工业碱木素的纯化分级及其氨氧化研究

Purification， Fractionation and Oxiammonolysis of Industrial Alkaline Lignin

关键词:  碱木素  纯化  乙醇分级  氨氧化  肥料

Key Words:alkaline lignin  purification  ethanol fractionation  oxiammonolysis  fertilizer

摘要:利用酸析法纯化工业碱木素得到纯化碱木素，然后采用乙醇溶解分级的方法将纯化碱木素分级为不同相对分子质量的3个级分，各级分的质均相对分子质量分别为2194、2294、4237；并利用氧化剂和氨化剂使纯化碱木素及各级分发生氨氧化反应。通过傅里叶变换红外光谱仪、凯氏定氮、元素分析等方法对氨氧化前后的纯化碱木素和各级分的结构变化、氮含量进行了表征，探究不同因素对纯化碱木素氨氧化反应的影响。结果表明，纯化碱木素氨氧化反应的最佳条件为：纯化碱木素用量10%，氨水用量30%，H₂O₂用量20%，反应温度45℃，反应时间1.5 h。在最佳氨氧化反应条件下，质均相对分子质量低的级分1的氨氧化产物C∶N数值较低，总氮含量较高（可达13.06%），适宜用作肥料。

Abstract:The industrial alkaline lignin was purified by acid precipitation and classified into fractions of different molecular weights by fractional dissolution with ethanol， then it was carried out oxiammonolysis reaction with clean oxidants and ammonizators. FT-IR， the Kjeldahl and elemental analysis methods were used to characterize the structural changes of different fractions， structural changes after oxiammonolysis and nitrogen content of purified alkaline lignin， which were helped to research the effects of different factors on the oxiammonolysis. The results showed that the optimal reaction conditions were as followes, 10% alkaline lignin concentration， 30% ammonia charge， 20% hydrogen peroxide dosage， 45℃ reaction temperature， 1.5 h reaction time.The nitrogen content after the oxiammonolysis under the operating conditions increased significantly, and the ratio of carbon to nitrogen of the purified alkaline lignin decreased as the molecular weight decreased， which could be used as fertilizer．