Dehydrogenation of propane over Pt/KL catalyst Investigating the role of L-zeolite structure on catalyst performance using isotope labeling

Dehydrogenation of propane using an equimolar mixture of propane-do and propane d(8) was investigated over 1%Pt/KL and 1%Pt/SiO2 at atmospheric pressure and different reaction temperatures A normal kinetic isotope effect exists (k(H)/k(D) = 1 4-1 5) when the reaction is conducted on Pt/KL at different temperatures (400 500 and 600 degrees C) suggesting that C-H bond activation is involved in the kinetically relevant steps Furtheremore there is hardly any H-D exchange in the recovered propane during dehydrogenation at temperatures above 400 degrees C suggesting that adsorption and subsequent dehydrogenation of propane are essentially irreversible and that C-H bond activation is the rate determining step Unlike the case of hexane aromatization the unique structure of L-zeolite does not help in controlling the entry of propane molecules Into the lobes of the L-zeolite containing the active sites hence bimolecular reactions do occur leading to coke formation and catalyst deactivation (C) 2010 Elsevier B V All rights reserved