Mechanism of thermolysis of hydroxylamino-dinitroethylenes

Promising energetic materials—1,1-diamino-2,2-dinitroethylene (DADNE) derivatives in which one or both hydrogen atoms of the amino group are substituted by the OH group were studied by quantum chemical methods using PBE0 hybrid functional with the cc-pVDZ basis set and the coupled cluster method on the CCSD/aug-cc-pVDZ level. A series of primary steps of thermolysis were studied, and it has been shown that introduction of the hydroxyl group leads to a change in the mechanism of the rate-determining step. In contrast to the DADNE, for hydroxyl derivatives a number of additional reactions involving the hydroxyl group are possible and the rate-determining stage of thermolysis is the reaction of transfer of the H atom from -OH group to a carbon atom. At the same time, the activation enthalpy decreases sharply from 200 for DADNE to 110 kJ mol–1 for mono- and 90 kJ mol–1 for disubstituted DADNE.