Synthesis method of 4, 4 '-biphenyl diquinone compound and preparation method of 4, 4'-biphenol

Abstract

The invention discloses 4, 4 '-diphenylmethane. The invention discloses a synthesis method of a 2, 6-disubstituted phenol compound and a preparation method of the 4, 4 '-biphenyl diquinone compound, and the method comprises the following steps: in the presence of a heterogeneous oxidative coupling catalyst, 2, 6-disubstituted phenol compound is subjected to oxidative coupling reaction, the heterogeneous oxidative coupling catalyst is a modified chitosan supported copper-based complex, and the modified chitosan supported copper-based complex is a modified chitosan supported copper-based complex. The heterogeneous oxidative coupling catalyst has a structure as shown in a formula II: # imgabs0 #, and X is halogen, preferably Cl, Br or I. The modified chitosan supported copper-based complex is used as the catalyst of the oxidative coupling reaction, so that the problem that the catalyst cannot be recycled in the prior art is solved while the high yield is ensured, the reaction condition is mild, the product post-treatment method is simple, and the product purity is high.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for synthesizing 4,4'-biphenyl diquinone compounds and a method for preparing 4,4'-biphenyl diphenol. Background Art

[0002] 4,4'-Biphenylene glycol and its derivatives are an important class of compounds. They are widely present in biologically active molecules and are a class of valuable intermediates in the chemical and pharmaceutical industries. A large number of scientific experiments are devoted to studying various effective methods for synthesizing 4,4'-biphenylene glycol. For example, Tong Zhibiao, Geng Bin and others have successively used biphenyl sulfonation and hydrolysis to prepare 4,4'-biphenylene glycol. This process has the advantages of simple synthesis route and high yield, so it is widely used in industrial production, but a large amount of concentrated acid and strong base are consumed during the reaction process, causing great environmental pollution.

[0003] John H. Golbeck et al. used fungi to catalyze biphenyl to synthesize 4,4'-biphenyldiphenol in one step. Although the reaction steps are reduced, specific fungi need to be cultured in advance. This process is time-consuming and has high requirements for the culture environment. In addition, the fungi used in the experiment have poor selectivity and are easy to catalyze the production of various hydroxybiphenyls, resulting in a low yield of the target product. Therefore, this method is limited to laboratory synthesis and is difficult to promote industrialization.

[0004] Alessandro Prastaro et al. used scarce and expensive palladium complexes as catalysts, and used p-hydroxyphenylboronic acid and p-halogenphenol as substrates to undergo self-coupling or cross-coupling to generate 4,4'-biphenyldiphenol. Although metal catalysts have the characteristics of accelerating chemical reactions without participating in the final changes themselves, they will still be deactivated after repeated use. Given the scarce resources and high prices of catalysts for such reactions, such synthesis methods are not suitable for large-scale industrial production.

[0005] Takahashi Katsunori et al. studied the oxidative coupling of alkylphenols in the presence of oxidants such as oxygen or hydrogen peroxide, and then obtained biphenyl derivatives by dealkylation. However, due to the complex process and many reaction steps of this method, the final yield of the target product is directly affected. GWGray et al. used this reaction mechanism to diazotize and hydrolyze benzidine to obtain 4,4'-biphenyldiphenol. However, due to the instability of diazonium salts, the reaction needs to be carried out at low temperatures (below 5°C), and both benzidine and sodium nitrite are highly toxic, and diazonium salts are easy to decompose and explode, so it is not conducive to its promotion in industrial production.

[0006] Companies such as Dow Chemical in the United States and Mitsubishi in Japan mainly use 2,6-di-tert-butylphenol as raw material to prepare 4,4'-biphenylene glycol through three steps of oxidative coupling, reduction and dealkylation. However, the homogeneous catalyst in the reaction system is often unable to be recycled, resulting in waste of resources and environmental pollution. Therefore, it is of great significance to develop a new catalytic system for the simple and efficient synthesis of 4,4'-biphenylene glycol. Summary of the invention

[0007] In order to overcome the defects of traditional synthesis methods, the present invention provides a method for heterogeneously catalyzing the synthesis of 4,4'-diphenylquinone compounds, which overcomes the problem of catalyst recovery in the prior art, and has mild reaction conditions, simple product post-treatment method and high product purity.

[0008] The present invention has found that chitosan is cheap, easy to obtain, easy to functionalize, and easy to biodegrade. Chitosan has the characteristics of polyamine and hydroxyl structures. These structural characteristics not only make it alkaline, hydrophilic, and easy to degrade, but more importantly, it is easy to be chemically modified to graft more functional groups. Alkaline chitosan is conducive to the occurrence of oxidative coupling reactions. It is used as a carrier and modified by N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane to form a stable complex with monovalent copper. The formed modified chitosan-loaded copper complex has good catalytic activity.

[0009] The present invention finds that the modified chitosan-supported copper-based complex has high catalytic activity, and while ensuring high yield, overcomes the problem of catalyst being unable to be recycled in the prior art, and has mild reaction conditions, a simple product post-treatment method, and high product purity. In addition, the catalyst described in the present invention has good catalytic stability, is easy to recycle, and has good reusability.

