Identification and Quantification of 4‑Nitrocatechol
Formed from OH and NO<sub>3</sub> Radical-Initiated Reactions of Catechol
in Air in the Presence of NO<sub><i>x</i></sub>: Implications
for Secondary Organic Aerosol Formation from Biomass Burning
Zachary Finewax
Joost A. de Gouw
Paul J. Ziemann
10.1021/acs.est.7b05864.s001
https://acs.figshare.com/articles/journal_contribution/Identification_and_Quantification_of_4_Nitrocatechol_Formed_from_OH_and_NO_sub_3_sub_Radical-Initiated_Reactions_of_Catechol_in_Air_in_the_Presence_of_NO_sub_i_x_i_sub_Implications_for_Secondary_Organic_Aerosol_Formation_from_Biomass_Burning/5853039
Catechol (1,2-benzenediol) is emitted from biomass burning and
produced from a reaction of phenol with OH radicals. It has been suggested
as an important secondary organic aerosol (SOA) precursor, but the
mechanisms of gas-phase oxidation and SOA formation have not been
investigated in detail. In this study, catechol was reacted with OH
and NO<sub>3</sub> radicals in the presence of NO<sub><i>x</i></sub> in an environmental chamber to simulate daytime and nighttime
chemistry. These reactions produced SOA with exceptionally high mass
yields of 1.34 ± 0.20 and 1.50 ± 0.20, respectively, reflecting
the low volatility and high density of reaction products. The dominant
SOA product, 4-nitrocatechol, for which an authentic standard is available,
was identified through thermal desorption particle beam mass spectrometry
and Fourier transform infrared spectroscopy and was quantified in
filter samples by liquid chromatography using UV detection. Molar
yields of 4-nitrocatechol were 0.30 ± 0.03 and 0.91 ± 0.06
for reactions with OH and NO<sub>3</sub> radicals, and thermal desorption
measurements of volatility indicate that it is semivolatile at typical
atmospheric aerosol loadings, consistent with field studies that have
observed it in aerosol particles. Formation of 4-nitrocatechol is
initiated by abstraction of a phenolic H atom by an OH or NO<sub>3</sub> radical to form a β-hydroxyphenoxy/<i>o</i>-semiquinone
radical, which then reacts with NO<sub>2</sub> to form the final product.
2018-01-22 00:00:00
3 radicals
desorption particle beam mass spectrometry
volatility
OH
yield
Catechol
formation
UV
phenolic H atom
Secondary Organic Aerosol Formation
4- nitrocatechol
SOA
3 Radical-Initiated Reactions
aerosol