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Chinese Journal of Catalysis
2010, Vol. 31, No. 12
Online: 13 December 2010


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An ONIOM study at B3LYP and M05-2X levels was carried out by LI Yan et al. to investigate thiophene cracking in H-ZSM-5 and the effect of zeolite framework on the geometry, electronic structure and energy of the intermediates. With the background of ZSM-5 structure, the cover picture illustrates the polymerization and C–S bond cracking of two thiophene molecules. See the Article on pages 1419–1426.

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An ONIOM Study of Thiophene Cracking in a Brönsted Acidic Zeolite LI Yan1, GUO Wenping2, FAN Weibin1, QIN Zhangfeng1, WANG Jianguo1,* 2010, 31 (12):  1419-1426.  Abstract ( 2196 )   [Full Text(HTML)] () PDF (614KB) ( 1123 )   An ONIOM study at B3LYP and M05-2X level was carried out to investigate thiophene cracking in a Brönsted acidic zeolite and the effect of the zeolite framework on the geometry, electronic structure, and energy of the intermediates. The zeolite framework stabilized positively charged transition states and lowered the reaction barriers. The newly developed M05-2X functional performed much better than the popular B3LYP functional for describing non-bonded interactions between the reactants and the zeolite framework, which gave more accurate electronic structures and energy barriers. The rate determining barrier was that for electrophilic aromatic substitution (122.4 kJ/mol), while the subsequent C–S bond dissociation has a lower barrier (75.5 kJ/mol).

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Oxidation of Organic Compounds by Sulfonated Porous Carbon and Hydrogen Peroxide Arash SHOKROLAHI*, Abbas ZALI, Mohammad Hossein KESHAVARZ 2010, 31 (12):  1427-1432.  Abstract ( 2224 )   [Full Text(HTML)] () PDF (308KB) ( 1098 )   The oxidation of organic compounds by sulfonated porous carbon and H2O2 was studied at room temperature. Alkyl and aryl sulfides were oxidized to the corresponding sulfoxides or sulfones in excellent yields. Secondary alcohols were also converted to the corresponding esters/lactones and aldehydes to methyl esters in good yields. Moreover, aliphatic tertiary amines and substituted pyridines were oxidized to N-oxides.

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Polymerization of Fatty Acid Methyl Ester Using Acidic Ionic Liquid as Catalyst LIU Shiwei1, LI Lu1, YU Shitao1,*, XIE Congxia2, LIU Fusheng1, SONG Zhanqian1,3 2010, 31 (12):  1433-1438.  Abstract ( 2451 )   [Full Text(HTML)] () PDF (481KB) ( 1276 )   The polymerization of fatty acid methyl ester was investigated using biodiesel as the feed in the presence of a Brönsted-Lewis acidic ionic liquid (IL). A synergetic effect of Brönsted and Lewis acid sites enhanced the catalytic performance of the IL. 1-(3-Sulfonic acid)-propyl-3-methylimidazole chlorozincinate ([HO3S-(CH2)3-mim]Cl-ZnCl2, molar fraction of ZnCl2 was 0.67) was an efficient catalyst for the polymerization. The effects of catalyst amount, reaction temperature, and reaction time were investigated. The optimum conditions for the polymerization were: biodiesel 15 g, m(biodiesel):m(IL) = 15:1, reaction temperature 240 oC, and reaction time 6 h, which gave 63.2% yield of dimeric acid methyl ester. The reusability of the IL was good and after it was used five times, the dimeric acid methyl ester yield was still > 63%.

