Abstract

The main goal of this study was the elucidation of structures of products of oxidation of industrial hydrolysis lignin (HL) obtained in the system H₂O₂-H₂SO₄-H₂O. It was found that the obtained oxidized hydrolysis lignin (OHL) contained structural fragments of muconic acid dilactone. The latter appeared as a result of the oxidation of aromatic ring of HL into unstable structures of 3,4-dihydroxyadipic acid, which are spontaneously cyclized into the corresponding fragments of muconic acid dilactone in acidic oxidative medium. Consequent reaction of OHL with aqueous sodium hydroxide (NaOH) led to the formation of sodium salt of OHL (Na-OHL), in which the muconic acid dilactone units of OHL opened into fragments of disodium salts of 3,4-dihydroxyadipic acid. The Na-OHL was transformed into the series of novel derivatives of lignins. Thus, the reaction of Na-OHL with thionyl chloride proceeded as a substitution of hydroxyl groups into chlorine atoms in the structure of OHL, that afforded chloro-derivative of OHL. The latter was transformed into amino-amide and ester-ether derivatives of OHL by nucleophilic substitution of chlorine atoms with amines and alcohols correspondingly.

摘要

_{本研究的主要目标是阐明在 H 2} O ₂ -H ₂ SO ₄ -H ₂系统中获得的工业水解木质素 (HL) 氧化产物的结构O. 发现所获得的氧化水解木质素(OHL)含有粘康酸双内酯的结构片段。后者的出现是由于 HL 的芳环被氧化成不稳定的 3,4-二羟基己二酸结构，在酸性氧化介质中自发环化成相应的粘康酸双内酯片段。OHL 与氢氧化钠水溶液 (NaOH) 的后续反应导致形成 OHL 的钠盐 (Na-OHL)，其中 OHL 的粘康酸双内酯单元打开成 3,4-二羟基己二酸的二钠盐片段。Na-OHL转化为一系列新型木质素衍生物。因此，Na-OHL 与亚硫酰氯的反应是将羟基取代为 OHL 结构中的氯原子，这提供了 OHL 的氯代衍生物。后者通过相应地用胺和醇亲核取代氯原子而转化为OHL的氨基-酰胺和酯-醚衍生物。