SSZ-117x Molecular Sieve Acidity via Boron-to-Aluminum Exchange
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Solution Overview
Problem
There is a need for new zeolitic materials with increased acidity to enhance the performance of organic compound conversion and sorption processes, as existing materials often result in amorphous phases leading to a loss of aluminum acid sites.
Innovation Solution
The synthesis of SSZ-117x molecular sieve is achieved using a boron pathway with N,N,N,3,5-pentamethyladamantan-1-ammonium cations as a structure directing agent, followed by boron replacement with aluminum to increase acid sites, resulting in a molecular sieve with enhanced acidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synthesis methods are used to prepare molecular sieves, then the synthesis process is straightforward, but amorphous phases occur leading to loss of aluminum acid sites and reduced acidity
Solution Approach 1:
The patent applies preliminary action by first synthesizing the molecular sieve framework with boron incorporated during the crystallization phase, then subsequently replacing boron with aluminum through ion exchange or hydrothermal treatment. This two-step approach prevents the formation of amorphous phases during initial synthesis while ensuring high aluminum content and acidity in the final product, thereby resolving the contradiction between reliable acidity and ease of manufacture
Solution Approach 2:
The patent utilizes parameter changes by modifying the chemical composition parameters during synthesis - specifically controlling the SiO2/Al2O3 ratio to be at least 300 and incorporating boron as an intermediate element. By changing the compositional parameters and using boron as a temporary framework component that is later replaced with aluminum, the method achieves high crystallinity and acidity while maintaining a feasible synthesis process
2Reliability
If the SiO2/Al2O3 ratio is increased to improve catalytic performance, then acid sites are enhanced, but the structural stability and phase purity become more difficult to maintain
Solution Approach 1:
The patent employs boron as an intermediary element during the synthesis process. Boron acts as a mediator that facilitates the formation of a stable crystalline framework at high SiO2/Al2O3 ratios (≥300). The boron-containing intermediate phase maintains structural stability during crystallization, and subsequent boron replacement with aluminum preserves this stability while achieving the desired high acidity and catalytic performance
3Quantity of substance
If aluminum content is increased to provide more acid sites, then catalytic activity improves, but the risk of forming amorphous phases increases
Solution Approach 1:
The patent applies preliminary action by first establishing a stable crystalline framework using boron during synthesis, then subsequently introducing aluminum to replace boron in the framework. This sequence ensures that the crystalline structure is already established and stable before aluminum incorporation, preventing amorphous phase formation even when achieving high aluminum content and acid site density
Solution Approach 2:
The patent utilizes parameter changes by controlling the final aluminum content to achieve high acid site density while maintaining the SiO2/Al2O3 ratio at least 300. By adjusting compositional parameters and using the boron-intermediate approach, the method achieves high aluminum content with improved crystalline structure and prevents amorphous phase 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
The SSZ-117x molecular sieve exhibits increased acid sites, improving catalytic characteristics and catalyzing various organic compound conversion processes, including cracking, hydrocracking, and isomerization, with enhanced stability and efficiency.
Implementation Method 1
The synthesis is conducted through a boron pathway, and the final molecular sieve contains some boron. The method comprises (a) providing a reaction mixture comprising: (1) a FAU framework type zeolite; (2) a source of germanium; (3) a source of boron; (4) N,N,N,3,5-pentamethyladamantan-1-ammonium hydroxide (Q); (5) a source of fluoride ions; and (6) water, and (b) the reaction mixture is then subjected to crystallization conditions sufficient to form crystals of a SSZ-117x boron molecular sieve.
Implementation Method 2
The SDA can be removed by calcination, or by ozone treatment, e.g., at 150° C.
Implementation Method 3
Once the SDA has been removed, the boron containing SSZ-117x molecular sieve is treated to replace boron in the framework with aluminum. A molecular sieve with increased acid sites is then recovered.
Data Source
AI summary
A novel synthetic crystalline aluminogermanosilicate molecular sieve material, designated SSZ-117x, is provided which exhibits increased acidity. The SSZ-117x can be synthesized using N,N,N,3,5-pentamethyladamantan-1-ammonium cations as a structure directing agent. The synthesis employs a boron pathway to achieve increased acid sites. The SSZ-117x of increased acidity may be used in organic compound conversion reactions and/or sorptive processes.