Magic of Numbers: A Guide for Preliminary Estimation of the Detonation Performance of C-H-N-O Explosives Based on Empirical Formulas

Abstract

In this paper, we report a comprehensive analytical study of the factors influencing the detonation properties of C-H-N-O explosives. Besides the commonly applied parameters, namely, solid-state enthalpy of formation (Î"Hf) and crystal density (dc), for which simple zeroth-order additive models based on the atomic increments are developed in this work, we also consider compositional factor being an intrinsic characteristic of each single empirical formula. Using a wide number of reference molecules (320 for Î"Hf and 360 for dc), we have developed empirical equations, which provide rather good correlation coefficients R2 = 0.90 and 0.80 for Î"Hf and dc, respectively. Knowing these two equations and empirical formula, one can predict the detonation properties of a C-H-N-O explosive using a pocket calculator. Of course, such an approach, which completely neglects chemical structure, can be applied mainly for structurally similar compounds. However, having significant differences between the predicted detonation properties of two compositions, the account of their exact structures cannot reorder the predicted values. Thus, this paper can be used as a simple guide for molecular engineering and explosive structure enhancement. For this purpose, we provide a list of all compositions with the predicted properties up to C30H30N30O30 in the Supporting Information. To demonstrate how it works, we have applied the developed approach along with quantum-chemical calculations to model chemical structures outperforming ϵ-hexanitrohexaazaisowurtzitane (the most powerful explosive) in detonation performance.