Elucidaton of the formation mechanism and characteristics of acid-soluble lignin, and conversion of lignin into functional material

本研究主要研究：(1)阐明酸溶性木质素的形成机理和特性，(2)木质素转化为功能材料。选取结构高度凝聚的硫酸木质素（SAL）作为木质素样品。(1)阐明酸溶木质素的形成机理和特性。以山毛榉为原料制备的酸溶木质素（ASL）由约一半的氯仿可溶性木质素和一半的水溶性木质素组成。愈创木酰和紫丁香木质素模型化合物在72%硫酸（SA）中与碳水化合物反应表明，紫丁香木质素与半纤维素缩合形成水溶性ASL。此外，紫丁香基木质素模型化合物在72% SA中的降解反应表明，紫丁香基烷基醚键被水解形成可溶于氯仿的低分子量SAL降解产物。(2)木质素转化为功能材料为了开发有效利用酸解木质素的新方法，研究了SAL作为典型的酸解木质素的化学转化为功能材料。首先，以SAL和72% SAL的酚醛化SAL （p-SAL）为原料，在水溶性SAL模型上制备了以糖类组分为亲水基团的中性表面活性剂。然而，在72% SA条件下，缩合型木质素模型化合物与单糖反应得到的c -糖苷产率很低。在SAL和/或P-SAL中引入羧甲基和二甲氨基甲基基团的尝试分别成功地从P-SAL中制备了可溶性酸性和阳离子表面活性剂。每C_9-C_6单位（对羟基）愈创木酰基甲基单位)含量分别为1.4和1.3个。

This research studied on (1) elucidaton of the formation mechanism and characteristics of acid-soluble lignin, and (2) conversion of lignin into functional material. Sulfuric acid lignin (SAL) with highly condensed structures was selected as a lignin sample.( 1 ) Elucidaton of the formation mechanism and characteristics of acid-soluble lligninAcid soluble lignin (ASL) prepared from beech was composed of about half the amount of chloroform-soluble ASL and the rest half the amount of water-soluble ASL. Reaction of guaiacyl and syringyl lignin model compounds with carbohydrates iin 72% sulfuric acid (SA) suggested that water-soluble ASL is formed by condensation of syringyl lignin with hemicellulose. Furthermore, degradation reaction of syringyl lignin model compounds in 72% SA indicated that syringyl alkyl ether linkages are hydrolyzed to form chloroform-soluble low molecular weight degradation products of SAL.( 2 ) Conversion of lignin into functional materialTo develop new methods for effective utilization of acid hydrlysis lignin, chemical conversion of SAL as a typical acid hydrolysis lignin into funcrional material was investigated. at first, preparation of neutral surfactant with carbohydrate component as a gydrophilic group from SAL and phenolized SAL (p-SAL) in 72% SAL on the model of water-soluble ASL was tried. However, reaction of condensed-type lignin model compounds with monosaccharides in 72% SA gave the expected C-glycosides only in low yields. Attempts to introduce carboxymethyl and dimethylaminomethyl groups into SAL and/or P-SAL were successful to prepare soluble acidic and cationic surfactants from P-SAL, respetively, in quantitative yields. The content of the groups was 1.4 and 1.3 per C_9-C_6 unit (p-hydroxypheny) guaiacyl methyl unit), respectively.