A method for separating a m-cresol phenol oil fraction into a dephenolated phenol oil and phenol

Abstract

The application discloses a method for separating m-p-cresol phenol oil fraction to obtain dephenol phenol oil and phenol, which comprises the following steps: refining phenol-containing coal tar to obtain m-p-cresol phenol oil fraction; removing ethyl in the m-p-cresol phenol oil fraction by catalytic deethylation of o-ethyl phenol to convert into phenol; refining the reaction liquid to obtain 99.5% phenol and pre-dephenol phenol; and catalytically methylating the pre-dephenol phenol in a fixed bed reactor to generate a mixture of 2,4,6-trimethyl phenol and 2,3,6-trimethyl phenol and the like; and refining the mixture to obtain the dephe-nol phenol, refined 2,4,6-trimethyl phenol and 2,3,6-trimethyl phenol in sequence, so as to realize the separation of the m-p-cresol phenol oil fraction.

Description

Technical Field

[0001] This invention relates to a method for separating dephenolized phenolic oil and phenol, specifically a method for separating dephenolized phenolic oil and phenol from m-cresol phenolic oil fraction, belonging to the field of coal chemical and organic product synthesis and separation technology. Background Technology

[0002] Phenolic compounds in phenolic coal tar are mainly found in the 170–300℃ fraction, while volatile phenols are mainly found in the phenolic oil fraction at 170–230℃. In actual production, coal tar enterprises will fractionate phenolic coal tar into light oil, phenolic oil, naphthalene oil, wash oil, anthracene oil, and asphalt fractions according to different distillation ranges. For medium- and low-temperature phenolic coal tar with high phenol content, we can also divide it according to the distribution of phenolic compounds into: <170℃ light oil fraction, 170–230℃ phenolic oil fraction (including phenolic oil fraction containing mixed phenols at 170–185℃, o-cresol oil fraction at 186–195℃, m-p-cresol oil fraction at 196–205℃, and 206–213℃ 2, ... The distillate includes 4-xylenol / 2,5-xylenol oil fraction, 214–221℃ m-p-ethylphenol / 3,5-xylenol oil fraction, 222–226℃ 3,4-xylenol / propylphenol oil fraction (one or more of these), 227–240℃ tricrete oil fraction, and 240–300℃ hydroquinone oil fraction (including 240–250℃ catechol oil fraction, 250–270℃ 5-indanol oil fraction, and 270–300℃ resorcinol / hydroquinone fraction), etc. The residue is medium-temperature coal tar, and the residue can also be hydrogenated to produce oil products. The 214–221℃ m-p-ethylphenol / 3,5-xylenol oil fraction can be further refined to obtain the 217.5–218℃ m-p-ethylphenol oil fraction.

[0003] Phenolic coal tar is first distilled to obtain phenolic oil fractions at 170–230℃. The phenolic oil fractions are then used to extract crude phenol by alkaline dissolution and acid precipitation or solvent extraction. The traditional method for processing crude phenol is to refine it to obtain various phenolic products or mixtures such as phenol, o-cresol, tri-cresol, m-cresol, and xylenol. m-cresol, mixed xylenol, and mixed tri-cresol are then separated by 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. This process is relatively complex and cumbersome, and the economic benefits are not very good. Summary of the Invention

[0004] The purpose of this invention is to provide a method for separating dephenolized phenolic oil and phenol from the m- and p-cresol phenolic oil fraction to solve the above-mentioned problems. This method addresses the issues of traditional extraction of phenolic products from phenolic coal tar, which typically involves: first, distilling the phenolic coal tar to obtain a phenolic oil fraction at 170–230°C; then, using alkaline dissolution and acid precipitation or solvent extraction to extract crude phenol and dephenolized phenolic oil; refining the crude phenol to obtain various phenolic products or mixtures; and then separating mixed phenols (a mixture of phenol and o-cresol), o-cresol fractions (containing 2,6-xylenol), m- and p-cresol, mixed xylenols, mixed tricresols, etc., using physical or chemical methods to obtain phenol, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 2,4-xylenol, 3,5-xylenol, 3,4-tricresol, m-ethylphenol, p-ethylphenol, etc. This process is complex and economically inefficient.

