Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2025.02.001
Jun-qing Yang , Zhi-wei Guo , Xiao-he Wang , Ga-zi Hao , Yu-bing Hu , Xiao-jun Feng , Rui Guo , Wei Jiang
This study investigated the impacts of different vacancy defect concentrations on the decomposition of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) under shock wave loading using the ab initio molecular dynamics (AIMD) method combined with the multiscale shock technique (MSST). Initially, eight crystal models of TKX-50 with vacancy defect concentrations of 0 %, 3.13 %, 6.25 %, and 9.38 % were established. The most stable models at these defect concentrations were identified as V0, V1.1, V2.1, and V3.1, respectively by calculating the vacancy formation energies. Afterward, the decomposition processes of these most stable models under shock waves at a speed of 10 km s−1 were examined in detail. The results show that TKX-50 underwent reversible proton transfer processes under shock wave loading, which are similar to its behavior under thermal loading. With an increase in the vacancy defect concentration, the TKX-50 systems became significantly more unstable and compressible, a greater variety and quantity of small gas molecules were quickly generated, and more pronounced fluctuations in the cluster quantities and molecular weight of the largest clusters were observed. These findings demonstrate that vacancy defects can accelerate the decomposition of TKX-50, providing theoretical insights into the damage evolution of TKX-50 under shock wave loading.
采用从头算分子动力学（AIMD）方法结合多尺度激波技术（MSST）研究了不同空位缺陷浓度对激波载荷下二羟铵5,5′-双甾唑-1,1′-二酸盐（TKX-50）分解的影响。首先，建立了空位缺陷浓度分别为0%、3.13%、6.25%和9.38%的TKX-50晶体模型。通过计算空位形成能，确定了缺陷浓度下最稳定的模型分别为V0、V1.1、V2.1和V3.1。随后，详细研究了这些最稳定模式在10 km s−1速度下的分解过程。结果表明，TKX-50在激波载荷下经历了与热载荷相似的可逆质子转移过程。随着空位缺陷浓度的增加，TKX-50体系的不稳定性和可压缩性显著增强，气体小分子的种类和数量迅速增加，最大团簇的团簇数量和分子量波动更为明显。研究结果表明，空位缺陷能够加速TKX-50的分解，为TKX-50在激波载荷作用下的损伤演化提供了理论依据。
{"title":"A theoretical study on the decomposition of TKX-50 with different vacancy defect concentrations under shock wave loading","authors":"Jun-qing Yang , Zhi-wei Guo , Xiao-he Wang , Ga-zi Hao , Yu-bing Hu , Xiao-jun Feng , Rui Guo , Wei Jiang","doi":"10.1016/j.enmf.2025.02.001","DOIUrl":"10.1016/j.enmf.2025.02.001","url":null,"abstract":"<div><div>This study investigated the impacts of different vacancy defect concentrations on the decomposition of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) under shock wave loading using the <em>ab</em> initio molecular dynamics (AIMD) method combined with the multiscale shock technique (MSST). Initially, eight crystal models of TKX-50 with vacancy defect concentrations of 0 %, 3.13 %, 6.25 %, and 9.38 % were established. The most stable models at these defect concentrations were identified as V0, V1.1, V2.1, and V3.1, respectively by calculating the vacancy formation energies. Afterward, the decomposition processes of these most stable models under shock waves at a speed of 10 km s<sup>−1</sup> were examined in detail. The results show that TKX-50 underwent reversible proton transfer processes under shock wave loading, which are similar to its behavior under thermal loading. With an increase in the vacancy defect concentration, the TKX-50 systems became significantly more unstable and compressible, a greater variety and quantity of small gas molecules were quickly generated, and more pronounced fluctuations in the cluster quantities and molecular weight of the largest clusters were observed. These findings demonstrate that vacancy defects can accelerate the decomposition of TKX-50, providing theoretical insights into the damage evolution of TKX-50 under shock wave loading.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 24-34"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2024.08.002
Zi-han Wang , Wei Liu , Yu Dai , Zhong-ping Liu , Meng-dan Ma , Sheng Cui , Xuan He , Yu Liu
