A process for the purification of A, A, A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene

Abstract

The embodiments of this application provide a purification method for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, comprising the following steps: S1) Crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is mixed with C1-C3 alkyl alcohol, stirred, and heated to a first temperature to dissolve, then C4-C12 straight-chain or branched alkanes are added, and the mixture is kept at the first temperature with stirring. After standing and separating into layers, the lower layer is collected; S2) A cation exchange resin is added to the lower layer of the mixture from step S1, and the mixture is kept at the second temperature with stirring. The cation exchange resin is then filtered to obtain a filtrate. The filtrate is cooled to crystallize and filtered to obtain a wet product; S3) The wet product from step S2 is mixed with pure water, stirred, and heated to a third temperature to dissolve, and then cooled to crystallize after stirring. The product is washed with low-temperature pure water and dried to obtain a refined A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. The purification method described in this application can improve the purity of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, reduce the content of metal ions, and meet the requirements of electronic chemicals.

Description

Technical Field

[0001] This application relates to the field of synthesis technology of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, specifically to a purification method for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. Background Technology

[0002] A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (also known as pyrogallol A, TPPA) can be used as a raw material in the synthesis of polymer materials such as epoxy resins and polycarbonate resins, and can also be used as a raw material or additive for photoresists. With the modern semiconductor industry demanding smaller and higher integrated circuit sizes, the requirements for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene to improve its performance and photosensitivity are becoming increasingly stringent. Therefore, there is an urgent need to develop a purification method for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene to increase its purity and reduce its metal ion content. Summary of the Invention

[0003] In view of the above-mentioned problems in the prior art, the embodiments of this application propose a purification method for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. This purification method has good purification effect and simple process, which can improve the purity of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and reduce the content of metal ions therein.

[0004] According to one aspect of this application, a method for purifying A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is provided, the purification method comprising the following steps: S1) mixing crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a first solvent, stirring, heating to a first temperature to dissolve, then adding a second solvent, maintaining the temperature at the first temperature with stirring, allowing the mixture to stand and separate into layers, and then taking the lower layer; S2) adding a cation exchanger to the lower layer of the mixture from step S1. The resin is kept at a second temperature and stirred before being filtered to obtain a filtrate of cation exchange resin. The filtrate is cooled to crystallize and then filtered to obtain a wet product. (S3) The wet product from step S2 is mixed with pure water, stirred, and heated to a third temperature to dissolve. After being kept at a temperature and stirred, it is cooled to crystallize. The product is washed with low-temperature pure water and dried to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. The first solvent is a C1-C3 alkyl alcohol, and the second solvent is a C4-C12 straight-chain or branched alkane.

[0005] In some embodiments, the weight ratio of the first solvent to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-5:1.

[0006] In some embodiments, the weight ratio of the second solvent to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-15:1.

[0007] In some embodiments, the first temperature is 50-80°C and the second temperature is 50-80°C.

[0008] In some embodiments, the cation exchange resin is a strongly acidic cation exchange resin.

[0009] In some embodiments, the strongly acidic cation exchange resin is porous or gel-type, and the strongly acidic group is a sulfonic acid group.

[0010] In some embodiments, the weight ratio of cation exchange resin to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 0.1-0.5:1.

[0011] In some embodiments, the weight ratio of pure water to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene in step S3 is 5-10:1.

[0012] In some embodiments, the third temperature is 60-80°C.

[0013] In some embodiments, the cooling rate for step S2 is 5-15℃ / h, and the temperature is lowered to -5-0℃ for crystallization; the cooling rate for step S3 is 5-15℃ / h, and the temperature is lowered to -5-0℃ for crystallization.

[0014] In some preferred embodiments, the temperature of the low-temperature pure water used for rinsing is 0-10°C.

[0015] Compared with the prior art, the above-conceptual technical solution of this application has the following advantages and effects: The purification method provided by this application has good purification effect and simple process, which can improve the purity of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and reduce the content of metal ions therein. The purification method of this application can purify and obtain electronic grade A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a purity of 99.9% and the content of various metal ions is less than 10 ppb. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this application clearer and to fully convey the scope of this application to those skilled in the art, exemplary embodiments are described in detail below. However, these exemplary embodiments can be implemented in different ways and should not be construed as being limited to the embodiments described in this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in this application are within the scope of protection of this application. It should be understood that the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other. Specific experimental or operating conditions not specified in the embodiments can be prepared under conventional conditions or according to the conditions recommended by the material supplier. Unless otherwise specified, the reagents, materials, or instruments used in the following embodiments are commercially available.

