Abstract
During the course of the autoxidation of catechol in alkaline ethanol, ESR spectra were taken at certain intervals of the reaction time and as a result of that at the initial stage of the formation of hyperfine structure of o-benzosemiquinoae anion radicals, ESR spectrum of a triplet splitting was abserved in a relative intensity ratio of 1: 2: 1, with a coupling constant of 3.6 gauss. This spectrum was presumed to be attributed mainly due to two equivalent protons at positions 4 and 5, β-protons.
Each signal was then sglitted up 3 peaks of 1: 2: 1 with the coupling constant of 0.8 gauss, respectively, probabiy due to α-protons.
Hyperfine structure af o-benzosemiquinone anion radical which has signals with the relative intensity ratio of 1: 2: 1: 2: 4: 2: 1: 2: 1, was thus observed.
ESR spectrum changed soon to another triplet of 1: 2: 1 with the coupling constant of 0.65 gauss, which had been presumed to represent the hyperfine structure of the radical of dibenzo- [1, 4] -dioxin-2, 3-quinone, and was finally decayedwith time.
