JP6052949B2 - Method for producing 9-fluorenone from fluorene - Google Patents

Description

  The present invention relates to a method for converting fluorene to 9-fluorenone by a phase transfer catalytic oxidation reaction using 9-fluorenone as a product and water as a solvent. The present invention belongs to the field of organic synthesis.

  In recent years, coal tar and related industries have been rapidly developed. Fluorene is one of the important components of coal tar, accounting for 1-2% of the weight of coal tar, and the amount of fluorene separated from coal tar is very large. Although the use of fluorene is limited, its utility value is high. Therefore, it is important to develop a downstream product of fluorene with high added value using fluorene in tar as an initial raw material. Fluorenone is a highly processed product of good tar fluorene and an important chemical industry raw material. Although many of the fluorene derivatives are synthesized from fluorenone, the demand for fluorenone in the market is large and the prospects for development of related industries are wide. Research on the synthesis of fluorenone and its application has already started from the 30s-50s of the last century, but there are few reports on manufacturers producing fluorenone on a large scale. If the conversion from industrial fluorene to fluorenone is possible, research and development on coal chemical products will inevitably be promoted and will bring better benefits to related companies.

  The reaction for producing fluorenone by oxidizing fluorene is a process in which a fluorene methylene group is oxidized to a carbonyl group. There are relatively many methods for producing fluorenone using fluorene as a raw material. Depending on the difference between the oxidizing agent used and the reaction phase, the method for producing fluorenone by oxidizing fluorene can be divided into three types: an air-gas phase oxidation method, an air-liquid phase oxidation method, and an oxidation method using other oxidizing agents. . Among them, the air vapor oxidation method belongs to a gas-solid reaction. Patent Document 1 (1999) and Patent Document 2 (2009) published a gas phase oxidation method. The reaction is carried out by passing fluorene in a gas state together with air through a solid catalyst bed layer at 380 ° C. or higher, and the reaction product is condensed and purified to obtain fluorenone. This method has the advantage that no solvent is used. However, since the reaction temperature is high and the catalyst is difficult to maintain a high conversion rate of fluorene and high selectivity to fluorenone, there is a drawback that deep oxidation of fluorene occurs.

  The air-liquid phase oxidation method uses an aprotic polar solvent such as pyridine (Patent Document 3), dimethyl sulfoxide (Patent Document 4, Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3) as a reaction solvent, and alkali metal water. In many cases, an oxide is used as a catalyst, and a phase transfer agent may be added. These methods have a fluorenone yield of 90% or more and are suitable for industrial production. However, the amount of solvent used is large and the process is complicated. In particular, the problem of solvent recovery and utilization must be considered.

  In Patent Document 5 (Application No. 200910187363.X), a method for producing fluorenone from fluorene using toluene as a solvent and a quaternary ammonium salt as a catalyst without adding an alkali was disclosed. Only quaternary ammonium salts are used as catalysts, and the conversion of fluorenone is very low.

  In Patent Document 6 (Application No. 2011103377560.2), industrial fluorene is used as a raw material, benzene-based organic matter (toluene, xylene) is used as a solvent, sodium hydroxide is used as a catalyst, air is used as an oxidant, and a quaternary ammonium salt is used. Although a method for producing fluorenone was disclosed as a phase transfer catalyst, this research does not add water, and quaternary ammonium salts are difficult to exert the action of phase transfer catalyst, and the reaction temperature is as high as 90 ° C. or higher. The solvent loss is great. Also, the study did not disclose problems such as the type of quaternary ammonium.

US Pat. No. 5,902,907 Chinese Patent Application Publication No. 10138590 U.S. Pat. No. 4,218,400 U.S. Pat. No. 3,875,237 Chinese Patent Application No. 102020543 Chinese Patent Application No. 102391087

Nishi Chemical Industries (1989, 17th page) Fuel and Chemical Industry (March 1999, page 66) Shanghai Chemical Industry (17th page, 2005)

  In the prior art, the method of producing 9-fluorenone by oxidizing fluorene with a phase transfer catalyst in the presence of an organic solvent can realize industrialization, but the presence of the organic solvent complicates the process, Productivity was relatively low. In order to solve this problem, the present invention provides a method for effectively converting fluorene to 9-fluorenone by phase transfer catalytic oxidation using 9-fluorenone as a product as a solvent. This method improved the utilization of the reactor material, eliminated the solvent separation and recovery process, realized the combined operation of the reaction solution separation and the 9-fluorenone purification step, and greatly simplified the process.