[0005] This invention relates to a method for separating par-cresol oil into dephenolized oil and phenol from a phenol oil fraction, comprising the following steps:

[0006] Step 1: Fractionation of phenolic coal tar to obtain p-cresol oil fraction. The phenolic coal tar fraction is obtained by fractionation to obtain phenolic oil with ≤300℃ after slag removal. The phenolic oil with slag removal is added to the bottom of the distillation column and purified by vacuum distillation to obtain p-cresol oil fraction with a distillation range of 196~205℃.

[0007] Step Two: The reaction to remove ethyl groups from the m-p-cresphenol oil fraction is carried out in a stainless steel high-pressure reactor (with an external stainless steel condenser and internal coil). Acidic silica-alumina oxide and zirconium phosphate (the amount of zirconium phosphate is 1-10% of the mass of the silica-alumina oxide catalyst) are charged into the reactor, followed by the m-p-cresphenol oil fraction obtained in Step One. The reactor is sealed, and the temperature is raised to 300-400℃ for 3-8 hours. The pressure is gradually increased to 2.0-4.5 MPa. When the pressure stabilizes, a sample is taken for analysis. The reaction is terminated when the o-ethylphenol content is ≤0.5%. The internal coil is cooled using a programmed cooling heat transfer oil (the heat transfer oil temperature starts from high). The temperature is gradually and slowly reduced to 100-120℃, then rapidly reduced to ≤170℃ over 0.5-1 hour to gradually remove the ethylene released during the reaction. After the gas is removed, the condensate from the cracking reaction is cooled slightly and purged with nitrogen for 0.5 hours. The pyrolysis reaction liquid (mainly containing phenol oil, phenol, m-p-cresol, etc.) is obtained by filtration. The solid catalyst is reused. The filtered reaction product is added to the bottom of a distillation column, and 95-98% sulfuric acid is added (the amount of sulfuric acid is 0.1-0.5% of the mass of the cracking reaction liquid). Then, the temperature is raised and the pressure is reduced for distillation to obtain ≥99.5% phenol and pre-dephenolized phenol oil (containing m-p-cresol, dephenolized oil, etc.).

[0008] Step 3: Separation of pre-dephenolized phenolic oil. A catalyst (50-200 mesh) prepared by supporting iron alum aluminum oxide on silica gel and an olefin hydrogenation catalyst are packed into a reactor. The phenolic oil obtained in step 2 (calculated by the molar number of phenolic substances) and methanol are mixed at a molar ratio of 1:2-8 and injected into the reactor through a plunger metering pump. Hydrogen gas is simultaneously introduced, and the mixture is kept at 250-350°C with a liquid hourly space velocity (LISH) of 0.6-1.5 h⁻¹. -1 The reaction was carried out under the specified conditions, and samples were taken for analysis. The conversion rate of m-p-cresol was ≥99%, and the content of 2,4 / 2,5-xylenol was ≤30% (excluding non-phenolic substances). After passing the test, the product was filtered, and the filter cake was reused. The filtered reaction product was added to a distillation column to remove methanol and a small amount of water. The remaining material after removing methanol and water was further distilled under reduced pressure to obtain m-p-cresol dephenolized phenolic oil, 99% 2,4 / 2,5-xylenol, 99.5% 2,4,6-tricresol, and 99.5% 2,3,6-tricresol.

[0009] Preferably, in step one, the phenolic coal tar is fractionated to obtain phenolic oil with slag removed at ≤300℃, wherein the phenolic coal tar is obtained from medium-low temperature coal gasification or medium-low temperature coal pyrolysis.

[0010] Preferably, in step one, the phenolic oil containing slag is added to the bottom of the distillation column, and in steps two and three, the filtered reaction product is added to the bottom of the distillation column. The theoretical number of plates in the distillation column is 150 to 350, preferably 250 to 300.

[0011] Preferably, in step one, vacuum distillation yields a cresol oil fraction with a distillation range of 196–205°C. In steps two and three, the fraction is then heated and vacuum distilled. The vacuum distillation is carried out at a pressure of -0.08 to -0.98 MPa and a reflux ratio of 10–30.

[0012] Preferably, in step one, vacuum distillation yields a m-p-cresol phenolic oil fraction with a distillation range of 196–205°C. The m-p-cresol phenolic oil fraction contains 40–60% phenolic substances, preferably 45–55%. The phenolic composition of the m-p-cresol phenolic oil fraction is as follows: o-cresol 0–10%, m-p-cresol 70–95%, o-ethylphenol 5–20%, 2,4-xylenol 0–10%, 2,5-xylenol 0–10%, 2,6-xylenol 0–5%, and other components 0–5%.

