High Charge Density MeAPSO Molecular Sieves for Catalysis
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Solution Overview
Problem
There is a gap in the development of microporous silicoaluminophosphate materials with intermediate silicon and phosphorus levels, lacking compositions of intermediate to high charge density, particularly in the MeAPSO family, which are crucial for industrial applications such as catalysis and separation processes.
Innovation Solution
A new family of high charge density metalloalumino(gallo)phosphosilicate molecular sieves (HCD MeAPSO) is synthesized using a mixed quaternary ammonium/alkali structure directing agent system, incorporating more Me2+ and Si4+ ions, achieving higher charge densities and forming 'Si islands' within the framework.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional MeAPSO materials are used with low substitution levels of Me2+ for Al3+, then the framework charge density is low, but the catalytic activity and separation capability are insufficient
Solution Approach 1:
The patent changes the compositional parameters by increasing the substitution level of Me2+ for Al3+ from traditional low levels (around 10%) to high levels (40% or more), thereby increasing the framework charge density and improving catalytic activity and separation capability
Solution Approach 2:
The patent creates composite materials by incorporating multiple cations (Me2+, alkali metals, and quaternary ammonium cations) into the MeAPSO framework, achieving high charge density while maintaining structural stability through the synergistic effect of different cations
2Reliability
If high levels of Me2+ substitution (40% or more) are introduced to increase charge density, then catalytic properties improve, but the structural stability and framework integrity may be compromised
Solution Approach 1:
The patent applies local quality by distributing different cations (Me2+, alkali metals, and quaternary ammonium cations) at different locations within the framework, with Me2+ providing charge density and alkali/ammonium cations providing structural stabilization, thereby maintaining both high catalytic activity and framework stability
Solution Approach 2:
The patent uses alkali metals and quaternary ammonium cations as intermediary species that mediate between the high charge density requirement and framework stability, balancing the electrostatic forces and preventing framework collapse while allowing high Me2+ substitution
3Adaptability or versatility
If intermediate silicon and phosphorus levels are incorporated to create high charge density materials, then new catalytic applications become possible, but the synthesis complexity and difficulty increase
Solution Approach 1:
The patent achieves universality by developing a multi-functional synthesis system that simultaneously incorporates Me2+, Si4+, and P5+ ions while using a combination of structure-directing agents to guide the formation of the desired framework, thereby simplifying the synthesis process despite the complexity of incorporating multiple elements
Solution Approach 2:
The patent applies preliminary action by pre-mixing the cationic components (Me2+, alkali metals, and quaternary ammonium cations) with the framework precursors before hydrothermal treatment, allowing the structure-directing agents to organize the components into the desired framework structure during crystallization, thereby reducing synthesis complexity
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 HCD MeAPSO materials exhibit enhanced catalytic properties and separation capabilities due to their high charge density and microporosity, bridging the charge density gap in existing MeAPSO materials and enabling more efficient hydrocarbon conversion and separation processes.
Implementation Method 1
These species balance the framework charge associated with aluminum
Implementation Method 2
Zeolites are microporous and which are formed from corner sharing [AlO4/2]− and SiO4/2 tetrahedra
Data Source
AI summary
A method of making and using a new family of crystalline microporous metalloalumino(gallo)phosphosilicate molecular sieves is disclosed. These molecular sieves have been synthesized and are designated high charge density (HCD) MeAPSOs. These metalloalumino(gallo)phosphosilicates are represented by the empirical formula of:Rp+rA+mM2+wExPSiyOz where A is an alkali metal such as potassium, R is at least one quaternary ammonium cation such as ethyltrimethylammonium, M is a divalent metal such as Zn and E is a trivalent framework element such as aluminum or gallium. This family of metalloalumino(gallo)phosphosilicate materials is stabilized by combinations of alkali and quaternary ammonium cations, enabling unique, high charge density compositions. The HCD MeAPSO family of materials have catalytic properties for carrying out various hydrocarbon conversion processes and separation properties for separating at least one component.