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Chinese Journal of Catalysis
2011, Vol. 32, No. 2
Online: 26 January 2011


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Prof. Menéndez and coworkers in their article on pages 207–216 reviewed the recent development of carbon catalysts for decomposition and CO₂ reforming of methane. The dry reforming reaction over carbonaceous catalysts can be considered a combination of CH₄ decomposition and CO₂ gasification of carbon deposits. The decomposition of CH₄ gives rise to hydrogen and carbonaceous deposits, which block the active centers on the carbon catalyst. Then, the deposits, at least those which are highly reactive, are gasified by the CO₂, leading to an in situ and continuous regeneration of the active centers on the carbon catalyst.

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Table of Contents for Vol.32 No. 2 2011, 32 (2):  0-0.  Abstract ( 1340 )   PDF (1910KB) ( 1042 )

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Carbon Materials as Catalysts for Decomposition and CO2 Reforming of Methane: A Review Beatriz FIDALGO, J. Angel MENENDEZ* 2011, 32 (2):  207-216.  DOI: 10.1016/S1872-2067(10)60166-0 Abstract ( 2755 )   [Full Text(HTML)] () PDF (832KB) ( 2180 )   The decomposition and CO2 reforming of methane, respectively, are promising alternatives to industrial steam methane reforming. In recent years, research has been focused on the development of catalysts that can operate without getting deactivated by carbon deposition, where, in particular, carbon catalysts have shown positive results. In this work, the role of carbon materials in heterogeneous catalysis is assessed and publications on methane decomposition and CO2 reforming of methane over carbon materials are reviewed. The influence of textural properties (BET surface area and micropore volume, etc.) and oxygen surface groups on the catalytic activity of carbon materials are discussed. In addition, this review examines how activated carbon and carbon black catalysts, which are the most commonly used carbon catalysts, are deactivated. Characteristics of the carbon deposits from methane are discussed and the influence of the reactivity to CO2 of fresh carbon and carbonaceous deposits for high and steady conversion during CO2 reforming of CH4 are also considered.

Research Briefing

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Dynamic Hydrothermal Synthesis of a b-Oriented MFI Zeolite Film LI Xianming1, WANG Zhengbao1,*, ZHENG Jie1, SHAO Shiqun1, WANG Yinchao1, YAN Yushan1,2 2011, 32 (2):  217-223.  DOI: 10.1016/S1872-2067(10)60167-2 Abstract ( 2813 )   [Full Text(HTML)] () PDF (643KB) ( 1350 )   Continuous b-oriented MFI zeolite films were prepared on stainless steel substrates by dynamic hydrothermal synthesis using a rotating convection oven. The influences of rotation speed, crystallization temperature and crystallization time were studied. X-ray diffraction was used to identify the orientation of the zeolite films. Compared with the static method, a shorter synthesis time, a more uniform particle size distribution and better film orientation were observed for the dynamic method, and this is attributed to the low concentration and thermal gradients that exist in the bulk solution and to the washing action of the bulk solution toward the substrate surface.

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Monolayer Dispersed Ru-Zn Catalyst and Its Performance in the Selective Hydrogenation of Benzene to Cyclohexene SUN Haijie, ZHOU Xiaoli, CHEN Zhihao, GUO Wei, LIU Zhongyi*, LIU Shouchang 2011, 32 (2):  224-230.  DOI: 10.1016/S1872-2067(10)60158-4 Abstract ( 2933 )   [Full Text(HTML)] () PDF (903KB) ( 1125 )   A series of Ru-Zn catalysts with different Zn loadings were prepared by co-precipitation. X-ray diffraction and X-ray photoelectron spectroscopy results showed that a large part of the Zn in the Ru-Zn catalysts were present in the form of ZnO and the ZnO on the catalyst surface could react with ZnSO4 in the slurry to form a basic zinc sulfate salt during hydrogenation. The content of the basic salt increased with an increase in the Zn loading of the catalysts. This resulted in a decrease in catalyst activity and an increase in selectivity for cyclohexene. When the Zn loading was 8.6%, the basic salt dispersion was close to monolayer dispersion on the catalyst surface. When the catalysts were pretreated in the presence of 0.6 mol/L ZnSO4 solution at 140 °C and at 5 MPa H2, a cyclohexene selectivity of 69.8% and a benzene conversion of 84.4% was achieved after 20 min.

