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Chinese Journal of Catalysis
2010, Vol. 31, No. 8
Online: 30 August 2010


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Prof. Delomon in his article on pages 859–871 shows how the activity is controlled in inorganic solid catalysts and enzymes. In solid catalysts, the activating molecule, dissociated by the donor, creates active sites. In enzymes, a molecular species adsorbed by the allosteric part, controls the prosthetic site. Will conceptual bridges between these mechanisms help develop new solid materials with catalytic properties approaching those of the enzymes developed by nature?

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Are Solid Catalysts Successfully Emulating Enzymes? Bernard DELMON 2010, 31 (8):  859-871.  DOI: 10.1016/S1872-2067(09)60088-7 Abstract ( 2965 )   [Full Text(HTML)] () PDF (3005KB) ( 1187 )   In many aspects, similitude exists between man-made catalysts and enzymes. Can scientific insight into this similitude stimulate new research directions in catalysis? More precisely, can the understanding of the mechanisms of activity control in enzymes suggest new advances for man-made catalysts? Indeed, it is already possible to design catalysts with (i) new structures (e.g. presence of several phases) and (ii) a better balance between the roles of the different components. The ambition is to keep the essential advantages of solids as catalysts, in particular robustness, easy separation from products, and tolerance to high temperatures, while adding the advantages typical of enzymes, like more activity, allostery, and more precise control of selectivity, in particular enantioselectivity. The ambition is to build a bridge between robust man-made functional solids and fragile but extremely selective enzymes. For that, results from a line of the work in our group will be used.

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N-Heterocyclic Carbenes: Versatile Reagents for Nickel-Catalyzed Coupling Reactions GU Shaojin, NI Peng, CHEN Wanzhi* 2010, 31 (8):  875-886.  DOI: 10.1016/S1872-2067(09)60089-9 Abstract ( 3967 )   [Full Text(HTML)] () PDF (502KB) ( 1217 )   The chemistry of N-heterocyclic carbenes (NHCs) has grown rapidly in the past decade. NHCs are now important ligands in homogeneous catalysis that show better catalytic activities than the typical phosphines in a number of transition metal catalyzed organic transformations, especially in C-C/heteroatom bond formation reactions. Ni is a much cheaper metal and the most promising alternative to Pd, and is receiving increasing attention. In this article we summarize new developments in the catalytic applications of nickel-NHC complexes in coupling reactions that include typical cross couplings of organic halides with various organometallic reagents and reductive coupling reactions.

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Progress of the Study on the Synthesis and Catalytic Property of Noncrystalline Alloy Nanotubes DING Weiping*, GUO Xuefeng, MO Min, ZHU Yan, CHEN Yi 2010, 31 (8):  887-894.  DOI: 10.3724/SP.J.1088.2010.00714 Abstract ( 3401 )   [Full Text(HTML)] () PDF (3054KB) ( 1288 )   Binary noncrystalline alloy nanotubes M-B (M = Fe, Co, and Ni) were prepared using NaBH4 as the reducing agent for the reduction of transition metal ions located in the layer structure of lytropic liquid crystals of mixed nonionic-anionic surfactants. By adding P-, Co-, or Cu- containing compound during the preparation of Ni alloy samples, ternary noncrystalline alloy nanotube, i.e., NiPB, NiCuB, or NiCoB, can be obtained. It has been argued that the presence of the lytropic liquid crystals is the key for the formation of noncrystalline nanotubes. The reduction of transition metal ions located in the layer structure of the liquid crystal accompanied by the formation of H2 results in the cleavage and curl of the layer structure leading to the formation of nanotubes. The catalytic properties of some hydrogenation reactions have shown that the noncrystalline nanotubes are superior to the corresponding noncrystalline nanoparticles. Due to the well known unique prop-erties of the noncrystalline materials, it is expected that the noncrystalline nanotubes, as a new type of nanotubes, might possess exciting prospects for their future application.

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Progress in Reaction-Controlled Phase-Transfer Catalysis LI Jun, GAO Shuang*, XI Zuwei 2010, 31 (8):  895-911.  DOI: 10.3724/SP.J.1088.2010.00450 Abstract ( 3419 )   [Full Text(HTML)] () PDF (679KB) ( 2003 )   Reaction-controlled phase-transfer catalysis is a new catalytic system. This catalytic system is homogeneous during the reaction. After the reaction the catalyst becomes insoluble solid and precipitates from the reaction medium, so that the catalyst can be easily separated and reused. This paper presents recent progress made in reaction-controlled phase transfer catalysis for the epoxidation of olefins, oxidation of alcohols, hydroxylation, reductive carbonylation of nitroaromatics, esterification, and other reactions by us and other groups.

