Science of Synthesis

Villani, E.; Inagi, S., Science of Synthesis: Electrochemistry in Organic Synthesis, (2021) 1, 156.

To explain the theory of bipolar electrochemistry, one should consider the following example where a conducting object (any material composed of metal, carbon, conductive metal oxides, etc.) is placed in an electrolytic solution in between two feeder electrodes (collectors). In a solution containing a low concentration of supporting electrolyte, electrical double layers at the electrode/solution interface are poorly formed; instead, the generation of an electric field extending into the bulk solution is expected when a potential difference is applied between the feeder electrodes. As a consequence, and due to the fact that the conducting object can be considered as equipotential, individual anodic and cathodic overpotentials can be established at every point of the object, with opposite polarization respective to the polarization of the feeder electrode; for example, the side of the object facing the feeder anode will become cathodic and vice versa. When electroactive species, red1 and ox2, are present in the electrolytic solution, electrochemical reactions can occur at the opposite sides of the object as shown in the equations in ‌Figure 3‌, where n1 and n2 are the number of electrons involved in each electrochemical process, red1/ox1 and ox2/red2 are the two redox couples, and E1° and E2° the standard potentials of each reaction.

‌Meeeee 8‌

Me eeeeeee eee eeeeeeeeeeeeeee eeeeeeeee ee eee eeeeeeeeee eeeeee, eee eeeeeee eeeeeeeee eeeeeeeeee (ΔMeee) eee ee ee, eeeeeeeeeeeee, ee eeeee eeeee ee eee eeeeeeeeee ee eee eeeeeeee eeeeeeeeee ee eee eee eeeeeeee eeeee eeeeeee, ee eeeee ee ‌Meeeee 8‌.

‌Meeeee 8‌

Me eeeeeeee eee eeeeeeeeeeeeeeeee ee eee eeeeee, eeeee eee eeeee eeeeeeeee eeeee eeeeeeeeeeeeee ee eee eee eeeeeeee eeeee ee eee eeeeeeeeee eeeeee: eeee eeeeeee eeeeeee eee eeee eeeeeee eeeeeeeee (MMM) ee eee eeeeeeeeee eeeeee. Meeeeee, eee eeeeeeeee eeeeeeeeee eeeeeeeeee ee eee eeee eeeeeeee eeeeeee eee eee eeeeee eeeeeeeeee ee eee eeeeeeee, eee eeeeeee eeeeee eeeeeeee eeeeeee eeee eee ee eee eeeeeeee ee eee eeeeeeee eeeee. Meeeeeeeeeee, eee eeeeee eee eeeeeeee eeeeeeeeeeeeee, ηee eee ηeee, eeeeeeeeeeee (‌Meeeee 8‌), ee eee MMM eeee eeee eeeee eee eeeeee, eeeeeeeeeeee e eeeeeeeee eeeeeeee eeeeeeeeeeee ee eee eeeeeee (‌Meeeee 8‌, e). Meee eeeeeeeee eeeeeee ee eeeeeee eeeeeeeeeeeeeeee ee eeeeeeeee, eee eeeeeee, eee eee eeeeeeeeeee ee eeeeeeee eeeeeeee.[‌8‌] Meeeeeeeeee, eee eeeeeeee ee eee eeeeeeee eeeee eeee eeeeeeee eee eeeeeeeeeeeeeee ee eeeeeee eeeeeee eeee eeee eee eeeeeeeee eeee eeeeeeeeeeee eeeeeeeee ee eee MMM. Mee eeeeeee eeeeeee eeeeeeeeeeee eee eeeeeeeeeeeeeee eee eeee eeee eeeeeeeee eee eee eeeeeeeeeee eeeeee ee eeeee eeeeeeeeee eeeeeeeee (eee Meeeeeee ‌8.8.8‌ eee ‌8.8.8‌ eee eeeeeee eeeeeee).[‌88‌]

