Method for preparing high-purity electronic-grade bisphenol f type epoxy resin by tri-modified mesoporous SBA-15

Abstract

This application discloses a method for preparing high-purity electronic-grade bisphenol F epoxy resin using three-modified mesoporous SBA-15, relating to the field of materials preparation, including obtaining mesoporous SBA-15 with a pore diameter of 9nm~11nm and a specific surface area of ​​600m². 2 / g~800m 2 / g, the mesoporous SBA-15 is added to mercaptohexyltriethoxysilane or mercaptooctyltriethoxysilane to obtain monomodified mesoporous SBA-15; the monomodified mesoporous SBA-15 is added to 3-triethoxysilylpropyltrimethylammonium chloride to obtain doubly modified mesoporous SBA-15; the doubly modified mesoporous SBA-15 is added to 3-propanesulfonic acid triethoxysilane or 4-sulfonate butyltriethoxysilane to obtain trimodified mesoporous SBA-15. This method, through the synergistic effect of the trifunctional groups, ultimately prepares a high-purity bisphenol F type epoxy resin that meets the requirements for electronic-grade applications.

Description

Technical Field

[0001] This application relates to the field of materials preparation, and more particularly to a method for preparing high-purity electronic-grade bisphenol F type epoxy resin using three-modified mesoporous SBA-15. Background Technology

[0002] Epoxy resins are widely used in high-end electronic fields such as electronic packaging, copper-clad laminates, and semiconductor molding compounds due to their excellent mechanical strength, electrical insulation, chemical corrosion resistance, and bonding properties. Among them, bisphenol F epoxy resin (BPF-ER), due to the presence of flexible methylene bridge chains in its molecular structure, has lower viscosity, better resistance to damp heat, and lower dielectric loss than bisphenol A epoxy resin, and has become one of the preferred matrix resins for high-frequency and high-speed printed circuit boards, advanced packaging substrates, and high-density interconnect (HDI) interlayer insulation materials.

[0003] The traditional industrialization route for bisphenol F type epoxy resin usually adopts a two-step method: first, bisphenol F is prepared by condensing phenol and formaldehyde with inorganic acid (such as hydrochloric acid or sulfuric acid) or solid acid molecular sieve catalyzed by inorganic acid (such as hydrochloric acid or sulfuric acid) or solid acid molecular sieve, and then etherification and cyclization reaction with epichlorohydrin (ECH) under alkaline catalysis to obtain epoxy resin.

[0004] However, the catalyst lacks directional regulation. The hydroxyl group of phenol acts as an ortho- and para-directing group, which simultaneously induces formaldehyde to attack the 2- and 4-positions. This results in the 4,4'-isomer accounting for only 50% to 60%, requiring multiple purification steps to improve purity. This not only increases process complexity and production costs but also reduces product yield. Furthermore, the homogeneous acidic catalyst is difficult to separate from the reaction system and tends to remain in the product, leading to excessive total chlorine and metal ion content in bisphenol F. Consequently, the epoxy resin prepared subsequently cannot meet the electronic grade requirements, i.e., total chlorine ≤ 400 ppm and metal ion ≤ 5 ppm. Summary of the Invention

[0005] In view of this, this application provides a method for preparing high-purity electronic-grade bisphenol F type epoxy resin based on trimodified mesoporous SBA-15. This method uses trimodified mesoporous SBA-15 as a heterogeneous catalyst. Through the synergistic effect of the three functional groups of mercapto, quaternary ammonium salt and sulfonic acid group, high directional selectivity of 4,4'-isomers is achieved in the synthesis of bisphenol F (i.e., directional conversion of greater than or equal to 85%). Moreover, the heterogeneous catalyst can be separated and recovered by simple filtration after the reaction, effectively avoiding catalyst residue in the product system, greatly improving the purity of bisphenol F and subsequent epoxy resin products, and finally preparing high-purity bisphenol F type epoxy resin that meets the requirements of electronic-grade applications.

[0006] In a first aspect, this application provides a method for preparing high-purity electronic-grade bisphenol F epoxy resin using three-modified mesoporous SBA-15, comprising at least the following steps: Step I: Obtaining mesoporous SBA-15 with a pore diameter of 9~11 nm and a specific surface area of ​​600~800 m². 2 / g. Pore diameter within the above range is beneficial for providing sufficient inner wall space for subsequent functional group grafting, and can also avoid long-chain alkyl entanglement blocking the pores; further controlling the specific surface area within the above range is beneficial for increasing the functional group grafting density, ensuring the uniform distribution of catalytic active sites, spatial shielding sites and formaldehyde complexation sites, and laying the structural foundation for the synergistic effect of the three functional groups.

