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Preparation method of 2.3-difluoro-5-bromophenol

A technology of bromophenol and difluoroanisole is applied in the field of preparation of 2.3-difluoro-5-bromophenol, can solve problems such as low yield, inconsistent electronic effect, few products, etc., achieves high purity and is easy to purify Effect

Inactive Publication Date: 2006-06-21
FUXIN JINHONGTAI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

(1) The raw material 2.3-difluorophenol and 2.3-difluoro-6-nitrophenol in the route of (2) are not only expensive, but also difficult to obtain
In addition, the substituents on the benzene ring of the two raw materials have inconsistent positioning effects and electronic effects, resulting in many isomers produced during bromination, few products and difficult separation, high cost, low yield, and high requirements for industrial production equipment. Not easy to industrialize

Method used

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  • Preparation method of 2.3-difluoro-5-bromophenol
  • Preparation method of 2.3-difluoro-5-bromophenol
  • Preparation method of 2.3-difluoro-5-bromophenol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Nitration reaction: Synthesis of 2.3-difluoro-4-nitroanisole

[0021] (1) Ingredients and Mixing:

[0022] 2.3-Difluoroanisole: Concentrated sulfuric acid: Potassium nitrate 1:2:1~1.5(mol)

[0023] (2) Loading and operation

[0024] 1000ml three-necked glass reaction flask, equipped with mechanical stirring and thermometer, then add 144g of 2.3-difluoroanisole, 200g of concentrated sulfuric acid, 10g of cetyltrimethylammonium bromide, 75g of water, cool down in an ice-salt water bath below 10°C and stir , adding potassium nitrate kNO 3 106g, the total volume of the reaction mixture should not exceed 2 / 3 of the total volume of the reaction bottle. Stir for 8 hours below 10°C, track with the gas chromatograph, until no raw materials remain, put into ice water and suction filter to obtain a yellow-white solid, wash and dry .

[0025] (3) Purification treatment:

[0026] The dried solid was recrystallized from ethanol, and dried by suction filtration to obtain 180 g...

Embodiment 2

[0056] 1. Nitration reaction: Synthesis of 2.3-difluoro-4-nitroanisole

[0057] (1) Ingredients and Mixing

[0058] 2.3-Difluoroanisole: concentrated sulfuric acid: potassium nitrate = 1: 2: 1.05 (mol)

[0059] (2) Loading and operation

[0060] 500ml three-necked glass reaction flask, equipped with mechanical stirring and a thermometer, then add 72g of 2.3-difluoroanisole, 100g of concentrated sulfuric acid, 5g of cetyltrimethylammonium bromide, 38g of water, and stir in an ice-salt water bath to cool down below 10°C , adding potassium nitrate KNO 3 53g, after the addition, the total volume of the reaction mixture should not exceed 2 / 3 of the total volume of the reaction bottle. Stir for 8 hours below 10°C, track with the gas chromatograph, until no raw materials are left, put into ice water and suction filter to obtain a yellow-white solid. Wash and tumble dry.

[0061] (3) Purification treatment

[0062] The dried solid was recrystallized with ethanol, filtered and dri...

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PUM

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Abstract

The invention relates to the fluorine compounds, especially relating to the method for preparing 2.3-difluoramine-5-bromophenol, employing 2.3-difluoramineanisole as raw material and reacting with concentrated sulfuric acid and potassium nitrate for nitration, getting the nitration product 2.3-difluoramine-4-nitroanisole I, which reacts with stannous chloride through hydrazine hydrate for reduction reaction to produce 2.3 -difluoramine-4-amidoanisole product II, which reacts with bromine for oxo-reactionin dichloromethane to produce product 2.3-difluoramine-4-amido-5-bromoamido III, which produces 2.3-difluoramine-5-bromo difluoramine IV through hypophosphorous acid deamido reaction, which strips metyl group by aluminium chloride to produce final product 2.3-difluoramine-5-bromophenol V, the invention is characterized by easy-to-get raw material, scientific process, simple operation, low cost, high benefit, easy for industrial production and application for liquid crystal intermediate containing fluorine.

Description

Technical field [0001] The invention belongs to fluorine compounds, in particular to a preparation method of 2.3-difluoro-5-bromophenol. Background technique [0002] After searching, there is no preparation method of 2.3-difluoro-5-bromophenol reported in patents, non-patent literature and Aidrich at present at home and abroad. According to the classic technology and theory, the synthesis of 2.3-difluoro-5-bromophenol can be Through the following route: (1) take 2.3-difluorophenol as raw material, obtain 2.3-difluoro-6-bromophenol by direct bromination in dichloromethane solvent; 2.3-difluoro-5-bromophenol; 2.3-difluoro The three products of -4-bromophenol can only be separated by a special column to obtain 2.3-difluoro-5-bromophenol. (2) With 2.3-difluoro-6-nitrophenol as raw material, through hydrogenation reduction; bromination agent bromination, separation and purification, can obtain a small amount of 2.3-difluoro-5-bromophenol, and due to substituent functional group...

Claims

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Application Information

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IPC IPC(8): C07C37/055C07C39/02
Inventor 汤纯忠明少田郝志明周广金暴红陈静
Owner FUXIN JINHONGTAI CHEM
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