A kind of preparation method of 2-hydroxybiphenyl

Abstract

The invention provides a method for preparing 2-hydroxybiphenyl, belonging to the field of 2-hydroxybiphenyl. The method for preparing 2-hydroxybiphenyl consists of the following steps: preparing an intermediate solution, a primary reaction, a secondary reaction, a tertiary impurity removal, and a post-treatment. The method for preparing 2-hydroxybiphenyl of the invention can improve the purity and yield of the prepared 2-hydroxybiphenyl while continuously producing 2-hydroxybiphenyl on a large scale and over a long period under mild reaction conditions, and reduce production energy consumption, reduce production costs, improve production efficiency, and effectively meet the requirements of large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the field of 2-hydroxybiphenyl, and in particular to a method for preparing 2-hydroxybiphenyl. Background Art

[0002] 2-Hydroxybiphenyl (OPP), also known as o-phenylphenol, is an organic chemical product with a wide range of uses. It is widely used in sterilization and antiseptic, printing and dyeing auxiliaries, printing and dyeing surfactants, and stabilizers and flame retardants for synthesizing new plastics, resins and other polymer materials. 2-Hydroxybiphenyl and its sodium salt have a broad spectrum of sterilization and mildew removal capabilities, and are low-toxic and odorless. They are good preservatives and can be used for mildew prevention and preservation of fruits and vegetables, especially for citrus fruits. They can also be used to treat lemons, pineapples, pears, peaches, tomatoes, cucumbers, etc., which can minimize the decay of fruits and vegetables. At the same time, 2-Hydroxybiphenyl and its sodium salt can also be used as preservatives and bactericides in cosmetics, wood, leather, fiber and paper products. 2-Hydroxybiphenyl and its water-soluble sodium salt can be used as dye carriers for polyester fibers, and can also be used as dye carriers in carrier dyeing of chlorofiber, polyester, etc. Furthermore, by replacing phenol with 2-hydroxybiphenyl, a new type of phenolic resin can be synthesized. The new type of resin has high thermal stability and low water absorption, can be used to prepare paints and other coating products with excellent water and alkali stability, and has wide market applications.

[0003] The existing method of using substituted cyclohexenyl cyclohexanone as raw material and preparing 2-hydroxybiphenyl through catalytic reaction has the problems of high raw material price and high production energy consumption, and is also unable to adapt to large-scale industrial production; at the same time, the existing method of using 2-aminobiphenyl as raw material and preparing 2-hydroxybiphenyl through diazotization, hydrolysis and other processes has the problems of low product purity and yield and high raw material price, and is also unable to adapt to large-scale industrial production. Further, the prior art also discloses a method of using 9-fluorenone as raw material, opening the ring to obtain biphenyl-2-carboxylic acid, and then preparing 2-hydroxybiphenyl through intermittent catalytic reaction, but the intermittent catalytic reaction process needs to be carried out in a high temperature environment for a long time, the production energy consumption is high, the production continuity is poor, the production efficiency is low, the production cost is high, and it is not conducive to large-scale industrial production; and the purity and yield of the obtained 2-hydroxybiphenyl need to be further improved.

[0004] In summary, the existing production methods of 2-hydroxybiphenyl cannot produce 2-hydroxybiphenyl continuously on a large scale and for a long period under mild reaction conditions, while improving the purity and yield of the prepared 2-hydroxybiphenyl, reducing production energy consumption, reducing production costs, and improving production efficiency to meet the requirements of large-scale industrial production. Summary of the invention

[0005] In order to solve the technical problems existing in the prior art, the present invention provides a method for preparing 2-hydroxybiphenyl, which can continuously produce 2-hydroxybiphenyl on a large scale and for a long period under mild reaction conditions, while improving the purity and yield of the prepared 2-hydroxybiphenyl, reducing production energy consumption, reducing production costs, and improving production efficiency, effectively meeting the requirements of large-scale industrial production.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing 2-hydroxybiphenyl comprises the following steps: preparing an intermediate solution, a primary reaction, a secondary reaction, a tertiary impurity removal, and a post-treatment.

[0008] The method for preparing the intermediate solution comprises the following steps: introducing toluene into a reaction kettle with reflux, adding potassium hydroxide into 3-3.5 times the weight of toluene under stirring, stirring and heating to 105-108° C., keeping the temperature and stirring for 20-30 minutes, and then dripping a toluene solution of 9-fluorenone with stirring, and controlling the dripping time of the toluene solution of 9-fluorenone to be 25-35 minutes; after the dripping of the toluene solution of 9-fluorenone is completed, continuing to stir for 40-60 minutes, and naturally cooling to room temperature to obtain a reaction material; mixing the reaction material and deionized water at a weight ratio of 1:0.6-0.7, stirring for 1-1.5 hours, standing and separating to obtain an organic phase and an aqueous phase respectively; extracting the aqueous phase with 0.3-0.4 times the volume of toluene, retaining the toluene layer, combining the toluene layer with the aforementioned organic phase, and adjusting the mass concentration of biphenyl-2-carboxylic acid to 8.5-8.8wt% with toluene to obtain an intermediate solution, i.e., a toluene solution of biphenyl-2-carboxylic acid.

[0009] In the preparation of the intermediate solution, the molar ratio of potassium hydroxide to 9-fluorenone is 1:0.62-0.65;

[0010] In the toluene solution of 9-fluorenone, the mass percentage content of 9-fluorenone is 21-23wt%.

[0011] The method for the primary reaction is to continuously feed the intermediate solution and trifluoromethanesulfonic acid into the primary tubular reactor at the same time, control the reaction temperature in the primary tubular reactor to be 27-30° C., the reaction pressure to be 0.1-0.15 MPa, the feed amount of the intermediate solution to be 80-90 g / min, the material residence time to be 10-12 min, carry out the primary reaction, and obtain the primary reaction liquid.

