title: Theoretical investigation of linalool oxidation.
abstract: This study concerns the autoxidation of one of the most used fragrances in daily life, linalool (3,7-dimethyl-1,6-octadien-3-ol). It reacts with O2 to form hydroperoxides, which are known to be important contact allergens. Pathways for hydroperoxide formation are investigated by means of quantum mechanical electronic structure calculations. Optimized molecular geometries and harmonic vibrational frequencies are determined using density functional theory (DFT). Insight into how the addition of O2 to linalool occurs is obtained by establishing a theoretical framework and systematically investigating three smaller systems: propene, 2-methyl-2-butene, and 2-methyl-2-pentene. 2-Methyl-2-pentene was chosen as a model system and used to compare with linalool. This theoretical study characterizes the linalool-O2 biradical intermediate state, which constitutes a branching point for the further oxidation reactions pathways. Thus, the observed linalool oxidation product spectrum is discussed in terms of a direct reaction path, the ene-type mechanism, and the radical mechanism. The major hydroperoxide found in experiments is 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol, and the calculated results support this finding.
authors.affiliation: Department of Chemistry, Physical Chemistry, Electrochemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden. carina@chem.gu.se
authors.forename: Carina
authors.initials: C
authors.lastname: Bäcktorp
authors.forename: J R Tobias Johnson
authors.initials: JR
authors.lastname: Wass
authors.forename: Itai
authors.initials: I
authors.lastname: Panas
authors.forename: Maria
authors.initials: M
authors.lastname: Sköld
authors.forename: Anna
authors.initials: A
authors.lastname: Börje
authors.forename: Gunnar
authors.initials: G
authors.lastname: Nyman
mesh_terms: D000080462:Acyclic Monoterpenes; D000475:Alkenes / Q000737:chemistry*; D003198:Computer Simulation; D005233:Fatty Alcohols / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D039821:Monoterpenes / Q000737:chemistry*; D010084:Oxidation-Reduction; D011789:Quantum Theory
chemical_list: C522291:2-methyl-2-pentene; C522293:7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol; D000080462:Acyclic Monoterpenes; D000475:Alkenes; D005233:Fatty Alcohols; D005609:Free Radicals; D007306:Insecticides; D039821:Monoterpenes; C018584:linalool