Method for synthesizing anisole products by using cresol fraction

Abstract

The invention provides a method for synthesizing anisole products by using cresol fractions, which comprises the following steps: taking cheap cresol fractions as raw materials, and carrying out etherification reaction on the cresol fractions and an alkylating agent under the action of a basic catalyst to obtain a mixture of various methyl anisole and dimethyl anisole which are insoluble in water; and then various anisole products are obtained through a series of treatment means such as rectification treatment, tert-butylation separation and isobutene removal. According to the method, cresol with low price is adopted to replace pure phenol such as refined o-cresol, pure 2, 6-xylenol, m-cresol, p-cresol, 2, 4-xylenol, 2, 5-xylenol and the like to produce corresponding alkyl etherates, so that the economic benefit is very considerable; and the method is simple and easy to implement, the operability of the process is good, the usability is high, and the method is convenient to popularize and apply in industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of coal coking and organic chemical product production and separation, and in particular, relates to a method for synthesizing anisole products by utilizing cresol fractions. Background Art

[0002] Anisole products such as m-methylanisole, p-methylanisole, o-methylanisole and 2,6-dimethylanisole are important organic synthesis intermediates, and are often produced using expensive m-cresol, p-cresol, refined o-cresol and pure 2,6-dimethylphenol.

[0003] Existing fixed-bed catalytic methyl etherification methods require low phenol conversion or high-temperature, high-efficiency catalysts to achieve high etherification selectivity. This method suffers from disadvantages such as low yield, high energy consumption, and high production costs. Furthermore, the raw materials used are primarily pure phenol, with some specific mixed phenols. The majority of the mixed phenol synthesis and extraction results in a mixture of phenolic ethers, without the need for m-p-methylanisole separation. Separating the ethers by distillation is therefore extremely difficult. Consequently, this method is difficult to commercialize and apply industrially.

[0004] Existing production technologies for anisole, methyl anisole, dimethyl anisole, and ethyl anisole use alkaline water as a catalyst. The reaction of the raw materials, pure phenols, with dimethyl sulfate produces a large amount of wastewater high in salt and organic matter, resulting in high wastewater treatment costs and environmental concerns. Furthermore, due to the high price of pure phenols, the resulting products, such as m-methyl anisole, p-methyl anisole, o-methyl anisole, and 2,6-dimethyl anisole, are costly to produce and have limited market competitiveness.

[0005] In view of this, this application is hereby filed. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, an embodiment of the present invention provides a method for synthesizing anisole products using cresol fractions.

[0007] The embodiment of the present invention provides a method for synthesizing anisole products using cresol fractions, comprising the following steps:

[0008] (1) adding an alkaline catalyst and a protective agent to the cresol fraction, heating and stirring, and then adding an alkylating agent to carry out an etherification reaction, and then standing and stratifying the reaction product, washing, to obtain a material layer;

[0009] (2) subjecting the material layer obtained in step (2) to a rectification treatment to obtain o-methyl anisole, a first mixed fraction, 2,6-dimethyl anisole, a second mixed fraction, 2,4 / 2,5-dimethyl anisole, and a first still residue;

[0010] (3) adding sulfuric acid to the first mixed fraction obtained in step (2), stirring and heating, and then introducing isobutylene to carry out heat-insulating reaction, and then adding liquid alkali to neutralize to a pH of 7 to 8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 4-tert-butyl-2,6-dimethylanisole, a first transition fraction, mixed di-tert-butylanisole, a second transition fraction, 4,6-di-tert-butyl-2-ethylanisole, a third transition fraction, and a second still residue;

[0011] (4) adding concentrated sulfuric acid to the 4-tert-butyl-2,6-dimethylanisole, the mixed di-tert-butylanisole, and the 4,6-di-tert-butyl-2-ethylanisole obtained in step (3), stirring and heating, and reacting them respectively. After the reaction is completed, adding alkali solution to the reaction product to neutralize it to a pH of 7 to 8, separating the layers, and subjecting the obtained material layers to vacuum distillation to obtain 2,6-dimethylanisole, o-methylanisole, p-methylanisole, o-ethylanisole, and isobutylene;

[0012] (5) adding sulfuric acid to the 2,4 / 2,5-dimethylanisole obtained in step (2), stirring and heating, then introducing isobutylene to carry out heat-insulating reaction, then adding liquid alkali to neutralize to a pH of 7-8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 6-tert-butyl-2,4-dimethylanisole, a fourth transition fraction, and a third still residue; then adding concentrated sulfuric acid to the 6-tert-butyl-2,4-dimethylanisole, stirring and heating to react, and adding alkali solution to the reaction product to neutralize to a pH of 7-8, separating the layers, and rectifying the obtained material layer under reduced pressure to obtain 2,4-dimethylanisole and isobutylene.

[0013] In some embodiments, in step (1), the cresol fraction comprises 0.1-60% o-cresol, 0.1-25% 2,6-dimethylphenol, 30-100% m-para-cresol, 0.1-20% 2,4 / 2,5-dimethylphenol, and 0.1-20% o-ethylphenol;

[0014] and / or, the alkaline catalyst comprises at least one of an aqueous solution of an alkali metal or alkaline earth metal hydroxide, an organic amine substance or an alkaline substance supported on a carrier, an alkali metal or alkaline earth metal halide, and a mixture of a water-insoluble metal carbonate;

[0015] And / or, the protective agent is at least one of the antioxidant BHT, antioxidant BHA, and 6-tert-butyl-2,4-dimethylphenol;

[0016] And / or, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, di-fatty sulfates or di-fatty carbonates.

[0017] In some embodiments, in step (1), the mass ratio of the phenolic substances in the cresol fraction to the protective agent is 1:(0.0001-0.02);

[0018] And / or, the molar ratio of the phenolic substances in the cresol fraction to the alkylating agent is 1:(0.5-5).

[0019] In some embodiments, in step (1), the heating and stirring temperature is 30 to 80° C., and the stirring time is 0.5 to 2 h;

[0020] And / or, the reaction temperature of the etherification reaction is 0-200° C., the reaction time is 2-20 h, and the pressure required for the etherification reaction is 0-8 MPa; preferably, the reaction temperature of the etherification reaction is 40-150° C., and the pressure required for the etherification reaction is 0-1 MPa.

[0021] In some embodiments, in step (1), the static stratification is carried out at 70-90°C;

[0022] And / or, the washing includes: adding sulfuric acid solution to the material layer obtained after standing and stratifying, washing for 0.5 to 2 hours, and then washing the obtained material layer with water after stratification, and removing the washing water to obtain the material layer.

[0023] In some embodiments, in step (2), the theoretical plate of the distillation treatment is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (10 to 30):1.

[0024] In some embodiments, in step (3), the amount of sulfuric acid added is 1 to 5% of the mass of the first mixed fraction;

[0025] And / or, the amount of isobutylene introduced is 1 to 3 times the mass of the first mixed fraction, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 30):1.

[0026] In some embodiments, in step (4), the stirring and heating temperature is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-30):1.

[0027] In some embodiments, in step (5), the amount of sulfuric acid added is 1 to 5% of the mass of the 2,4 / 2,5-dimethylanisole;

[0028] And / or, the amount of isobutylene introduced is 0.5 to 2 times the mass of the 2,4 / 2,5-dimethylanisole, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 15):1.

[0029] In some embodiments, in step (5), when concentrated sulfuric acid is added to the 6-tert-butyl-2,4-dimethylanisole, the amount of concentrated sulfuric acid added is 0.5 to 3%;

[0030] And / or, the reaction temperature of the stirring temperature-raising reaction is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-15):1.

[0031] The advantages and beneficial effects of the embodiments of the present invention are as follows:

[0032] (1) The method of the embodiment of the present invention uses a basic catalyst, an alkylating agent and cresol to react to obtain methylbenzyl ether homologues. The separation of some methylbenzyl ether homologues can be achieved by distillation alone, and the operation is simple;

[0033] (2) The method of the embodiment of the present invention only produces etherified products, and basically does not produce alkylation and dealkylation reactions on the benzene ring. The etherification selectivity is good, and thus distillation separation is relatively easy;

[0034] (3) The method of the embodiment of the present invention uses low-priced cresol fractions to replace refined o-cresol, pure 2,6-dimethylphenol, m-cresol, p-cresol, 2,4-dimethylphenol, etc. to produce corresponding alkyl ethers, which has low production costs and very considerable economic benefits. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0036] Where values ​​are described herein as ranges, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or sub-range is explicitly stated.

[0037] As used herein, the words "comprise," "include," and "includes" and variations thereof mean that additional elements or integers may be included although permitted but not specifically described.

[0038] In this article, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0039] The embodiment of the present invention provides a method for synthesizing anisole products using cresol fractions, comprising the following steps:

[0040] (1) adding an alkaline catalyst and a protective agent to the cresol fraction, heating and stirring, and then adding an alkylating agent to carry out an etherification reaction, and then standing and stratifying the reaction product, washing, to obtain a material layer;

[0041] (2) subjecting the material layer obtained in step (2) to a rectification treatment to obtain o-methyl anisole, a first mixed fraction (including o-methyl anisole, m-p-methyl anisole / o-ethyl anisole, 2,6-dimethyl anisole), 2,6-dimethyl anisole, a second mixed fraction (including 2,6-dimethyl anisole, 2,4 / 2,5-dimethyl anisole), 2,4 / 2,5-dimethyl anisole and a first still residue (including 2,4 / 2,5-dimethyl anisole);

[0042] (3) adding sulfuric acid to the first mixed fraction obtained in step (2), stirring and heating, and then introducing isobutylene to carry out heat preservation reaction, and then adding liquid alkali to neutralize to pH 7-8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 4-tert-butyl-2,6-dimethylanisole, the first transition fraction (including 4-tert-butyl-2,6-dimethylanisole, 4,6-di-tert-butyl-2-methylanisole, 2,6-di-tert-butyl-4-methylanisole), mixed di-tert-butylanisole (including 4,6-di-tert-butyl-2,6-dimethylanisole), and the like. tert-Butyl-2-methylanisole, 2,6-di-tert-butyl-4-methylanisole), the second transition fraction (including 4,6-di-tert-butyl-2-methylanisole, 2,6-di-tert-butyl-4-methylanisole, 4,6-di-tert-butyl-2-ethylanisole), 4,6-di-tert-butyl-2-ethylanisole, the third transition fraction (including 4,6-di-tert-butyl-2-ethylanisole, 4,6-di-tert-butyl-3-methylanisole) and the second still residue (including 4,6-di-tert-butyl-3-methylanisole);

[0043] (4) adding concentrated sulfuric acid to the 4-tert-butyl-2,6-dimethylanisole, the mixed di-tert-butylanisole, and the 4,6-di-tert-butyl-2-ethylanisole obtained in step (3), stirring and heating, and reacting them respectively. After the reaction is completed, adding alkali solution to the reaction product to neutralize it to a pH of 7 to 8, separating the layers, and subjecting the obtained material layers to vacuum distillation to obtain 2,6-dimethylanisole, o-methylanisole, p-methylanisole, o-ethylanisole, and isobutylene;

[0044] (5) adding sulfuric acid to the 2,4 / 2,5-dimethylanisole obtained in step (2), stirring and heating, then introducing isobutylene to carry out heat-insulating reaction, then adding liquid alkali to neutralize to a pH of 7-8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 6-tert-butyl-2,4-dimethylanisole, a fourth transition fraction (including 6-tert-butyl-2,4-dimethylanisole and 4-tert-butyl-2,5-dimethylanisole) and a third still residue (including 4-tert-butyl-2,5-dimethylanisole); then adding concentrated sulfuric acid to the 6-tert-butyl-2,4-dimethylanisole, stirring and heating to react, and adding alkali solution to the reaction product to neutralize to a pH of 7-8, separating the layers, and rectifying the obtained material layer under reduced pressure to obtain 2,4-dimethylanisole and isobutylene.

