能源化学(英文版)

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Advances in the Partial Oxidation of Methane to Synthesis Gas

Quanli Zhu;Xutao Zhao;Youquan Deng

2004, 13 (4): 191-203.

摘要 ( 8807 )

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The conversion and utilization of natural gas is of significant meaning to the national economy, even to the everyday life of people. However, it has not become a popular industrial process as expected due to the technical obstacles. In the past decades, much investigation into the conversion of methane, predominant component of natural gas, has been carried out. Among the possible routes of methane conversion, the partial oxidation of methane to synthesis gas is considered as an effective and economically feasible one. In this article, a brief review of recent studies on the mechanism of the partial oxidation of methane to synthesis gas together with catalyst development is wherein presented.

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Catalytic Combustion of Methane over Ti-Pillared Clay Supported Copper Catalysts

Xiufeng Xu;Yanfei Pan;Xiaoyan Cui;Zhanghuai Suo

2004, 13 (4): 204-208.

摘要 ( 12009 )

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A natural montmorillonite, produced from Laiyang of Shandong Province, was pillared by Tipolycations to form Ti-pillared clay (Ti-PILC), and characterized by BET surface area, infrared spectra and thermal analysis. The characterization results show that Ti-PILC has a larger surface area and more hydroxyl groups than that of the natural clay, thus was used as the catalytic carriers to prepare supported Cu catalysts (Cu/Ti-PILC). The 20%Cu/Ti-PILC with 10mmol/g of Ti/clay shows a high catalytic performance of methane combustion in the temperature range of 400-500℃.

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Study of Dibenzothiophene Adsorption Over Carbon Nanotube Supported CoMo HDS Catalysts

Haiyang Chen;Xichen Zhou;Hongyan Shang;Chenguang Liu;Jieshan Qiu;Fei Wei

2004, 13 (4): 209-217.

摘要 ( 9368 )

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Adsorption properties of dibenzothiophene (DBT) on a CNT (carbon nanotube) support as well as on CoMoS/CNT and CoMoO/CNT catalysts have been studied. Consecutive desorption of adsorbates was measured by TGA. The commonly used carriers AC (activated carbon), γ-Al2O3, and their supported catalysts (CoMoO/AC, CoMoS/AC, CoMoO/γ-Al2O3, CoMoS/γ-Al2O3) were also subjected to analysis for comparison. The acidic properties of the samples were characterized using the NH3-TPD technique. Correlation between the adsorption of DBT and the acidic properties of the catalysts has been established. It was found that the Co-Mo catalysts in the sulfide state adsorbed much more DBT molecules than the corresponding Co-Mo catalysts in the oxide state. The CoMoS/CNT catalyst exhibited very high HDS activity and selectivity, as compared with the CoMoS/γ-Al2O3 catalysts. Based on the BET data of the high hydrogenolysis/hydrogenation selectivity of the CoMoS/CNT, it was deduced that more than 90% of the DBT molecules adsorbed on the CoMoS/CNT with an end-on mode, and the surface of the CoMoS/CNT catalyst was almost fully covered with DBT molecules. Although the AC support had very high surface area and high loading ability, the AC supported CoMoS catalyst showed lower HDS activity, as compared with the CoMoS/γ-Al2O3 catalyst.

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Ethylene Polymerization Catalyzed by Monocyclopentadienyl Titanium Complex Containing 8-Quinolinolato

Jianjun Yi;Xiaoguang Zhao;Han Zhou;Zhenhua Jing

2004, 13 (4): 218-224.

