Single-Event Kinetic Model for 1-Pentene Cracking on ZSM-5

A single-event kinetic model for 1-pentene cracking on ZSM-5 is presented. In the kinetic model, the influence of the catalyst on the reactivity is comprehended via steric constraints in the zeolite pores. Compared to gas-phase chemistry, reaction pathways with sterically demanding olefins are excluded from the reaction network because of these constraints. The number of estimated kinetic parameters is reduced by choosing operating conditions for which double-bond isomerization and skeletal isomerization are in thermodynamic equilibrium. Thus, only cracking and dimerization remain as rate-determining steps. The data set comprises 23 different experimental conditions being varied at different residence times. From this data set, significant kinetic parameters with small confidence intervals are determined. A good parity between model and experiment was obtained, which supports the applicability of the single-event methodology to the complex reactivity of olefins cracking on ZSM-5 and gives mechanistic insight into the reaction pathways leading to the product distribution. Furthermore, the possibility to use these kinetic parameters for extrapolation purposes beyond the experimentally covered range of reaction conditions is shown.