物理化学学报 >> 2000, Vol. 16 >> Issue (02): 126 -132 .doi: 10.3866/PKU.WHXB20000207

研究论文 上一篇    下一篇

钾助催化剂与Fe3O4相互作用行为的XRD表征

祝以湘, 柴运宙, 刘正阳, 黄素梅, 程向明   

  1. 厦门大学固体表面物理化学国家重点实验室,化工系,物理化学研究所,厦门 361005|吉林化学工业股份有限公司有机合成厂,吉林 132022
  • 收稿日期:1999-04-23 修回日期:1999-07-26 发布日期:2000-02-15
  • 通讯作者: 祝以湘

XRD Characterization of Interaction between Potassium Promoter and Magnetite

Zhu Yi-Xiang, Chai Yun-Zhou, Liu Zheng-Yang, Huang Su-Mei, Cheng Xiang-Ming   

  1. State Key Laboratory for Physical Chemistry of the Solid Surfaces Department of Chemical Engineering Institute of Physical Chemistry,Xiamen University,Xiamen 361005
  • Received:1999-04-23 Revised:1999-07-26 Published:2000-02-15
  • Contact: Zhu Yi-Xiang

摘要:

XRD研究表明 ,作为乙苯脱氢催化剂中的氧化铁活性组分 ,具有反式尖晶石结构的Fe3O4 比刚玉型的α-Fe2O3 更易与钾助催化剂发生相互作用 :α Fe2O3-K2O需经850℃煅烧才能生成多铁酸钾 ,但在Fe3O4 -K2O体系中只需700℃即可.而且 ,钾还可抑制Fe3O4 被氧化为α-Fe2O3 的进程 ,在空气中 ,Fe3O4 只需300℃煅烧即可明显转化为α-Fe2O3 ,但同样的转化在Fe3O4-K2O体系中要经700℃煅烧才会明显地发生.实验结果表明 ,某种形态的多铁酸钾可能是催化剂中的储钾相.

关键词: 乙苯, 脱氢, 氧化铁, 催化剂, 钾助催化剂, 铁酸盐

Abstract:

Interactions of the potassium promoter with different kinds of iron oxide as the active component of the catalyst for ethylbenzene dehydrogenation we re investigated and compared with each other. By means of XRD method, it was found that magnetite in the form of the inverse spinel structure interacted easily with the potassium promoter to form potassium polyferrate in comparison to hematite with the corundum structure. In the Fe3O4 K2O system, the phase of potassium polyferrate could be formed at temperature of ~700℃,while for the α Fe2O3 K2 O system, the temperature as high as ~850℃was required for the formation of the potassium polyferrate phase. Moreover, incorporation of the potassium promoter in to the magnetite(Fe3O4) would be in favor of inhibiting the oxidation of Fe3O4 t o α Fe2O3 in the process of calcination in air, as evidenced by the experimental fact that pure Fe3O4 could be converted into α-Fe2O3 by calcination in air a t a temperature as low as ~300℃,whereas for the system of Fe3O4 K2O (10%),a calcination temperature not lower than ~700℃was required for realizing this conversion. Thus, it could be suggested that the potassium polyferrate was probable to serve as a storage phase for potassium in the catalyst of ethylbenzene dehydrogenation to styrene. 

Key words: Ethylbezene, Dehydrogenation, Iron oxide, Catalyst, Potassium promoter, Ferrate