Computer Modeling of Probable Decomposition Reactions: Cyclonitramines

Abstract

SummaryAn approach to computer synthesis and retrosynthesis of organic compounds was formulated, and the CASB (Computer-Assisted Structure Building) software for its computer implementation was created. The approach was evaluated by the example of computer generation of probable routes for reactions of homolytic decomposition. Elementary steps of homolysis reactions were modeled with the use of the``retrosynthetic'' method. Each elementary reaction describes fragments that should be present in the structure and structural modi®cations that should be carried out to obtain reaction products. Target fragments are described in terms of production rules by specifying types of atoms, their formal charges and radical states, numbers of adjacent heteroatoms, hybridizations, etc. All possible intermediates of molecular homolysis reactions are generated by the program in a single step and then used in further search for probable pathways of decomposition during subsequent steps until the given maximum number of steps is achieved. Screening of advantageous pathways for these reactions was based on a set of empirical rules. The results obtained by the suggested approach and the corresponding program were illustrated by the example of some cyclic nitramines (RDX and HMX) and demonstrated good agreement with the experiment.

Theoretical investigation into the solvent effect on the thermal decomposition of RDX in tetrahydrofuran, acetone, toluene, and benzene

“…By ab initio and density functional theory (DFT) methods, Habibollahzadeh et al [11] found that a competitive reaction occurred between the symmetrical ring-opening reaction and N-NO 2 bond dissociation, with the formation of three methylene nitramines, which was consistent with the experimental result by Liu et al [3]. Wu et al [12] calculated the bond dissociation energy (BDE) of the N-NO 2 bond and the ring-opening energy of the symmetric ring-breaking by DFT, and concluded that the dissociation pathway of the N-NO 2 bond was the main pathway of the decomposition reaction, which was consistent with the semi-empirical PM3 calculation by Pivina et al [13]. Chakraborty et al [14] studied the N-NO 2 bond dissociation, HONO elimination and symmetrical ring-opening by using the B3LYP/6-31G (d) method, and found that the BDE of the N-NO 2 bond and activation energy of the HONO elimination reaction were 39.0 and 39.2 kcal/mol respectively.…”

Chemistry of Organic Nitrates: Thermal Oxidative and Catalytic Chemistry of Organic Nitrates

“…Organic nitrates generate a secondary product (IR absorbance at 1632 cm −1 ) in air that is not produced in a nitrogen atmosphere. The secondary products were identified as α,β-unsaturated carbonyl compounds, which can arise from olefins , or carbonyls , generated in the thermolysis of organic nitrates , (Figure ).…”