Study of the temperature dependence of the reaction of the nitrate radical with propene

Abstract

Rate constants have been determined for the reaction of NO₃ with propene from room temperature up to T= 553 K. Allowance was made in analysing experimental data for probable secondary reactions. The Arrhenius plot shows some curvature at the higher temperatures, which we suggest can be explained by the abstraction of an allylic H atom followed by chain reactions involving fast radical–radical processes. The rate constant at T= 298 K was found to be (0.93 ± 0.12)× 10^–14 cm³ molecule^–1 s^–1. We propose the following Arrhenius expression, in units of cm³ molecule^–1 s^–1, for the addition step in the temperature range T= 298–423 K k=(2.04^+0.78_–0.55)× 10^–13 exp[–(943 ± 108)/T]. For the abstraction reaction of an allylic H atom, we present arguments that suggest Arrhenius parameters of A= 6.8 × 10^–13 cm³ molecule^–1 s^–1 and E= 18 kJ mol^–1.