[0017] During the synthesis of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, raw materials, catalysts, and byproducts are mixed in the product, which also contains metal ions. This application provides a method for purifying A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, comprising the following steps: S1) mixing crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a first solvent, stirring, heating to a first temperature to dissolve, then adding a second solvent, maintaining the temperature at the first temperature with stirring, allowing the mixture to stand and separate into layers, and then collecting the lower layer; S2) adding a cation exchange resin to the lower layer from step S1. After stirring at a second temperature, the cation exchange resin is filtered out to obtain a filtrate. The filtrate is cooled to crystallize and filtered again to obtain a wet product. In step S3), the wet product from step S2 is mixed with pure water, stirred, and heated to a third temperature to dissolve. After stirring and maintaining the temperature, it is cooled to crystallize. The crystals are then washed with low-temperature pure water and dried to obtain a refined A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. The first solvent is a C1-C3 alkyl alcohol, and the second solvent is a C4-C12 straight-chain or branched alkane. The purification method of this application can improve the purity of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and reduce the content of metal ions.

[0018] It should be understood that the first temperature and the second temperature are temperatures that allow A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene to dissolve in the first solvent. The first temperature and the second temperature have the same range, but the actual set second temperature can be the same as or different from the first temperature. Specifically, the stirring and maintaining the temperature after adding the second solvent in step S1 can be carried out for 4-6 hours; the stirring and maintaining the temperature after adding the cation exchange resin in step S2 can be carried out for 4-6 hours; the stirring and maintaining the temperature after dissolution in step S3 can be carried out for 4-6 hours; and the drying in step S3 can be vacuum drying.

[0019] The first solvent can be methanol, ethanol, ethylene glycol, propanol, or isopropanol; the second solvent can be n-butane, cyclopentane, n-hexane, cyclohexane, n-heptane, etc.

[0020] In some embodiments, the weight ratio of the first solvent to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-5:1. When the weight ratio is less than 3, the material is not completely dissolved, which will affect the purification effect; when the weight ratio is greater than 5, the subsequent crystallization time will increase, resulting in a decrease in the yield of A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene. In some preferred embodiments, the first solvent is methanol, and the weight ratio of methanol to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3:1.

[0021] In some embodiments, the weight ratio of the second solvent to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-15:1. The second solvent has a high solubility for impurities. When the weight ratio is less than 3, the second solvent will not be able to dissolve enough impurities, leading to a decrease in product purity. When the weight ratio is greater than 15, the product purity will not be significantly improved, but will instead lead to a decrease in yield. In some preferred embodiments, the second solvent is n-hexane, and the weight ratio of n-hexane to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 8:1.

[0022] In some embodiments, the first temperature is 50-80°C and the second temperature is 50-80°C.

[0023] In some embodiments, the cation exchange resin is a strongly acidic cation exchange resin, more specifically, the strongly acidic cation exchange resin is porous or gel-type, and the strongly acidic group is a sulfonic acid group. Examples of strongly acidic cation exchange resins include, for example, Amberlite (1006FH, IRP-69, IR-118, IRC-76, IR120BHAG, etc.) and Amberlyst (15H, 15DRY, 15JWET, 16WET, 31WET, 35WET, XN1010, etc.) manufactured by Rohm and Haas; Diaion (SK1B, SK104, SK110, SK112, SK116, PK208, PK212, PK216, PK220, PK22, UBK550, PK208, PK208, UBK530, etc.) manufactured by Mitsubishi Chemical Co., Ltd.; and Dowex manufactured by Dow Chemical Co., Ltd. Monosphere (650C, 650HXC, 650HXCNG, 575CNG, 650CUPW, 650CNG, 575C, MP525C, 750C) and Dowex (HCR-NG, HCR-W2, HGRW2, MSC1C, 50, 88, 88MB, etc.); Bayer's MP-62, etc.

[0024] In some embodiments, the weight ratio of cation exchange resin to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 0.1-0.5:1. When the weight ratio of cation exchange resin to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is less than 0.1, the resin has insufficient adsorption sites for metal ions, leading to an increase in metal ion content. When the weight ratio of cation exchange resin to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is greater than 0.5, the metal ion content remains almost unchanged, but the increased adsorption of the resin by the product leads to a decrease in yield. In some preferred embodiments, the weight ratio of cation exchange resin to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 0.2:1.

