催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (6): 1032-1040.DOI: 10.3724/SP.J.1088.2012.11259

• 研究论文 • 上一篇    下一篇

离子液体功能化有序介孔 SBA-15 孔壁定域化磷钨酸催化活性中心构建及其催化性能研究

刘成1, 谭蓉1,b, 孙文庆1, 银董红1,2,a   

  1. 1湖南师范大学精细催化合成研究所, 湖南长沙 410081; 2湖南中烟工业有限责任公司技术研发中心, 湖南长沙 410014
  • 收稿日期:2011-12-29 修回日期:2012-02-19 出版日期:2012-05-30 发布日期:2012-05-30

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

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摘要： 采用溶胶-凝胶法合成了一种桥键嵌入型双咪唑离子液体功能化介孔硅基材料 (Bis-PImBr-PMO-SBA-15), 然后离子交换将 Keggin 型磷钨酸负载于其上, 制备了 PW-Bis-PImBr-PMO-SBA-15 催化剂, 并运用 X 射线衍射、N2 吸附-脱附、透射电子显微镜、傅里叶变换红外光谱和热重分析等手段对其进行表征. 结果表明, 该催化剂具有 SBA-15 分子筛的有序六方孔道结构, 且负载后的磷钨酸阴离子仍保持其完整的 Keggin 结构. 在以水为溶剂, 30% H2O2 为氧化剂的苯甲醇氧化反应中, 该催化剂表现出比均相的或负载于 SBA-15 表面的 Keggin 型 HPW 更高的催化活性, 苯甲醇转化率和苯甲醛选择性分别可达 95% 和 94%. 离子液体的咪唑阳离子可调节磷钨酸阴离子的氧化-还原性能, 从而有利于提高催化剂的催化活性.

关键词: Keggin 型 12-磷钨酸, 离子液体, 周期性介孔有机硅, SBA-15 分子筛, 苯甲醇, 催化氧化, 过氧化氢

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