Thermal decomposition - gas phase

Carrington and Davidson subjected a mixture of N2O4, and NO2 to a weak shock wave. The resultant adiabatic compression produced a rise in temperature and the rate of attainment of equilibrium at the new temperature was measured photochemically. All experiments were made with a large excess of nitrogen or carbon dioxide (0.5-7 atm). When the nitrogen pressure was below 1 atm second-order kinetics were observed such that 

The authors estimate their mean deviation in the experiments as 15 %. 

More recently, Cher has studied the reaction by ultrasonic absorption measurements and the results substantiate those of Carrington and Davidson. 

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