The oxidation of methyl radicals at room temperature

Using the technique of molecular modulation spectrometry, we have measured directly the rate constants of several reactions involved in the oxidation of methyl radicals at room temperature:k 1 is in the fall‐off pressure regime at our experimental pressures (20–760 torr) where the order lies between second and third and we obtain an estimate for the second‐orderlimit of (1.2 ± 0.6) × 10 −12 cm 3 /molec · sec, together with third‐order rate constants of (3.1 ± 0.8) × 10 −31 cm 6 /molec 2 · sec with N 2 as third body and (1.5 ± 0.8) × 10 −30 with neopentane;we cannot differentiate between k 2a and k 2c and we conclude k 2a + ( k 2c ) = (3.05 ± 0.8) × 10 −13 cm 3 /molec · sec and k 2b = (1.6 ± 0.4) × 10 −13 cm 3 /molec · sec;k 3 = (6.0 ± 1.0) × 10 −11 cm 3 /molec · sec.