Method for synthesizing phenolic resin from mixed phenol containing 2, 4, 6-tricresol

Abstract

The invention belongs to the technical field of organic synthesis and separation, and particularly relates to a method for synthesizing phenolic resin from mixed phenol containing 2, 4, 6-tricresol. The invention provides a method for synthesizing phenolic resin from mixed phenol containing 2, 4, 6-tricresyl, which specifically comprises the following steps: adding a first phenol component, a phenolic material containing 2, 4, 6-tricresyl, formaldehyde and a catalyst into a reactor, starting stirring, heating, carrying out heat preservation reaction, sampling and analyzing that p-ethyl phenol is less than or equal to 5% and is qualified, heating, decompressing and dehydrating, and evaporating out unreacted 2, 4, 6-tricresyl to obtain a second phenol component containing 2, 4, 6-tricresyl; adding 2, 3, 6-tricresol, p-ethyl phenol, water and the like, and dehydrating to obtain phenolic resin; adding a catalyst into the steamed material, heating to completely react unreacted p-ethyl phenol (when formaldehyde in the steamed material is insufficient, a small amount of formaldehyde can be supplemented), adding a non-water-soluble solvent for extraction and layering, and treating a water layer in a wastewater treatment workshop; and adding an oil layer into a rectifying tower, and rectifying to obtain 99% 2, 4, 6-tricresol.

Description

Technical Field

[0001] This invention belongs to the technical field of organic synthesis and separation, and specifically relates to a method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol. Background Technology

[0003] Phenolic resin is a synthetic resin formed by the condensation polymerization of phenol and formaldehyde under the action of a catalyst. Due to its excellent high-temperature resistance, chemical resistance, and bonding strength, it has wide applications in refractory materials, friction materials, and packaging materials. However, the high price of raw material phenol keeps production costs high.

[0004] Therefore, how to prepare phenolic resins using mixed powders containing 2,4,6-trimethylphenol has attracted increasing attention from those skilled in the art. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention provide a method for synthesizing phenolic resins from a mixture of phenols containing 2,4,6-trimethylphenol.

[0006] The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to embodiments of the present invention includes the following steps:

[0007] (1) Add a portion of phenolic material containing 2,4,6-trimethylphenol, a portion of aldehydes, and a first catalyst to a polymerization reactor, start stirring, and heat to 60-105℃ for 1-6 hours. Add the remaining phenolic material containing 2,4,6-trimethylphenol and the remaining aldehydes dropwise over 1-4 hours. After adding, keep warm for 1-6 hours and take a sample for analysis. The p-ethylphenol content is ≤5% and qualified. The phenolic material containing 2,4,6-trimethylphenol includes: 10-60 wt% m-p-ethylphenol, 10-90 wt% 2,4,6-trimethylphenol, 10-30 wt% 3,5-xylenol, 0-10 wt% 2,4 / 2,5-methylethylphenol, and 0-10 wt% 3,4-xylenol. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the time is 2-5 hours. The final pressure is controlled at -0.075--0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes. (3) Gradually increase the vacuum to -0.09 to -0.1 MPa within 1 to 2 hours, while further heating and dehydrating. When the temperature of the material in the kettle reaches 80 to 230°C and no liquid distills out, keep it warm for 0.5 to 1 hour, stop dehydration, release the vacuum with nitrogen, and cool the material while it is hot under nitrogen protection to obtain phenolic resin.

[0008] The advantages and technical effects of the method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol in this invention are as follows: 1. The method of this invention utilizes the characteristic that 2,4,6-trimethylphenol reacts very little with aldehydes, allowing m-ethylphenol, p-ethylphenol, 3,5-xylenol, 3,4-xylenol, etc., containing 2,4,6-trimethylphenol to react completely with formaldehyde. This method uses some inexpensive phenolic materials containing 2,4,6-trimethylphenol to replace phenol in the production of phenolic resin, while simultaneously producing 99% 2,4,6-trimethylphenol, resulting in better economic benefits. The invention provides several advantages, including expanding the application scope and market size of phenolic materials containing 2,4,6-trimethylphenol; 2. The method of this invention, which uses m-p-ethylphenol containing 2,4,6-trimethylphenol to replace phenol in the production of phenolic resin, can effectively solve the market problem of m-p-ethylphenol containing 2,4,6-trimethylphenol generated from the refining of 100,000 to 200,000 tons of crude phenol produced in newly built coal gasification, coal pyrolysis, and coal liquefaction industries, and reduce the production cost of phenolic resin. This can contribute to the healthy and orderly development of the coal gasification, coal liquefaction, and coal pyrolysis industries.

[0009] In some embodiments, in step (1), a first phenolic component is added to the polymerization reactor. The first phenolic component includes at least one of m-cresol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3,5-xylenol, phenol, or 3-ethyl-5-cresol. The amount of the first phenolic component is 0.1% to 200% of the mass of the phenolic material containing 2,4,6-trimethylphenol. And / or, in step (1), the phenolic material containing 2,4,6-trimethylphenol is obtained by distillation of crude phenol extracted from coal coking crude phenol, medium-low temperature coal gasification crude phenol, or phenolic coal tar extracted by coal pyrolysis.

[0010] In some embodiments, in step (1), the aldehydes include at least one of paraformaldehyde, formaldehyde, or acetaldehyde; The amount of aldehydes used is 0.8 to 2.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-dimethylphenol, and 3,4-dimethylphenol.

[0011] In some embodiments, in step (1), a portion of the phenolic material containing 2,4,6-trimethylphenol is 0 to 100 wt% of the total phenolic material, and a portion of the aldehyde is 0 to 100 wt% of the total aldehyde.

[0012] In some embodiments, in step (1), the first catalyst is an acidic catalyst, which includes at least one of oxalic acid, formic acid, phosphoric acid, hydrochloric acid, aminosulfonic acid or benzenesulfonic acid; The amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials.

