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Method for preparing 2, 7-dibromo-4-nitrofluorenone

A technology of nitrofluorenone and dibromofluorenone, which is applied in the field of aromatic organic compounds, can solve the problems of difficult separation and purification of reactants, large environmental pollution, complicated operation, etc., and achieves low cost, small environmental pollution and mild reaction conditions Effect

Inactive Publication Date: 2009-08-26
SHANXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Preparation of 2,7-dibromo-4-nitrofluorenone by the above method has low overall yield, high cost, difficulty in separation and purification of reactants, complicated operation, and great environmental pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] Operation steps: Add 1.66Kg fluorene (10mol), 7L tetrahydrofuran, 0.56Kg potassium hydroxide (10mol) into a 10L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 10 hours. The reaction liquid was suction filtered to remove potassium hydroxide, the filtrate was distilled to remove the solvent, and the obtained solid was washed with water three times and dried to obtain 1.75 kg of 9-fluorenone with a yield of 97.2% and a purity of more than 98.0%.

[0013] Add 1.75Kg (9.72mol) 9-fluorenone and 15L water into a 50L enamel reaction kettle equipped with a mechanical stirrer, reflux condensing device, thermometer and constant pressure dropping funnel, start stirring, heat, when the temperature rises to 80°C At this time, 2.45Kg (15.30mol) bromine was slowly added dropwise with a constant pressure dropping funnel, refluxed for 3h, cooled to room temperature, and the pH value of the system was adjusted...

Embodiment 2

[0016] Example 2 Preparation of 2,7-dibromo-4-nitrofluorenone

[0017] Operation steps: Add 1.66Kg fluorene (10mol), 7L tetrahydrofuran, 0.42Kg potassium hydroxide (7.5mol) into a 10L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 10 hours. The reaction solution was suction filtered to remove potassium hydroxide, the filtrate was distilled to remove the solvent, and the obtained solid was washed with water three times and dried to obtain 1.74Kg of 9-fluorenone with a yield of 96.7% and a purity of more than 98.0%.

[0018] Add 1.74Kg (9.67mol) 9-fluorenone and 15L water into a 50L enamel reaction kettle equipped with a mechanical stirrer, reflux condensing device, thermometer and constant pressure dropping funnel, start stirring, heat, when the temperature rises to 80°C At this time, 2.43Kg (15.18mol) bromine was slowly added dropwise with a constant pressure dropping funnel, refluxed for 4 hours,...

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PUM

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Abstract

The invention provides a method for preparing 2, 7-dibromo-4-nitrofluorenone, comprising the followings steps: carrying out oxidation reaction on fluorene to obtain 9-fluorenone; carrying out bromination reaction on the 9-fluorenone to obtain 2, 7-dibromofluorenone; adding the 2, 7-dibromofluorenone and water into a reactor by the weight ratio of 1: 4-6; blending and heating the mixture; when the temperature is 80-90 DEG C, dripping the mixed acid of nitric acid and sulphuric acid rapidly; reacting for 3-5h under reflux, wherein the mol ratio of the 2, 7-dibromofluorenone to nitric acid and sulphuric acid is 1:70-80:60-70; adding water for quenching reaction; filtering; re-crystallizing the obtained solid with tetrahydrofuran and water, and drying the crystal to obtain the 2, 7-dibromo-4-nitrofluorenone. In the bromination and nitrification processes, water is used as solvent. The invention has moderate reaction conditions, simple operation, high total yield (83-88%), low cost, less environmental pollution and easy achievement of industrialization.

Description

technical field [0001] The invention relates to an aromatic organic compound, in particular to a preparation method of 2,7-dibromo-4-nitrofluorenone. technical background [0002] 2,7-dibromo-4-nitrofluorenone, because of the introduction of multiple functional groups with different reactivity into the fluorenone molecule, is widely used as an important fine chemical intermediate in dyes, plastics, medicine and In the preparation of functional polymer materials, etc. At present, the preparation method of 2,7-dibromo-4-nitrofluorenone reported at home and abroad is mainly based on fluorene as raw material, bromination to obtain 2,7-dibromofluorene, and then nitration to obtain 2,7-dibromofluorene -4-nitrofluorene, and finally prepare 2,7-dibromo-4-nitrofluorenone by oxidation (Tetrahedron, 2003,59,3131; Makromol.Chem., 1989,190,231-240; J.Med. Chem., 1965, 8, 491-497). The preparation of 2,7-dibromo-4-nitrofluorenone by the above method has low overall yield, high cost, di...

Claims

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Application Information

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IPC IPC(8): C07C205/45C07C201/08
Inventor 张昭张鑫韩俊斌吉轩张鹏
Owner SHANXI UNIV