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Enantioselective Cycloetherification in a Micellar Catalysis System Bhupesh S. SAMANT1,*, Sunil S. BHAGWAT2 2011, 32 (2):  231-234.  DOI: 10.1016/S1872-2067(10)60169-6 Abstract ( 2588 )   [Full Text(HTML)] () PDF (278KB) ( 1027 )   The enantioselective cycloetherification of substituted keto phenols into their corresponding dihydrobenzofuran derivatives was carried out using hydrogen peroxide and chiral quaternary ammonium iodide in micellar media. This approach increased the conversion rate of cycloetherification and also widened the scope of this particular reaction for various substituted keto phenols with electron withdrawing as well as electron donating functionalities. The use of a surfactant in the cycloetherification reaction increased the yield of the corresponding enantioselective dihydrobenzofuran four times. The conversion rate of keto phenols into their corresponding dihydrobenzofuran derivatives was proportional to the concentration of the surfactant used in the reaction.

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Ultra-deep Oxidative Desulfurization of Fuel Oil Catalyzed by Dawson-Type Polyoxotungstate Emulsion Catalysts ZHANG Yongna1,2, WANG Lu1,2, ZHANG Yuliang1,2, JIANG Zongxuan1,#, LI Can1,* 2011, 32 (2):  235-239.  DOI: 10.1016/S1872-2067(10)60170-2 Abstract ( 2631 )   [Full Text(HTML)] () PDF (509KB) ( 1069 )   The Dawson-type polyoxotungstate emulsion catalysts Q18P2W18, Q18P2W17, and Q18P2W12 were successfully synthesized and characterized by IR and 31P MAS NMR. They were used for the oxidation of sulfur-containing compounds such as 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzothiophene (DBT), benzothiophene (BT), and 2,5-dimethythiophene (2,5-DMT) with H2O2 as an oxidant under mild conditions. The activity of the catalysts decreased in the order: Q18P2W12 > Q18P2W17 > Q18P2W18. The oxidative reactivity of the sulfur-containing compounds decreased according to DBT > 4,6-DMDBT > BT > 2,5-DMT. BT was completely oxidized into the corresponding sulfone upon catalysis by Q18P2W12 at 60 °C for 30 min.

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Effect of Alumina Supports on the Formation of Active Phase of Selective Hydrodesulfurization Catalysts Co-Mo/Al2O3 Qiherima1,3, LI Huifeng2, YUAN Hui2, ZHANG Yunhong1, XU Guangtong2,* 2011, 32 (2):  240-249.  DOI: 10.1016/S1872-2067(10)60171-4 Abstract ( 2793 )   [Full Text(HTML)] () PDF (542KB) ( 1142 )   Two different commercial alumina supports were used for the preparation of selective hydrodesulfurization (HDS) catalysts Co-Mo/Al2O3. The effect of support properties on the HDS activity and selectivity of the corresponding Co-Mo catalysts were studied by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning transmission electron microscopy- energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The HDS activity and selectivity were measured using a continuous flow fixed-bed microreactor. The Al2O3 support with higher crystallinity and fewer hydroxyl groups had a moderate metal-support interaction, which resulted in an increase of the average slab length and stacking number of MoS2. This gave more formation of the active CoMoS phase and an increase in HDS activity and selectivity.

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Preparation of Highly Loaded LaMnOx/SBA-15 Catalyst and Its Toluene Combustion Performance ZHANG Zekai, LIANG Yiwei, REN Qianru, LIU Huayan, CHEN Yinfei* 2011, 32 (2):  250-257.  DOI: 10.1016/S1872-2067(10)60172-6 Abstract ( 2822 )   [Full Text(HTML)] () PDF (560KB) ( 1149 )   A highly loaded LaMnOx/SBA-15 catalyst (60%) was prepared by step coating NH3/water vapor-induced internal hydrolysis (VIH) and characterized by X-ray diffraction, N2 adsorption-desorption, and temperature-programmed reduction (H2-TPR). Its catalytic performance for toluene combustion was also evaluated. The results showed that the VIH process clearly improved the activity of the LaMnOx/SBA-15 catalyst. Using a toluene concentration of 0.86% and a GHSV of 5000 h–1, a 50% toluene conversion was obtained at 205 °C for the LaMnOx/SBA-15 sample prepared by the VIH process. This temperature was 105 °C lower than that for the sample prepared by conventional impregnation. N2 adsorption-desorption and H2-TPR revealed that the VIH process improved the distribution of the LaMnOx active phase in the pores of SBA-15 and improved its reduction properties. The optimal VIH conditions were a temperature of 60 °C and a reaction time of 40 min.

