Amine Boranes. I. Kinetics of Acid Hydrolysis of Trimethylamine Borane

Ryschkewitsch, G. E.

doi:10.1021/ja01498a014

Cited by 55 publications

(26 citation statements)

References 2 publications

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“…In an acid solution, TMAB is decomposed by hydrolysis 26) . Because of this decomposition, we are concerned that a uniform bulk sample cannot be obtained from electrodeposition with TMAB.…”

Section: Resultsmentioning

confidence: 99%

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Fabricating Bulk Nanocrystalline Ni–W–B Alloys by Electrodeposition

Matsui

Omura

2017

Mater. Trans.

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In this study, we fabricated bulk nanocrystalline Ni-W-B alloys by electrodeposition, using trimethylamine-borane (TMAB) as a boron source, showing how B doping affects tensile properties. In electrodeposition, the TMAB concentration was varied from 0 to 5.0 g/L. Adding TMAB to the deposition bath increased the B content of the electrodeposited alloys up to 0.36 at%, but did not signi cantly change the W content or grain size. Adding more TMAB than 0.1 g/L drastically decreased the material s tensile elongation. Cross-sectional hardness tests on alloys with poor ductility revealed non-uniform hardness and that the initial layer had a high hardness of 6.3-8.7 GPa. This result indicated that the TMAB had immediately decomposed and that the boron decomposition product was mixed into the initial electrodeposited layer. In contrast, the alloys electrodeposited with 0.01-0.05 g/L TMAB showed good tensile elongation of 11%. Our results reveal the appropriate amount of added TMAB in order to produce electrodeposited bulk samples with good ductility.

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“…In an acid solution, TMAB is decomposed by hydrolysis 26) . Because of this decomposition, we are concerned that a uniform bulk sample cannot be obtained from electrodeposition with TMAB.…”

Section: Resultsmentioning

confidence: 99%

“…These results indicate that hydrolyss of TMAB immediately occurred during electrodeposition. In addition, the hydrolysis of TMAB in the acid solution generated hydrogen gas 26) . Repeatedly trapping and desorption of hydrogen gas introduces high internal stress and defects 7,27,28) .…”

Section: Resultsmentioning

confidence: 99%

Fabricating Bulk Nanocrystalline Ni–W–B Alloys by Electrodeposition

Matsui

Omura

2017

Mater. Trans.

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“…Several kinetic studies reported on amine boranes demonstrated that these borane complexes are much more resistant to hydrolysis in acidic media than [BH 4 ] -. In general, the second-order rate constants for acid hydrolysis are several orders of magnitude smaller than that of [BH 4 ] -and are dramatically dependent on the number and nature of alkyl groups bound to nitrogen; for example, for BH 3 (NH 3 ), BH 3 (tert-ButylNH 2 ), BH 3 (Me 2 NH), and BH 3 (NMe 3 ) they are 6.0, 0.87, 9.7 × 10 -3 and 1.2 × 10 -4 L mol -1 s -1 , respectively [62,68,80] (see Table 3 for pH conditions and other amine boranes). For alkylamine boranes, BH 3 (NR 3 ) (R = alkyl, H), the most likely mechanism for acid hydrolysis differs from both those proposed for [BH 4 ] -, and it is the attack of protic species on nitrogen, followed by the displacement of BH 3 :…”

Section: Hydrolysis Of Amine Boranesmentioning

confidence: 99%

“…The BH 3 (H 2 O) is hydrolyzed following the same stepwise reaction schemes proposed for [BH 4 ] - [62,68,80], as discussed in Section 2.3. In this reaction scheme, the rate-determining step is represented by the displacement of the amino group.…”