  The technical solution of the present invention is as follows.

  A method for producing 9-fluorenone from fluorene, using industrial fluorene as raw materials, 9-fluorenone and water as solvent, alkali as catalyst, quaternary ammonium salt as phase transfer agent, and oxidizing oxygen-containing gas As the agent, 9-fluorenone is produced at a reaction temperature of 70 to 83 ° C., and fluorene as a raw material is added only once or continuously replenished as the reaction proceeds.

  In the method for producing 9-fluorenone from fluorene according to the present invention, the initial charge amount or the amount of fluorene replenished each time is preferably such that the fluorene and 9-fluorenone in the reaction system form a solution. More preferably, the initial charge amount or the amount of fluorene replenished each time should be such that the molar ratio of fluorene to 9-fluorenone in the reaction system is 1-2: 1. The proportion of fluorene and 9-fluorenone is varied according to the reaction temperature. At the reaction temperature, fluorene and 9-fluorenone form a solution, and when the molar ratio of fluorene to 9-fluorenone is 1-2: 1, not only is it advantageous for carrying out the phase transfer catalytic reaction, It is advantageous to increase the speed, so that by adding a small amount of 9-fluorenone, it is realized to induce a fast conversion of a large amount of fluorene, and the reactor utilization reaches a maximum.

  The method for producing 9-fluorenone with fluorene according to the present invention further comprises the step of recovering the alkaline solution containing the quaternary ammonium salt from the reaction solution and the step of recrystallization of 9-fluorenone. After the reaction is completed, the reaction solution is mixed with the recrystallization solvent while it is hot, and the alkali solution containing quaternary ammonium is separated, recovered and recycled, and the organic layer is cooled and crystallized and filtered. To obtain purified 9-fluorenone.

  Further, the recrystallization solvent is cyclohexane.

  As a specific step, after the reaction is completed, the reaction solution is introduced into the recrystallization solvent while it is hot, or the recrystallization solvent is introduced into the hot reaction solution. Among them, the temperature after mixing the recrystallization solvent and the reaction solution can be maintained at about 70 ° C. by preheating the recrystallization solvent. Separate the alkali liquid layer containing the quaternary ammonium salt while it is hot, and use it for the next reaction to realize recycling of alkali, quaternary ammonium salt, and water as a by-product. Is cooled and crystallized, filtered and dried to obtain a successful 9-fluorenone product.

  In the method for producing 9-fluorenone from fluorene according to the present invention, as specific operation steps, fluorene and 9-fluorenone are mixed and heated to the reaction temperature so as to become an oil phase. Was added to the reactor so that the volume ratio of the oil phase to the aqueous phase was 5: 1 to 6, and the molar ratio of fluorene to the quaternary ammonium salt was 50 to 300: A quaternary ammonium salt is added so as to be 1, and an oxygen-containing gas is introduced. Among them, fluorene can be replenished in several batches according to the progress of the reaction, and the reaction is completed until the conversion of fluorene becomes 98.5%.

  Furthermore, the alkali and the quaternary ammonium salt are added only once, or added to the reaction system in a plurality of times. In the course of the reaction, the concentration of the alkaline solution should be kept at 20 to 55 wt%, preferably 30 to 40 wt%. By adding the quaternary ammonium salt in a plurality of times, it is possible to prevent the quaternary ammonium salt from being decomposed too quickly. The molar ratio of fluorene to quaternary ammonium salt is preferably 80 to 200: 1, and the volume ratio of oil phase to aqueous phase is preferably 5: 1 to 3.

The general reaction formula in the production method of the present invention is as follows.