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Progress in Selective Catalytic Reduction of NOx by Hydrogen in Excess Oxygen WU Peng, YU Qing, YAN Jing-Jing, WU Guang-Jun, LI Lan-Dong, GUAN Nai-Jia 2010, 31 (8):  912-918.  DOI: 10.3724/SP.J.1088.2010.00461 Abstract ( 3488 )   [Full Text(HTML)] () PDF (489KB) ( 1203 )   Selective catalytic reduction of nitrogen oxide by hydrogen (H2-SCR) is a newly developed effective method for nitrogen oxides elimination. The characteristics and current developments of H2-SCR are reviewed. Special attention is laid on the oxide and zeolite supported Pt and Pd catalysts employed in H2-SCR reaction and the corresponding H2-SCR reaction mechanism. Finally, future research on H2-SCR is proposed.

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The Development of Cobalt-Based Catalysts for Fischer-Tropsch Synthesis SUN Yu-Han, CHEN Jian-Gang, WANG Jun-Gang, JIA Li-Tao, HOU Bo, LI De-Bao, ZHANG Juan 2010, 31 (8):  919-927.  DOI: 10.3724/SP.J.1088.2010.00540 Abstract ( 4619 )   [Full Text(HTML)] () PDF (1407KB) ( 2973 )   Fischer-Tropsch (F-T) synthesis is an important route to utilize fossil resources such as coal and natural gas. The key point is the control of catalyst selectivity, that is how to suppress methane formation and to improve distillate selectivity. In the past decade, Co-based F-T synthesis catalysts and related scale-up were investigated in our laboratory, including the relationship between cobalt dispersion, reducibility, and methane formation along with the hydrophobic modification and the core-shell structure. It was found that CH4 selectivity is correlated with the reducibility of cobalt, which depends on its particle size. Based on these, Co-based catalysts have been developed for the scale-up with the feature of low CH4 and high heavy hydrocarbon selectivity. Catalyst I is now subjected to the demo-plant of over 5 000 t/a, and Catalyst II (with much low CH4 selectivity) has operated for more than 8 000 h.

Research Briefing

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Catalytic Conversion of Cellulose to Ethylene Glycol over Tungsten Phosphide Catalysts ZHAO Guan-Hong, ZHENG Ming-Yuan, WANG Ai-Qin, ZHANG Tao 2010, 31 (8):  928-932.  DOI: 10.1016/S1872-2067(10)60104-0 Abstract ( 4300 )   [Full Text(HTML)] () PDF (505KB) ( 1805 )   Tungsten phosphide (WP) showed good activity in the selective conversion of cellulose to ethylene glycol (EG). At a H2 initial pressure of 6 MPa and temperature of 245 oC, EG yield reached 25.4 mol% over 20%WP/AC (activated carbon) and 46.0 mol% over 2%Ni-20%WP/AC, which demonstrated a remarkable synergy between Ni and WP.

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Self-Assembly of Ionic Liquids and Metal Complexes in Super-Cages of NaY: Integration of Free Catalysts and Solvent Molecules into Confined Catalytic Sites MA Yu-Bo, HE Yu-De, ZHANG Qing-Hua, SHI Feng, MA Xiang-Yuan, LU Liu-Jin, DENG You-Quan 2010, 31 (8):  933-937.  DOI: 10.1016/S1872-2067(09)60090-5 Abstract ( 3740 )   [Full Text(HTML)] () PDF (1063KB) ( 1155 )   The integration of a free metal complex, Pd(phen)2+, and a room temperature ionic liquid (IL) solvent molecule, 1-decyl-3-methyl imidazolium bromide, into a complete catalytically active site and confined in a NaY zeolite super-cage with an appropriate spatial arrange-ment was investigated. This integration was achieved through a molecular self-assembly method. A preliminary test of this catalyst system for the carbonylation of aniline to methyl phenyl carbamate indicated that far higher catalytic activity could be achieved (TOF increased from 3 000 to 23 000 h–1) with far lower amounts of the IL solvent and the Pd complex in comparison with a simple mixture of Pd(phen)Cl2/IL/NaY as the catalyst. This new system can also be applied to other areas of catalysis.

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A Novel Ce-P-O Catalyst for Selective Catalytic Reduction of NO with NH3 LI Fei, XIAO De-Hai, ZHANG Yi-Bo, WANG De-Qiang, PAN Xi-Qiang, YANG Xiang-Guang 2010, 31 (8):  938-942.  DOI: 10.1016/S1872-2067(09)60093-0 Abstract ( 3712 )   [Full Text(HTML)] () PDF (463KB) ( 1401 )   A novel Ce-P-O catalyst for the selective catalytic reduction of NO with NH3 was synthesized. The Ce-P-O catalyst was calcined at 500 °C and showed higher deNOx activity (NO conversion > 90%) within the temperature range of 300–500 °C and at GHSV = 20 000 h?1. The NO conversion was not significantly affected by the presence of H2O and SO2. By comparison with the commercial V-W-Ti catalyst, the Ce-P-O catalyst exhibited better resistance to deactivation due to K2O poisoning.

