Sublimation and thermal decomposition of ammonia borane: Competitive processes controlled by pressure

Kondrat'ev, Yu. V.; Butlak, Alina V.; Kazakov, I. V.; Timoshkin, Alexey Y.

doi:10.1016/j.tca.2015.08.021

Cited by 20 publications

(13 citation statements)

References 51 publications

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“…Brutto heat effects of the processes, which compounds 1 and 3 undergo under vacuum (residual pressure circa 0.09 Torr) at 358 K (for 1 and 3) and 434 K (for 1), were measured by a drop-calorimetry method. [32] It was found that 1 undergoes very slow (circa 57 h) endothermic process at 358 K and reduced (ca. 0.09 Torr) pressure, followed by slow exothermic thermal decomposition.…”

Section: Calorimetry Studymentioning

confidence: 99%

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile

Shcherbina

Pomogaeva

Lisovenko

et al. 2020

Zeitschrift anorg allge chemie

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Complexes formed by interaction of E(C6F5)3 (E = B, Al, Ga, In) with excess of acetonitrile (AN) were structurally characterized. Quantum chemical computations indicate that for Al(C6F5)3 and In(C6F5)3 the formation of a complex of 1:2 composition is more advantageous than for B(C6F5)3 and Ga(C6F5)3, in line with experimental observations. Formation of the solvate [Al(C6F5)3·2AN]·AN is in agreement with predicted thermodynamic instability of [Al(C6F5)3·3AN]. Tensimetry study of B(C6F5)3·CH3CN reveals its stability in the solid state up to 197 °C. With the temperature increase, the complex undergoes irreversible thermal decomposition with pentafluorobenzene formation.

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Section: Calorimetry Studymentioning

confidence: 99%

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile

Shcherbina

Pomogaeva

Lisovenko

et al. 2020

Zeitschrift anorg allge chemie

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“…It indicates that the direct dehydrogenation from B groups to form H atoms is the primary pathway for the initial decomposition, which is never observed in the conditions just with heating or pressuring. 25,29 After that, some NH 2 BH 3 are generated, followed by the rapid formation of H 2 molecules. Apparently, the early dehydrogenation through the breakage of the B−H bond is more favorable than that of the N−H bond, but the later one is also contributed to H 2 release.…”

Section: Evolutions Of Electronmentioning

confidence: 99%

“…Cooperating with temperature, pressure always plays another key role in the chemical reaction. 29 Liang et al 30 proposed that when the system is heated at 6 GPa, the initial reaction follows an intermolecular pathway. Three AB molecules release two H 2 through concerted interaction.…”

Section: Introductionmentioning

confidence: 99%

Dehydrogenation and Rehydrogenation of Ammonia Borane under Shock Loading: Ab Initio Molecular Dynamics Simulations

Huang

Shi

et al. 2020

J. Phys. Chem. C

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Ammonia borane (AB, NH3BH3), as a hydrogen-rich material, has been attracting great interest in the field of hydrogen storage. However, the mechanism of its dehydrogenation and rehydrogenation is not sufficiently understood yet. In this work, the initial decomposition process of AB under shock loading is investigated using the ab initio molecular dynamics method. The results show that the B–H bond breaking plays a more important role in the reaction initiation. Three main reaction pathways for H2 release are revealed. (I) Heteropolar dihydrogen interaction (N-Hδ+···δ−H–B) and (II) homopolar dihydrogen interaction (B–Hδ−···δ−H–B) are still the most popular reaction mechanisms. However, a direct hydrogen adsorption and H2 liberation mechanism (III) is uncovered. The H radical readily adsorbs a B atom to form the pentacoordinate boron-containing species and efficiently activates the adjacent B–H bond, which further ruptures to form H2 molecules. What is more, we discover the unexpected hydrogenation behaviors between new-formed H2 and BNH compounds. In addition, the similar H exchange reactions assisted by H2 are also explored. The probable rehydrogenation mechanisms are proposed based on our results. These theoretical calculations not only give a comprehensive understanding about AB decomposition under shock loading but also shed light on its rehydrogenation for hydrogen storage.

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“…The brutto-effects of the processes occurring with E(C 6 F 5 ) 3 •Et 2 O (E = B, Al, Ga, In) at 85°C in a vacuum (residual pressure ≈ 0.1 Torr) were determined by a drop-calorimetric method with DAC1-1a differential automatic calorimeter. [64] E(C 6 F 5 ) 3 •Et 2 O (E = Al, Ga, In) were synthesized by reactions of a Grignard reagent C 6 F 5 MgBr with the respective metal trichloride according to the literature procedure. [9] Caution: to lower risk of explosion a rigorous stirring is strongly recommended when refluxing in toluene.…”

Section: Methodsmentioning

confidence: 99%

“…The brutto‐effects of the processes occurring with E(C 6 F 5 ) 3 · Et 2 O (E = B, Al, Ga, In) at 85 °C in a vacuum (residual pressure ≈ 0.1 Torr) were determined by a drop‐calorimetric method with DAC1‐1a differential automatic calorimeter. [ 64 ]…”

Section: Methodsmentioning

confidence: 99%

Structural and Energetic Features of Group 13 Element Trispentafluorophenyl Complexes with Diethyl Ether

et al. 2020

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The complexes of group 13 element trispentafluorophenyl derivatives E(C6F5)3 (E = B, Al, Ga, In) with diethyl ether of 1:1 composition have been synthesized and structurally characterized. All compounds are isostructural. Thermal stability studies reveal that at elevated temperatures all complexes decompose with pentafluorobenzene evolution. The geometries and thermodynamic characteristics for the dissociation reactions of the compounds have been computed using three DFT methods. The 1H NMR α‐proton chemical shifts for the coordinated ether in deuteriobenzene and in CD2Cl2 solutions correlate with gas phase dissociation enthalpies of the complexes. Potentially high Lewis acidity of B(C6F5)3 is hindered by the large pyramidalization energy of the acceptor moiety.

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Sublimation and thermal decomposition of ammonia borane: Competitive processes controlled by pressure

Cited by 20 publications

References 51 publications

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile

Dehydrogenation and Rehydrogenation of Ammonia Borane under Shock Loading: Ab Initio Molecular Dynamics Simulations

Structural and Energetic Features of Group 13 Element Trispentafluorophenyl Complexes with Diethyl Ether

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Sublimation and thermal decomposition of ammonia borane: Competitive processes controlled by pressure

Cited by 20 publications

References 51 publications

Structures and Stability of Complexes of E(C6F5)3 (E = B, Al, Ga, In) with Acetonitrile

Structures and Stability of Complexes of E(C6F5)3 (E = B, Al, Ga, In) with Acetonitrile

Dehydrogenation and Rehydrogenation of Ammonia Borane under Shock Loading: Ab Initio Molecular Dynamics Simulations

Structural and Energetic Features of Group 13 Element Trispentafluorophenyl Complexes with Diethyl Ether

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Product

Resources

About

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile

Structures and Stability of Complexes of E(C₆F₅)₃ (E = B, Al, Ga, In) with Acetonitrile