In light of escalating global tensions and the persistent frequency of terrorist incidents, explosives have caused unpredictable serious environmental problems in the worldwide. The imperative for rapid, highly sensitive and accurate detection of explosives has been propelled to the forefront of priorities across various fields, especially national defense and environmental protection. Surface-enhanced Raman scattering (SERS) has emerged as a potent technology for the detection of explosives, attributed to its exceptional sensitivity, rapidity and non-destructive characterization of specific analytes. Concurrently, high-performance substrates and portable devices have expanded the use of SERS technology from the lab to field applications, increasing its potential utility. This progress report summarizes the progress of SERS and related integrated technologies for explosives detection in recent years. Following an introductory synopsis of SERS enhancement principles, this exposition focuses on the pivotal role of SERS substrates in the detection of explosives. It delineates the multifaceted advantages of SERS technology in the realm of explosive detection from three critical dimensions: ultra-sensitivity, semi-quantitative and high selectivity. The report subsequently introduces cutting-edge integration techniques that are compatible with SERS, such as portable Raman instruments, on-site wipeable sampling technology and microfluidic devices, all of which are major advances in promoting on-site high-throughput explosives detection programs. In conclusion, this report synthesizes the outcomes attained and delineates prospective directions for future research in the field of SERS explosives detection.
{"title":"On-site trace detection of explosives: From ultra-sensitive SERS to integrated detection technology","authors":"Zi-han Wang , Wei Liu , Yu Dai , Zhong-ping Liu , Meng-dan Ma , Sheng Cui , Xuan He , Yu Liu","doi":"10.1016/j.enmf.2024.08.002","DOIUrl":"10.1016/j.enmf.2024.08.002","url":null,"abstract":"<div><div>In light of escalating global tensions and the persistent frequency of terrorist incidents, explosives have caused unpredictable serious environmental problems in the worldwide. The imperative for rapid, highly sensitive and accurate detection of explosives has been propelled to the forefront of priorities across various fields, especially national defense and environmental protection. Surface-enhanced Raman scattering (SERS) has emerged as a potent technology for the detection of explosives, attributed to its exceptional sensitivity, rapidity and non-destructive characterization of specific analytes. Concurrently, high-performance substrates and portable devices have expanded the use of SERS technology from the lab to field applications, increasing its potential utility. This progress report summarizes the progress of SERS and related integrated technologies for explosives detection in recent years. Following an introductory synopsis of SERS enhancement principles, this exposition focuses on the pivotal role of SERS substrates in the detection of explosives. It delineates the multifaceted advantages of SERS technology in the realm of explosive detection from three critical dimensions: ultra-sensitivity, semi-quantitative and high selectivity. The report subsequently introduces cutting-edge integration techniques that are compatible with SERS, such as portable Raman instruments, on-site wipeable sampling technology and microfluidic devices, all of which are major advances in promoting on-site high-throughput explosives detection programs. In conclusion, this report synthesizes the outcomes attained and delineates prospective directions for future research in the field of SERS explosives detection.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 118-128"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2024.11.003
Yao-yao Linghu , Chao-yang Zhang
It is nowadays challenging to create low sensitivity and high energy molecules (LSHEMs), largely restricted by the high complexity and difficult interpretation of composition-structure-property relationships of energetic materials. In the present theoretical modeling work on energetic materials, we propose a strategy for constructing LSHEMs based on energetic azole isomerism to reduce the molecular complexity while maintain composition. That is, we firstly find that the vicinal combination of N—NH2 and C—NO2 is an effective unit to enhance both energy and molecular stability of azoles. The advantage of the combination largely stems from the oxygen balance improvement to be close to zero to elevate reaction heat and packing density, and the intramolecular hydrogen bond formation to enhance molecular stability. Thus, this unit can be widely considered in constructing N-rich low sensitivity and high energy azole molecules. In addition, we confirm that the N—NO2 generally seriously do harm to the molecular stability of azoles, especially in the case of the existence of steric effect around it.
