Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 10, pp. 1741−1762.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
A.G. Shamov, E.V. Nikolaeva, G.M. Khrapkovskii, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 10, pp. 1587−1608.
STUDIES IN THE FIELD OF CHEMISTRY OF NITRO COMPOUNDS
(TO 100TH BIRTHDAY ANNIVERSARY OF S. S. NOVIKOV)
Primary Steps of the Mechanism of Gas-Phase Monomolecular
Decomposition of Nitropropenes, According to Results
of Quantum-Chemical Calculations
A. G. Shamov, E. V. Nikolaeva, and G. M. Khrapkovskii
Kazan State University of Technology, Kazan, Tatarstan, Russia
Received April 29, 2009
Abstract—The mechanisms of gas-phase monomolecular decomposition of cis- and trans-nitropropenes,
2-nitro-1-propene, and 2-methyl-1-nitro-1-propene were examined by DFT B3LYP/6-31G(d) calculations using
GAUSSIAN’98 program package. The most probable pathway of thermal decomposition of these compounds
involves formation in the primary step of four-membered cyclic intermediates, substituted oxazetes. For cis-
nitropropene and 2-methyl-1-nitro-1-propene, the mechanism whose primary step is 1,5-sigmatropic hydrogen
shift from the CH
group to the NO
group is principally possible.
Much attention has been given recently to studying
the structure and reactivity of nitroolefins, as they
are promising explosives. Therefore, theoretical and
experimental studies on the synthesis and decomposition
of nitroethylene and its substituted derivatives are
performed in Russia and other countries [1–5].
It was found previously [5–8] that thermal mono-
molecular decomposition of nitroethylene (I) occurs
via formation in the limiting step of 4H-1,2-oxazete
2-oxide, rather than via elimination of HNO
in experimental studies (Table 1) . The suggested
mechanism of thermal decomposition of the simplest
representative of nitroolefins is consistent with the
available experimental and theoretical data [9–13]. In
particular, the activation energy of its primary step is close
to the experimental estimate (191.9 kJ mol
Table 1. Activation energies of primary events of thermal monomolecular decomposition of nitroethylene