Mechanism of the photochemical transformation of naphthalene in water

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 123; no. 1; pp. 15 - 19
• Main Authors: Vialaton, Delphine, Richard, Claire, Baglio, Daniela, Paya-Perez, Ana-Beatriz
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.05.1999; Elsevier Science
• Subjects: Atomic and molecular physics; Chemistry; Exact sciences and technology; General and physical chemistry; Molecular properties and interactions with photons; Naphthalene; Photochemistry; Photoionization; Photon interactions with molecules; Phototransformation; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Physics; Water; Water; Phototransformation; Naphthalene; Photoionization; Quinone; Reaction mechanism; Photochemical reaction; Aqueous solution; Aldehyde; Experimental study; Laser photolysis
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/S1010-6030(99)00044-1

Upon irradiation in air-saturated aqueous solution, naphthalene is mainly converted into 7-hydroxy-1,4-naphthoquinone, 2-formylcinnamaldehyde and 2-carboxycinnamaldehyde. The quantum yield of photolysis is equal to 0.0025±0.0005. Naphthalene is likely to be phototransformed via monophotonic ionization that occurs with a quantum yield equal to 0.02. The radical cations formed after the electron ejection can deprotonate or react with water yielding radicals that are oxidized by molecular oxygen. Finally, 2-formylcinnamaldehyde and 2-carboxycinnamaldehyde are yielded. The production of 7-hydroxy-1,4-naphthoquinone is consistent with the intermediary formation of photolabile 1,4-naphtoquinone.