[0010] To achieve the above-mentioned object, according to the first aspect of the present invention, a method for synthesizing 4,4'-diphenylquinone compounds is provided, the method comprising: in the presence of a heterogeneous oxidative coupling catalyst, a 2,6'-disubstituted phenol compound is subjected to an oxidative coupling reaction, and the reaction route is as shown in Formula I:

[0011]

[0012] Wherein, R1 and R2 are each independently a C1-C10 alkyl group, preferably a C3-C5 alkyl group, and more preferably a tert-butyl group;

[0013] The heterogeneous oxidative coupling catalyst is a modified chitosan-supported copper-based complex, and the heterogeneous oxidative coupling catalyst has a structure as shown in Formula II:

[0014]

[0015] Wherein, X is a halogen, preferably Cl, Br or I.

[0016] According to a second aspect of the present invention, the present invention provides a method for preparing 4,4'-biphenyldiphenol, the method comprising:

[0017] According to the method of the present invention, 3,3'5,5'-tetraalkylbiphenyldiquinone is synthesized by oxidative coupling reaction; then 3,3'5,5'-tetraalkylbiphenyldiphenol is obtained by hydrogenation reduction, and 4,4'-biphenyldiphenol is obtained by dealkylation and purification.

[0018] According to a third aspect of the present invention, the present invention provides a method for preparing 4,4'-biphenyl diphenol, which comprises the following steps: using 2,6-di-tert-butylphenol as a raw material, performing an oxidative coupling reaction according to the method described in any one of claims 1 to 4 to synthesize 3,3'5,5'-tetra-tert-butylbiphenyl diquinone; then performing hydrogenation reduction to obtain 3,3'5,5'-tetra-tert-butylbiphenyl diphenol, removing the tert-butyl group, and purifying to obtain 4,4'-biphenyl diphenol.

[0019] The present invention firstly finds that the alkalinity of chitosan is conducive to the oxidative coupling reaction, and the modified active component N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane is conducive to coordination with copper to form a stable complex.

[0020] Based on the above technical solution, the beneficial effects of the present invention are:

[0021] 1. The present invention proposes and synthesizes a novel modified chitosan-supported copper-based complex catalyst for oxidative coupling for the first time;

[0022] 2. The present invention uses a modified chitosan-supported copper-based complex as a catalyst for the oxidative coupling reaction, thereby ensuring a high yield and overcoming the problem of the catalyst being unable to be recovered in the prior art. The reaction conditions are mild, the product post-treatment method is simple, and the product purity is high.

[0023] 3. The chitosan-supported copper-based complex catalyst modified by the oxidative coupling reaction of the present invention has good catalytic stability, is easy to recycle and reuse, and has good reusability.

[0024] Through experimental comparison, it was found that when chitosan or N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane was used alone as the copper complex ligand, the product yield was low, while the product yield was significantly improved when chitosan modified with N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane was used as the ligand.

[0025] The method of the invention is simple to operate and the catalyst can be reused.

[0026] In the preparation of 4,4'-biphenol in the present invention, the modified chitosan-loaded copper complex is used as an oxidative coupling catalyst, and 4,4'-biphenol can be efficiently prepared through oxidative coupling, hydrogenation reduction and dealkylation, and has good industrial application prospects. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article 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 endpoint values ​​of each range, the endpoint values ​​of each range and the 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 as specifically disclosed in this article.

[0028] The present invention provides a method for synthesizing a 4,4'-diphenylquinone compound, which comprises: in the presence of a heterogeneous oxidative coupling catalyst, a 2,6'-disubstituted phenol compound undergoes an oxidative coupling reaction, and the reaction route is as shown in Formula I:

[0029]

[0030] Wherein, R1 and R2 are each independently a C1-C10 alkyl group, preferably a C3-C5 alkyl group, and more preferably a tert-butyl group;

[0031] The heterogeneous oxidative coupling catalyst is a modified chitosan-supported copper-based complex, and the heterogeneous oxidative coupling catalyst has a structure as shown in Formula II:

[0032]

[0033] Wherein, X is a halogen, preferably Cl, Br or I. The present invention uses a modified chitosan-supported copper-based complex as a catalyst for the oxidative coupling reaction, thereby ensuring a high yield and overcoming the problem that the catalyst cannot be recovered in the prior art, and the reaction conditions are mild, the product post-treatment method is simple, and the product purity is high.

[0034] In the present invention, any heterogeneous oxidative coupling catalyst having the aforementioned structure can be used in the present invention, and there is no special requirement for its preparation method or source. The following exemplary description is not intended to limit the scope of the present invention. According to one embodiment of the present invention, the preparation method of the heterogeneous oxidative coupling catalyst comprises:

[0035] (1) The active component N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane is dissolved in an aromatic hydrocarbon solvent, and then chitosan is added, heated to reflux, cooled to room temperature, filtered, and vacuum dried to obtain modified chitosan;

[0036] (2) Dissolving the modified chitosan in a polar solvent, adding copper salt under an inert gas atmosphere,

[0037] Stir at room temperature, filter, wash, and vacuum dry;

[0038] In the present invention, the amount of N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane and chitosan can be selected in a wide range, for example, the mass ratio of N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane to chitosan is 1:1 to 5, preferably 1:2 to 3; 1:2 is used as an exemplary illustration in the embodiments, but the scope of the present invention is not limited thereby.

[0039] In the present invention, chitosan has a wide range of options, and all can be used in the present invention. In the embodiments of the present invention, chitosan with a molecular weight of 100,000-300,000 is used as an example to illustrate the advantages of the present invention.

[0040] In the present invention, any aromatic hydrocarbon solvent can be used in the present invention, for example, it can be toluene.

