Yaping Liu,Chao Pan,Xianjie Li,Hailin Zhang,Zhijie Shang,Hongbing Song
Oxidation, a pivotal process in organic synthesis, is essential for the conversion of various biomass derivatives, including 5-hydroxymethylfurfural (HMF), into valuable chemicals. This research employs poly(ionic liquid)s (PILs) as supports to fabricate Au/PILs catalysts, which are subsequently utilized in the oxidative esterification of HMF to produce dimethyl 2,5-furandicarboxylate (FDMC). The modification of PILs demonstrates that catalyst’s performance is optimized when the PILs anion (IL: EGDMA = 1: 4) is [Tf 2 N - ]. The presence of the [Tf 2 N - ] group is essential for charge transfer between the carrier and the active metal Au, thereby enhancing the catalytic reaction. Thermogravimetric analysis (TG) reveals the exceptional thermal stability of the 2 % Au/PILs-Tf 2 N-14 catalyst. The efficient conversion of HMF to FDMC is achieved using the 2 % Au/PILs-Tf 2 N-14 catalyst at 120°C, 12 h, with CH 3 ONa (0.75 equiv.) and 2 MPa O 2 , yielding a HMF conversion ( C HMF ) of 96.41 % and a FDMC selectivity ( S FDMC ) of 100 %. The heterogeneous catalyst 2 % Au/PILs-Tf 2 N-14 maintains high catalytic activity after multiple cycling experiments. A catalyst based on precious metal-loaded PILs was utilized to achieve efficient and selective conversion of HMF to FDMC under low loading conditions. This approach not only offers valuable insights for future research but also promotes the shift towards renewable energy sources. Additionally, the adsorption behavior of O 2 on Au 8 clusters and the interaction between the reaction substrate HMF and [Tf 2 N - ] were examined through density functional theory (DFT) calculations, providing theoretical backing for further investigation.
Linhao Yu,Hong Chen,Yingying Li,Zhe Wen,Yongdan Li
The metallic cobalt supported on nitrogen dopped carbon material was employed as an efficient catalyst in the oxidative esterification of 5-hydroxymethylfurfural (HMF) to furan-2,5-dimethylcarboxylate (FDMC). The carbonization temperature has a significant effect on the morphology and structure of Co/N-C samples. The Co/N-C calcined at 900 °C exhibits the best catalytic performance and a 73.8% FDMC yield at 91.7% HMF conversion is measured at 130 °C for 20 h with K 2 CO 3 under 1 MPa O 2 . The catalytic activity of Co/N-C was benefited by the synergistic effect between the metallic cobalt and nitrogen-doped carbon material. The reaction mechanism of FDMC formation was proposed.
Graphical No base needed : N-doped carbon-supported CoCu bimetallic catalyst with enhanced O 2 activation ability and basicity is demonstrated as an effective catalyst for the oxidative esterification of 5-hydroxymethylfurfural. The introduction of Cu significantly enhances the catalytic activity, resulting in a high furan-2,5-dimethylcarboxylate yield and an impressive formation rate, paving the way for the efficient and green synthesis of sustainable bio-based polymer monomers. The direct fabrication of furan-2,5-dimethylcarboxylate (FDMC), a promising renewable monomer, from biomass-derived 5-hydroxymethylfurfural (HMF) is a cutting-edge process. In this contribution, an elaborately designed N-doped carbon-supported CoCu bimetallic catalyst (Co x Cu y -NC; x / y= 9:1, 7:3, 4:6, which represents the designed molar ratio of Co and Cu in the catalyst), which could offer a desirable FDMC yield of 95 % under mild and base-free conditions (Co 7 Cu 3 -NC, 2 bar O 2 , 80 °C, 4 h) is described for the oxidative esterification of HMF. Notably, an FDMC formation rate of 6.1 mol FDMC mol Co −1 h −1 was achieved over Co 7 Cu 3 -NC, which represents the highest catalytic efficiency so far among Co-based catalytic systems. It has been demonstrated that Cu-doping in Co 7 Cu 3 -NC catalyst brings about more active sites (Co-N x species) with stronger molecular oxygen activation ability. The increase of surface N content of Co 7 Cu 3 -NC also improves basicity of the catalyst, which favors the hydrogen abstraction process during the HMF oxidative esterification reaction. These findings may pave an efficient and green way for the synthesis of sustainable bio-based polymer monomers.