Kosuke Izutsu (writer)
Electrochemistry inNonaqueous Solutions
A majority of chemical reactions are carried out in solution. The use of a solvent
as reaction medium makes it easy to control reaction conditions such as tempera-
ture, pressure, pH, rate of mass transfer, and concentration of reactant. Water is
the most popular solvent. However, by using appropriate non-aqueous solvents,
substances that are insoluble in water can be dissolved, substances that are un-
stable in water remain stable, and chemical reactions that are impossible in water
become possible. The reaction environments are markedly wider in non-aqueous
solvents than in water.
The widespread use of non-aqueous solvents, especially dipolar aprotic solvents,
began in the 1950s in various fields of pure and applied chemistry and has con-
tributed greatly to later advances in chemical sciences and technologies. From the
very beginning, electrochemistry in non-aqueous solutions has played an impor-
tant role in exploring new chemical possibilities as well as in providing the meth-
ods to evaluate static solvent effects on various chemical processes. Moreover,
many new electrochemical technologies have been developed using non-aqueous
solvents. Recently, electrochemistry in non-aqueous solutions has made enormous
progress: the dynamic solvent effects on electrochemical processes have been
greatly elucidated and solvent effects are now understood much better than be-
fore. On the other hand, however, it is also true that some useful solvents have
properties that are problematic to human health and the environment. Today, ef-
forts are being made, under the framework of ‘green chemistry’, to find environ-
mentally benign media for chemical processes, including harmless non-aqueous
solvents, immobilized solvents, ionic liquids, supercritical fluids, aqueous sys-
tems, and even solventless reaction systems. For electrochemical purposes, replac-
ing hazardous solvents by harmless solvents, ionic liquids and supercritical fluids
appears to be promising.
This book was written to provide readers with some knowledge of electrochem-
istry in non-aqueous solutions, from its fundamentals to the latest developments,
including the current situation concerning hazardous solvents. The book is di-
vided into two parts. Part I (Chapters 1 to 4) contains a discussion of solvent prop-
erties and then deals with solvent effects on chemical processes such as ion solva-
tion, ion complexation, electrolyte dissociation, acid-base reactions and redox reac-
tions. Such solvent effects are of fundamental importance in understanding chem-
istry in non-aqueous solutions; furthermore, their quantitative evaluations are of-
ten carried out by means of electrochemical techniques. Part II (Chapters 5 to 12)
mainly deals with the use of electrochemical techniques in non-aqueous solu-
tions. In Chapter 5, the fundamentals of various electrochemical techniques are
outlined in preparation for the following chapters. In Chapters 6 to 9, the applica-
tions of potentiometry, conductimetry, polarography, voltammetry, and other new
electrochemical techniques in non-aqueous solutions are discussed by focusing on
the chemical information they provide. Chapters 10 and 11 examine methods of
selecting and purifying the solvents and electrolytes of electrochemical impor-
tance. Finally, in Chapter 12, some practical applications of non-aqueous solvents
in modern electrochemical technologies are discussed. These include their use in
batteries, capacitors and display devices, and such processes as electrolytic refin-
ing, plating, synthesis and polymerization. The applicability of ionic liquids and
supercritical fluids as environmentally benign media for electrochemical technol-
ogy is also dealt with.
Most chemists are familiar with chemistry in aqueous solutions. However, the
common sense in aqueous solutions is not always valid in non-aqueous solutions.
This is also true for electrochemical measurements. Thus, in this book, special
emphasis is placed on showing which aspects of chemistry in non-aqueous solu-
tions are different from chemistry in aqueous solutions. Emphasis is also placed
on showing the differences between electrochemical measurements in non-aque-
ous systems and those in aqueous systems. The importance of electrochemistry in
non-aqueous solutions is now widely recognized by non-electrochemical scientists
– for example, organic and inorganic chemists often use cyclic voltammetry in
aprotic solvents in order to determine redox properties, electronic states, and reac-
tivities of electroactive species, including unstable intermediates. This book will
therefore also be of use to such non-electrochemical scientists.
I obtained most of the information included in this book from the publications
of many scientists in this field. I would like to express my sincere thanks to all of
them. I also would like to thank my coworkers for their cooperation, the editorial
and production staff of Wiley-VCH for their help and support, and my wife for
her assistance and patience.[ Last edited by 战国时代 on 2012-1-3 at 18:04 ] |