The Study On The Preparation Of Fluorenone By The Catalytic Oxidation Of Fluorene At The Eutectic Temperature

The subject selected the reaction of preparation of 9-fluorenone by the reactant fluorene, liquid phase, alkali catalytic air oxidation as research object, and optimized the phase transfer effect of phase transfer reagent and catalytic effect of alkali catalyst on the different solvent reaction system. On this basis, combined with the characteristic of the reactant fluorene and product 9-fluorenone formed the eutectic content, this paper designed the solvent-free green production preparation method of 9-fluorenone of the catalytic oxidation of fluorene. The main research results were as follows:The paper discovered eutectic phenomenon of the reactants fluorene and the product 9-fluorenone existing, measured the lowest eutectic point of reactant fluorene and product 9-fluorenoe——57.4℃, under this condition, the molar ratio of fluorene and 9-fluorenone was 0.39:0.61. The paper determined a new reaction system of the eutectic phase of the reactants fluorene and the product 9-fluorenone as organic phase, alkali liquor as the water phase, phase transfer catalytic oxidation fluorene for preparation of 9-fluorenone. Under this condition, fluorene 100% converted into 9-fluorenone. Hence, using a small amount of product fluorenone caused a lot of fluorene into fluorenone——the new reaction system was achieved. The new reaction system completely avoided the use of organic solvent.Xylene reaction system, in the condition of stirring speed of 300 r/min, the ventilation rate of 300*2 ml/min, the volume ratio of xylene solvent and aqueous solution of 5:1, KOH or NaOH aqueous solution as alkali catalyst, crown ether or polyether as the phase transfer agent, optimized the reaction conditions, investigated the influence of dosage of the phase transfer reagents and dosage of corresponding alkali catalys on the reaction, and got the best conditions of reaction conditions:reaction temperature 58℃, the alkali catalyst of 45% KOH or NaOH aqueous solution, the phase transfer reagent of 18-crown-6, the molar ratio of fluorene and 18-crown-6 of 20:1.Under the optimal reaction conditions, three different reaction system——xylene solvent saturation system, xylene solvent suspension system and isoquinoline solvent system, investigated reaction effect of different phase transfer agent. The experimental results showed that in the three systems quaternary ammonium salt, crown ether and polyether, three kinds of phase transfer agent all made fluorene completely into fluorenone. On the whole, the phase transfer effect of quaternary ammonium salt was best, because of ionic compounds of its structure; in the crown ether, the phase transfer effect of 18-crown-6 being superior to 15-crown-5 and PEG-400.Under the same phase transfer agent (18-crown-6), the paper investigated reaction effect of alkali catalyst. When the alkali catalyst was 40% KOH or 45% NaOH aqueous solution, reaction time and 9-fluorenone yield of the two were basic quite; When weak base K2CO3 catalyst was used in reaction, fluorene can’t completely convert. The results and the speculation mechanism of catalytic oxidation of fluorene for preparation of 9-fluorenone was consistent, preliminarily verified reaction mechanism.This paper designed the solvent-free,18-crown-6 as the phase transfer agent of fluorene, 9-fluorenone eutectic reaction system, conducted the eutectic temperature, higher than the eutectic temperature of a single feeding and eutectic temperature continuous feeding reaction studies. The experimental results showed that the phase transfer catalytic reaction of the fluorene and 9-fluorenone eutectic reactants for preparation of 9-fluorenone could run smoothly, and this result also from the side verified the correctness of the fluorene and 9-fluorenone eutectic point determination.