MeAPSO-83 Molecular Sieve High Charge Density Synthesis
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Solution Overview
Problem
There is a gap in the development of microporous silicoaluminophosphate materials with intermediate to high charge densities, particularly in the MeAPSO compositions, which have not progressed beyond minor substitution levels of Si and M2+ ions, limiting their thermal stability and adsorption capacity compared to SAPO and MeAPO materials.
Innovation Solution
A new family of metalloalumino(gallo)-phosphosilicate molecular sieves, MeAPSO-83, with a BPH topology is synthesized, featuring higher charge densities through the use of a mixed quaternary ammonium/alkali structure directing agent system, including ethyltrimethylammonium and potassium, which allows for increased incorporation of Si and M2+ ions, forming 'Si islands' and achieving higher framework charge densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If substitution levels of Si and M2+ ions are increased in MeAPSO compositions, then framework charge density and adsorption capacity are improved, but thermal stability deteriorates
Solution Approach 1:
The patent changes the compositional parameters by introducing a mixed SDA system with specific molar ratios of quaternary ammonium to alkali metal (0.1-2.0), and controls the substitution levels within specific ranges (Si: 0.01-2.0, M2+: 0.1-1.0). This parameter optimization resolves the contradiction by finding the optimal balance point where high charge density is achieved while maintaining thermal stability through the stabilizing effect of alkali metals.
Solution Approach 2:
The patent creates a composite framework structure combining multiple T-atoms (Al, Si, P, M2+) with a mixed cation system (quaternary ammonium and alkali metal). This composite approach allows the material to simultaneously achieve high charge density from M2+ substitution and thermal stability from the alkali metal component, resolving the contradiction between these two properties.
2Quantity of substance
If substitution levels of Si and M2+ ions are increased in MeAPSO compositions, then adsorption capacity is improved, but structural stability deteriorates
Solution Approach 1:
The patent optimizes substitution parameters within specific ranges (Si: 0.01-2.0, M2+: 0.1-1.0) and controls the SDA composition ratio (0.1-2.0), achieving high adsorption capacity while maintaining structural stability. The controlled substitution level prevents framework collapse while maximizing active sites for adsorption.
Solution Approach 2:
The mixed SDA system acts as an intermediary that mediates between the framework structure and the substitution level. The alkali metal component specifically stabilizes the framework during high substitution, while the quaternary ammonium directs the crystal structure formation, allowing high adsorption capacity without sacrificing structural integrity.
3Quantity of substance
If mixed quaternary ammonium/alkali structure directing agent system is used, then charge density and adsorption capacity are improved, but device complexity increases
Solution Approach 1:
The patent simplifies the complex mixed SDA system by defining specific, controllable parameter ranges: quaternary ammonium to alkali metal molar ratio (0.1-2.0), Si substitution (0.01-2.0), and M2+ substitution (0.1-1.0). These quantified parameters transform a complex synthesis problem into a manageable optimization task with clear target ranges.
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
MeAPSO-83 exhibits enhanced thermal stability and adsorption capacity, bridging the charge density gap between existing MeAPSOs and higher charge density materials, enabling effective use in hydrocarbon conversion processes and separation applications.
Implementation Method 1
Synthetic zeolites are prepared via hydrothermal synthesis employing suitable sources of Si, Al and structure directing agents (SDAs) such as alkali metals, alkaline earth metals, amines, or organoammonium cations.
Implementation Method 2
Zeolites can be used as catalysts for hydrocarbon conversion reactions, which can take place on outside surfaces of the zeolite as well as on internal surfaces within the pores of the zeolite.
Implementation Method 3
Zeolites are crystalline aluminosilicate compositions which are microporous and which are formed from corner sharing [AlO4/2]− and SiO4/2 tetrahedra.
Data Source
AI summary
A new family of crystalline microporous metalloalumino(gallo)phosphosilicates designated MeAPSO-83 has been synthesized. 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 an 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 are stabilized by combinations of alkali and quaternary ammonium cations, enabling unique, high charge density compositions. The MeAPSO-83 family of materials have the BPH topology and have catalytic properties for carrying out various hydrocarbon conversion processes and separation properties for separating at least one component.