Me eeee eeeeeeeeee eeeeeeeeeee, ee eeee eee eeeee eeee eeeeeee eeeee eeeeeeeeee eeee eeeeeeee eeeeee eee eeeeeeeee eeeeeeeeeeee eee eeeeeeeee ee eee MMMʼe eeeeeee, eeee ee eee eeee eeeeeeee, eee eeeeeeee eeeeeee eee eeeeeee, eee eeeeee eee eeeeeeee ee eee MMM, eee eeeeeeeeeeee eeeeeeeeeeee; eeee ee eeeeeeeee ee eeeeee ee eeeeeee eeeeeeeeeee eeeeeee.[‌8‌,‌88‌]

‌Meeeee 8‌ Meeeeee Meeeeeeeeeeeeee Meee eee e Meeeeee Meeeeeeeee, eee Meeeeeeee Meeeeeee Meee Meeeee eee Meeeeeeeeeee Meeeeeee eeeee eee Meeeeeeee ee ee Meeeeeee Meeeeeee Meeee[‌8‌]

Meee ee eee eeeee eeeeeee eeeeeeeee eeeeeee eeeeeee; eee eeeee eee ee eee MMM; eee e8 ee eee eeeeeee eeeeeeee ee eee MMM. Meeeeeeeee eeee eeeeeeeeeeeee eeee (Meeeeee; Meeee; Meeee; Meeeee, Meeeeeeeee Meeeee Meeeeeeeeeeee Meeeeee, Mee. 88), Meeeeeeee (8888), e 88 888 eeee eeeeeeeeee eeee Meee Meeee eee Meee.

Mee eeeee eeeeeeeeeee ee eee eeeeee ee eeeeeee eeeeeeeeeeeeeeee ee eee e eeeeeee eeeeee eeee eeee ee “eeee eeeeeeeeeeeee”. Meee eeee eeeee eeee eee MMM ee eee eeeeeeeeee eeeeeeeeeee eee eeeeeeeeeeeeeee eeee, eeee eeeeeeee eee eeeeeeeeeee ee ee ee eeeee eeeeeee eeeeeee eee eee eeeeee eeeeeeeeee. Me eeee eeeeeeeee, eeeee eee eeeeeeeeee eeeeeee eeeee eeeee eeeeeee eee eeeeeeeeeee eee eee MMM, eeeeeeeeeeee. Meeeeeee, eee eeeeeeeeeee ee ee eeeeeeee eeeeee ee eeeee eeee eeeeeeeee eeeeeeeee ee eeeeeeeeeeeee ee eee eeee MMM eeee eee eeeeeeeeeee ee eeee eeeeee eeeeee eeeeeeeeeee.

Me eeeeeeee, eee “eeeeee eeeeeeeeeeeee” eeeeeeeeee e eeeeeee eeee. Mee eeee eeeeeeeeeee ee eee eeeeeeeee ee eeeee eee MMM ee eeeeeee eeeeeeeeeee eee eeee ee eeee e eee eeee ee ee eeeeeee eeee eee eeeeeeeeeee eeeeeeeeeeee. Me eeee eeee, eee eeee eeeeeee eeee eeeeeeeee ee eeeeeee eee MMM. Meee eeeeeeeeeeeee eee ee eeee ee eeeeeeeeee eeeeeeee eee eeeeeeee eeeeee eeee eee eeeeeeeee eeee, ee ee ee eeeeeeeee ee eeeeeee eee eeeeeeee eeeeeeee ee eeeeeeeee eee eeeeeeeeeeeee eeeeeee, ee eee eeeee eee eeee ee eee MMM ee e eeeeeeeee eeee ee eeeeeeeeeeeeeee eeeeee eeeeeeeee ee eee eeeee eeee. Mee eeeeeeee, eeeeeeeeeeeeeeee eeeeeeeeeeeeeeeee eee eeee eeeeeeee ee e eeeeeeeee eeeeeeeeee ee eeeeeee eeeeeee eeeeeeeee eee eeeeeee eeeeeeeeeeee.[‌88‌,‌88‌] Mee eeeeeeee ee eeeeeee eeeeeee eeeeeeeee ee eeee eeeeeee, eeeeeeeee eeeeeeeeee eeeeeee eeeeeeee eee eeeeeeeeeeeeee eeeeeeeee, eee ee eeeeeeeeee ee eeee eeeeeee.

References