Environmentally-friendly method for co-producing benzoquinone compound and hydroquinone

Abstract

Disclosed in the present invention is an environmentally-friendly method for co-producing a benzoquinone compound and hydroquinone. The method comprises subjecting a phenolic compound and benzoquinone to an oxidation-reduction reaction in a protonic acid catalyst and a solvent to generate a benzoquinone compound and hydroquinone, wherein the solvent comprises at least one of water or an alcohol solvent. In the method, trimethylbenzoquinone production, which originally requires oxidation by means of an oxidizing agent, is coupled with hydroquinone production, which requires reduction by means of hydrogen, and an inexpensive acid (I) is used as a catalyst to perform an oxidation-reduction reaction; and two important chemical products are obtained at the same time, the catalytic efficiency is high, and the co-production yield is high. Therefore, the method is beneficial for lowering the production costs of trimethylbenzoquinone and hydroquinone, and reducing environmental pollution.

Description

Green co-production method of benzoquinone compound and hydroquinone TECHNICAL FIELD

[0001] The present application relates to the technical field of fine chemical synthesis, in particular to a green co-production method of benzoquinone compound and hydroquinone. BACKGROUND

[0002] Vitamin E is the general term for tocopherols, which has been highly concerned since its discovery in 1922. Nowadays, vitamin E is very important in the field of health care products, and also has important uses in the fields of medicine, food, feed, cosmetics and so on. An important intermediate for the synthesis of vitamin E is 2,3,5-trimethylhydroquinone 2,3,5-trimethylhydroquinone can be obtained by catalytic hydrogenation of trimethylbenzoquinone. Trimethylbenzoquinone, i.e. 2,3,5-trimethylbenzoquinone (abbreviated as TMBQ), is also an important pharmaceutical intermediate. The main raw materials for the synthesis of TMBQ are 2,3,5-trimethylphenol, 2,3,6-trimethylphenol and pseudocumene. At present, 2,3,6-trimethylphenol is mainly selected as the raw material for the synthesis of TMBQ.

[0003] According to the synthesis of TMBQ from 2,3,6-trimethylphenol, there are chemical oxidation method and catalytic oxidation method. In the chemical oxidation method, 2,3,6-trimethylphenol is subjected to sulfonation to obtain 4-sulfonic acid group-2,3,6-trimethylphenol, which is then oxidized by manganese dioxide to obtain TMBQ. This method has the advantages of simple synthesis and low equipment investment cost, but has the disadvantages of easy environmental pollution and the fact that 4-sulfonic acid group-2,3,6-trimethylphenol is easy to caking, which makes the dissolution operation cumbersome.

[0004] In the catalytic oxidation method, hydrogen peroxide (H2O2) is used as the oxygen source, and then TMBQ is obtained by dehydration. In laboratory research, the effects of various catalysts have been reported, and ruthenium-based catalysts The yield of trimethylbenzoquinone 83% can be achieved (Adv. Synth. Catal, DOI: 10.1002 / adsc.201000137); furthermore, using CuCl2-poly(4-vinylpyridine) as a catalyst, using DMSO as a solvent, and using oxygen as an oxygen source, the conversion rate of 2,3,6-trimethylphenol can reach 100%, and the selectivity can reach 95%. Chinese patent CN96180478.5 discloses a method for obtaining TMBQ by oxidizing 2,3,6-trimethylphenol using a heteropoly acid catalytic system, which can obtain a TMBQ yield of 95% and a 2,3,6-trimethylphenol conversion rate of 100%; Chinese patent CN201711037289.4 proposes a process for synthesizing using paratetramethylbenzene as a raw material, reducing the generation of by-products, and improving the yield of trimethylbenzoquinone. These catalytic oxidation methods use oxygen or hydrogen peroxide as an oxidant, which is relatively environmentally friendly, but the disadvantages are that the selectivity is difficult to control, the oxygen pressure required is high, the cost of high-pressure reaction equipment is high, and the metal catalyst used is relatively expensive.

