Method for synthesizing phenolic resin from 2, 4 / 2, 5-methyl ethyl phenol

Abstract

The invention belongs to the technical field of organic synthesis and separation, and particularly relates to a method for synthesizing phenolic resin from 2, 4 / 2, 5-methyl ethyl phenol. The invention provides a method for synthesizing phenolic resin from 2, 4 / 2, 5-methyl-ethyl phenol, which comprises the following steps: adding 2, 4 / 2, 5-methyl-ethyl phenol, aldehydes and a catalyst into a reactor, carrying out an anti-thermal insulation reaction, sampling and analyzing until the content of 2, 5-methyl-ethyl phenol is less than or equal to 0.5% and is qualified, heating, decompressing and dehydrating, steaming out unreacted 2, 4-methyl-ethyl phenol and water, and dehydrating to 100-200 DEG C to obtain linear 2, 5-methyl-ethyl phenolic resin; adding a catalyst into the steamed material, heating to completely react the reacted 2, 5-methyl 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 rectifying the oil layer to obtain 99% 2, 4-methyl ethyl phenol or pesticide intermediate 4-ethyl-2-cresol.

Description

Technical Field

[0001] This invention belongs to the technical field of organic synthesis and separation, specifically relating to a method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol. Background Technology

[0002] 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.

[0003] Therefore, how to prepare phenolic resins using 2,4 / 2,5-methylethylphenol has attracted increasing attention from those skilled in the art. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of the present invention provide a method for synthesizing phenolic resins from 2,4 / 2,5-methylethylphenol.

[0006] The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to embodiments of the present invention includes the following steps:

[0007] (1) Add a portion of 2,4 / 2,5-methylethylphenol, a portion of aldehydes and the first catalyst to the polymerization reactor, start stirring, heat to 80-105℃ and react for 1-6 hours, add the remaining 2,4 / 2,5-methylethylphenol and the remaining aldehydes dropwise at 80-105℃ for 1-4 hours, keep warm for 1-6 hours after addition and take samples for analysis. The 2,5-methylethylphenol content ≤5% is qualified. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the dehydration time is 2-5 hours. The final pressure is -0.075--0.08Mpa. At the same time, observe the water level of the receiver and take the water level as 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 reactor reaches 100 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 2,5-methylethylphenol aldehyde resin.

[0008] The advantages and technical effects of the method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol in this invention are as follows: 1. The method of this invention utilizes the difference in reactivity between 2,5-methylethylphenol and 2,4-methylethylphenol with formaldehyde, using a portion of the inexpensive 2,4 / 2,5-methylethylphenol to replace phenol in the production of local 2,5-methylethylphenol phenolic resin. Simultaneously, it produces 99% 2,4-methylethylphenol (sometimes it can also produce the pesticide intermediate 4-ethyl-2-methylphenol), p-ethylphenol, etc. The prices of 4-ethyl-2-methylphenol and p-ethylphenol are significantly higher than those of 2,4 / 2,5-methylethylphenol. 5-Methylethylphenol, this invention also has good economic benefits, while expanding the application scope and market scale of 2,4 / 2,5-methylethylphenol; 2. The method of this invention, which uses 2,4 / 2,5-methylethylphenol to replace phenol in the production of 2,5-linear phenolic resin, can effectively solve the market problem of 2,4 / 2,5-methylethylphenol produced by the refining of 100,000 to 200,000 tons of crude phenol generated in newly built coal gasification, coal pyrolysis, and coal liquefaction industries. It can contribute to the healthy and orderly development of the coal gasification, coal liquefaction, and coal pyrolysis industries and reduce the cost of producing phenolic resin.

[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, a mixture of m-isopropylphenol and m-propylphenol, 3,5-xylenol, phenol, or 3-ethyl-5-cresol. And / or, in step (1), the amount of the first phenolic component is 0.1 to 200 wt% of 2,4 / 2,5-methylethylphenol.

[0010] In some embodiments, in step (1), the 2,4 / 2,5-methylethylphenol is obtained by distillation of crude phenol extracted from coal coking crude phenol, medium-low temperature coal gasification crude phenol, or crude phenol extracted from phenol-containing coal tar by coal pyrolysis. And / or, in step (1), the 2,4 / 2,5-methylethylphenol comprises 60-100 wt% 2,4 / 2,5-methylethylphenol, 0-30 wt% 3,5-dimethylphenol, 0-20 wt% m-p-ethylphenol, 0-30 wt% 3,4-dimethylphenol, 0-10 wt% 2,3,6-trimethylphenol, 0-20 wt% m-p-isopropylphenol, wherein the 2,4 / 2,5-methylethylphenol is a mixture of 4-ethyl-2-methylphenol, 2-ethyl-4-methylphenol, 5-ethyl-2-methylphenol and 2-ethyl-5-methylphenol, or a mixture of 4-ethyl-2-methylphenol and 5-ethyl-2-methylphenol, or a mixture of 2-ethyl-4-methylphenol and 2-ethyl-5-methylphenol.

[0011] In some embodiments, in step (1), the aldehyde includes at least one of paraformaldehyde, formaldehyde, or acetaldehyde, and the molar amount of the aldehyde is 1 to 2.5 times the sum of the molar amounts of phenol, m-cresol, 3,5-xylenol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3-ethyl-5-cresol, 3,4-xylenol, and 2,5-methylethylphenol; And / or, in step (1), a portion of the 2,4 / 2,5-methylethylphenol is 0 to 100 wt% of the total amount of 2,4 / 2,5-methylethylphenol, and a portion of the aldehyde is 0 to 100 wt% of the total amount of aldehyde.

[0012] In some embodiments, in step (1), the first catalyst includes at least one of oxalic acid, formic acid, phosphoric acid, hydrochloric acid, aminosulfonic acid, benzenesulfonic acid, ammonia or organic base, and 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 includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water, and 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. Observe the dehydration rate as it slows down or until the temperature drops to around 70-75°C, then continue the dehydration process by heating, controlling the final liquid temperature at 70-90°C, until the water level reaches the required value, and taking a sample for analysis to determine the moisture content of the material is ≤5%. Step (3) involves adding ethylene glycol after the dehydration treatment is qualified, stirring evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, adding ethanol to adjust the viscosity to 10-30 Pa·s, cooling to 40-50℃ and discharging to obtain liquid 2,5-methylethylphenol aldehyde resin.

[0014] In some embodiments, the method further includes step (4), adding a second catalyst to the distilled material, heating to 80-105°C and reacting for 1-3 hours, taking a sample for analysis to find that 2,5-methylethylphenol is ≤0.5%, then adding a non-water-soluble solvent, stirring for 0.5-2 hours, letting stand for 0.5-1 hours, separating the layers, heating the lower water layer to 95-105°C to remove a small amount of solvent, and then cooling the water layer after solvent removal to 40-50°C and sending it to the wastewater treatment section for treatment, and the upper oil layer being a solution of unreacted 2,4-methylethylphenol.

[0015] In some embodiments, the second catalyst is an acidic catalyst or an alkaline catalyst. The acidic catalyst includes at least one of oxalic acid, formic acid, phosphoric acid, or hydrochloric acid, and the alkaline catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water. The amount of the second catalyst is 0.01 to 0.5 wt% of the total amount of phenolic raw materials.

[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 mass of the phenolic raw material.

