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Li X.,Beihang University | Qin G.,Beihang University | Wang Y.,Kailuan Coal Chemical R and nter | Wei W.,Beijing Union University
Journal of Sol-Gel Science and Technology | Year: 2014

Spherical mesoporous silica–alumina aerogel like beads based on sol–gel technology and the drop wise addition have been synthesized and used as catalyst support for phosphotungstic acid (PWA). Their catalytic performances in the isopropylation of naphthalene with isopropanol were investigated in a batch reactor. It was found that PWA was highly dispersed on the silica–alumina support and their Keggin structure can be retained. In addition, PWA/SiO2–Al2O3 catalyst showed high surface area, both of Lewis acid sites and Brönsted acid sites. Because of having more Brönsted acid sites, silica–alumina supported acid catalysts showed much higher conversion (87.97 %) and selectivity to diisopropylnaphthalenes (41.41 %) and β,β-products (59.82 %) than pure acid and reactive supports in the isopropylation of naphthalene. The catalytic behavior has been discussed in relation with the physical chemical properties of catalysts, reaction and activation temperature and reaction time. © 2014, Springer Science+Business Media New York. Source


Li X.,Beihang University | Qin G.,Beihang University | Wang Y.,Kailuan Coal Chemical R and nter | Wei W.,Beijing Union University
Journal of Porous Materials | Year: 2014

Crack-free mesoporous equimolar SiO2–Al2O3–TiO2 ternary aerogel beads have been synthesized and characterized. Silica sol, alumina sol, and titania sol were synthesized individually to prevent the formation of inhomogeneous structure due to the different hydrolization and polymerization rate of individual precursor. After mixing these three types of acidic sols, SiO2–Al2O3–TiO2 ternary beads were prepared by the ball dropping method. The ternary aerogel beads were typically mesoporous, showing high surface area (305 m2 g−1), large pore volume (1.32 cm3 g−1), and high surface acid amount (0.884 mmol NH3 g−1). Moreover, the acid sites of the ternary aerogel beads showed higher thermal stability than those of binary aerogel beads. Gradient drying (GD), supercritical drying (SD), ambient drying (AD), extended aging (EA) and hydrophobic modifying drying (HM) have been employed to investigate the effects of drying method on the characteristics of the aerogel beads. The surface areas of the ternary aerogel beads obtained by different drying methods decrease in the sequence EA > HM > GD > SD > AD. The ternary aerogel beads have been characterized by scanning electron microscopy, nitrogen adsorption, X-ray powder diffraction, Fourier-transform infrared spectroscopy (FTIR), solid-state NMR, temperature-programmed desorption measurements, pyridine adsorption FTIR, and differential scanning calorimetry. © 2014, Springer Science+Business Media New York. Source


Fang C.-X.,Beijing University of Chemical Technology | Fang C.-X.,Kailuan Coal Chemical R and nter | Yu Y.,Kailuan Coal Chemical R and nter | Wang Y.-T.,Kailuan Coal Chemical R and nter | Qu Y.-X.,Beijing University of Chemical Technology
Xiandai Huagong/Modern Chemical Industry | Year: 2012

The research progress of cyclohexene hydration catalysts and process is reviewed in this paper. The characteristics of sulfuric acid, ion exchange resins, zeolites and other types of catalysts, which have been investigated, are analyzed and compared. It is concluded that the ZSM-5 zeolite is the most suitable catalyst and the development of reactive distillation is expected to further improve this process. Source


Fang C.-X.,Beijing University of Chemical Technology | Fang C.-X.,Kailuan Coal Chemical R and nter | Qu Y.-X.,Beijing University of Chemical Technology | Wang Y.-T.,Beijing University of Chemical Technology | And 3 more authors.
Xiandai Huagong/Modern Chemical Industry | Year: 2013

ZSM-5 zeolite catalyst is synthesized by pre-crystallization method, which is characterized by XRD, SEM, N2-adsorption and NH3-TPR methods. The results show that ZSM-5 zeolite has a typical MFI structure with average particles size less than 300 nm. It is distributed as spherical type and has appropriate surface properties and acidity. When the obtained ZSM-5 zeolite is used as catalyst for hydration reaction of cyclohexene, the conversion rate, selectivity and yield are 12.65%, 97.84% and 12.38%, respectively, under the following conditions: 130°C of reaction temperature, 6 MPa of pressure, 2:5 (volume ratio) of cyclohexene to water, 12 wt% of the amount of catalyst, 300 r/min of the stirring speed and 4 h of reaction time. Source

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