from first principles PP-I-1

PP-III-104Cr, V and Pt in O 2 -Free Propane Dehydrogenation: Who Wins and Why?Sokolov S., Stoyanova M., Rodemerck U., Linke D., Kondratenko E.V.Leibniz-Institut für Katalyse e. V. an der Universität Rostock,Albert-Einstein-Str. 29 AD-18059 Rostock, Germanysergey.sokolov@catalysis.deContinuously growing demand for propylene drives intense exploration of new productionprocesses or improving the existing ones. Catalytic non-oxidative dehydrogenation (DH) ofpropane is a promising alternative to FCC currently used for commercial production ofpropylene. In this study we explore the potential of highly dispersed VO x species supportedon alumina, silica and various Si-Al mixed oxides in the DH reaction. Particular attention waspaid to the fundamental factors governing catalysts stability within a single DH stage and overseveral DH/regeneration cycles. In this context, the influence of the support acidity oncatalytic performance was studied.Compared to industrially relevant CrO x - and Pt-SnO x -based catalysts (also prepared in thisstudy), several catalysts containing supported VO x species showed higher activity and betteron-stream stability. For instance, an initial propylene yield above 20% was achieved onVO x /MCM-41 and even above 25% on VO x /Siral-10 (Figure). Moreover, VO x /Siral-10showed higher on-stream stability in shorter DH stages (5 h) than all other catalysts.Figure C 3 H 6 yield in 24h-DH cycles over VO x /MCM-41 (◦), CrO x /MCM-41 (•), Pt-SnO x alumina (•) andin 5h-DH cycles over VO x /Siral 10 (▲), VO x /MCM-41 (◦), VO x /Siral 70 (▲) at 823 K.In-situ UV/Vis and TPO experiments indicate that buildup of coke and structural changes inthe active metal oxide species are the two phenomena responsible for the catalystsdeactivation in a single DH stage and over a sequence of DH/regeneration cycles. Thecatalytic performance will be discussed in light of characterisation results to elucidatefundamental structure-activity relationships in the DH process.264