Preparation of 2,3,5,6-tetrafluorobenzyl alcohol

A technology of tetrafluorobenzyl alcohol and tetrafluorobenzonitrile, which is applied in the field of synthesis of chemical intermediates, can solve problems such as increasing costs and increasing environmental pollution, and achieves the effects of reducing by-products, reducing pollution, and cheap and easy-to-obtain raw materials

Inactive Publication Date: 2009-06-24
ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0023] The route uses organic tertiary amines (such as N,N-dimethylbenzylamine) and metal chloride salts as catalysts in methanol to reduce 2,3,5,6-tetrafluorobenzoic acid with sodium borohydride

Method used

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  • Preparation of 2,3,5,6-tetrafluorobenzyl alcohol
  • Preparation of 2,3,5,6-tetrafluorobenzyl alcohol
  • Preparation of 2,3,5,6-tetrafluorobenzyl alcohol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment I-1

[0066] Weigh 33.3g of pentafluorobenzonitrile, 1.6g of RTH-311 type Raney-Ni (produced by Datong General Chemical Co., Ltd.), 83.0mL of methanol, and 17.3g of concentrated sulfuric acid into a 250mL autoclave, replace the gas with nitrogen three times, pass h 2 When the pressure is 25 atm, the temperature is raised to 55° C. After reacting for 14 hours, sampling analysis is performed, the raw materials disappear, the insoluble matter is filtered out, and the solvent is recovered under reduced pressure to obtain 48.8 g of sulfate salt of pentafluorobenzylamine, content: 98.5% (HPLC), Yield: 94.4%.

Embodiment I-2

[0068] Weigh 30.0g of pentafluorobenzonitrile, 1.5g of RTH-411 type Raney-Ni (produced by Datong General Chemical Co., Ltd.), 120mL of ethanol, and 26.5g of trifluoroacetic acid into a 250mL autoclave, replace the gas with nitrogen three times, and pass h 2 When the pressure is 20 atm, the temperature is raised to 60° C., reacted for 16 hours, sampling analysis, the raw material disappears, the insoluble matter is filtered out, and the solvent is recovered under reduced pressure to obtain 45.5 g of trifluoroacetate of pentafluorobenzylamine, content: 98.2% (HPLC ), yield: 94.0%.

Embodiment I-3

[0070] Weigh 20.5g of pentafluorobenzonitrile, 0.2g of 10% Pd / C (produced by Baoji Ruike Pharmaceutical Chemical Co., Ltd.), 70mL of THF, and 9.5g of acetic acid into a 250mL autoclave, replace the gas with nitrogen three times, and pass H 2 When the pressure is 10 atm, the temperature is raised to 55° C. After reacting for 10 hours, sampling analysis is carried out, the raw materials disappear, the insoluble matter is filtered out, and the solvent is recovered under reduced pressure to obtain 25.6 g of acetate of pentafluorobenzylamine, content: 97.9% (HPLC) , Yield: 93.8%.

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Abstract

The invention discloses a preparation method of 2, 3, 5, 6-phenylcarbinol tetrafluoride; the preparation method is as follows: the 2, 3, 4, 5, 6-cyanobenzene pentafluoride is taken as initial raw material; cyano group is firstly reduced by catalytic hydrogenation, and then diazotization and hydrolysis reaction are carried out for obtaining hydroxide radical, and then contraposition defluorination is carried out for obtaining the 2, 3, 5, 6-phenylcarbinol tetrafluoride; or the 2, 3, 4, 5, 6-cyanobenzene pentafluoride is taken as initial raw material, the contraposition defluorination is carried out for obtaining the 2, 3, 5, 6-cyanobenzene pentafluoride, the hydroxide radical is reduced by the catalytic hydrogenation, and then the diazotization and the hydrolysis reaction are carried out for obtaining the 2, 3, 5, 6-phenylcarbinol tetrafluoride. The two synthetic routes of the invention both comprises the three reaction steps of catalytic hydrogenation, diazotization and hydrolysis and contraposition defluorination; wherein, in the catalytic hydrogenation process, acid is added for obtaining amine salt, and the diazotization and the hydrolysis reaction are carried out by a one pot process, thus leading byproducts to be greatly reduced, the main products to have high purity and the yield coefficient to reach more than 74 percent; in addition, the whole process has simple operation, mild reaction condition and cheap and easily obtained raw material; catalyst and solvent can be recycled and used, thus reducing pollution, being environment-friendly, having economic value and being suitable for industrialization.

Description

(1) Technical field [0001] The invention belongs to the field of synthesis of chemical drug intermediates, in particular to a preparation method of 2,3,5,6-tetrafluorobenzyl alcohol. (2) Background technology [0002] Transfluthrin (transfluthrin) is a pyrethrin insecticide developed and produced by German Bayer Company in the 1980s. It is mainly used for the prevention and control of sanitary pests, and has the effect of quickly striking and killing. At present, few domestic manufacturers produce it, and it is a pyrethroid pesticide with great market prospects. 2,3,5,6-Tetrafluorobenzyl alcohol is an important intermediate in the synthesis of the pyrethroid insecticide transfluthrin. Therefore, the synthesis of 2,3,5,6-tetrafluorobenzyl alcohol has become an important research topic. The structural formula of 2,3,5,6-tetrafluorobenzyl alcohol is as follows, [0003] [0004] 2,3,5,6-Tetrafluorobenzyl alcohol [0005] 2,3,5,6-Tetrafluorobenzyl alcohol is mainly obtain...

Claims

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Application Information

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IPC IPC(8): C07C39/27C07C37/045
Inventor 杨郭明李秀珍黄生建陈侠姜辉陈寅镐王超
Owner ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD
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