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    Chinese Journal of Catalysis
    2012, Vol. 33, No. 10
    Online: 28 September 2012

    Cover:

    Hu and co-workers investigated the functions of the surface oxygen groups on an activated carbon catalyst in the hydroxylation of benzene. Adsorbed phenolic hydroxyl and quinone were proposed as the active sites for the hydroxylation. See the article on pages 16221630.

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    Table of Contents
    Table of Contents for Vol. 33 No. 10
    2012, 33 (10):  0-0. 
    Abstract ( 940 )   PDF (2060KB) ( 990 )  
    Summary
    Ceramics in Environmental Catalysis: Applications and Possibilities
    Nitin LABHSETWAR, P. DOGGALI, S. RAYALU, R. YADAV, T. MISTUHASHI, H. HANEDA
    2012, 33 (10):  1611-1621.  DOI: 10.1016/S1872-2067(11)60440-3
    Abstract ( 1982 )   [Full Text(HTML)] () PDF (341KB) ( 1261 )  
    Environmental catalysis has been steadily growing because of the advances in its scientific and engineering aspects, as well as due to the new environmental challenges in the industrial era. The development of new catalysts and materials is essential for new technologies for various environmental applications. Ceramics play important roles in various environmental applications including the identification, monitoring, and quantification of pollutants and their control. Ceramics have important applications as sensors and photocatalysts, and they are extensively used as catalyst carriers and supports. Many ceramics are being explored as catalysts for pollution control applications. Their low cost, thermal and chemical stability, and capability of being tailored make them especially attractive for pollution control applications. Although a wide variety of materials have been developed as catalyst supports, this area is still of interest with new or modified catalyst supports being frequently reported. It is of equal importance to develop new or modified processes for the loading of catalysts on specific supports. Applications like chemical looping combustion (CLC) and other catalytic combustion processes are raising the demands to a new scale. We have been working on the development of both new and modified support materials, including mesoporous materials without structural order for possible applications in CLC and other catalytic reactions. Successful attempts have been made in the modification of conventional γ-Al2O3 and improved synthesis processes for supporting perovskite type catalysts. Our research on environmental catalysis applications of ceramic materials and processes are also briefly discussed.
    Research papers
    Hydroxylation of Benzene by Activated Carbon Catalyst
    XU Jia-Quan, LIU Hui-Hui, YANG Rui-Guang, LI Gui-Ying, HU Chang-Wei
    2012, 33 (10):  1622-1630.  DOI: 10.1016/S1872-2067(11)60444-0
    Abstract ( 2461 )   [Full Text(HTML)] () PDF (471KB) ( 972 )  
    Phenol is widely used in industry. The hydroxylation of benzene to phenol can meet the increasing requirement for phenol and green chemistry. Commercial wood-based activated carbon was treated by different methods, including oxidation by nitric acid and hydrogen peroxide and thermal treatment at different temperatures, and used as the catalyst for the hydroxylation of benzene to phenol in acetonitrile using H2O2 as oxidant. The mechanism of the hydroxylation was also investigated. The activated carbon samples were characterized by Boehm titration, nitrogen adsorption, and X-ray photoelectron spectroscopy. The pH had a significant effect on the phenol yield. The effect of benzene adsorption was also investigated. Several model compounds with oxygen groups were used as catalysts for the hydroxylation of benzene. The reaction between phenolic hydroxyl and quinone on the surface of activated carbon was responsible for the hydroxylation of benzene to phenol when it activated H2O2 to form the hydroxyl radical. Activated carbon was an efficient and stable catalyst and a maximum phenol yield of 14.4% was obtained under the optimal reaction conditions.
