Paraffin dehydrocyclization: Distribution of aromatic products obtained with “nonacidic” supported Pt catalysts

Abstract

The distribution of the isomeric aromatic products from the dehydrocyclization of ten C 8C 9 paraffins over a 0.6% Pt catalyst supported on “nonacidic” alumina has been determined. The aromatic isomers obtained experimentally are those predicted for a direct cyclization to the six-membered ring structure. The participation of other size ring intermediates recently proposed to explain dehydrocyclization over chromia is not required to explain our results with a platinum catalyst. The very small amount of aromatic isomers not expected from direct six-membered ring formation probably arise from dual functional catalytic isomerization of the reactant prior to cyclization. The aromatic product distribution suggests that a “geminal dialkylcyclohexane intermediate” contributes to the reaction pathway when such structures are allowed by a six-membered ring closure.