Reactions of O2+, NO+ and H3O+ with methylcyclohexane (C7H14) and cyclooctane (C8H16) from 298 to 700 K

Rate constants and branching fractions have been measured as a function of temperature for the reactions Of O-2(+), NO+ and H3O+ with methylcyclohexane (C7H14) and cyclooctane (C8H16) using fast flow tube methods. The reactions of O-2(+) with both cyclic molecules proceed via non-dissociative and dissociative charge transfer at the capture collision rate from 298 to 700 K. From 298 to 500 K, NO+ reacts with the two neutral reagents via non-dissociative hydride transfer, and from 500 to 700 K, an increasing fraction of the reaction products are due to dissociative hydride transfer. The rate constants for NO+ reacting with both C7H14 and C8H16 equal the capture collision rate constants at all temperatures. The H3O+ reactions proceed at less than or equal to38% and less than or equal to22% of the capture collision rate with C7H14 and C8H16, respectively. The rate constants display a negative temperature dependence with both reagents from 298 to 500 K. Reaction products observed in the H3O+ reactions include association, non-dissociative proton transfer and dissociative proton transfer. Increasing amounts of the dissociation products are observed at higher temperatures.