CN105801389A - Method for preparing 9-fluorenone with fluorene - Google Patents

Abstract

The invention discloses a method for preparing 9-fluorenone from fluorene, which uses fluorene as a raw material, an alkali as a catalyst, an organic solvent containing an aromatic ring and water as a solvent, and a crown ether as a phase transfer agent to prepare 9-fluorenone , the preparation method of the present invention is to prepare industrial 9-fluorenone and high-purity 9-fluorenone by industrial fluorene and high-purity fluorene respectively. Under the conditions of the invention, the conversion rate of fluorene can reach 100%, and the selectivity of fluorenone can reach 100%; Recycling, using a high boiling point solvent to absorb the solvent in the reaction tail gas, is an energy-saving and environmentally friendly chemical synthesis process.

Description

A kind of method preparing 9-fluorenone by fluorene

technical field

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

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 substituted fluorenone derivatives, which are important chemical raw materials. Many important fluorenone derivatives are synthesized from fluorenone and its derivatives, such as bisphenol fluorenone , 9,9-bis(methoxymethyl)fluorene, etc. Therefore, fluorenone and its derivatives are in great demand in the market, and the development prospects of fine chemical products related to it are broad. As a raw material for high-end manufacturing, fluorenone requires a purity of ≥99.5%. For example, the preparation of display materials such as liquid crystals and polymer materials requires high-purity fluorenone. The composition of industrial fluorene depends on the source of coal tar. Generally, most of the impurities contained are oxides. Therefore, the purification of fluorene is much easier than that of the product fluorenone, and the residue after purification of fluorene can be directly returned to coal tar without generating secondary waste.

As early as the 1930s-1950s, research on the synthesis and application of fluorenones had been carried out, but there were few reports on the technology and manufacturers of large-scale production of fluorenones. Reports have gradually increased in recent years.

The reaction to prepare fluorenone by oxidation of fluorene is the process of oxidation of fluorenomethylene to carbonyl. The hydrogen atoms on the fluorenyl methylene group are relatively active and prone to oxidation reactions. Therefore, there are many methods for synthesizing fluorenone from fluorene as raw material. According to the oxidant used and the reaction state, etc., the method of fluorene oxidation to synthesize fluorenone can be summarized into three categories: air gas-phase oxidation method, air liquid-phase oxidation method and other oxidant oxidation methods. US5902907 (1999) and CN101385990A (2009) reported a gas phase oxidation method, in which fluorene reacts with air in a gaseous state in a solid catalyst bed above 380°C. Due to the high reaction temperature, fluorene is prone to deep oxidation and produces various by-products that are difficult to separate. Most of the air liquid-phase oxidation methods use polar aprotic solvents such as pyridine (US4218400), dimethyl sulfoxide [US3875237, Shanxi Chemical Industry (1989), Fuel and Chemical Industry (1999) and Shanghai Chemical Industry (2005)] as reaction solvents , Alkali metal hydroxide as catalyst, gas-liquid phase reaction. The solvent loss in the separation process is large, the process is complicated, and the energy consumption is large, so the recycling of the solvent needs to be considered. Using 1,3-dimethyl-2-imidazoline (DMI) as a solvent, sodium hydroxide as a catalyst, and molecular oxygen as an oxidant, reacting at a temperature higher than 40°C, fluorene is also prone to deep oxidation [Chemical Industry and Engineering (2015 )]. And chemical oxidant, such as hydrogen peroxide oxidation, the production cost of fluorenone is higher.

CN102020543A reports that toluene is used as solvent, quaternary ammonium salt is used as catalyst, and the method of preparing fluorenone by air oxidation of fluorene without adding alkali seems simple. However, only quaternary ammonium salts are used as catalysts in toluene solvent, without adding alkali, to prepare fluorenone by air oxidation of fluorene, and the conversion rate of fluorene is extremely low.

CN102391087A reports: using industrial fluorene as raw material, benzene series (toluene, xylene) as solvent, sodium hydroxide as catalyst, air as oxidant, and quaternary ammonium salt as phase transfer catalyst to prepare fluorenone. Its disadvantages are that without adding water, the quaternary ammonium salt is difficult to perform phase transfer; the reaction temperature is high, and the solvent loss is large.

