The Study On Nano Metal Catalyzed Oxidative Condensation Of Furfural And Molecular Alcohols

At present,along with the large consumption of fossil fuels and the growing environment pollution problem,the efficient ulitizition of renewable biomass resources has aroused scientists' extensive concerns in recent years.As a common biomass derived platform compound,furfural can be employed to produce numerous high value-added chemicals through hydrogenation,oxidation,esterification and reduction amination reactions,and so on.Thus,developing the catalytic conversion of furfural is very significant on the science and industrial applications.In this thesis,using nano metal as catalyst,the oxidative condensation,oxidation esterification and oxidative condensation-hydrogenation of furfural to fine chemicals have been studied in detail.Firstly,the supported nano gold catalysts with different support were prepared by precipitation method,and were further employed as catalysts to promote the oxidation of furfural with methanol and n-propanol.As a result,it is found that the oxidative condensation ocuurs in the “furfural-n-propanol-O₂” system,while the oxidation esterification happens in the “furfural-methanol-O₂” system.For example,the conversion of furfural arrived at 94% and the product selectivity of 2-methyl-3-?2-furyl?acrolein was 97% in n-propanol with O₂ as the oxidant at 140 ? for 4h when Au/FH?Fe_xO_y-HAP?and K₂CO₃ was used as catalysts.In methanol,a 93% conversion of furfural and a 99% selectivity of methyl furoate was obtained under the similar conditions;Then,the recycling test of catalyst was performed and it was found that the product yield was above 90% after being used 5 times,which indicates that the gold catalyst can keep good stability during the reaction.Finally,all the catalysts were respectively characterized by TEM,XRD,BET and TPD techniques.The result can be employed to explain reasonablely the catalytic activity of different Au-based catalysts in the oxidation process.Secondly,the oxidative condensation of furfural and ethanol is studied with the various and heterogenous supported gold catalysts.It was found that the conversion of furfural was 94% and the selectivity of 3-?2-furyl?acrolein was 75% in the presence of molecular oxygen at 140 ? for 4 h when the Au/Al₂O₃ and K₂CO₃ was used as catalyst.In the following,the effects of different additives,different time,different temperature were investigated and a possible reaction mechanism is proposed according to the results of catalytic valuation and reaction phenonema.Finally,the supported nano platinum catalysts were prepared by impregnation method,and were further tested by XRD,BET,TEM,SEM,TPD and UV-vis,and so on.Then,these materials were applied as catalysts for the catalytic oxidation condensationhydrogenation of furfural and molecular alcohol.The results showed that a 93% conversion of furfural and a 67% selectivity of 3-?2-furyl?acrolein was obtained at in ethanol 140 ? for 4h with O₂ as the oxidant usingwith Au/FH and K₂CO₃ as catalyst and additive.In n-propanol,the conversion of furfural was 90%,and the selectivity of 2-methyl-3-?2-furyl?acrolein was90% under the same conditions.Moreover,the reaction mixture was transferred to hydrogenation reactor and was carried out under 5.0 MPa pressure of hydrogen at 220 ?.After 4h,it can be found that the conversion rate of 2-methyl-3-?2-furyl?acrolein was 87%and the selectivity of 2-methyl-3-?2-furan-?propanol was 73%.Furthermore,the catalytic reaction mechniasm is proposed according to the data of control experiment and reaction phenonema.