[0045] It should be noted that the various anisole products synthesized from the cresol fraction in the embodiment of the present invention can be further demethylated to obtain corresponding phenol products, and the specific steps are: any one of the various anisole products obtained above (such as m-methyl anisole, p-methyl anisole, 2,4-dimethyl anisole, 2,5-dimethyl anisole, 2,6-dimethyl anisole, o-ethyl anisole, etc.) is mixed with mixed trimethylbenzene, heated to 130-150° C., and then 45-55% hydrobromic acid is added dropwise to react (the addition time is 1-3 hours), and the methyl bromide gas generated by the reaction is cooled to -10° C. by a condenser and a second cold trap and enters a bromoalkane storage tank. The reaction mixture is placed in a tank (-15°C), kept warm for 1 to 4 hours after the addition is complete, and then samples are analyzed until the content of anisole products in the reaction solution is ≤0.5%, indicating that the reaction is complete. The collection of bromoalkanes is stopped, and the bromomethane generated by the reaction is collected. The reaction solution is then cooled slightly to separate the hydrobromic acid aqueous solution. The solvent layer is washed once with water and then separated into layers. The aqueous layers are combined to obtain a recovered hydrobromic acid solution (which can be sent to other sections for concentration and recovery of 47% hydrobromic acid). The trimethylbenzene is recovered in the material layer distillation kettle and reused. The material is then subjected to vacuum distillation to obtain various phenol products (such as m-cresol, p-cresol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, o-ethylphenol, etc.). This operation process is simple and easy to implement, highly practical, and has significant economic benefits, making it easy to promote and apply in industrial production.

[0046] In some embodiments, in step (1), the cresol fraction comprises 0.1-60% of o-cresol, 0.1-25% of 2,6-xylenol, 30-100% of m-cresol, 0.1-20% of 2,4 / 2,5-xylenol, and 0.1-20% of o-ethylphenol; preferably, the cresol fraction comprises 1-30% of o-cresol, 1-20% of 2,6-xylenol, 35-95% of m-cresol, 1-15% of 2,4 / 2,5-xylenol, and 1-15% of o-ethylphenol;

[0047] And / or, the alkaline catalyst includes at least one of an alkali metal and alkaline earth metal hydroxide aqueous solution (such as sodium hydroxide aqueous solution, potassium hydroxide aqueous solution), an organic amine substance (such as DBU (1,8-diazabicycloundec-7-ene), DBN (1,5-diazabicyclo[4.3.0]non-5-ene), etc.), or an alkaline substance, an alkali metal or alkaline earth metal halide and a water-insoluble metal carbonate mixture (such as potassium chloride, sodium chloride, magnesium chloride, etc. and aluminum carbonate, copper carbonate, zinc carbonate, etc.) supported on a carrier; further, when the alkaline When the catalyst is an aqueous solution of alkali metal or alkaline earth metal hydroxide, the molar ratio of phenolic substances in the cresol fraction to alkali metal or alkaline earth metal hydroxide is 1:(1-3); and when the alkaline catalyst is an organic amine or a mixture of an alkaline substance supported on a carrier, an alkali metal or alkaline earth metal halide and a water-insoluble metal carbonate, the mass ratio of phenolic substances in the cresol fraction to the organic amine or the mixture of an alkaline substance supported on a carrier, an alkali metal or alkaline earth metal halide and a water-insoluble metal carbonate is 1:(0.01-0.2);

[0048] And / or, the protective agent is at least one of the antioxidant BHT, antioxidant BHA, and 6-tert-butyl-2,4-dimethylphenol;

[0049] And / or, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, di-fatty sulfates or di-fatty carbonates.

[0050] In some embodiments, in step (1), the mass ratio of the phenolic substances in the cresol fraction to the protective agent is 1:(0.0001-0.02);

[0051] And / or, the molar ratio of the phenolic substances in the cresol fraction to the alkylating agent is 1:(0.5-5). The inventors have found through research that if the amount of the alkylating agent is too low, the phenolic materials cannot be completely etherified, and the obtained product will still contain o-cresol, 2,6-dimethylphenol, m-p-cresol / o-ethylphenol, 2,4 / 2,5-dimethylphenol, etc., and the unreacted cresols will dissolve in the ether. During distillation, since the boiling points of o-cresol are 191°C, 2,6-dimethylphenol is 203°C, and m-p-cresol is 202°C, and the boiling points of 2,4 / 2,5-dimethylanisole are 190-191°C, incomplete reaction of o-cresol will cause 2,4 / 2,5-dimethylanisole to react with methyl ether. The extraction of 5-dimethylanisole is affected (this can be avoided by controlling the content of o-cresol and 2,4 / 2,5-dimethylphenol in the cresol composition), but the overall impact is not significant, so the degree of etherification reaction can be adjusted according to the cresol composition; however, if the amount of alkylating agent is too high, although the reaction yield is guaranteed, the excess alkylating agent will dissolve in the etherified product generated by the reaction, and the small amount of alkylating agent in contact with water will gradually hydrolyze in the water, which not only causes waste of alkylating agent, but also increases the burden on wastewater treatment. Therefore, in the embodiment of the present invention, it is advantageous to control the molar ratio of phenolic substances in the cresol fraction to alkylating agent within the range of 1: (0.5-5).

[0052] In some embodiments, in step (1), the heating and stirring temperature is 30 to 80° C., and the stirring time is 0.5 to 2 h;

[0053] And / or, the reaction temperature of the etherification reaction is 0-200° C., the reaction time is 2-20 h, and the pressure required for the etherification reaction is 0-8 MPa; preferably, the reaction temperature of the etherification reaction is 40-150° C., and the pressure required for the etherification reaction is 0-1 MPa.

[0054] In some embodiments, in step (1), the static stratification is carried out at 70-90°C;

[0055] And / or, the washing includes: adding sulfuric acid solution to the material layer obtained after standing and stratifying, washing for 0.5 to 2 hours, and then washing the obtained material layer with water after stratification, and removing the washing water to obtain the material layer.

[0056] In some embodiments, in step (2), the theoretical plate of the distillation treatment is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (10 to 30):1.

[0057] In some embodiments, in step (3), the amount of sulfuric acid added is 1 to 5% of the mass of the first mixed fraction;

[0058] And / or, the amount of isobutylene introduced is 1 to 3 times the mass of the first mixed fraction, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 30):1.

[0059] In some embodiments, in step (4), the stirring and heating temperature is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-30):1.

[0060] In some embodiments, the specific process of step (4) is as follows: S1: adding concentrated sulfuric acid to the 4-tert-butyl-2,6-dimethylanisole obtained in step (3), stirring and heating to react until the content of 4-tert-butyl-2,6-dimethylanisole in the reaction product is ≤0.5%, which is qualified, indicating that the reaction is completed, and then adding alkali solution to the reaction product to neutralize it to a pH of 7 to 8, separating the layers, and subjecting the obtained material layer to vacuum distillation to obtain 2,6-dimethylanisole and isobutylene;

[0061] S2: adding concentrated sulfuric acid to the mixed di-tert-butylanisole obtained in step (3), stirring and heating to react until the content of 2-tert-butyl-4-methylanisole in the reaction product is ≤0.5% to be qualified, indicating that the reaction is complete, then adding alkali solution to the reaction product to neutralize it to a pH of 7 to 8, layering, and obtaining the material layer by vacuum distillation to obtain o-methylanisole, p-methylanisole and isobutylene;

[0062] S3: Add concentrated sulfuric acid to the 4,6-di-tert-butyl-2-ethylanisole obtained in step (3), stir and heat to react until the content of 6-tert-butyl-2-ethylanisole in the reaction product is ≤0.5%, which is qualified, indicating that the reaction is completed, and then add alkali solution to the reaction product to neutralize it to a pH of 7 to 8, separate the layers, and obtain o-ethylanisole and isobutylene after vacuum distillation.

[0063] In some embodiments, in step (5), the amount of sulfuric acid added is 1 to 5% of the mass of the 2,4 / 2,5-dimethylanisole;

[0064] And / or, the amount of isobutylene introduced is 0.5 to 2 times the mass of the 2,4 / 2,5-dimethylanisole, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 15):1.

[0065] In some embodiments, in step (5), when concentrated sulfuric acid is added to the 6-tert-butyl-2,4-dimethylanisole, the amount of concentrated sulfuric acid added is 0.5 to 3%;

[0066] And / or, the reaction temperature of the stirring temperature-raising reaction is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-15):1.

[0067] The technical solutions of the present invention are further described in detail below with reference to specific examples. Unless otherwise specified, the various raw materials used in the examples are conventional commercial products or can be prepared by known methods; and the experimental methods without specific conditions in the examples are conventional methods and conventional conditions well known in the art.

[0068] Example 1

[0069] A method for synthesizing anisole products using cresol fractions comprises the following steps:

[0070] (1) Etherification reaction

[0071] In the reactor, 6000 parts of cresol fraction (composed of o-cresol 22.91%, 2,6-dimethylphenol 15.67%, m-cresol 23%, p-cresol 15.33%, o-ethylphenol 6.08%, 2,4-dimethylphenol 9.75%, 2,5-dimethylphenol 6.92%), 360 parts of DBU (1,8-diazabicycloundecene), and 10 parts of 6-tert-butyl-2,4-dimethylphenol were added, the temperature was raised to 60°C and stirred for 1 hour, and then carbon was added. 2700 parts of dimethyl carbonate (the molar ratio of dimethyl carbonate to phenolic substances in the cresol fraction is 1.12:1), the reaction kettle is sealed, the temperature is raised to 140-150 ° C, the reaction is kept warm for 6 hours, and sampling and analysis are performed. 0.11% of m-cresol is qualified. The temperature is lowered to 80 ° C, 360 parts of water are added to the material layer, and 70 parts of sulfuric acid are added dropwise under stirring. Wash for 1 hour to remove aniline and pyridine base. The pH of the aqueous solution is 4. Layer the material layer, wash with 240 parts of water, and remove the water to obtain the material layer.

