A preparation method of fluorenone

Abstract

The present invention relates to the field of chemical industry, and provides a method for preparing fluorenone. The method comprises the following steps: (1) extracting a fluorene oil-rich fraction from coal tar, wherein the fraction section of the fluorene oil-rich fraction is 275-295°C; (2) extracting crude fluorene oil from the fluorene oil-rich fraction, wherein the fluorene content of the crude fluorene oil is greater than 60wt%; (3) using the crude fluorene oil as a raw material, catalytically oxidizing and preparing fluorenone. After enriching the crude fluorene oil from coal tar, the present invention does not further purify the crude fluorene oil, but directly catalytically oxidizes the crude fluorene oil, directly converts the fluorene in the crude fluorene oil into fluorenone which is easier to separate, and finally obtains a fluorenone product (the purity of fluorenone is greater than 95%, and the yield is greater than 90%). The method avoids separating and purifying industrial fluorene from the fluorene-rich oil, reduces the difficulty of separating and purifying the product, shortens the process flow, and improves the added value of the product. The method has simple process, low production cost, high product added value and significant economic benefits.

Description

Technical Field

[0001] The invention relates to the field of chemical industry, and in particular to a method for preparing fluorenone. Background Art

[0002] Fluorenone is a deep-processed product of fluorene. In the prior art, fluorenone is usually prepared by using high-temperature coal tar as raw material, distilling the washing oil fraction, extracting industrial fluorene by physical separation method, and then using industrial fluorene to synthesize high value-added products of fluorenone. The process of extracting industrial fluorene includes firstly multi-stage distillation of the washing oil fraction to obtain a fluorene oil-rich fraction, then crystallizing and distilling the fluorene oil-rich fraction to obtain crude fluorene oil, and finally recrystallizing the crude fluorene oil to obtain industrial fluorene. The yield of industrial fluorene obtained by recrystallizing the crude fluorene oil is low, the product purity is low, and the cost is high.

[0003] The fluorene content in high-temperature coal tar is 1% to 2% (mass fraction). The fluorene content in medium-temperature coal tar is less than 0.5%, which is significantly lower than that in high-temperature coal tar. The crude fluorene oil obtained by treating medium-temperature coal tar with a process similar to that of extracting industrial fluorene from high-temperature coal tar has an even lower fluorene content, making it more difficult to extract industrial fluorene.

[0004] In summary, it is of great significance to provide a process for directly preparing high-purity and high-yield fluorenone using coal tar as a raw material without preparing industrial fluorene. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art that when preparing fluorenone from high-temperature coal tar as raw material, industrial fluorenone needs to be extracted first, the process of extracting industrial fluorenone is difficult to separate, the process flow is long, the cost is high, and it is not suitable for medium-temperature coal tar, thereby providing a method for preparing fluorenone.

[0006] To this end, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing fluorenone, comprising the following steps:

[0008] (1) extracting a fluorene oil-rich fraction from coal tar, wherein the fluorene oil-rich fraction has a distillation range of 275 to 295° C.;

[0009] (2) extracting crude fluorene oil from the fluorene oil-rich fraction, wherein the crude fluorene oil has a fluorene content greater than 60 wt %;

[0010] (3) Using crude fluorene oil as raw material, fluorene ketone is prepared by catalytic oxidation.

[0011] In an optional embodiment, the step (1) comprises the following steps:

[0012] (1.1) Distilling coal tar, taking the fraction between 230 and 350°C as the middle distillate;

[0013] (1.2) distilling the middle distillate oil and taking the fraction of 260-300° C. as the fluorene-containing fraction oil;

[0014] (1.3) The fluorene-containing fraction oil is distilled and the 275-295°C fraction is taken to obtain a fluorene-rich oil fraction.

[0015] Furthermore, the fluorene-rich oil fraction contains 4 to 6 wt % fluorene.

[0016] Furthermore, the conditions such as the theoretical number of plates, reflux ratio, heating rate and pressure of the distillation in steps (1.1), (1.2) and (1.3) can be determined by conventional technical means in the art, as long as the distillation fraction of the corresponding temperature is taken.

[0017] In an optional embodiment, in step (1.2), the number of theoretical plates of the distillation is 10 to 20, the reflux ratio is 5 to 20:1, the heating rate is 5 to 10°C / h, and the pressure is 10 to 100 Torr.

