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摘要木质素是一类由苯基丙烷单元通过碳碳键和醚键无规则连接而形成的无定形和高度支化的有机高分子聚合物。它具有可再生性，是一种储量丰富、廉价易得的可降解物质，可作为获取洁净能源和化学品的原料而受到广泛关注。39448
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木质素的氧化降解研究主要通过两种方法来进行的，即高温高压法和温和条件法。温和条件下木质素的氧化降解是以无机盐或金属酞菁化合物作为催化剂，以双氧水或氧气为氧化剂，对木质素进行氧化研究。当木质素5.0g，0.3g 催化剂，氢氧化钠浓度2.0mol/L，氧化剂与木质素的体积质量比为3.0，反应温度35℃，反应时间30min，无机盐CuSO4•5H2O作为催化剂时，木质素的降解粗产物达到19.2%，其中芳香化合物在粗产物中的比率为35.2%，通过柱层析分离得到的香草醛产率为3.2%；当CoPc作为催化剂，木质素的降解粗产物达到17.9%，其中芳香化合物在粗产物中的比率为33.4%。通过柱层析分离得到的香草醛产率为2.9%。该法反应条件温和，所用氧化剂为氧气或双氧水，为绿色氧化剂，对环境无污染，反应时间短，对反应设备要求低，为木质素在工业上的广泛应用提供了条件。
毕业论文关键词：木质素；氧化降解；双氧水/氧气；
Process of preparing an aromatic aldehyde by oxidative degradation of lignin
ABSTRACT
Lignin is a class of amorphous and highly branched organic polymer composed of phenylpropane units, in which large number of aromatic rings link together through C–O–C and C–C bonds. It is a rich source of compounds which is renewable, cheap and readily available biodegradable material and can be used as raw material to obtain clean energy and chemicals, and has attracted widespread attention.
Oxidation degradation of lignin is mainly carried out by two methods, namely, high temperature and pressure method and mild method. Oxidative degradation of lignin under mild conditions was used inorganic salts or metal phthalocyanine compound as a catalyst, hydrogen peroxide or oxygen as the oxidant. In the condation of lignin 5.0g, catalyst 0.3g, sodium hydroxide concentration 2.0mol/L, the volume and quality ratio of oxidant and lignin was 3.0, the reaction temperature 35℃, reaction time 30min, when inorganic salt CuSO4•5H2O was used as catalyst, the degradative crude product of lignin was reached 19.2%, wherein the aromatic compounds accounted for 35.1% in the crude product, vanillin separated by column chromatography obtained in a yield of 3.2%; when metal phthalocyanine compound CoPc was used as catalyst, the degradative crude product of lignin was reached 17.9%, wherein the aromatic compounds accounted for 33.4% in the crude product, vanillin separated by column chromatography obtained in a yield of 2.9%. This method has an advantage of mild reaction conditions, and used oxygen or hydrogen peroxide as oxidant, which is green oxidant and no environmental pollution, short reaction time, low equipment requirements, which provided the conditions for lignin in a wide range of industrial applications.
KeyWords: Lignin; Oxidative degradation; Application
目 录
1 引言 1
1.1 木质素 1
1.1.1 木质素的结构与性质 1
1.1.2 木质素的应用现状 3
1.2 国内外木质素的降解现状 5
1.3 木质素降解制备芳香醛的工艺方法 6
1.3.1 生物催化 6
1.3.2 仿生催化氧化 6
1.3.3 过渡金属催化氧化法 6
1.3.4 其他催化氧化 7
1.4 选题的意义 9
1.5 创新点 9
2 实验部分 10