脱氢二香草醇的合成及LCC的形成机理(Ⅰ)

Synthesis of Condensed Lignin Model Compound and the Formation Mechanism of LCC during Kraft Cooking(Ⅰ)

合成了一种缩合型木素模型化合物——脱氢二香草醇,并利用红外光谱、核磁共振谱(1H-NMR)对其进行了分析和确认。在此基础上,模拟硫酸盐法蒸煮过程,将合成的木素模型物和典型的半纤维素组成部分(木聚糖)进行蒸煮,然后利用酸析沉淀木素、乙酸乙酯抽提的方法将蒸煮后的产物分级,并利用FT-IR、13C-NMR对分级后的各个部分进行分析,探讨传统硫酸盐法制浆过程中木素-碳水化合物复合体(LCC)的形成机理。研究发现脱氢二香草醇在硫酸盐法蒸煮过程中非常稳定,残留的脱氢二香草醇以及新形成的LCC主要存在于酸不溶物、乙酸乙酯抽提物中,大部分未降解的木聚糖存在于酸不溶物中,碱不溶物和酸可溶物内都不存在新形成的LCC结构。

Dehydro-divanillylalcohol was synthesized with a modified method as a type of condensed lignin model compound. The technique of FT-IR and ^1H-NMR were used to identify the chemical structure. After the lignin model compound was synthesized, it was cooked by kraft method in existence of xylan. The products from lignin model compound cooked by kraft method were separated by acidification and ethyl acetate extraction. The combination of infrared spectra analysis and ^13C-NMR were used to identify the lignin-carbohydrate complexes （LCC） formed during kraft cooking. The research indicated that dehydro-divanillylalcohol was very stable during cooking by Kraft method. Most of undegraded dehydro-divanillylalcohol and new formation LCC structure existed in acid insoluble residue and ethyl acetate extractive in existence of xylan. Most of undegraded xylan was existed in the acid insoluble residue. No newly formed LCC structure was found in the acid soluble residue and alkali insoluble residue.