Tin-Containing BEA Zeolite Synthesis via Boron-Precrystallization
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Solution Overview
Problem
Existing methods for preparing tin-containing zeolites with a BEA framework structure are hindered by long synthesis times and the need for costly crystallization auxiliaries like HF or templating agents, and industrial-scale fluoride-free routes are complex and undesirable.
Innovation Solution
A process involving the hydrothermal synthesis of a tin-containing zeolite with a BEA framework structure using a synthesis mixture containing both a tin source and a boron source, followed by deboronation, where a precursor is precrystallized with a boron source, silicon source, and BEA structure directing agent, then subjected to hydrothermal conditions with a tin source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrothermal treatment is used to incorporate tin into zeolitic framework, then tin-containing zeolite with BEA structure is obtained, but synthesis time period becomes long
Solution Approach 1:
The patent applies preliminary action by pre-forming the zeolitic framework structure with boron incorporation before introducing tin. The process first synthesizes a boron-containing zeolitic material with BEA framework, then performs a second hydrothermal treatment to incorporate tin into the pre-formed framework. This two-stage approach allows the framework to be established first, making the subsequent tin incorporation more efficient and reducing overall synthesis time while maintaining structural integrity.
2Reliability
If crystallization auxiliaries such as HF or templating agents are employed, then zeolite crystallization is achieved, but process cost increases
Solution Approach 1:
The patent applies the taking out principle by removing harmful and expensive crystallization auxiliaries (HF and templating agents) from the synthesis process. Instead, it uses a fluoride-free system with controlled pH and specific reactant ratios to achieve crystallization. The process extracts the need for dangerous chemicals while maintaining effective zeolite formation through alternative mechanisms involving boron-silicon interaction and controlled hydrothermal conditions.
Solution Approach 2:
The patent replaces expensive and hazardous crystallization auxiliaries with inexpensive, environmentally benign alternatives. The synthesis uses readily available starting materials such as sodium borate, silica source, and organic base (e.g., ammonia or alkylamines) that can be easily removed. This substitution dramatically reduces both material costs and waste treatment costs while maintaining product quality.
3Device complexity
If direct hydrothermal synthesis is performed without precrystallization, then synthesis procedure is simplified, but synthesis time increases and crystallization quality decreases
Solution Approach 1:
The patent applies segmentation by dividing the synthesis process into two distinct stages: (1) precrystallization stage where boron-containing zeolitic framework is formed, and (2) tin incorporation stage where tin is introduced into the pre-formed framework. This segmentation allows each stage to be optimized independently - the first stage focuses on framework formation with boron, while the second stage专注于 tin incorporation - resulting in reduced total synthesis time and improved crystallization quality compared to a single-step approach.
4Stability of the object's composition
If boron is present in the zeolitic framework, then framework stability is improved, but product purity for catalytic applications decreases
Solution Approach 1:
The patent applies preliminary action by incorporating boron into the zeolitic framework during the precrystallization stage before tin incorporation. This ensures boron is properly integrated into the framework structure to provide stability. Afterward, a deboronation treatment is performed as a preliminary step before final catalytic application, removing excess boron while preserving the stable framework structure. This sequence allows both framework stability and product purity to be achieved.
Solution Approach 2:
The patent applies discarding and recovering by performing a controlled deboronation step after tin incorporation. Excess boron that was incorporated during precrystallization is selectively removed through acid treatment or other deboronation methods, while the boron that is structurally integrated into the framework remains to provide stability. This selective removal process achieves high product purity for catalytic applications while maintaining framework integrity.
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 method reduces synthesis time, eliminates the need for costly auxiliaries, and produces a tin-containing zeolite with improved properties suitable for catalytic applications, such as Baeyer-Villiger-type oxidation reactions, while allowing for the removal of boron to produce a boron-free variant.
Implementation Method 1
subjecting the aqueous synthesis mixture provided in (i) to hydrothermal crystallization conditions, obtaining a tin-containing zeolitic material having framework type BEA comprised in its mother liquor
Data Source
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AI summary
A process for preparing a tin-containing zeolitic material having framework type BEA, comprising providing an aqueous synthesis mixture comprising a boron source, a silicon source, and a BEA structure directing agent; subjecting the synthesis mixture provided in to hydrothermal pre-crystallization conditions; adding the tin source to the obtained mixture; subjecting the obtained aqueous synthesis mixture to hydrothermal crystallization conditions, obtaining a tin-containing zeolitic material having framework type BEA comprised in its mother liquor.