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396 results on '"Xu, Hualong"'

157. Synthesis of 2-Arylbenzothiazoles by Copper-Catalyzed One-Pot.

Author

Xu, Hualong, Luo, Chun, Li, Zhengkai, Xiang, Haifeng, and Zhou, Xiangge

Subjects
*THIAZOLE derivatives, *CHEMICAL synthesis, *COPPER catalysts, *BENZYLAMINES, *SULFUR
Abstract

Copper-catalyzed of 2-iodoanilines, benzylamines, and sulfur powder are reported to afford benzothiazoles in a simple by using water as solvent. A variety of 2-arylbenzothiazoles were obtained in moderate to good yields up to 88%. [ABSTRACT FROM AUTHOR]

Published
2016
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193. Sliding Mode Control Based on Fuzzy Neural Network for Missile Electro-hydraulic Servo Mechanism.

Author

Huang, De-Shuang, Li, Kang, Irwin, George William, Yu, Chunlai, Xu, Hualong, Liu, Yunfeng, and Huang, Shiqi

Abstract

The position tracking control of a missile electro-hydraulic servo Mechanism is studied. Since the dynamics of the system are highly nonlinear and have large extent of model uncertainties, such as big changes in parameters and external disturbance, a design method of sliding mode control (SMC) based on fuzzy neural network (FNN) is proposed. A FNN is introduced in conventional SMC, which uses the dynamical back propagation (BP) algorithm to ensure the existing condition of SMC. The chattering brought by sliding mode switch control can be effectively attenuated, without sacrificing the robustness of SMC. Simulation results verify the validity of the proposed approach. [ABSTRACT FROM AUTHOR]

Published
2006
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197. SBA-15 based catalysts in catalytic N2O decomposition in a model tail-gas from nitric acid plants

Author

Xu, Xiaoding, Xu, Hualong, Kapteijn, F., and Moulijn, J.A.

Subjects
*CHEMICAL inhibitors, *NITROGEN oxides, *PLATINUM group catalysts, *GREENHOUSE gases, *OZONE layer
Abstract

Nitrous oxide (N2O) is a greenhouse gas and damages the ozone layer. Nitrous oxide from nitric acid plants is currently the major industrial N2O source. Many catalysts are active for pure N2O decomposition, but few are effective under realistic conditions, due to the relatively low N2O concentration compared to those of inhibitors present in the exhaust gases, i.e. H2O, O2 and NOx. In the present work, Si-SBA-15 and Al-SBA-15 were used to prepare Fe, Ru or Rh catalysts by ion-exchange, impregnation or precipitation method. The effect of steam treatment was also studied. Their activities were evaluated in an automated six-flow reactor system using a model tail-gas under conditions representative for nitric acid plants.The performance depends on the metal species and preparation method. When the carrier, preparation method and metal loading are the same, the activity decreases as follows: Rh > Ru > Fe. Steam-treatment has little influence on catalytic activity unlike for FeZSM-5 catalysts. Impregnated Rh on Al-grafted SBA-15 catalyst shows the best performance per weight of catalyst. However, per mol of active metal (Rh, Ru and Fe) species, catalysts by ion exchange are better than those by impregnation. It is concluded that the improved performance of Rh on Al-grafted SBA-15 is caused by a better dispersion and an enhanced stability due to Al incorporation, but not due to an enhanced acidity thereof. [Copyright &y& Elsevier]

Published
2004
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198. Hydrogenation of methyl benzoate to benzaldehyde over manganese oxide catalysts prepared from Mg/Mn/Al hydrotalcite-like compounds

Author

Chen, Aimin, Xu, Hualong, Yue, Yinghong, Hua, Weiming, Shen, Wei, and Gao, Zi

Subjects
*CHEMICAL inhibitors, *CATALYSTS, *HYDROGENATION, *POTASSIUM
Abstract

Mn–Al and Mg–Mn–Al hydrotalcite-like compounds (HTlcs) were synthesized by a coprecipitation method. The activity of the calcined HTlcs for hydrogenation of methyl benzoate to benzaldehyde was tested. The effects of Mn/Al and Mg/Mn ratio, preparation and reaction conditions, and potassium promoter on the catalytic performance of the catalysts were investigated. The prepared catalysts give better performance than conventional 10% Mn/γ-Al2O3 catalyst. The conversion of methyl benzoate and selectivity to benzaldehyde on 3% K/Mg0.2Mn1.8Al1 catalyst at 390 °C are 90.0 and 88.0%, respectively. XRD, TPR and CO2-TPD studies show that the redox and basic properties of the catalysts play important roles in the reaction. A suitable degree of reduction and a small number of basic sites on the catalyst lead to a high activity and selectivity to benzaldehyde. [Copyright &y& Elsevier]

Published
2004
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199. Highly stable boron-modified hierarchical nanocrystalline ZSM-5 zeolite for the methanol to propylene reactionElectronic supplementary information (ESI) available: synthesis procedure, characterization method, catalyst test, SEM and TEM images, 11B and 27Al MAS NMR spectra, TG curves, catalytic performance on MTP, XRD patterns. See DOI: 10.1039/c4cy00376d

Author

HuThese authors contributed equally to this work., Zhijie, Zhang, Hongbin, Wang, Lei, Zhang, Hongxia, Zhang, Yahong, Xu, Hualong, Shen, Wei, and Tang, Yi

Abstract

A highly stable MTP (methanol to propylene) catalyst, boron-modified hierarchical nanocrystalline ZSM-5 zeolite, has been constructed by a facile salt-aided seed-induced route. The cooperative effect of its hierarchical structure and modified acidity gives rise to a significantly stable activity (725 h) even at a high WHSV (weight hourly space velocity) of 4.0 h−1.

Published
2014
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200. Constructing an oxygen vacancy- and hydroxyl-rich TiO2-supported Pd catalyst with improved Pd dispersion and catalytic stability.

Author

Liu, Huimin, Yuan, Chenyi, Wu, Shipeng, Sun, Chao, Huang, Zhen, Xu, Hualong, and Shen, Wei

Subjects
*METAL catalysts, *DISPERSION (Chemistry), *CATALYSTS, *REACTIVE oxygen species, *WATER gas shift reactions, *PRECIOUS metals
Abstract

Surface property modification of catalyst support is a straightforward approach to optimize the performance of supported noble metal catalysts. In particular, oxygen vacancies and hydroxyl groups play significant roles in promoting noble metal dispersion on catalysts as well as catalytic stability. In this study, we developed a nanoflower-like TiO2-supported Pd catalyst that has a higher concentration of oxygen vacancies and surface hydroxyl groups compared to that of commercial anatase and P25 support. Notably, due to the distinctive structure of the nanoflower-like TiO2, our catalyst exhibited improved dispersion and stabilization of Pd species and the formation of abundant reactive oxygen species, thereby facilitating the activation of CO and O2 molecules. As a result, the catalyst showed remarkable efficiency in catalyzing the low-temperature CO oxidation reaction with a complete CO conversion at 80 °C and stability for over 100 h. [ABSTRACT FROM AUTHOR]

Published
2023
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