On the Importance of Benchmarking the Gas-Phase Pyrolysis Reaction in the Oxidative Dehydrogenation of Propane

The oxidative dehydrogenation of propane (ODP) proceeds catalytically on a gas-solid interface (heterogeneous reaction) and/or in the gas phase (homogeneous reaction) via a radical chain process. ODP may therefore combine interrelated contributions from the heterogeneous dehydrogenation and gas-phase reactions, which can be initiated by a catalyst. This study demonstrates that relatively high propene and ethene selectivities (ca. 80 % and 10 %) and propane conversions (viz., 10 % at 500 degrees C) can be achieved with an empty quartz reactor, which is comparable to the performances of state-of-the-art ODP catalysts (boron-based or supported VOx). Optimization of the post-catalytic volume of a h-BN catalyst bed tested at 490 degrees C allows to increase the conversion of propane from 9 % to 15 % at a propene selectivity of 77 %, highlighting this parameter as an important variable for improving catalytic ODP performances.