如今，创造低灵敏度高能量分子（LSHEMs）是一项挑战，这主要受限于高能量材料的高复杂性和难以解释的成分-结构-性质关系。在目前的高能材料理论建模工作中，我们提出了一种基于高能唑异构的 LSHEMs 构建策略，以在保持组成的同时降低分子的复杂性。也就是说，我们首先发现 N-NH2 和 C-NO2 的邻接组合是提高唑类化合物能量和分子稳定性的有效单元。这种组合的优势主要源于氧平衡的改善，使其接近于零，从而提高反应热和堆积密度，同时分子内氢键的形成也提高了分子稳定性。因此，在构建富含 N 的低灵敏度和高能量唑分子时，可以广泛考虑使用该单元。此外，我们还证实，N-NO2 一般会严重损害唑类化合物的分子稳定性，尤其是在其周围存在立体效应的情况下。
{"title":"Vicinal combination of N—NH2 and C—NO2 benefitting for low sensitivity and high energy azole molecules: A strategy developed from isomerization","authors":"Yao-yao Linghu , Chao-yang Zhang","doi":"10.1016/j.enmf.2024.11.003","DOIUrl":"10.1016/j.enmf.2024.11.003","url":null,"abstract":"<div><div>It is nowadays challenging to create low sensitivity and high energy molecules (LSHEMs), largely restricted by the high complexity and difficult interpretation of composition-structure-property relationships of energetic materials. In the present theoretical modeling work on energetic materials, we propose a strategy for constructing LSHEMs based on energetic azole isomerism to reduce the molecular complexity while maintain composition. That is, we firstly find that the vicinal combination of N<strong>—</strong>NH<sub>2</sub> and C<strong>—</strong>NO<sub>2</sub> is an effective unit to enhance both energy and molecular stability of azoles. The advantage of the combination largely stems from the oxygen balance improvement to be close to zero to elevate reaction heat and packing density, and the intramolecular hydrogen bond formation to enhance molecular stability. Thus, this unit can be widely considered in constructing N-rich low sensitivity and high energy azole molecules. In addition, we confirm that the N<strong>—</strong>NO<sub>2</sub> generally seriously do harm to the molecular stability of azoles, especially in the case of the existence of steric effect around it.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 14-23"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2025.02.004
Alexandr V. Stankevich , Svetlana G. Tolshchina , Anna V. Korotina , Rashida I. Ishmetova , Konstantin D. Kozhurkin , Pavel A. Slepukhin , Gennady L. Rusinov , Valery N. Charushin
This work describes the synthesis of molecular and molecular-ionic derivatives of azolo[1,2,4,5]tetrazines and 1,2,4,5-tetrazines containing amino and guanidino fragments. Experimental and computational studies on the contribution of various substituents (guanidine, nitroamine, 2,4,6-trinitroaniline, nitrate ions) into thermal stabilities of compounds, their activation energies and the mechanism of response to external thermal effects were carried out. The thermal stabilities of the compounds were evaluated by using the differential scanning calorimetry. In addition, their energetic characteristics were calculated. The kinetic parameters for the key step of thermal decomposition were calculated. High thermal stability values for compounds with amino groups and low stabilities for nitrates and N-nitro derivatives have been shown. The activation energy values in the series of compounds under consideration proved to be varied from 358 to 112 kJ mol−1, the reaction order from 3 to 6. The catalytic effects of the decomposition of the basic structural fragment for the introduced substituents were found to be from 23 to 232kJ mol−1.