    Temperature-Programmed Surface Reaction Study of Adsorption and Reaction of H2S on Ceria
    LIU Bing, XU Heng-Yong, ZHANG Ze-Hui
    2012, 33 (10):  1631-1635.  DOI: 10.1016/S1872-2067(11)60416-6
    Abstract ( 2265 )   [Full Text(HTML)] () PDF (539KB) ( 843 )  
    H2S adsorption and reaction on CeO2, TiO2, and γ-Al2O3 were studied by temperature programmed surface reaction (TPSR). Ceria had the best desulfidation ability. The pretreatment atmosphere affected H2S adsorption and reaction on ceria, and desulfidation efficiency increased in the order of inert atmosphere, reducing atmosphere, oxidizing atmosphere. H2S was first adsorbed on pretreated ceria at room temperature. On increasing the temperature in an Ar (99.99%) atmosphere, part of the H2S desorbed below 673 K, and another part reacted with the surface oxygen on ceria to produce sulfur and water below 473 K, and SO2 between 473 and 673 K, which further reacted with lattice oxygen and was transformed into sulfate above 673 K. The sulfate decomposed into SO2 again at 873 K. To avoid the complex regeneration, it is advisable to carry out desulfidation below 673 K when using ceria as adsorbent.
    Yb(OTf)3-Catalyzed Addition of 2-Methyl Azaarenes to Isatins via C–H Functionalization
    NIU Rui, YANG Shi-Ying, XIAO Jian, LIANG Tao, LI Xing-Wei
    2012, 33 (10):  1636-1641.  DOI: 10.1016/S1872-2067(11)60414-2
    Abstract ( 2579 )   [Full Text(HTML)] () PDF (409KB) ( 958 )  
    3-Substituted-3-hydroxy-2-oxindoles are rich in a range of biologically active natural products and pharmaceuticals and development of efficient methods to construct this key motif is of vital importance. Yb(OTf)3-catalyzed addition of 2- or 4-methyl azaarenes to isatins via C–H functionalization was developed. Moderate to good yields were obtained for various isatins and azaarenes. This method provides rapid protocol for the synthesis of biologically important azaarene-substituted 3-hydroxy-2-oxindoles in one step. The success of this reaction expands the synthetic utility of Lewis acid in the catalytic functionalization of sp3 C–H bonds in organic synthesis.
    Effect of Metal Additives on Structure and Properties of a Co/SiO2 Hydrogenation Catalyst
    XUE Jing-Jing, CUI Fang, HUANG Zhi-Wei, ZUO Jian-Liang, CHEN Jing, XIA Chun-Gu
    2012, 33 (10):  1642-1649.  DOI: 10.1016/S1872-2067(11)60434-8
    Abstract ( 1999 )   [Full Text(HTML)] () PDF (801KB) ( 946 )  
    The effects of metal additives (Zn, Fe, Cu, and Sn) on the properties and catalytic performance of a Co/SiO2 catalyst (prepared by a co-precipitation method) in the liquid-phase hydrogenation of ethyl lactate were investigated. The electronic properties and surface distribution of Co in the catalyst were significantly changed by incorporation of the additives. The particle size of the cobalt species was reduced, which strengthened the interaction between the cobalt particles and the silica support and decreased the reducibility of the catalyst. As a consequence, both ethyl lactate conversion and 1,2-propanediol selectivity decreased upon incorporation of the additives. Ethyl lactate conversion was related less to the size and surface area of the catalyst particles than to the distribution of the cobalt species and the reducibility of the catalyst.
