A green co-production method of benzoquinone compounds and hydroquinone

Abstract

The present invention discloses a green co-production method for benzoquinone compounds and hydroquinone. This method involves a phenolic compound and benzoquinone undergoing a redox reaction in a protonic acid catalyst and a solvent, wherein the solvent comprises at least one of water and an alcohol solvent, to produce the benzoquinone compounds and hydroquinone. This method couples the production of trimethylbenzoquinone, which originally requires oxidation with an oxidant, with the production of hydroquinone, which requires reduction with hydrogen. Using an inexpensive acid as a catalyst for the redox reaction, the method simultaneously produces two important chemical products. The method boasts high catalytic efficiency and a high co-production yield, helping to reduce the production costs of trimethylbenzoquinone and hydroquinone and minimizing environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of fine chemical synthesis, and in particular to a green co-production method of benzoquinone compounds and hydroquinone. Background Art

[0002] Vitamin E is the general name for tocopherol compounds. It has received great attention since its discovery in 1922. Today, vitamin E is very important in the field of health products. It also has important uses in many fields such as medicine, food, feed, and cosmetics. The important intermediate in the synthesis of vitamin E is 2,3,5-trimethylhydroquinone. 2,3,5-Trimethylhydroquinone can be obtained through the catalytic hydrogenation of trimethylbenzoquinone. Trimethylbenzoquinone, also known as 2,3,5-trimethylbenzoquinone (TMBQ), is also an important pharmaceutical intermediate. TMBQ is synthesized from three main raw materials: 2,3,5-trimethylphenol, 2,3,6-trimethylphenol, and trimethylbenzene. Currently, 2,3,6-trimethylphenol is the primary raw material used to synthesize TMBQ both domestically and internationally.

[0003] The synthesis of TMBQ from 2,3,6-trimethylphenol mainly involves chemical oxidation and catalytic oxidation. In the chemical oxidation method, 2,3,6-trimethylphenol is sulfonated to produce 4-sulfonato-2,3,6-trimethylphenol, which is then oxidized with manganese dioxide to produce TMBQ. This method has the advantages of simple synthesis and low equipment investment costs. However, its disadvantages are that it is prone to environmental pollution. In the actual synthesis process, 4-sulfonato-2,3,6-trimethylphenol easily agglomerates, and the dissolution operation is 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 studies, the effects of various catalysts have been reported, and ruthenium-based catalysts have been used. A trimethylquinone yield of 83% can be achieved (Adv. Synth. Catal, DOI: 10.1002 / adsc.201000137). Furthermore, using CuCl2-poly(4-vinylpyridine) as a catalyst, DMSO as a solvent, and oxygen as an oxygen source, the conversion of 2,3,6-trimethylphenol can reach 100%, with a selectivity of 95%. Chinese patent CN96180478.5 discloses a method for oxidizing 2,3,6-trimethylphenol to TMBQ using a heteropolyacid catalytic system, achieving a TMBQ yield of 95% and a 100% conversion of 2,3,6-trimethylphenol. Chinese patent CN201711037289.4 proposes a process using tetramethylbenzene as a raw material to reduce byproduct formation and improve the yield of trimethylbenzoquinone. These catalytic oxidation methods use oxygen or hydrogen peroxide as oxidants and are relatively environmentally friendly, but their disadvantages are that the selectivity is difficult to control, the required oxygen pressure is high, the high-pressure reaction equipment is expensive, and the metal catalysts used are relatively expensive.

[0005] Hydroquinone is another widely used chemical product. As of 2018, global demand for hydroquinone was approximately 70,000 tons, primarily imported from countries such as France, Italy, and the United States. Demand for hydroquinone is gradually increasing. Also known as hydroquinone, it is primarily used in the synthesis of hydrogen peroxide, but is also widely used in the synthesis of intermediates such as photographic film, polymerization inhibitors, berberine, and epinephrine. There are over ten different techniques for synthesizing hydroquinone. The main processes include the Reppe synthesis, which uses acetylene and carbon monoxide as raw materials and reacts under high temperature and pressure, requiring expensive catalysts and making them difficult to recycle. The aniline oxidation process uses aniline as the raw material and manganese dioxide as the oxidant under acidic conditions, but this process is subject to equipment corrosion. Other methods include the p-diisopropylbenzene peroxidation process, the bisphenol A process, the hydroxylation of phenol with hydrogen peroxide, and the electrochemical method. The synthesis of hydroquinone often begins by oxidizing phenol or aniline to produce p-benzoquinone. This is because hydroquinone is easily oxidized and further oxidized to p-benzoquinone during oxidation. Therefore, p-benzoquinone must be reduced with a reducing agent such as hydrogen to produce hydroquinone. Consequently, industrial hydroquinone production methods waste oxidants and hydrogen, lacking atom economy. Summary of the Invention

