The reaction-medium transformation of catalysts of V2O5, supported or unsupported on TiO2, used for oxidn. of o-xylene to phthalic anhydride (I), is examd. Time-onstream evolution of structural and catalytic properties of V oxide are studied in a flow reactor; the +4 and +5 oxidn. states of V are characterized. The initial V catalyst undergoes first a deep redn. and then a partial re-oxidn.; this reaction is concommitiant with the spreading of the V catalyst on the TiO2 surface. Comparable selectivities and yields of I are obtained using either an unsupported or supported V2O5, indicating that a unique structure of V2O5 is not stabilized on the TiO2 surface. [on SciFinder(R)]
Role of redox dynamics in vanadium oxide on titania transformation during o-xylene selective oxidation
CENTI, Gabriele;
1990-01-01
Abstract
The reaction-medium transformation of catalysts of V2O5, supported or unsupported on TiO2, used for oxidn. of o-xylene to phthalic anhydride (I), is examd. Time-onstream evolution of structural and catalytic properties of V oxide are studied in a flow reactor; the +4 and +5 oxidn. states of V are characterized. The initial V catalyst undergoes first a deep redn. and then a partial re-oxidn.; this reaction is concommitiant with the spreading of the V catalyst on the TiO2 surface. Comparable selectivities and yields of I are obtained using either an unsupported or supported V2O5, indicating that a unique structure of V2O5 is not stabilized on the TiO2 surface. [on SciFinder(R)]Pubblicazioni consigliate
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