Reactive Absorption for Methylmercaptopropionaldehyde Production
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Solution Overview
Problem
Current processes for producing methyl mercaptopropionaldehyde (MMP) from gaseous acrolein and methyl mercaptan are inefficient, requiring multiple stages, high investment and operating costs, and result in significant losses of valuable materials due to distillation and separate water condensation steps.
Innovation Solution
A process that absorbs gaseous acrolein into a mixture of methyl mercaptopropionaldehyde, methyl mercaptan, and hemithioacetal in a reactive absorber, where acrolein reacts with methyl mercaptan to form MMP, while removing impurities and by-products in a single step, eliminating the need for separate water condensation and minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a two-stage process with separate absorption and reaction steps is used, then the conversion of acrolein can be improved, but the device complexity and operating costs increase due to multiple containers and recycling requirements
Solution Approach 1:
The patent combines the absorption of gaseous acrolein and the reaction with methyl mercaptan into a single reactive absorption step within one absorber column. The absorption medium contains methyl mercaptopropionaldehyde, methyl mercaptan, and hemithioacetal, allowing simultaneous mass transfer and chemical reaction. This eliminates the need for separate absorption and reaction stages, reducing equipment complexity while maintaining high conversion efficiency.
Solution Approach 2:
The absorption medium serves multiple functions simultaneously: it acts as the absorbing solvent for gaseous acrolein, provides the reactant (methyl mercaptan and hemithioacetal) for the chemical reaction, and facilitates the formation of methyl mercaptopropionaldehyde. This multi-functionality eliminates the need for separate process stages and reduces equipment requirements.
2Manufacturing precision
If distillation-processed methyl mercaptan is used, then the purity of the reactant is improved, but the loss of valuable materials increases due to distillation residues requiring disposal
Solution Approach 1:
The patent changes the purity requirement parameter for methyl mercaptan from high (distillation-processed) to moderate (crude), demonstrating that high purity is not necessary for successful reaction. By adjusting the process parameters to accommodate crude methyl mercaptan containing water and by-products, the need for energy-intensive distillation is eliminated, thereby preventing material loss.
Solution Approach 2:
The patent converts the previously harmful effect of impurities in crude methyl mercaptan into a beneficial feature. The impurities (water and by-products) are no longer treated as contaminants requiring removal but are accepted as part of the reactant mixture. This approach eliminates distillation losses and transforms the waste disposal problem into a sustainable process feature.
3Manufacturing precision
If separate water condensation step is added, then the product purity is improved, but the investment and operating costs increase
Solution Approach 1:
The patent merges the water management function into the reactive absorption process. Water formed during the reaction and present in crude methyl mercaptan is handled within the absorber column through the equilibrium between methyl mercaptan, hemithioacetal, and water. This eliminates the need for separate condensation equipment and steps while maintaining product quality.
Solution Approach 2:
The absorber column performs multiple functions simultaneously: absorbing gaseous acrolein, providing reactants for the chemical reaction, managing water formed during reaction, and producing the final product. This multi-functionality eliminates the need for separate water condensation equipment and reduces overall process complexity.
4Productivity
If multiple process stages are used, then the yield can be optimized, but the loss of time increases due to multiple separation and treatment steps
Solution Approach 1:
The patent implements continuous reactive absorption where gaseous acrolein is continuously absorbed and reacted with methyl mercaptan in the liquid phase within a single absorber column. The process maintains continuous operation without interruption for separation, condensation, or other intermediate steps, thereby achieving high yield while minimizing process time.
Solution Approach 2:
The patent merges absorption, reaction, and product formation into a single continuous process step within the absorber column. By combining these functions that were previously separated into multiple stages, the process eliminates intermediate transfer and separation times while maintaining optimized yield through the reactive absorption mechanism.
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 achieves near 100% MMP yield with reduced losses of educts and target product, simplifying the production by integrating absorption and stripping in a single step, thereby minimizing costs and environmental impact.
Implementation Method 1
gaseous acrolein is absorbed by a mixture containing at least one compound from the group consisting of the hemithioacetal of methyl mercaptopropionaldehyde, methyl mercaptopropionaldehyde and methyl mercaptan
Implementation Method 2
the low-boiling by-products dimethyl sulfide, acetaldehyde, water and dimethyl disulfide are stripped
Implementation Method 3
in this mixture acrolein is reacted with methyl mercaptan and/or the hemithioacetal of methyl mercaptopropionaldehyde in the liquid phase to form methyl mercaptopropionaldehyde
Data Source
Figure 1
AI summary
The present invention relates to a process for preparing methylmercaptopropionaldehyde from gaseous acrolein and methyl mercaptan, characterized in that, in one process step, simultaneously, (a) gaseous acrolein is absorbed from a mixture at least comprising one compound from the group consisting of the hemithioacetal of methylmercaptopropionaldehyde, methylmercaptopropionaldehyde and methyl mercaptan, (b) in this mixture, acrolein is reacted with methyl mercaptan and/or the hemithioacetal of methylmercaptopropionaldehyde to give methylmercaptopropionaldehyde and (c) impurities and by-products are removed from this mixture.