[0025] In some embodiments, the weight ratio of pure water to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene in step S3 is 5-10:1. When the weight ratio of pure water to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is less than 5, the solubility of pure water for free metal ions is insufficient, leading to an increase in the metal ion content. When the weight ratio of pure water to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is greater than 10, the effect on the metal ion content hardly changes, but the crystallization effect deteriorates. A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene does not have time to grow into crystals and directly becomes an oily substance or amorphous powder, which is prone to encapsulating impurities, resulting in a deterioration in crystal form, purity, and yield. In some preferred embodiments, the weight ratio of pure water to crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 8:1.

[0026] In some embodiments, the third temperature is 60-80°C.

[0027] In some embodiments, the cooling rate for crystallization in step S2 is 5-15°C / h, cooling to -5-0°C for crystallization; the cooling rate for crystallization in step S3 is 5-15°C / h, cooling to -5-0°C for crystallization. Slow, programmed cooling is beneficial for forming crystals of higher purity, promoting the formation of large crystals with uniform particle size and fewer encapsulated impurities, thereby improving product purity and filtration performance.

[0028] In some embodiments, the temperature of the low-temperature pure water used for rinsing is 0-10°C. Within this temperature range, the solubility of pure water for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is extremely low, allowing for the rinsing removal of residual metal ions on the surface of the material crystals without material loss. Pure water temperatures above 10°C will lead to a decrease in yield. In a preferred embodiment, the temperature of the low-temperature pure water used for rinsing can be selected as 0-5°C.

[0029] This application provides a simplified purification method for A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene using a three-step synergistic process: layered extraction, resin adsorption for deep purification, and directional crystallization (controlling the crystallization process: temperature, cooling rate, and solvent used). This method features a simple process flow while maintaining excellent purification results. It is particularly outstanding in terms of metal ion removal efficiency and product yield, providing a more optimized technical solution for the industrial production of high-end electronic chemicals. The purification method of this application can obtain electronic-grade A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a purity of 99.9% and the content of various metal ions less than 10 ppb.

[0030] The present application will be described in more detail below through examples.

[0031] Example 1

[0032] In a clean apparatus, 1000g of crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and 3000g of methanol (first solvent) were added, mixed, stirred, and heated to 60°C. After dissolution, 8000g of n-hexane (second solvent) was added, and the mixture was kept at 60°C and stirred for 6 hours. After standing and separating into layers, the lower layer was collected. 200g of porous strong acid cation exchange resin (HA-8G type resin produced by Xi'an Hairun New Materials Co., Ltd.) was added to the lower layer, and the mixture was kept at 70°C and stirred for 6 hours. The resin was filtered out to obtain a filtrate. The filtrate was cooled to -5°C at a programmed rate of 15°C / hour to slowly crystallize, and the wet product was obtained by filtration. The wet product was added to 8000g of pure water, mixed, stirred and heated to 70℃ to dissolve. After dissolving, it was kept at this temperature and stirred for 6 hours. The temperature was then reduced to -5℃ at a rate of 15℃ / hour to crystallize. The product was filtered, washed with pure water at 5℃, and then dried under vacuum to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a yield of 83.7% and a purity of 99.9%. The content of various metal ions was all below 10 ppb.

[0033] Example 2

[0034] The only difference from Example 1 is that the first solvent is isopropanol and the second solvent is n-butane. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 82.6% and a purity of 99.2%, with all metal ions containing less than 10 ppb.

[0035] Example 3

[0036] The only difference from Example 1 is that the first solvent is n-propanol and the second solvent is n-dodecane. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 81.2% and a purity of 99.4%, with all metal ions containing less than 10 ppb.

[0037] Example 4

[0038] The only difference from Example 1 was that the mass of the first solvent was 5000g. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 81.8% and a purity of 99.9%, with all metal ions containing less than 10 ppb.

[0039] Example 5

[0040] The only difference from Example 1 was that the mass of the second solvent was 3000g. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 82.6% and a purity of 98.6%, with all metal ions containing less than 10 ppb.

[0041] Example 6

[0042] The only difference from Example 1 was that the mass of the second solvent was 15000g. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 80.7% and a purity of 99.9%, with all metal ions containing less than 10 ppb.

