Wageningen University, Food and Biobased Research, Wageningen, The Netherlands.
Bioresour Technol. 2012 Feb;106:173-7. doi: 10.1016/j.biortech.2011.11.121. Epub 2011 Dec 4.
Valorisation of lignin plays a key role in further development of lignocellulosic biorefinery processes the production of biofuels and bio-based materials. In the present study, organosolv hardwood and wheat straw lignins were converted in a supercritical fluid consisting of carbon dioxide/acetone/water (300-370°C, 100bar) to a phenolic oil consisting of oligomeric fragments and monomeric aromatic compounds with a total yield of 10-12% based on lignin. These yields are similar to the state-of-the-art technologies such as base-catalysed thermal processes applied for lignin depolymerisation. Addition of formic acid increases the yield of monomeric aromatic species by stabilizing aromatic radicals. Supercritical depolymerisation of wheat straw and hardwood lignin yielded monomeric compounds in different compositions with a maximum yield of 2.0% for syringic acid and 3.6% for syringol, respectively. The results of the present study showed that under the applied conditions competition occurred between lignin depolymerisation and recondensation of fragments.
木质素的增值在木质纤维素生物炼制过程中生物燃料和生物基材料的进一步发展中起着关键作用。在本研究中，有机溶剂硬木和小麦秸秆木质素在由二氧化碳/丙酮/水（300-370°C，100bar）组成的超临界流体中转化为酚油，其中含有低聚片段和单体芳香族化合物，基于木质素的总收率为 10-12%。这些收率与最先进的技术相似，例如应用于木质素解聚的碱性催化热过程。甲酸的添加通过稳定芳基自由基增加了单体芳香族物质的产率。小麦秸秆和硬木木质素的超临界解聚分别以 2.0%的丁香酸和 3.6%的丁香醇为最大产率，生成了不同组成的单体化合物。本研究的结果表明，在所应用的条件下，木质素解聚和碎片再缩合之间存在竞争。
