1
|
Mao JS, Wang BG, Zhu R, Chen YF, Fu JB. Investigation of the decomposition mechanism of MTNP melt-cast explosive at different temperatures and pressures through ReaxFF/lg molecular dynamics simulations. J Mol Model 2023; 29:354. [PMID: 37910219 DOI: 10.1007/s00894-023-05760-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
CONTEXT Thermal decomposition of 1-methyl-3,4,5-trinitropyrazole (MTNP), a melt-cast explosive, was investigated at different temperatures (2500, 2750, 3000, 3250, and 3500 K) and pressures (3000 K/0.5 GPa, 3000 K/1 GPa) using the ReaxFF/lg force field. The study aimed to analyze the changes in reactant quantities, initial reaction pathways, and final product yields. The results demonstrated that complete decomposition of MTNP molecules occurred within a timeframe of 200 ps, with shorter decomposition times observed as the temperature increased. The high-temperature thermal decomposition of MTNP was found to follow two primary reaction pathways. Reaction 1 involved denitration, while reaction 2 proceeded with nitro group isomerization. DFT calculations indicated that nitro group isomerization was the most favorable reaction. During the initial stages, higher quantities of NO2, NO, and N2 were observed compared to other species. This can be attributed to the relatively higher nitrogen and oxygen content in the MTNP structure. Among the five reaction temperatures, it was observed that the quantities of small molecules followed the order of NO2 > NO > N2 > CO. Moreover, with increasing temperature, the quantities of all four small molecules increased, indicating that higher temperatures promoted the progression of the reactions. However, as the pressure increased, there was a trend of initially increasing and then decreasing to zero for the quantities of NO2 and NO. This suggests that high temperature accelerated the high-temperature thermal decomposition of NO2 and NO, leading to a significant increase in the content of N2. METHODS A 3 × 5 × 5 supercell model of MTNP was constructed in Materials Studio, consisting of 75 unit cells and 300 MTNP molecules. The model was then subjected to a 20 ps geometric optimization using the Polak-Ribiere version of the conjugate gradient (CG) algorithm in the large-scale atomic/molecular massively parallel simulator (LAMMPS) under the isothermal-isobaric (NPT) ensemble at 1 atm pressure and 300 K temperature. Following the optimization, molecular dynamics simulations were performed on the model at five temperatures (2500, 2750, 3000, 3200, and 3500 K) under 1 atm using the NPT ensemble for a total duration of 1 ns. During the simulations, atomic trajectories, as well as information on atomic and molecular species, were output every 500 steps. Subsequently, a custom script was utilized to analyze the thermal decomposition pathways and products. A time step of 0.1 fs was employed for the calculations, and periodic boundary conditions were applied to eliminate boundary effects.
Collapse
Affiliation(s)
- Jian-Sen Mao
- School of Environmental and Safety Engineering, North University of China, Taiyuan, 030051, China
| | - Bao-Guo Wang
- School of Environmental and Safety Engineering, North University of China, Taiyuan, 030051, China.
| | - Rui Zhu
- School of Environmental and Safety Engineering, North University of China, Taiyuan, 030051, China
| | - Ya-Fang Chen
- School of Environmental and Safety Engineering, North University of China, Taiyuan, 030051, China
| | - Jian-Bo Fu
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China
| |
Collapse
|
2
|
Bai H, Luo Y, Jiang J, Gou R, Zhang S, Hu W. Molecular dynamics simulation of initial thermal decomposition mechanism of DNTF. J Mol Model 2022; 28:111. [DOI: 10.1007/s00894-022-05095-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 03/15/2022] [Indexed: 10/18/2022]
|
3
|
Song S, Tian X, Wang Y, Qi X, Zhang Q. Theoretical insight into density and stability differences of RDX, HMX and CL-20. CrystEngComm 2022. [DOI: 10.1039/d1ce01577j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this work, density and stability differences of RDX, HMX and CL-20 are exploited and addressed through static calculations from views of monomolecular parameters, intermolecular interactions (by the proposed BEC method) and crystal packing.
