Solidothermal Synthesis of Boron-Containing MWW Zeolites
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Solution Overview
Problem
Current methods for synthesizing zeolites with an MWW framework structure, such as MCM-22, rely on toxic and expensive organotemplates like hexamethyleneimine, and existing solvent-free methods are limited to specific framework types, necessitating an improved process for producing boron-containing zeolites with reduced environmental impact and cost.
Innovation Solution
A solidothermal process is developed to prepare zeolitic materials with an MWW framework structure comprising YO2 and B2O3, involving a mixture of YO2, B2O3, organotemplates, and seed crystals, with a calcination step to form the MWW framework structure, using cycloalkylamines as organotemplates and minimizing water content to less than 35 wt.-%, thereby avoiding the use of solvents and toxic templates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrothermal synthesis methods are used with organotemplates like hexamethyleneimine, then zeolites with MWW framework structure can be synthesized, but the process becomes expensive and environmentally harmful due to toxicity and cost of templates
Solution Approach 1:
The patent removes the harmful organotemplate component from the synthesis system entirely, achieving template-free synthesis of MWW framework zeolites. This extraction of the harmful element eliminates toxicity and cost issues while maintaining synthesis reliability through alternative mechanisms.
Solution Approach 2:
The patent changes the water content parameter to less than 35 wt.-% based on YO2, creating a water-limited solidothermal synthesis environment. This parameter change enables the formation of MWW framework zeolites without requiring organotemplates, resolving the contradiction between synthesis reliability and environmental harm.
2Object-affected harmful factors
If solvent-free synthesis methods are used, then environmental impact and cost are reduced, but the method is limited to specific framework types and cannot produce MWW structure zeolites
Solution Approach 1:
The patent identifies and optimizes specific parameter ranges (water content <35 wt.-%, temperature 80-250°C, time 1-30 days) that enable solidothermal synthesis to produce MWW framework zeolites. This parameter optimization expands the versatility of solvent-free methods while maintaining environmental benefits.
Solution Approach 2:
The patent uses composite starting materials including metal oxides (YO2), boron oxide (B2O3), and seed crystals in specific combinations. This composite approach enables the formation of complex MWW framework structures through solid-state reactions without requiring solvents or organotemplates.
3Object-affected harmful factors
If water content is reduced to less than 35 wt.-%, then the synthesis becomes more environmentally friendly and cost-effective, but the crystallization process becomes more difficult to control
Solution Approach 1:
The patent establishes specific parameter ranges (water <35 wt.-%, temperature 80-250°C, time 1-30 days) that simplify control of the solidothermal process. Within these optimized parameters, the synthesis becomes more predictable and easier to control despite reduced water content, resolving the apparent contradiction.
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 enables the efficient synthesis of boron-containing zeolites with a high yield, reducing water pollution and production costs, while allowing for the production of zeolites with a wide range of framework structures, including B-MCM-22, under solvent-free conditions.
Implementation Method 1
crystallizing the mixture obtained in (i) for obtaining a layered precursor of the MWW framework structure
Implementation Method 2
calcining the layered precursor obtained in (ii) for obtaining the zeolitic material having an MWW framework structure
Data Source
AI summary
The present invention relates to a process for the production of a zeolitic material having an MWW framework structure comprising YO2 and B2O3, wherein Y stands for a tetravalent element, said process comprising(i) preparing a mixture comprising one or more sources for YO2, one or more sources for B2O3, one or more organotemplates, and seed crystals,(ii) crystallizing the mixture obtained in (i) for obtaining a layered precursor of the MWW framework structure,(iii) calcining the layered precursor obtained in (ii) for obtaining the zeolitic material having an MWW framework structure,wherein the one or more organotemplates have the formula (I)R1R2R3N (I)wherein R1 is (C5-C8)cycloalkyl, andwherein R2 and R3 are independently from each other H or alkyl, andwherein the mixture prepared in (i) and crystallized in (ii) contains 35 wt.-% or less of H2O based on 100 wt.-% of YO2 contained in the mixture prepared in (i) and crystallized in (ii), as well as to a synthetic boron-containing zeolite which is obtainable and/or obtained according to the inventive process and to its use.