Aluminosilicate Zeolite SSZ-33 Synthesis via Organic Dication
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Solution Overview
Problem
Current methods have been unsuccessful in directly synthesizing aluminosilicate zeolite SSZ-33, which is crucial for catalytic reactions due to the limitations of borosilicate SSZ-33's catalytic activity in hydrocarbon conversion processes.
Innovation Solution
A method involving the use of 1,1′-(pentane-1,5-diyl)bis(3-methylcyclohexyl)piperidinium dication as a structure directing agent, along with silicon, aluminum, hydroxide ions, and elements from Groups 1 and 2 of the Periodic Table, under crystallization conditions to form aluminosilicate SSZ-33 crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If borosilicate SSZ-33 is synthesized and used for catalytic reactions, then the molecular sieve structure is formed, but the catalytic activity is insufficient for hydrocarbon conversion processes
Solution Approach 1:
The patent changes the chemical composition parameter by replacing boron with aluminum in the zeolite framework, transforming the material from borosilicate to aluminosilicate SSZ-33. This parameter change fundamentally alters the catalytic properties, providing strong framework acid sites necessary for effective hydrocarbon conversion processes.
2Ease of manufacture
If direct synthesis method is used to prepare aluminosilicate SSZ-33, then the synthesis process is simplified, but previous attempts have been unsuccessful
Solution Approach 1:
The patent uses a specific organic structure-directing agent, 1,1′-(pentane-1,5-diyl)bis(3-methylcyclohexyl)piperidinium dication, as an intermediary to guide the formation of aluminosilicate SSZ-33 during direct synthesis. This SDA mediates the crystallization process, enabling successful direct synthesis by controlling the assembly of aluminum and silicon into the desired zeolite structure.
3Reliability
If post-synthetic treatment is used to convert borosilicate SSZ-33 to aluminosilicate SSZ-33, then the desired catalytic activity is achieved, but the process complexity increases
Solution Approach 1:
The patent performs preliminary action by incorporating aluminum into the zeolite framework during the direct synthesis step, rather than performing post-synthetic conversion. The structure-directing agent facilitates aluminum incorporation during crystallization, eliminating the need for subsequent post-synthetic treatment steps and reducing overall process 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
This approach successfully synthesizes aluminosilicate SSZ-33 with specific X-ray diffraction patterns and composition, enabling its use in catalytic reactions with enhanced framework acid sites.
Implementation Method 1
contacting under crystallization conditions: (1) at least one source of silicon; (2) at least one source of aluminum; (3) hydroxide ions; and (4) a 1,1′-(pentane-1,5-diyl)bis(3-methylcyclohexyl)piperidinium dication
Implementation Method 2
maintaining the reaction mixture under conditions sufficient to form crystals of the zeolite
Data Source
AI summary
Aluminosilicate zeolite SSZ-33 is directly prepared using a 1,1′-(pentane-1,5-diyl)bis(3-methylcyclohexyl)piperidinium dication as a structure directing agent.