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Method for preparing 2-bromine-5-fluorobenzotrifluoride

A technology for fluorotrifluorotoluene and m-fluorotrifluorotoluene, which is applied in the field of preparation of chemical intermediates, can solve problems such as difficulty in processing, and achieve the effects of simple post-processing, high reaction yield, and reduced production cost

Active Publication Date: 2015-12-16
JIANGSU YONGCHUANG PHARMA TECH CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Glacial acetic acid, sulfuric acid, and the residues after the bromide ions of dibromohydantoin leave are mixed together, and post-processing is difficult

Method used

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  • Method for preparing 2-bromine-5-fluorobenzotrifluoride

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Example 1: Synthesis of 2-bromo-5-fluorobenzotrifluoride: In a 2000ml three-necked flask, add 400g of concentrated sulfuric acid, 400g of m-fluorobenzotrifluoride, 2g of lithium bromide, 4g of iron bromide, and tetrabutyl bromide successively under stirring in an external water bath Ammonium chloride 4g, bromine 195.1g, controlled temperature 35-45 ℃ for 6h, sampling, GC detection raw material 0.65%. Cool down to below 30°C, filter out the catalyst, transfer to a 2000ml separating funnel, stand still for 1h, separate out the base acid, put the crude product in a 2000ml bottle, add 1000g of water while stirring, drop in 5% sodium hydroxide solution to adjust the pH =7, complete static separation to obtain crude product 550g, yield 92%, content 96%, content 98% through vacuum distillation.

Embodiment 2

[0024] Example 2: In a 2000ml three-necked bottle, add the above batch of separated base acid, then add 400g of m-fluorobenzotrifluoride, 2g of lithium bromide, 4g of iron bromide, 4g of tetrabutylammonium bromide, and 200g of bromine in sequence, and control the temperature at 35-45°C After reacting for 6h, sampling was carried out, and 0.92% of the raw material was detected by GC. Cool down to below 30°C, filter out the catalyst, transfer to a 2000ml separating funnel, stand still for 1h, separate out the base acid, put the crude product in a 2000ml bottle, add 1000g of water while stirring, drop in 5% sodium hydroxide solution to adjust the pH =7, complete static separation to obtain crude product 540g, yield 91.1%, content 95.6%, content 98% through vacuum distillation.

Embodiment 3

[0025] Example 3: In a 2000ml three-necked bottle, add the above batch of separated bottom acid, then add 400g of m-fluorobenzotrifluoride, 2g of lithium bromide, 4g of iron bromide, 4g of tetrabutylammonium bromide, and 235g of bromine in sequence, and control the temperature at 35-45°C After reacting for 6h, sampling was carried out, and 0.92% of the raw material was detected by GC. Cool down to below 30°C, filter out the catalyst, transfer to a 2000ml separating funnel, stand still for 1h, separate out the base acid, put the crude product in a 2000ml bottle, add 1000g of water while stirring, drop in 5% sodium hydroxide solution to adjust the pH =7, complete static separation to obtain crude product 545g, yield 91.9%, content 95.8%, content 98% through vacuum distillation.

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PUM

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Abstract

The invention discloses a method for preparing 2-bromine-5-fluorobenzotrifluoride. According to the preparation method, fluorobenzotrifluoride serves as a raw material, under the condition of concentrated sulfuric acid and composite catalysts, bromine is stirred and added dropwise, and 2-bromine-5-fluorobenzotrifluoride is obtained after separation and purification. The yield reaches over 91.1%, the reaction conversion rate is larger than 99%, and selectivity is 92-95%. The raw material applied in the reaction process is convenient to purchase, production cost is low, waste acid obtained in the reaction process can be recycled, post-processing is easy, and the whole technology does not generate a large amount of wastewater containing salt and organic matter. Economic benefits and social benefits are good.

Description

technical field [0001] The invention relates to the field of preparation of chemical intermediates, in particular to a preparation method of the chemical intermediate 2-bromo-5-fluorobenzotrifluoride. Background technique [0002] 2-Bromo-5-fluorobenzotrifluoride has the molecular formula C 7 h 3 BrF 4 , with a molecular weight of 243; it has a wide range of uses and can be prepared as an organic reagent, and at the same time it can also prepare pharmaceutical intermediates or pesticide intermediates. At present, there are two main process routes for domestic production of this product: [0003] 1) m-fluorobenzotrifluoride is nitrated and reduced to obtain 2-amino-5-fluorobenzotrifluoride, and 2-amino-5-fluorobenzotrifluoride is diazotized and brominated to obtain the product. The expensive raw materials of this process route are almost the same as the price of this product. [0004] 2) In the presence of glacial acetic acid and sulfuric acid, m-fluorotrifluorotoluene i...

Claims

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Application Information

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IPC IPC(8): C07C25/13C07C17/12
Inventor 杨桦孙德明高于王总超
Owner JIANGSU YONGCHUANG PHARMA TECH CO LTD
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