Obtaining of pyrazine-2,3-dicarboxylic acid through electrochemical quinoxaline oxidation using copper alloys as anodes [articol]

Abstract

Previous studies have shown that quinoxaline (Q) oxidation with electrochemically regenerated KMnO4, with the formation of pyrazine-2,3-dicarboxylic acid (PDCA), is possible using Pt, Ni, stainless steel and Cu electrodes. In order to improve current knowledge and to expand the variety of electrodes used for the pyrazine-2,3-dicarboxilic acid (PDCA) production process, we investigated the behavior of the copper alloy anodes – brass and bronze. A laboratory electrolyser for PDCA synthesis with copper alloy anode was manufactured. Depending on the anode – copper, brass and bronze - the effect of various parameters on the current and substance efficiencies was investigated. These parameters are: anodic current density, amount of electricity, temperature and initial concentration of quinoxaline. The best performances of this electrolyser are ~88% current efficiencies on the brass electrode and up to 80% substance efficiencies on the bronze electrode, at a current density of 3,5 A/dm2. These performances are greater than those obtained on the copper anode.