Photochemical Reaction of Azoxybenzenes in the Presence of Acetic Acid
Jiro YAMAMOTO*, Ryuji HAMADA and Takasi TSUBOI
Department of Materials Science, Faculty of Engineering, Tottori University, Koyama-cho, Tottori-shi 680-8552 Japan
When each benzene solution of azoxybenzene, 2,2'-dimethylazoxybenzene, 4,4'-dimethylazoxybenzene, 2,2'-dichloroazoxybenzene and 4,4'-dichloroazoxybenzene was irradiated with UV light in the presence of acetic acid. The corresponding 2-hydroxyazobenzene was obtained in higher yield than in the absence of the acid. Rearrangement products 2-hydroxy-4-methylazobenzene(8) and 2-hydroxy-4'-methylazobenzene(9) were also obtained in higher yield under the UV irradiation of 4-methyl-ONN-azoxybenzene(7α)(α : β=3.5F1.0) in the presence of acetic acid. Under the same reaction conditions, two rearrangement products 8 and 9 were also obtained from 4-methyl-NNO- azoxybenzene(7β)(α : β=0.0 : 1.0). The β,α-isomerization from 7β; to 7α did not take place at all in this reaction. This was different from the photochemical reaction of 7β(α : β=0.0 : 1.0) in the presence of trichloroacetic acid. The product yields of 8 and 9 seem to be dependent on the concentration of acetic acid.