Gas-Phase Reactions of (CH3)2N Radicals with NO and NO2

Article abstract of DOI:10.1021/j100059a022

The absolute rate constants for the reactions of (CH3)2N radicals with NO and NO2 were determined in the gas phase and at room temperature by using the very low pressure reactor (VLPR) technique.The rates were k_{(CH3)2N + NO} = (8.53 +/- 1.42) x 1E-14 Cm³ molecule^-1s^-1 and k_{(CH3)2N + NO2} = (9.08 +/- 1.36) x 1E-13 cm³ molecule^-1s^-1.The reaction with NO2 proceeds via two competitive pathways: the recombination patway (CH3)2N + NO2 -> (CH3)2NNO2, with a rate constant k_2a = (3.18 +/- 0.48) x 1E-13 cm³molecule^-1s^-1, and the oxidation patway (CH3)2N + NO2 -> (CH3)2NONO^* -> (CH3)2NO + NO, with a rate constant k_2b = (6.36 +/- 0.74) x 1E-13 cm³molecule^-1s^-1.The oxidation pathway is ca. 2.2 times faster than the recombination one, and the ratio k_2a/k_2b = 0.45 +/- 0.15.Conventional transition state theory analysis indicates that the involved transition states are loose, with the N<*>N or bond lengths equal to ca. 2.5 Angstroem.