Photochemistry of acenaphthene at a silica gel/air interface

The photolysis of acenapthene (ACE) has been studied at a silica gel/air interface. Direct photolysis leads to 1-acenaphthenol as the principal photoproduct. Secondary photochemical conversion of the alcohol into 1-acenaphthenone is also observed. Reactions leading to formation of both 1-acenaphthenol and 1-acenaphthenone are attributed to electron-transfer oxidation mechanisms and the cation radical of ACE is directly observed by transient diffuse reflectance spectroscopy. Preconditioning the silica gel by heating at 200 degrees C in air partially removes physisorbed water from the silica surface and photochemical conversion of ACE is observed to occur faster. (C) 1998 Elsevier Science S.A.