Alkane activation over acidic zeolites: the first step.
The heterogeneous acid-catalyzed activation step of alkanes leading to the reaction intermediates (carbocationic or alkoxy species) was up to now the matter of a longstanding controversy. Gas chromatography and online mass spectroscopy measurements show that H(2) and methane are formed over H-zeolites, whereas HD and CH(3)D are formed over D-zeolites as the primary products in the reaction with isobutane. These results indicate that sigma-bond protolysis by strong acid sites is the first step for hydrocarbon activation on these catalysts at mild temperatures (473 K), in analogy to the activation path occurring in liquid superacid media.
Louis
Benoit
B
Laboratoire des Matériaux Surfaces et Procédés pour la Catalyse, Member of ELCASS (European Laboratory for Catalysis and Surface Sciences), UMR 7515 CNRS, 25 rue Becquerel 67087 Strasbourg Cedex 2, France.
Pereira
M Maciel
MM
Santos
Fabiana M
FM
Esteves
Pierre M
PM
Sommer
Jean
J