[0013] In some embodiments, in step (1), the first catalyst is an alkaline catalyst, which includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water; the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials. Step (2) involves adding glacial acetic acid or formic acid to neutralize the pH to 6-7 after the reaction is complete, gradually increasing the vacuum to -0.07 to -0.1 MPa over 0.5-1 hours to begin dehydration. When the dehydration rate slows down or the temperature drops to around 70-75°C, heating is used to continue dehydration, controlling the final liquid temperature at 70-90°C until the water level reaches the required value. A sample is then taken for analysis to determine the moisture content of the material to be ≤5%. Step (3) involves adding ethylene glycol to the polymerization reactor, stirring it evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, and adding ethanol to adjust the viscosity to 10-30 Pa·s according to the requirements of different products. After the viscosity reaches the required level, the temperature is lowered to 50°C and the material is discharged. The amount of ethylene glycol used is 1-10% of the mass of the phenolic raw materials.

[0014] In some embodiments, the method further includes step (4): adding a second catalyst and aldehydes to the distilled material, heating to 80-105°C and refluxing for 1-3 hours, and testing for ≤0.5% p-ethylphenol to ensure it is qualified; adding a non-water-soluble solvent for extraction, stirring for 0.5-2 hours, letting stand for 0.5-1 hours to separate the layers, heating the water layer to remove a small amount of solvent and then sending it to the wastewater treatment workshop for treatment, washing the oil layer with water once, separating the layers, and obtaining an oil layer that is a solution of 2,4,6-trimethylphenol.

[0015] In some embodiments, the second catalyst is an acidic catalyst or a basic catalyst, wherein the acidic catalyst includes at least one of oxalic acid, formic acid, phosphoric acid or hydrochloric acid; and the basic catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate or ammonia water. The amount of the second catalyst used is 0.01–0.5 wt% of the total amount of phenolic raw materials. The amount of the aldehyde is 0 to 0.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-dimethylphenol, and 3,4-dimethylphenol.

[0016] In some embodiments, the non-water-soluble solvent includes at least one of aromatic hydrocarbons, chloroalkanes, ethers, ketones, or esters; the amount of the non-water-soluble solvent used is 0.5 to 2 times the total weight of the phenolic raw materials. The amount of water used when washing the oil layer is 0.01 to 0.1 times the weight of the non-water-soluble solvent.

[0017] In some embodiments, the method further includes step (5), adding the obtained 2,4,6-trimethylphenol solution to a distillation vessel with 5 to 30 trays, heating the vessel to atmospheric pressure and then reducing the pressure to remove the solvent, transferring the material in the distillation vessel to a high-efficiency distillation vessel with 100 to 250 trays, and distilling to obtain 99% 2,4,6-trimethylphenol or crude 2,4,6-trimethylphenol, and feeding the residue into a polymerization reactor for the next batch of phenolic resin synthesis reaction; The pressure of the vacuum distillation is -0.03 to -0.07 MPa, and the reflux ratio is (1 to 3):1. The pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 25):1. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0019] The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to embodiments of the present invention includes the following steps: (1) Add a portion of phenolic material containing 2,4,6-trimethylphenol, a portion of aldehydes, and a first catalyst to a polymerization reactor, start stirring, and heat to 60-105℃ for 1-6 hours. Add the remaining phenolic material containing 2,4,6-trimethylphenol and the remaining aldehydes dropwise over 1-4 hours. After adding, keep warm for 1-6 hours and take a sample for analysis. The p-ethylphenol content is ≤5% and qualified. The phenolic material containing 2,4,6-trimethylphenol includes: 10-60 wt% m-p-ethylphenol, 10-90 wt% 2,4,6-trimethylphenol, 10-30 wt% 3,5-xylenol, 0-10 wt% 2,4 / 2,5-methylethylphenol, and 0-10 wt% 3,4-xylenol. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the time is 2-5 hours. The final pressure is controlled at -0.075--0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes. (3) Gradually increase the vacuum to -0.09 to -0.1 MPa within 1 to 2 hours, while further heating and dehydrating. When the temperature of the material in the kettle reaches 80 to 230°C and no liquid distills out, keep it warm for 0.5 to 1 hour, stop dehydration, release the vacuum with nitrogen, and cool the material while it is hot under nitrogen protection to obtain phenolic resin.

[0020] The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol in this invention utilizes the characteristic that 2,4,6-trimethylphenol reacts very little with aldehydes. It completely reacts m-ethylphenol, p-ethylphenol, 3,5-xylenol, and 3,4-xylenol, all containing 2,4,6-trimethylphenol, with formaldehyde. This method uses some inexpensive phenolic materials containing 2,4,6-trimethylphenol to replace phenol in the production of phenolic resin, while simultaneously producing 99% 2,4,6-trimethylphenol, resulting in good economic benefits and expanding the range of phenolic resins containing 2,4,6-trimethylphenol. The application scope and market size of phenolic materials containing 2,4,6-trimethylphenol; the method of this invention, which uses m-p-ethylphenol containing 2,4,6-trimethylphenol to replace phenol in the production of phenolic resin, can effectively solve the market problem of m-p-ethylphenol containing 2,4,6-trimethylphenol generated from the refining of 100,000 to 200,000 tons of crude phenol produced in newly built coal gasification, coal pyrolysis, and coal liquefaction industries, and reduce the production cost of phenolic resin, thus contributing to the healthy and orderly development of the coal gasification, coal liquefaction, and coal pyrolysis industries.

