高等学校化学学报 ›› 1997, Vol. 18 ›› Issue (3): 342.

• 论文 • 上一篇    下一篇

NaY 沸石草酸脱铝

刘兴云, 张旭政, 李宣文   

  1. 北京大学化学系, 北京, 100871
  • 收稿日期:1996-03-19 出版日期:1997-03-24 发布日期:1997-03-24
  • 通讯作者: 刘兴云, 男, 58岁, 教授.
  • 作者简介:刘兴云, 男, 58岁, 教授.
  • 基金资助:

    国家自然科学基金

Dealumination of NaY Zeolite with Oxalic Acid

LIU Xing-Yun, ZHANG Xu-Zheng, LI Xuan-Wen   

  1. Department of Chemistry, Peking Universikty, Beijing, 100871
  • Received:1996-03-19 Online:1997-03-24 Published:1997-03-24

摘要: NaY沸石用草酸溶液脱Al,随草酸用量增加,脱Al度增加,结晶度下降;但脱Al20%仍能保持95%以上的高结晶度.实验结果表明,脱Al量和H+用量呈线性关系,斜率近似0.25;C2O42-有促进脱Al的作用.脱Al过程中沸石结晶度的保持依赖于脱Al体系的缓冲作用.由草酸的电离平衡和络合平衡构成的脱Al体系可提供最佳脱Al条件.脱Al的沸石产物带有羟基“窝”八面佛石骨架,加热30O℃以上可使羟基“窝”失水,形成有大量二次孔结构的扩孔Y沸石.

关键词: NaY沸石, 草酸, 脱Al, 羟基&ldquo, 窝&rdquo, 二次孔

Abstract: The reaction of NaYzeolite with an aqueous oxalic acid solution under mild conditions yields zeolite with framework containing hydroxyl nests which are dewatered to lead tothe formation of the secondary pore when the zeolite is heated above 300℃.As the oxalicacid feed increases, the degree of dealumination of the zeolite increases, the crystallinity isreduced, but about 2O% framework aluminium is removed retaining 95% crystallinity whichdepends mainly on buffering of the system of the zeolite dealumination.There is a very goodlinear relationship with a slope of about 0.25 between mole numbers of the aluminium removed from the zeolite framework and those of the H+ depleted during the reaction of NaYwith oxa1ic acid.This result indicates that the eaction of an aqueous oxalic acid solution withNaYis stoichiometric by four H+ attack on one aluminium of the framework.

Key words: NaY zeolite, Oxalic acid, Dealumination, Hydroxy nests, Secondary pore

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