Amines React Rapidly with α-Hydroxyalkyl Hydroperoxides at the Air-Liquid Interface to Form Organic Nitrogen

Area of Science:

• Atmospheric Chemistry
• Environmental Science

Background:

• Organic nitrogen (ON) compounds impact aerosol chemistry and climate.
• Sources of atmospheric ON are not fully understood.

Purpose of the Study:

• Investigate the reaction of terpenoid-derived α-hydroxyalkyl hydroperoxides (α-HHs) with atmospheric amines.
• Determine the formation pathway of high-molecular-weight ON compounds.

Main Methods:

• Studied heterogeneous reactions between α-HHs and common atmospheric amines (ethylamine, dimethylamine, propylamine).
• Utilized isotope labeling experiments to confirm product structures and reaction mechanisms.
• Performed kinetic analysis to compare reaction rates with aqueous-phase hydrolysis.

Main Results:

• α-HHs react rapidly with atmospheric amines at the air-liquid interface, forming high-molecular-weight ON compounds.
• Isotope labeling confirmed product structures and elucidated the reaction mechanism.
• Heterogeneous reactions compete with aqueous hydrolysis; α-pinene-derived α-HHs half-life is ~19 min with 10 ppt ethylamine.

Conclusions:

• Amine interactions with α-HHs represent a significant source of ON in aerosols and cloud droplets.
• This pathway links biogenic volatile organic compounds to ON production.
• Provides mechanistic insight into nitrogen-containing aerosol formation and its implications for atmospheric chemistry.