Cleavage of lignin ether bonds via transfer hydrogenolysis is a promising route to valorize lignin, but processes that use mild reaction conditions and exploit renewable hydrogen donor solvents (rather than molecular hydrogen) are economically advantageous. Herein we demonstrate the efficient catalytic transfer hydrogenolysis and tandem decarbonylation of lignin model compounds possessing aromatic ether bonds (α-O-4, β-O-4 and 4-O-5 linkages), over transition metal-modified Pd hydrotalcite catalysts with ethanol as the hydrogen donor and solvent. Quantitative conversions and yields were attained for all model compounds, except for 4-O-5 models, which possess inherently strong sp² C-O bonds. The latter demonstrates the utility of Pd hydrotalcite catalysts for transfer hydrogenolysis of model compounds. This process was employed to achieve whole pine biomass delignification with 97% yield and a 22% phenolic monomer yield, with 64% selectivity for 4-(3-hydroxypropyl)-2-methoxyphenol.

中文翻译：

---

使用 Pd/水滑石催化剂通过转移氢解进行选择性木质素解聚：将化合物建模为全生物质


通过转移氢解裂解木质素醚键是使木质素增值的一种很有前途的途径，但使用温和反应条件并利用可再生氢供体溶剂（而不是分子氢）的工艺在经济上具有优势。在此，我们展示了具有芳香醚键（α-O-4、β-O-4 和 4-O-5 键）的木质素模型化合物在以乙醇作为氢供体和溶剂的过渡金属改性 Pd 水滑石催化剂上的高效催化转移氢解和串联脱羰。所有模型化合物均获得了定量转化率和产率，但 4-O-5 模型除外，它们本身具有很强的 sp² C-O 键。后者证明了 Pd 水滑石催化剂在模型化合物转移氢解中的实用性。采用该工艺实现全松生物质脱木素，产率为 97%，酚类单体产率为 22%，对 4-（3-羟丙基）-2-甲氧基苯酚的选择性为 64%。