[0072] (2) Etherification distillation separation

[0073] The above material layer was added into a distillation kettle (theoretical plate was 250), and vacuum distillation was performed (-0.085 MPa), the reflux ratio was 20-25:1, and total reflux was performed for 1 hour every 3 hours of distillation. Under chromatographic analysis, 1035.6 parts of 99.59% o-methyl anisole (99.59% o-methyl anisole, 0.36% m / p-methyl anisole, and 0.05% others), 3902.8 parts of the first mixed fraction (504.6 parts of o-methyl anisole, 1540.4 parts of m-methyl anisole, 1026.8 parts of p-methyl anisole, 429.6 parts of 2,6-dimethyl anisole, and 401.4 parts of o-ethyl anisole), 605 parts of 99.57% 2,6-dimethyl anisole (0.25% m / p-methyl anisole, and 0.25% m / p-methyl anisole) were accurately collected. %, 2,6-dimethylanisole 99.57%, 2,4 / 2,5-dimethylanisole 0.15%, others 0.03%), 47.6 parts of the second mixed fraction (4.8 parts of 2,6-dimethylanisole, 25 parts of 2,4-dimethylanisole, 17.8 parts of 2,5-dimethylanisole), 1009.4 parts of 99.86% 2,4 / 2,5-dimethylanisole (0.6 part of 2,6-dimethylanisole, 589.6 parts of 2,4-dimethylanisole, 418.4 parts of 2,5-dimethylanisole, and 0.8 part of others) and 431.8 parts of the first kettle residue (including 29.8 parts of 2,4-dimethylanisole, 21.2 parts of 2,5-dimethylanisole, 21.4 parts of others and 359.4 parts of DBU).

[0074] The residue from the first kettle was used in the etherification reaction of the next batch of cresol fraction; 99.59% o-methylanisole and 99.57% 2,6-dimethylanisole were produced.

[0075] The second mixed fraction is combined in multiple batches and then distilled to obtain pure 2,6-dimethylanisole and 2,4 / 2,5-dimethylanisole.

[0076] (3) Tertiary butylation separation of the first mixed fraction

[0077] 3902.8 parts of the first mixed fraction obtained in step (2) (504.6 parts of o-methyl anisole, 1540.4 parts of m-methyl anisole, 1026.8 parts of p-methyl anisole, 429.6 parts of 2,6-dimethyl anisole, and 401.4 parts of o-ethyl anisole) and 150 parts of sulfuric acid (3.8% of the mass of the first mixed fraction) were added to the reactor. The temperature was raised to 90° C. under stirring, and then 5000 parts of isobutylene (1.28 times the mass of the first mixed fraction) was introduced to react. The isobutylene was introduced for 7.5 hours, and the reaction was kept warm for 2.0 hours after the isobutylene was introduced. Sampling and analysis of 6-tert-butyl-3-methyl Anisole 0.15% is qualified, and 1305 parts of isobutylene are recovered and applied; then 389 parts of 31% liquid alkali are added to neutralize to a pH of 7.5, the water layer is separated, and the material layer is added to a high-efficiency distillation tower (theoretical plate is 250, pressure is -0.095MPa, reflux ratio is 20-25:1) for distillation to obtain 258 parts of diisobutylene, 560.5 parts of 99.51% 4-tert-butyl-2,6-dimethylanisole, 228.9 parts of the first transition fraction (42 parts of 4-tert-butyl-2,6-dimethylanisole, 63.8 parts of 4,6-di-tert-butyl-2-methylanisole, 2,6-di-tert-butyl-4-methylanisole). 123.1 parts of methyl ether), 2612 parts of 99.79% mixed di-tert-butylanisole (0.05% of 4-tert-butyl-2,6-dimethylanisole, 32.78% of 4,6-di-tert-butyl-2-methylanisole, 67.01% of 2,6-di-tert-butyl-4-methylanisole, and 0.16% of 4,6-di-tert-butyl-2-ethylanisole), 197.9 parts of the second transition fraction (35.2 parts of 4,6-di-tert-butyl-2-methylanisole, 72.6 parts of 2,6-di-tert-butyl-4-methylanisole, and 90.1 parts of 4,6-di-tert-butyl-2-ethylanisole), 99.83 % 4,6-di-tert-butyl-2-ethylanisole 584.4 parts (4,6-di-tert-butyl-2-methylanisole 0.2 parts, 2,6-di-tert-butyl-4-methylanisole 0.4 parts, 4,6-di-tert-butyl-2-ethylanisole 583.4 parts, 4,6-di-tert-butyl-3-methylanisole 0.4 parts), 172.2 parts of the third transition fraction (47.9 parts of 4,6-di-tert-butyl-2-ethylanisole, 124.3 parts of 4,6-di-tert-butyl-3-methylanisole) and 2804.2 parts of the second kettle residue (2800.4 parts of 4,6-di-tert-butyl-3-methylanisole).

[0078] The first transition fraction is re-distilled to obtain 99% 4-tert-butyl-2,6-dimethylanisole, a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole; the second transition fraction is re-distilled to obtain a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole, and 99% 4,6-di-tert-butyl-2-ethylanisole; the third transition fraction is re-distilled to obtain 99% 4,6-di-tert-butyl-2-ethylanisole, leaving a distillation pot residue (4,6-di-tert-butyl-3-methylanisole).

[0079] (4) Deisobutylene and distillation of tert-butyl compounds

[0080] S1: To 560.5 parts of 98% concentrated sulfuric acid (1.6% of the mass of 4-tert-butyl-2,6-dimethylanisole) obtained in step (3) were added 9 parts of 98% concentrated sulfuric acid (1.6% of the mass of 4-tert-butyl-2,6-dimethylanisole), stirring was started, and the temperature was raised to 190°C for reaction. After reacting for 2.5 hours, sampling and analysis showed that the content of 4-tert-butyl-2,6-dimethylanisole was qualified at 0.11%. Then, 23.4 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The reaction was separated into layers and the material layer was subjected to vacuum distillation (theoretical plate was 200, pressure was -0.080 MPa, and reflux ratio was 10:1) to obtain 369.4 parts of 99.8% 2,6-dimethylanisole in sequence, with a yield of 93.5%. 159 parts of isobutylene were recovered for use.

[0081] S2: To 2612 parts of 99.79% mixed di-tert-butylanisole (0.05% of 4-tert-butyl-2,6-dimethylanisole, 32.78% of 4,6-di-tert-butyl-2-methylanisole, 67.01% of 2,6-di-tert-butyl-4-methylanisole, and 0.16% of 4,6-di-tert-butyl-2-ethylanisole) obtained in step (3), 46 parts of 98% concentrated sulfuric acid (1.76% of the mass of the mixed di-tert-butylphenol) were added, stirring was started, the temperature was raised to 185°C for reaction, and after reaction for 3 hours, sampling and analysis were performed. 2-tert-butyl- 4-Methylanisole content 0.16% is qualified, and in reaction product, adding 119.6 parts of 31% alkali lyes to be neutralized to pH is 8 again, layering, material bed rectification under vacuum (theoretical plate is 200, pressure is-0.080MPa, reflux ratio are 25:1) obtains 370 parts of 99.62% o-methylanisole, 234.8 parts of middle distillates (72.6 parts of o-methylanisole, 161.9 parts of p-methylanisole, other 0.3 part), 742.1 parts of 99.72% p-methylanisole successively, reclaim 1224.3 parts of iso-butylenes and apply mechanically.

[0082] S3: To 584.4 parts of 99.83% 4,6-di-tert-butyl-2-ethylanisole (0.2 parts of 4,6-di-tert-butyl-2-methylanisole, 0.4 parts of 2,6-di-tert-butyl-4-methylanisole, 583.4 parts of 4,6-di-tert-butyl-2-ethylanisole, and 0.4 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3) was added 12 parts of 98% concentrated sulfuric acid (2.05 parts of the mass of 4,6-di-tert-butyl-2-ethylanisole). %), start stirring, heat to 190 ℃ and react, after reacting for 2 hours, take samples and analyze, 6-tert-butyl-2-ethylanisole content 0.19% is qualified, then add 31 parts of 31% alkali solution to the reaction product and neutralize it to pH 7.5, layer and separate, the material layer is distilled under reduced pressure (theoretical plate is 200, pressure is -0.080MPa, reflux ratio is 5:1) to obtain 390.8 parts of 99.75% o-ethylanisole, the yield is 94.5%, and 166.2 parts of isobutylene are recovered for use.

[0083] S4: To 2804.2 parts of the second kettle residue (2800.4 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3), 71 parts of 98% concentrated sulfuric acid (2.53% of the mass of the kettle residue) were added, stirring was started, and the temperature was raised to 200°C for reaction. After reacting for 1.5 hours, sampling and analysis were performed. The 6-tert-butyl-3-methylanisole content was 0.12%, which was qualified. Then, 183.2 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The mixture was separated and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure of -0.080 MPa, reflux ratio of 10:1) to obtain 1382.1 parts of 99.87% m-methylanisole with a yield of 93.9%, and 1310 parts of isobutylene were recovered for use.

[0084] The distillation still residue in step (3) is subjected to deisobutylene, neutralization and distillation according to the method of the second still residue to obtain ≥99% of m-methyl anisole.

[0085] (5) Separation of 2,4 / 2,5-dimethylanisole

[0086] 1009.4 parts of 99.86% 2,4 / 2,5-dimethylanisole (0.6 parts of 2,6-dimethylanisole, 589.6 parts of 2,4-dimethylanisole, 418.4 parts of 2,5-dimethylanisole and 0.8 parts of others) and 16 parts of 98% sulfuric acid (1.58% of the mass of 2,4 / 2,5-dimethylanisole) obtained in step (2) were added to the reactor. After heating to 110° C. with stirring, 1180 parts of isobutylene (1.17 times the mass of 2,4 / 2,5-dimethylanisole) were introduced to react. The isobutylene was introduced for 5 hours. After the reaction was kept warm for 2.5 hours, sampling and analysis showed that 2,4-dimethylanisole had a high yield. Methyl anisole 0.24% is qualified, - then 41.5 parts of 31% liquid caustic soda is added to neutralize to pH 7.5, the water layer is divided, and the material layer is added into a high-efficiency distillation tower (theoretical plate 200, pressure -0.090MPa), and distilled at a reflux ratio of 15 to 20:1 to obtain 94.5 parts of diisobutylene, 99.77% 6-tert-butyl-2, 4-dimethylanisole 786 parts, 67 parts of the fourth transition fraction (6-tert-butyl-2, 4-dimethylanisole 38.6 parts, 4-tert-butyl-2, 5-dimethylanisole 28.4 parts), and 557.4 parts of the third kettle residue (555.6 parts of 4-tert-butyl-2, 5-dimethylanisole).

