Polycyclic aromatic hydrocarbon separation method

Abstract

The present invention relates to the technical field of polycyclic aromatic hydrocarbon separation, and provides a polycyclic aromatic hydrocarbon separation method. In the present invention, firstly, a mixed solvent and a mixture to be separated are mixed and then filtered to obtain a filter cake and a filtrate, then a back-extractant and the filtrate are mixed and then separated, wherein the mixed solvent is a naphthyl mixed solvent or an imidazole mixed solvent, and the mixture to be separated is a mixture containing a bicyclic aromatic hydrocarbon and a tricyclic aromatic hydrocarbon or a mixture containing a tricyclic aromatic hydrocarbon and a tetracyclic aromatic hydrocarbon. According to the present invention, the mixture containing the bicyclic aromatic hydrocarbon and the tricyclic aromatic hydrocarbon is separated by using the naphthyl mixed solvent, the mixture containing the tricyclic aromatic hydrocarbon and the tetracyclic aromatic hydrocarbon is separated by using the imidazole mixed solvent, and the naphthyl mixed solvent or the imidazole mixed solvent can be recycled. Additionally, the separation method provided by the present invention has simple steps, low energy consumption and a simple technological process.

Description

A method for separating polycyclic aromatic hydrocarbons Technical Field

[0001] The present invention relates to the technical field of polycyclic aromatic hydrocarbon separation, and in particular to a method for separating polycyclic aromatic hydrocarbons. Background Art

[0002] Polycyclic aromatic hydrocarbons are essential raw materials in the chemical industry, possessing high application value and broad application across a wide range of research fields. Tricyclic and tetracyclic aromatic hydrocarbons exhibit excellent fluorescence and can be used as raw materials for the preparation of optoelectronic materials. Furthermore, after hydrogenation, tricyclic and tetracyclic aromatic hydrocarbons can be used as additives in high-energy-density fuels to enhance fuel performance. Coal tar is rich in polycyclic aromatic hydrocarbons, with dicyclic, tricyclic, and tetracyclic aromatic hydrocarbons being particularly abundant.

[0003] Currently, the main separation methods include distillation, supercritical extraction, zone melting, column chromatography, and extraction. Distillation is the most widely used method, but it has disadvantages such as high energy consumption and a long process flow. In contrast, extraction is simple to operate and requires less equipment. However, since it is difficult to find obvious recognition sites for dicyclic aromatic hydrocarbons, tricyclic aromatic hydrocarbons, and tetracyclic aromatic hydrocarbons, it is currently difficult to find suitable solvents to separate them. Therefore, it is of great significance to provide a method for separating polycyclic aromatic hydrocarbons to achieve the separation of dicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbon mixtures and the separation of tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbon mixtures.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide a method for separating polycyclic aromatic hydrocarbons to solve the problems of complicated separation steps and high energy consumption in the prior art for separating a mixture of bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a mixture of tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for separating polycyclic aromatic hydrocarbons, comprising the following steps:

[0008] (1) mixing the mixed solvent and the mixture to be separated and filtering to obtain a filter cake and a filtrate;

[0009] (2) mixing the stripping agent and the filtrate and separating them;

[0010] The mixed solvent is a naphthyl mixed solvent or an imidazole mixed solvent;

[0011] The mixture to be separated is a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons.

[0012] Preferably, in step (1), the mass ratio of the mixed solvent to the mixture to be separated is 1 to 8:1.

[0013] Preferably, a naphthyl mixed solvent is used to separate the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, wherein the naphthyl mixed solvent is a mixture of an alcohol compound and a naphthyl compound.

[0014] Preferably, the concentration of the naphthyl compound is 2 to 20 mol%.

[0015] Preferably, the naphthyl compound comprises one or more of naphthyl acetonitrile, naphthyl acetic acid, naphthyl acetamide, naphthyl methanol, naphthyl ethanol, naphthylamine and naphthol.

[0016] Preferably, the separation of the mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons uses an imidazole mixed solvent, wherein the imidazole mixed solvent is a mixture of an alcohol compound and an imidazole compound.

[0017] Preferably, the alcohol compound comprises one or more of ethylene glycol, propylene glycol, pentanediol, heptanediol and octanediol.

[0018] Preferably, the imidazole compound comprises one or more of methylimidazole, ethylimidazole, propylimidazole and butylimidazole.

[0019] Preferably, the concentration of the imidazole compound is 10 to 80 mol%.