[0013] Preferably, in step three, the catalyst (50-200 mesh) prepared by supporting iron alum aluminum oxide on silica gel and the olefin hydrogenation catalyst are loaded into the reactor, and the mass ratio of iron oxide to alum oxide and aluminum oxide in the iron alum aluminum oxidant is 0.5-5:1:0.3-1.

[0014] Preferably, in step three, the catalyst (50-200 mesh) prepared by supporting iron aluminate oxide on silica gel and the olefin hydrogenation catalyst are packed into the reactor. The hydrogenation catalyst is 1-5% palladium on carbon, alkaline-treated aluminum nickel, etc.; the amount used is 0.1-5% of the mass of the iron aluminate oxide catalyst.

[0015] Preferably, in step three, the catalyst (50-200 mesh) prepared by loading iron oxide onto silica gel and the olefin hydrogenation catalyst are packed into a reactor, which is a fixed bed, fluidized bed, boiling bed, conveying bed, or other reactors, with a fixed bed reactor being preferred.

[0016] Preferably, hydrogen gas is introduced simultaneously in step two, and the amount of hydrogen gas used is 0.01 to 1 times the mass of the m-cresol oil fraction, preferably 0.02 to 0.5 times.

[0017] Preferably, in step two, acidic silica-alumina oxide is introduced into a stainless steel high-pressure reactor (with an external stainless steel condenser and an internal coil). The silica-alumina oxide is silicon dioxide and acidic alumina, wherein the mass ratio of silicon dioxide to acidic alumina is 1:0.01-50, preferably 1:0.05-20; the amount of acidic silica-alumina oxide used is 1-20% of the mass of the p-cresol phenol oil fraction in the feedstock.

[0018] Preferably, in step two, the temperature of the heat transfer oil is gradually and slowly reduced from a high temperature to 100-120°C, where the high temperature is 50-70°C lower than the deethylene reaction temperature.

[0019] Beneficial effects:

[0020] 1. This invention uses a dealkylation catalyst to catalyze the deethylation reaction of o-ethylphenol and other compounds in m-p-cresol, and a fixed-bed catalytic methylation reaction to separate m-p-cresol phenol oil fractions. Since a fully usable solid catalyst is used, the catalyst can be reused, and this invention rarely generates solid waste.

[0021] 2. This invention uses inexpensive m-p-cresol phenol oil fraction as raw material. Phenol is obtained through dealkylation of o-ethylphenol and other substances. Distillation yields 99% phenol and partially dephenolized phenol oil. The phenolic substances in the partially dephenolized phenol oil undergo catalytic methylation with methanol. The phenol-containing phenol oil solution from the methylation reaction is then distilled to obtain m-p-cresol dephenolized phenol oil, high-purity 2,4 / 2,5-xylenol, 2,4,6-trimethylphenol, 2,3,6-trimethylphenol, and other products. This expands the application range of m-p-cresol phenol oil fraction, reduces the processing difficulty of phenol-containing coal tar, and achieves the separation of m-p-cresol phenol oil fraction.

[0022] 3. This invention uses a hydrogenation catalyst and hydrogen gas with relatively low activity, which can hydrogenate some unsaturated substances such as olefins in the m- and p-cresol oil fraction, converting them into stable saturated substances, avoiding the formation of various polymers, which is beneficial for material separation and can also play a good decolorization role, resulting in a product with good color.

[0023] 4. This invention uses a small amount of hydrogenation catalyst and hydrogen to remove small amounts of sulfur and nitrogen-containing compounds from the m-crestophenol oil fraction, resulting in 2,4,6-xylenol and 2,3,6-tricrestophenol with very low sulfide and nitrogen-containing compound content, which fully meets the quality indicators of polymerizing agents and pharmaceutical-grade intermediates. At the same time, the dephenolized phenol oil obtained does not require hydrogenation pretreatment and can be directly hydrogenated to produce gasoline and diesel, with low hydrogen consumption and long hydrogenation catalyst life. Detailed Implementation

[0024] Example 1

[0025] Step 1: Phenolic coal tar distillation of p-cresol and phenolic oil fraction. 3,000,000 parts of phenolic coal tar from coal pyrolysis of an energy company in Xinjiang were added to the bottom of a distillation column (100 theoretical plates). First, 15,178 parts of water were removed by dewatering (200 mmHg column). Then, the distillation was carried out under reduced pressure (200-5 mmHg column) to obtain 40,518 parts of light oil fraction with a distillation range of <170℃ and 415,318 parts of phenolic oil fraction with a distillation range of 170-230℃.