[0041] In the present invention, the amount of the aromatic hydrocarbon solvent can be selected in a wide range, which is exemplary but not intended to limit the scope of the present invention. Preferably, the amount of the aromatic hydrocarbon solvent is 10-20 mL / g N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane, and more preferably, the amount of the aromatic hydrocarbon solvent is 12-15 mL / g N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane.

[0042] In the present invention, the polar solvent may be selected from a wide range of types, for example, one or more selected from DMF, DMA and DMSO.

[0043] In the present invention, the amount of the polar solvent can be selected in a wide range, which is exemplary but not intended to limit the scope of the present invention. For the present invention, the amount of the polar solvent is preferably 5-20 mL / g modified chitosan, and more preferably 8-12 mL / g modified chitosan.

[0044] In the present invention, the amount of modified chitosan and copper salt can be selected in a wide range, for example, the mass ratio of the two is 1:0.1-10, more preferably 1:0.5-2. In the embodiment, 1:1 is used as an example to illustrate the advantages of the present invention, but the scope of the present invention is not limited thereto.

[0045] In the present invention, the copper salt has a wide range of optional types. For the present invention, the copper salt is preferably selected from one or more of cuprous chloride, cuprous bromide and cupric iodide.

[0046] In the present invention, the conditions for heating to reflux include: heating to the boiling point of the aromatic hydrocarbons to be used and maintaining the reflux state.

[0047] In the present invention, the vacuum drying conditions can be selected in a wide range, for example, including: drying at 40-60° C. for 8-20 h under negative pressure.

[0048] According to one embodiment of the present invention, the vacuum drying conditions include: the material is placed under negative pressure and heated at 50° C. for 12 hours.

[0049] According to one embodiment of the present invention, step (2) comprises: adding an appropriate amount of modified chitosan to a polar solvent, adding an appropriate amount of monovalent copper salt under an inert gas atmosphere, stirring at room temperature for 12 hours, filtering, washing, and vacuum drying.

[0050] In the present invention, the inert atmosphere can be selected from a wide range, and commonly used inert atmospheres can be used in the present invention. For the present invention, for example, the inert atmosphere is a nitrogen atmosphere.

[0051] In the present invention, the amount of the heterogeneous oxidative coupling catalyst can be selected in a wide range and can be selected based on specific needs. According to one embodiment of the present invention, the amount of the heterogeneous oxidative coupling catalyst is 10 to 20 wt % of the raw material.

[0052] In the present invention, there is no special requirement for the oxidative coupling reaction oxidant, and it can be a commonly used oxidant, for example, selected from air and / or pure oxygen.

[0053] The present invention has no special requirements on the oxidative coupling reaction temperature, for example, 25°C to 80°C.

[0054] In the present invention, the organic solvent type used in the oxidative coupling reaction can be selected from a wide range, such as one or more of propylene carbonate, methylene chloride, xylene, ethyl acetate and methanol, but is not limited to the above solvent types. According to a preferred embodiment of the present invention, the organic solvent preferably contains at least ethyl acetate, more preferably a mixture of ethyl acetate and propylene carbonate, and any one of which is not less than 30 volume %, preferably not less than 40 volume %. Thus, the product yield can be further improved.

[0055] In the present invention, the amount of the organic solvent can be selected in a wide range, and any commonly used amount of the organic solvent can be used in the present invention, for example, the amount of the organic solvent is 10-50 ml / g 2,6'-disubstituted phenol compound, and more preferably the amount of the organic solvent is 20-40 ml / g 2,6'-disubstituted phenol compound.

[0056] In the present invention, the gas flow rate of the oxidative coupling reaction can be determined according to the operation requirements. For exemplary explanation, but not limiting the scope of the present invention, the gas flow rate of the oxidative coupling reaction is 0.1-1 mL / min, preferably 0.3-0.5 mL / min.

[0057] According to one embodiment of the present invention, the present invention provides a method for preparing 4,4'-biphenyl diphenol, which comprises: synthesizing 3,3'5,5'-tetraalkylbiphenyl diquinone by oxidative coupling reaction according to the method described in the present invention; then hydrogenating and reducing to obtain 3,3'5,5'-tetraalkylbiphenyl diphenol, removing the alkyl group, and purifying to obtain 4,4'-biphenyl diphenol.

[0058] According to one embodiment of the present invention, a method for preparing 4,4'-biphenyl diphenol is provided, and the method comprises the following steps: using 2,6-di-tert-butylphenol as a raw material, performing an oxidative coupling reaction according to the method described in the present invention to synthesize 3,3'5,5'-tetra-tert-butylbiphenyl diquinone; then performing hydrogenation reduction to obtain 3,3'5,5'-tetra-tert-butylbiphenyl diphenol, removing the tert-butyl group, and purifying to obtain 4,4'-biphenyl diphenol.

[0059] According to one embodiment of the present invention, purification is performed using solvent crystallization and / or sublimation.

[0060] In the present invention, commonly used solvent crystallization and sublimation can be applied to the present invention, specifically for example

[0061] The sublimation operating conditions include: heating and stirring the crude 4,4'-biphenol product under vacuum conditions; after the temperature reaches 180-220°C, using the temperature difference to bring the product to the desublimation device.

[0062] Specifically, for example, methanol is used to recrystallize the product for purification; the operating conditions include: under heating conditions, the crude 4,4'-biphenol product is mixed and dissolved with methanol, after the dissolution is completed, the heating is stopped, the solution is naturally cooled to precipitate crystals, after the crystals are precipitated, the solution and the crystals are separated, and the crystals are vacuum dried.

