Application of a multi-channel in-situ infrared spectroscopy: The case of LLM-105

Xiao, Qian; Sui, Heliang; Hao, Xiaofei; Chen, Jie; Yin, Ying; Qian, Yu; Yang, Xiulan; Ju, Xin

doi:10.1016/j.saa.2020.118577

Cited by 7 publications

(4 citation statements)

References 32 publications

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“…All three of the first-step reactions, shown in Figure , can independently lead to ring opening and the formation of various intermediates and partial ring species. These compare well to recent FT-IR results, which showed intramolecular H transfer and NO 2 scission as first-step pathways . This overall reaction pathway is similar to that of TATB, which is to be expected, due to its similarity in molecular and crystal structure to LLM-105.…”

Section: Decomposition and Reaction Mechanismssupporting

confidence: 90%

“…Additionally, DFT calculations coupled with thermodynamic theory have allowed for predictions of detonation conditions, as well as initial thermal decomposition pathways predicted from bond dissociation energies . Recent Fourier-transform infrared (FT-IR) work has shown initial reaction pathways of intramolecular H transfer and NO 2 scission reactions . Additionally, in situ IR experiments of gas-releasing reactions showed early products of H 2 O and NH 3 , followed by nitrogen gas products such as NO 2 , NO, and HN, with a final step releasing CO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Predicted Reaction Mechanisms, Product Speciation, Kinetics, and Detonation Properties of the Insensitive Explosive 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

et al. 2021

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Diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a relatively new and promising insensitive high-explosive (IHE) material that remains only partially characterized. IHEs are of interest for a range of applications and from a fundamental science standpoint, as the root causes behind insensitivity are poorly understood. We adopt a multitheory approach based on reactive molecular dynamic simulations performed with density functional theory, density functional tight-binding, and reactive force fields to characterize the reaction pathways, product speciation, reaction kinetics, and detonation performance of LLM-105. We compare and contrast these predictions to 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), a prototypical IHE, and 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (HMX), a more sensitive and higher performance material. The combination of different predictive models allows access to processes operative on progressively longer timescales while providing benchmarks for assessing uncertainties in the predictions. We find that the early reaction pathways of LLM-105 decomposition are extremely similar to TATB; they involve intra-and intermolecular hydrogen transfer. Additionally, the detonation performance of LLM-105 falls between that of TATB and HMX. We find agreement between predictive models for firststep reaction pathways but significant differences in final product formations. Predictions of detonation performance result in a wide range of values, and one-step kinetic parameters show the similar reaction rates at high temperatures for three out of four models considered.

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Section: Decomposition and Reaction Mechanismssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Predicted Reaction Mechanisms, Product Speciation, Kinetics, and Detonation Properties of the Insensitive Explosive 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

et al. 2021

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“…3 Structure of multi-channel in situ reaction system. 25 console desk can transmit instructions to the reaction system, such as temperature, heating rate, single-reaction chamber measurement time and the time for rotating disk to run for one revolution, etc. Each reaction chamber of the reaction system is independently controlled by the console desk.…”

Section: Characterization Methodsmentioning

confidence: 99%

Application of multi-channel in situ infrared spectroscopy: the case of PVB thermal aging

Xu,

Liang,

Jin

et al. 2023

RSC Adv.

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“…另一方面, 含能材料的热分解也是影响其加工和运输过程安全的重要因素之一, 其中LLM-105分子的分解机制可用于阐明其结构的热稳定性 [23] . 由于 LLM-105结构的稳定性, 其热分解过程可能会经历几个步骤来破坏C -N杂环和氢键 [24,25] . 原位红外光谱通过实时监测LLM-105的分子结构证实氢转移和C -NO 2 均裂是控制LLM-105初始反应过程的主要步骤 [26] .…”

Section: Llm-105拉曼振动峰的消失和频移的不连续变化unclassified

Intermolecular interactions and thermodynamic properties of LLM-105

Fan,

Gao,

Wang

et al. 2024

Acta Phys. Sin.

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2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a typical high-energy and low-sensitivity energetic material (EM), which has excellent detonation performance and thermal stability. Based on quasi-harmonic approximation, the dispersion corrected density functional theory was used to study the intermolecular interactions and thermodynamic properties of energetic LLM-105 crystal. By introducing the zero-point energy and temperature effect corrections, PBE-D3 dispersion correction scheme could significantly improve the calculation accuracy of structural parameters at experimental temperature (294 K). The temperature dependent lattice parameters and thermal expansion coefficients exhibit strong anisotropy, especially the thermal expansivity in b-axis orientation (intermolecular layers) is much higher than that in the ac plane (intramolecular layers). Through Hirshfeld surface and fingerprint analysis, it was found that the intermolecular interactions of LLM-105 are mainly O···H hydrogen bonding interactions. The change of intermolecular interactions would result in the rotation of nitro group, which could contribute to form new hydrogen-bonding interaction pattern. Mulliken population analysis shows that the bond order of C−NO2 bond is more sensitive to the change of temperature, which may be the trigger bond for the high-temperature decomposition reaction of LLM-105. The fundamental thermodynamic properties of EMs can not only provide key parameters for mesoscopic or macroscopic thermodynamic simulations, but also gain theoretical insights into the temperature effects of EMs. Specific heat capacity reflects the amount of heat to be supplied to heat the matter and it is important to the risk assessment of EMs during storage or when exposed to external thermal stimuli. Herein, the basic thermodynamic parameters, such as heat capacity, entropy, bulk modulus and elastic constants under different conditions are predicted. Among them, the calculated heat capacity and entropy describe the nonlinear behaviors within the temperature range of 0−500 K, and the calculated isobaric heat capacity Cp(T) is in good agreement with the available experimental measurements. The elasticity of materials describes the macroscopic response of crystals to external forces, and the bulk modulus B0 of molecular crystals can be determined through the equation of state, which is an important parameter for evaluating material stiffness. The bulk modulus under adiabatic conditions is in reasonable agreement with experimental values, and the evolution of bulk modulus with temperature reflects the softening behaviors of LLM-105 at temperature. Furthermore, the complete set of second-order elastic constants (SOECs) of LLM-105 is calculated and 13 independent SOECs (C11, C12, C13, C15, C22, C23, C25, C33, C35, C44, C46, C55, C66) are predicted. With the increasing temperature, all elastic constants gradually decrease due to the weaken of intermolecular interactions of LLM-105. Overall, these results would fundamentally provide a deep understanding of temperature effects and serve as a reference for the experimental measurement of the thermodynamic parameters of EMs.

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Application of a multi-channel in-situ infrared spectroscopy: The case of LLM-105

Cited by 7 publications

References 32 publications

Predicted Reaction Mechanisms, Product Speciation, Kinetics, and Detonation Properties of the Insensitive Explosive 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

Predicted Reaction Mechanisms, Product Speciation, Kinetics, and Detonation Properties of the Insensitive Explosive 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

Application of multi-channel in situ infrared spectroscopy: the case of PVB thermal aging

Intermolecular interactions and thermodynamic properties of LLM-105

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