Unexpected 2,4,6-trimethylphenol oxidation in the presence of Fe(iii) aquacomplexes

Abstract

2,4,6-Trimethylphenol (TMP) was efficiently oxidised by Fe(III) aquacomplexes. HPLC analysis was used to follow the kinetics of the redox process. Two degradation products were detected and identified: 2,6-dimethyl-4-(hydroxymethyl)phenol (P1) and 3,5-dimethyl-4-hydroxybenzaldehyde (P2) accounting for 100% of TMP degradation in the early stages of the reaction. The formation of the products was concomitant with the reduction of Fe(III) into Fe(II). The direct relation between TMP oxidation and the concentration of the monomeric species {Fe(H₂O)₅(OH)}²⁺ gives evidence for the initial reaction to take place between TMP and this particular species. Moreover, the correlation between P2 formation and P1 disappearance during the reaction implies the sequence of reactions: TMP → P1 → P2. A mechanism leading to the two degradation products is proposed.