[0063] Specifically, for example, 10 grams of crude 4,4'-biphenol is added to a flask, and then an appropriate amount of methanol solution is added, the beaker is heated to make the methanol solution boil, the solid matter is completely dissolved, the heating is stopped, and the solution is cooled naturally to precipitate crystals. After the crystals are precipitated, the solution and the crystals are separated, and the crystals are vacuum dried.

[0064] According to a preferred embodiment of the present invention, the solvent is crystallized and then purified by sublimation, thereby obtaining a high-purity polymerization-grade product. According to a preferred embodiment of the present invention, the crude 4,4'-biphenol is vacuum sublimated and then enters the desublimation stage. The desublimation stage includes four desublimation stages, the first desublimation stage, the second desublimation stage, the third desublimation stage and the fourth desublimation stage. The temperature of the first desublimation stage is 160-170°C, the temperature of the second desublimation stage is 130-140°C, the temperature of the third desublimation stage is 100-110°C, and the temperature of the fourth desublimation stage is 80-110°C.

[0065] The purpose of the present invention can be achieved by satisfying the above conditions. For the present invention, the sublimation temperature is preferably 180-220°C, preferably 200-200°C;

[0066] According to a more preferred embodiment of the present invention, the temperature of the first desublimation stage is more preferably 20-30°C lower than the sublimation temperature, and the temperature difference between two adjacent desublimation stages of the first three desublimation stages is 20-30°C.

[0067] The method of the present invention has no special requirements for hydrogenation reduction. The following is an exemplary description, but the scope of the present invention is not limited thereto. The hydrogenation reduction catalyst is, for example, Pd / Al2O3.

[0068] The method of the present invention, the hydrogenation reduction operating conditions include, for example: the solvent is dichloromethane, and / or the reducing gas is a hydrogen-containing atmosphere, and / or the temperature is 60-80° C., and / or the pressure is 1-2 MPa, and / or the amount of the solvent is 10-50 mL / g of raw material, preferably 20-40 mL / g of raw material, and / or the amount of the catalyst is 10-30 wt% of the amount of the raw material.

[0069] Specifically, for example, the operating conditions include: adding an appropriate amount of hydrogenation reduction catalyst, 3,3'5,5'-tetra-tert-butyldiphenylquinone and dichloromethane solvent into a high-pressure reactor, introducing hydrogen and heating to a specified temperature to react.

[0070] In the present invention, there is no special requirement for the method of removing alkyl. The following is an exemplary description, but it does not limit the scope of the present invention. Specifically, for example, to remove alkyl or tert-butyl: the catalyst is p-toluenesulfonic acid, under an inert atmosphere, the solvent is an aromatic hydrocarbon, preferably an aromatic hydrocarbon, preferably xylene, and / or the amount of the solvent is 2-20mL / g of raw material, preferably 5-8mL / g of raw material, and / or the amount of the catalyst is 10-60wt% of the raw material, preferably 40-50wt%; and / or the temperature is 130-150°C, and / or the time is 4-6h. Specifically, for example, 3,3'5,5'-tetra-tert-butylbiphenol is added with an aromatic solvent and a p-toluenesulfonic acid catalyst, an inert gas is introduced, stirred at 140°C, and after reacting for 6 hours, the solid is filtered out to obtain a crude product.

[0071] According to a preferred embodiment of the present invention, to remove the alkyl or tert-butyl group, the catalyst comprises a mixture of a first ionic liquid containing a group shown in the following formula II in the molecule and a second ionic liquid containing a group shown in the following formula III in the molecule:

[0072] OTf refers to trifluoromethanesulfonyl;

[0073] The present invention uses double salt acidic ionic liquid as the catalyst for the dealkylation reaction, which can ensure high yield and high purity.

[0074] In the present invention, the dosage of the first ionic liquid [HO3S-(CH2)3-mim][OTf] and the second ionic liquid [HO3S-CH2Ph-mim][HSO4] can be selected in a wide range, and their compound use can achieve the purpose of the present invention. According to a preferred embodiment of the present invention, the molar ratio of the first ionic liquid [HO3S-(CH2)3-mim][OTf] and the second ionic liquid [HO3S-CH2Ph-mim][HSO4] is 1:1 to 1:10, preferably 1:3 to 1:5. Within the aforementioned preferred range, high yield and purity can be guaranteed.

[0075] In the present invention, the amount of catalyst used to remove the alkyl or tert-butyl group is relatively wide, and the commonly used amount of catalyst can achieve the purpose of the present invention. For the present invention, the amount of catalyst used is preferably 0.5-10wt%, preferably 1-3wt%, of the compound shown in Formula I. Within the above preferred range, high yield and purity can be guaranteed.

[0076] In the present invention, the operating conditions for removing the alkyl or tert-butyl group are relatively wide, and commonly used conditions can be used in the present invention. For the present invention, the preferred operating conditions include: a temperature of 130° C. to 230° C., preferably 180° C. to 210° C. Within the aforementioned preferred range, high yield and purity can be guaranteed.

[0077] In the present invention, the organic solvent used to remove the alkyl or tert-butyl group can be selected from a wide range of types, and all commonly used organic solvents can be used in the present invention. The following exemplary description is given, but the scope of the present invention is not limited thereto. The organic solvent used to remove the alkyl or tert-butyl group is one or more of propylene carbonate, mesitylene, xylene, kerosene, white oil, and C10-C18 alkanes.

