A method for treating residual hydrogen peroxide in phenol hydroxylation reaction liquid

Abstract

The present invention provides a method for treating residual hydrogen peroxide in a phenol hydroxylation reaction liquid, wherein phenol and hydrogen peroxide react under the action of a catalyst to generate a phenol hydroxylation reaction liquid containing water, phenol, hydroquinone, tar, a small amount of hydrogen peroxide and quinone substances, a compound as shown in formula II is added to the phenol hydroxylation reaction liquid, and the reaction is carried out at 60-80° C. for 0.5-1 h. The treatment method of the present invention utilizes the characteristics of reducibility, water solubility and high boiling point of the compound shown in formula II, avoids decomposition and oxygen production during the treatment process, has no risk of combustion and explosion, and meets the requirements of intrinsic safety.

Description

Technical Field

[0001] The invention relates to the technical field of a method for preparing hydroquinone, and in particular to a method for treating residual hydrogen peroxide in a phenol hydroxylation reaction liquid. Background Art

[0002] Catechol and hydroquinone are two important intermediates with a wide range of applications. Catechol can be used to synthesize vanillin, (neo)heliotropin and other fragrances and pharmaceutical products, while hydroquinone can be used as an inhibitor, rubber antioxidant and antioxidant. Most of the catechol and hydroquinone currently available on the market are produced by the co-production of phenol and hydrogen peroxide hydroxylation reaction, mainly UBE method, Rhone-Poulenc method, Brichima method and Enichem method. Among them, Japan's UBE process uses sulfuric acid as a catalyst and has high requirements on equipment materials; France's Rhone Poulenc process uses HClO4 / H3PO4 as a catalyst, and the single-pass conversion rate of phenol is relatively low, only 5%; the Brichima process uses an iron-based catalyst and has a greater safety risk; Italy's Enichem process has replaced the Brichima process and is the current mainstream production process. It uses titanium silicalite (TS-1) as a catalyst and uses 27.5% hydrogen peroxide and phenol to react to produce o- / hydroquinone. The reaction conditions are mild and the selectivity of hydroquinone is greater than 90%.

[0003] The hydroxylation reaction of phenol and hydrogen peroxide has a significant tailing effect, that is, the lower the concentration of hydrogen peroxide, the slower the reaction rate, and it is difficult for hydrogen peroxide to be completely consumed. Therefore, the conversion rate of hydrogen peroxide in the normal reaction process is usually maintained between 97-99%, so that the hydroxylation reaction liquid contains 500-2000ppm of hydrogen peroxide. If the reaction liquid containing 500-2000ppm of hydrogen peroxide enters the subsequent distillation system without treatment, it will bring the following two risks: 1) Due to the high boiling point of hydrogen peroxide, it is easy to accumulate in the tower bottom and other locations with higher temperatures, and it is easy to form organic peroxides when heated for a long time. During the heating process, hydrogen peroxide will decompose to produce oxygen, and oxygen will form an explosive mixture with organic solvents such as acetone or methanol in the reaction liquid. It is very easy to explode when encountering open flames or static electricity; 2) Quinone substances such as p-benzoquinone and o-benzoquinone will exist in the hydroxylation reaction liquid. These substances are easy to further react with residual hydrogen peroxide to form tar, which will cause trouble for subsequent separation.

[0004] In order to consume the low concentration of hydrogen peroxide in the reaction solution, patent CN114225933B discloses a manganese oxide catalyst for decomposing hydrogen peroxide and a preparation method thereof. A mixed solution of a metal salt and a manganese salt is mixed with citric acid and gel in succession, and then heated to obtain a manganese oxide catalyst. The decomposition and removal rate of hydrogen peroxide with an initial concentration of 1000 ppm in water is close to 100% within 15 minutes. Suzan A et al. (Suzan A. Ali, J. Mater. Sci. Technol, Vol. 20, No. 1, 2004, 55-58) developed a new alumina-supported cobalt oxide-copper oxide catalyst and used it to decompose hydrogen peroxide. The initial hydrogen peroxide concentration was 0.73%. Under normal pressure and 30°C, hydrogen peroxide could be completely decomposed within 2 hours. Patent CN106140148B discloses a hydrogen peroxide decomposition catalyst, which is composed of a mixture of metal oxides of Group IVB, Group VIB, Group IB and Group IIIA. The catalyst is applied to the reaction liquid of epoxidation of 3-chloropropylene and hydrogen peroxide. At 35°C and within 30 minutes, the concentration of hydrogen peroxide in the epoxidation reaction liquid is reduced from 0.508% to 0.021%.