{"title":"Catalytic effects of substituents in amino and guanidino derivatives of azolo-annelated and 3,6-disubstituted 1,2,4,5-tetrazines","authors":"Alexandr V. Stankevich , Svetlana G. Tolshchina , Anna V. Korotina , Rashida I. Ishmetova , Konstantin D. Kozhurkin , Pavel A. Slepukhin , Gennady L. Rusinov , Valery N. Charushin","doi":"10.1016/j.enmf.2025.02.004","DOIUrl":"10.1016/j.enmf.2025.02.004","url":null,"abstract":"<div><div>This work describes the synthesis of molecular and molecular-ionic derivatives of azolo[1,2,4,5]tetrazines and 1,2,4,5-tetrazines containing amino and guanidino fragments. Experimental and computational studies on the contribution of various substituents (guanidine, nitroamine, 2,4,6-trinitroaniline, nitrate ions) into thermal stabilities of compounds, their activation energies and the mechanism of response to external thermal effects were carried out. The thermal stabilities of the compounds were evaluated by using the differential scanning calorimetry. In addition, their energetic characteristics were calculated. The kinetic parameters for the key step of thermal decomposition were calculated. High thermal stability values for compounds with amino groups and low stabilities for nitrates and N-nitro derivatives have been shown. The activation energy values in the series of compounds under consideration proved to be varied from 358 to 112 kJ mol<sup>−1</sup>, the reaction order from 3 to 6. The catalytic effects of the decomposition of the basic structural fragment for the introduced substituents were found to be from 23 to 232kJ mol<sup>−1</sup>.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 74-83"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2025.03.002
Xin-yuan Zhao , Xun Zhang , Hao-tian Yu , Yan Liu , Si-ping Pang , Chun-lin He
Pyrrole is one of the important versatile skeletons for functional materials, fully-substituted pyrroles can achieve multiple substitutions. But, spatial site resistance effects make its synthesis difficult. In this work, a series of fully-iodinated bridged pyrroles (compounds 8–13) as energetic biocidal compounds were synthesized through two-step. They show high iodine content of 82.98 %–88.02 %, and high thermal stability (Td: 267–344 °C) which is a significantly improved compared to 2,3,4,5-tetraiodo-1H-pyrrole (TIPL, Td: 168 °C). Furthermore, good detonation pressure (P) and detonation velocity (D) were realized, showing great prospective for applications as potential energetic biocidal materials.
{"title":"Fully-iodinated bridged pyrroles as high thermostable energetic biocidal materials","authors":"Xin-yuan Zhao , Xun Zhang , Hao-tian Yu , Yan Liu , Si-ping Pang , Chun-lin He","doi":"10.1016/j.enmf.2025.03.002","DOIUrl":"10.1016/j.enmf.2025.03.002","url":null,"abstract":"<div><div>Pyrrole is one of the important versatile skeletons for functional materials, fully-substituted pyrroles can achieve multiple substitutions. But, spatial site resistance effects make its synthesis difficult. In this work, a series of fully-iodinated bridged pyrroles (compounds <strong>8</strong>–<strong>13</strong>) as energetic biocidal compounds were synthesized through two-step. They show high iodine content of 82.98 %–88.02 %, and high thermal stability (<em>T</em><sub>d</sub>: 267–344 °C) which is a significantly improved compared to 2,3,4,5-tetraiodo-1H-pyrrole (TIPL, <em>T</em><sub>d</sub>: 168 °C). Furthermore, good detonation pressure (<em>P</em>) and detonation velocity (<em>D</em>) were realized, showing great prospective for applications as potential energetic biocidal materials.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 67-73"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01DOI: 10.1016/j.enmf.2024.11.006
Jin-xiu Hu , Min-hua Ai , Xian-long Liu , Xiao-lei Guo , Cheng-xiang Shi , Kang Xue , Xiang-wen Zhang , Li Wang , Ji-Jun Zou , Lun Pan
Developing bio-fuels provides a sustainable strategy to reduce the dependence on finite fossil fuels. But biomass-based fuel molecules usually lack strained structure, resulting in undesirable density and impulse for aerospace applications. Herein, the highly strained bio-fuels are synthesized from myrcene by photoinduced [2 + 2] cycloaddition and hydrogenation/cyclopropanation reactions. The triplet energy transfer mechanism is revealed through theoretical calculations, triplet quenching experiments and phosphorescent measurement. The reaction conditions of photocycloaddition reaction are optimized, including the photosensitizer type and amount, solvent effect, substrate concentration, reaction temperature and light intensity. Under the optimal conditions, the yield of target photocycloaddition product reaches ca. 82.61 %, which is then hydrogenated and cyclopropanized to two kinds of bio-fuels, namely PC@HG and PC@CP, respectively, which have high density of 0.836 and 0.886 g mL−1, high impulse of 326.71 and 329.42 s, superior cryogenic properties, and good combustion properties. This work provides a feasible pathway for the preparation of highly strained bio-fuels with high density and high impulse.