[0005] Hydroquinone is another widely used chemical product. As of 2018, the global demand for hydroquinone was approximately 70,000 tons, mainly imported from France, Italy, the United States, and other countries. The demand for hydroquinone is gradually increasing. Hydroquinone, also known as p-dihydroxybenzene, is mainly used for the synthesis of hydrogen peroxide, and is also used for the synthesis of intermediates such as photographic film, polymerization inhibitors, berberine, and adrenaline. There are more than ten synthesis technologies for hydroquinone, and the main process routes include the Reppe synthesis method, which uses acetylene and carbon monoxide as raw materials to react under high temperature and high pressure, requiring expensive catalysts and being difficult to recover; the aniline oxidation method, which uses aniline as a raw material and manganese dioxide as an oxidant under acidic conditions, causing equipment corrosion; in addition, there are p-diisopropylbenzene peroxidation method, bisphenol A method, phenol peroxide hydrogenation method, and electrochemical method, etc. In the synthesis process of hydroquinone, p-benzoquinone is often first generated by oxidizing phenol, aniline, etc. The reason is that hydroquinone is easily oxidized and is easily further oxidized to p-benzoquinone, so a reducing agent such as hydrogen is needed to reduce p-benzoquinone to obtain hydroquinone. Therefore, the method of industrial production of hydroquinone wastes oxidants and hydrogen, lacking atom economy. SUMMARY

[0006] The purpose of the present application is to provide a green co-production method of benzoquinone compounds and hydroquinone, which can simultaneously achieve efficient preparation of benzoquinone compounds and hydroquinone, and does not need to add additional oxidants and reducing agents.

[0007] To achieve the above purpose, the technical scheme adopted by the present application is:

[0008] A preparation method of co-producing benzoquinone compounds and hydroquinone, the method comprising: a phenolic compound represented by formula (a) and benzoquinone are subjected to redox reaction in a protic acid catalyst and a solvent to generate a benzoquinone compound represented by formula (b) and hydroquinone, the reaction formula is:

[0009] wherein R1, R2, R3, R4 are independently selected from H, C 1-10 alkyl, C 1-10 alkoxy, Cl, F, Br, I, C6-C 10 aryl, or R1, R2 form a ring with the carbon chain connecting R1, R2;

[0010] The solvent at least contains one of water or alcohol solvent.

[0011] wherein the C6-C 10 aryl is further preferably phenyl or naphthyl; the C 1-10 alkyl is further preferably C 1-6 alkyl, the C 1-10 alkoxy is further preferably C 1-6 alkoxy.

[0012] wherein "at least contains" means that the solvent can also contain other solvents or not contain other solvents, the alcohol solvent is further selected from one or more of methanol, ethanol, n-butanol, t-butyl alcohol, isobutyl alcohol, n-propanol, isopropanol, amyl alcohol, ethylene glycol, 1-hexanol or hexafluoroisopropyl alcohol; the other solvents are further selected from a combination of one or more of acetonitrile, acetone, toluene, tetrahydrofuran, n-hexane, N,N-dimethylformamide, N,N-dimethylacetamide, 1-ethyl-3-methylimidazole acetate, 1-ethylimidazole, diethylene glycol dimethyl ether, ethylene glycol methyl ether. And further, the other solvents should not contain oxidizing solvents, such as dimethyl sulfoxide.

[0013] The application innovatively combines two industrial conversion processes of preparing quinone compounds and hydroquinone, without adding other oxidants and reducing agents, to realize the co-production of quinone compounds and hydroquinone, while the method uses cheap protic acid as catalyst, has high catalytic efficiency, high conversion rate and good selectivity, and is conducive to improving the competitiveness of quinone compound and hydroquinone synthesis. Taking quinone compound TMBQ as an example, the key of the method is to activate p-benzoquinone to water or alcohol solvent, so that the oxygen in the water or alcohol solvent molecules is used for oxygenation reaction to generate TMBQ. Theoretically, one part of 2,3,6-trimethylphenol reacts with two parts of p-benzoquinone and one part of water to generate one part of TMBQ and two parts of hydroquinone. The protic acid used as catalyst in the method can activate benzoquinone, increase the activity of activated water or alcohol solvent, avoid the use of metal catalyst, be environmentally friendly, low in cost, and the reaction has high atom economy.