[0043] Example 7

[0044] The only difference from Example 1 is that in step S1, the mixture is stirred and heated to 50°C; in step S2, the mixture is stirred and kept at 50°C. Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is obtained with a yield of 81.1% and a purity of 99.3%, with all metal ions containing less than 10 ppb.

[0045] Example 8

[0046] The only difference from Example 1 is that in step S1, the mixture is stirred and heated to 80°C; in step S2, the mixture is stirred and kept at 80°C. Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is obtained with a yield of 81.8% and a purity of 99.2%, with all metal ions containing less than 10 ppb.

[0047] Example 9

[0048] The only difference from Example 1 is that the added resin is a gel-type strong acid cation exchange resin (Mitsubishi Chemical Diaion SK1B type resin). Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene was obtained with a yield of 82.8%, a purity of 99.9%, and an average content of 13 ppb for various metal ions.

[0049] Example 10

[0050] The only difference from Example 1 was that the mass of the added resin was 100g. Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene was obtained with a yield of 83.3%, a purity of 99.9%, and an average content of 13 ppb for various metal ions.

[0051] Example 11

[0052] The only difference from Example 1 was that the mass of the added resin was 500g. Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene was obtained with a yield of 82.4% and a purity of 99.9%, with the contents of all metal ions below 10 ppb.

[0053] Example 12

[0054] The only difference from Example 1 is that the cooling rate in step S2 is 5°C / h. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 83.6% and a purity of 99.6%, with all metal ions containing less than 10 ppb.

[0055] Example 13

[0056] The only difference from Example 1 is that the cooling rate in step S3 is 5°C / h. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 83.2% and a purity of 99.5%, with all metal ions containing less than 10 ppb.

[0057] Example 14

[0058] The only difference from Example 1 is that in step S2, the temperature was lowered to 0°C for crystallization, and in step S3, the temperature was lowered to 0°C for crystallization. Finally, after vacuum drying, A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene was obtained with a yield of 79.2% and a purity of 98.6%, with the content of various metal ions all below 10 ppb.

[0059] Example 15

[0060] The only difference from Example 1 is that in step S3, the wet product is added to 5000g of pure water. Finally, vacuum drying yields A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 80.3%, a purity of 99.9%, and an average content of 14 ppb for various metal ions.

[0061] Example 16

[0062] The only difference from Example 1 is that in step S3, the wet product is added to 10,000g of pure water. Finally, vacuum drying yields A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 79.6% and a purity of 99.9%, and the contents of various metal ions are all below 10 ppb.

[0063] Example 17

[0064] The only difference from Example 1 is that after adding pure water in step S3, the mixture is stirred and heated to 60°C. Finally, vacuum drying yields A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 81.3% and a purity of 99.9%, and the contents of various metal ions are all below 10 ppb.

[0065] Example 18

[0066] The only difference from Example 1 is that after adding pure water in step S3, the mixture is stirred and heated to 80°C. Finally, vacuum drying yields A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 82.4% and a purity of 99.9%, and the contents of various metal ions are all below 10 ppb.

[0067] Example 19

[0068] The only difference from Example 1 is that the temperature of the pure water used for rinsing in step S3 is 0°C. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 83.3% and a purity of 99.9%, with all metal ions containing less than 10 ppb.

[0069] Example 20

[0070] The only difference from Example 1 is that the temperature of the pure water used for rinsing in step S3 is 10°C. Finally, vacuum drying yielded A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 82.7% and a purity of 99.9%, with all metal ion contents below 10 ppb.

[0071] Comparative Example 1

[0072] The following step, S1, is missing: In a clean apparatus, 1000g of crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and 3000g of methanol (first solvent) are added, mixed, stirred, and heated to 60°C. After dissolution, 200g of porous strong acid cation exchange resin (HA-8G type resin produced by Xi'an Hairun New Materials Co., Ltd.) is added to the solution. The solution is kept at 70°C and stirred for 6 hours. The resin is filtered out to obtain a filtrate. The filtrate is cooled to -5°C at a programmed rate of 15°C / hour to slowly crystallize. The wet product is then obtained by filtration. The wet product was added to 8000g of pure water, mixed, stirred, and heated to 70℃. After dissolving, it was kept at this temperature and stirred for 6 hours. The temperature was then lowered to -5℃ at a rate of 15℃ / hour to crystallize. The product was filtered, washed with pure water at 5℃, and then dried under vacuum to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, with a yield of 83.6% and a purity of 98.3%. The content of various metal ions was all <10ppb.

