Title: | Aqueous-phase fates of alpha-alkoxyalkyl-hydroperoxides derived from the reactions of Criegee intermediates with alcohols |
Author(s): | Hu M; Qiu J; Tonokura K; Enami S; |
Address: | "Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8563, Japan. National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan. enami.shinichi@nies.go.jp" |
ISSN/ISBN: | 1463-9084 (Electronic) 1463-9076 (Linking) |
Abstract: | "In the atmosphere, carbonyl oxides known as Criegee intermediates are produced mainly by ozonolysis of volatile organic compounds containing C[double bond, length as m-dash]C double bonds, such as biogenic terpenoids. Criegee intermediates can react with OH-containing species to produce labile organic hydroperoxides (ROOHs) that are taken up into atmospheric condensed phases. Besides water, alcohols are an important reaction partner of Criegee intermediates and can convert them into alpha-alkoxyalkyl-hydroperoxides (alpha-AHs), R1R2C(-OOH)(-OR'). Here, we report a study on the aqueous-phase fates of alpha-AHs derived from ozonolysis of alpha-terpineol in the presence of methanol, ethanol, 1-propanol, and 2-propanol. The alpha-terpineol alpha-AHs and the decomposition products were detected as their chloride adducts by electrospray mass spectrometry as a function of reaction time. Our discovery that the rate of decomposition of alpha-AHs increased as the pH decreased from 5.9 to 3.8 implied that the decomposition mechanism was catalyzed by H+. The use of isotope solvent experiments revealed that a primary decomposition product of alpha-AHs in an acidic aqueous solution was a hemiacetal R1R2C(-OH)(-OR') species that was further transformed into other products such as lactols. The proposed H+-catalyzed decomposition of alpha-AHs, which provides H2O2 and multifunctional species in ambient aerosol particles, may be faster than other degradation processes (e.g., photolysis by solar radiation)" |
Notes: | "PubMed-not-MEDLINEHu, Mingxi Qiu, Junting Tonokura, Kenichi Enami, Shinichi eng England 2021/02/24 Phys Chem Chem Phys. 2021 Mar 4; 23(8):4605-4614. doi: 10.1039/d0cp06308h" |