[0012] In the primary reaction, the molar ratio of trifluoromethanesulfonic acid to biphenyl-2-carboxylic acid in the intermediate solution is 1-1.05:1.

[0013] The secondary reaction method is to continuously feed the primary reaction liquid into the secondary tubular reactor, control the reaction temperature in the secondary tubular reactor to 32-35°C, the reaction pressure to 0.1-0.15MPa, the material residence time to 8-10min, and perform the secondary reaction to obtain the secondary reaction liquid.

[0014] The three-stage impurity removal method is to continuously feed the secondary reaction liquid into the three-stage tubular reactor, control the reaction temperature in the three-stage tubular reactor to 32-35°C, the reaction pressure to 0.1-0.15MPa, and the material residence time to 8-10min to obtain the three-stage impurity removal liquid.

[0015] In the three-stage impurity removal, the three-stage tubular reactor is filled with an impurity removal agent; the filling amount of the impurity removal agent is 2-2.3% of the total weight of the material within the three-stage tubular reactor within a total material residence time of 8-10 minutes.

[0016] The impurity removal treatment agent is prepared by the following steps: ball milling, hydrothermal treatment, and modified granulation;

[0017] The ball milling compounding method comprises the following steps: putting sepiolite, mesoporous activated carbon and ethanol solution into a ball mill, controlling the ball-to-material ratio in the ball mill to be 3-3.6:1, and the ball milling speed to be 110-140 rpm; after ball milling for 5-10 minutes, continuously adding hexadecyltrimethylammonium bromide; after ball milling for 30-40 minutes, continuously adding lauryl alcohol polyoxyethylene ether; after ball milling for 20-30 minutes, obtaining a ball milled product; washing the ball milled product with 1.5-2 times the weight of deionized water, and then putting the ball milled product into 5-6 times the weight of deionized water, stirring for 10-20 minutes, and obtaining a ball milled product dispersion.

[0018] In the ball milling compound, the weight ratio of sepiolite, mesoporous activated carbon, ethanol solution, hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is 8-10:6-7:8-8.5:0.7-0.8:0.5-0.6;

[0019] The specific surface area of ​​sepiolite is 240-270m 2 / g, silicon dioxide content is 56.5-59wt%;

[0020] The specific surface area of ​​mesoporous activated carbon is 900-950m 2 / g, mesopore diameter is 20-26Å, and mesoporosity is 45-50%;

[0021] The volume concentration of the ethanol solution is 65-70%.

[0022] The hydrothermal treatment method comprises placing the ball mill dispersion in a high-pressure reactor, sealing the high-pressure reactor, controlling the heating rate to 1.2-1.6°C / min, stirring and heating to 105-110°C, keeping the temperature and stirring for 40-50 minutes, cooling naturally to room temperature, centrifuging to obtain a solid, and drying the solid at 100-105°C to a constant weight in a vacuum environment of 0.085-0.095MPa to obtain a hydrothermal treated product.

[0023] The modified granulation method comprises the following steps: putting the hydrothermal treated product into a zirconium oxychloride solution of 13-15 times its weight, ultrasonically dispersing the product for 5-10 minutes, stirring the product for 40-60 minutes, then dropping ammonia water into the product to adjust the pH value to 7.2-7.5, standing the product for 60-90 minutes, and centrifuging the product to obtain a solid product; uniformly mixing the solid product with hydroxymethyl cellulose, granulating the solid product, and placing the solid product in a vacuum dryer, drying the product at 100-105° C. to a constant weight in a vacuum environment of 0.085-0.095 MPa, and obtaining an impurity removal treatment agent.

[0024] In the modified granulation, the molar concentration of the zirconium oxychloride solution is 0.1-0.12 mol / L;

[0025] The mass concentration of ammonia water is 8-9wt%;

[0026] The weight ratio of solid matter to hydroxymethyl cellulose is 14-15:1.5-1.8.

[0027] The post-treatment method comprises the following steps: introducing the third-level impurity removal liquid into a crystallization kettle, separating and collecting solids after cooling and crystallization, washing the solids with 2-2.5 times the weight of anhydrous ethanol, and then washing the solids with 3-4 times the weight of deionized water, and then placing the solids in a vacuum dryer, and drying them at 70-75° C. to constant weight in an environment with a vacuum degree of 0.06-0.07 MPa to obtain 2-hydroxybiphenyl.

