Method for obtaining dephenolized carbolic oil and phenolic substances by separating m-p-ethylphenol carbolic oil fractions

Abstract

The invention belongs to the field of coalification and synthesis and separation of organic products, and particularly relates to a method for obtaining dephenolized carbolic oil and phenolic substances by separating m-p-ethylphenol carbolic oil fractions. The invention discloses a method for obtaining dephenolized carbolic oil and phenolic substances by separating m-p-ethylphenol carbolic oil fractions, which comprises the following steps: carrying out reduced pressure rectification on phenol-containing coal tar to obtain a carbolic oil fraction at 170-230 DEG C, carrying out reduced pressure rectification on the carbolic oil fraction at 170-230 DEG C to obtain a m-p-ethylphenol carbolic oil fraction at 217-218.5 DEG C, and separating the dephenolized carbolic oil and the phenolic substances under the action of a catalyst to obtain the dephenolized carbolic oil and the phenolic substances. Ethyl is removed from m-ethyl phenol and p-ethyl phenol in the m-p-ethyl phenol carbolic oil fraction, the obtained material mainly comprises phenol and m-p-ethyl phenol dephenolized carbolic oil, the boiling point of the dephenolized carbolic oil obtained after phenolic substances are removed from the m-p-ethyl phenol carbolic oil fraction is 217.5-218 DEG C, the boiling point of the phenol is 183 DEG C, and the phenol and the dephenolized carbolic oil can be easily obtained through rectification. Therefore, the dephenolized carbolic oil can be separated from phenolic substances.

Description

Technical Field

[0001] The invention belongs to the field of coalification and organic product synthesis and separation, and particularly relates to a method for separating a m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances. Background Art

[0002] The phenolic substances in phenol-containing coal tar mainly exist in the 170-300°C fraction, and the volatile phenols mainly exist in the 170-230°C phenol oil fraction. According to the distribution of phenolic substances, the phenol-containing coal tar can be cut into a light oil fraction <170°C, a phenol oil fraction of 170-230°C, a tricresol phenol oil fraction of 227-240°C, and a hydroquinone phenol oil fraction of 240-300°C. The 170-230°C phenol oil fraction is extracted into crude phenol using an alkali dissolution and acid precipitation method or a solvent extraction method. The related art processes crude phenol by refining to obtain various phenol products or mixtures such as phenol, o-cresol, tri-cresol, m-cresol, and xylenol; and then separating the m-cresol, mixed xylenols, and mixed tri-cresols using physical or chemical methods to obtain pure m-cresol, p-cresol, 2,5-xylenol, 2,4-xylenol, 3,5-xylenol, 3,4-tri-cresol, m-ethylphenol, and p-ethylphenol. However, the process is relatively complicated and tedious, and the economic benefits are not very good.

[0003] CN201611113327.5 discloses a method for extracting phenolic compounds from phenol-containing oil. This method uses a composite extractant composed of diethylamine and ethanolamine to extract the phenolic oil. The resulting extractant-phenol solution can be directly distilled and separated, and the extractant entrained in the dephenolized oil can be washed and recovered. The entire process has a high extraction rate, does not produce phenolic wastewater, does not utilize acids or alkalis, and does not corrode equipment. While the recovery rate is high, the process is subject to high operating costs and cumbersome procedures, resulting in poor economic efficiency. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides a method for separating a m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances.

[0005] The method for separating the m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances according to the embodiment of the present invention comprises the following steps:

[0006] (1) subjecting phenol-containing coal tar to vacuum distillation to obtain a phenol oil fraction at 170-230° C., and then subjecting the phenol oil fraction at 170-230° C. to vacuum distillation to obtain a m-ethylphenol oil fraction at 217-218.5° C.; wherein the m-ethylphenol oil fraction contains phenolic materials comprising 1-30 wt % of 2,3-xylenol, 65-98 wt % of m-ethylphenol, 1-30 wt % of 3,5-xylenol, and 0-5 wt % of other materials;

[0007] (2) adding silicon aluminum oxide and zirconium phosphate to the m-ethylphenol oil fraction obtained in step (1) to carry out a reaction, cooling the reaction after completion of the reaction and exhausting the gas, replacing the obtained reaction solution with nitrogen and filtering the solution to obtain a cracking reaction solution, wherein the cracking reaction solution comprises dephenolized oil, phenol, m-ethylphenol, 3,5-dimethylphenol and 2,3-dimethylphenol;

[0008] (3) adding a sulfuric acid solution to the cleavage reaction solution obtained in step (2), and then performing vacuum distillation to obtain phenol and low-phenol dephenolized oil, wherein the low-phenol dephenolized oil includes 3,5-xylenol, 2,3-xylenol, m-p-ethylphenol, and dephenolized oil;

[0009] (4) After mixing the low-phenol dephenolized oil obtained in step (3) with methanol, a silica gel-supported iron alum aluminum oxide catalyst and a hydrogenation catalyst are added to carry out a reaction, and after the reaction is completed, the reaction is filtered, and the obtained filtrate is subjected to vacuum distillation after removing methanol and water to obtain a mixture of dephenolized oil, 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol.