    Two-Enzyme Coexpressed Recombinant Strain for Asymmetric Synthesis of Ethyl (R)-2-Hydroxy-4-phenylbutyrate
    SU Yu-Ning, NI Ye, WANG Jun-Chao, XU Zhi-Hao, SUN Zhi-Hao
    2012, 33 (10):  1650-1660.  DOI: 10.1016/S1872-2067(11)60436-1
    Abstract ( 2106 )   [Full Text(HTML)] () PDF (615KB) ( 914 )  
    (R)-2-Hydroxy-4-phenylbutyrate (HPBE) is an important chiral intermediate for the synthesis of angiotensin-converting enzyme (ACE) inhibitors. Asymmetric reduction of ethyl 2-oxo-4-phenyl-butyrate (OPBE) to (R)-HPBE using a recombinant strain can provide high enantioselectivity. Cofactor regeneration is a critical issue in the application of a recombinant strain. A carbonyl reductase gene (iolS) and a glucose dehydrogenase (GDH) gene from Bacillus subtilis were cloned. Recombinant IolS was purified using a Ni-NTA column and its enzyme activity properties were investigated. The purified IolS exhibited maximum activity at pH 6.0 and 30 oC, and the enzyme showed good thermostability below 40 oC. It retained over 75% of its activity in the acidic pH range of 5.5-7.0. Three coexpression strategies were used for the recombinant vectors. The recombinant E. coli strain containing polycistronic plasmid pET-G-T7-I showed excellent carbonyl reductase activity, and the specific activity of both IolS and GDH in the crude cell extract reached 1.5 U/mg. In the asymmetric reduction of OPBE by recombinant E. coli cells in aqueous system, the yield of (R)-HPBE reached over 99% with an enantiomeric excess of 99.5% at 10 g/L of OPBE within 15 h.
    An Efficient and Facile Procedure for Synthesis of Acetates from Alcohols Catalyzed by Poly(4-vinylpyridinium tribromide)
    Maryam HAJJAMI, Arash GHORBANI-CHOGHAMARANI, Masoomeh NOROUZI
    2012, 33 (10):  1661-1664.  DOI: 10.1016/S1872-2067(11)60441-5
    Abstract ( 1887 )   [Full Text(HTML)] () PDF (282KB) ( 916 )  
    Poly(4-vinylpyridinium tribromide) is an efficient catalyst for the conversion of various alcohols to their corresponding acetate derivatives with acetic anhydride. This method has some advantages such as mild reaction conditions, good to excellent yields, and ease of work-up.
    Fabrication and Photocatalytic Activity of Highly Crystalline Nitrogen Doped Mesoporous TiO2
    LIU 二Qiang, GUO Xiao-Ling, QIN Lei, SHEN Guo-Dong, WANG Xiang-Dong
    2012, 33 (10):  1665-1671.  DOI: 10.1016/S1872-2067(11)60437-3
    Abstract ( 2412 )   [Full Text(HTML)] () PDF (1774KB) ( 1160 )  
    Highly crystalline nitrogen doped mesoporous TiO2 photocatalysts were fabricated by the sol-gel method using tetrabutyl titanate as the Ti source, urea as the N source, and polyacrylamide (PAM) and polyethylene glycol (PEG) as the templates, and then by calcining in nitrogen and air. The photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy. When the mass ratio of PAM and PEG was 1:4, the sample prepared by calcining at 600 °C in nitrogen and 500 °C in air had the anatase phase and a mesoporous structure and high crystallinity. The average pore size, crystallite size, and specific surface area were 5.11 nm, 12.5 nm, and 110.8 m2/g, respectively. Nitrogen atoms were incorporated into the TiO2 lattice mainly as substitutional N and molecularly chemisorbed γ-N2, and a small amount of interstitial N. Nitrogen doping narrowed the band gap and allowed light absorption in the visible light region. Compared with undoped mesoporous TiO2, the absorption band edge of nitrogen doped samples exhibited a red shift and the light absorption intensity was increased. Photocatalytic degradation of methyl orange showed that the nitrogen doped mesoporous TiO2 had a higher photocatalytic activity than undoped mesoporous TiO2 under visible light.
    LED Irradiation of a Photocatalyst for Benzene, Toluene, Ethyl Benzene, and Xylene Decomposition
    JO Wan-Kuen, KANG Hyun-Jung
    2012, 33 (10):  1672-1680.  DOI: 10.1016/S1872-2067(11)60446-4
    Abstract ( 2136 )   [Full Text(HTML)] () PDF (387KB) ( 1192 )  
    Studies on the use of gas phase applications of light emitting diodes (LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous solutions. The present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania (N-TiO2) prepared by hydrolysis to decompose gaseous benzene, toluene, ethyl benzene, m-xylene, p-xylene, and o-xylene. Photocatalysts calcined at different temperatures were characterized by various analytical instruments. The degradation efficiency of benzene was close to zero for all conditions. For the other compounds, a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 units. However, the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps (blue and white LEDs). The highest degradation efficiency was observed with the use of a calcination temperature of 350 oC. The average degradation efficiencies for toluene, ethyl benzene, m-xylene, p-xylene, and o-xylene were 35%, 68%, 94%, and 93%, respectively. The use of blue- and white-LEDs, high light intensity, and low initial concentrations gave high photocatalytic activities for the photocatalytic units using visible-LEDs. The morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination temperature. The results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications, but the activity depends on the operational conditions.
