Method for preparing 2-bromo-7-nitrofluorenone

Abstract

A method for preparing 2-bromo-7-nitrofluorenone comprises the followings steps: carrying out oxidation reaction on fluorene to obtain 9-fluorenone; carrying out bromination reaction on the 9-fluorenone to obtain 2-bromofluorenone; adding 2-bromofluorenone and water into a reactor by the weight ratio of 1:7-9; 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 2.5-4h under reflux, wherein the mol ratio of 2-bromofluorenone to nitric acid and sulphuric acid is 1:25-35:30-40; adding water for quenching reaction; filtering; re-crystallizing the obtained solid with methanol and glacial acetic acid; and drying the crystal to obtain the 2-bromo-7-nitrofluorenone. In the bromination and nitrification processes, water is used as solvent. The invention has moderate reaction conditions, simple operation, high total yield (above 83%), low cost, less environmental pollution and easy achievement of industrialization.

Description

technical field

[0001] The invention relates to aromatic compounds, in particular to a preparation method of 2-bromo-7-nitrofluorenone. Background technique

[0002] As an important fine chemical intermediate, the fluorene derivative 2-bromo-7-nitrofluorenone is widely used in the preparation of dyes, medicines and functional polymer materials. At present, the preparation method of 2-bromo-7-nitrofluorenone reported at home and abroad is mainly based on fluorene as raw material, brominated to obtain 2-bromofluorene, and then nitrated to obtain 2-bromo-7-nitrofluorene, and finally passed Oxidative preparation of 2-bromo-7-nitrofluorenone. The preparation method has low total yield, high cost, difficult separation and purification of reactants, complicated operation and great environmental pollution. Contents of the invention

[0003] The purpose of the present invention is to provide a preparation method of 2-bromo-7-nitrofluorenone with mild reaction conditions, simple a...

Examples

Embodiment 1

[0012] Operation steps: Add 166g of fluorene (1.0mol), 0.75L of tetrahydrofuran, and 56g of potassium hydroxide (1.0mol) into a 2.5L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 8 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 173.7 g of 9-fluorenone with a yield of 96.5% and a purity of more than 98.0%.

[0013] Add 173.7g (0.965mol) 9-fluorenone and 0.6L water in a 2.5L four-necked round bottom flask equipped with a mechanical stirrer, a reflux condenser, a thermometer and a constant pressure dropping funnel, start stirring, and heat in a water bath. When the temperature rises to 75°C, gradually add 185.3g (1.158mol) Br 2 After about 1.0h dropwise addition, react at 80°C for 3h; cool to room temperature, add 0.3L saturated sodium bisulfi...

Embodiment 2

[0017] Operation steps: Add 166g of fluorene (1.0mol), 0.75L of tetrahydrofuran, and 42g of potassium hydroxide (0.75mol) into a 2.5L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 8 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 175.0 g of 9-fluorenone with a yield of 97.2% and a purity of more than 98.0%.

[0018] Add 175.0g (0.972mol) 9-fluorenone and 0.6L water in a 2.5L four-necked round bottom flask equipped with a mechanical stirrer, a reflux condenser, a thermometer and a constant pressure dropping funnel, start stirring, and heat in a water bath. When the temperature rises to 75°C, gradually add 185.3g (1.147mol) Br 2 After about 1.0h dropwise addition, react at 80°C for 3h; cool to room temperature, add 0.3L saturated sodium bisu...

technical field

[0001] The invention relates to aromatic compounds, in particular to a preparation method of 2-bromo-7-nitrofluorenone. Background technique

[0002] As an important fine chemical intermediate, the fluorene derivative 2-bromo-7-nitrofluorenone is widely used in the preparation of dyes, medicines and functional polymer materials. At present, the preparation method of 2-bromo-7-nitrofluorenone reported at home and abroad is mainly based on fluorene as raw material, brominated to obtain 2-bromofluorene, and then nitrated to obtain 2-bromo-7-nitrofluorene, and finally passed Oxidative preparation of 2-bromo-7-nitrofluorenone. The preparation method has low total yield, high cost, difficult separation and purification of reactants, complicated operation and great environmental pollution. Contents of the invention

[0003] The purpose of the present invention is to provide a preparation method of 2-bromo-7-nitrofluorenone with mild reaction conditions, simple a...

Examples

Embodiment 1

[0012] Operation steps: Add 166g of fluorene (1.0mol), 0.75L of tetrahydrofuran, and 56g of potassium hydroxide (1.0mol) into a 2.5L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 8 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 173.7 g of 9-fluorenone with a yield of 96.5% and a purity of more than 98.0%.

[0013] Add 173.7g (0.965mol) 9-fluorenone and 0.6L water in a 2.5L four-necked round bottom flask equipped with a mechanical stirrer, a reflux condenser, a thermometer and a constant pressure dropping funnel, start stirring, and heat in a water bath. When the temperature rises to 75°C, gradually add 185.3g (1.158mol) Br 2 After about 1.0h dropwise addition, react at 80°C for 3h; cool to room temperature, add 0.3L saturated sodium bisulfi...

Embodiment 2

[0017] Operation steps: Add 166g of fluorene (1.0mol), 0.75L of tetrahydrofuran, and 42g of potassium hydroxide (0.75mol) into a 2.5L three-necked flask equipped with a mechanical stirrer and a reflux condenser, start stirring, and react at room temperature for 8 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 175.0 g of 9-fluorenone with a yield of 97.2% and a purity of more than 98.0%.

[0018] Add 175.0g (0.972mol) 9-fluorenone and 0.6L water in a 2.5L four-necked round bottom flask equipped with a mechanical stirrer, a reflux condenser, a thermometer and a constant pressure dropping funnel, start stirring, and heat in a water bath. When the temperature rises to 75°C, gradually add 185.3g (1.147mol) Br 2 After about 1.0h dropwise addition, react at 80°C for 3h; cool to room temperature, add 0.3L saturated sodium bisu...