31 Mar 2023
 | 31 Mar 2023

Technical Note: Improved synthetic routes to cis- and trans-(2-Methyloxirane-2,3-diyl)dimethanol (cis- and trans-β-isoprene epoxydiol)

Molly Frauenheim, Jason D. Surratt, Zhenfa Zhang, and Avram Gold

Abstract. We report improved synthetic routes to the isomeric isoprene-derived β-epoxydiols (β-IEPOX) in high yield (57–69 %) from inexpensive, readily available starting compounds. The syntheses do not require protection/deprotection steps or time-consuming purification of intermediates and can readily be scaled up to yield the target IEPOX isomers in gram quantities. Emissions of isoprene (2-methyl-1,3-butadiene, C5H8), primarily from deciduous vegetation, constitute the largest source of nonmethane atmospheric hydrocarbons. In the gas phase under low-nitric oxide (NO) conditions, addition of atmospheric hydroxyl radical (OH) followed by rapid addition of O2 yields isoprene-derived hydroxyperoxyl radicals. The major sink (> 90 %) for the peroxyl radicals is sequential reaction with hydroperoxyl radical (HO2), OH and O2, which is then followed by the elimination of OH to yield a ~2 : 1 mixture of (2-methyloxirane-cis/trans-2,3-dilyl)dimethanol (cis/trans-β-IEPOX). The IEPOX isomers account for about 80 % of the closed-shell hydroxyperoxyl products, and are rapidly taken up into acidic aerosols to form secondary organic aerosol (SOA). IEPOX-derived SOA makes a significant mass contribution to fine particulate matter (PM2.5), which is known to be a major factor in climate forcing as well as adversely affects respiratory and cardiovascular systems of exposed populations. Prediction of ambient PM2.5 composition and distribution, both in regional- and global-scale atmospheric chemistry models, crucially depends on the accuracy of identification and quantitation of uptake product formation. Accessibility of authentic cis- and trans-β-IEPOX in high purity and in large quantity for laboratory studies underpins progress in developing models as well as identification and quantitation of PM2.5 components.

Molly Frauenheim et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-476', Anonymous Referee #1, 11 Apr 2023
  • RC2: 'Comment on egusphere-2023-476', Anonymous Referee #2, 19 Apr 2023
  • CC1: 'Comment on egusphere-2023-476', Magda Claeys, 01 May 2023
  • AC1: 'Comment on egusphere-2023-476', Avram Gold, 24 May 2023

Molly Frauenheim et al.

Molly Frauenheim et al.


Total article views: 287 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
223 51 13 287 21 3 3
  • HTML: 223
  • PDF: 51
  • XML: 13
  • Total: 287
  • Supplement: 21
  • BibTeX: 3
  • EndNote: 3
Views and downloads (calculated since 31 Mar 2023)
Cumulative views and downloads (calculated since 31 Mar 2023)

Viewed (geographical distribution)

Total article views: 298 (including HTML, PDF, and XML) Thereof 298 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 29 May 2023
Short summary
Atmospheric oxidation products of isoprene, the major non-methane volatile organic hydrocarbon emitted into earth’s atmosphere, are major precursors of fine particulate matter. Understanding the formation fine particulate matter requires authentic precursors. We have developed synthetic routes to precursors that are accessible to atmospheric research laboratories do not have sophisticated capabilities in chemical synthesis.