A method for separating and purifying 4,4'-biphenyl diphenol

Abstract

The present application relates to the technical field of separation and purification of high-end fine chemicals, and specifically to a method for separating and purifying 4,4'-biphenyldiphenol. The method is as follows: the crude product of the dealkylation reaction is subjected to the first solid-liquid separation; a fresh organic solvent or a saturated solvent is added to the obtained material, and the material is fully pulped and washed for the second solid-liquid separation; a hot solvent III is added to the obtained material, dissolved and mixed, and sent to a fixed bed for adsorption, and decolorization and metal ion removal are performed; the fixed bed is filled with a graded adsorbent; the material after adsorption and decolorization is sent to an evaporation crystallization unit, and the material is subjected to a third solid-liquid separation after evaporation and crystallization. After drying, the separated material obtains high-purity 4,4'-biphenyldiphenol. The present application uses a fixed bed, a graded loading adsorbent, and an evaporative crystallization process to separate and purify 4,4'-biphenyldiphenol to achieve low energy consumption, safety, low metal content, and large-scale production of 4,4'-biphenyldiphenol.

Description

Technical Field

[0001] The present application relates to the technical field of separation and purification of high-end fine chemicals, and in particular to a method for separating and purifying 4,4'-biphenyl diphenol. Background Art

[0002] 4,4'-Biphenol (also known as 4,4'-dihydroxybiphenyl, p-hydroxybiphenol, hereinafter referred to as LBP) is a key basic monomer for the synthesis of polyphenylene sulfone (PPSU). At present, all of it is imported, and it is the only key technical problem that needs to be solved in the entire PPSU industry chain. At the same time, 4,4'-biphenol is also a key basic raw material for electronic-grade thermotropic liquid crystal polymer (TLCP). Since TLCP is a polymer with the highest strength and modulus, it has a very small linear expansion coefficient, outstanding heat resistance and stability, excellent radiation resistance, weather aging resistance, flame retardancy and chemical corrosion resistance, and also has microwave transparency and optical, electrical, magnetic and separation functions. Therefore, TLCP has become an indispensable key raw material for strategic emerging industries such as electronic communications, aerospace, national defense and military. According to data, the application of TLCP in the electronic and electrical appliances and consumer electronics industries accounts for about 82%.

[0003] Based on the above, the industrialization of 4,4'-biphenol involves medical health and a number of strategic emerging industries. In recent years, policies and guidelines have been promulgated to "focus on the development of functional polymer materials, high-performance structural materials, etc., accelerate the research and development of key technologies and equipment for the preparation of new materials, and break through the bottleneck of industrial preparation" to provide full support.

[0004] At present, there are mainly the following methods for preparing 4,4'-biphenyl diphenol: benzidine method, biphenyl sulfonation alkali fusion method, biphenyl halogenation high-pressure hydrolysis method and phenol method.

[0005] Among them, the phenol method is the mainstream process route internationally. The specific process mainly includes: under the action of a catalyst, phenol and isobutylene generate 2,6-di-tert-butylphenol (alkylation unit). The latter is coupled to 3,3',5,5'-tetra-tert-butyl-4,4'-biphenylphenol and over-oxidation products (oxidation coupling unit) under the action of oxygen. Finally, isobutylene is released under the action of a catalyst to obtain a 4,4'-biphenylphenol product (debutylation unit); finally, the obtained 4,4'-biphenylphenol is separated and purified to obtain a high-purity finished product 4,4'-biphenylphenol (separation and purification unit). Its chemical equation is as follows:

[0006] .

[0007] As mentioned above, high-purity 4,4'-biphenol is not only a key basic monomer of PPSU, but more importantly, a key raw material of liquid crystal material TLCP. Therefore, higher requirements are placed on the separation and purification of crude 4,4'-biphenol after the debutylation reaction.

[0008] At present, there are relatively few public reports on the separation and purification of 4,4'-biphenyl diphenol, as follows:

[0009] The related technology discloses a method for preparing high-purity 4,4'-biphenol. The specific method of the separation and purification unit is to filter the reaction product, dissolve the filter cake obtained by filtration in a 50-60°C hot methanol solution containing activated carbon, and recrystallize the uniformly dissolved solution to finally obtain 4,4'-biphenol.

