Skip to main content

Research Repository

Advanced Search

Multiphase Methods in Organic Electrosynthesis

Marken, Frank; Wadhawan, Jay D.


Frank Marken



© 2019 American Chemical Society. ConspectusWith water providing a highly favored solution environment for industrial processes (and in biological processes), it is interesting to develop water-based electrolysis processes for the synthesis and conversion of organic and biomass-based molecules. Molecules with low solubility in aqueous media can be dispersed/solubilized (i) by physical dispersion tools (e.g., milling, power ultrasound, or high-shear ultraturrax processing), (ii) in some cases by pressurization/supersaturation (e.g., for gases), (iii) by adding cosolvents or "carriers" such as chremophor EL, or (iv) by adding surfactants to generate micelles, microemulsions, and/or stabilized biphasic conditions. This Account examines and compares methodologies to bring the dispersed or multiphase system into contact with an electrode. Both the microscopic process based on individual particle impact and the overall electro-organic transformation are of interest. Distinct mechanistic cases for multiphase redox processes are considered.Most traditional electro-organic transformations are performed in homogeneous solution with reagents, products, electrolyte, and possibly mediators or redox catalysts all in the same (usually organic) solution phase. This may lead to challenges in the product separation step and in the reuse of solvents and electrolytes. When aqueous electrolyte media are used, reagents and products (or even the electrolyte) may be present as microdroplets or nanoparticles. Redox transformations then occur during interfacial "collisions" under multiphase conditions or within a reaction layer when a redox mediator is present. Benefits of this approach can be (i) the use of a highly conducting aqueous electrolyte, (ii) simple separation of products and reuse of the electrolyte, (iii) phase-transfer conditions in redox catalysis, (iv) new reaction pathways, and (v) improved sustainability. In some cases, a surface phase or phase boundary processes can lead to interesting changes in reaction pathways. Controlling the reaction zone within the multiphase redox system poses a challenge, and methods based on microchannel flow reactors have been developed to provide a higher degree of control. However, detrimental effects in microchannel systems are also observed, in particular for limited current densities (which can be very low in microchannel multiphase flow) or in the development of technical solutions for scale-up of multiphase redox transformations.This Account describes physical approaches (and reactor designs) to bring multiphase redox systems into effective contact with the electrode surface as well as cases of important electro-organic multiphase transformations. Mechanistic cases considered are "impacts" by microdroplets or particles at the electrode, effects of dissolved intermediates or redox mediators, and effects of dissolved redox catalysts. These mechanistic cases are discussed for important multiphase transformations for gaseous, liquid, and solid dispersed phases. Processes based on mesoporous membranes and hydrogen-permeable palladium membranes are discussed.


Marken, F., & Wadhawan, J. D. (2019). Multiphase Methods in Organic Electrosynthesis. Accounts of chemical research, 52(12), 3325-3338.

Journal Article Type Article
Acceptance Date Nov 14, 2019
Online Publication Date Nov 25, 2019
Publication Date Dec 17, 2019
Deposit Date Nov 14, 2019
Publicly Available Date Oct 27, 2022
Journal Accounts of Chemical Research
Print ISSN 0001-4842
Electronic ISSN 1520-4898
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 52
Issue 12
Pages 3325-3338
Keywords Redox reactions; Electrosynthesis; Electrodes; Electrolysis; Electrolytes
Public URL
Publisher URL


Article (2.2 Mb)

Copyright Statement
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Accounts of Chemical Research, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see

You might also like

Downloadable Citations