[0021] In some embodiments, preferably, in step (1), a first phenolic component is added to the polymerization reactor. The first phenolic component includes at least one of m-cresol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3,5-xylenol, phenol, or 3-ethyl-5-cresol. The amount of the first phenolic component is 0.1% to 200% of the mass of the phenolic material containing 2,4,6-trimethylphenol, for example, 0.1%, 5%, 10%, 20%, 40%, 60%, 80%, 100%, 120%, 140%, 160%, 180%, or 200%. More preferably, the first phenolic component is coal-derived phenol. The selected first phenolic component has a functionality of 3 when reacting with aldehydes.

[0022] In this embodiment of the invention, when the content of 2,4,6-trimethylphenol in the phenolic raw material containing 2,4,6-trimethylphenol is high (≥50%), the other phenols are mainly 3,5-xylenol and some m-,p-ethylphenol. At this time, the phenolic resin obtained by direct reaction with formaldehyde is relatively rigid and the reaction rate is too fast, which is not conducive to the subsequent processing of phenolic resin. Therefore, adding phenol can control the reaction rate and adjust the structure of phenolic resin. When the content of 2,4,6-trimethylphenol in the phenolic raw material containing 2,4,6-trimethylphenol is low (≤50%, especially ≤30%), the other phenols are mainly m-,p-ethylphenol and 2,3-xylenol. The molecular chain structure can be adjusted by adding some m-cresol, m-ethylphenol, m-isopropylphenol and phenol to ensure the performance of phenolic resin. Simultaneously, by adding highly reactive 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol, and phenol as the first phenolic component, a prepolymer with an average functionality of not less than 2 is first reacted with a portion of formaldehyde. Then, the remaining formaldehyde and phenolic raw materials containing 2,4,6-trimethylphenol are added dropwise. This prepolymer can then react with 2,4-methylethylphenol from phenolic raw materials containing 2,4,6-trimethylphenol, yielding another prepolymer with a functionality of not less than 2. This prepolymer then continues to react with phenolic raw materials containing 2,4,6-trimethylphenol, specifically with intermediate-term ethyl phenol. The phenolic resin produced by the reaction of methylphenol and other substances has better performance than ordinary phenolic resin (phenol is the raw material); the small amount of 6-hydroxymethyl-2,4-methylethylphenol produced by the reaction of 2,4-methylethylphenol with formaldehyde can also easily react with 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol and phenol to generate intermediates with a functionality of not less than 2. The intermediates can then be further reacted with 2,5-xylenol, 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol, phenol and p-ethylphenol to obtain phenolic resins with performance that meet the customer's requirements.

[0023] In some embodiments, preferably, in step (1), the phenolic material containing 2,4,6-trimethylphenol is obtained by distillation of crude phenol extracted from coal coking, crude phenol extracted from medium- and low-temperature coal gasification, or crude phenol extracted from phenol-containing coal tar by coal pyrolysis. More preferably, the phenolic material containing 2,4,6-trimethylphenol is obtained by distillation of crude phenol extracted from medium- and low-temperature coal gasification or crude phenol extracted from phenol-containing coal tar by coal pyrolysis.

[0024] In some embodiments, preferably, in step (1), the aldehydes include at least one of paraformaldehyde, formaldehyde, or acetaldehyde; The amount of aldehyde used is 0.8 to 2.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol. More preferably, the aldehyde is formaldehyde, and the amount of aldehyde used is 1.0 to 2.0 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol.

[0025] In some embodiments, preferably, in step (1), a portion of the phenolic material containing 2,4,6-trimethylphenol is 0 to 100 wt% of the total phenolic material, and a portion of the aldehyde is 0 to 100 wt% of the total aldehyde.

[0026] In some embodiments, preferably, in step (1), the first catalyst is an acidic catalyst, which includes at least one of oxalic acid, formic acid, phosphoric acid, hydrochloric acid, aminosulfonic acid, or benzenesulfonic acid; the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials. More preferably, the acidic catalyst is a mixture of hydrochloric acid, oxalic acid, and phosphoric acid.

[0027] In some embodiments, preferably, in step (1), the first catalyst is an alkaline catalyst, which includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water; the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials. Step (2) involves adding glacial acetic acid or formic acid to neutralize the pH to 6-7 after the reaction is complete, gradually increasing the vacuum to -0.07 to -0.1 MPa over 0.5-1 hours to begin dehydration. When the dehydration rate slows down or the temperature drops to around 70-75°C, heating is used to continue dehydration, controlling the final liquid temperature at 70-90°C until the water level reaches the required value. A sample is then taken for analysis to determine the moisture content of the material to be ≤5%. Step (3) involves adding ethylene glycol to the polymerization reactor, stirring it evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, and adding ethanol to adjust the viscosity to 10-30 Pa·s according to the requirements of different products. After the viscosity reaches the required level, the temperature is lowered to 50°C and the material is discharged. The amount of ethylene glycol used is 1-10% of the mass of the phenolic raw materials.

[0028] In some embodiments, preferably, the process further includes step (4): adding a second catalyst and aldehydes to the distilled material, heating to 80-105°C and refluxing for 1-3 hours, and testing for ≤0.5% p-ethylphenol to ensure it is qualified; adding a non-water-soluble solvent for extraction, stirring for 0.5-2 hours, allowing to stand for 0.5-1 hours to separate the layers, heating the water layer to remove a small amount of solvent and then sending it to the wastewater treatment workshop for treatment, washing the oil layer once with water, separating the layers, and obtaining an oil layer that is a solution of 2,4,6-trimethylphenol.

[0029] The method of this invention addresses the potential presence of unreacted p-ethylphenol and formaldehyde in the distilled material during polycondensation. To ensure the quality of the 2,4,6-trimethylphenol product, an acid catalyst is added to the distilled water for prepolymerization of the phenolic materials. The unreacted free p-ethylphenol further reacts with the aldehyde to generate a linear prepolymer, thus removing excess formaldehyde and p-ethylphenol. This facilitates the extraction of 99% high-quality 2,4,6-trimethylphenol and also benefits the treatment of phenol-containing wastewater. The linear prepolymer is returned to the polymerization system, increasing resin production and reducing solid waste.