[0020] Beneficial effects of the present invention:

[0021] (1) The present invention utilizes a naphthyl mixed solvent to separate a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, and utilizes an imidazole mixed solvent to separate a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons, and the naphthyl mixed solvent or the imidazole mixed solvent can be recycled.

[0022] (2) The separation method provided by the present invention has simple steps, low energy consumption, simple process flow, low solvent toxicity, and the naphthyl mixed solvent and imidazole mixed solvent used can be efficiently recycled and regenerated by the back extraction method. DETAILED DESCRIPTION

[0023] The present invention provides a method for separating polycyclic aromatic hydrocarbons, comprising the following steps:

[0024] (1) mixing the mixed solvent and the mixture to be separated and filtering to obtain a filter cake and a filtrate;

[0025] (2) mixing the stripping agent and the filtrate and separating them;

[0026] The mixed solvent is a naphthyl mixed solvent or an imidazole mixed solvent;

[0027] The mixture to be separated is a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons.

[0028] In the present invention, the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons is a model mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a fraction of coal tar at 220-320° C., preferably a model mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons.

[0029] In the present invention, the model mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons is a mixture of two or more of naphthalene, methylnaphthalene, anthracene, phenanthrene and fluorene, preferably a mixture of naphthalene and phenanthrene, a mixture of naphthalene and anthracene, or a mixture of naphthalene, phenanthrene and fluorene.

[0030] In the present invention, the mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons is a model mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons or a fraction of coal tar at 300-400° C., preferably a model mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons.

[0031] In the present invention, the model mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons is a mixture of two or more of anthracene, phenanthrene, fluorene, pyrene and fluoranthene, preferably a mixture of phenanthrene and pyrene or a mixture of phenanthrene, pyrene and fluoranthene or a mixture of phenanthrene, anthracene, pyrene and fluoranthene or a mixture of phenanthrene, anthracene, fluorene, pyrene and fluoranthene.

[0032] In the present invention, in step (1), the mass ratio of the mixed solvent to the mixture to be separated is 1 to 8:1, preferably 1:1, 2:1, 3:1, 5:1, 6:1, and preferably 3:1 or 5:1.

[0033] In the present invention, in step (1), the mixed solvent and the mixture to be separated are mixed and then stirred, wherein the stirring temperature is controlled at 20-90°C, preferably 30-80°C, preferably 30°C, 40°C, 50°C, or 70°C.

[0034] In the present invention, in step (2), the stripping agent and the filtrate are mixed and then stirred, wherein the stirring temperature is controlled at 20-40°C, preferably 25-35°C, and more preferably 30°C.

[0035] In the present invention, a naphthyl mixed solvent is used to separate the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, wherein the naphthyl mixed solvent is a mixture of an alcohol compound and a naphthyl compound.

[0036] In the present invention, the alcohol compound in the naphthalene mixed solvent comprises one or more of ethylene glycol, propylene glycol, pentanediol, heptanediol and octanediol, preferably one or more of ethylene glycol, propylene glycol and pentanediol, and more preferably ethylene glycol.

[0037] In the present invention, the concentration of the naphthyl compound is 2 to 20 mol %, preferably 5 to 18 mol %, and more preferably 10 to 15 mol %.

[0038] In the present invention, the naphthyl compound comprises one or more of naphthyl acetonitrile, naphthyl acetic acid, naphthyl acetamide, naphthyl methanol, naphthyl ethanol, naphthylamine and naphthol, preferably one or more of naphthyl acetonitrile, naphthyl acetic acid, naphthyl methanol and naphthol, more preferably naphthyl methanol.

[0039] In the present invention, the stripping agent used for separating the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons is one or more of n-hexane, n-heptane, n-octane, n-nonane and n-decane, preferably one or more of n-hexane, n-heptane, n-octane and n-nonane, further preferably n-hexane and / or n-heptane.

[0040] In the present invention, in the separation of the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, the mass ratio of the stripping agent to the filtrate is 2 to 20:1, preferably 5 to 15:1, and more preferably 8 to 12:1.

[0041] In the present invention, the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons is separated to obtain a mixture of a stripping agent and bicyclic aromatic hydrocarbons, which is then subjected to reduced pressure distillation to obtain the stripping agent and bicyclic aromatic hydrocarbons, wherein the reduced pressure distillation temperature is 30 to 70°C, preferably 40 to 60°C, more preferably 50°C, and the time is 30 to 90 minutes, preferably 40 to 80 minutes, more preferably 50 to 70 minutes.

