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Chinese Journal of Catalysis
2011, Vol. 32, No. 11
Online: 14 November 2011


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Prof. Phan and co-workers in their article on pages 1667–1676 report a palladium catalyst immobilized on superparamagnetic CoFe₂O₄ nanoparticles that does not need added phosphine ligands for Suzuki cross-coupling of aryl bromides with phenylboronic acid. The catalyst can be easily recovered by magnetic decantation and can be reused many times. These particles offer advantages over conventional catalyst supports because they can be easily functionalized by silane chemistry, and the magnetic recovery of the catalyst offers a green process for organic transformations.

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Table of Contents for Vol.32 No. 11 2011, 32 (11):  0.  Abstract ( 1424 )   PDF (1114KB) ( 796 )

Research Briefing

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Ligninolytic Peroxidase-Like Activity of a Synthetic Metalloporphine Immobilized onto Mercapto-Grafted Crosslinked PVA Inspired by the Active Site of Cytochrome P450 Paolo ZUCCA, Antonio RESCIGNO, Enrico SANJUST 2011, 32 (11):  1663-1666.  DOI: 10.1016/S1872-2067(10)60277-X Abstract ( 2268 )   [Full Text(HTML)] () PDF (125KB) ( 785 )   A synthetic metalloporphine was immobilized onto a PVA-based and mercapto-grafted solid support, emulating the active site of cytochrome P450. Its ligninolytic peroxidase-like catalytic activity was studied. The coordinated mercapto ligand significantly affected the catalytic features of the catalyst because the oxidation of lignin-model compounds was very slow by comparison with imidazole- and pyridine-coordinated immobilized metalloporphines. Conversely, the catalyst efficiently bleached several industrial dyes and thus demonstrated promising activity for this application. Based on this altered substrate specificity the oxygen-donor catalytic route seems to be more favorable than a single electron oxidation pathway.

Research papers

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Suzuki Reaction of Aryl Bromides Using a Phosphine-Free Magnetic Nanoparticle-Supported Palladium Catalyst Nghia T. BUI, Trung B. DANG, Ha V. LE, Nam T. S. PHAN 2011, 32 (11):  1667-1676.  DOI: 10.1016/S1872-2067(10)60270-7 Abstract ( 3275 )   [Full Text(HTML)] () PDF (622KB) ( 1556 )   A palladium catalyst immobilized on superparaganetic nanoparticles was prepared with a palladium loading of 0.30 mmol/g. The catalyst was characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen adsorption. The immobilized palladium catalyst was an efficient catalyst without added phosphine ligands for the Suzuki cross-coupling reaction of several aryl bromides with phenylboronic acid. The recovery of catalyst was simply by magnetic decantation in the presence of a magnet. The immobilized palladium catalyst can be reused many times without significant degradation in catalytic activity. No leaching of active palladium species into the reaction solution was detected.

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Asymmetric Hydrogenation of Ethyl Pyruvate on Chirally Modified Pt Catalysts Supported on Al2O3@FDU-14 Mesoporous Composites WANG Hai-Hong, WANG Hong-Na, LI Xiao-Hong, WANG Yi-Meng, WU Peng 2011, 32 (11):  1677-1684.  DOI: 10.1016/S1872-2067(10)60274-4 Abstract ( 2403 )   [Full Text(HTML)] () PDF (691KB) ( 959 )   A series of Al2O3@FDU-14 composites with different alumina loadings were prepared using a solid state grinding method. The 4% Pt catalysts supported on Al2O3@FDU-14 were prepared by impregnation using H2PtCl6. X-ray diffraction, transmission electron microscopy, and nitrogen adsorption characterization of the Pt/Al2O3@FDU-14 catalysts indicated that the mesoporous features of the FDU-14 mesopolymer were retained. The Pt/Al2O3@FDU-14 catalysts were used in the asymmetric hydrogenation of ethyl pyruvate after they were chirally modified with cinchonidine. For Al2O3 loading from 5% to 15%, Al2O3 was uniformly dispersed inside the mesoporous channels of FDU-14 host. Ethyl pyruvate conversion and their ee values increased with increasing alumina loading, with a highest ee value of 80%. It was suggested that the alumina coating inside the mesoporous channels of FDU-14 decreased the surface electronic density of the FDU-14 mesopolymer so that cinchonidine can be easily adsorbed on the surface of Pt/Al2O3@FDU-14 catalysts. As compared with chirally modified Pt/FDU-14 catalysts, chirally modified Pt/Al2O3@FDU-14 catalysts gave higher ee values.

