Mayenite Cage Incorporates Imide Anions for Stable Storage
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Solution Overview
Problem
Conventional metal imides are highly reactive and decompose rapidly when exposed to the atmosphere or solvents, making them unsuitable for practical use as hydrogen storage materials or catalysts.
Innovation Solution
A mayenite-type compound with a nanoporous cage structure is immersed in liquefied ammonia at specific temperatures and pressures to incorporate imide anions, such as NH2-, which are stable and can be released as ammonia, allowing for their use in chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal imides are used as hydrogen storage materials or catalysts, then they exhibit high reactivity and strong basicity, but they decompose rapidly when exposed to the atmosphere
Solution Approach 1:
The imide anion (NH2-) is nested within the cage structure of the mayenite-type compound. The cage encloses the imide anion, protecting it from external atmosphere while maintaining its reactive properties. This nested structure allows the imide anion to be stable in atmosphere yet retain its functionality for hydrogen storage and catalysis.
Solution Approach 2:
The mayenite-type compound possesses a nanoporous cage structure with specific aperture sizes. These porous cages selectively accommodate imide anions while preventing their decomposition by blocking exposure to atmospheric moisture and oxygen, thus resolving the contradiction between reactivity and stability.
2Manufacturing precision
If the cage size is reduced to accommodate smaller anions, then the selectivity increases, but the imide anion may not fit properly
Solution Approach 1:
The mayenite-type compound exhibits local quality variations in its cage structure, with specific cage apertures sized at approximately 4 Å that are optimally suited for imide anion incorporation. This local structural characteristic provides selective accommodation of imide anions while maintaining their stability, resolving the contradiction between selectivity and proper fit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The imide anions are stably incorporated into the mayenite-type compound, maintaining stability up to 500°C and enabling their use as a stable inorganic imide compound for applications in organic synthesis and catalytic reactions.
Implementation Method 1
a mayenite-type compound immersed in liquefied ammonia in a predetermined temperature range has a property of incorporating an imide anion into the cage
Implementation Method 2
the imide anions are released in the form of ammonia (NH2-→NH3) upon heating treatment
Data Source
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AI summary
The invention related to a material that can stably hold an imide anion (NH2-) therein even in the atmosphere or in a solvent, and a method for synthesizing the material and a use of the material. A mayenite-type compound into which imide anions are incorporated at a concentration of 1 × 1018 cm-3 or more are provided. The mayenite-type compound can be produced by heating a mayenite-type compound including electrons or free oxygen ions in a cage thereof, in liquefied ammonia at 450 to 700°C and at a pressure of 30 to 100 MPa. The compound has properties such that active imide anions can be easily incorporated into the compound and the active imide anions can be easily released in the form of ammonia from the compound, and the compound has chemical stability.