Optimally designed reactive distillation processes for eco-efficient production of ethyl levulinate

BACKGROUND: Ethyl levulinate (EL) is an important chemical that can be used as a bio-based replacement of fuel additives such as methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME). EL production from lactic acid and ethanol is a viable option, as both precursors can be obtained from biomass. However, the problem of EL production by esterification is that this reaction is hindered by the chemical equilibrium limitations and the boiling points ranking, which is not the most favorable. RESULTS: This study provides novel optimally designed reactive distillation (RD) processes for the production of EL, taking into account costs, environmental impact and safety. The thermally coupled RD process is the most appealing, with the lowest energy use (1.667 MJ kg⁻¹ EL), minimal investment cost, major energy savings (up to 54.3% lower than other RD processes), reduced environmental impact (up to 51% lower ECO99 index value) and similar safety as other RD processes considered (less than 2% differences in the individual risk (IR) indicator). CONCLUSION: The multi-objective optimization approach used here showed its robustness, practicality and flexibility to provide multiple optimal designs of intensified processes that are economically attractive, environmentally friendly and inherently safe.