Electrochemical synthesis pathways hold the potential to dramatically reduce the carbon footprint of the chemical industry by replacing heat from fossil fuel combustion with renewable electricity as the driving force for reactions. However, the electrification of reactions involving organic compounds has received little attention as the reactivity of small inorganic molecules, such as CO2, N2 and H2O, has dominated recent efforts. Herein, we present approaches to activate C-H and C-C bonds in small organic molecules to facilitate more complex reactivities. These approaches include a chloride-mediated pathway to enable C(sp3)-H bond activation and the real-time control of alkane reactivity through changes to the applied potential. The partial oxidation of ethanol to form ethylene oxide is achieved using a chloride mediated pathway, in which ethanol is first chlorinated to 2-chloroethanol before undergoing an internal cyclization under alkaline conditions to form the epoxide. The formation of 2-chloroethanol hinges on a key selectivity challenge, as it requires chlorination at the β-carbon while suppressing the thermodynamically more favorable chlorination at the α-carbon. Our experiments show that the selectivity to 2-chloroethanol is significantly impacted by the temperature and applied potential in a manner consistent with a mechanism governed by an initial hydrogen atom transfer from ethanol. The role of the applied potential in organic molecule transformation is further shown in the electrocatalytic transformation of unactivated alkanes at room temperature. Using real-time modification of the electrode potential we demonstrate control over ethane adsorption, surface transformation, and product desorption. Potential modification provides control over the conversion of catalytic alkane intermediates while they are bound to an electrocatalyst surface and represents a significant advancement in controlling catalytic reactions.

Electrocatalytic transformation of C(sp3)-H and C(sp3)-C(sp3) bonds in small organic molecules

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