Mechanism development of aqueous hydroxylammonium nitrate under thermal decomposition conditions

Kaiqiang Zhang, Stefan T. Thynell

Research output: Contribution to conferencePaper

Abstract

A detailed chemical mechanism was recently developed for aqueous hydroxylammonium nitrate (HAN), a potential green propellant material, based on theoretical quantum mechanical (QM) calculations. The ωB97X-D density functional theory (DFT) with the SMD solvation model was implemented to optimize the molecular geometries, locate transition states, and compute the solution-phase free energies. The mechanism includes the nitration reactions between hydroxylamine and nitric acid, the subsequent nitrosation reactions between hydroxylamine and HONO, and the autocatalytic steps of H-abstraction by NO2. To examine the mechanism, the kinetic modeling was performed with rate constants predicted by the conventional transition-state theory (CTST) and with consideration to effects from diffusion. The kinetic modeling predicted that the activation energy for 0.1 m HAN is 109 kJ/mol, compared to the experimentally reported 103±21 kJ/mol. NO2, the major H-abstraction agent, only evolves substantially after over 99.9% of the hydroxylamine is consumed. The kinetic simulation also supports that the decomposition can be greatly accelerated with excess nitric acid, but largely suppressed with insufficient acid or excess hydroxylamine.

Original languageEnglish (US)
StatePublished - Jan 1 2018
Event2018 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2018 - State College, United States
Duration: Mar 4 2018Mar 7 2018

Other

Other2018 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2018
CountryUnited States
CityState College
Period3/4/183/7/18

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Physical and Theoretical Chemistry
  • Chemical Engineering(all)

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  • Cite this

    Zhang, K., & Thynell, S. T. (2018). Mechanism development of aqueous hydroxylammonium nitrate under thermal decomposition conditions. Paper presented at 2018 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2018, State College, United States.