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Au Nanoparticles Supported on a Layered Double Hydroxide with Excellent Catalytic Properties for the Aerobic Oxidation of Alcohols WANG Liang, MENG Xiang-Ju, XIAO Feng-Shou 2010, 31 (8):  943-947.  DOI: 10.1016/S1872-2067(09)60091-7 Abstract ( 3874 )   [Full Text(HTML)] () PDF (679KB) ( 1568 )   Au nanoparticles supported on Mg-Al-layered double hydroxide (Au/LDH) were successfully prepared by ion-exchange and reduction. XRD patterns and TEM images indicate that the Au nanoparticles are highly dispersed on the LDH support, and that the layered structure remains intact during the preparation process. Interestingly, Au/LDH shows high catalytic activity for the aerobic oxidation of alcohols under mild conditions. For example, the conversion of 1-phenylethanol and selectivity for acetophenone was nearly 100% using molecular oxygen as an oxidant under atmospheric pressure at room temperature. The Au/LDH composite exhibits high catalytic stability during these reactions, and therefore, it has great potential for industrial application.

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Preparation and Quantitative Characterization of Nitrogen-Functionalized Multiwalled Carbon Nanotubes CHEN Chun-Lin, ZHANG Jian, WANG Rui, SU Dang-Sheng, PENG Feng 2010, 31 (8):  948-954.  Abstract ( 2608 )   [Full Text(HTML)] () PDF (2432KB) ( 1400 )   Nitrogen-doped multiwalled carbon nanotubes (MWCNTs) were produced by catalytic chemical vapor deposition. The surface and structural properties were investigated by transmission electron microscopy, nitrogen physisorption, thermogravimetry-differential scanning calorimetry, temperature-programmed oxidation (TPO) and X-ray photoelectron spectroscopy. The surface of the purified sample contained 4.2% nitrogen atoms and comprised pyridine, lactam, pyridine oxide, pyridone and pyrrol functional components. TPO results reveal the combustion kinetics of each nitrogen-containing functional group. The nitrogen atoms are incorporated within the graphitic structure to give a basic surface, which will play an important role in the investigation of catalysis and energy conversion. A convenient route to a closed cup-like carbon nanostructure applicable to field emission devices is also reported.

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Low-Temperature Hydrogenation and Dehydrogenation of 1,3-Cyclohexadiene on Pt/Ni Bimetallic Catalysts QI Sui-Tao, YU Wei-Ting, William W. LONERGAN, YANG Bo-Lun, CHEN Jing-Guang 2010, 31 (8):  955-960.  Abstract ( 3131 )   [Full Text(HTML)] () PDF (646KB) ( 1206 )   Pt-Ni bimetallic catalysts and their corresponding monometallic catalysts supported on γ-Al2O3 were prepared by incipient wetness impregnation and characterized by CO chemisorption. Their low-temperature activity for the hydrogenation and dehydrogenation of 1,3-cyclohexadiene (1,3-CHD) was tested at 308 K in a batch reactor using Fourier transform infrared spectroscopy. The Pt-Ni/γ-Al2O3 bi-metallic catalyst showed higher activity than either Pt/γ-Al2O3 or Ni/γ-Al2O3. We correlated the experimental results with density functional theory calculations of the binding energy for 1,3-CHD on the corresponding model surfaces. The correlation confirmed that bimetallic sur-faces with weaker cycloalkene binding energy generally showed higher hydrogenation activity.

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Mesoporous Carbon Supported Co-Mo and Ni-Mo Catalysts for Hydrodesulfurization SHI Guojun, ZHAO Yu, HUANG Yu’an, SHEN Jianyi* 2010, 31 (8):  961-964.  Abstract ( 3287 )   [Full Text(HTML)] () PDF (461KB) ( 1301 )   Mesoporous carbons (CMC) have larger average pore diameters and possess larger surface areas and pore volumes than traditional activated carbons (AC). Co-Mo/CMC and Ni-Mo/CMC catalysts were prepared by impregnation in the presence of a chelating agent and they exhibited much better porous properties than their AC supported counterparts. Accordingly, the CMC supported Co-Mo and Ni-Mo catalysts showed higher activities than the AC supported catalysts for the hydrodesulfurization (HDS) of organic sulfides. More importantly, Co-Mo/CMC was much more active than commercial Co-Mo/γ-Al2O3 for the HDS of thiophene in a model gasoline. Ni-Mo/CMC was sig-nificantly more active than commercial FH-98 for the HDS of dibenzothiophene in a model diesel.

Research papers

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Controlled Ring-Opening Polymerization of ε-Caprolactone Catalyzed by a Rare Earth Schiff-Base Complex NI Xufeng#, ZHU Weiwei, SHEN Zhiquan* 2010, 31 (8):  965-971.  DOI: 10.1016/S1872-2067(10)60096-4 Abstract ( 3801 )   [Full Text(HTML)] () PDF (643KB) ( 933 )   Lanthanide Schiff-base complexes with the formula [3,5-tBu2-2-(O)C6H2CH=NC6H5]3Ln(THF) (Ln = Sc, Y, La, Nd, and Gd) were synthesized by the metathesis reaction of anhydrous LnCl3 with a Schiff-base sodium salt in good yields (> 80%). The complex containing a neodymium center was characterized by X-ray diffraction and the structure around the neodymium atom could be described as a pentagonal bipyramid. The ring-opening polymerization (ROP) of ε-caprolactone (CL) was successfully carried out using the lanthanide Schiff-base complexes as catalysts, and the neodymium complex leads to a controlled ROP of CL. The influence of the reaction conditions on the monomer conversion, molecular weight, and molecular weight distribution of the resultant polymers was investigated. The polymerization rate was first-order with respect to the monomer concentration. End-group analyses of the oligomer of CL showed that the polymerization underwent a coordination-insertion mechanism.

