ISSN:
1573-0662
Keywords:
Hydroxyl radical
;
halon
;
rate constant
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Geosciences
Notes:
Abstract Rate constants have been measured for the gas-phase reactions of hydroxyl radical with two halons and three of their proposed substitutes and also with CHClBr-CF3 using the discharge-flow-EPR technique over the temperature range 298–460 K. The following Arrhenius expressions have been derived (units are 10−13 cm3 molecule−1 s−1): (9.3 −0.9 +1.0 ) exp{−(1326±33)/T} for CHF2Br; (7.2 −0.6 +0.7 ) exp{−(1111±32)/T} for CHFBrCF3; (8.5 −0.8 +0.9 ) exp{−(1113±35)/T} for CH2BrCF3; (12.8 −1.2 +1.5 ) exp{−(995±38)/T} for CHClBrCF3. The rate constants at 298 K have been estimated to be 〈2×10−17 cm3 molecule−1 s−1 for CF3Br and CF2Br—CF2Br. The atmospheric lifetimes due to hydroxyl attack have been estimated to be 5.5, 3.3, 2.8, and 1.2 years for CHF2Br, CHFBr—CF3, CH2Br—CF3 and CHClBr—CF3, respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00702786
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