高等学校化学学报

高等学校化学学报 ›› 1995, Vol. 16 ›› Issue (4): 608.

• 论文 • 上一篇    下一篇

Mo/USY催化剂中USY骨架结构稳定性对MoO3烧结行为的影响

牛国兴, 李全芝   

  1. 复旦大学化学系, 上海, 200433
  • 收稿日期:1994-07-31 修回日期:1994-12-25 出版日期:1995-04-24 发布日期:1995-04-24
  • 通讯作者: 李全芝
  • 作者简介:牛国兴,男,28岁,博士研究生.
  • 基金资助:

    国家自然科学基金

The effect of the Framework Stability of USY Zeolite on the Sintering of Molybdenum in Mo/USY Catalysts

NIU Guo-Xing, LI Quan-Zhi   

  1. Department of Chemistry, Fudan University, Shanghai, 200433
  • Received:1994-07-31 Revised:1994-12-25 Online:1995-04-24 Published:1995-04-24

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摘要： 应用XRD、XPS、IR、29SiMASNMR、27AlMASNMR和NO-IR吸附等手段对一系列经不同温度焙烧的Mo/USY催化剂中USY骨架结构破坏过程和Mo在USY分子筛中的烧结行为进行了研究,结果表明,Mo在USY上分散和烧结时,存在一个MO对USY分子筛骨架铝的抽提过程。Mo在USY分子筛表面分散时,抽提该分子筛骨架Si(2Al)中少量的Al,但当焙烧温度升高,Mo开始烧结时,Mo主要抽提骨架中Si(1Al)中的Al;MoO3在USY分子筛上的烧结首先表现为Mo对该分子筛骨架铝的抽提,导致分子筛严重脱铝和结构崩塌。一旦分子筛结构破坏,MoO3则迅速与Al3+结合并烧结成Al2(MoO4)3.

关键词: Mo/USY, USY脱铝, Mo烧结

Abstract: Mo/USYsamples,prepared by conventional impregnation with(NH4)6Mo7O24solution and calcined at 300,400,500,600℃,were characterized,by XRD,XPS, 29Si MAS NMR and 27AlMASNMR,acidity measurement with IR-TPDand NO chemisop tion.The results obviously show that Mo incorporation induces an aluminium extraction from the framework of zeolite.When molybdenum is dispersed over the support at low calcination temperature(<400℃),it mainly extracts aluminium of Si(2Al)in the framework of USYzeolite. However,sintering at a high calcined temperature,molybdenum mainly extracts aluminium of Si(1Al) from the framework.There are two steps in the process of sintering of molybdenum in Mo/USY catalysts. First, molybdenum makes USY zeolite dealuminate sharply and destroy the framework,and then immediately forms bulk Al2(MoO4)3with the non-framework aluminium originated from the framework of USYzeolite.

Key words: Mo/USY, Dealumination of USY, Sintering of Mo

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