[0010] The advantages and technical effects brought by the method for separating the m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances in the embodiment of the present invention are as follows: 1. The method of the embodiment of the present invention uses relatively cheap phenol-containing coal tar to distill to obtain the m-p-ethylphenol phenol oil fraction, the phenolic substances in the phenol oil are subjected to a catalytic methylation reaction with methanol, and the methylation reaction product, a phenol-containing phenol oil solution, is distilled to obtain m-p-ethylphenol dephenolized phenol oil, 2,3,6-trimethylol, 2,3,5-trimethylol, phenol, 2,6-xylenol and other products, thereby expanding the application field of the m-p-ethylphenol phenol oil fraction, reducing the difficulty of processing phenol-containing coal tar, and realizing the separation of the m-p-ethylphenol phenol oil fraction; 2. The method of the embodiment of the present invention uses a hydrogenation catalyst and hydrogen to remove a small amount of sulfur-containing and nitrogen-containing compounds in the m-p-ethylphenol phenol oil fraction, thereby obtaining 2,3,6-dimethylphenol, 2,3,6-trimethylphenol, and 2,6-dimethylphenol with very low contents of sulfides and nitrogen-containing compounds, which can fully meet the quality indicators of polymerization agents and pharmaceutical-grade intermediates. At the same time, the obtained dephenolized phenol oil does not require hydrogenation pretreatment and can be directly hydrogenated to produce gasoline and diesel, with low hydrogen consumption and a long service life of the hydrogenation catalyst. 3. The catalyst used in the method of the embodiment of the present invention is solid, so it can be fully applied, and substantially no solid waste is generated during the treatment process, making the treatment process green and environmentally friendly.

[0011] In some embodiments, in step (1), the phenol-containing coal tar is phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis;

[0012] And / or, in the step (1), the content of phenolic substances in the 217-218.5° C. para-ethylphenol oil fraction is 40-60 wt %.

[0013] In some embodiments, in step (1), the pressure of the vacuum distillation is -0.05 to -0.1 MPa, and the reflux ratio is 1 to 30:1;

[0014] And / or, in step (1), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 100 to 350.

[0015] In some embodiments, in step (2), the silicon-aluminum oxide comprises silicon dioxide and acidic aluminum oxide, and the mass ratio of silicon dioxide to acidic aluminum oxide is 1:0.01 to 50;

[0016] And / or, in the step (2), the amount of the zirconium phosphate is 1-10% of the mass of the silica-aluminum oxide, and the amount of the silica-aluminum oxide is 1-30% of the mass of the phenolic material in the m-ethylphenol oil fraction;

[0017] And / or, in step (2), the reaction temperature is 300-400° C., the reaction time is 3-8 hours, the pressure gradually rises to 2.0-4.5 MPa during the reaction, sampling and analysis are performed when the pressure remains stable, and the reaction is terminated when the m-p-ethylphenol content is ≤6%;

[0018] And / or, in step (2), the cooling treatment includes cooling to ≤170°C in 0.5 to 1 hour;

[0019] And / or, in step (2), the nitrogen replacement time is 0.5 to 1 hour.

[0020] In some embodiments, in step (3), the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution;

[0021] And / or, in step (3), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1;

[0022] And / or, in the step (3), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

[0023] In some embodiments, in step (4), the molar ratio of phenolic substances to methanol in the low-phenol dephenolized oil is 1:5-10;

[0024] And / or, in the step (4), the amount of hydrogen used is 0.01 to 1 times the mass of the m-p-ethylphenol phenol oil fraction;

[0025] And / or, in step (4), the reaction temperature is 250-350° C., the liquid hourly space velocity required for the reaction is 0.6-1.5 h −1 , and sampling and analysis show that the reaction is completed when the 2,3-dimethylphenol / 3,5-dimethylphenol conversion rate is ≥99% and the 2-methyl-5-ethylphenol content is ≤0.1%;

[0026] And / or, in the step (4), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 10 to 30:1;

[0027] And / or, in the step (4), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

[0028] In some embodiments, in step (4), the size of the silica gel-supported iron sulfate aluminum oxide catalyst is 50-200 mesh;

[0029] And / or, in the step (4), the mass ratio of iron oxide to vanadium oxide and aluminum oxide in the iron vanadium aluminum oxide is 0.5-5:1:0.1-1;

[0030] And / or, in step (4), the hydrogenation catalyst comprises at least one of 1-5% palladium on carbon or Raney nickel;

[0031] And / or, in step (4), the amount of the hydrogenation catalyst is 0.1 to 5% of the mass of the silica gel-supported iron alum aluminum oxide catalyst, and the amount of the silica gel-supported iron alum aluminum oxide catalyst is 0.05 to 0.5 times the mass of the phenolic material in the low-phenol dephenolized oil.

[0032] In some embodiments, the process further includes step (5): adding silicon aluminum oxide and zirconium phosphate to a mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol to carry out a reaction, cooling the mixture after the reaction is completed and discharging the gas, replacing the obtained reaction condensate with nitrogen and filtering the mixture to obtain a cracking reaction liquid, adding a sulfuric acid solution to the cracking reaction liquid, and then performing vacuum distillation to obtain ≥99.5% 2,6-dimethylphenol.