Aromatic compounds (including heterocyclic aromatic compounds) can be used as solvents for the preparation of fluorenones by fluorene oxidation, and ≤C ₉ aromatics are fractions of coal tar, especially the mixture of o-xylene, m-xylene and p-xylene , The mixture of o-methylethylbenzene, m-methylethylbenzene and p-methylethylbenzene and the mixture of o-trimethylbenzene, unimaginal methylbenzene and mesitylene have few industrial uses and are difficult to separate. Using the mixture as a solvent can effectively utilize the coal tar fraction, form a coal tar industrial chain, and reduce the production cost of fluorenone. Therefore, in recent years, there are many reports on the preparation of 9-fluorenone by air oxidation of fluorene by using aromatic compounds as solvents, alkalis as catalysts, and quaternary ammonium salts as phase transfer agents. CN201310355676.8, CA2013103556274.x, CA201310355847.7, CA201410074857.8 and CN 201410074024.1 reported work in this area, and the effect is relatively good. However, at higher temperatures or for a longer period of time, the quaternary ammonium salt decomposes with high-concentration strong alkali sodium hydroxide, especially potassium oxide, and loses the function of phase transfer, making it difficult to maintain the recycling of the quaternary ammonium salt. There is a need to find phase transfer agents that are stable to high concentrations of base. In addition, from practical considerations, the above-mentioned technology uses lye and solvent to be recovered separately and refined to be recycled, and the synthesis process is long and consumes a lot of energy. Benzene and toluene with lower boiling points are used as solvents, and the solvents are entrained by the tail gas in large quantities, so the reaction is difficult to maintain and proceed effectively; when pyridine and its hydrocarbon derivatives are used as solvents, the reaction is a two-phase reaction. Therefore, reasonable reaction process conditions need to be screened.

Contents of the invention

In order to solve the deficiency that the quaternary ammonium salt decomposes under the action of high-concentration strong alkali sodium hydroxide at a higher temperature or for a longer period of time in the prior art, the present invention provides a method to replace the quaternary ammonium salt with crown ether As a phase transfer agent, a new method of catalyzing the oxidation of fluorene to prepare fluorenone. Crown ether is an ether compound, which has a completely different structure from quaternary ammonium salts. Ether is stable to strong oxidizing agents, strong reducing agents and strong alkalis. Replacing quaternary ammonium salts with crown ethers can not only retain the advantages of mild reaction conditions for phase transfer catalytic reactions, high conversion rate of fluorene, and high selectivity of fluorenones, but also directly recycle solvents, lye, and crown ethers for a long time to overcome The shortcoming that the quaternary ammonium salt of the prior art is easy to decompose and cannot be recycled for a long time is solved.

In order to solve the problems in the synthesis process of the prior art, the present invention proposes a more optimized synthesis process in terms of solvent selection, optimization of reaction conditions, and combining the advantages of crown ethers, which has significant practicality in industrial production.

Technical purpose of the present invention is achieved through the following technical solutions:

Using fluorene as raw material, alkali as catalyst, organic solvent containing aromatic ring in the molecule and water as solvent, crown ether as phase transfer agent, and oxygen-containing gas as oxidant to prepare 9-fluorenone. Specifically include the following steps:

The mixture of fluorene raw material, organic solvent containing aromatic ring in the molecule and crown ether is added to the alkali solution under stirring at 50-65°C. The present invention is not limited to the order and method of addition, as long as it is reasonable. Introduce oxygen-containing gas to react. A small amount of organic solvent entrained in the reaction tail gas is recovered by freezing or oil absorption to prevent it from polluting the environment. When the conversion rate of fluorene is ≥98.5%, after the reaction is over, cool the reaction liquid, crystallize the fluorenone, filter the reaction mixture to obtain 9-fluorenone crystals and filtrate, and the filtrate is directly used for the next reaction, and the 9-fluorenone crystals are simply washed , Dry to become a product.