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Sensitive Voltammetric Determination of Captopril Using a Carbon Paste Electrode Modified with Nano-TiO2/Ferrocene Carboxylic Acid Jahan Bakhsh RAOOF, Reza OJANI, Mehdi BAGHAYERI 2011, 32 (11):  1685-1692.  DOI: 10.1016/S1872-2067(10)60268-9 Abstract ( 2999 )   [Full Text(HTML)] () PDF (635KB) ( 1446 )   A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO2 nanoparticles was constructed by incorporating TiO2 nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The electrochemical behavior of captopril (CAP) at the surface of the modified electrode was investigated using electroanalytical methods. The modified electrode showed excellent electrocatalytic activity for the oxidation of CAP in aqueous solutions at physiological pH values. Cyclic voltammetric curves showed that the oxidation of CAP at the surface of the modified electrode reduced its overpotential by more than 290 mV. The modified electrode was used for detecting captopril using cyclic voltammetry and square wave voltammetry techniques. A calibration curve in the range of 0.03 to 2400 µmol/L was obtained that had a detection limit of 0.0096 µmol/L (3s) under the optimized conditions. The modified electrode was successfully used for the determination of captopril in pharmaceutical and biological samples.

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Selective Oxidation of Benzyl Alcohol Catalyzed by Palladium Nanoparticles Supported on Carbon-Coated Iron Nanocrystals ZHANG Hai, LIU Ying, ZHANG Xun-Gao 2011, 32 (11):  1693-1701.  DOI: 10.1016/S1872-2067(10)60273-2 Abstract ( 3074 )   [Full Text(HTML)] () PDF (638KB) ( 963 )   A magnetic separable Pd nanoparticles supported on carbon-coated iron nanocrystals (Pd/Fe@C) catalyst was prepared by an impregnation method and characterized by X-ray fluorescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The size of the Pd nanoparticles ranged from 4 nm to 10 nm and the average size was about 7 nm. The principal component of the Pd nanoparticles was determined to be Pd0 with Pd 3d5/2 binding energy at 335.6 eV. The as-made catalyst was applied to the selective oxidation of benzyl alcohol. The effects on the oxidation of benzyl alcohol were investigated in detail, including the amount of catalyst, the solvent, the temperature, and the catalytic activity of recycling. The results indicated that benzaldehyde could be selectively synthesized from benzyl alcohol upon catalysis by Pd/Fe@C. The conversion of benzyl alcohol was 96% and the selectivity for benzaldehyde was 95% when using 0.5% Pd/Fe@C catalyst with acetonitrile as a solvent under an oxygen atmosphere at 80 °C. The catalyst can be easily separated magnetically and high catalytic activity was retained after recycling the catalyst four times.

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Synthesis of Zeolite ZSM-5 Small Particle Aggregates by a Two-Step Method in the Absence of an Organic Template HUANG Xian-Liang, WANG Zheng-Bao 2011, 32 (11):  1702-1711.  DOI: 10.1016/S1872-2067(10)60275-6 Abstract ( 3009 )   [Full Text(HTML)] () PDF (854KB) ( 1182 )   The preparation of zeolite ZSM-5 without using a template was extensively investigated. Zeolite ZSM-5 small particle aggregates were synthesized in the absence of a template using sodium silicate as the silica source and by controlling the nucleation time at high temperature with a simple two-step method in a rotating autoclave on a spit within an oven. The first stage at higher temperature consisted of accelerating the nucleation and the second stage at lower temperature consisted of obtaining small crystals in the absence of a template. The resulting zeolites were characterized by X-ray powder diffraction, scanning electron microscopy, ammonia temperature-programmed desorption, and N2 adsorption. Compared with the micron-sized zeolite crystals that are synthesized in the one-step method, zeolite ZSM-5 small particles prepared by the two-step method have a higher specific surface area and an equivalent acid site content. The sample synthesized by the two-step method mainly contains Brönsted acid sites and a few Lewis acid sites indicating that Al is incorporated into the framework of the zeolite.

