Effect of Fe and Ni loading in Fe-Ni supported on activated carbon catalyst on glycerol acetylation to acetins

Abstract

Sustainable valorisation of glycerol into high-value products has gained significant attention as a promising alternative, offering a greener and more economically sustainable pathway to produce chemicals, fuels, and biopolymers. Acetylation of glycerol is one of the promising routes for producing valuable acetins, which are widely used as biofuels, plasticizers and solvents. In this study, Fe-Ni/AC catalysts were synthesized with different metal loading via wet impregnation method and characterized using FT-IR, SEM-EDX, TGA, BET and NH₃-TPD. The catalysts were subjected to an acetylation reaction under a microwave assisted condition at 90 ℃ for 60 min and the performance was demonstrated based on glycerol conversion and the production of acetins, specifically monoacetin (MA) and the combined yield of diacetin and triacetin (DA+TA). From the characterization results, the impregnated iron-nickel significantly impacts the physicochemical properties of the studied bimetallic catalyst. Increasing the metal loading reduced the catalyst’s surface area but enhanced the concentration of acid sites which as a result improved the glycerol conversion to MA and the combined yield of DA and TA. Among the various catalysts investigated, the 5Fe-5Ni/AC catalyst that contain 10 wt% of total metal loading, demonstrated highest catalytic performance under moderate reaction conditions with 505.08 m²/g and 16,061.62 µmolg⁻¹ of surface area and strong acid sites, respectively. The catalyst’s high acidity resulted in high glycerol conversion (88.8 %) with 50.5 % MA yield and 38.3 % of DA+TA. This study highlights the potential of Fe-Ni/AC catalysts for glycerol acetylation. A novel metal combination for the development of solid acid heterogeneous catalyst with improved catalytic performance.