The fluorene raw material is crude fluorene and high-purity fluorene with refined purity ≥ 99.5% of crude fluorene;

The fluorene raw materials also include various substituted fluorenes;

Described alkali is the hydroxide of alkali metal, the carbonate of alkali metal and the bicarbonate of alkali metal in the periodic table;

The organic solvent containing an aromatic ring in the molecule is selected from one of aromatic hydrocarbons, nitrogen heterocyclic compounds and 9-fluorenones with a boiling point ≥ 138 ° C and ≤ _C9 ;

The structural general formula of described crown ether is Where n is an integer of ₄ or more; the R2 and _R3 connected to the adjacent carbon atoms of the crown ether are the same or different, and are respectively selected from hydrogen or C _1-10 straight-chain hydrocarbon groups, branched-chain hydrocarbon groups, and cycloalkyl hydrocarbon groups , hydrocarbyl cycloalkyl, hydrocarbyl aryl, aryl hydrocarbyl, or R ₂ and R ₃ form a cyclohexane ring structure and a crown ether ring to form a fused ring structure, or R ₂ and R ₃ form a benzene ring structure and a crown ether ring to form a Fused ring structure. As the value of n increases, the same crown ether can form multiple cyclohexane ring structures and crown ether rings to form a fused ring structure, and multiple benzene ring structures and crown ether rings to form a fused ring structure.

The added amount of the fluorene raw material is to form a solution, a saturated solution or a suspension of fluorene with an organic solvent;

The oxygen-containing gas is selected from clean air, oxygen-enriched air and oxygen, and enters the reaction system through a gas disperser;

The molar ratio of the fluorene raw material to the crown ether is 5-200:1;

The concentration of the alkaline solution is 25% to 55%;

The volume ratio of the organic solvent to the alkali solution is 1:0.3 to 1.5;

The oxygen-containing gas is a moist gas, and in order to ensure rapid and complete transformation of fluorene into fluorenone, oxygen is in excess.

The reaction temperature of the present invention can be selected in a wide range, such as the reaction can be carried out smoothly at 10-100 ° C, but from the perspectives of practical applicability and energy saving, it is generally better to react at 50-65 ° C;

The fluorene raw material used in the present invention is divided into two kinds of specifications, one is industrial (crude) fluorene, its purity ≥ 95%, can be directly converted into fluorenone with a purity ≥ 95%, for general industrial use. The second type is high-purity fluorene, which is obtained by refining crude fluorene with a purity of ≥95% to high-purity fluorene with a purity of ≥99.5%, which can be directly converted into high-purity fluorenone with a purity of ≥99.5% for high-end manufacturing raw material. Such as manufacturing display materials, luminescent materials, etc.

The outstanding advantage of the present invention is that under the characteristic reaction conditions of the present invention, the reaction of converting fluorene into 9-fluorenone is a high-atom-economical reaction, and fluorene can be quantitatively converted to 100% of 9-fluorenone, and the impurities in fluorene No change occurs.

Most impurities in industrial fluorene are oxygen-containing compounds, and its structure is close to that of fluorenone. Refining and purifying fluorene is easier than refining and purifying fluorenone, and does not generate secondary waste. Therefore, when preparing high-purity fluorenone, it is reasonable to choose high-purity fluorene as raw material.

High-purity fluorene is a high-purity fluorene with a purity ≥ 99.5% obtained from industrial fluorene through recrystallization from industrial ethanol, ethanol, propanol, butanol, toluene, xylene, cyclohexane and other solvents or their mixtures.

The fluorene raw materials used in the present invention are not limited to industrial (crude) fluorene and high-purity fluorene, but also include various substituted fluorenes, see the following reaction formula for details.

The solvent of the present invention is an organic solvent containing an aromatic ring in the molecule, and is selected from at least one of aromatic hydrocarbons with a boiling point of ≥138° C.≤C9, nitrogen heterocyclic compounds and the product ₉ -fluorenone.

The aromatic hydrocarbon solvent of _≤C9 with a boiling point≥138°C is selected from o-xylene, m-xylene, p-xylene, o-methylethylbenzene, m-methylethylbenzene, p-methylethylbenzene, o-trimethylbenzene, A mixture of one or more of mesitylene, mesitylene, propylbenzene and cumene. Preference is given to mixed xylenes, mixed methylethylbenzenes or mixed mesitylenes as solvents. For solvents with lower boiling points such as benzene and toluene, as the reaction progresses, a large amount of solvent is entrained out of the system by the reaction tail gas, which changes the oil-water ratio of the reaction system, deteriorates the reaction effect, and pollutes the environment.

