Azeotropic Fraction Purification for N,N-Dimethylaminoethyl Acrylate Synthesis
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Solution Overview
Problem
The challenge is to effectively purify the azeotropic fraction generated during the synthesis of N,N-dimethyl aminoethyl acrylate to prevent contamination of alkyl acrylate with acetaldehyde and dialkoxyethane, which complicates recycling and results in heavily contaminated alkyl acrylate production due to the close boiling points of these compounds.
Innovation Solution
A method involving a two-step distillation process where the azeotropic fraction is first distilled above the transesterification reactor, followed by a second distillation column to separate acetaldehyde and dialkoxyethane, or direct distillation in a column with adjusted conditions to remove acetaldehyde and dialkoxyethane, ensuring minimal loss of alkyl acrylate and alcohol, or converting dialkoxyethane to acetaldehyde using water and an acid catalyst for further distillation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the azeotropic fraction is recycled directly to the alkyl acrylate production unit, then productivity is improved through continuous operation, but the lower acrylate becomes heavily contaminated with dialkoxyethane due to acetaldehyde transformation
Solution Approach 1:
The patent applies preliminary action by removing acetaldehyde from the azeotropic fraction through a dedicated distillation column before recycling the fraction to the alkyl acrylate production unit. This preventive measure eliminates the source of dialkoxyethane contamination before it can occur during recycling, allowing continuous operation without compromising product purity
Solution Approach 2:
The patent extracts the harmful acetaldehyde component from the azeotropic fraction using a separate distillation column. By isolating and removing acetaldehyde before recycling, the system prevents contamination while maintaining continuous production flow
2Manufacturing precision
If simple reduction using reducing agents is used to eliminate acetaldehyde, then acetaldehyde removal is achieved, but large amounts of Michael adducts form causing loss of alkyl acrylate and lower alcohol
Solution Approach 1:
The patent replaces chemical reduction methods with a mechanical/physical separation method - distillation. By using a distillation column to remove acetaldehyde based on volatility differences, the system achieves effective acetaldehyde elimination without the unwanted side reactions and material losses associated with chemical reducing agents
Solution Approach 2:
The patent changes the approach from chemical transformation to physical separation by exploiting differences in boiling points. The distillation process separates acetaldehyde from the azeotropic fraction based on volatility parameters, avoiding chemical reactions that would consume valuable materials
3Manufacturing precision
If a two-step distillation process or direct distillation with adjusted conditions is used to separate acetaldehyde and dialkoxyethane, then purity of recycled fraction is improved, but device complexity increases
Solution Approach 1:
The patent segments the distillation process into two functional parts: the existing distillation column that produces the azeotropic fraction, and a second dedicated column that removes acetaldehyde. This segmentation allows each column to be optimized for its specific function, achieving high purity through specialized separation rather than attempting complex multi-function operation in a single column
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 allows for the recycling of a purified alkyl acrylate/alcohol fraction, reducing dialkoxyethane contamination and maintaining high recovery of alkyl acrylate, thereby ensuring economic and efficient recycling to the alkyl acrylate production unit.
Implementation Method 1
a method involving a two-step distillation process where the azeotropic fraction is first distilled above the transesterification reactor, followed by a second distillation column to separate acetaldehyde and dialkoxyethane
Implementation Method 2
converting dialkoxyethane to acetaldehyde using water and an acid catalyst for further distillation
Data Source
AI summary
The invention relates to a method for producing N,N-dimethylaminoethyl acrylate by the transesterification reaction of an alykl acrylate by N1N-dimethylaminoethanol, and more particularly relates to a method for purifying the azeotropic fraction generated during said reaction, thereby enabling the recycling thereof on the alkyl acrylate production unit. The aim of the method of the invention is in particular to remove the acetaldehyde and the dialkoxyethane contained in the azeotropic fraction, either by the direct distillation of the azeotropic fraction or by the distillation of the aqueous phase resulting from the water scrubbing of the azeotropic fraction.