Ethyl levulinate production from agricultural residue through tin oxide with grafted propylsulfonic Faujasite catalysis

A novel combination of strong Brønsted acidity (B), from propyl sulfonic acid functionalized on H–Y zeolite (HY-PrSO3H); Lewis acidity (L), by dispersion of SnO2; and confinement control showed high reactivity and selectivity in the conversion of cellulose to ethyl levulinate (EL). An optimal catalyst for EL formation was found by combining the Faujasite (FAU) structure, which incorporates strong Brønsted and Lewis acids in a B/L acidity ratio of 3.9. The resulting catalyst showed high yield of EL 63.7, 57.6 and 24.8%, from fructose, glucose, and empty palm fruit bunch (EFB), respectively. By isolating the cellulose from EFB, the yield from cellulose in EFB could be increased to 42.8% with a selectivity of 74.8%. Moreover, the catalyst could be reused up to 3 times with decreased of EL formation; and moreover, 90% of initial activity was regained after regeneration.