2 超音波照射を活用したヒドロキシ基導入反応

概要

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Various phenolic compounds and polyphenols were produced using ultrasonication in the hydroxylation reaction. In the aqueous solution, ultrasonication was useful for producing hydroxyl radical from water. Hydroxylation was also known in the production via epoxy compound. In the method via epoxy compounds high pressure or strong acidic conditions are necessary. Various monophenols substituted with alkyl and methoxy groups were reacted with hydroxyl radicals producing under ultrasonic irradiation(Sus-4005C, 50W, 40kHz and Kaijo, 200kHz) for 12-24h to give the corresponding polyphenolic compounds. When no irradiation of ultrasound was done in this reaction, no reaction was found. The effect of irradiation of ultrasound accelerated the hydroxylation of phenolic compounds. In the case of using cupric acetate in acetic acid, acetoxylation was also accelerated under ultrasonication. When catechols were reacted under oxygen and ultrasound irradiation in aqueous solution, pyrogallols were produced exceptionally. When resorcinols were reacted under the same condition, pyrogallols were also obtained. In the case of 2-t-butyl-4-methoxyphenol with cupric acetate under irradiation of ultrasound in acetic acid, 6-acetoxy-2-t-butyl-4-methoxyphenol was produced in good yield to give 3-t-butyl-5-methoxycatechol quantitatively.
日本ソノケミストリー学会の論文