[0042] In the present invention, an imidazole mixed solvent is used to separate the mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons, wherein the imidazole mixed solvent is a mixture of an alcohol compound and an imidazole compound.

[0043] In the present invention, the alcohol compound comprises one or more of ethylene glycol, propylene glycol, pentanediol, heptanediol and octanediol, preferably one or more of ethylene glycol, propylene glycol and pentanediol, more preferably ethylene glycol.

[0044] In the present invention, the imidazole compound comprises one or more of methyl imidazole, ethyl imidazole, propyl imidazole and butyl imidazole, preferably one or more of ethyl imidazole, propyl imidazole and butyl imidazole, and more preferably ethyl imidazole and / or butyl imidazole.

[0045] In the present invention, the concentration of the imidazole compound is 10 to 80 mol%, preferably 15 to 75 mol%, and more preferably 20 to 60 mol%.

[0046] In the present invention, for separating the mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons, the stripping agent is preferably ethylene glycol, wherein the ethylene glycol and the filtrate are mixed by slowly adding the ethylene glycol to the filtrate.

[0047] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 10 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 1:1, stirred at 30 ° C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0050] The n-hexane and the filtrate were mixed in a mass ratio of 10:1 and stirred at 30° C. for 50 minutes. Finally, the naphthyl mixed solvent and the mixture of n-hexane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0051] A mixture of n-hexane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 50° C. for 50 min to obtain n-hexane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 89.1% and the yield was 60%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 87.2% and the yield was 60%.

[0052] Example 2

[0053] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 10 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 2:1, stirred at 30 ° C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0054] n-heptane and the filtrate were mixed in a mass ratio of 15:1 and stirred at 30° C. for 50 minutes. Finally, the naphthyl mixed solvent and the mixture of n-heptane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0055] A mixture of n-heptane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 60° C. for 40 minutes to obtain n-heptane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 90.5% and the yield was 62%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 89.5% and the yield was 61%.

[0056] Example 3

[0057] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 10 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 3:1, stirred at 50 ° C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0058] The n-octane and the filtrate were mixed in a mass ratio of 5:1 and stirred at 50°C for 50 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0059] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 94.5% and the yield was 67%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 94.9% and the yield was 68%.

[0060] Example 4

[0061] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 15 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 5:1, stirred at 30 ° C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0062] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0063] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 92.5% and the yield was 65%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 93.1% and the yield was 66%.

[0064] Example 5

[0065] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled off to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is formed by mixing naphthaleneacetonitrile and ethylene glycol, and the concentration of naphthaleneacetonitrile is 8 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 2:1 and stirred at 30 ° C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0066] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0067] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 90.5% and the yield was 62%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 91.6% and the yield was 62%.

[0068] Example 6

[0069] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled off to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is formed by mixing naphthylacetic acid and ethylene glycol, and the concentration of naphthylacetonitrile is 12 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 3:1 and stirred at 30 ° C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0070] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0071] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 50° C. for 60 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 91.8% and the yield was 61%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 92.8% and the yield was 64%.

[0072] Example 7

[0073] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthylacetamide and ethylene glycol, and the concentration of naphthylacetamide is 18 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 6:1, and stirred at 70 ° C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0074] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0075] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 40° C. for 30 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 86.8% and the yield was 55%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 89.1% and the yield was 61%.

[0076] Example 8

[0077] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthaleneethanol and ethylene glycol, and the concentration of naphthaleneethanol is 18 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 8:1, stirred at 40 ° C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0078] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0079] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 70° C. for 30 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 89.6% and the yield was 60%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 90.5% and the yield was 63%.

[0080] Example 9

[0081] 2 g of naphthalene and 1 g of phenanthrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of naphthalene and phenanthrene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthol and ethylene glycol, and the concentration of naphthol is 18 mol%), a mixture of naphthalene and phenanthrene are mixed in a mass ratio of 3:1 and stirred at 50°C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0082] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0083] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 91.3% and the yield was 61%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 93.3% and the yield was 63%.

[0084] Example 10

[0085] 2 g of naphthalene and 1 g of anthracene are mixed in dichloromethane, stirred and heated at room temperature, and then the dichloromethane is distilled off to obtain a mixture of naphthalene and anthracene. A naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 5 mol%), a mixture of naphthalene and anthracene are mixed in a mass ratio of 3:1, stirred at 40°C, and finally filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0086] The n-octane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20°C for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-octane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0087] A mixture of n-octane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-octane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 96.5% and the yield was 67%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 96.8% and the yield was 66%.