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An Efficient and Recyclable Mesostructured Polymer-Supported N-Heterocyclic Carbene-Palladium Catalyst for Sonogashira Reactions YU Tao, LI Ying, YAO Cheng-Fu, WU Hai-Hong, LIU Yue-Ming, WU Peng- 2011, 32 (11):  1712-1718.  DOI: 10.1016/S1872-2067(10)60284-7 Abstract ( 2823 )   [Full Text(HTML)] () PDF (409KB) ( 867 )   Palladium catalyst systems are the most widely used for the formation of C–C and C–N bonds. Environmentally friendly heterogeneous palladium catalysts have strongly stimulated growth in this research area. Herein, a FDU (Fudan University)-15 mesopolymer with p6mm mesostructures that combine the advantages of organic polymers and mesoporous materials was investigated as a new solid support for Pd complexes. The FDU-15 mesopolymer-supported N-heterocyclic carbine (NHC) precursor was developed by a simple chemical functionalization approach. It has been used as a phosphine-free ligand to prepare the novel heterogeneous palladium catalyst FDU-NHC/Pd(II), which efficiently catalyzes Sonogashira reactions between aryl halides and terminal alkynes to afford the corresponding products in good yields. Various techniques such as X-ray diffraction, N2 adsorption-desorption isotherms, high resolution transmission electron microscopy, and X-ray photoelectron spectroscopy have been used to characterize the catalyst. The results indicate that the mesoporous structure of FDU-15 was not affected by immobilization, however, the pore diameter, pore volume, and BET surface area decrease. The stability of the heterogeneous catalyst was also studied. The FDU-NHC/Pd(II) complex catalyst was easily separated from the reaction system by a simple filtration of the reaction mixture and it has been shown to be robust without a significant loss of catalytic activity after recycling and reuse in 10 times.

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The Role of Vanadia for the Selective Oxidation of Benzyl Alcohol over Heteropolymolybdate Supported Alumina Catalysts Pasupulet Siva Nageswara RAO, Kasanneni Tirumala Venkateswara RAO, Potharaju S. SAI PRASAD, Nakka LINGAIAH 2011, 32 (11):  1719-1726.  DOI: 10.1016/S1872-2067(10)60279-3 Abstract ( 2595 )   [Full Text(HTML)] () PDF (985KB) ( 929 )   A series of 12-molybdophosphoric acid (MPA) supported on V2O5 dispersed γ-Al2O3 catalysts with different vanadia loadings were prepared by impregnation and characterized by N2 adsorption-desorption, X-ray diffraction, temperature-programmed reduction, in situ laser Raman spectroscopy, UV-Vis diffused reflectance spectroscopy, scanning electron microscopy, and temperature-programmed desorption of NH3 techniques. Their catalytic activities were evaluated for the vapor phase aerobic oxidation of benzyl alcohol. The catalysts exhibited high catalytic activity and the conversion of benzyl alcohol depended on the vanadia content while the catalyst with 15 wt% V2O5 content showed optimum activity. The characterization results suggest the presence of well-dispersed V2O5 and partially disintegrated Keggin ions of MPA on the support. In situ Raman studies showed a reduced Mo(IV) species when the catalysts were calcined at high temperatures. The high oxidation activity of the catalysts is related to the synergistic effect between MPA and V2O5.

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Preparation of Ru-[bmim]BF4 and Its Catalytic Performance for Selective Hydrogenation of Benzene QIN Yan-Fei, XUE Wei, LI Fang, WANG Yan-Ji, WEI Jun-Fang 2011, 32 (11):  1727-1732.  DOI: 10.3724/SP.J.1088.2011.10643 Abstract ( 2206 )   [Full Text(HTML)] () PDF (488KB) ( 886 )   Ru-[bmim]BF4 catalyst was prepared in the mixed solvent of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and H2O by chemical reduction and was characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results showed that Ru nanoparticles of about 2 nm were highly dispersed in the ionic liquid, and a Ru-carbene complex was obtained between imidazolium cations of [bmim]BF4 and some of Ru particles. The catalytic performance of the catalyst for benzene selective hydrogenation was evaluated. The catalyst showed poor activity but high cyclohexene selectivity in the presence of the Ru-carbene complex. Cyclohexene selectivity was up to 40.5% at 12.2% benzene conversion. When the catalyst was reused, its catalytic activity increased but the selectivity declined. This was due to the transformation from Ru-carbene complex to Ru0 during the reaction process. In addition, the catalytic performance of Ru-[bmim]BF4 remained stable when it was reused further.

