Advanced Model Compounds for Understanding Acid-Catalyzed Lignin Depolymerization: Identification of Renewable Aromatics and a Lignin-Derived Solvent
Advanced Model Compounds for Understanding Acid-Catalyzed Lignin Depolymerization: Identification of Renewable Aromatics and a Lignin-Derived Solvent
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DOI：
10.1021/jacs.6b04144
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发表时间：
2016-07-20
影响因子：
15
通讯作者：
Barta, Katalin
中科院分区：
文献类型：
--
作者：
Lahive, Ciaran W.;Deuss, Peter J.;Barta, Katalin
这种芳香族生物聚合物的复杂性挑战了木质素解聚的根本性新方法的开发。虽然过于简化的模型化合物往往缺乏相关性的化学木质素，直接使用木质素流提出了重大的分析挑战，方法的发展。理想情况下，新方法应该在模型化合物上进行测试，这些模型化合物足够复杂，可以反映木质素的结构多样性，但分子量仍然足够低，可以进行简单的分析。在这方面的贡献，我们提出了一类新的先进的（β-O-4）-（β-5）的双连接模型，是高度现实的代表性的木质素片段。连同选定的β-O-4、β-5和β-β结构，这些化合物提供了对酸催化中各种类型的木质素键的反应性以及使用乙二醇稳定反应性中间体的详细理解。这些新模型的使用允许识别新的反应途径和中间体，并导致在随后的木质素解聚研究中的新的二聚体产物的表征。模型和木质素实验之间的良好相关性突出了这类新的模型化合物在催化研究中更广泛使用的相关性。只有通过在这个细节水平上理解木质素中的键的反应性，才能开发出完全优化的木质素解聚策略。
The development of fundamentally new approaches for lignin depolymerization is challenged by the complexity of this aromatic biopolymer. While overly simplified model compounds often lack relevance to the chemistry of lignin, the direct use of lignin streams poses significant analytical challenges to methodology development. Ideally, new methods should be tested on model compounds that are complex enough to mirror the structural diversity in lignin but still of sufficiently low molecular weight to enable facile analysis. In this contribution, we present a new class of advanced (beta-O-4)-(beta-5) dilinkage models that are highly realistic representations of a lignin fragment. Together with selected beta-O-4, beta-5, and beta-beta structures, these compounds provide a detailed understanding of the reactivity of various types of lignin linkages in acid catalysis in conjunction with stabilization of reactive intermediates using ethylene glycol. The use of these new models has allowed for identification of novel reaction pathways and intermediates and led to the characterization of new dimeric products in subsequent lignin depolymerization studies. The excellent correlation between model and lignin experiments highlights the relevance of this new class of model compounds for broader use in catalysis studies. Only by understanding the reactivity of the linkages in lignin at this level of detail can fully optimized lignin depolymerization strategies be developed.