[0033] In some embodiments, in step (5), the amount of zirconium phosphate is 1 to 10% of the mass of the silica-aluminum oxide; the amount of silica-aluminum oxide is 1 to 20% of the mass of the mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol;

[0034] And / or, the silicon-aluminum oxide comprises silicon dioxide and acidic aluminum oxide, and the mass ratio of silicon dioxide to acidic aluminum oxide is 1:0.01-50;

[0035] and / or, the reaction temperature is 250-350° C., the reaction time is 4-10 hours, the pressure is gradually increased to 1.0-3.0 MPa during the reaction, sampling and analysis are performed when the pressure stabilizes, and the reaction is terminated when the ratio of 3-ethyl-2,6-dimethylphenol to 4-ethyl-2,6-dimethylphenol is ≤0.5%;

[0036] And / or, the cooling treatment comprises cooling to ≤170°C within 0.5 to 1 hour;

[0037] And / or, the nitrogen replacement time is 0.5 to 1 hour;

[0038] And / or, the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution;

[0039] And / or, the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1;

[0040] And / or, the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

[0041] In some embodiments, in step (2) and / or step (5), the reaction is carried out in a stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil; the cooling is performed by programmed cooling using the heat transfer oil in the inner coil, and the cooling rate of the heat transfer oil is 100 to 250°C / h. DETAILED DESCRIPTION

[0042] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0043] The method for separating the m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances according to the embodiment of the present invention comprises the following steps:

[0044] (1) subjecting phenol-containing coal tar to vacuum distillation to obtain a phenol oil fraction at 170-230° C., and then subjecting the phenol oil fraction at 170-230° C. to vacuum distillation to obtain a m-ethylphenol oil fraction at 217-218.5° C.; wherein the m-ethylphenol oil fraction contains phenolic materials comprising 1-30 wt % of 2,3-xylenol, 65-98 wt % of m-ethylphenol, 1-30 wt % of 3,5-xylenol, and 0-5 wt % of other materials;

[0045] (2) adding silicon aluminum oxide and zirconium phosphate to the m-ethylphenol oil fraction obtained in step (1) to carry out a reaction, cooling the reaction after completion of the reaction and exhausting the gas, replacing the obtained reaction solution with nitrogen and filtering the solution to obtain a cracking reaction solution, wherein the cracking reaction solution comprises dephenolized oil, phenol, m-ethylphenol, 3,5-dimethylphenol and 2,3-dimethylphenol;

[0046] (3) adding a sulfuric acid solution to the cleavage reaction solution obtained in step (2), and then performing vacuum distillation to obtain phenol and low-phenol dephenolized oil, wherein the low-phenol dephenolized oil includes 3,5-xylenol, 2,3-xylenol, m-p-ethylphenol, and dephenolized oil;

[0047] (4) After mixing the low-phenol dephenolized oil obtained in step (3) with methanol, a silica gel-supported iron alum aluminum oxide catalyst and a hydrogenation catalyst are added to carry out a reaction, and after the reaction is completed, the reaction is filtered, and the obtained filtrate is subjected to vacuum distillation after removing methanol and water to obtain a mixture of dephenolized oil, 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol.

[0048] The method for separating the m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances in the embodiment of the present invention adopts relatively cheap phenol-containing coal tar distillation to obtain the m-p-ethylphenol phenol oil fraction, the phenolic substances in the phenol oil are subjected to a catalytic methylation reaction with methanol, and the methylation reaction product, the phenol-containing phenol oil solution, is distilled to obtain m-p-ethylphenol dephenolized phenol oil, 2,3,6-trimethylol, 2,3,5-trimethylol, phenol, 2,6-xylenol and other products, thereby expanding the application field of the m-p-ethylphenol phenol oil fraction, reducing the difficulty of processing the phenol-containing coal tar, and realizing the separation of the m-p-ethylphenol phenol oil fraction; the method of the embodiment of the present invention makes A small amount of sulfur- and nitrogen-containing compounds in the m-ethylphenol phenol oil fraction can be removed using a hydrogenation catalyst and hydrogen, thereby obtaining 2,3,6-dimethylphenol, 2,3,6-trimethylphenol, and 2,6-dimethylphenol with very low contents of sulfides and nitrogen-containing compounds, which can fully meet the quality indicators of polymerization agents and pharmaceutical-grade intermediates. At the same time, the obtained dephenolized phenol oil does not require hydrogenation pretreatment and can be directly hydrogenated to produce gasoline and diesel, with low hydrogen consumption and a long hydrogenation catalyst life. The method of the embodiment of the present invention uses a solid catalyst and can therefore be fully applied. Basically, no solid waste is generated during the treatment process, and the treatment process is green and environmentally friendly.

[0049] In some embodiments, preferably, in step (1), the phenol-containing coal tar is phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis;

[0050] And / or, in step (1), the content of phenolic substances in the 217-218.5° C. p-ethylphenol phenol oil fraction is 40-60 wt %. More preferably, the content of phenolic substances in the 217-218.5° C. p-ethylphenol phenol oil fraction is 45-55 wt %.