The nitrogen heterocyclic compound is used as a solvent, and is selected from one or a mixture of quinoline, hydrocarbyl derivatives of quinoline, isoquinoline and hydrocarbyl derivatives of isoquinoline. Preferably quinoline and isoquinoline are used as solvents. Pyridine with a low boiling point and hydrocarbon derivatives of pyridine are used as solvents. On the one hand, they are miscible with water, and on the other hand, they are carried out of the system by reaction tail gas, which deteriorates the reaction effect and pollutes the environment.

When the product 9-fluorenone is used as a solvent, the structure of the selected 9-fluorenone is consistent with the structure of the fluorenone raw material; the purity of the 9-fluorenone is consistent with the purity of fluorene; the procedure for separating and refining fluorenone can be simplified, and the Realize the lowest cost of fluorenone production.

The bases used in the present invention are hydroxides, carbonates and bicarbonates of alkali metals in the periodic table. The alkali metals therein are commonly used alkali metals such as lithium, sodium and potassium.

The crown ether used in the present invention has the general formula The crown ether, the integer of n=4～10. For example, crown ethers 12-crown-4, 15-crown-5, 18-crown-6, 21-crown-7, 24-crown-8, 27-crown-9, 30-crown-10, etc. _The R2 and _R3 connected to the adjacent carbon atoms of the crown ether are the same or different, and are respectively hydrogen or C _1-10 straight-chain hydrocarbon groups, branched-chain hydrocarbon groups, cycloalkyl hydrocarbon groups, hydrocarbon cycloalkyl groups, hydrocarbon aromatic groups base, aryl hydrocarbon group, or R ₂ and R ₃ form a cyclohexane ring structure and a crown ether ring to form a condensed ring structure, such as cyclohexane and crown ether, cyclohexane and 18-crown-6, dicyclohexyl and 18-crown-6, etc., or R ₂ and R ₃ form an aromatic ring and a crown ether ring to form a condensed aromatic ring structure, such as benzo crown ether, benzo 18-crown-6, dibenzo 18-crown-6, etc. In cyclohexane crown ether, at least one cyclohexane is fused with crown ether, and in benzo crown ether, at least one benzene ring is fused with crown ether.

The addition amount of the fluorene raw material in the present invention can form a fluorene solution, a fluorene saturated solution or a fluorene suspension with corresponding solvents, depending on the required reaction rate and also determines the utilization rate of the reaction equipment. Generally speaking, the mass transfer and heat transfer rate of the solution is better, and the equipment utilization rate of the suspension is high.

The ratio of other materials is generally: the molar ratio of fluorene to crown ether is 5-200:1; the concentration of alkali solution is 25-55wt%; the volume ratio of organic solvent to alkali solution is 1:0.3-1.5. Under such conditions, the comprehensive effect of the reaction is better.

The oxidizing agent of the present invention is a gas containing molecular oxygen, which can be clean air, oxygen-enriched air or oxygen. Molecular oxygen-containing gas is wetted by water vapor at the same reaction temperature before entering the reactor, and the wet oxygen-containing gas enters the reactor through a gas disperser. A sufficiently high aeration rate has the function of a stirrer, and the gas disperser has a It is conducive to the high dispersion of oxygen and the mass transfer and heat transfer of gas-liquid-liquid phase medium. The preferred gas feeding rate is 300-600ml/min. The gas diffuser is fired from a microporous glass sandboard.

When oxygen is used as the oxidant, the reactor is sealed, and the oxygen is in a slight excess, generally no more than 1%. Otherwise, side effects may occur.

Stirring rate is very important for phase transfer catalytic reaction. Sufficient stirring rate ensures that the gas-liquid-liquid phase medium is fully mixed and evenly contacted to ensure good mass and heat transfer. The preferred stirring rate is 200-400 revolutions/min.

The adaptable temperature of this reaction is very wide, all can be in 0～100 ℃. The reaction temperature depends on other conditions. The reaction temperature determines the energy consumption and the reaction time, which should be determined comprehensively. Generally, it is 50-65°C. When 9-fluorenone is used as solvent, the reaction temperature is 58-60°C.

A small amount of solvent entrained in the reaction tail gas is recovered by freezing or oil absorption, reducing the pollution of the solvent to the environment. For example, the solvent with high boiling point can be recovered by freezing, and the xylene in the tail gas can be recovered by using high-boiling α-methylnaphthalene to absorb other agents. There are no strict restrictions on the two methods. When 9-fluorenone is used as a solvent, there is no fluorenone entrainment in the tail gas, so the problem of solvent recovery can be ignored and the process can be simplified. When oxygen is used as the oxidant, there is no oxidation tail gas.