[0026] 200,000 parts of the phenol oil fraction at 170–230℃ were then added to a high-efficiency distillation column (250 theoretical plates). Distillation was carried out at 100–50 mmHg and a reflux ratio of 15–20:1 to obtain 69,683 parts of the p-cresol phenol oil fraction at 196–205℃. Sampling and analysis revealed a phenol content of 53.8%, including 9.13% o-cresol, 1.33% 2,6-xylenol, 37.9% m-cresol, 33.83% p-cresol, 7.76% o-ethylphenol, 4.41% 2,4-xylenol, 3.45% 2,5-xylenol, 0.79% o-isopropylphenol, 1.08% 2-ethyl-6-cresol, and 0.32% other components. Simultaneously, 0.87% methyl indene, 0.12% nitrogenous compounds, and 0.07% sulfides were also detected.

[0027] Step Two: The reaction to remove ethyl groups from the p-cresol phenolic oil fraction. In a stainless steel high-pressure reactor (with an external stainless steel condenser and internal coil), 200 parts of acidic silica-alumina oxide (silicon-alumina ratio 1:1), 3 parts of zirconium phosphate, and 20,000 parts of the p-cresol phenolic oil fraction from Step One (9,240 parts of dephenolized oil, 982.4 parts of o-cresol, 143 parts of 2,6-xylenol, 4,078 parts of m-cresol, 3,640 parts of p-cresol, 835 parts of o-ethylphenol, 474.4 parts of 2,4-xylenol, 371.2 parts of 2,5-xylenol, 85 parts of o-isopropylphenol, 116.2 parts of 2-ethyl-6-cresol, and 34.8 parts of other components) were added. The reactor was sealed, heated to 350℃, and reacted for 5 hours, with the pressure gradually increasing to 3.3 MPa. When the pressure stabilized, samples were taken for analysis. The reaction ended when o-ethylphenol was found to be 0.23%. The temperature was then lowered using a programmed cooling mode for heat transfer oil (the temperature of the heat transfer oil was gradually reduced from high to 120℃). The temperature was rapidly reduced to 170℃ within 1 hour, and the ethylene released during the reaction was gradually discharged. After the gas was discharged, the condensate from the cracking reaction was cooled slightly and purged with nitrogen for 0.5 hours. After filtration, 19563.4 parts of cracking reaction liquid were obtained (9193.8 parts of phenol-free oil, 703.4 parts of phenol, 858.4 parts of o-cresol, 141 parts of 2,6-xylenol, 4817.4 parts of m-cresol, 2985.8 parts of p-cresol, 405.2 parts of 2,4-xylenol, 431.6 parts of 2,5-xylenol, 17.2 parts of 2,3-xylenol, and 9.6 parts of other components). The solid catalyst was reused.

[0028] The filtered reaction product was added to the bottom of a distillation column (approximately 200 theoretical plates), and 60 parts of 98% sulfuric acid (the amount of sulfuric acid was 0.30% of the mass of the cracking reaction solution) were added. The column was then subjected to vacuum distillation at -0.085 to -0.09 MPa and a reflux ratio of 15 to 20:1 to obtain 604.4 parts of 99.6% phenol (0.8 ppm sulfides and 0.6 ppm nitrides) and 18697.2 parts of pre-dephenolized phenolic oil (9162.6 parts dephenolized oil, 97.8 parts phenol, 854.2 parts o-cresol, 140.6 parts 2,6-xylenol, 4603 parts m-cresol, 2976.8 parts p-cresol, 404.4 parts 2,4-xylenol, 430.6 parts 2,5-xylenol, 17.6 parts 2,3-xylenol, and 9.6 parts other components).