[0014] As a preference, the redox reaction is carried out under an atmosphere of one or more mixed gases of air, nitrogen, argon, oxygen, preferably a nitrogen atmosphere.

[0015] As a preference, R1, R2, R3, R4 in formula (a) are each independently selected from H, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-pentyl, isopentyl, neopentyl, hexyl, methoxy, ethoxy, isopropoxy, t-butoxy, Cl, F, Br, I, phenyl, or R1, R2 and the carbon chain connecting R1, R2 form a five-membered ring or a six-membered ring, which can be an aliphatic ring or an aromatic ring.

[0016] As a preference, the molar ratio of the phenolic compound to the p-benzoquinone is 1:0.05-15. Further, the molar ratio of the phenolic compound to the p-benzoquinone is 1:1-8. Further, the molar ratio of the phenolic compound to the p-benzoquinone is 1:2-6.

[0017] As a preference, the reaction temperature of the redox reaction is 20-160°C, preferably 50-90°C.

[0018] As a preference, when the solvent condition is an aqueous solvent condition, the mass ratio of the non-aqueous solvent to the water in the solvent is 1:0-15, and does not include 0. Further, the mass ratio of the non-aqueous solvent to the water is 1:0.1-10; further, the mass ratio of the non-aqueous solvent to the water is 1:0.1-8. Further, the solvent is a binary mixed solvent of methanol / water, ethanol / water, t-butanol / water, n-butanol / water, 1-butanol / water, acetonitrile / water, isopropyl alcohol / water, 1-hexanol / water, dimethylacetamide / water, tetrahydrofuran / water, hexafluoroisopropyl alcohol / water, n-hexane / water, acetone / water, ethyleneglycol dimethyl ether / water, ethyleneglycol methyl ether / water.

[0019] The amount of the mixed solvent is not particularly strictly required, and can be sufficient to dissolve the reaction raw materials, and is generally about 2-6 g of the total amount of the solvent used for 1 mmol of the phenolic compound.

[0020] As a preference, the reaction is carried out under a pressure of 0.1-1 MPa.

[0021] As a preference, the reaction time of the redox reaction is 0.5-96 h.

[0022] As preferred, the phenolic compound represented by formula (a) is one or more selected from the group consisting of 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, o-cresol, m-cresol, 2,6-dimethylphenol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,5-dimethylphenol, thymol, 5-isopropyl-2-methylphenol, 5-isopropoxy-2-methylphenol, 2-methyl-1-naphthol, 2,3,5,6-tetramethylphenol, 2-methyl-5-chlorophenol, 2-chloro-3,5-dimethylphenol, 3-bromo-2,5-dimethylphenol, 2,6-dimethoxyphenol, 3-methoxyphenol, 2,3-dihydro-1H-4-indenol, 2,4-dimethyl-[1,1'-biphenyl]-3-ol, 4-methyl-[1,1'-biphenyl]-3-ol, 3,5-dimethyl-2-methoxyphenol, 3,5-dimethyl-2-iodophenol.

[0023] As preferred, the protonic acid catalyst is selected from one or more selected from the group consisting of methanesulfonic acid, trifluoromethanesulfonic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, benzoic acid, nitric acid, acetic acid, trifluoroacetic acid, nitric acid, hydrobromic acid, phosphoric acid; further, the protonic acid catalyst is preferably one or more selected from the group consisting of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid, acetic acid, trifluoroacetic acid, hydrochloric acid. Further, the molar ratio of the protonic acid catalyst to the phenolic compound is 0 . 001~4:1, preferably 0 . 001~1:1, further preferably 0.05~0.2:1.

[0024] Compared with the prior art, the beneficial effects of the present application are embodied in:

[0025] The present application couples the production of trimethylbenzoquinone which originally needs to be oxidized by an oxidant and the production of hydroquinone which needs to be reduced by hydrogen, to carry out the redox reaction with a cheap acid as catalyst, while obtaining two important chemical products, with high catalytic efficiency and high co-production yield, which is conducive to reducing the production cost of trimethylbenzoquinone and hydroquinone and reducing environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the GC-MS result of 2,3,5-trimethylbenzoquinone in Example 3, in which the position of 2,3,5-trimethylbenzoquinone is marked and the accurate molecular weight is given;

[0027] Figures 2 and 3 are nuclear magnetic resonance spectra of 2,3,5-trimethylbenzoquinone and hydroquinone separated by column in Example 10, respectively.

