Decomposition of C-Nitro Compounds. II. Further Studies on Nitroethane

Abstract

The rate constant for the first-order decomposition of nitroethane was found to be represented by k = 1010'83e-39<700 ±207,sz' sec. -I over the temperature range 320-440°. The equation fits data obtained in both static and flow systems, and is consistent with the postulated activated complex having a ring structure. In the range 490-535°a special fast flow system was used and the rate constant given by k = 1017-56e-60'600,ñir _ sec.-1 The activation energy approximates the C-N bond strength at these temperatures and it appears that a non-chain branched mechanism with initial fission of the C-N bond can account for the results at high temperatures.

Sensitizing effects of NOx on CH4 oxidation at high pressure

“…Again, the data were interpreted in terms of a simple Lindemann expression. However, extrapolation of these rate coefficients to lower temperatures (593-715 K and total pressures from 0.1 to 1 bar) provides values somewhat below available measurements [71][72][73][74]. In order to reconcile the data, we have modified the high-pressure limiting rate coefficient k 49,∞ , while retaining k 49,0 from Glänzer and Troe [70].…”

Experimental and Kinetic Modeling Study of Nitroethane Pyrolysis at a Low Pressure: Competition Reactions in the Primary Decomposition

“…studied the pyrolysis of nitromethane, nitroethane, and 1- and 2-nitropropane over the temperature range of 513–1073 K and suggested that the C–N bond fission reaction was also significant. This suggestion was supported by Wilde, who carried out experiments on nitroethane pyrolysis over a wider temperature range . Wilde proposed that C–N bond fission was more important than the CME channel at temperatures higher than 733 K. Since then, a number of studies ,, have confirmed that C–N bond fission dominates at high temperatures because this channel has a higher energy barrier with no apparent transition state.…”

“…This suggestion was supported by Wilde, who carried out experiments on nitroethane pyrolysis over a wider temperature range. 5 Wilde proposed that C−N bond fission was more important than the CME channel at temperatures higher than 733 K. Since then, a number of studies 8,11,12 have confirmed that C−N bond fission dominates at high temperatures because this channel has a higher energy barrier with no apparent transition state. Later, Shaw calculated the activation energy for the CME channel of mononitroalkanes and concluded that the C−N bond rupture was dominant above 770 K. 8 reported a theoretical and experimental study on nitroethane pyrolysis, proposing a simplified mechanism.…”

“…Ever since the first kinetic experimental study on the decomposition of nitro compounds by Talyor and Vesselovsky in 1935, continuous attention has been paid to the decomposition of nitroalkanes − because they are energetic materials that can be used as fuel additives, explosives, and propellants. However, most of these studies focused on nitromethane, while little attention has been paid to nitroethane.…”

“…Most previous studies ,− have suggested that the fission of the C–N bond dominates the primary decomposition of nitromethane because it is the weakest bond in the molecule of nitromethane. In comparison, debate about the primary decomposition of nitroethane remains, despite a number of experimental and theoretical studies aimed at a better understanding of the mechanism of these processes. − ,,, The presence of H atoms on β carbon in the nitroethane molecule enables the decomposition through a concerted molecular elimination (CME) mechanism via a five-membered ring transition state, producing ethylene and HONO. This mechanism was first proposed by Cottrell et al, who performed an experimental investigation on the thermal decomposition of nitroethane and 1-nitropropane in a Pyrex reaction vessel over the temperature range of 628–678 K. The mechanism was confirmed by Spokes and Benson, with an experiment on nitropropane pyrolysis at a very low pressure over the temperature range of 650–1100 K. However, because the C–N bond is the weakest in the nitroethane molecule, which has a bond dissociation energy of 244 kJ/mol compared to 347 kJ/mol of typical C–C bonds, its fission is still important as another important decomposition pathway for nitroethane.…”