[0006] The object of the present invention is to provide a green co-production method of benzoquinone compounds and hydroquinone, which can simultaneously achieve efficient preparation of benzoquinone compounds and hydroquinone without the need to add additional oxidants and reducing agents.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A preparation method for the co-production of benzoquinone compounds and hydroquinone, comprising: a phenolic compound represented by formula (a) undergoes an oxidation-reduction reaction with benzoquinone in a protonic acid catalyst and a solvent to produce a benzoquinone compound represented by formula (b) and hydroquinone, wherein the reaction formula is:

[0009]

[0010] Wherein, R1, R2, R3, and 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 and the carbon chain connecting R1 and R2 form a ring;

[0011] The solvent includes at least one of water and an alcohol solvent.

[0012] Among them, the C6~C 10 Aryl is further preferably phenyl or naphthyl; the C 1-10 The alkyl group is more preferably C 1-6 Alkyl, the C 1-10 The alkoxy group is more preferably C 1-6 Alkoxy.

[0013] Here, "at least comprising" means that the solvent may or may not contain other solvents. The alcohol solvent is further selected from one or more of methanol, ethanol, n-butanol, tert-butanol, isobutanol, n-propanol, isopropanol, pentanol, ethylene glycol, 1-hexanol, or hexafluoroisopropanol. The other solvent is further selected from one or more of acetonitrile, acetone, toluene, tetrahydrofuran, n-hexane, N,N-dimethylformamide, N,N-dimethylacetamide, 1-ethyl-3-methylimidazolium acetate, 1-ethylimidazole, diethanol dimethyl ether, and ethylene glycol methyl ether. Furthermore, the other solvent should preferably not include an oxidizing solvent, such as dimethyl sulfoxide.

[0014] The present invention innovatively combines two industrial conversion processes for preparing quinone compounds and hydroquinone, eliminating the need for the addition of other oxidants and reducing agents, thereby achieving the co-production of quinone compounds and hydroquinone. Furthermore, the method uses inexpensive proton acids as catalysts, resulting in high catalytic efficiency, high conversion rates, and good selectivity, which helps to simultaneously improve the competitiveness of the synthesis of quinone compounds and hydroquinone. Taking TMBQ as an example of a quinone compound, the key to achieving this method lies in the activation of water or alcohol solvents by p-benzoquinone, thereby utilizing the oxygen in solvent molecules such as water for an 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 proton acid used in this method as a catalyst can activate benzoquinone, thereby increasing its activity in activating water or alcohol solvents, thereby avoiding the use of metal catalysts. This method is environmentally friendly, low-cost, and has a high atom economy.

[0015] Preferably, the redox reaction is carried out in an atmosphere of one or more mixed gases of air, nitrogen, argon and oxygen, preferably a nitrogen atmosphere.

[0016] Preferably, in formula (a), R1, R2, R3, and R4 are independently selected from H, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl, methoxy, ethoxy, isopropoxy, tert-butoxy, Cl, F, Br, I, and phenyl, or R1 and R2 form a five-membered ring or a six-membered ring with the carbon chain connecting R1 and R2, and the five-membered ring or the six-membered ring may be an aliphatic ring or an aromatic ring.

[0017] Preferably, the molar ratio of the phenolic compound to the p-benzoquinone is 1:0.05 to 15. Furthermore, the molar ratio of the phenolic compound to the p-benzoquinone is 1:1 to 8. Furthermore, the molar ratio of the phenolic compound to the p-benzoquinone is 1:2 to 6.

