Kinetics of the reaction of N(4S) with isobutane

Abstract

The kinetics of the reaction of isobutane with N(⁴S) have been studied as a function of reactant concentration and temperature from 300 to 550 K. The initial rate of consumption of N(⁴S) was second order in N(⁴S) and first order in isobutane. The initiation step which best describes the results is N + N + i-C₄H₁₀→ N₂+ CH₃+ 2-C₂H₇ and its rate constant fits the expression k= 2.26 × 10¹⁷ exp(–3890/T) dm⁶ mol^–2 s^–1 A mechanism is proposed for the reaction which quantitatively accounts for the consumption of N(⁴S) and the production of HCN as a function of both temperature and time. HCN arises in this mechanism from reactions of N(⁴S) with CH₃, 2-C₃H₇ and other alkyl radicals formed in subsequent reactions.