Oxidation of ferricyanidedation of ferricyanide : An electrochemical study of HCF(III) redox reactions

Abstract: The reversible reduction of hexacyanoferrate(III) to the Fe(II) form is a well-known standard in electrochemistry. It is however reported to be highly dependent on the solvent environment.[i] This electrochemical project has aimed to examine the behaviour of ferricyanide in aprotic environment by changing the solvent to acetonitrile, a medium polar solvent with a high dielectric constant. The method used for research is cyclic voltammetry. Ferricyanide has been examined in aqueous and aprotic solvent and has been studied in comparison to ferrocene, which is a well-known chemical substance. When studying ferricyanide in acetonitrile solvent under inert conditions, a completely new voltammetric picture was drawn where the standard reduction potential in aqueous solvent of 43 mV (SCE) was dramatically lowered and a new redox reaction with a higher reduction potential seemed to be present at -97mV (Ag/Ag+) when ferricyanide went through redox process from 0 V to +1.3 V to -0.5 V and back to 0V again. When examining the redox process an EC reaction was found to be coupled to the new peak. This process was studied within the time limit for the project. Some properties of the possible chemical has been presented and the conclusions are discussed in the report. Suggestions are made for how to move forward with the research. [i] (a) Gutmann V., Gritzner G., and Danksagmuller K., Inorganica Chimica Acta, 17 1976 81; (b) Noftle R.E. and Pletcher D., Journal of Electroanalytical Chemistry, 1990 273, 293.