Studies On Selective Activation Of C-C And C-O Bands Of Cellulose And Its Derivative For Production Of Ethanol And Adipic Acid

The efficient use of abundant renewable biomass to prepare chemicals and fuels is full of great significance to solve energy and environmental problems.Cellulose as one of the most abundant part in lignocellulose contains the high oxygen content.It is atom economical for the selective conversion of cellulose into high-value-added oxygen-containing chemicals.This paper mainly focused on the conversion of cellulose into ethanol and its derivative for production of adipic acid,the main results were as follows:1.We developed zirconia-supported Pt-nanoparticles(Pt/ZrO2)combined with H2WO4 as catalyst to realize the conversion of cellulose into ethanol,through the activation and cleavage of specific C-C and C-O bonds under 523 K,hydrogen atmosphere.The yield of ethanol was 32%.The study showed that cellulose hydrolysed to glucose,then undergone the C-C bond cleavage through retro-aldol fragmentation to prepara C2 product.Finally,C2 product converted to ethanol by hydrogenation and hydrogenolysis.H2WO4 played the important role in the C-C bond cleavage,especially the C2-C3 bond in glucose unit and as the protonic acid catalyzing hydrolysis of cellulose.Pt/ZrO2 catalyzed the hydrogenation of C=O bond and the hydrogenolysis of C-OH bond in C2 intermediates into ethanol.A Pt nanoparticles with proper fraction of Pt0 and Pt2+on ZrO2 are crucial to adjusted ethanol selectivity to suppress the over-hydrogeno1ysis.Pt0 functioned as an active site for hydrogenation or hydrogenolysis,while Pt2+ promoted the dispersion of Pt0 and promoted the production of ethanol by suppressing overhydrogenolysis.2.We focused on the preparation of adipic acid by using heterogeneous Re catalyst to achieve selective activation of C-OH bond of cellulose derivative glucaric acid through dehydroxylation.By investigating the performance of various metal components with dehydroxy active like V,Mo and Re,we found that Re-Pd/AC catalyst has excellent deoxydehydration(DODH)reactivity of catalyzing the conversion of D-Saccharic acid potassium salt to adipic acid with the yield of 91%in methanol,383 K,P(H2)=2 MPa,24 h.Through the characterization of catalyst,it was found that the initial state of the catalyst with more Re6+ has high reactivity,and Re species may undergo redox process between Re6+and Re4+ in the reaction.Pd in catalyst may mainly catalyze hydrogenation reaction.