[0028] In the post-treatment, in order to ensure the continuous flow preparation of 2-hydroxybiphenyl, a plurality of crystallization kettles are arranged in parallel, and the three-stage impurity removal liquid prepared within a certain period of time is post-treated respectively to prepare 2-hydroxybiphenyl.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The method for preparing 2-hydroxybiphenyl of the present invention comprises the following steps: using 9-fluorenone as a starting material, preparing a toluene solution (intermediate solution) of biphenyl 2-carboxylic acid under potassium hydroxide conditions; then continuously feeding the intermediate solution and trifluoromethanesulfonic acid into a primary tubular reactor for primary decarboxylation and hydroxylation, continuously feeding the intermediate solution into a secondary tubular reactor for secondary decarboxylation and hydroxylation, and continuously feeding the intermediate solution into a tertiary tubular reactor filled with an impurity removal treatment agent for tertiary impurity removal to obtain a tertiary impurity removal liquid; then cooling the tertiary impurity removal liquid for crystallization, washing, and drying to obtain 2-hydroxybiphenyl; and at the same time, in the preparation of the impurity removal treatment agent, In the preparation, for impurities in the preparation process of 2-hydroxybiphenyl, cationic hexadecyltrimethylammonium bromide and non-ionic lauryl alcohol polyoxyethylene ether are used to perform ball milling composite treatment on sepiolite and mesoporous activated carbon, so as to improve the adsorption selectivity of impurity components, promote the diffusion and adsorption of impurity components on its surface, avoid the subsequent agglomeration failure of the impurity removal treatment agent in the continuous impurity removal process, and improve the long-term stability of the impurity removal treatment agent; after the ball milling dispersion is obtained by the aforementioned ball milling composite, it is subjected to hydrothermal treatment to further optimize the pore structure of the effective ingredients of the impurity removal treatment agent, and improve the structural stability of the impurity removal treatment agent in the continuous impurity removal process. Qualitative and chemical stability, and further improve its adsorption performance for impurity components; after the hydrothermal treatment is obtained by the above-mentioned hydrothermal treatment, it is modified and granulated, and zirconium oxychloride and ammonia water are used to modify the hydrothermal treatment, so as to further improve the strength of the impurity removal agent and its structural stability in the continuous impurity removal process, and improve the adaptability of the impurity removal agent to long-term continuous impurity removal, so that it can maintain ideal adsorption performance for a long time, avoid the reduction of adsorption performance caused by possible structural damage in the long-term continuous impurity removal process, and finally combine with hydroxymethyl cellulose to obtain the impurity removal agent; the above-mentioned technical means cooperate with each other , synergistic effect, can under mild reaction conditions, large-scale, long-term continuous production of 2-hydroxybiphenyl, while improving the purity and yield of the prepared 2-hydroxybiphenyl, and reducing production energy consumption, reducing production costs, improving production efficiency, and effectively meeting the requirements of large-scale industrial production; at the same time, the impurity removal treatment agent used can effectively adapt to long-term continuous impurity removal conditions, can effectively remove impurities and decolorize the secondary reaction liquid, has good adaptability to long-term continuous impurity removal, and can maintain ideal structural stability and adsorption performance during the continuous impurity removal process, avoiding possible structural damage during the long-term continuous impurity removal process. Reduced adsorption performance caused by.

[0031] (2) The method for preparing 2-hydroxybiphenyl of the present invention has a HPLC purity of 99.6-99.8 wt % and a molar yield (based on 9-fluorenone) of 93.0-93.2 %.

[0032] (3) In the preparation method of 2-hydroxybiphenyl of the present invention, after the impurity removal agent is continuously used for 300 hours, the HPLC purity of the prepared 2-hydroxybiphenyl can still reach 99.5wt%, and the molar yield (calculated as 9-fluorenone) can still reach 92.8%.

[0033] (4) The method for preparing 2-hydroxybiphenyl of the present invention has a simple process flow and is easy to control. It can produce 2-hydroxybiphenyl continuously on a large scale over a long period of time under mild reaction conditions. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0035] Example 1

[0036] A method for preparing 2-hydroxybiphenyl comprises the following steps:

[0037] 1. Preparation of intermediate solution

[0038] Toluene is introduced into a reaction kettle with reflux, and potassium hydroxide is added to 3 times the weight of toluene under stirring, and the temperature is raised to 105° C. with stirring, and after keeping the temperature and stirring for 20 minutes, the toluene solution of 9-fluorenone is added dropwise with stirring, and the dropping time of the toluene solution of 9-fluorenone is controlled to be 25 minutes; after the toluene solution of 9-fluorenone is added dropwise, stirring is continued for 40 minutes, and then naturally cooled to room temperature to obtain a reaction material; the reaction material and deionized water are mixed at a weight ratio of 1:0.6, stirred for 1 hour, and allowed to stand for stratification to obtain an organic phase and an aqueous phase respectively; after the aqueous phase is extracted with 0.3 times the volume of toluene, the toluene layer is retained, and the toluene layer is combined with the aforementioned organic phase, and the mass concentration of biphenyl-2-carboxylic acid is adjusted to 8.5wt% with toluene to obtain an intermediate solution, i.e., a toluene solution of biphenyl-2-carboxylic acid.

[0039] Wherein, the molar ratio of potassium hydroxide to 9-fluorenone is 1:0.62.

[0040] In the toluene solution of 9-fluorenone, the mass percentage content of 9-fluorenone is 21wt%.

[0041] 2. First-order reaction

[0042] At the same time, the intermediate solution and trifluoromethanesulfonic acid are continuously fed into the primary tubular reactor, the reaction temperature in the primary tubular reactor is controlled to be 27° C., the reaction pressure is controlled to be 0.1 MPa, the feed amount of the intermediate solution is 80 g / min, the material residence time is 10 min, and a primary reaction is carried out to obtain a primary reaction liquid.

[0043] The molar ratio of trifluoromethanesulfonic acid to biphenyl-2-carboxylic acid in the intermediate solution is 1.02:1.

[0044] 3. Secondary reaction

[0045] The primary reaction liquid was continuously fed into the secondary tubular reactor, the reaction temperature in the secondary tubular reactor was controlled to be 32° C., the reaction pressure was controlled to be 0.1 MPa, the material residence time was controlled to be 8 min, and the secondary reaction was carried out to obtain the secondary reaction liquid.

[0046] 4. Three-level impurity removal

[0047] The secondary reaction liquid was continuously fed into the tertiary tubular reactor, the reaction temperature in the tertiary tubular reactor was controlled to be 32° C., the reaction pressure was controlled to be 0.1 MPa, and the material residence time was controlled to be 8 min, to obtain a tertiary impurity removal liquid.

[0048] The three-stage tubular reactor is filled with an impurity removal agent; the amount of the impurity removal agent filled is 2% of the total weight of the material within the total material residence time (8 minutes) in the three-stage tubular reactor.

[0049] The impurity removal treatment agent is prepared by the following steps:

[0050] 1) Ball milling

[0051] Put sepiolite, mesoporous activated carbon and ethanol solution into a ball mill, control the ball-to-material ratio in the ball mill to be 3:1, and the ball mill speed to be 110 rpm. After ball milling for 5 minutes, continue to add hexadecyltrimethylammonium bromide. After ball milling for 30 minutes, continue to add lauryl alcohol polyoxyethylene ether. After ball milling for 20 minutes, a ball-milled product is obtained. After washing the ball-milled product with 1.5 times the weight of deionized water, the ball-milled product is put into 5 times the weight of deionized water and stirred for 10 minutes to obtain a ball-milled product dispersion.

