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Method for synthesizing 1-bromo-2,4,5-trifluorobenzene

A synthesis method and technology of trifluorobenzene, which are applied in chemical instruments and methods, halogenated hydrocarbon preparation, organic chemistry and other directions, can solve the problems of difficult separation and purification, complex synthesis process, expensive raw materials, etc., and achieve low cost and high yield. High, low environmental pollution effect

Inactive Publication Date: 2010-06-09
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the synthesis of 1-bromo-2,4,5-trifluorobenzene is carried out by using 1,2,4,5-tetrabromofluorobenzene, but its raw material price is relatively expensive, the synthesis process is complicated, and the purity of the obtained product is low , and not easy to separate and purify

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] 1,2,4-Trifluorobenzene 13.2g (100mmol), CCl 4 25ml, iron powder 0.16g (2.857mmol), mechanically stirred, heated to 45°C, add a constant pressure titration funnel on the reflux condenser, install a drying tube on the constant pressure titration funnel, slowly add liquid bromine 12.0g (75mmol) After 4 hours, the drop was completed, the temperature was raised to 65°C and 49 mg (0.298 mmol) of azobisisobutyronitrile was added, stirred for 2 hours, the temperature was raised to 82°C, and the reaction was carried out for 3 hours. Cool, add 30ml of 20% sodium bisulfite solution, stir for 10 minutes, separate the organic layer, wash with 10% sodium hydroxide lotion until the pH value is 8, and wash with anhydrous MgSO 4 Drying, filtering, and concentrating the filtrate to obtain 12.1 g of the product, the purity detected by HPLC was 99.2%, and 1H-NMR (CDCl 3 )δ: 7.38 (m, H, Ar-H), 7.02 (m, H, Ar-H), 1-bromo-2,4,5-trifluorobenzene, yield 57%.

Embodiment 2

[0016] 1,2,4-Trifluorobenzene 13.2g (100mmol), CCl 4 25ml, 0.2g (3.571mmol) of iron powder, mechanical stirring, heating to 45°C, adding a constant pressure titration funnel to the reflux condenser, installing a drying tube on the constant pressure titration funnel, slowly adding 12.0g (75mmol) of liquid bromine dropwise After 4 hours, dropwise was completed, the temperature was raised to 65°C, 66 mg (0.402 mmol) of azobisisobutyronitrile was added, stirred for 2 hours, the temperature was raised to 92°C, and the reaction was carried out for 4 hours. Cool, add 30ml of 20% sodium bisulfite solution, stir for 10 minutes, separate the organic layer, wash with 10% sodium hydroxide lotion until the pH value is 8, and wash with MgSO 4 Drying, filtering, and concentrating the filtrate to obtain 13.9 g of the product, the purity detected by HPLC was 99.2%, and 1H-NMR (CDCl 3 )δ: 7.38 (m, H, Ar-H), 7.02 (m, H, Ar-H), 1-bromo-2,4,5-trifluorobenzene, yield 66%.

Embodiment 3

[0018] 1,2,4-Trifluorobenzene 13.2g (100mmol), CCl 4 25ml, iron powder 0.25g (4.464mmol), mechanically stirred, heated to 45°C, add a constant pressure titration funnel on the reflux condenser, install a drying tube on the constant pressure titration funnel, slowly add liquid bromine 12.0g (75mmol) After 4 hours, the drop was completed, the temperature was raised to 65°C, 82 mg (0.499 mmol) of azobisisobutyronitrile was added, stirred for 2 hours, the temperature was raised to 102°C, and the reaction was carried out for 5 hours. Cool, add 30ml of 20% sodium bisulfite solution, stir for 10 minutes, separate the organic layer, wash with 10% sodium hydroxide lotion until the pH value is 8, and wash with anhydrous MgSO 4 Drying, filtering, and concentrating the filtrate to obtain 13.4 g of the product, the purity detected by HPLC is 99.2%, 1H-NMR (CDCl 3 )δ: 7.38 (m, H, Ar-H), 7.02 (m, H, Ar-H), 1-bromo-2,4,5-trifluorobenzene, yield 64%.

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Abstract

The invention relates to a synthesis method of 1-bromine-2, 4, 5-trifluoro-benzene, which adds iron powder and 1, 2, 4-trifluoro-benzene into organic solvent, adds liquid bromine at 43-48DEG C in 3-4h, increases temperature to 62-68DEG C, adds azobisisobutyronitrile, mixes, reacts at 82-102DEG C completely to obtain reaction solution, to be purified to obtain 1-bromine-2, 4, 5-trifluoro-benzene. The mass ratio between the 1-bromine-2, 4, 5-trifluoro-benzene, liquid bromine, iron powder, and azobisisobutyronitrile is 1:0.5-1.5:0.025-0.050:0.002-0.006, the organic solvent is azobisisobutyronitrile or chloroform, of which the volume is 250-300ml / mol according to 1-bromine-2, 4, 5-trifluoro-benzene. Compared with prior synthesis method of 1-bromine-2, 4, 5-trifluoro-benzene, the invention hashigh yield, low cost, simple process and little environment pollution.

Description

(1) Technical field [0001] The invention discloses a new method for synthesizing 1-bromo-2,4,5-trifluorobenzene. (2) Background technology [0002] 1-Bromo-2,4,5-trifluorobenzene is an important intermediate of broad-spectrum antibacterial quinolones. Its English name is: 1-bromo-2,4,5-trifluorobenzene. 19°C, boiling point 144°C, flash point 55°C, refractive index 1.4860, specific gravity 1.758. At present, the synthesis of 1-bromo-2,4,5-trifluorobenzene is carried out by using 1,2,4,5-tetrabromofluorobenzene, but its raw material price is relatively expensive, the synthesis process is complicated, and the purity of the obtained product is low , and not easy to separate and purify. (3) Contents of the invention [0003] The object of the present invention is to provide a method for synthesizing 1-bromo-2,4,5-trifluorobenzene with low cost and low pollution. [0004] For achieving the purpose of the invention, the technical scheme adopted by the present invention is: ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C17/12C07C25/13
Inventor 颜继忠关启明饶国武
Owner ZHEJIANG UNIV OF TECH
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