Preparation method of 4, 4 '-biphenol compound

Abstract

The invention provides a method for preparing 4, 4 '-biphenol through dealkylation reaction, which comprises the following steps: in the presence of a catalyst, dealkylating a compound shown as a formula I to obtain 4, 4'-biphenol: # imgabs0 #, in which Ra, Rc, Rd and Re are independently C1-C10 alkyl groups; the compound hydrochloric acid ionic liquid is used as the catalyst of the dealkylation reaction, so that high yield and high purity can be ensured, and the problems of large catalyst dosage and incapability of recycling in the prior art are solved.

Description

Technical Field

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

[0002] 4,4'-Biphenylene and its derivatives are an important class of compounds and are valuable intermediates in the chemical and pharmaceutical industries. Allan S. Hay et al. studied the dealkylation of 3,3',5,5'-tetrabutylbiphenylene as a raw material, isopropyl aluminum salt as a catalyst, and tert-butylphenol as a solvent to obtain biphenyl derivatives. However, since the isobutylene removed by this method easily reacts with the benzene ring of the solvent, the isobutylene recovery rate is low, the solvent deteriorates, and the dealkylation temperature is relatively high.

[0003] Mitsubishi Petrochemical Company of Japan has developed an acidic catalyst that uses alkane solvents or cyclopentane solvents to avoid the problem of isobutylene addition to the solvent and improve the purity of the product. However, the reaction needs to be carried out under pressurized conditions, the reaction apparatus is complex, and extremely high requirements are placed on the equipment.

[0004] Mitsubishi Petrochemical Company of Japan has studied the dealkylation reaction in the presence of water or low-carbon alcohols. Although water or low-carbon alcohols can enhance the dispersion of the catalyst and improve the yield and purity of the product, it is necessary to first oxidize 3,3',5,5'-tetrabutylbiphenol to a diphenylquinone compound and then react with 2,6-di-tert-butylphenol, which undoubtedly increases the reaction process and makes the process more complicated. Summary of the invention

[0005] In order to solve the defects of the existing process synthesis, the present invention provides a method for preparing 4,4'-biphenyl diphenol, which has high yield, mild conditions, simple product post-treatment method and high product purity.

[0006] At present, the dealkylation process generally has problems such as the inability to recover catalysts and solvents and relatively high reaction temperatures. It is of great significance to develop a simple and efficient dealkylation catalytic system for the preparation of 4,4'-biphenol.

[0007] The present invention proposes for the first time that a double salt ionic liquid is used as a dealkylation catalyst. The acidity of the double salt acidic ionic liquid is conducive to the dealkylation reaction, and the length of the cationic alkyl chain has an important influence on the catalytic activity of the double salt ionic liquid. The synthesis method of the double salt acidic ionic liquid is: [HO3S-(CH2)3-mim][OTf] and [HO3S-CH2Ph-mim][HSO4] are directly physically mixed, and the catalytic activity can be regulated by adjusting the content of the two; the double salt ionic liquid has great advantages in adjusting physical and chemical properties and improving reaction selectivity, yield, activity, etc.

[0008] To achieve the above-mentioned object, the present invention provides a method for preparing 4,4'-biphenol by dealkylation reaction, the method comprising: in the presence of a catalyst, dealkylating a compound represented by formula I to obtain 4,4'-biphenol:

[0009]

[0010] Wherein, Ra, Rc, Rd and Re are independently C1-C10 alkyl groups, preferably tert-butyl groups;

[0011] 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:

[0012] OTf refers to trifluoromethanesulfonyl;

[0013]

[0014] According to a preferred embodiment of the present invention, the present invention uses 3,3',5,5'-tetrabutylbiphenol as a raw material, a double hydrochloric acidic ionic liquid as a catalyst, and an organic solvent as an option to directly remove the alkyl group to efficiently prepare 4,4'-biphenol, which has good prospects for industrial application.

[0015] The present invention finds that the catalyst of the present invention overcomes the problems of the catalyst being unable to be recycled and the large amount of catalyst used in the prior art, and has a high yield, mild conditions, a simple product post-processing method, and a high product purity. At the same time, the catalyst of the present invention has good catalytic stability, is easy to recycle and reuse, and has good reusability.

[0016] The present invention uses a double salt acidic ionic liquid as a catalyst for the dealkylation reaction, which can ensure high yield and high purity while overcoming the problem of large catalyst dosage and inability to recover in the prior art.

