Fe2(SO4)3-Catalyzed Levulinic Acid Esterification: Production of Fuel Bioadditives

In this work, we developed a route to synthesize fuel bioadditives based on simple and inexpensive commercial catalyst: iron(III) sulfate. This process is an alternative to the traditional Bronsted acid catalysts, avoiding steps to neutralize the catalyst, which generates a large amount of effluents and residues. High conversions (ca. 90%) and selectivity (90-97%) for alkyl esters of levulinic acid with carbon chain ranging from C-6-C-9 were obtained, when Fe-2(SO4)(3) was the catalyst. The role of each component catalyst system was studied, with a special attention on the reaction temperature, stoichiometry of reactants and catalyst concentration. We investigate the catalytic activity of others commercial transition metal salts (i.e., Fe-2(SO4)(3), FeCl3, CuSO4, FeSO4, MnSO4, NiSO4). Although soluble, the Fe-2(SO4)(3) catalyst was easily recovered by silica column chromatography, in the same step of products purification, and reused without loss activity. The use of renewable raw material and an efficient, inexpensive and recyclable catalyst are the main positive features of this process.