Revealing the fate of the phenylcoumaran linkage during lignin oxidation reactions
Revealing the fate of the phenylcoumaran linkage during lignin oxidation reactions
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DOI：
10.1039/c7ob03087h
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发表时间：
2018-03-21
影响因子：
3.2
通讯作者：
Westwood, Nicholas J.
中科院分区：
文献类型：
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作者：
Lahive, Ciaran W.;Lancefield, Christopher S.;Westwood, Nicholas J.
除了-O-4外，大多数木质素键在选择性氧化条件下的命运在很大程度上是未知的。在这项工作中，我们使用先进的-5木质素模型化合物来确定在DDQ氧化过程中软木木质素中苯基香豆素单位的命运。通过使用模型化合物结合使用HSQC和HMBC NMR对氧化木质素聚合物的详细表征，我们表明苯香豆酮是氧化木质素的主要产物，因此在氧化木质素中构成了一种新的非天然-5键。此外，这些单位在木质素中的反应性使我们进一步研究了它们在木质素中的连通性，表明它们既可以作为酚化单位，也可以作为醚化单位。本研究的发现和方法将有助于提高选择性氧化木质素解聚过程的效率，特别是那些旨在升级软木木质素的过程，其中苯香豆素是主要的连锁反应。
The fate of most lignin linkages, other than the -O-4, under selective oxidation conditions is largely unknown. In this work we use advanced -5 lignin model compounds to identify the fate of phenylcoumaran units in a softwood lignin during oxidation with DDQ. By using model compounds combined with detailed characterisation of the oxidised lignin polymer using HSQC and HMBC NMR we show that phenylcoumarones are a major product, and therefore constitute a novel non-native -5 linkage in oxidised lignins. Additionally, the reactivity of these units in lignin led us to further investigate their connectivity in lignin, showing that they are found as both phenolic and etherified units. The findings and approach developed here will help improve the efficiency of selective oxidative lignin depolymerisation processes, particularly those aimed at the upgrading of softwood lignin in which phenylcoumarans are a major linkage.