The purity of 4, 4apos is high; process for the preparation of-biphenol

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of high-purity 4, 4 '-biphenol, which comprises the following steps: preparing 1, 4-cyclohexanedione, phenol, a solvent, an additive and a catalyst; the method comprises the following steps: pretreatment: heating 1, 4-cyclohexanedione, phenol, a solvent, an additive and a catalyst in the presence of an oxidant or a hydrogen accepting reagent, carrying out heat preservation and stirring, and sequentially carrying out a coupling reaction and a catalytic dehydrogenation reaction to obtain a reaction solution; post-treatment: cooling the reaction liquid to room temperature, extracting with a saturated sodium bicarbonate solution and an ethyl acetate solution, carrying out rotary evaporation on an organic layer, and carrying out reduced pressure suction filtration to obtain a crude product; and refining, recrystallizing the crude product in a mixed solution of water and ethanol, and carrying out reduced pressure suction filtration to obtain high-purity 4, 4 '-biphenol.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for preparing high-purity 4,4'-biphenyl diphenol. Background Art

[0002] 4,4'-Biphenyl (4,4'-dihydroxybiphenyl) is an important organic intermediate with widespread applications in medicine, materials science, and fine chemicals. However, the selection of its synthesis method has always been a hot topic and a challenge. Currently, common synthesis methods include biphenyl sulfonation alkaline fusion, biocatalysis, noble metal-catalyzed coupling reaction synthesis, benzidine method, electrochemical synthesis, and 2,6-di-tert-butylphenol oxidative coupling. However, these methods all have certain limitations in practical application.

[0003] For example, the yield of the biphenyl sulfonation alkaline fusion method is low and the catalytic process is complicated; the reaction time of the biocatalytic method is too long; the catalyst of the precious metal catalytic coupling reaction synthesis method is difficult to recover; the benzidine method causes serious environmental pollution; and the 2,6-di-tert-butylphenol oxidative coupling method produces too many by-products.

[0004] Comprehensive existing preparation processes show that it is impossible to easily prepare high-purity 4,4'-biphenol. Therefore, how to overcome the defect of low purity in the industrial preparation of 4,4'-biphenol is a technical problem that needs to be solved urgently in this field.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the Invention

[0006] The embodiments of the present disclosure at least provide a method for preparing high-purity 4,4'-biphenyl diphenol.

[0007] In a first aspect, an embodiment of the present disclosure provides a method for preparing high-purity 4,4'-biphenol, comprising the following steps: preparing 1,4-cyclohexanedione, phenol, a solvent, an additive, and a catalyst; pretreatment, specifically heating and stirring 1,4-cyclohexanedione, phenol, a solvent, an additive, and a catalyst in the presence of an oxidant or a hydrogen accepting reagent, and sequentially performing a coupling reaction and a catalytic dehydrogenation reaction to obtain a reaction liquid; post-treatment, specifically cooling the reaction liquid to room temperature, extracting with a saturated sodium bicarbonate solution and an ethyl acetate solution, rotary evaporating the organic layer, and filtering under reduced pressure to obtain a crude product; and refining, recrystallizing the crude product in a mixed solution of water and ethanol, and filtering under reduced pressure to obtain high-purity 4,4'-biphenol.

[0008] In an optional embodiment, the catalyst includes at least one of an acid catalyst and a metal catalyst; the acid catalyst includes any one of hydrochloric acid, hydrobromic acid, p-toluenesulfonic acid, acetic acid, sulfuric acid, ferric chloride, phosphoric acid and zinc chloride, or a combination of at least two thereof; the metal catalyst includes any one of Pd-Fe / C, Cu / C, Pd / MOF, Fe-MOF and Cu-MOF, or a combination of at least two thereof.

[0009] In an optional embodiment, the solvent includes any one or a combination of at least two of toluene, xylene, methanol, ethanol, acetone, tetrahydrofuran, ethyl acetate, acetonitrile, dioxane, N,N-dimethylacetamide and dimethyl sulfoxide.

[0010] In an optional embodiment, the oxidant or hydrogen accepting reagent includes any one of oxygen, hydrogen peroxide, sodium hypochlorite, benzoquinone, and naphthoquinone.

