Instituto de Tecnología Química, Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022, Valencia, Spain.
Técnicas Reunidas, José Lladó Technology Centre Proprietary Technology Development Division, C/Sierra Nevada n° 16, 28830, San Fernando de Henares, Spain.
ChemSusChem. 2020 Sep 7;13(17):4743-4758. doi: 10.1002/cssc.202001295. Epub 2020 Aug 19.
During oxidative depolymerization of lignin in aqueous alkaline medium using molecular oxygen as oxidant, the highly functionalized primary phenolic monomers are not stable products, owing to various not fully identified secondary reaction mechanisms. However, better understanding of the mechanisms responsible for the instability of the main part of the products of interest derived from lignin is of much interest. Evaluation of their individual reactivities under oxidative conditions should significantly help to find a better way to valorize the lignin polymer and to maximize the yields of target value-added products. Consequently, the main objective of this study is to assess the individual stabilities of some selected lignin-based phenolic compounds, such as vanillin, vanillic acid, and acetovanillone, together with some other pure chemical compounds such as phenol and anisole to give an insight into the mechanisms responsible for the simultaneous formation and repolymerization of those products and the influence of the oxidation conditions. Various complementary strategies of stabilization are proposed, discussed, and applied for the oxidative depolymerization reactions of a technical lignin extracted from pinewood with a high content of β-O-4 interconnecting bonds to try to obtain enhanced yields of value-added products.
在使用分子氧作为氧化剂的木质素在碱性水介质中的氧化解聚过程中，由于各种未完全确定的次级反应机制，高官能化的初级酚单体不是稳定的产物。然而，更好地了解导致木质素衍生的主要产物部分不稳定的机制非常重要。评估它们在氧化条件下的单独反应性应有助于找到更好的方法来利用木质素聚合物并最大限度地提高目标增值产品的产率。因此，本研究的主要目的是评估一些选定的木质素基酚类化合物（如香草醛、香草酸和乙酰香草酮）以及一些其他纯化学化合物（如苯酚和苯甲醚）的单独稳定性，以深入了解导致这些产物同时形成和重聚合的机制以及氧化条件的影响。提出、讨论并应用了各种互补的稳定策略，用于从松木中提取的高β-O-4 键连接含量的技术木质素的氧化解聚反应，以尝试获得更高产率的增值产品。