In the general formula, R _{1 to} R ₈ are hydrogen or an inactivating group, and the inactivating group is a C _{1 to} C ₁₀ alkyl group, a C _{1 to} C ₁₀ alkoxy group, or a C _{6 to} C _10. An alkylaryl group, a C ₆ -C ₁₀ aralkyl group and a C ₁ -C ₁₀ acyl group,
Alkyl group of the C ₁ -C ₁₀ is a methyl group, an ethyl group, propyl group, butyl group, pentyl group, hexyl, heptyl, octyl, nonyl, decyl, isopropyl group, isobutyl group, isopentyl group, Selected from a cyclopentyl group, a cyclohexyl group, a methylcyclopentyl group, a dimethylcyclopentyl group and a dimethylcyclohexyl group;
Alkoxy groups of the C ₁ -C ₁₀ include a methoxy group, an ethoxy group, a propoxy group, an isobutoxy group, t-butoxy group, cyclopentyloxy group, selected from cyclohexyl group and a phenoxy group,
Alkylaryl group and aralkyl group in the C ₆ -C ₁₀ is selected from phenyl, benzyl and tolyl groups,
The C ₁ -C ₁₀ acyl group is selected from a formyl group, an acetyl group, an octanoyl group and an isovaleryl group;
The R _{1 to} R ₈ are the same or not the same.

  Furthermore, the oxygen-containing gas is first wetted by passing through warm water, and then introduced into the reactor via a gas disperser and participates in the reaction. The oxygen-containing gas is a kind selected from clean air, oxygen-enriched air, and pure oxygen. The oxygen-enriched air refers to air in which the volume fraction of hydrogen is greater than the average oxygen volume fraction in air. The oxygen-containing gas is wetted by passing it through warm water and then allowed to pass through the reaction system in order to maintain the alkali concentration in the reactor. This is because the gas is uniformly dispersed in the reaction solution.

  In the process according to the invention, different operating conditions can be employed depending on the use of different oxygen sources. For example, when pure oxygen is used as the oxygen source, oxygen can be utilized to the maximum by sealing the reactor. In addition, when air is used as an oxygen source, the organic matter carried by the reaction exhaust gas can be reduced as much as possible by performing a cooling circulation reaction under normal pressure.

  The reaction for producing 9-fluorenone from fluorene is a multiphase reaction, and stirring and gas inflow rates are important, and different agitators, stirring speeds and gas inflow rates are required for different reactors. The stirring speed is preferably 200 to 400 r / min, and the gas inflow speed is preferably 300 to 600 mL / min.

  Furthermore, the alkali as the catalyst is preferably at least one selected from oxides or hydroxides of alkali metals or alkaline earth metals. More preferably, it is at least one selected from potassium hydroxide, sodium hydroxide and lithium hydroxide.

  The phase transfer agent of the present invention is a phase transfer catalyst.

Further, the quaternary ammonium salt has a structure of the general formula R ¹ R ² R ³ R ⁴ NY,
Among them, R _{1 to} R ₄ are C _{1 to} C ₁₂ linear or branched alkyl groups, C _{5 to} C ₆ cycloalkyl groups, C _{6 to} C ₁₀ alkylaryl groups, or C _{6 to} C ₁₀ Selected from aralkyl groups, R ¹ , R ² , R ³ , R ⁴ are the same or not the same,
Wherein Y is selected from chlorine, bromine, iodine anions or hydrogen sulfate groups;
Ammonium chloride quaternary ammonium salts are: lauryltrimethylammonium chloride, biscapryldimethylammonium chloride, bisnonanedimethylammonium chloride, bisdecyldimethylammonium chloride, methyltripropylmethylammonium chloride, trioctylmethylammonium chloride, tributylmethylammonium chloride , Trinonylmethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetraoctylammonium chloride, benzyltrimethylammonium chloride, benzyltriethylammonium chloride, benzyltripropylammonium chloride, and benzyltributylammonium chloride It is a kind.

  Ammonium bromide-based quaternary ammonium salts include lauryltrimethylammonium bromide, bisoctyldimethylammonium bromide, bisnonanedimethylammonium bromide, bisdecyldimethylammonium bromide, trioctylmethylammonium bromide, trinonylmethyl bromide It is a kind selected from ammonium, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, and tetraoctylammonium bromide.

