Synthesis of sustainable aviation biofuels via catalytic hydropyrolysis of lignin

Abstract

The exploitation of bimetallic catalysts to lignin for sustainable aviation biofuels remains a daunting challenge due to the low selectivity of aviation biofuel-range hydrocarbons and inconsistent reaction mechanism. Herein, bimetallic supported on SiO2 catalysts were prepared and their hydrodeoxygenation reactivity during lignin catalytic hydropyrolysis was explored. Approximately 100 % selectivity toward aviation-range hydrocarbons were achieved using eugenol as model compound under relatively mild conditions with the presence of NiMo/SiO2. For lignin catalytic hydropyrolysis, the yield of liquid hydrocarbons and the selectivity of aviation-range hydrocarbons was 21.99 wt% and 70.50 %, respectively. High mass balance (89.66 %) was verified by scale-up experiments in a continuous flow high-pressure reactor system. The reactivity of demethoxylation reaction, dehydroxylation reaction, and benzene ring hydrogenation reaction with the presence of bimetallic catalysts were analyzed. The density functional theory calculation and verification experiments revealed the evolution pathway of aromatic hydrocarbons and cycloalkanes from lignin catalytic hydropyrolysis. The proposed reaction mechanism can provide guidance for the regulation of aviation biofuel components from lignin catalytic hydropyrolysis.