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Method for synthesizing 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene

A technology of dichloronitrobenzene and trifluorobenzene, applied in the field of organic synthesis, can solve the problems of group rearrangement isomerization, high fluorination reaction temperature, low product yield and the like

Active Publication Date: 2015-12-09
ZHEJIANG LINJIANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The yield of the product in this method is relatively low, the temperature of the fluorination reaction is relatively high, the groups on the benzene ring are prone to rearrangement and isomerization, and the purity and yield of the product are relatively low

Method used

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  • Method for synthesizing 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene
  • Method for synthesizing 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene
  • Method for synthesizing 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Synthesis of 1,3,5-trichloro-2,4-difluorobenzene:

[0054] Weigh 228.0g of 2,4-difluoro-3,5-dichloronitrobenzene, and throw it into a 500ml four-neck flask equipped with a mechanical stirrer, a thermometer, a ventilation duct, an air condenser, a receiving bottle and an exhaust gas absorption device, and heat up To 195°C, slowly pass chlorine gas under stirring, fix the chlorine gas flow rate at 4000L / h, rectify, stop the reaction when no more fractions flow out, adjust the pH of the fractions to 7 with 10% sodium bicarbonate aqueous solution, separate the organic layer, The organic layer was dried with anhydrous sodium sulfate and filtered to obtain 210.0 g of the product 1,3,5-trichloro-2,4-difluorobenzene, with a yield of 96.5% and a GC purity of 99%.

[0055] Same as embodiment 1 mode of operation, change the temperature of chlorination reaction, chlorine flow and reaction solvent in the chloride synthesis process, the results are shown in table 1:

[0056] Table 1...

Embodiment 7

[0059] Synthesis of 2,4,6-trichloro-3,5-difluoronitrobenzene:

[0060] Put 200g of sulfuric acid into the flask, then dropwise add 100g of 1,3,5-trichloro-2,4-difluorobenzene prepared in Example 1 into the flask, start stirring, raise the temperature to 80°C, and start to drop 59g A mixed acid solution with a mass ratio of sulfuric acid and nitric acid of 1:1; the dosage of nitric acid in the mixed acid solution is equivalent to 1.0 times the molar weight of 2,4,6-trichloro-3,5-difluoronitrobenzene After the completion, keep the reaction for 2 hours; after the reaction, spontaneously ignite and cool down and let it stand for 30 minutes, then start to separate layers, adjust the pH of the upper layer to 7 with aqueous sodium bicarbonate solution, dry the organic layer with anhydrous sodium sulfate, and filter to obtain the product 2,4 , 118.0 g of 6-trichloro-3,5-difluoronitrobenzene, the yield was 97.8%, and the GC purity of 2,4,6-trichloro-3,5-difluoronitrobenzene was 94%.

...

Embodiment 13

[0066] Synthesis of 1,3,5-trichloro-2,4,6-trifluorobenzene:

[0067] Throw 100g of 2,4,6-trichloro-3,5-difluoronitrobenzene prepared in Example 7 into the flask, heat up for dehydration, stop heating when the temperature reaches 140°C, and put in 30g of potassium fluoride and 2g Tetra-n-butylammonium chloride, heated up to 160°C for secondary dehydration, reacted at the reaction temperature for 4 hours, after the reaction was completed, washed with heated water, stirred for 30 minutes, left to separate and separated, and the materials were distilled to obtain the product 1,3 , 5-trichloro-2,4,6-trifluorobenzene 85.5g, yield 95.3%, GC purity 96%.

[0068] The difference from Example 13 is that the reaction temperature during the fluorination reaction, the reaction solvent, the reaction time, the equivalent of potassium fluoride added, the results are shown in Table 3:

[0069] table 3

[0070]

[0071] As can be seen from Table 3, the reaction temperature and the feeding a...

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Abstract

The invention discloses a method for synthesizing 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene. The method comprises performing chlorination reaction on 2,4-difluoro-3,5-dichloronitrobenzene in chlorine atmosphere to obtain a chloride, and controlling the chlorination reaction temperature to 160-195 DEG C; performing nitration reaction on the chloride in a mixed acid solution of sulfuric acid and nitric acid to obtain a nitro compound, and controlling the nitration reaction temperature to 60-110 DEG C; and performing fluorination reaction on the nitro compound with a fluoride under a waterless condition so as to obtain 1,3,5-trichloro-2,4,6-trifluorobenzene, and controlling the fluorination reaction temperature to 80-200 DEG C. The product synthesized by the method is high in selectivity, and the yield and the purity of products of all steps are relatively high, and operation is simple.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to the synthesis of 1,3,5-trichloro-2,4,6-trifluorobenzene from 2,4-difluoro-3,5-dichloronitrobenzene. Background technique [0002] 1,3,5-Trichloro-2,4,6-trifluorobenzene is a relatively common pharmaceutical intermediate and material intermediate; CAS: 319-88-0; melting point 62-64°C; boiling point 79.5°C (12mmHg) . [0003] The chemical structural formula of 1,3,5-trichloro-2,4,6-trifluorobenzene is shown in Formula 1: [0004] [0005] Fluorobenzene and Cl 2 in FeCl 3 Catalyzed chlorination reaction can synthesize 4-chlorofluorobenzene, when Cl 2 In excess, it can be further reacted to generate isomer mixtures of 2,4-dichlorofluorobenzene and 3,4-dichlorofluorobenzene (see J.IndianChem.Soc., 1944(21):112-114). [0006] Zhu Shungen reviewed a synthetic method of 2,4-dichlorofluorobenzene (Zhu Shungen, Synthesis and progress of 2,4-dichlorofluorobenzene, Shangh...

Claims

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Application Information

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IPC IPC(8): C07C25/13C07C17/093
Inventor 易苗陈刚强吴然
Owner ZHEJIANG LINJIANG CHEM
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