[0052] Among them, the weight ratio of sepiolite, mesoporous activated carbon, ethanol solution, hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is 8:6:8:0.7:0.5.

[0053] The specific surface area of ​​sepiolite is 260m 2 / g, and the silicon dioxide content is 58.3wt%.

[0054] The specific surface area of ​​mesoporous activated carbon is 930m 2 / g, the mesopore diameter is 25Å and the mesoporosity is 47%.

[0055] The volume concentration of the ethanol solution is 65%.

[0056] 2) Hydrothermal treatment

[0057] The ball mill dispersion was placed in a high-pressure reactor. After the high-pressure reactor was sealed, the heating rate was controlled to be 1.2°C / min, the temperature was raised to 105°C with stirring, and the mixture was kept stirring for 40 minutes. After naturally cooling to room temperature, the solid was obtained by centrifugation. The solid was dried at 100°C to constant weight in a vacuum environment of 0.085 MPa to obtain a hydrothermal treated product.

[0058] 3) Modified granulation

[0059] The hydrothermal treated product was put into a zirconium oxychloride solution with a weight of 13 times, and after ultrasonic dispersion for 5 minutes, it was stirred for 40 minutes, and then ammonia water was added dropwise with stirring to adjust the pH to 7.2. After standing for 60 minutes, solid matter was obtained by centrifugation. The solid matter was evenly mixed with hydroxymethyl cellulose, granulated, placed in a vacuum dryer, and dried to constant weight at 100°C in a vacuum environment of 0.085MPa to obtain an impurity removal treatment agent.

[0060] Wherein, the molar concentration of the zirconium oxychloride solution is 0.1 mol / L.

[0061] The mass concentration of ammonia water is 8wt%.

[0062] The weight ratio of solid matter to hydroxymethyl cellulose is 14:1.5.

[0063] 5. Post-processing

[0064] The tertiary impurity removal liquid is introduced into a crystallization kettle, and after cooling and crystallization, the solid is separated and collected, and the solid is washed with 2 times the weight of anhydrous ethanol, and then with 3 times the weight of deionized water, and then placed in a vacuum dryer, and dried at 70° C. to constant weight in a vacuum environment of 0.06 MPa to obtain 2-hydroxybiphenyl.

[0065] In the preparation method of 2-hydroxybiphenyl of this embodiment, the intermediate solution is fed into the primary tubular reactor for 60 minutes, and 359.87 g of 2-hydroxybiphenyl is prepared, the HPLC purity is 99.8 wt %, and the molar yield (calculated as 9-fluorenone) is 93.2%.

[0066] Example 2

[0067] A method for preparing 2-hydroxybiphenyl comprises the following steps:

[0068] 1. Preparation of intermediate solution

[0069] Toluene is introduced into a reaction kettle with reflux, and potassium hydroxide is added to 3.2 times the weight of toluene under stirring, and the temperature is raised to 106° C. with stirring, and after keeping the temperature and stirring for 25 minutes, the toluene solution of 9-fluorenone is added dropwise with stirring, and the dropping time of the toluene solution of 9-fluorenone is controlled to be 30 minutes; after the toluene solution of 9-fluorenone is added dropwise, stirring is continued for 50 minutes, and then naturally cooled to room temperature to obtain a reaction material; the reaction material and deionized water are mixed at a weight ratio of 1:0.65, stirred for 1.2 hours, and allowed to stand for stratification to obtain an organic phase and an aqueous phase, respectively; after the aqueous phase is extracted with 0.35 times the volume of toluene, the toluene layer is retained, and the toluene layer is combined with the aforementioned organic phase, and the mass concentration of biphenyl-2-carboxylic acid is adjusted to 8.6wt% with toluene to obtain an intermediate solution, i.e., a toluene solution of biphenyl-2-carboxylic acid.

[0070] Wherein, the molar ratio of potassium hydroxide to 9-fluorenone is 1:0.63.

[0071] In the toluene solution of 9-fluorenone, the mass percentage content of 9-fluorenone is 22wt%.

[0072] 2. First-order reaction

[0073] At the same time, the intermediate solution and trifluoromethanesulfonic acid are continuously fed into the primary tubular reactor, the reaction temperature in the primary tubular reactor is controlled to be 28° C., the reaction pressure is controlled to be 0.12 MPa, the feed amount of the intermediate solution is 85 g / min, the material residence time is 11 min, and a primary reaction is carried out to obtain a primary reaction liquid.

[0074] The molar ratio of trifluoromethanesulfonic acid to biphenyl-2-carboxylic acid in the intermediate solution is 1.03:1.

[0075] 3. Secondary reaction

[0076] The primary reaction liquid was continuously fed into the secondary tubular reactor, the reaction temperature in the secondary tubular reactor was controlled to be 33° C., the reaction pressure was controlled to be 0.12 MPa, the material residence time was controlled to be 9 min, and the secondary reaction was carried out to obtain the secondary reaction liquid.

[0077] 4. Three-level impurity removal

[0078] The secondary reaction liquid was continuously fed into the tertiary tubular reactor, the reaction temperature in the tertiary tubular reactor was controlled to be 33° C., the reaction pressure was controlled to be 0.12 MPa, and the material residence time was controlled to be 9 min, to obtain a tertiary impurity removal liquid.

[0079] The three-stage tubular reactor is filled with an impurity removal agent; the amount of the impurity removal agent filled is 2.2% of the total weight of the material within the total material residence time (9 minutes) in the three-stage tubular reactor.

