Theoretical study of the decomposition mechanisms and kinetics of the ingredients RDX in composition B

• Published in: Journal of molecular modeling 2012-08, Vol.18 (8), p.3915-3926
• Main Authors: Zhang, Jian-Guo, Wang, Kun, Niu, Xiao-Qing, Zhang, Shao-Wen, Feng, Xiao-Jun, Zhang, Tong-Lai, Zhou, Zun-Ning
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Computer Appl. in Life Sciences; Computer Applications in Chemistry; Computer Simulation; Explosive Agents - chemistry; Kinetics; Models, Chemical; Models, Molecular; Molecular Medicine; Nitrosamines - chemistry; Original Paper; Quantum Theory; Theoretical and Computational Chemistry; Thermodynamics; Trinitrotoluene - chemistry
• ISSN: 1610-2940; 0948-5023
• DOI: 10.1007/s00894-012-1396-1

RDX as a component in composition B (TNT + RDX) was first studied by us on its mechanism and kinetics of decomposition reactions in this paper. We have pointed out three possible pathways and found a new low-energy process of its decomposition. The N—N bond cleavage in composition B has higher dissociation energies than the monomer, but it is also the initial step. The optimized structures and the frequencies of all the stationary points were calculated at the B3LYP/6-31G(d) level. The minimum-energy paths were obtained by using the intrinsic reaction coordinate (IRC) theory, and the reaction potential energy curve was corrected with zero-point energy. Finally, the rate constants were calculated in a wide temperature region from 200 to 2500 K using TST, TST/Eckart theories. The obtained results also indicate that the tunneling effects are remarkable at low temperature (200 K