Center for Environmentally Beneficial Catalysis, University of Kansas, Lawrence, KS, 66047, USA.
Current address: School of Arts and Sciences, Ottawa University, Ottawa, KS, 66067.
ChemSusChem. 2022 Jul 7;15(13):e202102050. doi: 10.1002/cssc.202102050. Epub 2022 Jan 10.
The oxidation of 5-hydroxymethylfurfural (HMF) produces value-added chemicals such as 2,5-diformylfuran (DFF) and 2,5-furandicarboxylic acid (FDCA). In this work, FDCA production was achieved by oxidation of crude HMF solution containing around 45 % HMF and unwanted byproducts such as 5,5'-[oxy-bis(methylene)]bis-2-furfural (HMF dimer) and polymers. At optimized reaction conditions similar to the Mid-Century process, homogeneous oxidation of the crude HMF (up to 20 wt% in the feed) by Co/Mn/Br catalyst in acetic acid solution produced FDCA at >95 % yield. The solid FDCA product contained <4000 ppm 5-formyl-2-furancarboxylic acid (FFCA). Such high yields were observed because the impurities in crude HMF were also converted to FDCA, as confirmed by the facile oxidation of HMF dimer to FDCA under reaction conditions. The successful demonstration of crude HMF as feed, obviating the need for HMF purification, suggests potential for cost-effectively producing FDCA in existing terephthalic plants.
5-羟甲基糠醛（HMF）的氧化可以产生增值化学品，如 2,5-二糠醛（DFF）和 2,5-呋喃二甲酸（FDCA）。在这项工作中，通过氧化含有约 45% HMF 和不需要的副产物（如 5,5'-[氧-双（亚甲基）]双-2-糠醛（HMF 二聚体）和聚合物）的粗 HMF 溶液实现了 FDCA 的生产。在与中世纪工艺相似的优化反应条件下，Co/Mn/Br 催化剂在乙酸溶液中对粗 HMF（进料中高达 20wt%）的均相氧化产生了>95%收率的 FDCA。固体 FDCA 产品中含有<4000ppm 的 5-糠醛-2-羧酸（FFCA）。之所以能够观察到如此高的收率，是因为粗 HMF 中的杂质也转化为 FDCA，这一点通过在反应条件下 HMF 二聚体易于氧化为 FDCA 得到了证实。成功地以粗 HMF 为原料进行了示范，无需进行 HMF 纯化，这表明在现有的对苯二甲酸装置中以经济有效的方式生产 FDCA 具有潜力。
