title: Mechanism of Air Oxidation of the Fragrance Terpene Geraniol.
abstract: The fragrance terpene geraniol autoxidizes upon air exposure and forms a mixture of oxidation products, some of which are skin sensitizers. Reactions of geraniol with O2 have been studied with DFT (B3LYP) and the computational results compared to experimentally observed product ratios. The oxidation is initiated by hydrogen abstraction, forming an allylic radical which combines with an O2 molecule to yield an intermediate peroxyl radical. In the subsequent step, geraniol differs from previously studied cases, in which the radical chain reaction is propagated through intermolecular hydrogen abstraction. The hydroxy-substituted allylic peroxyl radical prefers an intramolecular rearrangement, producing observable aldehydes and the hydroperoxyl radical, which in turn can propagate the radical reaction. Secondary oxidation products like epoxides and formates were also considered, and plausible reaction pathways for formation are proposed.
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Carina
authors.initials: C
authors.lastname: Bäcktorp
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Hagvall
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Börje
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Ann-Therese
authors.initials: AT
authors.lastname: Karlberg
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Per-Ola
authors.initials: PO
authors.lastname: Norrby
authors.affiliation: Department of Chemistry, Physical Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden, Department of Chemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden, and Department of Chemistry, Organic Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Nyman