[0010] The related technology also discloses a method for purifying 4,4'-biphenol, and the specific method is to add crude 4,4'-biphenol to a solvent (such as methanol, ethanol, propanol, butanol, ethylene glycol, 1,2-propylene glycol) and heat to the dissolution temperature, stir until completely dissolved, then add a dilute acid solution with a concentration of 0.1 mol / L, and then add activated carbon for decolorization, keep warm for 30-60 minutes, cool and filter to remove the activated carbon, then cool to 27-30°C for crystallization and filtration, wash the solid phase with water, and dry to obtain purified 4,4'-biphenol.

[0011] In addition, the related technology also discloses a method for preparing biphenyl diphenol. The specific method is to obtain crude 4,4'-biphenyl diphenol by debutylation reaction, filter out the solid in the reaction system to obtain a crude product, add it to a methanol solution, heat it to dissolve it, add activated carbon for decolorization, filter out the activated carbon while hot, return the filtrate to the reactor, stir, cool and crystallize, and after the system temperature drops to room temperature, filter, wash and dry to obtain 4,4'-biphenyl diphenol with a purity of about 99.8wt.%.

[0012] Furthermore, the related art also discloses a method for preparing 4,4'-biphenol with a high yield. The specific method is to dissolve the dealkation reaction product in hot methanol, first add activated carbon to the solution for decolorization, and then recrystallize the solution to obtain 4,4'-biphenol.

[0013] The above-mentioned patent disclosure shows that, in order to solve the color problem of the finished product of 4,4'-biphenol, most of them use hot methanol to dissolve crude 4,4'-biphenol, and add activated carbon for decolorization and purification. Due to the use of methanol, ethanol and other solvents with low flash point and high vapor pressure, on the one hand, the solvent volatilization causes serious losses during the separation and purification process, and on the other hand, the activated carbon after decolorization is difficult to recycle and reuse, and can only be incinerated as hazardous solid waste, and resource recycling cannot be achieved. In addition, through the analysis of the above-mentioned patents, it can be found that the solvent cooling crystallization method is used in the separation and purification. This method is relatively simple to implement, but it cannot guarantee the occurrence of the phenomenon of solvent coating during the crystallization process. Therefore, it is often necessary to repeat recrystallization many times, which causes material loss and energy consumption, or the product after crystallization still needs to be washed and washed to produce a large amount of wastewater. Summary of the invention

[0014] The present application provides a method for separating and purifying 4,4'-biphenol. The present application adopts process technologies including fixed bed, graded loading adsorbent and evaporative crystallization to separate and purify 4,4'-biphenol, so as to achieve low energy consumption, intrinsic safety, low metal content and large-scale production of 4,4'-biphenol.

[0015] The present application provides a method for separating and purifying 4,4'-biphenyl diphenol, which adopts the following technical scheme:

[0016] A method for separating and purifying 4,4'-biphenyldiphenol, the method specifically comprising the following steps:

[0017] The crude product of the debutylation reaction is sent to a filtration system for the first solid-liquid separation;

[0018] Adding a fresh organic solvent or a saturated solvent to the material obtained by the first filtration, fully beating and washing, and sending it to the filtration system for a second solid-liquid separation; the fresh organic solvent is a pure organic solvent, and the saturated solvent is an organic solvent containing 3-10wt% 4,4'-biphenol;

[0019] When the system is initially operated, the material obtained from the first filtration is added to a fresh organic solvent; when the system establishes a cycle, the material obtained from the first filtration is added to a saturated solvent;

[0020] The material obtained by the second filtration is added to hot solvent III, dissolved and mixed, and sent to a fixed bed for adsorption to decolorize and remove metal ions; the fixed bed is filled with a graded adsorbent; the temperature of the hot solvent III is 50-60°C;

[0021] The material after adsorption and decolorization is sent to the evaporation and crystallization unit. After evaporation and crystallization, the material is sent to the filtration system for the third solid-liquid separation. After the separated material is dried, high-purity 4,4'-biphenol is obtained.

