FeNi/hexagonal Boron Nitride for Catalytic Hydrodeoxygenation of Guaiacol Derived from Lignin to Cycloalkanes

Catalytic hydrodeoxygenation (HDO) was the essential step for fuel production through the conversion of lignin-derived phenolic compounds to C6-C9 cycloalkane. In this study, Fe-Ni supported on the hexagonal boron nitride (h-BN) catalysts were synthetized and applied in the hydrodeoxygenation of guaiacol derived from lignin to cycloalkanes. The performance of FeNi/h-BN was investigated. The synergistic effect of bimetals can make transition metals show the same catalytic performance as precious metals, among which Fe10Ni1/h-BN (10 %) catalyst had the highest catalytic activity for the generation of cycloalkanes. The conditions of reaction temperature and reaction time were optimized. Guaiacol had high conversion (>98 %) and cycloalkane selectivity (98.4 %) in decalin solvent, because the interaction between Ni and Fe promotes the reduction of metal sites and the adsorption of hydrogen, and the electron transfer of Fe to Ni weakens the CO bond of the substrate intermediate, leading to its cracking and promoting the formation of cycloalkanes. At the same time, cyclohexanol was the main product in the aqueous phase, and the yield of the target product cycloalkanes was low, only 15.9 %. The main reasons were the competition between the oxygen of the oxygenated solvent and the intermediate of the reactant, and the ring opening reaction of cyclohexane in the aqueous phase, which limits the reaction of HDO. According to the change trend of the products under different conditions, the reaction path of guaiacol hydrodeoxygenation to prepare cycloalkane fuel was obtained. Catalyst after cycle test 5 times, maintain a good activity, total hydrocarbon production rate remained at 79.3 %, conversion rate, at 82.6 %.