[0080] The impurity removal treatment agent is prepared by the following steps:

[0081] 1) Ball milling

[0082] Put sepiolite, mesoporous activated carbon and ethanol solution into a ball mill, control the ball-to-material ratio in the ball mill to be 3.5:1, and the ball mill speed to be 130 rpm. After ball milling for 8 minutes, continue to add hexadecyltrimethylammonium bromide. After ball milling for 35 minutes, continue to add lauryl alcohol polyoxyethylene ether. After ball milling for 25 minutes, obtain a ball-milled product. After washing the ball-milled product with 1.8 times the weight of deionized water, put the ball-milled product into 5.5 times the weight of deionized water, stir for 15 minutes, and obtain a ball-milled product dispersion.

[0083] Among them, the weight ratio of sepiolite, mesoporous activated carbon, ethanol solution, hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is 9:6.5:8.3:0.75:0.55.

[0084] The specific surface area of ​​sepiolite is 260m 2 / g, and the silicon dioxide content is 58.3wt%.

[0085] The specific surface area of ​​mesoporous activated carbon is 930m 2 / g, the mesopore diameter is 25Å and the mesoporosity is 47%.

[0086] The volume concentration of the ethanol solution is 67.5%.

[0087] 2) Hydrothermal treatment

[0088] The ball mill dispersion was placed in a high-pressure reactor. After the high-pressure reactor was sealed, the heating rate was controlled to be 1.4°C / min, the temperature was raised to 108°C with stirring, and the mixture was kept stirring for 45 minutes. After naturally cooling to room temperature, the solid was obtained by centrifugation. The solid was dried at 102°C to constant weight in a vacuum environment of 0.09 MPa to obtain a hydrothermal treated product.

[0089] 3) Modified granulation

[0090] The hydrothermally treated product was put into a zirconium oxychloride solution with a weight of 14 times, and after ultrasonic dispersion for 8 minutes, it was stirred for 50 minutes, and then ammonia water was added dropwise with stirring to adjust the pH value to 7.3. After standing for 80 minutes, solid matter was obtained by centrifugation. The solid matter was evenly mixed with hydroxymethyl cellulose, granulated, placed in a vacuum dryer, and dried at 102°C to constant weight in a vacuum environment of 0.09 MPa to obtain an impurity removal treatment agent.

[0091] Wherein, the molar concentration of the zirconium oxychloride solution is 0.11 mol / L.

[0092] The mass concentration of ammonia water is 8.5wt%.

[0093] The weight ratio of solid matter to hydroxymethyl cellulose is 14.5:1.6.

[0094] 5. Post-processing

[0095] The tertiary impurity removal liquid is introduced into a crystallization kettle, and after cooling and crystallization, the solid is separated and collected, and the solid is washed with 2.3 times the weight of anhydrous ethanol, and then with 3.5 times the weight of deionized water, and then placed in a vacuum dryer, and dried at 72° C. to constant weight in a vacuum environment of 0.065 MPa to obtain 2-hydroxybiphenyl.

[0096] In the preparation method of 2-hydroxybiphenyl of this embodiment, the intermediate solution is fed into the primary tubular reactor for 60 minutes, and 386.42 g of 2-hydroxybiphenyl is prepared, the HPLC purity is 99.7 wt %, and the molar yield (calculated as 9-fluorenone) is 93.0%.

[0097] Example 3

[0098] A method for preparing 2-hydroxybiphenyl comprises the following steps:

[0099] 1. Preparation of intermediate solution

[0100] Toluene is introduced into a reaction kettle with reflux, and potassium hydroxide is added to 3.5 times the weight of toluene under stirring, and the temperature is raised to 108° C. with stirring, and after keeping the temperature and stirring for 30 minutes, the toluene solution of 9-fluorenone is added dropwise with stirring, and the dropping time of the toluene solution of 9-fluorenone is controlled to be 35 minutes; after the toluene solution of 9-fluorenone is added dropwise, stirring is continued for 60 minutes, and then naturally cooled to room temperature to obtain a reaction material; the reaction material and deionized water are mixed at a weight ratio of 1:0.7, stirred for 1.5 hours, and allowed to stand for stratification to obtain an organic phase and an aqueous phase respectively; after the aqueous phase is extracted with 0.4 times the volume of toluene, the toluene layer is retained, and the toluene layer is combined with the aforementioned organic phase, and the mass concentration of biphenyl-2-carboxylic acid is adjusted to 8.8wt% with toluene to obtain an intermediate solution, i.e., a toluene solution of biphenyl-2-carboxylic acid.

[0101] Wherein, the molar ratio of potassium hydroxide to 9-fluorenone is 1:0.65.

[0102] In the toluene solution of 9-fluorenone, the mass percentage content of 9-fluorenone is 23wt%.

[0103] 2. First-order reaction

[0104] At the same time, the intermediate solution and trifluoromethanesulfonic acid are continuously fed into the primary tubular reactor, the reaction temperature in the primary tubular reactor is controlled to be 30° C., the reaction pressure is controlled to be 0.15 MPa, the feed amount of the intermediate solution is 90 g / min, the material residence time is 12 min, and a primary reaction is carried out to obtain a primary reaction liquid.

[0105] The molar ratio of trifluoromethanesulfonic acid to biphenyl-2-carboxylic acid in the intermediate solution is 1.05:1.

[0106] 3. Secondary reaction

[0107] The primary reaction liquid was continuously fed into the secondary tubular reactor, the reaction temperature in the secondary tubular reactor was controlled to be 35° C., the reaction pressure was controlled to be 0.15 MPa, the material residence time was controlled to be 10 min, and the secondary reaction was carried out to obtain the secondary reaction liquid.

[0108] 4. Three-level impurity removal

[0109] The secondary reaction liquid was continuously fed into the tertiary tubular reactor, the reaction temperature in the tertiary tubular reactor was controlled to be 35° C., the reaction pressure was controlled to be 0.15 MPa, and the material residence time was controlled to be 10 min, to obtain a tertiary impurity removal liquid.