[0018] Preferably, the reaction temperature of the redox reaction is 20-160°C, preferably 50-90°C.

[0019] Preferably, when the solvent conditions are aqueous solvent conditions, the mass ratio of the non-aqueous solvent to the water in the solvent is 1:0-15, and does not include 0. Furthermore, the mass ratio of the non-aqueous solvent to the water is 1:0.1-10; furthermore, the mass ratio of the non-aqueous solvent to the water is 1:0.1-8. Furthermore, the solvent is a binary mixed solvent of methanol / water, ethanol / water, tert-butanol / water, n-butanol / water, 1-butanol / water, acetonitrile / water, isopropanol / water, 1-hexanol / water, dimethylacetamide / water, tetrahydrofuran / water, hexafluoroisopropanol / water, n-hexane / water, acetone / water, ethylene glycol dimethyl ether / water, or ethylene glycol methyl ether / water.

[0020] There is no particularly strict requirement for the amount of the mixed solvent, as long as it can fully dissolve the reaction raw materials. Generally, the total amount of solvent used for 1 mmol of phenolic compound is about 2 to 6 g.

[0021] Preferably, the reaction is carried out at a pressure of 0.1-1 MPa.

[0022] Preferably, the reaction time of the redox reaction is 0.5-96h.

[0023] Preferably, the phenolic compound represented by formula (a) is selected from 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- A combination of one or more of 5-chlorophenol, 2-chloro-3,5-dimethylphenol, 3-bromo-2,5-dimethylphenol, 2,6-dimethoxyphenol, 3-methoxyphenol, 2,3-dihydro-1H-4-indanol, 2,4-dimethyl-[1,1'-biphenyl]-3-phenol, 4-methyl-[1,1'-biphenyl]-3-phenol, 3,5-dimethyl-2-methoxyphenol, and 3,5-dimethyl-2-iodophenol.

[0024] Preferably, the protonic acid catalyst is selected from a combination of one or more of methanesulfonic acid, trifluoromethanesulfonic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, benzoic acid, nitric acid, acetic acid, trifluoroacetic acid, nitric acid, hydrobromic acid, and phosphoric acid; further, the protonic acid catalyst is preferably a combination of one or more of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid, acetic acid, trifluoroacetic acid, and hydrochloric acid. Furthermore, the molar ratio of the protonic acid catalyst to the phenolic compound is 0.001 to 4:1, preferably 0.001 to 1:1, and more preferably 0.05 to 0.2:1.

[0025] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0026] The present invention couples the production of trimethylbenzoquinone, which originally requires oxidation by an oxidant, with the production of hydroquinone, which requires reduction by hydrogen, to produce a low-cost Acid is used as a catalyst for redox reaction, and two important chemical products are obtained at the same time. The catalytic efficiency is high and the co-production yield is high, which is beneficial to reducing the production cost of trimethylbenzoquinone and hydroquinone and reducing environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1This is the GC-MS result of 2,3,5-trimethylbenzoquinone in Example 3. The position of 2,3,5-trimethylbenzoquinone is marked in the figure, and the accurate molecular weight is given;

[0028] Figure 2 and Figure 3 They are respectively the NMR spectra of 2,3,5-trimethylbenzoquinone and hydroquinone separated by column in Example 10.

[0029] Figure 4 This is the QTOF result of the column separation product of TMBQ in Example 10;

[0030] Figure 5 This is the QTOF result of the column separation product of hydroquinone in Example 10;

[0031] Figure 6 GC-MS results of 2,6-dimethyl-1,4-benzodiquinone in Example 15 are shown. The position of 2,6-dimethyl-1,4-benzodiquinone is marked in the figure.

[0032] Figure 7 This is the GC-MS result of tetramethyl-1,4-p-benzoquinone in Example 19. The position of tetramethyl-1,4-p-benzoquinone is marked in the figure; DETAILED DESCRIPTION

[0033] The above scheme is further described below in conjunction with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are generally the conditions in routine experiments.

[0034] Unless otherwise specified in the following examples, all raw materials were purchased from commercial sources or prepared by conventional methods in the art.