[0005] The above patented technology uses the strategy of decomposing residual hydrogen peroxide, but the decomposition of hydrogen peroxide will generate oxygen, which can easily form an explosive mixture with flammable liquids. Methanol or acetone is often used as a solvent in the hydroxylation reaction liquid of phenol and hydrogen peroxide, both of which are Class A liquids with a relatively wide explosion limit. Once they encounter oxygen, there are great safety hazards. Summary of the invention

[0006] In order to overcome the two problems of residual hydrogen peroxide in the prior art phenol hydroxylation reaction that is prone to decomposition and oxygen production and tar generation, the present invention provides a method for treating residual hydrogen peroxide in phenol hydroxylation reaction liquid, thereby preventing the residual peroxide from directly entering the distillation system and affecting subsequent products.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for treating residual hydrogen peroxide in a phenol hydroxylation reaction liquid. Phenol and hydrogen peroxide react under the action of a catalyst to generate a phenol hydroxylation reaction liquid containing water, phenol, hydroquinone, tar, a small amount of hydrogen peroxide and quinone substances. A compound as shown in formula II is added to the phenol hydroxylation reaction liquid, and the reaction is carried out at 60-80° C. for 0.5-1 h.

[0009] Formula II

[0010] Wherein, R is selected from H or CH3, C2H5.

[0011] The phenol hydroxylation reaction liquid mentioned in the treatment method of the present invention is aimed at the reaction liquid produced by preparing diphenol using the existing technology. In some specific embodiments, the composition of the phenol hydroxylation reaction liquid is as follows: 10-20% water, 25-35% phenol, 30-45% methanol, 15-20% diphenol, 1-5% tar, 0.05-0.2% hydrogen peroxide, 0.005-0.015% quinone substances. In some more specific embodiments, TS-1 can be used as a catalyst, phenol and hydrogen peroxide as reaction raw materials, methanol as a reaction solvent, and the reaction is carried out at a reaction temperature of about 60°C for about 1.5 hours.

[0012] In some specific embodiments, the mass ratio of the phenol hydroxylation reaction solution to the compound represented by the above formula II is (100-200):1, for example, 110, 160, 170, 180, 190; preferably (120-150):1, for example, 125:1, 130:1, 135:1, 140:1, 145:1.

[0013] The treatment method of the present invention utilizes the reducing property of the compound shown in the formula II to effectively consume the water generated by the hydrogen peroxide reaction in the phenol hydroxylation reaction liquid, avoids decomposition and oxygen production, has no risk of explosion, and meets the requirements of intrinsic safety; at the same time, utilizing its reducing properties, the phosphite and the hydroxylation reaction liquid can also react with the benzoquinone in the reaction liquid to generate hydroquinone, which can convert tar into products and turn waste into treasure. The sulfonic acid group in the compound shown in the formula II used has a certain water solubility, can be dissolved in the phenol hydroxylation reaction liquid, can react homogeneously with hydrogen peroxide, benzoquinone, etc., and improve the reaction efficiency. The high boiling point of the compound shown in the formula II makes it always in the tower bottom during the distillation process, and finally sent to incineration together with the tar, avoiding interference with product separation.

[0014] In the present invention, the preparation method of the compound represented by the above formula II can be selected from the following methods, including:

[0015] (1) reacting 1-naphthol or its derivatives as shown in the following formula I with concentrated sulfuric acid to obtain 1-naphtholsulfonic acid or its derivatives;

[0016] (2) reacting phosphorus trichloride, 1-naphtholsulfonic acid or its derivatives with triethylamine under low temperature conditions to obtain the compound represented by formula II;

[0017] Formula I

[0018] Formula II

[0019] In formula I and formula II, R is selected from H or CH3, C2H5.

