A high-efficiency and clean production method of phenolic compounds

Abstract

The application discloses a high-efficiency and clean production method of phenolic compounds. The method comprises the following steps: adding corresponding aromatic amine compounds into a certain amount of acid catalyst aqueous solution, heating and hydrolyzing, reducing to room temperature, adding an extraction solvent to extract generated phenolic compounds, removing the extraction solvent from the extraction liquid to prepare phenolic compound products, mixing a certain amount of polar protic solvent into the extraction liquid after the extraction, and precipitating and separating inorganic ammonium salt in the mother liquor, wherein the salt, the aromatic amine compounds which are not hydrolyzed or are incompletely hydrolyzed, the acid catalyst and the excess acid catalyst are dissolved in the polar protic solvent, and the inorganic ammonium salt is separated; and further distilling and removing the polar protic solvent to separate the salt of the aromatic amine compounds which are not hydrolyzed or are incompletely hydrolyzed and the excess acid catalyst, and the separated salt is used for the synthesis of the next batch of products to continue the hydrolysis reaction.

Description

[0001] I. TECHNICAL FIELD: The present application belongs to the technical field of chemical raw material synthesis, especially a high-efficiency and clean production method of phenolic compounds is designed.

[0002] II. BACKGROUND: Phenolic compounds are an important class of chemical raw materials, which have a very wide range of applications and are closely related to human production and life, and can be applied to medicine, pesticides, veterinary drugs, materials, adjuvants, dyes, pigments, coatings, adhesives, plastics, rubber, electronic chemicals, etc. There are many methods for preparing this kind of compounds, including: sulfonate base fusion method, amino compound acid hydrolysis method, amino diazotization hydrolysis method, hydrogen peroxide hydroxylation method, isopropyl compound oxidative hydrolysis method, halogenated hydrocarbon alkaline hydrolysis method, hydroxylamine rephotography method, etc.

[0003] Due to the positioning effect or related environmental protection, safety, technology, resources and other reasons, with the development of science and technology and materials, the acid hydrolysis of arylamine compounds to convert the amino group into hydroxyl group to prepare the corresponding phenolic compounds has gradually become the main industrialized preparation method for some phenolic compounds, such as: p-methylphenol, m-methylphenol, 2-naphthol, 1-naphthol, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 3, 5-dimethylphenol, p-phenylphenol, p-benzoquinol, m-benzoquinol, 2, 4-dihydroxytoluene, 2-methyl-m-benzoquinol, m-benzotriol, 1, 5-dihydroxynaphthalene, 3, 5-dihydroxybenzoic acid, 2, 5-dimethylphenol, 3, 4-dimethylphenol, 8-hydroxyquinoline, 4-hydroxydiphenylamine, etc.

[0004] The main reaction process is as follows:

[0005] 1. Preparation of p-cresol by acid hydrolysis of p-methylaniline:

[0006]

[0007] 2. Preparation of m-benzoquinol by acid hydrolysis of m-phenylenediamine:

[0008]

[0009] 3. Preparation of m-hydroxybenzoic acid from m-aminobenzoic acid:

[0010]

[0011] 4. Preparation of 2, 4-dihydroxytoluene by acid hydrolysis of 2, 4-diaminotoluene:

[0012]

[0013] 5. Preparation of 2, 6-dihydroxytoluene by acid hydrolysis of 2, 6-diaminotoluene:

[0014]

