| Today, fossil fuels such as coal, oil, and natural gas provide more than three quarters of the worlds energy. Rapid depletion of fossil fuels and escalating energy consumption coupled with rising environmental awareness among nations have led to increased focus on viable, eco-friendly and renewable energy sources.Abundant biomass can serve as a source both energy and carbon, and being renewable for the sustainable production of chemicals and liquid fuels for our industrial society.Moreover, production of energy from biomass has the potential to generate lower greenhouse gas emissions compared to the combustion of fossil fuels. 5-Hydroxymethyl-furfural (HMF) is a promising platform compound produced from the dehydration of carbohydrates, such as cellulose, glucose and fructose. It can be used as a versatile precursor for the production of fine chemicals, plastics, pharmaceuticals and liquid fuels. Selective oxidation of HMF is one of the most pivotal transformations in a biorefinery. The oxidation of HMF can generate several kinds of oxidation products such as 5-hydroxymethyl-2-furancarboxylic acid (HMFCA),5-formyl-2-furancarboxylic acid (FFCA),2,5-furandicarboxylic acid (FDCA) and 2,5-diformylfuran (DFF). DFF as an important oxidative product of HMF, has received significant attention in recent years. It can be used as a versatile precursor for the synthesis of furanic polymers, various poly-Schiff bases, pharmaceuticals, antifungal agents, nematocides, organic conductors, cross-linking agents. It not only can greatly promote the effective utilization of biomass resources, but also has very important significance to alleviate the energy crisis and environmental pollution.Herein, In this thesis, we mainly do some work about the catalytic dehydration of fructose to HMF and aerobic selective oxidation of HMF to DFF.1. A series of TPA/Nb2O5 catalysts prepared by hydrothermal method and the catalysts prepared were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), NH3-temperature-programmed desorption (TPD), and scanning electron microscopy (SEM) techniques. The catalytic dehydration of fructose to HMF in dimethylsulfoxide (DMSO) was performed over the catalysts. The effects of reaction parameters such as catalyst loading amount, ratio of fructose to catalyst, reaction time and temperature on the conversion of fructose were studied. The results suggest that the catalyst 25wt%TPA/Nb2Os exhibited highest activity.0.15 g catalyst shows a maximum HMF yield of 91.6% in DMSO at 120 ℃ after 2 h.2. Using oxygen and TEMPO selective oxidation of alcohols to aldehydes is a green method and plays an important role, we have investigated the oxidation of HMF to DFF using different transition metal nitrates, TEMPO radicals and NaCl as catalyst, and different reaction conditions.Research shows oxidation of HMF with Fe (NO3)3·9H2O/NaCl/TEMPO catalyst system in MeCN for 8 h showed a high selectivity to DFF 96.6% at conversions 99%. In addition, we propose a possible mechanism of this reaction.3. Three different Nb2O5 photocatalysts was prepared by calcination of niohic acid hydrate at different temperatures in the air. Catalytic oxidation of HMF into DFF under visible light with Nb2O5 catalysts. At the same time, we investigated the effect of the catalytic reaction with different Nb2Osmorphologies, different illumination light wavelength and different reaction times respectively. Studies have shown, m800-Nb2O5 catalyst in benzotrifluoride solvent, and with visible light for 6 h, the optimal results can be obtained is 90.6% DFF selectivity and 19.2% HMF conversion. In addition, we also discussed the possible mechanism of this reaction. |
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