T-Jump/FT-IR Spectroscopy: A New Entry into the Rapid, Isothermal Pyrolysis Chemistry of Solids and Liquids

Abstract

The interface of a Pt filament pyrolysis control unit and a rapid-scan FT-IR spectrometer is described that enables the thermal decomposition of a thin film of material to be studied isothermally after heating at 2000°C/s. A model of the heat transfer of the Pt filament as a function of gas atmosphere and pressure is developed to help understand the instrument response. The control voltage of the Pt filament is highly sensitive to the thermochemistry of the thin film of sample. By simultaneously recording the control voltage and the rapid-scan IR spectra of the near-surface gas products, one learns considerable detail about chemical mechanisms relevant to combustion of a bulk material. The application of T-jump/FT-IR spectroscopy is illustrated with rapid thermolysis data for the energetic organoazide polymers azidomethyl-methyloxetane (AMMO), bis(azidomethyl)oxetane (BAMO), and glycidylazide polymer (GAP); the cyclic nitramine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazacine (HMX); and the nitroaromatic 1,3,5-triamino-2,4,6-trinitrobenzene (TATB).

Syntheses, Structural Characterization and Thermoanalysis of Transition-Metal Compounds Derived from 3,5-Dinitropyridone

“…MnCO 3 , ZnCO 3 and CdCO 3 were of analytical reagent grade and used directly without further purification. All experiments were carried out in twice distilled water.…”

“…In last decades, much attention has been focused on the research of energetic catalysts, which usually contain nitro groups on the molecule, in order to adjust trajectory properties of solid propellants. In the case of energetic catalysts in two-base propellants, metal salts, particularly copper and lead salts, of polynitrophenols [1], picric acids [2][3][4][5][6] and 3-nitro-1,2,4-triazole-5-one (NTO) [7][8][9][10][11][12][13] have been extensively studied. In contrast, few metal salts of polynitropyridone derivatives are investigated and no crystal structures have been reported until we begin to study their molecular structures and thermodecomposition behaviors [14,15], while polynitropyridone derivatives are found themselves in many other applications [16][17][18].…”

Applications of Vibrational Spectroscopy in the Study of Explosives

“…By measuring the temperature dependence of the HCN/NH 3 ratio, it was shown for AMMO that C-N bond retention is favored at higher temperature. 101 More recently, infrared inactive gases have been measured using T-jump/FT-Raman spectroscopy. 118 An interesting example of the T-jump technique applied to molecular crystalline energetic materials involves the Table 7.…”

Flash Pyrolysis Study of M2TNR (M: Carbohydrazide or Semicarbazide) by T‐jump/FTIR Spectroscopy

“…The strategy is to use flash pyrolysis of a thin film of material at a relatively high controllable temperature as a snapshot simulation of the burning surface. 10,11 A reasonably well-defined method is T-jump/FTIR spectroscopy, 12,13 which has played an increased role in the identification of reactants and products, and the measurement of temperature and reaction rates during the thermal decomposition of such materials. The IR-active pyrolysis products and their molar fractions as a function of time are of interest because these products are reactants for the flame zone.…”