Atmospheric chemistry of diazomethane – an experimental and theoretical study

Abstract

The kinetics of the O₃, OH and NO₃ radical reactions with diazomethane were studied in smog chamber experiments employing long-path FTIR and PTR-ToF-MS detection. The rate coefficients were determined to be k_CH2NN+O3 = (3.2 ± 0.4) × 10⁻¹⁷ and k_CH2NN+OH = (1.68 ± 0.12) × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹ at 295 ± 3 K and 1013 ± 30 hPa, whereas the CH₂NN + NO₃ reaction was too fast to be determined in the static smog chamber experiments. Formaldehyde was the sole product observed in all the reactions. The experimental results are supported by CCSD(T*)-F12a/aug-cc-pVTZ//M062X/aug-cc-pVTZ calculations showing the reactions to proceed exclusively via addition to the carbon atom. The atmospheric fate of diazomethane is discussed.

GRAPHICAL ABSTRACT

KEYWORDS:

• Atmospheric chemistry
• reaction mechanism
• amine photo-oxidation
• quantum chemistry

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Claus J. Nielsen http://orcid.org/0000-0002-2962-2634

Armin Wisthaler http://orcid.org/0000-0001-5050-3018

Additional information

Funding

This work is part of the Atmospheric Chemistry of Amines project (ACA) supported by the CLIMIT program under contract 244055 and has received additional support from the Research Council (Norges Forskningsråd) of Norway through its Centres of Excellence scheme, project number 262695.