[0030] In some embodiments, preferably, the second catalyst is an acidic catalyst or a basic catalyst, wherein the acidic catalyst includes at least one of oxalic acid, formic acid, phosphoric acid or hydrochloric acid; and the basic catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate or ammonia water. The amount of the second catalyst used is 0.01–0.5 wt% of the total amount of phenolic raw materials. The amount of the aldehyde is 0 to 0.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol. More preferably, the second catalyst is hydrochloric acid.

[0031] In some embodiments, preferably, the non-water-soluble solvent includes at least one of aromatic hydrocarbons, chloroalkanes, ethers, ketones, or esters; the amount of the non-water-soluble solvent used is 0.5 to 2 times the total weight of the phenolic raw materials. The amount of water used during the washing of the oil layer is 0.01 to 0.1 times the weight of the non-water-soluble solvent. More preferably, the non-water-soluble solvent is at least one of toluene or methyl isobutyl ether.

[0032] In some embodiments, preferably, the method further includes step (5), adding the obtained 2,4,6-trimethylphenol solution to a distillation vessel with 5 to 30 trays, heating the vessel to atmospheric pressure and then reducing the pressure to remove the solvent, transferring the material in the distillation vessel to a high-efficiency distillation vessel with 100 to 250 trays, and distilling to obtain 99% 2,4,6-trimethylphenol or crude 2,4,6-trimethylphenol, and feeding the residue into a polymerization reactor for the next batch of phenolic resin synthesis reaction; The pressure of the vacuum distillation is -0.03 to -0.07 MPa, and the reflux ratio is (1 to 3):1. The pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 25):1.

[0033] In the method of this invention, the main component of the reactor residue is a prepolymer. A linear prepolymer generated by the secondary polymerization of formaldehyde with meta-ortho-phenol / meta-para-phenol / para-phenol distilled from the synthesis of phenolic resin is used as a base. This prepolymer is then added to the polymerization reactor for the next batch of phenolic resin synthesis reaction. By adding phenolic materials containing 2,4,6-trimethylphenol dropwise to react with formaldehyde, a small amount of 6-hydroxymethyl-2,4-methylethylphenol in the prepolymer is rapidly polymerized with meta-ethylphenol, 3,5-xylenol in the phenolic materials containing 2,4,6-trimethylphenol, and meta-cresol, meta-ethylphenol, and phenol in the first phenolic component to generate an intermediate with a functionality of 2. This intermediate can continue to polymerize to produce phenolic resin. The proportion of linear segments in the phenolic resin product increases, giving the phenolic resin better processing performance.

[0034] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0035] Example 1 (1) In the polymerization reactor, start stirring and add 264.8 parts of the previous batch of prepolymer (residue after oil distillation treatment) (all figures in the examples refer to parts by weight), 45 parts of oxalic acid (dissolved in 60 parts of water, the oxalic acid being 3wt% of the total phenolic raw materials). After feeding, measure the pH of the reaction solution with pH paper to be 2.7. Adjust the reflux and venting devices, open the steam valve to raise the temperature, the steam pressure should not exceed 0.3 MPa, the reactor temperature is 95℃, and gradually add 676 parts of 37% formaldehyde (the total amount of formaldehyde used is m-ethylphenol, 3,5-xylenol, 3,4-xylenol, 2, Add 1500 parts of m-p-ethylphenol containing 2,4,6-trimethylphenol (1.6 times the total molar mass of 5-methylethylphenol), including 363 parts of p-ethylphenol, 432 parts of m-ethylphenol, 124.5 parts of 3,5-xylenol, 67.5 parts of 3,4-xylenol, 466.5 parts of 2,4,6-trimethylphenol, 33 parts of 2,4-methylethylphenol, and 13.5 parts of 2,5-methylethylphenol), over a period of 3 hours. After the addition is complete, add 15 parts of 85% phosphoric acid (1 wt% of the total phenolic raw materials). Heat slowly to avoid excessively rapid heating, which could cause the reaction solution to overflow and affect the resin quality.

[0036] The temperature was raised to 98℃, and the reaction was started by maintaining the temperature at 98-102℃. After 3 hours of maintenance, samples were taken for analysis. Liquid chromatography analysis showed that the levels of meta-phenol / meta-p-phenol / meta-ortho-phenol (meta-ethylphenol, 3,5-xylenol, 3,4-xylenol, 2,5-methylethylphenol) were 0.31%, p-ethylphenol was 4.65%, and free phenol was 17.99%, which met the requirements. The steam valve was then opened to heat and dehydrate the product. The temperature was gradually raised to 130℃ to remove most of the water, which took about 2 hours. The temperature was then slightly lowered to 75℃.

[0037] (2) Adjust the vacuum device and start vacuum dehydration. Control the dehydration temperature at 80-85℃, the time at 2 hours, and the final pressure at -0.08Mpa. At the same time, observe the water level in the receiver. Specifically, the water level should be constant within 20 minutes.

[0038] (3) Gradually increase the vacuum to -0.098 MPa for 1 hour, further increase the temperature to dehydrate, and when the temperature of the material in the kettle reaches 210℃ and no liquid distills out, dehydrate for 3 hours, continue to keep warm for 0.5 hours, stop dehydration, use nitrogen to release the vacuum, and under nitrogen protection, put the hot material into a stainless steel pan to cool, then crush and bag it to obtain 1220.8 parts of phenolic resin (softening point 105℃, free phenol 0.1%, residual carbon 80.3%), with a color of off-white to light yellow, and distillate is obtained at the same time.