开发生物燃料为减少对有限的化石燃料的依赖提供了一种可持续的战略。但生物质燃料分子通常缺乏应变结构，导致不理想的密度和冲量用于航空航天应用。本文以月桂烯为原料，通过光诱导[2 + 2]环加成和加氢/环丙烷反应合成了高应变生物燃料。通过理论计算、三重态猝灭实验和磷光测量揭示了三重态能量传递机理。优化了光环加成反应的反应条件，包括光敏剂种类和用量、溶剂效应、底物浓度、反应温度和光强。在最优条件下，目标光环加成产物产率可达82.61%左右，经加氢和环丙化制得密度分别为0.836和0.886 g mL−1、冲量分别为326.71和329.42 s、低温性能优异、燃烧性能良好的PC@HG和PC@CP两种生物燃料。本研究为高密度、高冲量高应变生物燃料的制备提供了一条可行的途径。
{"title":"[2+2] and [2+1] cycloaddition of myrcene for synthesis of highly strained bio-fuels with high density and high impulse","authors":"Jin-xiu Hu , Min-hua Ai , Xian-long Liu , Xiao-lei Guo , Cheng-xiang Shi , Kang Xue , Xiang-wen Zhang , Li Wang , Ji-Jun Zou , Lun Pan","doi":"10.1016/j.enmf.2024.11.006","DOIUrl":"10.1016/j.enmf.2024.11.006","url":null,"abstract":"<div><div>Developing bio-fuels provides a sustainable strategy to reduce the dependence on finite fossil fuels. But biomass-based fuel molecules usually lack strained structure, resulting in undesirable density and impulse for aerospace applications. Herein, the highly strained bio-fuels are synthesized from myrcene by photoinduced [2 + 2] cycloaddition and hydrogenation/cyclopropanation reactions. The triplet energy transfer mechanism is revealed through theoretical calculations, triplet quenching experiments and phosphorescent measurement. The reaction conditions of photocycloaddition reaction are optimized, including the photosensitizer type and amount, solvent effect, substrate concentration, reaction temperature and light intensity. Under the optimal conditions, the yield of target photocycloaddition product reaches <em>ca.</em> 82.61 %, which is then hydrogenated and cyclopropanized to two kinds of bio-fuels, namely PC@HG and PC@CP, respectively, which have high density of 0.836 and 0.886 g mL<sup>−1</sup>, high impulse of 326.71 and 329.42 s, superior cryogenic properties, and good combustion properties. This work provides a feasible pathway for the preparation of highly strained bio-fuels with high density and high impulse.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"6 1","pages":"Pages 84-94"},"PeriodicalIF":3.3,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.enmf.2023.09.004
Zhi-xiang Zhang , Yi-lin Cao , Chao Chen , Lin-yuan Wen , Yi-ding Ma , Bo-zhou Wang , Ying-zhe Liu
In this study, machine learning (ML)-assisted regression modeling was conducted to predict the thermal decomposition temperatures and explore the factors that correlate with the thermal stability of energetic materials (EMs). The modeling was performed based on a dataset consisting of 885 various compounds using linear and nonlinear algorithms. The tree-based models established demonstrated acceptable predictive abilities, yielding a low mean absolute error (MAE) of 31°C. By analyzing the dataset through hierarchical classification, this study insightfully identified the factors affecting EMs’ thermal decomposition temperatures, with the overall accuracy improved through targeted modeling. The SHapley Additive exPlanations (SHAP) analysis indicated that descriptors such as BCUT2D, PEOE_VSA, MolLog_P, and TPSA played a significant role, demonstrating that the thermal decomposition process is influenced by multiple factors relating to the composition, electron distribution, chemical bond properties, and substituent type of molecules. Additionally, descriptors such as Carbon_contents and Oxygen_Balance proposed for characterizing EMs showed strong linear correlations with thermal decomposition temperatures. The trends of their SHAP values indicated that the most suitable ranges of Carbon_contents and Oxygen_Balance were 0.2∼0.35 and −65∼−55, respectively. Overall, the study shows the potential of ML models for decomposition temperature prediction of EMs and provides insights into the characteristics of molecular descriptors.
