Method for separating phenolic substances from phenol-containing coal tar

Abstract

The invention provides a method for separating phenol substances from phenol-containing coal tar, which comprises the following steps: rectifying the phenol-containing coal tar to obtain various phenol oil mixtures containing different phenol distributions, and separating various phenol products from various dephenolized phenol oils in different distillation ranges by adopting a proper separation means to obtain the phenol substances. And high-quality phenol products with different high purities are obtained. The method disclosed by the invention can be used for separating and utilizing phenol products and oil products to the greatest extent, and has good industrial application value and economic value.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and organic synthesis of coal coking products, and in particular, the invention relates to a method for separating phenolic substances from phenol-containing coal tar. Background Art

[0002] Crude phenol is a mixture of a series of phenolic substances, and is one of the main components of coal tar, a byproduct of coal-to-coke, blue carbon, and synthesis gas. Phenolic substances contain hydroxyl groups, which will cause an increase in the oxygen content in coal tar. Not only will they cause additional hydrogen consumption during coal tar hydrogenation, but the generated water will also have an adverse effect on the catalyst. In addition, high-purity phenolic substances are widely used in the fields of pesticides, medicine, dyes, etc. At present, the development of domestic coal chemical industry has brought a large amount of coal tar, which is rich in a large amount of phenol oil and phenolic compounds. If the phenolic substances therein can be separated, it can save resources, have high added value, and produce good economic benefits. At this stage, the main industrial dephenolization technology is the alkali washing dephenolization method. This method is simple to operate and has high efficiency, but the process needs to consume a large amount of strong acid and alkali, has high production cost, serious equipment corrosion, and produces a large amount of difficult-to-treat phenol-containing wastewater. These shortcomings seriously limit the industrial application of the alkali washing dephenolization method.

[0003] In addition to the alkaline elution dephenolization method, the methods for dephenolization of industrial phenol oil include extractive distillation and double solvent extraction. Extractive distillation is to continuously add high boiling point solvents, such as triacetin, cyclopentane, diethylene glycol, etc., to the upper part of the distillation tower to extract phenolic compounds into the solvent, and come out of the tower bottom with the solvent, while neutral oils and pyridine substances are insoluble in the solvent and evaporated from the top of the tower. For example, Chinese patent application CN201410162519.X discloses a method for extracting phenolic compounds in coal direct liquefaction oil by extractive distillation. Practice has proved that the effect of simple extractive distillation is not ideal, especially for some neutral oils and pyridine substances with high boiling points. It is difficult to obtain crude phenol products that meet national standards. The solvent extraction method is to add certain solvents with high solubility for phenols and low solubility for neutral oils to the phenol oil system, so as to separate phenolic substances from phenol oil. The general solvents include superheated water, salt aqueous solution and alcohol aqueous solution. This method has a good effect on the removal and extraction of neutral oil, but because phenols are weakly acidic and pyridines are weakly alkaline, pyridines will also be carried over during the solvent extraction of phenols, which brings about the difficulty of further separating pyridine. In addition, two solvents are required in double solvent extraction, which is complicated and takes a long time. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, an embodiment of the present invention provides a method for separating phenolic substances from phenol-containing coal tar.

[0005] The embodiment of the present invention provides a method for separating phenolic substances from phenol-containing coal tar, comprising the following steps:

[0006] S1: firstly carry out atmospheric distillation to remove water from phenol-containing coal tar, and then carry out vacuum distillation to obtain light oil fraction with a distillation range of <170°C, phenol oil fraction with a distillation range of 170-230°C, tricresol phenol oil fraction with a distillation range of 231-240°C, catechol phenol oil fraction with a distillation range of 241-260°C, and resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300°C; wherein the water and the light oil fraction with a distillation range of <170°C are mixed, heated and stirred, and allowed to stand for stratification to obtain dephenolization wastewater and a phenol-containing light oil fraction with a distillation range of <170°C;

[0007] S2: refining and separating the phenol oil fraction with a distillation range of 170-230° C. in step S1; wherein the phenol oil fraction with a distillation range of 170-230° C. includes a phenol / o-cresol phenol oil fraction with a distillation range of 170-195° C., a mixed cresol phenol oil fraction with a distillation range of 196-208° C., a mixed xylenol phenol oil fraction with a distillation range of 209-222° C., and a 3,4-xylenol / m-isopropylphenol phenol oil fraction with a distillation range of 223-230° C.;

[0008] S3: alkylating and separating the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1;

[0009] S4: performing etherification separation on the catechol phenol oil fraction with a distillation range of 241 to 260° C. described in step S1;

[0010] S5: performing etherification separation on the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. described in step S1.

[0011] In some embodiments, in step S1, the heating and stirring temperature is 50-80° C., and the stirring time is 0.5-1 h.

[0012] In some embodiments, the specific steps of step S2 include: refining and separating the phenol / o-cresol phenol oil fraction with a distillation range of 170-195°C, the mixed cresol phenol oil fraction with a distillation range of 196-208°C, the mixed xylenol phenol oil fraction with a distillation range of 209-222°C, and the 3,4-xylenol / m-isopropylphenol oil fraction with a distillation range of 223-230°C.

[0013] In some embodiments, the specific steps of step S3 include:

[0014] S31: subjecting the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1 to an alkylation reaction with an olefin under acid catalysis, and then adding liquid alkali to the reaction product, and then subjecting the reaction product to vacuum distillation to obtain phenol-containing phenol oil, 6-tert-butyl-3,4-dimethylphenol, 6-tert-butyl-3-methyl-4-ethylphenol, and 2,6-di-tert-butyl-p-isopropylphenol;

[0015] S32: Add liquid alkali to the phenol-containing phenol oil obtained in step S31, heat to 60-80°C and stir for 0.5-1h, keep warm and let stand for 1h, separate the layers, remove the water layer, and then add water to the phenol oil layer to wash to obtain dephenolized phenol oil; add sulfuric acid to the water layer to neutralize it to neutrality, and add a non-water-soluble solvent for extraction, separate the layers, recycle the obtained waste water, and distill the obtained solvent layer to obtain crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol; then purify the crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol respectively to obtain refined 3-methyl-5-ethylphenol and refined 2,3,5-trimethylphenol.

[0016] In some embodiments, in step S31, the acid includes at least one of sulfuric acid, phosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, a strong acid resin, and a solid acid, preferably sulfuric acid, p-toluenesulfonic acid, or a strong acid resin; the olefin is an olefin having carbon atoms of C3 to C12;

[0017] And / or, the water-insoluble solvent includes at least one of a benzene solvent, an ester solvent, an ether solvent, a halogenated alkane solvent, a halogenated aromatic hydrocarbon solvent, and a ketone solvent.

[0018] In some embodiments, in step S4, the etherification separation comprises any of the following methods:

[0019] 1) Direct etherification separation: adding a catalyst and an alkylating agent to the catechol phenol oil fraction with a distillation range of 241 to 260° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain a fine product of o-dimethyl ether and a crude product of 5-methoxyindane; then heating and mixing the crude product of 5-methoxyindane with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting methyl bromide; then cooling the remaining reaction liquid to separate the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, separating the layers, the water layer is a hydrobromic acid solution, and the material layer is distilled to recover trimethylbenzene, and a fine product of 5-indanol is obtained;

[0020] 2) Extraction with alkali solution and then etherification separation: add alkali solution to the catechol phenol oil fraction with a distillation range of 241-260° C. in step S1 to react, wash the reaction product with water, separate the layers to obtain a water layer and dephenolized phenol oil; then add an alkylating agent to the water layer to react, cool the reaction product and let it stand to separate the layers to obtain a water layer and a material layer; extract the water layer with toluene, separate the layers, and recycle the wastewater layer; mix the toluene layer with the material layer, first perform atmospheric distillation to recover toluene, and then perform vacuum distillation to collect dimethyl ether and 5-methoxyindane in sequence.

[0021] Further, in the method 1) of step S4, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, difatty sulfates, and difatty carbonates; the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo (5,4,0)-7-undecene;

[0022] And / or, in the method 2) of step S4, the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.

[0023] In some embodiments, in step S5, the etherification separation comprises any of the following methods:

[0024] 1) Direct etherification separation: adding a catalyst and an alkylating agent to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261 to 300° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain p-phenylenedimethyl ether and m-phenylenedimethyl ether;

[0025] 2) adding alkali solution for extraction and then performing etherification separation: adding alkali solution to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. in step S1 to react, washing the reaction product with water, and layering to obtain a water layer and dephenolized phenol oil; then adding an alkylating agent to the water layer for reaction, cooling the reaction product and standing to layer to obtain a water layer and a material layer; extracting the water layer with toluene, layering, recycling the obtained wastewater layer, mixing the obtained toluene layer with the material layer, firstly performing atmospheric distillation to recover toluene, and then performing vacuum distillation to collect the dimethylbenzene product and the crude isophenylene dimethyl ether; then heating and mixing the crude isophenylene dimethyl ether with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting bromoalkanes; cooling the remaining reaction solution and separating the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, layering, the water layer is a hydrobromic acid solution, and the trimethylbenzene is distilled to recover the trimethylbenzene, and 3-methoxyphenol and resorcinol are obtained.

[0026] Further, in the method 1) of step S5, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, difatty sulfates, and difatty carbonates; the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo(5,4,0)-7-undecene;

[0027] And / or, in the method 2) of step S5, the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.

[0028] The advantages and beneficial effects of the present invention are:

[0029] (1) According to the distribution of different phenolic substances in phenol-containing coal tar, the present invention adopts a more refined narrow distillation range distillation or fractional cutting method to obtain various phenol oil mixtures containing different phenol distributions, which is conducive to using appropriate separation means to separate various phenol products from various dephenolized phenol oils with different distillation ranges, and further, the phenol products and oil products can be separated and utilized to the greatest extent, which has good industrial application value and economic value.

[0030] (2) The present invention utilizes the characteristics that the boiling point of the methyl ether of phenolic substances is significantly lower than that of the corresponding phenols, and is also significantly lower than that of the oil substances in the distillation section, and at the same time utilizes the characteristics that the boiling point and melting point of the methyl ether of hydroquinone substances are significantly lower than that of the corresponding hydroquinone. The present invention uses the method of methyl etherification reaction to separate phenol, o-cresol, 2,6-xylenol, and a small amount of m-cresol from phenol oil in the mixed phenol fraction; utilizes the characteristics that the boiling point and melting point of the methyl ether of hydroquinone are significantly reduced, and separates hydroquinone from phenol oil through methyl etherification reaction. The methyl etherification reaction adopts the traditional alkaline catalysis method, and no new safety and environmental protection problems are added in the process. A large number of phenol resources are utilized, which can reduce the chemical synthesis of phenol, o-cresol, 2,6-xylenol, m-cresol, o-catechol, hydroquinone, hydroquinone, 5-indanol, methyl hydroquinone and other products, which can generally reduce carbon emissions and have good social benefits.

[0031] (3) The present invention utilizes phenol in raw materials such as cresol phenol oil, xylenol phenol oil and tricresol phenol oil to react with olefins to generate various tert-butylated phenols, increase the boiling point difference between tert-butylated phenol products and phenol oil, and then obtain dephenolated or partially dephenolated phenol oil, tert-butylated phenol products or intermediates through rectification, and the intermediates are then subjected to acidic catalytic decomposition and rectification to obtain various pure phenol products and tert-butylated derivatives thereof. The method obtains a wide variety of products and can adjust the types of products produced, the production process is flexible, stable and safe, the raw material sources are wide, the raw material price is cheap, and it has very good economic benefits.

[0032] (4) The present invention is particularly effective in separating cresol or m-cresol phenol oils with high 2,6-dimethylphenol and o-ethylphenol contents, and has high economic benefits. Therefore, the present invention is most effective in separating cresol mixtures obtained by refining crude phenol extracted from pyrolysis and gasification tars with high 2,6-dimethylphenol and o-ethylphenol contents. DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below. The embodiments are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0034] Where values ​​are described herein as a range, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or a specific sub-range is explicitly stated.

[0035] Herein, the words "comprises" and "includes" and variations thereof mean that other elements or integers which are permitted but not specifically described may be included.

[0036] In this article, the term "and / or" is merely a term used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0037] The embodiment of the present invention provides a method for separating phenolic substances from phenol-containing coal tar, comprising the following steps:

[0038] S1: firstly carry out atmospheric distillation to remove water from phenol-containing coal tar, and then carry out vacuum distillation to obtain light oil fraction with a distillation range of <170°C, phenol oil fraction with a distillation range of 170-230°C, tricresol phenol oil fraction with a distillation range of 231-240°C, catechol phenol oil fraction with a distillation range of 241-260°C, and resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300°C; wherein the water and the light oil fraction with a distillation range of <170°C are mixed, heated and stirred, and allowed to stand for stratification to obtain dephenolization wastewater and a phenol-containing light oil fraction with a distillation range of <170°C;

[0039] S2: refining and separating the phenol oil fraction with a distillation range of 170-230° C. in step S1; wherein the phenol oil fraction with a distillation range of 170-230° C. includes a phenol / o-cresol phenol oil fraction with a distillation range of 170-195° C., a mixed cresol phenol oil fraction with a distillation range of 196-208° C., a mixed xylenol phenol oil fraction with a distillation range of 209-222° C., and a 3,4-xylenol / m-isopropylphenol phenol oil fraction with a distillation range of 223-230° C.;

[0040] S3: alkylating and separating the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1;

[0041] S4: performing etherification separation on the catechol phenol oil fraction with a distillation range of 241 to 260° C. described in step S1;

[0042] S5: performing etherification separation on the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. described in step S1.

[0043] In some embodiments, in step S1, the heating and stirring temperature is 50-80° C., and the stirring time is 0.5-1 h.

[0044] In some embodiments, the specific steps of step S2 include: refining and separating the phenol / o-cresol phenol oil fraction with a distillation range of 170-195°C, the mixed cresol phenol oil fraction with a distillation range of 196-208°C, the mixed xylenol phenol oil fraction with a distillation range of 209-222°C, and the 3,4-xylenol / m-isopropylphenol oil fraction with a distillation range of 223-230°C.

[0045] In some embodiments, the specific steps of step S3 include:

[0046] S31: subjecting the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1 to an alkylation reaction with an olefin under acid catalysis, and then adding liquid alkali to the reaction product, and then subjecting the reaction product to vacuum distillation to obtain phenol-containing phenol oil, 6-tert-butyl-3,4-dimethylphenol, 6-tert-butyl-3-methyl-4-ethylphenol, and 2,6-di-tert-butyl-p-isopropylphenol;

[0047] S32: Add liquid alkali to the phenol-containing phenol oil obtained in step S31, heat to 60-80°C and stir for 0.5-1h, keep warm and let stand for 1h, separate the layers, remove the water layer, and then add water to the phenol oil layer to wash to obtain dephenolized phenol oil; add sulfuric acid to the water layer to neutralize it to neutrality, and add a non-water-soluble solvent for extraction, separate the layers, recycle the obtained waste water, and distill the obtained solvent layer to obtain crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol; then purify the crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol respectively to obtain refined 3-methyl-5-ethylphenol and refined 2,3,5-trimethylphenol.

[0048] In some embodiments, in step S31, the acid includes at least one of sulfuric acid, phosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, a strong acid resin, and a solid acid, preferably sulfuric acid, p-toluenesulfonic acid, or a strong acid resin; the olefin is an olefin with a carbon number of C3 to C12 (for example, propylene, butenes, pentenes, hexenes, heptenes, octenes, nonenes, decenes, undecenes, dodecenes, etc., preferably isobutylene);

[0049] And / or, the water-insoluble solvent includes at least one of a benzene solvent, an ester solvent, an ether solvent, a halogenated alkane solvent, a halogenated aromatic hydrocarbon solvent, and a ketone solvent.

[0050] In some embodiments, in step S4, the etherification separation comprises any of the following methods:

[0051] 1) Direct etherification separation: adding a catalyst and an alkylating agent to the catechol phenol oil fraction with a distillation range of 241 to 260° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain a fine product of o-dimethyl ether and a crude product of 5-methoxyindane; then heating and mixing the crude product of 5-methoxyindane with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting methyl bromide; then cooling the remaining reaction liquid to separate the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, separating the layers, the water layer is a hydrobromic acid solution, and the material layer is distilled to recover trimethylbenzene, and a fine product of 5-indanol is obtained;

[0052] 2) Extraction with alkali solution and then etherification separation: add alkali solution to the catechol phenol oil fraction with a distillation range of 241-260° C. in step S1 to react, wash the reaction product with water, separate the layers to obtain a water layer and dephenolized phenol oil; then add an alkylating agent to the water layer to react, cool the reaction product and let it stand to separate the layers to obtain a water layer and a material layer; extract the water layer with toluene, separate the layers, and recycle the wastewater layer; mix the toluene layer with the material layer, first perform atmospheric distillation to recover toluene, and then perform vacuum distillation to collect dimethyl ether and 5-methoxyindane in sequence.

[0053] Further, in the method 1) of step S4, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, dialiphatic sulfates (such as dimethyl sulfate), and dialiphatic carbonates (such as dimethyl carbonate); the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo (5,4,0)-7-undecene;

[0054] And / or, in the method 2) of step S4, the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.

[0055] In some embodiments, in step S5, the etherification separation comprises any of the following methods:

[0056] 1) Direct etherification separation: adding a catalyst and an alkylating agent to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261 to 300° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain p-phenylenedimethyl ether and m-phenylenedimethyl ether;

[0057] 2) adding alkali solution for extraction and then performing etherification separation: adding alkali solution to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. in step S1 to react, washing the reaction product with water, and layering to obtain a water layer and dephenolized phenol oil; then adding an alkylating agent to the water layer for reaction, cooling the reaction product and standing to layer to obtain a water layer and a material layer; extracting the water layer with toluene, layering, recycling the obtained wastewater layer, mixing the obtained toluene layer with the material layer, firstly performing atmospheric distillation to recover toluene, and then performing vacuum distillation to collect the dimethylbenzene product and the crude isophenylene dimethyl ether; then heating and mixing the crude isophenylene dimethyl ether with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting bromoalkanes; cooling the remaining reaction solution and separating the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, layering, the water layer is a hydrobromic acid solution, and the trimethylbenzene is distilled to recover the trimethylbenzene, and 3-methoxyphenol and resorcinol are obtained.

[0058] Further, in the method 1) of step S5, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, dialiphatic sulfates (such as dimethyl sulfate), and dialiphatic carbonates (such as dimethyl carbonate); the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo (5,4,0)-7-undecene;

[0059] And / or, in the method 2) of step S5, the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.

[0060] In the embodiment of the present invention, the alkyl group in the phenyl alkyl ether is removed by using a hydrobromic acid aqueous solution in a trimethylbenzene solution to obtain pure products such as various hydroquinones and hydroquinone monoalkyl ethers; and brominated alkanes are produced as by-products. The brominated alkanes can be reused as etherification agents for various hydroquinones.

[0061] It should be noted that the dephenolized phenol oil obtained in the above steps can be further separated and recovered into high-value materials according to composition analysis, and can also be hydrogenated to produce gasoline and diesel, etc.

[0062] It should be noted that the various high-quality products obtained in the embodiments of the present invention all refer to products whose purity can reach 99% or above.

[0063] The technical scheme of the present invention is further described in detail below in conjunction with specific examples. Unless otherwise specified, the various raw materials used in the examples are conventional commercial products, or can be prepared by known methods; and the experimental methods without specific conditions in the examples are conventional methods and conventional conditions well known in the art.

[0064] Example 1

[0065] A method for separating phenolic substances from phenol-containing coal tar comprises the following steps:

[0066] S1, adding 800,000 parts of phenol-containing coal tar from coal pyrolysis of an energy enterprise in Xinjiang into a distillation tower kettle, firstly performing atmospheric distillation (200 mmHg) to remove 1,381 parts of water, and then performing vacuum distillation (200-5 mmHg) to obtain 10,805 parts of a light oil fraction with a distillation range of <170°C, 110,301 parts of a phenol oil fraction with a distillation range of 170-230°C, 16,445 parts of a tricresol phenol oil fraction with a distillation range of 231-240°C, 37,724 parts of a catechol phenol oil fraction with a distillation range of 241-260°C, and 97,486 parts of a resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300°C;

[0067] Then, the above-mentioned 1381 parts of water and 10805 parts of light oil fraction with a distillation range of <170°C are added to the reactor, the temperature is raised to 60°C and stirred for 1 hour, the phenol in the water is dissolved in the light oil, and the mixture is allowed to stand and separate into layers, to obtain 1299 parts of preliminary dephenolized wastewater and 10884 parts of phenol-containing light oil fraction with a distillation range of <170°C, wherein the wastewater is sent to the wastewater treatment section.

[0068] S2, separation of phenol oil fraction with distillation range of 170-230℃:

[0069] The phenol oil fraction with a distillation range of 170 to 230° C. includes a phenol / o-cresol phenol oil fraction with a distillation range of 170 to 195° C., a mixed cresol phenol oil fraction with a distillation range of 196 to 208° C., a mixed xylenol phenol oil fraction with a distillation range of 209 to 222° C., and a 3,4-xylenol / m-isopropylphenol phenol oil fraction with a distillation range of 223 to 230° C.;

[0070] 1) Separation of phenol / o-cresol oil fractions with a distillation range of 170-195°C:

[0071] 110301 parts of phenol oil fraction with a distillation range of 170-230°C include 26964.4 parts of phenol / o-cresol phenol oil fraction with a distillation range of 170-195°C. Sampling and analysis showed that the phenol content was 50.8%, of which phenol contained 41.75% phenol, 45.61% o-cresol, 8.53% 2,6-dimethylphenol, 3.86% m-cresol (2.12% m-cresol, 1.74% p-cresol), and 0.25% others.

[0072] 13482 parts of the phenol / o-cresol phenol oil fraction with a boiling range of 170-195° C. in step S1 (comprising 2859.4 parts of phenol, 3123.8 parts of o-cresol, 584.2 parts of 2,6-dimethylphenol, 264.4 parts of m-cresol <145.2 parts of m-cresol, 119.2 parts of p-cresol>, 17.1 parts of other phenols, and 31 parts of aniline) were added to a reaction kettle, stirring was started, 98 parts of 50% sulfuric acid were added dropwise within 10 minutes, stirred for 30 minutes, allowed to stand for 30 minutes, and separated into layers. The obtained 150.8 parts of the acid water layer (containing the hydrogen sulfate of aniline, pyridine and its homologue sulfate) were collected in batches and then used to recover aniline and pyridine and their homologues; the obtained oil layer was washed with 50 parts of water for 30 minutes, allowed to stand for 1 hour, and the water layer was separated into 50.1 parts of the acid water layer. 12,000 parts of 30% sodium hydroxide aqueous solution were added dropwise to the phenolic oil layer after the alkaline substances were removed, stirring was started, the temperature was raised to 60°C and stirred for 1 hour, and the mixture was allowed to stand for 1 hour to separate, thereby obtaining 18,845.9 parts of aqueous solution, and 6,578.4 parts of dephenolized phenolic oil were separated; 5,600 parts of dimethyl sulfate were added dropwise to the separated aqueous solution, the dropping temperature was controlled not to exceed 60°C, the dropping time was about 3 hours, and the reaction was kept warm for 8 hours under a slightly boiling condition after the dropping was completed, and sampling and analysis showed that the reaction product contained 0.09% o-cresol, and then the reaction product was cooled to 80°C and allowed to stand for separation, the lower water layer was separated, the water layer was sent to a wastewater station, 100 parts of water were added to the material layer, and 15 parts of sulfuric acid were added dropwise under stirring, and the impurities were removed by washing for 1 hour. The material layer was separated into layers, and the material layer was washed once with 100 parts of water. The water was separated, and the obtained material layer was added to a rectification kettle (theoretical plate 250, and the tower kettle was added with 100 parts of high boiling point solvent) for vacuum distillation (pressure was -0.085MPa, reflux ratio was 20-25:1), and the total reflux was 2 hours for every 6 hours of distillation. 42.6 parts of the first portion (containing 18.7 parts of anisole), 3221.8 parts of 99.85% anisole (containing 3217.0 parts of anisole, 4.5 parts of o-methyl anisole, and 0.3 parts of others), 36.5 parts of the first intermediate distillate (containing 12.3 parts of anisole, 24.1 parts of o-methyl anisole, and 0.4 parts of others), 3409. 1 part (containing 2.5 parts of anisole, 3403.2 parts of o-methyl anisole, 2.2 parts of m-p-methyl anisole, and 1.2 parts of others), 91.7 parts of the second middle distillate (containing 58.3 parts of o-methyl anisole, 33.2 parts of m-p-methyl anisole, and 0.2 parts of others), 321.9 parts of 80.8% m-p-methyl anisole (containing 0.1 parts of o-methyl anisole, 260.1 parts of m-p-methyl anisole, 61.5 parts of 2,6-dimethyl anisole, and 0.2 parts of others), 562 parts of 99.68% 2,6-dimethyl anisole (containing 0.7 parts of m-p-methyl anisole, 560.2 parts of 2,6-dimethyl anisole, and 1.1 parts of others), 34.9 parts of the post-distillation fraction (including 22.3 parts, unreacted phenol 4.3 parts, other 8.3 parts);.

[0073] Among them, the first intermediate distillate and the second intermediate distillate are incorporated into the distillation product of the next batch of etherified products; 99.85% anisole, 99.83% o-methyl anisole, and 99.68% 2,6-dimethyl anisole are directly sold as products; 80.8% m-p-methyl anisole is used to separate and obtain raw materials for 99% m-methyl anisole, 99% p-methyl anisole, and 99% 2,6-dimethyl anisole. m-methyl anisole and p-methyl anisole are very important chemical raw materials, which are widely used in the fields of medicine, fragrances, and organic synthesis intermediates.

[0074] 2) Alkylation separation of mixed cresol phenol oil fraction with a distillation range of 196-208°C:

[0075] 20,000 parts of the phenol oil fraction with a distillation range of 170-230° C. obtained by distillation in step S1 are added into a distillation kettle, and 5,230 parts of mixed cresol phenol oil with a distillation range of 196-208° C. are obtained by distillation, wherein the content of phenol products in the phenol oil is 48.7%, and the phenol composition is: o-cresol 22.91%, 2,6-xylenol 15.67%, m-cresol 23%, p-cresol 15.33%, o-ethylphenol 6.08%, 2,4-xylenol 9.75%, and 2,5-xylenol 6.92%;

[0076] Add 5230 parts of the above-mentioned mixed cresol phenol oil with a distillation range of 196-208°C (containing 583.5 parts of o-cresol, 399.1 parts of 2,6-xylenol, 585.8 parts of m-cresol, 390.4 parts of p-cresol, 154.8 parts of o-ethylphenol, 248.3 parts of 2,4-xylenol, and 176.2 parts of 2,5-xylenol) into the reactor, and add 75 parts of sulfuric acid. Heat to 90°C under stirring, and then pass 2080 parts of isobutylene to react. The time for passing isobutylene is 6 hours. After the isobutylene is passed, keep the temperature for 2 hours, and then add 202 parts of 31% liquid alkali to neutralize to pH=8, separate the water layer, and add the material layer into a high-efficiency distillation tower (with a reflux ratio of 18-23:1). Distill to obtain 109.5 parts of diisobutylene, 705. 2 parts of 99.3% 6-tert-butyl-2-methylphenol, 472.5 parts of 99.1% 2-tert-butyl-4-methylphenol, 1854.2 parts of mixed tert-butylphenol (including 754.2 parts of 6-tert-butyl-3-methylphenol, 582.2 parts of 4-tert-butyl-2,6-xymethylphenol, 360.6 parts of 6-tert-butyl-2,4-xymethylphenol, and 154.8 parts of 6-tert-butyl-2-ethylphenol), 895.3 parts of still residue (including 256 parts of 4-tert-butyl-2,5-xymethylphenol, 237.6 parts of 4,6-di-tert-butyl-2-methylphenol, 160 parts of 2,6-di-tert-butyl-4-methylphenol, 181.3 parts of 4,6-di-tert-butyl-3-methylphenol, and 52.7 parts of 4,6-di-tert-butyl-2-ethylphenol);

[0077] To the above 1854.2 parts of mixed tert-butylphenol (including 754.2 parts of 6-tert-butyl-3-methylphenol, 582.2 parts of 4-tert-butyl-2,6-dimethylphenol, 360.6 parts of 6-tert-butyl-2,4-dimethylphenol, and 154.8 parts of 6-tert-butyl-2-ethylphenol), 148 parts of strongly acidic resin were added, stirring was started, and 471 parts of isobutylene were introduced after the temperature was raised to 110°C. The isobutylene was introduced for 4 hours, and then the reaction was kept at 110°C for 1 hour. Samples were taken and separated. The reaction product was analyzed, and when the content of 6-tert-butyl-3-methylphenol in the reaction product was 0.13%, it was qualified. The reaction product was filtered, and the filter cake was used as a filter cake. The filtrate was subjected to vacuum distillation to obtain 54 parts of the first fraction, 918.7 parts of other fractions (including 568.2 parts of 4-tert-butyl-2,6-dimethylphenol and 350.5 parts of 4-tert-butyl-2,4-dimethylphenol) and 1219 parts of the still residue (including 203.5 parts of 4,6-di-tert-butyl-2-ethylphenol and 1011.7 parts of 4,6-di-tert-butyl-3-methylphenol);

[0078] The 1219 parts of the still residue and the aforementioned 895.3 parts of the still residue (including 256 parts of 4-tert-butyl-2,5-dimethylphenol, 237.6 parts of 4,6-di-tert-butyl-2-methylphenol, 160 parts of 2,6-di-tert-butyl-4-methylphenol, 181.3 parts of 4,6-di-tert-butyl-3-methylphenol, and 52.7 parts of 4,6-di-tert-butyl-2-ethylphenol) were added to a high-efficiency distillation tower and distilled at a pressure of -0.095 MPa to obtain 624 parts of a mixture of 2,6-di-tert-butyl-4-methylphenol, 4-tert-butyl-2,5-dimethylphenol and 4,6-di-tert-butyl-2-methylphenol (including 227.2 parts of 4,6-di-tert-butyl-2,5-dimethylphenol, 245.8 parts of 4,6-di-tert-butyl-2-methylphenol, and 160 parts of 2,6-di-tert-butyl-4-methylphenol. ,6-di-tert-butyl-4-methylphenol 151 parts), 41.5 parts of the first intermediate distillate (including 10.7 parts of 4,6-di-tert-butyl-2-methylphenol, 8.9 parts of 2,6-di-tert-butyl-4-methylphenol, 8.9 parts of 4-tert-butyl-2,5-xymethylphenol, 12.9 parts of 4,6-di-tert-butyl-2-ethylphenol), 225.9 parts of 99.2% 4,6-di-tert-butyl-2-ethylphenol, 103.4 parts of the second intermediate distillate (including 86.1 parts of 4,6-di-tert-butyl-3-methylphenol and 17.3 parts of 4,6-di-tert-butyl-2-ethylphenol), and 1096.2 parts of still residue (4,6-di-tert-butyl-3-methylphenol); the first intermediate distillate and the second intermediate distillate are applied to the distillation of the next batch of still residue;

[0079] 12.7 parts of concentrated sulfuric acid were added to the mixture of 624 parts of 2,6-di-tert-butyl-4-methylphenol, 4-tert-butyl-2,5-xylenol and 4,6-di-tert-butyl-2-methylphenol, and the mixture was heated to 200° C. for reaction for 3 hours under stirring. The gas phase detected that the 4-tert-butyl-2,5-xylenol was 0.08%. After the reaction product was cooled, 9.1 parts of 31% liquid alkali was added to neutralize it to pH=7.5. The water layer was separated, and the obtained material layer was added to a distillation tower for distillation to obtain 109.5 parts of 99.7% o-cresol, 70.3 parts of 99.8% p-cresol, and 165.8 parts of 99.5% 2,5-xylenol. The recovered 259.8 parts of isobutylene were reused;

[0080] The above 225.9 parts of 99.2% 4,6-di-tert-butyl-2-ethylphenol were added to a reactor, and 5 parts of concentrated sulfuric acid were added. The temperature was raised to 195°C for reaction for 3 hours under stirring. The content of 6-tert-butyl-2-ethylphenol was 0.22% by gas phase detection. The reaction product was cooled and 13.6 parts of 31% liquid alkali were added to neutralize it to pH=7.5. The water layer was separated, and the residual material layer was added to a distillation tower for distillation to obtain 116.6 parts of 99.5% o-ethylphenol. 104.9 parts of isobutylene were recycled, and the kettle residue was 10 96.2 parts; 1096.2 parts of the kettle residue and 18 parts of concentrated sulfuric acid were added to the reactor, the temperature was raised to 150°C and maintained for 2 hours, and the reaction was stopped when the content of 6-tert-butyl-m-cresol was 40.3% by gas spectrum detection. The reaction product was slightly cooled and neutralized with 46.5 parts of 31% liquid alkali to a neutral pH, and the water layer was separated by standing. The obtained material layer was subjected to vacuum distillation to obtain 317.6 parts of 99.7% high-purity m-cresol and 312.3 parts of 99.3% 6-tert-butyl-3-cresol, and the recovered 445.7 parts of isobutylene were reused;

[0081] The aforementioned 918.7 parts of other fractions (including 568.2 parts of 4-tert-butyl-2,6-dimethylphenol and 350.5 parts of 4-tert-butyl-2,4-dimethylphenol) were added into the reactor, and 12.7 parts of concentrated sulfuric acid were added, and the temperature was raised to 200°C for reaction for 3 hours under stirring. The gas phase detected that the 4-tert-butyl-2,6-dimethylphenol was 0.10%. After the reaction product was cooled, 34.5 parts of 31% liquid alkali were added to neutralize it to pH = 8.0, and the water layer was separated. The obtained material layer was added into a 2,6-dimethylphenol distillation tower for distillation to obtain 389.9 parts of 99.8% 2,6-dimethylphenol and 237.1 parts of 99.3% 2,4-dimethylphenol. The recovered 243.2 parts of isobutylene were reused.

[0082] 3) Alkylation separation of mixed xylenol phenol oil fraction with a distillation range of 209-222°C:

[0083] 20,000 parts of the phenol oil fraction with a distillation range of 170-230° C. obtained by rectification in step S1 are added into a distillation kettle, and 5,042 parts of a mixed xylenol phenol oil fraction with a distillation range of 209-222° C. are obtained by rectification, wherein the content of phenol products in the phenol oil is 47.6%, and the phenol composition is: 25% of 2,4 / 2,5-xylenol, 23% of 3,5-xylenol, 32% of m-p-ethylphenol, 8.1% of 2,3-xylenol, and 8% of 3,4-xylenol;

[0084] Add 5042 parts of the above-mentioned mixed dimethylphenol oil fraction with a distillation range of 209-222°C and 150 parts of concentrated sulfuric acid into the reactor, start stirring, raise the oil bath temperature to 80°C, and introduce 1300 parts of isobutylene for 8 hours. After the introduction, keep warm for 2 hours, take samples for analysis, and the results show that the content of 6-tert-butyl-2,3-dimethylphenol is 0.26%, which is qualified. Then add 400 parts of liquid alkali and 200 parts of water to the reaction product to neutralize it to pH=7-8, separate the layers, and wash the material layer with 200 parts of water once. Separate the water to obtain the material layer, first perform atmospheric distillation to recover 73.2 parts of diisobutylene, and then perform vacuum distillation to obtain 3212.5 parts of phenol oil (containing 3, 5-xylenol, etc.), and continued distillation to obtain 492.3 parts of antioxidant 6-tert-butyl-2,4-xylenol with a content of 99.3%, 556.5 parts of a mixture of 4-tert-butyl-2,5-xylenol and 6-tert-butyl-3,4-xylenol, 505.7 parts of 98.3% 2,6-di-tert-butyl-p-ethylphenol, 356.5 parts of a mixture of 4,6-di-tert-butyl-2,3-xylenol and 4,6-di-tert-butyl-m-ethylphenol (of which the former accounts for 82.03%), and the still residue is a mixture of 4,6-di-tert-butyl-2,3-xylenol and 4,6-di-tert-butyl-m-ethylphenol, totaling 923 parts (of which the latter accounts for 92.40%);

[0085] 8.3 parts of concentrated sulfuric acid were added to the mixture of 556.5 parts of 4-tert-butyl-2,5-dimethylphenol and 6-tert-butyl-3,4-dimethylphenol, and the temperature was raised to 200° C. and maintained for 2 hours, then cooled to below 100° C., and then neutralized with liquid alkali to a neutral pH, and then subjected to vacuum distillation to obtain 205.9 parts of 99.5% 2,5-dimethylphenol and 169.1 parts of 99.3% 3,4-dimethylphenol;

[0086] 5.3 parts of concentrated sulfuric acid were added to the mixture of 356.5 parts of 4,6-di-tert-butyl-2,3-xylenol and 4,6-di-tert-butyl-m-ethylphenol, and the mixture was heated to 200° C. and maintained for 2 hours, then cooled to below 100° C., and then neutralized with liquid alkali to a neutral pH, and then subjected to vacuum distillation to obtain 165.8 parts of 85.3% 2,3-xylenol and 415.9 parts of 93.2% m-ethylphenol;

[0087] Then, 200 parts of methanol were added to 165.8 parts of 85.3% 2,3-xylenol and heated to dissolve, and then 2 parts of activated carbon were added for decolorization. After filtration, the filtrate was concentrated to recover 101 parts of methanol, and the residual material was cooled to 5°C for crystallization, and 121.6 parts of 95.8% 2,3-xylenol were obtained by filtration; then, 70 parts of methanol were added to 121.6 parts of 95.8% 2,3-xylenol and heated to dissolve, and then cooled to 0°C for crystallization, and 104.1 parts of 99.1% 2,3-xylenol were obtained by filtration;

[0088] Add 200 parts of methanol to 415.9 parts of 93.2% m-ethylphenol and heat to dissolve, then slowly cool to -10°C and keep warm for 1 hour, filter, rinse with 20 parts of cold methanol, and dry to obtain 339.8 parts of 99.2% m-ethylphenol;

[0089] 591 parts of 31% liquid alkali and 325 parts of water were added to the aforementioned 3212.5 parts of phenol oil (containing 3,5-xylenol, etc.) with stirring to extract 3,5-xylenol. The extraction temperature was 80°C, and the mixture was stirred for 1 hour. The mixture was allowed to stand for 1 hour, and the layers were separated. The lower layer was the water layer (containing 3,5-xylenol, etc.). The upper layer of phenol oil was washed once with 100 parts of water, and the layers were allowed to stand for separation to obtain 2639 parts of dephenolized phenol oil. The mother liquor was combined with the washing liquid, and 229.5 parts of 98% sulfuric acid were added dropwise with stirring to neutralize the mixture to pH=6-7. Then, 1000 parts and 300 parts of methyl isobutyl ketone were added in sequence to extract the mixture twice. The separated water layer was used for wastewater treatment, and the obtained material layer was added to a rectifying kettle for rectification treatment. 1292 parts of methyl isobutyl ketone were recovered for reuse, and 534.2 parts of 99.3% 3,5-xylenol were obtained at the same time. The total extraction rate of 3,5-xylenol was 96.1%.

[0090] 4) Alkylation separation of 3,4-dimethylphenol / m-isopropylphenol phenol oil distillate at a distillation range of 223-230°C:

[0091] 20,000 parts of the phenol oil fraction with a distillation range of 170-230° C. obtained by rectification in step S1 are added into a distillation kettle, and 5,365 parts of 3,4-xylenol / m-isopropylphenol phenol oil fraction with a distillation range of 223-230° C. are obtained by rectification, wherein the content of phenol products in the phenol oil is 44.8%, and the phenol composition is: m-isopropylphenol 0.6%, 3,5-xylenol 3.2%, 3,4-xylenol 41.5%, m-isopropylphenol 23.6%, p-isopropylphenol 19.3%, 2-ethyl-3-methylphenol 5.6%, 3-ethyl-5-methylphenol 3.5%, and others 2.7%;

[0092] Add the above 5365 parts of 3,4-xylenol / m-isopropylphenol phenol oil fraction and 150 parts of concentrated sulfuric acid into the reactor, start stirring, heat the oil bath to 75°C, and introduce 1500 parts of isobutylene for 10 hours. After the introduction, keep warm for 2 hours. Take samples for analysis. The content of 2-tert-butyl-p-isopropylphenol is 0.09%, which is qualified. Then add 400 parts of liquid alkali and 200 parts of water to the reaction product to neutralize it to pH=7-8, separate the layers, and wash the layers with 200 parts of water once. After the water is separated, the obtained layers are firstly recovered at normal pressure 83.2 parts of diisobutylene, and then vacuum distilled to obtain 3126.3 parts of phenol oil (containing 76.5 parts of 3,5-xylenol, 83.6 parts of 3-ethyl-5-methylphenol, 19.3 parts of other phenols, etc.) , and continued distillation to obtain 1341.9 parts of 6-tert-butyl-3,4-dimethylphenol with a content of 99.64% (including 1337.1 parts of 6-tert-butyl-3,4-dimethylphenol and 4.8 parts of 6-tert-butyl-m-isopropyl phenol), 168.5 parts of a mixture of 6-tert-butyl-3,4-dimethylphenol and 6-tert-butyl-m-isopropyl phenol (including 101.2 parts of 6-tert-butyl-3,4-dimethylphenol and 67.3 parts of 6-tert-butyl-m-isopropyl phenol), 716.1 parts of 99.68% 6-tert-butyl-m-isopropyl phenol (including 713.8 parts of 6-tert-butyl-m-isopropyl phenol and 2.3 parts of 6-tert-butyl-3,4-dimethylphenol), 66.9 parts of the first transition fraction (including 6.8 parts of 6-tert-butyl-m-isopropyl phenol , 27.3 parts of 2,6-di-tert-butyl-p-ethylphenol / 4,6-di-tert-butyl-m-ethylphenol, 32.8 parts of 2,6-di-tert-butyl-p-isopropylphenol), 758.7 parts of 99.66% 2,6-di-tert-butyl-p-isopropylphenol (including 756.1 parts of 2,6-di-tert-butyl-p-isopropylphenol and 2.6 parts of 4,6-di-tert-butyl-2-ethyl-3-methylphenol), 74.3 parts of the second transition fraction (including 48.5 parts of 2,6-di-tert-butyl-p-isopropylphenol and 25.8 parts of 4,6-di-tert-butyl-2-ethyl-3-methylphenol), 102.7 parts of 99.71% 4,6-di-tert-butyl-2-ethyl-3-methylphenol (including 102.4 parts of 4,6-di-tert-butyl-2-ethyl-3-methylphenol, and other 0 .3 parts), 83.7 parts of still residue (including 20.9 parts of 4,6-di-tert-butyl-2-ethyl-3-methylphenol and 62.8 parts of others); among them, 99.66% of 2,6-di-tert-butyl-p-isopropylphenol is directly sold as an antioxidant; the mixture of 6-tert-butyl-3,4-xylenol and 6-tert-butyl-m-isopropylphenol is used for double distillation to prepare 99% 6-tert-butyl-3,4-xylenol and 6-tert-butyl-m-isopropylphenol; the first transition fraction is concentrated to a certain amount and used for separation to obtain m-isopropylphenol, m-ethylphenol, p-ethylphenol and antioxidant 2,6-di-tert-butyl-p-ethylphenol; the second transition fraction is concentrated to a certain amount and used for separation to obtain antioxidant 2,6-di-tert-butyl-p-ethylphenol and 2-ethyl-3-methylphenol;

[0093] Then, concentrated sulfuric acid (the amount of concentrated sulfuric acid added is 1.5% of the weight of each phenolic substance) was added to 1341.9 parts of the above-mentioned 99.64% 6-tert-butyl-3,4-xylenol, 716.1 parts of 99.68% 6-tert-butyl-m-isopropylphenol, and 102.7 parts of 99.71% 4,6-di-tert-butyl-2-ethyl-3-methylphenol, respectively, and the temperature was raised to 200° C. and maintained for 2 hours, then the temperature was lowered to below 100° C., and the mixture was neutralized with liquid alkali to a neutral pH, and then vacuum distilled to obtain 862.6 parts of 99.8% 3,4-xylenol, 480.4 parts of 99.78% m-isopropylphenol, and 50.9 parts of 99.81% 2-ethyl-3-methylphenol, respectively;

[0094] 179 parts of 31% liquid alkali and 350 parts of water were added to the aforementioned 3126.3 parts of phenol oil (containing 76.5 parts of 3,5-dimethylphenol, 83.6 parts of 3-ethyl-5-methylphenol, 19.3 parts of other phenols, etc.) to extract 3,5-dimethylphenol, etc. at an extraction temperature of 80°C. The mixture was stirred for 1 hour, allowed to stand for 1 hour, and separated into layers. The lower layer was the water layer (containing 3,5-dimethylphenol, etc.). The upper layer of phenol oil was washed once with 100 parts of water, allowed to stand for separation, and 2938.5 parts of dephenolized phenol oil were obtained. The mother liquor and the washing liquid were combined, and 70 parts of 98% sulfuric acid were added dropwise under stirring to neutralize to pH=6-7, and then methyl isobutyl ketone was added for extraction twice (200 parts of methyl isobutyl ketone was added each time), and the separated water layer was used for wastewater treatment, and the obtained material layer was added to a distillation kettle for distillation treatment, and 395.2 parts of methyl isobutyl ketone were recovered for reuse, and 67.8 parts of 99.5% 3,5-xylenol and 68 parts of 95.2% 3-ethyl-5-methylphenol were obtained at the same time;

[0095] Afterwards, 68 parts of 95.2% 3-ethyl-5-methylphenol and 140 parts of 95% ethanol were added to a stainless steel crystallization kettle, stirred, heated to 60° C. to dissolve the materials completely, then cooled to 25° C. with circulating water for 2 hours, then cooled to 0° C. with chilled brine for 2 hours, kept warm for 2 hours, centrifuged, and dried at 30° C. with reduced pressure hot water to obtain 57.5 parts of 99.6% 3-ethyl-5-methylphenol, with a crystallization yield of 88.5%.

[0096] S3, alkylation separation of tricresol phenol oil fraction with a distillation range of 231-240°C:

[0097] The tricresol phenol oil fraction with a distillation range of 231 to 240° C. obtained by rectification in step S1 was sampled and analyzed. The results showed that the phenol content was 45.58%, and the composition of phenolic substances (excluding non-phenolic substances) included: 3,4-dimethylphenol 0.87%, p-isopropylphenol 5.67%, m-isopropylphenol 6.89%, 2,3,5-trimethylphenol 28.01%, 3-ethyl-2-methylphenol 0.21%, 3-methyl-5-ethylphenol 38.21%, 4-ethyl-3-methylphenol 15.79%, butylphenol 4.01%, and others 0.24%).

[0098] 14000 parts of the above tricresol oil fraction (containing 6381.2 parts of phenolic substances) and 150 parts of p-toluenesulfonic acid were added to the reactor, stirring was started, the temperature was raised to 90°C, isobutylene was introduced for reaction, the isobutylene introduction time was 6 hours, and then the temperature was kept for reaction for 2 hours. Sample analysis showed that the 2-tert-butyl isopropyl phenol was 0.26%, which was qualified. Then 142.5 parts of liquid caustic soda and 375 parts of water were added to neutralize the mixture, and then vacuum distillation was performed to obtain a 2,3 , 11892.2 parts of phenol oil containing 5-trimethylphenol, 3-methyl-5-ethylphenol, etc., 72.5 parts of 96.6% 6-tert-butyl-3,4-dimethylphenol, 1286 parts of 97.5% 6-tert-butyl-3-methyl-4-ethylphenol, 511.5 parts of 99.1% 2,6-di-tert-butyl-p-isopropylphenol (antioxidant), and 1049 parts of kettle residue (including 626.5 parts of 4,6-di-tert-butyl-m-isopropylphenol and 219.3 parts of tri-tert-butylphenol);

[0099] The above 11892.2 parts of phenol-containing phenol oil are added to a reactor, 4092 parts of 31% liquid caustic soda are added under stirring, the temperature is raised to 60-80°C, stirring for 1 hour after adding the liquid caustic soda, standing for 1 hour, separating the layers, removing the water layer, and then adding 200 parts of water to the phenol oil layer for washing once to obtain 7646.5 parts of dephenolized phenol oil; then the water layer (including washing water) is added to the reactor, stirred, 98% sulfuric acid is added dropwise at about 40°C to neutralize to pH=7, 4000 parts of methyl isobutyl ketone are added while adding sulfuric acid for extraction, stirring for 1 hour after adding the materials, standing for 1 hour, separating the layers, the water layer is extracted once with 1000 parts of methyl isobutyl ketone, separating the layers, and the water layer is removed from the waste water recovery system, The solvent layers were combined and water was separated; the solvent layer was washed once with 200 parts of water, and the separated water jacket was used for the next batch (washing the dephenolized phenol oil after dephenolization), and the solvent layer was added to a high-efficiency distillation tower for atmospheric distillation to obtain 4962 parts of methyl isobutyl ketone for recycling and reuse, and then subjected to vacuum distillation (reflux ratio of 20:1) to obtain 2446.0 parts of crude 3-methyl-5-ethylphenol with a content of 87.1% (including 291.1 parts of 2,3,5-trimethylphenol and 2130.5 parts of 3-methyl-5-ethylphenol) and 1670.5 parts of crude 2,3,5-trimethylphenol with a content of 85.5% (including 1428.3 parts of 2,3,5-trimethylphenol and 225.8 parts of 3-methyl-5-ethylphenol);

[0100] 2446.0 parts of 87.1% crude 3-methyl-5-ethylphenol and 6000 parts of ethanol were added to the reactor for crystallization, stirring was started, the water bath was heated to 60°C to completely dissolve the material, then the temperature was first cooled to 25°C in a cold water bath, and then cooled to 0°C in a salt water bath, the cooling time was 2 hours, and the temperature was kept for 1 hour, filtered, drained, and dried to obtain 1743.3 parts of 98.1% 3-methyl-5-ethylphenol and 6662.4 parts of filtrate; then 1743.3 parts of 98.1% 3-methyl-5-ethylphenol and 2000 parts of ethanol were added to the reactor for recrystallization, stirring was started, the water bath was heated to 70°C to completely dissolve the material, then the temperature was first cooled to 25°C in a cold water bath, and then cooled to 0°C in a salt water bath, the cooling time was 2 hours, and the temperature was kept in a salt water bath -10 ℃, cooling time is 3 hours, heat preservation 1 hour, filtering, draining, drying, obtaining 1531.6 parts of 99.6% 3-methyl-5-ethyl phenol and 2187.1 parts of filtrate (secondary mother liquor can be used for 3-methyl-5-ethyl phenol crude product refining); among them, 6662.4 parts of primary crystallization filtrate are added to a distillation apparatus with a condenser to heat up and recover the solvent, 5899.6 parts are used for recycling, and after evaporation, 698.7 parts of material (containing 3-methyl-5-ethyl phenol 59.54% and 2,3,5-trimethylphenol 40.03%) are obtained, and this part of the material is incorporated into the aforementioned alkali-washed phenol material methyl isobutyl ketone solution, and is used for distilling the crude products of 3-methyl-5-ethyl phenol and 2,3,5-trimethylphenol;

[0101] 1670.5 parts of 85.5% crude 2,3,5-trimethylphenol and 3500 parts of 90-120°C petroleum ether were added to the reactor, stirring was started, the temperature was raised to 90°C in a water bath to completely dissolve the materials, then the temperature was first lowered to 50°C in a cold water bath, then naturally cooled to room temperature, and finally lowered to 10°C in an ice water bath, kept warm for 2 hours, filtered, drained, and air-dried to obtain 1169.9 parts of 96.2% 2,3,5-trimethylphenol and 3930.2 parts of filtrate; then 90.1 parts of 96.2% 2,3,5-trimethylphenol were added to the melt crystallizer, the oil bath was raised to 97°C to dissolve it, then the temperature was slowly lowered to 53°C at 0.5°C / hr, and kept warm for 5 hours to fully crystallize the 2,3,5-trimethylphenol, and then the uncured The first 8.4 parts of the crystallized product (including 28.6% of 3-methyl-5-ethylphenol and 70.9% of 2,3,5-trimethylphenol) were added to the methyl isobutyl ketone solution of the phenolic material washed with alkali to distill the crude products of 3-methyl-5-ethylphenol and 2,3,5-trimethylphenol; then the temperature was raised to 94°C at 0.2°C / hr and kept at this temperature for 2 hours to melt part of the material, and 78.5 parts of 2,3,5-trimethylphenol product with a content of 99.1% were collected, which was a white solid after cooling, and the yield of one melt crystallization was 89.75%; the remaining material was quickly heated and melted, and 3.1 parts of 2,3,5-trimethylphenol with a content of 91.29% were obtained after all the materials were dissolved, which were added to the next batch of crude 2,3,5-trimethylphenol for solvent crystallization;

[0102] 3930.2 parts of the filtrate were added to a distillation apparatus with a condenser and heated to recover 3368.3 parts of the solvent, and after evaporation to dryness, 498.6 parts of material (including 39.5% of 3-methyl-5-ethylphenol and 60.4% of 2,3,5-trimethylphenol) were obtained. This part of the material was added to the methyl isobutyl ketone solution of the phenolic material washed with alkali, and the crude products of 3-methyl-5-ethylphenol and 2,3,5-trimethylphenol were distilled together;

[0103] Add 2 parts of concentrated sulfuric acid to 72.5 parts of 96.6% 6-tert-butyl-3,4-dimethylphenol obtained above, heat to 185°C and maintain for 2 hours, stop the reaction when the content of 6-tert-butyl-3,4-dimethylphenol is 0.19% by gas spectrum detection, then cool the reaction solution to less than 100°C and neutralize it with 2.8 parts of 30% liquid alkali to a neutral pH, then perform vacuum distillation to obtain 45.4 parts of 99.3% 3,4-dimethylphenol, and recover 21 parts of isobutylene for use;

[0104] To 1286 parts of 97.5% 6-tert-butyl-3-methyl-4-ethylphenol obtained above, 25 parts of concentrated sulfuric acid were added, and the temperature was raised to 190°C and maintained for 1.5 hours. When the content of 6-tert-butyl-3-methyl-4-ethylphenol was 0.16% by gas spectrum detection, the reaction was stopped. Then, the reaction solution was cooled to less than 100°C and neutralized with 70 parts of 30% liquid alkali to a neutral pH. Then, 839.5 parts of 99.1% 3-methyl-4-ethylphenol were obtained by vacuum distillation, and 284 parts of isobutylene were recovered for use;

[0105] To the 1049 parts of the still residue obtained above, 10 parts of concentrated sulfuric acid were added, and the temperature was raised to 200°C and maintained for 2 hours. The reaction was stopped when the content of tert-butylphenol was 0.23% as detected by gas spectrum. The reaction solution was then cooled to less than 100°C and neutralized with 28 parts of 30% liquid alkali to a neutral pH. After that, 113.8 parts of 99.6% phenol and 394.5 parts of 99.4% p-isopropylphenol were obtained by vacuum distillation, and 428 parts of isobutylene were recovered for use.

[0106] S4, direct etherification separation of catechol phenol oil fraction with a distillation range of 241-260°C:

[0107] 7321 parts of the catechol phenol oil fraction with a boiling range of 241-260° C. in step S1 (wherein the phenol content is 37.8%, catechol accounts for 78.6% of the phenol, and 5-indanol accounts for 10.3%) are added to the reactor, and 10660 parts of dimethyl carbonate and 2110 parts of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) are added. The mixture is replaced with nitrogen twice, and the mixture is heated to 180° C. and stirred. The mixture is kept warm for 10 hours. The sample is taken for analysis. The result shows that the reaction product contains 0.38% of o-methoxyphenol. The reaction product is then cooled to room temperature and added to a distillation kettle. 7631 parts of dimethyl carbonate are recovered by atmospheric distillation. The remaining material is added The reaction kettle is put into the reactor, and an excess of carbon dioxide gas is introduced for reaction, and the layers are separated. The separated DBU carbonate is heated and decomposed to obtain the catalyst DBU, which is recovered and reused, and the decomposed carbon dioxide is pressurized and recovered for reuse; the remaining material after the catalyst is recovered is added to a distillation tower for vacuum distillation (pressure is -0.098MPa, reflux ratio is 25:1, temperature is 128-132°C), and when the chromatographic analysis shows that the content of dimethyl ether is 98.5%, dimethyl ether is collected, and a total of 2324.4 parts of 99.6% dimethyl ether are collected, and the distillation yield is 85.69%; the distillation is continued to collect 620 parts of 99.2% 5-methoxyindane, and the distillation yield is 90.2%, and the kettle residue is dephenolized phenol oil;

[0108] The above 620 parts of 99.2% 5-methoxyindane and 650 parts of mixed trimethylbenzenes were added to a reactor, the temperature was raised to 120° C., and 47% hydrobromic acid was then added dropwise to react. The methyl bromide gas generated by the reaction was cooled to −10° C. via a condenser and two cold traps and then entered a bromoalkane storage tank (−15° C.). After the reaction was completed, the collection of bromoalkane was stopped. A total of 1,300 parts of 47% hydrobromic acid were added dropwise to collect 388.1 parts of methyl bromide with a yield of 98.3%. The reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 50 parts of water, the layers were separated, and the water layers were combined to obtain 959.3 parts of 28.6% hydrobromic acid solution (which can be used to heat up and recover 47% of the hydrobromic acid for reuse), 635.7 parts of trimethylbenzenes were recovered in a material layer rectification kettle for reuse, and then the remaining material layer was rectified to obtain 521.6 parts of 99.6% 5-indanol.

[0109] S5, direct etherification separation of resorcinol / hydroquinone phenol oil fraction at a distillation range of 261-300°C:

[0110] 14000 parts of the resorcinol / hydroquinone phenol oil fraction with a boiling range of 261-300° C. in step S1 (wherein the phenol content is 31.5%, and in the phenol: 36.92% of resorcinol and 49.66% of hydroquinone) are added to the reactor, and 19650 parts of dimethyl carbonate and 5403 parts of DBU are added, and nitrogen is replaced twice. The mixture is heated to 180° C. and stirred. The reaction is kept warm for 12 hours. The results of sampling and analysis show that the reaction product contains 0.42% of p-methoxyphenol. The reaction product is then cooled to room temperature and added to a distillation kettle. 14070 parts of dimethyl carbonate are recovered by atmospheric distillation. The remaining materials are added to the reactor, and excess carbon dioxide gas is introduced to react. The separated D BU carbonate is heated and decomposed to obtain a catalyst DBU which is recovered and reused, and the decomposed carbon dioxide is pressurized and recovered for reuse; the remaining material after the catalyst is recovered is added to a distillation kettle for vacuum distillation (pressure is -0.098MPa, reflux ratio is 25-30:1, temperature is 135-145°C), and 2282 parts of p-phenylenedimethyl ether are obtained, with a content of 99.4% and a yield of 82.6%; 791.8 parts of intermediate distillates (containing 439.4 parts of p-phenylenedimethyl ether and 348.8 parts of isophenylenedimethyl ether) are collected; 1697.1 parts of 99.2% isophenylenedimethyl ether are collected, with a yield of 82.4%, and 628.6 parts of intermediate products (which can be used to enrich and recover substances such as naphthyl ether) are obtained by further distillation, and the kettle residue is dephenolized phenol oil.

[0111] Example 2

[0112] This embodiment is substantially the same as the embodiment 1, except that: in step S4, the separation method of the catechol phenol oil fraction with a boiling range of 241 to 260° C. is: adding alkali solution for extraction and then performing etherification separation, specifically: adding 7321 parts of the catechol phenol oil fraction with a boiling range of 241 to 260° C. in step S1 (wherein the phenol content is 37.8%, catechol accounts for 78.6% of the phenol, and 5-indanol accounts for 10.3%) in a reactor, and adding 7020 parts of a 31% sodium hydroxide aqueous solution, starting stirring, heating to 60° C. and keeping warm for 2 hours, standing for 1 hour, separating the layers, and removing the water layer; washing once with 400 parts of water, separating the layers, and removing the water to obtain 10152 parts of a water layer (mixed catechol disodium salt aqueous solution) and 4556 parts of dephenolized phenol oil;

[0113] Then add the above 10152 parts of water layer into the reactor, start stirring, start to drop 3430.3 parts of dimethyl sulfate, control the dropping temperature not to exceed 80°C, the dropping time is about 3 hours, after the dropping is completed, keep the reaction at a slight boiling condition for 10 hours, take samples and analyze, the result shows that the reaction product contains 0.15% o-methoxyphenol, then cool the reaction product to 80°C and let it stand for stratification, separate the lower water layer, add 1000 parts of toluene to the water layer for extraction, separate the layers, send the water layer to the wastewater station, mix the toluene layer with the material layer, and send it to In the distillation kettle, 986 parts of toluene were first recovered by atmospheric distillation for reuse, and then vacuum distillation (pressure was -0.098 MPa, reflux ratio was 25:1, temperature was 128-132°C). When the chromatographic analysis showed that the content of o-phthalic ether was 98.5%, o-phthalic ether was collected, and a total of 2364 parts of 99.3% o-phthalic ether were collected, with a yield of 86.8%. The distillation was continued to collect 622.4 parts of 99.5% 5-methoxyindane, with a distillation yield of 91.2%. The kettle residue was recovered (containing a small amount of o-methoxyphenol, etc.).

[0114] Example 3

[0115] This embodiment is substantially the same as the embodiment 1, except that: in step S5, the separation method of the resorcinol / hydroquinone phenol oil fraction with a boiling range of 261-300° C. is as follows: extract with alkali solution and then perform etherification separation, specifically: add 14000 parts of the resorcinol / hydroquinone phenol oil fraction with a boiling range of 261-300° C. in step S1 (wherein the phenol content is 31.5%, and in the phenol: 36.92% of resorcinol and 49.66% of hydroquinone) into a reactor, and add 12803 parts of a 31% sodium hydroxide aqueous solution, start stirring, heat to 60° C. and keep warm for 2 hours, let stand for 1 hour, separate the layers, separate the water layer, wash once with 720 parts of water, separate the layers, and obtain 17895.8 parts of a water layer and 9593 parts of dephenolized phenol oil;

