Ab initio Kinetics of Methylamine Radical Thermal Decomposition and H-abstraction from Monomethylhydrazine by H Atom
Abstract
Methylamine radicals (CH3NH) and amino radicals (NH2) are the major products in the early ignition/pyrolysis 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2014
- Accession Number
- ADA609691
Entities
People
- Chung K. Law
- Ghanshyam L Vaghjiani
- Hongyan Sun
Organizations
- Air Force Research Laboratory