Title: | Highly Oxidized RO2 Radicals and Consecutive Products from the Ozonolysis of Three Sesquiterpenes |
Author(s): | Richters S; Herrmann H; Berndt T; |
Address: | "Leibniz Institute for Tropospheric Research, TROPOS , Permoserstrasse 15, 04318 Leipzig, Germany" |
ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
Abstract: | "The formation of highly oxidized multifunctional organic compounds (HOMs) from the ozonolysis of three sesquiterpenes, alpha-cedrene, beta-caryophyllene, and alpha-humulene, was investigated for the first time. Sesquiterpenes contribute 2.4% to the global carbon emission of biogenic volatile organic compounds (BVOCs) and can be responsible for up to 70% of the regional BVOC emissions. HOMs were detected with chemical ionization-atmospheric pressure interface-time-of-flight mass spectrometry and nitrate and acetate ionization. Acetate ions were more sensitive toward highly oxidized RO2 radicals containing a single hydroperoxide moiety. Under the chosen reaction conditions, product formation was dominated by highly oxidized RO2 radicals which react with NO, NO2, HO2, and other RO2 radicals under atmospheric conditions. The ozonolysis of sesquiterpenes resulted in molar HOM yields of 0.6% for alpha-cedrene (acetate), 1.8% for beta-caryophyllene (acetate), and 1.4% for alpha-humulene (nitrate) afflicted with an uncertainty factor of 2. Molar yields of highly oxidized RO2 radicals were identical with HOM yields measuring the corresponding closed-shell products. HOM formation from ozonolysis of alpha-cedrene was explained by an autoxidation mechanism initiated by ozone attack at the double bond similar to that found in the ozonolysis of cyclohexene and limonene" |
Keywords: | Acetates/chemistry Atmosphere/chemistry Free Radicals/*chemistry Ions Mass Spectrometry Monocyclic Sesquiterpenes Nitrates/chemistry Oxidation-Reduction Oxygen/*chemistry Ozone/*chemistry Polycyclic Sesquiterpenes Sesquiterpenes/*chemistry Volatile Organi; |
Notes: | "MedlineRichters, Stefanie Herrmann, Hartmut Berndt, Torsten eng Research Support, Non-U.S. Gov't 2016/02/03 Environ Sci Technol. 2016 Mar 1; 50(5):2354-62. doi: 10.1021/acs.est.5b05321. Epub 2016 Feb 10" |