| Title: | Decomposition of multifunctionalized alpha-alkoxyalkyl-hydroperoxides derived from the reactions of Criegee intermediates with diols in liquid phases |
| Author(s): | Endo Y; Sakamoto Y; Kajii Y; Enami S; |
| Address: | "Graduate School of Global Environmental Studies, Kyoto University, Kyoto, 606-8501, Japan. Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, 606-8316, 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: | "The oxidation of volatile organic compounds in the atmosphere produces organic hydroperoxides (ROOHs) that typically possess not only -OOH but also other functionalities such as -OH and -C(square with times signO). Because of their high hydrophilicity and low volatility, such multifunctionalized ROOHs are expected to be taken up in atmospheric condensed phases such as aerosols and fog/cloud droplets. However, the characteristics of ROOHs that control their fates and lifetimes in liquid phases are poorly understood. Here, we report a study of the liquid-phase decomposition kinetics of multifunctionalized alpha-alkoxyalkyl-hydroperoxides (alpha-AHs) that possessed an ether, a carbonyl, a hydroperoxide, and two hydroxy groups. These ROOHs were synthesized by ozonolysis of alpha-terpineol in water in the presence of 1,3-propanediol, 1,4-butanediol, or 1,5-pentanediol. Their decomposition products were detected as chloride anion adducts by electrospray mass spectrometry as a function of reaction time. Experiments using H(2)(18)O and D(2)O revealed that hemiacetal species were alpha-AH decomposition products that further transformed into other products. The result that the rate coefficients (k) of the decomposition of C(15) alpha-AHs increased exponentially from pH 5.0 to 3.9 was consistent with an H(+)-catalyzed decomposition mechanism. The temperature dependence of k and an Arrhenius plot yielded activation energies (E(a)) of 15.7 +/- 0.8, 15.0 +/- 2.4, and 15.9 +/- 0.3 kcal mol(-1) for the decomposition of alpha-AHs derived from the reaction of alpha-terpineol CIs with 1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol, respectively. The determined E(a) values were compared with those of related ROOHs. We found that alkyl chain length is not a critical factor for the decomposition mechanism, whereas the presence of additional -OH groups would modulate the reaction barriers to decomposition via the formation of hydrogen-bonding with surrounding water molecules. The derived E(a) values for the decomposition of the multifunctionalized, terpenoid-derived alpha-AHs will facilitate atmospheric modeling by serving as representative values for ROOHs in atmospheric condensed phases" |
| Keywords: | Aerosols Alcohols *Atmosphere *Hydrogen Peroxide Water; |
| Notes: | "MedlineEndo, Yasuyuki Sakamoto, Yosuke Kajii, Yoshizumi Enami, Shinichi eng England 2022/05/05 Phys Chem Chem Phys. 2022 May 18; 24(19):11562-11572. doi: 10.1039/d2cp00915c" |
