Unimolecular cracking and the dehydrogenation of alkanes on zeolites results from direct interactions between alkanes with zeolitic protons. Theoretical studies of heterogeneous catalysis aim to predict the rates of catalyzed reactions and the distribution of products for new catalysts by properly capturing the effects of changes in catalyst structure and composition. Much progress has been made in this respect and in this work we make use of such tools. While density functional theory combined with absolute rate theory can be used to determine the intrinsic rate coefficient for these specific reactions, this static picture of the reactants and products approximates the distribution of energetically accessible states. In order to further understand the kinetics of alkane cracking on a series of zeolites, adsorption thermodynamics were calculated using Monte Carlo simulations in the canonical ensemble. In particular, we have explored the number of alkane molecules per unit mass of zeolite that are close enough to a Br�nsted-acid site to be in the reactant state for the cleavage of a specific C-C bond for both propane and butane. By combining these theoretical approaches, experimentally observed rates cane be properly interpreted.

Theoretical simulations of n-alkane unimolecular cracking on zeolites

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.