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Identification of Thermal Decomposition Products and Reactions for Liquid Ammonium Nitrate on the Basis of Ab Initio Calculation
Author(s) -
Izato YuIchiro,
Koshi Mitsuo,
Miyake Atsumi
Publication year - 2017
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21058
Subject(s) - chemistry , thermal decomposition , ab initio , decomposition , ammonium nitrate , ammonium , ab initio quantum chemistry methods , computational chemistry , inorganic chemistry , molecule , organic chemistry
This work analyzed the thermal decomposition of ammonium nitrate (AN) in the liquid phase, using computations based on quantum mechanics to confirm the identity of the products observed in past experimental studies. During these ab initio calculations, the CBS‐QB3//ωB97XD/6–311++G(d,p) method was employed. It was found that one of the most reasonable reaction pathways is HNO 3 + NH 4 + → NH 3 NO 2 + + H 2 O followed by NH 3 NO 2 + + NO 3 – → NH 2 NO 2 + HNO 3 . In the case in which HNO 3 accumulates in the molten AN, alternate reactions producing NH 2 NO 2 are HNO 3 + HNO 3 → N 2 O 5 + H 2 O and subsequently N 2 O 5 + NH 4 + → NH 2 NO 2 + H 2 O. In both scenarios, HNO 3 plays the role of a catalyst and the overall reaction can be written as NH 4 + + NO 3 – (AN) → NH 2 NO 2 + H 2 O. Although the unimolecular decomposition of NH 2 NO 2 is thermodynamically unfavorable, water and bases both promote the decomposition of this molecule to N 2 O and H 2 O. Thus AN thermal decomposition in the liquid phase can be summarized as NH 4 + + NO 3 – (AN) → N 2 O + 2H 2 O.