Organic Electrosynthesis - Fundamentals and Applications of Organic Electrochemistry - page 199

In the case of the SPE electrolysis system in
which an electrode is pressed onto only a single
side of the surface of an ion-exchange
membrane, the counter-electrode chamber is
filled with electrolytic solvent. In SPE systems,
even non-polar solvents like hexane can be used
as electrolytic solvents. Furthermore, when the
starting substrate is a liquid or gas, electrolysis
can be performed without any solvents.
Moreover, the amount of redox mediator used
can be reduced by immobilizing it on the SPE
composite electrode.
Various organic electrosyntheses using SPE
systems have been reported to date, e.g.
hydrogenation of olefins, reduction of
nitrobenzene, Kolbe electrolysis,
dimethoxylation of furan and ketone synthesis
using a halogen mediator, etc. [2-4]. SPE
electrosynthesis is an energy-efficient
electrolytic method since the cell voltage is low
owing to the small distance between electrodes.
However, the durability of SPE composite
electrodes is not high and contamination of the
SPE membrane decreases the current efficiency
and yield. Those problems have not yet been
solved and a commercialized SPE organic
electrosynthesis has not been established to
date. The original concept for SPE organic
electrosynthesis is a polymer electrolyte fuel cell
(PEFC). Thus, the development of new
materials such as membranes and increased