[0017] In some embodiments, the oil layer 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 50 to 250 trays. The distillation yields 99% 4-ethyl-2-cresol or 99% 2,4-methylethylphenol or 2,4-methylethylphenol / 2,4,6-trimethylphenol. The residue in the distillation vessel, together with the 2,4 / 2,5-methylethylphenol raw material, 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 5):1. The pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 40):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 2,4 / 2,5-methylethylphenol according to embodiments of the present invention includes the following steps: (1) Add a portion of 2,4 / 2,5-methylethylphenol, a portion of aldehydes and the first catalyst to the polymerization reactor, start stirring, heat to 80-105℃ and react for 1-6 hours, add the remaining 2,4 / 2,5-methylethylphenol and the remaining aldehydes dropwise at 80-105℃ for 1-4 hours, keep warm for 1-6 hours after addition and take samples for analysis. The 2,5-methylethylphenol content ≤5% is qualified. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the dehydration time is 2-5 hours. The final pressure is -0.075--0.08Mpa. At the same time, observe the water level of the receiver and take the water level as 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 reactor reaches 100 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 2,5-methylethylphenol aldehyde resin.

[0020] The advantages and technical effects of the method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol in this invention are as follows: 1. The method of this invention utilizes the difference in reactivity between 2,5-methylethylphenol and 2,4-methylethylphenol with formaldehyde, using a portion of the inexpensive 2,4 / 2,5-methylethylphenol to replace phenol in the production of local 2,5-methylethylphenol phenolic resin. Simultaneously, it produces 99% 2,4-methylethylphenol (sometimes it can also produce the pesticide intermediate 4-ethyl-2-methylphenol), p-ethylphenol, etc. The prices of 4-ethyl-2-methylphenol and p-ethylphenol are significantly higher than those of 2,4 / 2,5-methylethylphenol. 5-Methylethylphenol, this invention also has good economic benefits, while expanding the application scope and market scale of 2,4 / 2,5-methylethylphenol; 2. The method of this invention, which uses 2,4 / 2,5-methylethylphenol to replace phenol in the production of 2,5-linear phenolic resin, can effectively solve the market problem of 2,4 / 2,5-methylethylphenol produced by the refining of 100,000 to 200,000 tons of crude phenol generated in newly built coal gasification, coal pyrolysis, and coal liquefaction industries. It can contribute to the healthy and orderly development of the coal gasification, coal liquefaction, and coal pyrolysis industries and reduce the cost of producing phenolic resin.

[0021] In some embodiments, preferably, in step (1), a first phenolic component is added to the polymerization reactor, the first phenolic component including at least one of m-cresol, m-ethylphenol, m-isopropylphenol, m-isopropylphenol / m-propylphenol mixture, 3,5-xylenol, phenol or 3-ethyl-5-cresol; And / or, in step (1), the amount of the first phenolic component is 0.1 to 200 wt% of 2,4 / 2,5-methylethylphenol, for example, 0.1 wt%, 5 wt%, 10 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, 100 wt%, 120 wt%, 140 wt%, 160 wt%, 180 wt%, or 200 wt%. 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, highly reactive 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol, and m-isopropylphenol / m-propylphenol, phenol are added as the first phenolic component. This component first reacts with a portion of aldehydes to generate a prepolymer with an average functionality of not less than 2. Then, the remaining formaldehyde and 2,4 / 2,5-methylethylphenol are added dropwise. This prepolymer can react with 2,4-methylethylphenol to obtain another prepolymer with a functionality of not less than 2. The prepolymer then continues to react with 2,5-methylethylphenol to produce... The performance is superior to that of ordinary phenolic resin (synthesized from phenol); the small amount of 6-hydroxymethyl-2,4-methylethylphenol generated by the reaction of 2,4-methylethylphenol with formaldehyde can easily react with 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol, and phenol to generate an intermediate mixture with a functionality of not less than 2. The intermediate can then be further reacted with 2,5-methylethylphenol, 3,5-xylenol, m-cresol, m-ethylphenol, m-isopropylphenol, and phenol to obtain a phenolic resin with performance that meets the customer's requirements.

[0023] In some embodiments, preferably, in step (1), the 2,4 / 2,5-methylethylphenol is obtained by distillation of crude phenol extracted from coal coking crude phenol, medium-low temperature coal gasification crude phenol, or crude phenol extracted from phenol-containing coal tar by coal pyrolysis. And / or, in step (1), the 2,4 / 2,5-methylethylphenol comprises 60-100 wt% 2,4 / 2,5-methylethylphenol, 0-30 wt% 3,5-dimethylphenol, 0-20 wt% m-p-ethylphenol, 0-30 wt% 3,4-dimethylphenol, 0-10 wt% 2,3,6-trimethylphenol, 0-20 wt% m-p-isopropylphenol, wherein the 2,4 / 2,5-methylethylphenol is a mixture of 4-ethyl-2-methylphenol, 2-ethyl-4-methylphenol, 5-ethyl-2-methylphenol and 2-ethyl-5-methylphenol, or a mixture of 4-ethyl-2-methylphenol and 5-ethyl-2-methylphenol, or a mixture of 2-ethyl-4-methylphenol and 2-ethyl-5-methylphenol. More preferably, the 2,4 / 2,5-methylethylphenol is obtained by distillation of crude phenol extracted from coal gasification crude phenol or phenol-containing coal tar extracted by coal pyrolysis.

[0024] In some embodiments, preferably, in step (1), the aldehyde includes at least one of paraformaldehyde, formaldehyde, or acetaldehyde, and the molar amount of the aldehyde is 1 to 2.5 times the sum of the molar amounts of phenol, m-cresol, 3,5-xylenol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3-ethyl-5-cresol, 3,4-xylenol, and 2,5-methylethylphenol. More preferably, the aldehyde is formaldehyde, and the molar amount of the aldehyde is 1.4 to 2.0 times the sum of the molar amounts of phenol, m-cresol, 3,5-xylenol, 2,3-xylenol, 2,5-xylenol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3-ethyl-5-cresol, 3,4-xylenol, and 2,5-methylethylphenol.

[0025] In some embodiments, preferably, in step (1), a portion of the 2,4 / 2,5-methylethylphenol is 0-100 wt% of the total 2,4 / 2,5-methylethylphenol, and a portion of the aldehyde is 0-100 wt% of the total aldehyde. More preferably, in step (1), a portion of the 2,4 / 2,5-methylethylphenol is 30-100 wt% of the total 2,4 / 2,5-methylethylphenol.

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

[0027] In some embodiments, preferably, in step (1), the first catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate or ammonia water, and the amount of the first catalyst is 0.5 to 10 wt% of the total amount of phenolic materials; more preferably, the first catalyst includes at least one of sodium hydroxide or ammonia water. 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. Observe the dehydration rate as it slows down or until the temperature drops to around 70-75°C, then continue the dehydration process by heating, controlling the final liquid temperature at 70-90°C, until the water level reaches the required value, and taking a sample for analysis to determine the moisture content of the material is ≤5%. Step (3) involves adding ethylene glycol after the dehydration treatment is qualified, stirring evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, adding ethanol to adjust the viscosity to 10-30 Pa·s, cooling to 50°C and discharging to obtain liquid 2,5-methylethylphenol aldehyde resin.

[0028] In some embodiments, preferably, the process further includes step (4): adding a second catalyst to the distilled material, heating to 80-105°C and reacting for 1-3 hours, taking a sample for analysis to find that 2,5-methylethylphenol is ≤0.5%, then adding a non-water-soluble solvent, stirring for 0.5-2 hours, letting stand for 0.5-1 hours, separating the layers, heating the lower water layer to 95-105°C to remove a small amount of solvent, and then cooling the water layer after solvent removal to 40-50°C and sending it to the wastewater treatment section for treatment, while the upper oil layer is a solution of unreacted 2,4-methylethylphenol.