[0039] (4) Add the distillate to the extraction vessel, add 5 parts of 36% hydrochloric acid (the amount of hydrochloric acid is 0.33 wt% of the total amount of phenolic raw materials), and 200 parts of 37% formaldehyde (the amount of formaldehyde is 0.47 times the total molar amount of the first phenolic component, m-p-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol). Heat to 100-105℃ and react for 2 hours. Take a sample for analysis and the p-ethylphenol content is 0.03%, which is qualified. Then add 2000 parts of methyl isobutyl ketone (the amount of methyl isobutyl ketone is 0.33 wt% of the total amount of phenolic raw materials). After stirring for 1 hour (1.33 times the total weight), the mixture separated into layers. The oil layer was washed once with 100 parts of water and allowed to stand to separate. The upper layer was a methyl isobutyl ketone solution of 2,4,6-trimethylphenol / 2,4-methylethylphenol, consisting of 2713.4 parts (containing 0.3 parts of p-ethylphenol, 460.3 parts of 2,4,6-trimethylphenol, 13.5 parts of 2,4-methylethylphenol, and 261.3 parts of prepolymer). The water layer was heated and refluxed to obtain 5.3 parts of methyl isobutyl ketone for reuse. The remaining 855.6 parts of the water layer were cooled to 60°C and sent to the waste treatment workshop for further processing.

[0040] (5) 2713.4 parts of the methyl isobutyl ketone solution of 2,4,6-tricresol / 2,4-methylethylphenol were added to a distillation vessel with 10 trays. The temperature was raised first to atmospheric pressure and then to vacuum distillation (-0.05 MPa, reflux ratio 2:1) to remove 1961.5 parts of methyl isobutyl ketone. Then the remaining material in the vessel was transferred to a high-efficiency distillation column (250 theoretical trays) and vacuum distilled (-0.085 MPa, reflux ratio 25:1) to obtain 334 parts of 99.5% 2,4,6-tricresol and 127.3 parts of 2,4,6-tricresol / 2,4-methylethylphenol (118.1 parts of 2,4,6-tricresol and 9.2 parts of 2,4-methylethylphenol). 265.6 parts of the residue in the vessel (including 261.3 parts of prepolymer) were returned to the first step polymerization reactor to be used with other phenolic substances for the next batch of phenolic resin synthesis.

[0041] Since 2,4,6-trimethylphenol does not react with isobutylene, the reaction of 2,4,6-trimethylphenol / 2,4-methylethylphenol with isobutylene and subsequent distillation yields 99% 2,4,6-trimethylphenol, with the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol as a byproduct.

[0042] Example 2 (1) In the reactor, start stirring and add 35 parts of the previous batch of prepolymer, 500 parts of molten 99.2% coal-based phenol, 500 parts of crude 2,4,6-trimethylphenol (containing 43 parts of p-ethylphenol, 51 parts of m-ethylphenol, 91.5 parts of 3,5-xylenol, 22.5 parts of 3,4-xylenol, 255.5 parts of 2,4,6-trimethylphenol, 26 parts of 2,4-methylethylphenol, and 10.5 parts of 2,5-methylethylphenol), and 500 parts of 37% formaldehyde (the total amount of formaldehyde is the total amount of phenol, m-ethylphenol, 3,5-xylenol, 3,4-xylenol, and 2,5-methylethylphenol). Add 1.5 times the mass of phenolic resin and 30 parts of 85% phosphoric acid (2wt% of the total phenolic raw materials). After feeding, measure the pH of the reaction solution with pH paper to be 1.8. Adjust the reflux and venting devices, open the steam valve to raise the temperature, and the steam pressure should not exceed 0.3 MPa. React at 90℃ for 2 hours. Add 15 parts of 85% phosphoric acid (1wt% of the total phenolic raw materials), and gradually add 500 parts of 37% formaldehyde and 500 parts of the remaining crude 2,4,6-trimethylphenol over 3 hours. After adding, raise the temperature slowly to avoid excessive heating, which could cause the reaction solution to overflow and affect the resin quality.

[0043] The temperature was raised to 98℃, and the reaction was started by maintaining the temperature at 98-102℃, then stabilized at 100℃. After 3 hours of holding, samples were taken for analysis. Liquid chromatography analysis showed that the levels of meta-phenol (m-ethylphenol, 3,5-xylenol, 3,4-xylenol, 2,5-methylethylphenol) were 0.083%, p-ethylphenol was 1.18%, and free phenol was 22.43%, which met the requirements. The steam valve was then opened to heat and dehydrate the product. The temperature was gradually raised to 125℃ to remove most of the water over approximately 2 hours, and then the temperature was slightly lowered to 75℃.

[0044] (2) Adjust the vacuum device and start vacuum dehydration. Control the dehydration temperature at 80-85℃, the time at 2 hours, and the final pressure at -0.08Mpa. At the same time, observe the water level in the receiver. Specifically, the water level should be constant within 20 minutes.

[0045] (3) Gradually increase the vacuum to -0.095 MPa for 1.5 hours, further increase the temperature to dehydrate, and when the temperature of the material in the kettle reaches 200℃ and no liquid distills out, the dehydration time is 2.5 hours. Continue to keep the temperature for 1 hour, stop dehydration, use nitrogen to release the vacuum, and under nitrogen protection, put the hot material into a stainless steel pan to cool, then crush and bag it to obtain 1172.8 parts of phenolic resin (softening point 110℃, free phenol 0.6%, residual carbon 78.2%), with a color of off-white to light yellow, and distillate is obtained at the same time.

