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Method for purifying perflurooctanoic acid

A technology of perfluorooctanoic acid and aluminum sulfate, which is used in the separation/purification of carboxylic acid compounds, organic chemistry, etc., and can solve the problems of surface activity, pollution of derivative products, isomerization, etc.

Inactive Publication Date: 2013-11-06
上海富诺林精细化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] As we all know, the electrolysis reaction process of organic compounds is often very complicated, so the composition of electrolysis products is also very complicated.
[0009] In the above electrolysis process, side reactions such as chain scission, cyclization, isomerization, coke formation, and oligomerization occurred, and the free fluorine impurities generated during the electrolysis process were converted into highly corrosive fluorine impurities under acidic conditions. HF, which also affects its surface activity and may contaminate derivative products made using PFOA
[0010] At present, most enterprises that produce PFOA usually use rectification to separate PFOA from the reaction mixture, but it is found that it is difficult to separate the product PFOA from free fluorine impurities with the existing rectification method, resulting in a high content of free fluorine in the product. In terms of the appearance of the product, when the package of the product that has been placed for several months is opened, a small amount of white smoke can be found escaping, accompanied by a strong pungent smell. When the free fluorine content is measured by colorimetry, the result is often high at 500ppm
[0011] The content of free fluorine components in PFOA products will have an important impact on the surface activity of PFOA products, and may cause pollution to its derivative products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Before rectification, add 100 grams of 1.5% aluminum sulfate solution to 133 grams of crude product of perfluorooctanoic acid with a purity of 75%, heat to 70°C, keep for 4.5 hours, add 10 grams of glass beads with a particle size of 0.1mm, and rectify to obtain Add excess barium chloride to PFOA products to remove sulfate radicals, centrifuge to obtain a clear solution, add zirconium oxychloride hydrochloric acid aqueous solution, add xylenol orange, heat, cool and measure the absorption rate at the wavelength λ=546nm, and draw the standard at the same time Curve, and as a blank sample, the measurement results are shown in Table 1.

Embodiment 2

[0045]Before rectification, add 100 grams of 2.0% aluminum sulfate solution to 133 grams of crude product of perfluorooctanoic acid with a purity of 75%, heat to 70°C, keep for 4.5 hours, add 10 grams of glass beads with a particle diameter of 0.1mm, and rectify to obtain Add excess barium chloride to PFOA products to remove sulfate radicals, centrifuge to obtain a clear solution, add zirconium oxychloride hydrochloric acid aqueous solution, add xylenol orange, heat, cool and measure the absorption rate at the wavelength λ=546nm, and draw the standard at the same time Curve, and as a blank sample, the measurement results are shown in Table 1.

Embodiment 3

[0047] Before rectification, add 100 grams of 5.0% aluminum sulfate solution to 133 grams of crude product of perfluorooctanoic acid with a purity of 75%, heat to 70°C, keep for 4.5 hours, add 10 grams of glass beads with a particle size of 0.1mm, and rectify to obtain Add excess barium chloride to PFOA products to remove sulfate radicals, centrifuge to obtain a clear solution, add zirconium oxychloride hydrochloric acid aqueous solution, add xylenol orange, heat, cool and measure the absorption rate at the wavelength λ=546nm, and draw the standard at the same time Curve, and as a blank sample, the measurement results are shown in Table 1.

[0048] Table 1

[0049]

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PUM

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Abstract

The invention discloses a fractional distillation method of perfluorooctanoic acid, which comprises the following steps: 1) mother liquor of reaction mixtures containing the perfluorooctanoic acid, hydrogen fluoride and free fluorine is provided; 2) aluminum sulfate solution is added in the mother liquor of the reaction mixtures to form mixed liquid containing the aluminum sulfate, the weight ratio of the weight of the perfluorooctanoic acid to the weight of the added aluminum sulfate is 100: 1 to 5:1 counted by a pure perfluorooctanoic acid product; 3) the mixed liquid containing the aluminum sulfate is heated for 1 to 10 hours at the temperature of 25 to 100 DEG C; 4) glass beads with the particle size of 0.06 to 0.16mm are added in the heated mixed liquid containing the aluminum sulfate, the weight ratio of the weight of the perfluorooctanoic acid to the weight of the added glass beads is 50:1 to 1:1 counted by the pure perfluorooctanoic acid product; and 5) the fractional distillation is carried out.

Description

technical field [0001] The invention relates to a method for purifying perfluorooctanoic acid. Background technique [0002] Perfluorooctanoic acid is a highly efficient surfactant. Its derivatives have been widely used in the surface finishing of textiles, paper and leather to achieve waterproof, oil-proof and decontamination effects. The solution prepared by perfluorooctanoic acid derivatives can also It can be used as a high-efficiency fire extinguishing agent, especially ammonium perfluorooctanoate is also used in the synthesis of fluorine-containing polymer polytetrafluoroethylene and fluororubber, etc., and has important application value in industry. [0003] At present, the production of perfluorooctanoic acid in the world mostly adopts electrolysis and telomerization. The electrolysis method is to add anhydrous hydrogen fluoride and octanoyl chloride to the Simons electrolytic cell, and electrolyze under the condition of low voltage and high current to generate perf...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C53/21C07C51/44
Inventor 周焕钧周维勇
Owner 上海富诺林精细化工有限公司