[0029] Step 3: Separation of pre-dephenolized phenolic oil. 500 parts (50-200 mesh) of catalyst prepared by supporting iron oxide on silica gel and 2 parts (3% palladium on carbon) were loaded into the reactor. 9348.6 parts of pre-dephenolized phenolic oil obtained in Step 2 (4581.3 parts dephenolized oil, 48.9 parts phenol, 427.1 parts o-cresol, 70.3 parts 2,6-xylenol, 2301.5 parts m-cresol, 1488.4 parts p-cresol, 202.2 parts 2,4-xylenol, 215.3 parts 2,5-xylenol, 8.8 parts 2,3-xylenol, and 4.8 parts other components) and 3500 parts methanol (molar ratio of methanol to phenol in the dephenolized oil 2.5:1) were injected into the reactor via a plunger metering pump. Simultaneously, 200 parts of hydrogen gas were introduced. The reactor was maintained at 300°C with a liquid hourly space velocity (LISH) of 0.8 h⁻¹. -1 The reaction was carried out under the specified conditions, and samples were taken for analysis. The conversion rate of p-cresol was 100%, and the 2,4-xylenol / 2,5-xylenol ratio was 10.65%, which was qualified. After passing the test, the mixture was filtered, and the filter cake was reused. The filtrate was added to a distillation column (theoretical trays 250), and 930 parts of methanol and 1378.2 parts of water were removed. 30 parts of 98% sulfuric acid were added, and the mixture was further distilled under reduced pressure to obtain 4601.4 parts of dephenolized phenolic oil (containing 0.68% phenol), 582.4 parts of 99.2% 2,4 / 2,5-xylenol (2,4-xylenol to 2,5-xylenol ratio 0.64:1), 2075.9 parts of 99.1% 2,4,6-trimethylphenol, and 2295.5 parts of 99.5% 2,3,6-trimethylphenol.

[0030] Example 2

[0031] Step 1: Fraction cutting. 3,000,000 parts of phenolic coal tar from the coal pyrolysis of an energy company in Xinjiang were added to the bottom of a distillation column (100 theoretical plates). First, 15,178 parts of water were removed by dewatering (200 mmHg column). Then, the fraction was distilled under reduced pressure (200-5 mmHg column) to obtain 40,518 parts of light oil fraction with a distillation range of <170℃ and 415,318 parts of phenolic oil fraction with a distillation range of 170-230℃.

[0032] 200,000 parts of the phenol oil fraction at 170–230℃ were then added to a high-efficiency distillation column (250 theoretical plates). Distillation was carried out at 100–50 mmHg and a reflux ratio of 15–20:1 to obtain 69,683 parts of the phenol oil fraction at 196–205℃. Sampling and analysis revealed a phenol content of 53.8%, including 9.13% o-cresol, 1.33% 2,6-xylenol, 37.9% m-cresol, 33.83% p-cresol, 7.76% o-ethylphenol, 4.41% 2,4-xylenol, 3.45% 2,5-xylenol, 0.79% o-isopropylphenol, 1.08% 2-ethyl-6-cresol, and 0.32% other compounds. Simultaneously, 0.87% methyl indene, 0.12% nitrogenous compounds, and 0.07% sulfides were also detected.

[0033] Step Two: The reaction to remove ethyl groups from the p-cresol phenolic oil fraction. In a stainless steel high-pressure reactor (with an external stainless steel condenser and internal coil), 200 parts of acidic silica-alumina oxide (silicon-alumina ratio 1:1), 3 parts of zirconium phosphate, and 20,000 parts of the p-cresol phenolic oil fraction from Step One (9,240 parts of dephenolized oil, 982.4 parts of o-cresol, 143 parts of 2,6-xylenol, 4,078 parts of m-cresol, 3,640 parts of p-cresol, 835 parts of o-ethylphenol, 474.4 parts of 2,4-xylenol, 371.2 parts of 2,5-xylenol, 85 parts of o-isopropylphenol, 116.2 parts of 2-ethyl-6-cresol, and 34.8 parts of other components) were added. The reactor was sealed, heated to 350℃, and reacted for 5 hours, with the pressure gradually increasing to 3.3 MPa. When the pressure stabilized, samples were taken for analysis. The reaction ended when o-ethylphenol was found to be 0.23%. The temperature was then lowered using a programmed cooling mode for heat transfer oil (the temperature of the heat transfer oil was gradually reduced from high to 120℃). The temperature was rapidly reduced to 170℃ within 1 hour, and the ethylene released during the reaction was gradually discharged. After the gas was discharged, the condensate from the cracking reaction was cooled slightly and purged with nitrogen for 0.5 hours. After filtration, 19563.4 parts of cracking reaction liquid were obtained (9193.8 parts of phenol-free oil, 703.4 parts of phenol, 858.4 parts of o-cresol, 141 parts of 2,6-xylenol, 4817.4 parts of m-cresol, 2985.8 parts of p-cresol, 405.2 parts of 2,4-xylenol, 431.6 parts of 2,5-xylenol, 17.2 parts of 2,3-xylenol, and 9.6 parts of other components). The solid catalyst was reused.

