|
|
|
Preparation and characterization of SO42-/TiO2 and S2O82-/TiO2 catalysts |
| MA Xuedan1, GUO Daishi1, JIANG Qizhong1, MA Zifeng1, MA Zhengfei2, YE Weidong3, LI Chunbo3 |
| 1.Department of Chemical Engineering, Shanghai Jiaotong University, Shanghai 200240, China; 2.College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China; 3.Xinchang Pharmaceutical Factory, Zhejiang Pharmaceutics Co. Ltd., Xinchang 312500, China |
|
|
|
|
Abstract Nanosized solid superacids SO42-/TiO2 and S2O82-/TiO2, as well as MCM-41-supported SO42-/ZrO2, were prepared. Their structures, acidities, and catalytic activities were investigated and compared using XRD, N2 adsorption-desorption, and in situ FTIR-pyridine adsorption, as well as an evaluation reaction with pseudoionone cyclization. The results showed that SO42-/TiO2 and S2O82-/TiO2 possess not only nanosized particles with diameters <7.0 nm, a BET surface greater than 140 cm2/g and relatively regular mesostructures with pores around 4.0 nm, but also a pure anatase phase and strong acidity. Different from the Lewis acid nature of SO42-/ZrO2/MCM-41, SO42-/TiO2 and S2O82-/TiO2 exhibit mainly Br¢nsted acidities. The strongest Br¢nsted acid sites were produced on SO42-/TiO2 promoted with H2SO4, while Lewis acid sites on S2O82-/TiO2 even stronger than those on SO42-/ZrO2/MCM-41 were generated when persulfate solution was used as sulfating agent. Because of their distinct acid natures, SO42-/TiO2 and S2O82-/TiO2 exhibited catalytic activities for the cyclization of pseudoionone that were much higher than that of SO42-/ZrO2/MCM-41. It can be concluded that the existence of more Br¢nsted acid sites was favorable for proton participation in the cyclization reaction.
|
|
Issue Date: 05 March 2007
|
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