Collapse
Affiliation(s)
- Siwei Song
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621000, China
| | - Xiaolan Tian
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621000, China
- School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yi Wang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621000, China
| | - Xiujuan Qi
- School of Material Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Qinghua Zhang
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621000, China
| |
Collapse
|
4
|
Yang Z, Fu-sheng Y, Feng-qi Z, Si-yu X. Interaction Mechanism between Metal Hydrides and Energetic Compounds: an Extensive Literature Survey. FIREPHYSCHEM 2021. [DOI: 10.1016/j.fpc.2021.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
5
|
Wang XK, Zhao Y, Zhao FQ, Xu SY, Ju XH. Atomic perspective revealing for combustion evolution of nitromethane/nano-aluminum hydride composite. J Mol Graph Model 2021; 108:107987. [PMID: 34303180 DOI: 10.1016/j.jmgm.2021.107987] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/27/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022]
Abstract
Adding aluminum hydride (AlH3) into energetic materials (EMs) can improve their combustion and energy performance effectively. However, the potential mechanism of AlH3 on EMs is still unclear. Based on the ReaxFF-lg method, the thermal decomposition of nitromethane/nano-aluminum hydride (NM/nano-AlH3) composites were studied. The addition of AlH3 reduces the energy barrier and increases the energy release during the decomposition of NM, accelerates the decomposition of NM. The main way of AlH3 oxidation involves the capture of O atoms from NM. The results show that AlH3 content and passivated layer affect the oxidation and hydrogen release of AlH3. The explosion of small particle size AlH3 leads to rapid oxidation and hydrogen release. The oxidation of large particle size AlH3 is dominated by the inward and outward diffusion of O and Al atoms. The products of NM/nano-AlH3 composites are H2O, CO2, N2 gases, and Al clusters. This work is expected to guide the application of AlH3 in EMs.
Collapse
Affiliation(s)
- Xin-Ke Wang
- Key Laboratory of Soft Chemistry and Functional Materials of MOE, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Ying Zhao
- Key Laboratory of Soft Chemistry and Functional Materials of MOE, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Feng-Qi Zhao
- Science and Technology on Combustion and Explosion Laboratory, Xi'an Modern Chemistry Research Institute, Xi'an, 710065, PR China
| | - Si-Yu Xu
- Science and Technology on Combustion and Explosion Laboratory, Xi'an Modern Chemistry Research Institute, Xi'an, 710065, PR China
| | - Xue-Hai Ju
- Key Laboratory of Soft Chemistry and Functional Materials of MOE, School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China.
| |
Collapse
|
6
|
Zhao Y, Mei Z, Zhao FQ, Xu SY, Ju XH. Insight into the combustion mechanism of nitroglycerin/nano-aluminum composite materials. Struct Chem 2021. [DOI: 10.1007/s11224-020-01640-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
7
|
Han Q, Zhu W. Effect of particle size on the thermal decomposition of nano ε-CL-20 by ReaxFF-lg molecular dynamics simulations. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.138067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
8
|
Reactive molecular dynamics simulation of thermal decomposition for nitromethane/nano-aluminum composites. J Mol Model 2020; 26:300. [PMID: 33052478 DOI: 10.1007/s00894-020-04562-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 10/07/2020] [Indexed: 10/23/2022]
Abstract
The thermal decomposition of pure nitromethane (NM) and NM/nano-aluminum (Al) composites was simulated by reactive molecular dynamics with ReaxFF-lg corrected force field parameters. The initial decomposition pathway of NM molecules in pure NM is C-N bond rupture. However, NM is decomposed early by the initial pathway of N-O bond rupture when it mixes with nano-Al because of the strong attraction of Al to O. The decomposition process of NM/nano-Al can be divided into three stages: adsorption, slow decomposition, and rapid decomposition. The addition of nano-Al particles decreases the energy barrier in decomposition, increases the released energy, and reduces the decomposition temperature of NM. Adding 3% Al to the explosive can make the detonation pressure 3.083% higher than that of pure system. Compared with pure NM, the energy barrier of 16% Al composite is 25.63 kcal/mol lower and the energy released is 22.99 kcal/mol more. There is an optimal amount of Al contents being added to the NM composite by which the largest total numbers of gaseous products (N2, H2O, and CO2) are released. The effect of Al additives on CO2 production is the most obvious. The maximum detonation pressure can be achieved by adding an appropriate amount of nano-Al, which is similar to the experimental results. Graphical abstract.
Collapse
|
9
|
Zhao Y, Mei Z, Zhao FQ, Xu SY, Ju XH. Thermal Decomposition Mechanism of 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane Accelerated by Nano-Aluminum Hydride (AlH 3): ReaxFF-Lg Molecular Dynamics Simulation. ACS OMEGA 2020; 5:23193-23200. [PMID: 32954170 PMCID: PMC7495736 DOI: 10.1021/acsomega.0c02968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
ReaxFF-low-gradient reactive force field with CHONAl parameters is used to simulate thermal decomposition of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) and AlH3 composite. Perfect AlH3 and surface-passivated AlH3 particles were constructed to mix with HMX. The simulation results indicate HMX is adsorbed on the surface of particles to form O-Al and N-Al bonds. The decomposition of HMX and AlH3 composite is an exothermic reaction without energy barrier, but the decomposition of pure HMX needs to overcome the energy barrier of 133.57 kcal/mol. Active nano-AlH3 causes HMX to decompose rapidly at low temperature, and the primary decomposition pathway is the rupture of N-O and C-N bonds. Adiabatic simulation shows that the energy release and temperature increase of HMX/AlH3 is much larger than those of the HMX system. Surface-passivated AlH3 particles only affect the initial decomposition rate of HMX. In HMX and AlH3 composites, the strong attraction of Al in AlH3 to O and the activation of the intermediate reaction by H2 cause HMX to decompose rapidly. The final decomposition products of pure HMX are H2O, N2, and CO2, and those of HMX/AlH3 are H2O, N2, and Al-containing clusters dominated by C-Al. The final gas production shows that the specific impulse of HMX/AlH3 is larger than that of HMX.