Under the conditions selected in the present invention, the conversion rate of fluorene can reach or easily reach 100%. The conversion rate of fluorene reaches ≥98.5%, the reaction time is short, and the reaction solution is cooled, crystallized, filtered and other simple post-processing processes to obtain 9-fluorenone crystals and filtrate, and the filtrate is directly recycled. Fluorenone crystals do not contain fluorene.

The present invention uses the product 9-fluorenone as a solvent, and the structure of the selected 9-fluorenone is consistent with that of fluorene; the purity of the 9-fluorenone is consistent with that of fluorene, so as to simplify the separation process.

When the product 9-fluorenone is used as a solvent, the reaction temperature is 58-83°C. The selected reaction temperature is 58-60°C, which is determined by the lowest eutectic point of fluorenone and fluorene and the operation stability, and energy is wasted if it is higher than 60°C. When the reaction temperature is 58°C, add a small amount of mixture of fluorenone and fluorene as the reactant to ensure that a thin organic solution layer is formed on the surface of the water layer at the reaction temperature. With the transformation of fluorene, add it once, multiple times or continuously Fluorene, keep the fluorene and 9-fluorenone in the reaction mixture as a solution or suspension of fluorene, stop the reaction after the conversion rate of fluorene reaches the requirement, introduce the reaction solution into a hot organic solvent to mix and dissolve, separate and dissolve the dissolved fluorene while hot The mixture and the water layer are used for the next cycle reaction, and the oil layer is cooled and filtered to obtain 9-fluorenone crystals. After simple washing and drying, the product fluorenone is obtained, and the filtrate organic solution is retained for recycling. The molar ratio of fluorenone and fluorene in the mixture of fluorenone and fluorene is 61:39.

When 9-fluorenone is a solvent, the reaction solution is introduced into a hot organic solvent, or the hot solvent is introduced into the reaction solution, and the solvent is ≤ C ₉ aromatic hydrocarbon solvent, selected from benzene, toluene, o-xylene, m-xylene, p-xylene One or more mixtures of toluene. Mixed xylenes are preferred as solvents. In addition, at least one of cyclohexane, cycloheptane, hexane and heptane can also be selected; cyclohexane is preferred.

The preparation method of the present invention is also applicable to the preparation of derivatives of fluorenone in the following general reaction formula:

In the general formula, R ₁ -R ₈ are the same or different, and are selected from hydrogen, halogen atoms or inert substituents, and the inert substituents are substituents that do not react under the reaction conditions, and are selected from C ₁ to C ₁₀ alkyl, C ₁ -C ₁₀ alkoxy, C ₆ -C ₁₀ alkaryl, C ₆ -C ₁₀ aralkyl, C ₁ -C ₁₀ acyl, nitro and carboxyl;

The C ₁ -C ₁₀ alkyl group is selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, isobutyl, iso Pentyl, cyclopentyl, cyclohexyl, methylcyclopentyl, dimethylcyclopentyl and dimethylcyclohexyl;

The C ₁ -C ₁₀ alkoxy group is selected from methoxy, ethoxy, propoxy, isobutoxy, tert-butoxy, cyclopentyloxy, cyclohexyloxy and phenoxy;

The C ₆ -C ₁₀ alkaryl group and C ₆ -C ₁₀ aralkyl group are selected from phenyl, benzyl and tolyl;

The C ₁ -C ₁₀ acyl group is selected from formyl, acetyl, octanoyl and isovaleryl;

Under the conditions of the present invention, the progress of the reaction is preferably monitored by thin layer chromatography. For thin-layer chromatography, silica gel G254 was used as the stationary phase, and a mixed solution of ethyl acetate:petroleum ether=1:20 (volume ratio) was used as the developing solvent. Track the reaction with thin-layer chromatography, and detect the conversion of fluorene by sampling until the spots of fluorene disappear, then continue the reaction for 1-2 hours, and stop the reaction.

The beneficial effects of the present invention are:

① According to the preparation method of the present invention, 9-fluorenones with different structures and different purity specifications can be used to produce 9-fluorenone with corresponding structures and corresponding purity specifications according to the application.