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Direct Hydroxylation of Benzene to Phenol over Fe3O4 Supported on Nanoporous Carbon Pezhman ARAB1, Alireza BADIEI1,*, Amir KOOLIVAND1, Ghodsi MOHAMMADI ZIARANI2 2011, 32 (2):  258-263.  DOI: 10.1016/S1872-2067(10)60173-8 Abstract ( 2385 )   [Full Text(HTML)] () PDF (675KB) ( 1661 )   Fe3O4/CMK-3 was prepared by impregnation and used as a catalyst for the direct hydroxylation of benzene to phenol with hydrogen peroxide. The iron species in the prepared catalyst was Fe3O4 because of the partial reduction of iron(III) to iron(II) on the surface of CMK-3. The high catalytic activity of the catalyst arises from the formation of Fe3O4 on the surface of CMK-3 and the high selectivity for phenol is attributed to the consumption of excess hydroxyl radicals by CMK-3. The effect of temperature, reaction time, volume of H2O2, and amount of catalyst on the catalytic performance of the prepared catalyst were investigated. Under optimized conditions, the catalyst showed excellent catalytic performance for the hydroxylation of benzene to phenol and 18% benzene conversion was achieved with 92% selectivity for phenol and with a TOF value of 8.7 h-1. The stability of catalyst was investigated by determining its activity after the fourth run and it was found to have decreased to 80% of the fresh catalyst’s activity.

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Nitrous Oxide Decomposition over Alkali-Promoted Magnesium Cobaltite Catalysts Bahaa M. ABU-ZIED* 2011, 32 (2):  264-272.  DOI: 10.1016/S1872-2067(10)60174-X Abstract ( 3036 )   [Full Text(HTML)] () PDF (516KB) ( 1480 )   The direct decomposition of N2O was investigated over a series of magnesium cobaltite catalysts, MgxCo1-xCo2O4 (0.0 ≤ x ≤ 1.0), which were prepared by the thermal decomposition of stoichiometric amounts of magnesium hydroxide and cobalt acetate. The thermal genesis of the different catalysts from their precursors was explored using thermogravimetric analysis, differential thermal analysis, and X-ray diffraction. Texture analysis was carried out using N2 adsorption at –196 °C. We found that all the catalysts that were calcined at 500 °C have a spinel structure. N2O decomposition activity was found to increase with an increase in the spinel structure’s magnesium content. The influence of alkali cation promoters (Li, Na, K, and Cs) on the activity of the most active catalyst in the MgxCo1-xCo2O4 series, i.e. MgCo2O4, was also investigated. The sequence of the promotional effect was found to be: un-promoted < Li < Na < Cs < K-promoted catalyst. The reason for the increase in activity for the added alkali cations was electronic in nature. Additionally, the dependence of the activity on the K/Co ratio was also determined. The highest activity was obtained for the catalyst with a K/Co ratio of 0.05. A continuous decrease in activity was obtained for higher K/Co ratios. This decrease in activity was attributed to the elimination of mesoporosity in the catalysts with K/Co ratios > 0.05, based on N2 adsorption and scanning electron microscopy results.

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Deactivation and Regeneration of Nickel-Based Catalysts for Steam-Methane Reforming Seyed Meysam HASHEMNEJAD, Matin PARVARI* 2011, 32 (2):  273-279.  DOI: 10.1016/S1872-2067(10)60175-1 Abstract ( 3189 )   [Full Text(HTML)] () PDF (1303KB) ( 4483 )   The deactivation of nickel catalysts used in Arak and Razi petrochemical complexes followed by catalyst regeneration was evaluated. The characterization of the different structures was made by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and carbon & sulfur analyzer. The Ni particle size was estimated from XRD patterns and TEM graphs. The agglomeration of nickel particle and the poison by sulfur components were recognized as the main reasons in deactivation of Arak and Razi catalysts, respectively. The activity of the used catalysts before and after regeneration was measured on methane steam reforming at a CH­4:H2O ratio of 1:3 at 850 oC. The regeneration processes for Arak and Razi samples were performed with CO2 as an oxidative atmosphere and steam as a regenerating agent, respectively. The results show that, (1) no residual sulfur components were on the regenerated Razi catalyst surface without changing the structure of the catalyst and the regenerated catalyst has gained 80% of its catalytic activity, and that (2) the nickel particle size of regenerated Arak specimen decreased remarkably as measured by Debye-Scherrer equation from XRD patterns. TEM images were in agreement with the XRD results and indicated a decrease in nickel particle size of regenerated catalyst. Additionally, in both regenerated catalysts all the coke on the surface of the support was eliminated after regeneration.

