Electrocatalytic Upgrading of Phenolic Compounds Observed after Lignin Pyrolysis
Electrocatalytic Upgrading of Phenolic Compounds Observed after Lignin Pyrolysis
复制标题
DOI：
10.1021/acssuschemeng.9b00019
复制
发表时间：
2019-05-06
影响因子：
8.4
通讯作者：
Saffron, Christopher M.
中科院分区：
文献类型：
--
作者：
Garedew, Mahlet;Young-Farhat, Daniel;Saffron, Christopher M.
随着生物质分馏方法达到更高的技术成熟水平，木质素价值的提高越来越重要。一种升级木质素的方法首先涉及通过快速热解对其进行解构以产生木质素衍生的生物油。富含酚类化合物的液体产物是用于电催化氢化的有前景的原料，因为芳烃可以通过催化阴极上化学吸附的氢脱氧和饱和，从而减轻产物的腐蚀性并提高其能量含量。通过将生物质分馏与热解解构和电催化升级相结合，木质素可以被增值为燃料和化学品，从而显着提高生物炼制的盈利能力。在这项研究中，代表木质素生物油组分的模型化合物在温和的温度下使用活性炭布上的钌进行电催化氢化（ECH）。研究了苯酚、愈创木酚、姜子酚以及几种相关的烷基酚和芳基甲基醚。除了氢化，还观察到C-O和C-C氢解。烷基酚的转化率随着烷基链长度的增加而降低。类似地，对于烷基取代的愈创木酚，转化率随着烷基链长度的增加而降低，并且选择性远离脱甲氧基化，有利于烷基取代的2-甲氧基环己醇。增加底物浓度提高了法拉第效率，在较高浓度下达到平台。通过绘制出木质素相关底物的电催化条件和反应性，这项工作进一步打开了通过热解-电催化途径将生物质升级为燃料和化学品的希望之门。
Lignin valorization is increasingly important as biomass fractionation approaches achieve higher technology readiness levels. One approach to upgrade lignin first involves its deconstruction by fast pyrolysis to create a lignin-derived bio-oil. The phenolics-rich liquid product is a promising feedstock for electrocatalytic hydrogenation, as aromatics can be deoxygenated and saturated by hydrogen chemisorbed on catalytic cathodes, mitigating the product's corrosivity and raising its energy content. By integrating biomass fractionation with pyrolytic deconstruction and electrocatalytic upgrading, lignin can be valorized to fuels and chemicals that significantly enhance the profitability of biorefineries. In this study, model compounds representing lignin bio-oil components were subjected to electrocatalytic hydrogenation (ECH) at mild temperatures using ruthenium on activated carbon cloth. Phenol, guaiacol, syringol, and several related alkyl phenols and aryl methyl ethers were studied. In addition to hydrogenation, C-O and C-C hydrogenolysis were observed. Conversion of the alkyl phenols decreased with increasing alkyl chain length. Similarly, for alkyl-substituted guaiacols, conversion decreased as alkyl chain length increased, and selectivity shifted away from demethoxylation, favoring alkyl-substituted 2-methoxycyclohexanol. Increasing substrate concentration improved the Faradaic efficiency up to a plateau at higher concentrations. By mapping out electrocatalytic conditions and reactivities of lignin-relevant substrates, this work further opens the door to the promise of biomass upgrading to fuels and chemicals via the pyrolysis-electrocatalysis pathway.