[0073] Comparative Example 2

[0074] Step S2 involves passing the product through an ion exchange resin column, rather than stirring and maintaining the product with the ion exchange resin for a period of time: In a clean apparatus, 1000g of crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and 3000g of methanol (first solvent) are added, mixed, stirred, and heated to 60°C. After dissolution, 8000g of n-hexane (second solvent) is added, and the mixture is stirred and maintained at 60°C for 6 hours. After standing and separating into layers, the lower layer is collected. The lower layer is then passed through a resin column containing 200g of porous, strongly acidic cation exchange resin (HA-8G type resin produced by Xi'an Hairun New Materials Co., Ltd.). After passing through the resin column, a filtrate is obtained. The filtrate is then cooled to -5°C at a programmed rate of 15°C / hour to slowly crystallize, and the wet product is obtained by filtration. The wet product was added to 8000g of pure water, mixed, stirred and heated to 70℃ to dissolve. After dissolving, it was kept at this temperature and stirred for 6 hours. The temperature was then reduced to -5℃ at a rate of 15℃ / hour to crystallize. The product was filtered, washed with pure water at 5℃, and then dried under vacuum to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a yield of 83.2%, a purity of 99.7%, and an average content of 34 ppb for various metal ions.

[0075] Comparative Example 3

[0076] Step S2 involves directly precipitating TPPA from the resin filtrate in pure water instead of undergoing two crystallization processes: In a clean apparatus, 1000g of crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene and 3000g of methanol (first solvent) are added, mixed, stirred, and heated to 60°C. After dissolution, 8000g of n-hexane (second solvent) is added, and the mixture is kept at 60°C and stirred for 6 hours. After standing and separating into layers, the lower layer is collected. 200g of porous strong acid cation exchange resin (HA-8G type resin produced by Xi'an Hairun New Materials Co., Ltd.) was added to the lower layer liquid. The mixture was kept at 70℃ and stirred for 6 hours. The resin was filtered out to obtain a filtrate. The filtrate was poured into pure water to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene precipitate. The precipitate was dried under vacuum to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with a yield of 83.3%, a purity of 99.2%, and an average content of various metal ions of 23 ppb.

[0077] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for purifying A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene, characterized in that, Includes the following steps: S1) Mix crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene with the first solvent, stir, heat to the first temperature to dissolve, then add the second solvent, keep warm and stir at the first temperature, let stand and separate into layers, and then take the lower layer. S2) Add cation exchange resin to the lower layer of liquid in step S1, keep it warm and stir at the second temperature, filter out the cation exchange resin to obtain filtrate, cool the filtrate to precipitate crystals, filter to obtain wet product. S3) The wet product from step S2 is mixed with pure water, stirred, and heated to a third temperature to dissolve. After stirring and maintaining the temperature, the product is cooled to crystallize. The product is then rinsed with low-temperature pure water and dried to obtain A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (POP). The first solvent is a C1-C3 alkyl alcohol, and the second solvent is a C4-C12 straight-chain or branched alkane.

2. The purification method according to claim 1, characterized in that, The weight ratio of the first solvent to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-5:

1.

3. The purification method according to claim 1, characterized in that, The weight ratio of the second solvent to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 3-15:

1.

4. The purification method according to claim 1, characterized in that, The first temperature is 50-80℃, and the second temperature is 50-80℃.

5. The purification method according to claim 1, characterized in that, The cation exchange resin is a strongly acidic cation exchange resin.

6. The purification method according to claim 5, characterized in that, The strongly acidic cation exchange resin is porous or gel-type, and the strongly acidic group is a sulfonic acid group.

7. The purification method according to claim 1, characterized in that, The weight ratio of the cation exchange resin to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 0.1-0.5:

1.

8. The purification method according to claim 1, characterized in that, The third temperature is 60-80℃.

9. The purification method according to claim 1, characterized in that, The weight ratio of the pure water in step S3 to the crude A,A,A'-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene is 5-10:

1.

10. The purification method according to claim 1, characterized in that, The cooling rate for step S2, which involves cooling down to -5 to 0°C, is 5-15°C / h, and the crystallization is carried out at -5 to 0°C. The cooling rate for step S3, which involves cooling down to -5 to 0°C, is 5-15°C / h, and the crystallization is carried out at -5 to 0°C. Preferably, the temperature of the low-temperature pure water used for rinsing is 0-10℃.