    Preparation of Mesoporous TiO2 Spheres via Sol-Gel Assisted Hydrothermal Method Using Double Templates
    WANG Dian-Ping, LIU Shou-Xin
    2012, 33 (10):  1681-1688.  DOI: 10.3724/SP.J.1088.2012.20532
    Abstract ( 2089 )   [Full Text(HTML)] () PDF (1446KB) ( 1172 )  
    Mesoporous TiO2 (MS-TiO2) spheres were prepared by a sol-gel assisted hydrothermal method using double-surfactant (PEG and F127) as templates. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermal gravimetry, and N2 adsorption-desorption were used for catalyst structural characterization. Phenol was used as a model compound for photocatalytic activity test. The results showed that MS-TiO2 spheres with uniform diameter of 200–300 nm, which was composed by 15–20 nm of TiO2 crystals, can be obtained. Maximum specific surface area as high as 106.9 m2/g, together with pore diameter of 6.5–12.6 nm and pore volume of 0.21 cm3/g can be achieved under the optimum conditions. With increasing calcination temperature, specific surface area and pore volume of MS-TiO2 decreased, and pore diameter enlarged. Double templates can form a more stable spherical micelle, inhibit the growth and particle aggregation of TiO2 precursor and promote its self-assembly into spherical structure. MS-TiO2 prepared at 500 °C exhibited the highest activity with the phenol degradation of 86.4%, which is about 1.3 times that of TiO2 without templates.
    Immobilization of Vanadyl Acetylacetonate on Amino Functionalized Hollow Silica Nanospheres and Its Catalytic Performance for Selective Oxidation of Thioanisole
    WANG Peng, BAI Shi-Yang, LI Bo, YANG Qi-Hua
    2012, 33 (10):  1689-1695.  DOI: 10.3724/SP.J.1088.2012.20520
    Abstract ( 2041 )   [Full Text(HTML)] () PDF (530KB) ( 1032 )  
    Vanadyl acetylacetonate [VO(acac)2] was immobilized on amino functionalized mesoporous silica hollow nanospheres, as well as on amino functionalized SBA-15 (2D hexagonal mesostructure) and SBA-16 (cage-like mesostructure). All the heterogeneous catalysts exhibited high selectivity for sulfoxide (over 99.0%) in the selective oxidation of thioanisole under mild reaction conditions. The vanadium nanospheres exhibited higher turnover frequency than the counterparts of SBA-15 and SBA-16, which is attributed to the fact that the small nanoparticles would facilitate the diffusion of the products and reactants, as well as the exposure of catalytic active sites. The catalysts could be reused several times with little loss of their activity and selectivity.
    Conversion of Biomass-Derived Carbohydrates to Methyl Lactate Using Sn-MCM-41 and SnO2/SiO2
    LIU Zhen, FENG Gang, PAN Chun-Yan, LI Wang, CHEN Ping, LOU Hui, ZHENG Xiao-Ming
    2012, 33 (10):  1696-1705.  DOI: 10.3724/SP.J.1088.2012.20533
    Abstract ( 2243 )   [Full Text(HTML)] () PDF (1913KB) ( 1202 )  
    Biomass is a promising alternative for sustainable supply of precious intermediates and fine chemicals to the chemical industry. Lactic acid (2-hydroxypropanoic acid) and its related alkyl lactates are widely used in chemicals, food, pharmaceuticals, and cosmetic products. A study of the liquid-phase conversion of biomass-derived carbohydrates directly to methyl lactate catalyzed by Sn-MCM-41 and SnO2/SiO2 in subcritical methanol is presented. With glucose as substrate, methyl lactate yield reached 40.3% under the optimal reaction conditions. Fresh and used catalysts were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, infrared spectroscopy with pyridine adsorption, and NH3 temperature-programmed desorption techniques. Methyl lactate yield was closely related to reaction temperature, reaction time, and the acidic site amount of catalysts. The catalysts were active and can be reused without significant decrease in the catalytic activity after being used for five recycles. The mesoporous structure and acid sites of the reused catalysts did not change much and the leaching of Sn was less than 0.15%. They were easy and relatively rapid synthesis, operational simplicity, reusability, and safe handling.