[0022] Optionally, the material composition of the debutylation reaction crude product includes but is not limited to benzene-based organic solvents, 4,4'-biphenol, phenol, and semi-debutylated biphenol products.

[0023] Optionally, the benzene-based organic solvent includes but is not limited to m-xylene, o-xylene, p-xylene, and ethylbenzene.

[0024] Optionally, the semi-debutylated biphenol product is an incomplete debutylated intermediate product, which includes but is not limited to a compound of the following chemical formula:

[0025] Formula (I) Formula (II)

[0026] Formula (III) Formula (IV).

[0027] Optionally, the fresh organic solvent and hot solvent III are respectively selected from one or more of dimethyl carbonate, ethyl methyl carbonate, ethyl acetate and ethylene glycol dimethyl ether.

[0028] Optionally, the thermal solvent III is dimethyl carbonate.

[0029] Optionally, the weight ratio of the input amount of the hot solvent III to the material obtained by the second filtration is (1-5):1.

[0030] Optionally, the weight ratio of the input amount of the hot solvent III to the material obtained by the second filtration is 2:1.

[0031] Among them, if the input amount of hot solvent III exceeds the above ratio, it will lead to excessive mother liquor solution product, ultimately resulting in a decrease in the yield of the separated and recovered product, and increase the energy consumption of subsequent separation and purification of hot solvent III.

[0032] Optionally, the dissolving and mixing temperature is 60-70°C.

[0033] Optionally, the graded adsorbent is diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon loaded from top to bottom in a fixed bed.

[0034] Optionally, the volume ratio of the diatomaceous earth, 3A molecular sieve and coconut shell activated carbon is 2:1:3.

[0035] Optionally, the operating temperature of the fixed bed adsorption is 60-80°C.

[0036] Optionally, the operating temperature of the fixed bed adsorption is 70°C.

[0037] Optionally, the evaporation crystallization unit is divided into a normal pressure temperature rising concentration crystallization stage and a vacuum flash evaporation temperature falling crystallization stage.

[0038] Optionally, the normal pressure temperature rising concentration crystallization stage is performed by steam heating the crystallization kettle, and the temperature rising rate is controlled at 5-10°C / h to a final temperature of 100-120°C. When the weight of the evaporated solvent condensate is 20-50% of the weight of the hot solvent III input, the steam heating is stopped and the stage is switched to the vacuum flash cooling crystallization stage.

[0039] Optionally, in the vacuum flash cooling crystallization stage, the vacuum degree of the crystallization kettle is controlled at a rate of 20-30 kPa / h until the final pressure in the crystallization kettle is -90 kPaG, and the evaporation of the solvent is stopped when the weight of the evaporated solvent condensate is controlled to be 50-70% of the weight of the hot solvent III input.

[0040] Optionally, the material obtained by the first filtration, the material obtained by the second filtration and the material obtained by the third solid-liquid separation are all purified by distillation and recycled.

[0041] Optionally, according to liquid chromatography analysis, the purity of the high-purity 4,4'-biphenol is not less than 99.8wt.%; and the separation and purification yield of the 4,4'-biphenol is not less than 80wt.%.

[0042] In summary, the present application includes at least one of the following beneficial technical effects:

[0043] 1. This application provides a purification method for producing electronic grade 4,4'-biphenol, which uses process technologies including fixed bed, graded loading adsorbent and evaporative crystallization to separate and purify 4,4'-biphenol, so as to achieve low energy consumption, intrinsic safety, low metal content and large-scale production of 4,4'-biphenol.

[0044] 2. The method of the present application replaces the traditional process method of using low flash point, high vapor pressure alcohol as a solvent for dissolving crude 4,4'-biphenol, and uses a more environmentally friendly and safe carbonate as a washing and dissolving solvent.

[0045] 3. The fixed and graded loading of different types of adsorbents solves the problems of loss caused by solvent volatilization during separation and purification and the difficulty in recycling activated carbon after decolorization, which can only be incinerated as hazardous solid waste and cannot be recycled.

