In recent years, induction heating (IH) has seen increased usage in reactor designs for heterogeneous catalysis. Compared to conventional furnace heating (CFH), IH offers higher energy efficiency and facilitates the electrification of chemical processes. The synthesis of acetone from biomass-derived ethanol has garnered recent interest due to its status as a more sustainable alternative to the cumene process, which relies on fossil-fuel-based feedstocks. An iron-zinc mixed oxide has been identified as an effective catalyst for the dehydrogenation and ketonization of ethanol. The reaction is carried out at 350-500 ℃ in the presence of water vapor. Acetone and carbon dioxide are produced, and acetaldehyde, ethylene, and ethane are the main byproducts. In this study, rate data were collected under both IH and CFH, and it was found that IH achieves comparable conversion and selectivity to CFH at temperatures 25-30 ℃ lower. It was first investigated whether a similar reaction mechanism was taking place in both heating methods. Collected data were fit to a Langmuir reaction model, and trends from altering the concentration of water vapor were compared. Based on this data, it was found that the rate-limiting step is the dehydrogenation of ethanol into acetaldehyde, which then competes between the desorption and ketonization steps. Both IH and CFH fit the model and observed similar trends, suggesting that they both follow the same reaction mechanism. The superior performance of IH can be better explained by local hotspots in the catalyst bed that arise due to the oscillating magnetic field creating temperature fluctuations. It is proposed that these local hotspots enable faster reaction rates and promote water dissociation, leading to higher conversion and selectivity.