[0035] In the following, all reaction conversions and yields were determined by gas chromatography (using commercially available starting materials and products as standard curves).

[0036] Comparative Example 1

[0037] This comparative example provides a production process for the co-production of TMBQ and hydroquinone, which adopts the following synthesis path:

[0038]

[0039] The method comprises the following steps: adding 0.5 mmol of 2,3,6-trimethylphenol, 1.5 mmol of 1,4-p-benzoquinone, 1.4 g of methanol, and 0.6 g of water into a 20 mL reaction bottle, adding a magnetic bar, evacuating the solution, and connecting a nitrogen gas bag (0.1 MPa). The reaction is carried out at 70° C. for 24 hours, wherein the conversion rate of 2,3,6-trimethylphenol is 100%, the selectivity of TMBQ is 70.9%, the conversion rate of 1,4-p-benzoquinone is 86.9%, and the selectivity of hydroquinone is 41.3%.

[0040] Example 1

[0041] This embodiment provides a production process for the co-production of TMBQ and hydroquinone, which adopts the following synthesis path:

[0042]

[0043] The method comprises the following steps: adding 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, and 0.1 mmol of hydrochloric acid solution (mass concentration of 37%) into a 20 mL reaction bottle, adding a magnetic bar, evacuating the bottle and then connecting a nitrogen gas bag (0.1 MPa), reacting at 70° C. for 2 hours, sampling, and performing gas chromatography analysis. The results show that 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%.

[0044] Example 2

[0045] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 1 in that 0.1 mmol of trifluoroacetic acid is used in place of 0.1 mmol of hydrochloric acid. Analysis results showed a 2,3,6-trimethylphenol conversion of 94.6%, a TMBQ selectivity of 96.0%, a 1,4-p-benzoquinone conversion of 77.8%, and a hydroquinone selectivity of 60.8%.

[0046] Example 3

[0047] This embodiment provides a production process for the co-production of TMBQ and hydroquinone. Compared with Example 1, this embodiment differs in that 0.1 mmol of hydrochloric acid is replaced with 0.1 mmol of trifluoromethanesulfonic acid for the reaction. The analysis results show 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%. The gas chromatogram is shown in FIG. Figure 1 , where the TMBQ gas phase position is marked.

[0048] Example 4

[0049] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction is performed using a molar amount of trifluoromethanesulfonic acid of 0.05 mmol. Analysis results show a 2,3,6-trimethylphenol conversion of 93.2%, a TMBQ selectivity of 93.9%, a 1,4-p-benzoquinone conversion of 72.1%, and a hydroquinone selectivity of 65.8%.

[0050] Example 5

[0051] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction is performed using a molar amount of 0.5 mmol of trifluoromethanesulfonic acid. Analysis results show a 2,3,6-trimethylphenol conversion of 95.0%, a TMBQ selectivity of 100%, a 1,4-p-benzoquinone conversion of 91.7%, and a hydroquinone selectivity of 44.9%.

[0052] Example 6

[0053] This example provides a production process for the co-production of TMBQ and hydroquinone. Compared to Example 3, this example differs in that the reaction is conducted using a molar amount of trifluoromethanesulfonic acid of 2 mmol. Analysis results show a 2,3,6-trimethylphenol conversion of 89.6%, a TMBQ selectivity of 70.8%, a 1,4-p-benzoquinone conversion of 66.4%, and a hydroquinone selectivity of 79.2%.

[0054] Example 7

[0055] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction temperature is 50°C. Analysis results show that the conversion of 2,3,6-trimethylphenol is 87.3%, the selectivity for TMBQ is 93.2%, the conversion of 1,4-p-benzoquinone is 69.6%, and the selectivity for hydroquinone is 79.2%.

[0056] Example 8

[0057] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the solvents used are acetonitrile (1.4 g) and water (0.6 g). Analysis results show a 2,3,6-trimethylphenol conversion of 82.1%, a TMBQ selectivity of 79.3%, a 1,4-p-benzoquinone conversion of 61.9%, and a hydroquinone selectivity of 78.2%.