[0046] 4. Finally, the evaporation crystallization method avoids the risk of multiple recrystallization operations or water washing solvents caused by solvent coating caused by solvent cooling crystallization, resulting in material loss and a large amount of wastewater that is difficult to handle. In this way, the purity of not less than 99.8wt.%, K + Electronic grade 4,4'-biphenyl diphenol with an ion content not exceeding 10 ppm. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The present invention provides a flow chart for separating and purifying 4,4'-biphenol.

[0048] Figure 2 This is a diagram of the device of the evaporation crystallization unit in the process of separating and purifying 4,4'-biphenol provided in this application.

[0049] Figure 3 This is the 4,4'-biphenyl diphenol product separated and purified in this application.

[0050] Figure 4 This is the identification result of the 4,4'-biphenyl diphenol product separated and purified in this application. DETAILED DESCRIPTION

[0051] Before describing the embodiments of the present application in detail, it should be understood that the terms used herein are only for the purpose of describing specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by ordinary technicians in the field to which the terms belong.

[0052] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0053] The endpoints and any values ​​of the ranges disclosed in this application 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.

[0054] In the present application, the terms "include" or "comprising" are open expressions, that is, including the contents specified in the present application, but not excluding other contents.

[0055] The present application provides a method for separating and purifying 4,4'-biphenyl diphenol. The method specifically comprises the following steps:

[0056] The crude product of the debutylation reaction is sent to a filtration system for the first solid-liquid separation;

[0057] The material obtained from the first filtration is added to a saturated solvent, fully slurried and washed, and then sent to a filtration system for a second solid-liquid separation;

[0058] The material obtained by the second filtration is added to hot solvent III, dissolved and mixed, and sent to a fixed bed for adsorption to decolorize and remove metal ions; the fixed bed is filled with a graded adsorbent;

[0059] The material after adsorption and decolorization is sent to the evaporation and crystallization unit. After evaporation and crystallization, the material is sent to the filtration system for the third solid-liquid separation. After the separated material is dried, high-purity 4,4'-biphenol is obtained.

[0060] In a specific embodiment, Figure 1 As shown in the flow chart, a method for separating and purifying 4,4'-biphenyl diphenol specifically comprises the following steps:

[0061] (1) The crude product of the debutylation reaction is sent to the filtration system while hot for the first solid-liquid separation. After centrifugal separation, solid material I and solvent I are obtained.

[0062] (2) Add fresh organic solvent or saturated solvent to solid material I, fully slurry and wash, and send to the filtration system for a second solid-liquid separation. After centrifugal separation, solid material II and solvent II are obtained. The fresh organic solvent is a pure organic solvent, and the saturated solvent is an organic solvent containing 3-10wt% 4,4'-biphenyldiphenol.

[0063] The beating and washing can remove a small amount of solvent I dissolved in the solid material I.

[0064] During the initial operation, since the system has not established a solvent recycling process, fresh organic solvent is added to the solid material I in step (2) when the method is used for the first time; when the system establishes a cycle, a saturated solvent can be used. The saturated solvent is the filtered mother liquor obtained from the third solid-liquid separation, that is, an organic solvent containing 3-10wt% 4,4'-biphenol.

[0065] (3) Add solid material II into hot solvent III, dissolve and mix, and send to fixed bed for adsorption to decolorize and remove metal ions. The temperature of hot solvent III is 50-60°C.

[0066] Among them, the fixed bed is filled with graded adsorbent. The graded adsorbent is diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon filled from top to bottom in the fixed bed. The volume ratio of diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon is 2:1:3. After decolorization and adsorption, the Pt-Co chromaticity value of the material drops from before adsorption to below 20.

[0067] (4) The material after adsorption and decolorization is sent to the evaporation and crystallization unit. After evaporation and crystallization, the material is sent to the filtration system for the third solid-liquid separation. After centrifugal separation, solid material III is obtained.