[0015] While the commonly used acid for hydrolyzing arylamine compounds is sulfuric acid, ammonium bisulfate, hydrochloric acid, hydrobromic acid, phosphoric acid, etc., when sulfuric acid is used as the catalyst in the conventional method for hydrolyzing arylamine compounds to prepare corresponding phenolic compounds, the acid excess is relatively large, the utilization rate of the acid radical is less than 50%, the mother liquor after extracting the phenolic compounds is generally neutralized with ammonia gas to remove the residual acid, and the concentrated product is used to prepare by-product ammonium sulfate, while the raw materials and intermediates that are not completely hydrolyzed are difficult to recycle and utilize; when ammonium bisulfate is used as the catalyst, the acid excess is also relatively large, high temperature is required for converting the generated ammonium sulfate into ammonium bisulfate, and the raw materials and intermediates that are not completely hydrolyzed are destroyed and difficult to continue to utilize; when phosphoric acid is used as the catalyst, the acid excess is relatively large, in some literatures, the phosphoric acid aqueous solution after hydrolysis is continuously used for 5-6 times after adding the consumed phosphoric acid, so that the utilization rate of the catalyst and the raw materials is improved, but finally a large amount of acidic mixed mother liquor cannot be treated, the raw materials and intermediates that are not completely hydrolyzed are difficult to recycle and utilize, and a large amount of phosphoric acid has to be neutralized with ammonia to prepare by-product ammonium phosphate.

[0016] However, no matter how the arylamine compounds are hydrolyzed, a certain amount of waste acid will be generated, which not only contains part of the raw materials and intermediates, but also needs to be neutralized with alkaline substances to treat the waste mother liquor, resulting in a large amount of waste salt impurities and great environmental hazards, and the product yield is low.

[0017] III. Invention content: (1) Invention purpose: The present application is to overcome the problems of incomplete hydrolysis reaction, low raw material conversion rate, low utilization efficiency of the catalyst in the neutralization treatment of the hydrolysis mother liquor, and great environmental hazards in the known method for preparing phenolic compounds by using corresponding arylamine compounds for acid hydrolysis, to find a method for recycling and using the ammonium salt generated by simple precipitation of the mother liquor with a stable hydrolysis catalyst, to improve the product yield and the utilization efficiency of the catalyst, to reduce the environmental hazards, and to form an efficient, clean and safe process for preparing phenolic compounds.

[0018] (2) Technical scheme: Through a large number of experimental studies, it is found that in the sulfuric acid, ammonium bisulfate, phosphoric acid, hydrochloric acid, and hydrobromic acid used in the conventional hydrolysis of arylamine compounds to prepare corresponding phenolic compounds, the solubility of the inorganic ammonium salt formed in the polar protic solvent is small, while the amine salt formed with arylamine compounds has a certain solubility, and by proper design, the inorganic ammonium salt generated in the hydrolysis reaction can be precipitated and separated from the hydrolysis reaction system, and the amine salt formed by arylamine compounds and the acidic catalyst can be recycled and used in the hydrolysis reaction after separating the polar protic solvent, so that an efficient, clean and cyclic process for preparing phenolic compounds by acid hydrolysis of arylamine compounds is formed.

[0019] (3)Technical effects: the present application is a high-efficiency and clean production method of phenolic compounds, which comprises the following steps: adding corresponding aromatic amine compounds into a certain amount of acid catalyst aqueous solution, hydrolyzing after heating, reducing to room temperature, adding extraction solvent to extract the generated phenolic compounds, preparing phenolic compound products after removing the extraction solvent from the extraction liquid, mixing a certain amount of polar protic solvent into the extraction liquid after the extraction, precipitating and separating the inorganic ammonium salt in the mother liquor, dissolving the salt of aromatic amine compounds and the acid catalyst in the polar protic solvent, and removing the polar protic solvent after separating the inorganic ammonium salt, so that the salt of aromatic amine compounds and the acid catalyst can be used for the synthesis of the next batch, and the water hydrolysis reaction can continue. In this way, the product yield is improved, the use efficiency of the catalyst is improved, the environmental hazards are reduced, and the process method is efficient, clean and safe.

[0020] Specifically embodied in the following aspects:

[0021] 1. The present application uses polar protic solvent as a precipitation solvent, so that the solubility of the generated inorganic ammonium salt in the polar protic solvent is small, and the addition of the polar protic solvent can easily precipitate and separate, so that the acid catalyst in the hydrolysis mother liquor can be conveniently recovered and reused, thereby improving the use efficiency of the catalyst, reducing the production cost, and reducing the environmental hazards.