{"title":"Machine learning-assisted quantitative prediction of thermal decomposition temperatures of energetic materials and their thermal stability analysis","authors":"Zhi-xiang Zhang , Yi-lin Cao , Chao Chen , Lin-yuan Wen , Yi-ding Ma , Bo-zhou Wang , Ying-zhe Liu","doi":"10.1016/j.enmf.2023.09.004","DOIUrl":"10.1016/j.enmf.2023.09.004","url":null,"abstract":"<div><div>In this study, machine learning (ML)-assisted regression modeling was conducted to predict the thermal decomposition temperatures and explore the factors that correlate with the thermal stability of energetic materials (EMs). The modeling was performed based on a dataset consisting of 885 various compounds using linear and nonlinear algorithms. The tree-based models established demonstrated acceptable predictive abilities, yielding a low mean absolute error (<em>MAE</em>) of 31°C. By analyzing the dataset through hierarchical classification, this study insightfully identified the factors affecting EMs’ thermal decomposition temperatures, with the overall accuracy improved through targeted modeling. The SHapley Additive exPlanations (SHAP) analysis indicated that descriptors such as BCUT2D, PEOE_VSA, MolLog_P, and TPSA played a significant role, demonstrating that the thermal decomposition process is influenced by multiple factors relating to the composition, electron distribution, chemical bond properties, and substituent type of molecules. Additionally, descriptors such as Carbon_contents and Oxygen_Balance proposed for characterizing EMs showed strong linear correlations with thermal decomposition temperatures. The trends of their SHAP values indicated that the most suitable ranges of Carbon_contents and Oxygen_Balance were 0.2∼0.35 and −65∼−55, respectively. Overall, the study shows the potential of ML models for decomposition temperature prediction of EMs and provides insights into the characteristics of molecular descriptors.</div></div>","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"5 4","pages":"Pages 274-282"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135348903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.enmf.2024.01.002
Luciana Amorim da Silva, Gabriel Monteiro-de-Castro, Erick Braga Ferrão Galante, Itamar Borges Jr, Aline Cardoso Anastácio
<div><div>The main challenge in designing new energetic materials is to find a good balance between four seemingly incompatible requirements, namely, high-energy content, low sensitivity, low production costs and less-polluting content. Fused nitrogen heterocycles of imidazole and pyrimidine, such as acyclovir and guanine, may offer interesting features due to the combination of a coplanar framework and a large conjugate system, which contribute to a reduced sensitivity, and a number of energetic bonds that can be increased by the introduction of explosophore substituents. In this work, to evaluate the potential of acyclovir and guanine derivatives as energetic materials, density functional theory (DFT) calculations were carried out to investigate the influence of the type and position of the explosophore substituent groups –<span><math><mrow><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><mi>N</mi><mi>H</mi><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><msub><mi>N</mi><mn>3</mn></msub></mrow></math></span>, –<span><math><mrow><mi>O</mi><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><mi>C</mi><mi>N</mi></mrow></math></span>, <span><math><mrow><mo>−</mo><mi>N</mi><mo>=</mo><mi>N</mi><mo>−</mo><mtext>,</mtext></mrow></math></span> and <span><math><mrow><mo>−</mo><mi>N</mi><mo>=</mo><mi>N</mi><mrow><mo>(</mo><mi>O</mi><mo>)</mo></mrow><mo>−</mo></mrow></math></span> on the energetic properties and chemical reactivity of 91 acyclovir- and guanine-based molecules, including thirty one nitramines, three nitroheterocycles, seventeen azides, seventeen nitrate esters, seventeen nitriles, three azo and three azoxy compounds. Several molecular properties were computed, including the chemical reactivity, the heat of formation and the detonation velocities and pressures using semiempirical equations. Among the molecules with no bridge groups, we found that, except for cyano group, position 4 were the most stable for acyclovir derivatives, whereas, except for the azido group, position 2 and 5 provided the most stable compounds for guanine derivatives. Among the bridged