[0051] In some embodiments, preferably, in step (1), the phenolic materials in the m-ethylphenol oil fraction include 5-20 wt% of 2,3-dimethylphenol, 75-90 wt% of m-ethylphenol, 5-15 wt% of 3,5-dimethylphenol and 0-1 wt% of others.

[0052] In some embodiments, preferably, in step (1), the pressure of the vacuum distillation is -0.05 to -0.1 MPa, and the reflux ratio is 1 to 30:1;

[0053] And / or, in step (1), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 100 to 350.

[0054] In some embodiments, preferably, in step (2), the silicon-aluminum oxide comprises silicon dioxide and acidic alumina, and the mass ratio of silicon dioxide to acidic alumina is 1:0.01 to 50. Further preferably, the mass ratio of silicon dioxide to acidic alumina is 1:0.05 to 20.

[0055] In some embodiments, preferably, in step (2), the amount of zirconium phosphate used is 1-10% of the mass of the silica-aluminum oxide, and the amount of the silica-aluminum oxide used is 1-30% of the mass of the phenolic material in the m-ethylphenol oil fraction;

[0056] And / or, in step (2), the reaction temperature is 300-400° C., the reaction time is 3-8 hours, the pressure gradually rises to 2.0-4.5 MPa during the reaction, sampling and analysis are performed when the pressure remains stable, and the reaction is terminated when the m-p-ethylphenol content is ≤6%;

[0057] And / or, in step (2), the cooling treatment includes cooling to ≤170°C in 0.5 to 1 hour;

[0058] And / or, in step (2), the nitrogen replacement time is 0.5 to 1 hour.

[0059] In some embodiments, preferably, in step (3), the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution;

[0060] And / or, in step (3), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1;

[0061] And / or, in step (3), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350. More preferably, the number of theoretical plates of the distillation tower is 250 to 300.

[0062] In some embodiments, preferably, in step (4), the molar ratio of phenolic substances to methanol in the low-phenol dephenolized oil is 1:5-10;

[0063] And / or, in step (4), the amount of hydrogen used is 0.01 to 1 times the mass of the meta-p-ethylphenol phenol oil fraction. Further preferably, the amount of hydrogen used is 0.02 to 0.5 times the mass of the meta-p-ethylphenol phenol oil fraction.

[0064] In some embodiments, preferably, in step (4), the reaction temperature is 250-350° C., the liquid hourly space velocity required for the reaction is 0.6-1.5 h-1, and sampling analysis shows that the reaction is completed when the conversion rate of 2,3-dimethylphenol / 3,5-dimethylphenol is ≥99% and the content of 2-methyl-5-ethylphenol is ≤0.1%;

[0065] And / or, in the step (4), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 10 to 30:1;

[0066] And / or, in step (4), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350. More preferably, the number of theoretical plates of the distillation tower is 250 to 300.

[0067] In some embodiments, preferably, in step (4), the size of the silica gel-supported iron vanadium aluminum oxide catalyst is 50-200 mesh;

[0068] And / or, in the step (4), the mass ratio of iron oxide to vanadium oxide and aluminum oxide in the iron vanadium aluminum oxide is 0.5-5:1:0.1-1;

[0069] In some embodiments, preferably, in step (4), the hydrogenation catalyst comprises at least one of 1-5% palladium carbon or Raney nickel;

[0070] And / or, in step (4), the amount of the hydrogenation catalyst is 0.1-5% of the mass of the silica gel-supported iron alum aluminum oxide catalyst, and the amount of the silica gel-supported iron alum aluminum oxide catalyst is 0.05-0.5 times the mass of the phenolic material in the low-phenol dephenolized oil. Further preferably, the 1-5% palladium carbon and Raney nickel have low activity, and the low activity is controlled by detecting the content of trimethylcyclohexanol in the catalytic methylation reaction solution, requiring the content of trimethylcyclohexanol to be as low as possible.

[0071] In the embodiment of the present invention, a low-activity hydrogenation catalyst is used to hydrogenate some unsaturated substances such as olefins in the meta-p-ethylphenol phenol oil fraction and convert them into stable saturated substances, thereby avoiding the formation of various polymers, facilitating material separation, and having a good decolorization effect, resulting in a product with good color.

[0072] In some embodiments, preferably, in step (4), the reaction is carried out in a reactor, and the reactor includes a fixed bed reactor, a fluidized bed reactor, an ebullient bed reactor, or a transport bed reactor. Further preferably, the reactor is a fixed bed reactor.

[0073] In some embodiments, preferably, the process further comprises step (5): adding silicon aluminum oxide and zirconium phosphate to a mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol to carry out a reaction, cooling the mixture after the reaction is completed and discharging the gas, replacing the obtained reaction condensate with nitrogen and filtering the mixture to obtain a cracking reaction liquid, adding sulfuric acid solution to the cracking reaction liquid, and then performing vacuum distillation to obtain ≥99.5% 2,6-dimethylphenol.