[0020] Specifically, the synthesis route of the compound represented by the above formula II is as follows:

[0021] In a specific embodiment of the above preparation method, in step (1), the weight ratio of 1-naphthol or its derivative to concentrated sulfuric acid is 1:(2-3), for example, 1:2.2, 1:2.5, 1:2.8; and the reaction time is 3-5 h, for example, 3.5 h, 4 h, 4.5 h.

[0022] In some specific embodiments, the 1-naphthol or its derivative is dissolved in a solvent and then reacted with concentrated sulfuric acid. The solvent may be selected from N,N-dimethylformamide, DMSO, acetonitrile or water.

[0023] In some specific embodiments, in step (2), 1-naphtholsulfonic acid or its derivative and phosphorus trichloride are dissolved in a solvent to form a mixed solution, and triethylamine is then added dropwise to the mixed solution to react at low temperature; specifically, the solvent can be toluene, tetrahydrofuran, anisole or dichloromethane; in some preferred embodiments, the reaction is carried out at -20 to 0°C for 20 to 30 h; in some more preferred embodiments, after the reaction is completed, water is added to the reaction solution to quench the reaction, and the upper oil phase is washed with deionized water and separated to obtain the compound represented by formula II.

[0024] In a specific embodiment of the method for preparing the compound represented by formula II, in step (2), the mass ratio of 1-naphtholsulfonic acid or its derivative to phosphorus trichloride is controlled to be (1-3):1, for example, 1.5:1, 2.0:1, 2.5:1.

[0025] In some specific embodiments, the mass ratio of 1-naphtholsulfonic acid or its derivatives to triethylamine is controlled to be (1.0~1.5):1, for example, 1.2:1, 1.3:1.

[0026] In some specific embodiments, the temperature of the low-temperature reaction in step (2) is controlled at -20~0°C, for example, -15°C, -10°C, -5°C; and the reaction time is 20~30 h, for example, 25 h, 28 h.

[0027] In some specific embodiments, the phenol hydroxylation reaction liquid reacts with the compound shown in Formula II in an aging reactor; wherein the aging reactor is selected from a reactor, a fixed bed, a tower reactor, a fluidized bed or a storage tank. Specifically, the present invention sets an aging reactor after the hydroxylation reactor and sets a certain residence time to play a buffering role for the subsequent distillation system, thereby preventing excessive residual peroxide from directly entering the distillation system.

[0028] In some specific embodiments, after being treated by the treatment method of the present invention, the concentration of hydrogen peroxide at the outlet of the aging reactor is less than 10 ppm, and the concentration of benzoquinone is less than 5 ppm.

[0029] The above technical solution has the following technical effects:

[0030] The treatment method of the present invention utilizes the characteristics of reducibility, water solubility and high boiling point of the compound shown in formula II, avoids decomposition and oxygen production during the treatment process, has no risk of explosion, and meets the requirements of intrinsic safety. At the same time, the compound shown in formula II has a sulfonic acid group, has a certain water solubility, can be dissolved in the phenol hydroxylation reaction solution, and reacts homogeneously with hydrogen peroxide, p-benzoquinone, etc., to improve the reaction efficiency.

[0031] The treatment method of the present invention uses an aging reactor to be arranged behind the hydroxylation reactor, and sets a certain residence time, so as to play a buffering role for the subsequent distillation system and prevent excessive residual peroxide from directly entering the distillation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : NMR spectrum of the compound represented by formula II prepared in Example 1 of the present invention;

[0033] Figure 2 : The NMR spectrum of the compound represented by Formula II prepared in Example 2 of the present invention;

[0034] Figure 3 : NMR spectrum of the compound shown in Formula II prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0036] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0037] Example 1

[0038] (1) Inject 30 g of 1-naphthol and 150 g of DMF into a three-necked flask, slowly drop 60 g of concentrated sulfuric acid (mass concentration 98%) into the reaction system at room temperature, react for 3 h, and separate and purify to obtain the compound 1-naphthol sulfonic acid;