[0028] Figure 4 is the QTOF result of the column separation product of TMBQ in Example 10;

[0029] Figure 5 is the QTOF result of the product of the column separation of hydroquinone in Example 10;

[0030] Figure 6 is the GC-MS result of 2,6-dimethyl-1,4-benzoquinone in Example 14, in which the position of 2,6-dimethyl-1,4-benzoquinone is marked;

[0031] Figure 7 is the GC-MS result of tetramethyl-1,4-benzoquinone in Example 19, in which the position of tetramethyl-1,4-benzoquinone is marked. DETAILED DESCRIPTION

[0032] The above scheme is further illustrated in combination with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present application, and the present application is not limited in scope by the following examples; the implementation conditions used in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0033] In the following examples, all raw materials are from commercial sources or prepared by conventional methods in the art, unless otherwise specified.

[0034] In the following examples, all reaction conversion rates and yields are determined by gas chromatography (using commercially purchased raw materials and products to establish standard curves).

[0035] Comparative Example 1

[0036] This comparative example provides a production process for co-producing TMBQ and hydroquinone, which adopts the following synthesis path:

[0037] The method includes the following steps: in a 20 mL reaction bottle, 0.5 mmol of 2,3,6-trimethylphenol, 1.5 mmol of 1,4-benzoquinone, 1.4 g of methanol, and 0.6 g of water are added, a magnetic stirrer is added, vacuum is applied and then a nitrogen gas bag is connected (0.1 MPa), and the reaction is carried out at 70°C for 24 hours. The conversion rate of 2,3,6-trimethylphenol is 100%, the selectivity of TMBQ is 70.9%, the conversion rate of 1,4-benzoquinone is 86.9%, and the selectivity of hydroquinone is 41.3%.

[0038] Example 1

[0039] This example provides a production process for co-producing TMBQ and hydroquinone, which adopts the following synthesis path:

[0040] The method comprises the following steps: in a 20 mL reaction bottle, 0.5 mmol of 2,3,6-trimethylphenol, 1.5 mmol of 1,4-p-benzoquinone, 1.4 g of methanol, 0.6 g of water, 0.1 mmol of hydrochloric acid solution (mass concentration 37 %) are added, a magnetic stirrer is added, vacuum is drawn and a nitrogen gas bag (0.1 MPa) is connected, and reaction is carried out at 70 °C for 2 hours, sampling is carried out, and gas chromatography analysis is carried out, and the results are as follows: the conversion rate of 2,3,6-trimethylphenol is 100 %, the selectivity of TMBQ is 97.5 %, the conversion rate of 1,4-p-benzoquinone is 83.7 %, and the selectivity of hydroquinone is 40.5 %.

[0041] Example 2

[0042] The embodiment provides a production process for co-production of TMBQ and hydroquinone, and the difference between the embodiment and the embodiment 1 is that 0.1 mmol of hydrochloric acid is replaced by 0.1 mmol of trifluoroacetic acid, and reaction is carried out. The analysis results are that the conversion rate of 2,3,6-trimethylphenol is 94.6 %, the selectivity of TMBQ is 96.0 %, the conversion rate of 1,4-p-benzoquinone is 77.8 %, and the selectivity of hydroquinone is 60.8 %.

[0043] Example 3

[0044] The embodiment provides a production process for co-production of TMBQ and hydroquinone, and the difference between the embodiment and the embodiment 1 is that 0.1 mmol of hydrochloric acid is replaced by 0.1 mmol of trifluoromethanesulfonic acid, and reaction is carried out. The analysis results are that the conversion rate of 2,3,6-trimethylphenol is 93.3 %, the selectivity of TMBQ is 100 %, the conversion rate of 1,4-p-benzoquinone is 75.8 %, and the selectivity of hydroquinone is 66.6 %, and the gas chromatogram is shown in Figure 1, wherein the TMBQ gas phase position is marked.

