An absolute measurement of the rate constant for ethyl radical combination

Abstract

An absolute value of k, of ethyl radicals at 860 f 17°K of 4.5 X l o 9 M-l.sec-' was determined under VLPP conditions, where the value of k,/k," should be about M. Thus k,"(M-'.sec-')

An absolute measurement of the rate constant for t‐butyl radical combination

“…Values for that rate constant determined by the present method [15] are about log k:t_hl M-'.sec-' = 10 at 850°K. Since the HB experimental conditions should correspond to the high-pressure value for ethyl recombination, the value in Table VII implies that log k:-butyl (M-I-sec-') = 9.4 at 373"K, which is 1.2 orders of magnitude greater than the value predicted in Table VI and about a factor of five greater than the value reported here.…”

The kinetics and mechanism of n‐butyraldehyde photolysis in the vapor phase at 313 nm

“…From the plot of log(ks/k11/2) versus 1/T a good straight line is obtained, from which log(ktJk11/2) = (3.1 f 0.3) -(6600 f 500)/2.303 RT. Estimating log kl(dm3/mol.sec) = log A1 = 9.8 on the basis of the rate constant obtained for ethyl recombination [14] and reported for ethyl [15] and isopropyl [15] self-combination, one obtains Hydrogen atom abstraction from the a-carbon atom of the alkyl chain of the aldehyde [reaction (9)] is shown to occur by the formation of the combination product C3H7CH(C2H&HO at low temperatures and by the strong increase of the methane yield due to decomposition (19) at high temperatures. The kg/k11/2 ratio may be obtained from the equation…”

On the reactivity of diethyl hydroxyl amine toward free radicals

“…A reaction scheme comprising reactions k2Jk31/2 = 36 f 4 M-lI2 sec-l and since k3 can be taken as 8 X 109 M-l-sec-l [8], i t can be found that k2 = 3 f 0.7 X lo6 M-l-sec-l. A similar value was obtained employing isopropyl radicals. The value of kz obtained is considerably higher than those reported for the reaction of methyl radicals and the methylene group in ethyl amines [9], and suggests that the reaction involves abstraction from the hydroxylic hydrogen.…”

“…Under atmospheric ( 8 ) CH30-+ DEHA + CH30H + Xwill compete efficiently with reaction (7) only if hs is higher than 1OI2 M-l-sec-'. This seems an almost impossibly high value for a bimolecular reaction involving two polyatomic molecules.…”