Synthesis Of High-density Aviation Fuel From Biomass Derivativies

Energy is an important resource for the development of human society.Due to the problems of non-renewability and environmental pollution of fossil fuels,the development of new renewable green energy has become a common goal around the world.Aviation fuel is an important fuel that is widely used,and its usage is increasing year by year with the development of military and civil aviation.Biomass energy has the advantages of being renewable,widely sourced and cheap,and has attracted a large number of domestic and foreign scholars to study it in recent years.Lignocellulose is a major part of biomass energy.Using lignocellulose as raw material to prepare aviation fuel can effectively alleviate the shortcomings caused by the use of fossil fuels.This paper mainly studies the synthesis route of C13 cycloalkanes through aldol condensation reaction and hydrodeoxygenation reaction using lignocellulose platform compounds vanillin and cyclohexanone as raw materials,including the following aspects:Synthesis of high-density aviation fuels from vanillin and cyclohexanone.Vanillin and cyclohexanone undergo aldol condensation reaction through solid acid catalysts.A series of titania-based nanomaterials were prepared by hydrothermal method,among which sulfated titania nanofibers（STNF）showed the best catalytic activity.And no evident deactivation was observed during the five repeated usage.By optimizing the reaction conditions,the catalysts were screen and the yield of fuel precursor（E）-2-（4-hydroxy-3-methoxybenzylidene）cyclohexan-1-one was improved.The results showed that the yield of precursor from vanillin and cyclohexanone reached 81.44%with 0.05 g STNF catalyst,vanillin and cyclohexanone molar ratio at 1:3 under 150℃for 10 hours.NH₃-temperature-programmed desorption,solid state NMR and Py-IR were performed on solid acid catalysts to determine their acid properties.The results showed that the STNF exhibited the highest acid strength and the highest Br（?）nsted acid sites to Lewis acid sites ratios,indicating that the acid strength of the catalyst was the most important factor affecting the catalytic activity of this reaction.The obtained oxygen-containing aviation fuel precursors were subjected to hydrodeoxygenation reaction in an autoclave.Through the screening of catalysts,the condensation product of vanillin and cyclohexanone,using 0.1 g Pd/C and 1.3 g HY zeolite as co-catalysts,were reacted at 200°C and 6 MPa hydrogen for 4 hours,and the yield of naphthenic mixture（0.95 g/m L）reached 91.13%.The presence of methoxy makes hydrodeoxygenation more difficult.When Pd/C used as a catalyst alone,it is difficult for the precursor to remove the methoxy group.After adding HY,the methoxy group becomes easy to remove as the acidity in the reaction system increases.Sythesis of high-density aviation fuel rome benzaldehyde and 2-cyclopentylcyclopentanone.Using cyclopentanone as raw material,2-cyclopentylcyclopentanone was prepared by Na OH catalyzed aldol condensation of cyclopentanone,followed by Pd/C catalyzed hydrogenation.Then Benzaldehyde and 2-cyclopentylcyclopentanone undergo aldol condensation reaction through solid base catalysts.Solid bases supported by Al₂O₃ were prepared by impregnation method,among which K₂CO₃/Al₂O₃ showed the best activity.The yield of precursor（Z）-3-benzylidene-[1,1’-bi（cyclopentan）]-2-one from benzaldehyde and 2-cyclopentylcyclopentanone reached 85.75%with 0.2 g K₂CO₃/Al₂O₃ catalyst under 160℃for10h.After hydrodeoxygenation,the yield of the high-density fuel 3-cyclopentyldodecahydrocyclopenta[a]indene（0.98 g/m L）reached 98.3%over 0.1 g Ru/C catalyst under 180°C and 4 MPa hydrogen for 4 hours.