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Effects of Metal Ions on Aqueous-Phase Decomposition of α-Hydroxyalkyl-Hydroperoxides Derived from Terpene Alcohols.
- Source :
-
Environmental science & technology [Environ Sci Technol] 2021 Oct 05; Vol. 55 (19), pp. 12893-12901. Date of Electronic Publication: 2021 Sep 16. - Publication Year :
- 2021
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Abstract
- We report the results of a mass spectrometric study of the effects of atmospherically relevant metal ions on the decomposition of α-hydroxyalkyl-hydroperoxides (α-HHs) derived from ozonolysis of α-terpineol in aqueous solutions. By direct mass spectrometric detection of chloride adducts of α-HHs, we assessed the temporal profiles of α-HHs and other products in the presence of metal ions. In addition, reactions between α-HHs and FeCl <subscript>2</subscript> in the presence of excess DMSO showed that the amount of hydroxyl radicals formed in a mixture of α-terpineol, O <subscript>3</subscript> , and FeCl <subscript>2</subscript> was 5.7 ± 0.8% of the amount formed in a mixture of H <subscript>2</subscript> O <subscript>2</subscript> and FeCl <subscript>2</subscript> . The first-order rate constants for the decay of α-HHs produced by ozonolysis of α-terpineol in the presence of 5 mM acetate buffer at a pH of 5.1 ± 0.1 were determined to be (4.5 ± 0.1) × 10 <superscript>-4</superscript> s <superscript>-1</superscript> (no metal ions), (4.7 ± 0.2) × 10 <superscript>-4</superscript> s <superscript>-1</superscript> (with 0.05 mM Fe <superscript>2+</superscript> ), (4.7 ± 0.1) × 10 <superscript>-4</superscript> s <superscript>-1</superscript> (with 0.05 mM Zn <superscript>2+</superscript> ), and (4.8 ± 0.2) × 10 <superscript>-4</superscript> s <superscript>-1</superscript> (with 0.05 mM Cu <superscript>2+</superscript> ). We propose that in acidic aqueous media, the reaction of α-HHs with Fe <superscript>2+</superscript> is outcompeted by H <superscript>+</superscript> -catalyzed decomposition of α-HHs, which produces the corresponding aldehydes and H <subscript>2</subscript> O <subscript>2</subscript> , which can in turn react with Fe <superscript>2+</superscript> to form hydroxyl radicals.
- Subjects :
- Hydroxyl Radical
Terpenes
Water
Alcohols
Hydrogen Peroxide
Subjects
Details
- Language :
- English
- ISSN :
- 1520-5851
- Volume :
- 55
- Issue :
- 19
- Database :
- MEDLINE
- Journal :
- Environmental science & technology
- Publication Type :
- Academic Journal
- Accession number :
- 34525797
- Full Text :
- https://doi.org/10.1021/acs.est.1c04635