Temperature-dependent aqueous OH kinetics of C.sub.2-C.sub.10 linear and terpenoid alcohols and diols: new rate coefficients, structure-activity relationship, and atmospheric lifetimes

Aliphatic alcohols (AAs), including terpenoic alcohols (TAs), are ubiquitous in the atmosphere due to their widespread emissions from natural and anthropogenic sources. Hydroxyl radical (OH) is the most important atmospheric oxidant in both aqueous and gas phases. Consequently, the aqueous oxidation of the TAs by the OH inside clouds and fogs is a potential source of aqueous secondary organic aerosols (.sub.aq SOAs). However, the kinetic data, necessary for estimating the timescales of such reactions, remain limited. Here, bimolecular rate coefficients (kOHaq) for the aqueous oxidation of 29 C.sub.2 -C.sub.10 AAs by hydroxyl radicals (OH) were measured with the relative rate technique in the temperature range 278-328 K. The values of kOHaq for the 15 AAs studied in this work were measured for the first time after validating the experimental approach. The kOHaq values measured for the C.sub.2 -C.sub.10 AAs at 298 K ranged from 1.80 x 10.sup.9 to 6.5 x 10.sup.9 M.sup.-1 s.sup.-1 . The values of activation parameters, activation energy (7-17 kJ mol.sup.-1 ), and average Gibbs free energy of activation (18 ± 2 kJ mol.sup.-1) strongly indicated the predominance of the H-atom abstraction mechanism. The estimated rates of the complete diffusion-limited reactions revealed up to 44 % diffusion contribution for the C.sub.8 -C.sub.10 AAs.