Xu Qiao

Efficient cyclohexyl acrylate production by direct addition of acrylic acid and cyclohexene over SBA-15-SO3H

A set of propysulfonic acid modified mesostructured silica materials (SBA-15-SO3H) were prepared by a convenient one-pot co-condensation method. Samples were characterized by XRD, FT-IR, Py-FTIR, N2 adsorption–desorption, elemental analysis and acid–base titration. The catalysts exhibited excellent activities and selectivities for addition esterification of acrylic acid and cyclohexene. The highest catalytic activity (82.8xa0%) and selectivity (92.6xa0%) were obtained over SBA-15-SO3H (15xa0%). The efficient catalytic performance of SBA-15-SO3H (15xa0%) was attributed to the high surface area, proper mesopore texture and presence of sulfonic acid groups in its structure. SBA-15-SO3H catalyst was easily separated and recycled with high stability.

Structure and properties of amorphous CeO2@TiO2 catalyst and its performance in the selective catalytic reduction of NO with NH3

Abstract Amorphous CeO 2 @TiO 2 catalyst was prepared by spontaneous deposition method and characterized by XRD, Raman spectra, TEM, N 2 physisorption, H 2 -TPR, NH 3 -TPD and FT-IR; its performance in the selective catalytic reduction (SCR) of NO with NH 3 was investigated. The results show that there is a strong interaction between Ce and Ti which are combined at atomic level. In comparison with the crystal CeO 2 /TiO 2 catalyst prepared by impregnation, the amorphous CeO 2 @TiO 2 catalyst exhibits larger surface area and pore volume, excellent redox ability and acidity, and outstanding catalytic performance in SCR. Over the CeO 2 @TiO 2 catalyst, the conversion of NO reaches 80% at 175°C and retains 96.0%–99.4% at 200–400°C. Moreover, the amorphous CeO 2 @TiO 2 catalyst also shows strong resistance to H 2 O and SO 2 poisoning.

Efficient hydrochlorination of glycerol to dichlorohydrin over the COOH-functionalized mesoporous carbon–silica composites

AbstractnA novel strategy of carbonization and subsequent carboxylation in the confined mesopores of SBA-15 was implemented to synthesize meso-structured carbon/silica(C/Si) composites with enhanced acidity. The XRD and N2 sorption measurements suggested the preservation of ordered mesoporous structure; FTIR characterization indicated that the C/Sis were successfully modified with –COOH and the acidity of COOH–C/Si material was significantly enhanced. COOH–30C/Si(A) with high COOH density of 2.61xa0mmol/g and retained mesoporous structure exhibited superior activity for dichlorohydrin production. Through the optimization of reaction variables, as high as 65.7xa0%, the yield of DCH, can be achieved over COOH–30C/Si(A) after 12xa0h reaction under 130xa0°C. Meanwhile, it was 100xa0% that the conversion of the glycerol can be reached. A significant issue, good durability, especially for practical application, was verified through five consecutive cycles with the optimal reaction variables.n

Iron-doped mesoporous silica, Fe-MCM-41, as an active Lewis acid catalyst for acidolysis of benzyl chloride with fatty acid

Iron-doped mesoporous silica, Fe-MCM-41, with different concentrations of Lewis acidity have been prepared by the hydrothermal method. Physicochemical properties of all Fe-MCM-41 samples were obtained via HRTEM, PXRD and N2 sorption characterization. The surface acidities were tested by NH3-TPD. The catalytic activity of all Fe-MCM-41 materials were evaluated in the acidolysis reaction of benzyl chloride with various fatty acids. The corresponding benzaldehyde and acyl chloride product were synthesized in good conversion and high atom efficiency over the catalyst with the highest Fe content.

Synthesis of tert-butyl acetate via eco-friendly additive reaction over mesoprous silica catalysts with balanced Brönsted and Lewis acid sites

AbstractnThe dual-modified SBA-15 materials (A–S–Si) with Al ions inserting in the framework and −SO3H groups grafting on the pore wall were prepared via a co-condensation method and characterized by a series of techniques. The characterization results implied that the A–S–Si samples have typically mesoporous structure and different acid properties. The catalytic performance of A–S–Si catalysts in the additive reaction of acetic acid with isobutene was studied. The results showed that the conversion of acetic acid strongly depended on the Brönsted acidity, while the selectivity of tert-butyl acetate (TBAC) was linear correlated with the ratio of Brönsted and Lewis acid amounts. The conversion of acetic acid could reach 72xa0% with the selectivity of TBAC as high as 97xa0% over A5–S10–Si with balanced Brönsted and Lewis acid under the optimal conditions. An additional advantage was that the dual-modified catalyst can be recycled and regenerate with good stability.