Coherently Grown Composite Molecular Sieves Synthesis
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Solution Overview
Problem
The synthesis of molecular sieves with complex organoammonium structure directing agents (SDAs) is lengthy and costly, and existing composite materials with intergrown phases are often disordered, lacking coherency and requiring expensive purification steps and organic solvents.
Innovation Solution
A method for synthesizing coherently grown composites of aluminophosphate and silicoaluminophosphate molecular sieves using 1-oxa-4-azonium cyclohexane derivatives, which allows for the formation of seamless cage structures without binders and reduces the need for organic solvents, enabling the production of materials with varying silicon, aluminum, and phosphorus concentrations for tailored acid site densities and strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex organoammonium structure directing agents are used to synthesize molecular sieves, then the pore structure and catalytic properties are improved, but the synthesis time and cost increase significantly
Solution Approach 1:
The patent changes the chemical parameters of the structure directing agent from complex organoammonium compounds to simple morpholine derivatives. This parameter change maintains the ability to direct pore structure formation while dramatically reducing synthesis complexity and time, resolving the contradiction between structure quality and synthesis efficiency
Solution Approach 2:
The patent replaces expensive, complex organoammonium SDAs with inexpensive, readily available morpholine derivatives. The simple chemical structure and commercial availability of morpholine-based agents reduce both material cost and synthesis time, directly addressing the contradiction between reliability and time loss
2Adaptability or versatility
If composite molecular sieves with intergrown phases are synthesized, then the functional properties are enhanced, but the structural order and coherency deteriorate
Solution Approach 1:
The patent uses morpholine derivatives as pre-designed structure directing agents that template the formation of specific zeotype structures (CHA, AFX, LEV, ERI) before they intergrow. This preliminary structuring action ensures that when phases intergrow, they maintain coherent interfaces and structural order, resolving the contradiction between functional versatility and compositional stability
Solution Approach 2:
The patent creates composite molecular sieves containing multiple zeotype phases (CHA, AFX, LEV, ERI) that are coherently intergrown at the nanoscale. The composite structure provides enhanced functional properties through phase synergies while the coherent interfaces maintain structural order, directly addressing the contradiction between adaptability and stability
3Reliability
If traditional synthesis methods are used, then the molecular sieve structure is formed, but expensive purification steps and organic solvents are required
Solution Approach 1:
The patent employs morpholine derivatives that serve dual functions: as structure directing agents during synthesis and as easily removable byproducts after reaction. The simplicity of the morpholine structure allows for self-service purification where the SDA can be removed by simple washing or heating without requiring expensive chromatographic or solvent-based purification steps, resolving the contradiction between reliable structure formation and substance loss
Solution Approach 2:
The patent extracts the essential function of structure direction from complex organoammonium compounds and isolates it in simple morpholine derivatives. This extraction allows the SDA to perform its structuring function while being easily separable from the final product through simple extraction or decomposition, eliminating the need for expensive purification processes
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 enables the creation of thermally stable, coherently grown composite molecular sieves with enhanced micropore volume and tailored properties, overcoming the limitations of disordered intergrown phases and costly synthesis methods, while avoiding the need for expensive purification steps and organic solvents.
Implementation Method 1
The structure directing agents reside in the pores of the molecular sieve and are largely responsible for the particular structure that is ultimately formed
Implementation Method 2
A method for synthesizing coherently grown composites of aluminophosphate and silicoaluminophosphate molecular sieves using 1-oxa-4-azonium cyclohexane derivatives, which allows for the formation of seamless cage structures
Implementation Method 3
coherently grown composites of two zeotypes having a crystalline three-dimensional framework... the two crystalline phases are coherently and rationally joined together in a single material
Implementation Method 4
Synthetically, these molecular sieves are prepared via hydrothermal synthesis employing suitable sources of Si, Al, P, and structure directing agents
Data Source
AI summary
Coherently grown composites of two zeotypes are described. The coherently grown composites have a crystalline three-dimensional framework of at least AlO2 and PO2 tetrahedral units. The two zeotypes are selected from the group consisting of AFX, LEV, CHA, and ERI. Methods of making the coherently grown composites are also described.