[0088] Example 11

[0089] 2 g of naphthalene, 0.5 g of phenanthrene, 0.3 g of anthracene and 0.2 g of fluorene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of naphthalene, phenanthrene, anthracene and fluorene. A mixture of a naphthyl mixed solvent (wherein the naphthyl mixed solvent is a mixture of naphthalenemethanol and ethylene glycol, and the concentration of naphthalenemethanol is 10 mol%), naphthalene, phenanthrene, anthracene and fluorene was mixed in a mass ratio of 3:1 and stirred at 50 ° C. Finally, it was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0090] The n-hexane and the filtrate were mixed in a mass ratio of 20:1 and stirred at 20° C. for 90 minutes. Finally, the naphthalene mixed solvent and the mixture of n-hexane and bicyclic aromatic hydrocarbons were separated by washing and filtration.

[0091] A mixture of n-hexane and bicyclic aromatic hydrocarbons was distilled under reduced pressure at 30° C. for 90 minutes to obtain n-hexane and bicyclic aromatic hydrocarbons. The purity of the obtained bicyclic aromatic hydrocarbon compound was 95.4% and the yield was 66%. The purity of the obtained tricyclic aromatic hydrocarbon compound was 96.5% and the yield was 67%.

[0092] Example 12

[0093] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and ethylene glycol, and the concentration of ethylimidazole is 30 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 1:1 and stirred at 30 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0094] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 12 was 84.5%, and the yield was 58%. The purity of the tetracyclic aromatic hydrocarbon compound was 83.5%, and the yield was 52%.

[0095] Example 13

[0096] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and propylene glycol, and the concentration of ethylimidazole is 40 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 2:1 and stirred at 40 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0097] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 40°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 13 was 88.4%, with a yield of 60%. The purity of the tetracyclic aromatic hydrocarbon compound was 86.5%, with a yield of 58%.

[0098] Example 14

[0099] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and ethylene glycol, and the concentration of ethylimidazole is 40 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 3:1 and stirred at 40 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0100] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 20°C, until the solid mass became constant, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 14 was 86.4%, and the yield was 58%. The purity of the tetracyclic aromatic hydrocarbon compound was 83.5%, and the yield was 52%.

[0101] Example 15

[0102] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and ethylene glycol, and the concentration of ethylimidazole is 40 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 5:1 and stirred at 30 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0103] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass became constant, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 15 was 81.9% and the yield was 52%. The purity of the tetracyclic aromatic hydrocarbon compound was 80.4% and the yield was 52%.

[0104] Example 16

[0105] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of methylimidazole and pentanediol, and the concentration of methylimidazole is 50 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 2:1 and stirred at 40 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0106] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant value. Addition was then stopped, and the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 16 was 84.2%, and the yield was 56%. The purity of the tetracyclic aromatic hydrocarbon compound was 83.9%, and the yield was 55%.

[0107] Example 17

[0108] 2 g of phenanthrene and 1 g of pyrene were mixed in dichloromethane, stirred and heated at room temperature, and then the dichloromethane was distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of propyl imidazole and ethylene glycol, and the concentration of propyl imidazole is 20 mol%), a mixture of phenanthrene and pyrene were mixed in a mass ratio of 2:1 and stirred at 40 ° C. Finally, the mixture was filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0109] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 17 was 83.9% and the yield was 57%. The purity of the tetracyclic aromatic hydrocarbon compound was 84.9% and the yield was 59%.

[0110] Example 18

[0111] 2 g of phenanthrene and 1 g of pyrene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of phenanthrene and pyrene. An imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of butyl imidazole and octanediol, and the concentration of butyl imidazole is 60 mol%), a mixture of phenanthrene and pyrene are mixed in a mass ratio of 8:1 and stirred at 40 ° C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0112] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass became constant, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 18 was 83.2%, and the yield was 58%. The purity of the tetracyclic aromatic hydrocarbon compound was 82.7%, and the yield was 56%.

[0113] Example 19

[0114] 2 g of phenanthrene, 0.5 g of pyrene and 0.5 g of fluoranthene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of phenanthrene, pyrene and fluoranthene. A mixture of an imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and ethylene glycol, and the concentration of ethylimidazole is 40 mol%), a mixture of phenanthrene, pyrene and fluoranthene is mixed in a mass ratio of 2:1 and stirred at 50 ° C. Finally, it is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0115] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 19 was 88.1%, and the yield was 58%. The purity of the tetracyclic aromatic hydrocarbon compound was 88.6%, and the yield was 59%.

