Topological pressure-temperature state diagram of the crystalline dimorphism of 2,4,6-trinitrotoluene

Abstract

The phase behavior of explosive substances is important for the proper design of stable explosive devices. However, the equilibrium behavior of chemical compounds can be difficult to assess, because thermodynamic and kinetic behaviors are generally convoluted in the experimental results. The phase behavior of TNT is a case in point. A thorough review of the literature data demonstrates that the orthorhombic polymorph is the most stable under ambient conditions. Using the topological approach for the construction of a pressure-temperature phase diagram, it can be shown that all data is consistent with an overall enantiotropic system. Nonetheless, it is also clear that the differences between the orthorhombic and the monoclinic polymorphs are relatively small and that the driving force of interconversion between the two under ambient conditions is therefore limited.

Crystalline tetrazepam as a case study on the volume change on melting of molecular organic compounds

“…It results in vL,fus (T = 415.6 K) = 0.847(5) cm 3 g -1 and the ratio vL/vS at Tfus equals therefore 1.089(6), i.e. close to the value of 1.11 ±0.04, previously found for a number of molecular compounds (Barrio et al, 2019;Ceolin and Rietveld, 2017;Céolin and Rietveld, 2015;Céolin and Rietveld, 2020;Rietveld and Céolin, 2015). ρL at the melting triple point Tt (Goodman et al, 2004).…”

Crystal Structure of Polymorph II and the Pressure–Temperature Phase Diagram of the Dimorphic Anesthetic Butamben

“…It demonstrates once more that, with the Clapeyron equation, data obtained at ordinary pressure can be used to construct a realistic topological pressure–temperature phase diagram and to determine the overall phase behavior in terms of the four cases of dimorphism described by Bakhuis Roozeboom. Similar phase diagrams can also be found in some recently studied cases: benzylthiouracil, trinitrotoluene, and nimesulide …”

Glycine: The Gift that Keeps on Giving

“…As when comparing the relative thermodynamic stabilities of glycine polymorphs at ambient pressure, a reliable answer on the relative stabilities at high pressures could be given by high-pressure calorimetry. Examples of such studies for several compounds are known, [117][118][119][120][121][122][123][124][125][126] but not for glycine (yet? ).…”