[0045] Example 4

[0046] The embodiment provides a production process for co-production of TMBQ and hydroquinone, and the difference between the embodiment and the embodiment 3 is that the molar amount of trifluoromethanesulfonic acid is 0.05 mmol, and reaction is carried out. The analysis results are that the conversion rate of 2,3,6-trimethylphenol is 93.2 %, the selectivity of TMBQ is 93.9 %, the conversion rate of 1,4-p-benzoquinone is 72.1 %, and the selectivity of hydroquinone is 65.8 %.

[0047] Example 5

[0048] This example provides a production process for co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction was carried out with 0.5 mmol of triflic acid. The analytical results were 95.0% conversion of 2,3,6-trimethylphenol, 100% selectivity for TMBQ, 91.7% conversion of 1,4-p-benzoquinone, and 44.9% selectivity for hydroquinone.

[0049] Example 6

[0050] This example provides a production process for co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction was carried out with 2 mmol of triflic acid. The analytical results were 89.6% conversion of 2,3,6-trimethylphenol, 70.8% selectivity for TMBQ, 66.4% conversion of 1,4-p-benzoquinone, and 79.2% selectivity for hydroquinone.

[0051] Example 7

[0052] This example provides a production process for co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction was carried out at 50°C. The analytical results were 87.3% conversion of 2,3,6-trimethylphenol, 93.2% selectivity for TMBQ, 69.6% conversion of 1,4-p-benzoquinone, and 79.2% selectivity for hydroquinone.

[0053] Example 8

[0054] This example provides a production process for co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the solvent conditions were changed to acetonitrile (1.4 g) and water (0.6 g). The analytical results were 82.1% conversion of 2,3,6-trimethylphenol, 79.3% selectivity for TMBQ, 61.9% conversion of 1,4-p-benzoquinone, and 78.2% selectivity for hydroquinone.

[0055] Example 9

[0056] This example provides a production process for co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction was carried out at 50°C for 6.5 hours. The analytical results were 93.3% conversion of 2,3,6-trimethylphenol, 83.5% selectivity for TMBQ, 67.6% conversion of 1,4-p-benzoquinone, and 88.2% selectivity for hydroquinone.

[0057] Example 10

[0058] The embodiment provides a production process for co-production of TMBQ and hydroquinone. Compared with the embodiment 3, the embodiment is different in that the molar amount of 2,3,6-trimethylphenol and 1,4-p-benzoquinone is amplified by 10 times, 1 mmol of trifluoromethanesulfonic acid, 14 g of methanol and 6 g of water are added, and reaction is performed for 24 hours. The conversion rate of 2,3,6-trimethylphenol is 100 %, the conversion rate of 1,4-p-benzoquinone is 82.1 %, the selectivity of TMBQ is 95.9 %, and the selectivity of hydroquinone is 77.7 % according to the gas phase detection. After appropriate silica gel is added and rotary drying is performed, column chromatography separation is performed to obtain two products. After drying, the products are respectively detected by mass spectrometry. The final yield of TMBQ is 93.1 %, and the yield of hydroquinone is 62.3 %. FIG. 2 and FIG. 3 are nuclear magnetic spectrum diagrams of TMBQ and hydroquinone obtained by column separation, and FIG. 4 and FIG. 5 are QTOF results of TMBQ and hydroquinone obtained by column separation.

[0059] Embodiment 11

[0060] The embodiment provides a production process for co-production of TMBQ and hydroquinone. Compared with the embodiment 3, the embodiment is different in that the solvent condition is changed into dimethyl sulfoxide (1.4 g) and water (0.6 g), and reaction is performed for 24 hours. The conversion rate of 2,3,6-trimethylphenol is 99.7 %, the selectivity of TMBQ is 25.7 %, the conversion rate of 1,4-p-benzoquinone is 97.7 %, and the selectivity of hydroquinone is 36.9 % according to the analysis result.

[0061] Embodiment 12

[0062] The embodiment provides a production process for co-production of TMBQ and hydroquinone. Compared with the embodiment 3, the embodiment is different in that the solvent type is changed into methanol and water, and reaction is performed for 24 hours under air condition. The conversion rate of 2,3,6-trimethylphenol is 100 %, the selectivity of TMBQ is 68.4 %, the conversion rate of 1,4-p-benzoquinone is 95.5 %, and the selectivity of hydroquinone is 42.4 %.

