Synthesis of Renewable Jet Fuel Precursors from C-C Bond Condensation of Furfural and Ethyl Levulinate in Water

Abstract

Biomass derived jet fuel is proven as a potential alternative for the currently used fossil oriented energy. The efficient production of jet fuel precursor with special molecular structure is prerequisite in producing biomass derived jet fuel. We synthesized a new jet fuel precursor containing branched C 15 framework by aldol condensation of furfural (FA) and ethyl levulinate (EL), where the latter of two could be easily produced from lignocellulose by acid cat- alyzed processes. The highest yield of 56% for target jet fuel precursor could be obtained at the optimal reaction con- dition (molar ratio of FA/EL of 2, 323 K, 50 min) by using KOH as catalyst. The chemical structure of C 15 precursor was specified as (3E, 5E)-6-(furan-2-yl)-3-(furan-2-ylmethylene)-4-oxohex-5-enoic acid (F 2 E). For stabilization, this yellowish solid precursor was hydrogenated at low temperature to obtain C=C bonds saturated product, and the chem- ical structure was proposed as 4-oxo-6-(tetrahydrofuran-2-yl)-3-(tetrahydrofuran-2-yl)-methyl hexanoic acid (H-F 2 E). The successful synthesis of the new jet fuel precursors showed the significance that branched jet fuel could be poten- tially produced from biomass derived FA and EL via fewer steps.