[0011] In an optional embodiment, the chemical formula of the coupling reaction specifically includes:

[0012]

[0013] In an optional embodiment, the chemical formula of the catalytic dehydrogenation reaction specifically includes:

[0014]

[0015] In an optional embodiment, in the pretreatment, the molar ratio of 1,4-cyclohexanedione to phenol is 1:1-10.

[0016] In an optional embodiment, in the pretreatment, the molar ratio of the acid catalyst to 1,4-cyclohexanedione is 0.1 to 1:1; in the pretreatment, the molar ratio of the metal catalyst to 1,4-cyclohexanedione is 0.0005 to 0.002:1.

[0017] In an optional embodiment, in the pretreatment, the reaction temperature is 40-150° C., the pressure in the reaction container is 0.01-0.2 MPa, and the reaction time is 10-20 h.

[0018] In an optional embodiment, in the post-treatment, the temperature of the rotary evaporation is 40-70° C., and the vacuum degree of the pressure in the reaction container after decompression is 0.005-0.01 MPa.

[0019] The beneficial effects of the present invention are that the preparation method of high-purity 4,4'-biphenol adopts a one-pot method to prepare 4,4'-biphenol, which is green and environmentally friendly, and the crude product obtained after the coupling reaction and the catalytic dehydrogenation reaction only needs to be recrystallized and refined to obtain a high-purity product. Oxygen, hydrogen peroxide, nitric acid, etc. are used as oxidants, and ethanol, acetic acid, water, toluene, etc. are used as solvents. Under suitable reaction conditions, the synthesis of the target product with high yield and high purity can be achieved.

[0020] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 The NMR nuclear magnetic resonance image of 4,4'-biphenyldiphenol provided in the embodiments of the present disclosure;

[0024] Figure 2 13C-NMR nuclear magnetic resonance carbon spectrum of 4,4'-biphenyldiphenol provided in the embodiments of the present disclosure;

[0025] Figure 3 This is the HNMR nuclear magnetic resonance hydrogen spectrum of 4,4'-biphenyldiphenol provided in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Thus, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations, aspects, or designs. Instead, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0028] Herein, example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements, rather than modifying individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0029] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless otherwise clearly indicated herein. The terms "comprise", "include" and "have" are inclusive and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the particular order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0030] Patent CN 113683488 A uses biphenyl as a raw material and prepares 4,4-dihydroxybiphenyl by a transition metal-catalyzed oxygen oxidation method. The catalyst used in this process is a transition metal-doped mesoporous molecular sieve-supported piperazine ionic liquid. Its preparation process involves multiple steps and requires specific chemical reagents (such as 1,4-diethylpiperazine, 3-chloropropyltriethoxysilane, etc.), which is relatively expensive. In addition, the production cost is increased. The reaction needs to be carried out under specific temperature, pressure and stirring conditions, which requires high accuracy of operation and high energy consumption cost. The whole process is relatively cumbersome, which is not conducive to the continuous and automated large-scale industrial production.

[0031] US Patent No. 6410238 provides a method for preparing 4,4-dihydroxybiphenyl using biphenyl as a raw material through sulfuric acid sulfonation and sodium hydroxide alkali fusion. This process requires the use of large amounts of strong acids and bases, as well as high reaction temperatures, and has significant safety and environmental drawbacks. Furthermore, the yield and purity are low.

[0032] Patent CN109896925A provides a one-step method for synthesizing 4,4'-dihydroxybiphenyl using biphenyl as the raw material, hydrogen peroxide as the oxidant, and chromium-loaded HZSM-5 molecular sieve as the catalyst. While this method is simple and produces minimal waste, the initial catalyst preparation process is complex, impacting overall economic benefits.

[0033] Patents such as US 4,153,509 and JP 2010-227000 A provide methods for preparing 4,4-dihydroxybiphenyl using biphenyl as a raw material through a microbial catalytic process. This method requires the cultivation and screening of highly active microbial strains and ensuring their stability in large-scale cultivation. The microbial conversion reaction requires a long time and has limited product yields. The bioconversion process may produce a variety of byproducts, necessitating the development of efficient separation and purification technologies to obtain high-purity biphenyl diphenol.

