Kinetics and mechanism of thermal decomposition of bis-$\mathrm{R}$-substituted gem-dinitroethyl-$\mathrm{N}$-nitramines

The thermal decomposition of bis-$\mathrm{R}$-substituted gem-dinitroethyl-$\mathrm{N}$-nitramines in diphenyl ether solution was studied by a manometric method in combination with mass spectrometry and photoelectric colorimetry. The reaction proceeds according to the first order equation and is not complicated by chain and heterogeneous processes. The rate-determining step of the process is the homolysis of the $\mathrm{C}$–$\mathrm{NO}_2$ bond in the gem-dinitro group. The kinetic parameters of the rate-determining step were determined. The influence of the structure on the reactivity of the investigated compounds was analyzed. Linear relationships were found between the rate constant, the activation energy of thermal decomposition, and the steric constants of the $\alpha$-substituent of the reaction center.