Reaction Kinetics of Criegee Intermediates with Nitric Acid

This work investigated the reaction kinetics of HNO3 with four Criegee intermediates (CIs): CH2OO, (CH3)(2)COO, methyl vinyl ketone oxide (MVKO), and methacrolein oxide (MACRO). Our results show that these reactions are extremely fast with rate coefficients of (1.51 +/- 0.45) x 10(-10), (3.54 +/- 1.06) x 10(-10), (3.93 +/- 1.18) x 10(-10), and (3.0 +/- 1.0) x 10(-10) cm(3) s(-1) for reactions of HNO3 with CH2OO, (CH3)(2)COO, syn-MVKO, and anti-MACRO, respectively. This is consistent with previous results for the reactions between CIs and carboxylic acids, but the rate coefficient of CH2OO + HNO3 in the literature [Foreman et al. Angew. Chem. 2016, 128, 10575] was found to be overestimated by a factor of 3.6. In addition, we did not observe any significant pressure dependence in the HNO3 reactions with CH2OO and (CH3)(2)COO under 100-400 Torr. Our results indicate that in a dry area with severe NOx pollution, the reactions of CIs with HNO3 and their products may be worthy of attention, but these reactions may be insignificant under high-humidity conditions. However, CI reactions with HNO3 may not play an important role in the atmospheric removal processes of HNO3 because of the low concentrations of CIs.

Automated summary

This study investigated the reaction kinetics between HNO3 and four Criegee intermediates and found that these reactions are fast and occur under specific conditions. Under high-humidity conditions, these reactions may not be important.