Electrochemical Capture and Release of Carbon Dioxide Using a Disulfide–Thiocarbonate Redox Cycle

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• 作者：Poonam Singh ; Joseph H. Rheinhardt ; Jarred Z. Olson ; Pilarisetty Tarakeshwar ; Vladimiro Mujica ; Daniel A. Buttry
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：January 25, 2017
• 年：2017
• 卷：139
• 期：3
• 页码：1033-1036
• 全文大小：284K
• ISSN：1520-5126

文摘

We describe a new electrochemical cycle that enables capture and release of carbon dioxide. The capture agent is benzylthiolate (RS^–), generated electrochemically by reduction of benzyldisulfide (RSSR). Reaction of RS^– with CO₂ produces a terminal, sulfur-bound monothiocarbonate, RSCO₂^–, which acts as the CO₂ carrier species, much the same as a carbamate serves as the CO₂ carrier for amine-based capture strategies. Oxidation of the thiocarbonate releases CO₂ and regenerates RSSR. The newly reported S-benzylthiocarbonate (IUPAC name benzylsulfanylformate) is characterized by ¹H and ¹³C NMR, FTIR, and electrochemical analysis. The capture–release cycle is studied in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP TFSI) and dimethylformamide. Quantum chemical calculations give a binding energy of CO₂ to benzyl thiolate of −66.3 kJ mol^–1, consistent with the experimental observation of formation of a stable CO₂ adduct. The data described here represent the first report of electrochemical behavior of a sulfur-bound terminal thiocarbonate.