Sustainable Continuous Synthesis of Methyl Levulinate in a Rotating Catalytic-Bed Recycle Reactor: Reaction Kinetics, Process Scale-Up, Engine Performance, and Exhaust Emission

Abstract

This is the first report on an intensified, energy-efficient, and environmentally sustainable continuous conversion of fructose to a drop-in biofuel, viz., methyl levulinate (ML), employing a UV and tungsten-halogen irradiation (UVTH)-equipped continuous-flow rotating catalytic-bed recycle reactor (UTCRCR). The ML synthesis deploying an acidic (Amberlyst 15) photocatalyst (TiO 2 ) (APC) at optimal batch reactor conditions, viz., 80 min, 70 °C, 0.005:0.15 mol/mol fructose solution:methyl alcohol, and 9 wt % APC employing innovative UVTH irradiations, rendered 83.2% fructose conversion with high 74.54 mol % ML yield. The Eley−Rideal heterogeneous reaction kinetics represented a much lower activation energy (34.23 kJ/mol) than previous reports. The ML yield could be further intensified to 80.06 mol % with the employment of the UTCRCR saving 63.33% energy as compared to conventional heating. The continuous ML synthesis with recycle mode was scaled up to 267.64 kg ML/h (80.9 mol % ML yield) attaining 90% overall fructose conversion. The life cycle analysis of the process and engine exhaust emission analysis could confirm the overall sustainability.