A Possible Mechanism for Furan Formation in the Tropospheric Oxidation of Dienes

• Published in: Environmental science & technology Vol. 39; no. 22; pp. 8797 - 8802
• Main Authors: Francisco-Márquez, Misaela, Alvarez-Idaboy, J. Raúl, Galano, Annia, Vivier-Bunge, Annik
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.11.2005
• Subjects: Applied sciences; Atmospheric chemistry; Atmospheric pollution; Butadienes - chemistry; Chemistry Techniques, Analytical; Exact sciences and technology; Furans - chemistry; Hemiterpenes - chemistry; Hydroxyl Radical; Oxidation; Oxidation-Reduction; Pentanes - chemistry; Pollutants; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution; Software; Five membered ring; Pollutant formation; Furan derivatives; Troposphere; Dienic compound; Oxygen heterocycle; Precursor; Free radical reaction; Butadiene; Ethylenic aliphatic compound; Atmospheric chemistry; Reaction mechanism; Hydroxyl radicals; Air pollution; Isoprene; Organic compounds
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es0500714

The isoprene + OH gas-phase reaction has been widely studied because of its relevance in tropospheric chemistry. However, an unsolved question remains concerning the mechanism for the formation of the observed 3-methylfuran. OH addition to dienes, such as isoprene and butadiene, is assumed to occur only at the external carbon atoms, thus restricting furan formation to a step after addition at C1 and C4. Moreover, cyclization of the carbon chain necessarily involves a cis conformation. In this work, several quantum chemistry methods have been used to model five different reaction paths for furan formation. A mechanism that is highly favored for intermediates that do not undergo collisional stabilization has been identified.