Continuous purification method for crude acetonitrile

A purification method and crude acetonitrile technology, applied in the direction of carboxylic acid nitrile purification/separation, organic chemistry, etc., can solve the problems of poor product purity and low energy utilization rate of the device, and achieve the effect of reducing operation burden, saving energy and ensuring purity

Active Publication Date: 2012-08-15
CHINA TIANCHEN ENG +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The problem to be solved by the present invention is to provide a continuous purification method for crude acetonitrile. Focusing on the problems of poor product purity and low device energy utilization rate exposed in the current domestic acetonitrile purification process, a set of practical process methods is proposed

Method used

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  • Continuous purification method for crude acetonitrile
  • Continuous purification method for crude acetonitrile

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Crude acetonitrile containing 50% acetonitrile, 45.95% water, 1.2% hydrocyanic acid, 2.4% acrylonitrile, 0.4% oxazole and 0.05% propionitrile is sent to the first rectification column.

[0044] The first rectification column adopts 23 theoretical plates, and crude acetonitrile enters the first rectification column from the fifth theoretical plate at first. The operating temperature at the top of the tower is 75°C, the operating temperature at the bottom of the tower is 100°C, the operating pressure at the top of the tower is 0.005MPa, the operating pressure at the bottom of the tower is 0.026MPa, and the reflux ratio is 13. The azeotrope of acetonitrile-water is extracted from the side line of the 15th theoretical plate, and sent to the acetonitrile reactor after condensation, and sodium hydroxide solution and formaldehyde are added at the same time to make the residual hydrocyanic acid and acrylonitrile in the azeotrope of acetonitrile-water After converting to high bo...

Embodiment 2

[0050] Crude acetonitrile containing 50% acetonitrile, 45.95% water, 1.2% hydrocyanic acid, 2.4% acrylonitrile, 0.4% oxazole and 0.05% propionitrile is sent to the first rectification column.

[0051] The first rectification column adopts 30 theoretical plates, and the crude acetonitrile enters the first rectification column from the 10th theoretical plate at first. The operating temperature at the top of the tower is 73°C, the operating temperature at the bottom of the tower is 97°C, the operating pressure at the top of the tower is 0.002MPa, the operating pressure at the bottom of the tower is 0.027MPa, and the reflux ratio is 20. The azeotrope of acetonitrile-water is extracted from the side line of the 20th theoretical plate, and sent to the acetonitrile reactor after condensation, and sodium hydroxide solution and formaldehyde are added at the same time to make the residual hydrocyanic acid and acrylonitrile in the azeotrope of acetonitrile-water After converting to high ...

Embodiment 3

[0057] Crude acetonitrile containing 50% acetonitrile, 45.95% water, 1.2% hydrocyanic acid, 2.4% acrylonitrile, 0.4% oxazole and 0.05% propionitrile is sent to the first rectification column.

[0058] The first rectification column adopts 40 theoretical plates, and the crude acetonitrile first enters the first rectification column from the sixth theoretical plate. The operating temperature at the top of the tower is 80°C, the operating temperature at the bottom of the tower is 104°C, the operating pressure at the top of the tower is 0.009MPa, the operating pressure at the bottom of the tower is 0.035MPa, and the reflux ratio is 12. The azeotrope of acetonitrile-water is extracted from the side line of the 25th theoretical plate, and sent to the acetonitrile reactor after condensation, and potassium hydroxide solution and formaldehyde are added at the same time to make the residual hydrocyanic acid and acrylonitrile in the azeotrope of acetonitrile-water After converting to hig...

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Abstract

The invention provides a continuous purification method for crude acetonitrile. A lateral line condenser is arranged at a third rectifying tower, so that the heat energy of an acetonitrile final product can be adequately recovered, the load of a reboiler at the bottom of the third rectifying tower and the refrigerant quantity of an acetonitrile final product cooler can be effectively reduced, the energy consumption can be saved, and 500-600MJ of energy can be saved for each ton of the acetonitrile product; and distillate is returned from the top of the third rectifying tower, so that the accumulation of oxazole in a system can be reduced, the yield of the acetonitrile can be guaranteed as well, and the problem that the operation load of a first rectifying tower can be obviously increased since all the distillate on the top of the third rectifying tower returns to the first rectifying tower in the prior art can be improved. Furthermore, a corresponding pipeline for adding a polymerization inhibitor is increased on the conventional three-tower and one-kettle refining technology, so that the problem that the exposed devices are easy to polymerize in the existing acetonitrile purification process in China can be solved, and the continuous purification method has the advantages of being high in industrial application value, and high in acetonitrile final product purity.

Description

technical field [0001] The invention relates to a continuous purification method of crude acetonitrile. Background technique [0002] Acetonitrile is an organic solvent with excellent properties and an important raw material for fine chemicals. It is used as an extractant to extract butadiene and isoprene from olefins and paraffins in petrochemical industry. It is an important synthetic raw material for organic synthesis, medicine, pesticides, surfactants, dyes and other fine chemicals. It is also used as a chromatographic The mobile phase solvent for analysis has been used as a DNA synthesis / purification solvent, a solvent for organic EL material synthesis, and a cleaning solvent for electronic components in recent years. These applications all have high requirements for the purity of acetonitrile. [0003] The methods for industrial production of acetonitrile include direct synthesis (such as the reaction of acetic acid or propane or ethanol with ammonia) and indirect met...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/03C07C253/34
Inventor 杨克俭袁学民赵文文马国栋李强李荣郑仁王美娇史骞姚立东王瑞博
Owner CHINA TIANCHEN ENG
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