Reaction between OH and HCHO: temperature dependent rate coefficients (202–399 K) and product pathways (298 K)

Autor:	John Crowley, V. Sivakumaran, Terry J. Dillon, Dirk Hölscher
Rok vydání:	2003
Předmět:	Troposphere chemistry.chemical_compound Reaction mechanism Reaction rate constant chemistry Analytical chemistry Formaldehyde Fluorescence spectrometry General Physics and Astronomy Free-radical reaction Physical and Theoretical Chemistry Atmospheric temperature range Laser-induced fluorescence
Zdroj:	Phys. Chem. Chem. Phys.. 5:4821-4827
ISSN:	1463-9084 1463-9076
DOI:	10.1039/b306859e
Popis:	Absolute rate coefficients for the title reaction, OH + HCHO → products (R1) were measured over the temperature range 202–399 K using the technique of pulsed laser photolytic generation of OH radical coupled to detection by pulsed laser induced fluorescence. The accuracy of the rate constants obtained was enhanced by on-line optical absorption measurements of the formaldehyde concentration. The temperature dependence of the rate coefficient is given by: k1(202–399 K) = 9.52 × 10−18T2.03 exp{636/T} cm3 molecule−1 s−1 with the rate coefficient at room temperature of 8.46 × 10−12 cm3 molecule−1 s−1. The estimated total error (95% confidence) associated with the rate coefficient derived from this expression is estimated as 5% close to 300 K, increasing to 7% at the extremes of the temperature range covered. The present results, which extend the database on this reaction to cover temperatures relevant for the upper troposphere, are compared to previously published measurements, and values of k1 for atmospheric modelling are recommended. In accord with most previous studies, we find no evidence for H atom formation in (R1).
Databáze:	OpenAIRE
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