[0074] In some embodiments, preferably, in step (5), the amount of zirconium phosphate used is 1 to 10% of the mass of the silica-aluminum oxide; the amount of silica-aluminum oxide used is 1 to 20% of the mass of the mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol;

[0075] And / or, the silicon-aluminum oxide comprises silicon dioxide and acidic aluminum oxide, and the mass ratio of silicon dioxide to acidic aluminum oxide is 1:0.01-50;

[0076] and / or, the reaction temperature is 250-350° C., the reaction time is 4-10 hours, the pressure is gradually increased to 1.0-3.0 MPa during the reaction, sampling and analysis are performed when the pressure stabilizes, and the reaction is terminated when the ratio of 3-ethyl-2,6-dimethylphenol to 4-ethyl-2,6-dimethylphenol is ≤0.5%;

[0077] And / or, the cooling treatment comprises cooling to ≤170°C within 0.5 to 1 hour;

[0078] And / or, the nitrogen replacement time is 0.5 to 1 hour;

[0079] And / or, the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution;

[0080] And / or, the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1;

[0081] and / or, the vacuum distillation is carried out in a distillation tower having a theoretical plate number of 150 to 350. Further preferably, the mass ratio of the silica to the acidic alumina is 1:0.05 to 20; and / or, the distillation tower has a theoretical plate number of 250 to 300.

[0082] In some embodiments, preferably, in step (2) and / or step (5), the reaction is carried out in a stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil; the cooling is performed by programmed cooling using the heat transfer oil in the inner coil, and the cooling rate of the heat transfer oil is 100 to 250°C / h.

[0083] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0084] Example 1

[0085] Step 1: Distillation of phenol-containing coal tar to obtain 4-ethylphenol phenol oil fraction

[0086] 3,000,000 parts of phenol-containing coal tar from coal pyrolysis of an energy enterprise in Xinjiang (all parts are measured by weight in the examples) were added to the kettle of a distillation tower (100 theoretical plates). 15,162 parts of water were first removed at -0.05 MPa and a reflux ratio of 1:1. Then, vacuum distillation was performed at a pressure of -0.05 to -0.085 MPa and a reflux ratio of 2:1 to obtain 39,987 parts of a light oil fraction with a distillation range of <170°C. Then, vacuum distillation was performed under the conditions of controlling the pressure to -0.085 to -0.099 MPa and a reflux ratio of 5:1 to obtain 414,989 parts of a phenol oil fraction with a distillation range of 170 to 230°C.

[0087] Then, 40,000 parts of the 170-230°C phenol oil fraction are added to a high-efficiency distillation tower (with 250 theoretical plates) and distilled at -0.085-0.095 MPa and a reflux ratio of 15-20:1 to obtain 16,612 parts of a 217-218.5°C m-p-ethylphenol fraction, wherein the phenolic materials account for 49.6 wt %, including 9.6 wt % of 2,3-xylenol, 12.8 wt % of 3,5-xylenol, 41.9 wt % of m-ethylphenol, 35.3 wt % of p-ethylphenol, and 0.4 wt % of others.

[0088] Step 2: Reaction of removing ethyl from phenol oil fraction

[0089] A stainless steel high-pressure reactor (with an external stainless steel condenser and an inner coil) was charged with 500 parts of acidic silica-alumina (the mass ratio of silica to acidic alumina was 1:1, accounting for 12.1% of the mass of the phenolic materials in the m-ethylphenol oil fraction) and 8 parts of zirconium phosphate. 8306 parts of the intermediate p-ethylphenol oil fraction from step 1 (4186 parts of dephenolized oil, 395.4 parts of 2,3-xylenol, 527.4 parts of 3,5-xylenol, 1726.3 parts of m-ethylphenol, 1454.4 parts of p-ethylphenol, and 16.5 parts of others) were added. The reactor was sealed and heated to 350° C. for 5 hours, and the pressure was gradually increased to 2.9 MPa. , take samples for analysis when the pressure is stable, and the reaction is terminated when 5.6% of m-ethylphenol is qualified. Use thermal oil in programmed cooling mode for cooling, and the cooling rate of the thermal oil is 180-190℃ / h. Rapidly cool to 170℃ in 1 hour, and gradually discharge the ethylene released in the reaction; after the gas is discharged, the cracking reaction condensate is slightly cooled and replaced with nitrogen for 0.5 hour, and 7506.8 parts of cracking reaction liquid are obtained by filtration (4144.1 parts of dephenolized oil, 2262.4 parts of phenol, 387.5 parts of 2,3-xylenol, 98.6 parts of m-ethylphenol, 83.1 parts of p-ethylphenol, 516.8 parts of 3,5-xylenol, and 14.3 parts of others), and the solid catalyst is applied.

[0090] The reaction product obtained by filtration was added to the bottom of a distillation tower (theoretical plate number is about 150), 30 parts of 98% sulfuric acid solution was added (the amount of sulfuric acid solution is 0.40% of the mass of the cracking reaction liquid), and the temperature was increased to -0.085 to -0.09 MPa and a reflux ratio of 5 to 10:1, and vacuum distillation was carried out to obtain 2226.1 parts of 99.8% phenol (0.6 ppm sulfide, 0.7 ppm nitrogen), 5203.4 parts of low-phenol dephenolized oil (4115.1 parts of dephenolized oil, 384.8 parts of 2,3-xylenol, 513.2 parts of 3,5-xylenol, 98.1 parts of m-ethylphenol, 82.5 parts of p-ethylphenol, and 9.7 parts of other phenols).

