Levulinic acid esterification with ethanol to ethyl levulinate production over solid acid catalysts

Levulinic acid is considered as a versatile building block because it can be used for the synthesis of several organic chemicals. In particular, its esterification with ethanol produces ethyl levulinate that can be used as diesel miscible biofuel (DMB), preventing global warming by decreasing atmospheric CO2 generated from the consumption of fossil fuels. This article explores the use of two groups of solid acid catalysts (sulfated oxides and zeolites with different pore structures) in the esterification of levulinc acid with ethanol aiming for ethyl levulinate production. It was found that while there is a correlation between the number of acidic sites and activity for the sulfated oxides, the same is not true for the studied zeolites where the pore channels play a more important role. Among the catalysts tested, Amberlyst-15 and sulfated SnO2 showed a remarkable high yield of ethyl levulinate that was probably due to the strong acidity provided by SO3H functional groups and SO4 species, respectively.

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► The activity of sulfated oxides for levulinic acid esterification correlates with their acidity.
► Successive sulfations of SnO2 increase its acidity and activity.
► The pore structure of zeolites plays a role more important than that of the acidity.
► Amberlyst-15 presents a good activity and reusability.