[0039] (2) Under anhydrous conditions, 30 g of the above-prepared 1-naphtholsulfonic acid and 20 g of phosphorus trichloride were dissolved in 150 g of toluene and injected into a three-necked flask. The three-necked flask was cooled to -15°C, and 30 g of triethylamine was added dropwise to the three-necked flask. After the addition was completed, the reaction was continued for 30 hours, and then 20 g of water was added to quench the reaction. The upper oil phase was taken, washed with deionized water, and separated to obtain the compound shown in the following formula II:

[0040] Formula II

[0041] The compound of formula II prepared by this method was subjected to nuclear magnetic resonance analysis, and the analysis results of hydrogen spectrum were as follows: 2.0 (2H), 7.58 (2H), 7.61 (2H), 7.69 (2H), 8.00 (2H), 8.09 (2H); the specific spectrum is shown in Figure 1 shown.

[0042] 20 g of the compound of formula II prepared above and 2000 g of phenol hydroxylation reaction liquid were reacted in a reactor, wherein the composition of the phenol hydroxylation reaction liquid was: 18% water, 27% phenol, 35% methanol, 17.2% hydroquinone, 2.7% tar, 0.09% hydrogen peroxide, and 0.01% quinone substances; the reaction liquid was reacted at 80°C for 0.5h, and the concentration of hydrogen peroxide at the discharge port of the reactor dropped to below 10ppm, and the concentration of p-benzoquinone dropped to below 5ppm.

[0043] Example 2

[0044] (1) Inject 30 g of 7-methyl-1-naphthol and 160 g of DMSO into a three-necked flask, slowly drop 66 g of concentrated sulfuric acid (mass concentration: 98%) into the reaction system at room temperature, react for 3.5 h, and separate and purify to obtain the compound 7-methyl-1-naphtholsulfonic acid;

[0045] (2) Under anhydrous conditions, 30 g of the above-prepared 7-methyl-1-naphtholsulfonic acid and 15 g of phosphorus trichloride were dissolved in 140 g of toluene and injected into a three-necked flask. The three-necked flask was cooled to -10°C, and 22 g of triethylamine was added dropwise to the three-necked flask. After the addition was completed, the reaction was continued for 25 hours, and then 20 g of water was added to quench the reaction. The upper oil phase was taken, washed with deionized water, and separated to obtain the compound shown in the following formula II:

[0046] Formula II

[0047] The compound of formula II prepared by this method was subjected to nuclear magnetic resonance analysis, and the analysis results of hydrogen spectrum were as follows: 2.0 (2H), 2.45 (6H), 7.11 (2H), 7.65 (2H), 8.01 (2H), 8.03 (2H), 8.40 (2H); the specific spectrum is as follows Figure 2 shown.

[0048] 20 g of the compound of formula II prepared above and 3000 g of phenol hydroxylation reaction liquid were reacted in a reactor, wherein the composition of the phenol hydroxylation reaction liquid was: 16% water, 30% phenol, 32% methanol, 18.9% hydroquinone, 2.969% tar, 0.12% hydrogen peroxide, and 0.011% quinone substances; the reaction liquid was reacted at 80°C for 0.5h, and the concentration of hydrogen peroxide at the discharge port of the reactor dropped to below 5ppm, and the concentration of p-benzoquinone dropped to below 3ppm.

[0049] Example 3

[0050] (1) Inject 30 g of 7-ethyl-1-naphthol and 165 g of acetonitrile into a three-necked flask, slowly drop 75 g of concentrated sulfuric acid (mass concentration: 98%) into the reaction system at room temperature, react for 4 h, and separate and purify to obtain the compound 7-ethyl-1-naphtholsulfonic acid;

[0051] (2) Under anhydrous conditions, 30 g of the above-prepared 7-ethyl-1-naphtholsulfonic acid and 12 g of phosphorus trichloride were dissolved in 140 g of tetrahydrofuran and injected into a three-necked flask. The three-necked flask was cooled to -5°C, and 24 g of triethylamine was added dropwise to the three-necked flask. After the addition was completed, the reaction was continued for 28 hours, and then 20 g of water was added to quench the reaction. The upper oil phase was taken, washed with deionized water, and separated to obtain the compound shown in the following formula II:

[0052] Formula II

[0053] The compound of formula II prepared by this method was subjected to nuclear magnetic resonance analysis, and the hydrogen spectrum analysis results were as follows: 1.31 (6H), 2.71 (4H), 7.11 (2H), 7.65 (2H), 8.01 (2H), 8.03 (2H), 8.40 (2H); the specific spectrum is shown in Figure 3 shown.