[0078] In the present invention, the amount of organic solvent used to remove the alkyl or tert-butyl group can be selected in a wide range, which is exemplified below but does not limit the scope of the present invention. The mass concentration ratio of the organic solvent used for dealkylation to the compound represented by Formula I is 1-2 mL / g.

[0079] In the present invention, the dealkylation reaction is usually carried out under the protection of an inert gas at normal pressure.

[0080] The method of the present invention further comprises washing and decolorizing the dealkylation reaction product before performing the purification.

[0081] The method of the present invention has no special requirements for the steps of washing and decolorization, and can be carried out by methods of the prior art. The following is an exemplary description, but the scope of the present invention is not limited thereto. The preferred decolorization method is activated carbon adsorption.

[0082] In the present invention, 2,6-di-tert-butylphenol is used as a raw material as an example, and an oxidative coupling reaction is performed to synthesize 3,3'5,5'-tetra-tert-butyldiphenylquinone. The reaction route is as shown in formula (1), the hydrogenation reduction reaction route is as shown in formula (2), and the tert-butyl group is removed to obtain 4,4'-biphenyl diphenol. The reaction route is as shown in formula (3):

[0083]

[0084]

[0085] (4,4'-Biphenylenediphenol)

[0086] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the present invention is described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0087] The present invention will be described in detail below through examples. In the following examples, the conversion rate of the raw materials and the product yield parameters are obtained by liquid chromatography and calculated; the 2,6-di-tert-butylphenol raw material is a commercial product with a brand number of BD17932 from Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0088] The conversion rate is calculated as (mass of raw materials before reaction - mass of raw materials after reaction) / mass of raw materials before reaction * 100%, and the yield is calculated as mass of actual product / mass of theoretical product * 100%.

[0089] The synthesis of the modified chitosan-supported copper-based complex used in the following examples is as follows:

[0090] N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane (1.5 g) was dissolved in toluene (20 mL), and then dropped into a flask containing chitosan (3.0 g), heated under reflux at 110°C with stirring for 24 h, cooled to room temperature, filtered, and vacuum dried (50°C, 12 h) to obtain modified chitosan; the modified chitosan (2.0 g) was dissolved in polar solvent DMF (20 mL), 2 g of cuprous bromide was added under a nitrogen atmosphere, stirred at room temperature for 12 h, filtered, washed, and vacuum dried (50°C, 12 h).

[0091] The synthesis of the chitosan-supported copper-based complex used in the following Comparative Example 1 is as follows:

[0092] Chitosan (2.0 g) was dissolved in polar solvent DMF (20 mL), and 2 g of cuprous bromide was added under nitrogen atmosphere. The mixture was stirred at room temperature for 12 h, filtered, washed, and dried in vacuo.

[0093] In the following Comparative Example 2, CuCl / N-(2-aminoethyl)-3-aminopropyltriethoxysilane is used: a mixture of CuCl and N-(2-aminoethyl)-3-aminopropyltriethoxysilane, with a mass ratio of 1:1.

[0094] In the present invention, the chitosan brand is J&K 594839, the molecular weight is 100000-300000, and it is purchased from Beijing Bailingwei Technology Co., Ltd.

[0095] The yields of the following steps all refer to the yields of the corresponding individual steps.

[0096] The vacuum sublimation of the embodiment of the present invention is carried out in a vacuum sublimation device, which is a hollow structure, and its interior is divided into five areas with different heating temperatures, namely, a sublimation area, a collection area 1 (a first condensation area), a collection area 2 (a second condensation area), a collection area 3 (a third condensation area), a collection area 4 (a fourth condensation area) and a buffer area, and the buffer area is connected to a vacuum pump, and the vacuum pump evacuates the entire heating area and the buffer area. The vacuum sublimation device is made of quartz glass.

[0097] In the following embodiments, the solvent crystallization step includes: mixing and dissolving crude 4,4'-biphenol with methanol under heating conditions, stopping heating after dissolution is completed, and allowing the solution to cool naturally to precipitate crystals, separating the solution and the crystals after precipitation, and vacuum drying the crystals.

[0098] Example 1 Oxidative coupling reaction catalyzed by modified chitosan-supported copper-based complex

[0099] 2,6-di-tert-butylphenol (10 g), modified chitosan-supported copper-based complex (1 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.3 mL / min), and the reaction was carried out at room temperature of 25 ° C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone. The catalyst was recovered and reused after simple filtration, washing, and drying.

[0100] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 96%.

[0101] Comparative Example 1 Chitosan-supported copper-based complex catalyzes oxidative coupling reaction

[0102] 2,6-di-tert-butylphenol (10 g), chitosan-loaded copper complex (1 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.3 mL / min), and the reaction was carried out at room temperature of 25°C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone.

[0103] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 33%.

[0104] Comparative Example 2 Oxidative Coupling Reaction Catalyzed by CuCl / N-(2-aminoethyl)-3-aminopropyltriethoxysilane

[0105] 2,6-di-tert-butylphenol (10 g), catalyst CuCl / N-(2-aminoethyl)-3-aminopropyltriethoxysilane (1 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.3 mL / min), and the reaction was carried out at room temperature of 25°C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone.

[0106] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 61%.

