Accession Number:

ADA609691

Title:

Ab initio Kinetics of Methylamine Radical Thermal Decomposition and H-abstraction from Monomethylhydrazine by H Atom

Descriptive Note:

Conference paper

Corporate Author:

AIR FORCE RESEARCH LAB EDWARDS AFB CA ROCKET PROPULSION DIV

Report Date:

2014-08-01

Pagination or Media Count:

19.0

Abstract:

Methylamine radicals CH3NH and amino radicals NH2 are the major products in the early ignitionpyrolysis of monomethylhydrazine CH3NHNH2. The kinetics of thermal decomposition of CH3NH radicals was analyzed by RRKM master equation analysis. It was found that Beta scission of the methyl H atom from CH3NH radicals is dominant and fast enough to induce subsequent H-abstraction reactions to trigger ignition. The gas-phase kinetics of H-abstraction reactions from CH3NHNH2 by H atoms was further investigated by ab initio second-order multireference perturbation theory and quadratic-configuration-interaction calculations. The rate coefficients for each of the abstraction channels were quantified by micro-canonical transition state theory, and the associated branching ratios determined. It was found that the total rate coefficient determined from ab initio kinetics theories is in excellent agreement with the experimental value observed at room temperature. Thus the theoretical rate coefficients from this work should be reliable over a wide temperature range and are essential parameters in the development of reaction mechanisms for the kinetics modeling of ignition involving monomethylhydrazine and its derivatives.

Subject Categories:

  • Physical Chemistry
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE