Solvent-free synthesis of jet fuel by aldol condensation and hydroprocessing of cyclopentanone as biomass-derivates

The conversion of biomass to jet fuel by thermochemical methods has become attractive to achieve the disposal of wastes and the production of highly valued fuels and chemicals. Aldol condensation of cyclopentanone from biomass catalytic fast pyrolysis and hydroprocessing of condensates were performed over Mg–Al–O and Ni/γ-Al2O3 to produce jet fuel under solvent-free conditions. The analysis of the carbon flow revealed that 37 carbon mole (CM) C10 alkane and 28 CM C15 alkane can ultimately be obtained from 100 CM cyclopentanone. Condensation catalyst with the Mg/Al mole ratio of 3:1 performed best due to its higher strength of weak and medium basic sites. Aldol condensation of cyclopentanone was confirmed to be a consecutive reaction that was obviously promoted at higher temperature. With regard to hydroprocessing, the yield of alkanes was greatly increased to 83.79% at 260 °C. Hydroprocessing of dimers and trimers followed very different pathways, and dimeric alcohols and trimeric alkenes played the role of important intermediates respectively. This study advances the development of jet fuel production from sustainable and green sources, providing a theoretical foundation for technology optimization and catalysts design.