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Dehydrocyclization of Diphenylamine to Carbazole over Platinum-Based Bimetallic Catalysts Miroslav VLCKO1,*, Zuzana CVENGROSOVA1, Zuzana CIBULKOVA2, Milan HRONEC1 2010, 31 (12):  1439-1444.  Abstract ( 2401 )   [Full Text(HTML)] () PDF (299KB) ( 1104 )   Gas phase dehydrocyclization of diphenylamine (DPA) to carbazole over monometallic and bimetallic 0.4 wt% Pt-based catalysts in a fixed bed reactor was studied in the presence of hydrogen at a temperature of 550 oC. Alumina and carbon supported Pt catalysts showed very high initial activity (> 95%). The selectivity for carbazole over carbon supported Pt catalysts was slightly lower. Doping of the catalyst with potassium led to an increase in the selectivity for carbazole by 15%. Bimetallic Pt-Sn catalysts prepared by co-impregnation were less selective than catalysts prepared by successive impregnation. The selectivity for carbazole over bimetallic Pt-Sn catalysts prepared by successive impregnation was 75%, but their activity decreased with increased Sn loading. Highly active and reasonably selective catalysts were Ir-doped bimetallic Pt-based catalysts. The conversion of diphenylamine over Pt-Ir catalysts was above 98% and the selectivity for carbazole was nearly 55%, while the lifetime was much longer.

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Possible Role of Carboxyl and Imidazole Groups in the Catalysis of Pummelo Limonoid Glucosyltransferase M. R. KARIM*, F. HASHINAGA 2010, 31 (12):  1445-1451.  Abstract ( 1935 )   [Full Text(HTML)] () PDF (319KB) ( 968 )   Limonoid bitterness is a serious problem in the citrus industry worldwide. Limonoid glucosyltransferase is an enzyme that catalyzes the conversion of bitter limonoid into non-bitter limonoid glucoside while retaining the health benefit of limonoids in the juice. The immobilization of this enzyme in a column can solve the juice bitterness problem. More information about the catalytic residues of the en-zyme is needed in this immobilization process. Glutamate/aspartate, histidine, lysine, tryptophan, serine, and cysteine residues were chemi-cally modified to investigate their roles in the catalytic function of limonoid glucosyltransferase. Inactivation of the enzyme following modi-fication of carboxyl and imidazole moieties was a consequence of a loss in substrate binding and catalysis in the glucosyltransfer reaction. The modification of a single histidine residue completely destroyed the ability of limonoid glucosyltransferase to transfer the D-glucopyranosyl unit. Tryptophan seemed to have some role in maintaining the active conformation of the catalytic site. Lysine also seemed to have some direct or indirect role in this catalysis but the modification of serine and cysteine did not have any effect on catalysis. There-fore, we conclude that the carboxyl and imidazole groups contain amino acids are responsible for the catalytic action of the enzyme.

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Effect of Precursors on Catalytic Activity of Ru/MgO-CeO2 Catalyst for Ammonia Synthesis WANG Xiuyun, WANG Rong*, NI Jun, LIN Jianxin, WEI Kemei 2010, 31 (12):  1452-1456.  DOI: 10.3724/SP.J.1088.2010.00539 Abstract ( 2206 )   [Full Text(HTML)] () PDF (426KB) ( 1143 )   Ru/MgO-CeO2 catalysts were prepared by co-precipitation with different precursors, including K2RuO4, Ru(Ac)3, and RuCl3, the obtained catalysts were characterized by X-ray diffraction, X-ray fluorescence, N2 physisorption, temperature-programmed reduction, and CO chemisorption. The results showed that the ammonia synthesis activity of the Ru/MgO-CeO2 catalyst prepared with K2RuO4 was 16.0% at 10 MPa, 450 °C, and 10 000 h-1, which was higher than those obtained with the other two precursors. The turnover frequency (TOF) of the Ru/MgO-CeO2 catalyst prepared with K2RuO4 was higher than those obtained with the other precursors under the same reaction conditions. The influence of precursors and preparation methods on the structure and performance of the catalysts was studied. The ratio of Ru/MgO-CeO2 catalysts prepared with K2RuO4, Ru(Ac)3, and RuCl3 as precursors for ammonia synthesis turnover frequency is 1.33:1.05:1 under 10 MPa, 425 °C, and 10 000 h-1.

