The crystal structure and thermal decomposition kinetics of cis-hexanitrostilbene

Abstract

Hexanitrostilbene (HNS) is an energetic material with wide application and excellent comprehensive performance. cis-HNS is successfully prepared using crude HNS with a purity of 95% as the raw material and N-methyl pyrrolidone (NMP) as the solvent. After separation and purification, acetone is used as a solvent to obtain light-yellow crystals at room temperature. The molecular structure of cis-HNS is determined through analysis of Fourier transform infrared, 13C NMR and 1H NMR spectroscopy and single-crystal X-ray diffraction data. The thermal decomposition properties of cis and trans-HNS are studied using differential scanning calorimetry (DSC). When the heating rate is low, cis-HNS will undergo a crystal transformation after melting, from liquid cis-HNS to liquid trans-HNS, and then it will solidify and release heat. According to the results of DSC data, the apparent kinetic parameters of thermal decomposition of cis- and trans-HNS were obtained by Kissinger method [Kissinger (1957). Anal. Chem. 29, 1702–1706] and Ozawa method [Ozawa (1965). Bull. Chem. Soc. Jpn. 38, 1881–1886], respectively. The spontaneous combustion temperature and self-accelerating decomposition temperature of cis and trans-HNS are calculated by the Zhang-Hu-Xie-Li method [Zhang et al. (1994). Thermochim. Acta, 244, 171–176].