[0087] Subsequently, 16 parts of 98% concentrated sulfuric acid (2.04% of the mass of 6-tert-butyl-2,4-dimethylanisole) were added to 786 parts of 99.77% 6-tert-butyl-2,4-dimethylanisole, the stirring was started, the temperature was raised to 195°C for reaction, and the reaction was sampled and analyzed after 2 hours. The content of 4-tert-butyl-2,4-dimethylanisole was qualified at 0.18%. Then, 41.5 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5, the layers were separated, and the material layer was vacuum distilled (theoretical plate 200, pressure -0.085 MPa, reflux ratio 5: 1) to obtain 530.9 parts of 99.7% 2,4-dimethylanisole and 223.9 parts of isobutylene were recovered for application.

[0088] The fourth transition fraction is re-distilled to obtain ≥99% of 6-tert-butyl-2,4-dimethylanisole.

[0089] To the third still residue 557.4 parts (4-tert-butyl-2,5-dimethylanisole 555.6 parts) were added 12 parts of 98% concentrated sulfuric acid (2.15% by mass of 4-tert-butyl-2,5-dimethylanisole), stirring was started, the reaction was warmed to 190°C, and after 2 hours of reaction, sampling and analysis, 4-tert-butyl-2,5-dimethylanisole content 0.33% was qualified, and then 31 parts of 31% alkali liquor were added to the reaction product to neutralize it to a pH of 7.5, layered, and the material layer was distilled under reduced pressure (theoretical plate 200, pressure-0.085 MPa, reflux ratio 8: 1) to obtain 99.75% 2,5-dimethylanisole 374.3 parts successively, and 157.5 parts of isobutylene were recovered and used mechanically.

[0090] (6) Synthesis of 2,5-dimethylphenol and 2,6-dimethylphenol

[0091] Add 374.3 parts of 99.75% 2,5-dimethylanisole and 600 parts of mixed trimethylbenzene in step (5) to the reactor, heat to 130-140°C, add 47% hydrobromic acid dropwise to react, and the bromomethane gas generated by the reaction is cooled to -10°C through a condenser and a second cold trap and enters a bromoalkane storage tank (-15°C). After the reaction is completed, stop collecting bromoalkanes, add 824 parts of 47% hydrobromic acid dropwise, collect 250.6 parts of bromomethane, and the yield is 96%. .1%; the reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 24 parts of water, the layers were separated, and the water layers were combined to obtain 596.4 parts of 26.7% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), and 587 parts of trimethylbenzene were recovered from the material layer distillation kettle and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 5:1) to obtain 311.1 parts of pharmaceutical grade 99.93% 2,5-dimethylphenol, with a yield of 92.8%.

[0092] The reactor was added with 300 parts of 99.8% 2,6-dimethylanisole and 500 parts of mixed trimethylbenzene obtained in step (4) S1, and the temperature was raised to 130-140°C. 47% hydrobromic acid was added dropwise to react. The bromomethane gas generated by the reaction was cooled to -10°C by a condenser and a second cold trap and entered the bromoalkane storage tank (-15°C). After the reaction was completed, the collection of bromoalkanes was stopped. A total of 660 parts of 47% hydrobromic acid were added dropwise, and 203 parts of bromomethane were collected. The yield was 97%. .1%; the reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 20 parts of water, the layers were separated, and the water layers were combined to obtain 479.8 parts of 26.6% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), and 496 parts of trimethylbenzene were recovered from the material layer distillation kettle and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 5:1) to obtain 252 parts of polymerization grade 99.85% 2,6-dimethylphenol, with a yield of 93.7%.

[0093] Example 2

[0094] A method for synthesizing anisole products using cresol fractions comprises the following steps:

[0095] (1) Etherification reaction

[0096] In an enameled reactor, 3820 parts of cresol fraction (composed of 22.91% o-cresol, 15.67% 2,6-xylenol, 23% m-cresol, 15.33% p-cresol, 6.08% o-ethylphenol, 9.75% 2,4-xylenol, and 6.92% 2,5-xylenol) and 7774 parts of a 20% sodium hydroxide aqueous solution (the molar ratio of cresol to sodium hydroxide is 1:1.15) were added, stirred, heated to 60°C, and stirred for 1 hour to obtain 11594 parts of a cresol sodium salt aqueous solution; BHT was then added. 3 parts, and 3100 parts of dimethyl carbonate (the molar ratio of dimethyl carbonate to phenolic substances in the cresol fraction is 1.01: 1) are added dropwise, the temperature is raised to 80°C, the addition time is 5 hours, and after the addition is completed, the mixture is kept warm at 95-100°C for 5 hours for sampling and analysis, and 0.09% of meta-cresol is qualified. The mixture is cooled to 80°C and allowed to stand for stratification, and the lower aqueous layer is separated and sent to the wastewater station. 225 parts of water are added to the material layer while stirring, and 45 parts of sulfuric acid are added dropwise for washing for 1 hour to remove aniline and pyridine base. The pH of the aqueous solution is 4, and the layers are separated. 150 parts of the material layer are washed with water, and the water is completely separated to obtain the material layer.

[0097] (2) Etherification distillation separation

[0098] The above material layer was added into a distillation kettle (theoretical plate 250), and vacuum distillation was performed (-0.085 MPa) with a reflux ratio of 20 to 25:1. The total reflux was performed for 1 hour after every 3 hours of distillation. Under chromatographic analysis, 659.4 parts of 99.68% o-methyl anisole (99.68% o-methyl anisole, 0.30% m / p-methyl anisole, and 0.02% others), 2485 parts of the first mixed fraction (321.3 parts of o-methyl anisole, 980.8 parts of m-methyl anisole, 653.7 parts of p-methyl anisole, 273.6 parts of 2,6-dimethyl anisole, and 255.6 parts of o-ethyl anisole) and 385.2 parts of 99.49% 2,6-dimethyl anisole (0.27% m / p-methyl anisole) were accurately collected. %, 2,6-dimethylanisole 99.53%, 2,4 / 2,5-dimethylanisole 0.19%, others 0.01%), 30.4 parts of the second mixed fraction (3.1 parts of 2,6-dimethylanisole, 15.9 parts of 2,4-dimethylanisole, 11.4 parts of 2,5-dimethylanisole), 642.6 parts of 99.88% 2,4 / 2,5-dimethylanisole (0.3 part of 2,6-dimethylanisole, 375.4 parts of 2,4-dimethylanisole, 266.4 parts of 2,5-dimethylanisole, others 0.5 part) and 46.2 parts of the first kettle residue (including 19 parts of 2,4-dimethylanisole, 13.5 parts of 2,5-dimethylanisole and 13.7 parts of others).

[0099] The first batch of residues were combined and distilled to obtain 2,4 / 2,5-dimethylanisole; 99.68% o-methylanisole and 99.49% 2,6-dimethylanisole products were taken out.

[0100] The second mixed fraction is combined in multiple batches and then distilled to obtain pure 2,6-dimethylanisole and 2,4 / 2,5-dimethylanisole.

[0101] (3) Tertiary butylation separation of the first mixed fraction

[0102] 2485 parts of the first mixed fraction (321.3 parts of o-methyl anisole, 980.8 parts of m-methyl anisole, 653.7 parts of p-methyl anisole, 273.6 parts of 2,6-dimethyl anisole, and 255.6 parts of o-ethyl anisole) obtained in step (2) and 75 parts of sulfuric acid (3% of the mass of the first mixed fraction) were added to the reactor. After heating to 75° C. with stirring, 3150 parts of isobutylene (1.27 times the mass of the first mixed fraction) were introduced to react. The isobutylene was introduced for 7.5 hours, and the reaction was kept warm for 2 hours. Sampling and analysis showed that 0.19% of 6-tert-butyl-3-methyl anisole was obtained. The product was qualified, and 800.9 parts of isobutylene were recovered and applied; then 194.5 parts of 31% liquid alkali were added to neutralize it to a pH of 7.5, the water layer was separated, and the material layer was added to a high-efficiency distillation tower (theoretical plate 250, pressure -0.095MPa), and distilled at a reflux ratio of 20 to 25:1 to obtain 165 parts of diisobutylene, 357.6 parts of 99.33% 4-tert-butyl-2,6-dimethylanisole, and 145.8 parts of the first transition fraction (26.8 parts of 4-tert-butyl-2,6-dimethylanisole, 40.7 parts of 4,6-di-tert-butyl-2-methylanisole, and 2,6-di-tert-butyl-4-methylanisole). 78.3 parts), 99.86% mixed di-tert-butylanisole 1662.3 parts (4-tert-butyl-2,6-dimethylanisole 0.02%, 4,6-di-tert-butyl-2-methylanisole 32.81%, 2,6-di-tert-butyl-4-methylanisole 67.05%, 4,6-di-tert-butyl-2-ethylanisole 0.12%), 126 parts of the second transition fraction (4,6-di-tert-butyl-2-methylanisole 22.5 parts, 2,6-di-tert-butyl-4-methylanisole 46.2 parts, 4,6-di-tert-butyl-2-ethylanisole 57.3 parts), 99.81% 372.5 parts of 4,6-di-tert-butyl-2-ethylanisole (0.1 part of 4,6-di-tert-butyl-2-methylanisole, 0.3 part of 2,6-di-tert-butyl-4-methylanisole, 371.8 parts of 4,6-di-tert-butyl-2-ethylanisole, 0.3 part of 4,6-di-tert-butyl-3-methylanisole), 109.7 parts of the third transition fraction (30.6 parts of 4,6-di-tert-butyl-2-ethylanisole, 79.1 parts of 4,6-di-tert-butyl-3-methylanisole) and 1785.3 parts of the second still residue (1782.9 parts of 4,6-di-tert-butyl-3-methylanisole).

[0103] The first transition fraction is re-distilled to obtain 99% 4-tert-butyl-2,6-dimethylanisole, a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole; the second transition fraction is re-distilled to obtain a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole, and 99% 4,6-di-tert-butyl-2-ethylanisole; the third transition fraction is re-distilled to obtain 99% 4,6-di-tert-butyl-2-ethylanisole, leaving a distillation pot residue (4,6-di-tert-butyl-3-methylanisole).

