Gy. Adusei et A. Fontijn, COMPARISON OF THE KINETICS OF O(P-3) REACTIONS WITH THE 4 BUTENES OVER WIDE TEMPERATURE RANGES, Journal of physical chemistry, 98(14), 1994, pp. 3732-3739
Rate coefficients for reactions of ground-state oxygen atoms with isob
utene, trans-2-butene, and cis-2-butene have been measured using the h
igh-temperature photochemistry (HTP) technique. The oxygen atoms were
generated by flash photolysis of either O-2 or CO2 and the relative at
om concentrations were monitored by resonance fluorescence. We find, i
n cm(3) molecule(-1) s(-1) units, for isobutene, k(284-1015 K) = 2.0 x
10(-15). (T/K)(1.28) exp(543 K/T); trans-2-butene, k(292-1022 K) = 3.
9 X 10(-17)(T/K)(1.87) exp(743 K/T); and cis-2-butene, k(292-1086 K) =
2.4 X 10(-17)(T/K)(1.94) exp(716 K/T). The 2 sigma precision limits a
re around +/-10%, and the corresponding 2 sigma accuracy limits are es
timated to be about +/-25%. Conventional transition-state-theory calcu
lations for the electrophilic O-addition to the double bond yield at h
igh temperatures rate coefficients smaller than observed. A method is
developed for estimating rate coefficients for H abstraction. When the
results are added to those of the addition, good agreement with exper
iments is attained. The differences between the k(T) expressions for t
he present three reactions and the corresponding 1-butene reaction are
discussed in terms of the electronic effects of alkyl substituents on
the double bond, and the greater curvature of the addition reaction A
rrhenius plot and faster H abstraction for 1-butene. Based on these ob
servations, a method is presented for estimating rate coefficients for
O-atom reactions with higher olefins over wide temperature ranges.