Institute of Biomass Chemistry and Technology, Beijing Forestry University, Beijing, China.
Ultrason Sonochem. 2012 Mar;19(2):243-9. doi: 10.1016/j.ultsonch.2011.06.018. Epub 2011 Jul 5.
Bamboo was submitted to ultrasound-assisted extraction in aqueous ethanol to evaluate the effect of ultrasonic irradiation on the dissolution of lignin. In this case, the dewaxed bamboo culms were subjected to ball milling for 48 h, and then were suspended in 95% ethanol followed by ultrasonic irradiations for varied times at 20 °C to obtain ethanol-soluble fractions. The structural and thermal properties of the ethanol-soluble fractions were comparatively investigated by chemical analysis including alkaline nitrobenzene oxidation, bound carbohydrate determination, FT-IR spectra, HSQC spectra, TG, and DTA. The results showed that the yields of the ethanol-soluble fractions were between 4.29% and 4.76% for the fractions prepared with ultrasonic irradiation time ranging from 5 to 55 min, as compared to 4.02% for the fraction prepared without ultrasonic irradiation. It was found that the lignin content of the fraction increased with the increase of the ultrasonic irradiation time. There was a slight increase of the molecular weight of the lignin with the increase of the ultrasonic irradiation time. Alkaline nitrobenzene oxidation coupled with HSQC analysis indicated that the lignin in the fractions was mainly composed of GSH type units as well as minor amounts of ferulic acids. In addition, the fraction prepared with ultrasonic irradiation exhibited a slightly higher thermal stability as compared to the fraction prepared without ultrasonic irradiation.
竹子被提交到水乙醇中的超声辅助提取中，以评估超声辐射对木质素溶解的影响。在这种情况下，对脱蜡的竹秆进行了 48 小时的球磨，然后悬浮在 95%的乙醇中，随后在 20°C 下进行不同时间的超声辐射，以获得乙醇可溶部分。通过化学分析，包括碱性硝基苯氧化、结合碳水化合物测定、FT-IR 光谱、HSQC 光谱、TG 和 DTA，比较研究了乙醇可溶部分的结构和热性能。结果表明，与未进行超声辐射的部分（4.02%）相比，超声辐射时间为 5 至 55 分钟的部分的乙醇可溶部分的产率在 4.29%至 4.76%之间。发现木质素含量随超声辐射时间的增加而增加。随着超声辐射时间的增加，木质素的分子量略有增加。碱性硝基苯氧化与 HSQC 分析相结合表明，该部分中的木质素主要由 GSH 型单元以及少量的阿魏酸组成。此外，与未进行超声辐射的部分相比，经超声辐射制备的部分表现出稍高的热稳定性。