[0029] In this embodiment of the invention, the materials distilled during polymerization may contain small amounts of 2,5-methylethylphenol, formaldehyde, p-ethylphenol, and 2,4-methylethylphenol. To ensure the quality of the 2,4-methylethylphenol product, we prepolymerize the phenolic materials by adding an acid catalyst to the distilled water. This allows unreacted free 2,5-methylethylphenol to react further with the distilled formaldehyde to generate a linear prepolymer. This removes excess formaldehyde and 2,5-methylethylphenol, which is beneficial for extracting 99% high-quality 2,4-methylethylphenol and other products, and also facilitates the treatment of phenol-containing wastewater. The linear prepolymer is returned to the polymerization system, which can increase resin production and reduce 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 is 0.01 to 0.5 wt% of the total amount of the phenolic raw material. More preferably, the second catalyst includes at least one of hydrochloric acid or oxalic 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 is 0.5 to 2 times the total mass of the phenolic raw material. More preferably, the non-water-soluble solvent includes at least one of toluene or methyl isobutyl ether.

[0032] In some embodiments, preferably, the oil layer 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 50 to 250 trays, and 99% 4-ethyl-2-cresol or 99% 2,4-methylethylphenol or 2,4-methylethylphenol / 2,4,6-trimethylphenol is obtained by distillation. The residue in the vessel is fed together with the 2,4 / 2,5-methylethylphenol raw material 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 5):1; the pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 40):1; the 2,4-methylethylphenol is 4-ethyl-2-methylphenol, 2-ethyl-4-methylphenol, or a mixture thereof.

[0033] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0034] Example 1 (1) In the reactor, start stirring and add 82.4 parts of the previous batch of prepolymer, 500 parts of 2,4 / 2,5-methylethylphenol extracted from gasified phenol (containing 18.5 parts of p-ethylphenol, 21 parts of m-ethylphenol, 47.5 parts of 3,5-xylenol, 74 parts of 3,4-xylenol, 31.5 parts of 2,4-trimethylphenol, 214 parts of 2,4-methylethylphenol, and 93.5 parts of 2,5-methylethylphenol), and 300 parts of 37% formaldehyde (the total amount of formaldehyde used is m-ethylphenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol). Add 1.99 times the total molar amount of cresol and 20 parts of 36% hydrochloric acid (the amount of hydrochloric acid is 2.0 wt% of the total amount of phenolic materials). After feeding, measure the pH of the reaction solution with pH test paper to be 1.8. Adjust the reflux and venting devices, open the steam valve to raise the temperature. The steam pressure should not exceed 0.3 MPa. React at 80-85℃ for 2 hours. Add 500 parts of the remaining 2,4 / 2,5-cresyl phenol and 300 parts of the remaining 37% formaldehyde dropwise 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.

[0035] The temperature was raised to 95℃, and the reaction was started by maintaining the temperature at 95-100℃. The temperature was stabilized at 98℃, and the sample was taken for analysis after 2 hours. The liquid chromatography analysis showed that 3,4-xylenol / 2,5-methylethylphenol 1.3% and free phenol 30.88% were within acceptable limits. The temperature was then slightly lowered to 70℃.

[0036] (2) Adjust the vacuum device and start vacuum dehydration. The dehydration temperature is controlled at 80-85℃ for 2 hours and the final pressure is controlled at -0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes.

[0037] (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 200℃ 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 706.5 parts of xylenol resin (softening point 105.8℃, free phenol 0.2%, residual carbon 79.2%), which is off-white in color, and distillate is obtained at the same time.

[0038] (4) Add the distillate to the extraction vessel, and add 5 parts of hydrochloric acid (the amount of hydrochloric acid is 0.05% of the total amount of phenolic raw materials). (wt%), heated to 100℃ and reacted for 2 hours, sampled and analyzed 0.13% 3,4-xylenol / 2,5-methylethylphenol; then 1500 parts of methyl isobutyl ketone (the amount of methyl isobutyl ketone is 1.5 times the total mass of the phenolic raw materials) were added and stirred for 30 minutes until the layers separated. The oil layer was washed once with 75 parts of water, and allowed to stand to separate. The upper layer was a methyl isobutyl ketone solution of 2,4-methylethylphenol of 1985.1 parts (containing 13.5 parts of p-ethylphenol, 355.8 parts of 2,4-methylethylphenol, 51.9 parts of 2,3,6-trimethylphenol, 0.2 parts of 3,4-xylenol, 0.3 parts of 2,5-methylethylphenol, and 79.9 parts of prepolymer); the water layer was heated and refluxed to obtain 3.2 parts of methyl isobutyl ketone for reuse, and the water layer of 541.3 parts was cooled to 50℃ and sent to the waste treatment workshop for treatment.

[0039] (3) 1985.1 parts of a methyl isobutyl ketone solution of 2,4-methylethylphenol 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 3:1) to remove 1469.8 parts of methyl isobutyl ketone. The remaining material in the vessel was then transferred to a high-efficiency distillation column (250 theoretical trays) and vacuum distilled (-0.085 MPa, reflux ratio 35:1) to obtain 8.4 parts of 99.5% p-ethylphenol and 90.7 parts of 96.9% crude 2,4-methylethylphenol. 2.7 parts of phenol, 87.9 parts of 2,4-methylethylphenol, 151.5 parts of 99.3% 2,4-methylethylphenol, 147.9 parts of 2,4-methylethylphenol / 2,3,6-trimethylphenol (114.3 parts of 2,4-methylethylphenol, 33.6 parts of 2,3,6-trimethylphenol), and 14.9 parts of 99.2% 2,3,6-trimethylphenol were used. 82.6 parts of the reactor residue (including 79.9 parts of prepolymer) were returned to the first-step polymerization reactor and used together with the 2,4 / 2,5-methylethylphenol raw material for the next batch of phenolic resin synthesis.

[0040] Crude 2,4-methylethylphenol is used to refine 99% 2,4-methylethylphenol; a mixture of 2,4-methylethylphenol and 2,3,6-trimethylphenol is used to produce 2,3,6-trimethylphenol and the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol.

[0041] Example 2 (1) In the reactor, start stirring and add 64.6 parts of the previous batch of prepolymer, 500 parts of phenol, 200 parts of m-cresol, 200 parts of m-ethylphenol, 100 parts of m-isopropylphenol, 1240 parts of formaldehyde (the total amount of formaldehyde is 1.99 times the total molar amount of m-cresol, m-ethylphenol, m-isopropylphenol, phenol, 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol), 30 parts of oxalic acid (dissolved in 50 parts of water, the amount of oxalic acid is 1.5 wt% of the total amount of phenolic materials), and 10 parts of 85% phosphoric acid (the amount of phosphoric acid is 1.5 wt% of the total amount of phenolic materials). (0.5wt% of the total material) After feeding, the pH of the reaction solution was measured to be 2.4 using pH test paper. The reflux and venting devices were adjusted, and the steam valve was opened to raise the temperature. The reaction was carried out at 90-95℃ for 1.5 hours. Then, 1000 parts of 2,4 / 2,5-methylethylphenol (containing 45 parts of 3,5-xylenol, 101 parts of 3,4-xylenol, 86 parts of 2,4,6-trimethylphenol, 520.2 parts of 2,4-methylethylphenol, and 247.8 parts of 2,5-methylethylphenol) and 800 parts of the remaining 37% formaldehyde were added dropwise over 4 hours.

[0042] The temperature was raised to 98℃, and the reaction was started by maintaining the temperature at 98-102℃. The temperature was then stabilized at 100℃. After 4 hours of maintenance, samples were taken for analysis. Liquid chromatography analysis showed that 0.42% of 3,4-xylenol / 2,5-methylethylphenol and 14.13% of free phenol were within acceptable limits. The temperature was then slightly lowered to 70℃.

[0043] (2) Adjust the vacuum device and start vacuum dehydration. The dehydration temperature is controlled at 80-85℃ for 2 hours and the final pressure is controlled at -0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes.

