Preparation method and equipment of 4-trifluoromethyl-nicotinic acid

A technology of trifluoromethylnicotinic acid and trifluoromethylnicotinic acid amide, which is applied in the field of 4-trifluoromethylnicotinic acid preparation, can solve the problems of high cost and achieve the effects of low cost, reduced reduction rate and increased yield

Inactive Publication Date: 2019-01-18
衢州凯沃化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] And 4-trifluoromethylnicotinic acid is an important intermediate of flonicamid, the most widely used is the synthesis of 4-trifluoromethylnicotin

Method used

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  • Preparation method and equipment of 4-trifluoromethyl-nicotinic acid

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Embodiment 1

[0022] A preparation method of 4-trifluoromethyl nicotinic acid, comprising the following steps:

[0023] 1. After mixing cyanoacetamide, ethyl trifluoroacetoacetate and KOH, reflux at 75°C for 6 hours, then filter, wash and dry to obtain 2,6-dihydroxy-3-cyano-4 - trifluoromethylpyridine;

[0024] 2. Dissolve 2,6-dihydroxy-3-cyano-4-trifluoromethylpyridine in dichloroethane, then add phosphorus oxychloride and mix, then add dropwise N,N dimethylformamide, in Reflux at 125°C for 6 hours, cool, add to ice-water mixture, stir and separate layers, extract the water layer with dichloroethane, combine organic layers, dry over anhydrous sodium sulfate, filter with suction, and obtain 2,6- Dichloro-3-cyano-4-trifluoromethylpyridine;

[0025] 3. Mix 2,6-dichloro-3-cyano-4-trifluoromethylpyridine with sodium bromide, then add 80% sulfuric acid dropwise to the solution, and obtain 2,6-dichloro- 4-trifluoromethylnicotinamide;

[0026] 4. Add 2,6-dichloro-4-trifluoromethylnicotinamide ...

Embodiment 2

[0030] In step 4, feed nitrogen before high-pressure hydrogenation, carry out N 2 Replace 3-4 times to avoid leaving air in the autoclave during hydrogenation.

Embodiment 3

[0032] A preparation method of 4-trifluoromethyl nicotinic acid, comprising the following steps:

[0033] 1. After mixing cyanoacetamide, ethyl trifluoroacetoacetate and KOH, reflux at 80°C for 10 hours, then filter, wash and dry to obtain 2,6-dihydroxy-3-cyano-4 - trifluoromethylpyridine;

[0034] 2. Dissolve 2,6-dihydroxy-3-cyano-4-trifluoromethylpyridine in dichloroethane, then add phosphorus oxychloride and mix, then add dropwise N,N dimethylformamide, in Reflux at 135°C for 10 h, cool, add to ice-water mixture, stir and separate layers, extract the water layer with dichloroethane, combine organic layers, dry over anhydrous sodium sulfate, filter with suction, and obtain 2,6- Dichloro-3-cyano-4-trifluoromethylpyridine;

[0035] 3. Mix 2,6-dichloro-3-cyano-4-trifluoromethylpyridine with sodium bromide, then add 80% sulfuric acid dropwise to the solution, and obtain 2,6-dichloro- 4-trifluoromethylnicotinamide;

[0036] 4. Add 2,6-dichloro-4-trifluoromethylnicotinamide in...

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Abstract

The invention discloses a preparation method of 4-trifluoromethyl-nicotinic acid. The preparation method comprises the following steps: taking cyanoacetamide, ethyl trifluoroacetoacetate and strong alkali as raw materials; firstly, preparing 2,6-dihydroxyl-3-cyano-4-tirfluoromethylpyridine; after carrying out chlorination through phosphorus oxychloride to obtain 2,6-dichloro-3-cyano-4-tirfluoromethylpyridine; then adding sulfuric acid to convert cyano into amino; and carrying out catalytic hydrogenation and hydrolysis to obtain the 4-trifluoromethyl-nicotinic acid. The preparation method has the advantages of high conversion rate and reduction of the cyano; the cyano is used as a strong electron suction group and has a carbon-nitrogen triple bond with relatively strong polarity; after thecyano is eliminated, the reduction rate can be remarkably reduced and the yield is improved; and the preparation method is worthy of being greatly popularized.

Description

technical field [0001] The invention relates to the technical field of preparation of 4-trifluoromethyl nicotinic acid, in particular to a preparation method of 4-trifluoromethyl nicotinic acid. Background technique [0002] Flunicamid is a new type of low-toxicity pyridine amide insect growth regulator insecticide. In 2007, it obtained the temporary registration certificate of pesticide products in my country. The preparation is 10% water-dispersible granules. [0003] In addition to its contact and stomach poisoning effects, flonicamid also has a good nerve agent and rapid antifeedant effect. Aphids and other piercing-sucking mouthparts will be quickly prevented from sucking the juice after inhaling the plant juice with flonicamid. There will be no excrement at all within 1 hour, and eventually they will die of starvation. [0004] There is no cross-resistance with other insecticides, and it has good neurotoxicity and rapid antifeedant activity against aphids, whiteflies,...

Claims

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Application Information

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IPC IPC(8): C07D213/80C07D213/803
CPCC07D213/80C07D213/803
Inventor 邱辉强
Owner 衢州凯沃化工有限公司
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