ZSM-5 Catalyst Stabilization for Methyl Acrylate Production
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Solution Overview
Problem
Current methods for producing methyl acrylate from methyl lactate using catalysts are prone to fast deactivation and result in low yields, unlike the more studied conversion of lactic acid to acrylic acid, which requires different catalysts and reaction conditions.
Innovation Solution
A process involving a ZSM-5 catalyst with a specific SiO2/Al2O3 ratio, potassium form, and high potassium exchange degree, used in the presence of methanol as a solvent, which stabilizes the catalyst and increases selectivity towards methyl acrylate with minimal acrylic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used for converting methyl lactate to methyl acrylate, then the reaction can proceed, but the catalyst deactivates rapidly and yields are low
Solution Approach 1:
The patent changes the chemical composition parameters of the catalyst by incorporating specific metal salts (potassium carbonate, cesium carbonate, potassium hydroxide, or cesium hydroxide) in controlled amounts (0.1-10 wt% based on zeolite weight). This parameter modification transforms the catalyst from rapidly deactivating conventional forms to stable high-yield forms that maintain activity throughout the reaction process.
Solution Approach 2:
The patent creates a composite catalyst system by combining zeolite (ZSM-5, beta-zeolite, or Y-zeolite) with specific metal salts. This composite structure synergistically combines the acid-catalytic properties of zeolite with the stabilizing effects of alkali/alkaline earth metal salts, achieving both high methyl acrylate yield and sustained catalyst stability that neither component achieves alone.
2Productivity
If lactic acid conversion studies are focused on, then acrylic acid production is achieved, but decomposition pathways into acetaldehyde and carbon oxides remain favorable competing reactions
Solution Approach 1:
The patent modifies the catalytic parameters by using specific metal salts (potassium carbonate, cesium carbonate, potassium hydroxide, or cesium hydroxide) incorporated into zeolite structures. These parameter changes alter the reaction pathway selectivity, suppressing decomposition reactions that produce acetaldehyde and carbon oxides while promoting the desired dehydration pathway to methyl acrylate, thereby increasing acrylates yield while minimizing harmful decomposition products.
3Productivity
If ZSM-5 catalyst with low silica/alumina ratio is used, then acrylic acid selectivity and yield improve, but catalyst stability decreases
Solution Approach 1:
The patent creates a composite catalyst system by combining zeolite (ZSM-5, beta-zeolite, or Y-zeolite) with specific metal salts (potassium carbonate, cesium carbonate, potassium hydroxide, or cesium hydroxide). This composite structure synergistically combines the acid-catalytic properties of zeolite with the stabilizing effects of alkali/alkaline earth metal salts, achieving both high methyl acrylate yield and sustained catalyst stability that neither component achieves alone.
Solution Approach 2:
The patent changes the chemical composition parameters of the catalyst by incorporating specific metal salts (potassium carbonate, cesium carbonate, potassium hydroxide, or cesium hydroxide) in controlled amounts (0.1-10 wt% based on zeolite weight). This parameter modification transforms the catalyst from rapidly deactivating conventional forms to stable high-yield forms that maintain activity throughout the reaction process.
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
The process achieves high selectivity and stability for methyl acrylate production, with selectivity above 75% and maintaining stability for over 24 hours, significantly improving upon previous low-yield methods.
Implementation Method 1
methyl lactate is contacted with a ZSM-5 catalyst in the presence of methanol
Implementation Method 2
methyl lactate is contacted with a ZSM-5 catalyst in the presence of methanol
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 2(a)1~2(a)2
AI summary
The present invention is directed to a process for the production of methyl acrylate wherein methyl lactate is contacted with a ZSM-5 catalyst in the presence of methanol. It was found that the presence of methanol is essential to obtain a selective process with a high yield. With the process according to the invention methyl acrylate may be obtained as the major product of the reaction, especially if methanol is used as solvent instead of water, while acrylic acid is detected in minor quantity (usually below 10C%, but often below 5 C%). Methanol may be used as the sole solvent in the process, but preferably also a small amount of water is present in the solvent. In one aspect of the invention, between 1 and 25 wt% of water, based on the total amount of solvent is present.