[0007] Step II: First Modification: The mesoporous SBA-15 was dispersed in anhydrous toluene, and a long-chain alkyl mercaptosilane coupling agent was added to react and obtain monomodified mesoporous SBA-15 with a mercapto grafting density of 0.8~1.2 mmol / g (based on the mass of the mesoporous SBA-15 carrier). Covalent grafting was formed by the condensation reaction between silanoxy groups and hydroxyl groups on the surface of the mesoporous SBA-15 carrier, fixing the long-chain alkyl mercapto groups to the inner wall of the pores. The mercapto grafting density was controlled within the above range to ensure that the long-chain alkyl groups form a uniform spatial barrier within the pores. Furthermore, the mercapto groups can form intermolecular hydrogen bonds with the hydroxyl groups of phenol in subsequent reactions, thus fixing the phenol molecule's orientation. This ensures that the 4-position of phenol faces the center of the pores, while the 2-position is physically shielded by the long-chain alkyl groups, blocking ortho-position side reactions from a spatial perspective.

[0008] Step III: Second Modification: The single-modified mesoporous SBA-15 was dispersed in anhydrous ethanol, and a quaternary ammonium salt silane coupling agent was added to react and obtain double-modified mesoporous SBA-15. The grafting molar ratio of quaternary ammonium salt to mercapto groups was 1:(1.8~2.2). Controlling the grafting molar ratio of quaternary ammonium salt to mercapto groups within the above range is beneficial for the uniform distribution of quaternary ammonium salt in the mercapto group interstices. The quaternary ammonium salt groups can form ion-dipole complexes with the carbonyl groups of formaldehyde molecules. On the one hand, this improves the solubility of formaldehyde in the weakly polar toluene system. On the other hand, the complexation effect can regulate the electrophilic activity of formaldehyde and enhance its attack ability on the 4-position of phenol.

[0009] Step IV: Third Modification: The double-modified mesoporous SBA-15 was dispersed in anhydrous dichloromethane, and a sulfonic acid silane coupling agent was added to react and obtain a triple-modified mesoporous SBA-15. The grafting molar ratio of sulfonic acid groups to mercapto groups was 1:(0.8~1.2). The sulfonic acid silane coupling agent was covalently grafted and fixed to the inner wall of the pores of the support. Controlling the grafting molar ratio of sulfonic acid groups to mercapto groups within the above range facilitates the formation of a synergistic catalytic system by the spatial barrier formed by the sulfonic acid group and the complexation site formed by the quaternary ammonium salt, achieving high 4,4'-isomer selectivity and obtaining high-purity bisphenol F with a 4,4'-isomer content ≥85%, total chlorine ≤100ppm, and metal ion ≤5ppm.

[0010] Step V: Phenol and the modified mesoporous SBA-15 were added to a reaction vessel, followed by toluene. The mixture was stirred and dispersed until the reaction system temperature dropped to 25-35°C. A 37% formaldehyde solution was added dropwise, and the reaction was carried out at a constant temperature for 2-3 hours. The mixture was then frozen at -5 to 0°C for 12-16 hours and filtered to obtain high-purity electronic-grade bisphenol F epoxy resin (total chlorine ≤ 100 ppm, metal ions ≤ 5 ppm). The modified mesoporous SBA-15, acting as a heterogeneous catalyst, catalyzed the directional formation of high-4,4'-isomer bisphenol F (≥ 85%) in a low-temperature (25-35°C) and weakly polar toluene system. After filtration and separation, the total chlorine content was ≤ 100 ppm, and the metal ion content (Na₂O₃) was ≤ 5 ppm. + / K + The total content is ≤5ppm. The high content of 4,4'-isomers lays the foundation for the subsequent preparation of high-performance epoxy resins, which can make the crosslinking network of epoxy resins more compact after curing, with a glass transition temperature (Tg) ≥130℃ and water absorption ≤0.1%.

