Atmospheric Chemistry of N-Ch3(ch2)(x)cn (X=0-3): Kinetics and Mechanisms

Smog chamber/Fourier transform infrared (FTIR) techniques were used to measure the kinetics of the reaction of n-CH3(CH2)(x)CN (x=0-3) with Cl atoms and OH radicals: k(CH3CN + Cl)=(1.04 +/- 0.25) x 10(-14), k(CH3CH2CN + Cl)=(9.20 +/- 3.95) x 10(-13), k(CH3(CH2)(2)CN + Cl)=(2.03 +/- 0.23) x 10(-11), k(CH3(CH2)(3)CN + Cl)=(6.70 +/- 0.67) x 10(-11), k(CH3CN + OH)=(4.07 +/- 1.21) x 10(-14), k(CH3CH2CN + OH)=(1.24 +/- 0.27) x 10(-13), k(CH3(CH2)(2)CN + OH)=(4.63 +/- 0.99) x 10(-13), and k(CH3(CH2)(3)CN + OH)=(1.58 +/- 0.38) x 10(-12) cm(3) molecule(-1) s(-1) at a total pressure of 700Torr of air or N-2 diluents at 296 +/- 2K. The atmospheric oxidation of alkyl nitriles proceeds through hydrogen abstraction leading to several carbonyl containing primary oxidation products. HC(O)CN, NCC(O)OONO2, ClC(O)OONO2, and HCN were identified as the main oxidation products from CH3CN, whereas CH3CH2CN gives the products HC(O)CN, CH3C(O)CN, NCC(O)OONO2, and HCN. The oxidation of n-CH3(CH2)(x)CN (x=2-3) leads to a range of oxygenated primary products. Based on the measured OH radical rate constants, the atmospheric lifetimes of n-CH3(CH2)(x)CN (x=0-3) were estimated to be 284, 93, 25, and 7 days for x=0,1, 2, and 3, respectively.