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Enzymatic Synthesis of 5'-Palmitate of 5-Fluorouridine Hou-Xue-Dan, ZHANG Yi, LIU Huan, LI Ning, ZONG Min-Hua 2011, 32 (11):  1733-1738.  DOI: 10.3724/SP.J.1088.2011.10739 Abstract ( 2149 )   [Full Text(HTML)] () PDF (753KB) ( 794 )   In a 10 ml co-solvent system of acetone-THF (85/15, volume ratio), the effects of key parameters on the synthesis of 5'-palmitate of 5-fluorouridine (5-FUR) catalyzed by Lipozyme TL IM were investigated. It was revealed that water in the mixture could be removed efficiently by adding molecular sieves, thus significantly improving the yield of the desirable product. The batch enzymatic reaction was successfully scaled up to 200 ml (1 g 5-FUR scale), furnishing a yield of 99%. Moreover, Lipozyme TL IM displayed excellent operational stability in this reaction system. The yield of 97% was obtained after reuse for 10 cycles. Additionally, the volumetric productivity in a packed bed reactor for the synthesis of 5'-O-palmitoyl-5-FUR was 22.4 g/(L·h), which was much higher than that in the batch reactor (0.5 g/(L·h)).

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Ca-Modified Pd/CeO2-ZrO2-Al2O3 Catalysts for Methanol Decomposition LI Xue, WANG Xiao-Wen, ZHAO Ming, LIU Jian-Ying, GONG Mao-Chu, CHEN Yao-Qiang 2011, 32 (11):  1739-1746.  DOI: 10.3724/SP.J.1088.2011.10703 Abstract ( 2229 )   [Full Text(HTML)] () PDF (846KB) ( 870 )   CeO2-ZrO2-Al2O3 and CeO2-ZrO2-Al2O3-CaO supports were prepared by the coprecipitation method and were loaded with Pd by impregnation to form Pd/CeO2-ZrO2-Al2O3 (Pd/CZA) and Pd/CeO2-ZrO2-Al2O3-CaO (Pd/CZACa) catalysts. The catalysts were characterized by X-ray diffraction, low temperature N2 adsorption-desorption, oxygen storage capacity, CO chemisorption, NH3 temperature-programmed desorption (NH3-TPD), CO2 temperature-programmed desorption (CO2-TPD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The catalyst activity for methanol decomposition showed that the Ca modification improved the low-temperature activity of the catalyst, which lowered the complete conversion temperature on 34 oC. NH3-TPD and CO2-TPD showed that the addition of Ca poisoned the acid sites of the support or increased the number of weak basic sites and therefore changed the adsorption-desorption equilibria of the adsorbed species. It also enhanced the metal-support interaction and increased the electronic surroundings of Pd sites, which maintained Pd in a partly oxidized (Pdδ+) state and consequently increased the activity for methanol decomposition according to H2-TPR and XPS measurements.

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Effects of Support Acidity on the Catalytic Performance of Mo/HZSM-5-Al2O3 Catalysts in Olefin Metathesis ZHANG Da-Zhou, LI Xiu-Jie, LIU Sheng-Lin, ZHU Xiang-Xue, XIN Wen-Jie, XIE Su-Juan, ZENG Peng, XU Long-Ya- 2011, 32 (11):  1747-1754.  DOI: 10.3724/SP.J.1088.2011.10744 Abstract ( 2352 )   [Full Text(HTML)] () PDF (872KB) ( 997 )   Mo/HZSM-5-Al2O3 catalyst samples, where the HZSM-5 had different Si/Al ratios (12, 42, and 213), were prepared and evaluated in a fixed-bed reactor. Effects of support acidity changes on the catalytic performance of Mo/HZSM-5-Al2O3 in the metathesis of ethene and 2-butene to propene were investigated. NH3 temperature-programmed desorption and pyridine infrared spectra revealed that the differences in support acidity led to the different anchoring modes of Mo species on the composite supports. Quick deactivation phenomena were observed on Mo/HZSM-5-Al2O3 (Si/Al = 12) due to the high acidity density of the catalyst. For Mo/HZSM-5-Al2O3 (Si/Al = 213), more Mo species dispersed on the alumina in octahedral form and those locating in the zeolite channels existed in the state of (Mo2O5)2+ clusters evidenced by ultraviolet-visible diffuse reflectance spectroscopy and H2 temperature-programmed reduction results. Such distribution was linked with the low metathesis activity and the appearance of the induction period on Mo/HZSM-5-Al2O3 (Si/Al = 213). Mo/HZSM-5-Al2O3 (Si/Al = 42) sample demonstrated the best catalytic activity and reaction stability among the three samples. This was attributed to its suitable acidity amount and optimal distribution of Mo species on the support.