[0107] Example 2

[0108] 2,6-di-tert-butylphenol (10 g), modified chitosan-supported copper-based complex (1 g), and methanol (300 mL) were added to a 500 mL reaction bottle, and air (0.3 mL / min) was introduced. The reaction was allowed to proceed at room temperature of 25 ° C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone. The catalyst was recovered and reused after simple filtration, washing, and drying.

[0109] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 88%.

[0110] Example 3

[0111] 2,6-di-tert-butylphenol (10 g), modified chitosan-supported copper complex (2 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.3 mL / min), and the reaction was carried out at room temperature of 25 ° C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone. The catalyst was recovered and reused after simple filtration, washing, and drying.

[0112] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 96%.

[0113] Example 4

[0114] 2,6-di-tert-butylphenol (10 g), modified chitosan-supported copper complex (1 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.1 mL / min), and the reaction was carried out at room temperature of 25 ° C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetra-tert-butyl-4,4'-diphenylquinone. The catalyst was recovered and reused after simple filtration, washing, and drying.

[0115] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 75%.

[0116] Example 5

[0117] 2,6-diethylphenol (10 g), modified chitosan-supported copper complex (1 g), ethyl acetate (300 mL) were added to a 500 mL reaction bottle, air was introduced (0.2 mL / min), and the reaction was carried out at room temperature of 25 ° C for 12 hours. After the reaction was completed, water was added to quench the reaction, and the organic phase was separated and concentrated to obtain dark red 3,3',5,5'-tetraethyl-4,4'-diphenylquinone. The catalyst was recovered and reused after simple filtration, washing, and drying.

[0118] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 80%.

[0119] Example 6

[0120] The method of Example 1 is followed, except that the solvent is a mixture of vinyl acetate and propylene carbonate, and the volume ratio of the two is 1:1, and the total amount of the two is 300 mL.

[0121] Analysis by liquid chromatography showed that the reaction conversion rate was 100% and the yield was 98%.

[0122] Example 7

[0123] Preparation of 4,4'-biphenylene glycol:

[0124] Using 2,6-di-tert-butylphenol as a raw material, an oxidative coupling reaction was performed according to the method of Example 1 to synthesize 3,3'5,5'-tetra-tert-butyldiphenylquinone;

[0125] Then, hydrogen reduction is performed to obtain 3,3'5,5'-tetra-tert-butylbiphenol, and the tert-butyl group is removed and purified to obtain 4,4'-biphenol.

[0126] Hydrogenation reduction: 3,3'5,5'-Tetra-tert-butyldiphenylquinone (5 g), CH2Cl2 (150 mL), and a hydrogenation catalyst (Pd / Al2O3, pt loading 4 wt%, 1 g) were added to a high-pressure reactor in sequence, and then H2 (1.6 MPa) was introduced and reacted at 70°C for 12 h. After the reaction was completed, the solution was filtered and dried to obtain a bright yellow solid 3,3'5,5'-tetra-tert-butyldiphenol with a yield of 97.12%.

[0127] Dealkylation:

[0128] 3,3',5,5'-tetra-tert-butylbiphenol (100 g), p-toluenesulfonic acid (1 g), and C18 alkane (100 mL) were added to a 500 mL reaction bottle in sequence, and N2 was introduced. The reaction was carried out at 180°C under normal pressure for 3 hours. After the reaction was completed, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, decolorized with activated carbon, and recrystallized to obtain crude 4,4'-biphenol.

[0129] Analysis by liquid chromatography showed that the reaction yield was 32% and the purity was 85%.

[0130] Example 8

[0131] The method of Example 7 is followed, except that

[0132] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0133] 3,3',5,5'-tetra-tert-butylbiphenol (100g), double hydrochloric acidic ionic liquid (1g) with a molar ratio of [HO3S-(CH2)3-mim][OTf] to [HO3S-CH2Ph-mim][HSO4] of 1:3 as catalyst, n-C18 alkane (100mL), N2 was introduced, and the reaction was carried out at 180°C for 3 hours under normal pressure. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, and the crude product of 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0134] Analysis by liquid chromatography showed that the reaction yield was 88% and the purity was 96%.

[0135] Example 9

[0136] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0137] 3,3',5,5'-tetra-tert-butylbiphenol (100g), double hydrochloric acid ionic liquid (1g) with a molar ratio of [HO3S-(CH2)3-mim][OTf] to [HO3S-CH2Ph-mim][HSO4] of 1:3 as catalyst, n-C18 alkane (100mL), N2 was introduced, and the reaction was carried out at 220°C for 3 hours. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, and the crude product of 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0138] Analysis by liquid chromatography showed that the reaction yield was 77% and the purity was 91%.

[0139] Example 10

[0140] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0141] 3,3',5,5'-tetra-tert-butylbiphenol (100g), double hydrochloric acid ionic liquid (2g) with a molar ratio of [HO3S-(CH2)3-mim][OTf] to [HO3S-CH2Ph-mim][HSO4] of 1:2 as catalyst, n-C18 alkane (100mL), N2 was introduced, and the reaction was carried out at 180°C for 3 hours. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol (the solid product was dissolved for the next step of activated carbon decolorization), and the crude product of 4,4'-biphenol was obtained by activated carbon decolorization and recrystallization, and the filtrate obtained was collected and recycled.

[0142] Analysis by liquid chromatography showed that the reaction yield was 82% and the purity was 88%.