Under the conditions of the present invention, the reaction is a high atom economy reaction, only a small amount of water is a by-product, 100% of fluorene can be converted into 9-fluorenone, and impurities in fluorene do not participate in the reaction. Air is the cheapest oxidant, and it is easy to separate. The obtained reaction liquid can be obtained through simple operations such as cooling, crystallization, filtration and washing to obtain the product fluorenone, without further purification of the product, and the filtrate can be directly recycled. The synthesis process is simple. The present invention is Green synthesis method.

② According to the preparation method of the present invention, under suitable conditions, the conversion rate of high-purity fluorenone can reach 100%, and fluorenone with a purity of 100% can be obtained, which meets the needs of high-end manufacturing for high-purity fluorenone.

③ In the preparation method of the present invention, fluorene can be reacted in a solvent in a suspended state, which improves the utilization efficiency of the reactor.

4. The preparation method of the present invention has mild reaction conditions. After the reaction liquid is cooled and the crystal fluorenone is separated, the filtrate containing solvent, alkali, crown ether and unreacted fluorene raw material and even by-product water is directly recycled. The boiling point oil absorbs the solvent entrained in the tail gas of the reaction, which is an energy-saving and environmentally friendly green synthesis process.

⑤ When 9-fluorenone is used as a solvent, a continuous production process can be realized, and the process of absorbing the solvent from the reaction tail gas with high boiling point oil can be omitted.

detailed description

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

Example 1

Add 42.00g of industrial fluorene with a mass fraction of 95.44%, 3.20g of 18-crown-6, 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 tail gas entrainment. Solvent, 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 300ml x 2/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 the crystal fluorenone with a small amount of water, and place the crystal in the air to dry naturally. Weighing 32.42g, its purity was 100% by gas chromatography analysis. The alpha-methylnaphthalene absorbent gained weight and had water beads present.

Example 2

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.

Example 3

According to the procedure of Example 1, 45 ml of xylene, 62.62 g of industrial fluorene, 4.80 g of 18-crown-6, 10.0 ml of 45 wt% KOH solution were added, and the temperature of the water bath was 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.

Example 4

Add 30g of isoquinoline, 40g of industrial fluorene, 3.2g of 18-crown-6 and 9ml of 45wt% KOH solution into a four-neck flask, the temperature of the water bath is 58°C, and the reaction is carried out according to Example 1. After 5 hours of reaction, thin-layer chromatography It showed that the spots of the fluorene raw material disappeared, and the reaction was stopped after continuing the reaction for 1 h. 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. .

Example 5

Except replacing 4.80g 18-crown-6 with 3.96g of 15-crown-5, and 45% NaOH solution instead of 45wt% KOH solution, other conditions were the same as in Example 3. After 23 hours of reaction, TLC showed fluorene raw material spots Disappeared, continue to react for 2h and then stop the reaction. 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 48.55g, its purity was 100% by gas chromatography analysis.

Example 6

According to the procedure of Example 1, 17.64 g of pure fluorenone, 10.78 g of industrial fluorene, 0.82 g of 18-crown-6, and 6 ml of 45 wt % KOH solution were added to the four-necked flask, and the temperature of the water bath was kept at 58 ° C. After reacting for 4 hours, TLC showed that the spots of the fluorene raw material disappeared, and the reaction was stopped after continuing the reaction for 1 hour. Chromatographic analysis showed that fluorene was completely converted, and only one peak of fluorenone was increased. The reaction solution is introduced into hot cyclohexane to dissolve, the water layer is separated for recycling in the next reaction, the oil layer is cooled, the fluorenone crystallizes, the mixture is filtered, the filtrate is recovered for later use, the crystal fluorenone is washed with a small amount of water, and placed in the air to dry naturally crystals. Weighing 21.68g, its purity by gas chromatography analysis is 100%.

Example 7

At a water bath temperature of 75°C, dissolve 20g of industrial fluorene with a purity ≥ 95% in 180mL of industrial ethanol, cool to 35°C while stirring, the fluorene crystallizes, filter under reduced pressure, wash the filter cake, and dry the filter cake naturally at room temperature to obtain 13.0 g of refined fluorene, the purity of fluorene by gas phase analysis was 100%.