[0011] This application selects mesoporous SBA-15 with suitable pore diameter and specific surface area as a carrier. By setting spatial barriers within the pores to block the 2-position of phenol at the spatial level, quaternary ammonium salt is uniformly distributed in the inter-mercapto-group spaces to form an ion-dipole complex with the carbonyl group of formaldehyde molecule. This allows for efficient synergy between the spatial barriers formed by sulfonic acid groups and mercapto-group spaces, and the complexation sites formed by quaternary ammonium salt. The sulfonic acid groups are distributed in the inter-mercapto-group spaces, and their acidic sites are aligned with the exposed 4-position of phenol. This ensures that the hydroxymethyl carbocation can only preferentially attack the 4-position of phenol within the steric hindrance range to undergo an electrophilic substitution reaction, thus blocking the path to the 2-position at the spatial level. This application uses a low temperature of 25~35℃ and a weakly polar toluene solvent system. Under this system, the three-modified mesoporous SBA-15 is conducive to maintaining its own structural stability, ultimately achieving high 4,4'-isomer selectivity, with the total content of side isomers (2,4'-position, 2,2'-position) ≤15% and polymeric byproducts ≤1%.

[0012] In some embodiments, the process further includes: Step VI: Etherification reaction: Bisphenol F and epichlorohydrin are mixed, and benzyltriethylammonium chloride is added as an etherification catalyst to react and obtain an etherified product; and / or, Step VII: Cycling reaction: NaOH aqueous solution is added dropwise to the etherified product, the molar ratio of NaOH to the high-purity bisphenol F is (1.02~1.05):1, and the reaction is maintained at a constant temperature for 1~1.5h after the addition is completed to obtain a cyclized product; and / or, Step VIII: Post-treatment purification: The cyclized product is allowed to stand and separate into layers, the aqueous phase is removed, the organic phase is subjected to two alkaline washes and water washes until neutral, residual solvent and low-boiling substances are removed under reduced pressure, and then metal ions are removed by ion exchange resin treatment to obtain high-purity electronic-grade bisphenol F type epoxy resin.

[0013] The two active phenolic hydroxyl groups in the high 4,4'-isomer bisphenol F prepared through steps I to V can rapidly dissociate into phenoxy anions under the action of benzyltriethylammonium chloride, attacking the methylene carbon adjacent to the epoxy ring in the epichlorohydrin molecule to generate an etherified product. Then, an aqueous solution of NaOH is added dropwise to the etherified product. NaOH, as a strong base, can dissociate into OH-. - The hydroxyl group (-OH) in the etherified product preferentially captures a proton, forming an oxonium. This oxonium then attacks the adjacent chlorinated carbon atom via intramolecular nucleophilic attack, removing the HCl molecule and yielding the cyclized product. In particular, the ≥85% 4,4'-isomer in bisphenol F enables the epoxy resin to form a dense and uniform cross-linked network after curing, ultimately achieving excellent heat and humidity resistance with a Tg ≥130℃ and a water absorption rate ≤0.1%.

[0014] In some embodiments, the high-purity electronic-grade bisphenol F epoxy resin has an epoxy value greater than or equal to 0.53 eq / 100g, a total chlorine content less than or equal to 400 ppm, and a viscosity at 25°C less than or equal to 2000 mPa·s; and / or, the bisphenol F electronic-grade epoxy resin has a glass transition temperature ≥130°C and a water absorption rate ≤0.1%.

[0015] In some embodiments, in step II, the long-chain alkyl mercaptosilane coupling agent is mercaptohexyltriethoxysilane or mercaptooctyltriethoxysilane, and its mass ratio to mesoporous SBA-15 is 1:(3~5); and / or, in step III, the quaternary ammonium salt silane coupling agent is 3-triethoxysilylpropyltrimethylammonium chloride, and its grafting density is controlled at 0.3~0.6 mmol / g; and / or, in step IV, the sulfonate silane coupling agent is 3-mercaptopropylsulfonatetriethoxysilane or 4-sulfonatebutyltriethoxysilane, and its grafting density is controlled at 0.6~1.5 mmol / g; and / or, in step V, the mass ratio of phenol, the three-modified mesoporous SBA-15 and the toluene is 1:(0.08~0.12):(1.5~2.0), and the mass ratio of phenol and the formaldehyde solution is 1:(0.26~0.30).

[0016] In some embodiments, in step II, the reaction conditions include: reflux for 12-16 hours under nitrogen protection at an ambient temperature of 80-90°C, followed by filtration, washing with toluene 3-5 times, and vacuum drying after the reaction is completed.