[0143] Embodiment 11

[0144] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0145] 3,3',5,5'-tetra-tert-butylbiphenol (100g), double hydrochloric acidic ionic liquid (1g) with a molar ratio of [HO3S-(CH2)3-mim][OTf] to [HO3S-CH2Ph-mim][HSO4] of 1:1 as catalyst, n-C18 alkane (100mL), N2 was introduced, and the reaction was carried out at 180°C for 3 hours. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, and the crude product of 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0146] Analysis by liquid chromatography showed that the reaction yield was 66% and the purity was 89%.

[0147] Example 12

[0148] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0149] 3,3',5,5'-tetra-tert-butylbiphenol (100g), double hydrochloric acid ionic liquid (0.5g) with a molar ratio of [HO3S-(CH2)3-mim][OTf] to [HO3S-CH2Ph-mim][HSO4] of 1:3 as catalyst, n-C18 alkane (100mL), N2 was introduced, and the reaction was carried out at 180°C for 3 hours. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, and the crude product of 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0150] Analysis by liquid chromatography showed that the reaction yield was 68% and the purity was 90%.

[0151] Embodiment 13

[0152] [HO3S-(CH2)3-mim][OTf]-catalyzed dealkylation

[0153] 3,3',5,5'-tetra-tert-butylbiphenol (100 g), catalyst [HO3S-CH2Ph-mim][HSO4] (1 g), C18 alkane (100 mL) were added to a 500 mL reaction bottle in sequence, N2 was introduced, and the reaction was carried out at 180°C under normal pressure for 3 hours. After the reaction was completed, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, decolorized with activated carbon, and recrystallized to obtain crude 4,4'-biphenol.

[0154] Analysis by liquid chromatography showed that the reaction yield was 37% and the purity was 87%.

[0155] Embodiment 14

[0156] [HO3S-CH2Ph-mim][HSO4] catalytic dealkylation

[0157] 3,3',5,5'-tetra-tert-butylbiphenol (100 g), catalyst [HO3S-(CH2)3-mim][OTf] (1 g), C18 alkane (100 mL) were added to a 500 mL reaction bottle in sequence, N2 was introduced, and the reaction was carried out at 180°C under normal pressure for 3 hours. After the reaction was completed, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, decolorized with activated carbon, and recrystallized to obtain crude 4,4'-biphenol.

[0158] Analysis by liquid chromatography showed that the reaction yield was 57% and the purity was 82%.

[0159] Embodiment 15

[0160] Take 50 g of crude 4,4'-biphenol (initial HPLC purity 91%, from Example 9) and place it in a vacuum sublimation device. Turn on the vacuum pump until the vacuum degree reaches 5*10 -3 Pa, the sublimation tube area is heated to 200°C, the collection tube area 1 is heated to 170°C, the collection tube area 2 is heated to 140°C, the collection tube area 3 is heated to 110°C, and the collection tube area 4 is heated to 110°C. Keep warm until no substance condenses, then lower the temperature to room temperature, break nitrogen gas into the air, and collect white solid 4,4'-biphenol in each collection tube area. The product purity is 99.6%, and the content of organic polymer impurities is 180ppm.

[0161] Example 16

[0162] Take 50 g of crude 4,4'-biphenol (initial HPLC purity 91%, from Example 9) and place it in a vacuum sublimation device. Turn on the vacuum pump until the vacuum degree reaches 5*10 -3 Pa, the sublimation tube area is heated to 200°C, the collection tube area 1 is heated to 170°C, the collection tube area 2 is heated to 140°C, the collection tube area 3 is heated to 110°C, and the collection tube area 4 is heated to 80°C. Keep warm until no substance condenses, then lower the temperature to room temperature, break nitrogen gas into the air, and collect white solid 4,4'-biphenol in each collection tube area. The product purity is 99.4%, and the content of organic polymer impurities is 200ppm.

[0163] The crude products of the remaining examples were purified by sublimation using the method of Examples 15-16, and the purity of the products was able to reach more than 99%.

[0164] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0165] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for synthesizing 4,4'-diphenylquinone compounds, characterized in that: The method comprises: in the presence of a heterogeneous oxidative coupling catalyst, a 2,6-disubstituted phenol compound undergoes an oxidative coupling reaction, and the reaction route is as shown in Formula I: Wherein, R1 and R2 are each independently a C1-C10 alkyl group, preferably a C3-C5 alkyl group, and more preferably a tert-butyl group; The heterogeneous oxidative coupling catalyst is a modified chitosan-supported copper-based complex, and the heterogeneous oxidative coupling catalyst has a structure as shown in Formula II: Wherein, X is a halogen, preferably Cl, Br or I.

2. The synthesis method according to claim 1, wherein The preparation method of the heterogeneous oxidative coupling catalyst comprises: (1) The active component N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane is dissolved in an aromatic hydrocarbon solvent, and then chitosan is added, heated to reflux, cooled to room temperature, filtered, and vacuum dried to obtain modified chitosan; (2) dissolving the modified chitosan in a polar solvent, adding copper salt under an inert gas atmosphere, stirring at room temperature, filtering, washing, and vacuum drying; The conditions of step (1) include: the mass ratio of N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane to chitosan is 1:1-5, preferably 1:2-3; The aromatic hydrocarbon solvent is selected from toluene, and the aromatic hydrocarbon solvent is preferably used in an amount of 10-20 mL / g N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane, and more preferably in an amount of 12-15 mL / g N-(2-N,N-dimethylethyl)-3-aminopropyltriethoxysilane; The polar solvent is selected from one or more of DMF, DMA and DMSO, preferably the amount of the polar solvent is 5-20 mL / g modified chitosan, more preferably the amount of the polar solvent is 8-12 mL / g modified chitosan; The mass ratio of modified chitosan to copper salt is 1:0.1-10, more preferably 1:0.5-2; The copper salt is selected from one or more of cuprous chloride, cuprous bromide and cupric iodide; The vacuum drying conditions include: drying at 40-60°C for 8-20 hours under negative pressure.

