催化转化5-羟甲基糠醛（HMF）制备呋喃衍生物

With the continuous consumption of fossil resources, it is of great importance to exploit and utilize renewable biomass resources for preparation of bulk and fine chemicals. 5-Hydroxymethylfurfural (HMF), which can be obtained from dehydration of glucose or fructose under the catalyzing of acid, is a compelling platform chemical for the production of 2,5-diformylfuran (DFF), 2,5-bishydroxymethylfuran (BHMF), 5-hydroxymethyl-2-furancarboxylic acid (HFCA) and 2,5-furandicarboxylic acid (FDCA). These stuffs have been regarded as promising monomers for preparing resins, polymers and fine chemicals. The development of highly efficient, environmental-friendly catalytic system for the preparation of furan-based materials from HMF is a key research field nowadays. Porous Bi-doped ceria was prepared by the citrate method, and there existed large amount of oxygen vacancies in the obtained Ce1?xBixO2?δ solid solution. In the presence of O2, Ce1?xBixO2?δ (0.08 ≤ x ≤ 0.5) efficiently catalyzed the conversion of HMF to HFCA and BHMF in alkaline aqueous solution without degradation of HMF. A 97% conversion of HMF was achieved only after 20 min. The excellent catalytic activity was attributed to the oxygen activation and hydride transfer enhanced by Bi doping and the large amount of oxygen vacancies. After Au nanoparticles (NPs) were supported on Ce1?xBixO2?δ (x ≤ 0.2), the presence of Auδ+ facilitated the activation of the C-H bond in the hydroxymethyl group and then the production of FDCA as an end product, inhibiting the generation of BHMF. When performing the reaction at 65 °C, a >99% yield of FDCA was obtained after 2 h over the Au/Ce0.9Bi0.1O2?δ catalyst. The oxidation of HMF to FDCA was efficiently catalyzed when PVP stabilized Pt NPs were supported onto a Ce0.8Bi0.2O2?δ solid solution. 98% yield of FDCA was achieved within 30 min at room temperature and the catalyst was reused five times without much loss of FDCA selectivity. It is the first report on the oxidation of HMF, an alcohol and an aldehyde, effectively catalyzed by a ceria-based material supported Pt catalyst. The individual properties of the Pt NPs and the ceria-based support were retained and not affected after their combination. The superior oxygen activation ability of the Bi-doped ceria thoroughly changed the performance of the ceria supported Pt catalyst. The specific functions of Pt NPs and Bi-containing ceria were well incorporated during the catalytic oxidation cycle, leading to the generation of the highly efficient Pt/Ce0.8Bi0.2O2?δ catalyst for the oxidation of alcohol group and aldehyde group at room temperature. A series of Bi-contained oxide supported Pt catalyst were prepared and was evaluated for the selective oxidation of HMF to FDCA. All the catalysts showed excellent catalytic activities. When using Pt/Bi2W3O12 catalyst, a 100% conversion of HMF and a 99% yield of FDCA were obtained only after 15 min at room temperature. The effect of the reaction parameters on the product distribution was also investigated, such as amount of base, oxygen pressure, temperature and the usage amount of catalyst. When performing the reaction at high temperature and high oxygen pressure, the prepared Au/LaMO3 (M = Cr, Mn, Fe, Co, Ni) could catalyze the oxidation of HMF to HFCA and FDCA. When it reaction at room temperature and air atmosphere, the Au/LaMnO3 efficiently catalyzed the Cannizzarro reaction of HMF, and the catalytic activity was highly enhanced after doping 10mol% Zn in the Au/LaMnO3. With the presence of Au/LaMn0.9Zn0.1O3, HMF was totally converted only after reaction for 5 min, the Cannizzarro reaction products BHMF and HFCA were obtained equally. Liquid-phase selective oxidation of cyclohexane is a very important reaction in the industry. The effect of the treatment conditions on the catalytic activity towards cyclohexane oxidation was investigated using the model catalyst, SiO2@Au. The hydrophobic treatment reduced the catalytic