Phosphorus-Free Cu-CHA Zeolite Synthesis via Single-Stage Crystallization
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Solution Overview
Problem
Current methods for preparing copper-containing zeolitic materials with a CHA framework structure often require multiple stages and involve the use of phosphorus, which complicates the process and reduces efficiency, especially in achieving high Cu content and optimal Si:Al ratios.
Innovation Solution
A process involving a single hydrothermal crystallization stage using an aqueous solution with sources for Al, Si, and Cu, without phosphorus, to produce zeolitic materials with a high Si:Al ratio and high Cu content, utilizing specific structure directing agents and controlled pH and temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple stages are used to prepare copper-containing zeolitic materials with CHA framework structure, then Cu content and Si:Al ratio can be optimized, but the process complexity increases and efficiency decreases
Solution Approach 1:
The patent combines multiple process stages (zeolite synthesis and copper incorporation) into a single hydrothermal crystallization stage. By including copper sources in the initial synthesis mixture, the process achieves both zeolite framework formation and copper incorporation simultaneously, eliminating sequential ion-exchange steps and reducing overall process complexity while maintaining control over Cu content and Si:Al ratio
Solution Approach 2:
The patent incorporates copper sources into the synthesis mixture before the hydrothermal crystallization begins. This preliminary incorporation of copper allows the metal to be integrated into the zeolite framework during crystal growth, rather than requiring post-synthesis ion-exchange treatments, thereby simplifying the overall process
2Reliability
If phosphorus is used in the synthesis process, then certain zeolitic structures can be formed, but the process becomes more complex and phosphorus contamination occurs
Solution Approach 1:
The patent removes phosphorus from the synthesis system entirely. By using alternative structure-directing agents and synthesis conditions that do not require phosphorus, the process eliminates phosphorus contamination while still achieving successful formation of the CHA framework structure through copper-containing zeolite synthesis
Solution Approach 2:
The patent changes the chemical parameters of the synthesis system by eliminating phosphorus-containing compounds. Instead, it uses copper sources (such as copper nitrate, copper acetate, or copper chloride) in combination with appropriate structure-directing agents and alkaline conditions to achieve the desired zeolite structure without phosphorus contamination
3Quantity of substance
If ion-exchange is used to incorporate copper into zeolites, then Cu content can be increased, but additional process stages are required reducing efficiency
Solution Approach 1:
The patent merges the copper incorporation step with the zeolite synthesis step by including copper sources in the initial synthesis mixture. This allows copper to be incorporated into the zeolite framework during crystal growth itself, eliminating the need for separate ion-exchange stages and improving overall process efficiency while achieving high Cu content
Solution Approach 2:
The patent performs copper incorporation preliminarily during the synthesis stage rather than as a subsequent treatment. By having copper sources present from the beginning of hydrothermal crystallization, the copper is integrated into the growing crystal structure, avoiding the need for additional ion-exchange processing steps
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 process efficiently produces copper-containing zeolitic materials with a CHA framework structure, achieving high Cu content and optimal Si:Al ratios in a single stage, reducing complexity and increasing efficiency while avoiding phosphorus contamination.
Implementation Method 1
hydrothermal crystallization of the aqueous solution according to (i) which does not contain a phosphorus source, obtaining a suspension containing the copper containing zeolitic material having CHA framework structure
Data Source
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AI summary
A process for the preparation of a copper containing zeolitic material having CHA framework structure and a composition comprising the molar ratio (n YO2) : X2O3 wherein X is a trivalent element, preferably Al, Y is a tetravalent element, preferably Si, and wherein n is preferably at least 20, the process comprising the preparation of an phosphor-free aqueous solution containing at least one source for X2O3 and at least one source for YO2, at least one structure directing agent suitable for the preparation of a zeolitic material having CHA framework structure, and at least one Cu source, and the process further comprising the hydrothermal crystallization of said aqueous solution obtaining a suspension containing the copper containing zeolitic material having CHA framework structure.