A production method of 1,2-benzanthracene

Abstract

The present invention relates to a production method of 1,2-benzanthracene, which uses the dianthracene oil fraction in coal tar as raw material. First, a 1,2-benzanthracene narrow fraction of 45% - 55% is obtained by vacuum distillation. Then, medium wash oil is used as a solvent to crystallize the narrow fraction to obtain crude 1,2-benzanthracene with a content of 80% - 85%. The crude 1,2-benzanthracene is sublimated to obtain sublimated 1,2-benzanthracene with a content of 93% - 95%. Finally, methanol washing is carried out to obtain refined 1,2-benzanthracene with a content greater than 98%. The production method of the present invention is a physical extraction method. Different from the synthesis method, there is no chemical reaction, which not only recovers the valuable 1,2-benzanthracene resource in coal tar, but also can avoid the complex operation and environmental pollution of the synthesis method.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a method for separating and refining 1,2-benz[a]anthracene from coal tar. Background Art

[0002] 1,2-Benz[a]anthracene, also known as benz[a]anthracene, has the structural formula , and exists in the distillate fraction of dianthracene oil in coal tar. Derivatives synthesized from 1,2-benz[a]anthracene as an intermediate are widely used in the synthesis of materials with conjugated structures and have extensive applications in fields such as field-effect transistors and organic light-emitting diodes. Since it is harmful to the environment and water bodies, it can also be used for environmental monitoring.

[0003] Currently, the production methods of 1,2-benz[a]anthracene are all synthetic methods. Using 1-bromonaphthalene as a raw material or naphthalene as a raw material, through Friedel-Crafts acylation reaction, dehydration and ring closure with strong acid, and finally hydrogenation reduction to obtain the product 1,2-benz[a]anthracene. Patent CN112979402A discloses an industrial production method of benz[a]anthracene. Using 2-bromonaphthalene as a raw material, through a series of reactions such as lithiation, borylation, acidification, Suzuki reaction, Weinreb reaction, Wittig reaction and ring closure to obtain benz[a]anthracene. The synthetic method has relatively complex reactions, many reaction steps, many by-products, serious environmental problems, and high production costs.

[0004] The distillate fraction of dianthracene oil accounts for 8% - 10% of coal tar, with a large quantity and wide sources. The distillate fraction of dianthracene oil contains 3.9% of 1,2-benz[a]anthracene ("Coal Tar Chemistry", 2nd Edition, edited by Xiao Ruihua, Metallurgical Industry Press, 2014, Table 8-2 Anthracene Oil Composition on Page 209). In the process of producing fluoranthene and pyrene by distillation method, further distillation can obtain a narrow fraction of 1,2-benz[a]anthracene, and further produce refined 1,2-benz[a]anthracene with a mass fraction greater than 98%. Extracting 1,2-benz[a]anthracene from the distillate fraction of dianthracene oil in coal tar not only recovers valuable resources but also avoids the complex operations and environmental pollution of the synthetic method. Summary of the Invention

[0005] The purpose of the present invention is to provide a production method of 1,2-benz[a]anthracene, which is a method for purifying 1,2-benz[a]anthracene from the distillate fraction of dianthracene oil in coal tar. Using the distillate fraction of dianthracene oil as a raw material, through unit operations such as vacuum distillation, crystallization, sublimation and solvent washing to produce 1,2-benz[a]anthracene. Different from the synthetic method, there is no chemical reaction, which not only recovers the valuable 1,2-benz[a]anthracene resource in coal tar but also avoids the complex operations and environmental pollution of the synthetic method.

[0006] The technical solution of the present invention consists of the following steps, and the process flow block diagram is shown in Figure 1 :

[0007] Step 1: Add dianthracene oil into a vacuum distillation device, and perform vacuum distillation to obtain a 1,2-benz[a]anthracene narrow fraction with a mass fraction of 1,2-benz[a]anthracene of 45% - 55%;

[0008] Step 2: Heat the 1,2-benz[a]anthracene narrow fraction obtained in Step 1 to 200 °C, and then add it to a crystallizer with stirring together with medium wash oil at a mass ratio of narrow fraction:medium wash oil = 1:0.5. Control the stirring speed at 15 r / min - 20 r / min, and then reduce the temperature of the material to 30 °C - 40 °C at a cooling rate of 5 °C - 10 °C / h. After centrifugal separation, crude 1,2-benz[a]anthracene with a content of 80% - 85% is obtained. The medium wash oil in the centrifugal filtrate does not need to be recovered and can be directly used for benzene washing;

[0009] Step 3: Add the crude 1,2-benz[a]anthracene obtained in Step 2 into a sublimation kettle, control the vacuum degree in the sublimation kettle at -0.08 MPa - -0.09 MPa, and control the sublimation temperature at 150 °C - 160 °C to obtain sublimated 1,2-benz[a]anthracene with a content of 93% - 95%;

[0010] Step 4: Add the sublimated 1,2-benz[a]anthracene obtained in Step 3 and methanol at a mass ratio of 1:1 into a crystallizer, heat up to the boiling point of methanol, keep it at a constant temperature for 30 min, then cool it down to 20 °C - 30 °C by passing cooling water, and perform centrifugal filtration and drying to obtain refined 1,2-benz[a]anthracene with a content greater than 98%. The filtrate is subjected to vacuum distillation to recover the methanol solvent for recycling.

