Institute of Bioanalytical Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany.
Institute of Physical Chemistry, Saarland University, Campus B2.2, 66123, Saarbrücken, Germany.
Sci Rep. 2017 Jul 11;7(1):5041. doi: 10.1038/s41598-017-05316-x.
Lignin's aromatic building blocks provide a chemical resource that is, in theory, ideal for substitution of aromatic petrochemicals. Moreover, degradation and valorization of lignin has the potential to generate many high-value chemicals for technical applications. In this study, electrochemical degradation of alkali and Organosolv lignin was performed using the ionic liquids 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and triethylammonium methanesulfonate. The extensive degradation of the investigated lignins with simultaneous almost full recovery of the electrolyte materials provided a sustainable alternative to more common lignin degradation processes. We demonstrate here that both the presence (and the absence) of water during electrolysis and proton transport reactions had significant impact on the degradation efficiency. Hydrogen peroxide radical formation promoted certain electrochemical mechanisms in electrolyte systems "contaminated" with water and increased yields of low molecular weight products significantly. The proposed mechanisms were tentatively confirmed by determining product distributions using a combination of liquid chromatography-mass spectrometry and gas-chromatography-mass spectrometry, allowing measurement of both polar versus non-polar as well as volatile versus non-volatile components in the mixtures.
木质素的芳族结构单元提供了一种化学资源，理论上可以替代芳烃石油化工产品。此外，木质素的降解和增值有潜力产生许多用于技术应用的高价值化学品。在这项研究中，使用离子液体 1-乙基-3-甲基咪唑三氟甲烷磺酸盐和三乙铵甲烷磺酸盐对碱木质素和有机溶剂木质素进行了电化学降解。所研究的木质素被广泛降解，同时电解质材料几乎完全回收，为更常见的木质素降解工艺提供了可持续的替代方案。我们在这里证明，在电解过程中以及质子迁移反应中是否存在水对降解效率有重大影响。在“污染”有水的电解质体系中，过氧化氢自由基的形成促进了某些电化学机制，显著提高了低分子量产物的产率。通过使用液相色谱-质谱联用和气相色谱-质谱联用相结合的方法来确定产物分布，对提出的机制进行了初步验证，从而可以测量混合物中极性与非极性以及挥发性与非挥发性成分。