Replace 10.78g of industrial fluorene in Example 6 with 10.28g of the above-mentioned refined fluorene. Others are the same as in Example 6. After 4 hours of reaction, TLC shows that the spots of fluorene raw material disappear, and stop the reaction after continuing the reaction for 1 hour. Chromatographic analysis of the reaction solution showed only one peak of fluorenone. 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 air to dry naturally to obtain 27 g of pure fluorenone.

Example 8

According to the procedure of Example 5, 17.64 g of pure fluorenone, 10.78 g of industrial fluorene, 0.82 g of 18-crown-6, 4.58 g of KOH, and 6 ml of water were added into a four-necked flask. After reacting for 5 hours, the fluorene raw material spots nearly disappeared. Add 25.00g of industrial fluorene, continue the reaction for 11 hours, add 1.00g of 18-crown-6, and continue the reaction for 11 hours. , only fluorenone is generated, and the peak numbers of other components remain unchanged. After the reaction was completed, the reaction liquid was dissolved in hot toluene, the water layer was separated and recovered, the toluene layer was cooled, the fluorenone crystallized, the toluene was filtered by suction and recovered for use, the fluorenone crystals were washed with a small amount of water, and dried in air to obtain 39.82 g of pure fluorenone.

Example 9

According to the program of Example 1, the xylene of 45ml, 42.00g industrial fluorene, 3.2g 18-crown-6, 7.3g K ₂ CO ₃ and 9ml water are packed into four-necked flask, stirring speed 300 rev/min, water bath temperature At 58°C, clean air was introduced at 300*2ml/min, and after 21 hours of reaction, thin-layer chromatography showed that the spots of fluorene raw materials disappeared.

Example 10

According to the procedure of Example 1, 45ml of xylene, 42.00g of industrial fluorene, 3.2g of 18-crown-6, 7.3g of NaOH and 9ml of water were loaded into a four-necked flask, the stirring rate was 300 rpm, and the temperature of the water bath was 58°C. Pass clean air at 300*2ml/min, react for 21 hours, thin-layer chromatography shows that the spot of fluorene raw material disappears.

Example 11

According to the procedure of Example 1, 45ml of xylene, 42.00g of industrial fluorene, 2.62g of 15-crown-5, 7.4g of KOH and 9ml of water were loaded into a four-necked flask with a stirring rate of 300 rpm and a water bath temperature of 58°C. Pass clean air at 300*2ml/min, react for 7.5 hours, thin-layer chromatography shows that the spots of fluorene raw materials disappear.

Example 12

According to the procedure of Example 1, 50ml of xylene, 40.03g of industrial fluorene, 8.11g of 18-crown-6, 24ml of 40wt% KOH solution were added to the four-neck flask, and after 7 hours of reaction, thin-layer chromatography showed that the spots of the fluorene raw material disappeared , Stop the reaction after continuing the reaction for 1 h. Cool the reaction solution, crystallize the fluorenone, filter the mixture, recover the filtrate for use, wash the crystal fluorenone with a small amount of water, place it in the air to dry naturally, weigh 23.94g, and its purity is 100% by gas chromatography analysis.

Replace 50ml of xylene, 8.11g of 18-crown-6 and 24ml of 40% KOH solution with the separated filtrate, add 40g of industrial fluorene to repeat the above experiment, after 10 hours of reaction, TLC shows that the spots of fluorene raw material disappear, and continue the reaction for 1 hour After stopping the reaction. 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 it in the air to dry naturally. Weighing crystal 38.82g, its purity is 100% by gas chromatography analysis.

Claims (9)

1. the method being prepared 9-Fluorenone by fluorenes, it is characterised in that specifically include following steps:

Fluorenes raw material, molecule will contain organic solvent and the crown ether mixing of aromatic ring, under stirring at 50～65 DEG C, add aqueous slkali, logical Enter oxygen-containing gas in reactant liquor, reclaim, by freezing or oily absorption pattern, a small amount of organic solvent that reaction end gas is carried secretly, to fluorenes Conversion ratio >=98.5% terminate reaction, cool down reactant liquor, 9-Fluorenone crystallize, filter reactant mixture, obtain 9-Fluorenone crystal and Filtrate, filtrate is directly used in be reacted next time, and 9-Fluorenone crystal to obtain product through simply washing, being dried；

Described fluorenes raw material is selected from thick fluorenes and derivant thereof or the high-purity fluorenes through refined purity >=99.5 and derivant thereof；