3. The synthesis method according to claim 1 or 2, wherein The amount of the heterogeneous oxidative coupling catalyst used is 10-20 wt % of the raw material.

4. The synthesis method according to any one of claims 1 to 3, wherein The oxidative coupling reaction oxidant is selected from air and / or pure oxygen; and / or The oxidative coupling reaction temperature is 25°C to 80°C; and / or The organic solvent used in the oxidative coupling reaction is one or more of propylene carbonate, dichloromethane, xylene, ethyl acetate and methanol, preferably the organic solvent contains at least ethyl acetate, more preferably a mixture of ethyl acetate and propylene carbonate, and the content of any one of them is not less than 30% by volume, preferably not less than 40% by volume; and / or The amount of the organic solvent used is 10-50 ml / g 2,6-disubstituted phenol compound, preferably the amount of the organic solvent used is 20-40 ml / g 2,6-disubstituted phenol compound; The gas flow rate of the oxidative coupling reaction is 0.1 to 1 mL / min, preferably 0.3 to 0.5 mL / min.

5. A method for preparing 4,4'-biphenyl diphenol, the method comprising: Synthesize 3,3'5,5'-tetraalkyldiphenylquinone by oxidative coupling reaction according to the method described in any one of claims 1 to 4; Then, hydrogen reduction is performed to obtain 3,3'5,5'-tetraalkylbiphenol, and the alkyl group is removed and purified to obtain 4,4'-biphenol.

6. A method for preparing 4,4'-biphenyl diphenol, characterized in that: The method comprises the following steps: using 2,6-di-tert-butylphenol as a raw material, carrying out an oxidative coupling reaction according to the method described in any one of claims 1 to 4 to synthesize 3,3'5,5'-tetra-tert-butylbiphenyl diquinone; then performing hydrogenation reduction to obtain 3,3'5,5'-tetra-tert-butylbiphenyl diphenol, removing the tert-butyl group, and purifying to obtain 4,4'-biphenyl diphenol.

7. The preparation method according to claim 5 or 6, wherein: Purification is performed using solvent crystallization and / or sublimation, with operating conditions including: The sublimation steps include: heating and stirring the crude 4,4'-biphenol under vacuum conditions; after the temperature reaches 180-220°C, using the temperature difference to bring the product to a desublimation device; The steps of solvent crystallization include: Under heating conditions, the crude 4,4'-biphenol is mixed with methanol and dissolved. After the dissolution is completed, the heating is stopped, and the solution is cooled naturally to precipitate crystals. After the crystals are precipitated, the solution and the crystals are separated, and the crystals are vacuum dried.

8. The preparation method according to claim 5 or 6, wherein: The sublimation step comprises: vacuum sublimating the crude 4,4'-biphenol, and then entering the desublimation stage, the desublimation stage comprises four desublimation stages, the first desublimation stage, the second desublimation stage, the third desublimation stage and the fourth desublimation stage, the temperature of the first desublimation stage is 160-170°C, the temperature of the second desublimation stage is 130-140°C, the temperature of the third desublimation stage is 100-110°C, and the temperature of the fourth desublimation stage is 80-110°C; preferably, the sublimation temperature is 180-220°C, preferably 200-200°C; More preferably, the temperature of the first desublimation stage is 20-30°C lower than the sublimation temperature, and the temperature difference between two adjacent desublimation stages in the first three desublimation stages is 20-30°C.

9. The preparation method according to claim 5 or 6, wherein: In hydrogenation reduction, The hydrogenation reduction catalyst is Pd / Al2O3; and / or The solvent is dichloromethane; and / or The reducing gas is a hydrogen-containing atmosphere; and / or The temperature is 60-80°C; and / or The pressure is 1-2MPa; and / or The amount of solvent used is 10-50 mL / g raw material, preferably 20-40 mL / g raw material; and / or The amount of catalyst used is 10-30wt% of the amount of raw materials used.

10. The preparation method according to claim 5 or 6, wherein: To remove alkyl or tert-butyl groups: The catalyst comprises a mixture of a first ionic liquid having a group represented by the following formula II in its molecule and a second ionic liquid having a group represented by the following formula III in its molecule: OTf refers to trifluoromethanesulfonyl; Preferably, the molar ratio of the first ionic liquid [HO3S-(CH2)3-mim][OTf] to the second ionic liquid [HO3S-CH2Ph-mim][HSO4] is 1:1 to 1:10, preferably 1:3 to 1:5; The amount of the catalyst used is 0.5-10 wt % of the compound represented by formula I, preferably 1-3 wt %; The operating conditions include: a temperature of 130°C to 230°C, preferably 180°C to 210°C; The organic solvent used for dealkylation is one or more of propylene carbonate, mesitylene, xylene, kerosene, white oil, and C10-C18 alkane; The mass concentration ratio of the organic solvent used in the dealkylation to the compound represented by Formula I is 1-2 mL / g; The dealkylation reaction is carried out under the protection of an inert gas at normal pressure.

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