[0011] The distillation column in the vacuum distillation device described in Step 1 is a packed column, and the intermittent distillation method is adopted. The vacuum degree at the top of the column is -0.08 MPa - -0.09 MPa, the reflux ratio is 20 - 30, and the number of theoretical plates is 80 - 100.

[0012] The crystallization solvent in Step 2 is medium wash oil, which is a part of the wash oil fraction in coal tar, with a boiling range of 250 °C - 270 °C, a flash point greater than 100 °C, safe operation, no volatilization, no environmental problems, and the medium wash oil can still be used for benzene washing after use without affecting the benzene washing effect, reducing the trouble of recovery.

[0013] 1,2-Benz[a]anthracene is easy to sublimate. By controlling the vacuum degree and sublimation temperature, it is further purified, and finally refined 1,2-benz[a]anthracene with a mass fraction greater than 98% is obtained through washing and crystallization with methanol solvent.

[0014] The present invention adopts four unit operations of vacuum distillation, crystallization, sublimation, and solvent washing, and finally separates and refines refined 1,2-benz[a]anthracene from the dianthracene oil fraction of coal tar. The production process is safe and environmentally friendly, avoiding the complex operations and environmental pollution of the synthesis method. Description of the Drawings

[0015] Figure 1Process flow diagram of the present invention. Specific embodiments

[0016] The present invention will be further illustrated by the following examples:

[0017] Example 1

[0018] 15 tons of dianthracene oil are charged into an intermittent distillation still. The dianthracene oil contains 3.9% of 1,2-benz[a]anthracene. The rectification column is filled with stainless steel wire mesh packing, and the number of theoretical plates is 80. Under vacuum distillation, the vacuum degree at the top of the column is -0.09 MPa, the reflux ratio is 20, and the fractions with the top temperature between 320 °C and 335 °C are collected, totaling 1,132 kg. Gas chromatography detection shows that it contains 46.23% of 1,2-benz[a]anthracene. 566 kg of medium wash oil is added to the crystallizer in advance, and stirring is started at a stirring speed of 18 r / min. The 1,2-benz[a]anthracene narrow fraction heated to 200 °C is added to the crystallizer. After heat preservation for 1 h, cooling water is passed to cool down, and the cooling rate is controlled at 10 °C / h. After cooling to 30 °C, it is kept warm for 1 h, and then centrifugally filtered to obtain 542 kg of crude 1,2-benz[a]anthracene with a content of 80.67%. These crude 1,2-benz[a]anthracenes are added to the sublimation kettle, the vacuum is started, and the vacuum degree in the sublimation kettle is maintained at -0.09 MPa. Steam heating is carried out, and the temperature of the material in the sublimation kettle is controlled at 160 °C. The sublimated substances floating out are collected. Gas chromatography detection shows that it contains 93.52% of 1,2-benz[a]anthracene, and the weight is 419 kg. These sublimated 1,2-benz[a]anthracenes are added to the crystallizer, and 419 kg of methanol is added. Stirring is started, the temperature is raised to the boiling point of methanol, and after heat preservation for 30 min, the temperature is uniformly reduced. After reducing to 20 °C, it is kept warm for 30 min, and then centrifugally filtered and sent to the oven for drying to obtain light yellow flaky crystals, which are refined 1,2-benz[a]anthracene, weighing 331 kg, with a purity of 98.04% and a total recovery rate of 55.47%.

[0019] The solvent medium wash oil does not need to be recovered and is directly used for benzene washing.

[0020] The solvent methanol is recovered and reused. The residue after methanol recovery can be added to the crude 1,2-benz[a]anthracene to improve the product recovery rate.

