Synthesis Of High-quality Fuel From Biomass-derived Furfural And Cyclopentanone

Diesel and jet fuel,as the two types of fuels in greatest demand,currently are mainly produced from petroleum refinery.However,due to the limited reserve of fossil energy and wide concern of environmental problems,the substitutes of fossil fuels with renewable energy is of crucial importance.Lignocellulose is the cheapest and most abundant nonedible biomass.Meanwhile,it is also the main component of agriculture waste and forest residue.It is an ideal feedstock for the production of renewable fuels and chemicals because it avoids the using of foods and arable land.In this work,high-quality diesel or jet fuel range alkanes were synthesized by the aldol condensation of furfural and cyclopentanone which can be obtained from lignocellulose,followed by the hydrodeoxygenation of aldol condensation products.The content of this work is mainly composed as follows:A series of solid base catalysts were prepared by incipient wetness impregnation,co-precipitation and sol-gel methods firstly,and then tested in the aldol condensation of furfural with cyclopentanone under the same conditions.The obtained products and unreacted furfural were analyzed by high performance liquid chromatograph and nuclear magnetic resonance.It is found that the main product was C₁₅ fuel precursor,2,5-bis?2-furylmethylidene?cyclopentan-1-one?F₂C?,and KF/g-Al₂O₃ exhibited the best performance among the investigated catalysts.The catalysts were characterized by X-ray diffraction?XRD?,N₂-physical adsorption,CO₂-temperature programmed desorption and CO₂-pulse adsorption.It is suggested that KF/g-Al₂O₃ has very strong base strength which is the main factor affecting the catalytical activity.The strong base sites on the catalyst surface originate from the interaction of KF and Al₂O₃ during the preparation process.In addition,the reaction conditions were optimized and the KF loading of KF/g-Al₂O₃ is verified to be the main factor.100%of furfural conversion and 95%of F₂C yield can be obtained over 33 wt.%KF/g-Al₂O₃ at 60°C within 2 h.The hydrodeoxygenation of F₂C was investigated starting with the low-temperature prehydrogenation over commercial Pd/C.Then the followed hydrodeoxygenation of the prehydrogenation products was conducted over different Pt-based catalysts.The products distribution was analyzed by gas chromatograph-mass spectrometer and the catalysts were characterized by XRD and NH₃-adsorption/desorption.It is suggested that acid sites on the support play an important role on the hydrodeoxygenation reaction and can promote the C-O bond breaking.Thus,ZrP is a good support for hydrodeoxygenation because of its suitable acidity.Considering the high cost of noble metal,other ZrP-supported metal catalysts were also investigated in the hydrodeoxygenation reaction.It is found that the yield of diesel or jet fuel range alkanes obtained over Cu/ZrP was similar with that obtained over noble-metal catalysts.Cu/ZrP even has higher deoxygenation efficiency,noticing that complete hydrodeoxygenation can be achieved at 280°C with it.Under the optimized reaction condition,94%yield of diesel or jet fuel range alkanes can be obtained over Cu/ZrP,of which 79%is C₁₅ cycloalkanes.