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Experimental Conditions for Valid Langmuir-Hinshelwood Kinetics WANG Dezheng* 2010, 31 (8):  972-978.  DOI: 10.1016/S1872-2067(10)60103-9 Abstract ( 5408 )   [Full Text(HTML)] () PDF (1008KB) ( 1623 )   Users of Langmuir-Hinshelwood kinetics often neglect that it invokes the pseudo-steady state hypothesis (PSSH) for all adsorbed species, and they do not check that the PSSH is validly used. However, with solid catalyzed reactions, the validity of the PSSH must often be based on the concentration of active sites being very small. With a high site concentration catalyst, the PSSH would be incorrect for adsorbates with significant coverages, which would make the deduced kinetic parameters lose their physical meaning and be only the parameters of curve fitting. It is estimated that many catalysts do not meet the criterion for their site concentration to be less than one-tenth the highest reactant concentration.

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Carbon Nanofiber-Supported Ru Catalysts for Hydrogen Evolution by Ammonia Decomposition DUAN Xue-Zhi, ZHOU Jing-Hong, QIAN Gang, LI Ping, ZHOU Xing-Gui, CHEN De 2010, 31 (8):  979-986.  DOI: 10.1016/S1872-2067(10)60097-6 Abstract ( 3534 )   [Full Text(HTML)] () PDF (778KB) ( 1318 )   Carbon nanofibers (CNFs) with fish-bone graphene alignment and carbon nanotubes (CNTs) were used to support ruthenium for ammonia decomposition. The Ru nanoparticles on the CNF supports are more active than those on CNT supports. The Ru particle size was adjusted by changing the Ru loading or by introducing oxygen containing groups onto the CNF surface. The site activity increases when the Ru crystal size increases. The oxygen groups on the CNFs have a remarkable effect on ammonia decomposition over the Ru nanoparticles. On identically sized Ru crystals, oxygen on the CNFs clearly enhances ammonia decomposition over the Ru/CNFs.

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Synthesis of Dimethyl Ether via Methanol Dehydration over Combined Al2O3-HZSM-5 Solid Acids ZHANG Liwei, WANG Junhua, WU Pei, HOU Zhaoyin, FEI Jinhua*, ZHENG Xiaoming 2010, 31 (8):  987-992.  DOI: 10.1016/S1872-2067(10)60098-8 Abstract ( 2971 )   [Full Text(HTML)] () PDF (1575KB) ( 1405 )   Combined Al2O3-HZSM-5 solid acids were prepared and used for methanol dehydration to dimethyl ether (DME) in a fixed-bed reactor. The physicochemical properties of the combined solid acids were characterized by X-ray diffraction, field emission scanning electron microscopy, N2 adsorption, and NH3 temperature-programmed desorption. Al2O3 was highly dispersed in Al2O3-HZSM-5 after impregnation (Al2O3-HZSM-5-IM), while a layered Al2O3-covered HZSM-5 structure solid acid was synthesized via chemical precipitation (Al2O3-HZSM-5-CP). Both the combined Al2O3-HZSM-5 solid acids prepared by impregnation and chemical precipitation have a higher surface area and more meso- and macropores. The combined Al2O3-HZSM-5 solid acids exhibit higher methanol dehydration activity than pure Al2O3 and it possesses higher stability than pure HZSM-5 at a lower temperature (235 ?C) and a higher LHSV (30 h?1). The stable DME productivities for Al2O3-HZSM-5-IM and Al2O3-HZSM-5-CP at 235 ?C reached 12.7 and 13.5 g/(g•h), respectively.

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Ethylbenzene Dehydrogenation in the Presence of CO2 over MCF-Supported Vanadium Oxide Catalysts LI Chun-Guang, MIAO Chang-Xi, NIE Ying-Ying, LE Ying-Hong, GU Song-Yuan, YANG Wei-Min, HUA Wei-Ming, GAO Zi 2010, 31 (8):  993-998.  DOI: 10.1016/S1872-2067(10)60099-X Abstract ( 3251 )   [Full Text(HTML)] () PDF (474KB) ( 1380 )   A series of vanadia catalysts supported on mesocellular silica foam (MCF) with a V content ranging from 2% to 10% were studied with respect to their performance in the dehydrogenation of ethylbenzene (EB) to styrene in the presence of CO2. The structural and textural characterization of these catalysts was done using N2 adsorption, X-ray diffraction, and temperature-programmed reduction. These catalysts were found to be effective for the dehydrogenation reaction and the 6%V/MCF catalyst showed the highest activity. The MCF-supported vanadia catalysts exhibited far higher activity than their conventional V/MCM-41 counterparts, which can be attributed to the higher reduci-bility and better diffusion of reactants and products in the former catalysts. A higher conversion was obtained during EB dehydrogenation with CO2 than with N2. This is due to the oxidative dehydrogenation of EB with the help of oxygen that originates from CO2 as well as the coupling of EB simple dehydrogenation with the reverse water-gas shift reaction.

