Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents

Organic Process Research & Development, Journal Year: 2019, Volume and Issue: 24(1), P. 67 - 84

Published: Nov. 28, 2019

Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided industry owing to concerns over instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides other transfer reagents is relatively well understood, but there little reliable data available for compounds. This work first collates sensitivity thermal analysis act an accessible reference resource. Thermogravimetric (TGA), differential scanning calorimetry (DSC), accelerating rate (ARC) the model donor/acceptor compound ethyl (phenyl)diazoacetate presented. We also present a rigorous DSC dataset with 43 compounds, enabling direct comparison energetic materials provide clear academic industrial chemistry communities. Interestingly, range onset temperatures (Tonset) this series which varied between 75 160 °C. variation depends on electronic effect substituents amount charge delocalization. A statistical demonstrated predict differently substituted phenyl diazoacetates. maximum recommended process temperature (TD24) avoid decomposition estimated selected average enthalpy (ΔHD) without functional groups −102 kJ mol–1. Several analyzed using same protocol found have higher stability, general agreement reported values. For azide reagents, ΔHD −201 mol–1 observed. High-quality from ARC experiments shows initiation be 60 °C, compared that 100 °C common reagent p-acetamidobenzenesulfonyl (p-ABSA). Yoshida correlation applied each indication both impact (IS) explosivity. As neat substance, none tested predicted explosive, many (particularly compounds) impact-sensitive. It therefore manipulation, agitation, processing conducted due care impacts, particularly large quantities. full presented inform chemists nature magnitude hazards when reagents. Given rapid heat generation gas evolution, adequate control cautious addition begin reaction strongly conducting reactions

Language: Английский

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Crystal Engineering for Creating Low Sensitivity and Highly Energetic Materials

Crystal Growth & Design, Journal Year: 2018, Volume and Issue: 18(10), P. 5713 - 5726

Published: Sept. 6, 2018

Energy and safety are the two most important concerns of energetic materials (EMs), while they usually contradict each other: high energy typically goes together with low safety. Low sensitivity highly (LSHEMs) balance well thus desired for extensive applications. Nevertheless, on whole, energy–safety contradiction, component limits, insufficient knowledge about relationships among components, structures, properties performances EMs have made development LSHEMs, or even entire group EMs, evolve slowly. This Perspective focuses upon current progress in clarifications contradiction crystal packing–impact relationship EMs. Also, we propose strategies creating new LSHEMs desensitized through engineering, covering traditional composed neutral single-component molecules, cocrystals, ionic salts. Two levels intrinsic molecule crystal, accounted constructing LSHEMs: at molecular level, it is proposed to store much chemical bonds avoiding any bond formation an that too weak intrinsically safety; level suggested intermolecular interactions be enhanced increase packing compactness density strengthen anisotropy facilitate ready shear slide mechanical sensitivity; overall, a big π-bonded oxygen close zero hydrogen bond-aided face-to-face π–π stacking preferred as LSHEM. Hopefully, this will set root establishing systematic theory LSHEMs.

Language: Английский

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Hydrogen Bonding in CHON-Containing Energetic Crystals: A Review

Crystal Growth & Design, Journal Year: 2019, Volume and Issue: 19(10), P. 5981 - 5997

Published: Sept. 9, 2019

Hydrogen bonding (HB) universally exists in CHON-containing energetic materials (EMs) and significantly influences their structures, properties, performances. As time proceeds, some new types of EMs such as cocrystals (ECCs) ionic salts (EISs) are thriving currently richening insight into the HB EMs, these reviewed this article well. The intramolecular mostly stable molecules while seldom less molecules; weak abundant HBs dominate intermolecular interactions consolidate crystal packing. For ECCs with neutral heterogeneous molecules, serve one strategies for design. In comparison, EISs greatly strengthened polarity increases ionization. A strong usually enhances molecular stability large π-bonds packing coefficients facilitates reversible H transfer, which is advantageous low mechanical sensitivity. HB-aided π–π stacking that favors sensitivity observed all three kinds including traditional homogeneous EISs. However, a an EM causes ready thereby worsening thermal stability. Thus, influence on can go both ways, there should be balance when HB-containing designed.

Language: Английский

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Molecular and Crystal Features of Thermostable Energetic Materials: Guidelines for Architecture of “Bridged” Compounds

ACS Central Science, Journal Year: 2019, Volume and Issue: 6(1), P. 54 - 75

Published: Dec. 27, 2019

Extensive density functional theory (DFT) calculation and data analysis on molecular crystal level features of 60 reported energetic materials (EMs) allowed us to define key descriptors that are characteristics these compounds' thermostability. We see as reminiscent "Lipinski's rule 5", which revolutionized the design new orally active pharmaceutical molecules. The proposed for thermostable EMs a type design, location weakest bond in molecule, well specific ranges oxygen balance, packing coefficient, Hirshfeld surface hydrogen bonding, lattice energy. On this basis, we designed three containing bridged, 3,5-dinitropyrazole moieties, HL3, HL7, HL9, were synthesized, characterized, evaluated small-scale field detonation experiments. best overall performing compound HL7 exhibited an onset decomposition temperature 341 °C has 1.865 g cm–3, calculated velocity maximum pressure 8517 m s–1 30.6 GPa, respectively. Considering HL7's impressive safety parameters [impact sensitivity (IS) = 22 J; friction (FS) 352; electrostatic discharge (ESD) 1.05 J] results experiments, guidelines should further promote rational novel EMs, suitable deep drilling, space exploration, other high-value defense civil applications.