[0017] In some embodiments, in step III, the reaction conditions include: constant temperature stirring reaction at an ambient temperature of 40~50℃ for 8~10h, filtration, washing with ethanol 3~5 times, and vacuum drying at 100~110℃ for 6~8h.

[0018] In some embodiments, in step IV, the reaction conditions include: stirring at a constant temperature of 50-60°C for 6-8 hours under nitrogen protection, followed by filtration, washing with dichloromethane 3-5 times, and vacuum drying at 80-90°C for 4-6 hours.

[0019] In some embodiments, in step VI, the molar ratio of the high-purity bisphenol F to the epichlorohydrin is 1:(6~10), and the etherification catalyst is 0.8~1.2% of the mass of the high-purity bisphenol F. The reaction conditions include: under nitrogen protection, at an ambient temperature of 70~80°C, for 4~6 hours.

[0020] In some embodiments, in step VII, a 40% NaOH aqueous solution is added dropwise in three stages under a vacuum of 0.08~0.09 MPa, and the temperature of the heat preservation reaction is 80~90℃; and / or, the volume ratio of the NaOH aqueous solution added in the three stages is 1:2:1, the dropping rate in the first stage is 0.5~1 mL / min, the dropping rate in the second stage is 1~1.5 mL / min, and the dropping rate in the third stage is 0.5~1 mL / min.

[0021] In some embodiments, the amount of anhydrous toluene is 8 to 10 times the mass of the mesoporous SBA-15; and / or, the amount of anhydrous ethanol is 6 to 8 times the mass of the single-modified mesoporous SBA-15, and the pH of the reaction system is 6 to 7; and / or, the amount of anhydrous dichloromethane is 7 to 9 times the mass of the double-modified mesoporous SBA-15. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] Preparation of mercaptohexyltriethoxysilane: 6-chlorohexyltriethoxysilane and anhydrous sodium hydrosulfide were used as raw materials, and anhydrous DMF was used as solvent. The nucleophilic substitution reaction was carried out under nitrogen protection at 60-65℃ for 8-10 h to generate the target product. After the reaction, the product was filtered to remove salt. The filtrate was extracted with ethanol-water and dried with anhydrous magnesium sulfate to remove impurities and water. Finally, the product was purified by vacuum gradient distillation (vacuum degree 0.095-0.098MPa, 120-130℃), and the fraction was collected to obtain the high-purity product.

[0024] Preparation of 3-propanesulfonic acid triethoxysilane: 3-mercaptopropyltriethoxysilane and m-chloroperoxybenzoic acid (m-CPBA) were used as raw materials, and anhydrous dichloromethane was used as solvent. The sulfonation reaction was carried out under nitrogen protection and low temperature conditions of 0~5℃ for 4~6h. After the reaction, the mixture was neutralized to neutral with alkali solution. The aqueous phase was discarded by separation, and the organic phase was dried with anhydrous magnesium sulfate to remove water. Then, it was purified by vacuum distillation (vacuum degree 0.09~0.095MPa, 130~140℃). The fraction was collected to obtain the target product.

[0025] A method for preparing high-purity electronic-grade bisphenol F type epoxy resin using modified mesoporous SBA-15.

[0026] Includes the following steps:

[0027] Step I: Obtain mesoporous SBA-15 with a pore diameter of 9~11 nm and a specific surface area of ​​600~800 m². 2 / g. For example, the mesoporous SBA-15 has a pore diameter of 9nm, 10nm, 11nm, or any two of the above values, and a specific surface area of ​​600m². 2 / g、650m 2 / g、700m 2 / g、750m 2 / g、800m 2 / g or the range between any two of the above values.

[0028] Step II: First Modification: The mesoporous SBA-15 is dispersed in anhydrous toluene, and a long-chain alkyl mercaptosilane coupling agent is added to react and obtain monomodified mesoporous SBA-15 with a mercapto grafting density of 0.8~1.2 mmol / g. Exemplarily, the mercapto grafting density is 0.8 mmol / g, 0.9 mmol / g, 1.0 mmol / g, 1.1 mmol / g, 1.2 mmol / g, or any two of the above values.

[0029] Step III: Second Modification: The single-modified mesoporous SBA-15 is dispersed in anhydrous ethanol, and a quaternary ammonium salt silane coupling agent is added to react and obtain double-modified mesoporous SBA-15. The grafting molar ratio of quaternary ammonium salt to mercapto group is 1:(1.8~2.2). For example, the grafting molar ratio of quaternary ammonium salt to mercapto group is 1:1.8, 1:1.9, 1:2.0, 1:2.1, 1:2.2 or any two of the above values.

