Electrosynthesis inorganics

Inorganic electrosynthesis in non-aqueous solvents. B. L. Laube and C. D. Schmulbach, Prog. 

Polypyrrole relatives obtained by electrosynthesis in the presence of different small inorganic or organic counter-ions that are interchanged with the electrolyte during electrochemical control of the material. 

Table 5b. Conditions and Choice of Electrodes for the Electrosynthesis of Some Inorganic Compounds [75]...

One more inorganic electrosynthesis, peroxodisulphate production, has been studied [135]. Despite an inevitable side-reaction (oxygen evolution), the current efficiency obtained was as high as 75 %. 

Electrosynthesis — Synthesis performed with the help of -> electrolysis. Electrosynthesis is performed both on laboratory as well as on an industrial scale, and both organic and inorganic compounds are synthesized. In most cases, electrosynthesis affords divided cells, i.e., separation of the -> anolyte and -> catholyte by a -> diaphragm to prevent reactions between the products of the reaction proceeding at the -> anode with those formed at the -> cathode. 

There is a trend toward chiral synthesis [132] the Englehard company is said to have piloted the electrosynthesis of chiral diols. New reactor design for the epoxidation of olefins is under development on a pilot scale [133]. Gas diffusion electrodes, developed for fuel cells and inorganic processes, are finding their first applications in organic electrosynthesis [134—136]. Another area of more than laboratory interest is bioelectrochemistry [137] (see also E. Steckhan, Chapter 27 in this volume). 

Laure, B. L. and Schmulbach, C. D., Inorganic Electrosynthesis in Non-aqueous Solvents. 14... 

The distinction in previous sections of electroanalysis, inorganic electrochemistry (particularly metal systems), and electroorganic synthesis leaves out a number of other electrochemical systems. Ultrasound has been applied to many of these, to interesting effect, and this section concerns a number of such systems. There is, of course, overlap in any attempt at compartmentalization, and here some studies on batteries, electrochemiluminescence, and micellar systems could be considered as contributing to electroanalysis, while other multiphase electrolyses might be considered as electrosynthesis. In addition, most multiphase electrolysis is directed to the destruction of haloorganics and is aimed at waste treatment. There are also one-off applications of ultrasound in electrochemistry, which are collected at the end of this section. 

As intensive studies on the ECPs have been carried out for almost 30 years, a vast knowledge of the methods of preparation and the physico-chemical properties of these materials has accumulated [5-17]. The electrochemistry ofthe ECPs has been systematically and repeatedly reviewed, covering many different and important topics such as electrosynthesis, the elucidation of mechanisms and kinetics of the doping processes in ECPs, the establishment and utilization of structure-property relationships, as well as a great variety of their applications as novel electrochemical systems, and so forth [18-23]. In this chapter, a classification is proposed for electroactive polymers and ion-insertion inorganic hosts, emphasizing the unique feature of ECPs as mixed electronic-ionic conductors. The analysis of thermodynamic and kinetic properties of ECP electrodes presented here is based on a combined consideration of the potential-dependent differential capacitance of the electrode, chemical diffusion coefficients, and the partial conductivities of related electronic and ionic charge carriers. 

Processes that depend critically on these phenomena include energy storage and conversion, corrosion and corrosion control, membrane separations, deposition and etching by electrolytic and plasma processes, electrosynthesis of organic and inorganic chemicals, production and refining of metals, pollution detoxification and recovery, desalination, and many others. 

Electrochemistry is a scientific discipline with a well developed system of theories and quantitative relationships. It has many applications and uses in both fundamental and applied areas of chemistry—in the study of corrosion phenomena, for example, for the study of the mechanisms and kinetics of electrochemical reactions, as a tool for the electrosynthesis of organic and inorganic compounds, and in the solution of quantitative analytical problems. This last area will be emphasized in the next four chapters. 

There are lots of systems, especially for electroplating and electrosynthesis, in which electrodes of the first kind can be used, without any liquid junctions (the example is liquid A1 in AlFs-containing melts). More universal systems for melts of various kinds are a chlorine electrode in equimolar NaCl + KCl melt and Ag/Ag+ electrodes with the range of Ag" " concentrations (0.01-10 mM) corresponding to usual solubility values. Reference electrodes of the second kind can hardly be used in melts because of the high solubility of the majority of inorganic solids. 

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