[0044] (3) Gradually increase the vacuum to -0.095 MPa for 1 hour, further increase the temperature to dehydrate, and when the temperature of the material in the kettle reaches 130°C 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 1992.8 parts of xylenol resin (softening point 93.3°C, free phenol 2.2%, residual carbon 75.7%), which is off-white in color, and distillate is obtained at the same time.

[0045] (4) Add the distillate to the extraction vessel, add 5 parts of hydrochloric acid (the amount of hydrochloric acid is 0.25 wt% of the total amount of phenolic raw materials), heat to 100℃ and react for 2 hours, take a sample to analyze 0.26% of 3,4-xylenol / 2,5-methylethylphenol; then add 1500 parts of ethyl acetate (the amount of ethyl acetate is 0.75 times the total mass of phenolic raw materials), stir for 30 minutes and separate into layers, wash the oil layer once with 75 parts of water, let it stand to separate into layers, the upper layer is 2050.3 parts of ethyl acetate solution of 2,4-methylethylphenol (containing 435.7 parts of 2,4-methylethylphenol, 82.8 parts of 2,4,6-trimethylphenol, 0.5 parts of 3,4-xylenol, 1.2 parts of 2,5-methylethylphenol, and 60.1 parts of prepolymer); heat the water layer and reflux to obtain 8.9 parts of ethyl acetate for reuse, and cool the water layer to 50℃ and send it to the waste treatment workshop for treatment.

[0046] (5) 2050.3 parts of the ethyl acetate solution of 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 1:1) to remove 1452.5 parts of ethyl acetate. The remaining material in the vessel was then transferred to a high-efficiency distillation column (250 theoretical trays) and vacuum distilled (-0.085 MPa, reflux ratio 25:1) to obtain 99.1% 2,4,6-ethyl acetate. 42.7 parts of tricresol, 147.9 parts of 2,4-methylethylphenol / 2,4,6-tricresol (182.9 parts of 2,4-methylethylphenol and 36.2 parts of 2,4,6-tricresol), and 236.7 parts of 99.4% 2,4-methylethylphenol were used. 64.5 parts of the reactor residue (including 60.1 parts of prepolymer) were returned to the first-step polymerization reactor and used together with the 2,4 / 2,5-methylethylphenol raw material to synthesize the next batch of xylenol-formaldehyde resin.

[0047] A mixture of 2,4-methylethylphenol and 2,4,6-trimethylphenol is used to produce 2,4,6-trimethylphenol and the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol.

[0048] Example 3 (1) In the polymerization reactor, add 73.7 kg of the previous batch of prepolymer, 1000 kg of the first phenolic component (99.2% coal-derived phenol), 400 kg of 2,4 / 2,5-methylethylphenol fraction (containing 14.8 parts of p-ethylphenol, 16.8 parts of m-ethylphenol, 38 parts of 3,5-xylenol, 59.2 parts of 3,4-xylenol, 25.2 parts of 2,3,6-trimethylphenol, 171.2 parts of 2,4-methylethylphenol, and 74.8 parts of 2,5-methylethylphenol), 745 kg of 37% formaldehyde aqueous solution (the total amount of formaldehyde is 1.53 times the sum of the molar amounts of phenol, 3,5-xylenol, m-ethylphenol, 3,4-xylenol, and 2,5-methylethylphenol), and 10 kg of 36% hydrochloric acid (the amount of hydrochloric acid is 0.5 wt% of the total amount of phenolic materials). Adjust the pH to 1.9 and react at 90°C for 1 hour. Subsequently, 600 kg of the remaining 2,4 / 2,5-methylethylphenol fraction and 1000 kg of 37% formaldehyde aqueous solution were added dropwise over a 2-hour period. After heating to 98℃, 20 kg of 36% hydrochloric acid was added, and the reaction was maintained at this temperature for 2 hours. Sample analysis showed that the 2,5-methylethylphenol content was 0.01% and the free phenol content was 11.3%.

[0049] (2) Adjust the vacuum device and start vacuum dehydration. The dehydration temperature is controlled at 80-85℃ for 2 hours and the final pressure is controlled at -0.08Mpa. At the same time, observe the water level of the receiver. Specifically, the water level should be kept constant within 20 minutes.

[0050] (3) Gradually increase the vacuum to -0.095 MPa for 1 hour, and further increase the temperature to dehydrate. When the temperature of the material in the kettle reaches 190°C and no liquid distills out, the dehydration time is 3 hours. Continue to keep the temperature for 1 hour, stop the 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 1983.3 kg of xylenol resin (softening point 116°C, free phenol 0.6%, carbon residue 77.3%), which is off-white in color. At the same time, distillate is obtained. (4) Add 6 kg of 36% hydrochloric acid (the amount of hydrochloric acid is 0.3 wt% of the total amount of phenolic raw materials) and 5 kg of 37% formaldehyde to the distillate. After secondary polymerization at 100-105℃ for 1 hour, cool down to 60℃ and extract with 2000 kg of methyl isobutyl ketone (the amount of methyl isobutyl ketone is 1 times the total mass of phenolic raw materials) for 1 hour. Let stand for 1 hour and separate into layers. Wash the oil layer with 100 kg of water once. Heat up the water layer to recover 7.8 kg of methyl isobutyl ketone for reuse. Cool the water layer 1483 kg to 40℃ and send it to the wastewater treatment section for treatment.

[0051] (5) The oil layer is heated, and then distilled under normal pressure and then under reduced pressure (-0.05MPa, reflux ratio 2:1) to obtain 1942.7kg of methyl isobutyl ketone for reuse; then the remaining material in the reactor is transferred to a high-efficiency distillation column (250 theoretical plates) and distilled under reduced pressure (-0.085MPa, reflux ratio 30:1) to obtain 178.7kg of 99.1% 2,4-methylethylphenol, 99.7kg of a mixture of 2,4-methylethylphenol / 2,3,6-trimethylphenol (of which 81.5kg of 2,4-methylethylphenol and 18.2kg of 2,3,6-trimethylphenol), and 16.1kg of 99.2% 2,3,6-trimethylphenol, and 73.4kg of reactor residue (prepolymer) is reused in the next batch of phenolic resin synthesis reaction.

[0052] Example 4 Step 1: Synthesis of 4-ethyl-2-cresol, 5-ethyl-2-cresol, and 3-ethyl-2-cresol: 1200 parts of chemically pure ammonium metavanadate, 3000 parts of ferric nitrate, 600 parts of aluminum nitrate, and 200 parts of nickel nitrate were added to a preparation vessel and dissolved in 24000 parts of distilled water under stirring. Ammonia water was added dropwise to adjust the pH to 7-9. The resulting precipitate was aged for 1-2 hours, then filtered, washed, and dried. 4000 parts of silica sol (30%) and 40 parts of silane coupling agent KH560 were added and mixed. The mixture was then extruded into strip-shaped catalysts with a diameter of 1-2 mm and a length of 2-3 mm. The catalysts were then dried at 110-120℃ for 12 hours and calcined at 500-800℃ for 8 hours to obtain 2953 parts of a catalyst composed of iron alum aluminum nickel oxide. The V:Fe:Al:Ni ratio in the obtained catalyst was 0.83:1:0.23:0.07 (mol).

