Catalysts based on iron, chromium, potassium and at least one rare-earth metal, their preparation and their use in dehydrogenation reactions

摘要

Catalysts are described which contain iron, chromium, potassium and at least one rare-earth metal or a rare-earth metal compound in a proportion, calculated as oxide, of 1 to 15 % by weight relative to the weight of the finished catalyst. The presence in the catalyst of a rare-earth metal oxide optionally at least partially precombined in the form of a mixed oxide, of perovskite or spinel type, with Fe, Cr, Co, Ni, Al or V, endows the catalyst with an improved activity and/or selectivity in dehydrogenation reactions of hydrocarbons, in particular of ethylbenzene to styrene.