Method of two-column separation of benzoic acid, benzaldehyde and methylbenzene

A technology of benzaldehyde and benzoic acid, which is applied in the field of extracting toluene, benzaldehyde, and benzoic acid, can solve the problems of increasing energy consumption of the device, low purity, and affecting the quality of benzoic acid products, and achieves low energy consumption, simple operation, and long separation cycle short effect

Inactive Publication Date: 2015-10-14
SINOPEC YANGZI PETROCHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The traditional process only uses a rectification tower to extract benzoic acid. Benzaldehyde and toluene are used as raw materials to circulate into the oxidation reactor, which not only wastes a lot o...

Method used

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  • Method of two-column separation of benzoic acid, benzaldehyde and methylbenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The toluene oxidation reaction solution in this experiment is from Sinopec Shijiazhuang Refining and Chemical Company. The reaction solution is pumped into the first rectification tower (2) from the raw material tank (1) through the feed pump (3), and the feed temperature is 25°C. The number of trays in the first rectification column is 72, the toluene reaction liquid is fed in the 36th tray of the rectification column, the number of trays in the second rectification column (6) is 60, and the overhead distillate of the first rectification column After being condensed by the condenser (8), it enters the intermediate storage tank (4) and is fed to the 20th plate of the second rectification column. Add the reaction solution after the oxidation of toluene to the first rectification tower, and start heating when the liquid level reaches 1 / 3 of the tower tank; The temperature in the bottom of the distillation tower is controlled at 177°C, and the temperature at the top of the...

Embodiment 2

[0024] The toluene oxidation reaction solution in this experiment is from Sinopec Shijiazhuang Refining and Chemical Company. The reaction solution is pumped into the first rectification tower (2) from the raw material tank (1) through the feed pump (3), and the feed temperature is 25°C. The number of trays in the first rectification column is 74, the toluene reaction liquid is fed in the 33rd tray of the rectification column, the number of trays in the second rectification column (6) is 62, and the overhead distillate of the first rectification column After being condensed by the condenser (8), it enters the intermediate storage tank (4) and is fed to the 18th plate of the second rectification column. Add the reaction liquid after the oxidation of toluene to the first rectification tower, and start heating when the liquid level reaches 1 / 3 of the tower tank; The temperature in the bottom of the distillation tower is controlled at 175°C, and the temperature at the top of the t...

Embodiment 3

[0026] The toluene oxidation reaction solution in this experiment is from Sinopec Shijiazhuang Refining and Chemical Company. The reaction solution is pumped into the first rectification tower (2) from the raw material tank (1) through the feed pump (3), and the feed temperature is 25°C. The number of trays in the first rectification column is 75, the toluene reaction liquid is fed in the 30th tray of the rectification column, the number of trays in the second rectification column (6) is 65, and the overhead distillate of the first rectification column After being condensed by the condenser (8), it enters the intermediate storage tank (4) and is fed to the 15th plate of the second rectification column. Add the reaction liquid after the oxidation of toluene to the first rectification tower, and start heating when the liquid level reaches 1 / 3 of the tower tank; The temperature of the bottom of the distillation tower is controlled at 180°C, and the temperature at the top of the t...

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Abstract

The invention discloses a method of extracting benzoic acid, benzaldehyde and methylbenzene from a toluene oxidation reaction liquid and belongs to a separation method of the toluene oxidation reaction liquid. The method includes following steps: 1) feeding the toluene liquid-phase oxidation reaction liquid into the bottom of a first rectifying column, and heating the reaction liquid when the liquid level reaches 1/3-1/2 of the bottom of the first rectifying column; (2) when the apparatus reaches total reflux, feeding vapor for controlling the temperature of the bottom of the first rectifying column to be 250-260 DEG C and the temperature of the bottom of the first rectifying column to be 185 DEG C; (3) feeding the top discharged material from the first rectifying column into the middle-lower part of a second rectifying column, and controlling the temperature of the bottom of the second rectifying column to be 177-180 DEG C and the temperature of the bottom of the second rectifying column to be 110-112 DEG C; and (4) through a continuous middle material feeding method, withdrawing a material flow from the bottom of the first rectifying column to obtain the benzoic acid, withdrawing a top distilled substance from the top of the second rectifying column to obtain the methylbenzene, and withdrawing a material flow from the bottom of the second rectifying column to obtain the benzaldehyde. The method is short in separation period, is simple in operation, is low in energy consumption and is high in yield. The obtained benzoic acid is high in purity. The method can achieve industrialization of extraction of the benzoic acid, the benzaldehyde and the methylbenzene from the toluene oxidation reaction liquid.

Description

technical field [0001] The invention relates to a method for separating toluene oxidation reaction liquid, in particular to a method for extracting toluene, benzaldehyde and benzoic acid from toluene oxidation reaction liquid. Background technique [0002] After catalytic oxidation of toluene, about 13% (mass fraction, the same below) benzoic acid solution, about 5% benzaldehyde, about 82% toluene, benzyl alcohol, water and a small amount of acetophenone, biphenyl, methyl biphenyl, etc. Impurities. As the market application of benzaldehyde becomes more and more extensive, the utilization rate of benzaldehyde is getting higher and higher. Therefore, extracting about 5% benzaldehyde while extracting benzoic acid will increase the economic profit of the enterprise. The traditional process only uses a rectification tower to extract benzoic acid. Benzaldehyde and toluene are recycled into the oxidation reactor as raw materials, which not only wastes a lot of additional benzalde...

Claims

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Application Information

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IPC IPC(8): C07C63/06C07C51/44C07C47/54C07C45/82C07C15/06C07C7/04
Inventor 周永兵陈韶辉刘建新邢跃军杨爱武高洪伟肖翔
Owner SINOPEC YANGZI PETROCHEM
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