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Epoxidation of Olefins Catalyzed by Magnesium-Based Mixed Oxides with Hydrogen Peroxide LU Xinning, LIN Haiqiang, YUAN Youzhu* 2010, 31 (12):  1457-1464.  DOI: 10.3724/SP.J.1088.2010.00551 Abstract ( 2356 )   [Full Text(HTML)] () PDF (627KB) ( 882 )   A series of Mg-based mixed oxides MgM-n (M = Sn, Al, Ti, La, Ce, Zr; n = Mg/M atomic ratio) were prepared. The physicochemical properties of these mixed oxides were characterized by X-ray diffraction, N2-adsorption/desorption, CO2 temperature-programmed desorption, ultraviolet and visible diffuse reflectance spectroscopy, and electron spin resonance. The catalytic activity of MgM-n for the epoxidation of olefins was investigated with H2O2 as an oxidant. The results indicated that the catalytic performance and basicity of MgM-n mixed oxides were correlated to the type and doping amount of M species. The MgAl-4 and MgSn-4 samples showed a conversion and epoxide selectivity as high as 95% along with over 80% H2O2 efficiency for the epoxidation of styrene. However, MgSn-4 possessed lower surface basicity and more stable performance during consecutive reuse in comparison with MgAl-4. Moreover, MgSn-4 could catalyze the epoxidation of olefins of different structure with excellent performance. With the characteristic studies, it was presumed that such a superior performance of MgSn-4 could essentially be ascribed to the highly dispersed Sn4+ species and its unique structure as well as the proper basicity.

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Preparation of Pd-Ni Bimetallic Catalyst Supported on Polyphenol-Grafted Collagen Fiber and Its Catalytic Behavior in Nitrobenzene Hydrogenation ZHUO Liangming1,2, WU Hao1, LIAO Xuepin1,*, SHI Bi1,* 2010, 31 (12):  1465-1472.  DOI: 10.3724/SP.J.1088.2010.00602 Abstract ( 3244 )   [Full Text(HTML)] () PDF (784KB) ( 1189 )   A novel Pd-Ni bimetallic nanoparticle catalyst supported on epigallocatechin-3-gallate (EGCG) grafted collagen fiber (CF), Pd-Ni/CF-EGCG, has been prepared. EGCG was selected as a bridge molecule to anchor Pd-Ni nanoparticles and control the size and distribution of Pd-Ni nanoparticles. The morphology and physical properties of this catalyst were characterized by thermo-gravimetric analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. It was observed that this catalyst was in an ordered fibrous state, and well-dispersed Pd-Ni nanoparticles with an average diameter of 2.2 nm formed at the outer surface of CF. Hydrogenation of nitrobenzene catalyzed by Pd-Ni/CF-EGCG was investigated. An optimal synergistic action can be achieved when the molar ratio of Ni/Pd was 0.8, and the turnover frequency (TOF) was 237 min-1 at 308 K and 1.0 MPa, which is twice as high as that of Pd/CF-EGCG. Pd-Ni/CF-EGCG still has higher activity after reuse five times.

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Cycloaddition of CO2 and Epoxides Catalyzed by Polymer-Supported Quaternary Phosphonium Salts XIONG Yubing*, CUI Zipeng, WANG Hong, WANG Yujiao, WANG Rongmin 2010, 31 (12):  1473-1477.  DOI: 10.3724/SP.J.1088.2010.00544 Abstract ( 2136 )   [Full Text(HTML)] () PDF (493KB) ( 1160 )   Polymer-supported quaternary phosphonium salts were explored to catalyze the cycloaddition of CO2 and epoxides. The results indicated that this heterogeneous catalyst possessed high activity and selectivity in the cycloaddition reaction. The catalyst was characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The influence of CO2 pressure, reaction temperature, reaction time, and catalyst amount on the cycloaddition reaction was investigated. Excellent yield (97.7%) and high selectivity (> 99%) of cyclic carbonates were achieved under the conditions of p(CO2) = 4.5 MPa, 150 oC, 6 h, and catalyst 0.09 g. The catalyst could be recovered easily and reused several times. A possible reaction mechanism for the cycloaddition of CO2 and epoxide to cyclic carbonate over the polymer-supported quaternary phosphonium salt was discussed.

