Thermal dissociation of nitromethane
Argonne Chemical Sciences and Engineering division researchers Lawrence B. Harding, Stephen J. Klippenstein, John B. Randazzo, Branko Ruscic and Robert S. Tranter are exploring the thermal dissociation and roaming isomerization of nitromethane.
The thermal decomposition of nitromethane provides a classic example of the competition between roaming mediated isomerization and simple bond fission. A recent theoretical analysis suggests that as the pressure is increased from 2 to 200 Torr the product distribution undergoes a sharp transition from roaming dominated to bond-fission dominated. Laser schlieren densitometry is used to explore the variation in the effect of roaming on the density gradients for CH3NO2 decomposition in a shock tube for pressures of 30, 60, and 120 Torr at temperatures ranging from 1200 to 1860 K. A complementary theoretical analysis provides a novel exploration of the effects of roaming on the thermal decomposition kinetics. The analysis focuses on the roaming dynamics in a reduced dimensional space consisting of the rigid-body motions of the CH3 and NO2 radicals.
Lawrence B. Harding, Stephen J. Klippenstein, John B. Randazzo, Branko Ruscic and Robert S. Tranter, “Thermal Dissociation and Roaming Isomerization of Nitromethane: Experiment and Theory,” The Journal of Physical Chemistry A, Article ASAP, DOI: 10.1021/acs.jpca.5b01563, Published April 17, 2015.