[0022] 2. The present application uses polar protic solvent as a precipitation solvent, so that the salt of the aromatic amine compounds and the catalyst which are not hydrolyzed or incompletely hydrolyzed can be dissolved in the polar protic solvent, so that the part of the compounds can be continuously reused in the hydrolysis reaction, thereby improving the conversion rate of the raw materials, reducing the production cost, and reducing the environmental hazards.

[0023] Fourth, the specific embodiment of the present application is as follows:

[0024] Example 1: 85% phosphoric acid 176g, water 201.5g, and 2,4-diaminotoluene 27g were added into a 500ml hydrolysis reaction tank, mixed uniformly, and then nitrogen was replaced and pressurized to 230-240℃ for 6 hours. After cooling, 391.2g of hydrolysis liquid was obtained (loss 13.3g). The hydrolysis liquid was transferred into a separatory funnel, 50ml of butyl acetate was added each time, and extraction was carried out 4 times. The combined extraction liquid was dried with magnesium sulfate, and then decolorized with activated carbon. Butyl acetate was removed under vacuum, toluene was added for crystallization, and then filtered and dried to obtain 22.5g of light brown 2,4-dihydroxytoluene (molar yield 82%)

[0025] The acidic mother liquor after extraction, heating to distill the azeotrope of butyl acetate and water, the residual 320g of acidic mother liquor is added to 1500g of methanol, there is transparent crystal precipitate, washed with methanol and filtered, the crystal is dried to obtain 39g of ammonium dihydrogen phosphate (TLC analysis, almost organic matter), the mother liquor continues to heat to distill methanol, the residual 250g of mother liquor (TCL analysis, 2, 4-diaminotoluene and other components), titration analysis contains phosphoric acid 103.5g, save for the next batch of hydrolysis.

[0026] Example 2: In a 500ml hydrolysis reaction tank, add 85% phosphoric acid 51g, water 82g, mix evenly, then add 2, 4-diaminotoluene 27g, and then use the recovered mother liquor 245g in example 1, replace with nitrogen, and then pressurize and heat to 230-240℃ for 6 hours, cool down and take out the hydrolysis liquid 393g (loss 12g), transfer the hydrolysis liquid into a separatory funnel, add 50ml of butyl acetate each time and extract 4 times, combine the extract, dry with magnesium sulfate, decolorize with activated carbon, then vacuum remove butyl acetate, add toluene to crystallize, filter and dry to obtain 25.5g of 2, 4-dihydroxytoluene (molar yield 92.9%) of light brown color.

[0027] The acidic mother liquor after extraction, heating to distill the azeotrope of butyl acetate and water, the residual 322g of acidic mother liquor is added to 1500g of methanol, there is transparent crystal precipitate, washed with methanol and filtered, the crystal is dried to obtain 45.5g of ammonium dihydrogen phosphate (TLC analysis, almost organic matter), the mother liquor continues to heat to distill methanol, the residual 255g of mother liquor (TCL analysis, 2, 4-diaminotoluene and other components), titration analysis contains phosphoric acid 106g, save for the next batch of hydrolysis.

[0028] Example 3: In a 500ml hydrolysis reaction tank, add 98% sulfuric acid 90g, water 280g, mix evenly, then add m-phenylenediamine 46g, replace with nitrogen, then pressurize and heat to 230-240℃ for 6 hours, cool down and take out the hydrolysis liquid 401g (loss 15g), transfer the hydrolysis liquid into a separatory funnel, add 80ml of butyl acetate each time and extract 4 times, combine the extract, dry with magnesium sulfate, decolorize with activated carbon, then vacuum remove butyl acetate, add toluene to crystallize, filter and dry to obtain 39.8g of m-dihydroxybenzene (molar yield 85%) of light brown color.

[0029] The acidic mother liquor after extraction, heating to distill the azeotrope of butyl acetate and water, the residual 290g of acidic mother liquor is added to 1500g of ethanol, there is transparent crystal precipitate, washed with ethanol and filtered, the crystal is dried to obtain 79g of ammonium bisulfate (TLC analysis, almost organic matter), the mother liquor continues to heat to distill ethanol, the residual 185g of mother liquor (TCL analysis, contains m-phenylenediamine and other components), titration analysis contains sulfuric acid 4.2g, save the mother liquor for the next batch of hydrolysis.

