Catalytic hydrodeoxygenation of furylmethane oxygenates to high carbon branched chain jet and diesel fuel range alkanes under mild reaction conditions is a challenging strategy for energy efficient production of fuels with minimal loss of renewable carbons via C−C cracking process. Here, we report that a strong Lewis acidic promoter can overcome the energy barrier for furylmethane hydrodeoxygenation by promoting a facile ring-opening step of furans. Furan rings of furylmethanes are first hydrogenated to fully saturated cyclic ethers by a strong hydrogenation catalyst like carbon supported palladium. Furan based cyclic ethers then then undergo facile Cb-H atom transfer based ring opening and subsequent deoxygenation from primary alcoholic intermediate oxygenates. Formation of a cyclic intermediate prior ring-opening via C-O bond activation was suggested as a result of interaction between ethereal O and the Lewis acidic metal center Hf, assisted by the triflate ligand of the promoter. Probing the reaction pathway with symmetric single furan ring surrogate molecules suggests that the promoter is necessary for the ring opening. Deoxygenation of ring-opened oxygenates takes place more quickly for single furan ring surrogates than for the multiple furan ring furylmethanes. A maximum 97% jet fuel range alkanes with 93% selectivity in C15H32 and C14H30 is achieved from C15-furylmethane under optimal conditions. The yield and selectivity of alkanes with desired carbon numbers can be tuned using furylmethanes with tailored carbon chains, furan numbers, and branching unit that minimizes C−C cracking side reactions.

Hydrodeoxygenation reaction network of furylmethane oxygenates to jet and diesel range fuels: Probing the role of supported palladium catalyst and hafnium triflet promoter

255th National Meeting (2018)

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