[0017] The catalyst of the present invention has good catalytic stability, is easy to recycle and reuse, and has good reusability. DETAILED DESCRIPTION

[0018] 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.

[0019] The present invention provides a method for preparing 4,4'-biphenol by dealkylation reaction, the method comprising: in the presence of a catalyst, dealkylating a compound shown in formula I to obtain 4,4'-biphenol:

[0020]

[0021] Wherein, Ra, Rc, Rd and Re are independently C1-C10 alkyl groups, and tert-butyl is used as an example to illustrate the advantages of the present invention;

[0022] 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:

[0023] OTf refers to trifluoromethanesulfonyl;

[0024] The present invention uses double salt acidic ionic liquid as the catalyst for the dealkylation reaction, which can ensure high yield and high purity.

[0025] 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.

[0026] In the present invention, the amount of catalyst can be selected in a wide range, and the commonly used amount of catalyst can achieve the purpose of the present invention. For the present invention, the amount of catalyst is preferably 0.5-10wt%, preferably 1-3wt% of the compound represented by formula I. Within the above preferred range, high yield and purity can be guaranteed.

[0027] In the present invention, the dealkylation operating conditions can be selected in a wide range, and commonly used dealkylation conditions can be used in the present invention. For the present invention, the dealkylation operating conditions preferably 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.

[0028] In the present invention, the optional range of organic solvent types used for dealkylation is relatively wide, and commonly used organic solvent types can be used in the present invention. The following exemplary description, but not limiting the scope of the present invention, the organic solvent used for dealkylation is one or more of propylene carbonate, mesitylene, xylene, kerosene, white oil, and C10-C18 alkanes.

[0029] In the present invention, the amount of the organic solvent can be selected in a wide range. The following is an exemplary description, but the scope of the present invention is not limited thereto. The mass concentration ratio of the organic solvent used in the dealkylation to the compound represented by Formula I is 1-2 mL / g.

[0030] In the present invention, the dealkylation reaction is usually carried out under the protection of an inert gas at normal pressure.

[0031] The method of the present invention further comprises washing, decolorizing and purifying the dealkylation reaction product.

[0032] The method of the present invention has no special requirements for the steps of washing, decolorization and purification, 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.

[0033] According to one embodiment of the present invention, purification is performed using solvent crystallization and / or sublimation.

[0034] In the present invention, there is no special requirement for the steps of sublimation and solvent crystallization, which are exemplarily described below, but the scope of the present invention is not limited thereby.

[0035] According to one embodiment of the present invention, preferably, the sublimation step comprises: heating and stirring the crude 4,4'-biphenol under vacuum conditions; the temperature reaches 180-220°C, and using the temperature difference to bring the product to a desublimation device.

[0036] According to one embodiment of the present invention, the sublimation step includes: vacuum sublimating the crude 4,4'-biphenol, and then entering 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; preferably, the sublimation temperature is 180-220°C, preferably 200-200°C; the above method can be used to purify and obtain a high-purity polymerization-grade product.

[0037] According to one 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 in the first three desublimation stages is 20-30° C. The above method can be used to purify a high-purity polymerization-grade product.

[0038] According to one embodiment of the present invention, the solvent crystallization step includes: under heating conditions, the crude 4,4'-biphenol 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.

[0039] According to a preferred embodiment of the present invention, a method for preparing 4,4'-biphenol is provided, comprising the following steps: using 3,3',5,5'-tetra-tert-butylbiphenol as a raw material and a double hydrochloric acid ionic liquid as a catalyst to synthesize 4,4'-biphenol, and the reaction route is as follows:

[0040]

[0041] The present invention will be described in detail below through examples. In the following examples, the conversion rate of raw materials and the product yield parameters are measured by liquid chromatography; the 3,3',5,5'-tetra-tert-butylbiphenol raw material is homemade in the laboratory.

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention is described clearly and completely below. 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. The calculation formula of the yield is the mass of the actual product / the mass of the theoretical product*100%.

[0043] The first ionic liquid and the second ionic liquid in the present invention are self-made products of the applicant.

[0044] 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.

[0045] 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.

[0046] Example 1

[0047] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0048] 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 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 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0049] Analysis by liquid chromatography showed that the reaction yield was 88% and the purity was 96%.

[0050] Comparative Example 1

[0051] [HO3S-(CH2)3-mim][OTf]-catalyzed dealkylation

[0052] 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 4,4'-biphenol.

[0053] Analysis by liquid chromatography showed that the reaction yield was 37% and the purity was 87%.