[0091] Step 3: Separation of low-phenol dephenolized oil

[0092] 200 parts of a catalyst prepared by loading iron vanadium aluminum oxide (the mass ratio of iron oxide to vanadium oxide and aluminum oxide is 3:1:0.3) on silica gel (80-120 mesh, the amount of the catalyst of silica gel loaded iron vanadium aluminum oxide is 0.18 times the mass of the phenolic material in the low-phenol dephenolized oil) and 1 part of a 3% palladium carbon catalyst were loaded into a reactor. 5203.4 parts of the low-phenol dephenolized oil obtained in the second step and 1500 parts of methanol (with a molar ratio of 5.3:1 to the phenol in the dephenolized oil) were injected into the reactor through a plunger metering pump. At the same time, hydrogen was introduced in an amount of 150 parts, and the amount of hydrogen was 0.018 times the mass of the m-ethylphenol phenol oil fraction. The reaction was carried out at 250°C and a liquid hourly space velocity of 0.8h-1. Sampling and analysis were performed. 2,3-Dimethyl The conversion rate of phenol / 3,5-xylenol was 99.8%, and 0.07% of 2-methyl-3-ethylphenol was qualified. After passing the test, the product was filtered, the filter cake was reused, and the filtrate was added to a distillation tower (with 250 theoretical plates) to remove 1137.2 parts of methanol and 184.5 parts of water. The product was further distilled under reduced pressure (pressure of -0.09 to -0.095 MPa, reflux ratio of 15 to 20:1) to obtain 4090.4 parts of dephenolized oil, 392.8 parts of 99.6% 2,3,6-trimethylol, 460.6 parts of 99.5% 2,3,5-trimethylol, and 217.6 parts of a mixture of 3-ethyl-2,6-xylenol and 4-ethyl-2,6-xylenol (118.2 parts of 3-ethyl-2,6-xylenol and 99.4 parts of 4-ethyl-2,6-xylenol).

[0093] Step 4: Synthesis of 2,6-dimethylphenol

[0094] A stainless steel high-pressure reactor (with an external stainless steel condenser and an inner coil) was charged with 20 parts of acidic silica-alumina (the mass ratio of silica to acidic alumina was 1:1) and 1 part of zirconium phosphate (the amount of zirconium phosphate was 5% of the mass of the silica-alumina catalyst), and then 217.6 parts of the mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol obtained in step 3 was added. The reactor was sealed and heated to 300°C for 4.5 hours, and the pressure was gradually increased to 2.3-2.4 MPa. a. When the pressure is stable, sampling and analysis are performed. The reaction is terminated with 0.18% 3-ethyl-2,6-dimethylphenol / 4-ethyl-2,6-dimethylphenol. The inner coil is cooled with programmed thermal oil at a cooling rate of 180-190°C / h. The temperature is rapidly lowered to 170°C in 45 minutes, and the ethylene released during the reaction is gradually discharged. After the gas is discharged, the cracking reaction condensate is slightly cooled and replaced with nitrogen for 0.5 hours. The cracking reaction liquid (mainly containing 2,6-dimethylphenol) is filtered and applied as a solid catalyst.

[0095] The reaction product obtained by filtration was added to the bottom of a distillation tower, and 0.8 parts of a 98% sulfuric acid solution was added (the amount of sulfuric acid was 0.45% of the mass of the cracking reaction liquid). Then, the temperature was increased and vacuum distillation was performed (pressure was -0.085 MPa, reflux ratio was 3:1) to obtain 169.9 parts of 99.8% 2,6-dimethylphenol (sulfide 0.4 ppm, nitride 0.6 ppm).

[0096] Example 2

[0097] Step 1: Fraction cutting

[0098] Same as Example 1

[0099] Step 2: Reaction of removing ethyl from phenol oil fraction

[0100] In a stainless steel high-pressure reactor (with an external stainless steel condenser and an inner coil), 500 parts of acidic silica-alumina (the mass ratio of silica to acidic alumina is 1:1) and 8 parts of zirconium phosphate were added, and 8306 parts of the intermediate p-ethylphenol phenol oil fraction from step 1 (4186 parts of dephenolized oil, 395.4 parts of 2,3-xylenol, 527.4 parts of 3,5-xylenol, 1726.3 parts of m-ethylphenol, 1454.4 parts of p-ethylphenol, and 16.5 parts of others) were added. The reactor was sealed and heated to 400°C for 4 hours. The pressure gradually increased to 4.3-4.4 MPa and the pressure stabilized. Sampling and analysis were performed at different times, and the reaction was terminated when 0.11% of m-p-ethylphenol was qualified. The temperature was lowered by using thermal oil in programmed cooling mode at a cooling rate of 230-240°C / h. The temperature was rapidly lowered to 170°C in 1 hour, and the ethylene released in the reaction was gradually discharged. After the gas was discharged, the cracking reaction condensate was slightly cooled and replaced with nitrogen for 0.5 hour, and 7428.5 parts of cracking reaction liquid (4113.9 parts of dephenolized oil, 2401.6 parts of phenol, 385.5 parts of 2,3-xylenol, 514.2 parts of 3,5-xylenol, 2.9 parts of m-p-ethylphenol, and 10.4 parts of others) were obtained by filtration, and the solid catalyst was applied.