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Palladium-Catalyzed Suzuki Reaction Using a New N-Carbazolyl Diphosphine PENG Zonghai1, FU Haiyan1, MA Menglin2, CHEN Hua1,*, LI Xianjun1 2010, 31 (12):  1478-1482.  DOI: 10.3724/SP.J.1088.2010.00614 Abstract ( 2131 )   [Full Text(HTML)] () PDF (465KB) ( 1963 )   A new diphospine, 6,6′-dimethoxy-2,2′-bis(di-N-carbazolylphosphino)-1,1′-biphenyl (3), has been synthesized from commercially available 3-bromoanisole in five steps and fully characterized by 1H NMR, 31P NMR, 13C NMR, and high-resolution mass spectrometry. The palladium complex with the new ligand 3 provided excellent yields in Suzuki coupling reaction of aryl bromides and phenylo boric acid, even in the presence of hindered and functional groups.

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Deactivation of Cobalt-Based Catalysts for Fischer-Tropsch Synthesis SHI Lihong1,2,*, LI Xiaofeng3, LI Debao2, SUN Yuhan2 2010, 31 (12):  1483-1488.  DOI: 10.3724/SP.J.1088.2010.00617 Abstract ( 2285 )   [Full Text(HTML)] () PDF (704KB) ( 1034 )   Stability tests of Co/SiO2, Co/Ru/SiO2, and hydrophobically-organically modified Co/Ru/SiO2 (Co/Ru/SiO2-S) for Fischer- Tropsch synthesis were carried out. As the time on stream went on, CO conversion decreased in all the cases. The growth of cobalt crystallite and the formation of cobalt silicates species were the reasons for Co/SiO2 deactivation, while the deactivation of Co/Ru/SiO2 and Co/Ru/SiO2-S was only attributed to the growth of cobalt crystallite. The stability of the catalysts was in order of Co/Ru/SiO2-S > Co/SiO2 > Co/Ru/SiO2. Compared with Co/SiO2, the faster deactivation rate for Co/Ru/SiO2 was ascribed to the agglomeration of smaller metal clusters, which were more unstable than the larger metal clusters and therefore more susceptible to sintering processes. Co/Ru/SiO2-S showed the best stability because of no formation of cobalt silicates species and the slow growth of cobalt crystallite.

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Environmental Factors and Deactivation Mechanism of Au/α-Fe2O3 Catalyst during Storage in Ambient Air WEI Jiying, FAN Guifang, JIANG Feng, ZHANG Zhenzhong, ZHANG Lan 2010, 31 (12):  1489-1495.  DOI: 10.3724/SP.J.1088.2010.00618 Abstract ( 2199 )   [Full Text(HTML)] () PDF (595KB) ( 993 )   Au/α-Fe2O3 catalyst samples were prepared by the deposition-precipitation method. By using CO oxidation as a probe reaction, combined with characterizations such as X-ray diffraction, X-ray photoelectron spectroscopy, N2 adsorption-desorption, Fourier transform infrared spectroscopy, H2 temperature-programmed reduction and CO2 temperature-programmed desorption, the environmental factors, such as irradiation and surface adsorption on the stored catalyst, resulting in the catalyst deactivation, were studied. The active Au species on the catalyst and the deactivation mechanism were investigated. The results show that Au3+ and Auδ+ (0 ≤ δ ≤ 1) species were coexisted on the surface of Au/α-Fe2O3 catalyst treated at 110 oC, and the catalyst activity follows the order Au3+ > Auδ+. When stored in ambient air, UV irradiation can cause the reduction of oxidative Au species and the growth of Au particles. Meanwhile, CO2 and H2O in the atmosphere could be adsorbed on the surface of α-Fe2O3 to form some kinds of carbonates. Thus UV irradiation and surface carbonate adsorption may be the main factors resulting in the deactivation of Au/α-Fe2O3 catalyst during storage in ambient air.

