Wang Zhi, Xie Yimin, Zhao Boxuan
Research Institute of Pulp & Paper Engineering, Hubei University of Technology, Wuhan 430068, China.
Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan 430068, China.
Molecules. 2025 Feb 26;30(5):1077. doi: 10.3390/molecules30051077.
In this study, a modified synthetic method for labeling a lignin dimer (guaiacylglycerol-β-guaiacyl ether-[α-C]) was developed. The chemical structure of the target compound was analyzed using H-NMR, C-NMR, and other analytical techniques. Then, the C-labeled phenolic lignin model compound was subjected to kraft pulping in the presence of xylose. Finally, the resulting reaction products were fractionated using acid precipitation and ethyl acetate extraction, and each fraction was analyzed by carbon-13 nuclear magnetic resonance (C-NMR) and two-dimensional heteronuclear multiple quantum coherence (HMQC) spectroscopy. This aimed to investigate the occurrence of lignin-carbohydrate complexes (LCCs) during the conventional kraft pulping process. Employing ethanol as the reaction medium facilitated the bromination of 4-acetylguaiacol-[α-C], resulting in a homogeneous reaction and significantly improving the yield of the brominated product to over 90%. Additionally, kraft pulping of the phenolic lignin model compound in the presence of xylose led to the occurrence of minor quantities of benzyl ether-type lignin-carbohydrate complex (LCC) structures, which were predominantly detected in the ethyl acetate extractive.
在本研究中，开发了一种用于标记木质素二聚体（愈创木基甘油-β-愈创木基醚-[α-C]）的改进合成方法。使用氢核磁共振（H-NMR）、碳核磁共振（C-NMR）和其他分析技术对目标化合物的化学结构进行了分析。然后，将碳标记的酚类木质素模型化合物在木糖存在下进行硫酸盐制浆。最后，使用酸沉淀和乙酸乙酯萃取对所得反应产物进行分馏，并通过碳-13核磁共振（C-NMR）和二维异核多量子相干（HMQC）光谱对每个馏分进行分析。这旨在研究传统硫酸盐制浆过程中木质素-碳水化合物复合体（LCCs）的形成情况。以乙醇作为反应介质促进了4-乙酰基愈创木酚-[α-C]的溴化反应，得到了均相反应，并显著提高了溴化产物的产率至90%以上。此外，酚类木质素模型化合物在木糖存在下进行硫酸盐制浆会导致少量苄基醚型木质素-碳水化合物复合体（LCC）结构的形成，这些结构主要在乙酸乙酯提取物中被检测到。
