物理化学学报 >> 1997, Vol. 13 >> Issue (06): 554-559.doi: 10.3866/PKU.WHXB19970614

研究论文 上一篇    下一篇

草酸脱铝Y沸石的性质

何静,李宣文,刘兴云,裴站芬,佘励勤   

  1. 北京大学化学与分子工程学院,北京 100871
  • 收稿日期:1996-11-06 修回日期:1997-01-30 发布日期:1997-06-15
  • 通讯作者: 李宣文

Properties of Y Zeolite Dealuminated by Oxalic Acid

He Jing,Li Xuan-Wen,Liu Xing-Yun,Pei Zhan-Fen,She Li-Qin   

  1. College of Chemistry and molecular Engineering,Peking University,Beijing 100871
  • Received:1996-11-06 Revised:1997-01-30 Published:1997-06-15
  • Contact: Li Xuan-Wen

摘要:

草酸与草酸铵脱铝的Y沸石,具有八面沸石结构和良好的结晶度. 羟基红外光谱和吡啶吸附的红外光谱表明,在脱铝Y沸石的骨架中存在着铝空位. 这种缺铝Y沸石中由3550cm-1表征的小笼羟基更具开放性,但稳定性较差,在升温过程中,它比3640cm-1表征的大笼羟基更易脱除. 吡啶与CO双探针分子红外光谱的研究表明,升温脱羟基过程伴随着与Lewis酸有关的非骨架铝的生成. 低温N2吸附的结果显示,缺铝Y沸石中还有远远大于铝空位的二次孔存在,这可能是升温过程中结构重排造成的.

关键词: 缺铝Y沸石, 骨架铝空位, 结构二次孔, 化学脱铝

Abstract:

The Y zeolite dealumiated by oxalic acid and ammonium oxalate maintained the faujasite structure with a good crystallinity. The OH-IR spectra and chemical analysis showed that there were aluminum vacancies in the framework of the dealuminated Y zeolite. In such a dealuminated Y zeolite, the hydroxyls represented by 3550cm-1 was accessible to pyridine, while not so stable as the hydroxyls represented by 3640cm-1 when they were heated in vacuum. The IR spectra of double probes of Pyridine and CO illustrate the production of extra-framework aluminum species which are related to Lewis acid sites in the process of dehydroxylation. The results of N2 adsorption at low temperature suggest the existence of secondary pores which are much larger than the aluminum vacancies, and this probably resulted from the structure reconstruction.

Key words: Dealuminated Y zeolite, Aluminum vacancy, Secondary pores, Chemical dealuminization