Weerathunga Helapiyumi, Sarina Sarina, Zhu Huai-Yong, Waclawik Eric R
School of Chemistry and Physics, Queensland University of Technology, Brisbane, Queensland 4000, Australia.
ACS Omega. 2021 Feb 10;6(7):4740-4748. doi: 10.1021/acsomega.0c05541. eCollection 2021 Feb 23.
Gold nanoparticles (Au NPs) supported on a nanostructured gamma alumina (γ-AlO) fiber can exhibit excellent catalytic activity for the conversion of 5-hydroxymethylfurfural to produce its ester derivative, dimethyl 2,5-furandicarboxylate (FDMC). γ-AlO was synthesized using a PEG surfactant to generate oxide fibers that randomly stack together into irregular shapes. The average particle sizes of the Au NPs are 1-6 nm, where the catalytically active Au (111) surface is the exposed facet. This 3D nanocatalyst architecture enhances the 5-hydroxymethylfurfural (HMF) oxidative esterification because HMF reactant molecules can readily diffuse into this fibrous structure and adsorb to active catalytic sites, while ester product molecules can diffuse out. Up to 99% HMF conversion and 90% FDMC selectivity can be obtained at a low reaction temperature of 45 °C, and the catalyst shows excellent recyclability. Increasing the Au content in the catalyst minimizes the requirement of a base for HMF conversion. Thus, the Au NPs supported on γ-AlO can drive HMF esterification to FDMC efficiently with high product selectivity under very mild reaction conditions, omitting the need for an additional esterification step of the HMF acid.
负载在纳米结构γ-氧化铝（γ-AlO）纤维上的金纳米颗粒（Au NPs）对5-羟甲基糠醛转化生成其酯衍生物2,5-呋喃二甲酸二甲酯（FDMC）表现出优异的催化活性。使用聚乙二醇表面活性剂合成γ-AlO，以生成随机堆叠成不规则形状的氧化物纤维。Au NPs的平均粒径为1-6 nm，其中具有催化活性的Au(111)表面为暴露面。这种三维纳米催化剂结构增强了5-羟甲基糠醛（HMF）的氧化酯化反应，因为HMF反应物分子能够轻易扩散到这种纤维结构中并吸附到活性催化位点上，而酯产物分子则可以扩散出去。在45℃的低温反应条件下，HMF转化率可达99%，FDMC选择性可达90%，且该催化剂具有优异的可回收性。增加催化剂中的Au含量可将HMF转化所需的碱量降至最低。因此，负载在γ-AlO上的Au NPs能够在非常温和的反应条件下高效地将HMF酯化生成FDMC，并具有高产物选择性，无需对HMF酸进行额外的酯化步骤。
