磁性NiFe_(2)O_(4)负载Ru催化5-羟甲基糠醛选择性氧化合成2,5-呋喃二甲酸

Selective Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over Ru Supported on Magnetic NiFe_(2)O_(4)

采用水热-煅烧法制备了磁性镍铁尖晶石载体NiFe_(2)O_(4),再采用浸渍-还原法在载体上负载Ru纳米粒子制备Ru/NiFe_(2)O_(4)催化剂。采用X射线衍射(XRD)、N2吸附-脱附(BET)、NH3程序升温脱附(NH3-TPD)、H_(2)程序升温还原(H_(2)-TPR)、X射线光电子能谱(XPS)和电感耦合等离子体发射光谱(ICP-OES)测试对催化剂进行表征分析。结果表明,Ru/NiFe_(2)O_(4)催化剂表面氧物种丰富,相较于载体,负载Ru后催化剂比表面积和表面酸量增加,Ru与载体存在相互作用,这可能是催化剂高活性和高稳定性的关键。将催化剂用于5-羟甲基糠醛(HMF)的选择性氧化,负载Ru后,催化剂催化活性显著提升。对反应条件进行优化,在添加0.08 g KHCO3,氧化剂O2压力为1 MPa,反应温度为80℃,使用0.1 g Ru/NiFe_(2)O_(4)催化剂,在水溶液中反应12 h HMF能完全转化,2,5-呋喃二甲酸(FDCA)产率为98.1%。Ru/NiFe_(2)O_(4)循环使用5次后仍能保持较高的活性,催化剂上活性组分Ru不易浸出,并且催化剂具有磁性能便于与反应溶液分离。为今后工业化催化HMF高效选择性氧化合成FDCA提供参考。

The magnetic nickel-iron spinel carrier NiFe_(2)O_(4)is prepared by hydrothermal calcination,and then Ru/NiFe_(2)O_(4)is prepared by impregnation reduction method by loading Ru nanoparticles on the carriers.The catalyst is characterized by X-ray diffraction(XRD),N2 adsorption-desorption(BET),NH3 programmed temperature desorption(NH3-TPD),H_(2)programmed temperature reduction(H_(2)-TPR),X-ray photoelectron spectroscopy(XPS)and inductively coupled plasma optical-emission spectrometry(ICP-OES).The results show that the surface oxygen species of Ru/NiFe_(2)O_(4)catalyst are abundant,and compared with the carriers,the specific surface area and acid amount of the catalyst increases after loading Ru,and Ru interacts with the support,which may be the key to the high activity and stability of the catalyst.The catalyst is used for the selective oxidation of 5-hydroxymethylfurfural(HMF),and the experimental results show that the catalytic activity of the catalyst is significantly increased after loading Ru.The reaction conditions are optimized,when 0.08 g of KHCO3 is added,the oxidant O2 pressure is 1 MPa,the reaction temperature is 80℃,and 0.1 g of Ru/NiFe_(2)O_(4)catalyst is used,HMF could be completely converted in water solution for 12 h,and the yield of 2,5-furandicarboxylic acid(FDCA)is 98.1%.Ru/NiFe_(2)O_(4)can still maintain high activity after 5 cycles,and the active component Ru on the catalyst is not easy to leach.The catalyst has magnetic performance,which is convenient for separation from the reaction solution.The research provides valuable reference for the future industrialization of the highly efficient selective oxidation of HMF to synthesize FDCA.