    Theoretical Study of Selectivity of Ethylene Hydroformylation on Rh(111) and Rh@Cu(111) Surfaces
    MA Xiu-Fang, ZHAO Yong-Hui, SU Hai-Yan, LI Wei-Xue
    2012, 33 (10):  1706-1711.  DOI: 10.3724/SP.J.1088.2012.20617
    Abstract ( 2039 )   [Full Text(HTML)] () PDF (402KB) ( 756 )  
    Selectivity-determining steps for ethylene hydroformylation, i.e., ethyl hydrogenation versus CO insertion on Rh(111) and Rh@Cu(111) surfaces were investigated by density functional theory calculations. Compared with the Rh(111) surface, the Rh@Cu(111) surface decreases the hydrogenation barrier by 0.12 eV and more significantly the CO insertion barrier by 0.78 eV due to the ensemble and ligand effects. This result indicates that Rh@Cu(111) alloy catalyst can improve the selectivity of the hydroformylation.
    Growth and Interfacial Interaction of Cu on ZrO2(111) Thin Film
    HOU Jian-Bo, HAN Yong, PAN Yong-He, XU Qian, PAN Hai-Bin, ZHU Jun-Fa
    2012, 33 (10):  1712-1716.  DOI: 10.3724/SP.J.1088.2012.20640
    Abstract ( 1768 )   [Full Text(HTML)] () PDF (504KB) ( 865 )  
    The growth mode and interfacial interaction of Cu nanoparticles on the ordered ZrO2(111) thin film surfaces have been studied by low energy electron diffraction, synchrotron radiation photoemission spectroscopy, and X-ray photoelectron spectroscopy. The ZrO2(111) thin film was grown on Pt(111) using the molecular beam epitaxy technique. At room temperature, copper initially grows two-dimensionally on the ZrO2(111) thin film up to 0.15 monolayer (ML), followed by three-dimensional islanding. The binding energy of Cu 2p3/2 increases with decreasing the Cu coverage, owing to the contribution from both the initial-state and final-state effects. The interaction between Cu and ZrO2 leads to the charge transfer from Cu to the ZrO2 substrate, which causes the appearance of Cu(I) state. Above 1 ML, Cu becomes metallic state on ZrO2.
    Probing the Essential Catalytic Residues and Substrate Affinity in Thermophilic L-Arabinose Isomerase by Homology Modeling and Site-Directed Mutagenesis
    LI Gui-Xiang, XU Zheng, LI Sha, XU Hong
    2012, 33 (10):  1717-1723.  DOI: 10.3724/SP.J.1088.2012.20606
    Abstract ( 1930 )   [Full Text(HTML)] () PDF (715KB) ( 1050 )  
    The L-arabinose isomerase from Lactobacillus fermentum CGMCC2921 (named LFAI) was distinguished from other L-AIs by its outstanding thermostability, and was defined as a potential candidate for industrial D-tagatose production. By means of homologous modeling and structure analysis, some important amino acid residues influencing D-galactose isomerization of LFAI were selected and mutated. The results showed that when residues Q16, M311, K423, and Q438 mutated to alanine, the Km value of the mutant LFAI decreased. Among them, mutant enzyme M311A retained half of its original Km value, and the conversion rate for D-galactose raised approximately 20%. Furthermore, by comparing mutants K423R, K423N, K423A, and native LFAI, it was found that the side-chain length of residue K423 may determine the substrate affinity and D-galactose conversion rate of these mutated enzymes. Through computer molecular modeling, it was also found mutation M311A had an enhancement on hydrogen bonding with D-galactose, thus resulting in an enhancement on its substrate affinity and enzyme activity.