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Hydrogenation of Olefins Catalyzed by Polymer-Supported Palladium-Imidazole Udayakumar VELU1, Alexander STANISLAUS1, Gayathri VIRUPAIAH1,*, Shivakumaraiah2, Viswanathan BALASUBRAMANIAN3 2011, 32 (2):  280-285.  DOI: 10.1016/S1872-2067(10)60176-3 Abstract ( 2437 )   [Full Text(HTML)] () PDF (312KB) ( 1155 )   A polymer-supported palladium-imidazole catalyst was used to catalyze the hydrogenation of various olefins under mild conditions. The rate of hydrogenation was studied. The effects of factors such as substrate concentration, catalyst concentration, partial pressure of hydrogen and temperature on initial rate of reaction of selected olefins were investigated. A mechanism for the reaction was proposed from the rate equation. The effects of the solvent and structure of the olefin on the rate of hydrogenation were investigated. The catalyst showed good reusability without any leaching of metal from the support. The homologous analog of the polymer-supported catalyst could not be used as catalyst for the hydrogenation of olefins in methanol because there was precipitation of the metal during reaction.

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Effect of Si Doping on the Microstructure and Photocatalytic Performance of TiO2 Hollow Microspheres LI Gang, LIU Fang, YANG Qihua, ZHANG Zhao* 2011, 32 (2):  286-292.  DOI: 10.3724/SP.J.1088.2010.00819 Abstract ( 3328 )   [Full Text(HTML)] () PDF (731KB) ( 1173 )   Solid precursory microspheres composed of Ti/Si species were in situ formed on the surface of a colloid carbon microsphere template derived from glucose polymerization and carbonization by a one-pot hydrothermal method using ammonium fluorotitanate, ammonium fluorosilicate, and glucose as source materials. Si-doped TiO2 hollow microspheres were then obtained after calcination and removal of the carbon microsphere template at high temperature. High-resolution transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and N2 adsorption-desorption were used to characterize the samples. The effect of Si doping on the microstructure and photocatalytic performance of the TiO2 hollow microspheres was investigated. The results confirmed that the Si element entered into the lattice of TiO2 and formed Si–O–Ti bond, which could not only effectively suppress the phase transformation from anatase to rutile, but also restrain the rapid growth of TiO2 nanocrystallites during the calcination process. The average grain size of the nanocrystallites constituting the shell of the microspheres decreased gradually and the specific surface area and pore volume of the hollow microspheres increased progressively with the increase in the amount of Si doping. The photocatalytic activity of the Si-doped TiO2 hollow microspheres was measured under ultraviolet light using methylene blue solution as a simulated degradation model. The results demonstrated that the degradation efficiency of TiO2 hollow microspheres enhanced gradually with increasing Si doping in its mol fraction range of 0–0.5. Especially, the degradation efficiency of TiO2 hollow microspheres is 1.25 times that of P25 when the Si mol fraction is 0.5.

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A Comparative Study of Methanol to Olefins over SSZ-13 and RUB-50 Zeolites LI Peng, ZHANG Weiping*, HAN Xiuwen, BAO Xinhe* 2011, 32 (2):  293-298.  DOI: 10.3724/SP.J.1088.2010.00902 Abstract ( 3480 )   [Full Text(HTML)] () PDF (614KB) ( 1191 )   The effect of cage size on the catalytic performance of SSZ-13 with CHA structure and RUB-50 with LEV structure has been comparatively investigated in the methanol-to-olefin (MTO) reaction. The zeolite structure and coke deposit were characterized by X-ray diffraction, N2 adsorption-desorption, solid-state NMR, thermogravimetry and UV-Vis spectroscopy. It is found that SSZ-13 zeolite with larger cage size has better stability and higher propylene selectivity in the MTO reaction, while RUB-50 zeolite with smaller cage size has higher ethylene selectivity. Most of nonframework Al can be extracted, and the acidity is altered to some extent after the zeolites were washed with dilute acid. However, this would not obviously change the ratio of propylene to ethylene in the products. In addition, the volume of carbonaceous species is dependent on the zeolite cage size. More ethylene would be produced in the zeolite with smaller cage size. Thus, the zeolite cage size is very important in altering the ethylene and propylene selectivity in the MTO reaction.

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Synthesis of a New Biphophorus Ligand and Its Application in Hydroformylation of 2-Butene ZHANG Lin, LI Chun, FU Haiyan, YUAN Maolin, LI Ruixiang, CHEN Hua* 2011, 32 (2):  299-302.  DOI: 10.3724/SP.J.1088.2010.00833 Abstract ( 3096 )   [Full Text(HTML)] () PDF (483KB) ( 845 )   A new biphosphorus ligand has been developed and applied in the rhodium-catalyzed regioselective hydroformylation of 2-butene. The effects of ligand/Rh ratio, reaction temperature, reaction pressure, and substrate/catalyst molar ratio were investigated. High activity and regioselectivity were achieved. The n-aldehyde/iso-aldehyde ratio of about 28.5 was obtained at 60 °C, and the TOF increased to 660 h-1 at the pressure of 2.0 MPa.