[0058] Example 9

[0059] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the reaction temperature is 50°C and the reaction time is 6.5 hours. Analysis results show a 2,3,6-trimethylphenol conversion rate of 93.3%, a TMBQ selectivity of 83.5%, a 1,4-p-benzoquinone conversion rate of 67.6%, and a hydroquinone selectivity of 88.2%.

[0060] Example 10

[0061] This example provides a production process for the co-production of TMBQ and hydroquinone. Compared to Example 3, this example differs in that the molar amounts of 2,3,6-trimethylphenol and 1,4-p-benzoquinone are increased 10-fold. 1 mmol of trifluoromethanesulfonic acid, 14 g of methanol, and 6 g of water are added. The reaction is allowed to proceed for 24 hours. Gas chromatography-mass spectrometry analysis shows a 100% conversion rate for 2,3,6-trimethylphenol, an 82.1% conversion rate for 1,4-p-benzoquinone, a 95.9% selectivity for TMBQ, and a 77.7% selectivity for hydroquinone. An appropriate amount of silica gel is then added, the mixture is spin-dried, and column chromatography is performed to separate the two products. After drying, the products are then analyzed by mass spectrometry. The final yield of TMBQ is 93.1%, and the yield of hydroquinone is 62.3%. Figure 2 and 3 These are the NMR spectra of TMBQ and hydroquinone obtained by column separation, Figure 4 and 5 These are the QTOF results of TMBQ and hydroquinone obtained by column separation.

[0062] Example 11

[0063] This example provides a production process for the co-production of TMBQ and hydroquinone. Compared to Example 3, this example uses dimethyl sulfoxide (1.4 g) and water (0.6 g) as the solvent, and the reaction is carried out for 24 hours. Analysis results show a 2,3,6-trimethylphenol conversion of 99.7%, a TMBQ selectivity of 25.7%, a 1,4-p-benzoquinone conversion of 97.7%, and a hydroquinone selectivity of 36.9%.

[0064] Example 12

[0065] This embodiment provides a production process for the co-production of TMBQ and hydroquinone. Compared with Example 3, this embodiment differs in that the solvent types are changed to methanol and water. The reaction is carried out under air conditions for 24 hours. 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%.

[0066] The results of Example 11 and Example 12 show that the reaction results are poor when using the oxidizing solvent dimethyl sulfoxide or the reaction atmosphere is air. It is possible that the oxidizing environment will adversely interfere with the redox reaction.

[0067] Example 13

[0068] This example provides a production process for the co-production of TMBQ and hydroquinone. This example differs from Example 3 in that the solvent system is ethylene glycol monomethyl ether (1.4 g) and water (0.6 g), and the reaction is performed for 24 hours. Analysis results show a 2,3,6-trimethylphenol conversion of 98.6%, a TMBQ selectivity of 97.0%, a 1,4-p-benzoquinone conversion of 86.6%, and a hydroquinone selectivity of 71.3%.

[0069] Example 14

[0070] This embodiment provides a production process for the co-production of 2,6-dimethyl-1,4-benzoquinone and hydroquinone. Compared with Example 3, this embodiment differs 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 show 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. Figure 6 , in which the gas phase position of 2,6-dimethyl-1,4-benzodiquinone is marked.

[0071] Example 15

[0072] This example provides a production process for the co-production of 2,5-dimethyl-1,4-p-benzoquinone and hydroquinone. This example differs from Example 3 in that 0.5 mmol of 2,5-dimethylphenol is replaced with 0.5 mmol of 2,3,6-trimethylphenol, and the reaction is carried out for 24 hours. Analysis results show a 2,5-dimethylphenol conversion rate of 96.4%, a 2,5-dimethyl-1,4-p-benzoquinone selectivity of 80.2%, a 1,4-p-benzoquinone conversion rate of 93.4%, and a hydroquinone selectivity of 58.4%.

[0073] Example 16

[0074] This example provides a process for the co-production of thymoquinone and hydroquinone. This example differs from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced with 0.5 mmol of thymol, and the reaction is continued for 24 hours. Analysis results show a thymol conversion of 86.2%, a thymoquinone selectivity of 48.9%, a 1,4-p-benzoquinone conversion of 92.1%, and a hydroquinone selectivity of 48.9%.