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Modeling of Esterification in a Batch Reactor Coupled with Pervaporation for Production of n-Butyl Acetate ZOU Yun, TONG Zhang-Fa, LIU Kun, FENG Xian-She 2010, 31 (8):  999-1005.  DOI: 10.1016/S1872-2067(10)60100-3 Abstract ( 2846 )   [Full Text(HTML)] () PDF (467KB) ( 965 )   A mathematical model for esterification in a batch reactor coupled with pervaporation to describe a simultaneous reaction and water removal from the reactor was developed. The permeation of all components in the reaction mixture and their non-ideal thermodynamic behavior were taken into account. The esterification of acetic acid with n-butanol for the production of n-butyl acetate integrated with a poly(vinyl alcohol) pervaporation membrane was selected as the model system for this study. The validity of the model was tested by comparing the calculated results with experimental data reported in the literature. The results show that the esterification is facilitated by water removal using pervaporation, which accelerates the rate of ester formation. A parametric study was carried out to evaluate the effects of operating conditions on the performance of the pervaporation-coupled esterification reactor and this included temperature, initial composition of the reactants, membrane area relative to the reactor’s size, and catalyst concentration. Based on these results, suitable operating conditions for the mem-brane-integrated reaction process are discussed.

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Effects of Preparation Methods on the Catalytic Performance of LaMn0.8Mg0.2O3 Perovskite for Methane Combustion ZHU Linlin, LU Guanzhong*, WANG Yanqin, GUO Yun, GUO Yanglong 2010, 31 (8):  1006-1012.  DOI: 10.1016/S1872-2067(10)60101-5 Abstract ( 3173 )   [Full Text(HTML)] () PDF (625KB) ( 947 )   A perovskite-type composite oxide, LaMn0.8Mg0.2O3, was prepared by five methods, i.e., glycine-nitrate, sol-gel, co-precipitation, combustion synthesis, and hydrothermal treatment. The composites were characterized by X-ray diffraction, Fourier transform infrared spec-troscopy, H2-temperature-programmed reduction, and N2 adsorption-desorption isotherms. The catalytic activity of LaMn0.8Mg0.2O3 toward methane combustion was evaluated. The results show that the different preparation methods and calcination temperatures greatly influence the textural structure, crystallite size, and different oxygen species within the LaMn0.8Mg0.2O3 perovskite material. The perovskite catalyst synthesized by the glycine-nitrate method and calcined at 700 °C shows the best activity for methane combustion among the tested materials. Its T50 (the reaction temperature at which 50% CH4 is converted) is only ~440 °C. This good catalyst performance can be attributed to the small crystallite size (12.4 nm), larger surface area (18.6 m2/g), and high concentration of surface Mn4+ cations, which creates more flexible and reactive surface oxygen species.

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Formation of Periodic Arrays of O Vacancy Clusters on Monolayer FeO Islands Grown on Pt(111) MA Teng, FU Qiang#, YAO Yunxi, CUI Yi, TAN Dali, ZHAI Runsheng, BAO Xinhe* 2010, 31 (8):  1013-1018.  DOI: 10.1016/S1872-2067(10)60102-7 Abstract ( 3004 )   [Full Text(HTML)] () PDF (3868KB) ( 1137 )   The structural evolution of a Pt surface with 0.4 monolayer (ML) subsurface Fe on annealing in 1.1 × 10?7 kPa O2 was studied by scanning tunneling microscopy and X-ray photoelectron spectroscopy. When the annealing temperature was 600 K, only dissociative adsorption of O2 occurred, which induced the local restructuring of surface regions. At 750 K, subsurface Fe atoms segregated onto the surface and were oxidized. When the annealing temperature was increased to 850 K, well defined monolayer FeO islands with periodic arrays of defects were formed. The defects were located at the hexagonal closest packed sites (fcc) of FeO Moiré unit cells and were either single oxygen vacancies or multiple oxygen vacancies consisting of six missing O atoms. The formation of periodic defects on monolayer FeO islands may be a way to construct active sites on Pt-Fe model catalysts.