[0030] Step IV: Third modification: The double-modified mesoporous SBA-15 is dispersed in anhydrous dichloromethane, and a sulfonic acid-based silane coupling agent is added to react and obtain triple-modified mesoporous SBA-15. The grafting molar ratio of sulfonic acid groups to mercapto groups is 1:(0.8~1.2). For example, the grafting molar ratio of sulfonic acid groups to mercapto groups is 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, or any two of the above values.

[0031] Step V: Add phenol and the modified mesoporous SBA-15 to the reactor, then add toluene, stir and disperse until the reaction system temperature drops to 25~35℃, add 37% formaldehyde solution dropwise, react at a constant temperature for 2~3h, freeze and crystallize at -5~0℃ for 12~16h, filter, and obtain bisphenol F.

[0032] After steps I to V, high-purity bisphenol F with a 4,4'-isomer content ≥85%, total chlorine ≤100ppm, and metal ion content ≤5ppm is obtained.

[0033] Step VI: Etherification reaction: Bisphenol F and epichlorohydrin are mixed, and benzyltriethylammonium chloride is added as an etherification catalyst to react and obtain the etherified product. The molar ratio of bisphenol F to epichlorohydrin is 1:(6~10), the etherification catalyst is 0.8~1.2% of the mass of bisphenol F, and the reaction conditions include: under nitrogen protection, at an ambient temperature of 70~80℃, the reaction is carried out for 4~6 hours.

[0034] Step VII: Cyclization reaction: NaOH aqueous solution is added dropwise to the etherified product, with a molar ratio of NaOH to bisphenol F of (1.02~1.05):1. After the addition is complete, the reaction is maintained at this temperature for 1~1.5 h to obtain the cyclized product. Under a vacuum of 0.08~0.09 MPa, a 40% (w / w) NaOH aqueous solution is added dropwise in three stages. The temperature of the reaction is maintained at 80~90℃. The volume ratio of the NaOH aqueous solution added in the three stages is 1:2:1. The dropping rate is 0.5~1 mL / min in the first stage, 1~1.5 mL / min in the second stage, and 0.5~1 mL / min in the third stage.

[0035] Step VIII: Post-processing purification: The cyclized product is allowed to stand and separate into layers. The aqueous phase is removed, and the organic phase is subjected to two alkaline washes and water washes until neutral. The residual solvent and low-boiling substances are removed under reduced pressure. Then, the product is treated with ion exchange resin to remove metal ions, thereby obtaining high-purity electronic-grade bisphenol F type epoxy resin.

[0036] Following steps VI to VIII, high-purity electronic-grade bisphenol F epoxy resin (total chlorine ≤ 100 ppm, metal ions ≤ 5 ppm) is obtained. Due to the high purity and low impurity content of bisphenol F, the etherification reaction does not require dealing with interference from side isomers, and the conversion rate can reach over 98%. Furthermore, the cyclization reaction can use a low alkali excess ratio of (1.02~1.05):1 to avoid hydrolysis of epoxy groups caused by excessive alkali, ensuring an epoxy value ≥ 0.53 eq / 100g. With subsequent purification, the total chlorine content of the epoxy resin can be ≤ 400 ppm and the metal ion content ≤ 5 ppm, meeting the stringent impurity requirements for electronic-grade products.

[0037] In step II, the long-chain alkyl mercaptosilane coupling agent is mercaptohexyltriethoxysilane or mercaptooctyltriethoxysilane, and its mass ratio to mesoporous SBA-15 is 1:(3~5). Exemplarily, the mass ratio of the long-chain alkyl mercaptosilane coupling agent to mesoporous SBA-15 is 1:3, 1:3.5, 1:4, 1:4.5, or 1:5, which is a range between any two of the above values.

[0038] In step III, the quaternary ammonium silane coupling agent is 3-triethoxysilylpropyltrimethylammonium chloride, and its grafting density is 0.4~0.6 mmol / g. Exemplarily, the grafting density of the quaternary ammonium silane coupling agent is 0.4 mmol / g, 0.5 mmol / g, or 0.6 mmol / g, which is a range between any two of the above values.

