Thermal decomposition of methyl nitrite in shock waves studied by laser probing

The unimolecular decomposition of methyl nitrite in the temperature range 680–955 K and pressure range 0.64 to 2.0 atm has been studied in shock‐tube experiments employing real‐time absorption of CW CO laser radiation by the NO product. Computer kinetic modeling using a set of 23 reactions shows that NO product is relatively unreactive. Its initial rate of production can be used to yield directly the unimolecular rate constant, which in the fall‐off region, can be represented by the second‐order rate coefficient in the Arrhenius form: (Formula Presented.) A RRKM model calculation, assuming a loose CH₃ONO^≠ complex with two degrees of free internal rotation, gives good agreement with the experimental rate constants.