Collapse
Affiliation(s)
- Ying Zhao
- Key
Laboratory of Soft Chemistry and Functional Materials of MOE, School
of Chemical Engineering, Nanjing University
of Science and Technology, Nanjing 210094, P. R. China
| | - Zheng Mei
- Key
Laboratory of Soft Chemistry and Functional Materials of MOE, School
of Chemical Engineering, Nanjing University
of Science and Technology, Nanjing 210094, P. R. China
| | - Feng-Qi Zhao
- Science
and Technology on Combustion and Explosion Laboratory, Xian Modern Chemistry Research Institute, Xian 710065, P. R. China
| | - Si-Yu Xu
- Science
and Technology on Combustion and Explosion Laboratory, Xian Modern Chemistry Research Institute, Xian 710065, P. R. China
| | - Xue-Hai Ju
- Key
Laboratory of Soft Chemistry and Functional Materials of MOE, School
of Chemical Engineering, Nanjing University
of Science and Technology, Nanjing 210094, P. R. China
| |
Collapse
|
10
|
Hu Y, Zhu Z, Shao HZ, Xiao JM, Xu M, Zhao L, Zhuang J. Atomic dynamics of stress-induced lattice misalignment structures in a KDP subsurface. RSC Adv 2020; 10:23944-23952. [PMID: 35517337 PMCID: PMC9055117 DOI: 10.1039/d0ra01291b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/15/2020] [Indexed: 12/30/2022] Open
Abstract
We present an ab initio molecular dynamics study of the thermal stability and dynamics behaviors of lattice misalignment structures (LMSs) in the subsurface layers of KH2PO4 (KDP) crystals. The dehydration process at the atomic scale is observed in the LMS system, which is the same as that in a perfect KDP crystal. However, the paths entering the dehydration process are various. The interesting result is that compared with a perfect KDP crystal, many new paths appear in the LMS system, and even in the same paths, the dehydration is more likely to happen in the LMS system. This leads to a dramatic increase in the dehydration numbers in the LMS system, for which the reasons are given in terms of structural deformation and/or uneven distribution of protons. The results elucidate the underlying atomic mechanism of the effect of LMS defects on the thermal stability of KDP material. Compared with perfect KDP (PS), the dehydration paths and dehydration numbers in the lattice misalignment structures (LMS1, LMS2) increase significantly.![]()
Collapse
Affiliation(s)
- Y Hu
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University Shanghai 200433 China
| | - Z Zhu
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University Shanghai 200433 China
| | - H Z Shao
- College of Electrical and Electronic Engineering, Wenzhou University Wenzhou 325035 China
| | - J M Xiao
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University Shanghai 200433 China
| | - M Xu
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University Shanghai 200433 China
| | - L Zhao
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University Shanghai 200433 China
| | - J Zhuang
- Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University Shanghai 200433 China
| |
Collapse
|
11
|
Jeon WC, Lee JH, Kim JC, Kang SJ, Jung SH, Cho SG, Kwak SK. Reaction kinetics of mixture of nitromethane and detonator confined in carbon nanotube. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2019.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
12
|
Potential Functions and Thermodynamic Properties of UC, UN, and UH. J CHEM-NY 2020. [DOI: 10.1155/2020/7512737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Potential energy surface scanning for UC, UN, and UH was performed by configuration interaction (CI), coupled cluster singles and doubles (CCSD) excitation, quadratic configuration interaction (QCISD (T)), and density functional theory PBE1 (DFT-PBE1) methods in coupling with the ECP80MWB_AVQZ + 2f basis set for uranium and 6 − 311 + G∗for carbon, hydrogen, and nitrogen. The dissociation energies of UC, UN, and UH are 5.7960, 4.5077, and 2.6999 eV at the QCISD (T) levels, respectively. The calculated energy was fitted to the potential functions of Morse, Lennard-Jones, and Rydberg by using the least square method. The anharmonicity constant of UC is 0.0047160. The anharmonic frequency of UC is 780.27 cm−1which was obtained based on the PBE1 results. For UN, the anharmonicity constant is 0.0049827. The anharmonic frequency is 812.65 cm−1which was obtained through the PBE1 results. For UH, the anharmonicity constant is 0.017300. The anharmonic frequency obtained via the QCISD (T) results is 1449.8 cm−1. The heat capacity and entropy in different temperatures were calculated using anharmonic frequencies. These properties are in good accordance with the direct DFT-UPBE1 results (for UC and UN) and QCISD (T) results (for UH). The relationship of entropy with temperature was established.
