Shanghai Key Laboratory of Functional Materials Chemistry, Research Institute of Industrial Catalysis;, School of Chemistry and Molecular Engineering, East China University of Science and Technology, No. 130 Meilong Road, Shanghai, 200237, P. R. China.
ChemSusChem. 2018 Aug 22;11(16):2758-2765. doi: 10.1002/cssc.201800967. Epub 2018 Jul 16.
The complete transformation of lignocellulosic biomass into valuable platform chemicals is of great significance. Herein, a catalytic process for the upgrading of lignocellulose to arenes, 5-hydroxymethylfurfural (HMF), and furfural is reported. Firstly, the lignin fraction in lignocellulosic biomass is selectively converted into lignin oil (82.9 mol % yield of lignin monomers from birch wood) over a Pd/C catalyst and then further hydrodeoxygenated to arenes in catalytic hydrogen-transfer reactions over a Ru/Nb O catalyst. High yields of C -C hydrocarbons (95.6 mol %) with 85.6 wt % selectivity to arenes based on lignin oil are achieved owing to the synergistic effect between Ru and Nb O , which enables direct hydrogenolysis of the C -OH bond in phenolics. Secondly, the cellulose and hemicellulose fractions in the Pd/C-containing solid residue, as well as methylated C sugars produced during the stripping of lignin, are converted into HMF and furfural with a total yield of up to 24.5 wt % (based on the amount of birch wood) in a THF/concentrated seawater (ca. 30 wt % salts) biphasic reaction system. Here, seawater played a key role in the conversion of cellulose and hemicellulose into HMF and furfural, respectively; more importantly, it made the separation and reuse of the Pd/C catalyst easier. With this catalytic process, the complete and efficient transformation of lignocellulose into highly value-added products with recycling of each catalyst and solvent has been realized.
将木质纤维素生物质完全转化为有价值的平台化学品具有重要意义。本文报道了一种将木质纤维素转化为芳烃、5-羟甲基糠醛（HMF）和糠醛的催化过程。首先，在 Pd/C 催化剂上选择性地将木质纤维素中的木质素部分转化为木质素油（桦木木质素单体收率为 82.9 mol%），然后在 Ru/Nb 2 O 催化剂上通过催化氢转移反应进一步将其加氢脱氧转化为芳烃。由于 Ru 和 Nb 2 O 之间的协同作用，木质素油中 C-C 烃（95.6 mol%）的产率高达 85.6 wt%，芳烃选择性高达 85.6 wt%，这是因为酚类中的 C -OH 键可以直接发生氢解。其次，Pd/C 固体残渣中的纤维素和半纤维素部分，以及在木质素汽提过程中生成的甲基化 C 糖，在 THF/浓缩海水（约 30 wt%盐）两相反应体系中转化为 HMF 和糠醛，总收率高达 24.5 wt%（基于桦木量）。在这里，海水在纤维素和半纤维素分别转化为 HMF 和糠醛方面发挥了关键作用；更重要的是，它使得 Pd/C 催化剂的分离和再利用变得更容易。通过这种催化过程，实现了木质纤维素的完全和高效转化，生成了高附加值产品，同时催化剂和溶剂得到了循环利用。
