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An experimental study on the temperature dependence for the gas-phase reactions of NO3 radical with a series of aliphatic aldehydes

An experimental study on the temperature dependence for the gas-phase reactions of NO3 radical with a series of aliphatic aldehydes

Authors :
Martin, P.
Salgado, S.
Martinez, E.
Cabanas, B.
Ballesteros, B.
Source :
Journal of Atmospheric Chemistry. Sep2001, Vol. 40 Issue 1, p23. 0p.
Publication Year :
2001

Abstract

The absolute rate constants for the gas-phase reactions of the NO3 radical with a series of aldehydes such as acetaldehyde, propanal, butanal, pentanal, hexanal and, heptanal were measured over the temperature range 298-433 K, using a discharge flow system and monitoring the NO3 radical by Laser Induced Fluorescence (LIF). The measured rate constants at 298 K for the reaction of NO3, in units of 10-14 cm3 molecule-1 s-1, were as follows: acetaldehyde 0.32 1 0.04, propanal 0.60 1 0.06, butanal 1.46 1 0.16, pentanal 1.75 1 0.06, hexanal 1.83 1 0.36, and heptanal 2.37 1 0.42. The proposed Arrhenius expressions are k1 = (6.2 1 7.5) x 10-11 exp [?(2826 1 866)/T] (cm3 molecule-1 s-1), k2 = (1.7 1 1.0) x 10-11 exp [?(2250 1 192)/T] (cm3 molecule-1 s1), k3 =(7.6 19.8) x 1011 exp [?(2466 1 505)/T] (cm3 molecule-1 s-1), k4 = (2.8 1 1.4) x 10-11 exp [?(2189 1 156)/T] (cm3 molecule-1s-1), k5 = (7.0 1 1.8) x 10-11 exp [?(2382 1 998)/T] (cm3 molecule-1 s-1), and k6 = (7.8 1 1.0) x 10-11 exp [?(2406 1 481)/T] (cm3 molecule-1 s-1). Tropospheric lifetimes for these aldehydes were calculated at night and during the day for typical NO3 and OH average concentrations and showed that both radicals provide an effective tropospheric sink for these compounds and that the night-time reaction with the NO3 radical can be an important, if not dominant, loss process for these emitted organics and for NO3 radicals. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
01677764
Volume :
40
Issue :
1
Database :
Academic Search Index
Journal :
Journal of Atmospheric Chemistry
Publication Type :
Academic Journal
Accession number :
8436046