(451d) Investigating Reaction Pathway Shifts in Propane Dehydrogenation Under Induction Heating

Propane dehydrogenation (PDH) is a thermodynamically limited and kinetically sensitive reaction widely used to produce propylene, a key monomer in industrial chemistry. Conventional PDH processes, typically conducted using externally heated fixed-bed reactors, face challenges including poor heat transfer, catalyst deactivation, and formation of undesired byproducts such as ethylene, ethane, and methane. Radiofrequency (RF) induction heating (IH) offers a promising alternative by enabling rapid, volumetric heating through ferromagnetic susceptors mixed into the catalyst bed. Our prior work showed that while propane conversion remained comparable between IH and conventional furnace heating (CFH), IH consistently led to significantly higher propylene selectivity and suppressed side product formation.

To decouple thermal and non-thermal effects, we conducted PDH experiments under CFH with an externally applied magnetic field, isolating the role of magnetic influence independent of inductive heating. These control experiments revealed no measurable change in catalytic activity or selectivity under magnetic field application alone, indicating that the improved performance observed under IH is not attributable to magnetic field effects. Instead, based on changes in product distribution and supported by mechanistic literature, we hypothesize that the enhanced selectivity under IH arises from a reduction in the energy barrier for propylene desorption. Facile desorption likely prevents further dehydrogenation or cracking of adsorbed propylene, thereby shifting the product selectivity favorably and reducing the likelihood of coke formation.

To validate this hypothesis and further elucidate the role of induction heating in altering surface chemistry, we will present catalytic characterizations including temperature-programmed desorption (TPD) of propylene and hydrogen to probe desorption behavior, thermogravimetric analysis (TGA) to quantify coke accumulation, and temperature-programmed reduction (TPR) to assess catalyst reducibility and electronic structure in CFH and IH. These studies aim to elucidate how RF-driven thermal gradients at the nanoscale can modulate catalytic pathways, enabling the rational design of catalysts and reactor systems optimized for induction-heated environments in on-purpose olefin production.