麦草碱木素臭氧氧化改性的初步研究

Preliminary Study on Ozone Oxidizing Degradation of Wheat Straw Lignin

对草类碱木素臭氧氧化改性的研究未见报道。文中首次对pH值、温度、O3用量等影响臭氧氧化的因素进行了研究 ,结果发现 ,麦草碱木素臭氧氧化比较适宜的工艺条件为 :O3用量 5 % ,pH值在中性或偏酸性条件 ,温度 2 0℃ ,在此氧化工艺条件下 ,羧基含量由 4 0 2mmol/g增加到5 66mmol/g;酚羟基含量由 2 36mmol/g增加到 3 96mmol/g。通过对不同氧化反应条件下分子质量的分布分析表明 ,在实验室O3用量范围内 ,低温情况下 ,随着O3用量的增加 ,大分子木素减少 ,分子质量分布均一化程度提高。

A very few reports about ozone oxidizing degradation of wheat straw lignin were found in literature.This paper studied the parameters of ozone oxidizing including pH value,temperature,ozone dosage.The results indicated that the optimum conditions for the ozone oxidizing were: ozone charge 5%,pH value 7～8,temperature 20℃.In this condition,—COOH content increased 1.64mmol/g,from 4.02 to 5.66 mmol/g; the Ph—OH content increased 1.60 mmol/g,from 2.36 to 3.96 mmol/g.The molecular weight distribution analysis of the products with different ozone oxidizing conditions indicated that in the optimum ozone dosage and under low temperature,high molecular weight lignin decreasing and molecular weight distribution of the lignin becomes more uniform as the ozone dosage increasing.