Spectro-thermal decomposition study of 1,4-dinitroglycoluril (DINGU)

Abstract

Simultaneous thermal analysis and high temperature FTIR study of 1,4-dinitroglycoluril (DINGU) is reported. TG showed 90% weight loss in the temperature range 225–250 °C. Isothermal TG of DINGU showed about 70% weight loss in the temperature range 210–230 °C. Kinetic parameters evaluated using a computer program showed that α– t data are best described by the Avrami–Erofeev's equation for n = 2 with an activation energy of 165 kJ/mol. The kinetics of decomposition of DINGU was followed by studying N H (3388 cm −1), C O (1770–1810 cm −1) and NO 2 symmetric stretching (1565–1570 cm −1) IR bands. All three bands showed loss of intensity with temperature and time. α– t data of decomposition with respect to NO 2 stretching was again best described by the Avrami–Erofeev's equation for n = 2. Gaseous decomposition products observed in the IR were N 2O, NO 2, CO 2, HCN and NO. PM3 and Hartree–Fock level calculations on various bond lengths, bond angles and dihedral angles were computed to support the analysis of decomposition study using TG and IR. The data showed that C N and N H bonds are much shorter than the N N bonds, indicative of the weaker N N bond and hence, the possibilities of rupture of the same bond preferentially. This paper also discusses the sensitivity and performance properties of DINGU.