[0030] Example 4: In a 500ml hydrolysis reactor, add 90g of 98% sulfuric acid, 118g of water, 182g of mother liquor recovered from Example 3, mix well, then add 46g of m-phenylenediamine, replace with nitrogen, and pressurize to heat to 230-240°C for 6 hours. After cooling, remove 424g of hydrolysis solution (loss 12g). Transfer the hydrolysis solution to a separatory funnel, and extract 4 times with 80ml of butyl acetate each time. Combine the extract, dry with magnesium sulfate, decolorize with activated carbon, remove butyl acetate under vacuum, add toluene to crystallize, filter, and dry to obtain 44.3g of m-dihydroxybenzene (molar yield 94.5%) as a light brown color.

[0031] The acidic mother liquor after extraction is heated to distill off the butyl acetate and water azeotrope. Add 1500g of ethanol to the remaining 305g of acidic mother liquor, and allow transparent crystals to precipitate. Wash and filter the crystals, and dry to obtain 90.5g of ammonium bisulfate (TLC analysis shows almost no organic matter). Continue to heat and distill off the ethanol from the mother liquor, and obtain 194g of mother liquor (TLC analysis shows that it contains m-phenylenediamine and other components). Titration analysis shows that it contains 7.9g of sulfuric acid. Save the mother liquor for use in the next batch of hydrolysis.

[0032] Example 5: In a 500ml hydrolysis reactor, add 190g of ammonium bisulfate (90%), and 210g of water, mix well, then add 27g of 2,4-diaminotoluene, replace with nitrogen, and pressurize to heat to 230-240°C for 6 hours. After cooling, remove 414g of hydrolysis solution (loss 13g). Transfer the hydrolysis solution to a separatory funnel, and extract 4 times with 50ml of butyl acetate each time. Combine the extract, dry with magnesium sulfate, decolorize with activated carbon, remove butyl acetate under vacuum, add toluene to crystallize, filter, and dry to obtain 20.5g of 2,4-dihydroxytoluene (molar yield 74.7%) as a light brown color.

[0033] The acidic mother liquor after extraction is heated to distill off the butyl acetate and water azeotrope. Add 1500g of ethanol to the remaining 305g of acidic mother liquor, and allow transparent crystals to precipitate. Wash and filter the crystals, and dry to obtain 90.5g of ammonium bisulfate (TLC analysis shows almost no organic matter). Continue to heat and distill off the ethanol from the mother liquor, and obtain 194g of mother liquor (TLC analysis shows that it contains m-phenylenediamine and other components). Titration analysis shows that it contains 7.9g of sulfuric acid. Save the mother liquor for use in the next batch of hydrolysis.

[0034] Example 6: In a 500ml hydrolysis reactor, 50g of 90% ammonium bisulfate, 80g of water, and 267g of the recovered mother liquor from Example 5 were mixed uniformly, then 27g of 2,4-diaminotoluene was added, and after nitrogen replacement, the temperature was raised to 230-240°C under pressure for 6 hours. After cooling, 413g of hydrolysis solution was obtained (loss 11g). The hydrolysis solution was transferred to a separatory funnel, and 50ml of butyl acetate was added each time for extraction 4 times. The combined extract was dried over magnesium sulfate and decolorized with activated carbon, then butyl acetate was removed under vacuum, and toluene was added for crystallization. After filtration and drying, 23.7g of 2,4-dihydroxytoluene was obtained as a light brown color (molar yield 86.4%)

[0035] The acidic mother liquor after extraction was heated to evaporate the butyl acetate and water azeotrope. 315g of the residual acidic mother liquor was added to 700g of methanol, and transparent crystals were precipitated. After washing with methanol, filtration, and drying, 48.5g of diammonium sulfate was obtained (TLC analysis, almost no organic matter). The mother liquor was continuously heated to evaporate the methanol, and 254g of the residual mother liquor was obtained (TLC analysis, 2,4-diaminotoluene and other components). Titration analysis showed that the mother liquor contained 116g of ammonium bisulfate. The mother liquor was stored for use in the next batch of hydrolysis.