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Preparation of OMS-2/Cordierite Monolithic Catalysts and Their Catalytic Performance for Dimethyl Ether Combustion NA Xiuhui, YU Lin*, SUN Ming, DIAO Guiqiang, YANG Xiaqing, SHI Litao, PAN Jifei 2010, 31 (8):  1019-1024.  DOI: 10.3724/SP.J.1088.2010.91106 Abstract ( 4774 )   [Full Text(HTML)] () PDF (1293KB) ( 1003 )   Manganese oxide octahedral molecular sieve (OMS-2)/cordierite monolithic catalysts were prepared by a coating method using poly(vinyl alcohol) (PVA) or poly(ethylene glycol) (PEG) as the binders. The catalysts were characterized by thermogravimetry-differential thermal analysis, scanning electron microscopy, X-ray diffraction, H2 temperature-programmed reduction (H2-TPR), and O2 tempera-ture-programmed desorption (O2-TPD). The catalytic activity of the catalysts in dimethyl ether (DME) combustion was evaluated. OMS-2 could be loaded on the cordierite with good adhesion stability by the coating method. OMS-2 was in a cluster form and was homogeneously dispersed on the surface of the support. The O2-TPD and H2-TPR results showed that the monolithic catalysts were rich in facile lattice oxy-gen and can activate oxygen and be easily reduced by H2, which led to excellent performance in the DME catalytic combustion. The catalyst with 3% PVA-1799 showed the highest catalytic activity for DME combustion with a light-off temperature (T10) of 169 oC and a complete combustion temperature (T90) of 243 oC. The T90 was raised to 302 oC over the used catalyst after being recalcined at 550 oC for 5 h, but the catalytic activity remained stable after nearly 100 h on stream with recycling 9 times. This indicated that the catalyst was recyclable.

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Nanoporous Carbon Supported MnOx Catalysts for Oxidation of Benzyl Alcohol LIU Gang, ZHANG Xiu-Yan, XU Yue, ZHANG Min, JIA Ming-Jun, ZHANG Wen-Xiang, WU Tong-Hao 2010, 31 (8):  1025-1030.  DOI: 10.3724/SP.J.1088.2010.00434 Abstract ( 2609 )   [Full Text(HTML)] () PDF (570KB) ( 1653 )   A series of nanoporous carbon (NC) supported MnOx catalysts (MnOx/NC) prepared by conventional wet impregnation were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption-desorption, and H2-temperature programmed reduction. They were tested as catalysts for the oxidation of benzyl alcohol using air as the oxygen source. The influence of various factors such as Mn loading, calcination temperature, and reaction conditions on their catalytic performance was investigated. The 10%MnOx/NC catalyst exhibits relatively high activity (80.4% conversion of benzyl alcohol after 4 h reaction), which is much higher than that of the catalyst prepared using conventional activated carbon as the support. The excellent catalytic activity of MnOx/NC can be mainly assigned to the formation of highly dispersed and easily reduced MnOx species on the surface of the NC support.

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Oxidative Degradation of Organic Pollutants Catalyzed by Trace Manganese(II) Ion in Sodium Bicarbonate Solution XU Ai-Hua, SHAO Ke-Jie, WU Wen-Li, FAN Jing, CUI Jin-Jiu, YIN Guo-Chuan 2010, 31 (8):  1031-1036.  DOI: 10.3724/SP.J.1088.2010.00448 Abstract ( 3243 )   [Full Text(HTML)] () PDF (557KB) ( 1301 )   Catalytic degradation of organic pollutants in a sodium bicarbonate solution with Mn2+ ion (0.004–0.1 mmol/L) as the catalyst has been studied using H2O2 as the oxidant. Complete decoloration of methylene blue was achieved in 180 min with 44.0% chemical oxidation demand removal at 25 oC at the NaHCO3, MnCl2 and H2O2 concentrations of 25, 0.1, and 100 mmol/L, respectively. The total organic carbon measurement indicated that 13.8% of the carbon was mineralized. The Mn2+/HCO3? + H2O2 system also showed high ability for oxidative degradation of methyl orange, rhodamine B, and even landfill leachate. The analysis of UV-Vis spectroscopy and reaction kinetics indicated that the MnIV=O intermediate is the key active species in methylene blue degradation.

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Photocatalytic Oxidation of Benzene on Nano-crystalline Mg-Al-HT/TiO2 Heterocompounds CHEN Wei, LI Danzhen*, HE Shunhui, SHAO Yu, HUANG Yan, FU Xianzhi* 2010, 31 (8):  1037-1043.  DOI: 10.3724/SP.J.1088.2010.00442 Abstract ( 2938 )   [Full Text(HTML)] () PDF (1889KB) ( 1251 )   Mg-Al hydrotalcite-like compounds (Mg-Al-HT) with Mg/Al molar ratio of 2 have been successfully synthesized by a supersaturated precipitation method and then mixed with a titania-sol to prepare nano-crystalline Mg-Al hydrotalcite-like compounds/TiO2 (Mg-Al-HT/TiO2) heterocompound photocatalysts by a hydrothermal method. The structure and components, Brunauer-Emmett-Teller spe-cific surface area, and photoresponse of the photocatalysts were characterized by powder X-ray diffraction, transmission electron micros-copy, field-emission scanning electron microscopy, N2 sorption, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic activity of the nano-crystalline Mg-Al-HT/TiO2 heterocompound photocatalysts for degradation of benzene was superior to that of single TiO2 or Mg-Al-HT under 365 nm light irradiation. The Mg-Al-HT/TiO2 heterocompound photocatalysts had higher stability. The electron paramagnetic resonance (EPR) technique was used to acquire the spin trapped-EPR spectra of the active species in the photocatalytic reac-tion. The possible photocatalytic reaction mechanism was also proposed.