[0054] 20 g of the compound of formula II prepared above and 2000 g of phenol hydroxylation reaction liquid were reacted in a reactor, wherein the composition of the phenol hydroxylation reaction liquid was: 19% water, 33% phenol, 31% methanol, 15.5% hydroquinone, 1.4% tar, 0.09% hydrogen peroxide, and 0.01% quinone substances; the reaction liquid was reacted at 80°C for 0.5h, and the concentration of hydrogen peroxide at the discharge port of the reactor dropped to below 6ppm, and the concentration of p-benzoquinone dropped to below 4ppm.

[0055] Example 4

[0056] (1) Pour 30 g of 1-naphthol and 170 g of water into a three-necked flask, slowly drop 80 g of concentrated sulfuric acid (mass concentration 98%) into the reaction system at room temperature, react for 3.8 h, and separate and purify to obtain the compound 1-naphthol sulfonic acid;

[0057] (2) Under anhydrous conditions, 30 g of the above-prepared 1-naphtholsulfonic acid and 26 g of phosphorus trichloride were dissolved in 130 g of anisole, and the mixture was poured into a three-necked flask. The three-necked flask was cooled to 0°C, and 20 g of triethylamine was added dropwise to the three-necked flask. After the addition was completed, the reaction was continued for 22 hours, and then 20 g of water was added to quench the reaction. The upper oil phase was taken, washed with deionized water, and separated to obtain the compound shown in the following formula II:

[0058] Formula II

[0059] The compound of formula II prepared by this method was subjected to nuclear magnetic resonance analysis. The results of hydrogen spectrum analysis were as follows: 2.0 (2H), 7.58 (2H), 7.61 (2H), 7.69 (2H), 8.00 (2H), 8.09 (2H). Its nuclear magnetic spectrum was the same as that in Example 1 and is not provided again.

[0060] 20 g of the compound of formula II prepared above and 3900 g of phenol hydroxylation reaction liquid were reacted in a reactor, wherein the composition of the phenol hydroxylation reaction liquid was: 15% water, 33% phenol, 30% methanol, 18% hydroquinone, 3.851% tar, 0.14% hydrogen peroxide, and 0.009% quinone substances; the reaction liquid was reacted at 80°C for 0.5h, and the concentration of hydrogen peroxide at the discharge port of the reactor dropped to below 8ppm, and the concentration of p-benzoquinone dropped to below 3ppm.

[0061] Comparative Example 1

[0062] 2000g of phenol hydroxylation reaction liquid is subjected to aging reaction in a reactor, wherein the composition of the phenol hydroxylation reaction liquid is: 15% water, 33% phenol, 30% methanol, 18% hydroquinone, 3.851% tar, 0.14% hydrogen peroxide, and 0.009% quinone substances; the reaction liquid is reacted at 80°C for 3h, and the hydrogen peroxide concentration at the discharge port of the reactor is reduced to 500ppm and the concentration of p-benzoquinone is about 80ppm. After entering the distillation, nitrogen needs to be continuously introduced to avoid the decomposition of hydrogen peroxide to produce oxygen and form an explosive mixture.

[0063] Comparative Example 2

[0064] The compound shown in the following formula II was prepared in the manner of Example 4;

[0065] Formula II

[0066] The compound of formula II prepared by this method was subjected to nuclear magnetic resonance analysis, and the results of hydrogen spectrum analysis were as follows: 2.0 (2H), 7.58 (2H), 7.61 (2H), 7.69 (2H), 8.00 (2H), 8.09 (2H); its nuclear magnetic spectrum was the same as that in Example 1 and is not provided again.

