微波辅助离子液体EmimOAc提取毛竹木质素

毛竹细胞壁强的抗解构特性大大限制了毛竹作为原料在生物质能源、生物质基材料等领域的应用，因此有必要对其进行包括主要组分分离在内的预处理以提高它的使用效率。本研究采用微波辅助1-乙基-3-甲基咪唑乙酸盐（EmimOAc）法从毛竹中分离出木质素，分析所获得的木质素的物理化学特性，并与用5% NaOH（50℃，5h）提取的毛竹木质素、油浴加热（110℃，16h）EmimOAc提取的毛竹木质素进行对比。结果表明：微波辅助EmimOAc处理80min后木质素得率14.7%，比油浴加热EmimOAc提取木质素的得率（6.2%）提高了2倍以上；离子液体提取的木质素（ILL）和碱提木质素（AL）具有相似骨架结构，但在离子液体的作用下，ILL结构中有更多的酯键链接发生断裂；与AL相比，ILL具有更高的热稳定性。

Microwave-assisted extraction of lignin from bamboo by ionic liquid EmimOAc

The strong anti-deconstructive property of the bamboo （Phyllostachys pubescens Mazel） cell wall greatly limits its utilization as raw material in the fields of bioenergy, biomass-based materials, etc. Therefore, it is necessary to carry out pretreatment including main component separation to improve its utilization efficiency. In this work, microwave-assisted extraction of lignin from bamboo by using 1-ethyl-3-methylimidazolium acetate （EmimOAc） as solvent was carried out. The physicochemical properties of the obtained lignin fractions were characterized, and compared with the lignin extracted by EmimOAc using oil bath as heating source （110℃, 16h） and the alkali-soluble lignin extracted by 5% NaOH solution （50℃, 5h）. The results showed that the yield of lignin when EmimOAc was used as extractant under the microwave irradiation could reach 14.7% within 80min, which was more than twice of the yield （6.2%） when the lignin was extracted by EmimOAc using oil bath as heating source. Ionic liquid extracted lignin (ILL) and alkaline extracted lignin (AL) had a similar backbone structure, but under the effect of ionic liquid, more ester bonds between the ILL structural units were broken. Compared with AL, ILL showed higher thermal stability.