[0068] Among them, the evaporation crystallization unit is divided into a normal pressure heating concentration crystallization stage and a vacuum flash cooling crystallization stage.

[0069] In the atmospheric pressure heating concentration crystallization stage, the crystallization kettle is heated by steam, and the heating rate is controlled at 5-10°C / h to a final temperature of 100-120°C. When the weight of the evaporated solvent condensate is 20-50% of the weight of the hot solvent III input, the steam heating is stopped and the process is switched to the vacuum flash cooling crystallization stage.

[0070] During the vacuum flash cooling crystallization stage, the vacuum degree of the crystallization kettle is controlled at a rate of 20-30 kPa / h until the final pressure in the crystallization kettle is -90 kPaG. The evaporation of the solvent is stopped when the weight of the evaporated solvent condensate is controlled to be 50-70% of the weight of the hot solvent III input.

[0071] (5) After drying the solid material III, high-purity 4,4'-biphenyl diphenol is obtained. Liquid chromatography analysis shows that the content of 4,4'-biphenyl diphenol in the finished product is not less than 99.8wt.%. Calculation shows that the separation and purification yield of 4,4'-biphenyl diphenol is not less than 80wt.%.

[0072] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0073] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0074] Unless otherwise specified, all concentrations used are mass percentages, and the standard atmospheric pressure is 100 kPa.

[0075] The present application is further described in detail below in conjunction with the embodiments, drawings and test results. Example Example 1

[0076] This embodiment provides a method for separating and purifying 4,4'-biphenyl diphenol.

[0077] like Figure 1 As shown in the process flow chart, the crude 4,4'-biphenol to be separated and purified in this embodiment is a crude product of the debutylation reaction, totaling 12000 kg. After liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 34.3wt.%; o-xylene: 62.4wt.%; phenol: 0.88wt.%; semi-debutylation product: 2.38wt.%; others: 0.04wt.%.

[0078] First, the crude 4,4'-biphenyl diphenol was sent to a horizontal sedimentation spiral screen centrifuge by gravity while hot for solid-liquid separation. After centrifugal separation, solid material I and solvent I were obtained. After weighing, the weight of solid material I was 4235.4 kg. According to liquid chromatography analysis, it contained 5.8 wt.% of o-xylene.

[0079] Then, the solid material I obtained above was added to 10588.5 kg of saturated solvent (dimethyl carbonate in which 3.5 wt% 4,4'-biphenol was dissolved) for recycling, placed in a pulper, pulped and washed, and the temperature in the pulping kettle was maintained at about 65 ° C. After pulping and stirring at a certain stirring speed (there is no requirement for stirring speed) for about 1 hour, it was sent to another horizontal sedimentation spiral screen centrifuge for solid-liquid separation. After centrifugal separation, solid material II and solvent II were obtained. After weighing, the weight of solid material II was 4029.3 kg. After liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 94.8 wt.%; dimethyl carbonate: 4.8 wt.%.

[0080] Next, the solid material II obtained above is sent to a dissolving kettle, and 12000 kg of dimethyl carbonate preheated to 55° C. is added for dissolution and mixing, and the temperature in the dissolving kettle is maintained at not less than 65° C., and the stirring time in the dissolving kettle is maintained at not less than 30 minutes.

[0081] Next, the dissolved and mixed materials in the dissolving kettle are pumped to a fixed bed filled with three adsorbent grades for adsorption to decolorize and remove metal ions. The fixed bed is filled with diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon in a volume ratio of 2:1:3 from top to bottom, and the liquid hourly space velocity is controlled to be no higher than 0.1h -1 After decolorization and adsorption, the Pt-Co chromaticity value of the material decreases from 50 before adsorption to 20, and is sent to the evaporation crystallization unit.

[0082] Among them, the crystallization unit is Figure 2 The crystallization unit includes a crystallization kettle, an evaporative solvent cooler, and a condensate tank.