[0046] (4) Add the distillate to the extraction vessel, add 2 parts of 36% hydrochloric acid (the amount of hydrochloric acid is 0.13 wt% of the total amount of phenolic raw materials), and 20 parts of 37% formaldehyde (the amount of formaldehyde is 0.03 times the total molar amount of the first phenolic component, m-p-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol). Heat to 100°C and react for 1.5 hours. Then add 1500 parts of methyl isobutyl ketone (the amount of methyl isobutyl ketone is 1 / 3 wt% of the total weight of phenolic raw materials). After stirring for 1 hour (0.0 times), the mixture separated into layers. The oil layer was washed once with 100 parts of water and allowed to stand to separate. The upper layer was a methyl isobutyl ketone solution of 2,4-methylethylphenol / 2,4,6-trimethylphenol, containing 499.4 parts of 2,4,6-trimethylphenol, 28.8 parts of 2,4-methylethylphenol, 0.3 parts of other phenols, and 31.1 parts of prepolymer. The water layer was heated and refluxed to obtain 3.8 parts of toluene for reuse. The remaining 860 parts of the water layer were cooled to 60°C and sent to the waste treatment workshop for further processing.

[0047] (5) 2041.6 parts of phenol / p-cresol methyl isobutyl ketone solution were added to a distillation vessel with 30 trays. The temperature was raised first to atmospheric pressure and then to vacuum distillation (-0.05 MPa, reflux ratio 2:1) to remove 1462.7 parts of methyl isobutyl ketone. Then the remaining material in the vessel was transferred to a high-efficiency distillation column (250 theoretical trays) and vacuum distilled (-0.085 MPa, reflux ratio 25:1) to obtain 439.9 parts of 99.1% 2,4,6-trimethylphenol and 71.3 parts of 2,4,6-trimethylphenol / 2,4-methylethylphenol (50.9 parts of 2,4,6-trimethylphenol and 20.4 parts of 2,4-methylethylphenol). 34.9 parts of the residue in the vessel (including 31.1 parts of prepolymer) were returned to the first step polymerization reactor to be used with other phenolic substances for the next batch of phenolic resin synthesis.

[0048] Since 2,4,6-trimethylphenol does not react with isobutylene, 2,4,6-trimethylphenol / 2,4-methylethylphenol can be reacted with isobutylene separately, and 99% 2,4,6-trimethylphenol can be obtained by distillation, with the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol as a byproduct.

[0049] Example 3 (1) In the polymerization reactor, start stirring and add 81.5 parts of the previous batch of prepolymer, 600 parts of phenol, 200 parts of m-cresol, 200 parts of m-ethylphenol, 1000 parts of 37% formaldehyde (the total amount of formaldehyde is 1.81 times the total molar mass of phenol, m-cresol, m-ethylphenol, 3,5-xylenol, 3,4-xylenol, and 2,5-methylethylphenol), and 150 parts of 31% liquid alkali (the total amount of alkali is 3.5w% of the total amount of phenolic raw materials). After feeding, adjust the reflux and venting devices, open the steam valve to raise the temperature, start stirring, and heat to 70-70°C. The reaction was carried out at 5℃ for 2 hours; the temperature was then raised to 80-85℃, and 76 parts of 31% liquid alkali were added. 1000 parts of crude 2,4,6-trimethylphenol (containing 86 parts of p-ethylphenol, 102 parts of m-ethylphenol, 183 parts of 3,5-xylenol, 45 parts of 3,4-xylenol, 511 parts of 2,4,6-trimethylphenol, 52 parts of 2,4-methylethylphenol, and 21 parts of 2,5-methylethylphenol) were added dropwise, along with 870 parts of 37% formaldehyde. The addition time was 3.0 hours. The mixture was kept at this temperature for 6 hours before sampling and analysis. Liquid chromatography analysis showed that p-ethylphenol was 1.02% and free phenol was 14.7%, which met the requirements.

[0050] (2) After the reaction is complete, add 105 parts of acetic acid to neutralize to pH 6.5. Gradually open the vacuum to -0.095 MPa over 1 hour to start dehydration. During dehydration, return the water in the upper part of the separator to the reactor through the water separator on the reactor. Observe the dehydration speed as it slows down or until the temperature drops to 70°C. Then heat and continue dehydration for about 1.5 hours. At this time, change to directly put the distilled water into the receiving tank. After 2 hours, the liquid temperature in the reactor is 80°C. Take a sample for analysis and the moisture content of the material is 2.8%, which is qualified. (3) Add 60 parts of ethylene glycol, stir evenly, take a sample to analyze the moisture and viscosity. Stop vacuuming when the moisture content is 2.6%, and add 30 parts of ethanol to adjust the viscosity to 15 Pa·s. Cool down to 50℃ and discharge to obtain 2206.8 parts of material. Test the free phenol content of 4.8%, free aldehyde content of 0.91%, solid content of 80.9%, residual carbon content of 50.8%, moisture content of 2.5%, and viscosity of 16 Pa·s.

[0051] (4) Add 5 parts of 36% hydrochloric acid (the amount of hydrochloric acid is 0.25 wt% of the total amount of phenolic raw materials) and 37 parts of 37% formaldehyde (the amount of formaldehyde is 0.036 times the total molar amount of the first phenolic component, m- and p-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol) to the distilled water, heat to 102℃ and react for 1.5 hours. Take a sample for analysis, and the p-ethylphenol content is 0.04%, which is qualified. After 0.5 hours, cool the material to 60℃ and add 1500 parts of formaldehyde. Benzene (toluene content is 0.75 times the total weight of phenolic raw materials) was stirred for 1 hour, allowed to stand for 0.5 hours, and separated into layers. The lower water layer (1526.8 parts) was heated to recover 2.3 parts of toluene and then sent to the wastewater treatment workshop. The upper oil layer was washed once with 50 parts of water. The resulting oil layer was a solution of 2066.9 parts of unreacted phenolic substances (0.4 parts of p-ethylphenol, 25.8 parts of 2,4-methylethylphenol, 479 parts of 2,4,6-trimethylphenol, and 78.2 parts of prepolymer).

