Electrochemical Grignard Reagent Synthesis for Ionic‐Liquid‐Based Magnesium–Air Batteries

Abstract

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 1H nuclear 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.

Current Progress on Rechargeable Magnesium–Air Battery

“…For the electrolyte, much research of ionic liquids as useful additives took place from 2011 to 2014 in order to obtain high anode potentials and energy densities . In addition, chitosan−choline nitrate (CS−[Ch][NO 3 ]) thin–film polymer electrolytes have been found to deliver a high ionic conductivity of 8.9 × 10 −3 S cm −1 and a volumetric power density of 3.9 W L −1 for Mg–air cells .…”

Uji fotokatalisis reduksi benzaldehida menggunakan titanium dioksida hasil sintesis

“…Sintesis senyawa organik pada umumnya melewati tahapan yang cukup panjang dan menggunakan pelarut yang berbahaya. Pelarut yang biasa digunakan pada sintesis senyawa organik pada umumnya adalah tetrahidrofuran (THF) atau dietil eter, namun pelarut THF cukup berbahaya karena cenderung akan membentuk peroksida jika disimpan dalam udara sehingga mudah meledak dan dietil eter yang bersifat toksik (Luder & Ein-Eli, 2014). Jika menggunakan titanium dioksida sebagai fotokatalis, muatan-muatan yang terdapat pada senyawa organik yang akan disintesis akan mengalami reduksi dan oksidasi pada pita valensi, yang dapat mengurai air (H 2 O) menjadi gas H 2 dan gas O 2 dan tidak menggunakan pelarut berbahaya sehingga lebih ramah lingkungan (Hoffman, 2015).…”

Electrochemical CO2 Fixation to α-Methylbenzyl Bromide in Divided Cells with Nonsacrificial Anodes and Aqueous Anolytes

“…However, R − can also uptake Mg 2+ ion to form a Grignard reagent 25,26 that selectively reacts with CO 2 , producing a corresponding carboxylate with quantitative yields 27 (Scheme 1, pathway II). In fact, the formation of Grignard reagents from organic halides in electrochemical cells with Mg anodes has been observed in the absence of CO 2 .…”

“…However, R – can also uptake Mg 2+ ion to form a Grignard reagent , that selectively reacts with CO 2 , producing a corresponding carboxylate with quantitative yields (Scheme , pathway II). In fact, the formation of Grignard reagents from organic halides in electrochemical cells with Mg anodes has been observed in the absence of CO 2 . , Moreover, the majority of reported EC of R–X was performed at constant current conditions, − ,− resulting in inevitable large potential fluctuations .…”

“…However, R – can also uptake Mg 2+ ion to form a Grignard reagent , that selectively reacts with CO 2 , producing a corresponding carboxylate with quantitative yields (Scheme , pathway II). In fact, the formation of Grignard reagents from organic halides in electrochemical cells with Mg anodes has been observed in the absence of CO 2 . , Moreover, the majority of reported EC of R–X was performed at constant current conditions, − ,− resulting in inevitable large potential fluctuations . Consequently, at high negative potentials, the reduction of Mg 2+ to Mg 0 [ E ° = −2.38 V vs standard hydrogen electrode (SHE)] at the cathode could also facilitate the Grignard reagent formation (Scheme , pathway III), in addition to enabling competing CO 2 electroreduction .…”