  The ammonium iodide-based quaternary ammonium salt is a kind selected from tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, and dodecyltrimethylammonium iodide.

  Ammonium hydrogen sulfate quaternary ammonium salt is tetramethylammonium hydrogensulfate, tetraethylammonium hydrogensulfate, tetrapropylammonium hydrogensulfate, tetrabutylammonium hydrogensulfate, tetradodecyltrimethylammonium hydrogensulfate, bisoctyldimethylammonium hydrogensulfate, hydrogensulfate Bisnonyldimethylammonium hydrogen, bisdecyldimethylammonium hydrogensulfate, trioctylmethylammonium hydrogensulfate, tripropylmethylammonium hydrogensulfate, tributylmethylammonium hydrogensulfate and trinonylmethylammonium hydrogensulfate are one type.

  In the method according to the present invention, the reaction is terminated when the conversion rate of the fluorene becomes ≧ 98.5%. In this reaction, it is very easy for the conversion of fluorene to reach 100%. When the conversion becomes ≧ 98.5%, convenient and reasonable conditions can be provided in the subsequent purification of 9-fluorene.

In the production method according to the present invention, the reaction process is monitored using thin layer chromatography. Thin-layer chromatography uses a silica gel G ₂₅₄ coated plate as a stationary phase, and uses a mixed solution of ethyl acetate: petroleum ether = 1: 20 as a developing agent, and performs sampling detection until fluorene as a raw material is completely reacted. The beneficial effects of the present invention are as follows.

  1. In the production method according to the present invention, 9-fluorenone as a product is replaced with a solvent, and a small amount of 9-fluorenone is used as a solvent to induce high-speed conversion of a large amount of fluorene. In addition to retaining the advantages of phase transfer catalysts, it eliminates the steps of solvent separation and recovery, and realizes the combined operation of reaction solution separation and fluorenone purification, greatly simplifying the production process of fluorenone, Realize that the reactor utilization reaches the maximum value.

  2. In the production method described in the present invention, it is not necessary to treat the recovered alkali, quaternary ammonium salt, water as a by-product, etc., and they can be directly circulated and used.

  3. In the production method described in the present invention, the conversion rate of fluorene easily reaches 100%, and the purification method of fluorenone is simplified.

  4). The manufacturing method described in the present invention is a green manufacturing method and is an environmentally friendly process, and the manufacturing operation of the present invention can realize a continuous operation.

  The following non-limiting examples will allow those skilled in the art to fully understand the present invention, but the present invention cannot be limited in any way.

  Hereinafter, the purity of industrial fluorene used in the examples is ≧ 95%.

Example 1
To a 250 mL three-necked flask, sequentially add 60.42 g of industrial fluorene, 62.87 g of 9-fluorenone, 1.00 g of tetrabutylammonium chloride, 6 g of NaOH and 9 mL of water in an 80 ° C. water bath. The three-necked flask is heated, the mechanical stirring speed is controlled at 300 r / min, air of 300 × 2 mL / min is bubbled through 80 ° C. water, and then the reaction flask is passed to start the reaction. . In the course of the reaction, while monitoring the conversion of fluorene by thin layer chromatography, after reacting for 10.5 h, the raw material point has disappeared, and then the reaction is continued for 0.5 hour, and then the reaction is stopped. While the reaction solution is hot, it is transferred to warm water and cooled. After sufficiently stirring and cooling, filtration is performed to obtain a yellow solid. The yellow solid is naturally dried in air to give 124.46 g of 9-fluorenone. According to chromatographic analysis, the content of 9-fluorenone was 97.01%, and the fluorene as a raw material was completely converted.

(Example 2)
To the 250 mL three-necked flask, 61.86 g of industrial fluorene, 30 g of 9-fluorenone and 1.20 g of tetrabutylammonium bromide were sequentially added, but the same as in Example 1. When the reaction is completed for 8 hours, the starting point disappears, and then the reaction is continued for 0.5 hour, and then the reaction is stopped. 92.86 g of crude product are obtained. According to chromatographic analysis, the content of 9-fluorenone was 96.87%, and the fluorene as a raw material was completely converted.

