Microwave‐assisted highly efficient and sustainable synthesis of alkyl levulinates over acid‐functionalized nitrides

Abstract Acid functionalized nitrides, including sulfonic‐functionalized graphitic carbon nitride (SGCN) and sulfonic‐functionalized boron nitride (SBN), were synthesized and used successfully in the microwave‐assisted conversion of furfuryl alcohol (FA) into alkyl levulinates. Catalytic materials were characterized for their structural, morphological, and acid properties as well as for the synthesis of methyl levulinate (ML), chosen as model reaction. Reaction conditions, including temperature, time, and amount of catalyst, were optimized under microwave irradiation and pointed to SGCN providing optimum catalytic performance. At 140 °C, FA was fully converted in just 2 min, yielding ML in almost quantitative selectivity (98%). Additional experiments carried out by changing the catalyst/substrate ratio, proved the suitability of SGCN towards process intensification. Finally, a substrate scope evaluation demonstrated that various alcohols – ethanol, butanol, and isopropanol – were equally effective for synthesizing the corresponding alkyl levulinates, achieving 99% selectivity at 60% to 99% conversion.