity than the corresponding natural system dependent on NAD+. The synthetic bioredox system has the potential to substitute the purified enzyme. The results provide new opportunities for design and application of redox biocatalysts.

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Effects of Pr Doping on Structure and Catalytic Performance of Ru/CeO2 Catalyst for Ammonia Synthesis LIN Jian-Xin, ZHANG Liu-Ming, WANG Zi-Qing, WANG Rong, WEI Ke-Mei 2012, 33 (3):  536-542.  DOI: 10.3724/SP.J.1088.2012.10949 Abstract ( 3031 )   [Full Text(HTML)] () PDF (931KB) ( 968 )   The Pr-doped ceria supported ruthenium catalyst Ru/CeO2-PrO2 for ammonia synthesis was prepared by a redox co-precipitation method. The obtained catalyst samples were characterized by N2 physisorption, X-ray diffraction, H2 temperature-programmed reduction, CO chemisorption, temperature-programmed desorption of nitrogen, field-emission scanning electron microscopy, high resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The effects of Pr doping amount on the microstructure and catalytic properties of Ru/CeO2-PrO2 were investigated. The results showed that the composite oxide created form Pr-doped ceria has some influence on the Ru dispersion and surface texture. The activity test showed that the ammonia synthesis transformation frequency over the Ru/CeO2-PrO2 catalyst with 4% Pr was 12.13 × 10–2 s–1 at 10 MPa, 10000 h–1, and 425 ºC, which was 58% higher than that of Ru/CeO2. The improvement of electrical conductivity performance is the key factor for the higher catalytic activity.

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Effect of Mo on Performance of Ni-B/Boehmite Amorphous Alloy Catalyst for Thiophene Hydrodesulfurization QI Xue, SHI Qiu-Jie, CHEN Wei-Qing, ZHANG Rong-Bin 2012, 33 (3):  543-549.  DOI: 10.3724/SP.J.1088.2012.10750 Abstract ( 2730 )   [Full Text(HTML)] () PDF (750KB) ( 909 )   A series of Ni-Mo-B/boehmite amorphous alloy catalyst samples with different Mo contents were prepared by the impregnation-chemical reduction method. Thiophene hydrodesulfurization (HDS) was chosen as a probe reaction to investigate the influence of Mo contents on HDS activity of the Ni-Mo-B/boehmite catalyst. The catalyst samples were characterized by X-ray diffraction, differential scanning calorimetry, inductive coupled plasma, temperature-programmed reduction, temperature-programmed desorption, X-ray photoelectron spectroscopy, and transmission electron microscopy. The addition of Mo increased the dispersion of Ni active species, improved the thermal stability of Ni-B/boehmite, decreased the reduction temperature, weakened the strength of Ni_H bonds, increased adsorption centers and acidity, and therefore promoted catalyst activity dramatically. At low temperature of 220 oC, when the Mo/Ni mass ratio is 12%, the conversion of thiophene is the highest, up to 73.9%.

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Preparation of Pt-Doped TiO2 by Hydrothermal Method and Its Photocatalytic Performance under Visible Light Irradiation JING Ming-Jun, WANG Yan, QIAN Jun-Jie, ZHANG Min, YANG Jian-Jun 2012, 33 (3):  550-556.  DOI: 10.3724/SP.J.1088.2012.11011 Abstract ( 3120 )   [Full Text(HTML)] () PDF (806KB) ( 1900 )   Pt-doped TiO2 was prepared by a hydrothermal method using nanotubular titanic acid (NTA) as the precursor. The pH values before and after the hydrothermal reaction were compared. It was found that the hydroxyl group on the surface of NTA could neutralize the chloroplatinic acid during the hydrothermal reaction, which resulted in a pH value increase. The nanotubular structure of NTA was destroyed to form nanoparticles at 130 °C accompanied by the crystal transformation from an orthorhombic system to anatase TiO2. The X-ray photoelectroy spectroscopy results showed that platinum was present mainly in the form of Pt2+. The photocatalytic activity was evaluated by monitoring the oxidation of propylene under visible light irradiation. The results indicated that Pt-TiO2 prepared at 160 oC showed the highest photocatalytic activity at visible light (λ ≥ 420 nm). The mechanism of Pt-doping into TiO2 and the visible light sensitization of Pt-doped TiO2 were discussed.

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Catalytic Combustion of Vinyl Chloride Emission over CeO2-MnOx Catalyst WAN Yi-Ling, ZHANG Chuan-Hui, GUO Yang-Long, GUO Yun, LU Guan-Zhong 2012, 33 (3):  557-562.  DOI: 10.3724/SP.J.1088.2012.11003 Abstract ( 2386 )   [Full Text(HTML)] () PDF (535KB) ( 1254 )   CeO2-MnOx catalyst samples with different Mn/(Ce+Mn) molar ratios (0, 1/4, 1/2, 3/4, and 1) prepared by the citric acid (CA) sol-gel method were studied for catalytic combustion of vinyl chloride (VC) emission. The effects of preparation conditions and operation parameters on the catalytic performance of CeO2-MnOx were investigated. The catalyst samples were characterized by N2 adsorption, X-ray diffraction (XRD), and H2 temperature-programmed reduction (H2-TPR). In the catalytic combustion of VC over CeO2-MnOx, the products containing HCl, CO2, and H2O were produced and there were no byproducts such as chlorohydrocarbons and chlorine. The CeO2-MnOx catalyst with the molar ratio of CA:Mn:Ce = 0.30:0.50:0.50 showed the best catalytic performance and had better operating flexibility over the ranges of gas hourly space velocity (GHSV) of 10000–30000 h-1 and VC concentration of 0.05%–0.15%. The temperatures at 50% conversion (110 oC) and at 99% conversion (220 oC) were achieved at VC concentration of 0.1% and GHSV of 15000 h-1. XRD characterization indicated that only the characteristic diffraction peaks of CeO2 with the cubic fluorite structure appeared and no characteristic diffraction peaks of MnOx species appeared over CeO2-MnOx catalyst. XRD and H2-TPR results indicated that Mn ions were incorporated into the CeO2 lattice to form Ce-Mn-O solid solution, which was favorable for improving the reactivity of active oxygen species on the catalyst surface and thereby enhanced the catalyst activity.