[0110] The three-stage tubular reactor is filled with an impurity removal agent; the amount of the impurity removal agent filled is 2.3% of the total weight of the material within the total material residence time (10 minutes) in the three-stage tubular reactor.

[0111] The impurity removal treatment agent is prepared by the following steps:

[0112] 1) Ball milling

[0113] Put sepiolite, mesoporous activated carbon and ethanol solution into a ball mill, control the ball-to-material ratio in the ball mill to be 3.6:1, and the ball mill speed to be 140 rpm. After ball milling for 10 minutes, continue to add hexadecyltrimethylammonium bromide. After ball milling for 40 minutes, continue to add lauryl alcohol polyoxyethylene ether. After ball milling for 30 minutes, obtain a ball-milled product. After washing the ball-milled product with 2 times the weight of deionized water, put the ball-milled product into 6 times the weight of deionized water and stir for 20 minutes to obtain a ball-milled product dispersion.

[0114] Among them, the weight ratio of sepiolite, mesoporous activated carbon, ethanol solution, hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is 10:7:8.5:0.8:0.6.

[0115] The specific surface area of ​​sepiolite is 260m 2 / g, and the silicon dioxide content is 58.3wt%.

[0116] The specific surface area of ​​mesoporous activated carbon is 930m2 / g, the mesopore diameter is 25Å and the mesoporosity is 47%.

[0117] The volume concentration of the ethanol solution is 70%.

[0118] 2) Hydrothermal treatment

[0119] The ball mill dispersion was placed in a high-pressure reactor. After the high-pressure reactor was sealed, the heating rate was controlled to be 1.6°C / min, the temperature was raised to 110°C with stirring, and the mixture was kept stirring for 50 minutes. After naturally cooling to room temperature, the solid was obtained by centrifugation. The solid was dried at 105°C to constant weight in a vacuum environment of 0.095 MPa to obtain a hydrothermal treated product.

[0120] 3) Modified granulation

[0121] The hydrothermal treated product was put into a 15-times-weight zirconium oxychloride solution, ultrasonically dispersed for 10 minutes, stirred for 60 minutes, and then ammonia water was added dropwise with stirring to adjust the pH value to 7.5. After standing for 90 minutes, solid matter was obtained by centrifugation. The solid matter was evenly mixed with hydroxymethyl cellulose, granulated, placed in a vacuum dryer, dried at 105°C to constant weight in a vacuum environment of 0.095 MPa, and an impurity removal treatment agent was obtained.

[0122] Wherein, the molar concentration of the zirconium oxychloride solution is 0.12 mol / L.

[0123] The mass concentration of ammonia water is 9wt%.

[0124] The weight ratio of solid matter to hydroxymethyl cellulose is 15:1.8.

[0125] 5. Post-processing

[0126] The tertiary impurity removal liquid is introduced into a crystallization kettle, and after cooling and crystallization, the solid is separated and collected, and the solid is washed with 2.5 times the weight of anhydrous ethanol, and then washed with 4 times the weight of deionized water, and then placed in a vacuum dryer, and dried at 75° C. to constant weight in a vacuum environment of 0.07 MPa to obtain 2-hydroxybiphenyl.

[0127] In the preparation method of 2-hydroxybiphenyl of this embodiment, the intermediate solution is fed into the primary tubular reactor for 60 minutes, and 419.54 g of 2-hydroxybiphenyl is prepared, with a HPLC purity of 99.6 wt % and a molar yield (based on 9-fluorenone) of 93.1%.

[0128] Comparative Example 1

[0129] The technical solution of Example 2 is adopted, but the differences are: 1) the secondary reaction step is omitted; 2) in the preparation of the impurity removal treatment agent, the hydrothermal treatment step is omitted.

[0130] According to the preparation method of 2-hydroxybiphenyl in Comparative Example 1, the intermediate solution was fed into the primary tubular reactor for 60 minutes, and 392.29 g of 2-hydroxybiphenyl was obtained, with a HPLC purity of 90.5 wt %, and a molar yield (based on 9-fluorenone) of 85.7%.

[0131] It can be seen from Comparative Example 1 that after omitting the secondary reaction, the decarboxylation hydroxylation reaction of the intermediate solution with trifluoromethanesulfonic acid is not complete, which increases the difficulty of subsequent product impurity removal and purification, resulting in a decrease in product yield; at the same time, after omitting the hydrothermal treatment in the preparation of the impurity removal treatment agent, the pore structure of the effective ingredient of the impurity removal treatment agent cannot be further optimized, the structural stability and chemical stability of the impurity removal treatment agent in the continuous impurity removal process are reduced, and its adsorption performance for impurity components is reduced; specifically, the purity of the continuously prepared 2-hydroxybiphenyl is reduced to a certain extent, and the yield is significantly reduced.

[0132] Comparative Example 2

[0133] The technical scheme of Example 2 is adopted, but the differences are as follows: 1) in the preparation of the impurity removal agent, the ball milling compounding step is omitted, and mesoporous activated carbon is used instead of the ball milled product to be put into deionized water for subsequent hydrothermal treatment; 2) in the preparation of the impurity removal agent, in the modified granulation step, the hydrothermally treated product is directly mixed with hydroxymethyl cellulose for granulation, and dried to obtain the impurity removal agent.

[0134] In the preparation method of 2-hydroxybiphenyl in Comparative Example 2, the intermediate solution was fed into the primary tubular reactor for 60 minutes, and 436.88 g of 2-hydroxybiphenyl was obtained, with a HPLC purity of 87.9 wt %, and a molar yield (based on 9-fluorenone) of 92.7%.