[0039] In step IV, the sulfonate-based silane coupling agent is 3-mercaptopropylsulfonatetriethoxysilane or 4-sulfonatebutyltriethoxysilane, with a grafting density of 0.8~1.2 mmol / g. Exemplarily, the grafting density of the sulfonate-based silane coupling agent is 0.8 mmol / g, 0.9 mmol / g, 1.0 mmol / g, 1.1 mmol / g, or 1.2 mmol / g, which is a range between any two of the above values.

[0040] In step V, the mass ratio of phenol, the three-modified mesoporous SBA-15 and the toluene is 1:(0.08~0.12):(1.5~2.0), and the mass ratio of phenol and the formaldehyde solution is 1:(0.26~0.30).

[0041] In step VI, the molar ratio of bisphenol F to epichlorohydrin is 1:(6~10), and the etherification catalyst is 0.8~1.2% of the mass of bisphenol F.

[0042] The following specific embodiments illustrate a method for preparing high-purity electronic-grade bisphenol F epoxy resin using modified mesoporous SBA-15. Those skilled in the art will understand that the preparation method described in this application is merely an example, and any other suitable preparation method is within the scope of this application.

[0043] All raw materials were commercially available industrial-grade products. Mesoporous SBA-15 was purchased from Aladdin Reagents. The purity of the silane coupling agent was ≥98%, and the purity of epichlorohydrin was ≥99.5%. All reactions were carried out under nitrogen protection (unless otherwise specified).

[0044] The product performance testing methods are as follows: the proportion of 4,4'-isomers was detected by high performance liquid chromatography (HPLC), the total chlorine content was detected by microcoulometric titration, the metal ion content was detected by inductively coupled plasma mass spectrometry (ICP-MS), the epoxy value was detected by hydrochloric acid-acetone titration, the glass transition temperature (Tg) was detected by differential scanning calorimetry (DSC), and the viscosity was detected by rotational viscometer.

[0045] Example 1: Step I: Select a pore diameter of 9 nm and a specific surface area of ​​600 m². 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0046] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 80g of anhydrous toluene, add 2g of mercaptohexyltriethoxysilane, and reflux at 80℃ for 12h under nitrogen protection. After the reaction is complete, filter, wash the filter cake three times with anhydrous toluene, and dry it under vacuum at 80℃ for 6h to obtain mercapto-modified SBA-15 (i.e., monomodified mesoporous SBA-15). The mercapto grafting density was measured to be 0.8mmol / g.

[0047] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 60g of anhydrous ethanol, adjust the pH of the reaction system to 6, add 3-triethoxysilylpropyltrimethylammonium chloride, and control the molar ratio of quaternary ammonium salt to mercapto graft to 1:2.2. Stir the reaction at 40℃ for 8h. After filtration, wash three times with anhydrous ethanol and dry under vacuum at 100℃ for 6h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.36mmol / g.

[0048] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 70g of anhydrous dichloromethane, add 3-propanesulfonic acid triethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:1.2, and react under nitrogen protection at 50℃ with stirring for 6h. After filtration, wash three times with anhydrous dichloromethane, and dry under vacuum at 80℃ for 4h to obtain triple-modified mesoporous SBA-15. The sulfonic acid group grafting density is 0.67mmol / g.

[0049] Step V: Add 100g phenol, 8g of modified mesoporous SBA-15, and 150g toluene to the reactor. Stir and disperse until the system temperature drops to 25℃. Add 26g of 37% formaldehyde solution dropwise and react at a constant temperature for 2 hours. After the reaction, filter to recover the catalyst. Place the filtrate at -5℃ for 12 hours to crystallize. Filter, wash the filter cake twice with toluene, and vacuum dry at 80℃ for 4 hours to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 85%, the total chlorine content is 95ppm, and the total metal ion content is 4ppm.

[0050] Step VI: Take 50g of the above high-purity bisphenol F, mix it with 300g of epichlorohydrin, add 0.4g of benzyltriethylammonium chloride, and react at 70°C for 4h under nitrogen protection to obtain the etherified product.

[0051] Step VII: Under vacuum of 0.08 MPa and 80 °C, a 40% NaOH aqueous solution was added dropwise to the etherification product in three stages. The molar ratio of NaOH to bisphenol F was 1.02:1, the volume ratio of the three stages was 1:2:1, and the dropping rates were 0.5 mL / min, 1 mL / min, and 0.5 mL / min, respectively. After the addition was completed, the reaction was kept at the temperature for 1 h to obtain the cyclized product.

