Photoinduced organic transformation. Selective synthesis of ethylene glycol or formic acid and methyl formate from methanol in the presence of hydrogen peroxide

Article abstract of DOI:10.1246/bcsj.63.97

The photoinduced transformation of methanol (MeOH) has been investigated in the presence of H₂O₂. Ethylene glycol (EG) was selectively produced by UV light irradiation of the N₂-saturated MeOH and the selectivity was 85-94% below 3 ml h^-1 of H₂O₂ feeding rate (f). The quantity of EG reached the maximum at f=5 ml h^-1 and the quantum yield was 0.73. EG was produced through the dimerization of hydroxymethyl radicals formed by the abstraction of hydrogen atom from MeOH by hydroxyl radical which was formed by the photolysis of H₂O₂. On the other hand, formic acid (FA) and methyl formate (MF) were selectively produced by UV light irradiation of the O₂-bubbled MeOH and the combined selectivity was about 99% in the f range of 1-8 ml h^-1. The quantities of FA and MF reached the maximum at f=5 ml h^-1 and their quantum yields were 1.36 and 0.69, respectively. FA was mainly produced through the decomposition of hydroperoxyhydroxymethane formed by the abstraction of hydrogen atom from MeOH by hydroxymethyldioxy radical which was formed by the reaction of hydroxymethyl radical with oxygen, and MF through the reaction of MeOH with FA formed.