Kinetics of addition of methyl and ethyl radicals to nitric oxide

Abstract

The rates of addition of methyl and ethyl radicals to nitric oxide have been studied in a fast flow discharge tube at 8 Torr (1 Torr = 133 N m^–2) pressure in excess helium over a range of temperatures 325–521 K. The reaction of methyl is close to third order with log₁₀(k/dm⁶ mol^–2 s^–1)= 10.86 ± 0.08 +(420 ± 20)/4.5757(T/K). The reaction of ethyl is close to second order with k=(1.4 ± 0.2)× 10⁸ dm³ mol^–1 s^–1 independent of temperature. RRKM calculated fall-off curves were used with these rate constants to show that the addition of ethyl is substantially slower than that of methyl at the high pressure limit.