[0052] (5) 2066.9 parts of the water-washed layered oil were added to a distillation vessel with 20 trays. The temperature was raised first to atmospheric pressure and then reduced to vacuum (-0.05 MPa, reflux ratio of 2:1) to distill off 1468.1 parts of solvent. The material in the distillation vessel was transferred to a high-efficiency distillation vessel with 250 trays and distilled (-0.085 MPa, reflux ratio of 30:1) to obtain 226.8 parts of 99.1% 2,4,6-trimethylphenol, 253.7 parts of 2,4,6-trimethylphenol / 2,4-methylethylphenol (242.8 parts of 2,4,6-trimethylphenol and 10.9 parts of 2,4-methylethylphenol), and 11.2 parts of 99.3% 2,4-methylethylphenol. 81.3 parts of residue in the distillation vessel (3.1 parts of phenol and 78.2 parts of prepolymer) were left. The prepolymer was returned to the polymerization reactor for the next batch of phenolic resin synthesis.

[0053] Example 4 (1) In the polymerization reactor, start stirring and add 67.5 parts of the previous batch of prepolymer, 500 parts of molten coal-derived 99.2% phenol, 500 parts of crude 2,4,6-trimethylphenol (containing 43 parts of p-ethylphenol, 51 parts of m-ethylphenol, 91.5 parts of 3,5-dimethylphenol, 22.5 parts of 3,4-dimethylphenol, 255.5 parts of 2,4,6-trimethylphenol, 26 parts of 2,4-methylethylphenol, and 10.5 parts of 2,5-methylethylphenol), 242 parts of 31% liquid alkali (5 wt% of the total amount of phenolic raw materials), and 630 parts of 37% formaldehyde (the total amount of formaldehyde used is phenol, m-ethylphenol, 3,5-dimethylphenol, 3,4-dimethylphenol, and 2,5-methylethylphenol). (1.7 times the total molar mass of methylphenol). After feeding, adjust the reflux and venting devices, open the steam valve to raise the temperature, start the stirrer, and heat to 40-50℃. At around 50-60℃, open the jacket cooling water to remove the heat of reaction, slowly raise the temperature to 80-85℃, and keep the reaction at this temperature for 2 hours. Add 500 parts of 37% formaldehyde and 500 parts of crude 2,4,6-trimethylphenol dropwise over 2.5 hours. After the addition is complete, keep the temperature for 5 hours and take samples for analysis. Liquid chromatography analysis shows that the levels of meta-phenol (0.12%, including meta-ethylphenol, 3,5-xylenol, 3,4-xylenol, and 2,5-methylethylphenol), p-ethylphenol (2.35%), and free phenol (21.42%) are within acceptable limits.

[0054] (2) After the reaction is complete, add 86.5 parts of formic acid to neutralize to pH 6.5. Gradually open the vacuum to -0.09MPa over 1 hour to start dehydration. During dehydration, return the water in the upper part of the separator to the reactor through the separator on the reactor. Observe the dehydration speed as it slows down or until the temperature drops to 70℃. Then heat and continue dehydration for about 2 hours. At this time, change to directly put the distilled water into the receiving tank. After 2 hours, the liquid temperature in the reactor is 75℃. Take a sample for analysis and the moisture content of the material is 2.7%, which is qualified. (3) Add 45 parts of ethylene glycol, stir evenly, take samples to analyze moisture and viscosity. Stop vacuuming when the moisture content is 2.7%, and add 15 parts of ethanol to adjust the viscosity to 17 Pa.s. Cool down to 50℃ and discharge to obtain 1449.5 parts of material. Test the free phenol content of 4.5%, free aldehyde content of 0.79%, solid content of 82.3%, residual carbon content of 51.2%, moisture content of 2.7%, and viscosity to 17 Pa.s.

[0055] (4) Add 4 parts of hydrochloric acid (the amount of hydrochloric acid is 0.27 wt% of the total amount of phenolic raw materials) and 80 parts of 37% formaldehyde (the amount of formaldehyde is 0.12 times the total molar amount of the first phenolic component, m- and p-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol). Heat the mixture to 102℃ and react for 1 hour. Take a sample for analysis. The p-ethylphenol content is 0.02%, which is qualified, and the free aldehyde content is 0.19%. After 0.5 hours, cool the material to 60℃ and add 1500 ml of formaldehyde. Mix 1 part toluene (the amount of toluene is 1.0 times the total weight of the phenolic raw materials), stir for 1 hour, let stand for 0.5 hours, separate into layers, heat the lower water layer to recover 6.3 parts of toluene and send it to the wastewater treatment plant (1065.9 parts), wash the upper oil layer with 50 parts of water once, and the oil layer obtained by separation is 2038.2 parts of unreacted phenolic substance solution (34.5 parts of 2,4-methylethylphenol, 452.3 parts of 2,4,6-trimethylphenol, 0.6 parts of other phenols, and 64.3 parts of prepolymer).

[0056] (4) 2038.2 parts of the water-washed layered oil were added to a distillation vessel with 20 trays. The temperature was raised first to atmospheric pressure and then reduced to vacuum (-0.05 MPa, reflux ratio of 2:1) to distill off 1469 parts of solvent. The material in the distillation vessel was transferred to a high-efficiency distillation vessel with 250 trays and distilled (-0.085 MPa, reflux ratio of 30:1) to obtain 374.4 parts of 99.3% 2,4,6-trimethylphenol and 14.7 parts of 99.1% 2,4-methylethylphenol. 67.6 parts of residue in the distillation vessel (3.3 parts of phenol and 64.3 parts of prepolymer) were left in the reboiler. The prepolymer was returned to the polymerization reactor for the next batch of phenolic resin synthesis.