Example 3
61.45 g of industrial fluorene, 45.44 g of 9-fluorenone and 1.20 g of tetrabutylammonium hydrogen sulfate were sequentially added to a 250 mL three-necked flask. When the reaction was completed for 7.5 h, the raw material point disappeared, and then the reaction was continued for 0.5 hour, and then the reaction was stopped to obtain 113.19 g of a yellow crystal. According to chromatographic analysis, the content of 9-fluorenone was 96.51%, and the fluorene as a raw material was completely converted.

Example 4
To a 250 mL three-necked flask were sequentially added 15.31 g of industrial fluorene, 15.24 g of 9-fluorenone, 0.30 g of tetrabutylammonium hydrogen sulfate, 2 g of NaOH, and 3 mL of water in an 80 ° C. water bath. The three-necked flask is heated with a mechanical stirring speed of 200 r / min, air of 200 × 2 mL / min is bubbled through 80 ° C. water, and then passed through the reaction flask to start the reaction. . After reacting for 3 hours, 15.04 g of fluorene, 0.3 g of tetrabutylammonium hydrogen sulfate, 2 g of NaOH, and 3 mL of water were added and reacted for 3.5 hours. .Continue reaction for 5 hours before stopping the reaction. While the reaction solution is hot, it is transferred to warm water and cooled. After sufficiently stirring and cooling, filtration is performed to obtain a yellow solid. The yellow solid is naturally dried in air to obtain 43.28 g of yellow crystals. According to chromatographic analysis, the content of 9-fluorenone was 94.88%, and fluorene as a raw material was 1.63%.

(Example 5)
To a 250 mL three-necked flask, sequentially add 15.31 g of industrial fluorene, 15.24 g of 9-fluorenone, 2.0 g of tetrabutylammonium hydrogen sulfate, 6 g of NaOH, and 9 mL of water in a 70 ° C. water bath. The three-necked flask is heated at 200 ° C., the mechanical stirring speed is controlled to 200 r / min, and air of 200 × 2 mL / min is bubbled through 70 ° C. water, then passed into the reaction flask and reacted for 4 hours. . Thereafter, 30 g of fluorene was added and reacted for 4.5 hours, then 40.11 g of fluorene was added and reacted for 5 hours, and then the raw material point disappeared completely, and then the reaction was continued for 0.5 h. To stop. While hot, the reaction solution is transferred to warm water and allowed to cool. After sufficiently stirring and cooling, filtration is performed to obtain a yellow solid. It is air dried in air to give 100.53 g of 9-fluorenone. According to chromatographic analysis, the content of 9-fluorenone was 96.87%, and the fluorene as a raw material was completely converted.

(Example 6)
To a 250 mL three-necked flask, sequentially add 10.09 g of industrial fluorene, 10.43 g of 9-fluorenone, 3.0 g of tetrabutylammonium hydrogen sulfate, 6 g of NaOH, and 9 mL of water in a 70 ° C. water bath. Then, the three-necked flask is heated, the mechanical stirring speed is controlled to 200 r / min, air of 200 × 2 mL / min is bubbled through 70 ° C. water, and then passed into the reaction flask. When the reaction was performed for 2 h, the spot of fluorene as a raw material disappeared completely in the thin layer chromatography. Then, after adding 20 g of fluorene and reacting for 4 hours, adding 40 g of fluorene and reacting for 5.5 hours, and then adding 30.08 g of fluorene and reacting for 5 hours, the raw material point is completely disappeared, Thereafter, the reaction is continued for 0.5 h, and then the reaction is stopped. 108.79 g of 9-fluorenone was obtained, and according to chromatographic analysis, the content of 9-fluorenone was 96.47%, and the fluorene as a raw material was completely converted.

