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Method for preparing 2-fluoro-4-hydroxyaniline

A technology of hydroxyaniline and o-fluoronitrobenzene is applied in the field of preparing 2-fluoro-4-hydroxyaniline by using a continuous flow microchannel reactor, and can solve the difficulties of 2-fluoro-4-hydroxyaniline, poor reaction selectivity, and poor reaction selectivity. Long time and other problems, to achieve the effect of easy process control, efficient response and strong continuity

Pending Publication Date: 2022-06-24
XIAN RUILIAN NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN101274898 provides a new process for producing 4-amino-3-fluorophenol, and provides the kettle-type preparation process and yield of 2-fluoro-4-hydroxyaniline. This method has fewer reaction steps and low cost. However, this reaction adopts a kettle-type one-pot method, and the reaction time is long, requiring more than 4 to 6 hours, resulting in the parallel generation of impurities in series, and part of the o-fluorophenyl hydroxylamine will continue to be reduced to o-fluoroaniline by-products, so the reaction selectivity is poor and the yield is low. ,high cost
[0004] This shows that above-mentioned two kinds of methods all have obvious technical defect at present, and industrialized production 2-fluoro-4-hydroxyaniline is more difficult

Method used

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  • Method for preparing 2-fluoro-4-hydroxyaniline
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  • Method for preparing 2-fluoro-4-hydroxyaniline

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Experimental program
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Embodiment 1

[0036] This embodiment provides a preferred method for preparing 2-fluoro-4-hydroxyaniline. The preparation process and the Corning microchannel reactor reaction process are shown in figure 1 and figure 2 .

[0037] Add 600g (4.25mol) o-fluoronitrobenzene to 2400g of 10% sulfuric acid solution, stir and dissolve; then add 2% platinum carbon 18g, stir, make platinum carbon completely dissolved in sulfuric acid solution, and o-fluoronitrobenzene The base benzene forms a homogeneous solution, that is, the material solution of the present invention.

[0038] The Corning microchannel reactor (consisting of 8 heart-shaped glass modules connected in series) was preheated to a reaction temperature of 60°C, and the configured material solution was injected into the Corning microchannel reactor through a feed pump, while passing through a gas flow meter. Precisely introduced hydrogen into the Corning microchannel reactor to ensure that the molar ratio of o-fluoronitrobenzene and hydr...

Embodiment 2

[0041] Embodiment 2: in the 10% hydrochloric acid solution of 2400g, add 600g (4.25mol) o-fluoronitrobenzene, stir and dissolve; then add 3% ruthenium carbon 24g, stir, make the ruthenium carbon be completely dissolved in the hydrochloric acid solution, It forms a homogeneous solution with o-fluoronitrobenzene, that is, the material solution of the present invention.

[0042] The Corning microchannel reactor (consisting of 6 heart-shaped glass modules connected in series) was preheated to a reaction temperature of 55°C, and the configured material solution was injected into the Corning microchannel reactor through a feed pump, while passing through a gas flow meter. Precisely introduced hydrogen into the Corning microchannel reactor to ensure that the molar ratio of o-fluoronitrobenzene and hydrogen was 1:3.5, the reaction pressure was set to 10bar, and the reaction time in the Corning microchannel reactor was 70s.

[0043] After the reaction, the reaction liquid flows out of ...

Embodiment 3

[0045] Embodiment 3: in the 8% phosphoric acid solution of 2400g, add 600g (4.25mol) o-fluoronitrobenzene, stir and dissolve; then add 3% palladium carbon 9g, stir, make palladium carbon be completely dissolved in 12% nitric acid In the solution, it forms a homogeneous solution with o-fluoronitrobenzene, that is, the material solution of the present invention.

[0046] The Corning microchannel reactor (consisting of 10 heart-shaped glass modules connected in series) was preheated to a reaction temperature of 50°C, and the configured material solution was injected into the Corning microchannel reactor through a feed pump, while passing through a gas flow meter. Precisely inject hydrogen into the Corning microchannel reactor, ensure that the molar ratio of o-fluoronitrobenzene and hydrogen is 1:4, set the reaction pressure to 10bar, and set the reaction time to 120s in the Corning microchannel reactor.

[0047] After the reaction, the reaction liquid flows out of the Corning mic...

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Abstract

The invention provides a method for preparing 2-fluoro-4-hydroxyaniline, which comprises the following steps of: performing catalytic hydrogenation on o-fluoronitrobenzene serving as a raw material in a continuous flow reactor to synthesize o-fluorophenylhydroxylamine, and rearranging under an acidic condition to obtain the 2-fluoro-4-hydroxyaniline. By adopting a continuous flow reaction technology, the technical defects of poor reaction selectivity, long reaction time, low reaction yield, high unit raw material cost, high safety risk and the like in the existing synthesis process of 2-fluoro-4-hydroxyaniline are systematically solved, and conditions are created for industrial production of 2-fluoro-4-hydroxyaniline.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, relates to a new process for preparing pharmaceutical intermediates, and in particular relates to a method for preparing 2-fluoro-4-hydroxyaniline by using a continuous flow microchannel reactor Background technique [0002] 2-Fluoro-4-hydroxyaniline is an important pharmaceutical intermediate. For example, it is a pharmaceutical intermediate for the treatment of liver cancer and bowel cancer, and it is also an intermediate for benzoylurea pesticides and insecticides. [0003] At present, there are two main methods for synthesizing 2-fluoro-4-hydroxyaniline. One is to use m-fluorophenol as a raw material, through nitration to generate 4-nitro-2-fluorophenol, and then reduction to obtain 2-fluoro-4-hydroxyaniline. Patent CN101302161 discloses a preparation method of 3-fluoro-4-nitrophenol, and describes in detail the nitration process of m-fluorophenol and the subsequent hydrogenation r...

Claims

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Application Information

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IPC IPC(8): C07C213/00C07C215/76C07C239/10
CPCC07C213/00C07C239/10C07C215/76
Inventor 段迎春张鸿宝张佳旭海啸高仁孝
Owner XIAN RUILIAN NEW MATERIAL CO LTD
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