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Influence of Supported-Calcination Temperature on the Performance of Pd/Zr0.5Al0.5O1.75 Catalyst Used in Lean-Burn Natural Gas Vehicles WANG Yun, TANG Shiyun, LONG Enyan, LIN Zhien, GONG Maochu, CHEN Yaoqiang* 2011, 32 (2):  303-308.  DOI: 10.3724/SP.J.1088.2011.00910 Abstract ( 3360 )   [Full Text(HTML)] () PDF (544KB) ( 1092 )   The Zr0.5Al0.5O1.75 mixed oxide was prepared by coprecipitation method, and calcined at different temperatures and then used as a support to prepare a 1.5% Pd/Zr0.5Al0.5O1.75 catalyst. The catalyst activity and H2O resisting properties were evaluated in a mixed gas that simulated the exhaust of lean-burn natural gas fuelled vehicles (lean-burn NGVs). The catalyst was further characterized by N2 adsorption-desorption, X-ray diffraction, H2 temperature-programmed reduction, O2 temperature-programmed desorption and CO chemisorption. It was found that the catalyst activity was greatly influenced by the calcination temperature of the Zr0.5Al0.5O1.75 support. For the catalyst with the support calcined at 950 °C, the light-off temperature (T50) and complete conversion temperature (T90) of methane in the absence of H2O were 274 and 315 °C, respectively. In the presence of H2O, T50 and T90 were 325 and 356 °C, respectively. The results indicated that the catalyst had higher catalytic activity at low temperature and higher capability to resist H2O poisoning.

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Effect of La and Mn Promoters on Structure and Performance of CuZr Catalyst Prepared by Complete Liquid-Phase Technology GAO Zhihua, HUANG Wei*, YIN Lihua, XIE Kechang 2011, 32 (2):  309-314.  DOI: 10.3724/SP.J.1088.2011.00909 Abstract ( 2665 )   [Full Text(HTML)] () PDF (500KB) ( 751 )   A CuZr slurry catalyst promoted by La and Mn additives was prepared by complete liquid-phase technology. The performance of the catalyst for direct synthesis of dimethyl ether from syngas was evaluated in a slurry reactor. The catalyst was characterized by NH3 temperature-programmed desorption, powder X-ray diffraction, N2 adsorption-desorption, X-ray photoelectron spectroscopy, and H2 temperature-programmed reduction. The results indicated that the addition of La and Mn promoters to the CuZr slurry catalyst effectively improved the active metal dispersibility and increased the catalyst surface area. The presence of La and Mn also increased the surface vacancy of ZrO2, improved the number of highly dispersed CuO and reducible CuO, and thereby enhanced the interaction between Cu and Zr. Consequently, the catalyst activity was obviously increased.

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Effects of Citric Acid-modification on the Performance of Nano-Ba-MgO Sup-port and Its Ru-Based Catalysts for Ammonia Synthesis HUO Chao*, XIA Qinhua, PAN Meihua, YANG Xiazhen, LUO Yan, LIU Huazhang 2011, 32 (2):  315-320.  DOI: 10.3724/SP.J.1088.2011.00934 Abstract ( 2925 )   [Full Text(HTML)] () PDF (524KB) ( 984 )   A series of citric acid-modified Ba-MgO supports (Ba-MgO(CA)) were prepared by ultrasound electrostatic adsorption (UEA), and the corresponding Ru catalysts for ammonia synthesis were then prepared by the impregnation method. Their physical and chemical properties were characterized by scanning electronic microscopy, X-ray diffraction, nitrogen physical adsorption, inductively coupled plasma-atomic emission spectrometry, and infrared spectroscopy. The results showed that the introduction of citric acid during the preparation of the support changed not only the chemical and textural properties of the nano-Ba-MgO support but also the doping amount of Ba in the Ba-MgO(CA) support. When the concentration of citric acid was 2.0 mmol/L, the Ru/Ba-MgO(CA) catalyst exhibited the highest catalytic activity for ammonia synthesis with a reaction rate of 63.20 mmol/(g·h) at 400 oC, 10 MPa, and 10 000 h-1, which is 21% higher than that of unmodified Ru/Ba-MgO.

