Efficient conversion of HMF to FDMC utilizing gold-based poly(ionic liquid)s with bis(trifluoromethylsulfonyl)imide anion

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.