Kinetics of CCN Radical Reactions with a Series of Normal Alkanes

The reactions of CCN(X2Πi) radicals with normal alkanes have been studied at about 10 Torr total pressure and room temperature using the pulse laser photolysis/laser-induced fluorescence technique. CCN (X2Πi) radicals are generated by the fourth harmonic of a Nd:YAG laser photolysis of Cl3CCN at 266 nm. The relative concentration of CCN (X2Πi) radicals was monitored in the (0−0) band of the CCN (A2Δ ← X2Πi) transition at 470.9 nm by laser induced fluorescence (LIF). From the analysis of the relative concentration−time behavior of CCN (X2Πi) under pseudo-first-order conditions, the rate constants for the reaction of CCN (X2Πi) with a series of normal alkanes (C1−C8) were determined for the first time. The new data establish that the gas-phase reactivity of small alkanes (C1−C8) towards the CCN radicals follows the linear free energy relationship typical of hydrogen abstraction. A comparison with the corresponding reactions of CN and OH radicals with a series of normal alkanes, leads us to suggest tha...