Section: Hydrolysis Of Amine Boranesmentioning

confidence: 99%

Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

D’Ulivo

Dědina

Mester

et al. 2011

Pure and Applied Chemistry

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Aqueous-phase chemical generation of volatile hydrides (CHG) by derivatization with borane complexes is one of the most powerful and widely employed methods for determination and speciation analysis of trace and ultratrace elements (viz. Ge, Sn, Pb, As, Sb, Bi, Se, Te, Hg, Cd, and, more recently, several transition and noble metals) when coupled with atomic and mass spectrometric detection techniques. Analytical CHG is still dominated by erroneous concepts, which have been disseminated and consolidated within the analytical scientific community over the course of many years. The overall approach to CHG has thus remained completely empirical, which hinders possibilities for further development. This report is focused on the rationalization and clarification of fundamental aspects related to CHG: (i) mechanism of hydrolysis of borane complexes; (ii) mechanism of hydrogen transfer from the borane complex to the analytical substrate; (iii) mechanisms through which the different chemical reaction conditions control the CHG process; and (iv) mechanism of action of chemical additives and foreign species. Enhanced comprehension of these different mechanisms and their mutual influence can be achieved in light of the present state of knowledge. This provides the tools to explain the reactivity of a CHG system and contributes to the clarification of several controversial aspects and the elimination of erroneous concepts in CHG.

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“…This value is obtained neglecting that significantly more water will be needed in order to keep the reactants and products in solution and to keep the viscosity of the solution low. In a subsequent step, the remaining BH 3 is hydrolyzed to boric acid [113][114][115]. A comparison of the pH value and the 11 [112].…”

Section: Hydrolysis Of Abmentioning

confidence: 99%

Ammonia Borane and Related Compounds as Hydrogen Source Materials

Mertens

Wolf

Baitalow

2010

Handbook of Hydrogen Storage

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Mainly driven by the efforts of the automotive industry, a strong push towards new concepts to store hydrogen has occurred over recent years. Generally, in this framework, high hydrogen content materials have been of great interest for chemical storage concepts.From weight considerations, the most natural choice to develop hydrogen storage and source materials would be the use of first row element hydrides. Since a high valency allows more hydrogen to bond per atom, the mid-first row hydrides borane, methane, and ammonia with 21, 25, and 17.5 wt% are amongst the materials with the highest hydrogen contents. Although the thermodynamics is not favorable, due to the strong bond between carbon and hydrogen, the utilization of methane as a hydrogen source material has been widely investigated and small natural gas reformers for a fueling station to supply polymer electrolyte membrane (PEM) fuel cell vehicles with hydrogen have been developed [1].However, ammonia and boranes alone are also not very attractive as hydrogen source compounds because of thermodynamic considerations and the harm they potentially bring to fuel cell catalysts (PEM). The interesting fact that nitrogen and boron are on opposite sides of the electronegative-electropositive border line that runs through the periodic table, offers attractive new features to the ammonia borane adduct BH 3 NH 3 (AB). Especially, their ability to release hydrogen at low temperatures, combined with the very high hydrogen content, has brought these materials into the focus of recent research efforts.Besides the fact that the known world boron resources are insufficient to permanently fuel a significant portion of the world vehicle fleet, it is very clear from the energy expense needed for AB regeneration and the cost aspects that ammonia borane-based materials are not likely to become a means of mass hydrogen storage. These materials, however, can be of interest for small scale applications demanding very high hydrogen storage density, such as autonomously operated small electrical Handbook of Hydrogen Storage. Edited by Michael Hirscher j215 devices. Research efforts to put AB materials to use primarily encompass the control of the hydrogen release kinetics, the production of AB materials and the rehydrogenation of the spent materials.Since spent ammonia borane, or borazane as it is also called, and most of its derivatives are not easily rechargeable, for thermodynamic reasons, new recycling strategies need to be developed. An essential part of possible recycling schemes is the generation of hydridic, that is, negatively charged, hydrogen located at the boron centers. Because of the importance of borohydrides in organic synthesis and the recent developments in nonmetal-center-based hydrogen activation [2], the relevance of these research efforts is outside the area of hydrogen source and storage materials. Materials Description and Characterization

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Amine Boranes. I. Kinetics of Acid Hydrolysis of Trimethylamine Borane

Cited by 55 publications

References 2 publications

Fabricating Bulk Nanocrystalline Ni–W–B Alloys by Electrodeposition

Fabricating Bulk Nanocrystalline Ni–W–B Alloys by Electrodeposition

Mechanisms of chemical generation of volatile hydrides for trace element determination (IUPAC Technical Report)

Ammonia Borane and Related Compounds as Hydrogen Source Materials

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