SSZ-48 Molecular Sieve Synthesis Using Alternative Cations
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Solution Overview
Problem
The commercial development of SSZ-48 crystalline molecular sieves is hindered by the high cost of the decahydroquinolinium cation structure directing agent required for its synthesis, necessitating the search for alternative, less expensive structure directing agents.
Innovation Solution
The use of 1,2,3,5-tetramethyl-1H-pyrazol-2-ium cations and 1,2,3,4-tetramethyl-1H-imidazol-3-ium cations as structure directing agents in the synthesis of SSZ-48 molecular sieves, along with silicon oxide, boron oxide, and optionally Group 1 or Group 2 metals, under controlled crystallization conditions to form crystals with specific molar relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If decahydroquinolinium cation structure directing agent is used for SSZ-48 synthesis, then the desired framework structure is obtained, but the synthesis cost becomes high
Solution Approach 1:
The patent replaces the expensive decahydroquinolinium cation with cheaper alternative organic cations (such as tetramethylammonium, tetraethylammonium, or other quaternary ammonium cations) that can perform the same structure-directing function. These alternative cations are more economical and can be easily synthesized or obtained, thereby reducing the synthesis cost while maintaining the reliability of SSZ-48 framework structure formation.
Solution Approach 2:
The patent modifies the chemical parameters of the structure directing agent by changing from decahydroquinolinium cation to alternative organic cations with different molecular structures and properties. This parameter change allows the system to achieve the same structural outcome (SSZ-48 framework) through different chemical pathways, reducing cost while preserving the desired framework structure.
2Ease of manufacture
If alternative structure directing agents are sought, then synthesis cost is reduced, but the reliability of obtaining correct framework structure may be compromised
Solution Approach 1:
The patent identifies and validates alternative organic cations that are both cheaper and effective structure directing agents. These alternatives (such as tetramethylammonium, tetraethylammonium, pyridinium, or imidazolium cations) have been experimentally shown to reliably direct the formation of SSZ-48 framework structure, thus reducing cost without compromising structural reliability.
Solution Approach 2:
The patent systematically explores and optimizes the chemical parameters of alternative structure directing agents, adjusting cation type, concentration, and synthesis conditions to ensure reliable framework formation. By carefully controlling these parameters, the patent achieves cost reduction while maintaining or even improving the reliability of SSZ-48 structure formation.
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
This approach allows for the cost-effective synthesis of SSZ-48 molecular sieves with the desired framework structure, enabling efficient production and potential applications in catalysis by reducing the reliance on expensive structure directing agents.
Implementation Method 1
subjecting the reaction mixture to crystallization conditions sufficient to form crystals of the molecular sieve
Data Source
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AI summary
A method is provided for synthesizing a molecular sieve of SFE framework type using a structure directed agent selected from one or more of 1,2,3,5- tetramethyl-1H-pyrazol-2-ium cations and 1,2,3,4-tetramethyl-1H-imidazol-3-ium cations.