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Method for treating acetic acid and water containing dialkylaromatics by azeotropic distillation

A technology of dialkylaromatics and azeotropic distillation, which is applied in chemical instruments and methods, preparation of carboxylate, preparation of organic compounds, etc., can solve the problems of difficult operation, increased investment cost, increased condenser and online analysis Instrument and other problems, to achieve the effect of simple operation, low cost, and reduce the content of organic matter

Active Publication Date: 2016-10-05
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since this area belongs to the stage where the composition of vapor and liquid changes most obviously in the actual production process, intermittent or batch operation will lead to small changes in the amount of internal steam and liquid materials, which will break the concentration balance established in the production process, and eventually It affects the separation effect, so it is not suitable for continuous rectification production. At the same time, due to the addition of condensers and online analysis instruments, the investment cost is increased, and the operation is also very difficult.

Method used

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  • Method for treating acetic acid and water containing dialkylaromatics by azeotropic distillation
  • Method for treating acetic acid and water containing dialkylaromatics by azeotropic distillation
  • Method for treating acetic acid and water containing dialkylaromatics by azeotropic distillation

Examples

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Effect test

Embodiment 1

[0037] A feed stream 1 of acetic acid and water containing p-xylene enters the azeotropic distillation column A from the 14th tray at a flow rate of 5075.71kg / h, and the concentration of acetic acid in the feed stream 1 is 54.6wt% , the p-xylene flow rate is 13.6kg / h, and the azeotropic distillation column is 45 trays. Simultaneously, a stream 6 is continuously drawn out at the position side of the 10th plate of the lower limit of the p-xylene enrichment (azeotropic region) of the azeotropic rectification tower, and its extraction amount is close to the flow rate of p-xylene in the feed stream 1, That is 15.92kg / h. according to figure 2 It can be seen from the temperature distribution that the temperature here is about 96.3°C, and the corresponding components in stream 6 are p-xylene concentration of 47.5wt%, sec-butyl acetate concentration of 19.1wt%, water concentration of 19.6wt%, acetic acid Concentration 12wt% and methyl acetate 1.8wt%. In the present invention, the s...

Embodiment 2

[0040] A feed stream 1 of acetic acid and water containing p-xylene enters the azeotropic distillation column A from the 22nd tray at a flow rate of 5075.71kg / h, and the concentration of acetic acid in the feed stream 1 is 74.6wt% , the p-xylene flow rate is 13.6kg / h, and the azeotropic distillation column is 45 trays. Simultaneously, a stream 6 is continuously drawn out at the side of the 18th plate plate position of the lower limit of the p-xylene enrichment (azeotropic region) of the azeotropic rectification tower, and its extraction amount is close to the flow rate of p-xylene in the feed stream 1, That is 14.62kg / h. according to figure 2 It can be seen from the temperature distribution that the temperature here is about 98.6°C, and the corresponding components in stream 6 are the concentration of p-xylene 40.5wt%, the concentration of sec-butyl acetate 23.1wt%, the concentration of water 21.6wt%, and the concentration of acetic acid 12.5wt% and methyl acetate 2.3wt%. ...

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Abstract

In the process of preparing aromatic carboxylic acids, the present invention can continuously extract unreacted dialkyl aromatics in the azeotropic distillation tower for recycling, and will not break the concentration established in the production process to affect the separation effect, and can realize continuous operation . The method of the present invention is simple to operate and low in cost, and the unreacted dialkyl aromatics will no longer interfere with the rectification characteristics of the azeotropic rectification tower and the composition of the system, so that the dehydration composition of acetic acid as the rectification target can be Maintain stability, thereby reducing the content of organic matter in the overhead distillate water.

Description

technical field [0001] The present invention relates to a method for the recovery of acetic acid and water containing dialkylaromatics by azeotropic distillation in the production of aromatic carboxylic acids, especially in the production of terephthalic acid when the feed contains p-xylene , A process for purifying acetic acid and water by azeotropic distillation. Background technique [0002] The traditional production process of aromatic carboxylic acids is usually obtained by liquid-phase air oxidation of alkylaromatics under pressure. The liquid-phase oxidation of alkylaromatics is the gradual oxidation of the alkyl groups on aromatics to aldehydes and carboxylic acids in the presence of acetic acid solvent and a metal catalyst system, and finally to aromatic carboxylic acids. [0003] The oxidation process of alkylaromatics will generate water, accompanied by a large amount of heat. In order to keep the temperature of the reaction process and the water content in the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/26C07C63/24C07C51/265C07C53/08C07C51/46
Inventor 刘建新肖翔孟海钱学勤邢跃军朱伟周永兵
Owner SINOPEC YANGZI PETROCHEM