One-pot Synthesis Of Levulinate And ?-pentyl From Biomass-based Furfural Valerolactone From

Due to the increased concerns about environmental protection and diminishing fossil fuel reserves,the development of utilizing renewable biomass to produce platform chemicals and alternative fuels ha s received widespread attention.Furfural is probably the only unsaturated,industrial available,organic chemical prepared from agricultural wastes,and which is an important biomass platform compounds.Developing new strategy to promote the conversion and utilization of furfural is of great significance for solving energy crisis and environmental problems.Alkyl levulinate and?-valerolactone both are promising and versatile carbohydrate-based product with broad industrial applications.Furfural can directly synthesize alkyl levulinate and?-valerolactone through one-pot process,and the key to the utilization of such reaction is to developing a clean,efficient and process economic cat alytic system.Therefore,a series of innovative studies on one-pot synthesis of alkyl levulinate and?-valerolactone from biomass-based furfural by catalytic transfer hydrogenation were carried out in this paper.Synthesizing catalyst Zr-MCM-41,bifunctional catalyst HPMo/Zr-MCM-41 for the one-pot process of furfural to alkyl levulinate.Synthesizing magnetic catalyst Zr-MCM@Fe₃O₄ for the one-pot process of furfural to?-valerolactone,and further optimize their reaction process.?1?The prepared Zr-MCM-41 and Amberlyst-15 are effective for the directly converting biomass-derived furfural to synthesize the alkyl levulinate without external H₂.The prepared Zr-MCM-41 with a Si/Zr molar ratio of 20 was emerged to provide a catalyst with excellent activity for the transfer hydrogenation of furfural.After introducing Amberlyst-15as a Br?nsted catalyst,an optimized alkyl levulinate yield of 85.3%could be achieved from conversion of furfural using isopropanol as a hydrogen donor at 130? for 24 h.The valid combination of Zr-MCM-41 and Amberlyst-15 was considered as the basis for the high-yield synthesis of isopropyl levulinate.The catalysts could be efficiently separated from the resulting reaction mixture,and the activities of deactivated catalysts were commendably regained by plain regeneration treatment.?2?A bifunctional HPMo/Zr-MCM-41 catalyst which possesses adjustable Lewis and Br?nsted acid sites was prepared for the coupled trans fer hydrogenation and alcoholysis of furfural to yield isopropyl levulinate.The dosage of zirconium and the HPMo species largely influence the catalytic activity of catalyst which for furfural catalytic transfer hydrogenation to furfuryl alcohol and furfuryl alcohol esterification respectively.A high yield of isopropyl levulinate up to 79.6%was obtained by HPMo/Zr-MCM-41 with Si/Zr molar ratio 60 and HPMo impregnation concentration20 g/L at 150 ^oC for 24 h in isopropanol.The spent catalysts reused with increasing deactivation which is ascribed to the carbon deposition on the catalyst surface and loss of Br?nsted acid sites,as clarified by Pyridine adsorbed FT-IR and elemental analyses.The deactivated catalyst can be well recovered by reimpregnation treatment.?3?Finally,Zr-MCM@Fe₃O₄ catalyst was prepared by magnetic method for the directly converting biomass-derived furfural to synthesize the?-valerolactone without external H₂.A series of catalysts were characterized by BET,TEM,XRD,XPS and MPMS,the results showed that the textural properties and surface morphology were affected by the introduction of magnetic properties,but the catalytic performance was not affected.A high yield of?-valerolactone up to 85.7%was obtained by Zr-MCM@Fe₃O₄ with Si/Zr molar ratio 20 at 130 ^oC for 30 h in isopropanol.More importantly,the used catalyst could be readily separated from the reaction mixture by an external magnet,and the activity and magnetic strength of the catalyst have no significant effect within three times of reuse.In this study,three kinds of catalytic strategy,which has the advantages of simple preparation,low cost,high catalyst activity and good reusability,have been developed including Zr-MCM-41+Amberlyst-15 and HPMo/Zr-MCM-41 for the one-pot process of biomass-derived furfural to alkyl levulinate without external H₂,while Zr-MCM@Fe₃O₄ for efficiently catalytic conversion of furfural to?-valerolactone.The results of this study can be laid a solid foundation for the utilization of biomass-based furfural to biomass chemicals.