[0053] Sixty parts of a catalyst prepared by supporting iron oxide on silica gel was packed into a fixed-bed reactor. A mixture of 10,000 parts of a m- and p-ethylphenol mixture (containing 4,984 parts of m-ethylphenol, 3,606 parts of p-ethylphenol, and 1,410 parts of 3,5-xylenol), 7,870 parts of methanol, and 1,620 parts of water (3.0 and 1.1 times the molar amounts of the m- and p-ethylphenol mixture, respectively) was injected into the reactor via a plunger metering pump through a preheater. The reactor was operated at atmospheric pressure, 270°C, and a liquid hourly space velocity (LHSV) of 1.2 h⁻¹. -1The reaction was carried out under the following conditions: 4-ethyl-2-cresol 24.6%, 5-ethyl-2-cresol 25.3%, 4-ethyl-2,6-dimethylphenol 0.38% / 3-ethyl-2,6-dimethylphenol 0.41% were qualified. The resulting condensate was added to a distillation column (theoretical trays approximately 200). Distillation was carried out at atmospheric pressure and a reflux ratio of 2:1 to obtain 5907.9 parts of methanol, which was reused. Distillation was carried out at -0.05 MPa and a reflux ratio of 3 to 5:1 to recover 2549.6 parts of water. Part of the recovered water was reused in the next batch of methylation reaction; the unused recovered water was sent for further treatment. Distillation was carried out at -0.085 to -0.09 MPa and a reflux ratio of 20 to 25:1 to obtain 2630.9 parts of m- and p-ethylphenol (including 1008.5 parts of p-ethylphenol, 1437.8 parts of m-ethylphenol, and 184.6 parts of 3,5-dimethylphenol) and 1 part of middle fraction. 1608.1 parts (including 284.4 parts of p-ethylphenol, 405.5 parts of m-ethylphenol, 52 parts of 3,5-xylenol, 451.5 parts of 4-ethyl-2-cresol, and 414.7 parts of 5-ethyl-2-cresol), 3162 parts of a mixture of 4-ethyl-2-cresol and 5-ethyl-2-cresol (including 1555.2 parts of 4-ethyl-2-cresol and 1606.8 parts of 5-ethyl-2-cresol), and 21236.5 parts of middle distillate (including 4-ethyl-2-cresol). 551.8 parts, 570.2 parts, 114.5 parts, 99.1% 3-ethyl-2-cresol 436.8 parts, 2,3,5-trimethylphenol / 3-ethyl-2-cresol mixture 485.1 parts (3-ethyl-2-cresol 131.8 parts, 2,3,5-trimethylphenol 313.3 parts), 99.3% 2,3,5-trimethylphenol 736.2 parts, 99.1% 3-ethyl-4-cresol 113.1 parts.

[0054] Step 2: Separation of the 4-ethyl-2-cresol / 5-ethyl-2-cresol mixture to produce thermoplastic phenolic resin and pesticide intermediate 4-ethyl-2-cresol: In a polymerization reactor, 8.1 parts of prepolymer, 3162 parts of the 4-ethyl-2-cresol / 5-ethyl-2-cresol mixture obtained in the first step (1555.2 parts of 4-ethyl-2-cresol and 1606.8 parts of 5-ethyl-2-cresol), and 100 parts of oxalic acid (3.16 wt% of the total phenolic materials, with 150 parts of water as solvent) were added. The mixture was stirred and heated to 95–100°C. 1942 parts of a 36.5% formaldehyde aqueous solution were then added dropwise (the amount of formaldehyde was twice the molar amount of 5-ethyl-2-cresol in the 4-ethyl-2-cresol / 5-ethyl-2-cresol mixture). The addition time was 4 hours. After the addition was completed, the mixture was kept at 95–100°C for 5 hours, and samples were taken for analysis. The 5-ethyl-2-cresol content was 0.12%.

[0055] Adjust the vacuum device and start vacuum dehydration. After the system stabilizes, dehydrate at -0.075 to -0.09 MPa and 80 to 85°C for 2.5 hours. Gradually increase the vacuum to -0.098 MPa while further increasing the temperature for dehydration. When the material temperature in the reactor reaches 220°C and no liquid distills out, keep it at that temperature for 1 hour, stop dehydration, release the vacuum with nitrogen, and under nitrogen protection, release the hot material into a stainless steel pan to cool, then crush and bag it to obtain 2462.8 parts of linear ethyl phenol formaldehyde resin, which is off-white in color, contains 0.07% free phenol, and has a softening point of 112°C.

[0056] The distilled material was added to an extraction vessel, along with 10 parts of oxalic acid (0.32 wt% of the total phenolic raw material) and 2 parts of 36% hydrochloric acid (0.06 wt% of the total phenolic raw material). The mixture was heated to 100°C and reacted for 2 hours. Then, the temperature was lowered to 60°C, and 2200 parts of methyl isobutyl ketone (0.63 times the total mass of the phenolic raw material) were added. The mixture was kept at 60°C and stirred for 1 hour. After standing for 1 hour, the layers separated. The oil layer was washed once with 100 parts of water, and the mixture was allowed to stand for further separation. The lower water layer was heated to remove impurities. 9.3 parts of methyl isobutyl ketone were used to cool 1719.8 parts of the aqueous layer to 40°C and send it to the wastewater treatment section. The upper oil layer was added to a distillation vessel with 100 trays and distilled (0 to -0.05 MPa, reflux ratio 2:1) to remove 2156 parts of solvent for reuse. Reduced pressure distillation (-0.085 MPa, reflux ratio 10) yielded 1167.7 parts of 99.6% 4-ethyl-2-cresol. The residue of 8.3 parts (prepolymer) can be returned to be mixed with 4-ethyl-2-cresol and 5-ethyl-2-cresol raw materials for the next batch of phenolic resin synthesis.

[0057] Example 5 (1) In the polymerization reactor, start stirring and add 94.1 parts of prepolymer, 500 parts of 2,4 / 2,5-methylethylphenol (containing 18.5 parts of p-ethylphenol, 21 parts of m-ethylphenol, 47.5 parts of 3,5-xylenol, 74 parts of 3,4-xylenol, 31.5 parts of 2,3,6-trimethylphenol, 214 parts of 2,4-methylethylphenol, and 93.5 parts of 2,5-methylethylphenol), 150 parts of 25% ammonia (3.75 wt% of the total phenol content), and 300 parts of 37% formaldehyde (the total formaldehyde content is m-ethylphenol, 2,5-... (The total molar mass of methyl ethyl phenol, 3,5-xylenol, and 3,4-xylenol is 1.99 times). After feeding, adjust the reflux and venting devices, open the steam valve to raise the temperature, start the stirrer, and heat slowly to 90-95℃. Maintain the temperature for 1 hour, then start adding 300 parts of the remaining 37% formaldehyde and simultaneously add 500 parts of the remaining 2,4 / 2,5-methyl ethyl phenol. The addition is completed in 2 hours. Start maintaining the temperature for 5 hours and take samples for analysis. Liquid chromatography analysis shows that 2.1% of 3,4-xylenol / 2,5-methyl ethyl phenol and 29.32% of free phenol are qualified.

[0058] (2) After the reaction is completed, gradually open the vacuum to -0.08MPa over 1 hour to dehydrate. First, separate the dehydrated water and phenol through the water separator on the reactor and return it to the reactor. Observe the dehydration rate slowing down or until the temperature drops to about 75℃. Then heat and continue dehydration. After dehydration for 1.5 hours, put all the distilled material into the phenol water receiving tank and dehydrate for another 2 hours. (3) Increase the dehydration vacuum to -0.98MPa and continue distilling until no liquid distills out at 120℃. Continue to keep warm for 0.5 hours, stop dehydration, remove the vacuum with nitrogen, and while hot, put the material into a stainless steel pan for cooling under nitrogen protection. Then crush and bag it to obtain 730.5 parts of xylenol resin (softening point 92.3℃, free phenol 2.1%), which is white in color. At the same time, distillate is obtained.

