Grignard reagents with metallic anodes

The reaction occurs at lead anodes at the cathode metallic magnesium is produced. An ether solution of the Grignard reagent is used to which ethyl chloride is added. The latter reacts with the magnesium that is formed, to regenerate part of the Grignard reagent consumed. The overall reaction in the electrolyzer follows the equation... 

Due to the difference in the atomic structure of Mg and Ca, it is impossible to form Grignard-type reagents with Ca (all the bonds of this metal are ionic in nature). Consequently, it is impossible to regard Ca as a potential anode material in rechargeable batteries, and hence, the interest in Ca/organic electrolyte systems is limited. 

Many organic ions are stable only in organic solvents, in particular aprotic media. Thus the oxidation of Grignard reagents and of the alkyls and aryls of alkali metals can be conducted only in ethers. The field has been reviewed by several authors. " The products are characteristic of radical intermediates, hydrocarbons being formed by disproportionation and dimerisation reactions and metal alkyls by reaction of the radicals with the anode material when anodes of lead, cadmium, zinc or aluminium are employed. 

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