[0034] The filtered reaction product was added to the bottom of a distillation column (approximately 200 theoretical plates), and 60 parts of 98% sulfuric acid (the amount of sulfuric acid was 0.30% of the mass of the cracking reaction solution) were added. The column was then subjected to vacuum distillation at -0.085 to -0.09 MPa and a reflux ratio of 15 to 20:1 to obtain 604.4 parts of 99.6% phenol (0.8 ppm sulfides and 0.6 ppm nitrides) and 18697.2 parts of pre-dephenolized phenolic oil (9162.6 parts dephenolized oil, 97.8 parts phenol, 854.2 parts o-cresol, 140.6 parts 2,6-xylenol, 4603 parts m-cresol, 2976.8 parts p-cresol, 404.4 parts 2,4-xylenol, 430.6 parts 2,5-xylenol, 17.6 parts 2,3-xylenol, and 9.6 parts other components).

[0035] Step 3: Separation of pre-dephenolized phenolic oil. 500 parts (50-200 mesh) of catalyst prepared by supporting iron oxide on silica gel and 2 parts (3% palladium on carbon) were loaded into the reactor. 9348.6 parts of pre-dephenolized phenolic oil obtained in Step 2 (4581.3 parts dephenolized oil, 48.9 parts phenol, 427.1 parts o-cresol, 70.3 parts 2,6-xylenol, 2301.5 parts m-cresol, 1488.4 parts p-cresol, 202.2 parts 2,4-xylenol, 215.3 parts 2,5-xylenol, 8.8 parts 2,3-xylenol, and 4.8 parts other components) and 6000 parts methanol (molar ratio of methanol to phenol in the dephenolized oil 4.3:1) were injected into the reactor via a plunger metering pump. Simultaneously, hydrogen gas (300 parts hydrogen) was introduced, and the reactor was kept at 250°C with a liquid hourly space velocity (LISH) of 1.0 h⁻¹. -1 The reaction was carried out under the specified conditions, and samples were taken for analysis. The conversion rate of p-cresol was 100%, and the 2,4-xylenol / 2,5-xylenol ratio was 0.18%, which was qualified. After passing the test, the mixture was filtered, and the filter cake was reused. The filtrate was added to a distillation column (theoretical trays 250), and 3218.1 parts of methanol and 1482.3 parts of water were removed. 30 parts of 98% sulfuric acid were added, and the mixture was further distilled under reduced pressure to obtain 4549.7 parts of dephenolized phenolic oil (containing 0.22% phenol), 2471.4 parts of 99.5% 2,4,6-tricresol, and 2189.6 parts of 99.7% 2,3,6-tricresol.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for separating a m-cresol phenol oil fraction to obtain a dephenolated phenol oil and phenol, characterized in that, It comprises the following steps: Step one: phenolic coal tar distillation interval p-cresol phenol oil fraction, phenolic coal tar fraction to obtain ≤300 ℃ deslagging phenolic phenol oil, the deslagging phenolic phenol oil is added to the kettle of the rectifying column, and the vacuum distillation is carried out to obtain the p-cresol phenol oil fraction in the distillation range of 196-205 ℃. Step two: the reaction of removing ethyl in the p-cresol phenol oil fraction, the stainless steel high-pressure reactor is loaded with acidic silicon aluminum oxide and zirconium phosphate, the amount of zirconium phosphate is 1-10% of the mass of the acidic silicon aluminum oxide, then the p-cresol phenol oil fraction obtained in step one is added, the reactor is closed, heated to 300-400 ℃ for 3-8 hours, the pressure is gradually increased to 2.0-4.5 MPa, when the pressure is stable, sampling analysis is carried out, the requirement of o-ethyl phenol is ≤0.5%, the reaction is ended, the heat conduction oil in the inner coil is cooled by program cooling, and the temperature is rapidly reduced to ≤170 ℃ in 0.5-1 hour, the ethylene released in 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 solid catalyst is filtered to obtain the cracking reaction liquid, and the filtered reaction product is added to the kettle of the rectifying column, 95-98% sulfuric acid is added, then the temperature is increased and the vacuum distillation is carried out to obtain ≥99.5% phenol and pre-phenol oil. Step three: separation of the pre-phenol oil, the catalyst prepared by loading iron alumina aluminum oxide on silica gel and olefin hydrogenation catalyst are loaded in the reactor, the pre-phenol oil obtained in the second step and methanol are mixed in a molar ratio of 1:2-8, and then injected into the reactor through a plunger metering pump, while hydrogen is introduced, and the reaction is carried out under the conditions of 250-350 ℃ and liquid hourly space velocity of 0.6-1.5 h-1, sampling analysis is carried out, the conversion rate of p-cresol is ≥99%, and the content of 2,4 / 2,5-dimethyl phenol is ≤30%, which is qualified, then filtered, the filter cake is reused, and the filtered reaction product is added to the rectifying column to remove methanol and a small amount of water; after the methanol and water are removed, the remaining material is continuously subjected to vacuum distillation to obtain p-cresol phenol oil, 99% 2,4 / 2,5-dimethyl phenol, 99.5% 2,4,6-trimethyl phenol and 99.5% 2,3,6-trimethyl phenol.

