Transient Methods\nto Intensify the Synthesis of Ethyl\nLevulinate

Levulinic acid, 4-oxopentanoic acid, is considered an\nattractive\nbuilding block with widespread applications in various fields together\nwith its derivatives. They can be used as lubricants, printing inks,\ncorrosion inhibitors, products for personal care, and for drug delivery.\nIn the present paper, attention was focused on the esterification\nof levulinic acid with ethanol promoted by a heterogeneous acid catalyst,\nin particular, an ion-exchange resin, namely, Amberlite IR120. The\nreaction was conducted in a continuous device by applying transient\nmethods. This approach led to very attractive outcomes when compared\nto the traditional fixed bed reactor as water is removed continuously\nand the equilibrium is shifted, obtaining full conversion. A significant\ndifference in performance is evident between the two operational modes.\nWith a classical packed bed reactor, the maximum levulinic acid conversion\nwas 31% at 363 K and a flow rate of 3.33 × 10<sup>–8</sup> m<sup>3</sup>/s, while by applying the transient method under the\nsame conditions, the levulinic acid conversion rose to 94%. Kinetic\ntests were performed at different temperatures, varying the volumetric\nflow rate during the tests. Nearly complete conversion of levulinic\nacid was achieved in experiments conducted at temperatures of 313,\n323, 343, and 363 K. Furthermore, high conversion, reaching 90%, was\nalso attained at a lower temperature of 293 K. The experimental data\nwere successfully interpreted with a mathematical model to retrieve\nkinetic and thermodynamic parameters. Finally, the fluid-dynamic characterization\nof the system demonstrated that the reactor worked with plug-flow\nbehavior.