Conversion of platform molecule 5-hydroxymethylfurfural (HMF) into high-value-added derivatives has attracted significant interest. In this paper, a metallic cobalt catalyst was prepared by the simple reduction of commercially available Co₃O₄, and used to catalyze the reductive etherification of HMF to 2,5-bis(methoxymethyl)furan (BMMF) under mild conditions. A yield of 93% 2,5-bis(hydroxymethyl)furan (BHMF) was obtained (90 °C, 2 MPa H₂, 1 h) and 98.5% yield of BMMF was achieved (140 °C, 2 MPa H₂, 1 h) by using a Co-400 catalyst. The catalysts were characterized by X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), ammonia-temperature-programmed-desorption (NH₃-TPD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). It was found that the Co⁰ and Co^2+/3+ species coexist on the surface of the catalyst and the catalyst became more porous and rougher after reduction at high temperature. This may be more beneficial for enhancing the selectivity of the etherification product and the mass transfer of reaction species. A possible reaction mechanism was proposed based on GC and ¹H-NMR analyses. The cobalt catalyst was reused five times with a slight decrease in activity.

中文翻译：

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一种在温和条件下将5-羟甲基糠醛还原醚化为2,5-双（甲氧基甲基）呋喃的钴催化剂

平台分子5-羟甲基糠醛（HMF）转化为高附加值的衍生物引起了人们的极大兴趣。本文通过简单还原市售Co ₃ O ₄制备金属钴催化剂，并在温和条件下将其催化HMF还原醚化为2,5-双（甲氧基甲基）呋喃（BMMF）。获得了93％的2,5-双（羟甲基）呋喃（BHMF）产率（90°C，2 MPa H _2，1 h），达到了98.5％的BMMF产率（140°C，2 MPa H ₂，）。 1 h）使用Co-400催化剂。通过X射线光电子能谱（XPS），粉末X射线衍射（XRD），氨程序升温脱附（NH ₃）对催化剂进行了表征。-TPD），扫描电子显微镜（SEM），透射电子显微镜（TEM）和电感耦合等离子体原子发射光谱（ICP-AES）。发现在催化剂表面上共存有Co ⁰和Co ^{2 + / 3 +}物种，并且在高温下还原后，催化剂变得更多孔且更粗糙。这对于增强醚化产物的选择性和反应物质的传质可能是更有益的。基于GC和¹ H-NMR分析，提出了可能的反应机理。钴催化剂被重复使用了五次，但活性略有下降。