Electrochemical Grignard Reagent Synthesis for Ionic-Liquid-Based Magnesium-Air Batteries

Metal-organic compounds are widely used in the production of fine chemicals and pharmaceutical agents. On large scales, the chemical production of Grignard reagents (GRs) with ether solvents is difficult. The electrochemical synthesis of GRs in ionic-liquid-based electrolytes is reported herein. The electrochemical synthesis and presence of the GR product are demonstrated by cyclic voltammetry and ¹Hnuclear magnetic resonance spectroscopy and by comparing the measured passing charge to the final GR concentration. Additionally, the high-boiling ether tetraethylene glycol dimethyl ether is shown to be a suitable substitute for volatile tetrahydrofuran ether, which is currently used. A mechanism for the electrochemical synthesis of the GR is suggested and discussed, and the potential importance of the process for high-energy-density applications is demonstrated with a magnesium-air cell. Electropolishing of the Mg anode is also observed and discussed.