Collapse
|
13
|
Dong RK, Mei Z, Zhao FQ, Xu SY, Ju XH. Molecular dynamics simulation on the reaction of nano-aluminum with water: size and passivation effects. RSC Adv 2019; 9:41918-41926. [PMID: 35541598 PMCID: PMC9076561 DOI: 10.1039/c9ra08484c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/11/2019] [Indexed: 11/21/2022] Open
Abstract
The reaction of aluminum and water is widely used in the field of propulsion and hydrogen production, but its reaction characteristics at the nanometer scale have not been fully studied. In this paper, the effect of particle size and surface passivation of aluminum particle on the reaction mechanism was studied by using reactive molecular dynamics (RMD) simulation. The reduction of aluminum particle size can accelerate the reaction rate in the medium term (20–80 ps) due to the increase of activity, but it also produces an agglomeration effect as the temperature increases. The presence of surface passivation reduces the proportion of active aluminum and the yield of hydrogen decreases by 30% and 33%, respectively, as the particle size decreases from 2.5 nm to 1.6 nm. The addition of AlH3 can overcome these drawbacks when some aluminum powders are replaced by AlH3. The hydrogen yield is increased by the reaction 2AlH3 + 3H2O → Al2O3 + 6H2. In the reaction of surface passivated Al (1.6 nm in diameter) and H2O, when the proportion of AlH3 reaches 25%, the energy release and hydrogen yield increase from 59.47 kJ mol−1 and 0.0042 mol g−1 to 142.56 kJ mol−1 and 0.0076 mol g−1, respectively. This performance even approximates the reaction of pure aluminum with water: 180.67 kJ mol−1 and 0.0087 mol g−1. In addition, the surface passivation affects the reaction mechanism. Before the passivation layer melts, the reaction 4Al + Al2O3 → 3Al2O occurs inside the nanoparticles. The temperature distribution, number of Al–O bonds and hydrogen yield evolution with time.![]()
Collapse
Affiliation(s)
- Rui-Kang Dong
- School of Chemical Engineering
- Nanjing University of Science and Technology
- Nanjing 210094
- P. R. China
| | - Zheng Mei
- School of Chemical Engineering
- Nanjing University of Science and Technology
- Nanjing 210094
- P. R. China
| | - Feng-Qi Zhao
- Laboratory of Science and Technology on Combustion and Explosion
- Xi'an Modern Chemistry Research Institute
- Xi'an 710065
- P. R. China
| | - Si-Yu Xu
- Laboratory of Science and Technology on Combustion and Explosion
- Xi'an Modern Chemistry Research Institute
- Xi'an 710065
- P. R. China
| | - Xue-Hai Ju
- School of Chemical Engineering
- Nanjing University of Science and Technology
- Nanjing 210094
- P. R. China
| |
Collapse
|
14
|
Mei Z, An Q, Zhao FQ, Xu SY, Ju XH. Reactive molecular dynamics simulation of thermal decomposition for nano-aluminized explosives. Phys Chem Chem Phys 2018; 20:29341-29350. [DOI: 10.1039/c8cp05006f] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The catalytic effect of nano-Al particles on thermal decomposition of RDX, reducing the onset temperature of generating H2O and CO2 (ΔTo < 0).
Collapse
Affiliation(s)
- Zheng Mei
- Key Laboratory of Soft Chemistry and Functional Materials of MOE
- School of Chemical Engineering
- Nanjing University of Science and Technology
- Nanjing 210094
- P. R. China
| | - Qi An
- Department of Chemical and Materials Engineering
- University of Nevada Reno
- Reno
- USA
| | - Feng-Qi Zhao
- Laboratory of Science and Technology on Combustion and Explosion
- Xi’an Modern Chemistry Research Institute
- Xi’an 710065
- P. R. China
| | - Si-Yu Xu
- Laboratory of Science and Technology on Combustion and Explosion
- Xi’an Modern Chemistry Research Institute
- Xi’an 710065
- P. R. China
| | - Xue-Hai Ju
- Key Laboratory of Soft Chemistry and Functional Materials of MOE
- School of Chemical Engineering
- Nanjing University of Science and Technology
- Nanjing 210094
- P. R. China
| |
Collapse
|