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Preparation and Characterization of BaTiO3-BaAl2O4-Al2O3 Composite Support and Catalytic Performance of Its Nickel-Based Catalyst for CO2 Reforming of Methane HU Quan-Hong, LI Xian-Cai, YANG Ai-Jun, YANG Chun-Yan 2012, 33 (3):  563-569.  DOI: 10.3724/SP.J.1088.2012.10505 Abstract ( 2767 )   [Full Text(HTML)] () PDF (886KB) ( 905 )   Nickel-based catalyst supported on BaTiO3 possesses higher initial activity for carbon dioxide reforming of methane. However, the specific surface area of the BaTiO3 support is too small, and this restricts its application as a catalyst support. A BaTiO3-BaAl2O4-Al2O3 composite support was prepared by the sol-gel method using hexadecyltrimethylammonium bromide as the structure template. The BaTiO3-BaAl2O4-Al2O3 composite was characterized by X-ray diffraction, infrared spectroscopy, N2 adsorption-desorption, transmission electron microscopy, and H2 temperature-programmed reduction. The catalytic performance of the Ni/BaTiO3-BaAl2O4-Al2O3 catalyst was investigated by CO2 reforming of CH4. The results showed that the BaTiO3-BaAl2O4-Al2O3 composite support owns a porous texture and high specific surface area, the BaTiO3 and BaAl2O4 phases, whose crystalline size is in the range of 20–50 nm, exist on the inside and outside surface of the composite support in the form of crystalline particles. The size of micropores of the composite support is 10–20 nm, The presence of both BaTiO3 and BaAl2O4 phases on the surface of the composite support weakens the strong interaction between the nickel species and γ-Al2O3 of the Ni/BaTiO3-BaAl2O4-Al2O3 catalyst, and the possibility of the formation of NiAl2O4 spinel is decreased. The Ni/BaTiO3-BaAl2O4-Al2O3 catalyst with 17.33% Ba content shows the highest activity and excellent stability for CH4 reforming with CO2 to synthesis gas.

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Catalytic Performance of Bi-functional WC/HZSM-5 Catalysts for n-Hexane Aromatization SHI Mei-Qin, CHEN Ning-Ning, MA Chun-An, LI Ying, WEI Ai-Ping 2012, 33 (3):  570-575.  DOI: 10.3724/SP.J.1088.2012.10965 Abstract ( 2907 )   [Full Text(HTML)] () PDF (582KB) ( 797 )   Bi-functional tungsten carbide (WC) supported on HZSM-5 (WC/HZSM-5) catalyst samples were prepared and studied in n-hexane aromatization. Two series of catalyst samples with varying WC loadings were synthesized by in-situ reduction-carbonization (WC/HZSM-5(RC)) and impregnation methods (WC/HZSM-5(IP)). The catalyst samples were characterized by NH3 temperature-programmed desorption, X-ray diffraction, and scanning electron microscopy combined with energy dispersive spectroscopy. The results showed that WC/HZSM-5(RC) has much higher catalytic activity than WC/HZSM-5(IP). The aromatic selectivity on 5%WC/HZSM-5(RC) was 10.28%, which was much higher than that of HZSM-5 (2.56%). The aromatics (benzene, toluene, and xylene) content in liquid products was 85.07%, much higher than that of HZSM-5 (67.71%). These results are interpreted by the bi-functional mechanism due to the synergistic action between the HZSM-5 and WC.

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Influence of Iron Precursors on NH3-SCR Behavior of Fe/β Catalyst ZHANG Ze-Kai, YU He, LIAO Bing-Bing, HUANG Hai-Feng, CHEN Yin-Fei 2012, 33 (3):  576-580.  DOI: 10.3724/SP.J.1088.2012.11012 Abstract ( 2323 )   [Full Text(HTML)] () PDF (887KB) ( 1110 )   The precursor effects of Fe precursors on the selective catalytic reduction of NOx by NH3 (NH3-SCR) over Fe/β catalyst were evaluated. Three different precursors, ferrocene, ferric nitrate, and ferric chloride, were chosen to prepare Fe/β catalyst by liquid impregnation method. The catalyst samples were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The results showed that the activity of Fe/β from ferrocene was superior to the others. Under the reaction condition of GHSV 60000 h–1, 50% conversion of NOx was reached at 150 oC and full conversion was obtained at 260 oC. Characterization indicated that ferrocene is profitable to improve the particle size, particle distribution, and redox properties of FeOx species, leading to the NH3-SCR activity promotion.