1 research outputs found
Catalytic Transfer Hydrogenation and Ethanolysis of Furfural to Ethyl Levulinate Using Sulfonated Hf- or Ni-Catalysts Prepared with Mixed Solvents
Bifunctional Lewis (L) acid (Ni- or Hf-) site–Brønsted
(B) acid catalysts designed to promote transfer hydrogenation reactions
were prepared via hydrothermal and solvothermal methods using safe
mixed solvents and sustainable precursors. By using N,N-dimethylformamide as a basis for the desired
basicity, mixed solvents could be identified that allowed catalysts
to be prepared with tunable ratios of Lewis to Brønsted acid
sites (L/B). The as-prepared catalysts promoted transfer hydrogenation
of furfural and ethanolysis to form ethyl levulinate (EL) using ethanol
as a solvent and hydrogen donor source. Among the catalysts, sulfonated
Hf-catalysts prepared with a cyclopentanone/formic acid mixed solvent
(Hf-CPN/FA) with an L/B ratio of 6.4 gave 95% furfural conversion
with 51.9% yield of EL, while the sulfonated Hf catalyst prepared
with a cyclopentanone/γ-valerolactone mixed solvent (Hf-CPN/GVL)
with a total Lewis and Brønsted acid site amount of 85.1 μmol/g
gave 100% furfuryl alcohol (FAL) conversion with 72.5% yield of EL.
Brønsted acid sites promoted reversible acetalization of furfural
with ethanol into 2-furaldehyde diethyl acetal, while Lewis acid sites
promoted furfural transfer hydrogenation into FAL and EL and further
conversion into γ-valerolactone. The methods developed in this
work eliminate dipolar aprotic solvents and harsh acids used in catalyst
synthesis and allow sustainable production of EL from biomass-related
chemicals