Glycerols electrode processes

Several other factors are also responsible for important differences in electrochemical behaviour in different solvent systems. More viscous solvents impede the mass transfer processes, by which reactants are brought to the electrode surface and products are swept away. In such solvents the solution resistivities are high with consequently large heating effects, power wastage and the exacerbation of experimental problems associated with the maintenance of uniform electrical conditions across the electrode surface. However, the choice of viscous solvents such as glycerol or sulpholane is advantageous when diffusion phenomena are under study. Solution resistivity problems also arise when the solvent fails to promote complete dissociation of the electrolyte or permits extensive ion association. 

Over recent years, the question of whether or not surfactants form aggregates similar to micelles, which then form mesophases in other polar solvents, has received considerable attention (196-219). The solvents concerned are polar liquids such as glycerol, ethylene glycol, formamide or ethyl ammonium nitrate (a molten electrolyte at ambient temperature). The answer is YES, but the thermodynamics of the aggregation process is somewhat different. Figures 21.39 and 21.40 show measurements of the EMF from a surfactant-specific electrode in hexadecylpyridinium bromide solutions where water and ethylene glycol are solvents. 

MonoSik, R., Ukropcova, D., Stredansky, M., and Sturdik, E. (2012) Multienzy-matic amperometric biosensor based on gold and nanocomposite planar electrodes for glycerol determination in wine. Anal. Biochem., 421, 256-261. Bruggink, A., Schoevaart, R., and Kieboom, T. (2003) Concepts of nature in organic synthesis cascade catalysis and multistep conversions in concert. Org. Process Res. Dev., 7, 622-640. 

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