Described alkali is alkali-metal hydroxide, alkali-metal carbonate or alkali-metal bicarbonate in periodic chart；

In described molecule containing aromatic ring organic machine solvent selected from boiling point >=138 DEG C≤C₉Aromatic hydrocarbon, nitrogen heterocyclic and 9- One in Fluorenone；

The general structure of described crown ether isThe wherein integer of n >=4；R₂And R₃Separately select From hydrogen atom or C_1～10Straight chained alkyl, branched alkyl, cycloalkyl-alkyl, alkyl-cycloalkyl, alkylaryl or aryl alkyl；Or R₂And R₃Form cyclohexane ring structure；Or R₂And R₃Form aromatic ring structure, described cyclohexane ring structure, aromatic ring structure and crown ether cycle Form one or more condensed ring structure；

The addition of described fluorenes raw material is to form the solution of fluorenes, saturated solution or suspension with organic solvent；

Described oxygen-containing gas selects the one in air, oxygen-enriched air, oxygen, enters reactant by gas distributor System；

Fluorenes raw material is 5～200:1 with the mol ratio of crown ether；

The concentration of described aqueous slkali is 25～55wt%；

Described organic solvent is 1:0.3～1.5 with the volume ratio of aqueous slkali；

Described oxygen-containing gas is the oxygen-containing gas of clean moistening, and oxygen is excessive.

Preparation method the most according to claim 1, it is characterised in that: thick fluorenes is purity >=95%；High-purity fluorenes is by slightly In industrial alcohol, ethanol, propanol, butanol, benzene,toluene,xylene, hexamethylene equal solvent, at least one makees solvent and heavily ties fluorenes The high-purity fluorenes of purity >=99.5% that crystalline substance obtains.

Preparation method the most according to claim 1, it is characterised in that: alkali metal is lithium, sodium and potassium.

Method the most according to claim 1, it is characterised in that: 4≤n≤10 in crown ether formula.

Preparation method the most according to claim 1, it is characterised in that: described organic solvent selected from boiling point >=138 DEG C≤C₉ Aromatic hydrocarbon, selected from o-Dimethylbenzene, meta-xylene, xylol, adjacent methyl-ethyl benzene, a methyl-ethyl benzene, to methyl-ethyl benzene, adjacent three At least one in toluene, pseudocumene, sym-trimethylbenzene., propylbenzene and cumene；Or selected from quinoline, the hydrocarbyl derivative of quinoline At least one in the alkyl derivative of thing, isoquinolin and isoquinolin；Or the product 9-Fluorenone that fluorenes raw material is corresponding.

Preparation method the most according to claim 1, it is characterised in that: described oxygen-containing gas selects self-cleaning air, oxygen-enriched Air and purity oxygen in one；When selecting purity oxygen, use closed reactor, and oxygen is micro-excess.

7. according to the preparation method described in claim 1 and 5, it is characterised in that: when with product 9-Fluorenone for solvent, reaction temperature Degree is 58～60 DEG C, is initially charged a small amount of Fluorenone and the mixture that fluorenes mol ratio is 61:39 reacts, along with the conversion of fluorenes, Once, repeatedly or be continuously added to fluorenes, keep reactant mixture be fluorenes be solution or the suspension in fluorenes with 9-Fluorenone, the conversion of fluorenes After rate reaches requirement, stopped reaction, reaction liquid imports the organic solvent of heat, and separating reaction mixture, under recovery water layer is used for Secondary response, oil reservoir cooled and filtered obtains 9-Fluorenone crystal, through simply washing, be dried to obtain product Fluorenone；Reclaim filtrate to have Machine solution retains use next time.

8. according to the preparation method described in claim 1,5 and 7, it is characterised in that: reactant liquor is imported organic solvent, described in have Machine solvent described in the claim 5 boiling point >=138 DEG C≤C₉Aromatic hydrocarbon and benzene, toluene, hexamethylene, cycloheptane, At least one solvent in hexane, heptane.

Preparation method the most according to claim 1, it is characterised in that: described thick fluorene derivative or high-purity fluorene derivative are fluorenes The derivant that on aromatic ring, hydrogen is replaced, alkyl substituted fluorene, alkoxyl substituted fluorene, acyl group substituted fluorene, halogen atom substituted fluorene, hydroxyl take For fluorenes or carboxyl substituted fluorene.