MSE-type zeolite synthesis using tetraethylammonium seed crystals
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Solution Overview
Problem
The high cost of organic structure-directing agents (OSDAs) used in the synthesis of MSE-type zeolites, such as MCM-68, YNU-2, and YNU-3, limits their industrial application due to their complex and expensive nature, and existing methods to produce MSE-type zeolites without OSDAs aim to reduce costs but not effectively utilize inexpensive OSDAs.
Innovation Solution
A method involving the mixing of a silica source, an alumina source, an alkali source, tetraethylammonium ions, and water with an MSE-type zeolite seed crystal, heated in a hermetically sealed environment at 100 to 200°C, to produce MSE-type zeolites using tetraethylammonium ions as an inexpensive OSDA, reducing production time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If expensive organic structure-directing agents (OSDAs) with complex cyclic structures are used for synthesizing MSE-type zeolites, then the zeolite synthesis succeeds with proper structure formation, but the production cost becomes prohibitively high
Solution Approach 1:
The patent replaces expensive, complex cyclic OSDAs with inexpensive tetraethylammonium ions that can be easily discarded after serving their structure-directing function. This substitution dramatically reduces material costs while maintaining the ability to direct zeolite framework formation, directly resolving the contradiction between synthesis reliability and manufacturing cost.
Solution Approach 2:
The patent changes the chemical parameters of the OSDA from complex cyclic structures to simple tetraethylammonium ions, altering the molecular structure, cost, and physical properties while maintaining the essential function of directing zeolite framework formation. This parameter change enables cost-effective production without sacrificing synthesis success.
2Manufacturing precision
If conventional synthesis methods using expensive OSDAs are employed, then MSE-type zeolites are produced with proper crystallinity, but the production time becomes excessively long
Solution Approach 1:
The use of simple tetraethylammonium ions instead of complex OSDAs accelerates the crystallization kinetics, reducing production time while maintaining crystallinity. The simpler molecular structure of the OSDA allows for faster incorporation into the zeolite framework and quicker crystal growth.
3Ease of manufacture
If inexpensive OSDAs are used for MSE-type zeolite synthesis, then production cost decreases, but the ability to direct proper zeolite structure formation becomes insufficient
Solution Approach 1:
The patent identifies tetraethylammonium ions as a cheap OSDA that surprisingly maintains adequate structure-directing ability for MSE-type zeolite formation. The cation's size and charge distribution are sufficient to template the required framework, proving that inexpensive alternatives can replace costly complex OSDAs without completely sacrificing structure formation capability.
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 efficiently produces MSE-type zeolites with a wide selection of seed crystals, reducing production time and costs by using tetraethylammonium ions, while maintaining high purity and crystallinity, making them suitable for industrial use as solid acid catalysts or adsorbents.
Implementation Method 1
heating the reaction mixture to which the seed crystal has been added, at a temperature of 100 to 200°C in a hermetically sealed manner
Implementation Method 2
heating the reaction mixture to which the seed crystal has been added, at a temperature of 100 to 200°C
Data Source
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AI summary
The objective of the invention is to provide an MSE-type zeolite production method such that an MSE-type zeolite can be produced in a comparatively short heating time by using inexpensive tetraethylammonium ion. The production method of the present invention comprises steps of: (1) mixing a silica source, an alumina source, an alkali source, tetraethylammonium ion, and water in such a manner as to yield a reaction mixture of the composition represented by the molar ratios indicated below: SiO2/Al2O3 = between 10 and 100 inclusive (Na2O + K2O)/SiO2 = between 0.15 and 0.50 inclusive K2O/(Na2O + K2O) = between 0.05 and 0.7 inclusive TEA2O/SiO2 = between 0.08 and 0.20 inclusive H2O/SiO2 = between 5 and 50 inclusive; (2) using the MSE-type zeolite as a seed crystal, and adding this seed crystal to the mixture at a proportion of 5 to 30% by mass with respect to the silica component in the reaction mixture; and (3) heating, under hermetic seal at a temperature of 100 to 200°C, the reaction mixture whereto the seed crystal has been added.