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Method for separating and purifying fluorobenzene by extractive distillation

A separation, purification and extractive distillation technology is applied in the field of separation and purification of fluorobenzene in acidic fluorobenzene mixed solution, which can solve problems such as increasing consumption, and achieve the effects of reducing the amount of process wastewater and waste residue, improving product purity, and reducing environmental pollution.

Active Publication Date: 2020-03-31
YANCHENG INST OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the current anhydrous hydrogen fluoride diazonium pyrolysis (AHF) process for the production of fluorobenzene, the acidic fluorobenzene mixture (crude fluorobenzene) obtained in the synthesis process is washed with water, neutralized with liquid alkali, steam distillation and atmospheric pressure. The distillation process will additionally produce the rectification waste residue containing NaF and macromolecular aromatic hydrocarbon polymers and tar and other organic matter, and increase the technical problem of consumption. Method for separating and purifying fluorobenzene

Method used

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  • Method for separating and purifying fluorobenzene by extractive distillation
  • Method for separating and purifying fluorobenzene by extractive distillation
  • Method for separating and purifying fluorobenzene by extractive distillation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Add 150 mL of crude fluorobenzene organic phase mixture and 75 mL of dichloromethane ( That is, the ratio is 2.0), at 25 ° C, continuous stirring for 30 minutes. After standing still for 30 minutes, move the extract from the lower layer into a Webster fractionation column (height 60 cm, number of layers: 8), a condenser and a thermometer with an outer asbestos jacket, and adjust the temperature of the condenser and the thermal bath to control Reflux ratio to 1.2~1.4, carry out fractional distillation under normal pressure, and collect fractions at 40~42°C. When the reading of the thermometer in the fractionating column drops rapidly, continue to collect the distillate for about 2 to 5 minutes to obtain the dichloromethane recovery liquid. Continue to increase the temperature of the heating bath to 85°C. When it is detected that the content of fluorobenzene in the distillate gradually increases and the purity is higher than 99.5%, and the gas phase temperature rises ste...

Embodiment 2

[0031] The difference between this example and Example 1 is that the extraction ratio is 1.5, that is, take 150 mL of the crude fluorobenzene organic phase mixture, and 100 mL of dichloromethane, and keep the operating parameters of other processes unchanged, and collect dichloromethane and fluorine respectively. Benzene fraction.

[0032] The extraction yield of fluorobenzene is about 95%, the total yield is about 94%, the purity reaches 99.96%, the residual amount of extractant is 40ppm; the recovery rate of extractant is about 95%. The gas chromatography analysis result of gained fluorobenzene product is as follows image 3 shown.

Embodiment 3

[0034] The difference between this embodiment and Example 1 is that the ratio during extraction is 1.0, that is, 150 mL of crude fluorobenzene organic phase mixed solution and 150 mL of dichloromethane are taken, and the operating parameters of other processes are unchanged, and dichloromethane and dichloromethane are collected respectively. Fluorobenzene fraction.

[0035]The extraction yield of fluorobenzene is about 96%, the total yield is about 95%, the purity reaches 99.95%, the residual amount of extractant is 54ppm; the recovery rate of extractant is about 95%. The gas chromatography analysis result of gained fluorobenzene product is as follows Figure 4 shown.

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Abstract

The invention discloses a method for separating and purifying fluorobenzene by extractive distillation. The method comprises the following steps: selecting a liquid halogenated alkane as an extractingagent, optimizing extraction parameters, directly extracting and separating fluorobenzene from an acidic fluorobenzene mixed solution (crude fluorobenzene) synthesized by anhydrous hydrogen fluoridediazonium pyrolysis (AHF) process, carrying out primary rectification on an extracted solution under optimized rectification conditions to obtain a fluorobenzene product, and recycling the extractingagent at the same time. The process conditions are mild, the operation is simple, and no extra solid and liquid wastes are generated. Under the optimal conditions, the extraction rate of fluorobenzeneis greater than or equal to 95%, the total yield is greater than or equal to 90%, the purity can reach 99.9% at most, the residual quantity of the extracting agent is lower than 100 ppm, and the quality meets the requirements of industrial products; the average recovery rate of the extracting agent is greater than or equal to 93%, and the extracting agent can be recycled.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a method for separating and purifying fluorobenzene from an acidic fluorobenzene mixture synthesized by an existing anhydrous hydrogen fluoride diazonium pyrolysis (AHF) process by means of extraction and rectification. Background technique [0002] Fluorobenzene is a colorless liquid with a similar odor to benzene, with a boiling point of 84.73°C (760 mmHg) and a relative density of d 4 20 : 1.024, flash point -12.78°C, stable chemical properties, not decomposed even at 400°C, miscible with organic solvents such as ethanol, ether, acetone, benzene, etc., insoluble in water. Fluorobenzene is a basic aromatic organic fluorine intermediate. After unit reactions such as nitration, chlorination, bromination, alkylation, acylation, and reduction, it can synthesize a variety of new special effects medicines, pesticides, dyes, and fluorocarbon surfaces with excelle...

Claims

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Application Information

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IPC IPC(8): C07C17/386C07C25/13
CPCC07C17/386C07C25/13Y02P20/582
Inventor 陈景文曹淑红王玉琴陈浩邹松殷月媛
Owner YANCHENG INST OF TECH
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