    Synthesis and Growth Mechanism of the Core-Shell SAPO-34/AlPO-18 Molecular Sieves
    ZHANG Lin, TIAN Peng, SU Xiong, FAN Dong, WANG De-Hua, LIU Zhong-Min
    2012, 33 (10):  1724-1729.  DOI: 10.3724/SP.J.1088.2012.20650
    Abstract ( 2353 )   [Full Text(HTML)] () PDF (871KB) ( 872 )  
    The core-shell molecular sieves comprised of SAPO-34 as core and AlPO-18 as shell were hydrothermally synthesized and characterized by X-ray diffraction, scanning electron microscopy (SEM), and ultra-high resolution field-emission scanning electron microscopy (FE-SEM) techniques. The SEM results show that the growth of the shell AlPO-18 nanocrystals with different orientations and compactness can be controlled by adjustment of the synthesis conditions such as core pretreatment, liquid to solid ratio, and growth number. The ultra-high resolution FE-SEM images confirm that the growth performance of the shell AlPO-18 is closely related to the surface microstructure of SAPO-34, indicating the mechanism that the microstructure on the external surface of the core directs the growth of the shell.
    Preparation of Hyperbranched Polyethyleneimine Composite Membrane Using Interfacial Polymerization Catalyzed by 4-Dimethylamiopryidine
    ZHANG Lin, LIN Sai-Sai, WEI Ping, CHENG Li-Hua, CHEN Huan-Lin
    2012, 33 (10):  1730-1735.  DOI: 10.3724/SP.J.1088.2012.20427
    Abstract ( 2014 )   [Full Text(HTML)] () PDF (1781KB) ( 1209 )  
    The promoting effect of 4-dimethylaminopyridine (DMAP) on the interfacial polymerization between trimesoyl chloride (TMC) and hyperbranched polyethyleneimine (PEI) was investigated. The solubility of DMAP in organic phase and aqueous phase was examined and the mass fraction of DMAP to PEI was optimized to 8%. Fourier transform infrared spectroscopy and scanning electron microscopy results showed that when catalyzed by DMAP, almost all the amino groups of PEI were cross-linked with TMC into amide groups, and thus a smooth and integrated layer was formed on the polysulfone support membrane. The rejection of PEI/TMC composite membrane against NaCl was improved to 85.4% as compared with 45.2%. Combined with the donating electron effects of 1-tertiary amine and 4-methylamino groups, the catalytic mechanism for DMAP in this PEI-based interfacial polymerization was proposed.
    Photo-Fenton Degradation of RhB over Nano-fibre Iron Oxides Interacted Montmorillonite under Visible Light Irradiation
    ZHANG Shi-Long, HU Xiao-Ming, WANG Xiao-Wei, LIANG Shi-Jing, WU Leng
    2012, 33 (10):  1736-1741.  DOI: 10.3724/SP.J.1088.2012.20756
    Abstract ( 1961 )   [Full Text(HTML)] () PDF (811KB) ( 938 )  
    Trinuclear Fe(III) acetate complex intercalated montmorillonite Fenton catalysts were successfully prepared by a facile ion exchange process. The obtained catalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy, X-ray absorption fine structure, and inductively coupled plasma-atomic emission spectrometry. The results showed that the montmorillonite’s surface area was greatly increased after the trinuclear iron cluster intercalated. A few amorphous nano-fibre iron oxides were anchored on the surface of the catalyst. The prepared catalyst exhibited high efficiencies for the degradation and mineralization of rhodamine B in the presence of H2O2 under visible light irradiation. Furthermore, the main active species in catalytic reaction process have been investigated. Based on the experimental results, a possible mechanism was discussed and proposed.