摘要 ( 8077 )

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A monocyclopentadienyl titanium complex containing 8-quinolinolato (QCpTiCl2) was synthesized. Its activities in ethylene polymerization at various Al/Ti molar ratios, different temperatures and activation time were investigated. The activity with a Al/Ti molar ratio of 500 exhibited a maximum of 2.8×105 g/(mol·h) at 30℃ . The activation time of QCpTiCl2 with MAO before polymerization also plays a role on the activity. The structural properties of the produced polyethylene (molecular weight, molecular weight distribution and melting point) were discussed. Kinetic behaviors of ethylene polymerization with the QCpTiCl2/MAO system at different Al/Ti molar ratios were studied. For the QCpTiMeCl/MAO system and the CpTiMe2Cl/MAO system, binding energies of the examined intermediates were calculated by quantum-mechanical method based on ADF program, respectively. It is confirmed that the chlorinebridged adduct formed by the reaction of QCpTiMeCl with MAO is thermodynamically steady. In the case of the QCpTiMeCl/MAO system, olefin-separated ion pair (OSIP) mechanism is much favorable than ion-pair dissociation (IPD) mechanism. The evidence that the CpTiMe2Cl/MAO system is unfavorable to form active species with ethylene supports the experimental result that the CpTiMe2Cl/MAO system showed lower activity for ethylene polymerization than the QCpTiMeCl/MAO system.

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Kinetics of Methanol Carbonylation to Methyl Formate Catalyzed by Sodium Methoxide

Liang Chen;Jianghong Zhang;Ping Ning;Yunhua Chen;Wenbing Wu

2004, 13 (4): 225-230.

摘要 ( 11087 )

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Kinetics of synthesis of methyl formate from carbon monoxide and methanol, using sodium methoxide as the catalyst and pyridine as the promoter in a batch reactor, was studied. Kinetic parameters such as the apparent reaction orders, the rate constant and the apparent activation energies were obtained. The experimental results showed that both the reaction orders with respect to CO and methanol equal to 1, the general reaction kinetic equation is (-r)=-dp(CO)/dt=k·p(CO)·[MeOH], and the rate constant is k=8.82·106exp [-61.19·103/(R ·T)] in the presence of pyridine. The apparent activation energies had decreased 6.44 kJ/mol and the rate constant had increased more than 1.5 times when pyridine was used as the promoter in the catalyst system.

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Synthesis and Characterization of Magnesium Substituted Aluminophosphate Molecular Sieves with AEL Structure

Benjing Xu;Ling Qian;Xinmei Liu;Chunmin Song;Zifeng Yan

2004, 13 (4): 231-237.

摘要 ( 7452 )

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MAPO-11 molecular sieves were synthesized by hydrothermal methods. The in uence of precursor of magnesium, Mg/Al ratio, synthesis temperature, synthesis time and the type of template on the formation and properties of MAPO-11 molecular sieves was examined. The samples were characterized by the techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric/ differential thermogravimetric analysis (TG-DGA), etc. The results show that the shape and size of crystal were influenced by the precursor of Mg, the Mg/Al ratio and the type of template, and the TG-DGA analysis shows that MAPO-11 molecular sieves as-synthesized have poor thermal stability.

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Gas Phase Selective Catalytic Oxidation of Toluene to Benzaldehyde on V2O5-Ag2O/Al2O3 Catalyst

Tonglai Zhang;Liqiu Mao;Weihua Liu

2004, 13 (4): 238-243.

摘要 ( 8940 )

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Gas phase selective catalytic oxidation of toluene to benzaldehyde was studied on V2O5- Ag2O/γ-Al2O3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM, and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V+Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No. 4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzaldehyde were higher than those on the undoped catalyst. This was attributed to the disordered structure of V2O5 lattice of the K-doped catalyst and a better interfacial contact between the particles.

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Methane Decomposition and C2 Hydrocarbon Formation

Jianxun He;Miao Hu;Zhiguo Lu

2004, 13 (4): 244-247.

摘要 ( 8310 )

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The infrared emission spectra of methane, H·, CH and C2 hydrocarbons in natural gas were measured. The processes of methane decomposition and formation of C2 hydrocarbons were studied. The experiment shows that methane decomposition can be divided into three periods as the reaction proceeds. In the first period, a large number of free radicals were formed. While in the last period, the formation of C2 hydrocarbons and the decrease of free radicals were observed. The time and conditions of methane decomposition and formation of C2 hydrocarbons are different.

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