A thermodynamic analysis of the reaction systems involved in the generation of propene from ethanol

The Gibbs free energy minimization method was employed to investigate the synthesis of propene from ethanol. Feed composition (H2O and N-2 presence and concentration) and reaction conditions (temperature and pressure) were used as variables to analyze the equilibrium of the intermediate and global reactions. High temperatures, low pressures, and medium to high concentrations of water are positive for the production of propene: this ethanol transformation is thermodynamically favorable as well as all of its intermediate reactions, with exception of the Meerwein-Ponndorf-Verley reduction. Indeed, this and ethanol dehydration seem to be deviations from the main path of reaction, leading to lower selectivities to propene while producing acetone and ethene, respectively. Therefore, local minimum Gibbs free energy might trap the reaction from producing more propene, depending on the catalyst employed and how it affects the kinetics of the system.