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Preparation method of 3-chloro-4-fluoroaniline

A technology of fluoroaniline and fluoronitrobenzene, which is applied in the field of preparation of 3-chloro-4-fluoroaniline, can solve the problems of cumbersome operation, serious pollution, increased cost, etc., and achieve simple and reasonable process, high yield and selectivity Effect

Inactive Publication Date: 2015-01-21
DO FLUORIDE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The reaction uses iron powder to catalyze reduction. Although the process is relatively mature, the reaction will produce a large amount of acid mist and iron sludge containing phenylcyclamine, causing serious pollution.
[0004] At present, the preparation of halogenated anilines by catalytic hydrogenation is relatively common, but solvents such as aliphatic alcohols, aromatic hydrocarbons, tetrahydrofuran, etc. are often used to participate in the reaction. After the reaction, distillation or rectification is required to separate the products, and the operation is relatively cumbersome.
For example, if Raney nickel is used to catalyze the hydrogenation reaction, it is necessary to introduce H in the methanol medium first. 2 Reduction and replacement, the reaction temperature is low, there are few by-products, and the post-treatment is simple, which can effectively eliminate the pollution of the three wastes, but the reaction needs to use a solvent, and the solvent recovery will increase the cost

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The preparation method of 3-chloro-4-fluoroaniline in this example comprises the following steps: 600 g of 3-chloro-4-fluoronitrobenzene, 1% Pt / C (purchased from Kangna New Materials (Hangzhou) Co., Ltd. ) 2g into the reaction kettle, replace the gas in the kettle with high-purity nitrogen three times, then replace the gas in the kettle with hydrogen three times, pass in hydrogen to keep the pressure at 0.5MPa, raise the temperature to 60°C, start stirring, react for 8 hours, and the reaction is over Finally, the crude product was filtered while it was hot, and the crude product was rectified. First, the temperature was raised to 100°C under normal pressure, and the former component was distilled off, and then the vacuum was gradually turned on. The fraction was collected and tested with the temperature rising, and the purity was 99.5%. 467.5 g of 3-chloro-4-fluoroaniline, yield 94%.

Embodiment 2

[0017] The preparation method of 3-chloro-4-fluoroaniline in this example comprises the following steps: 60 kg of 3-chloro-4-fluoronitrobenzene, 1% Pt / C (purchased from Kangna New Materials (Hangzhou) Co., Ltd. ) 200g into the reaction kettle, replace the gas in the kettle with high-purity nitrogen three times, then replace the gas in the kettle with hydrogen three times, pass in hydrogen to keep the pressure at 0.8MPa, raise the temperature to 80°C, start stirring, react for 5 hours, and the reaction is over Finally, the crude product was filtered while it was hot, and the crude product was rectified. First, the temperature was raised to 100°C under normal pressure to distill off the former components, and then the vacuum was gradually turned on. The fractions were collected and tested as the temperature rose, and the purity was 99.6%. 47.8kg of 3-chloro-4-fluoroaniline, yield 96%.

Embodiment 3

[0019] The preparation method of 3-chloro-4-fluoroaniline in this example comprises the following steps: 60 kg of 3-chloro-4-fluoronitrobenzene, 1% Pt / C (purchased from Kangna New Materials (Hangzhou) Co., Ltd. ) 150g into the reaction kettle, replace the gas in the kettle with high-purity nitrogen three times, then replace the gas in the kettle with hydrogen three times, pass in hydrogen to keep the pressure at 5.0MPa, heat up to 50°C, start stirring, react for 10 hours, and the reaction is over Finally, the crude product was filtered while it was hot, and the crude product was rectified. First, the temperature was raised to 100°C under normal pressure to distill off the former components, and then the vacuum was gradually turned on. The fractions were collected and tested as the temperature rose, and the purity was 99.7%. The 3-chloro-4-fluoroaniline, yield 94%.

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Abstract

The invention discloses a preparation method of 3-chloro-4-fluoroaniline, and belongs to the technical field of organic chemical industry. The preparation method comprises the following steps of weighing 3-chloro-4-fluoronitrobenzene and 1% Pt / C catalyst and reacting for 1-10 hours at a temperature of 50-100 DEG C and in a hydrogen atmosphere of 0.1-5 MPa, wherein a mass ratio of 3-chloro-4-fluoronitrobenzene to 1% Pt / C catalyst is (200-400):1. The preparation method takes 3-chloro-4-fluoronitrobenzene as a raw material and prepares 3-chloro-4-fluoroaniline by a hydrogenation substitution reaction under catalysis of 1% Pt / C catalyst, has high reaction conversion rate, high yield and high selectivity, adopts no organic solvent, is simple and reasonable in process, and is suitable for large-scale production. The purity of 3-chloro-4-fluoroaniline prepared by the method can reach over 99.5%; and the yield reaches over 94%.

Description

technical field [0001] The invention specifically relates to a preparation method of 3-chloro-4-fluoroaniline, which belongs to the technical field of organic chemical industry. Background technique [0002] 3-Chloro-4-fluoroaniline (FCA) is the main synthetic raw material intermediate of new-type, high-efficiency, and broad-spectrum antibacterial drugs newly developed in recent years - norfloxacin, ofloxacin, ciprofloxacin, and norfloxacin. It is also an important raw material for fluorine-containing herbicides and insecticides, and is widely used in medicine, pesticides, dyes and other fields. With the rise of the field and the popularization of drugs, the demand for 3-chloro-4-fluoroaniline is increasing day by day. Therefore, its synthetic method is widely concerned by people. [0003] There are many ways to synthesize 3-chloro-4-fluoroaniline, the most important of which is to use 3-chloro-4-fluoronitrobenzene to prepare 3-chloro-4-fluoroaniline through reduction reac...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/36
Inventor 侯红军杨华春薛旭金司腾飞杨明霞师玉萍邹英武贺志荣姚超
Owner DO FLUORIDE CHEM CO LTD
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