Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures.