Method for purifying phenol-containing material extracted from coal tar

Abstract

The invention provides a method for purifying a phenol-containing material extracted from coal tar, which comprises the following steps: carrying out a series of impurity removal treatment and purification treatment on the phenol-containing material to finally obtain pyridine products, aniline, various fatty acid esters and other products. The method can solve the problems of high fatty acid and pyridine base content, strong smell and serious raw material waste in part of phenolic materials produced in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of purification and comprehensive utilization of phenol-containing coal tar in coal chemical industry, and specifically, the invention relates to a method for purifying phenol-containing materials extracted from coal tar. Background Art

[0002] In some coal pyrolysis processes, the biomass contained in the coal or the added additives are cracked to produce a large amount of organic miscellaneous acids (mainly the various unsaturated fatty acids with long carbon chains in the coal, such as oleic acid, linoleic acid, linolenic acid, ricinoleic acid, etc., and the main products are valeric acid, caproic acid, heptanoic acid, octanoic acid, nonanoic acid, azelaic acid, capric acid, sebacic acid, undecylenic acid, etc.), which are enriched in the wastewater and tar after gasification, condensation or liquefaction (more in the gasification condensation water). These miscellaneous acids have a strong odor, which will corrode equipment and affect product quality in the subsequent production of crude phenol and crude phenol refining, and will have a great impact on the production of wire enamel, phenolic resin, tricresyl phosphate, fungicides, pesticides and medicines.

[0003] Coal tar contains a certain amount of nitrogen-containing and sulfur-containing substances; it also contains a certain amount of gold salts, which mainly exist in the form of carboxylates, among which iron salts basically exist in the form of carboxylates, about 90% of calcium salts exist in the form of carboxylates, there are very few inorganic salts, and the metal content is about 0.03%. Traditional processes do not carry out targeted treatment of tar or phenol-containing phenol oil. There must be a certain amount of nitrogen-containing, sulfur-containing substances and organic acids in the subsequent extracted crude phenol, which will have some negative impacts on the refining of crude phenol. Therefore, it is necessary to carry out desulfurization and denitrification treatments on phenol-containing tar or phenol-containing phenol oil before extracting crude phenol.

[0004] The coal tar produced during coal gasification or pyrolysis contains a large amount of phenolic compounds, which have a certain negative impact on the deep processing of coal tar. Therefore, it is necessary to remove the phenolic substances in the coal tar. The current conventional practice is to distill the coal tar in a tubular furnace to obtain distillation sections with different temperatures, among which 170-230°C is the phenol-containing phenol oil distillation section, which contains a large amount of phenol, o-cresol, m-cresol, xylenol, ethylphenol, and also contains some trimethylol, methylethylphenol, propylphenol, etc. The content of phenolic substances in the phenol-containing phenol oil is basically 30-60%, which has a high extraction value. The composition of phenol-containing coal tar is complex, so there are many substances such as various nitrogen-containing (pyridines, anilines, etc.), sulfur-containing (sulfide, thiophenol, thioether, etc.), and organic acids in the phenol-containing phenol oil. These impurities left in the crude phenol extracted later will seriously affect the quality, smell, and color of the subsequent products, and will also affect the application of phenol products in the fields of medicine, polymer materials, etc., so it is best to remove them before extracting the crude phenol product by solvent method or alkali dissolution method. Compared with reprocessing in the crude phenol refining treatment section, this has low processing cost, good processing effect, and good quality of crude phenol products. It can also produce products such as fatty acids and fatty acid esters with higher value as by-products, and it is easy to achieve continuous operation.

[0005] There is no process for removing impurities such as fatty acids in the traditional treatment process of phenol-containing phenol oil and phenol-containing wastewater, especially the phenol-containing wastewater after gasification and pyrolysis gasification condensation. Therefore, the crude phenol and its refined products contain more or less fatty acids such as butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid and some organic bases such as aniline and pyridine. The total amount of fatty acids in the crude phenol of enterprises such as Xinjiang Qinghua Energy Group Co., Ltd., Xinjiang Xintian Coal Chemical Co., Ltd., and Xinjiang Xinye Energy Chemical Co., Ltd. is generally less than 4%. The small amount of fatty acids contained in phenol, o-cresol, m-cresol, and xylenol obtained by refining crude phenol has little effect on product quality, odor, color, etc., and is basically acceptable to downstream customers; while the content of various fatty acids in the gasified phenol-containing wastewater and tar of Xinjiang Guanghui Energy Co., Ltd. accounts for 8-12% of the crude phenol. Since fatty acids are very corrosive to distillation equipment and have a very bad odor, they seriously affect the quality and performance of subsequent products, which is difficult for downstream customers to accept.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] 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 purifying a phenol-containing material extracted from coal tar.

[0008] The embodiment of the present invention provides a method for purifying phenol-containing materials extracted from coal tar, comprising the following steps:

[0009] (1) adding an inorganic acid to a phenol-containing material, heating and stirring, and then standing to separate the layers, the lower acid water layer is subsequently treated, the upper phenol oil layer is further heated, and sulfate and sulfuric acid are added for heat preservation, followed by cooling and filtering to obtain a filtrate;

[0010] (2) adding alkali solution and phase transfer catalyst dropwise to the filtrate obtained in step (1), heating and stirring, standing for stratification, and subsequently treating the lower fatty acid salt aqueous solution, washing the upper phenol oil layer with sulfuric acid, separating the water, and the remaining phenol oil layer is high-quality phenol oil;

[0011] (3) adding liquid alkali to the acidic water layer obtained in step (1) to neutralize it to a pH of 5 to 7, then adding a non-water-soluble solvent to extract it, then washing it with water to remove all the water, and distilling the obtained solvent layer to obtain aniline; the obtained water layer is further neutralized with alkali solution to a pH of 8 to 10, then adding a non-water-soluble solvent to extract it, removing all the water, and distilling the obtained solvent layer to obtain a pyridine mixture or a pure pyridine product;

[0012] (4) sulfuric acid is added dropwise to the fatty acid salt aqueous solution obtained in step (2) to neutralize the solution to a pH of 4 to 6, and then a non-water-soluble solvent is added for extraction, the water layer obtained by separation is treated to recover the fatty diacid, the obtained solvent layer is heated to remove water and non-water-soluble solvent, and the removed non-water-soluble solvent is recycled; after dehydration, fatty alcohol, acid catalyst and esterification catalyst are added to the remaining solvent layer, the temperature is raised to carry out reflux reaction, and when no obvious water is evaporated in the reaction reflux liquid, the fatty acid is sampled and analyzed and the content is ≤0.5%, the reaction is stopped, the evaporated non-water-soluble solvent is separated and recycled, the remaining reaction reflux liquid is cooled, and then liquid alkali is added to neutralize the solution to a neutral pH, and the solution is allowed to stand to remove the water layer, and the obtained organic layer is washed with water to remove the water layer, thereby obtaining various mono-fatty acid ester solutions; the various mono-fatty acid ester solutions are subjected to rectification treatment to obtain at least one product selected from methyl butyrate, methyl valerate, methyl hexanoate, methyl heptanoate, methyl octanoate, methyl nonanoate, methyl decanoate and methyl undecenoate.

[0013] In some embodiments, the method further comprises: adding sulfuric acid dropwise to the aqueous layer of the recovered fatty diacid to be processed obtained in step (4) to neutralize it to a pH value of ≤2, then adding a non-water-soluble solvent for extraction, separating the layers, sending the aqueous layer to a wastewater treatment workshop, heating the solvent layer to remove water and solvent, reusing the removed solvent, and then adding fatty alcohol, acid catalyst, and esterification catalyst, heating and refluxing to react, to obtain various fatty diacid diester solutions; and then subjecting the fatty diacid diester solutions to distillation treatment to obtain various fatty diacid diester products.

[0014] In some embodiments, in step (1), the inorganic acid comprises at least one of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and aminosulfonic acid, preferably sulfuric acid;

[0015] And / or, the sulfate includes at least one of copper sulfate, copper sulfate aqueous solution, zinc sulfate, and zinc sulfate aqueous solution, preferably copper sulfate or copper sulfate aqueous solution.

[0016] In some embodiments, in step (1), the heating and stirring temperature is 60 to 90° C., and the stirring time is 0.5 to 1 h;

[0017] And / or, the heating temperature is 100-150° C., and the heating time is 1-2 hours;

[0018] And / or, the heat preservation treatment time is 1 to 2 hours.

[0019] In some embodiments, in step (2), the alkali solution includes at least one of a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a potassium hydroxide aqueous solution, and a potassium carbonate aqueous solution, preferably a sodium bicarbonate aqueous solution; and the mass concentration of the alkali solution is 10-33%;

[0020] And / or, the phase transfer catalyst is a quaternary ammonium salt substance or a polyethylene glycol substance;

[0021] Furthermore, the quaternary ammonium salt substance includes at least one of benzyltriethylammonium chloride and tetraethylammonium bromide.

[0022] In some embodiments, in step (3) and / or step (4), the non-water-soluble solvent includes at least one of C4-C8 fatty alcohol solvents, benzene solvents, ether solvents, ketone solvents, ester solvents, and chlorinated alkane solvents.

[0023] In some embodiments, in step (4), the fatty alcohol includes at least one of methanol, ethanol, isopropanol, isobutanol, pentanol, hexanol, ethylene glycol, and glycerol, preferably methanol.

[0024] In some embodiments, in step (4), the acid catalyst includes at least one of an inorganic acid, aminosulfonic acid, benzenesulfonic acid, a strong acidic resin, a strong acidic inorganic oxide, and a strong acidic inorganic salt.

[0025] In some embodiments, in step (4), the esterification catalyst is a pyridine substance or a methylaminopyridine substance.

[0026] The advantages and beneficial effects of the present invention are:

[0027] (1) Phenol-containing materials usually contain impurities such as various organic fatty acids. The purification method of the present invention utilizes the property that the alkalinity of alkali solutions such as sodium bicarbonate is weaker than that of sodium phenol and utilizes solvents to reduce the viscosity of phenol, and adds a phase transfer catalyst, so that the fatty acids in the phenol-containing materials can fully react with alkali solutions such as sodium bicarbonate to generate corresponding sodium fatty acids that are dissolved in the aqueous phase, thereby being separated from the phenol-containing materials, thereby achieving the purpose of removing organic acids from the phenol-containing materials. The fatty acid content in the obtained phenol-containing materials is very low, and such treatment will not form sodium phenol salts to cause the loss of phenol products; and the alkali solutions such as sodium bicarbonate can also react with thiophenols present in some phenol-containing materials, thereby removing thiophenols and removing odors.

[0028] (2) The fatty acid salt aqueous solution obtained in the purification process of the present invention can obtain various fatty acid esters after a series of treatments such as neutralization, extraction, dehydration concentration, esterification, and distillation, thereby achieving the purpose of turning waste into treasure, increasing economic efficiency, and at the same time, the product quality is good and can meet the quality requirements of food additives.

[0029] (3) The present invention can obtain high-quality phenol-containing phenol oil, which can be further refined to obtain petrochemical-grade phenol, refined o-cresol, m-cresol, 2,6-dimethylphenol, xylenol and the like, thereby improving product quality and sales volume, having good economic and social benefits, and providing a guarantee for the application of coal tar products and green coupling phenol extraction. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The embodiment of the present invention provides a method for purifying phenol-containing materials extracted from coal tar, comprising the following steps:

[0035] (1) adding an inorganic acid to a phenol-containing material, heating and stirring, and then standing to separate the layers, the lower acid water layer is subsequently treated, the upper phenol oil layer is further heated, and sulfate and sulfuric acid are added for heat preservation, followed by cooling and filtering to obtain a filtrate;

[0036] (2) adding alkali solution and phase transfer catalyst dropwise to the filtrate obtained in step (1), heating and stirring, standing for stratification, and subsequently treating the lower fatty acid salt aqueous solution, washing the upper phenol oil layer with sulfuric acid, and separating the water, and the remaining phenol oil layer is high-quality phenol oil containing phenol, which can be used for further refining to prepare petrochemical-grade phenol, refined o-cresol, m-cresol, 2,6-dimethylphenol, xylenol and other products;

[0037] (3) adding liquid alkali to the acidic water layer obtained in step (1) to neutralize it to a pH of 5 to 7, then adding a non-water-soluble solvent to extract it, then washing it with water to remove all the water, and distilling the obtained solvent layer to obtain aniline; the obtained water layer is further neutralized with alkali solution to a pH of 8 to 10, then adding a non-water-soluble solvent to extract it, removing all the water, and distilling the obtained solvent layer to obtain a pyridine mixture or a pure pyridine product;

[0038] (4) sulfuric acid is added dropwise to the fatty acid salt aqueous solution obtained in step (2) to neutralize the solution to a pH of 4 to 6, and then a non-water-soluble solvent is added for extraction, the water layer obtained by separation is treated to recover the fatty diacid, the obtained solvent layer is heated to remove water and non-water-soluble solvent, and the removed non-water-soluble solvent is recycled; after dehydration, fatty alcohol, acid catalyst and esterification catalyst are added to the remaining solvent layer, the temperature is raised to carry out reflux reaction, and when no obvious water is evaporated in the reaction reflux liquid, the fatty acid is sampled and analyzed and the content is ≤0.5%, the reaction is stopped, the evaporated non-water-soluble solvent is separated and recycled, the remaining reaction reflux liquid is cooled, and then liquid alkali is added to neutralize the solution to a neutral pH, and the solution is allowed to stand to remove the water layer, and the obtained organic layer is washed with water to remove the water layer, thereby obtaining various mono-fatty acid ester solutions; the various mono-fatty acid ester solutions are subjected to rectification treatment to obtain at least one product selected from methyl butyrate, methyl valerate, methyl hexanoate, methyl heptanoate, methyl octanoate, methyl nonanoate, methyl decanoate and methyl undecenoate.

[0039] It should be noted that in step (1), if the viscosity of the phenol-containing material is relatively high, a water-insoluble solvent with a boiling point below 170° C. may be added to dilute and reduce the viscosity.

[0040] In some embodiments, the method further comprises: adding sulfuric acid dropwise to the aqueous layer of the recovered fatty diacid to be processed obtained in step (4) to neutralize it to a pH value of ≤2, then adding a non-water-soluble solvent for extraction, separating the layers, sending the aqueous layer to a wastewater treatment workshop, heating the solvent layer to remove water and solvent, reusing the removed solvent, and then adding fatty alcohol, acid catalyst, and esterification catalyst, heating and refluxing to react, to obtain various fatty diacid diester solutions; and then subjecting the fatty diacid diester solutions to distillation treatment to obtain various fatty diacid diester products.

[0041] In some embodiments, in step (1), the inorganic acid comprises at least one of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and aminosulfonic acid, preferably sulfuric acid;

[0042] And / or, the sulfate includes at least one of copper sulfate, copper sulfate aqueous solution, zinc sulfate, and zinc sulfate aqueous solution, preferably copper sulfate or copper sulfate aqueous solution.

[0043] Through the synergistic effect of inorganic acid and sulfate, most of the sulfides in the phenol-containing material can be oxidized, thereby achieving the purpose of further purifying the phenol-containing material.

[0044] In some embodiments, in step (1), the heating and stirring temperature is 60 to 90° C., and the stirring time is 0.5 to 1 h;

[0045] And / or, the heating temperature is 100-150° C., and the heating time is 1-2 hours;

[0046] And / or, the heat preservation treatment time is 1 to 2 hours.

[0047] In some embodiments, in step (2), the alkali solution includes at least one of a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a potassium hydroxide aqueous solution, and a potassium carbonate aqueous solution, preferably a sodium bicarbonate aqueous solution; and the mass concentration of the alkali solution is 10-33%;

[0048] And / or, the phase transfer catalyst is a quaternary ammonium salt substance or a polyethylene glycol substance;

[0049] Furthermore, the quaternary ammonium salt substance includes at least one of benzyltriethylammonium chloride and tetraethylammonium bromide.

[0050] The high-quality phenol-containing phenol oil obtained by the present invention has better quality than the commercially available phenol-containing phenol oil that has not been subjected to impurity removal treatment, which can ensure that the quality of the crude phenol and dephenolized phenol oil extracted subsequently will be significantly improved, laying a good foundation for the refining of crude phenol and the hydrogenation of dephenolized phenol oil.

[0051] In some embodiments, in step (3) and / or step (4), the non-water-soluble solvent includes at least one of C4-C8 fatty alcohol solvents, benzene solvents (such as toluene, etc.), ether solvents (such as diisopropyl ether, etc.), ketone solvents (such as methyl isobutyl ketone, etc.), ester solvents (such as isobutyl acetate, etc.), and chloroalkane solvents.

[0052] In some embodiments, in step (4), the fatty alcohol includes at least one of methanol, ethanol, isopropanol, isobutanol, pentanol, hexanol, ethylene glycol, and glycerol, preferably methanol.

[0053] In some embodiments, in step (4), the acid catalyst includes at least one of an inorganic acid (such as sulfuric acid, etc.), aminosulfonic acid, benzenesulfonic acid, a strong acid resin, a strong acid inorganic oxide, and a strong acid inorganic salt.

[0054] In some embodiments, in step (4), the esterification catalyst is a pyridine substance or a methylaminopyridine substance (such as 4-dimethylaminopyridine).

[0055] It should be noted that the phenol-containing materials in the present invention include pre-hydrogenated phenol-containing coal tar, phenol-containing phenol oil obtained by coal gasification coal tar fractionation, phenol-containing phenol oil obtained by coal pyrolysis coal tar fractionation, phenol-containing phenol oil obtained by direct or indirect liquefaction of coal, phenol-containing wastewater generated by coal gasification or coal pyrolysis (phenol-containing wastewater before deacidification and deamination in the phenol-ammonia section of a coal-to-gas enterprise), phenol-containing wastewater generated in coal coking production (including phenol-containing wastewater obtained by washing raw coal gas, phenol-containing wastewater obtained by atmospheric distillation before tar hydrogenation pretreatment obtained by washing raw coal gas and electric capture, etc.), inorganic acid neutralization liquid of phenol sodium salt aqueous solution extracted from phenol-containing coal tar or phenol oil with alkali solution, phenol water obtained by refining crude phenol or distilling phenol products, etc., and non-water-soluble solvent extracts such as crude phenol and phenolic materials containing organic acids, anilines, pyridine bases, etc.

[0056] 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.

[0057] Example 1

[0058] This embodiment provides a method for purifying a phenol-containing material extracted from coal tar, comprising the following steps:

[0059] (1) In an enamel kettle with a water separation device, 100,000 parts of crude phenol containing organic acids (comprising 0.93% valeric acid, 1.03% hexanoic acid, 1.40% heptanoic acid, 0.94% octanoic acid, 1.47% nonanoic acid, 1.86% azelaic acid, 0.65% capric acid, 1.02% sebacic acid, 1.62% undecylenic acid, 1.35% other acids, 0.31% aniline, 0.22% total pyridine base, and 0.06% sulfide) are added, stirring is started, the jacket is heated to 60° C., 100,000 parts of toluene are added, stirred and dissolved for 1 hour, and a toluene solution of crude phenol (i.e., crude phenol after dilution and viscosity reduction) is obtained;

[0060] Subsequently, 900 parts of 50% sulfuric acid were added to the toluene solution of crude phenol, the jacket was heated to 60°C, stirred for 1 hour, allowed to stand for 2 hours, and separated into layers to obtain a lower acid water layer and an upper phenol oil layer, the upper phenol oil layer was washed once with 50 parts of water, separated into layers to obtain an acid water layer and a phenol oil layer, and the two acid water layers were combined to form a total of 1919 parts, which were subsequently processed; the phenol oil layer was further heated to 110°C, and 1000 parts of 31% copper sulfate aqueous solution and 182 parts of 98% sulfuric acid were added dropwise at the same time, the addition time was 1 hour, and the mixture was kept warm for 2 hours, then cooled to 80°C, filtered, and the filtrate was retained in an enamel kettle;

[0061] (2) 40,000 parts of a 20% aqueous sodium bicarbonate solution and 60 parts of benzyltriethylammonium chloride were added dropwise to the filtrate obtained in step (1). After adding, the temperature was raised to 50° C. and stirred for 1 hour. The pH value was measured to be 8. The phenol oil layer was analyzed and no heptanoic acid was found. The analysis was qualified. The mixture was allowed to stand for 2 hours. The fatty acid sodium aqueous layer was separated and placed in a reactor equipped with a reflux dehydration device. The phenol oil layer was washed once with 1,000 parts of water. The layers were separated and the washing liquid was combined with the fatty acid sodium layer to obtain 53,771 parts of a fatty acid sodium aqueous solution (containing 1,120 parts of sodium valerate and hexanoic acid). The upper crude phenol toluene solution layer was washed once with 100 parts of 50% sulfuric acid, and the water was separated. The sampling analysis showed that the crude phenol toluene solution layer contained only 0.0012% pyridine base, which was of good quality and could be used for further refining and extracting high-quality phenol products. Specifically:

[0062] The crude phenol toluene solution was heated, first distilled at normal pressure and then distilled at reduced pressure to recover 98822 parts of toluene, and then 50 parts of 98% sulfuric acid were added, heated to 120°C and stirred for 2 hours to obtain 86253 parts of high-quality crude phenol. The water content was 0.03%, the distillate before 225°C was 51.8mL / 100mL, the neutral oil was 0.2mL / 100mL, the pyridine base was 1.2ppm, the sulfur content was 2.6ppm, and the total fatty acid content was 0.08% by gas chromatography analysis. , naphthalene 0.03%, 2,6-dimethylphenol 0.25%, phenol 51.62%, o-cresol 11.06%, p-cresol 10.63%, m-cresol 15.43%, o-ethylphenol 0.59%, 2,4 / 2,5-dimethylphenol 3.31%, 2,3-dimethylphenol 0.45%, 3,5-dimethylphenol 1.15%, p-ethylphenol 1.31% (including 2,3,6-trimethylphenol), m-ethylphenol 1.10%, 3,4-dimethylphenol 0.56%;

[0063] (3) adding 1919 parts of the acid-water layer obtained in step (1) to a reaction kettle, and dropping 30% of liquid alkali to neutralize to pH=5, then sequentially adding 600 parts and 400 parts of isobutyl acetate to extract twice, washing once with 100 parts of water, removing all the water, and subjecting the obtained material solvent layer to rectification treatment, recovering 988 parts of isobutyl acetate for reuse, and obtaining 286.3 parts of 99.3% aniline; continuing to drop 30% of liquid alkali to neutralize the obtained water layer to pH=9, and then sequentially adding 700 parts and 700 parts of isobutyl acetate to extract twice, removing all the water from the solvent layer, and subjecting the obtained material solvent layer to rectification treatment, recovering 1382 parts of isobutyl acetate for reuse, and obtaining 168.2 parts of 99.0% pyridine;

[0064] (4) 53771 parts of the sodium fatty acid aqueous solution obtained in step (2) are added to a reaction kettle, and 4000 parts of 98% sulfuric acid are added dropwise under stirring to neutralize to pH = 4.5, and then extracted twice with toluene, each time with 5000 parts of toluene, and the obtained toluene layer is washed once with 1000 parts of water, and the water layer is combined for subsequent treatment to recover the fatty diacid, and the toluene layer is heated to remove water and toluene. When most of the toluene is evaporated and the distillate is clear and anhydrous, the distillation is stopped, the temperature is lowered to 60°C, and 5000 parts of methanol, 100 parts of 98% sulfuric acid and 1 part of 4-dimethylaminopyridine are added, and the temperature is raised to reflux for 3 hours. When no obvious water is evaporated in the reaction reflux liquid, a sample is taken for analysis of the fatty acid content of 0.26%, and the reaction is terminated. The 2996 parts of methanol evaporated are distilled and dehydrated and then recycled; after the remaining reaction reflux liquid is cooled to 50°C, 850 parts of 20% sodium bicarbonate are added dropwise to neutralize it until the pH is neutral, and the reaction is continued. The water layer was separated, and the obtained organic layer was washed with a small amount of water to remove the residual methanol. The water layer was separated to obtain various mono-fatty acid ester solutions containing a small amount of toluene; the various mono-fatty acid ester solutions containing a small amount of toluene were added to the kettle of the high-efficiency distillation tower for distillation treatment, and 214.2 parts of 99.2% methyl butyrate, 2068 parts of toluene, 1005 parts of 99.5% methyl valerate, 1089.2 parts of 99.8% methyl hexanoate, 99.6 % methyl heptanoate 1498.7 parts, 99.1% methyl octanoate 976.9 parts, 99.3% methyl nonanoate 1508.1 parts, 99.2% methyl decanoate 627.8 parts, 99.6% methyl undecylenate 1532.2 parts, and kettle residue 412 parts; the yields of the above fatty acid esters are 95.3%, 94.6%, 94.2%, 96.3%, 93.9%, 93.6%, 88.6%, and 94.2% respectively;

[0065] (5) The aqueous layer obtained in the above step (4) for recovering fatty diacids to be treated is added to a reaction kettle, and 880 parts of 98% sulfuric acid is added dropwise under stirring to neutralize to pH = 2, followed by extraction with toluene twice, each time with 3000 parts of toluene. After stratification, the obtained toluene layer is washed once with 500 parts of water, and the aqueous layers are combined and sent to a sewage treatment station; the toluene layer is heated to desolventize and dehydrate, and when most of the toluene is evaporated and the distillate is clear and anhydrous, the distillation is stopped, the temperature is lowered to 60°C, 3500 parts of methanol and 50 parts of 98% sulfuric acid and 0.5 parts of 4-dimethylaminopyridine are added, the temperature is raised to reflux for reaction for 4 hours, and the fatty diacid monomethyl ester content is 0.19% after sampling and analysis, and the reaction is terminated, and 2349 parts of methanol are evaporated and recovered after treatment; the remaining reaction reflux liquid is reduced to 60°C, and the reaction mixture is cooled to 200°C. The mixture was heated to 50°C, and then 430 parts of 10% sodium bicarbonate was added dropwise to neutralize the mixture until the pH value was neutral. The mixture was allowed to stand and the water layer was separated. The obtained ester layer was washed with a small amount of water to remove the residual methanol. The water layer was separated to obtain various fatty diacid diester solutions containing a small amount of toluene. The various fatty diacid diester solutions containing a small amount of toluene were added to the kettle of a high-efficiency distillation tower for distillation treatment to obtain 1286 parts of toluene, 83.5 parts of 99.3% dimethyl adipate, 209.3 parts of 99.2% dimethyl pimelate, 2031.8 parts of 99.5% dimethyl azelaate, 1094.3 parts of 99.6% dimethyl sebacate, and 246 parts of kettle residue. The yields of the above fatty diacid dimethyl esters were 81.3%, 85.8%, 94.6%, and 93.8%, respectively.

[0066] 1000 parts of 99.5% dimethyl azelaic acid and 1000 parts of mixed trimethylbenzene were added to the reactor, the temperature was raised to 120°C, and 47% hydrobromic acid was added dropwise to react. The methyl bromide gas generated by the reaction was cooled to -10°C through a condenser and two cold traps and entered into a bromoalkane storage tank (-15°C). After the reaction was completed, the collection of bromoalkane was stopped. A total of 4760 parts of 47% hydrobromic acid were added dropwise, and 855 parts of methyl bromide were collected, with a yield of 97.3%. The reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 100 parts of water, the layers were separated, the water layers were combined, and 3702 parts of 36.1% hydrobromic acid solution was obtained (which can be used to heat up and recover hydrobromic acid), 983 parts of trimethylbenzene were recovered in the material layer distillation kettle and reused, and then the remaining material layer was distilled to obtain 791.5 parts of 99.8% azelaic acid.

[0067] Example 2

[0068] This embodiment provides a method for purifying a phenol-containing material extracted from coal tar, comprising the following steps:

[0069] (1) In an enameled kettle equipped with a water separator, add 100,000 parts of phenol oil containing organic acids (including 39.6% total phenol content, 0.61% pyridine base, 0.46% aniline (including 0.22% aniline), 0.12% sulfide, 0.37% valeric acid, 0.41% caproic acid, 0.56% heptanoic acid, 0.38% caprylic acid, 0.015% fatty diacid, and 0.38% other acids), start stirring, and add 1610 2681.1 parts of the lower acid water layer (containing 438.1 parts of aniline hydrogen sulfate) are subsequently processed, and the upper phenol oil layer is further heated to 120°C, and 360 parts of 31% copper sulfate aqueous solution and 370 parts of 93% sulfuric acid are added dropwise at the same time, the dropping time is 1 hour, and the temperature is kept for 2 hours, then the temperature is lowered to 80°C, filtered, and the filtrate (containing phenol and phenol oil) is left in the enamel kettle;

[0070] (2) 8550 parts of 20% sodium bicarbonate aqueous solution and 24 parts of benzyltriethylammonium chloride were added dropwise to the filtrate obtained in step (1), and the temperature was raised to 50° C. and stirred for 1 hour. The pH value was measured to be 8. The phenol oil layer was analyzed and no caproic acid was found. The analysis was qualified. The mixture was allowed to stand for 2 hours. The fatty acid sodium aqueous layer was separated and placed in a reactor equipped with a reflux dehydration device. The phenol oil layer was washed once with 400 parts of water, and the layers were separated. The washing liquid was combined with the fatty acid sodium layer to obtain 11149 parts of fatty acid sodium aqueous solution (containing 400 parts of sodium valerate). 48.8 parts, sodium hexanoate 485.6 parts, sodium heptanoate 652.9 parts, sodium octanoate 435.3 parts, other sodium acids 614.6 parts), the upper phenol oil layer was washed once with 100 parts of 50% sulfuric acid, and the water was separated. The sampling analysis showed that it contained 0.05% pyridine base, 0.02% aniline, and 0.02% sulfide, indicating that the phenol oil layer was of relatively high quality, significantly better than the nitrogen and sulfur content of gasified crude phenol (the nitrogen and sulfur content of gasified crude phenol are generally about 0.4% and 0.1%).

[0071] (3) adding 2681.1 parts of the acid-water layer obtained in step (1) to a reaction kettle, and dropwise adding 732 parts of 31% liquid alkali to neutralize to pH=5, then sequentially adding 600 parts and 400 parts of isobutyl acetate to extract twice, washing once with 100 parts of water, removing all the water, subjecting the obtained solvent layer to rectification, recovering 983 parts of isobutyl acetate for reuse, and obtaining 210.4 parts of 99.1% aniline; continuing to dropwise adding 31% liquid alkali to neutralize to pH=9, then sequentially adding 1200 parts and 800 parts of isobutyl acetate to extract twice, removing all the water from the solvent layer, subjecting the obtained material solvent layer to rectification, recovering 1968.5 parts of isobutyl acetate for reuse, and obtaining 477.6 parts of a pyridine mixture;

[0072] (4) 11149 parts of the sodium fatty acid aqueous solution obtained in step (2) (containing 448.8 parts of sodium valerate, 485.6 parts of sodium hexanoate, 652.9 parts of sodium heptanoate, 435.3 parts of sodium octanoate, and 614.6 parts of other sodium acids) were added to a reactor, and 1028 parts of 98% sulfuric acid were added dropwise under stirring to neutralize to pH = 4.5, and then extracted with toluene twice, using 2000 parts of toluene each time, and the toluene layer was washed once with 200 parts of water. The water layer was combined in batches and then prepared into fatty diacid dimethyl ester according to the method of step (5) in the embodiment. The toluene layer was heated to remove water and toluene. After 3756 parts of toluene distillate was distilled out and clarified, the distillation was stopped, the temperature was lowered to 60°C, and 2000 parts of methanol, 40 parts of 98% sulfuric acid and 0.5 parts of 4-dimethylaminopyridine were added, and the temperature was raised to carry out reflux reaction for 3 hours. When no obvious water was evaporated in the reaction reflux liquid, a sample was taken for analysis of the fatty acid content of 0.1 3%, the reaction was terminated, 1650 parts of methanol distilled out was distilled and dehydrated, and then recycled; the remaining reaction reflux liquid was cooled to 50°C, and then 2742 parts of 31% liquid caustic soda was added dropwise to neutralize it to a neutral pH, and the water layer was separated after standing, and the obtained organic layer was washed with a small amount of water to remove a small amount of residual methanol, and the water layer was separated to obtain various mono-fatty acid ester solutions containing a small amount of toluene; the various mono-fatty acid ester solutions containing a small amount of toluene were added to the kettle of the high-efficiency distillation tower. The product was distilled to obtain 286.8 parts of 99.5% methyl butyrate, 192.8 parts of toluene, 400.8 parts of 99.3% methyl valerate, 432.6 parts of 99.7% methyl hexanoate, 596.8 parts of 99.6% methyl heptanoate, 376 parts of 99.4% methyl octanoate and 300.4 parts of still residue. The yields of the above fatty acid esters were 93.9%, 94.8%, 94.3%, 96.1% and 90.2%, respectively.

[0073] 400 parts of the above-mentioned 99.7% methyl caproate and 400 parts of mixed trimethylbenzene 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 entered a bromoalkane storage tank (-15° C.). After the reaction was completed, the collection of bromoalkane was stopped, and a total of 795 parts of 47% hydrobromic acid were added dropwise to collect 282.8 parts of methyl bromide, with a yield of 96.9%. The reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 20 parts of water, the layers were separated, the water layers were combined, and 563 parts of 22.01% hydrobromic acid solution (hydrobromic acid can be further recovered) were obtained. 983 parts of trimethylbenzene were recovered in a material layer rectification kettle for reuse, and the remaining material layer was subsequently distilled to obtain 342.3 parts of 99.9% caproic acid.

[0074] Example 3

[0075] This embodiment provides a method for purifying a phenol-containing material extracted from coal tar, comprising the following steps:

[0076] (1) 90,000 parts of coal gasification phenolic wastewater (containing 5.25% crude phenol, 0.49% total organic acids (0.05% butyric acid, 0.07% valeric acid, 0.18% caproic acid, 0.10% heptanoic acid, 0.06% octanoic acid, 0.03% nonanoic acid, 0.003% fatty diacid), 0.09% naphthalene, 0.06% aniline, 0.02% total pyridine base, 0.01% sulfide) were added to an enameled reactor and allowed to stand for 48 hours. 5,000 parts of the bottom material (mainly wastewater containing slag) were first separated, and 80,000 parts of deoiled wastewater were then added to a storage tank for standby use. The oil on the top was stored separately. Then the above 80,000 parts of deoiled wastewater were added to another reactor with reflux. In the enameled kettle of the water separation device, stirring is started, the jacket is heated to 70°C, and air is introduced to drive out volatile acidic (hydrogen cyanide, hydrogen sulfide, etc.) and alkaline substances (mainly ammonia) for 4 hours, then the temperature is lowered to 50°C, and 10,000 parts of methyl isobutyl ketone are added to the obtained wastewater, stirred and extracted for 1 hour, allowed to stand for 2 hours, separated into layers, the bottom water layer is sent to the wastewater treatment section for treatment, and the upper methyl isobutyl ketone layer of crude phenol is added to the enameled distillation kettle, stirring is started, and 1,000 parts of 50% sulfuric acid are added to the obtained crude phenol methyl isobutyl ketone solution, washed once, and the water is separated. After the obtained acid water layer is concentrated to a certain amount, aniline and pyridine substances can be recovered according to the method of step (3) in Example 1;

[0077] The washed crude phenol methyl isobutyl ketone solution was heated to 115°C, and 145 parts of 31% copper sulfate aqueous solution and 28.7 parts of 96% sulfuric acid were added dropwise for 1 hour, and kept warm for 2 hours, then cooled to 80°C, filtered, and the filtrate (i.e., crude phenol methyl isobutyl ketone solution) was left in an enamel kettle;

[0078] (2) 1490 parts of 20% sodium bicarbonate aqueous solution and 5 parts of benzyltriethylammonium chloride were added dropwise to the filtrate (crude phenol methyl isobutyl ketone solution) obtained in step (1), and the temperature was raised to 50°C and stirred for 1 hour after the addition was completed. The mixture was allowed to stand for 2 hours, and the lower fatty acid sodium aqueous layer was separated and placed in a reactor with a reflux dehydration device. The upper crude phenol methyl isobutyl ketone solution layer was washed once with 1000 parts of water, and the layers were separated. The washing liquid was combined with the fatty acid sodium layer to obtain a fatty acid sodium aqueous solution. Sampling and analysis of the upper crude phenol methyl isobutyl ketone solution layer showed that it contained 0.003% pyridine base and 0.008% aniline. The impurity content was very low, indicating that the phenol oil layer was of good quality and could be used for further refining and extraction of high-quality phenol products. Specifically:

[0079] The crude phenol methyl isobutyl ketone solution was heated and then distilled at normal pressure to recover the methyl isobutyl ketone solvent (adding 3 parts of 98% sulfuric acid). After the methyl isobutyl ketone was completely recovered, 4620 parts of crude phenol were obtained. The water content was 0.02%, the distillate before 225°C was 74.7mL / 100mL, the neutral oil was 0.55mL / 100mL, the pyridine base was 5.1ppm, the aniline was 2.2ppm, the sulfide was 1.8ppm, and the total amount of fatty acids, naphthalene was 0.03%, naphthalene was 0.06%, and 2,6-dimethylphenol was 0.01%. 0.28%, phenol 53.65%, o-cresol 10.46%, p-cresol 10.25%, m-cresol 13.98%, o-ethylphenol 0.48%, 2,4 / 2,5-xylenol 2.26%, 2,3-xylenol 0.44%, 3,5-xylenol 1.15%, p-ethylphenol 1.31% (including 2,3,6-trimethylphenol), m-ethylphenol 1.23%, 3,4-xylenol 0.62%, 3-ethyl-5-methylphenol 0.21%, 2,3,5-trimethylphenol 0.16%;

[0080] (3) 170 parts of sulfuric acid were added dropwise to the sodium fatty acid aqueous solution obtained in step (2) to neutralize it to pH = 4.3, and then extracted twice with diisopropyl ether, each time using 1000 parts, and the water was separated. The aqueous layer was subsequently used to prepare fatty acid dimethyl ester according to the method of step (5) in the embodiment. The diisopropyl ether layer was heated for desolventizing and dehydration. When most of the solvent was evaporated and the distillate was clear and anhydrous, the distillation was stopped, the temperature was lowered to 60°C, and 1000 parts of methanol, 20 parts of sulfuric acid and 2 parts of 4-dimethylaminopyridine were added, and the temperature was raised to reflux for reaction for 2 hours. The fatty acid content was analyzed by sampling and was 0.33%. The reaction was terminated, the evaporated methanol was treated and then used, and the remaining reaction reflux liquid was cooled to 50°C and then 10% bicarbonate was added dropwise. The method comprises the following steps: neutralizing with sodium to a neutral pH value, standing to separate the alkaline water layer, washing the obtained organic layer with a small amount of water to remove the residual methanol, separating the water layer to obtain various fatty acid monoester solutions containing a small amount of diisopropyl ether, and heating to remove the diisopropyl ether; adding the ester solution from which the diisopropyl ether has been removed to the kettle of a high-efficiency distillation tower for distillation treatment to obtain 46 parts of 99.3% methyl butyrate, 63 parts of 99.1% methyl valerate, 160 parts of 99.5% methyl hexanoate, 88 parts of 99.4% methyl heptanoate, 51 parts of 99.6% methyl octanoate, and 25 parts of 99.3% methyl nonanoate in sequence; and the yields of the above fatty acid esters are 87.9%, 86.8%, 88.5%, 87.4%, 86.5%, and 84.6%, respectively.

[0081] Add the above 25 parts of 99.3% methyl nonanoate and 25 parts of mixed trimethylbenzene into a reactor, heat to 130°C, then drop 47% hydrobromic acid to react, the methyl bromide gas generated by the reaction is cooled to -10°C through a condenser and two cold traps and enters a bromoalkane storage tank (-15°C), the reaction is completed, stop collecting bromoalkane, drop 50.2 parts of 47% hydrobromic acid, collect 13.4 parts of methyl bromide, and the yield is 97.2%; then separate the hydrobromic acid aqueous solution after the reaction solution is slightly cooled, wash the solvent layer once with 1 part of water, separate the layers, combine the water layers, and obtain 39.1 parts of 29.89% hydrobromic acid solution (which can be used for further recovery of hydrobromic acid), recover 24.7 parts of trimethylbenzene in the material layer rectification kettle for reuse, and then rectify the remaining material layer to obtain 22.2 parts of 99.6% nonanoic acid.

[0082] 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.

[0083] 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 purifying phenol-containing materials extracted from coal tar, characterized in that: The steps include: (1) adding an inorganic acid to a phenol-containing material, heating and stirring, and then standing to separate the layers, the lower acid water layer is subsequently treated, the upper phenol oil layer is further heated, and sulfate and sulfuric acid are added for heat preservation, followed by cooling and filtering to obtain a filtrate; (2) adding alkali solution and phase transfer catalyst dropwise to the filtrate obtained in step (1), heating and stirring, standing for stratification, and subsequently treating the lower fatty acid salt aqueous solution, washing the upper phenol oil layer with sulfuric acid, separating the water, and the remaining phenol oil layer is high-quality phenol oil; (3) adding liquid alkali to the acidic water layer obtained in step (1) to neutralize it to a pH of 5 to 7, then adding a non-water-soluble solvent to extract it, then washing it with water to remove all the water, and distilling the obtained solvent layer to obtain aniline; the obtained water layer is further neutralized with alkali solution to a pH of 8 to 10, then adding a non-water-soluble solvent to extract it, removing all the water, and distilling the obtained solvent layer to obtain a pyridine mixture or a pure pyridine product; (4) sulfuric acid is added dropwise to the fatty acid salt aqueous solution obtained in step (2) to neutralize the solution to a pH of 4 to 6, and then a non-water-soluble solvent is added for extraction, the water layer obtained by separation is treated to recover the fatty diacid, the obtained solvent layer is heated to remove water and non-water-soluble solvent, and the removed non-water-soluble solvent is recycled; after dehydration, fatty alcohol, acid catalyst and esterification catalyst are added to the remaining solvent layer, the temperature is raised to carry out reflux reaction, and when no obvious water is evaporated in the reaction reflux liquid, a sample is taken for analysis and the fatty acid content is ≤0.5%, the reaction is stopped, the evaporated non-water-soluble solvent is separated and recycled, the remaining reaction reflux liquid is cooled, and then liquid alkali is added to neutralize the solution to a neutral pH, the solution is allowed to stand to separate the water layer, and the obtained organic layer is washed with water to separate the water layer, thereby obtaining various mono-fatty acid ester solutions; The various mono-fatty acid ester solutions are subjected to rectification treatment to obtain at least one product selected from the group consisting of methyl butyrate, methyl valerate, methyl caproate, methyl heptanoate, methyl octanoate, methyl nonanoate, methyl decanoate and methyl undecenoate.

2. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: Also includes: Sulfuric acid is added dropwise to the aqueous layer of the recovered fatty diacid to be processed obtained in step (4) to neutralize it to a pH value of ≤2, and then a non-water-soluble solvent is added for extraction, and the layers are separated. The aqueous layer is sent to a wastewater treatment workshop, and the solvent layer is heated to remove water and solvent. The removed solvent is reused, and then fatty alcohol, acid catalyst, and esterification catalyst are added, and the temperature is raised and refluxed to react to obtain various fatty diacid diester solutions; and then the fatty diacid diester solution is subjected to distillation treatment to obtain various fatty diacid diester products.

3. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (1), the inorganic acid includes at least one of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, and aminosulfonic acid; And / or, the sulfate includes at least one of copper sulfate, copper sulfate aqueous solution, zinc sulfate, and zinc sulfate aqueous solution.

4. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (1), the heating and stirring temperature is 60 to 90° C., and the stirring time is 0.5 to 1 h; And / or, the heating temperature is 100-150° C., and the heating time is 1-2 hours; And / or, the heat preservation treatment time is 1 to 2 hours.

5. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (2), the alkali solution comprises at least one of a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution, a sodium bicarbonate aqueous solution, a potassium hydroxide aqueous solution, and a potassium carbonate aqueous solution, and the mass concentration of the alkali solution is 10 to 33%; And / or, the phase transfer catalyst is a quaternary ammonium salt substance or a polyethylene glycol substance.

6. The method for purifying phenol-containing materials extracted from coal coking according to claim 5, characterized in that: The quaternary ammonium salt substance includes at least one of benzyltriethylammonium chloride and tetraethylammonium bromide.

7. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In step (3) and / or step (4), the non-water-soluble solvent includes at least one of C4-C8 fatty alcohol solvents, benzene solvents, ether solvents, ketone solvents, ester solvents, and chlorinated alkane solvents.

8. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (4), the fatty alcohol includes at least one of methanol, ethanol, isopropanol, isobutanol, pentanol, hexanol, ethylene glycol, and glycerol.

9. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (4), the acid catalyst includes at least one of an inorganic acid, aminosulfonic acid, benzenesulfonic acid, a strong acid resin, a strong acid inorganic oxide, and a strong acid inorganic salt.

10. The method for purifying phenol-containing materials extracted from coal coking according to claim 1, characterized in that: In the step (4), the esterification catalyst is a pyridine substance or a methylaminopyridine substance.