[0059] (4) Add 5 parts of 36% hydrochloric acid (the amount of hydrochloric acid is 0.5 wt% of the total amount of phenolic raw materials) and 8 parts of 37% formaldehyde to the distilled water, heat to 100-103℃ and react for 1 hour. Take a sample for analysis. The 3,4-xylenol / 2,5-methylethylphenol content of 0.19% is qualified. After 0.5 hours, cool the material to 60℃, and then add 2000 parts of methyl isobutyl ketone (the amount of methyl isobutyl ketone is twice the total mass of phenolic raw materials). Stir for 1 hour and let stand for 0.5 hours. The mixture was separated into layers. The lower water layer was heated to recover 2.8 parts of methyl isobutyl ketone and then sent to the wastewater treatment workshop for treatment (approximately 574.2 parts). The upper oil layer was washed once with 100 parts of water. The resulting oil layer was an unreacted phenolic methyl isobutyl ketone solution of 2484.4 parts (containing 14.3 parts of p-ethylphenol, 355.8 parts of 2,4-methylethylphenol, 52.1 parts of 2,3,6-trimethylphenol, 0.4 parts of 3,4-dimethylphenol, 0.6 parts of 2,5-methylethylphenol, and 91.2 parts of prepolymer).

[0060] (5) 2484.4 parts of a methyl isobutyl ketone solution of 2,4-methylethylphenol were added to a distillation vessel with 20 trays. The temperature was raised first to atmospheric pressure and then to vacuum distillation (-0.05 MPa, reflux ratio 3:1) to remove 1953.8 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 35:1) to obtain 7.1 parts of 99.2% p-ethylphenol and 90.7 parts of 95.37% crude 2,4-methylethylphenol. The following components were prepared: 4.1 parts of methylphenol, 86.5 parts of 2,4-methylethylphenol, 155.8 parts of 99.3% 2,4-methylethylphenol, 147.9 parts of 2,4-methylethylphenol / 2,3,6-trimethylphenol (108.6 parts of 2,4-methylethylphenol and 31.8 parts of 2,3,6-trimethylphenol), and 16.8 parts of 99.4% 2,3,6-trimethylphenol. 94.3 parts of the reactor residue (including 91.2 parts of prepolymer) were returned to the first-step polymerization reactor to be used together with the 2,4 / 2,5-methylethylphenol raw material for the next batch of phenolic resin synthesis.

[0061] Crude 2,4-methylethylphenol is used to refine 99% 2,4-methylethylphenol; a mixture of 2,4-methylethylphenol and 2,3,6-trimethylphenol is used to produce 2,3,6-trimethylphenol and the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol.

[0062] Example 6 (1) In the polymerization reactor, start stirring and add 58.9 parts of prepolymer and 130 parts of 31% liquid alkali (4wt% of the total mass of phenol) in sequence. After feeding is completed, adjust the reflux and venting devices, open the steam valve to raise the temperature, start stirring, heat to 85-90℃, and start adding 1000 parts of 2,4 / 2,5-methylethylphenol (containing 45 parts of 3,5-xylenol, 101 parts of 3,4-xylenol, and 2,4,6-trimethylphenol). 86 parts of 2,4-methylethylphenol, 520.2 parts of 2,5-methylethylphenol, and 247.8 parts of 37% formaldehyde (the total amount of formaldehyde used is 1.99 times the total molar mass of 2,5-methylethylphenol, 3,5-xylenol, and 3,4-xylenol) were added dropwise over 2 hours. The reaction was then kept at a constant temperature for 3 hours before sampling and analysis. Liquid chromatography analysis showed that 0.7% of 3,4-xylenol / 2,5-methylethylphenol and 35.58% of free phenol were within acceptable limits.

[0063] (2) After the reaction is complete, add 61 parts of glacial acetic acid to neutralize to pH 6. Gradually increase the vacuum to -0.09 MPa over 1.5 hours for dehydration. First, separate the dehydrated water and free phenol through the water separator on the reactor, then return the water to the reactor. Observe the dehydration rate until it slows down or the temperature drops to about 70-75℃. Then, heat and continue dehydration. After dehydration for 1.5 hours, transfer all the distilled material into the receiving tank. Dehydrate for about another 2.5 hours. The liquid temperature in the reactor is 80-85℃. Take a sample for analysis. The moisture content of the material is 3.3%, which is qualified. (3) Add 25 parts of ethylene glycol, stir evenly, take a sample to analyze the moisture and viscosity. Stop vacuuming when the moisture content is 3.1%, and add 10 parts of ethanol to adjust the viscosity to 15 Pa·s. Cool down to 50℃ and discharge to obtain 764.1 parts of material. Test the free phenol content of 6.2%, free aldehyde content of 0.98%, solid content of 80.8%, residual carbon content of 48.9%, moisture content of 3.0%, and viscosity to 15 Pa·s.

[0064] (4) Add 5 parts of 36% hydrochloric acid to the distilled water (the amount of hydrochloric acid is 0.5wt% of the total amount of phenolic raw materials), heat to 100℃ and react for 1 hour. Take a sample for analysis. 0.14% of 3,4-xylenol / 2,5-methylethylphenol is qualified. After 0.5 hours, cool the material to 60℃ and add 2000 parts of toluene (the amount of toluene is twice the total mass of phenolic raw materials). Stir for 1 hour, let stand for 0.5 hours, and separate into layers. After heating the lower water layer to recover 2.6 parts of toluene, send it to the wastewater treatment workshop for treatment (about 446.3 parts). Wash the upper oil layer with 100 parts of water once. The oil layer obtained by separation is 2518.1 parts of unreacted phenolic toluene solution (containing 412.4 parts of 2,4,6-trimethylphenol, 79.2 parts of 3,4-xylenol, 0.2 parts of 2,5-methylethylphenol, and 55.9 parts of prepolymer).

[0065] (5) 2518.1 parts of a toluene solution of 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 1:1) to remove 1952.5 parts of toluene. The remaining material in the vessel was then transferred to a high-efficiency distillation column (250 theoretical trays) and vacuum distillation (-0.085 MPa, reflux ratio 25:1) to obtain 99.3% 2,4,6-trimethylphenol. 37.3 parts of phenol, 206.6 parts of 2,4-methylethylphenol / 2,4,6-trimethylphenol (165.8 parts of 2,4-methylethylphenol and 38.8 parts of 2,4,6-trimethylphenol), and 236.4 parts of 99.2% 2,4-methylethylphenol were added. 59.1 parts of the reactor residue (including 55.9 parts of prepolymer) were returned to the first-step polymerization reactor and used together with the 2,4 / 2,5-methylethylphenol raw materials to synthesize the next batch of xylenol-formaldehyde resin.

[0066] A mixture of 2,4-methylethylphenol and 2,4,6-trimethylphenol is used to produce 2,4,6-trimethylphenol and the polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol.

[0067] Example 7 (1) In the polymerization reactor, start stirring and add 32.7 parts of prepolymer, 1000 parts of molten coal-derived 99.2% phenol, 400 parts of 2,4 / 2,5-methylethylphenol (containing 14.8 parts of p-ethylphenol, 16.8 parts of m-ethylphenol, 38 parts of 3,5-xylenol, 59.2 parts of 3,4-xylenol, 25.2 parts of 2,3,6-trimethylphenol, 171.2 parts of 2,4-methylethylphenol, and 74.8 parts of 2,5-methylethylphenol), 258 parts of 31% liquid alkali (4wt% of the total phenol raw material), and 745 parts of 37% formaldehyde (the total formaldehyde content is phenol, m-ethylphenol, 3,5-xylenol, 3,4-xylenol, 2,5-xylenol, and 2,5-xylenol). (1.5 times the total molar mass of methyl ethyl phenol), after feeding, adjust the reflux and venting devices, open the steam valve to raise the temperature, start the stirrer, heat, raise the temperature to 40-50℃, open the jacket cooling water to remove the heat of reaction at around 50-60℃, slowly raise the temperature to 80-85℃, keep the reaction at this temperature for 2 hours, start adding 1000 parts of the remaining 37% formaldehyde dropwise, and simultaneously add 600 parts of the remaining 2,4 / 2,5-methyl ethyl phenol dropwise, complete the addition in 2 hours, start the reaction at this temperature, keep the reaction at this temperature for 5 hours, take a sample for analysis, liquid chromatography analysis shows that the m-phenol content is 0.3% (m-phenol is m-ethyl phenol, 3,5-xylenol, 3,4-xylenol, 2,5-methyl ethyl phenol) and the free phenol content is 11.4%, which is qualified.

