C6-C12 Alkyl (Meth)acrylate Purification for Low Acetate Content
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Solution Overview
Problem
Existing processes for producing (meth)acrylic esters face challenges in separating trace amounts of acetic acid by-products, leading to economic losses and the need for costly purification methods to achieve high purity, especially in high (meth)acrylic esters used in the food and cosmetics sectors.
Innovation Solution
A process involving esterification of (meth)acrylic acid with C6-C12 alkyl alcohols, followed by a specific purification method using a low boiler column with rectifying and stripping sections, and an acetate column operated at higher pressure to separate and recycle unconverted alcohol, minimizing acetic ester content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional esterification processes are used to produce (meth)acrylic esters, then the production process is simple, but the crude ester contains trace amounts of acetic acid by-products that are very difficult to separate, leading to economic losses
Solution Approach 1:
The purification process is divided into multiple distillation stages: a first distillation column separates the crude ester into a distillate fraction (containing unreacted alcohol and acetic ester) and a bottoms fraction (purified ester); a second distillation column further purifies the distillate fraction. This segmented approach enables effective separation of trace acetic acid by-products while maintaining process feasibility
Solution Approach 2:
The harmful acetic acid by-products and acetic ester are extracted and removed from the crude (meth)acrylic ester through distillation. The first distillation column removes the distillate fraction containing these impurities, and the second distillation column further extracts acetic ester, leaving purified (meth)acrylic ester with less than 1500 ppm acetic acid by-products
2Manufacturing precision
If the unconverted alcohol fraction is discarded to avoid acetate ester enrichment, then the product purity is improved, but there is economic loss of a valuable product
Solution Approach 1:
Instead of discarding the unconverted alcohol fraction, the process recovers it through distillation. The first distillation column separates and recovers unreacted alcohol in the distillate fraction, which is then reused in subsequent esterification processes. This eliminates economic loss while maintaining product purity through proper waste management
3Manufacturing precision
If multiple distillation columns are used to achieve high purity, then the product quality is improved, but the energy demand increases
Solution Approach 1:
The esterification reaction is optimized to achieve high conversion rates before distillation, reducing the burden on subsequent purification steps. Additionally, the distillation process is designed with efficient heat integration, where the bottoms fraction from the first column feeds into the second column, minimizing the number of independent heating zones required and reducing overall energy consumption
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 (meth)acrylic esters with high purity (>99.7%) and low acetic ester content (<500 ppm), recovering 98% of unreacted alcohol for recycling, while reducing energy consumption and avoiding complex distillation steps.
Implementation Method 1
introducing crude (meth)acrylic ester into the side of a low boiler column with a rectifying section disposed above the feed point of the crude (meth)acrylic ester and a stripping section disposed below the feed point
Implementation Method 2
directing the low boiler fraction to an acetate column, the acetate column being operated at a pressure at least 50 mbar higher than the low boiler column pressure, and separating the low boiler fraction into an alcohol fraction withdrawn at the top of the acetate column and an acetic ester fraction withdrawn at the bottom of the acetate column
Data Source
Figure 1~2
Figure 3
AI summary
A process for the production of C6-C12-alkyl (meth)acrylic esters, comprises an esterification step of esterifying (meth)acrylic acid with an alcohol to obtain a crude (meth)acrylic ester, the (meth)acrylic acid containing trace amounts of acetic acid; and purification steps of purifying the crude (meth)acrylic ester. The purification steps comprise introducing crude (meth)acrylic ester into the side of a low boiler column with a rectifying section disposed above the feed point of the crude (meth)acrylic ester and a stripping section disposed below the feed point; withdrawing purified (meth)acrylic ester from the low boiler column; withdrawing a low boiler fraction from the top of the low boiler column, the low boiler fraction comprising alcohol and acetic ester and less than 10 wt.-% of (meth)acrylic ester; directing the low boiler fraction to an acetate column, the acetate column being operated at a pressure at least 50 mbar higher than the low boiler column pressure, and separating the low boiler fraction into an alcohol fraction withdrawn at the top of the acetate column and an acetic ester fraction withdrawn at the bottom of the acetate column; and recycling the alcohol fraction at least partially to the esterification step; the process comprising no recycle from the acetate column to the low boiler column. The process provides an effective and economically viable process for preparing of C6-C12-alkyl (meth)acrylic esters with a low acetate content.