CONTINUOUS PHOTOREDUCTION OF METHYL VIOLOGEN USING DISUBSTITUTED TERTHIOPHENES AND EDTA IN AQUEOUS-SOLUTION

The continuous photoreduction of methyl viologen by 5,5 ''-bis(aminome thyl)-2,2':5',2 ''-terthiophene (AT) and 2,2':5',2 ''-terthiophene-5,5 ''-dicarbuxyl acid (CT), using EDTA as a sacrificial electron donor, has been investigated in aqueous solution at various pH. Apparent rate s and efficiencies of production of the methyl viologen radical cation (MV.+) were found to be dependent on the pH, the concentrations of al l three components and the intensity of the incident light, The highes t conversion efficiency (77%) was shown by the bis(aminomethyl)-substi tuted terthiophene AT at pH 7.7. The quantum yield for the formation o f MV.+ under these conditions was 0.24, which is comparable with other common systems.