Structure‐Activity Relationship Analysis of the Thermal Stabilities of Nitroaromatic Compounds Following Different Decomposition Mechanisms

Abstract

The decomposition behavior of energetic materials is very important for the safety problems concerning their production, transportation, use and storage, because molecular decomposition is intimately connected to their explosive properties. Nitroaromatic compounds, particularly nitrobenzene derivatives, are often considered as prototypical energetic molecules, and some of them are commonly used as high explosives. Quantitative structure-activity relationship (QSAR) represents a potential tool for predicting the thermal stability properties of energetic materials. But it is reported that constructing general reliable models to predict their stability and their potential explosive properties is a very difficult task. In this work, we make our efforts to investigate the relationship between the molecular structures and corresponding thermal stabilities of 77 nitrobenzene derivatives with various substituent functional groups (in ortho, meta and/or para positions). The proposed best MLR model, developed by the new software QSARINS, based on Genetic Algorithm for variable selection and with various validation tools, is robust, stable and predictive with R(2) of 0.86, QLOO (2) of 0.79 and CCC of 0.90. The results indicated that, though difficult, it is possible to build predictive, externally validated QSAR models to estimate the thermal stability of nitroaromatic compounds.

Significance of Theoretical Decomposition Enthalpies for Predicting Thermal Hazards

“…Present results demonstrate that the present approach makes it straightforward to derive predictive tools performing similarly or even better than the best QSPR methods at hand, provided PH data for ortho compounds are excluded from the data set. Whenever these difficult cases are considered, present equations fail to provide meaningful predictions, while the most successful QSPR studies appear to succeed in obtaining fairly reasonable results, especially for the seven-parameters model put forward very recently in [15].…”

“…Most modeling studies focus on the SC data set [8][9][10][11][12]. Only very recent ones take advantage of the PH data set [13,15]. Both SC and PH data sets are considered in the present work.…”

“…Although they do rely on such techniques, presently published models apply them directly to the evaluation of Δ (DSC) in terms of standard descriptors [7][8][9][10][11][12][13][14][15]. As a result, they do not take advantage of the availability of simple rules to estimate decomposition products and corresponding Δ 0 values [16].…”