Reactions of stabilized criegee intermediates from the gas-phase reactions of O3 with selected alkenes

✍ Scribed by Jillian Baker; Sara M. Aschmann; Janet Arey; Roger Atkinson

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 228 KB
• Volume: 34
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10022

✦ Synopsis

Abstract

The gas‐phase reactions of O~3~ with 1‐octene, trans‐7‐tetradecene, 1,2‐dimethyl‐1‐cyclohexene, and α‐pinene have been studied in the presence of an OH radical scavenger, primarily using in situ atmospheric pressure ionization tandem mass spectrometry (API‐MS), to investigate the products formed from the reactions of the thermalized Criegee intermediates in the presence of water vapor and 2‐butanol (1‐octene and trans‐7‐tetradecene forming the same Criegee intermediate). With H~3~O^+^(H~2~O)~n~ as the reagent ions, ion peaks at 149 u ([M + H]^+^) were observed in the API‐MS analyses of the 1‐octene and trans‐7‐tetradecene reactions, which show a neutral loss of 34 u (H~2~O~2~) and are attributed to the α‐hydroxyhydroperoxide CH~3~(CH~2~)~5~CH(OH)OOH, which must therefore have a lifetime with respect to decomposition of tens of minutes or more. No evidence for the presence of α‐hydroxyhydroperoxides was obtained in the 1,2‐dimethyl‐1‐cyclohexene or α‐pinene reactions, although the smaller yields of thermalized Criegee intermediates in these reactions makes observation of α‐hydroxyhydroperoxides from these reactions less likely than from the 1‐octene and trans‐7‐tetradecene reactions. Quantifications of 2,7‐octanedione from the 1,2‐dimethyl‐1‐cyclohexene reactions and of pinonaldehyde from the α‐pinene reactions were made by gas chromatographic analyses during reactions with cyclohexane and with 2‐butanol as the OH radical scavenger. The measured yields of 2,7‐octanedione from 1,2‐dimethyl‐1‐cyclohexene and of pinonaldehyde from α‐pinene were 0.110 ± 0.020 and 0.164 ± 0.029, respectively, and were independent of the OH radical scavenger used. Reaction mechanisms are presented and discussed. © 2001 Wiley Periodicals, Inc. Int J Chem Kinet 34: 73–85, 2002