[0034] Patent CN108715574A provides a method for preparing 4,4'-dihydroxybiphenyl by a one-step coupling reaction using para-halogenated phenol as a raw material, a divalent copper salt and rare earth metal samarium as catalysts. This method has high requirements for the catalyst and requires a large amount of catalyst, and recovery and separation are difficult, making it unsuitable for industrial production.

[0035] Patents such as US 6,441,248 B1, PCT / US2002 / 027221, CN 111606784 A, CN 112142570 A, CN 113956135 B, and CN 116178111 A provide methods for preparing 4,4-dihydroxyphenol using 2,6-dialkylphenol as a raw material through oxidative coupling catalyzed by sulfuric acid, p-toluenesulfonic acid, or other Lewis acids. Reduction and dealkylation reactions are carried out at high temperatures of 160°C-200°C to produce 4,4-dihydroxyphenol in three steps. This method requires the use of various strong acids, high reaction temperatures, and high energy consumption. The process is lengthy, and the oxidative coupling, reduction, and de-tert-butylation reactions must be closely linked, making time and logistics coordination between these steps challenging in large-scale production. Different reactions require switching reactors or adjusting equipment configurations, impacting production efficiency. The entire process generates significant amounts of wastewater and exhaust gas, which can be environmentally unfriendly if not properly handled. The raw material 2,6-di-tert-butylphenol is expensive and currently the domestic market mainly relies on imports.

[0036] Patents CN 114181052 A, CN 113416119 A, and JPH04338347 A, among others, provide a process for preparing 2,6-di-tert-butylphenol using cost-effective phenol and isobutylene via acid-catalyzed coupling, base-catalyzed oxidation to produce tetra-tert-butylphenol, and strong-acid-catalyzed dealkylation to produce 4,4-dihydroxyphenol. This process requires strong acid and base, as well as high temperature. The first step to prepare high-purity 2,6-di-tert-butylphenol is difficult, and the targeted generation of 2,6-substituted products easily generates other byproducts, making post-processing difficult. This results in low final yields, complex steps, long production cycles, demanding equipment, and high energy consumption.

[0037] The defects in the above solutions are the results obtained by the inventors after practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed by this disclosure for the above problems below should be the contributions made by the inventors to this disclosure during the disclosure process.

[0038] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0039] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0040] The present disclosure provides a method for preparing high-purity 4,4'-biphenyldiphenol, comprising the following steps: preparing 1,4-cyclohexanedione, phenol, a solvent, an additive, and a catalyst; pretreatment, specifically heating and stirring 1,4-cyclohexanedione, phenol, a solvent, an additive, and a catalyst in the presence of an oxidant or a hydrogen accepting reagent, and sequentially performing a coupling reaction and a catalytic dehydrogenation reaction to obtain a reaction solution; post-treatment, specifically cooling the reaction solution to room temperature, extracting with a saturated sodium bicarbonate solution and an ethyl acetate solution, rotary evaporating the organic layer, and filtering under reduced pressure to obtain a crude product; and refining, recrystallizing the crude product in a mixed solution of water and ethanol, and filtering under reduced pressure to obtain high-purity 4,4'-biphenyldiphenol.

[0041] In some embodiments, specifically, the catalyst includes at least one of an acid catalyst and a metal catalyst; the acid catalyst includes any one of hydrochloric acid, hydrobromic acid, p-toluenesulfonic acid, acetic acid, sulfuric acid, ferric chloride, phosphoric acid and zinc chloride, or a combination of at least two thereof, preferably hydrochloric acid; the metal catalyst includes any one of Pd-Fe / C, Cu / C, Pd / MOF, Fe-MOF and Cu-MOF, or a combination of at least two thereof, preferably Pd-Fe / C.

[0042] In some embodiments, specifically, the solvent includes any one or a combination of at least two of toluene, xylene, methanol, ethanol, acetone, tetrahydrofuran, ethyl acetate, acetonitrile, dioxane, N,N-dimethylacetamide and dimethyl sulfoxide, preferably ethanol.

[0043] In some embodiments, specifically, the oxidant or hydrogen accepting reagent includes any one of oxygen, hydrogen peroxide, sodium hypochlorite, benzoquinone, and naphthoquinone.

[0044] In some embodiments, specifically, the chemical formula of the coupling reaction specifically includes:

[0045]

[0046] Specifically, phenol and 1,4-cyclohexanedione undergo a coupling reaction under acidic conditions to obtain an intermediate product.