derivatives, depending on the molecule and positions, the nitrate esters and the nitro derivatives were more stable. In comparison with the parent compounds, calculations showed that the heat of formation (HOF) increased the most with azido and cyano groups, the density increased substantially with nitrate esters, nitro and nitramino groups, and the detonation velocities and pressures increased the most with nitrate ester, nitro and nitramino groups. Although azo groups resulted in higher HOFs than azoxy groups, azoxy derivatives showed superior values in terms of density, heat of maximum detonation, detonation velocity and pressure. Four nitrate esters (GD134, GD245, AZOXYGD13 and AZOXYGD25) displayed higher values of detonation velocity and pressure than RDX. The designed nitramin
{"title":"A density functional theory investigation of the substituent effect on acyclovir and guanine derivatives for applications on energetic materials","authors":"Luciana Amorim da Silva, Gabriel Monteiro-de-Castro, Erick Braga Ferrão Galante, Itamar Borges Jr, Aline Cardoso Anastácio","doi":"10.1016/j.enmf.2024.01.002","DOIUrl":"10.1016/j.enmf.2024.01.002","url":null,"abstract":"<div><div>The main challenge in designing new energetic materials is to find a good balance between four seemingly incompatible requirements, namely, high-energy content, low sensitivity, low production costs and less-polluting content. Fused nitrogen heterocycles of imidazole and pyrimidine, such as acyclovir and guanine, may offer interesting features due to the combination of a coplanar framework and a large conjugate system, which contribute to a reduced sensitivity, and a number of energetic bonds that can be increased by the introduction of explosophore substituents. In this work, to evaluate the potential of acyclovir and guanine derivatives as energetic materials, density functional theory (DFT) calculations were carried out to investigate the influence of the type and position of the explosophore substituent groups –<span><math><mrow><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><mi>N</mi><mi>H</mi><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><msub><mi>N</mi><mn>3</mn></msub></mrow></math></span>, –<span><math><mrow><mi>O</mi><mi>N</mi><msub><mi>O</mi><mn>2</mn></msub></mrow></math></span>, –<span><math><mrow><mi>C</mi><mi>N</mi></mrow></math></span>, <span><math><mrow><mo>−</mo><mi>N</mi><mo>=</mo><mi>N</mi><mo>−</mo><mtext>,</mtext></mrow></math></span> and <span><math><mrow><mo>−</mo><mi>N</mi><mo>=</mo><mi>N</mi><mrow><mo>(</mo><mi>O</mi><mo>)</mo></mrow><mo>−</mo></mrow></math></span> on the energetic properties and chemical reactivity of 91 acyclovir- and guanine-based molecules, including thirty one nitramines, three nitroheterocycles, seventeen azides, seventeen nitrate esters, seventeen nitriles, three azo and three azoxy compounds. Several molecular properties were computed, including the chemical reactivity, the heat of formation and the detonation velocities and pressures using semiempirical equations. Among the molecules with no bridge groups, we found that, except for cyano group, position 4 were the most stable for acyclovir derivatives, whereas, except for the azido group, position 2 and 5 provided the most stable compounds for guanine derivatives. Among the bridged derivatives, depending on the molecule and positions, the nitrate esters and the nitro derivatives were more stable. In comparison with the parent compounds, calculations showed that the heat of formation (HOF) increased the most with azido and cyano groups, the density increased substantially with nitrate esters, nitro and nitramino groups, and the detonation velocities and pressures increased the most with nitrate ester, nitro and nitramino groups. Although azo groups resulted in higher HOFs than azoxy groups, azoxy derivatives showed superior values in terms of density, heat of maximum detonation, detonation velocity and pressure. Four nitrate esters (GD134, GD245, AZOXYGD13 and AZOXYGD25) displayed higher values of detonation velocity and pressure than RDX. The designed nitramin","PeriodicalId":34595,"journal":{"name":"Energetic Materials Frontiers","volume":"5 4","pages":"Pages 293-308"},"PeriodicalIF":3.3,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139952275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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