Valorization of pure and biodiesel-derived refined crude glycerol to renewable acetol over copper-based catalyst: Effect of operating conditions and catalyst stability

Acetol is a key intermediate in the aldol condensation of biomass-derived furans, enabling the production of carbon chains within the aviation fuel range. This work proposes glycerol, a biomass-derived by-product from biodiesel production, as a renewable feedstock for acetol production. The catalytic performance of a CuAl catalyst was evaluated in the gas phase dehydration of glycerol, focusing on the influence of temperature (200–300 °C), catalyst weight to glycerol mass flow ratio (10–50 gCatalyst min gGlycerol−1), and carrier gas to liquid ratio (200–600 m3GasSTP m3Liquid−1). Both pure and biodiesel-derived refined crude glycerol were used as feedstock. Long-term stability experiments assessed the evolution of catalytic activity and physicochemical properties over time. A great activity was obtained under conditions of 250 °C, 30 gCatalyst min gGlycerol−1, and 400 m3GasSTP m3Liquid−1 with pure glycerol after a time-on-stream (TOS) of 2 h (95.1 % glycerol conversion and 564 mgAcetol gGlycerol−1). Stability studies provided good catalytic results after a TOS of 52 h using pure glycerol (72 % glycerol conversion and 266 mgAcetol gGlycerol−1) and demonstrated that coke deposition was responsible for catalyst deactivation. The use of refined crude glycerol proved to be highly effective in the first hours of the reaction (98.7 % glycerol conversion and 570 mgAcetol gGlycerol−1 for a TOS of 2 h), however, rapid deactivation was observed due to solids deposition. This catalytic route highlights the feasibility of valorization of biomass residues for producing renewable acetol, a promising precursor for sustainable aviation fuel (SAF).