[0116] Then, 17895.8 parts of the water layer was added to the reactor, stirring was started, and 6000 parts of dimethyl sulfate were added dropwise, the dropping temperature was controlled not to exceed 60°C, the dropping time was about 6 hours, and after the dropping was completed, the reaction was kept warm for 12 hours under slightly boiling conditions. Sampling and analysis showed that the reaction product contained 0.13% p-methoxyphenol. Then, the reaction product was cooled to 80°C and allowed to stand for stratification. The lower water layer was separated, and 1000 parts of toluene were added to the water layer for extraction once. The layers were separated, and the water layer was sent to the wastewater station. The toluene layer was mixed with the material layer and sent to the rectification kettle. 986 parts of toluene were recovered by atmospheric distillation for reuse, and then vacuum distillation (pressure was -0.098 MPa, reflux ratio was 20-30:1, temperature was 135-145°C) was performed to obtain 2328.8 parts of 99.2% p-phenylene dimethyl ether, with a yield of 84.1%; 688.7 parts of intermediate fractions (including 391.6 parts of p-phenylene dimethyl ether and 297.1 parts of isophenylene dimethyl ether) were collected; 1745.5 parts of 99.3% isophenylene dimethyl ether were collected, with a yield of 84.7%, and the distillation residues were concentrated and used to extract naphthyl ether and tetrahydronaphthyl ether;

[0117] Add 1000 parts of the above 99.3% isophenyl dimethyl ether and 1000 parts of mixed trimethylol to a reactor, heat to 120° C., then dropwise add 47% hydrobromic acid to react, the methyl bromide gas generated by the reaction is cooled to -10° C. by a condenser and two cold traps and enters a bromoalkane storage tank (-15° C.), after the reaction is completed, stop collecting bromoalkane, dropwise add 3000 parts of 47% hydrobromic acid, collect 1036.2 parts of methyl bromide, and the yield is 97.8%; The reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 50 parts of water, the layers were separated, and the water layers were combined to obtain 2139.8 parts of 23.0% hydrobromic acid solution (which could be used to recover 47% of the hydrobromic acid by heating and reuse), 986.1 parts of trimethylbenzene were recovered in the material layer distillation kettle and reused, and then the remaining material layer was distilled to obtain 388.2 parts of 99.8% 3-methoxyphenol and 382.1 parts of 99.5% resorcinol.

[0118] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0119] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for separating phenolic substances from phenol-containing coal tar, characterized in that: The steps include: S1: firstly carry out atmospheric distillation to remove water from phenol-containing coal tar, and then carry out vacuum distillation to obtain light oil fraction with a distillation range of <170°C, phenol oil fraction with a distillation range of 170-230°C, tricresol phenol oil fraction with a distillation range of 231-240°C, catechol phenol oil fraction with a distillation range of 241-260°C, and resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300°C; wherein the water and the light oil fraction with a distillation range of <170°C are mixed, heated and stirred, and allowed to stand for stratification to obtain dephenolization wastewater and a phenol-containing light oil fraction with a distillation range of <170°C; S2: refining and separating the phenol oil fraction with a distillation range of 170-230° C. in step S1; wherein the phenol oil fraction with a distillation range of 170-230° C. includes a phenol / o-cresol phenol oil fraction with a distillation range of 170-195° C., a mixed cresol phenol oil fraction with a distillation range of 196-208° C., a mixed xylenol phenol oil fraction with a distillation range of 209-222° C., and a 3,4-xylenol / m-isopropylphenol phenol oil fraction with a distillation range of 223-230° C.; S3: alkylating and separating the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1; S4: performing etherification separation on the catechol phenol oil fraction with a distillation range of 241 to 260° C. described in step S1; S5: performing etherification separation on the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. described in step S1.

2. The method for separating phenolic substances from phenol-containing coal tar according to claim 1, characterized in that: In the step S1, the heating and stirring temperature is 50-80°C, and the stirring time is 0.5-1h.

3. The method for separating phenolic substances from phenol-containing coal tar according to claim 1, characterized in that: The specific steps of step S2 include: respectively refining and separating the phenol / o-cresol phenol oil fraction with a distillation range of 170-195° C., the mixed cresol phenol oil fraction with a distillation range of 196-208° C., the mixed xylenol phenol oil fraction with a distillation range of 209-222° C., and the 3,4-xylenol / m-isopropylphenol oil fraction with a distillation range of 223-230° C.

4. The method for separating phenolic substances from phenol-containing coal tar according to claim 1, characterized in that: The specific steps of step S3 include: S31: subjecting the tricresol phenol oil fraction with a distillation range of 231 to 240° C. in step S1 to an alkylation reaction with an olefin under acid catalysis, and then adding liquid alkali to the reaction product, and then subjecting the reaction product to vacuum distillation to obtain phenol-containing phenol oil, 6-tert-butyl-3,4-dimethylphenol, 6-tert-butyl-3-methyl-4-ethylphenol, and 2,6-di-tert-butyl-p-isopropylphenol; S32: Add liquid alkali to the phenol-containing phenol oil obtained in step S31, heat to 60-80°C and stir for 0.5-1h, keep warm and let stand for 1h, separate the layers, remove the water layer, and then add water to the phenol oil layer to wash to obtain dephenolized phenol oil; add sulfuric acid to the water layer to neutralize it to neutrality, and add a non-water-soluble solvent for extraction, separate the layers, recycle the obtained waste water, and distill the obtained solvent layer to obtain crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol; then purify the crude 3-methyl-5-ethylphenol and crude 2,3,5-trimethylphenol respectively to obtain refined 3-methyl-5-ethylphenol and refined 2,3,5-trimethylphenol.

5. The method for separating phenolic substances from phenol-containing coal tar according to claim 4, characterized in that: In the step S31, the acid includes at least one of sulfuric acid, phosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, aminosulfonic acid, strong acid resin, and solid acid; the olefin is an olefin with carbon atoms of C3 to C12; And / or, the water-insoluble solvent includes at least one of a benzene solvent, an ester solvent, an ether solvent, a halogenated alkane solvent, a halogenated aromatic hydrocarbon solvent, and a ketone solvent.

6. The method for separating phenolic substances from phenol-containing coal tar according to claim 1, characterized in that: In step S4, the etherification separation includes any of the following methods: 1) Direct etherification separation: adding a catalyst and an alkylating agent to the catechol phenol oil fraction with a distillation range of 241 to 260° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain a fine product of o-dimethyl ether and a crude product of 5-methoxyindane; then heating and mixing the crude product of 5-methoxyindane with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting methyl bromide; then cooling the remaining reaction liquid to separate the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, separating the layers, the water layer is a hydrobromic acid solution, and the material layer is distilled to recover trimethylbenzene, and a fine product of 5-indanol is obtained; 2) Extraction with alkali solution and then etherification separation: add alkali solution to the catechol phenol oil fraction with a distillation range of 241-260° C. in step S1 to react, wash the reaction product with water, separate the layers to obtain a water layer and dephenolized phenol oil; then add an alkylating agent to the water layer to react, cool the reaction product and let it stand to separate the layers to obtain a water layer and a material layer; extract the water layer with toluene, separate the layers, and recycle the wastewater layer; mix the toluene layer with the material layer, first perform atmospheric distillation to recover toluene, and then perform vacuum distillation to collect dimethyl ether and 5-methoxyindane in sequence.

7. The method for separating phenolic substances from phenol-containing coal tar according to claim 6, characterized in that: In the method 1), the alkylating agent includes at least one of iodoalkanes, chloroalkanes, difatty sulfates, and difatty carbonates; the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo(5,4,0)-7-undecene; And / or, in the method 2), the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.

8. The method for separating phenolic substances from phenol-containing coal tar according to claim 1, characterized in that: In the step S5, the etherification separation includes any of the following methods: 1) Direct etherification separation: adding a catalyst and an alkylating agent to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261 to 300° C. in step S1 to carry out an etherification reaction, recovering the alkylating agent in the reaction product, and subjecting the remaining reaction product to vacuum distillation to obtain p-phenylenedimethyl ether and m-phenylenedimethyl ether; 2) adding alkali solution for extraction and then performing etherification separation: adding alkali solution to the resorcinol / hydroquinone phenol oil fraction with a distillation range of 261-300° C. in step S1 to react, washing the reaction product with water, and layering to obtain a water layer and dephenolized phenol oil; then adding an alkylating agent to the water layer for reaction, cooling the reaction product and standing to layer to obtain a water layer and a material layer; extracting the water layer with toluene, layering, recycling the obtained wastewater layer, mixing the obtained toluene layer with the material layer, firstly performing atmospheric distillation to recover toluene, and then performing vacuum distillation to collect the dimethylbenzene product and the crude isophenylene dimethyl ether; then heating and mixing the crude isophenylene dimethyl ether with mixed trimethylbenzene, and then dropping hydrobromic acid to react, and collecting bromoalkanes; cooling the remaining reaction solution and separating the hydrobromic acid aqueous solution, washing the obtained solvent layer with water, layering, the water layer is a hydrobromic acid solution, and the trimethylbenzene is distilled to recover the trimethylbenzene, and 3-methoxyphenol and resorcinol are obtained.

9. The method for separating phenolic substances from phenol-containing coal tar according to claim 8, characterized in that: In the method 1), the alkylating agent includes at least one of iodoalkanes, chloroalkanes, difatty sulfates, and difatty carbonates; the catalyst includes at least one of sodium methoxide, sodium ethoxide, sodium hydroxide, potassium hydroxide, pyridines, methylaminopyridines, and 1,8-diazabicyclo(5,4,0)-7-undecene; And / or, in the method 2), the alkaline solution includes at least one of a carbonate solution, a bicarbonate solution, and a hydroxide solution.