[0083] The material after decolorization and adsorption is sent to the crystallization kettle, and the temperature is controlled to rise to 100°C at a heating rate of 10°C, and the temperature in the crystallization kettle is maintained at 100°C until the weight of the evaporated solvent condensate is 4800kg (the added hot solvent III is 12000kg, and the weight of the evaporated condensate accounts for 40%), then the crystallization kettle is stopped from heating and switched to the vacuum flash crystallization stage. The vacuum degree in the crystallization kettle is reduced at a rate of 20kPa / h to a pressure of -90kPaG in the crystallization kettle. Due to the decrease in vacuum degree, the temperature in the kettle continues to decrease, and the solvent flashes in the kettle. After condensation, the weight of the evaporated solvent condensate is 8400kg (3600kg of evaporated solvent for flash crystallization, and the weight of the evaporated solvent condensate is 4800kg), and then the crystallization operation is stopped. The solid and liquid materials obtained after cooling were sent to another horizontal sedimentation spiral screen centrifuge by gravity for solid-liquid separation to obtain 3537.8 kg of solid material III, which was dried to obtain 3480.6 kg of finished high-purity 4,4'-biphenol solid.

[0084] like Figure 3 The figure shows the 4,4'-biphenyl diphenol product after separation and purification in this example.

[0085] like Figure 4 The following is the identification result of the 4,4'-biphenyl diphenol product separated and purified in this application. Liquid chromatography analysis shows that the content of 4,4'-biphenyl diphenol in the finished product is 99.83wt.%; metal ion analysis shows that the content of K + The content is 8ppm. After calculation, the separation and purification yield is 84.4wt.%. Example 2

[0086] This embodiment provides a method for separating and purifying 4,4'-biphenyl diphenol.

[0087] like Figure 1 As shown in the process flow chart, the crude 4,4'-biphenol to be separated and purified in this embodiment is a crude product of the debutylation reaction, totaling 12000 kg. After liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 45.3wt.%; p-xylene: 52.4wt.%; phenol: 0.53wt.%; semi-debutylated biphenol product: 1.57wt.%; others: 0.2wt.%.

[0088] First, the crude 4,4'-biphenyl diphenol was sent to a horizontal sedimentation spiral screen centrifuge by gravity while hot for solid-liquid separation. After centrifugal separation, solid material I and solvent I were obtained. After weighing, the weight of solid material I was 5109.8 kg. According to liquid chromatography analysis, it contained 4.8 wt.% of p-xylene.

[0089] Then, the solid material I obtained above was added to 15329.4 kg of saturated solvent (dimethyl carbonate in which 4 wt% 4,4'-biphenol was dissolved) for recycling, placed in a pulper, and pulped and washed, and the temperature in the pulping kettle was maintained at about 65 ° C. After pulping and stirring at a certain stirring speed (there is no requirement for stirring speed) for about 1 hour, it was sent to another horizontal sedimentation spiral screen centrifuge for solid-liquid separation. After centrifugal separation, solid material II and solvent II were obtained. After weighing, the weight of solid material II was 4854.3 kg. After liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 95.3 wt.%; dimethyl carbonate: 4.3 wt.%.

[0090] Next, the solid material II obtained above was sent to a dissolving kettle, and 14500 kg of dimethyl carbonate preheated to 55° C. was added for dissolution and mixing, and the temperature in the dissolving kettle was kept not lower than 65° C., and the stirring time in the dissolving kettle was kept not lower than 30 min.

[0091] Next, the dissolved and mixed materials in the dissolving kettle are pumped to a fixed bed filled with three adsorbent grades for adsorption to decolorize and remove metal ions. The fixed bed is filled with diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon in a volume ratio of 2:1:3 from top to bottom, and the liquid hourly space velocity is controlled to be no higher than 0.1h -1 After decolorization and adsorption, the Pt-Co chromaticity value of the material decreased from 43 to 18 before adsorption and was sent to the evaporation crystallization unit.

[0092] Among them, the crystallization unit is Figure 2 The crystallization unit includes a crystallization kettle, an evaporative solvent cooler, and a condensate tank.