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Palladium Catalyzed Carboxylation of 1,3-Butadiene to Methyl 3-Pentenoate WANG Lian-Di, WU Xiao-Wei, HE Wei, LIU Zi-Shuang, YU Zheng-Kun 2010, 31 (8):  1044-1048.  DOI: 10.3724/SP.J.1088.2010.00456 Abstract ( 3210 )   [Full Text(HTML)] () PDF (484KB) ( 1137 )   Palladium salts with N-heterocyclic ligand or biphosphine ligand were used as the catalysts for the carboxylation of 1,3-butadiene with carbon monoxide in methanol to methyl 3-pentenoate, which is one of the key reactions in Altam process for production of ?-caprolactam. The combination of Pd(OAc)2 with 2,6-bis(3,5-dimethylpyrazol-1-yl)pyridine exhibited moderate catalytic activity under the optimized conditions (150 ºC, p(CO) = 6.0 MPa, 6 h), reaching 78.8% conversion of 1,3-butadiene and 92.2% selectivity for the target product (TON = 226). Using Pd(OAc)2/(oxydi-2,1-phenylene)bis(diphenylphosphine) as the catalyst remarkably increased the reaction efficiency, achieving 90.4% conversion of 1,3-butadiene and 91.6% selectivity for the product (TON = 181). At temperature above 200 ºC, 1,3-butadiene underwent dimerization to form 4-vinyl-1-cyclohexene in 96% yield.

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Hydrogen Permeation in a Thin Pd-Cu Alloy Membrane Reactor for Steam Reforming of Ethanol ZHANG Xiao-Liang, WANG Wei-Ping, XIONG Guo-Xing, YANG Wei-Shen 2010, 31 (8):  1049-1053.  DOI: 10.3724/SP.J.1088.2010.00462 Abstract ( 3055 )   [Full Text(HTML)] () PDF (2179KB) ( 1029 )   Hydrogen permeation through a thin fcc-Pd0.9Cu0.1 alloy composite membrane was investigated with H2-Ar-C2H5OH- H2O mixtures for this modeling reaction over a range of temperature (250–500 °C) and pressure (160–310 kPa). The influence of temperature, feed pressure, feed flow rate, ratio of ethanol to steam, and hydrogen concentration of feed was examined under the operating conditions. Ethanol has inhibitive effect on hydrogen permeation performance through the membrane in comparison with that in pure hydrogen atmosphere. Moreover, hydrogen flux increased with increasing total mixture pressure and hydrogen concentration in the mixture feed but was not related to the ratio of ethanol to steam. Thus, the inhibitive influence of ethanol on hydrogen permeation was similar to that of steam under the same operating conditions. Although ethanol and steam can decrease hydrogen permeation, the hydrogen flux of membrane up to 11.3 m3/(m2•h) and hydrogen recovery over 62.5% were obtained in H2-Ar-C2H5OH-H2O (H2:Ar:(C2H5OH + H2O) volume ratio = 60:30:10) mixtures at 500 °C and 310 kPa. The membrane was stable without poisoning under ethanol-containing mixtures and would be suitable for the catalytic membrane reactor of steam reforming of ethanol to pure hydrogen production.

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Oxidative Dehydrogenation of Propane to Propene over Mesoporous Alumina-Supported Vanadium Oxide Catalyst WANG Yu, XIE Songhai, YUE Bin*, FENG Sujiao, HE Heyong* 2010, 31 (8):  1054-1060.  DOI: 10.3724/SP.J.1088.2010.00463 Abstract ( 2804 )   [Full Text(HTML)] () PDF (2019KB) ( 1277 )   Mesoporous alumina-supported vanadia catalyst (V/m-Al2O3) samples with different vanadium contents were prepared by the impregnation method and tested in the oxidative dehydrogenation of propane. The catalyst samples were characterized by N2 adsorption-desorption, transmission electron microscopy, X-ray powder diffraction, UV-Vis diffuse reflectance spectroscopy, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The results showed that the support possessed 2D hexagonal mesostructure, large surface area, and narrow pore size distribution. Suitable loading of vanadia led to high dispersion of vanadium species and weak acidity of the catalyst, which improved the propane conversion and propene selectivity. V/m-Al2O3 also exhibited better catalytic performance than the vanadia-incorporated mesoporous alumina prepared by a co-synthesis method and ?-Al2O3-supported vanadia by an impregnation method.

