Theoretical Research on Cage-like Oxadiazole-based Energetic Compounds and Its Derivatives

In this manuscript, we reported the design and prediction of two oxadiazole-based cage-like molecules and their derivatives using density function theory (DFT). The heats formation and detonation properties were calculated using Hess’s law and Kamlet-Jacobs equations with B3PW91 method. The molecular stability and geometry were analyzed using M06-2X method and molecular crystal structures were predicted based on Monte Carlo simulation, while chemical reactive sites were judged using PBE0 method based on Fukui function. The theoretical calculation result proved that the designed molecules exhibit ideal symmetric cage-like geometry and show superior physicochemical and detonation properties. Compared with traditional energetic materials, the designed molecules display more positive solid heats formation and lower sensitivity. The designed molecules could be considered as promising HEDM candidates with potential synthesis and application value.

Enthalpy and thermochemistry

Definition and mathematics of enthalpy. Definition of heat capacity at constant pressure as CP = (∂H/∂T)V. Endothermic and exothermic reactions. Role of the change in enthalpy as regards the direction and spontaneity of a change in state. Enthalpy changes and phase changes. Measuring enthalpy changes by calorimetry. Hess’s law of constant heat formation. Chemical standards and standard states. Standard enthalpies of formation, ionic enthalpies and bond energies. How the change in enthalpy varies with temperature. Kirchhoff’s equations. Applications of thermochemistry to a variety of worked examples, including flames and explosions.

Synthesis and Standard Molar Formation Enthalpy of Plate Shape NaZnPO4·H2O

Plate shape NaZnPO4·H2O was synthesized by solid-state reaction at low temperature and characterized by X-Ray Diffraction, Scanning electron microscope and elemental analysis. Thermochemical study was performed with an isoperibol solution calorimeter. Based on Hess’s law, thermochemical cycl was designed to determine the dissolution enthalpies of reactants and products using a solution-reaction isoperibol calorimeter at 298.15 K, and the molar reaction enthalpy was calculated on the basis of above dissolution enthalpies. The results show that the obtained product is plate shape NaZnPO4·H2O. The standard molar formation enthalpy of the NaZnPO4·H2O is ΔfHm [NaZnPO4·H2O,s]= -1967.18 ± 0.69 kJ•mol-1.