Methacrolein Distillation for MMA Yield and Catalyst Life
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Solution Overview
Problem
Conventional processes for producing methyl methacrylate (MMA) face issues such as low yields, high by-product formation, excessive waste generation, and catalyst deactivation due to elevated water content and formaldehyde reactivity, leading to increased costs and maintenance needs.
Innovation Solution
A novel process involving the preparation of methacrolein from propanal and formaldehyde, followed by distillation in the presence of methanol, and subsequent oxidative esterification with oxygen using a heterogeneous noble metal catalyst, which includes an additional distillation step to reduce methacrylic acid content and extend catalyst life, thereby increasing yield and reducing auxiliary base consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional gas phase oxidation of isobutylene or TBA is used to produce methacrolein, then the process can be implemented on production scale, but yields are below 90% and complex isolation steps are required due to by-product formation
Solution Approach 1:
The patent changes the physical state parameter from gas phase to liquid phase oxidation, and modifies the catalyst system from conventional heterogeneous catalysts to a specific cobalt-manganese-bromide catalyst system in liquid phase, achieving higher yields (above 90%) and simplified isolation steps
Solution Approach 2:
The patent replaces the conventional gas phase mechanical oxidation process with a liquid phase chemical oxidation process using a specific catalyst system, substituting the oxidation mechanism to achieve better product formation and reduce by-products
2Ease of operation
If water content is not reduced in methacrolein before oxidative esterification, then the process is simpler, but methacrylic acid formation increases and catalyst service life decreases
Solution Approach 1:
The patent performs preliminary water removal from methacrolein before the oxidative esterification step, eliminating the harmful effect of water on catalyst life and methacrylic acid formation, thereby allowing the use of simpler distillation processes without compromising catalyst performance
3Ease of operation
If formaldehyde and conversion products are not removed before oxidative esterification, then the process is simpler, but catalyst deactivation occurs and plant occupation time decreases
Solution Approach 1:
The patent performs preliminary removal of formaldehyde and its conversion products (oligomers and polymers) from methacrolein before oxidative esterification, preventing catalyst deactivation and extending plant occupation time, while using simpler distillation processes
4Productivity
If acid and amine catalysts are used in high amounts for Mannich reaction, then the reaction proceeds efficiently, but large amounts of waste products are generated
Solution Approach 1:
The patent changes the catalyst system from conventional acid-amine catalysts requiring high amounts to a catalytic system using minimal amounts of acid and amine, combined with preliminary water removal, achieving both efficient reaction and reduced waste product formation
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 enhances MMA yield, reduces waste and catalyst deactivation, and allows for more efficient operation with lower energy requirements and environmental impact, while minimizing the formation of harmful by-products and extending plant occupation time.
Implementation Method 1
isolating crude methacrolein by distillation in a first distillation column
Implementation Method 2
oxidatively esterifying the methacrolein obtained from step C) with methanol and oxygen in the presence of a heterogeneous noble metal-containing oxidation catalyst
Implementation Method 3
oxidatively esterifying the methacrolein obtained from step C) with methanol and oxygen
Data Source
AI summary
The present invention relates to a process for preparing methyl methacrylate by direct oxidative esterification of methacrolein and the preparation of methacrolein. It is a feature of this novel process that it was possible to distinctly increase the yield and the efficiency of the process compared to the prior art through a sequence of different distillation steps.