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X‐ray diffraction spectroscopic and thermal studies on 1,3,5‐trinitro‐hexahydropyrimidine (TNP)
Author(s) -
Prabhakaran K. V.,
Naidu S. R.,
Kurian E. M.
Publication year - 1995
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19950200504
Subject(s) - differential scanning calorimetry , thermogravimetry , thermal decomposition , induction period , activation energy , isothermal process , infrared spectroscopy , analytical chemistry (journal) , differential thermal analysis , chemistry , thermal analysis , powder diffraction , infrared , crystallography , diffraction , thermal , organic chemistry , inorganic chemistry , thermodynamics , catalysis , physics , optics
TNP, a heterocyclic nitramine containing a CNO 2 functionality, has been studied as regards the kinetics and mechanism of thermal decomposition, morphology and the gaseous products evolved therof, using thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR), differential scanning calorimetry (DSC), X‐ray diffraction (XRD) and hot stage microscopy. The elementary cell parameters obtained form the XRD pattern are: a = 18.818 ± 0.005 Å, b = 18.818 ± 0.005 Å and c = 4.867 ± 0.005 Å. The crystal belongs to the hexagonal system with c/a ratio = 0.259. IR spectra of TNP have also been recorded and the bands assigned. Kinetics of thermolysis has been followed both by isothermal TG and IR. The best linearity with a correlation coefficient of 0.986 was obtained for the three‐dimensional diffusion controlled Jander‐equation. Kinetic parameters were evaluated from the induction period as well as from isothermal TG. Activation energy was found to be 202.05 kJ/mol and log A(in s‐ 1 ) 22.78 from TG and 181.133 kJ/mol and log A (in s 1 ) 20.97 from IR, respectively. The corresponding values were 171.17 kJ/mol and log A (in s‐ 1 ) 21.20 from the induction period data. The effect of a series of additives incorporated to the extent of 5 %, on the initial thermolysis of TNP, has also been studied. Evolved gas analysis by IR showed that CO 2 , NO 2 , NO and N 2 O are produced in larger amounts than CO and HCN. The cleavage of the NN bond appears to be the primary step in the thermolysis of TNP.