[0067] 20 g of the compound of formula II prepared above and 200,000 g of phenol hydroxylation reaction liquid are taken into a reactor for aging reaction, wherein the composition of the phenol hydroxylation reaction liquid is: 19% water, 33% phenol, 31% methanol, 15.5% hydroquinone, 1.4% tar, 0.09% hydrogen peroxide, and 0.01% quinone substances; the reaction liquid is reacted at 80°C for 3 hours, and the hydrogen peroxide concentration at the discharge port of the reactor is reduced to 200 ppm and the concentration of p-benzoquinone is about 50 ppm. After entering the distillation, nitrogen needs to be continuously introduced to avoid the decomposition of hydrogen peroxide to produce oxygen and form an explosive mixture.

Claims

1. A method for treating residual hydrogen peroxide in a phenol hydroxylation reaction solution, characterized in that: Phenol and hydrogen peroxide react under the action of a catalyst to generate a phenol hydroxylation reaction liquid containing water, phenol, hydroquinone, tar, a small amount of hydrogen peroxide and quinone substances, and a compound as shown in formula II is added to the phenol hydroxylation reaction liquid, and the reaction is carried out at 60-80° C. for 0.5-1 h; Formula II Wherein, R is selected from H or CH3, C2H5.

2. The processing method according to claim 1, characterized in that: The composition of the phenol hydroxylation reaction solution is as follows: 10-20% water, 25-35% phenol, 30-45% methanol, 15-20% hydroquinone, 1-5% tar, 0.05-0.2% hydrogen peroxide, and 0.005-0.015% quinone substances.

3. The processing method according to claim 2, characterized in that: The mass ratio of the phenol hydroxylation reaction liquid to the compound represented by formula II is (100-200):

1.

4. The processing method according to any one of claims 1 to 3, characterized in that: The preparation method of the compound represented by formula II comprises: (1) reacting 1-naphthol or its derivatives as shown in the following formula I with concentrated sulfuric acid to obtain 1-naphtholsulfonic acid or its derivatives; (2) reacting phosphorus trichloride, 1-naphtholsulfonic acid or its derivatives with triethylamine at -20 to 0°C to obtain the compound represented by formula II; Formula I In formula I, R is selected from H or CH3, C2H5.

5. The processing method according to claim 4, characterized in that In step (1), the weight ratio of 1-naphthol or its derivatives to concentrated sulfuric acid is 1:(2-3), and the reaction time is 3-5 h.

6. The processing method according to claim 5, characterized in that: The 1-naphthol or its derivative is dissolved in a solvent and reacted with concentrated sulfuric acid; Wherein, the solvent is selected from N,N-dimethylformamide, DMSO, acetonitrile or water.

7. The processing method according to claim 4, characterized in that: In step (2), 1-naphtholsulfonic acid or its derivative and phosphorus trichloride are dissolved in a solvent to form a mixed solution, and triethylamine is added dropwise to the mixed solution to react at a low temperature; The reaction is carried out at -20~0°C and the reaction time is 20~30 h; After the reaction is completed, water is added to the reaction solution to quench it, and then the upper oil phase is washed with deionized water and separated to obtain the compound represented by the formula II.

8. The processing method according to claim 7, characterized in that The mass ratio of 1-naphtholsulfonic acid or its derivative to phosphorus trichloride is controlled to be (1-3):1, The mass ratio of the 1-naphtholsulfonic acid or its derivatives to triethylamine is controlled to be (1.0-1.5):

1.

9. The processing method according to any one of claims 1 to 3 and 5 to 8, characterized in that: The phenol hydroxylation reaction liquid reacts with the compound represented by formula II in an aging reactor; The aging reactor is selected from a reactor, a fixed bed, a tower reactor, a fluidized bed or a storage tank.

10. The processing method according to claim 9, characterized in that The concentration of hydrogen peroxide at the outlet of the aging reactor is less than 10 ppm, and the concentration of benzoquinone is less than 5 ppm.

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