PDF(Pubmed)
Abstract：
Lignin, a natural pol2ymer with a complex structure that is difficult to separate, is prone to C-C bond condensation during the separation process. To reduce the condensation of lignin, here, a novel method is proposed for separating the components by using a combination of maleic acid (MA)/ozone (O3) to co-treat wheat straw. The removal of lignin, glucan, and xylan was 38.07 ± 0.2%, 31.44 ± 0.1%, and 71.98 ± 0.1%, respectively, under the conditions of ball-milling of wheat straw for 6 h, reaction temperature of 60 °C, and O3 holding time of 9 min. Lignin-rich solutions were collected to extract the dissolved lignin (DL) after washing the treated samples. The DL obtained under MA/O3 conditions had a carboxyl group (-COOH) content of 2.96 mmol/g. The carboxyl group of MA underwent esterification with the hydroxyl group (-OH) at the γ position of lignin and O3 reacted on the positions of the lignin side chain or the phenolic ring, resulting in a break in the side chain and the opening of the phenolic ring to introduce the carboxyl group. The 2D-HSQC-NMR results revealed that the phenolic ring-opening reaction of lignin in the presence of O3 was essentially free of β-β and β-5 condensation bonds.
摘要：
木质素,一种复杂结构难以分离的天然聚合物，在分离过程中容易发生C-C键缩合。为了减少木质素的凝结，在这里，提出了一种通过使用马来酸（MA）/臭氧（O3）的组合来分离小麦秸秆的新方法。木质素的去除，葡聚糖,木聚糖为38.07±0.2%，31.44±0.1%,和71.98±0.1%，分别,在小麦秸秆球磨6小时的条件下，反应温度60℃,和O3的保持时间为9分钟。在洗涤处理过的样品后,收集富含木质素的溶液以提取溶解的木质素(DL)。在MA/O3条件下获得的DL具有2.96mmol/g的羧基(-COOH)含量。MA的羧基与木质素γ位的羟基（-OH）进行酯化，O3在木质素侧链或酚环的位置反应，导致侧链的断裂和酚环的打开以引入羧基。2D-HSQC-NMR结果表明，在O3存在下木质素的酚开环反应基本上不含β-β和β-5缩合键。
