Rate constants for the reactions of OH with CH[sub 3]Cl, CH[sub 2]Cl[sub 2], CHCl[sub 3], and CH[sub 3]Br

Journal Article · Sun May 01 04:00:00 EDT 1994 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/94GL00601· OSTI ID:6612787

Hsu, K J; DeMore, W B ^[1]

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1. California Institute of Technology, Pasadena (United States)

Rate constants for the reaction of OH with CH[sub 3]Cl, CH[sub 2]Cl[sub 2], CHCl[sub 3], and CH[sub 3]Br have been measured by a relative rate technique in which the reaction rate of each compound was compared to that of HFC-152a (CH[sub 3]CHF[sub 2]) and (for CH[sub 2]Cl[sub 2]) HFC-161 (CH[sub 3]CH[sub 2]F). Using absolute rate constants for HFC-152 and HFC-161, which they have determined relative to those for CH[sub 4], CH[sub 3]CCl[sub 3], and C[sub 2]H[sub 6], temperature dependent rate constants of both compounds were derived. The derived rate constant for CH[sub 3]Br is in good agreement with recent absolute measurements. However, for the chloromethanes all the rate constants are lower at atmospheric temperatures than previously reported, especially for CH[sub 2]Cl[sub 2] where the present rate constant is about a factor of 1.6 below the JPL 92-20 value. The new rate constant appears to resolve a discrepancy between the observed atmospheric concentrations and those calculated from the previous rate constant and estimated release rates. 23 refs., 5 figs., 3 tabs.

• OSTI ID: 6612787
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Journal Name: Geophysical Research Letters (American Geophysical Union); (United States) Vol. 21:9; ISSN GPRLAJ; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
BROMINATED ALIPHATIC HYDROCARBONS
CHEMICAL REACTION KINETICS
CHLORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROXYL RADICALS
KINETICS
METHYL BROMIDE
METHYL CHLORIDE
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
RADICALS
REACTION KINETICS