[0104] (4) Deisobutylene and distillation of tert-butyl compounds

[0105] S1: 4.5 parts of 98% concentrated sulfuric acid (1.26% of the mass of 4-tert-butyl-2,6-dimethylanisole) were added to 357.6 parts of 99.33% 4-tert-butyl-2,6-dimethylanisole obtained in step (3), and the mixture was stirred and heated to 195°C for reaction. After reacting for 2 hours, sampling and analysis showed that the 4-tert-butyl-2,6-dimethylanisole content was 0.21%, which was qualified. 11.7 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5, and the mixture was separated into layers. The material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 8:1) to obtain 236.9 parts of 99.6% 2,6-dimethylanisole in sequence, with a yield of 93.8%, and 101.3 parts of isobutylene were recovered for use.

[0106] S2: To 1662.3 parts of 99.86% mixed di-tert-butylanisole (0.3 parts of 4-tert-butyl-2,6-dimethylanisole, 545.4 parts of 4,6-di-tert-butyl-2-methylanisole, 1115.1 parts of 2,6-di-tert-butyl-4-methylanisole, and 1.5 parts of 4,6-di-tert-butyl-2-ethylanisole) obtained in step (3), 23 parts of 98% concentrated sulfuric acid (1.38% of the mass of the mixed di-tert-butylphenol) were added, stirring was started, the temperature was raised to 185°C, and the reaction was carried out for 3 hours. Samples were taken for analysis, and 2-tert-butylanisole was obtained. The reaction mixture was stirred for 2 hours, and the reaction mixture was stirred for 1 hour.Then the reaction mixture was stirred for 2 hours.The reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 1 hour.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 1 hour.Then the reaction mixture was stirred for 2 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.

[0107] S3: To 372.5 parts of 99.81% 4,6-di-tert-butyl-2-ethylanisole (0.1 parts of 4,6-di-tert-butyl-2-methylanisole, 0.3 parts of 2,6-di-tert-butyl-4-methylanisole, 371.8 parts of 4,6-di-tert-butyl-2-ethylanisole, and 0.3 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3) were added 7.5 parts of 98% concentrated sulfuric acid (2.0 parts of the mass of 4,6-di-tert-butyl-2-ethylanisole). 01%), start stirring, heat to 190 ° C for reaction, react for 2 hours, take samples for analysis, 6-tert-butyl-2-ethylanisole content 0.25% qualified, then add 31% alkali solution 19.5 parts to the reaction product to neutralize to pH 7.5, separate layers, and conduct vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 5: 1) of the material layer to obtain 99.75% o-ethylanisole 249.8 parts, a yield of 94.6%, and recover 106 parts of isobutylene for use.

[0108] S4: To 1785.3 parts of the second kettle residue (1782.9 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3), 45 parts of 98% concentrated sulfuric acid (2.52% of the mass of the kettle residue) were added, stirring was started, and the temperature was raised to 200°C for reaction. After 1.2 hours of reaction, sampling and analysis showed that the 6-tert-butyl-3-methylanisole content was 0.33%, which was qualified. Then, 120.3 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The mixture was separated and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 10:1) to obtain 882 parts of 99.79% m-methylanisole with a yield of 93.9%, and 834 parts of isobutylene were recovered for use.

[0109] The distillation still residue in step (3) is subjected to deisobutylene, neutralization and distillation according to the method of the second still residue to obtain ≥99% of m-methyl anisole.

[0110] (5) Separation of 2,4 / 2,5-dimethylanisole

[0111] 642.6 parts of 99.88% 2,4 / 2,5-dimethylanisole (0.3 parts of 2,6-dimethylanisole, 375.4 parts of 2,4-dimethylanisole, 266.4 parts of 2,5-dimethylanisole, and 0.5 parts of others) and 10.5 parts of 98% sulfuric acid (1.63% of the mass of 2,4 / 2,5-dimethylanisole) obtained in step (2) were added to the reactor. After heating to 110° C. with stirring, 750 parts of isobutylene (1.16 times the mass of 2,4 / 2,5-dimethylanisole) were introduced to react. The isobutylene was introduced for 5 hours. After the reaction was kept warm for 2 hours, sampling and analysis were performed. 0.34% of methyl ether was qualified, and then 27.2 parts of 31% liquid caustic soda was added to neutralize it to a pH of 7.5. The water layer was separated and the material layer was added to a high-efficiency distillation tower (theoretical plate 200, pressure -0.090 MPa), and distilled at a reflux ratio of 10 to 15:1 to obtain 60.3 parts of diisobutylene, 500.7 parts of 99.77% 6-tert-butyl-2,4-dimethylanisole, 42.7 parts of the fourth transition fraction (24.6 parts of 6-tert-butyl-2,4-dimethylanisole, 18.1 parts of 4-tert-butyl-2,5-dimethylanisole), and 354.9 parts of the third kettle residue (353.8 parts of 4-tert-butyl-2,5-dimethylanisole).

[0112] Subsequently, 10.5 parts of 98% concentrated sulfuric acid (2.1% of the mass of 6-tert-butyl-2,4-dimethylanisole) were added to 500.7 parts of 99.77% 6-tert-butyl-2,4-dimethylanisole, stirring was started, the temperature was raised to 190°C for reaction, and sampling and analysis were performed after 2 hours of reaction. The content of 4-tert-butyl-2,4-dimethylanisole was qualified at 0.31%. 27.2 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5, and the layers were separated. The material layer was vacuum distilled (theoretical plate 200, pressure -0.085 MPa, reflux ratio 5: 1) to obtain 337.4 parts of 99.9% 2,4-dimethylanisole and 142.7 parts of isobutylene were recovered for application.

[0113] The fourth transition fraction is re-distilled to obtain ≥99% of 6-tert-butyl-2,4-dimethylanisole.

[0114] To the third still residue 354.9 parts (4-tert-butyl-2,5-dimethylanisole 353.8 parts) were added 7.5 parts of 98% concentrated sulfuric acid (2.11% by mass of 4-tert-butyl-2,5-dimethylanisole), stirring was started, the reaction was warmed to 180°C, and after 2.5 hours of reaction, sampling and analysis, 4-tert-butyl-2,5-dimethylanisole content 0.45% qualified, and then 19.5 parts of 31% alkali liquor were added to the reaction product to neutralize it to a pH of 7.5, layered, and the material layer was distilled under reduced pressure (theoretical plate 200, pressure-0.085 MPa, reflux ratio 10: 1) to obtain 99.83% 2,5-dimethylanisole 238.2 parts successively, and 100.5 parts of isobutylene were recovered and used mechanically.

[0115] (6) Synthesis of 2,5-dimethylphenol and o-ethylphenol

[0116] Add 238.2 parts of 99.83% 2,5-dimethylanisole and 300 parts of mixed trimethylbenzene in step (5) to the reactor, heat to 130-140°C, add 47% hydrobromic acid dropwise to react, and the bromomethane gas generated by the reaction is cooled to -10°C through a condenser and two cold traps and enters a bromoalkane storage tank (-15°C). After the reaction is completed, stop collecting bromoalkanes, add 525 parts of 47% hydrobromic acid dropwise, collect 161.2 parts of bromomethane, and the yield is 0.05. 97.1%; then the reaction solution was cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 15 parts of water, the layers were separated, and the water layers were combined to obtain 379.8 parts of 26.8% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), 294 parts of trimethylbenzene were recovered in the material layer distillation kettle and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 10:1) to obtain 200.7 parts of 99.95% 2,5-xylenol, with a yield of 94%.

[0117] The reactor was added with 249.8 parts of 99.75% o-ethylanisole and 300 parts of mixed trimethylbenzene in step (4), and the temperature was raised to 130-140°C. 47% hydrobromic acid was added dropwise to react. The bromomethane gas generated by the reaction was cooled to -10°C by a condenser and two cold traps and then entered into a bromoalkane storage tank (-15°C). After the reaction was completed, the collection of bromoalkanes was stopped. A total of 550 parts of 47% hydrobromic acid was added dropwise and 169 parts of bromomethane were collected. The yield was 96. 5%; the reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 12 parts of water, the layers were separated, and the water layers were combined to obtain 391 parts of 27.3% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), 295 parts of trimethylbenzene were recovered from the material layer distillation kettle and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 10:1) to obtain 208.3 parts of 99.92% o-ethylphenol, with a yield of 93.1%.

[0118] Example 3

[0119] A method for synthesizing anisole products using cresol fractions comprises the following steps:

[0120] (1) Etherification reaction

[0121] 5000 parts of cresol fraction (composed of 22.91% o-cresol, 15.67% 2,6-xylenol, 23% m-cresol, 15.33% p-cresol, 6.08% o-ethylphenol, 9.75% 2,4-xylenol, 6.92% 2,5-xylenol) and 13090 parts of 20% sodium hydroxide aqueous solution (the molar ratio of cresol to sodium hydroxide is 1:1.54) were added to an enameled reactor, stirred, heated to 60°C and stirred for 1 hour to obtain 18074 parts of cresol sodium salt aqueous solution; then 3 parts of BHA were added. 5800 parts of dimethyl sulfate (the molar ratio of dimethyl sulfate to phenolic substances in the cresol fraction is 1.03:1) are added dropwise, the temperature is controlled at 40°C, the addition time is 5 hours, the temperature is raised to 90-95°C and the reaction is kept warm for 10 hours, sampling and analysis show that 0.13% of m-cresol is qualified, the temperature is lowered to 80°C and allowed to stand for stratification, the lower aqueous layer is separated, the aqueous layer is sent to the wastewater station, 300 parts of water are added to the material layer, 50 parts of sulfuric acid are added dropwise while stirring, and washed for 1 hour to remove aniline and pyridine base. The pH of the aqueous solution is 4, the layers are separated, and the material layer is washed with 200 parts of water. The water is separated to obtain the material layer.

[0122] (2) Etherification distillation separation

[0123] The above material layer was added to a distillation kettle (theoretical plate 250), and vacuum distillation was performed (-0.085 MPa) at a reflux ratio of 20 to 25:1. The total reflux was performed for 1 hour after every 3 hours of distillation. Under chromatographic analysis, 863.1 parts of 99.69% o-methyl anisole (99.69% o-methyl anisole, 0.29% m- / p-methyl anisole, and 0.02% others), 3252.9 parts of the first mixed fraction (420.6 parts o-methyl anisole, 1283.9 parts m-methyl anisole, 855.7 parts p-methyl anisole, 358.1 parts 2,6-dimethyl anisole, and 334.6 parts o-ethyl anisole) and 465.5 parts of 99.52% 2,6-dimethyl anisole (0. 27%, 2,6-dimethylanisole 99.53%, 2,4 / 2,5-dimethylanisole 0.19%, others 0.01%), 39.7 parts of the second mixed fraction (4 parts of 2,6-dimethylanisole, 20.8 parts of 2,4-dimethylanisole, 14.9 parts of 2,5-dimethylanisole), 841.1 parts of 99.88% 2,4 / 2,5-dimethylanisole (0.4 part of 2,6-dimethylanisole, 491.4 parts of 2,4-dimethylanisole, 348.7 parts of 2,5-dimethylanisole, and 0.6 part of others) and 60.4 parts of the first kettle residue (including 24.8 parts of 2,4-dimethylanisole, 17.7 parts of 2,5-dimethylanisole and 17.9 parts of others).

