SPONTANEOUS REGENERATION OF IRON POTASSIUM OXIDE CATALYSTS IN THE PRESENCE OF WATER VAPOR.

Spontaneous regeneration of the catalysts consists essentially of the oxidation of intermediate products, either physically adsorbed or chemically bound to the catalyst, by oxygen of water or by oxygen of the reaction medium during the formation of carbonaceous deposits. As exemplified by iron potassium oxide catalysts, it has been shown that hydrolysis of intermediate carbidelike compounds makes the principal contribution to spontaneous regeneration. On the basis of this investigation, extremely efficient spontaneously regenerating and continuously operating iron-chromium-potassium catalysts have been developed for the dehydrogenation of ethylbenzene to styrene. The course of spontaneous regeneration depends to a substantial extent on the nature of the intermediate products during the coking of the catalysts. Thus in coking by the carbide cycle mechanism the intermediates are carbidelike compounds.