[0018] In an optional embodiment, in step (1.3), the number of theoretical plates of distillation is 50 to 150, the reflux ratio is 20 to 200:1, the heating rate is 2 to 5°C / h, and the pressure is 10 to 100 Torr.

[0019] In step (1.2), when taking the fraction of 260-300°C, it can be taken in sections, and the sectioning will not bring substantial impact on the final product; for example, two fractions of 260-280°C and 280-300°C are taken separately and used together as the fluorene-containing fraction oil; and then they are distilled separately in step (1.3).

[0020] In an optional embodiment, the step (2) comprises the following steps:

[0021] (2.1) crystallizing the fluorene oil-rich fraction to obtain a crystalline product;

[0022] (2.2) The crystallized product is distilled and the fraction at 285-292°C is taken to obtain crude fluorene oil.

[0023] The crude fluorene oil contains more than 60wt% fluorene.

[0024] In an optional embodiment, in step (2.1), the crystallization method is first solvent crystallization.

[0025] In an optional embodiment, the first solvent crystallization comprises the following steps: mixing the fluorene oil-rich fraction and the first solvent, heating the mixture, cooling the mixture to precipitate crystals, and performing solid-liquid separation to obtain a crystalline product.

[0026] Preferably, the heating temperature in the first solvent crystallization is 70-110° C.; after heating, the mixture is stirred evenly, and then cooled to precipitate crystals.

[0027] Preferably, the cooling in the first solvent crystallization comprises: first naturally cooling to 60-80° C., and then cooling to 30-40° C. at a cooling rate of 1-5° C. / h.

[0028] Preferably, the ratio of the mass of the fluorene oil-rich fraction in the first solvent crystallization to the volume of the first solvent is 1800-2200 g:300-500 mL.

[0029] Preferably, the first solvent is an organic solvent. Optionally, the organic solvent includes benzene series. Optionally, the benzene series includes one or more of xylene, toluene and benzene.

[0030] Preferably, the first solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is (1-2): (0-0.5): (0-0.5).

[0031] Preferably, the solid-liquid separation method is suction filtration.

[0032] In an optional embodiment, the step (3) comprises the following steps:

[0033] (3.1) catalytically oxidizing the crude fluorene oil to obtain a mixture, distilling the mixture to remove the solvent, collecting the residue, washing and drying it in sequence to obtain crude fluorene ketone;

[0034] (3.2) The crude fluorenone is crystallized to obtain fluorenone.

[0035] In the present application, crude fluorene oil is used as raw material, and the step of catalytic oxidation to prepare fluorene ketone can be carried out using conventional processes.

[0036] The purity of fluorenone is greater than 95%, and the yield is greater than 90%.

[0037] In an optional embodiment, in step (3.1), the oxygen flow rate of catalytic oxidation is 0.1 to 0.5 L / min, and the catalytic oxidation time is 1 to 5 h.

[0038] In an optional embodiment, in step (3.1), the distillation is atmospheric pressure distillation, and the drying is vacuum drying.

[0039] In an optional embodiment, in step (3.2), the crystallization is carried out by crystallization using a second solvent.

[0040] In an optional embodiment, the second solvent crystallization comprises the following steps: mixing the crude fluorenone and the second solvent, heating them, cooling them to precipitate crystals, and separating the solid from the liquid to obtain a crystalline product.

[0041] Preferably, the heating temperature in the second solvent crystallization is 70-110° C.; after heating, the mixture is stirred evenly, and then cooled to precipitate crystals.

[0042] Preferably, the cooling in the second solvent crystallization comprises: first naturally cooling to 60-80° C., and then cooling to 30-40° C. at a cooling rate of 1-5° C. / h.

[0043] Preferably, the ratio of the mass of the crude fluorenone in the second solvent crystallization to the volume of the second solvent is 1800-2200 g:300-500 mL.

[0044] Preferably, the second solvent is an organic solvent. Optionally, the organic solvent includes benzene series. Optionally, the benzene series includes one or more of xylene, toluene and benzene.

[0045] Preferably, the second solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is (1-2):(0-0.5):(0-0.5).

[0046] Preferably, the solid-liquid separation method is suction filtration.

[0047] Furthermore, after the solvent crystallization in step (2) and step (3), the decrystallization mother liquor is subjected to solvent recovery by conventional technical means in the art, the recovered solvent can be reused, and the residual liquid remaining after the solvent is recovered can be directly sent out.

