| High-density liquid fuel composed of cyclic hydrocarbons can provide higher density and more volumetric energy,and is particularly important for volume-limited aircraft.The production of high-density fuel from biomass is a promising route toward a decrease in petroleum dependence and the mitigation of environmental issues.In this work,we explored the C-C coupling reaction of petroleum and lignocellulose derivatives,and subsequent hydrodeoxygenation reaction,and synthesized traditional high density fuel and biomass-based dicyclic fuel,1,3-branched monocyclic fuel,1,1-branched monocyclic fuel.Catalytic isomerization and Diels-Alder addition reaction of endo-dicyclopentadiene for petroleum-based high-density fuel has been investigated.Microporous zeolite shows low activity due to the mass transfer limitation.XRD,TEM and N2 adsorption/desorption confirm that moderate alkali treatment removes the amorphous phase and produces mesopores,but the framework collapses under rigorous conditions.NH3-TPD and pyridine adsorption IR indicate that the presence of mesopores increases the accessibility of acid sites in microchannles,especially for large molecules.The hierarchical ZSM-5 shows higher activity and selectivity in the isomerization and oligomerization reaction than microporous zeolite.Aldol self-condensation reaction of cyclic ketones like cyclopentanone and cyclohexanone for dicyclic biofuel has been studied.The traditional acid and base catalysts show low selectivity of the mono-condensed product,and the di-condensed byproducts generate quickly.MOF(MIL-101,MIL-100)encapsulating phosphotungstic acid(PTA)was synthesized,and XRD,TEM,ICP,31 P NMR and N2 adsorption/desorption and acid-base titration confirm PTA clusters are uniformly dispersed in MOF cages,also show that with the increase of PTA,the acidic sites will be more,the empty space will decrese.PTA@MOF improves the selectivity of mono-condensed product and suppresses the generation of di-condensed product via the shape selectivity.After hydrodeoxygenation of the mono-condensed product,dicyclic biofuels with density of 0.867-0.887 g/cm3 were obtained.Aldol condensation reaction of cyclic ketone with furfural/5-hydroxymethylfurfural for 1,3-branched monocyclic biofuel has been inverstigated.Under the solvent-free conditions,the reaction shows high conversion and selectivity at 30 °C with high dosage of Na OH or at high temperature with low dosage of Na OH,reaction can get very good activity.The reaction rate slows down when the reactant is changed from cyclopentanone to cyclohexanone or from furfural to 5-hydroxymethylfurfural.After hydrodeoxygenation,1,3-branched chain monocyclic biofuels with density of 0.815-0.826 g/cm3 were obtained.Hydroxyalkylation/alkylation of cyclohexanone with 2-methylfuran to synthesize monocyclic biofuel has been investigated.Compared with cyclopentanone,because cyclohexanone is a better electrophile,the reaction of cyclohexanone is faster and the side reaction is suppressed under nafion-212.Meanwhile,under the presence of polar solvent and amberlyst-15,the hydroxyalkylation intermediate was synthesized selectively.After hydrodeoxygenation,monocyclic biofuels with density of 0.804-0.825 g/cm3 were obtained.Hydroxyalkylation/alkylation reaction of cyclopentanone with 2-methylfuran to synthesize 1,1-branched chain monocyclic biofuels using hydrophobic-oleophilic acid resin as catalyst has been explored.Hydrophobic-oleophilic sulfonic acid functional resin(PS)and fluoride sulfonic acid functional resin(PCS)were synthesized.ICP,N2 adsorption/desorption,acid-base titration and contact angle characterizations confirm hydrophilic monomer decreases surface area,provides active sites and diminishes the hydrophobicity-oleophilicity.PS and PCS show more active and selective than amberlyst-15 and nafion-212,because of larger surface area,better mesoporous structure and hydrophobicity-oleophilicity.After hydrodeoxygenation,1,1-branched chain monocyclic biofuels with density of 0.819-0.825 g/cm3 were obtained. |
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