X-ray diffraction, thermal and spectroscopic studies on 2,4-dinitrodiphenylamine (DNDPA)

2,4-Dinitrodiphenylamine (DNDPA) has been studied as regards its crystal st ructure and thermal decomposition characteristics using X-ray diffraction ( XRD), simultaneous thermal analysis, ultraviolet and Visible spectroscopy, infrared spectroscopy, hot-stage microscopy and high performance liquid chr omatography (HPLC). The elementary cell parameters obtained from the XRD pa ttern are a=17.002 Angstrom, b = 17.002 Angstrom, c = 20.400 Angstrom. The crystal structure belongs to the hexagonal system with c/a ratio 1.1999. IR spectra of 2,4-DNDPA have also been recorded and the bands assigned. Kinet ics of thermolysis has been followed both by isothermal thermogravimetry (T G) and HPLC. The best linearity with a correlation coefficient of 0.994 was obtained for the two-dimensional diffusion controlled equation in TG. Acti vation energy was found to be 83.0 kJ/mol and log A (in s(-1) = 6.0 from is othermal TG. The rupture of the C-NH bond followed by the C-NO2 bond consti tutes the primary step in the thermolysis and the decomposition is free-rad ical assisted.