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Configuration and Mechanism of Solid-State Photoelectrocatalytic Device ITO/TiO2/ITO ZHAO Fengwei, LI Jing, SHANG Jing*, WANG Qing 2010, 31 (12):  1496-1500.  DOI: 10.3724/SP.J.1088.2010.00626 Abstract ( 2241 )   [Full Text(HTML)] () PDF (428KB) ( 1158 )   A solid-state TiO2 planar device, ITO/TiO2/ITO, was prepared by immobilizing TiO2 film on indium-tin oxide (ITO) substrate with a certain electrode configuration through a dip-coating method. The surface morphology and film thickness of ITO/TiO2/ITO were characterized by scanning electron microscopy. The effects of configurations of the device and hole scavenger (ethanol) on the photoelectrocatalytic synergetic degradation of rhodamine B (RhB) were investigated over the planar device ITO/TiO2/ITO. The decoloration rate of RhB with the initial concentration of 10 mg/L reached 83% within 60 min. The ITO/TiO2/ITO device with larger photoanode area presented better photoelectrocatalytic properties, and the device with the etching width of 2 mm exhibited the highest photoelectrocatalytic activity. The hydroxyl radicals produced by the water adsorbed on TiO2 surface being oxidized by holes played an important role in liquid-phase photoelectrocatalytic degradation of RhB.

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Hybrid Catalysts for Liquefied Petroleum Gas Synthesis from Syngas MA Xiangang1,2, GE Qingjie1,*, FANG Chuanyan1, MA Junguo1, XU Hengyong1,* 2010, 31 (12):  1501-1506.  DOI: 10.3724/SP.J.1088.2010.00633 Abstract ( 2457 )   [Full Text(HTML)] () PDF (575KB) ( 903 )   Direct synthesis of liquefied petroleum gas (LPG) from syngas over hybrid catalysts consisting of methanol synthesis catalyst and Pd-modified zeolites such as Pd/SAPO-11, Pd/ZSM-5, Pd/β, and Pd/Y was investigated in a fixed-bed reactor. Pore diameter of zeolites had great effect on LPG selectivity. The hybrid catalyst composed of methanol synthesis catalyst and Pd/Y demonstrated a good reactivity and more than 73% selectivity for LPG at 300 oC, 2.1 MPa, and the space velocity of 1 500 h-1. N2 adsorption-desorption, NH3 temperature-programmed desorption and temperature-programmed oxidation were carried out to study the properties of the catalysts before and after reaction. The results indicated that coke deposition was the main reason for the catalyst deactivation.

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Metalloporphyrins Supported on Styrene-Hydroxyethyl Methacrylate Copolymer Microspheres: Preparation and Catalytic Performance for Hydroxylation of Cyclohexane YE Yuanjian, HUANG Jinwang*, CAI Jinhua, WU Wenhai, YU Hancheng, ZHOU Xiantai, JI Hongbing, JI Liangnian 2010, 31 (12):  1507-1512.  DOI: 10.3724/SP.J.1088.2010.00627 Abstract ( 2684 )   [Full Text(HTML)] () PDF (424KB) ( 870 )   A series of styrene-hydroxyethyl methacrylate copolymer (P(St-co-HEMA)) microsphere-immobilized metalloporphyrin (MP) were prepared by the esterification of a hydroxyl in copolymer microsphere surface with a carboxyl chloride in the porphyrin ring, and were characterized by scanning electron microscopy, UV-Vis spectroscopy, Fourier transformation infrared spectroscopy and thermal gravimetric analysis. The catalytic performance of these catalysts for cyclohexane hydroxylation in the metalloporphyrin-O2-ascorbic acid system was measured. The results indicated that the supported metalloporphyrins are more efficient than the non-supported ones and can retain their high turnover numbers after being reused four times. The catalytic activity of the immobilized catalysts follows the order of P(St-co-HEMA)FeP > P(St-co-HEMA)MnP > P(St-co-HEMA)CoP.

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Contents for Volume 31 (2010) 2010, 31 (12):  1514-1537.  Abstract ( 1449 )   [Full Text(HTML)] () PDF (778KB) ( 1019 )

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Author Index for Volume 31 (2010) 2010, 31 (12):  1538-1548.  Abstract ( 1247 )   [Full Text(HTML)] () PDF (306KB) ( 790 )