[0057] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol, characterized in that, Includes the following steps: (1) Add a portion of phenolic material containing 2,4,6-trimethylphenol, a portion of aldehydes, and a first catalyst to a polymerization reactor, start stirring, and heat to 60-105℃ for 1-6 hours. Add the remaining phenolic material containing 2,4,6-trimethylphenol and the remaining aldehydes dropwise over 1-4 hours. After adding, keep warm for 1-6 hours and take a sample for analysis. The p-ethylphenol content is ≤5% and qualified. The phenolic material containing 2,4,6-trimethylphenol includes: 10-60 wt% m-p-ethylphenol, 10-90 wt% 2,4,6-trimethylphenol, 10-30 wt% 3,5-xylenol, 0-10 wt% 2,4 / 2,5-methylethylphenol, and 0-10 wt% 3,4-xylenol. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the time is 2-5 hours. The final pressure is controlled at -0.075--0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes. (3) Gradually increase the vacuum to -0.09 to -0.1 MPa within 1 to 2 hours, while further heating and dehydrating. When the temperature of the material in the kettle reaches 80 to 230°C and no liquid distills out, keep it warm for 0.5 to 1 hour, stop dehydration, release the vacuum with nitrogen, and cool the material while it is hot under nitrogen protection to obtain phenolic resin.

2. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 1, characterized in that, In step (1), a first phenolic component is added to the polymerization reactor. The first phenolic component includes at least one of m-cresol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3,5-xylenol, phenol, or 3-ethyl-5-cresol. The amount of the first phenolic component is 0.1% to 200% of the mass of the phenolic material containing 2,4,6-trimethylphenol. And / or, in step (1), the phenolic material containing 2,4,6-trimethylphenol is obtained by distillation of crude phenol extracted from coal coking crude phenol, medium-low temperature coal gasification crude phenol, or phenolic coal tar extracted by coal pyrolysis.

3. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 2, characterized in that, In step (1), the aldehydes include at least one of paraformaldehyde, formaldehyde, or acetaldehyde; The amount of aldehydes used is 0.8 to 2.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-dimethylphenol, and 3,4-dimethylphenol.

4. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 1, characterized in that, In step (1), a portion of the phenolic material containing 2,4,6-trimethylphenol is 0 to 100 wt% of the total phenolic material, and a portion of the aldehydes is 0 to 100 wt% of the total aldehydes.

5. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 1, characterized in that, In step (1), the first catalyst is an acidic catalyst, which includes at least one of oxalic acid, formic acid, phosphoric acid, hydrochloric acid, aminosulfonic acid or benzenesulfonic acid, and the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials.

6. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 1, characterized in that, In step (1), the first catalyst is an alkaline catalyst, which includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water; the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials. Step (2) involves adding glacial acetic acid or formic acid to neutralize the pH to 6-7 after the reaction is complete, gradually increasing the vacuum to -0.07 to -0.1 MPa over 0.5-1 hours to begin dehydration. When the dehydration rate slows down or the temperature drops to around 70-75°C, heating is used to continue dehydration, controlling the final liquid temperature at 70-90°C until the water level reaches the required value. A sample is then taken for analysis to determine the moisture content of the material to be ≤5%. Step (3) involves adding ethylene glycol to the polymerization reactor, stirring it evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, and adding ethanol to adjust the viscosity to 10-30 Pa·s according to the requirements of different products. After the viscosity reaches the required level, the temperature is lowered to 50°C and the material is discharged. The amount of ethylene glycol used is 1-10% of the mass of the phenolic raw materials.

7. The method for synthesizing phenolic resin from a mixture of 2,4,6-trimethylphenols according to claim 5 or 6, characterized in that, The process also includes step (4): adding a second catalyst and aldehydes to the distilled material, heating to 80-105℃ and refluxing for 1-3 hours, and testing for ≤0.5% of p-ethylphenol to ensure it is qualified; adding a non-water-soluble solvent for extraction, stirring for 0.5-2 hours, letting it stand for 0.5-1 hours to separate the layers, heating the water layer to remove a small amount of solvent and then sending it to the wastewater treatment workshop for treatment, washing the oil layer with water once, separating the layers, and obtaining an oil layer that is a solution of 2,4,6-trimethylphenol.

8. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 7, characterized in that, The second catalyst is an acidic catalyst or a basic catalyst. The acidic catalyst includes at least one of oxalic acid, formic acid, phosphoric acid, or hydrochloric acid. The basic catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water. The amount of the second catalyst used is 0.01–0.5 wt% of the total amount of phenolic raw materials. The amount of the aldehyde is 0 to 0.5 times the total molar amount of the first phenolic component, m-ethylphenol, 2,5-methylethylphenol, 3,5-dimethylphenol, and 3,4-dimethylphenol.

9. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 7, characterized in that, The non-water-soluble solvent includes at least one of aromatic hydrocarbons, chlorinated alkanes, ethers, ketones, or esters; the amount of the non-water-soluble solvent used is 0.5 to 2 times the total weight of the phenolic raw materials. The amount of water used when washing the oil layer is 0.01 to 0.1 times the weight of the non-water-soluble solvent.

10. The method for synthesizing phenolic resin from mixed phenols containing 2,4,6-trimethylphenol according to claim 7, characterized in that, The process also includes step (5), in which the obtained 2,4,6-trimethylphenol solution is added to a distillation vessel with 5 to 30 trays, and the solvent is removed by distillation under normal pressure and then under reduced pressure. The material in the distillation vessel is then transferred to a high-efficiency distillation vessel with 100 to 250 trays to obtain 99% 2,4,6-trimethylphenol or crude 2,4,6-trimethylphenol. The residue in the vessel is fed into a polymerization reactor for the next batch of phenolic resin synthesis reaction. The pressure of the vacuum distillation is -0.03 to -0.07 MPa, and the reflux ratio is (1 to 3):

1. The pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 25):1.