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Preparation of 2,3,4,5,6-pentafluorobenzyl alcohol

A technology of pentafluorobenzyl alcohol and pentafluorobenzonitrile is applied in 2 fields, can solve the problems of high price, corrosion of production equipment, low temperature, etc., and achieves the effects of low cost of raw materials, reduced pollution and simple operation

Inactive Publication Date: 2009-04-22
ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the use of thionyl chloride for acid chlorination in the reaction process, it caused great corrosion to the production equipment and serious environmental pollution, and in the subsequent hydrogenation process, expensive lithium tri-tert-butoxy aluminum hydride was used, and the used The temperature is low and the conditions are relatively harsh, so the whole process is not easy for industrial production

Method used

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  • Preparation of 2,3,4,5,6-pentafluorobenzyl alcohol
  • Preparation of 2,3,4,5,6-pentafluorobenzyl alcohol
  • Preparation of 2,3,4,5,6-pentafluorobenzyl alcohol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Weigh 20.0g of pentafluorobenzonitrile, 0.8g of RTH-312 type Raney-Ni (produced by Datong General Chemical Co., Ltd.), 80mL of methanol, and 11.7g of concentrated sulfuric acid into a 250mL autoclave, replace the gas with nitrogen three times, and pass through H 2 The pressure was 15 atm, the temperature was raised to 55°C, and after 13 hours of reaction, sampling and analysis were performed, the raw materials disappeared, the insoluble matter was filtered out, and the solvent was evaporated under reduced pressure to obtain 28.7 g of sulfate salt of pentafluorobenzylamine, content: 98.6% (HPLC) , Yield: 93.8%.

Embodiment 2

[0045] Weigh 20.0g of pentafluorobenzonitrile, 0.15g of 10% Pb / C (produced by Baoji Ruike Pharmaceutical Chemical Co., Ltd.), 55mL of ethanol, and 14.1g of oxalic acid into a 250mL autoclave, replace the gas with nitrogen three times, and pass through H 2 The pressure was 10 atm, the temperature was raised to 55°C, and after 14 hours of reaction, sampling and analysis were performed, the raw materials disappeared, the insoluble matter was filtered out, and the solvent was recovered under reduced pressure to obtain 28.1 g of oxalate of pentafluorobenzylamine, content: 98.8% (HPLC) , Yield: 94.2%.

Embodiment 3

[0047] Weigh 26.0g of pentafluorobenzonitrile, 1.2g of RTH-6120 Raney-Co (manufactured by Datong General Chemical Co., Ltd.), 65mL of DMF, and 19.2g of trifluoroacetic acid into a 250mL autoclave, replace the gas with nitrogen three times, and pass H2 To a pressure of 20atm, the temperature was raised to 58°C. After reacting for 15 hours, a sample was analyzed. The raw material disappeared, and the insoluble matter was filtered out. The solvent was recovered under reduced pressure to obtain 39.4 g of trifluoroacetate of pentafluorobenzylamine, content: 98.7% ( HPLC), yield: 94.0%.

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Abstract

The invention discloses a method for preparing 2, 3, 4, 5, 6-pentafluorophenylcarbinol. The preparation method comprises the following steps: using 2, 3, 4, 5, 6-pentafluorocyanobenzene as an initial raw material, introducing hydrogen in an organic solvent containing acid, and hydrogenating and reducing the raw material under the action of a catalyst at normal temperature of 70 DEG C and normal pressure of 30atm to obtain 2, 3, 4, 5, 6-pentafluorobenzylamine salt; and diazotizing the obtained 2, 3, 4, 5, 6-pentafluorobenzylamine salt and nitrite in an aqueous solution containing acid at a temperature of between 45 and 70 DEG C, then heating to a temperature of between 70 and 100 DEG C to carry out hydrolysis reaction, and after fully reacting, separating and drying the reaction liquid to obtain the 2, 3, 4, 5, 6-pentafluorophenylcarbinol. The method has the advantages that the product prepared by the method has high purity, and the total yield is more than 83 percent; the raw material cost is low, and the used solvent and catalyst can be recycled, so as to reduce pollution to environment; and diazotization and hydrolysis reaction are finished in one reactor in the whole reaction process, so the method has fewer steps, comparatively moderate conditions and simple operation, and is preferably applied to industrialized production.

Description

(1) Technical field [0001] The invention relates to a preparation method of 2,3,4,5,6-pentafluorobenzyl alcohol. (2) Background technology [0002] Penfluthrin (fenfluthrin) is a new high-efficiency and low-toxicity pyrethroid insecticide, which has high insecticidal activity, low dosage, low toxicity and no pollution to the environment, while 2, 3, 4, 5, 6 - Pentafluorobenzyl alcohol is a necessary intermediate for the synthesis of penfluthrin. In addition, 2,3,4,5,6-pentafluorobenzyl alcohol is also an important intermediate of fine chemicals such as pesticides and medicines, and has a wide range of applications. Therefore, the synthesis of pentafluorobenzyl alcohol has become an important research topic. The structural formula of 2,3,4,5,6-pentafluorobenzyl alcohol is as follows: [0003] [0004] 2,3,4,5,6-Pentafluorobenzyl alcohol [0005] 2,3,4,5,6-pentafluorobenzyl alcohol is mainly obtained by direct or indirect reduction of p-pentafluorobenzoic acid, and its ...

Claims

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Application Information

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IPC IPC(8): C07C33/46C07C29/09
CPCY02P20/584
Inventor 李秀珍杨郭明黄生建陈侠姜辉陈寅镐王超
Owner ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD
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