[0075] Example 17

[0076] This example provides a production process for the co-production of 2,3-dimethyl-1,4-p-benzoquinone and hydroquinone. This example differs from Example 3 in that 0.5 mmol of 2,3-dimethylphenol is replaced with 0.5 mmol of 2,3-dimethylphenol, and the reaction is allowed to proceed for 24 hours. Analysis results showed a 2,3-dimethylphenol conversion rate of 94.3%, a 2,3-dimethyl-1,4-p-benzoquinone selectivity of 82.7%, a 1,4-p-benzoquinone conversion rate of 90.4%, and a hydroquinone selectivity of 49.0%.

[0077] Example 18

[0078] This example provides a production process for the co-production of thymoquinone and hydroquinone. This example differs from Example 3 in that 0.5 mmol of 2,3,6-trimethylphenol is replaced with 0.5 mmol of 5-isopropyl-2-methylphenol, and the reaction is allowed to proceed for 24 hours. Analysis results showed a 5-isopropyl-2-methylphenol conversion of 83.0%, a thymoquinone selectivity of 87.1%, a 1,4-p-benzoquinone conversion of 92.4%, and a hydroquinone selectivity of 45.5%.

[0079] Example 19

[0080] This embodiment provides a production process for the co-production of tetramethyl-1,4-p-benzoquinone and hydroquinone. Compared with Example 3, this embodiment differs in 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-p-benzoquinone is 81.9%, the conversion rate of 1,4-p-benzoquinone is 94.6%, and the selectivity of hydroquinone is 75.3%. The gas chromatogram is shown in FIG. Figure 7 , where the gas phase position of tetramethyl-1,4-p-benzoquinone is marked.

[0081] Example 20

[0082] This example provides a production process for the co-production of TMBQ and hydroquinone. Compared with Example 3, this example differs in that 0.5 mmol of 2,3,6-trimethylphenol is replaced with 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-p-benzoquinone is 88.4%, and the selectivity of hydroquinone is 62.1%.

[0083] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

[0084] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A green co-production method of benzoquinone compounds and hydroquinone, characterized in that: include: The phenolic compound represented by formula (a) undergoes an oxidation-reduction reaction with benzoquinone in a protonic acid catalyst and a solvent to generate a benzoquinone compound represented by formula (b) and hydroquinone; The reaction is as follows: ； Wherein, R1, R2, R3, and R4 are independently selected from H, C 1-10 Alkyl, C 1-10 Alkoxy, Cl, F, Br, I or C6~C 10 Aryl, or R1, R2 and the carbon chain connecting R1 and R2 form a ring; The solvent is a binary mixed solvent of 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, and ethylene glycol monomethyl ether / water, wherein the mass ratio of the non-aqueous solvent to the water is 0.1 to 10:1; The molar ratio of the protonic acid catalyst to the phenolic compound is 0.05-0.2:1; The reaction temperature of the redox reaction is 50-90°C; The protonic acid catalyst is selected from one or more combinations of methanesulfonic acid, trifluoromethanesulfonic acid, p-toluenesulfonic acid, hydrochloric acid, acetic acid, and trifluoroacetic acid.

2. The green co-production method of benzoquinone compounds and hydroquinone according to claim 1, characterized in that: The molar ratio of the phenolic compound to benzoquinone is 1:0.05-15.

3. The green co-production method 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 method of benzoquinone compounds and hydroquinone according to claim 1, characterized in that: The phenolic compound represented by formula (a) is selected from 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- A combination of one or more of chlorophenol, 2-chloro-3,5-dimethylphenol, 3-bromo-2,5-dimethylphenol, 2,6-dimethoxyphenol, 3-methoxyphenol, 2,3-dihydro-1H-4-indanol, 2,4-dimethyl-[1,1'-biphenyl]-3-phenol, 4-methyl-[1,1'-biphenyl]-3-phenol, 3,5-dimethyl-2-methoxyphenol, and 3,5-dimethyl-2-iodophenol.

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

6. The green co-production method of benzoquinone compounds and hydroquinone according to claim 5, characterized in that: The reaction was carried out under a nitrogen atmosphere.

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