[0068] (2) After the reaction is complete, add 121 parts of glacial acetic acid to neutralize to pH 6.5. Gradually open the vacuum to -0.09 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 hour and 20 minutes. 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 2.9%, which is qualified. (3) Add 60 parts of ethylene glycol, stir evenly, take samples to analyze moisture and viscosity. Stop vacuuming when the moisture content is 2.7%, and add 25 parts of ethanol to adjust the viscosity to 16 Pa.s. Cool down to 50℃ and discharge 2262.5 parts of material. Test the free phenol content of 4.1%, free aldehyde content of 0.72%, solid content of 81.1%, residual carbon content of 49.8%, moisture content of 2.7%, and viscosity to 17 Pa.s.

[0069] (4) Add 2 parts of 36% hydrochloric acid to the distilled water (the amount of hydrochloric acid is 0.1 wt% of the total amount of phenolic raw materials), heat to 100℃ and react for 1 hour. Take a sample for analysis. The 3,4-xylenol / 2,5-methylethylphenol content of 0.6% is unqualified. Add 6 parts of 37% formaldehyde and continue to react for 1 hour. Take a second sample for analysis. The 3,4-xylenol / 2,5-methylethylphenol content of 0.16% is qualified (free aldehyde content of 0.2%). After 0.5 hours, cool the material to 60℃ and add 2000 parts of toluene (the amount of toluene is 0.1 wt% of the total amount of phenolic raw materials). The mixture was stirred for 1 hour and allowed to stand for 0.5 hours. After separation, the lower water layer was heated to recover 9.8 parts of toluene and then sent to the wastewater treatment workshop (1539.2 parts). The upper oil layer was washed once with 100 parts of water. The resulting oil layer was a solution of unreacted phenolic substances in toluene, consisting of 2326.2 parts of p-ethylphenol, 0.7 parts of 3,4-xylenol, 42.3 parts of 2,3,6-trimethylphenol, 274 parts of 2,4-methylethylphenol, 1.9 parts of 2,5-methylethylphenol, and 29.1 parts of prepolymer.

[0070] (5) 2326.2 parts of the obtained oil layer 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 3:1) to distill off 1941 parts of solvent. The material in the distillation vessel was transferred to a high-efficiency rectification vessel with 250 trays and distilled (-0.085 MPa, reflux ratio 20:1) to obtain 11.9 parts of 99.5% p-ethylphenol and 222.1 parts of 95.3% 2,4-methylethylphenol (211.8 parts of 2,4-methylethylphenol). The following components were used: 1.4 parts of 2,5-xylenol, 8.3 parts of 2,3,6-trimethylphenol, and 0.6 parts of other phenols; 50.5 parts of 2,4-methylethylphenol / 2,3,6-trimethylphenol (32.2 parts of 2,4-methylethylphenol, 17.9 parts of 2,3,6-trimethylphenol, and 0.3 parts of other phenols); 20.2 parts of 99.2% 2,3,6-trimethylphenol; and 32.9 parts of residue from the reactor bottom (3.8 parts of phenol and 29.1 parts of prepolymer). The prepolymer was returned to the polymerization reactor for the next batch of phenolic resin synthesis.

[0071] 2,4-Methylethylphenol / 2,3,6-trimethylphenol is produced by tert-butylation reaction to yield 99.5% high-efficiency polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol and pharmaceutical intermediate 99.5% 2,3,6-trimethylphenol. 95.3% 2,4-Methylethylphenol is also produced by tert-butylation reaction to yield 99.5% high-efficiency polymerization inhibitor 6-tert-butyl-2,4-methylethylphenol.

[0072] Comparative Example 1 (1) In the reactor, start stirring and add 2000 parts of 99.9% molten petrochemical grade phenol and 23 parts of oxalic acid (25 parts dissolved in hot water) in sequence. After feeding, use pH test paper to determine that the pH of the reaction solution is 3.5-4. Adjust the reflux and venting devices, and the liquid temperature is 51℃. Open the steam valve to raise the temperature. The steam pressure should not exceed 0.3Mpa. Gradually add 1535 parts of 37% formaldehyde (the amount of formaldehyde is 0.89 times the molar amount of phenol) at 90℃. The addition time is 2 hours. After adding, slowly raise the temperature. The heating rate should be strictly controlled within 1.5℃ / min. The rate should be determined to be 1.0℃ / min to avoid the temperature rising too fast, which would cause the reaction solution to overflow and affect the resin quality.

[0073] (2) Heat to 95℃ and start the reaction. The reaction temperature is controlled at 95-100℃ and stabilized at 98℃. After 4 hours of heat preservation, take a sample for analysis. Gel chromatography analysis shows phenol content of 13.6%. Open the valve of the condenser and separator system, reflux water vapor distillation to remove water, continuously separate the oil layer at the bottom of the separator, and return the upper water layer back into the kettle. After observing that there is no obvious oily substance in the condensate, heat to 120℃ to remove most of the water, and then cool down slightly.

[0074] (3) Cool the reactants to 80°C, adjust the vacuum device, start vacuum dehydration, control the dehydration temperature at 80-85°C, control the time at 3 hours, control the final pressure at -0.075--0.08 MPa, and observe the water level in the receiver at the same time. Specifically, the water level should be kept constant within 20 minutes.

[0075] The pre-dehydrated material was divided into two portions and processed as follows: One batch of phenolic resin was gradually vacuumed to -0.090 MPa for 2 hours, while the temperature was further increased for dehydration. When the temperature of the material in the reactor reached 120°C and no liquid distilled out, it was kept at this temperature for 1 hour, and then dehydration was stopped. The vacuum was released with nitrogen, and the material was discharged while hot into a stainless steel pan under nitrogen protection. After cooling, it was crushed and bagged to obtain 1037 parts of phenolic resin (softening point 96.7°C, free phenol 2.3%, residual carbon 72.8%), with a color of off-white to pale yellow.

[0076] A batch of thermoplastic phenolic resin was gradually increased to -0.095 MPa for 1 to 2 hours, while the temperature was further increased for dehydration. When the temperature of the material in the reactor reached 200°C and no liquid distilled out, the temperature was maintained for 1 hour, and dehydration was stopped. The vacuum was released with nitrogen, and the material was discharged while hot into a stainless steel pan under nitrogen protection, cooled, crushed, and bagged to obtain 987.9 parts of thermoplastic phenolic resin (softening point 119.1°C, free phenol 0.5%, residual carbon 75.9%), with a color of off-white to pale yellow.

[0077] A total of 1,472 portions of liquid were extracted during the entire process.

[0078] Comparative Example 2 (1) In a 6300L enamel-lined reactor with a jacket, 2400kg of 99.9% petrochemical phenol, 36kg of sodium hydroxide, and 3060kg of 36.5% formaldehyde are fed in sequence (sodium hydroxide is dissolved in 60kg of water). Steam is passed through the jacket to raise the temperature. When the temperature reaches about 40-45℃, the steam is turned off. When the temperature reaches about 50-55℃, the steam in the jacket is turned off again. The steam in the jacket is discharged. A suitable amount of cooling water is passed through, and the temperature is slowly raised to 80-85℃. The reaction is kept at this temperature for 2 hours. It is important to pay close attention to the temperature changes of the materials before and after turning on and off the steam and cooling water.

