The Photochemical Decomposition of Azomethane

The photolysis of azomethane has been investigated over the temperature range 24–190°C. The variation in the rates of production of nitrogen, methane, and ethane with absorbed intensity, azomethane concentration, and temperature may be accounted for quantitatively by the reactions $${\mathrm{CH}}_3\mathrm{N}={\mathrm{NCH}}_3\mathrm{+h\nu \to }{\mathrm{N}}_2\text{+2}{\mathrm{CH}}_3$$ $${\mathrm{CH}}_3+{\mathrm{CH}}_3\mathrm{N}={\mathrm{NCH}}_3\to {\mathrm{CH}}_4+{\mathrm{CH}}_2\mathrm{N}={\mathrm{NCH}}_3$$ $${\mathrm{CH}}_3+{\mathrm{CH}}_3\to {\mathrm{C}}_2{\mathrm{H}}_6.$$ The quantum yield of nitrogen formation was found to be unity and independent of temperature. For the activation energy difference E₂—½E₃ a value of 7.6 kcal/mole was obtained. Evidence is cited for an association reaction between methyl radicals and azomethane. On the basis of an assumed mechanism, the activation energy of this process is 6.4 kcal/mole.