[0048] The technical solution of the present invention has the following advantages:

[0049] The present invention provides a method for preparing fluorenone, comprising the following steps: (1) extracting a fluorene oil-rich fraction from coal tar, wherein the fraction range of the fluorene oil-rich fraction is 275-295°C; (2) extracting crude fluorene oil from the fluorene oil-rich fraction, wherein the fluorene content of the crude fluorene oil is greater than 60wt%; (3) using the crude fluorene oil as a raw material, catalytically oxidizing and preparing fluorenone. After enriching the crude fluorene oil from coal tar, the present invention does not further purify the crude fluorene oil, but directly catalytically oxidizes the crude fluorene oil, directly converts the fluorene in the crude fluorene oil into fluorenone which is easier to separate, and finally obtains a fluorenone product (the purity of fluorenone is greater than 95%, and the yield is greater than 90%). The method avoids separating and purifying industrial fluorene from the fluorene-rich oil, reduces the difficulty of separating and purifying the product, shortens the process flow, and improves the added value of the product. The method has simple process, low production cost, high product added value, significant economic benefits, and is applicable to medium-temperature coal tar. DETAILED DESCRIPTION

[0050] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0051] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0052] Example 1

[0053] (1) Extracting a fluorene-rich oil fraction (fraction range of 275-295°C) from medium-temperature coal tar: distilling the medium-temperature coal tar, and taking a fraction of 230-350°C as an intermediate distillate oil; adding 10 kg of the intermediate distillate oil to a real boiling point distillation kettle, distilling the oil under the conditions of 15 theoretical plates, 10:1 reflux ratio, 7°C / h heating rate, and 50 Torr, and taking a fraction of 260-300°C as a fluorene-containing fraction oil; then, using a rotary belt distillation apparatus, distilling the fluorene-containing fraction oil under the conditions of 100 theoretical plates, 100:1 reflux ratio, 3°C / h heating rate, and 50 Torr, and taking a fraction of 275-295°C as a fluorene-rich oil fraction (the fluorene-rich oil fraction contains 5 wt% fluorene);

[0054] (2) extracting crude fluorene oil (containing 67.8 wt % fluorene) from the fluorene oil-rich fraction: crystallizing the fluorene oil-rich fraction, specifically, taking 2000 g of the fluorene oil-rich fraction, mixing it with 400 mL of a first solvent (the first solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is 1.5:0.25:0.25), and heating it to 90° C., stirring it evenly, and then naturally cooling it to 70° C., and then cooling it to 35° C. at a cooling rate of 3° C. / h to precipitate crystals, and finally filtering it to obtain 250 g of a crystalline product; distilling the crystalline product using a rotary belt distiller, taking a fraction section of 285 to 292° C. as crude fluorene oil (the mass fraction of fluorene in the crude fluorene oil is greater than 60%), and the mass of the crude fluorene oil is 25 g;

[0055] (3) Using crude fluorene oil as raw material, catalytic oxidation was used to prepare fluorene ketone: the crude fluorene oil was catalytically oxidized, and the catalytic oxidation conditions were set as follows: oxygen flow rate was 0.3 L / min, and the time was 3 h; after the reaction was completed, the mixture obtained by the reaction was distilled at atmospheric pressure to remove the solvent, and the residue was collected, washed and vacuum dried in sequence to obtain crude fluorene ketone; 20 g of crude fluorene ketone was mixed with 4 mL of a second solvent (the second solvent included xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene was 1.5:0.25:0.25) and heated to 90°C, stirred evenly, and then naturally cooled to 70°C, and then cooled to 35°C at a cooling rate of 3°C / h to precipitate crystals, and finally filtered to obtain fluorene ketone.

[0056] The purity of the fluorenone obtained in this example was found to be 96.6% by gas chromatography analysis, and the yield of the fluorenone obtained in this example (mass of the fluorenone obtained / mass of the fluorenone contained in the medium-temperature coal tar) was calculated to be 91%.

