Pyrimidine in aqueous media

Abstract

The electrochemical reduction of pyrimidine in aqueous media was studied using alternating current (a.c.) polarography. Over the pH-range, 0.5-13, five moderately to highly irreversible a.c. waves were observed, which corresponded to the five waves observed on d.c. polarography. Although the electrochemical reduction path of pyrimidine is complex and only partially understood, good qualitative agreement between the features of the mechanism and various polarographic parameters was achieved, providing further support for the proposed mechanism, and indicaing the validity of the current theoretical and experimental results in the area of the a.c. polarography of quasi-reversible electrode reactions. Summit potentials for the five waves, which vary linearly with pH, are independent of applied alternating voltage, mercury column height (drop-time) and concentration, but shift to more negative potential with increasing frequency. Total alternating current for all waves increases linearly with amplitude of applied alternating voltage and the negative square root of droptime; plots of total alternating current vs. square root of applied frequency exhibit curvilinear trends with a maximum in the range, 15-50 Hz.