Department of Chemistry, Boston College, Merkert Chemistry Center, 2609 Beacon St., Chestnut Hill, MA, 02467, USA.
Angew Chem Int Ed Engl. 2021 Mar 29;60(14):7534-7539. doi: 10.1002/anie.202016601. Epub 2021 Feb 24.
We report an electrochemical method for coupling biomass-derived C5/C6 compounds to value-added fuel precursors. Using only 2 % of equivalent charges, 2-methylfuran (2-MF) was oxidized to yield a cation radical, which readily reacted with 3-hexene-2,5-dione, a derivate of 2,5-dimethylfuran, to produce 3-(5-methylfuran-2-yl)hexane-2,5-dione. The product was converted to 4-ethylnonane (a component of biodiesel/jet fuel) in a single step in excellent yield. Importantly, the reaction was not sensitive to oxygen, and a trace amount of water was found to promote the reaction. Detailed mechanistic studies confirmed the proposed reaction pathways. Key to the mechanism is the radical generation that is enabled by electrochemistry. The radical is regenerated at the end of a reaction cycle to ensure chain propagation for an average of ca. 47 times, resulting in an apparent Faradaic efficiency of 4700 %.
我们报告了一种电化学方法，用于将生物质衍生的 C5/C6 化合物偶联到增值燃料前体上。仅使用 2%的当量电荷，2-甲基呋喃（2-MF）被氧化生成阳离子自由基，该自由基可与 3-己烯-2,5-二酮（2,5-二甲基呋喃的衍生物）快速反应，生成 3-(5-甲基呋喃-2-基)己烷-2,5-二酮。该产物在一步反应中以优异的收率转化为 4-乙基壬烷（生物柴油/喷气燃料的组成部分）。重要的是，该反应对氧气不敏感，并且发现痕量的水可促进反应。详细的机理研究证实了所提出的反应途径。该机理的关键是电化学产生的自由基生成。自由基在反应循环结束时再生，以确保平均约 47 次的链延伸，从而导致表观法拉第效率为 4700%。