[0124] The first batch of residues were combined and distilled to obtain 2,4 / 2,5-dimethylanisole; 99.69% o-methylanisole and 99.52% 2,6-dimethylanisole products were sold out.

[0125] The second mixed fraction is combined in multiple batches and then distilled to obtain pure 2,6-dimethylanisole and 2,4 / 2,5-dimethylanisole.

[0126] (3) Tertiary butylation separation of the first mixed fraction

[0127] 3252.9 parts of the first mixed fraction (420.6 parts of o-methyl anisole, 1283.9 parts of m-methyl anisole, 855.7 parts of p-methyl anisole, 358.1 parts of 2,6-dimethyl anisole, 334.6 parts of o-ethyl anisole) obtained in step (2) and 98.2 parts of sulfuric acid (3% of the mass of the first mixed fraction) were added to the reactor, and the temperature was raised to 75° C. under stirring, and then 4123 parts of isobutylene (1.27 times the mass of the first mixed fraction) was introduced to react. The isobutylene was introduced for 7 hours, and the reaction was kept warm for 2.5 hours. Sampling and analysis of 6-tert-butyl-3-methyl anisole were performed. .15% qualified, 1048.3 parts of isobutylene were recovered and used; then 254.1 parts of 31% liquid alkali were added to neutralize to pH 7.5, the water layer was separated, and the material layer was added to a high-efficiency distillation tower (theoretical plate 250, pressure -0.090MPa), and distilled at a reflux ratio of 20 to 25:1 to obtain 215.8 parts of diisobutylene, 468 parts of 99.35% 4-tert-butyl-2,6-dimethylanisole, 190.8 parts of the first transition fraction (35.1 parts of 4-tert-butyl-2,6-dimethylanisole, 53.3 parts of 4,6-di-tert-butyl-2-methylanisole, 2,6-di-tert-butyl-4-methylanisole, 104.1 parts of 31% liquid alkali, and 104.1 parts of 31% liquid alkali. anisole 102.4 parts), 99.84% mixed di-tert-butyl anisole 2175.9 parts (4-tert-butyl-2,6-dimethylanisole 0.02%, 4,6-di-tert-butyl-2-methylanisole 32.8%, 2,6-di-tert-butyl-4-methylanisole 67.04%, 4,6-di-tert-butyl-2-ethylanisole 0.14%), 164.9 parts of the second transition fraction (4,6-di-tert-butyl-2-methylanisole 29.4 parts, 2,6-di-tert-butyl-4-methylanisole 60.5 parts, 4,6-di-tert-butyl-2-ethylanisole 75 parts), 99.83 % 4,6-di-tert-butyl-2-ethylanisole 487.6 parts (4,6-di-tert-butyl-2-methylanisole 0.1 part, 2,6-di-tert-butyl-4-methylanisole 0.4 part, 4,6-di-tert-butyl-2-ethylanisole 486.7 parts, 4,6-di-tert-butyl-3-methylanisole 0.4 part), 143.6 parts of the third transition fraction (40.1 parts of 4,6-di-tert-butyl-2-ethylanisole, 103.5 parts of 4,6-di-tert-butyl-3-methylanisole) and 2336.9 parts of the second kettle residue (2333.8 parts of 4,6-di-tert-butyl-3-methylanisole).

[0128] The first transition fraction is re-distilled to obtain 99% 4-tert-butyl-2,6-dimethylanisole, a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole; the second transition fraction is re-distilled to obtain a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole, and 99% 4,6-di-tert-butyl-2-ethylanisole; the third transition fraction is re-distilled to obtain 99% 4,6-di-tert-butyl-2-ethylanisole, leaving a distillation pot residue (4,6-di-tert-butyl-3-methylanisole).

[0129] (4) Deisobutylene and distillation of tert-butyl compounds

[0130] S1: To 468 parts of 99.35% 4-tert-butyl-2,6-dimethylanisole obtained in step (3), 5.9 parts of 98% concentrated sulfuric acid (1.26% of the mass of 4-tert-butyl-2,6-dimethylanisole) were added, stirring was started, and the temperature was raised to 195°C for reaction. After reacting for 2 hours, sampling and analysis were performed, and the 4-tert-butyl-2,6-dimethylanisole content was 0.18%, which was qualified. Then, 15.3 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The reaction was separated into layers, and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 9:1) to obtain 307.5 parts of 99.7% 2,6-dimethylanisole in sequence, with a yield of 93.1%, and 132.5 parts of isobutylene were recovered for use.

[0131] S2: To 2175.9 parts of 99.84% mixed di-tert-butylanisole (0.02% of 4-tert-butyl-2,6-dimethylanisole, 32.8% of 4,6-di-tert-butyl-2-methylanisole, 67.04% of 2,6-di-tert-butyl-4-methylanisole, and 0.14% of 4,6-di-tert-butyl-2-ethylanisole) obtained in step (3) were added 30 parts of 98% concentrated sulfuric acid (1.38% of the mass of the mixed di-tert-butylphenol), stirring was started, the temperature was raised to 185°C, and the reaction was carried out for 3 hours. Samples were taken for analysis, and 2-tert-butylanisole was obtained. The reaction mixture was stirred for 2 hours, and the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 2 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 4 hours.Then the reaction mixture was stirred for 5 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 3 hours.Then the reaction mixture was stirred for 4 hours.

[0132] S3: To 487.6 parts of 98% concentrated sulfuric acid (2.01% of the mass of 4,6-di-tert-butyl-2-ethylanisole) obtained in step (3), 9.8 parts of 98% concentrated sulfuric acid were added (the mass of 4,6-di-tert-butyl-2-ethylanisole was 2.01%), stirring was started, and the temperature was raised to 195°C for reaction. After reacting for 2 hours, sampling and analysis showed that the 6-tert-butyl-2-ethylanisole content was 0.08%, which was qualified. Then 25.3 parts of 31% alkali liquor were added to the reaction product to neutralize it to a pH of 7.5. The reaction was separated into layers, and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 5:1) to obtain 253.5 parts of 99.82% o-ethylanisole with a yield of 94.8%. 138.5 parts of isobutylene were recovered for use.

[0133] S4: To 2336.9 parts of the second kettle residue (2333.8 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3) were added 59 parts of 98% concentrated sulfuric acid (2.52% of the mass of the kettle residue), stirring was started, and the temperature was raised to 200°C for reaction. After reaction for 1.2 hours, sampling and analysis were performed. The 6-tert-butyl-3-methylanisole content was 0.29%, which was qualified. Then, 152.3 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The mixture was separated and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 10:1) to obtain 1136.8 parts of 99.86% m-methylanisole with a yield of 93.3%. 1091.3 parts of isobutylene were recovered for use.

[0134] The distillation still residue in step (3) is subjected to deisobutylene, neutralization and distillation according to the method of the second still residue to obtain ≥99% of m-methyl anisole.

[0135] (5) Separation of 2,4 / 2,5-dimethylanisole

[0136] 841.1 parts of 99.88% 2,4 / 2,5-dimethylanisole (0.4 parts of 2,6-dimethylanisole, 491.4 parts of 2,4-dimethylanisole, 348.7 parts of 2,5-dimethylanisole, and 0.6 parts of others) and 13.7 parts of 98% sulfuric acid (1.63% of the mass of 2,4 / 2,5-dimethylanisole) obtained in step (2) were added to the reactor. After heating to 110° C. with stirring, 980 parts of isobutylene (1.16 times the mass of 2,4 / 2,5-dimethylanisole) were introduced to react. The isobutylene was introduced for 6 hours. After the reaction was kept warm for 2 hours, sampling and analysis showed that 2,4-dimethylanisole 0.31% of anisole is qualified, and then 35.4 parts of 31% liquid caustic soda is added to neutralize it to a pH of 7.5, the water layer is divided, and the material layer is added into a high-efficiency distillation tower (theoretical plate 200, pressure-0.090MP), and distilled at a reflux ratio of 10 to 15:1 to obtain 78.9 parts of diisobutylene, 99.72% of 6-tert-butyl-2, 4-dimethylanisole 655.7 parts, 55.9 parts of the fourth transition fraction (32.2 parts of 6-tert-butyl-2, 4-dimethylanisole, 23.7 parts of 4-tert-butyl-2, 5-dimethylanisole), and 464.5 parts of the third kettle residue (463.1 parts of 4-tert-butyl-2, 5-dimethylanisole).

[0137] Subsequently, 13.7 parts of 98% concentrated sulfuric acid (2.09% of the mass of 6-tert-butyl-2,4-dimethylanisole) were added to 655.7 parts of 99.72% 6-tert-butyl-2,4-dimethylanisole, the stirring was started, the temperature was raised to 190°C for reaction, and after 2 hours of reaction, sampling and analysis showed that the content of 4-tert-butyl-2,4-dimethylanisole was 0.34%, which was qualified. 35.4 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5, the layers were separated, and the material layer was vacuum distilled (theoretical plate 200, pressure -0.085 MPa, reflux ratio 8: 1) to obtain 441.6 parts of 99.9% 2,4-dimethylanisole and 186.6 parts of isobutylene were recovered for application.

[0138] The fourth transition fraction is re-distilled to obtain ≥99% of 6-tert-butyl-2,4-dimethylanisole.

[0139] To the third still residual 464.5 parts (463.1 parts of 4-tert-butyl-2,5-dimethylanisole) were added 9.8 parts of 98% concentrated sulfuric acid (2.11% by mass of 4-tert-butyl-2,5-dimethylanisole), stirring was started, and the reaction was warmed to 185°C. After 2.5 hours of reaction, sampling and analysis showed that the 4-tert-butyl-2,5-dimethylanisole content was 0.33% qualified. Then, 25.3 parts of 31% alkali liquor were added to the reaction product to neutralize it to a pH of 7.5. Layering was performed, and the material layer was distilled under reduced pressure (theoretical plate 200, pressure-0.085 MPa, reflux ratio 10: 1) to obtain 99.85% 2,311.7 parts of 5-dimethylanisole successively, and 131.5 parts of isobutylene were recovered and used mechanically.