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Influence of Carbon Aerogel (CA) Pore Structure on Photodegradation of Methyl Orange over TiO2/CA CUI Huanan, ZHAO Zhenhua, LIANG Yeru, SHI Jianying*, WU Dingcai*, LIU Hong, FU Ruowen 2011, 32 (2):  321-324.  DOI: 10.3724/SP.J.1088.2011.00932 Abstract ( 4095 )   [Full Text(HTML)] () PDF (428KB) ( 1328 )   Two kinds of carbon aerogel (CA), CA125 and CA500, with pore diameters of ~18 nm and > 50 nm, respectively, were used as supports to prepare TiO2/CA photocatalysts with the CA content of 20%. X-ray diffraction, scanning electron microscopy and N2 adsorption-desorption were used to characterize the crystal structure, morphology, and pore structures of the TiO2/CA photocatalysts, respectively. The loaded TiO2 was mainly anatase with a little amount of rutile, which was homogeneously dispersed on the CA support. The activity of TiO2/CA125 was much higher than that of TiO2/CA500 in the photodegradation of methyl orange. The photodegradation rate over TiO2/CA is mainly influenced by the pore structure of the catalysts. The favorable adsorption and suitable confinement effect of mesopore structure are beneficial to the photodegradation of methyl orange. Therefore, TiO2/CA125 with the large amount of mesopores displays the higher photocatalytic activity than TiO2/CA500.

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Effects of Supports on Catalytic Properties of the Supported Ni-B Catalysts for Selective Hydrogenation of 2-Ethylanthraquinone to H2O2 CHEN Xueying*, QIAO Minghua, HE Heyong 2011, 32 (2):  325-332.  DOI: 10.3724/SP.J.1088.2011.00941 Abstract ( 3416 )   [Full Text(HTML)] () PDF (780KB) ( 961 )   Supported Ni-B amorphous alloy catalysts were prepared by a reductant-impregnation method using commercial SiO2, γ-Al2O3, and active carbon (AC) as supports. The effects of the supports on the texture, thermal stability, and catalytic properties of the supported Ni-B catalysts in selective hydrogenation of 2-ethylanthraquinone (eAQ) to H2O2 were studied. It was found that the crystallization temperature of the supported Ni-B catalysts is much higher than ultrafine Ni-B and the stability sequence is Ni-B/AC > Ni-B/SiO2 > Ni-B/γ-Al2O3. The catalytic activity of the supported Ni-B catalysts is in the order Ni-B/SiO2 > Ni-B/γ-Al2O3 > Ni-B/AC, and the C=O selectivity is Ni-B/AC > Ni-B/SiO2 > Ni-B/γ-Al2O3. The different activity of the supported Ni-B catalysts can be attributed to the deviation in the active surface area of the catalysts and the different pore structure of the supports. The different selectivity can be attributed to the different uniformity of the active sites on the catalysts and the different surface properties of the supports.

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Reaction Dynamics Behavior of Epoxidation of Allyl Chloride with Hydrogen Peroxide Catalyzed by Ti-MWW FANG Xiangqing,WANG Yuning, DENG Xiujuan, WU Haihong, WU Peng, LIU Yueming*, HE Mingyuan 2011, 32 (2):  333-339.  DOI: 10.3724/SP.J.1088.2011.00820 Abstract ( 3379 )   [Full Text(HTML)] () PDF (586KB) ( 860 )   The reaction mechanism for epoxidation of allyl chloride (ALC) with H2O2 catalyzed by Ti-MWW was studied in detail. The results showed that the epoxidation of ALC is first order reaction with respect to the catalyst amount and is the reactions between zero and first order with respect to the substrate concentration and the oxidant concentration. For H2O2, the epoxidation is first order reaction when its concentration is lower than 0.67 mol/L and zero order when its concentration is higher than 2 mol/L. For ALC, only when its concentration is very high, the obvious decrease of the reaction order from 1 to 0 was observed. And the epoxidation reaction rate is an S-type curve when the Ti content in Ti-MWW increases.

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Reduction Mechanism of Ni/Al2O3 Catalyst Reduced by Cold Plasma Jet for Carbon Dioxide Reforming of Methane HU Shijing, LONG Huali, XU Yan, SHANG Shuyong, YIN Yongxiang* 2011, 32 (2):  340-344.  DOI: 10.3724/SP.J.1088.2011.00818 Abstract ( 3528 )   [Full Text(HTML)] () PDF (549KB) ( 1257 )   The reduction mechanism of the Ni/Al2O3 catalyst reduced by atmospheric pressure cold plasma jet was analyzed by theoretical calculation and experiments. First, the dissociation degree of hydrogen and reduction time required were theoretically estimated according to the collision model based on the idea of catalyst reduction by hydrogen atoms. Second, X-ray diffraction and activity measurement were used to test the catalyst reduced by 90% Ar-10% H2 cold plasma jet, which clearly exhibited the practical reduction process and reduction time. The reduction time obtained by theoretical calculation was much consistent with the experiment result.

