Chinese Journal of Catalysis ›› 2012, Vol. 33 ›› Issue (6): 1032-1040.DOI: 10.3724/SP.J.1088.2012.11259

• Research papers • Previous Articles     Next Articles

Preparation and Catalytic Performance of Phosphotungstic Acid Active Sites Supported on Periodic Mesoporous Organosilica of SBA-15

LIU Cheng1, TAN Rong1,b, SUN Wenqing1, YIN Donghong1,2,a   

  1. 1Institute of Fine Catalysis and Synthesis, Hunan Normal University, Changsha 410081, Hunan, China; 2Research and Development Center, China Tobacco Hunan Industrial Corporation, Changsha 410014, Hunan, China
  • Received:2011-12-29 Revised:2012-02-19 Online:2012-05-30 Published:2012-05-30

Abstract: A functionalized periodic mesoporous organosilica (PMO), Bis-PImBr-PMO-SBA-15, incorporated with bridging bis-imidazolium ionic liquid moieties was synthesized via a sol-gel procedure. Keggin-type 12-phosphotungstic acid (H3PW12O40? xH2O) was immobilized onto Bis-PImBr-PMO-SBA-15 by the way of anion-exchange, which provided the mesoporous organosilica-supported Keggin-type 12-tungstophosphate catalyst (PW-Bis-PImBr-PMO-SBA-15). X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, Fourier transform infrared spectroscopy, and thermal analysis results showed that both Bis-PImBr-PMO-SBA-15 and PW-Bis-PImBr-PMO-SBA-15 maintained the typical characteristics of the mesoporous material, and the Keggin-structure of the 12-phosphotungstate anion was intact after immobilization. The catalytic performance of PW-Bis-PImBr-PMO-SBA-15 in the selective oxidation of benzyl alcohol by 30% H2O2 was investigated. The PW-Bis-PImBr-PMO-SBA-15 showed higher catalytic activity than bulk HPW or siliceous SBA-15-supported Keggin-type 12-tungstophosphate catalyst (HPW/SBA-15), the conversion of benzyl alcohol and the selectivity to benzaldehyde were as high as 95% and 94%, respectively. The bis-imidazolium cations were thought to mediate the redox behavior of the Keggin PW12 anions, which in turns enhanced the activity and stability of the catalyst.

Key words: Keggin-type 12-phosphotungstate acid, ionic liquid, periodic mesoporous organosilica, SBA-15 zeolite, benzyl alcohol, catalytic oxidation, hydrogen peroxide