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Preparation method of hexafluorobenzene

A technology of hexafluorobenzene and potassium fluoride, which is applied in the field of preparation of hexafluorobenzene, can solve the problems of low conversion rate of reaction substrate, complex product composition, difficult post-processing, etc., and achieves easy separation and recovery, simple reaction steps, and solvent The effect of less amount of denaturation

Inactive Publication Date: 2018-03-23
DALIAN QIKAI MEDICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This will seriously affect the yield of the reaction and increase the difficulty of post-processing. Considering the reaction process and atom utilization, the cost is very high
The method of producing hexafluorobenzene by high-temperature cracking of fluorohaloalkane is simple, fast, and convenient for continuous production, but the complexity of free radical reactions makes the composition of the product more complicated, which brings difficulties to post-processing, and the conversion of the reaction substrate The rate is lower, so the production efficiency is also lower

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Add 134g of potassium fluoride, 350ml of benzonitrile and 300ml of toluene in sequence into a 1000ml four-necked flask equipped with a water separator. Heat to reflux at 120-130°C under mechanical stirring, separate water, turn on the water separator switch and heat to 185°C to remove toluene after no water is separated. After no toluene was evaporated, the temperature was lowered to room temperature under nitrogen protection and transferred to a 1000ml autoclave, and 314g of chloropentafluorobenzene, 17g of tetraphenylphosphonium bromide and 5g of nitrobenzene were added, and the temperature was raised to 250°C for 35 hours. After the reaction is finished, the reaction system is distilled under normal pressure and the fraction at 40-160° C. is received. A 30cm packed rectification column is used to carry out atmospheric rectification on the above receiver, and simultaneously receive the fraction at 79-81°C to obtain the final product with a purity of more than 99%, wit...

Embodiment 2

[0027] Add 134g of potassium fluoride, 350ml of sulfolane and 300ml of toluene in sequence into a 1000ml four-necked flask equipped with a water separator. Heat to reflux at 120-130°C under mechanical stirring, separate water, turn on the water separator switch and heat to 185°C to remove toluene after no water is separated. After no toluene is evaporated, nitrogen protection is used to cool down to room temperature and transfer to a 1000ml autoclave, and add 314g chloropentafluorobenzene, 15g tetrakis(diethylamino)phosphonium bromide and 5g nitrobenzene, and heat up to 240°C for 30 hours . After the reaction is finished, the reaction system is distilled under normal pressure and the fraction at 40-160° C. is received. A 30cm packed rectification column is used to carry out atmospheric rectification on the above receiver, and simultaneously receive the fraction at 79-81°C to obtain a final product with a purity of more than 99%, with a yield of 71.7%.

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Abstract

The invention relates to a preparation method of hexafluorobenzene, and belongs to the field of chemical production techniques. The preparation method of the hexafluorobenzene is characterized by comprising the following technologies: (1) mixing potassium fluoride with a nonprotic polar solvent, thus obtaining a mixed solution; (2) adding a reaction substrate, nitrobenzene and a phase transfer catalyst in the mixed solution, thus obtaining a reaction system, wherein the reaction substrate is chloropentafluorobenzene; (3) putting the reaction system obtained in the step (2) in a high-pressure kettle, sealing after discharging air in the high-pressure kettle, and reacting, thus obtaining a product; (4) rectifying the product after distilling, thus obtaining the hexafluorobenzene. According to the method disclosed by the invention, the energy consumption is lower, side effects are few, the reaction steps are simple, and the operation is easy; the solvent denaturation amount is less, separation and recycling are easy, and compared with other methods, and the method is greener and more environmental friendly.

Description

technical field [0001] The invention relates to a preparation method of hexafluorobenzene, which belongs to the field of chemical production technology. Background technique [0002] Hexafluorobenzene, also known as perfluorobenzene, is often used as an excellent solvent for anesthetics and various organic substances. It is also an important intermediate for the synthesis of perfluorinated aromatic compounds. It has broad application prospects in chemical, pharmaceutical and liquid crystal materials. [0003] So far, there are mainly two synthesis methods of hexafluorobenzene, namely direct fluorination of aromatic halogenated compounds and pyrolysis of fluorohaloalkanes. However, since the reaction substrate of the direct fluorination method does not have a strong charge-absorbing group, it is unfavorable for the halogen exchange reaction to occur. Therefore, this method usually requires a very high temperature to carry out, and the reaction rate is very slow. Prolonged hi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C17/20C07C17/383C07C25/13
CPCC07C17/208C07C17/383C07C25/13
Inventor 田瀚卿姜殿平张洪学
Owner DALIAN QIKAI MEDICAL TECH
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