AlPO-75 Metallophosphate Sieve Framework Charge Density
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Solution Overview
Problem
There is a lack of high framework charge density MeAPO, SAPO, and MeAPSO compositions with enhanced ion exchange capacity and acid site density, which limits their applications in catalysis and separation processes.
Innovation Solution
The synthesis of a new family of microporous metallophosphate molecular sieves, AlPO-75, with a SAO topology, incorporating higher levels of divalent metals and silicon, which increases framework charge density, allowing for higher ion exchange capacity and acid site density, achieved through a specific hydrothermal synthesis process using quaternary ammonium cations and trivalent elements like aluminum or gallium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional MeAPO, SAPO, and MeAPSO compositions are used, then the basic molecular sieve structure is maintained, but the framework charge density is insufficient, limiting ion exchange capacity and acid site density
Solution Approach 1:
The patent applies parameter changes by systematically varying the composition ratios of divalent metals (Mg, Zn, Co, Mn), trivalent elements (Al, Ga), and silicon in the molecular sieve framework. By adjusting these compositional parameters within specific ranges, the framework charge density is increased while maintaining structural stability, thereby enhancing ion exchange capacity and acid site density for improved catalytic performance
Solution Approach 2:
The patent employs composite materials by combining multiple divalent metals, trivalent elements, and silicon in a unified molecular sieve framework. This composite approach allows synergistic effects where different elements contribute to various properties: divalent metals provide framework charge, trivalent elements maintain structural integrity, and silicon modulates pore characteristics, collectively achieving high framework charge density with enhanced functionality
2Quantity of substance
If higher levels of divalent metals and silicon are incorporated to increase framework charge density, then ion exchange capacity and acid site density are enhanced, but the synthesis process complexity increases
Solution Approach 1:
The patent simplifies the synthesis process by establishing specific compositional parameter ranges and temperature/time conditions. By defining clear guidelines for heteroatom incorporation (e.g., specific ratios of Mg/Al/Zn/Co/Mn to framework atoms) and controlling synthesis parameters (temperature, time, pH), the complex process of incorporating multiple elements is standardized and made more reproducible
Solution Approach 2:
The patent applies preliminary action by pre-forming structure directing agents and preparing reagent mixtures with predetermined compositions before the actual synthesis. The structure directing agents are prepared in advance, and the reaction mixtures are pre-assembled with correct stoichiometry, allowing the hydrothermal synthesis to proceed more efficiently with controlled heteroatom insertion without requiring complex in-process adjustments
3Ease of manufacture
If conventional synthesis methods are used, then the synthesis process is simple, but the framework charge density remains low, limiting catalytic applications
Solution Approach 1:
The patent maintains synthesis simplicity by using a straightforward hydrothermal method with controlled parameter changes. The process involves mixing reagents in specific ratios, adjusting pH to defined ranges, and controlling temperature and time parameters. These controlled parameter changes enable high framework charge density to be achieved through systematic variation of compositional parameters rather than complex procedural steps
Solution Approach 2:
The patent employs structure directing agents as intermediaries that facilitate the incorporation of divalent metals and silicon into the molecular sieve framework during hydrothermal synthesis. These intermediaries mediate between the reagents and the forming framework, guiding the assembly process to achieve high framework charge density while maintaining relatively simple synthesis conditions and procedural steps
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 AlPO-75 material exhibits significantly higher heteroatom insertion, leading to enhanced ion exchange capacity and acid site density, making it suitable for improved catalytic performance and separation processes, including hydrocarbon conversion and contaminant removal.
Implementation Method 1
achieved through a specific hydrothermal synthesis process using quaternary ammonium cations and trivalent elements like aluminum or gallium
Implementation Method 2
having a significant ion exchange capacity
Implementation Method 3
capable of reversibly desorbing an adsorbed phase which is dispersed throughout the internal voids of the crystal
Data Source
AI summary
A new family of a microporous crystalline metallophosphate-based materials designated AlPO-75 has been synthesized. These metallophosphate-based materials are represented by the empirical formulaRp+rMw2+ExPSiyOz where R is a quaternary ammonium cation such as N,N,N′,N′-tetramethyl-N,N′-p-xyleno-1,6-hexanediammonium, M is a divalent framework metal such as magnesium or zinc, E is a framework element such as aluminum or gallium and the framework may optionally contain silicon. The microporous AlPO-75 compositions are characterized by having the SAO topology and have catalytic properties for carrying out various hydrocarbon conversion processes and separating properties for separating at least one component.