Coke toxicities, descriptors of the deactivating effect of coke on microporous and desilicated mordenite zeolite.

In this contribution, the formation and growth of coke and its consequences on the mordenite catalyst were investigated on microbalance, through the transformation of propene at 350 °C. The kinetic results revealed that a higher initial coking activity leads to faster initial deactivation and there is a proportionality between the rate of coke formation and the rate of its deactivation. The increase of propene pressure supports the rate of coke formation rather than its growth to heavier and more aromatic molecules. This self-deactivation results from the inhibition of Brønsted acid sites predominantly by pore blockage. Combining the residual acidity and coke composition data makes it possible to estimate the contribution of pore blocking and site poisoning. These two deactivation modes are related and occur simultaneously. [ABSTRACT FROM AUTHOR]