Efficient conversion of furfuryl alcohol to ethyl levulinate with sulfonic acid-functionalized MIL-101(Cr)

Catalytic ethanolysis of furfuryl alcohol (FA) to ethyl levulinate (EL) with MIL-101(Cr)–SO3H, prepared by simple one-pot hydrothermal treatment, is presented for the first time. The as-prepared catalyst with high surface area, hydrothermal and chemical stability, good dispersion, and feasible accessibility of –SO3H Brønsted acid sites was found to show superior performance to other sulfonic acid-functionalized solid catalysts. Besides the special textural properties, the obtained good catalytic activity of 79.2% EL yield and 100% FA conversion were also dependent on the density and strength of the Brønsted acid and the reaction parameters. A slight loss of catalytic activity after five consecutive recycles and the hot filtration experiment confirmed the good stability of MIL-101(Cr)–SO3H. Two coexisting reaction paths for the ethanolysis of FA to EL catalyzed by MIL-101(Cr)–SO3H were proposed, wherein 2-ethoxymethylfuran (2-EMF) was observed to be the dominant intermediate.