Rk. Talukdar et al., ATMOSPHERIC FATE OF SEVERAL ALKYL NITRATES .1. RATE COEFFICIENTS OF THE REACTIONS ALKYL NITRATES WITH ISOTOPICALLY LABELED HYDROXYL RADICALS, Journal of the Chemical Society. Faraday transactions, 93(16), 1997, pp. 2787-2796
Citations number
30
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The rate coefficients for the reaction of OH radical with CH3ONO2 (k(1
)), CD3ONO2 (k(6)), C2H5ONO, (k(2)) and 2-C3H7ONO2 (k(3)) between 220
and 410 K were measured to be: k(1) = (8.2 +/- 1.6) x 10(-13) exp{-(10
20 +/- 60)/T}, k(6) = (1.6 +/- 0.2)(8.2 +/- 1.6) x 10(-13) exp{-(1020
+/- 60)/T}, k(6) = (1.6 +/- 0.2) x 10(-12) exp{-(1730 +/- 40)/T}, k(2)
=3.68 x 10(-12) exp(-1077/T) + 5.32 x 10(-14) exp(126/T) and k(3)=4.3
x 10(-12) exp(-1250/T) + 2.5 x 10(-13) exp(-32/T) cm(3) molecule(-1)s(
-1). The quoted errors in the Arrhenius expressions are at the 95% con
fidence limit and include estimated systematic errors. The measured ra
te coefficients for the reactions of (OH)-O-18 were roughly the same a
s those for (OH)-O-16 reactions while the rate constants for OD reacti
ons were slightly (ca. 10-15%) higher than those for OH reactions. The
hydroxyl radicals were generated by pulsed laser photolysis and detec
ted by pulsed laser induced fluorescence. The observed large primary k
inetic isotope effect(k(1)/k(6) = 4.5 at 298 K), the independence of t
he measured rate coefficients on the gas composition, and the trend in
the reactivity with the alkyl group suggests that the above reactions
proceed via abstraction of an H atom from the alkyl group. Our result
s are compared with those from previous studies.