Preparation Of Methylfuroate And Furoic Acid By Oxidation Of Furfural With High Loading Cobalt Single Atom Catalyst

Metal-based catalysts with considerable demands have important applications in many fields of chemistry,energy,medicine,food and environment.It has been reported that the catalytic activities of metal-based catalysts are greatly dependant on their particle sizes,which are developed from the block to nanoparticles,sub-nanoparticle and then to single atom levels.Among these kinds of catalysts,metal single atom catalyst has the higher catalytic activites and stabilities,and it is helpful to elucidate the catalytic mechanism.However,many technical challenges have still remained in the preparation of metal single atom catalysts so far,especially metal single atom catalysts with high content(>3.0 wt%)is rarely available in the literature.In order to solve this issue,we have successfully synthesized cobalt single atom catalyst with ultrahigh content(7.68 wt%)by pH-driving and self-assembling approaches following with carbonization.Interestingly,the as-synthesized cobalt single atome catalyst show high activities towards aerobic oxidation of furural conversion into high value-added methylfuroate and furoic acid.The findings will open a new avenue for valorization of biomass hemicellulose in future.The main resutls are as follows:1.To prepare a metal-tannic acid coordination complexes,which is used as precursors of metal single atom catalysts.pH-driving and self-assembling approaches are employed to synthesize a series of transition metals-tannic acid coordination complexes(Co-TA,Zn-TA,Mn-TA,Cu-TA,Ni-TA,Fe-TA,Zr-TA)which precipitate under the optimum pH.2.To synthesize and characterize cobalt single atom catalyst.Cobalt/zinc-tannic acid coordination complexes are used as the precursor to synthesize nitrogen-doped carbon loaded cobalt single atom catalysts(Co SAs-N@C)after carbonization at 900?.The structural properties of the as-prepared catalysts are characterized by XRD,XPS,HR-TEM,HAADF-STEM and cobalt content is calculated to be 7.68 wt%by ICP measurement.3.To convert furfural into high value-added methylfuroate and furoic acid through aerobic oxidation by Co SAs-N-@C.The yield of methylfuroate with 93.2%is obtained using Co SAs-N@C for one-step oxidative esterification of furfural and methanol under the conditions of temperature 60?,pressure 1 bar O2 and reaction time 3 h.The yield of furoic acid with 93.6%is achieved using Co SAs-N-C for aerobic oxidation of furfural under the conditions:temperature 80?,pressure 1 bar O2,reaction time 2 h,and Na2CO3 as catalytic agent.