THERMAL DECOMPOSITION OF GASEOUS AMMONIUM DINITRAMIDE AT LOW PRESSURE: KINETIC MODELING OF PRODUCT FORMATION WITH ab initio MO/cVRRKM CALCULATIONS
نویسنده
چکیده
The thermal decomposition of ammonium dinitramide, NH4N(NO2)2 (ADN), in the gas phase has been studied at 373–920 K by pyrolysis/mass spectrometry under low-pressure conditions using a Saalfeld reactor. The reaction of the sublimed mixture of NH3 and HN(NO2)2 (dinitraminic acid, DN) was found to be initiated by the unimolecular decomposition of DN, HN(NO2)2 → HNNO2 ` NO2, followed by the rapid decomposition reaction, HNNO2 ` M → N2O ` OH ` M. The measured absolute yields of NH3, H2O, N2, and N2O, calibrated with standard mixtures, could be satisfactorily modeled at 10 Torr He carrier gas pressure by employing the theoretically computed values of k2 4 6.79 2 1048 T111.0 exp(121780/T) s11 and k3 4 7.53 2 1024 T12.9 exp(112958/T) cm3/(mol s) by high-level ab initio molecular orbital and canonical variational Rice-Ramsperger-Kassel-Marcus (MO/cVRRKM) calculations. The key reactions with recommended rate constants are presented.
منابع مشابه
Kinetic stability and propellant performance of green energetic materials.
A thorough theoretical investigation of four promising green energetic materials is presented. The kinetic stability of the dinitramide, trinitrogen dioxide, pentazole, and oxopentazole anions has been evaluated in the gas phase and in solution by using high-level ab initio and DFT calculations. Theoretical UV spectra, solid-state heats of formation, density, as well as propellant performance f...
متن کاملKinetic analysis of overlapping multistep thermal decomposition comprising exothermic and endothermic processes: thermolysis of ammonium dinitramide.
This study focused on kinetic modeling of a specific type of multistep heterogeneous reaction comprising exothermic and endothermic reaction steps, as exemplified by the practical kinetic analysis of the experimental kinetic curves for the thermal decomposition of molten ammonium dinitramide (ADN). It is known that the thermal decomposition of ADN occurs as a consecutive two step mass-loss proc...
متن کاملAn Ab Initio SCF-MO Study of Conformational Properties of (Z)- Cyclooctene
Ab initio calculations at HF/6-31G* level of theory for geometry optimization and MP2/6-31G*//HF/6-31G*for total energy calculation are reported for Z-cyclooctene (1). The most favorable conformation of 1 is theunsymmetric boat-chair (1-BC) geometry. Potential energy profiles for two different boat-chair/boat-chairinterconversion processes were calculated. The process via a chair transition sta...
متن کاملKinetic Modeling of the Gas Phase Decomposition of Germane by Computational Chemistry Techniques
Very limited experimental data are available on thermal decomposition of germane in the gas phase. Recent developments in theoretical quantum chemistry techniques such as ab initio Hartree-Fock and density functional methods have made accurate determination of molecular properties possible. Systematic development of a detailed gas-phase decomposition mechanism for germane using ab initio molecu...
متن کاملAb Initio MO Study of the Unimolecular Decomposition of the Phenyl Radical
The unimolecular decomposition of the C6H5 radical has been studied by ab initio molecular orbital and statistical-theory calculations. Three low-energy decomposition channels, including the commonly assumed decyclization/fragmentation process yielding n-C4H3 + C2H2, have been identified. With a modified Gaussian-2 method of Mebel et al. (ref 17), the energy barrier for the decyclization of C6H...
متن کامل