Theoretical Insight into the Atmospheric Fate of Nerol: Mechanism and Rate Constant for Its Reaction with OH Radical

The atmospheric oxidation mechanism of nerol (NEL) initiated by an OH radical has been investigated using high-level quantum chemistry calculations. Computational results show that the addition pathways are more favorable than the H-abstraction ones, with CH2(OH)CH(OH)C·(CH3)CH2CH2CH═C(CH3)2 [IM1] and CH2(OH)CH═C(CH3)CH2CH2C·HC(OH)(CH3)2 [IM4 and IM4A] identified as the major addition intermediates. The overall rate constants, derived from the conventional transition state theory (CTST) over the temperature range of 220–400 K, can be expressed by the following fitted Arrhenius equation: k(T) = 2.2 × 10–24 × T4.1 × exp(2423/T) cm3 molecule–1 s–1. The predicted rate constant at 298 K agrees well with the experimental data. In the presence of O2/NO, the subsequent reactions of IM4 and IM4A lead to the major products of 6-hydroxy-4-methylhex-4-enal and acetone. In contrast, the further reaction of IM1 gives secondary products 6-methyl-5-hepten-2-one and glycolaldehyde. Our theoretical product distribution aligns with the experimental observations. Furthermore, the atmospheric lifetime of NEL initiated by the OH radical and the effect of its oxidation products on the atmosphere have also been discussed.