[0054] Comparative Example 2

[0055] [HO3S-CH2Ph-mim][HSO4] catalytic dealkylation

[0056] 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 4,4'-biphenol.

[0057] Analysis by liquid chromatography showed that the reaction yield was 57% and the purity was 82%.

[0058] Comparative Example 3

[0059] p-Toluenesulfonic acid-catalyzed dealkylation

[0060] 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 4,4'-biphenol.

[0061] Analysis by liquid chromatography showed that the reaction yield was 32% and the purity was 85%.

[0062] Example 2

[0063] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0064] 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 220°C for 3 hours. After the reaction, the reaction solution was filtered, and the solid obtained by filtration was dissolved in methanol, and 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0065] Analysis by liquid chromatography showed that the reaction yield was 77% and the purity was 91%.

[0066] Example 3

[0067] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0068] 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 4,4'-biphenol was obtained by activated carbon decolorization and recrystallization, and the filtrate was collected and recycled.

[0069] Analysis by liquid chromatography showed that the reaction yield was 82% and the purity was 88%.

[0070] Example 4

[0071] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0072] To a 500mL reaction bottle, add 3,3',5,5'-tetra-tert-butylbiphenol (100g), [HO3S-(CH2)3-mim][OTf] and [HO3S-CH2Ph-mim][HSO4] with a molar ratio of 1:1 double hydrochloric acid ionic liquid (1g) as a catalyst, and n-C18 alkane (100mL), introduce N2, and react at 180°C for 3 hours. After the reaction is completed, the reaction solution is filtered, and the solid obtained by filtration is dissolved in methanol, and 4,4'-biphenol can be obtained by decolorization with activated carbon and recrystallization. The filtrate obtained can be collected and recycled.

[0073] Analysis by liquid chromatography showed that the reaction yield was 66% and the purity was 89%.

[0074] Example 5

[0075] Dealkylation by [HO3S-(CH2)3-mim][OTf] / [HO3S-CH2Ph-mim][HSO4]

[0076] 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 4,4'-biphenol was obtained by decolorization with activated carbon and recrystallization. The filtrate obtained was collected and recycled.

[0077] Analysis by liquid chromatography showed that the reaction yield was 68% and the purity was 90%.

[0078] Example 6

[0079] Take 50 g of crude 4,4'-biphenol (initial HPLC purity 91%, from Example 2) and place it in a vacuum sublimation device. Turn on the vacuum pump until the vacuum degree reaches 5*10 -3Pa, 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.

[0080] Example 7

[0081] Take 50 g of crude 4,4'-biphenol (initial HPLC purity 91%, from Example 2) 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.

[0082] The crude products of the remaining examples and comparative examples were purified by sublimation using the method of Examples 6-7, and the purity of the products could reach more than 99%.

[0083] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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.

[0084] 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 preparing 4,4'-biphenol by dealkylation reaction, characterized in that: The method comprises: in the presence of a catalyst, dealkylating a compound shown in formula I to obtain 4,4'-biphenyl diphenol: Wherein, Ra, Rc, Rd and Re are independently C1-C10 alkyl groups, preferably 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; 2. The method according to claim 1, wherein: 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.

3. The method according to claim 1 or 2, wherein: The amount of the catalyst used is 0.5-10 wt % of the compound represented by formula I, preferably 1-3 wt %.

4. The method according to any one of claims 1 to 3, wherein: The dealkylation operation conditions include: a temperature of 130°C to 230°C, preferably 180°C to 210°C.

5. The method according to any one of claims 1 to 4, wherein: The organic solvent used for dealkylation is one or more of propylene carbonate, mesitylene, xylene, kerosene, white oil, and C10-C18 alkane.

6. The method according to any one of claims 1 to 5, wherein: The mass concentration ratio of the organic solvent used in the dealkylation to the compound represented by formula I is 1-2 mL / g.

7. The method according to any one of claims 1 to 6, wherein: The dealkylation reaction is carried out under the protection of an inert gas at normal pressure.

8. The method according to any one of claims 1 to 7, wherein: The method also includes washing, decolorizing and purifying the dealkylation reaction product; Purification is performed using solvent crystallization and / or sublimation; Preferably, the sublimation step comprises: heating the crude 4,4'-biphenol under vacuum conditions; After the temperature reaches 180-220℃, the temperature difference is used to bring the product to the desublimation device.

9. The method according to any one of claims 8, 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, namely, 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.

10. The method according to claim 8, wherein: The decolorization method is activated carbon adsorption; 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.

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