Method for recovering high-purity octafluorocyclobutane from difluoromonochloro methane cracking residual liquid

A technology for difluoromonochloromethane and octafluorocyclobutane is applied in the field of recovering high-purity octafluorocyclobutane, can solve problems such as inability to guarantee, and achieve the effects of easy operation, increased relative volatility, and no loss

Active Publication Date: 2015-04-22
SHANDONG DONGYUE POLYMER MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the purity of the octafluorocyclobutane separated by this method can only be guaranteed to be above 99%, and the content of hydrogen-containing and chlorine-containing impurities cannot be guaranteed to be lower than 10ppm

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] A method for recovering high-purity octafluorocyclobutane from difluorochloromethane pyrolysis raffinate, comprising the following steps:

[0034] (1) Difluorochloromethane pyrolysis raffinate is rectified to obtain octafluorocyclobutane and its azeotrope;

[0035] According to the method provided by the Chinese patent document CN101134710A, the difluorochloromethane pyrolysis raffinate is passed through a rectification tower, and the pressure at the top of the rectification tower is controlled to be 0.8Mpa to remove components with a boiling point greater than 20°C; The components are rectified through the light removal tower, and the pressure at the top of the light removal tower is controlled to 0.6MPa, and the components with a boiling point lower than -10°C are removed; The pressure at the top of the tower is 0.4MPa, and octafluorocyclobutane and its azeotrope are obtained at the top of the tower;

[0036] (2) Octafluorocyclobutane and its azeotrope obtained by st...

Embodiment 2

[0041] A method for recovering high-purity octafluorocyclobutane from difluorochloromethane pyrolysis raffinate, comprising the following steps:

[0042] (1) Difluorochloromethane pyrolysis raffinate is rectified to obtain octafluorocyclobutane and its azeotrope;

[0043] Concrete operation is with embodiment 1;

[0044] (2) Octafluorocyclobutane and its azeotrope obtained by step (1) enter the extractive distillation column for extraction and rectification, specifically:

[0045] The theoretical plate number of the extractive distillation tower is 95, the operating pressure is 0.2MPa, the top temperature of the extractive distillation tower is 24-25°C, and the temperature of the bottom of the tower is 35-40°C;

[0046]Feed from 25 theoretical plates of the extractive distillation tower at a rate of 100kg / h, and the extractant is fed from the 10th theoretical plate of the extractive distillation tower. The amount of the extractant added is the same as that of octafluorocyclob...

Embodiment 3

[0049] A method for recovering high-purity octafluorocyclobutane from difluorochloromethane pyrolysis raffinate, comprising the following steps:

[0050] (1) Difluorochloromethane pyrolysis raffinate is rectified to obtain octafluorocyclobutane and its azeotrope;

[0051] Concrete operation is with embodiment 1;

[0052] (2) Octafluorocyclobutane and its azeotrope obtained by step (1) enter the extractive distillation column for extraction and rectification, specifically:

[0053] The number of theoretical plates of the extractive distillation tower is 95, the operating pressure is 0.3MPa, the temperature of the top of the extractive distillation tower is 33-34°C, and the temperature of the bottom of the tower is 45-50°C;

[0054] Feed from 25 theoretical plates of the extractive distillation tower at a rate of 100kg / h, and the extractant is fed from the 10th theoretical plate of the extractive distillation tower. The amount of the extractant added is the same as that of octa...

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Abstract

The invention relates to a method for recovering high-purity octafluorocyclobutane from difluoromonochloro methane cracking residual liquid. The method comprises the following steps: (1) difluoromonochloro methane cracking residual liquid is rectified, such that octafluorocyclobutane and azeotrope thereof are obtained; and (2) the octafluorocyclobutane and azeotrope thereof obtained in the step (1) are subjected to extractive distillation in an extractive distillation tower; octafluorocyclobutane is obtained from the top of the extractive distillation tower, and a mixed component of an extraction agent and impurities is obtained from the bottom of the extractive distillation tower; the mixed component is desorbed in an extractive desorption tower, and the obtained extraction agent is recycled and reused in the extractive distillation tower. According to the invention, a composite solvent composed of ionic liquid and organic solution is adopted as the extraction agent, such that the relative volatility of octafluorocyclobutane and azeotrope thereof can be substantially increased, and system high-efficiency separation is realized. With the method, octafluorocyclobutane purity is up to 99.999%.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for recovering high-purity octafluorocyclobutane from the raffinate produced by the high-boiling raffinate produced by the cracking of difluorochloromethane in the production process of tetrafluoroethylene. Background technique [0002] At present, the common tetrafluoroethylene production process in the fluorine chemical industry is the pyrolysis process of difluorochloromethane. Due to the principle, a part of octafluorocyclobutane will inevitably be produced in the process. In the technological process, a variety of high-boiling by-products produced during the cracking process are often discharged into the incineration system as a raffinate for treatment, and octafluorocyclobutane accounts for a large part. [0003] Octafluorocyclobutane can be used as a raw material for pyrolysis to prepare hexafluoropropylene, and can also be used as a plasma e...

Claims

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Application Information

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IPC IPC(8): C07C23/06C07C17/386
CPCY02P20/54
Inventor 陈越夏俊王长国
Owner SHANDONG DONGYUE POLYMER MATERIAL
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