Mechanism of the Reaction of Methyl-p-benzoquinones with Sodium Sulfite in Acidic Buffer Solution

Abstract

Comparing the oxidation-reduction potentials of methyl-p-benzoquinones E0 with that of Na, S08 (Es.), the addition and the redox reactions of methyl-p-benzoquinones with Na₂SO^2- in acidic buffer solution were examined.
It was confirmed that under acidic conditions the redox reaction mainly proceeded when the difference (Eq Ess) was large and the addition reaction proceeded when the difference (Eq- E.) was small.
It was observed that these two reactions were influenced by the mechanism of the anodic oxidation of Na₂SO^2- and the addition reaction was sterically hindered by the methyl groups in cases of 2, 5-dimethyl-p-benzoquinone and trimethyl-p-benzoquinone.