| 李歆科,赵鑫,朱宏伟,王兴,周景辉.乙二醇抑制DES预处理过程中木质素缩合程度的研究[J].中国造纸学报,2022,37(4):39-46 |
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| 乙二醇抑制DES预处理过程中木质素缩合程度的研究 |
| Research of Inhibiting Lignin Condensation by Ethylene Glycol During DES Pretreatment Process |
| 投稿时间：2022-08-29 |
| DOI：10.11981/j.issn.1000-6842.2022.04.39 |
| 中文关键词: 低共熔溶剂 抑制缩合 木质素分馏 木质素 |
| Key Words:deep eutectic solvent condensation inhibition lignin fractionation lignin |
| 基金项目:国家自然科学基金面上项目（22278046，22078035）。 |
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| 中文摘要: |
| 利用氯化胆碱/草酸和氯化胆碱/草酸/乙二醇2种低共熔溶剂（DES）体系预处理竹粉以分馏提取木质素，并通过多种表征手段探究木质素的结构变化。结果表明，在110 ℃反应180 min的条件下，氯化胆碱/草酸二元DES体系提取的木质素（二元DES木质素）中β-O-4芳基醚键的相对含量仅为0.26/Ar，氯化胆碱/乙二醇/草酸三元DES体系提取的木质素（三元DES木质素）此值则为0.43/Ar。同时，二元DES木质素中的缩合结构（β-β，β-5=3.11/Ar）及缩合的芳环C—C连接（Aromatic C—C=2.18/Ar）多于三元DES木质素（β-β，β-5=2.02/Ar，Aromatic C—C=1.99/Ar）。利用超声辅助三元DES体系预处理过程，发现反应20 min后木质素脱除率即可达76.0%。采用水相电位滴定法测定不同反应条件下的三元DES木质素的酚羟基和羧基含量；并提出乙二醇在三元DES体系预处理竹粉过程中抑制木质素缩合的机理，证实乙二醇与对香豆酸和阿魏酸反应生成了酯化的木质素结构。 |
| Abstract: |
| Lignin was fractionated from bamboo powder with different deep eutectic solvent （DES） systems， i.e.， the binary choline chloride/oxalic acid and the ternary choline chloride/ethylene glycol/oxalic acid， and the changes in lignin structure were investigated by various characterization methods. The results showed that the relative β-O-4 aryl ether bond content of binary DES lignin was merely 0.26/Ar and that of the ternary DES lignin was 0.43/Ar at the same processing condition of 110 ℃ for 180 min. Meanwhile， the condensed structure （β-β， β-5=3.11/Ar） and condensed aromatic C—C bond （Aromatic C—C=2.18/Ar） of binary DES lignin were more than those of ternary DES lignin （β-β， β-5=2.02/Ar， Aromatic C—C=1.99/Ar）. The lignin removal rate reached 76.0% after 20 min of reaction with ultrasound-assisted ternary DES pretreatment. The contents of phenolic hydroxyl and carboxyl groups of ternary DES lignin under different reaction conditions were determined by aqueous potentiometric titration. The mechanism of ethylene glycol inhibiting lignin condensation during the pretreatment of bamboo powder with ternary DES system was put forward， and the reaction of ethylene glycol with p-coumaric acid and ferulic acid was proved to produce esterified lignin structure. |
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