Abstract. The multivariate relative rate method was applied to a range of volatile organic compounds (VOC) reactions with OH. This previously published method (Shaw et al., 2018b) was improved to increase the sensitivity towards slower reacting VOC, broadening the range of compounds which can be examined. A total of thirty-five room temperature relative rate coefficients were determined; eight of which have not previously been reported. Five of the new reaction rate coefficients were for large alkyl substituted monoaromatic species recently identified in urban air masses, likely with large ozone production potentials. The new results (with kOH (296 K) values in units of 10–12 cm3 molecule−1 s−1) were: n-butylbenzene, 11 (± 4); n-pentylbenzene, 7 (± 2); 1,2-diethylbenzene, 14 (± 4); 1,3-diethylbenzene, 22 (± 4) and 1,4-diethylbenzene, 16 (± 4). Interestingly, whilst results for smaller VOC agreed well with available structure activity relationship (SAR) calculations, the larger alkyl benzenes were found to be less reactive than the SAR prediction, indicating that our understanding of the oxidation chemistry of these compounds is still limited. kOH (296 K) rate coefficients (in units of 10–12 cm3 molecule−1 s−1) for reactions of three large alkanes with OH were also determined for the first time: 2-methylheptane, 9.1 (± 0.3); 2-methylnonane, 11.0 (± 0.3) and ethylcyclohexane, 14.4 (± 0.3), all in reasonable agreement with SAR predictions. Rate coefficients for the twenty-seven previously studied OH + VOC reactions agreed well with available literature values, lending confidence to the application of this method for the rapid and efficient simultaneous study of gas-phase reaction kinetics.
Supplementary material to "Rate coefficients for reactions of OH with aromatic and aliphatic volatile organic compounds determined by the Multivariate Relative Rate Technique"