[0093] The material after decolorization and adsorption is sent to the crystallization kettle, and the temperature is controlled to rise to 100°C at a heating rate of 10°C, and the temperature in the crystallization kettle is maintained at 100°C until the weight of the evaporated solvent condensate is 5800kg (the added hot solvent III is 14500kg, and the weight of the evaporated condensate accounts for 40%), then the crystallization kettle is stopped from heating and switched to the vacuum flash crystallization stage. The vacuum degree in the crystallization kettle is reduced at a rate of 20kPa / h to a pressure of -90kPaG in the crystallization kettle. Due to the decrease in vacuum degree, the temperature in the kettle continues to decrease, and the solvent flashes in the kettle. After condensation, the weight of the evaporated solvent condensate is 10000kg (4200kg of the evaporated solvent for flash crystallization, and the weight of the evaporated solvent condensate is 5800kg), and then the crystallization operation is stopped. The solid and liquid materials obtained after cooling were sent to another horizontal sedimentation spiral screen centrifuge by gravity for solid-liquid separation to obtain 4595.3 kg of solid material III. After drying, 4365.5 kg of finished high-purity 4,4'-biphenol solid was obtained.

[0094] Liquid chromatography analysis showed that the content of 4,4'-biphenyldiphenol in the finished product was 99.9wt.%; metal ion analysis showed that the content of K + The content is 5ppm. After calculation, the separation and purification yield is 80.3wt.%. Comparative Example

[0095] This comparative example provides a method for separating and purifying 4,4'-biphenol. The difference between this method and Example 1 is that the step of using a fixed bed graded adsorbent is not adopted, and the rest is the same as Example 1.

[0096] The specific steps of the above method are as follows:

[0097] like Figure 1 As shown in the process flow chart, the crude 4,4'-biphenol to be separated and purified in this comparative example is a crude product of a debutylation reaction, totaling 12,000 kg. According to liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 34.3wt.%; o-xylene: 62.4wt.%; phenol: 0.88wt.%; semi-debutylation product: 2.38wt.%; others: 0.04wt.%.

[0098] First, the crude 4,4'-biphenyl diphenol was sent to a horizontal sedimentation spiral screen centrifuge by gravity while hot for solid-liquid separation. After centrifugal separation, solid material I and solvent I were obtained. After weighing, the weight of solid material I was 4235.4 kg. According to liquid chromatography analysis, it contained 5.8 wt.% of o-xylene.

[0099] Then, the solid material I obtained above was added to 10588.5 kg of saturated solvent (dimethyl carbonate in which 3.5 wt% 4,4'-biphenol was dissolved) for recycling, placed in a pulper, and pulped and washed, and the temperature in the pulping kettle was maintained at about 65 ° C. After pulping and stirring at a certain stirring speed for about 1 hour, it was sent to another horizontal sedimentation spiral screen centrifuge for solid-liquid separation. After centrifugal separation, solid material II and solvent II were obtained. After weighing, the weight of solid material II was 4029.3 kg. After liquid chromatography analysis, its content composition is as follows: 4,4'-biphenol: 94.8 wt.%; dimethyl carbonate: 4.8 wt.%.

[0100] Next, the solid material II obtained above is sent to a dissolving kettle, and 12000 kg of dimethyl carbonate preheated to 55° C. is added for dissolution and mixing, and the temperature in the dissolving kettle is maintained at not less than 65° C., and the stirring time in the dissolving kettle is maintained at not less than 30 minutes.

[0101] Next, the dissolved and mixed materials in the dissolving tank are pumped to the crystallization unit. Figure 2The crystallization unit includes a crystallization kettle, an evaporative solvent cooler, and a condensate tank.

[0102] In the crystallization kettle, the temperature is controlled to rise to 100°C at a heating rate of 10°C, and the temperature in the crystallization kettle is maintained at 100°C until the weight of the evaporated solvent condensate is 4800kg, then the crystallization kettle is stopped from heating and switched to the vacuum flash crystallization stage. The vacuum degree in the crystallization kettle is reduced at a rate of 20kPa / h to a pressure of -90kPaG in the crystallization kettle. Due to the reduction in vacuum degree, the temperature in the kettle continues to decrease, and the solvent flashes in the kettle. After condensation, the weight of the evaporated solvent condensate is 8400kg, and then the crystallization operation is stopped. The solid and liquid materials obtained after cooling are sent to another horizontal sedimentation spiral screen centrifuge by gravity for solid-liquid separation, and solid material III 3537.8kg can be obtained. After drying, 3478.1kg of finished 4,4'-biphenol solid is obtained.