[0036] The present application is a clean production method of phenolic compounds, which solves the problems of low raw material conversion rate, neutralization treatment of hydrolysis mother liquor, and environmental hazards in the production of phenolic compounds by acid hydrolysis of corresponding aromatic amine compounds. In the production of phenolic compounds by acid hydrolysis of corresponding aromatic amine compounds using an acidic catalyst, a polar protic solvent is used as a precipitant, and the inorganic ammonium salt precipitated is separated from the system, and the salt formed by the unhydrolyzed and incompletely hydrolyzed aromatic amine compounds, the acidic catalyst, and the excess acidic catalyst are dissolved, so that they can be recycled and used, which not only improves the product yield and the efficiency of the catalyst, but also completely solves the problem of hydrolysis mother liquor, reduces environmental hazards, and makes the process efficient, clean, and safe. The raw materials are easy to obtain, suitable for batch and continuous production, and have high automation degree, no need for alkaline neutralizing agent to treat wastewater, safety and environmental protection, high yield, good quality, low cost, and can be used for industrial production. The present application has low investment cost, low production risk, and high operating profit.

[0037] Finally, it should be noted that the above description is only a preferred batch synthesis embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples, or make equivalent replacements to some of the technical features, or just use the technology of the present application as a continuous engineering. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A high-efficiency and clean production method of phenolic compounds, which comprises adding a corresponding aromatic amine compound into a certain amount of an acidic catalyst aqueous solution, heating and hydrolyzing, then lowering the temperature to room temperature, adding an extraction solvent to extract the generated phenolic compounds, removing the extraction solvent from the extract to prepare the phenolic compound product, evaporating the residual extraction solvent and part of the water from the acidic mother liquor after extraction, until the water content is 1% to 90%, then mixing 1 to 20 times of the total amount of the mother liquor with a polar protic solvent, which is methanol or ethanol, so that the inorganic ammonium salt in the mother liquor is precipitated, and the salt of the aromatic amine compound and the acidic catalyst which is not hydrolyzed or is incompletely hydrolyzed and the excess acidic catalyst are dissolved in the polar protic solvent, separating the inorganic ammonium salt precipitate, and further distilling and removing the polar protic solvent, and the salt of the aromatic amine compound which is not hydrolyzed or is incompletely hydrolyzed and the excess acidic catalyst are used for the synthesis of the next batch, and the hydrolysis reaction is continued.

2. The method according to claim 1, wherein the method is characterized by, The phenolic compounds produced by the method are selected from the group consisting of p-methylphenol, m-methylphenol, 2-naphthol, 1-naphthol, m-hydroxybenzoic acid, 3,5-dimethylphenol, p-phenylphenol, p-benzene diol, m-benzene diol, 2,4-dihydroxytoluene (4-methyl m-benzene diol), 2,6-dihydroxytoluene (2-methyl m-benzene diol), m-trihydroxybenzene, 1,5-dihydroxynaphthalene, 3,5-dihydroxybenzoic acid, 2,5-dimethylphenol, 3,4-dimethylphenol, 8-hydroxyquinoline, 4-hydroxydiphenylamine, and a mixture of two or more of them.

3. The method according to claim 1, wherein the method is characterized by, The acidic catalyst used in the hydrolysis reaction is selected from the group consisting of sulfuric acid, ammonium bisulfate, phosphoric acid, hydrochloric acid, and hydrobromic acid.

4. The efficient and clean production method of phenolic compounds according to claim 1 or 3, characterized in that, The effective acidic group in the acidic catalyst aqueous solution is 1 to 20 times the molar amount of the amino group in the aromatic amine compound.

5. The method according to claim 1, wherein the method is characterized by, The water content of the mother liquor after the residual extraction solvent and part of the water are evaporated is controlled to be 30% to 60%.

6. The method according to claim 1, wherein the method is characterized by, The amount of the polar protic solvent added is 2 to 8 times the total amount of the mother liquor.

Images