(Example 7)
To a 250 mL three-necked flask, sequentially add 40.26 g of industrial fluorene, 40.18 g of 9-fluorenone, 3.0 g of tetrabutylammonium bromide, 6 g of NaOH and 9 mL of water in a 75 ° C. water bath. The three-necked flask is heated with a mechanical stirring speed of 300 r / min, 300 x 2 mL / min air is bubbled through 75 ° C water, and then the reaction flask is passed through to start the reaction. To do. In the reaction process, while monitoring the conversion state of fluorene by thin layer chromatography, the reaction is carried out for 5.5 h and then supplemented with 40.02 g of fluorene, followed by a reaction for 6.5 h and then the reaction is stopped. While the reaction solution is hot, it is transferred to 360 ml of cyclohexane, and the temperature of the solution is kept at 65 ° C. so that 9-fluorenone is completely dissolved in cyclohexane. While hot, an alkaline aqueous layer containing 12 mL of tetrabutylammonium bromide is separated, the organic layer is cooled to 35 ° C., and 9-fluorenone is crystallized. Thereafter, extraction under reduced pressure and drying are performed to obtain 94.80 g of purified 9-fluorenone. According to chromatographic analysis, the 9-fluorenone content was 99.74%. The alkaline water layer is collected and recycled.

Claims (10)

  Using industrial fluorene as a raw material, 9-fluorenone and water as a solvent, alkali as a catalyst, quaternary ammonium salt as a phase transfer catalyst, and oxygen-containing gas as an oxidant; A step of producing 9-fluorenone at a reaction temperature, wherein fluorene as a raw material is added only once or is continuously replenished as the reaction proceeds, and 9-fluorenone from fluorene is characterized in that How to manufacture.   The fluorene as the raw material is added only once or continuously replenished as the reaction proceeds. The initial charge amount or the amount of fluorene replenished each time is determined by the solution of fluorene and 9-fluorenone in the reaction system. The method for producing 9-fluorenone from fluorene according to claim 1, wherein the amount is such that it forms.   The fluorene as the raw material is added only once or continuously replenished as the reaction proceeds, and the initial charge amount or the amount of fluorene replenished each time is the molar ratio of fluorene and 9-fluorenone in the reaction system. The method for producing 9-fluorenone from fluorene according to claim 2, wherein the amount of the fluorene is 1 to 2: 1.   The method further includes a step of combining an alkaline solution containing a quaternary ammonium salt from the reaction solution and recrystallization of 9-fluorenone, and after the reaction is completed, the reaction solution is mixed with a recrystallization solvent while hot. The alkaline liquid containing quaternary ammonium is separated, recovered and recycled, and the organic layer is cooled and crystallized, and filtered to obtain purified 9-fluorenone. A method for producing 9-fluorenone from fluorene described in 1.   The method for producing 9-fluorenone from fluorene according to claim 4, wherein the recrystallization solvent is cyclohexane.   The specific operation step is to mix fluorene and 9-fluorenone and heat to the reaction temperature so as to become an oil phase. A 20-55 wt% alkaline solution is used as the water phase, and the oil phase and the water phase are mixed. After mixing so that the volume ratio is 5: 1 to 6, the quaternary ammonium salt is added so that the molar ratio of fluorene to the quaternary ammonium salt is 50 to 300: 1. The fluorene can be replenished in a plurality of times as it is introduced, and the reaction is terminated after the reaction is carried out until the fluorene conversion rate is equal to or greater than 98.5%. A method for producing 9-fluorenone from fluorene described in 1.   The oxygen-containing gas is first wetted by passing through water, and then introduced into the reaction solution via a gas disperser and participates in the reaction. A process for producing 9-fluorenone from the described fluorene.   The said oxygen-containing gas is 1 type chosen from clean air, oxygen-enriched air, and pure oxygen, The 9-fluorenone is manufactured from the fluorene as described in any one of Claims 1-6 characterized by the above-mentioned. Method.   The fluorene to 9 according to any one of claims 1 to 6, wherein the alkali as the catalyst is at least one selected from alkali metal, alkaline earth metal oxides and hydroxides. -A method for producing fluorenone.   The addition method of the alkali and the quaternary ammonium salt is added only once, or is added in a plurality of times, and the fluorene to 9- is added according to any one of claims 1 to 6. A method for producing fluorenone.