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Dehydration of Glycerol to Acetol over Copper-Based Catalysts NIU Shasha1,2, ZHU Yulei1,3,*, ZHENG Hongyan3, ZHANG Wei1,2, LI Yongwang1,3 2011, 32 (2):  345-351.  DOI: 10.3724/SP.J.1088.2011.00914 Abstract ( 3477 )   [Full Text(HTML)] () PDF (527KB) ( 1627 )   A series of Cu-based catalysts were prepared by the co-precipitation method, and their catalytic properties for the dehydration of glycerol to acetol were tested under N2 atmosphere in a stainless steel autoclave. The results showed that the Cu/SiO2 catalyst had higher catalytic activity than other catalysts. However, acetol can easily react with hydrogen that originated from the reaction process to 1,2-propanediol, leading to the low selectivity for acetol. Therefore, a fixed-bed reactor was selected to further investigate the effects of reaction atmosphere, reaction temperature, and WHSV on dehydration of glycerol over the Cu/SiO2 catalyst. In comparison with pure H2 or pure N2 atmosphere, the Cu/SiO2 catalyst exhibited significantly higher activity and selectivity for acetol under the mixed atmosphere of 5% H2-95% N2. Under the mixed atmosphere, Cu/SiO2 showed a slower deactivation rate compared with N2 atmosphere and a more proper hydrogenation than that under H2 atmosphere. Under the optimal reaction conditions of 220 oC, WHSV of 0.08 h-1, and ambient 5%H2/N2 pressure, glycerol conversion and selectivity for acetol can be as high as 98.8% and 84.6%, respectively.

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Effects of Bi on the Catalytic Performance of MoVO/AlPO4 Catalyst for Selective Oxidation of Isobutene WANG Xitao, WANG Fen, JIANG Shi, ZHONG Shunhe* 2011, 32 (2):  352-356.  DOI: 10.3724/SP.J.1088.2011.01009 Abstract ( 3265 )   [Full Text(HTML)] () PDF (569KB) ( 948 )   MoVO/AlPO4 and MoVBiO/AlPO4 catalysts have been prepared by the sol-gel method. The effects of Bi on surface acidity, distribution of active species, V5+/V4+ ratio, crystalline phase, and catalytic performance for selective oxidation of isobutene to methacrolein were investigated. The catalysts were characterized by X-ray diffraction, FT-Raman spectroscopy, temperature programmed reduction and X-ray photoelectron spectroscopy. The results showed that the addition of Bi at a proper amount obviously improves the catalytic performance of catalyst for selective oxidation of isobutene. Methacrolein selectivity is elevated from 29.1% to 75.2% with the increase of Bi/V ratio from 0 to 0.5. The surface acidity, crystalline phase, and dispersion of molybdenum and vanadium oxides species are responsible for the catalytic properties of the MoVBiO/AlPO4 catalyst, which are especially related to the V5+/V4+ ratio on the surface.

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Influence of 2'-Substituent in the Nucleosides on Burkholderia cepacia Li-pase-Catalyzed Regioselective Acylation WANG Zhaoyu1, 2,*, ZONG Minhua2 2011, 32 (2):  357-361.  DOI: 10.3724/SP.J.1088.2011.00901 Abstract ( 2667 )   [Full Text(HTML)] () PDF (660KB) ( 913 )   The influence of 2'-differing substituent in the nucleosides on 3'-OH regioselective acylation catalyzed by Burkholderia cepacia lipase was investigated. The results revealed that the dominant products in the Burkholderia cepacia lipase-catalyzed acylation proved to be 3'-O-esters and the 3'-regioselectivity increased with the elongation of the aliphatic chain of the acyl donors. Burkholderia cepacia liapse displayed excellent 3'-regioselectivity (89%–98%) in the decanoylation of nucleoside analogs possessing 2'-substitute (such as H, F, Cl, and Br), while low 3'-regioselectivity (69%–74%) to the OH and OCH3 substitute in 2'-position.

