Boron Nitride Catalyst Vacant Site Defects Hydrogenation
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Solution Overview
Problem
Current catalytic hydrogenation processes rely on rare and costly metals and require elevated temperatures and pressures, limiting their efficiency and sustainability.
Innovation Solution
A hexagonal boron nitride catalyst with frustrated Lewis pairs, created through non-stoichiometric molar ratios of boron and nitrogen, is developed, allowing for hydrogenation at moderate temperatures and pressures without the use of costly metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare metal elements (Pd, Pt, Rh, Ru, In, Ce) are used as hydrogenation catalysts, then catalytic activity is achieved, but cost and availability are worsened due to high cost and limited supply
Solution Approach 1:
The patent replaces expensive rare metal catalysts with a metal-free boron nitride catalyst that uses inexpensive boron and nitrogen sources. The catalyst achieves comparable catalytic activity without relying on costly precious metals, directly addressing the cost and availability problem while maintaining reliability.
Solution Approach 2:
The patent changes the chemical composition parameters by using non-stoichiometric ratios of boron to nitrogen (specifically 1:4 to 1:8 or 4:1 to 8:1) to create vacant site defects in the boron nitride lattice. This parameter change enables the metal-free catalyst to achieve the necessary catalytic activity typically associated with rare metals.
2Productivity
If elevated temperatures (over 200°C or 250°C) and elevated pressure (above 1, 5, or 10 atm) are used for hydrogenation, then reaction rate is improved, but energy consumption and operational complexity are worsened
Solution Approach 1:
The patent changes the operational parameters by enabling hydrogenation reactions to proceed at moderate temperatures (below 200°C) and reduced pressures (1-5 atm) through the introduction of vacant site defects in the boron nitride catalyst. This dramatically reduces energy consumption while maintaining acceptable reaction rates.
Solution Approach 2:
The metal-free boron nitride catalyst with vacant site defects enables milder reaction conditions, replacing the need for expensive energy input required by traditional metal catalysts. The catalyst achieves high productivity under energy-efficient conditions.
3Stability of the object's composition
If stoichiometric boron nitride (1:1 B:N ratio) is used, then lattice stability is maintained, but catalytic activity is worsened due to absence of vacant site defects
Solution Approach 1:
The patent deliberately changes the stoichiometric ratio of boron to nitrogen from the standard 1:1 to non-stoichiometric ratios (1:4 to 1:8 or 4:1 to 8:1). This parameter change creates vacant site defects in the lattice that provide the necessary catalytic activity while the overall hexagonal structure remains stable enough to function as a catalyst.
Solution Approach 2:
The patent introduces local defects (vacant sites) into the boron nitride lattice by using non-stoichiometric composition. These localized imperfections create highly reactive sites with Lewis acid-base pairs that provide catalytic activity, while the bulk lattice maintains its structural stability.
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 boron nitride catalyst demonstrates substantial hydrogenation ability under milder conditions, surpassing state-of-the-art metal-free analogues in catalytic efficiency and operational feasibility.
Implementation Method 1
hexagonal boron nitride in which the ordered lattice structure is punctuated by the presence of highly reactive vacant site defects, also referred to herein as frustrated Lewis pairs (FLPs), unsaturated sites, or unbonded or Lewis B or N sites
Implementation Method 2
The hexagonal boron nitride material described herein is advantageously free of costly metals (i.e., 'metal-free') and can be operated at more moderate temperatures and at a lower pressure, which may even be ambient pressure (about 1 atm)
Implementation Method 3
heating a molten mixture of NaBH4 and NaNH2 under an inert atmosphere to a temperature of at least 700° C.
Implementation Method 4
the hexagonal boron nitride contains boron atoms and nitrogen atoms present in a B:N molar ratio of 1:4-1:8 or 4:1-8:1, wherein the foregoing molar ratios provide vacant site defects within the boron nitride hexagonal lattice structure
Data Source
AI summary
A composition comprising a boron nitride hexagonal lattice structure in which boron atoms and nitrogen atoms are present in a B:N molar ratio of 1:4-1:8 or 4:1-8:1, wherein the molar ratio corresponds to vacant site defects within the boron nitride hexagonal lattice structure. Also described are methods for producing the boron nitride composition as well as methods for using the boron nitride composition as a catalyst in a hydrogenation process.