高等学校化学学报

高等学校化学学报 ›› 1995, Vol. 16 ›› Issue (1): 111.

• 论文 • 上一篇    下一篇

WO3/ZrO2和MoO3/ZrO2固体超强酸体系研究

高滋, 陈建民, 姚宇宁, 华伟明, 缪长喜   

  1. 上海复旦大学化学系, 上海 200433
  • 收稿日期:1994-03-21 修回日期:1994-06-17 出版日期:1995-01-24 发布日期:1995-01-24
  • 通讯作者: 高滋,女,60岁,教授.
  • 作者简介:高滋,女,60岁,教授.
  • 基金资助:

    国家基础研究重大项目;中国石油化学工业总公司发展基金

Studies on WO3/ZrO2and MoO3/ZrO2Solid Superacid Sytems

GAO Zi, CHEN Jian-Min, YAO Yu-Ning, HUA Wei-Ming, MIAO Chang-Xi   

  1. Department of Chemistry, Fudan University, Shanghai, 200433
  • Received:1994-03-21 Revised:1994-06-17 Online:1995-01-24 Published:1995-01-24

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摘要： 研究了浸渍偏钨酸铵和仲钼酸铵的无定形ZrO2在焙烧过程中钨和钼氧化物表面分散和晶相变化情况。发现于350℃焙烧后钨、钼仍以多聚酸根形式分散于ZrO2表面,用XRD法测定的"视阈值"远大于按WO3和MoO3计算的单层分散容量。800℃焙烧后钨和钼以WO3和ZrMo2O8的形式分散于ZrO2表面上,用XRD方法测定的"视阈值"与WO3和ZrMo2O8的单层分散容量相近。Hammett指示剂法和正戊烷异构化反应结果表明,WO/ZrO2体系的Ho可达-13.8-14.5,MoO3/ZrO2体系的Ho可达-12.0-12.7.800℃焙烧的WO3和MoO3含量在单层分散容量附近的样品超强酸性最强。

关键词: 固体超强酸, WO3/ZrO2, MoO3/ZrO2, 酸性表征

Abstract: The dispersion and crystal phase changes of tungsten and molybdenum compounds on samples prepared by impregnating ammonium metatungstate and ammonium paramolybdate on amorphous ZrO2during the calcination have been investigated in detail. It was found that after the calcination at 350℃ tungsten and molybdenum existed in the form of isopolyacidic anions,so that the apparent dispersion thresholds determined by XRD method were much greater than the calculated monolayer dispersion capacities of WO3and MoO3on ZrO2.After calcination at 800 ℃ the Wand Mo dispersed on ZrO2transformed into the form of WO3on ZrMo2O8,and the experimental apparent dispersion thresholds became approximate to the monolayer dispersion capacities of WO3and ZrMo2O8on ZrO2.The results of measurements by Hammett indicator and n-pentane isomerization methods showed that Ho of the WO3/ZrO2systems reached-13.8--14.5 and that of the MoO3/ZrO2systems-12.0--12.7,and the samples containing the amounts of WO3and MoO3close to their monolayer dispersion capacities and calcined at 800℃ displayed stronger superacidity.

Key words: Solid superacid, WO3/ZrO2, MoO3/ZrO2, Characterization of acidity

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