Synthesis technique of 9-fluorenone

Abstract

The invention relates to a synthesis technique of 9-fluorenone, which comprises the following steps: by using industrial fluorene as the raw material, sodium hydroxide as a catalyst and dimethylsulfoxide as a solvent, heating and dissolving the material in a reaction kettle, carrying out reaction kettle external circulation, passing through a microbubble generator, returning to the reaction kettle to react, cooling the reaction material to crystallize, separating, washing and recrystallizing to obtain the fluorenone. The solvent adopts a non-benzene pyridine solvent, and thus, has the advantages of low toxicity and environment friendliness. The catalyst adopts the industrial common catalyst which is cheap and accessible, thereby optimizing the production technique and greatly lowering the consumptions of the catalyst and solvent. The solvent can be recovered, thereby implementing reuse. The technique has the advantages of mild reaction conditions, simple and effective reactor, sufficient reaction, high speed and high fluorenone yield. The purity is greater than 99%, and the yield can reach 85% above.

Description

technical field [0001] The invention relates to a synthesis method of aromatic compounds, in particular to a synthesis method of 9-fluorenone. Background technique [0002] 9-fluorenone, alias benzophenone, molecular formula C 13 h 8 O, in the form of yellow orthorhombic crystals, with a melting point of 84°C and a boiling point of 341.5°C, is an important fine chemical raw material, often used as a synthetic intermediate material, and is widely used in the fields of medicine, dyestuffs, agriculture, chemicals, plastics industry and photoconductive materials. its important application. The raw material industry for the synthesis of fluorenone is also one of the important components of coal tar, accounting for 1% to 2% of the total amount of coal tar, and the price of fluorene itself is low. The higher the higher, the crude fluorene separated from coal tar can no longer meet the requirements. If it is deeply purified, the production cost will be too high, which will affect...

AI Technical Summary

Problems solved by technology

[0005] 1. Use potassium hydroxide as a catalyst, add fluorene to dimethyl sulfoxide, and obtain crude fluorenone after air oxidation or use tetrahydrofuran as a solvent and potassium hydroxide as a catalyst to produce fluorenone; the above method uses The alkali is mostly potassium hydroxide, which is expensive, and the boiling point of tetrahydrofuran is low, the recovery rate is low, and the washing process is miscible with water, and a large amount of waste water is introduced, which is difficult to handle;

[0006] 2. Use benzene-based solvent solution, sodium hydroxide as a catalyst, add quaternary ammonium salt as a phase transfer catalyst, and oxidize by blowing air at a higher temperature near the boiling point of the solution to obtain fluorenone; the disadvantage of this reaction is that it does not In the case of adding water, the quaternary ammonium salt is difficult to play the role of transfer catalyst, toluene is highly toxic, the reaction temperature is high, and the solvent loss is large;

[0008] Existing equipment for preparing fluorenone has large investment, large area occupation, complex structure of reactor, and low purity of finished product

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