香气萜烯香叶醇的空气氧化机理。

Mechanism of Air Oxidation of the Fragrance Terpene Geraniol.

机构信息

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.

出版信息

J Chem Theory Comput. 2008 Jan;4(1):101-6. doi: 10.1021/ct7001495.

DOI:10.1021/ct7001495

PMID:26619983

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.

摘要

香叶醇在暴露于空气中时会自动氧化，并形成氧化产物的混合物，其中一些是皮肤敏化剂。使用 DFT（B3LYP）研究了香叶醇与 O2 的反应，并将计算结果与实验观察到的产物比例进行了比较。氧化是通过氢提取引发的，形成烯丙基自由基，该自由基与 O2 分子结合生成中间过氧自由基。在随后的步骤中，香叶醇与之前研究过的情况不同，在之前的情况中，自由基链反应通过分子间氢提取来进行传播。羟基取代的烯丙基过氧自由基更倾向于进行分子内重排，产生可观察到的醛和氢过氧自由基，后者又可以继续引发自由基反应。还考虑了类似环氧化物和甲酸盐的次级氧化产物，并提出了形成它们的可能反应途径。