On the early reaction stages of ozone with N,N′-substituted p-phenylenediamines (6PPD, 77PD) and N,N′,N″-substituted-1,3,5-triazine “Durazone®”: An electron spin resonance (ESR) and electronic absorption spectroscopy study

The early stages of the reaction mechanism of ozone with N,N′-substituted p-phenylenediamines 6PPD and 77PD as well as the alkyl-p-phenylenediamine substituted sym-triazine (PPDTZ) commercially known as “DURAZONE” were investigated at room temperature in ethanol and acidic ethanol solutions with electron spin resonance (ESR) and electronic absorption spectroscopy (UV-VIS). It was found that both 6PPD and 77PD react with ozone through the electron transfer mechanism giving the respective radical cations 6PPD+ and 77PD+ which were detected with ESR and with UV-VIS. It was also found that 6PPD+ and 77PD+ are stabilized and clearly detected in acidic ethanol. In the case of 6PPD ozonation also gave the relative nitroxyl radical which was detected with ESR. PPDTZ was reacted with ozone in ethanol to give a nitroxyl radical detected with ESR and with UV-VIS spectroscopy. No radical cation was detected on ozonated PPDTZ solutions.