[0063] The results of the embodiment 11 and the embodiment 12 show that the reaction result is poor when the oxidative solvent dimethyl sulfoxide is used or the reaction atmosphere is air. It is considered that the oxidative environment may have adverse interference on the oxidation-reduction reaction.

[0064] Embodiment 13

[0065] The embodiment provides a production process for co-production of TMBQ and hydroquinone. Compared with the embodiment 3, the embodiment is different in that the solvent system is ethylene glycol monomethyl ether (1.4 g) and water (0.6 g), and reaction is performed for 24 hours. The conversion rate of 2,3,6-trimethylphenol is 98.6 %, the selectivity of TMBQ is 97.0 %, the conversion rate of 1,4-p-benzoquinone is 86.6 %, and the selectivity of hydroquinone is 71.3 % according to the analysis result.

[0066] Example 14

[0067] This example provides a production process for co-production of 2,6-dimethyl-1,4- benzoquinone and hydroquinone, which is different from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 2,6-dimethylphenol, and the reaction is carried out for 24 hours. The analysis results are that the conversion rate of 2,6-dimethylphenol is 80.7%, the selectivity of 2,6-dimethyl-1,4-benzoquinone is 46.1%, the conversion rate of 1,4-benzoquinone is 82.9%, and the selectivity of hydroquinone is 53.9%. The gas chromatogram is shown in FIG. 6, in which the gas phase position of 2,6-dimethyl-1,4-benzoquinone is marked.

[0068] Example 15

[0069] This example provides a production process for co-production of 2,5-dimethyl-1,4- benzoquinone and hydroquinone, which is different from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 2,5-dimethylphenol, and the reaction is carried out for 24 hours. The analysis results are that the conversion rate of 2,5-dimethylphenol is 96.4%, the selectivity of 2,5-dimethyl-1,4-benzoquinone is 80.2%, the conversion rate of 1,4-benzoquinone is 93.4%, and the selectivity of hydroquinone is 58.4%.

[0070] Example 16

[0071] This example provides a production process for co-production of thymoquinone and hydroquinone, which is different from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of thymol, and the reaction is carried out for 24 hours. The analysis results are that the conversion rate of thymol is 86.2%, the selectivity of thymoquinone is 48.9%, the conversion rate of 1,4-benzoquinone is 92.1%, and the selectivity of hydroquinone is 48.9%.

[0072] Example 17

[0073] This example provides a production process for co-production of 2,3-dimethyl-1,4- benzoquinone and hydroquinone, which is different from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 2,3-dimethylphenol, and the reaction is carried out for 24 hours. The analysis results are that the conversion rate of 2,3-dimethylphenol is 94.3%, the selectivity of 2,3-dimethyl-1,4-benzoquinone is 82.7%, the conversion rate of 1,4-benzoquinone is 90.4%, and the selectivity of hydroquinone is 49.0%.

[0074] Example 18

[0075] The present example provides a production process for co-production of thymoquinone and hydroquinone. The difference between the present example and example 3 is that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 5-isopropyl-2-methylphenol and the reaction is carried out for 24 hours. The analysis results are that the conversion rate of 5-isopropyl-2-methylphenol is 83.0%, the selectivity of thymoquinone is 87.1%, the conversion rate of 1,4-benzoquinone is 92.4%, and the selectivity of hydroquinone is 45.5%.

[0076] Example 19

[0077] The present example provides a production process for co-production of tetramethyl-1,4-benzoquinone and hydroquinone. The difference between the present example and example 3 is that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 2,3,5,6-tetramethylphenol and the reaction is carried out for 24 hours. The conversion rate of 2,3,5,6-tetramethylphenol is 100%, the selectivity of tetramethyl-1,4-benzoquinone is 81.9%, the conversion rate of 1,4-benzoquinone is 94.6%, and the selectivity of hydroquinone is 75.3%. The gas chromatogram is shown in FIG. 7, in which the position of tetramethyl-1,4-benzoquinone is marked.

