Method for preparing 9-fluorenone with fluorene

Abstract

The invention discloses a method for preparing 9-fluorenone with fluorine.Fluorine serves as the raw material, alkali serves as a catalyst, an organic solvent containing aromatic nucleus and water serve as solvents, crown ether serves as a phase transfer agent, and 9-fluorenone is prepared.The preparation method includes the step that industrial fluorine and high-purity fluorine are used for preparing industrial 9-fluorenone and high-purity 9-fluorenone respectively.Under the conditions, the fluorine conversion rate can reach 100%, and selectivity of fluorenone is 100%.After a reaction solution is cooled and crystal fluorenone is separated out, filter liquid containing the solvents, alkali, crown ether, fluorine and fluorenone is directly recycled, the solvents in reaction tail gas are absorbed with high-boiling-point solvents, and the chemical synthesis technology saves energy and is environmentally friendly.

Description

technical field

[0001] The invention relates to a method for preparing 9-fluorenone (fluorenone for short) by catalyzing the oxidation of fluorene by a phase transfer method, belonging to the field of organic synthesis. Background technique

[0002] Fluorene is one of the important components of coal tar, accounting for 1-2% of the total amount of coal tar. The cost of separating fluorene from tar is relatively low. At present, most of the industrial products of fluorene isolated have a purity of ≥95%. Fluorene can be converted into various substituted fluorene derivatives, such as hydrocarbyl substituted fluorene, halogenated fluorene, nitrofluorene, acyl fluorene, carboxy fluorene, etc. 9-Fluorenone, referred to as fluorenone, is a derivative of fluorene that is further processed from fluorene. The purity of industrial fluorenone is required to be ≥95%. Fluorenone derivatives include the corresponding derivatives of 9-fluorenone obtained by converting various substitute...

Examples

Embodiment 1

[0064] Add 42.00g of industrial fluorene with a mass fraction of 95.44%, 18-crown-63.20g, and 45ml of xylene to a 250ml four-necked flask in sequence, adjust the temperature of the water bath to maintain 50°C, and use α-methylnaphthalene to absorb the solvent entrained in the tail gas , start the mechanical stirring, adjust the stirring rate to 300 rpm, after stirring for 10 minutes, add 6.70g KOH and 10.0ml water. After mixing evenly, start feeding 300mlx2 / min of clean and moist air, record the reaction time, and track the reaction with thin-layer chromatography. After reacting for 10 hours, the spot of fluorene disappeared, and the reaction was continued for 1 hour, and the sample was taken for gas chromatography analysis. Compared with the chromatogram of fluorene raw material, the peak of fluorene was missing, and only the peak of fluorenone was increased. Cool the reaction solution, crystallize the fluorenone, filter the mixture, recover the filtrate for recycling, wash t...

Embodiment 2

[0066]Except replacing 6.7g potassium hydroxide with 8.4g potassium hydroxide, other is the same as embodiment 1. After reacting for 5 hours, thin-layer chromatography showed that the spots of the fluorene raw material disappeared, and the reaction was stopped after continuing the reaction for 1 hour. Chromatographic analysis of the reaction solution showed 100% conversion of fluorene, and only one peak of fluorenone was added. Cool the reaction solution, crystallize the fluorenone, filter the mixture, recover the filtrate for recycling, wash the crystal fluorenone with a small amount of water, and place the crystal in the air to dry naturally. Weighing 30.73g, its purity was 100% by gas chromatography analysis.

Embodiment 3

[0068] Add 45ml of xylene, 62.62g of industrial fluorene, 64.80g of 18-crown-64.80g, 10.0ml of 45wt% KOH solution according to the procedure of Example 1, and the temperature of the water bath is 58°C. After reacting for 7 hours, thin-layer chromatography showed that the spot of fluorene raw material disappeared, and the reaction was stopped after continuing to react for 1 hour. Chromatographic analysis of the reaction solution showed 100% conversion of fluorene, and only one peak of fluorenone was added. Cool the reaction solution, fluorenone crystallizes, filter the mixture, recover the filtrate for use, wash the crystal fluorenone with a small amount of water, and place the crystal in the air to dry naturally. Weighing 50.12g, its purity was 100% by gas chromatography analysis.

technical field

[0001] The invention relates to a method for preparing 9-fluorenone (fluorenone for short) by catalyzing the oxidation of fluorene by a phase transfer method, belonging to the field of organic synthesis. Background technique

[0002] Fluorene is one of the important components of coal tar, accounting for 1-2% of the total amount of coal tar. The cost of separating fluorene from tar is relatively low. At present, most of the industrial products of fluorene isolated have a purity of ≥95%. Fluorene can be converted into various substituted fluorene derivatives, such as hydrocarbyl substituted fluorene, halogenated fluorene, nitrofluorene, acyl fluorene, carboxy fluorene, etc. 9-Fluorenone, referred to as fluorenone, is a derivative of fluorene that is further processed from fluorene. The purity of industrial fluorenone is required to be ≥95%. Fluorenone derivatives include the corresponding derivatives of 9-fluorenone obtained by converting various substitute...

Examples

Embodiment 1

[0064] Add 42.00g of industrial fluorene with a mass fraction of 95.44%, 18-crown-63.20g, and 45ml of xylene to a 250ml four-necked flask in sequence, adjust the temperature of the water bath to maintain 50°C, and use α-methylnaphthalene to absorb the solvent entrained in the tail gas , start the mechanical stirring, adjust the stirring rate to 300 rpm, after stirring for 10 minutes, add 6.70g KOH and 10.0ml water. After mixing evenly, start feeding 300mlx2 / min of clean and moist air, record the reaction time, and track the reaction with thin-layer chromatography. After reacting for 10 hours, the spot of fluorene disappeared, and the reaction was continued for 1 hour, and the sample was taken for gas chromatography analysis. Compared with the chromatogram of fluorene raw material, the peak of fluorene was missing, and only the peak of fluorenone was increased. Cool the reaction solution, crystallize the fluorenone, filter the mixture, recover the filtrate for recycling, wash t...

Embodiment 2

[0066]Except replacing 6.7g potassium hydroxide with 8.4g potassium hydroxide, other is the same as embodiment 1. After reacting for 5 hours, thin-layer chromatography showed that the spots of the fluorene raw material disappeared, and the reaction was stopped after continuing the reaction for 1 hour. Chromatographic analysis of the reaction solution showed 100% conversion of fluorene, and only one peak of fluorenone was added. Cool the reaction solution, crystallize the fluorenone, filter the mixture, recover the filtrate for recycling, wash the crystal fluorenone with a small amount of water, and place the crystal in the air to dry naturally. Weighing 30.73g, its purity was 100% by gas chromatography analysis.

Embodiment 3

[0068] Add 45ml of xylene, 62.62g of industrial fluorene, 64.80g of 18-crown-64.80g, 10.0ml of 45wt% KOH solution according to the procedure of Example 1, and the temperature of the water bath is 58°C. After reacting for 7 hours, thin-layer chromatography showed that the spot of fluorene raw material disappeared, and the reaction was stopped after continuing to react for 1 hour. Chromatographic analysis of the reaction solution showed 100% conversion of fluorene, and only one peak of fluorenone was added. Cool the reaction solution, fluorenone crystallizes, filter the mixture, recover the filtrate for use, wash the crystal fluorenone with a small amount of water, and place the crystal in the air to dry naturally. Weighing 50.12g, its purity was 100% by gas chromatography analysis.

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