物理化学学报 >> 1986, Vol. 2 >> Issue (06): 519-524.doi: 10.3866/PKU.WHXB19860607

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氧氯化催化剂的组成和分散状态

谢有畅; 蔡小海; 桂琳琳; 唐有祺   

  1. 北京大学物理化学研究所
  • 收稿日期:1985-08-07 修回日期:1986-01-27 发布日期:1986-12-15

DISPERSION AND CHEMICAL COMPOSITION OF ACTIVE COMPONENT IN OXYCHLORINATION CATALYST

Xie Youchang; Cai Xiaohai; Gui Linlin; Tang Youqi   

  1. Institute of Physical Chemistry; Peking University
  • Received:1985-08-07 Revised:1986-01-27 Published:1986-12-15

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摘要： 对氧氯化催化剂C_uCl_2/γ-Al_2O_3的XRD相定量和差热分析表明, 倦化剂的活性组分C_uCl_2以单层分散于载体表面, 最大分散量(阈值)约为O.13gC_uCl_2/gγ-Al_2O_3(γ-Al_2O_3比表面约为170 m~2g~)。TG, XRD和HCI的化学吸附实验表明, 催化剂中活性组分的存在状态和化学组成(CI/Cu比)可随催化剂的处理条件和所处气氛而变化; 在HCl气氛下CI/Cu<2的催化剂可恢复Cl/Cu比为2或大于2; 倦化剂吸附HCl的位置在未被CuCl_2覆盖的γ-Al_2O_3表面上。

Abstract:

Recently, the models of active phases (or sites) of copper-based oxychlorination (OC) catalyst have been proposed~[4,6,9]. Unfortunately, up to present how the active component dispersing onto a carrrier has not been studied in detail yet, and its real chemical composition is not unanimous either. In previous paper~[7] we proposed some ideas on that the composition, structure and activity of catalyst vary with the diffrent atmospheres. Here we will discuss them in another way and provide more experimental evidences.
1. DISPERSING OF ACTIVE COMPONENT
Quantitative XRD phase analysis indicated that until the CuCl_2 content to 0.13g/gγ-Al_2O_3 (surface area of the carrier is about 170 m~2g~(-1)) there are no peaks of crystalline CuCl_2 in the XRD pattern and the pattern is similar to that of the carrier. Amounts of crystalline CuCl_2 increase linearly with the raise of CuCl_2 content in the higher Cu content catalysts and the crystalline phase line does not pass through the origin. This result shows that the active component does not form crystallite in the lower Cu content catalyst. It must disperse onto surface of the carrier and the utmost dispersion capacity (threshold) on such carrier is about 0.13g/gγ-Al_2O_3.
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