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A kind of method for removing chlorosulfonic acid in the production of pentachlorobenzoyl chloride

A technology of pentachlorobenzoyl chloride and benzoyl chloride, applied in chemical instruments and methods, carboxylate preparation, organic chemistry, etc., can solve the problems of a large amount of washing wastewater, high labor intensity, and many operation steps, and achieve simple process , Good product quality, rapid increase in response speed

Active Publication Date: 2019-03-22
ZHEJIANG KANGFENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many operating steps in this process, a large amount of washing wastewater, waste gas during drying and acyl chlorination, high labor intensity, and high production costs.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A method for removing chlorosulfonic acid in the production of pentachlorobenzoyl chloride comprises the following steps:

[0021] (1), take benzoyl chloride as raw material, and chlorosulfonic acid is as solvent, and logical chlorine reaction generates pentachlorobenzoyl chloride;

[0022] (2), the chlorination reaction liquid that step (1) produces is put into vacuum recovery device and carries out vacuum recovery, and negative pressure vacuum degree is 0.07~0.098MPa, and temperature is 90~115 ℃;

[0023] (3) Because chlorosulfonic acid is easy to absorb moisture, in addition to residual chlorosulfonic acid, there is also a small amount of sulfuric acid in the recovered liquid after vacuum recovery. The recovered liquid enters the jacket water to cool down to 60-100 ° C, and the residual is detected by sampling Strong oxidizing acids content;

[0024] (4), add dry sodium chloride solid to the kettle under stirring, so that the molar ratio of sulfuric acid and sodium ...

Embodiment 2

[0029] Use benzoyl chloride and chlorosulfonic acid as raw materials to synthesize pentachlorobenzoyl chloride. Chlorosulfonic acid is first added into the chlorination kettle, then raw materials such as benzoyl chloride are added dropwise, and chlorine substitution reaction is carried out under stirring. Decline, when the chlorosulfonic acid basically does not distill, the precipitation recovery ends. The jacket is cooled with water, and the above-mentioned 280 grams of the solution is sampled, and the contents of chlorosulfonic acid and sulfuric acid are measured respectively. It contains 4.1 grams (0.042mol) of sulfuric acid and 7.8 grams (0.067mol) of chlorosulfonic acid. Under stirring, 5.4 grams of fine solid sodium chloride are added in multiple times, and the temperature of the feed is controlled at 70-75°C. Stir React for 0.2 hours, then add 5.5 grams of fine solid sodium bicarbonate several times under stirring, control the feeding temperature at 70-75°C, and stir f...

Embodiment 3

[0031] Use p-chlorobenzotrifluoride and chlorosulfonic acid as raw materials to synthesize pentachlorobenzotrifluoride. Chlorosulfonic acid is first added in the chlorination kettle, then raw materials such as p-chlorobenzotrifluoride are added dropwise, and chlorine substitution reaction is carried out under stirring. The temperature begins to drop, and when the chlorosulfonic acid does not distill off substantially, the precipitation recovery ends. The jacket was cooled with water, and the above-mentioned 320 grams of the solution was sampled, and the contents of chlorosulfonic acid and sulfuric acid were measured respectively. It contains 3.3 grams (0.034mol) of sulfuric acid, and 6.5 grams (0.056mol) of chlorosulfonic acid. Under stirring, 4.5 grams of fine solid sodium chloride are added in multiple times, and the temperature of the feed is controlled at 80-85 ° C. Stir React for 0.5 hours, then add 4.7 grams of fine solid sodium bicarbonate several times under stirring,...

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Abstract

A method of removing chlorosulfonic acid in pentachlorobenzoyl chloride production is disclosed. The method includes (1) feeding chlorine and reacting to produce pentachlorobenzoyl chloride by adopting benzoyl chloride as a raw material and chlorosulfonic acid as a solvent, (2) subjecting the chlorination solution generated in the step (1) to vacuum recovering, (3) cooling the recovered solution to 60-100 DEG C by jacket water cooling, sampling and detecting the content of residual high-oxidizability acids, (4) allowing the mole ratio of sulfuric acid in the recovered solution to sodium chloride to be 1:(2.10-2.5) and reacting the sulfuric acid and the sodium chloride to generate HCl and sodium sulfide, (5) allowing the mole ratio of the chlorosulfonic acid in the recovered solution to sodium bicarbonate to be 1:(0.9-1.0), and (6) allowing the mixture to stand, depositing, centralizing, and subjecting solid to filtration and washing with a solvent to further recover a product. The method has characteristics of cost saving, good product quality, a simple process, easy operation, low environment pollution, and the like.

Description

technical field [0001] The invention relates to chemical technology, specifically a method for removing chlorosulfonic acid in the production of pentachlorobenzoyl chloride. Background technique [0002] Pentachlorobenzoyl chloride is an important pharmaceutical and pesticide intermediate with broad market prospects. Benzoyl chloride is often used as raw material, chlorosulfonic acid is used as solvent, and pentachlorobenzoyl chloride is generated through chlorine reaction, and then chlorosulfonic acid is recovered at a certain temperature by vacuum, and the recovery temperature cannot be too high. Therefore, after recovery, there will still be a small amount of chlorosulfonic acid and concentrated sulfuric acid produced by the hydrolysis of chlorosulfonic acid in the recovered liquid. If ethanol and other solvents are directly used to dissolve the crystals, the solvent will decompose or even burn with chlorosulfonic acid and concentrated sulfuric acid. For this purpose, th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C51/62C07C51/64C07C63/70
CPCC07C51/62C07C51/64C07C63/70
Inventor 张位德杜广飞周浩天徐国群徐利伟
Owner ZHEJIANG KANGFENG CHEM
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