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Preparation of Cellulose-Derived Solid Acid Catalyst and Its Use for Production of Biodiesel from Waste Oils with High Acid Value LOU Wen-Yong, CAI Jun, DUAN Zhang-Qun, ZONG Min-Hua 2011, 32 (11):  1755-1761.  DOI: 10.3724/SP.J.1088.2011.10711 Abstract ( 3418 )   [Full Text(HTML)] () PDF (821KB) ( 1069 )   A cheap cellulose-derived solid acid catalyst (Cellulose-SO3H), containing SO3H groups (1.69 mmol/g), was successfully prepared through sulfonation of incompletely carbonized cellulose. Various preparation variables exerted remarkable effects on the catalytic activity of the prepared catalyst, and the optimal preparation conditions were found as follows: carbonization at 400 oC for 15 h and subsequent sulfonation at 150 oC for 15 h. The resulting catalyst showed significantly higher activity for esterification of oleic acid with methanol than several typical solid acid catalysts (niobic acid, amberlyst-15, and sulfated zirconia). The Cellulose-SO3H catalyst was capable of efficiently catalyzing esterification of other higher fatty acids (palmitic acid and stearic acid) with methanol to the corresponding fatty acid methyl esters (biodiesel). Moreover, the conversion of waste oils containing 27.8% free fatty acids to biodiesel catalyzed by Cellulose-SO3H was investigated. It was found that the optimal molar ratio of methanol to oil, catalyst amount, reaction temperature, and reaction time were 25, 10% (based on the mass of waste oil), 85 °C, and 10 h, respectively. Under the optimal reaction conditions, the yield of biodiesel obtained catalyzed by Cellulose-SO3H was much higher than that by the above-mentioned three typical catalysts. Cellulose-SO3H still retained above 90% of its original catalytic activity even after 30 cycles of successive re-use, indicating excellent operational stability. It can be clearly seen that the Cellulose-SO3H catalyst displays tremendous potential for biodiesel production.

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Synthesis and Properties of Mesoporous TiO2 Using Nano-cellulose Template Prepared by Alkali Method CHEN Xiao-Yun, CHEN Xing, HONG Shi-Wei, CHEN Xiao, HUANG Biao 2011, 32 (11):  1762-1767.  DOI: 10.3724/SP.J.1088.2011.10755 Abstract ( 3113 )   [Full Text(HTML)] () PDF (768KB) ( 3132 )   Mesoporous TiO2 was synthesized by a hydrolysis-precipitation method using biological renewable resources of nano-cellulose as template and using TiCl4 as precursor. The photocatalytic activity of TiO2 was investigated by the degradation of phenol under ultraviolet light irradiation. Transmission electron microscopy, X-ray diffraction, thermogravimetry-differential thermal analysis, and N2 adsorption-desorption were used for catalyst characterization. The results showed that TiO2 synthesized with alkali nano-cellulose template exhibited high activity under UV irradiation. The material had average size of about 13.5 nm in diameter and exhibited mesoporous structure with specific area of 176 m2/g and average pore size of 6.17 nm. The addition of alkali nano-cellulose template can retard phase transformation. The higher photocatalytic activity was attributed to the small grain size, more pores, and higher specific surface area of the catalyst.

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Selective Hydrogenation of Maleic Anhydride to γ-Butyrolactone over TiOx (x < 2) Surface-Modified Ni/TiO2-SiO2 in Liquid Phase YANG Yan-Ping, ZHANG Yin, GAO Chun-Guang, ZHAO Yong-Xiang 2011, 32 (11):  1768-1774.  DOI: 10.3724/SP.J.1088.2011.10709 Abstract ( 2425 )   [Full Text(HTML)] () PDF (864KB) ( 954 )   TiO2-SiO2 aerogel with different TiO2 content was prepared by the sol-gel method. Ni/TiO2-SiO2 catalyst samples were then prepared via impregnation, and were applied to the selective hydrogenation of maleic anhydride (MA) to γ-butyrolactone (GBL). The catalyst samples were characterized by infrared spectroscopy, N2 adsorption-desorption, temperature-programmed reduction, X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, and H2 temperature-programmed adsorption-mass spectroscopy techniques. The characterization results indicated that smaller Ni0 species favored the formation of GBL. Meanwhile, TiOx (x < 2) species, produced by the partial reduction of TiO2, was generated during the reduction process. The formation of TiOx (x < 2) species effectively promoted the hydrogenation of C=O group. Therefore, the hydrogenation of carbonyl was affected by both the size of Ni0 and TiOx species. When the synergistic effect of small Ni0 and TiOx species existed, the catalyst showed higher hydrogenation activity for C=O group.