Formation of hydrogen peroxide from coal tar as hydrogen sources using 9-mesityl-10-methylacridinium ion as an effective photocatalyst

Visible light irradiation of an O₂-saturated acetonitrile (MeCN) solution containing 9-mesityl-10-methylacridinium ion (Acr⁺-Mes) and MeCN-extracted coal tar results in formation of hydrogen peroxide (H₂O₂). Anthracene and other aromatic hydrocarbons contained in coal tar act as hydrogen sources in the photocatalytic reduction of O₂ to produce H₂O₂. The photocatalytic formation of H₂O₂ is initiated by photoexcitation of Acr⁺-Mes, which results in formation of the electron-transfer state: Acr{radical dot}-Mes{radical dot}⁺, followed by electron-transfer from coal tar to the Mes{radical dot}⁺ moiety and electron-transfer from the Acr{radical dot} moiety to O₂.