Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The effect of bifunctional alcohols ethylene glycol (EG) and 1,2-propylene glycol (1,2 PG) on the kinetic parameters for the irreversible chromate ion reduction were investigated by polarographic and coulometric methods of analysis. The electroreduction of chromate ion in neutral bifunctional alcohol solutions proceeds according to the scheme: Cr(VI)–Cr(III)–Cr(II) and the values of the standard rate constant k^*₀ decrease in the order H₂O > EG > 1,2 PG. The values of real activation energy, Q, activation energy of diffusion, Q_D, and frequency factor log A° have been calculated. The obtained values of Q_D as well as Q proved the diffusion nature of limiting current. The values of the frequency factor log A° decrease in the order H₂O > EG > 1,2 PG, which points to a less favourable orientation of the electroactive ions at the electrode surface in glycols.