Thermal Interaction Mechanisms of Ammonium Perchlorate and Ammonia Borane

Ammonia borane (AB), with a theoretical hydrogen content of 19.6 wt%, is constrained by its low crystalline density (0.758 g/cm<sup>3</sup>) and poor thermal stability (decomposing at 100 °C). In this study, AB/ammonium perchlorate (AP) composites were synthesized via freeze-drying at a...

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Bibliographic Details
Main Authors: Yunlong Zhang, Rui Pu, Shaoli Chen, Qilong Yan
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/13/2680
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Summary:Ammonia borane (AB), with a theoretical hydrogen content of 19.6 wt%, is constrained by its low crystalline density (0.758 g/cm<sup>3</sup>) and poor thermal stability (decomposing at 100 °C). In this study, AB/ammonium perchlorate (AP) composites were synthesized via freeze-drying at a 1:1 molar ratio. The integration of AP introduced intermolecular interactions that suppressed AB decomposition, increasing the onset temperature by 80 °C. Subsequent vacuum calcination at 100 °C for 2 h formed oxygen/fuel-integrated ammonium perchlorate borane (APB), which achieved decomposition temperatures exceeding 350 °C. The proposed mechanism involved AB decomposing into borazine and BN polymers at 100 °C, which then NH<sub>3</sub>BH<sub>2</sub><sup>+</sup>/ClO<sub>4</sub><sup>−</sup> combined to form APB. At 350 °C, APB underwent the following redox reactions: 4NH<sub>3</sub>BH<sub>2</sub>ClO<sub>4</sub> → N<sub>2</sub>↑ + 4HCl↑ + 2B<sub>2</sub>O<sub>3</sub> + N<sub>2</sub>O↑ + O<sub>2</sub>↑ + 7H<sub>2</sub>O↑ + H<sub>2</sub>↑, while residual AP decomposed. The composite exhibited improved density (1.66 g/cm<sup>3</sup>) and generated H<sub>2</sub>, N<sub>2</sub>, O<sub>2,</sub> and HCl, demonstrating potential for hydrogen storage. Additionally, safety was enhanced by the suppression of AB’s exothermic decomposition (100–200 °C). APB, with its high energy density and thermal stability, was identified as a promising high-energy additive for high-burning-rate propellants.
ISSN:1420-3049