Egg-Shell Catalyst Leaching in MMA Synthesis
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Solution Overview
Problem
Existing processes for catalytic oxidative esterification of methacrolein to methyl methacrylate face challenges in maintaining high yield and selectivity, particularly in retaining catalyst shape, structure, and active component distribution, especially under intense stirring conditions, leading to reduced activity and increased formation of unwanted products.
Innovation Solution
A process using an egg-shell catalyst with gold and a second element like Ni, Co, Fe, or Zn supported on SiO2 and Al2O3, with a compound containing these elements being at least partially soluble in the reaction mixture to maintain the catalyst's activity and selectivity by preventing leaching of active components and replenishing them as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If intense stirring conditions are applied to ensure good mixing and heat transfer in the oxidative esterification process, then reaction efficiency is improved, but catalyst structure and active component distribution deteriorate due to mechanical abrasion and leaching
Solution Approach 1:
The patent applies beforehand cushioning by introducing a soluble compound containing the second element (Ni, Co, Fe, Zn, or Ti) into the reaction mixture before catalyst degradation occurs. This compound acts as a protective reservoir that replenishes leached active components, cushioning against the mechanical stress of intense stirring and preventing permanent catalyst structure deterioration.
Solution Approach 2:
The patent implements feedback by using the soluble compound as a dynamic reservoir that responds to catalyst degradation. The compound continuously replenishes leached metal ions in the reaction mixture, creating a self-regulating system that maintains catalyst activity and structure under intense stirring conditions without requiring external intervention.
2Productivity
If the catalyst operates for extended periods to increase productivity, then production volume increases, but catalyst activity decreases due to leaching of active components
Solution Approach 1:
The patent ensures continuity of useful action by introducing the soluble compound containing the second element into the reaction mixture. This compound continuously replenishes leached active components throughout the extended operation period, maintaining constant catalyst activity and enabling prolonged productive operation without degradation.
Solution Approach 2:
The patent applies self-service by using the soluble compound as an autonomous replenishment system. The compound automatically replaces leached metal ions in the catalyst structure without external intervention, allowing the catalyst to maintain its own activity levels throughout extended operation periods.
3Device complexity
If conventional catalysts are used without soluble compound addition, then process simplicity is maintained, but selectivity deteriorates due to increased formation of unwanted products from catalyst degradation
Solution Approach 1:
The patent uses the soluble compound as an intermediary substance that mediates between the catalyst and the reaction environment. This intermediary replenishes leached metal ions and prevents catalyst degradation, thereby eliminating the formation of unwanted products while adding minimal complexity to the 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
This approach maintains high activity and selectivity of the egg-shell catalyst, reduces the formation of unwanted products, and extends the catalyst's lifetime by preventing metal ion loss and re-depositing active components, thereby optimizing the production of methyl methacrylate.
Implementation Method 1
a compound, comprising Ni, Co, Fe, Zn and/or Ti, which is at least partially soluble in the reaction mixture
Implementation Method 2
re-depositing active components
Implementation Method 3
catalytic oxidative esterification of methacrolein with methanol and oxygen
Implementation Method 4
heterogeneous egg-shell catalyst comprising gold metal and an oxide of at least one second element
Data Source
AI summary
Process for catalytic oxidative esterification of methacrolein with methanol and oxygen to methyl methacrylate in the presence of a heterogeneous egg-shell catalyst comprising gold metal and an oxide of at least one second element selected from Ni, Co, Fe, Zn and/or Ti supported on a support material comprising SiO2, Al2O3 and at least one basic element oxide, characterized in that the process is carried out in the presence of at least one compound, comprising Ni, Co, Fe, Zn and/or Ti, which is soluble in the reaction mixture under process conditions.