Catalytic Hydrodeoxygenation of High Carbon Furylmethanes to Renewable Jet-fuel Ranged Alkanes over a Rhenium-Modified Iridium Catalyst

Renewable jet-fuel-range alkanes are synthesized by hydro-deoxygenation of lignocellulose-derived high-carbon furylmethanes over ReOx-modified Ir/SiO2 catalysts under mild reaction conditions. Ir-ReOx/SiO2 with a Re/Ir molar ratio of 2:1 exhibits the best performance, achieving a combined alkanes yield of 82-99% from C-12-C-15 furylmethanes. The catalyst can be regenerated in three consecutive cycles with only about 12% loss in the combined alkanes yield. Mechanistically, the furan moieties of furylmethanes undergo simultaneous ring saturation and ring opening to form a mixture of complex oxygenates consisting of saturated furan rings, mono-keto groups, and mono-hydroxy groups. Then, these oxygenates undergo a cascade of hydrogenolysis reactions to alkanes. The high activity of Ir-ReOx/SiO2 arises from a synergy between Ir and ReOx, whereby the acidic sites of partially reduced ReOx activate the C-O bonds of the saturated furans and alcoholic groups while the Ir sites are responsible for hydrogenation with H-2.