Rinesch Torsten, Bolm Carsten
Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
ACS Omega. 2018 Jul 30;3(7):8386-8392. doi: 10.1021/acsomega.8b00994. eCollection 2018 Jul 31.
In this work we demonstrate the use of Co(acac) in combination with -hydroxyphthalimide as an oxidant for the selective α-oxidation of the representative β-O-4 linkages in lignin model compounds. The oxidation reaction proceeds under mild conditions at 80 °C using 1,4-dioxane as the solvent and an oxygen atmosphere. The prior α-oxidation in the β-O-4 linkage of the lignin polymer is known to result in an easier cleavage of the adjacent C-O and C-C bonds because of a decrease in bond stability. Finally, the conditions were successfully transferred to kraft- and organosolv-lignin samples as proven by 2D-NMR (HSQC) experiments and gel permeation chromatography measurements.
在本工作中，我们展示了使用Co(acac)与α-羟基邻苯二甲酰亚胺组合作为氧化剂，用于木质素模型化合物中代表性β-O-4键的选择性α-氧化。氧化反应在80°C的温和条件下，以1,4-二氧六环为溶剂并在氧气气氛中进行。已知木质素聚合物β-O-4键中的α-氧化会导致相邻C-O键和C-C键因键稳定性降低而更容易断裂。最后，二维核磁共振（HSQC）实验和凝胶渗透色谱测量证明，这些条件成功应用于硫酸盐木质素和有机溶剂木质素样品。
