Division of Wood Chemistry and Pulp Technology, Department of Fiber and Polymer Technology, School of Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Wallenberg Wood Science Center, Department of Fiber and Polymer Technology, School of Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Biomacromolecules. 2024 Jul 8;25(7):4246-4254. doi: 10.1021/acs.biomac.4c00326. Epub 2024 Jun 13.
The increased interest in the utilization of lignin in biobased applications is evident from the rise in lignin valorization studies. The present study explores the responsiveness of lignin toward oxidative valorization using acetic acid and hydrogen peroxide. The pristine lignins and their oxidized equivalents were analyzed comprehensively using NMR and SEC. The study revealed ring opening of phenolic rings yielding muconic acid- and ester-end groups and side-chain oxidations of the benzylic hydroxyls. Syringyl units were more responsive to these reactions than guaiacyl units. The high selectivity of the reaction yielded oligomeric oxidation products with a narrower dispersity than pristine lignins. Mild alkaline hydrolysis of methyl esters enhanced the carboxylic acid content of oxidized lignin, presenting the potential to adjust the carboxylic acid content of lignin. While oxidation reactions in lignin valorization are well documented, this study showed the feasibility of employing optimized oxidation conditions to engineer tailored lignin-based material precursors.
从木质素在生物基应用中的利用增加的兴趣可以明显看出木质素增值研究的兴起。本研究探讨了木质素在醋酸和过氧化氢作用下氧化增值的反应性。使用 NMR 和 SEC 对原始木质素及其氧化当量进行了全面分析。研究表明，酚环开环生成富马酸和酯端基，以及苄基羟基的侧链氧化。愈创木基单元比愈创木基单元对这些反应更敏感。反应的高选择性生成了低分散度的寡聚氧化产物，比原始木质素更窄。甲酯的温和碱性水解提高了氧化木质素的羧酸含量，为调节木质素的羧酸含量提供了可能。虽然木质素增值中的氧化反应已有大量文献记载，但本研究表明可以采用优化的氧化条件来设计定制的木质素基材料前体。