[0021] Example 2

[0022] 15 tons of dianthracene oil containing 3.9% of 1,2-benz[a]anthracene is charged into the batch distillation still. The rectification column is filled with stainless steel wire mesh packing and has 80 theoretical plates. Vacuum distillation is carried out with a top vacuum of -0.09 MPa and a reflux ratio of 25. The fractions with a top temperature between 320 °C and 335 °C are collected, totaling 1082 kg, and the gas chromatography detection shows that it contains 49.54% of 1,2-benz[a]anthracene. 541 kg of medium wash oil is added to the crystallizer in advance, the stirring is started at a stirring speed of 18 r / min, and the 1,2-benz[a]anthracene narrow fraction heated to 200 °C is added to the crystallizer. After holding the temperature for 1 h, cooling water is passed through to cool down, and the cooling rate is controlled at 8 °C / h. After cooling to 35 °C, it is held for 1 h, and then centrifugally filtered to obtain 544 kg of crude 1,2-benz[a]anthracene with a content of 82.39%. These crude 1,2-benz[a]anthracene are added to the sublimation kettle, the vacuum is started, and the vacuum in the sublimation kettle is maintained at -0.09 MPa. Steam heating is carried out, and the temperature of the material in the sublimation kettle is controlled at 160 °C. The sublimated substances floating out are collected, and the gas chromatography detection shows that it contains 94.05% of 1,2-benz[a]anthracene, weighing 428 kg. These sublimated 1,2-benz[a]anthracene are added to the crystallizer, and 428 kg of methanol is added. The stirring is started, the temperature is raised to the boiling point of methanol, and after holding for 30 min, the temperature is gradually decreased at a uniform speed. After cooling to 25 °C, it is held for 30 min, and then centrifugally filtered and sent to the oven for drying to obtain light yellow flaky crystals, which are refined 1,2-benz[a]anthracene, weighing 334 kg, with a purity of 98.35% and a total yield of 56.15%.

[0023] Example 3

[0024] 15 tons of dianthracene oil containing 3.9% of 1,2-benzanthracene is charged into the batch distillation kettle. The rectification column is filled with stainless steel wire mesh packing, with 80 theoretical plates. Under vacuum distillation, the vacuum degree at the top of the column is -0.09 MPa, and the reflux ratio is 30. The fractions with the top temperature between 320 °C and 335 °C are collected, totaling 1022 kg, and the gas chromatography detection shows that it contains 54.16% of 1,2-benzanthracene. 511 kg of medium wash oil is added to the crystallizer in advance, the stirring is started, and the stirring speed is 18 r / min. The 1,2-benzanthracene narrow fraction heated to 200 °C is added to the crystallizer. After heat preservation for 1 h, cooling water is passed to cool down, and the cooling rate is controlled at 5 °C / h. After cooling to 40 °C, it is kept warm for 1 h, and then centrifugally filtered to obtain 549 kg of crude 1,2-benzanthracene with a content of 84.58%. These crude 1,2-benzanthracene are added to the sublimation kettle, the vacuum is started, and the vacuum degree in the sublimation kettle is maintained at -0.09 MPa. Steam heating is carried out, and the temperature of the material in the sublimation kettle is controlled at 160 °C. The sublimated substances floating out are collected, and the gas chromatography detection shows that it contains 94.68% of 1,2-benzanthracene, and the weight is 441 kg. These sublimated 1,2-benzanthracene are added to the crystallizer, and 441 kg of methanol is added. The stirring is started, and the temperature is raised to the boiling point of methanol. After heat preservation for 30 min, the temperature is uniformly decreased. After cooling to 30 °C, it is kept warm for 30 min, and then centrifugally filtered and sent to the oven for drying to obtain light yellow flaky crystals, which are refined 1,2-benzanthracene. The weight is 340 kg, the purity is 98.59%, and the total yield is 57.30%.

Claims

1. A production method of 1,2-benzanthracene, characterized in that It includes the following steps: Step 1: Add dianthracene oil into a vacuum distillation device, and perform vacuum distillation to obtain a 1,2-benzanthracene narrow fraction with a 1,2-benzanthracene mass fraction of 45% - 55%; Step 2: Heat the 1,2-benzanthracene narrow fraction obtained in Step 1 to 200 °C, and then add it to a crystallizer with stirring together with medium wash oil at a mass ratio of narrow fraction: medium wash oil = 1:0.

5. Control the stirring speed at 15 r / min - 20 r / min, and then cool the material to 30 °C - 40 °C at a cooling rate of 5 °C - 10 °C / h. After centrifugal separation, obtain crude 1,2-benzanthracene with a content of 80% - 85%. The medium wash oil in the centrifugal filtrate does not need to be recovered and can be directly used for benzene washing; Step 3: Add the crude 1,2-benzanthracene obtained in Step 2 into a sublimation kettle. Control the vacuum degree in the sublimation kettle at -0.08 MPa - -0.09 MPa, and control the sublimation temperature at 150 °C - 160 °C to obtain sublimated 1,2-benzanthracene with a content of 93% - 95%; Step 4: Add the sublimated 1,2-benzanthracene obtained in Step 3 and methanol into the crystallizer at a mass ratio of 1:

1. Heat up to the boiling point of methanol, keep it at a constant temperature for 30 min, then cool it to 20 °C - 30 °C by passing cooling water. After centrifugal filtration and drying, obtain refined 1,2-benzanthracene with a content greater than 98%. The filtrate is subjected to vacuum distillation to recover the methanol solvent for recycling; 2. The production method of 1,2-benzanthracene according to claim 1, characterized in that The distillation column in the vacuum distillation device described in Step 1 is a packed column, and the intermittent distillation method is adopted. The vacuum degree at the top of the column is -0.08 MPa - -0.09 MPa, the reflux ratio is 20 - 30, and the number of theoretical plates is 80 - 100.

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