Highly Oxidized RO2 Radicals and Consecutive Products from the Ozonolysis of Three Sesquiterpenes
| Autor: | Hartmut Herrmann, Torsten Berndt, Stefanie Richters |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Ozone
Free Radicals 010504 meteorology & atmospheric sciences Radical chemistry.chemical_element Acetates 010402 general chemistry Mass spectrometry 01 natural sciences Oxygen Mass Spectrometry chemistry.chemical_compound Nitrate Environmental Chemistry Organic chemistry Moiety 0105 earth and related environmental sciences Ions Polycyclic Sesquiterpenes Volatile Organic Compounds Nitrates Ozonolysis Atmosphere General Chemistry 0104 chemical sciences Monocyclic Sesquiterpenes chemistry Oxidation-Reduction Sesquiterpenes Carbon |
| Zdroj: | Environmental Science & Technology. 50:2354-2362 |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/acs.est.5b05321 |
| Popis: | The formation of highly oxidized multifunctional organic compounds (HOMs) from the ozonolysis of three sesquiterpenes, α-cedrene, β-caryophyllene, and α-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 α-cedrene (acetate), 1.8% for β-caryophyllene (acetate), and 1.4% for α-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 α-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. |
| Databáze: | OpenAIRE |
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