[0079] (2) After the reaction is complete, add 39.7 kg of glacial acetic acid to neutralize to pH 6.5. Maintain this for 10 minutes and take a sample to retest the pH. Start dehydration. Gradually control the vacuum to -0.075 MPa over 1 hour. Observe the dehydration speed slowing down and the temperature dropping to 70℃. Turn on the jacket steam heating. During dehydration, continuously adjust the steam switch according to the water output speed to ensure that dehydration is completed at the lowest possible temperature. Continue to pass steam in the later stage of dehydration and control the final liquid temperature at 80℃. When the water level reaches the required value (2269.8 kg), take a sample to analyze the water content and viscosity. Stop vacuuming when the water content is 2.8%. Add 150 kg of ethylene glycol and stir for 0.5 hours. Take a sample with a viscosity of 24 Pa·s. Then use 24 kg of anhydrous ethanol to adjust the viscosity to 15 Pa·s.

[0080] (3) After the viscosity reaches the requirement, the temperature is lowered to 50℃ and the material is discharged, yielding 3382 kg of liquid material. The test results showed that the free phenol content was 8.6%, the free aldehyde content was 1.18%, the solid content was 75.3%, the residual carbon content was 45.2%, the moisture content was 2.7%, and the viscosity was 15 Pa·s.

[0081] Based on the results of Examples 1-7 and Comparative Examples 1-2, the phenolic resin synthesized using a mixture of 2,4 / 2,5-methylethylphenol (such as phenol, m-cresol, m-ethylphenol, m-isopropylphenol, etc.) and formaldehyde under the action of an acidic or alkaline catalyst has similar properties to the phenolic resin synthesized using petrochemical phenol. Therefore, it can replace petrochemical phenol in the production of general-purpose phenolic resin, while significantly reducing the resin production cost.

[0082] 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.

[0083] 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 2,4 / 2,5-methylethylphenol, characterized in that, Includes the following steps: (1) Add a portion of 2,4 / 2,5-methylethylphenol, a portion of aldehydes and the first catalyst to the polymerization reactor, start stirring, heat to 80-105℃ and react for 1-6 hours, add the remaining 2,4 / 2,5-methylethylphenol and the remaining aldehydes dropwise at 80-105℃ for 1-4 hours, keep warm for 1-6 hours after addition and take samples for analysis. The 2,5-methylethylphenol content ≤5% is qualified. (2) Cool down to 60-80℃ and start vacuum dehydration. The dehydration temperature is 80-85℃ and the dehydration time is 2-5 hours. The final pressure is -0.075--0.08Mpa. At the same time, observe the water level of the receiver and take the water level as 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 reactor reaches 100 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 2,5-methylethylphenol aldehyde resin.

2. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol 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, a mixture of m-isopropylphenol and m-propylphenol, 3,5-xylenol, phenol, or 3-ethyl-5-cresol. And / or, in step (1), the amount of the first phenolic component is 0.1 to 200 wt% of 2,4 / 2,5-methylethylphenol.

3. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to claim 1, characterized in that, In step (1), the 2,4 / 2,5-methylethylphenol is obtained by distillation of crude phenol extracted from coal coking crude phenol, medium-low temperature coal gasification crude phenol, or crude phenol extracted from phenol-containing coal tar by coal pyrolysis. And / or, in step (1), the 2,4 / 2,5-methylethylphenol comprises 60-100 wt% 2,4 / 2,5-methylethylphenol, 0-30 wt% 3,5-dimethylphenol, 0-20 wt% m-p-ethylphenol, 0-30 wt% 3,4-dimethylphenol, 0-10 wt% 2,3,6-trimethylphenol, 0-20 wt% m-p-isopropylphenol, wherein the 2,4 / 2,5-methylethylphenol is a mixture of 4-ethyl-2-methylphenol, 2-ethyl-4-methylphenol, 5-ethyl-2-methylphenol and 2-ethyl-5-methylphenol, or a mixture of 4-ethyl-2-methylphenol and 5-ethyl-2-methylphenol, or a mixture of 2-ethyl-4-methylphenol and 2-ethyl-5-methylphenol.

4. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to claim 3, characterized in that, In step (1), the aldehydes include at least one of paraformaldehyde, formaldehyde, or acetaldehyde, and the molar amount of the aldehydes is 1 to 2.5 times the sum of the molar amounts of phenol, m-cresol, 3,5-xylenol, m-ethylphenol, m-isopropylphenol, m-propylphenol, 3-ethyl-5-cresol, 3,4-xylenol, and 2,5-methylethylphenol. And / or, in step (1), a portion of the 2,4 / 2,5-methylethylphenol is 0 to 100 wt% of the total amount of 2,4 / 2,5-methylethylphenol, and a portion of the aldehyde is 0 to 100 wt% of the total amount of aldehyde.

5. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to claim 1, characterized in that, In step (1), the first catalyst includes at least one of oxalic acid, formic acid, phosphoric acid, hydrochloric acid, aminosulfonic acid, benzenesulfonic acid, ammonia or organic base, 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 2,4 / 2,5-methylethylphenol according to claim 1, characterized in that, In step (1), the first catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, or ammonia water, and 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. Observe the dehydration rate as it slows down or until the temperature drops to around 70-75°C, then continue the dehydration process by heating, controlling the final liquid temperature at 70-90°C, until the water level reaches the required value, and taking a sample for analysis to determine the moisture content of the material is ≤5%. Step (3) involves adding ethylene glycol after the dehydration treatment is qualified, stirring evenly, taking samples to analyze the moisture and viscosity, stopping the vacuuming when the moisture content is 2-5%, adding ethanol to adjust the viscosity to 10-30 Pa·s, cooling to 40-50℃ and discharging to obtain liquid 2,5-methylethylphenol aldehyde resin.

7. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to claim 5 or 6, characterized in that, The process also includes step (4), adding a second catalyst to the distilled material, heating it to 80-105℃ and reacting for 1-3 hours, taking a sample for analysis to find that 2,5-methylethylphenol is ≤0.5%, then adding a non-water-soluble solvent, stirring for 0.5-2 hours, letting it stand for 0.5-1 hours, separating the layers, heating the lower water layer to 95-105℃ to remove a small amount of solvent, and then cooling the water layer after solvent removal to 40-50℃ and sending it to the wastewater treatment section for treatment, and the upper oil layer is a solution of unreacted 2,4-methylethylphenol.

8. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol 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, and the basic catalyst includes at least one of sodium hydroxide, potassium hydroxide, sodium carbonate or ammonia water. The amount of the second catalyst is 0.01 to 0.5 wt% of the total amount of phenolic raw materials.

9. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol 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 mass of the phenolic raw materials.

10. The method for synthesizing phenolic resin from 2,4 / 2,5-methylethylphenol according to claim 7, characterized in that, The oil layer is added to a distillation vessel with 5 to 30 trays. The temperature is raised first to atmospheric pressure and then to reduced pressure to remove the solvent. The material in the distillation vessel is transferred to a high-efficiency distillation vessel with 50 to 250 trays. The distillation yields 99% 4-ethyl-2-cresol or 99% 2,4-methylethylphenol or 2,4-methylethylphenol / 2,4,6-trimethylphenol. The residue in the distillation vessel, together with the 2,4 / 2,5-methylethylphenol raw material, 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 5):

1. The pressure of the rectification is -0.07 to -0.1 MPa, and the reflux ratio is (5 to 40):1.