Electrochemical synthesis potentiostatic

One of the most important, yet latent, applications of controlled-potential electrolysis is electrochemical synthesis. Although electrolysis has been used for more than a century to synthesize various metals from their salts, application to other types of chemical synthesis has been extremely limited. Before the advent of controlled-potential methods, the selectivity possible by classical electrolysis precluded fine control of the products. The only control was provided by appropriate selection of electrode material, solution acidity, and supporting electrolyte. By these means the effective electrode potential could be limited to minimize the electrolysis of the supporting electrolyte or the solvent. Today potentiostats and related controlled-potential-electrolysis instrumentation are commercially available that provide effective control of the potential of the working electrode to 1 mV, and a driving force of up to 100 V for currents of up to several amperes. Through such instrumentation electrochemical syn-... 

Conjugated polymers can often also be synthesized using a chemical oxidative polymerization. Distinct advantages of the chemical route over electrochemical synthesis are that there is no need for electrochemical instruments such as a potentiostat and that also nonconductive siufaces can be coated. Moreover, chemical polymerization is known to be simple and fast mefliod and strongly recommended if... 

Apparatus and materials. All electrochemical polymerizations, amperometric measurements and cyclic voltammetry were carried out with an EG G Princeton Applied Research Potentiostat model 273. Pyrrole was purified by vacuum distillation and by passage over neutral alumina prior to electropolymerization. The polyanions (1) used as dopants are shown in Figure 1, and were purified twice by precipitation from methanol in 0.1 M HC1. Detailed information about their synthesis and catalytic... 

It is much easier to produce the correct energy level for the receipt of electrons from a reactant into the electrode in an anodic synthesis than to arrange for effective electron transfer in a homogeneous solution. In the electrochemical method, one calmly adjusts the potentiostat setting in a solution that may be near room temperature. In solution, one has to worry about adjusting reactants and products—probably catalysts—until it works. And it may be that the chemical reaction won t work at a significant rate until the temperature is raised. 

Very many types of organic synthesis can now be carried out electrochemically, often more advantageously than by other means. Organic electrosynthesis, always multi-disciplinary, now includes photoelectrochemistry, electro-catalysis, bioelectrochemistry and others. Some of the scientific and technological developments which led to the present status of the field will be cited the use of potential control, the invention of the potentiostat, the combination of electrochemistry with spectroscopy, the use of ion-selective membranes the large-scale production of sorbitol, adiponitrile, and dimethyl sebacate. 

The substitution at the 3-position has been preferred by Gar-nier and co-workers, owing to the excellent conducting properties of the resulting polypyrrole films. Accordingly, they have reported the synthesis and the electrochemical behavior of a new polypyrrole 3-substituted by a polyether chain [255]. 3-(3,6-Dioxaheptyl)pyrrole (8a) was potentiostatically electropolymer-ized, whereas the electrooxidation of 8b did not give rise to a polymer film because of the steric effect caused by the substituents. 

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