5-05: Aqueous phase depolymerization and hydrodeoxygenation of lignin to jet fuel

A key challenge in using lignin as a biofuel resource is its intrinsic complex crosslinked polymeric structure. A novel aqueous catalytic processing of depolymerized lignin into low molecular weight oligomers then to cyclohexanol/cyclohexanone further to alkanes through a series of hydrotreating reactions will be presented in the study. The lignin polymer from biomass is deploymerized via hydrothermal pretreatment with or without additives followed by selective hydrolysis of the C-O-C bond. The reactive intermediates generated could be further hydrogenated to destroy the aromaticity of phenyl rings and concomitantly undergo hydrodeoxygenation of the C-O bonds, thereby transforming lignin to C₉ and C₁₄–C₁₈ alkanes and methanol.

Overall, this presentation include: 1) selectively produce soluble lignin oligomers from lignocellulosic biomass and understand the reaction chemistry of delignification of lignocellulosic biomass; 2) design catalysts that convert soluble lignin to hydrocarbons (cyclohexanol/cyclohexanone and/or alkanes) with high yield; 3) improve understanding of lignin chemical properties, such as solubility, molecular weight, and monolignol composition in the deploymerization reactions that lead to hydrocarbons from HDO process with high yield. Importantly, the reaction chemistry and kinetics of lignin depolymerization and hydrodeoxygenation will be also addressed.