(569af) Preparation and Characterization of Fe3O4/Natural Sulfonated Zeolite As Catalysts in the Esterification Reaction of Glycerol to Triacetin

The synthesis and characterization of Fe₃O₄/natural sulfonated zeolite as catalysts and their use in the glycerol to triacetin esterification process was studied. In this work, Fe₃O₄/natural sulfonated zeolite catalysts will be synthesized and then characterized using FTIR, XRD, and gravimetric acidity testing (ammonia vapor adsorption). The impact of catalyst mass variation and reaction time on triacetin selectivity value in the esterification reaction of glycerol to triacetin will also be investigated. Three steps were involved in the creation of Fe₃O₄/natural sulfonated zeolite catalysts: the first involved the synthesis of natural zeolite, followed by the activation of sulfonated zeolite and the coprecipitation-based impregnation of Fe₃O₄ on sulfonated zeolite. Furthermore, the catalyst was tested for its catalytic activity in the esterification reaction of glycerol with acetic anhydride into triacetin at mass variations of 3%, 5%, and 7% for reaction times of 30, 45, 60, 75, and 90 minutes. The characterization results using FTIR showed four main absorption bands at 1049.28, 1219.01, 794.67, and 447.49 cm^-1 for sulfonated natural zeolite and 570.93 cm-1 for the Fe-O bond of magnetite. XRD characterization results showed that sulfonated natural zeolite was dominated by mordenite minerals at 2θ = 10.22^o, 20.15^o, and 22.88^o and confirmed the presence of Fe₃O₄ compound at 2θ = 30.58^o, 35.96^o, 43.81^o, 53.08^o, 57.6^o, and 63.26^o with cubic crystallographic planes. The acidity test results by gravimetric method showed that the impregnation of Fe3O4 compound on sulfonated natural zeolite had a total acidity value of 7.23 mmol/gram. The catalytic activity test in the esterification reaction of glycerol with acetic anhydride gave a triacetin selectivity value of 73.96% for a reaction time of 75 minutes and 73.18% selectivity with a catalyst weight of 7%.