[0116] Example 20

[0117] 1 g of phenanthrene, 1 g of anthracene, 0.5 g of pyrene and 0.5 g of fluoranthene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of phenanthrene, anthracene, pyrene and fluoranthene. A mixture of an imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and ethylene glycol, and the concentration of ethylimidazole is 70 mol%), a mixture of phenanthrene, anthracene, pyrene and fluoranthene is mixed in a mass ratio of 3:1 and stirred at 40°C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0118] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 20 was 89.1%, with a yield of 60%. The purity of the tetracyclic aromatic hydrocarbon compound was 92.5%, with a yield of 61%.

[0119] Example 21

[0120] 1 g of phenanthrene, 1 g of anthracene, 0.2 g of fluorene, 0.5 g of pyrene and 0.5 g of fluoranthene are mixed in dichloromethane, stirred and heated at room temperature, and then dichloromethane is distilled to obtain a mixture of phenanthrene, anthracene, fluorene, pyrene and fluoranthene. A mixture of an imidazole mixed solvent (wherein the imidazole mixed solvent is a mixture of ethylimidazole and heptanediol, and the concentration of ethylimidazole is 80 mol%), phenanthrene, anthracene, fluorene, pyrene and fluoranthene are mixed in a mass ratio of 6:1 and stirred at 50 ° C. Finally, the mixture is filtered to obtain a filter cake (tricyclic aromatic hydrocarbons) and a filtrate.

[0121] Ethylene glycol was slowly added to the filtrate, maintaining the temperature at 30°C, until the solid mass reached a constant level, at which point the addition was stopped. Finally, the mixture was washed and filtered to obtain an imidazole mixed solvent and a tetracyclic aromatic hydrocarbon compound. The purity of the tricyclic aromatic hydrocarbon obtained in Example 21 was 87.1%, with a yield of 57%. The purity of the tetracyclic aromatic hydrocarbon compound was 90.5%, with a yield of 60%.

[0122] As can be seen from the above embodiments, the present invention provides a method for separating polycyclic aromatic hydrocarbons. The present invention first mixes a mixed solvent and a mixture to be separated and then filters to obtain a filter cake and a filtrate, and then mixes a stripping agent and the filtrate and separates them, wherein the mixed solvent is a naphthyl mixed solvent or an imidazole mixed solvent, and the mixture to be separated is a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons. The present invention utilizes a naphthyl mixed solvent to separate a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons, and utilizes an imidazole mixed solvent to separate a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons, and the naphthyl mixed solvent or the imidazole mixed solvent can be recycled. In addition, the separation method provided by the present invention has simple steps, low energy consumption, and a simple process flow.

[0123] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for separating polycyclic aromatic hydrocarbons, characterized in that: The steps include: (1) mixing a mixed solvent and a mixture to be separated and filtering the mixture to obtain a filter cake and a filtrate; (2) mixing the stripping agent and the filtrate and then separating them; The mixed solvent is a naphthyl mixed solvent or an imidazole mixed solvent; The mixture to be separated is a mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons or a mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons.

2. The separation method according to claim 1, characterized in that In the step (1), the mass ratio of the mixed solvent to the mixture to be separated is 1 to 8:

1.

3. The separation method according to claim 1 or 2, characterized in that The separation of the mixture containing bicyclic aromatic hydrocarbons and tricyclic aromatic hydrocarbons uses a naphthyl mixed solvent, wherein the naphthyl mixed solvent is a mixture of an alcohol compound and a naphthyl compound.

4. The separation method according to claim 3, characterized in that The concentration of the naphthyl compound is 2 to 20 mol%.

5. The separation method according to claim 3, characterized in that The naphthyl compound comprises one or more of naphthyl acetonitrile, naphthyl acetic acid, naphthyl acetamide, naphthyl methanol, naphthyl ethanol, naphthyl amine and naphthol.

6. The separation method according to claim 1 or 2, characterized in that: The separation of the mixture containing tricyclic aromatic hydrocarbons and tetracyclic aromatic hydrocarbons uses an imidazole mixed solvent, wherein the imidazole mixed solvent is a mixture of an alcohol compound and an imidazole compound.

7. The separation method according to claim 6, characterized in that The alcohol compound comprises one or more of ethylene glycol, propylene glycol, pentanediol, heptanediol and octanediol.

8. The separation method according to claim 6, characterized in that The imidazole compound comprises one or more of methyl imidazole, ethyl imidazole, propyl imidazole and butyl imidazole.

9. The separation method according to claim 7 or 8, characterized in that The concentration of the imidazole compound is 10-80 mol%.