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Oxidant-Free Dehydrogenation of Alcohols over Hydrotalcite-Supported Palladium Catalysts CHEN Jing, ZHANG Qing-Hong, FANG Wen-Hao, WANG Ye, WAN Hui-Lin 2010, 31 (8):  1061-1070.  DOI: 10.3724/SP.J.1088.2010.00505 Abstract ( 4111 )   [Full Text(HTML)] () PDF (1595KB) ( 1230 )   Pd catalysts supported on various supports have been studied for the oxidant-free dehydrogenation of alcohols. The Pd catalyst loaded on hydrotalcite (HT), which is an acid-base bifunctional support, demonstrates superior benzyl alcohol conversion and benzaldehyde selectivity. Detailed studies using the Pd/HT catalyst reveal that the best performance can be obtained over the catalyst with w(Pd) = 0.32%–0.55%. The Pd/HT can be used repeatedly without significant deactivation and can efficiently catalyze the dehydrogenation of various alcohols including the substituted benzylic alcohols, 2-thiophenemethanol, α,β-unsaturated alcohols, and cyclic aliphatic alcohols. The characterization results show that the Pd(II) species over the HT are transformed into Pd nanoparticles or nanoclusters with mean size of 2.0–2.5 nm during the reaction. The highly dispersed Pd(II) species in the catalyst precursors can lead to the formation of smaller Pd nanoparticles, favoring the catalytic performance. We speculate that the basicity of the catalyst may promote the activation of the O-H bond of alcohol to form a Pd-benzyl alcoholate intermediate, which undergoes β-H abstraction by Pd nanoparticles, and the Brönsted acid sites on the catalyst surface may facilitate the release of H2 by the interaction with the formed hydride species on Pd nanoparticles.

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The Crystallization Process of MCM-49/ZSM-35 Composite Zeolites in a Mixed-Amine System XIE Sujuan1, LIU Kefeng1, 2, LIU Shenglin1, LIU Yong1, ZHANG Weiping1, 3, XU Longya1, 3, * 2010, 31 (8):  1071-1076.  DOI: 10.3724/SP.J.1088.2010.00510 Abstract ( 2529 )   [Full Text(HTML)] () PDF (1273KB) ( 855 )   The crystallization process of MCM-49/ZSM-35 composite zeolites in the Na2O-SiO2-Al2O3-CHA (cyclohexamine)-HMI (hexa-methyleneimine)-H2O system was investigated by X-ray diffraction, N2 adsorption, scanning electron microscopy, and Fourier transform infrared spectroscopy. The results showed that in the HMI-CHA system, pure phase MCM-49 was obtained first, then MCM-49/ZSM-35 composite zeolites were gradually formed with increasing ZSM-35 content upon the crystallization time, and finally pure phase ZSM-35 was produced. Moreover, the formation of ZSM-35 zeolite was based on the consumption of MCM-49 zeolite in this mixed-amine system.

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Copolymerization of Propylene and Polar Monomers by a New Ziegler-Natta Catalyst System with Diether as Internal Donor HUANG He1,2, ZHANG Liaoyun2, LI Huayi1, HU Youliang1,* 2010, 31 (8):  1077-1082.  DOI: 10.3724/SP.J.1088.2010.00520 Abstract ( 2743 )   [Full Text(HTML)] () PDF (473KB) ( 1191 )   The functionalization of polyolefins has been an area of scientific challenge and industrial importance for many years because the lack of polar groups in polyolefins significantly limits their applications. In all of the ways, copolymerization with polar monomers is the most efficient one to functionalize polyolefins. In this article, copolymerization of propylene with 10-undecen-1-ol and 10-undecenoic acid using triethylaluminum as the protection reagent has been performed in the TiCl4/MgCl2/diether/Al(C2H5)3 catalysis system. In the presence of both comonomers, activity of copolymerization decreases with the increase of comonomer in the feed, but the decadence of polymerization activity is less. With increasing polar monomer in the feed, the content of comonomer in copolymer increases. 10-Undecen-1-ol shows better performance, in terms of not only activity but also the comonomer content in copolymer. With increasing the content of comonomer in copolymer, both melting point and crystallize temperature of copolymers decrease. The polymerization temperature has less effect on po-lymerization activity and comonomer content in the copolymerization of propylene and 10-undecen-1-ol.

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The Cooperative Templating Effect of Organic Amine in the Ionothermal Synthesis of LTA Type Aluminophosphate Molecular Sieves PEI Renyan1,2, XU Yunpeng1,2, WEI Ying1,2, WEN Guodong 1,2, LI Keda1,2, WANG Lei1, MA Huaijun1, TIAN Zhijian1,3,*, LIN Liwu3 2010, 31 (8):  1083-1089.  DOI: 10.3724/SP.J.1088.2010.00701 Abstract ( 2658 )   [Full Text(HTML)] () PDF (1193KB) ( 1049 )   The LTA type aluminophosphate molecular sieve (AlPO4-42) was ionothermally synthesized by introducing organic amine into the 1-butyl-3-methylimidazolium bromide ([bmim]Br) ionic liquid. The as-synthesized products were characterized and the crystallization ki-netics was investigated. Thermal gravimetric analysis, nuclear magnetic resonance spectroscopy, and infrared spectroscopy demonstrated that the organic amine and the cation of the ionic liquid filled in the channels of the molecular sieve together. The introduced amine acted as the synergetic templates in a certain aggregated state according to the result of photoluminescence emission spectroscopy. The final products varied with the crystallization time, and the kinetic pathway was influenced by the amine concentration, which decreased with the growth of the crystal product during the crystallization. The inorganic materials reassembled around these aggregated templates when they exist in a high concentration to form sod or lta cages, resulting in the crystallization of cubic LTA framework.