Department of Chemistry, P.O. Box 55, 00014, University of Helsinki, Helsinki, Finland.
J Agric Food Chem. 2012 Sep 12;60(36):8968-73. doi: 10.1021/jf303003d. Epub 2012 Aug 27.
The accurate and reproducible determination of lignin molar mass by using size exclusion chromatography (SEC) is challenging. The lignin association effects, known to dominate underivatized lignins, have been thoroughly addressed by reaction with acetyl bromide in an excess of glacial acetic acid. The combination of a concerted acetylation with the introduction of bromine within the lignin alkyl side chains is thought to be responsible for the observed excellent solubilization characteristics acetobromination imparts to a variety of lignin samples. The proposed methodology was compared and contrasted to traditional lignin derivatization methods. In addition, side reactions that could possibly be induced under the acetobromination conditions were explored with native softwood (milled wood lignin, MWL) and technical (kraft) lignin. These efforts lend support toward the use of room temperature acetobromination being a facile, effective, and universal lignin derivatization medium proposed to be employed prior to SEC measurements.
准确且可重现地通过尺寸排阻色谱（SEC）测定木质素的摩尔质量具有挑战性。木质素缔合效应在未衍生木质素中占主导地位，已通过在过量冰醋酸中与溴化乙酰反应得到彻底解决。协同乙酰化与木质素烷基侧链中溴的引入相结合，被认为是导致观察到的各种木质素样品的出色溶解特性的原因。该方法与传统木质素衍生化方法进行了比较和对比。此外，还研究了在室温溴化乙酰化条件下可能引发的副反应，涉及天然软木（磨木木素，MWL）和技术（硫酸盐）木质素。这些努力支持使用室温溴化乙酰化作为一种简便、有效和通用的木质素衍生化介质，该介质建议在 SEC 测量之前使用。
