Pulse radiolysis study of 2,6-pyridine dicarboxylic acid in aqueous solutions

The reactions of primary species of water radiolysis viz. e(aq)(-), H-atom and OH radicals and some one electron reductants with 2,6-pyridine dicarboxylic acid were studied at various pHs. The rate constants for these reactions were determined and the values were found to be in the range of 0.3-1 x 10(10) dm(3) mol(-1) s(-1). Spectral, kinetic, redox and acid-base properties of the transient species were also studied. The transient species formed by e(aq)(-) reaction have absorption maxima around 300 and 390 nm. The pk(a) values of the semireduced species were determined to be 2.1 and 5.4. These species were found to be strong reductants. The species produced by H-atom reaction was also able to reduce methyl viologen but to a lesser extent indicating that only a part of the species produced by H-atom reaction are reducing in nature. OH radicals react by addition to the pyridine ring. The transient spectra have absorption maxima around 350 and 500 nm. pK(a) values of the OH adducts were determined to be 2.1 and 4.5. Copyright (C) 1997 Elsevier Science Ltd