[0103] Liquid chromatography analysis showed that the content of 4,4'-biphenyldiphenol in the finished product was 99.6wt.%; metal ion analysis showed that the content of K + The content is 50ppm, and the Pt-Co chromaticity is 38. After calculation, the separation and purification yield is 84.16wt.%. Since the comparative example is not subjected to adsorption decolorization, the product chromaticity and metal ion content are seriously exceeded.

[0104] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application 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 application.

Claims

1. A method for separating and purifying 4,4'-biphenyldiphenol, characterized in that: The method specifically The following steps are involved: The crude product of the debutylation reaction is sent to a filtration system for the first solid-liquid separation; Adding a fresh organic solvent or a saturated solvent to the material obtained by the first filtration, fully beating and washing, and sending it to the filtration system for a second solid-liquid separation; the fresh organic solvent is a pure organic solvent, and the saturated solvent is an organic solvent containing 3-10wt% of 4,4'-biphenol; When the system is initially operated, the material obtained from the first filtration is added to a fresh organic solvent; when the system establishes a cycle, the material obtained from the first filtration is added to a saturated solvent; The material obtained by the second filtration is added to hot solvent III, dissolved and mixed, and sent to a fixed bed for adsorption to decolorize and remove metal ions; the fixed bed is filled with a graded adsorbent; the temperature of the hot solvent III is 50-60°C; the graded adsorbent is diatomaceous earth, 3A molecular sieve, and coconut shell activated carbon filled from top to bottom in the fixed bed; The material after adsorption and decolorization is sent to an evaporation and crystallization unit, and after evaporation and crystallization, the material is sent to a filtration system for a third solid-liquid separation, and the separated material is dried to obtain high-purity 4,4'-biphenol; The evaporation crystallization unit is divided into a normal pressure heating concentration crystallization stage and a vacuum flash cooling crystallization stage; The normal pressure temperature rising concentration crystallization stage heats the crystallization kettle by steam, and controls the temperature rising speed to 5-10°C / h to a final temperature of 100-120°C. When the weight of the evaporated solvent condensate is 20-50% of the weight of the hot solvent III input, the steam heating is stopped, and the stage of vacuum flash cooling crystallization is switched; In the vacuum flash cooling crystallization stage, the vacuum degree of the crystallization kettle is controlled at a rate of 20-30 kPa / h until the final pressure in the crystallization kettle is -90 kPaG, and the evaporation of the solvent is stopped when the weight of the evaporated solvent condensate is controlled to be 50-70% of the weight of the hot solvent III input; The fresh organic solvent and hot solvent III are dimethyl carbonate.

2. The method according to claim 1, characterized in that The material composition of the debutylation reaction crude product includes, but is not limited to, benzene-based organic solvents, 4,4'-biphenol, phenol, and semi-debutylation products.

3. The method according to claim 2, characterized in that The benzene-based organic solvents include, but are not limited to, m-xylene, o-xylene, p-xylene, and ethylbenzene.

4. The method according to claim 2, characterized in that: The semi-debutylated biphenol product is an incomplete debutylated intermediate product, which includes but is not limited to a compound of the following chemical formula:

5. The method according to claim 1, characterized in that The weight ratio of the input amount of the hot solvent III to the material obtained by the second filtration is (1-5):

1.

6. The method according to claim 1, characterized in that The material obtained by the first filtration, the material obtained by the second filtration and the material obtained by the third solid-liquid separation are all purified by distillation and recycled.

7. The method according to claim 1, characterized in that According to liquid chromatography analysis, the purity of the high-purity 4,4'-biphenol is not less than 99.8wt.%; and the separation and purification yield of the 4,4'-biphenol is not less than 80wt.%.

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