The Polymorphism of 2,2-Dinitropropyl 4,4,4-Trinitrobutyrate

Abstract

Properties of three crystallographic modifications of 2,2-dinitropropyl 4,4,4-trinitrobutyrate are reported. The polymorphic system is represented by a phase diagram which includes two enantiotropic transitions: I → II at 11 4° and II → at 62.5°C and the melting point, 95.0°C, possesses most of the properties of the plastic crystalline state including a low entropy of fusion, 4.5 e.u. Althought the 2,2-dinitropropyl 4,4,4-trinitrobutyrae molecule does not have spherical symmetry, the low entropy of fusion is evidence of considerable orientational disorder in the lattice of the hight temperature form. A differential scanning calorimeter was used to determine heats of transition: I → III = 6.2 kcal/mole; II → III = 5.0 kcal/mole.