Photosensitized Conia reaction directed synthesis of high-performance asymmetric polycyclic hydrocarbons from biomass-derived ketones and petroleum-derived norbornene

Solar-energy-driven synthesis of high-density biofuels can help to achieve the dual carbon goal of the aviation industry sooner. Herein, a novel photo-Conia strategy was developed for synthesis of high-performance asymmetric polycyclic hydrocarbons from biomass-derived various ketones and petroleum-derived norbornene. The photosensitized Conia reaction mechanism is comprehensively revealed by the combination of monochromatic light excitation, triplet quenching, phosphorescence quenching, Stern-Volmer kinetic analysis and DFT calculations. The photoaddition of cyclopentanone and norbornene has a much faster reaction rate than self-cycloaddition of norbornene, and the green solvent water can promote both the norbornene conversion and the selectivity of monoadduct, along with the optimal norbornene conversion of 94.9 % and monoadduct selectivity of 91.6 %. After hydrodeoxygenation, the hydrocarbon derived from cyclohexanone/norbornene mixture endows high density of 0.941 g∙mL⁻¹ (20.6 % higher than conventional aviation kerosene, 0.78 g∙mL⁻¹) and volumetric net heat of combustion of 40.11 MJ∙L⁻¹, which is much higher than that of classic JP-10 (39.41 MJ∙L⁻¹). Therefore, this work provides a new and eco-friendly route for synthesis of high-performance hydrocarbons using renewable resources (biomass) and renewable energy (solar energy).