[0135] It can be seen from Comparative Example 2 that in the preparation of the impurity removal agent, the combination of sepiolite and mesoporous activated carbon is omitted, and the ball milling composite treatment of hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is omitted, the adsorption selectivity of the impurity components in the reaction solution is reduced, and the diffusion and adsorption of the impurity components on its surface cannot be effectively promoted, and the subsequent impurity removal agent may have the problem of agglomeration failure in the continuous impurity removal process; at the same time, in the modified granulation step, the modification treatment of the hydrothermal treatment product by combining zirconium oxychloride and ammonia water is omitted, and the stability of the impurity removal agent in the continuous impurity removal process cannot be further improved; specifically, the purity of the continuously prepared 2-hydroxybiphenyl is significantly reduced.

[0136] The preparation method of 2-hydroxybiphenyl in Example 2 was adopted, and the impurity removal treatment agents in Example 2, Comparative Example 1, and Comparative Example 2 were respectively used to carry out a long-term impurity removal stability test. The preparation method of Example 2 was adopted to prepare 2-hydroxybiphenyl, and the impurity removal treatment agents in Example 2, Comparative Example 1, and Comparative Example 2 were respectively continuously worked for 300 hours, and the liquid chromatography purity of the prepared 2-hydroxybiphenyl was detected, and the molar yield was calculated based on the raw material 9-fluorenone. The specific results are shown in the following table:

[0137]

[0138] It can be seen that in the preparation method of 2-hydroxybiphenyl of the present invention, 9-fluorenone is used as a starting material to prepare a toluene solution (intermediate solution) of biphenyl 2-carboxylic acid under potassium hydroxide conditions; then the intermediate solution and trifluoromethanesulfonic acid are continuously fed into a first-stage tubular reactor to carry out a first-stage decarboxylation hydroxylation reaction, and then the intermediate solution is continuously fed into a second-stage tubular reactor to carry out a second-stage decarboxylation hydroxylation reaction, and then the intermediate solution is continuously fed into a third-stage tubular reactor filled with an impurity removal treatment agent to carry out a third-stage impurity removal treatment to obtain a third-stage impurity removal liquid; then the third-stage impurity removal liquid is cooled, crystallized, washed, and dried to obtain 2-hydroxybiphenyl; at the same time, in the impurity removal treatment agent In the preparation of the invention, for impurities in the preparation process of 2-hydroxybiphenyl, cationic hexadecyltrimethylammonium bromide and non-ionic lauryl alcohol polyoxyethylene ether are used to combine sepiolite and mesoporous activated carbon for ball milling composite treatment, so as to improve the adsorption selectivity of impurity components, promote the diffusion and adsorption of impurity components on its surface, avoid the subsequent agglomeration failure of the impurity removal treatment agent in the continuous impurity removal process, and improve the long-term stability of the impurity removal treatment agent; after the ball milling dispersion is obtained by the above-mentioned ball milling composite, it is subjected to hydrothermal treatment to further optimize the pore structure of the effective components of the impurity removal treatment agent, and improve the structure of the impurity removal treatment agent in the continuous impurity removal process. Stability and chemical stability, and further improve its adsorption performance for impurity components; after the hydrothermal treatment is obtained by the above-mentioned hydrothermal treatment, it is modified and granulated, and zirconium oxychloride and ammonia water are used to modify the hydrothermal treatment, so as to further improve the strength of the impurity removal treatment agent and its structural stability in the continuous impurity removal process, and improve the adaptability of the impurity removal treatment agent to long-term continuous impurity removal, so that it can maintain ideal adsorption performance for a long time, avoid the reduction of adsorption performance caused by possible structural damage in the long-term continuous impurity removal process, and finally combine with hydroxymethyl cellulose to obtain the impurity removal treatment agent; the above-mentioned technical means cooperate with each other , synergistic effect, can under mild reaction conditions, large-scale, long-term continuous production of 2-hydroxybiphenyl, while improving the purity and yield of the prepared 2-hydroxybiphenyl, and reducing production energy consumption, reducing production costs, improving production efficiency, and effectively meeting the requirements of large-scale industrial production; at the same time, the impurity removal treatment agent used can effectively adapt to long-term continuous impurity removal conditions, can effectively remove impurities and decolorize the secondary reaction liquid, has good adaptability to long-term continuous impurity removal, and can maintain ideal structural stability and adsorption performance during the continuous impurity removal process, avoiding possible structural damage during the long-term continuous impurity removal process. Reduced adsorption performance caused by.

[0139] After the impurity removal agent of Comparative Example 1 worked continuously for 300 hours, the purity and yield of the obtained 2-hydroxybiphenyl were reduced to a certain extent compared with the impurity removal agent of Example 2. Analysis showed that after the hydrothermal treatment was omitted in the preparation of the impurity removal agent, the pore structure of the effective ingredient of the impurity removal agent could not be further optimized, and the structural stability and chemical stability of the impurity removal agent were reduced during the continuous impurity removal process, which ultimately led to a decrease in the long-term adsorption performance of the impurity removal agent.

[0140] After the impurity removal agent of Comparative Example 2 worked continuously for 300 hours, the purity and yield of the prepared 2-hydroxybiphenyl were significantly reduced compared with the impurity removal agent of Example 2. After analysis, the impurity removal agent was prone to agglomeration failure during long-term continuous impurity removal after the remaining sepiolite was combined with mesoporous activated carbon and the ball milling composite treatment of hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether was omitted; at the same time, in the modified granulation step, the modification treatment of the hydrothermal treatment product by zirconium oxychloride and ammonia water was omitted, and the strength of the impurity removal agent and its structural stability in the continuous impurity removal process could not be effectively improved. The adaptability of the impurity removal agent to long-term continuous impurity removal was reduced, and the ideal adsorption performance could not be maintained for a long time.

[0141] Unless otherwise specified, all percentages used in the present invention are by mass.