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Synthesis of Hierarchical HZSM-5 Microspheres without Second Template and Their Application in Methane Dehydroaromatization YANG Jianhua, YU Suxia, HU Huiye, CHU Naibo, LU Jinming, YIN Dehong, WANG Jinqu 2011, 32 (2):  362-367.  DOI: 10.3724/SP.J.1088.2011.00937 Abstract ( 3603 )   [Full Text(HTML)] () PDF (1074KB) ( 1159 )   Hierarchical ZSM-5(ZSM-5-HW) microspheres were synthesized by controlling the hydrothermal conditions without any secondary template. The ZSM-5-HW microspheres with a diameter range of 10–15 μm were constructed by many rod-shaped crystals. N2 adsorption at –196 oC revealed that the ZSM-5-HW zeolite is of both micropore and mesopore structure. The hierarchical Mo/HZSM-5-HW catalyst exhibited higher catalytic activity and stability in methane dehydroaromatization. The initial CH4 conversion and the highest benzene yield were 18.5% and 9.5%, respectively, which are better than that of the conventional Mo/HZSM-5 catalyst. The CH4 conversion and benzene yield was kept at 10.2% and 5.5%, respectively, after running the reaction for 24 h.

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Influence of Preparation Methods on Catalytic Performance of Double Mesoporous Co-Based Catalysts for Fischer-Tropsch Synthesis WANG Jungang1,2, LI Debao1,*, HOU Bo1, JIA Litao1 , JIA Lihong1,2, SUN Zhiqiang3, LIU Bin3, GUO Jingang4, REN Runhou4, SUN Yuhan1,5,* 2011, 32 (2):  368-373.  DOI: 10.3724/SP.J.1088.2011.01003 Abstract ( 3078 )   [Full Text(HTML)] () PDF (773KB) ( 841 )   A series of cobalt-based catalyst samples supported on double mesoporous MCM-41 for Fischer-Tropsch synthesis (FTS) were prepared using three methods, incipient-wetness impregnation (IWI), vapor-induced hydrolysis (VIH), and excessive impregnation (EI). The catalyst samples were characterized by N2 physisorption, X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR) and Raman spectroscopy. The N2 physisorption results showed that the samples prepared by IWI and VIH retained the double mesoporous character, and the cobalt particles were mainly located in the pore. The FTS results showed that the reducibility and dispersion of active species of the samples prepared by IWI and EI were very high. The catalyst prepared by IWI had the smallest Co3O4 crystallite size and the highest dispersion and showed higher FTS activity, lower CH4 selectivity and higher C5+ selectivity.

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Preparation of Supported Nano-gold Catalyst by Adsorption Column Chromatography ZHAI Xinlei, XU Jinguang*, XU Xiufeng, ZOU Xuhua, QI Shixue, QI Caixia, AN Lidun 2011, 32 (2):  374-378.  DOI: 10.3724/SP.J.1088.2011.01004 Abstract ( 4025 )   [Full Text(HTML)] () PDF (707KB) ( 1089 )   A new method called adsorption column chromatography for the preparation of supported nano-gold catalysts was proposed. Au/Al2O3 was used as the model catalyst, and low-temperature CO oxidation was used as the model reaction. Effects of pH value of gold precursor solution, liquid-to-solid ratio of the gold precursor solution to the support, specific surface area of the support, and competition adsorbates such as water, ethanol, isopropanol, and acetone on the nano-structure of the gold catalyst were investigated. The optimal conditions are the pH value of gold precursor solution of 9, the liquid-to-solid ratio of 6:1, and acetone as the preferential adsorbate. Gold particles on the prepared Au/Al2O3 catalyst are well distributed and about 5 nm in diameter. The temperature for CO complete conversion is -25 oC. The specific surface area of Al2O3 has great impact on the Au/Al2O3 catalyst. The lower the polarity of the preferential adsorbate, the better the distribution of gold particles on the support. This method can improve the utilization ratio of gold and effectively remove toxic chlorine ions, and therefore it provides an effective way for the large-scale preparation of gold catalysts.

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Preparation of Mesoporous Alumina and Its Application in Dehydration of Methanol to Dimethyl Ether NIE Renfeng, WANG Junhua, FEI Jinhua, HOU Zhaoyin*, ZHENG Xiaoming 2011, 32 (2):  379-384.  DOI: 10.3724/SP.J.1088.2011.01008 Abstract ( 3653 )   [Full Text(HTML)] () PDF (500KB) ( 1233 )   Ordered mesoporous alumina was synthesized by the homogeneous precipitation method from aqueous Al(NO3)3·9H2O solution using cationic cetyltrimethylammonium bromide as template. Characterization results showed that the surface area, average pore diameter, and pore volume of the calcined mesoporous alumina are 179.8 m2/g, 5.4 nm and 0.3 cm3/g, respectively. Over the mesoporous alumina, the space time yield of dimethyl ether (DME) in methanol dehydration reaches 15.4 g/(g·h) at 280 oC and 30 h−1 with 90.2% methanol conversion. The activity of the mesoporous alumina samples for methanol dehydration to DME was compared. The detected activity for methanol dehydration strongly depends on the surface acid density of the alumina.