Method for efficiently preparing 9-fluorenone through solid catalyst

Abstract

The invention relates to a method for efficiently preparing 9-fluorenone through a solid catalyst. The method comprises the following steps: Step 1, adding industrial fluorene, mixed solvent and solid tetramethylammonium hydroxide according to the mass ratio into a four-mouth flask; Step 2, mounting a thermometer, a heating and stirring device and a reflux condensing tube on the four-mouth flask; Step 3, starting stirring and heating at normal pressure, and introducing air for reacting; Step 4, after filtering residue, performing distillation under reduced pressure to recover solvent, and crystallizing concentrate into a fluorenone crystal; Step 5, washing and drying the fluorenone crystal to obtain a 9-fluorenone product. Compared with the prior art, the method disclosed by the invention has the benefits that firstly, the reaction temperature is low and reaction conditions are mild; secondly, due to the use of the solid catalyst, the volume yield is high and the solid catalyst is easily separated from the product; thirdly, the low-price solvent is adopted and recycled through distillation under reduced pressure, so that the cost is low; the washing water amount is low and is easily treated, so that the pollution to the environment is small; fourthly, by using the mixed solvent, the reaction yield reaches over 90 percent, the recrystallization of the reacted products is avoided, and the purity of gas chromatography is higher than 99.2 percent.

Description

technical field [0001] The invention relates to the technical field of production of aromatic compound 9-fluorenone, in particular to a method for efficiently preparing 9-fluorenone by solid catalysis. Background technique [0002] 9-Fluorenone (9-Fluorenonge), alias benzophenone, molecular formula C13H8O, yellow orthorhombic crystal, melting point 84 ° C, boiling point 341.5 ° C, is an important fine chemical raw material, is widely used in fuel, In the synthesis and preparation of photoconductive materials, medicine and luminescent materials. [0003] The method and main technology of 9-fluorenone prepared by fluorene oxidation at home and abroad are as follows: In 1996, Nippon Shokubai Co., Ltd. used Han metal vanadium, titanium and alkali metal catalysts to prepare 9-fluorenone by gas phase method, and the reaction temperature was above 400 ° C. , the yield is lower than 95% [ZL.96123084.3]. The preparation of 9-fluorenone by gas-phase oxidation of fluorene requires co...

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Problems solved by technology

A large amount of waste lye is produced in the above two inventions, which is difficult to handle and is not conducive to environmental protection, and because the use of alkaline aqueous solution as a catalyst greatly limits the feeding ratio of raw material fluorene, resulting in a low volumetric yield

[0009] The Chinese patent application number 200910187363.X (application date September 15, 2009) discloses "a method for producing 9-fluorenone", using toluene as a solvent and a quaternary ammonium salt as a catalyst to prepare 9-fluorenone. Method When the reaction temperature is 60-80°C, the purity of the product can reach 99% after one recrystallization. When the reaction temperature is 50-60°C, it needs to go through two recrystallizations to obtain the pure product, and the cost is high. Mention product yield