Theoretical investigation of linalool oxidation

Area of Science:

• * Computational chemistry
• * Chemical kinetics
• * Allergenicity studies

Background:

• * Linalool is a widely used fragrance ingredient.
• * Autoxidation of linalool produces hydroperoxides, known contact allergens.
• * Understanding oxidation pathways is crucial for assessing allergenicity.

Purpose of the Study:

• * Investigate the reaction pathways of linalool autoxidation.
• * Characterize the intermediate states in the oxidation process.
• * Support experimental findings on linalool oxidation products.

Main Methods:

• * Quantum mechanical electronic structure calculations.
• * Density Functional Theory (DFT) for geometry optimization and vibrational frequencies.
• * Systematic investigation of smaller model systems (propene, 2-methyl-2-butene, 2-methyl-2-pentene).

Main Results:

• * Characterization of the linalool-O2 biradical intermediate state.
• * Identification of branching points for further oxidation reactions.
• * Theoretical framework supports the major experimental hydroperoxide product: 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol.

Conclusions:

• * The study elucidates key reaction mechanisms (direct, ene-type, radical) in linalool autoxidation.
• * Computational results align with experimental observations of oxidation products.
• * Provides a theoretical basis for understanding the formation of linalool-derived allergens.