WO3-modified KIT-6 catalysts synthesized via a non-hydrolytic sol–gel method for glycerol dehydration to acrolein

Abstract

The expansion of biodiesel production has generated a surplus of glycerol. The valorization of this renewable by-product into value-added chemicals has therefore gained increasing interest. This study presents a systematic investigation of WO₃/KIT-6 catalysts prepared via a non-hydrolytic sol–gel (NHSG) method for glycerol dehydration to acrolein. Catalysts with 5–35 wt% WO₃ were synthesized and systematically characterized. XRD confirms the formation of monoclinic WO₃ across the investigated samples. The 25 wt% WO₃/KIT-6 catalyst exhibits the highest medium-strength acid site concentration (204 μmol NH₃ per g), intrinsic acidity (0.56 μmol NH₃ per m²), and a Brønsted/(Brønsted + Lewis) ratio of 0.67. Under the studied reaction conditions, this catalyst achieves 83% glycerol conversion and 43% acrolein selectivity. The results indicate that an optimal balance between medium-strength acidity and mesostructural properties governs acrolein selectivity and catalyst stability.