[0101] The reaction product obtained by filtration was added to the bottom of a distillation tower (theoretical plate number is about 150), 30 parts of 98% sulfuric acid solution was added (the amount of sulfuric acid solution is 0.40% of the mass of the cracking reaction liquid), and the temperature was increased to -0.085 to -0.09 MPa and a reflux ratio of 5 to 10:1, and vacuum distillation was carried out to obtain 2363.1 parts of 99.9% phenol (0.4 ppm sulfide, 0.5 ppm nitrogen), 5009 parts of low-phenol dephenolized oil (4104.3 parts of dephenolized oil, 382.8 parts of 2,3-xylenol, 510.6 parts of 3,5-xylenol, 2.7 parts of m-p-ethylphenol, and 8.6 parts of other phenols).

[0102] Step 3: Separation of low-phenol dephenolized oil

[0103] 200 parts of a catalyst prepared by loading iron vanadium aluminum oxide (the mass ratio of iron oxide to vanadium oxide and aluminum oxide is 5:1:0.1) on silica gel (80-120 mesh, the amount of the catalyst loaded on silica gel is 0.22 times the mass of the phenolic material in the low-phenol dephenolized oil) and 1 part of a 3% palladium carbon catalyst were loaded into a reactor. 5009 parts of the low-phenol dephenolized oil obtained in the second step and 1800 parts of methanol (with a molar ratio of 7.58:1 to the phenol in the dephenolized oil) were injected into the reactor through a plunger metering pump. Hydrogen (300 parts of hydrogen) was introduced at the same time. The reaction was carried out at 300°C and a liquid hourly space velocity of 1.2 h-1. Sampling and analysis were performed. The conversion rate of 3-xylenol / 3,5-xylenol was 100%, and 0.01% of 2-methyl-3-ethylphenol was qualified. After passing the test, the product was filtered and the filter cake was reused. The filtrate was added to a distillation tower (with 250 theoretical plates) to remove 1526.8 parts of methanol and 130.7 parts of water. The product was further distilled under reduced pressure (with a pressure of -0.09 to -0.095 MPa and a reflux ratio of 15 to 20:1) to obtain 4087.6 parts of dephenolized oil, 427.9 parts of 99.7% 2,3,6-trimethylphenol, 471.6 parts of 99.5% 2,3,5-trimethylphenol, and 8.8 parts of other phenols (including 3.2 parts of 3-ethyl-2,6-xylenol and 4-ethyl-2,6-xylenol).

[0104] Step 4: Synthesis of 2,6-dimethylphenol

[0105] Since the amount of the mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol synthesized in step three is small, it requires a long time to enrich and then deethylate to produce 2,6-dimethylphenol.

[0106] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" 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 expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0107] Although the above embodiments have been shown and described, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those skilled in the art are all within the scope of protection of the present invention.

Claims

1. A method for separating the m-p-ethylphenol phenol oil fraction to obtain dephenolized phenol oil and phenolic substances, characterized in that: The following steps are involved: (1) subjecting phenol-containing coal tar to vacuum distillation to obtain a phenol oil fraction at 170-230° C., and then subjecting the phenol oil fraction at 170-230° C. to vacuum distillation to obtain a m-p-ethylphenol phenol oil fraction at 217-218.5° C.; wherein the m-p-ethylphenol phenol oil fraction comprises 1-30 wt % of 2,3-xylenol, 65-98 wt % of m-p-ethylphenol, 1-30 wt % of 3,5-xylenol, and 0-5 wt % of other materials, calculated as the phenol materials; (2) adding silicon aluminum oxide and zirconium phosphate to the m-ethylphenol oil fraction obtained in step (1) to carry out a reaction, cooling the reaction after completion of the reaction and exhausting the gas, replacing the obtained reaction solution with nitrogen and filtering the solution to obtain a cracking reaction solution, wherein the cracking reaction solution comprises dephenolized oil, phenol, m-ethylphenol, 3,5-dimethylphenol and 2,3-dimethylphenol; (3) adding a sulfuric acid solution to the cleavage reaction solution obtained in step (2), and then performing vacuum distillation to obtain phenol and low-phenol dephenolized oil, wherein the low-phenol dephenolized oil includes 3,5-xylenol, 2,3-xylenol, m-p-ethylphenol, and dephenolized oil; (4) After mixing the low-phenol dephenolized oil obtained in step (3) with methanol, a silica gel-supported iron alum aluminum oxide catalyst and a hydrogenation catalyst are added to carry out a reaction, and after the reaction is completed, the reaction is filtered, and the obtained filtrate is subjected to vacuum distillation after removing methanol and water to obtain a mixture of dephenolized oil, 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol.

2. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1, wherein: In the step (1), the phenol-containing coal tar is phenol-containing coal tar obtained by medium-low temperature coal gasification or medium-low temperature coal pyrolysis; And / or, in the step (1), the content of phenolic substances in the 217-218.5° C. para-ethylphenol oil fraction is 40-60 wt %.

3. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1 or 2, characterized in that: In the step (1), the pressure of the vacuum distillation is -0.05 to -0.1 MPa, and the reflux ratio is 1 to 30:1; And / or, in step (1), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 100 to 350.

4. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1, wherein: In the step (2), the silicon-aluminum oxide comprises silicon dioxide and acidic aluminum oxide, and the mass ratio of the silicon dioxide to the acidic aluminum oxide is 1:0.01 to 50; And / or, in the step (2), the amount of the zirconium phosphate is 1-10% of the mass of the silica-aluminum oxide, and the amount of the silica-aluminum oxide is 1-30% of the mass of the phenolic material in the m-ethylphenol oil fraction; And / or, in step (2), the reaction temperature is 300-400° C., the reaction time is 3-8 hours, the pressure gradually rises to 2.0-4.5 MPa during the reaction, sampling and analysis are performed when the pressure remains stable, and the reaction is terminated when the m-p-ethylphenol content is ≤6%; And / or, in step (2), the cooling treatment includes cooling to ≤170°C in 0.5 to 1 hour; And / or, in step (2), the nitrogen replacement time is 0.5 to 1 hour.

5. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1, wherein: In the step (3), the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution; And / or, in step (3), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1; And / or, in the step (3), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

6. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1, wherein: In the step (4), the molar ratio of phenolic substances to methanol in the low-phenol dephenolized oil is 1:5-10; And / or, in the step (4), the amount of hydrogen used is 0.01 to 1 times the mass of the m-p-ethylphenol phenol oil fraction; And / or, in step (4), the reaction temperature is 250-350° C., the liquid hourly space velocity required for the reaction is 0.6-1.5 h −1 , and sampling and analysis show that the reaction is completed when the 2,3-dimethylphenol / 3,5-dimethylphenol conversion rate is ≥99% and the 2-methyl-5-ethylphenol content is ≤0.1%; And / or, in the step (4), the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 10 to 30:1; And / or, in the step (4), the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

7. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1 or 6, characterized in that: In the step (4), the size of the silica gel-supported iron sulfate aluminum oxide catalyst is 50 to 200 mesh; And / or, in the step (4), the mass ratio of iron oxide to vanadium oxide and aluminum oxide in the iron vanadium aluminum oxide is 0.5-5:1:0.1-1; And / or, in step (4), the hydrogenation catalyst comprises at least one of 1-5% palladium on carbon or Raney nickel; And / or, in step (4), the amount of the hydrogenation catalyst is 0.1 to 5% of the mass of the silica gel-supported iron alum aluminum oxide catalyst, and the amount of the silica gel-supported iron alum aluminum oxide catalyst is 0.05 to 0.5 times the mass of the phenolic material in the low-phenol dephenolized oil.

8. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 1, characterized in that: The method further comprises step (5): adding silicon aluminum oxide and zirconium phosphate to a mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol to carry out a reaction; cooling the mixture after the reaction is completed and discharging the gas; replacing the obtained reaction condensate with nitrogen and filtering the mixture to obtain a cracking reaction liquid; adding a sulfuric acid solution to the cracking reaction liquid; and then performing vacuum distillation to obtain ≥99.5% 2,6-dimethylphenol.

9. The method for obtaining dephenolized phenol oil and phenolic substances by separating the m-p-ethylphenol phenol oil fraction according to claim 8, characterized in that: In the step (5), the amount of the zirconium phosphate is 1 to 10% of the mass of the silica-aluminum oxide; the amount of the silica-aluminum oxide is 1 to 20% of the mass of the mixture of 3-ethyl-2,6-dimethylphenol and 4-ethyl-2,6-dimethylphenol; And / or, the silicon-aluminum oxide comprises silicon dioxide and acidic aluminum oxide, and the mass ratio of silicon dioxide to acidic aluminum oxide is 1:0.01-50; and / or, the reaction temperature is 250-350° C., the reaction time is 4-10 hours, the pressure is gradually increased to 1.0-3.0 MPa during the reaction, sampling and analysis are performed when the pressure stabilizes, and the reaction is terminated when the ratio of 3-ethyl-2,6-dimethylphenol to 4-ethyl-2,6-dimethylphenol is ≤0.5%; And / or, the cooling treatment comprises cooling to ≤170°C within 0.5 to 1 hour; And / or, the nitrogen replacement time is 0.5 to 1 hour; And / or, the concentration of the sulfuric acid solution is 95-98%, and the amount of the sulfuric acid solution is 0.1-0.5% of the mass of the cleavage reaction solution; And / or, the pressure of the vacuum distillation is -0.08 to -0.98 MPa, and the reflux ratio is 3 to 20:1; And / or, the vacuum distillation is carried out in a distillation tower, and the number of theoretical plates of the distillation tower is 150 to 350.

10. The method for separating the m-p-ethylphenol phenol oil fraction according to claim 8 to obtain dephenolized phenol oil and phenolic substances, characterized in that: In step (2) and / or step (5), the reaction is carried out in a stainless steel high-pressure reactor with an external stainless steel condenser and an inner coil; the cooling is performed by programmed cooling using the heat transfer oil in the inner coil, and the cooling rate of the heat transfer oil is 100 to 250°C / h.