[0047] In some embodiments, specifically, the chemical formula of the catalytic dehydrogenation reaction specifically includes:

[0048]

[0049] Specifically, under the catalysis of metallic palladium, the dehydrogenation rate of the intermediate product is much higher than the reaction rate of other by-products, so high-purity 4,4'-biphenol can be synthesized.

[0050] In some embodiments, specifically, in the pretreatment, the molar ratio of 1,4-cyclohexanedione to phenol is 1:1 to 10, preferably 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, or 1:10.

[0051] In some embodiments, specifically, in the pretreatment, the molar ratio of the acid catalyst to 1,4-cyclohexanedione is 0.1 to 1:1; in the pretreatment, the molar ratio of the metal catalyst to 1,4-cyclohexanedione is 0.0005 to 0.002:1, preferably 0.0005:1, 0.0008:1, 0.001:1, 0.0015:1, 0.0018:1, 0.002:1.

[0052] In some embodiments, specifically, in the pretreatment, the reaction temperature is 40-150° C., the pressure in the reaction container is 0.1-0.2 MPa, and the reaction time is 10-20 h.

[0053] In some embodiments, specifically, in the post-treatment, the temperature of the rotary evaporation is 40-100° C., and the pressure in the reaction container after decompression is 0.005-0.01 MPa.

[0054] Example 1

[0055] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of ethanol, 7.5 mL of hydrochloric acid and 0.2 g of Pd-Fe / C catalyst.

[0056] Reaction process: Connect an oxygen ball through a three-way valve with a pressure of 0.02 MPa, heat the reaction bottle to 80°C, and stir for 18 hours.

[0057] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.006 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (10.3 g) was then filtered under reduced pressure.

[0058] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 8.5 g of the refined product with a yield of 91%.

[0059] Example 2

[0060] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of methanol, 2.2 mL of p-toluenesulfonic acid, 0.15 g of Pd / MOF catalyst, and 2.8 mL of hydrogen peroxide.

[0061] Reaction process: nitrogen was introduced at a pressure of 0.01 MPa, the reaction flask was heated to 60°C, and stirred for 24 hours.

[0062] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 50°C until no more liquid was evaporated. The crude product (9.5 g) was then filtered under reduced pressure.

[0063] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 8.3 g of the refined product with a yield of 89%.

[0064] Example 3

[0065] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of toluene, 7.5 mL of hydrochloric acid, 0.15 g of Pd / MOF catalyst, and 2.8 mL of hydrogen peroxide.

[0066] Reaction process: nitrogen was introduced at a pressure of 0.03 MPa, the reaction flask was heated to 65°C, and stirred for 24 hours.

[0067] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.006 MPa and a temperature of 50°C until no more liquid was evaporated. The crude product (8.8 g) was then filtered under reduced pressure.

[0068] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 7.1 g of the refined product with a yield of 76%.

[0069] Example 4

[0070] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of methanol, 7.5 mL of hydrochloric acid, and 0.15 g of Pd / MOF catalyst.

[0071] Reaction process: introduce oxygen at a pressure of 0.01 MPa, heat the reaction flask to 40°C, and stir for 22 hours.

[0072] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (9.3 g) was then filtered under reduced pressure.

[0073] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 7.7 g of the refined product with a yield of 83%.

[0074] Example 5

[0075] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of xylene, 20 mL of acetic acid, and 0.15 g of Pd / MOF catalyst.

[0076] Reaction process: introduce oxygen, heat the reaction flask to 100°C at a pressure of 0.06 MPa, and stir for 10 hours.

[0077] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a rotary evaporation temperature of 70°C until no more liquid was evaporated. The product was then filtered under reduced pressure and vacuumed to 0.01 MPa at a rotary evaporation temperature of 40°C to obtain 8.8 g of crude product.

[0078] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 7.5 g of the refined product with a yield of 81%.

[0079] Example 6

[0080] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 15 mL of phenol, 35 mL of xylene, 2.5 mL of sulfuric acid, and 0.5 g of Cu-MOF catalyst.

[0081] Reaction process: introduce oxygen, heat the reaction flask to 80°C at a pressure of 0.1 MPa, and stir for 13 hours.

