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Xu X.,Dalian University of Technology | Li X.,Dalian University of Technology | Li X.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Wang A.,Dalian University of Technology | And 6 more authors.
Helvetica Chimica Acta | Year: 2011

1,2,3,4-Tetrahydro-4,6-dimethyldibenzothiophene was prepared by coupling 2-bromo-3-methylcyclohexanone with 2-methylbenzenethiol and annulating the product with the aid of polyphosphoric acid. A mixture of 1,2,3,4-tetrahydro-4, 6-dimethyldibenzothiophene and 4,6-dimethyldibenzothiophene was prepared by coupling 2-bromo-3-methylcyclohex-2-en-1-one with 2-methylbenzenethiol and annulating the product with the aid of polyphosphoric acid. 2-Bromo-3- methylcyclohexanone was synthesized by conjugate addition of Me3Al to 2-bromocyclohex-2-en-1-one with CuBr as catalyst and 2-bromo-3-methylcyclohex- 2-en-1-one by bromination-elimination of 3-methylcyclohex-2-en-1-one. 1,2,3,4,4a,9b-Hexahydro-4,6-dimethyldibenzothiophene was prepared by reduction of 1,2,3,4-tetrahydro-4,6-dimethyldibenzothiophene with Zn and CF 3COOH. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland. Source


Wu C.,Dalian University of Technology | Li X.,Dalian University of Technology | Li X.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Wang A.,Dalian University of Technology | Wang A.,Liaoning Key Laboratory of Petrochemical Technology and Equipments
Shiyou Xuebao, Shiyou Jiagong/Acta Petrolei Sinica (Petroleum Processing Section) | Year: 2010

TiO2 modified Ni-Mo/MCM-41 hydrodesulfurization (HDS) catalysts were prepared by a consecutive impregnation method, and the effects of TiO2 as well as its introduction order on the HDS performance of Ni-Mo/MCM-41 were studied by using a model fuel of decalin containing 0.8% DBT. The UV-Vis, TPR and NH3-TPD results indicated that both the coordination states, the reducibility as well as the surface acidity of the oxidic precursor of Ni-Mo/MCM-41 were not remarkably affected by the introduction of TiO2. The HDS results showed that the addition of TiO2 suppressed the direct desulfurization pathway (DDS) activity of Ni-Mo/MCM-41, but significantly enhanced its hydrogenation pathway (HYD) activity, leading to an enhanced global HDS activity. The promoting effect was more pronounced when TiO2 was introduced after the impregnation of Ni-Mo over MCM-41. On the base of the product compositions, it is suggested that the improved HYD and HDS activities of TiO2-containg Ni-Mo/MCM-41 catalysts may be attributed to the enhanced acidity of the sulfides. Source


Li J.,Dalian University of Technology | Li X.,Dalian University of Technology | Li X.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Wang A.,Dalian University of Technology | And 2 more authors.
Shiyou Xuebao, Shiyou Jiagong/Acta Petrolei Sinica (Petroleum Processing Section) | Year: 2010

Na2O was introduced to NiMo/MCM-41 catalyst precursor by different sequences, and the hydrodesulfurization (HDS) performances of the prepared catalysts were studied by using a model fuel of decalin solution containing 0.8% DBT. The results indicated that the introduction of Na2O not only facilitated the formation of β-NiMoO4, leading to decreased dispersion of active species, but also suppressed the reducibility of NiMo/MCM-41 precursor. The coordination states of Mo species were affected by Na2O introduced by the consecutive impregnation methods. The HDS activity of NiMo/MCM-41 was strongly affected by the Na2O introduction sequence. For the catalyst in which Na2O was introduced by a co-impregnation method, both the activities of the hydrogenation pathway (HYD) and direct desulfurization pathway (DDS) were suppressed, resulting in a decrease in the overall HDS activity. Compared with the co-impregnation and the introduction of Na2O after NiMo active components, the addition of Na2O before the deposition of these active components showed much less influence on the HYD activity, but significantly enhanced DDS activity of NiMo/MCM-41, thus an improvement in the overall HDS activity was observed. Both the activity and selectivity of the sulfide catalysts can be modified by adapting a proper addition sequence of the alkali-metal oxides, which is an effective way for the modification of HDS catalysts. Source


Li X.,Dalian University of Technology | Li X.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Zhang Y.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Wang A.,Dalian University of Technology | And 4 more authors.
Catalysis Communications | Year: 2010

TiO2- and CeO2-promoted bulk Ni2P catalysts were prepared by impregnation and in-situ H2 temperature-programmed reduction method. The prepared catalysts were characterized by XRD and XPS. The hydrogenation activities of the catalysts were studied using 1.5 wt.% 1-heptene in toluene and 1.0 wt.% phenylacetylene in ethanol as the model feeds. The results indicate that bulk Ni2P possesses low hydrogenation activity but is tunable by simply controlling the content of the additives (TiO2 or CeO2), suggesting that TiO2 and CeO2 are effective promoters to enhance the hydrogenation activity of Ni2P. © 2010 Elsevier B.V. Source


Yang H.,Dalian University of Technology | Li X.,Dalian University of Technology | Li X.,Liaoning Key Laboratory of Petrochemical Technology and Equipments | Wang A.,Dalian University of Technology | And 3 more authors.
Cuihua Xuebao/Chinese Journal of Catalysis | Year: 2014

MoO3/P25 catalysts were prepared by an impregnation method. The catalysts were characterized by X-ray diffraction, ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, and laser Raman spectroscopy, and their photocatalytic activty was evaluated by the degradation of methylene blue dye under visible light. The monolayer dispersion threshold of MoO3 on P25 was around 0.1 g/g. The strong interaction between the monolayer-dispersed tetrahedral-coordinated molybdenum oxide species and P25 led to a decrease in the band gap of P25, thus increasing the visible light absorption of the catalyst. Crystalline MoO3 was formed on catalysts with a MoO3/P25 mass ratio above 0.1. In these cases, the visible light absorption of the catalysts decreased with increasing MoO3 content. The band gap of the catalyst was not the only factor affecting its photocatalytic activity for the degradation of methylene blue under visible light. MoO3/P25 with the MoO3 to P25 mass ratio of 0.25, which possessed not only suitable band gap but also a certain amount of crystalline MoO3, showed the best catalytic performance. © 2014, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved. Source

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