[0057] Example 2

[0058] (1) Extracting a fluorene-rich oil fraction (fraction range of 275-295° C.) from medium-temperature coal tar: distilling the medium-temperature coal tar, and taking a fraction of 230-350° C. as an intermediate distillate oil; adding 10 kg of the intermediate distillate oil to a real boiling point distillation kettle, distilling the oil under the conditions of 15 theoretical plates, 15:1 reflux ratio, 8° C. / h heating rate, and 70 Torr, taking a fraction of 260-300° C. as a fluorene-containing fraction oil; then, using a rotary belt distillation apparatus, distilling the fluorene-containing fraction oil under the conditions of 120 theoretical plates, 150:1 reflux ratio, 5° C. / h heating rate, and 70 Torr, taking a fraction of 275-295° C. as a fluorene-rich oil fraction (the fluorene-rich oil fraction contains 5.5 wt % fluorene);

[0059] (2) extracting crude fluorene oil (containing 73.4 wt% fluorene) from the fluorene oil-rich fraction: crystallizing the fluorene oil-rich fraction, specifically, taking 2200 g of the fluorene oil-rich fraction, mixing it with 500 mL of a first solvent (the first solvent includes xylene and benzene, and the volume ratio of xylene to benzene is 1.5:0.5), and heating it to 100° C., stirring it evenly, and then naturally cooling it to 75° C., and then cooling it to 40° C. at a cooling rate of 4° C. / h, precipitating crystals, and finally filtering it to obtain 270 g of a crystalline product; distilling the crystalline product using a rotary belt distiller, taking a fraction section of 285 to 292° C. as crude fluorene oil (the mass fraction of fluorene in the crude fluorene oil is greater than 60%), and the mass of the crude fluorene oil is 27 g;

[0060] (3) Using crude fluorene oil as raw material, catalytic oxidation is used to prepare fluorene ketone: the crude fluorene oil is catalytically oxidized, and the catalytic oxidation conditions are set as follows: the oxygen flow rate is 0.45 L / min, and the time is 2 h; after the reaction is completed, the mixture obtained by the reaction is distilled at atmospheric pressure to remove the solvent, and the residue is collected, washed and vacuum dried in sequence to obtain crude fluorene ketone; 22 g of crude fluorene ketone is taken, mixed with 5 mL of the second solvent (the second solvent includes xylene and benzene, and the volume ratio of xylene to benzene is 1.5:0.5) and heated to 100°C, stirred evenly, and then naturally cooled to 75°C, and then cooled to 40°C at a cooling rate of 4°C / h to precipitate crystals, and finally filtered to obtain fluorene ketone.

[0061] The same method as in Example 1 was used to obtain the fluorenone obtained in this example. The purity of the fluorenone obtained was 97% and the yield was 92%.

[0062] Example 3

[0063] (1) Extracting a fluorene-rich oil fraction (fraction range of 275-295°C) from medium-temperature coal tar: distilling the medium-temperature coal tar, and taking a fraction of 230-350°C as an intermediate distillate oil; adding 10 kg of the intermediate distillate oil to a real boiling point distillation kettle, distilling the oil under the conditions of 15 theoretical plates, 8:1 reflux ratio, 5°C / h heating rate, and 35 Torr, and taking a fraction of 260-300°C as a fluorene-containing fraction oil; then, using a rotary belt distillation apparatus, distilling the fluorene-containing fraction oil under the conditions of 80 theoretical plates, 70:1 reflux ratio, 2°C / h heating rate, and 35 Torr, and taking a fraction of 275-295°C as a fluorene-rich oil fraction (the fluorene-rich oil fraction contains 4.5 wt% fluorene);

[0064] (2) extracting crude fluorene oil (containing 62.5 wt% fluorene) from the fluorene oil-rich fraction: crystallizing the fluorene oil-rich fraction, specifically, taking 1900 g of the fluorene oil-rich fraction, mixing it with 350 mL of the first solvent (the first solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is 1:0.5:0.5), heating it to 85°C, stirring it evenly, and then naturally cooling it to 60°C, and then cooling it to 30°C at a cooling rate of 2°C / h to precipitate crystals, and finally filtering it to obtain 220 g of a crystalline product; distilling the crystalline product using a rotary belt distiller, taking a fraction section of 285-292°C as crude fluorene oil (the mass fraction of fluorene in the crude fluorene oil is greater than 60%), and the mass of the crude fluorene oil is 23 g;

[0065] (3) Using crude fluorene oil as raw material, catalytic oxidation was used to prepare fluorene ketone: the crude fluorene oil was catalytically oxidized, and the catalytic oxidation conditions were set as follows: oxygen flow rate was 0.15 L / min, and the time was 4 h; after the reaction was completed, the mixture obtained by the reaction was distilled at atmospheric pressure to remove the solvent, and the residue was collected, washed and vacuum dried in sequence to obtain crude fluorene ketone; 19 g of crude fluorene ketone was mixed with 3.5 mL of the second solvent (the second solvent included xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene was 1:0.5:0.5) and heated to 85°C, stirred evenly, and then naturally cooled to 60°C, and then cooled to 30°C at a cooling rate of 2°C / h to precipitate crystals, and finally filtered to obtain fluorene ketone.