Language: Английский

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Review of the molecular and crystal correlations on sensitivities of energetic materials

Journal of Hazardous Materials, Journal Year: 2020, Volume and Issue: 398, P. 122910 - 122910

Published: May 14, 2020

Language: Английский

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π–π Stacking Contributing to the Low or Reduced Impact Sensitivity of Energetic Materials

Crystal Growth & Design, Journal Year: 2020, Volume and Issue: 20(5), P. 2824 - 2841

Published: April 15, 2020

π–π stacking, usually together with the aid of hydrogen bonding (HB), serves as a main characteristic low impact, sensitive, highly energetic materials (LSHEMs), which are desired for application, and attracts considerable attention in designing synthesizing new EMs. This Perspective highlights progress insights into stacking EMs, covering traditional crystals homogeneous neutral molecules, cocrystals (ECCs), ionic salts (EISs). A rather large π-bond is requisite can be classified four patterns, including face-to-face wavelike crossing mixing an increasing difficulty shear sliding, HB plays important role supporting sliding layers. Straightforwardly, pattern–impact sensitivity relationship rooted steric hindrance when preferred to design LSHEMs at crystal level, due least or lowest barrier among patterns. has been extensively observed ECCs, EISs, enlightening us make rule EMs such stacking. However, it still difficult rule, attributed unclear between molecular structures. Maybe, will become increasingly feasible achieve by establishing database detailed information on molecules related amount data collecting experimental predicted results, combining advanced machine learning technologies. Combining this article recent review (Cryst. Growth Des. 2019, 19 (10), 5981–5997), overall perspective intermolecular interactions C, H, O, N atoms could have presented.

Language: Английский

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Assembly of Tetrazolylfuroxan Organic Salts: Multipurpose Green Energetic Materials with High Enthalpies of Formation and Excellent Detonation Performance

Chemistry - A European Journal, Journal Year: 2019, Volume and Issue: 25(16), P. 4225 - 4233

Published: Jan. 15, 2019

A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen-rich cations were synthesized by simple, efficient, scalable chemical routes. These materials fully characterized IR multinuclear NMR (1 H, 13 C, 14 N, 15 N) spectroscopy, elemental analysis, differential scanning calorimetry (DSC). Additionally, the structure an salt consisting azidotetrazolylfuroxan anion 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolium cation was confirmed single-crystal X-ray diffraction. The compounds exhibit good experimental densities (1.57-1.71 g cm-3 ), very high enthalpies formation (818-1363 kJ mol-1 and, as result, excellent detonation performance (detonation velocities 7.54-8.26 kms-1 pressures 23.4-29.3 GPa). Most have moderate sensitivity toward impact friction, which makes them promising candidates for variety applications. At same time, three on primary explosives level (1.5-2.7 J). results along with parameters nitrogen contents (66.0-70.2 %) indicate that these may serve potential environmentally friendly alternatives to lead-based explosives.

Language: Английский

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Alleviating the energy & safety contradiction to construct new low sensitivity and highly energetic materials through crystal engineering

CrystEngComm, Journal Year: 2018, Volume and Issue: 20(13), P. 1757 - 1768

Published: Jan. 1, 2018

Alleviating the energy & safety contradiction of energetic materials through crystal engineering.

Language: Английский

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Hunting for advanced high-energy-density materials with well-balanced energy and safety through an energetic host–guest inclusion strategy

Journal of Materials Chemistry A, Journal Year: 2019, Volume and Issue: 7(33), P. 19248 - 19257

Published: Jan. 1, 2019

A versatile host–guest driven explosive-oxidant inclusion strategy was proposed to develop advanced high-energy-density materials (HEDMs) with high detonation performances, low mechanical sensitivities and excellent combustion properties.

Language: Английский

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Hirshfeld Surface Method and Its Application in Energetic Crystals

Crystal Growth & Design, Journal Year: 2021, Volume and Issue: 21(12), P. 6619 - 6634

Published: Nov. 9, 2021

Understanding intermolecular interactions is fundamental to understanding the molecular stacking structures and some properties of energetic crystals, such as density, energy, mechanics, sensitivity. The Hirshfeld surface method a straightforward tool reveal nowadays has become increasingly popular in field materials. This article highlights wide range applications this describing including hydrogen bonding, π-stacking, halogen lone pair−π (n−π) stacking, patterns, predicting shear sliding characteristic further impact Meanwhile, roughness quantitative description interaction strength method, main shortcoming, pointed out herein. Thus, work expected guide right full use method. Besides, we present perspective about using rapidly screen mode sensitivity; thus, fast screening two most important can be implemented, combination with existing mature energy prediction methods based on components. Thereby, more reliable procedure an additional consideration pattern will produced, setting basis for data-driven crystal engineering research

Language: Английский

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