[0142] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing 2-hydroxybiphenyl, characterized in that: The method comprises the following steps: preparation of intermediate solution, primary reaction, secondary reaction, tertiary impurity removal, and post-treatment; The method for preparing the intermediate solution is to react 9-fluorenone and potassium hydroxide in toluene to prepare an intermediate solution with a mass concentration of biphenyl-2-carboxylic acid of 8.5-8.8wt%; The method of the primary reaction is to continuously feed the intermediate solution and trifluoromethanesulfonic acid into the primary tubular reactor at the same time, control the reaction temperature in the primary tubular reactor to 27-30° C., perform the primary reaction, and obtain the primary reaction liquid; The secondary reaction method is to continuously feed the primary reaction liquid into the secondary tubular reactor, control the reaction temperature in the secondary tubular reactor to be 32-35° C., perform the secondary reaction, and obtain the secondary reaction liquid; The three-stage impurity removal method is to continuously feed the secondary reaction liquid into the three-stage tubular reactor, control the reaction temperature in the three-stage tubular reactor to be 32-35° C., and obtain the three-stage impurity removal liquid; The three-stage tubular reactor is filled with an impurity removal agent, which is prepared by the following steps: ball milling, hydrothermal treatment, and modified granulation; The ball milling compounding method comprises the following steps: after the sepiolite, mesoporous activated carbon and ethanol solution are ball milled uniformly, hexadecyl trimethyl ammonium bromide is added, the ball milling treatment is performed for 30-40 minutes, and then lauryl alcohol polyoxyethylene ether is added, the ball milling treatment is performed for 20-30 minutes to obtain a ball milled product; after the ball milled product is washed with deionized water, the product is added into deionized water for uniform dispersion to obtain a ball milled product dispersion; In the ball milling compound, the weight ratio of sepiolite, mesoporous activated carbon, ethanol solution, hexadecyltrimethylammonium bromide and lauryl alcohol polyoxyethylene ether is 8-10:6-7:8-8.5:0.7-0.8:0.5-0.6; In the ball milling compound, the specific surface area of ​​sepiolite is 240-270m 2 / g, silicon dioxide content is 56.5-59wt%; The specific surface area of ​​mesoporous activated carbon is 900-950m 2 / g, mesopore diameter is 20-26Å, and mesoporosity is 45-50%; In the ball milling compound, the volume concentration of the ethanol solution is 65-70%; The hydrothermal treatment method comprises placing the ball mill dispersion in a high pressure reactor, sealing the high pressure reactor, stirring and heating to 105-110° C., keeping the temperature and stirring for 40-50 minutes, cooling naturally to room temperature, separating and obtaining a solid, and drying to obtain a hydrothermal treatment product; During the hydrothermal treatment, the heating rate is controlled to be 1.2-1.6°C / min; The modified granulation method comprises: putting the hydrothermal treated product into a zirconium oxychloride solution, stirring after uniform dispersion, adjusting the pH to 7.2-7.5 with ammonia water, standing, and separating to obtain a solid; mixing the solid with hydroxymethyl cellulose to form granules, and drying to obtain an impurity removal treatment agent; In the modified granulation, the weight ratio of the hydrothermal treatment product to the zirconium oxychloride solution is 1:13-15; The molar concentration of the zirconium oxychloride solution is 0.1-0.12 mol / L; The mass concentration of ammonia water is 8-9wt%; In the modified granulation, the weight ratio of solid matter to hydroxymethyl cellulose is 14-15:1.5-1.8; The post-treatment method is as follows: after cooling and crystallizing the tertiary impurity removal liquid, the solid matter is separated and collected, and the solid matter is washed with anhydrous ethanol and deionized water in sequence and then dried to obtain 2-hydroxybiphenyl.

2. The method for preparing 2-hydroxybiphenyl according to claim 1, characterized in that: The molar ratio of potassium hydroxide to 9-fluorenone is 1:0.62-0.

65.

3. The method for preparing 2-hydroxybiphenyl according to claim 1, characterized in that: In the first-stage reaction, the reaction pressure is 0.1-0.15 MPa, and the material residence time is 10-12 min; In the secondary reaction, the reaction pressure is 0.1-0.15 MPa, and the material residence time is 8-10 min; In the three-stage impurity removal, the reaction pressure is 0.1-0.15 MPa, and the material residence time is 8-10 min.

4. The method for preparing 2-hydroxybiphenyl according to claim 1, characterized in that: In the primary reaction, the feed rate of the intermediate solution is 80-90 g / min; The molar ratio of trifluoromethanesulfonic acid to biphenyl-2-carboxylic acid in the intermediate solution is 1-1.05:1; In the three-stage impurity removal, the loading amount of the impurity removal agent is 2-2.3% of the total weight of the materials within the three-stage tubular reactor within a total material residence time of 8-10 minutes.

5. The method for preparing 2-hydroxybiphenyl according to claim 1, characterized in that: The method for preparing the intermediate solution comprises the following steps: adding potassium hydroxide into toluene, stirring and heating to 105-108° C., keeping the temperature and stirring, and then dripping a toluene solution of 9-fluorenone; after the toluene solution of 9-fluorenone is dripped, stirring is continued, and the mixture is naturally cooled to room temperature to obtain a reaction mass; the reaction mass and deionized water are mixed, stirred, and allowed to stand for stratification to obtain an organic phase and an aqueous phase respectively; after the aqueous phase is extracted with toluene, the toluene layer is retained, and the toluene layer is combined with the organic phase, and the mass concentration of biphenyl-2-carboxylic acid is adjusted to 8.5-8.8wt% with toluene to obtain an intermediate solution.

6. The method for preparing 2-hydroxybiphenyl according to claim 5, characterized in that: In the preparation of the intermediate solution, the toluene solution of 9-fluorenone is added dropwise for 25-35 minutes; In the toluene solution of 9-fluorenone, the mass percentage content of 9-fluorenone is 21-23wt%.

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