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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