[0140] (6) Synthesis of 2,5-dimethylphenol

[0141] Add 311.7 parts of 99.85% 2,5-dimethylanisole and 400 parts of mixed trimethylbenzene to the reactor, heat to 135-140°C, add 47% hydrobromic acid dropwise to react, and the bromomethane gas generated by the reaction is cooled to -10°C through a condenser and two cold traps and enters a bromoalkane storage tank (-15°C). After the reaction is completed, stop collecting bromoalkanes, add 687.2 parts of 47% hydrobromic acid dropwise, collect 210.3 parts of bromomethane, and the yield is 96%. .8%; the reaction solution was then cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 20 parts of water, the layers were separated, and the water layers were combined to obtain 497 parts of 26.7% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), 393 parts of trimethylbenzene were recovered from the material layer distillation kettle and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 5:1) to obtain 260.1 parts of 99.91% 2,5-xylenol, with a yield of 93.1%.

[0142] Example 4

[0143] A method for synthesizing anisole products using cresol fractions comprises the following steps:

[0144] (1) Etherification reaction

[0145] 3000 parts of cresol fraction (composed of 22.91% o-cresol, 15.67% 2,6-dimethylphenol, 23% m-cresol, 15.33% p-cresol, 6.08% o-ethylphenol, 9.75% 2,4-dimethylphenol, 6.92% 2,5-dimethylphenol), 30 parts of 6-tert-butyl-2,4-dimethylphenol, 90 parts of basic catalyst DBN (1,5-diazabicyclo[4.3.0]non-5-ene), 60 parts of potassium chloride, and 30 parts of magnesium carbonate were added to the reactor and the temperature was raised to 80°C. Stir for 1.5 hours, add 3400 parts of dimethyl carbonate (the molar ratio of dimethyl carbonate to phenolic substances is 1.42:1), seal the reactor, heat to 190-200 ° C for insulation reaction, reaction pressure 6.3 MPa, react for 6 hours and take samples for analysis, 0.11% of m-cresol is qualified, cool to 80 ° C and filter, filter cake re-use, add 180 parts of water to the filtrate and stir, add 35 parts of sulfuric acid dropwise and wash for 1 hour to remove aniline and pyridine base, the pH of the aqueous solution is 4, layered, the material layer is washed with 120 parts of water, and the water is completely separated to obtain the material layer.

[0146] (2) Etherification distillation separation

[0147] The above material layer was added to a distillation kettle (theoretical plate 250), 15 parts of 98% sulfuric acid was added, and vacuum distillation was carried out (-0.085 MPa) at a reflux ratio of 20 to 25:1. The total reflux was carried out for 1 hour after every 3 hours of distillation. Under chromatographic analysis, 517.8 parts of 99.59% o-methyl anisole (99.59% o-methyl anisole, 0.36% m- / p-methyl anisole, and 0.05% others) were accurately collected. 1951.4 parts of the first mixed fraction (252.3 parts of o-methyl anisole, 770.2 parts of m-methyl anisole, 513.4 parts of p-methyl anisole, 214.8 parts of 2,6-dimethyl anisole, and 200.7 parts of o-ethyl anisole) and 302.5 parts of 99.57% 2,6-dimethyl anisole (0. 25%, 2,6-dimethylanisole 99.57%, 2,4 / 2,5-dimethylanisole 0.15%, others 0.03%), 23.8 parts of the second mixed fraction (2.4 parts of 2,6-dimethylanisole, 12.5 parts of 2,4-dimethylanisole, 8.9 parts of 2,5-dimethylanisole), 504.7 parts of 99.86% 2,4 / 2,5-dimethylanisole (0.3 part of 2,6-dimethylanisole, 294.8 parts of 2,4-dimethylanisole, 209.2 parts of 2,5-dimethylanisole, and 0.4 part of others) and 126 parts of the first kettle residue (including 14.9 parts of 2,4-dimethylanisole, 10.6 parts of 2,5-dimethylanisole, 10.7 parts of others and 89.8 parts of DBN).

[0148] The residue from the first batch was used in the next batch of cresol etherification reaction; 99.59% o-methylanisole and 99.57% 2,6-dimethylanisole products were sold out.

[0149] The second mixed fraction is combined in multiple batches and then distilled to obtain pure 2,6-dimethylanisole and 2,4 / 2,5-dimethylanisole.

[0150] (3) Tertiary butylation separation of the first mixed fraction

[0151] 1951.4 parts of the first mixed fraction (252.3 parts of o-methyl anisole, 770.2 parts of m-methyl anisole, 513.4 parts of p-methyl anisole, 214.8 parts of 2,6-dimethyl anisole, 200.7 parts of o-ethyl anisole) obtained in step (2) and 75 parts of sulfuric acid (3.8% of the mass of the first mixed fraction) were added to the reactor. After heating to 90° C. with stirring, 2500 parts of isobutylene (1.28 times the mass of the first mixed fraction) were introduced to react. The isobutylene was introduced for 7 hours. After the reaction was completed and kept warm for 2.5 hours, sampling and analysis were performed. 6-tert-butyl-3-methyl anisole 0 .11% qualified, 652 parts of isobutylene were recovered and used; then 194.5 parts of 31% liquid alkali were added to neutralize to pH 7.5, the water layer was separated, and the material layer was added to a high-efficiency distillation tower (theoretical plate 250, pressure -0.095MPa, reflux ratio 5:1), and distilled at a reflux ratio of 20 to 25:1 to obtain 129.5 parts of diisobutylene, 280.5 parts of 99.42% 4-tert-butyl-2,6-dimethylanisole, 114.4 parts of the first transition fraction (21 parts of 4-tert-butyl-2,6-dimethylanisole, 31.9 parts of 4,6-di-tert-butyl-2-methylanisole, 2,6-di-tert-butyl-3-methylanisole, 31.9 parts of 4 ... 61.5 parts of 4-tert-butyl-4-methylanisole), 99.83% mixed di-tert-butylanisole 1305.5 parts (0.03% of 4-tert-butyl-2,6-dimethylanisole, 32.8% of 4,6-di-tert-butyl-2-methylanisole, 67.03% of 2,6-di-tert-butyl-4-methylanisole, 0.14% of 4,6-di-tert-butyl-2-ethylanisole), 98.9 parts of the second transition fraction (17.6 parts of 4,6-di-tert-butyl-2-methylanisole, 36.3 parts of 2,6-di-tert-butyl-4-methylanisole, 45 parts of 4,6-di-tert-butyl-2-ethylanisole), 9.83% 292.2 parts of 4,6-di-tert-butyl-2-ethylanisole (0.1 part of 4,6-di-tert-butyl-2-methylanisole, 0.2 part of 2,6-di-tert-butyl-4-methylanisole, 291.7 parts of 4,6-di-tert-butyl-2-ethylanisole, 0.2 part of 4,6-di-tert-butyl-3-methylanisole), 86.1 parts of the third transition fraction (24 parts of 4,6-di-tert-butyl-2-ethylanisole, 62.1 parts of 4,6-di-tert-butyl-3-methylanisole) and 1402.1 parts of the second kettle residue (1400.2 parts of 4,6-di-tert-butyl-3-methylanisole).

[0152] The first transition fraction is re-distilled to obtain 99% 4-tert-butyl-2,6-dimethylanisole, a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole; the second transition fraction is re-distilled to obtain a mixture of 4,6-di-tert-butyl-2-methylanisole and 2,6-di-tert-butyl-4-methylanisole, and 99% 4,6-di-tert-butyl-2-ethylanisole; the third transition fraction is re-distilled to obtain 99% 4,6-di-tert-butyl-2-ethylanisole, leaving a distillation pot residue (4,6-di-tert-butyl-3-methylanisole).

[0153] (4) Deisobutylene and distillation of tert-butyl compounds

[0154] S1: To 280.5 parts of 99.42% 4-tert-butyl-2,6-dimethylanisole obtained in step (3), 4.5 parts of 98% concentrated sulfuric acid (1.6% of the mass of 4-tert-butyl-2,6-dimethylanisole) were added, stirring was started, and the temperature was raised to 195°C for reaction. After reacting for 2 hours, sampling and analysis were performed, and the 4-tert-butyl-2,6-dimethylanisole content was 0.08%, which was qualified. Then, 11.7 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The mixture was separated into layers and vacuum distilled (theoretical plate 200, pressure -0.080 MPa, reflux ratio 8:1) to obtain 184.9 parts of 99.7% 2,6-dimethylanisole in sequence, with a yield of 93.3%, and 79.5 parts of isobutylene were recovered for use.

[0155] S2: To 1305.5 parts of 99.83% mixed di-tert-butylanisole (0.03% of 4-tert-butyl-2,6-dimethylanisole, 32.8% of 4,6-di-tert-butyl-2-methylanisole, 67.03% of 2,6-di-tert-butyl-4-methylanisole, and 0.14% of 4,6-di-tert-butyl-2-ethylanisole) obtained in step (3) were added 23 parts of 98% concentrated sulfuric acid (1.76% of the mass of the mixed di-tert-butylphenol), stirring was started, the temperature was raised to 185°C, and the reaction was carried out for 3 hours. Samples were taken for analysis, and 2- Tert-butyl-4-methylanisole content 0.18% is qualified, and in reaction product, adding 59.8 parts of 31% alkali lyes to be neutralized to pH is 8 again, layering, material layer rectification under vacuum (theoretical plate 200, pressure-0.080MPa, reflux ratio 25:1) obtains 185.1 parts of 99.56% o-methylanisole, 117.4 parts of middle distillates (36.3 parts of o-methylanisole, 81 parts of p-methylanisole, other 0.1 part), 370.9 parts of 99.75% p-methylanisole successively, reclaim 612.3 parts of iso-butylenes and use mechanically.

[0156] S3: To 292.2 parts of 99.83% 4,6-di-tert-butyl-2-ethylanisole (0.1 part of 4,6-di-tert-butyl-2-methylanisole, 0.2 part of 2,6-di-tert-butyl-4-methylanisole, 291.7 parts of 4,6-di-tert-butyl-2-ethylanisole, and 0.2 part of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3) were added 6 parts of 98% concentrated sulfuric acid (2.0 parts of the mass of 4,6-di-tert-butyl-2-ethylanisole). 5%), start stirring, heat to 190 ° C for reaction, react for 2 hours, take samples for analysis, 6-tert-butyl-2-ethylanisole content 0.21% qualified, then add 31% alkali solution 15.5 parts to the reaction product to neutralize to pH 7.5, separate layers, and conduct vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 5: 1) of the material layer to obtain 99.71% o-ethylanisole 195.4 parts, a yield of 94.2%, and recover 83.2 parts of isobutylene for use.

