Electrosynthesis, bulk electrolysis

The formation of crystalline fulleride salts at the electrode occurs when less polar solvents and bulky cations are used for the electrosynthesis. The first fulleride salt was synthesized by Wudl by bulk electrolysis of in o-dichlorobenzene with tetraphenylphosphonium chloride as supporting electrolyte [39, 80]. This black microcrystalline material with the composition (Ph4P )3(Cgg )(Cr)2 exhibits an ESR line with a g-value of 1.9991 and a line width of 45 G at room temperature. Single crystals of the slightly different salts (Ph4P )2(Cgg )(Cr) and (Ph4P )2(C50 )(Br ) could be obtained by electrocrystallization and their crystal structure was determined [82, 83]. Magnetic measurements showed the presence of unpaired spins. 

The general considerations and models employed in electroanalytical bulk electrolysis methods are also often applicable to large-scale and flow electrosynthesis, to galvanic cells, batteries, and fuel cells, and to electroplating. 

An alternative method of bulk electrolysis involves flowing the solution to be electrolyzed continuously through a porous working electrode (38) of large surface area. Flow electrolytic methods can result in high efficiencies and rapid conversions and are especially convenient where large amounts of solution are to be treated. Flow methods are of use in industrial situations (e.g., removal of metals such as copper from waste streams) and have been broadly applied to electrosynthesis, separations, and analysis. 

Bulk electrolysis for the purpose of electrosynthesis or for a coulometric determination of the number of electrons (w) associated with a half-cell reaction of the kind A B + neT (A is the compound being oxidized and B is product, with charges being omitted for simplicity, and n is the overall number of electrons transferred per molecule of A oxidized as determined by coulometry and application of Faraday s Law of electrolysis). 

Typical applications of bulk electrolysis include the determination of n or of the total amount of species present (e.g. by electrogravimetry), small-scale preparative electrosynthesis and electroseparation. In addition, any deviation in the linearity of ln(/(0) vs. t or Q t) vs. i(f) indicates complexity in the reaction mechanism (e.g. coupled reactions). 

---