[0082] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (6.1 g) was then filtered under reduced pressure.

[0083] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 5.4 g of the refined product with a yield of 58%.

[0084] Example 7

[0085] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of N,N-dimethylacetamide, 7.5 mL of hydrochloric acid, and 0.5 g of Cu / C catalyst.

[0086] Reaction process: Connect an oxygen ball through a three-way connection with a pressure of 0.01 MPa, heat the reaction bottle to 150°C, and stir for 9 hours.

[0087] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.01 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (7.3 g) was then filtered under reduced pressure.

[0088] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 6.1 g of the refined product with a yield of 66%.

[0089] Example 8

[0090] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 20 mL of ethanol, 15 mL of acetic acid, and 0.15 g of Pd / MOF catalyst.

[0091] Reaction process: Connect an oxygen ball through a three-way valve with a pressure of 0.01 MPa, heat the reaction bottle to 80°C, and stir for 18 hours.

[0092] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (5.5 g) was then filtered under reduced pressure.

[0093] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 4.9 g of the refined product with a yield of 53%.

[0094] Example 9

[0095] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 10 mL of phenol, 35 mL of ethanol, 7.5 mL of hydrochloric acid, 0.15 g of Pd / MOF catalyst, and 1.85 g of sodium hypochlorite.

[0096] Reaction process: introduce oxygen, heat the reactor to 50°C at a pressure of 0.05 MPa, and stir for 18 hours.

[0097] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (6.8 g) was then filtered under reduced pressure.

[0098] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 5.9 g of the refined product with a yield of 64%.

[0099] Example 10

[0100] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 12.8 g of 4-chlorophenol, 50 mL of ethanol, 7.5 mL of hydrochloric acid, and 0.1 g of Pd / C catalyst.

[0101] Reaction process: nitrogen was introduced at a pressure of 0.05 MPa, the reactor was heated to 45°C, and stirred for 18 hours.

[0102] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (9.8 g) was then filtered under reduced pressure.

[0103] Refining: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 7.1 g of the refined product with a yield of 76%.

[0104] Example 11

[0105] Preparation of raw materials: In a 100 mL single-necked reaction flask, add 1,4-cyclohexanedione, 11 g 1,4-hydroquinone, 50 mL ethanol, 7.5 mL hydrochloric acid and 0.15 g Pd-Fe / C catalyst.

[0106] Reaction process: Connect a nitrogen balloon through a three-way connection with a pressure of 0.01 MPa, heat the reaction bottle to 80°C, and stir for 18 hours.

[0107] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.005 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (7.6 g) was then filtered under reduced pressure.

[0108] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 6.4 g of the refined product with a yield of 69%.

[0109] Example 12

[0110] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of ethyl acetate, 20 mL of acetic acid, and 0.15 g of Pd / MOF catalyst.

[0111] Reaction process: introduce oxygen at a pressure of 0.05 MPa, heat the reactor to 40°C, and stir for 24 hours.

[0112] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.008 MPa and a temperature of 60°C until no more liquid was evaporated. The crude product (6.6 g) was then filtered under reduced pressure.

[0113] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 5.8 g of the refined product with a yield of 62%.

[0114] Example 13

[0115] Raw material preparation: In a 100 mL single-necked reaction flask, add 5.5 g of 1,4-cyclohexanedione, 25 mL of phenol, 25 mL of dimethyl sulfoxide, 20 mL of acetic acid, and 0.15 g of Pd / MOF catalyst.

[0116] Reaction process: Connect an oxygen ball through a three-way connection with a pressure of 0.2 MPa, heat the reactor to 50°C, and keep stirring for 8 hours.

[0117] Post-treatment: After the reaction, the reaction solution was cooled to room temperature and extracted with 100 mL of saturated sodium bicarbonate solution and 100 mL of ethyl acetate solution. The organic layer was rotary evaporated at a vacuum of 0.009 MPa and a temperature of 45°C until no more liquid was evaporated. The crude product (8.9 g) was then filtered under reduced pressure.

[0118] Purification: The crude product was recrystallized from a mixed solution of ethanol and water, and filtered under reduced pressure to obtain 7.2 g of the refined product with a yield of 77%.