[0157] S4: To 1402.1 parts of the second kettle residue (1400.2 parts of 4,6-di-tert-butyl-3-methylanisole) obtained in step (3) were added 35.4 parts of 98% concentrated sulfuric acid (2.52% of the mass of the kettle residue), stirring was started, the temperature was raised to 200°C for reaction, and the reaction was carried out for 1.5 hours. Sampling and analysis showed that the 6-tert-butyl-3-methylanisole content was 0.13%, which was qualified. Then, 91.4 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5. The mixture was separated and the material layer was subjected to vacuum distillation (theoretical plate 200, pressure -0.080 MPa, reflux ratio 10:1) to obtain 693.8 parts of 99.82% m-methylanisole with a yield of 94.1%, and 654.8 parts of isobutylene were recovered for use.

[0158] The distillation still residue in step (3) is subjected to deisobutylene, neutralization and distillation according to the method of the second still residue to obtain ≥99% of m-methyl anisole.

[0159] (5) Separation of 2,4 / 2,5-dimethylanisole

[0160] 504.7 parts of 99.86% 2,4 / 2,5-dimethylanisole (0.3 parts of 2,6-dimethylanisole, 294.8 parts of 2,4-dimethylanisole, 209.2 parts of 2,5-dimethylanisole, and 0.4 parts of others) and 8 parts of 98% sulfuric acid (1.59% of the mass of 2,4 / 2,5-dimethylanisole) obtained in step (2) were added to the reactor. After heating to 110° C. with stirring, 590 parts of isobutylene (1.17 times the mass of 2,4 / 2,5-dimethylanisole) were introduced to react. The isobutylene was introduced for 5.5 hours. After the reaction was completed and kept warm for 2 hours, sampling and analysis were performed. 2,4-dimethylanisole 0.28% of anisole was qualified, and then 20.7 parts of 31% liquid caustic soda was added to neutralize it to a pH of 7.5, the water layer was separated, and the material layer was added into a high-efficiency distillation tower (theoretical plate 200, pressure-0.090 MPa), and distilled at a reflux ratio of 10:1 to obtain 47.3 parts of diisobutylene, 99.72% of 6-tert-butyl-2, 393.2 parts of 4-dimethylanisole, 27.5 parts of the fourth transition fraction (19.3 parts of 6-tert-butyl-2, 4-dimethylanisole and 14.2 parts of 4-tert-butyl-2, 5-dimethylanisole), and 278.7 parts of the third kettle residue (277.8 parts of 4-tert-butyl-2, 5-dimethylanisole).

[0161] Subsequently, 8 parts of 98% concentrated sulfuric acid (2.03% of the mass of 6-tert-butyl-2,4-dimethylanisole) were added to 393.2 parts of 99.72% 6-tert-butyl-2,4-dimethylanisole, stirring was started, the temperature was raised to 190°C for reaction, and after 2 hours of reaction, sampling and analysis showed that the content of 4-tert-butyl-2,4-dimethylanisole was qualified at 0.27%. 20.7 parts of 31% alkali solution were added to the reaction product to neutralize it to a pH of 7.5, and the layers were separated. The material layer was vacuum distilled (theoretical plate 200, pressure -0.085 MPa, reflux ratio 5: 1) to obtain 265.2 parts of 99.8% 2,4-dimethylanisole, and 112 parts of isobutylene were recovered for application.

[0162] The fourth transition fraction is re-distilled to obtain ≥99% of 6-tert-butyl-2,4-dimethylanisole.

[0163] To the third still residual 278.7 parts (4-tert-butyl-2,5-dimethylanisole 277.8 parts) were added 6 parts of 98% concentrated sulfuric acid (4-tert-butyl-2,5-dimethylanisole mass 2.15%), started stirring, warmed to 185 ° C reaction, reacted for 2.5 hours, sampled and analyzed, 4-tert-butyl-2,5-dimethylanisole content 0.32% qualified, then added 31% alkali liquor 15.5 parts in the reaction product to neutralize to pH 7.5, layered, material layer vacuum distillation (theoretical plate 200, pressure-0.085 MPa, reflux ratio 10: 1) to obtain 99.72% 2,5-dimethylanisole 187.2 parts successively, and 78.9 parts of isobutylene were recovered and used mechanically.

[0164] (6) Synthesis of 2,5-dimethylphenol

[0165] Add 187.2 parts of 99.72% 2,5-dimethylanisole and 300 parts of mixed trimethylbenzene to the reactor, heat to 130-140°C, add 47% hydrobromic acid dropwise to react, and the bromomethane gas generated by the reaction is cooled to -10°C through a condenser and two cold traps and enters a bromoalkane storage tank (-15°C). After the reaction is completed, stop collecting bromoalkanes, add 412 parts of 47% hydrobromic acid dropwise, collect 125.3 parts of bromomethane, and the yield is 0.01%. 96.1%; then the reaction liquid was cooled slightly to separate the hydrobromic acid aqueous solution, the solvent layer was washed once with 12 parts of water, the layers were separated, and the water layers were combined to obtain 298.2 parts of 26.7% hydrobromic acid solution (47% of the hydrobromic acid was recovered by heating), and 293 parts of trimethylbenzene were recovered in the distillation kettle of the material layer and then distilled (theoretical plate 160, pressure -0.085 MPa, reflux ratio 5:1) to obtain 155.8 parts of 99.91% 2,5-xylenol.

[0166] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0167] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for synthesizing anisole products using cresol fractions, characterized in that: The following steps are involved: (1) adding an alkaline catalyst and a protective agent to the cresol fraction, heating and stirring, and then adding an alkylating agent to carry out an etherification reaction, and then standing and stratifying the reaction product, washing, to obtain a material layer; (2) subjecting the material layer obtained in step (2) to a rectification treatment to obtain o-methyl anisole, a first mixed fraction, 2,6-dimethyl anisole, a second mixed fraction, 2,4 / 2,5-dimethyl anisole, and a first still residue; (3) adding sulfuric acid to the first mixed fraction obtained in step (2), stirring and heating, and then introducing isobutylene to carry out heat-insulating reaction, and then adding liquid alkali to neutralize to a pH of 7 to 8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 4-tert-butyl-2,6-dimethylanisole, a first transition fraction, mixed di-tert-butylanisole, a second transition fraction, 4,6-di-tert-butyl-2-ethylanisole, a third transition fraction, and a second still residue; (4) adding concentrated sulfuric acid to the 4-tert-butyl-2,6-dimethylanisole, the mixed di-tert-butylanisole, and the 4,6-di-tert-butyl-2-ethylanisole obtained in step (3), stirring and heating, and reacting them respectively. After the reaction is completed, adding alkali solution to the reaction product to neutralize it to a pH of 7 to 8, separating the layers, and subjecting the obtained material layers to vacuum distillation to obtain 2,6-dimethylanisole, o-methylanisole, p-methylanisole, o-ethylanisole, and isobutylene; (5) adding sulfuric acid to the 2,4 / 2,5-dimethylanisole obtained in step (2), stirring and heating, then introducing isobutylene to carry out heat-insulating reaction, then adding liquid alkali to neutralize to a pH of 7-8, separating the water layer, and rectifying the obtained material layer to obtain diisobutylene, 6-tert-butyl-2,4-dimethylanisole, a fourth transition fraction, and a third still residue; then adding concentrated sulfuric acid to the 6-tert-butyl-2,4-dimethylanisole, stirring and heating to react, and adding alkali solution to the reaction product to neutralize to a pH of 7-8, separating the layers, and rectifying the obtained material layer under reduced pressure to obtain 2,4-dimethylanisole and isobutylene.

2. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (1), the cresol fraction comprises 0.1-60% of o-cresol, 0.1-25% of 2,6-dimethylphenol, 30-100% of m-para-cresol, 0.1-20% of 2,4 / 2,5-dimethylphenol, and 0.1-20% of o-ethylphenol; and / or, the alkaline catalyst comprises at least one of an aqueous solution of an alkali metal or alkaline earth metal hydroxide, an organic amine substance or an alkaline substance supported on a carrier, an alkali metal or alkaline earth metal halide, and a mixture of a water-insoluble metal carbonate; And / or, the protective agent is at least one of the antioxidant BHT, antioxidant BHA, and 6-tert-butyl-2,4-dimethylphenol; And / or, the alkylating agent includes at least one of iodoalkanes, chloroalkanes, di-fatty sulfates or di-fatty carbonates.

3. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (1), the mass ratio of the phenolic substances in the cresol fraction to the protective agent is 1:(0.0001-0.02); And / or, the molar ratio of the phenolic substances in the cresol fraction to the alkylating agent is 1:(0.5-5).

4. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (1), the heating and stirring temperature is 30 to 80° C., and the stirring time is 0.5 to 2 h; And / or, the reaction temperature of the etherification reaction is 0-200° C., the reaction time is 2-20 h, and the pressure required for the etherification reaction is 0-8 MPa.

5. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (1), the static stratification is carried out at 70-90°C; And / or, the washing includes: adding sulfuric acid solution to the material layer obtained after standing and stratifying, washing for 0.5 to 2 hours, and then washing the obtained material layer with water after stratification, and removing the washing water to obtain the material layer.

6. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (2), the theoretical plate of the distillation treatment is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (10 to 30):

1.

7. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (3), the amount of sulfuric acid added is 1 to 5% of the mass of the first mixed fraction; And / or, the amount of isobutylene introduced is 1 to 3 times the mass of the first mixed fraction, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 30):

1.

8. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (4), the stirring and heating temperature is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-30):

1.

9. The method for synthesizing anisole products by utilizing cresol fraction according to claim 1, wherein In the step (5), the amount of sulfuric acid added is 1 to 5% of the mass of the 2,4 / 2,5-dimethylanisole; And / or, the amount of isobutylene introduced is 0.5 to 2 times the mass of the 2,4 / 2,5-dimethylanisole, the reaction temperature of the insulation reaction is 60 to 120° C., and the reaction time is 1 to 3 hours; the theoretical plate of the distillation is 100 to 300, the pressure is -0.05 to -0.1 MPa, and the reflux ratio is (5 to 15):

1.

10. The method for synthesizing anisole products using cresol fractions according to claim 1, wherein In the step (5), when concentrated sulfuric acid is added to the 6-tert-butyl-2,4-dimethylanisole, the amount of the concentrated sulfuric acid added is 0.5 to 3%; And / or, the reaction temperature of the stirring temperature-raising reaction is 180-200° C., and the reaction time is 1-3 h; the theoretical plate of the vacuum distillation is 100-300, the pressure is -0.05-0.1 MPa, and the reflux ratio is (5-15):1.