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Separation method of o-chlorobenzoic acid and p-chlorobenzoic acid mixture

A technology of o-chlorobenzoic acid and p-chlorobenzoic acid, applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., can solve the problems of recovery of hydrotropes and high separation costs, and achieve mild separation conditions and low energy consumption Effect

Active Publication Date: 2008-02-20
南京资环工程技术研究院有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The problem with this method is that it is difficult to recover the hydrotrope from its complex with o-chlorobenzoic acid and p-chlorobenzoic acid, resulting in high separation costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] 60g of the mixture of o-chlorobenzoic acid and p-chlorobenzoic acid, the ratio of o-chlorobenzoic acid is 55 / 45, disperse it with 800g of water, stir, heat to 30°C, add 1160mL of potassium hydroxide solution with a molar concentration of 0.2mol / L (the amount is expressed in moles number is calculated as 1.1 times of the number of moles of o-chlorobenzoic acid), and the maintenance temperature is 30° C. After 5 hours of reaction, the stirring is stopped, filtered while hot, and the filter cake is vacuum-dried at 80° C. to obtain 23.7 g of p-chlorobenzoic acid. According to liquid chromatography analysis, the mass content is 99.12%. Filtrate is heated to 30 ℃ again, and adding mass concentration is 36% hydrochloric acid 2.6g (consumption is calculated as 1.2 times of the molar number of potassium p-chlorobenzoate in the filtrate in moles), reacted for 5 hours, filtered the crystals separated out, filter cake It is a mixture of o-chlorobenzoic acid and p-chlorobenzoic acid...

Embodiment 2

[0018] 60g of the mixture of o-chlorobenzoic acid and p-chlorobenzoic acid, the ratio of ortho-chlorobenzoic acid is 55 / 45, disperse it with 900g of water, stir, heat to 55°C, add 27mL of sodium hydroxide solution with a molar concentration of 10mol / L (the dosage is o-chloro 1.3 times of the molar number of benzoic acid), the maintenance temperature is 55 DEG C, stop stirring after reacting for 4 hours, filter while hot, filter cake obtains p-chlorobenzoic acid 17.1g at 80 DEG C in vacuum, through high performance liquid chromatography analysis, The mass content is 99.55%. Filtrate is heated to 55 ℃ again, and adding mass concentration is 36% hydrochloric acid 12.8g (consumption is calculated as 2.0 times of the molar number of sodium p-chlorobenzoate in filtrate in molar number), reacted 4 hours, filtered the crystal that separates out, and filter cake is The mixture of o-chlorobenzoic acid and p-chlorobenzoic acid is used for the next separation after being mixed with raw ma...

Embodiment 3

[0020] 60g of a mixture of o-chlorobenzoic acid and p-chlorobenzoic acid, the ratio of o-chlorobenzoic acid to 55 / 45, was dispersed with 1000g of water, stirred, heated to 60°C, and 506mL of potassium hydroxide solution with a molar concentration of 0.5mol / L was added (the amount is expressed in moles number is calculated as 1.2 times of the number of moles of o-chlorobenzoic acid), the maintenance temperature is 60° C., and the stirring is stopped after 3 hours of reaction, filtered while hot, and the filter cake is vacuum-dried at 80° C. to obtain 20.4 g of p-chlorobenzoic acid. According to liquid chromatography analysis, the mass content is 99.43%. The filtrate was heated to 60°C again, and 3.3 g of anhydrous acetic acid was added (the amount in moles was calculated as 1.2 times the molar number of sodium p-chlorobenzoate in the filtrate), reacted for 3 hours, filtered the separated crystals, and the filter cake was o-chlorobenzoic acid Mixed with p-chlorobenzoic acid, mix...

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PUM

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Abstract

A process for separating o-chlorobenzoic acid and p-chlorobenzoic acid from their mixture includes such steps as dispersing said mixture in water, stirring while heating, adding alkaline extractant, reaction, filter, drying the filtered cake to obtain p-chlorobenzoic acid, stirring the filtrate while heating, adding acidic extractant, reaction, filter, adding the acidic extractant to the filtrate until pH=1.0, filter, and drying the filtered cake to obtain o-chlorobenzoic acid.

Description

technical field [0001] The invention relates to a method for separating two compounds, in particular, a method for separating o-chlorobenzoic acid and p-chlorobenzoic acid from a mixture of o-chlorobenzoic acid and p-chlorobenzoic acid. Background technique [0002] O-chlorobenzoic acid and p-chlorobenzoic acid are important organic synthesis intermediates and analytical reagents in the fields of dyes, pesticides, and medicine. Among them, o-chlorobenzoic acid can be used to prepare drugs such as chlorpromazine, anti-inflammatory spirit, mebendazole, diclofenac, and clotrimazole; it is also a standard reagent for alkali and iodometric methods; in addition, it can also be used as an antiseptic for adhesives and paints Agents, synthetic dyes and color films, etc. p-Chlorobenzoic acid can be used to synthesize broad-spectrum anthelmintic mebendazole, flubendazole, non-steroidal anti-inflammatory analgesic drugs and analytical reagents. [0003] The existing production of o-ch...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C63/70C07C51/42
Inventor 乔旭汤吉海崔咪芬
Owner 南京资环工程技术研究院有限公司
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