[0066] The same method as in Example 1 was used to obtain the fluorenone obtained in this example. The purity of the fluorenone obtained was 96% and the yield was 90.3%.

[0067] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing fluorenone, characterized in that: The following steps are involved: (1) extracting a fluorene oil-rich fraction from coal tar, wherein the fluorene oil-rich fraction has a distillation range of 275 to 295° C.; (2) extracting crude fluorene oil from the fluorene oil-rich fraction, wherein the crude fluorene oil has a fluorene content greater than 60 wt %; (3) Using crude fluorene oil as raw material, fluorene ketone is prepared by catalytic oxidation.

2. The method for preparing fluorenone according to claim 1, characterized in that: The step (1) comprises the following steps: (1.1) Distilling coal tar, taking the fraction between 230 and 350°C as the middle distillate; (1.2) distilling the middle distillate oil and taking the fraction of 260-300° C. as the fluorene-containing fraction oil; (1.3) The fluorene-containing fraction oil is distilled and the 275-295°C fraction is taken to obtain a fluorene-rich oil fraction.

3. The method for preparing fluorenone according to claim 1, characterized in that: The step (2) comprises the following steps: (2.1) crystallizing the fluorene oil-rich fraction to obtain a crystalline product; (2.2) The crystallized product is distilled and the fraction at 285-292°C is taken to obtain crude fluorene oil.

4. The method for preparing fluorenone according to claim 3, characterized in that: In step (2.1), the crystallization method is first solvent crystallization; Optionally, the first solvent crystallization comprises the following steps: mixing the fluorene oil-rich fraction and the first solvent, heating the mixture, cooling the mixture to precipitate crystals, and performing solid-liquid separation to obtain a crystal product; Preferably, the heating temperature in the first solvent crystallization is 70 to 110°C; Preferably, the cooling in the first solvent crystallization comprises: first naturally cooling to 60-80° C., and then cooling to 30-40° C. at a cooling rate of 1-5° C. / h; Preferably, the ratio of the mass of the fluorene oil-rich fraction in the first solvent crystallization to the volume of the first solvent is 1800-2200 g: 300-500 mL; Preferably, the first solvent is an organic solvent. Optionally, the organic solvent includes benzene series. Optionally, the benzene series includes one or more of xylene, toluene and benzene.

5. The method for preparing fluorenone according to claim 4, characterized in that: The first solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is (1-2): (0-0.5): (0-0.5).

6. The method for preparing fluorenone according to claim 1, characterized in that: The step (3) comprises the following steps: (3.1) catalytically oxidizing the crude fluorene oil to obtain a mixture, distilling the mixture to remove the solvent, collecting the residue, washing and drying it in sequence to obtain crude fluorene ketone; (3.2) The crude fluorenone is crystallized to obtain fluorenone.

7. The method for preparing fluorenone according to claim 6, characterized in that: In step (3.1), the oxygen flow rate of catalytic oxidation is 0.1 to 0.5 L / min, and the catalytic oxidation time is 1 to 5 h.

8. The method for preparing fluorenone according to claim 6, characterized in that: In step (3.2), the crystallization method is second solvent crystallization; Optionally, the second solvent crystallization comprises the following steps: mixing the crude fluorenone and the second solvent, heating the mixture, cooling the mixture to precipitate crystals, and performing solid-liquid separation to obtain a crystalline product; Preferably, the heating temperature during the crystallization of the second solvent is 70 to 110°C; Preferably, the cooling in the second solvent crystallization comprises: first naturally cooling to 60-80° C., and then cooling to 30-40° C. at a cooling rate of 1-5° C. / h.

9. The method for preparing fluorenone according to claim 8, characterized in that: The ratio of the mass of the crude fluorenone to the volume of the second solvent in the second solvent crystallization is 1800-2200 g: 300-500 mL; Preferably, the second solvent is an organic solvent. Optionally, the organic solvent includes benzene series. Optionally, the benzene series includes one or more of xylene, toluene and benzene.

10. The method for preparing fluorenone according to claim 9, characterized in that: The second solvent includes xylene, toluene and benzene, and the volume ratio of xylene, toluene and benzene is (1-2): (0-0.5): (0-0.5).