[0078] Example 20

[0079] The present example provides a production process for co-production of TMBQ and hydroquinone. The difference between the present example and example 3 is that 0.5 mmol of 2,3,6-trimethylphenol is replaced by 0.5 mmol of 2,3,5-trimethylphenol and the reaction is carried out for 24 hours. The conversion rate of 2,3,5-trimethylphenol is 100%, the selectivity of TMBQ is 64.6%, the conversion rate of 1,4-benzoquinone is 88.4%, and the selectivity of hydroquinone is 62.1%.

[0080] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

[0081] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The ranges and values should be construed to be roughly about the ranges or values. The endpoints of the ranges of values will be understood to be the values which are proximate to the stated values. The ranges of values will be understood to include values which are customarily recited as being preferred. Individual values are included in the ranges of values. The values included in the ranges of values can be combined to form new ranges of values which are also within the scope of the present application.

Claims

1. A green co-production process of benzoquinone-based compounds and hydroquinone, characterized by, The application relates to a method for preparing a quinone compound by oxidizing a phenolic compound. The phenolic compound and the quinone are mixed in a molar ratio of 1:0.05-15. The reaction is as follows: wherein R1, R2, R3, R4are each independently selected from H, C 1-10 alkyl, C 1-10 alkoxy, Cl, F, Br, I or C6-C 10 aryl, or R1, R2form a ring with the carbon chain connecting R1, R2; The molar ratio of the protonic acid catalyst to the phenolic compound is 0.001-4:1, preferably 0.05-0.2:

1.

2. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The reaction temperature of the redox reaction is 20-160 DEG C, preferably 50-90 DEG C.

3. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized in that: R1, R2, R3 and R4 are independently selected from H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl, methoxy, ethoxy, isopropoxy, tert-butoxy, Cl, F, Br, I or phenyl, or R1 and R2 form a five-membered ring or a six-membered ring with the carbon chain connecting R1 and R2.

4. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The phenolic compound of formula (a) is selected from one or more of the following: 2,3,6-trimethylphenol, 2,3,5-trimethylphenol, o-cresol, m-cresol, 2,6-dimethylphenol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,5-dimethylphenol, thymol, 5-isopropyl-2-methylphenol, 5-isopropoxy-2-methylphenol, 2-methyl-1-naphthol, 2,3,5,6-tetramethylphenol, 2-methyl-5-chlorophenol, 2-chloro-3,5-dimethylphenol, 3-bromo-2,5-dimethylphenol, 2,6-dimethoxyphenol, 3-methoxyphenol, 2,3-dihydro-1H-4-indenol, 2,4-dimethyl-[1,1'-biphenyl]-3-ol, 4-methyl-[1,1'-biphenyl]-3-ol, 3,5-dimethyl-2-methoxyphenol, 3,5-dimethyl-2-iodophenol.

5. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The reaction is carried out in an atmosphere of one or more of air, nitrogen, argon, oxygen, preferably nitrogen.

6. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The alcohol solvent is one or more of methanol, ethanol, n-butanol, tert-butanol, isobutanol, n-propanol, isopropanol, pentanol, ethylene glycol, 1-hexanol or hexafluoroisopropanol.

7. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The solvent is a binary mixed solvent composed of a non-aqueous solvent and water, preferably methanol / water, ethanol / water, tert-butanol / water, n-butanol / water, isobutanol / water, acetonitrile / water, isopropanol / water, 1-hexanol / water, N,N-dimethylformamide / water, N,N-dimethylacetamide / water, tetrahydrofuran / water, hexafluoroisopropanol / water, n-hexane / water, acetone / water, ethylene glycol dimethyl ether / water, ethylene glycol monomethyl ether / water, the mass ratio of the non-aqueous solvent to water being 0.1-10:

1.

8. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: The protonic acid catalyst is selected from one or more of the following: methanesulfonic acid, trifluoromethanesulfonic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, benzoic acid, acetic acid, trifluoroacetic acid, nitric acid, hydrobromic acid, phosphoric acid, preferably one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid, acetic acid, trifluoroacetic acid.

9. The green co-production method of benzoquinone compounds and hydroquinone according to claim 1, characterized in that: ​ 10. The green co-production process of benzoquinone compounds and hydroquinone according to claim 1, characterized by: ​

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