[0119] Specifically, the refined product is subjected to nuclear magnetic resonance (NMR) such as Figure 1 As shown, the nuclear magnetic resonance carbon spectrum (13C-NMR) is as follows Figure 2 As shown and nuclear magnetic resonance hydrogen spectrum (HNMR) as Figure 3 As shown, analysis and identification confirmed that it was the target product 4,4'-biphenyldiphenol with a purity of up to 99.9%.

[0120] Specifically, Figure 2 middle 13 C NMR (101MHz, DMSO-d6) δ156.68, 131.64, 127.46, 116.03.

[0121] Specifically, Figure 3 middle 1 H NMR (400MHz, DMSO-d6) δ9.38 (s, 1H), 7.36 (d, J = 8.6 Hz, 2H), 6.79 (d, J = 8.6 Hz, 2H).

[0122] In summary, the preparation method of high-purity 4,4'-biphenol adopts a one-pot method to prepare 4,4'-biphenol, which is green and environmentally friendly. The crude product obtained after the coupling reaction and catalytic dehydrogenation reaction only needs to be recrystallized and refined to obtain a high-purity product. Oxygen, hydrogen peroxide, nitric acid, etc. are used as oxidants, and ethanol, acetic acid, water, toluene, etc. are used as solvents. Under suitable reaction conditions, the synthesis of the target product with high yield and high purity can be achieved.

[0123] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for preparing high-purity 4,4'-biphenyl diphenol, characterized in that: The steps include: preparing 1,4-cyclohexanedione, phenol, solvent, additives and catalyst; Pretreatment, specifically, heating 1,4-cyclohexanedione, phenol, a solvent, and a catalyst in the presence of an oxidant or a hydrogen acceptor, and stirring while maintaining the temperature, and sequentially performing a coupling reaction and a catalytic dehydrogenation reaction to obtain a reaction solution; The post-treatment comprises cooling the reaction solution to room temperature, extracting with a saturated sodium bicarbonate solution and an ethyl acetate solution, rotary evaporating the organic layer and filtering under reduced pressure to obtain a crude product; After purification, the crude product was recrystallized in a mixed solution of water and ethanol, and filtered under reduced pressure to obtain high-purity 4,4'-biphenyldiphenol.

2. The preparation method according to claim 1, wherein The catalyst comprises at least one of an acid catalyst and a metal catalyst; The acid catalyst includes any one or a combination of at least two of hydrochloric acid, hydrobromic acid, p-toluenesulfonic acid, acetic acid, sulfuric acid, ferric chloride, phosphoric acid and zinc chloride; The metal catalyst includes any one of Pd-Fe / C, Cu / C, Pd / MOF, Fe-MOF and Cu-MOF, or a combination of at least two thereof.

3. The preparation method according to claim 1, wherein The solvent includes any one or a combination of at least two of toluene, xylene, methanol, ethanol, acetone, tetrahydrofuran, ethyl acetate, acetonitrile, dioxane, N,N-dimethylacetamide and dimethyl sulfoxide.

4. The preparation method according to claim 1, wherein The oxidant or hydrogen accepting agent includes any one of oxygen, hydrogen peroxide, sodium hypochlorite, benzoquinone, and naphthoquinone.

5. The preparation method according to claim 1, wherein The chemical formula of the coupling reaction specifically includes:

6. The preparation method according to claim 1, wherein The chemical formula of the catalytic dehydrogenation reaction specifically includes:

7. The preparation method according to claim 1, wherein In the pretreatment, the molar ratio of 1,4-cyclohexanedione to phenol is 1:1-10.

8. The preparation method according to claim 2, wherein In the pretreatment, the molar ratio of the acid catalyst to 1,4-cyclohexanedione is 0.1 to 1:1; In the pretreatment, the molar ratio of the metal catalyst to 1,4-cyclohexanedione is 0.0005 to 0.002:

1.

9. The preparation method according to claim 1, wherein In the pretreatment, the reaction temperature is 40 to 150° C., the pressure in the reaction container is 0.01 to 0.2 MPa, and the reaction time is 10 to 20 hours.

10. The preparation method according to claim 1, wherein In the post-treatment, the temperature of the rotary evaporation is 40-70° C., and the vacuum degree of the pressure in the reaction container after decompression is 0.005-0.01 MPa.

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