【作者】 沈艳尼；

【导师】 樊永明；

【作者基本信息】 北京林业大学 ， 林产化学加工工程， 2008， 硕士

【摘要】 研究制浆过程中木素-碳水化合物复合体(LCC)的结构变化是彻底除去木素的关键问题。本论文以麦草LCC为研究对象,经过甲酸处理和分离提纯,运用气相色谱、红外光谱、核磁共振、气质联用等仪器分析方法,对LCC处理前后进行分析,比较其结构变化,并首次以麦草木素和木糖为研究对象,探讨木素与碳水化合物在蒸煮过程中形成新LCC的可能性。研究结果表明:1.麦草LCC中木素主要与木糖和葡萄糖相联结。经甲酸处理时,葡萄糖与木素的联结相对较稳定。2.麦草LCC中有木素、纤维素和半纤维素的特征存在。经甲酸处理后,碳水化合物被降解,木素含量相对增加。3.麦草LCC经甲酸处理后,芳香族物质明显增加,脂肪族物质大幅度减少,说明碳水化合物相对减少,木素含量相对增加。LCC中与碳水化合物形成酯键联结的木素以及部分β-O-4结构对甲酸相当稳定。4.甲酸处理后酸溶产物中愈疮木基型(G)和紫丁香基型(S)的色谱峰面积之比为34.57%∶20.82%。降解产物中存在有香草醛和香草酸等低分子产物。5.麦草木素与木糖经甲酸混合处理时,木糖与木素之间产生了新的酚醚键,并可能产生苯甲醚键结合本论文发现麦草LCC对甲酸不稳定,并证实了木素与碳水化合物之间在蒸煮过程中存在重新结合的可能,为甲酸制浆工艺的确定提供理论支持,对优化制浆工艺、强化脱木素效率、提高产品质量都有十分重要的意义。更多还原

【Abstract】 In order to remove lignin completely, we need to understand the changes in the strcture of Lignin-Carbohydrate Complex during the process of pulp. In this paper, LCC of wheat straw was decomposed with formic acid and the new forms LCC were produced between wheat lignin and carbohydrate for the first time. The fomic acid treated LCC were analyzed by elementary analysis, 1H-NMR, 13C-NMR, FTIR, GC and GC-MS and were compared with Lignin-Carbohydrate Complex.The results were as follows:1. In wheat straw LCC, lignin was mainly combinated with xylose and glucose. After formic acid, glucose was comparatively stable.2. The characteristics of lignin, cellulose and hemicellulose are existed in LCC of wheat straw. Through acid treatment, the carbohydrates in LCC were degradated and the lignin content was increased.3. After formic acid processing, the aromatic series was obviously increased, and fatty group was reduced, which showed the content of lignin was increased. The lignin in LCC, which was combined with carbohydrate by ester linkage, as well as a part ofβ-O-4 structures, were quite stable in formic acid.4. The ratio between G and S unit was 38.30% to 20.82% in the acid dissolved product. In the degradated product, vanilla aldehyde and vanilla acid were existed. The lignin on the side chain position were oxidated to cause linkage broken and new hydroxyl and carbonyl increased.5. The new phenol ether bonds were produced between the xylose and lignin, and benzonitrile ether bonds were probably formed, when MWL and xylose were treated with formic acid.In this paper, it is discovered the wheat straw LCC was unstable in formic acid, and confirmed the new linkage was produced between the lignin and the carbohydrate. It is significant to optimize the pulping process, remove lignin and improve product quality.更多还原