2. The method for separating par-cresol oil and phenol from m-cresol oil fraction according to claim 1, characterized in that, The phenolic coal tar fraction obtained by distillation in step one is ≤300 ℃ deslagging phenolic phenol oil, and the phenolic coal tar is obtained by medium-low temperature coal gasification and medium-low temperature coal pyrolysis.

3. The method for separating par-cresol oil and phenol from p-cresol oil fraction according to claim 1, characterized in that, In step one, the deslagging phenolic phenol oil is added to the kettle of the rectifying column, and in steps two and three, the filtered reaction product is added to the kettle of the rectifying column, and the theoretical plate number of the rectifying column is 150-350.

4. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol are separated from the m-cresol cresol oil fraction. In steps one, two and three, the vacuum distillation is carried out at a pressure of-0.08 to-0.98 MPa and a reflux ratio of 10-30.

5. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol are separated from the m-cresol cresol oil fraction. In step one, the vacuum distillation is carried out to obtain the p-cresol phenol oil fraction in the distillation range of 196-205 ℃, and the p-cresol phenol oil fraction contains 40-60% phenolic substances.

6. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol is separated from the m-cresol cresol oil fraction. In step one, the vacuum distillation is carried out to obtain the p-cresol phenol oil fraction in the distillation range of 196-205 ℃, and the p-cresol phenol oil fraction contains 40-60% phenolic substances. In step one, the vacuum distillation is carried out to obtain the p-cresol phenol oil fraction in the distillation range of 196-205 ℃, and the p-cresol phenol oil fraction contains 40-60% phenolic substances. Ortho-cresol 0-10%, meta-para-cresol 70-95%, ortho-ethylphenol 5-20%, 2,4-dimethylphenol 0-10%, 2,5-dimethylphenol 0-10%, 2,6-dimethylphenol 0-5%, others 0-5%.

7. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol are separated from the m-cresol cresol oil fraction. The catalyst prepared by loading the iron alum alumina oxide on silica gel in step three, olefin hydrogenation catalyst is packed in the reactor, the mass ratio of iron oxide to alumina oxide, aluminum oxide in the iron alum alumina oxide is 0.5-5:1:0.3-1.

8. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol is separated from the m-cresol cresol oil fraction. The catalyst prepared by loading the iron alum alumina oxide on silica gel in step three, olefin hydrogenation catalyst is packed in the reactor, the hydrogenation catalyst is 1-5% palladium-carbon, nickel-aluminum treated with lye; the amount is 0.1-5% of the mass of the iron alumina catalyst.

9. The process as claimed in claim 1, wherein the m-cresol free cresol oil and phenol is separated from the m-cresol cresol oil fraction. In step two, hydrogen is introduced at the same time, the amount of hydrogen is 0.01-1 times the mass of the meta-para-cresol creosote fraction, in step three, the catalyst prepared by loading the iron alumina oxide on silica gel, olefin hydrogenation catalyst is packed in the reactor, the reactor is a fixed bed, fluidized bed, boiling bed, transport bed reactor.

10. The process as claimed in claim 1, wherein the m-cresol free creosote and phenol are separated from the m-cresol creosote fraction. In step two, the acid silicon aluminum oxide is loaded in the stainless steel high-pressure reactor, the acid silicon aluminum oxide is silicon dioxide and acid alumina, the mass ratio of silicon dioxide to acid alumina is 1:0.01-50, the amount of acid silicon aluminum oxide is 1-20% of the mass of the raw material meta-para-cresol creosote fraction.