[0052] Step VIII: The cyclization product is allowed to stand and separate into layers. The aqueous phase is removed, and the organic phase is subjected to a second alkaline wash (using a 5% NaOH aqueous solution, with an organic phase to alkaline solution volume ratio of 3:1, stirring and washing at room temperature for 20 min / time to remove residual organochlorine and unreacted intermediates), followed by water washing until neutral. The residual solvent and low-boiling substances are removed under a vacuum of 0.09 MPa and at 120 °C (removal time 2 h, ensuring that the residual epichlorohydrin content is ≤50 ppm). Then, it is treated with cation exchange resin (resin dosage is 5% of the organic phase mass, flow rate 2 BV / h, adsorption temperature 40 °C) to obtain high-purity electronic-grade bisphenol F type epoxy resin.

[0053] Test results: epoxy value 0.53eq / 100g, total chlorine content 390ppm, viscosity at 25℃ 1900mPa.s, Tg 130℃, water absorption rate 0.1%.

[0054] Example 2: Step I: Select a pore diameter of 10 nm and a specific surface area of ​​700 m² 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0055] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 90g of anhydrous toluene, add 2.5g of mercaptohexyltriethoxysilane, and reflux at 85℃ for 14h under nitrogen protection. After the reaction is complete, filter, wash the filter cake four times with anhydrous toluene, and dry it under vacuum at 80℃ for 6h to obtain mercapto-modified SBA-15. The mercapto grafting density was measured to be 1.0 mmol / g.

[0056] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 70g of anhydrous ethanol, adjust the pH of the reaction system to 6.5, add 3-triethoxysilylpropyltrimethylammonium chloride, with a quaternary ammonium salt to mercapto graft molar ratio of 1:2, and stir at 45℃ for 9h. After filtration, wash four times with anhydrous ethanol, and dry under vacuum at 100℃ for 7h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.5mmol / g.

[0057] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 80g of anhydrous dichloromethane, add 3-propanesulfonic acid triethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:1.0, and react under nitrogen protection at 55℃ with stirring for 7h. After filtration, wash four times with anhydrous dichloromethane, and dry under vacuum at 85℃ for 5h to obtain triple-modified mesoporous SBA-15. The sulfonic acid group grafting density is 1.00mmol / g.

[0058] Step V: Add 100g phenol, 10g of modified mesoporous SBA-15, and 175g toluene to the reactor. Stir and disperse until the system temperature drops to 30℃. Add 28g of 37% formaldehyde solution dropwise and react at a constant temperature for 2.5h. After the reaction, filter to recover the catalyst. Place the filtrate at 0℃ for freeze crystallization for 14h. Filter, wash, and dry to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 88%, the total chlorine content is 80ppm, and the total metal ion content is 3ppm.

[0059] Etherification reaction: high-purity bisphenol F to epichlorohydrin molar ratio 1:8, catalyst dosage 1.0%, reaction at 75℃ for 5h; Cyclization reaction: vacuum degree 0.085MPa, 85℃, NaOH to bisphenol F molar ratio 1.03:1, dropping rate 0.75mL / min, 1.25mL / min, 0.75mL / min, heat preservation for 1.25h; post-treatment is the same as in Example 1 (static layering, alkali washing, water washing, vacuum desolventizing and cation exchange resin treatment key parameters are consistent).

[0060] Test results: epoxy value 0.55eq / 100g, total chlorine content 320ppm, viscosity at 25℃ 1600mPa.s, Tg 135℃, water absorption rate 0.08%.

[0061] Example 3: Step I: Select a pore diameter of 11 nm and a specific surface area of ​​800 m². 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0062] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 100g of anhydrous toluene, add 3.3g of mercaptohexyltriethoxysilane, and reflux at 90℃ for 16h under nitrogen protection. After the reaction is complete, filter, wash the filter cake 5 times with anhydrous toluene, and dry it under vacuum at 90℃ for 6h to obtain mercapto-modified SBA-15. The mercapto grafting density was measured to be 1.2mmol / g.

[0063] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 80g of anhydrous ethanol, adjust the pH of the reaction system to 7, add 3-triethoxysilylpropyltrimethylammonium chloride, with a quaternary ammonium salt to mercapto graft molar ratio of 1:1.8, and stir the reaction at 50℃ for 10h. Filter, wash 4 times with ethanol, and vacuum dry at 110℃ for 8h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.67mmol / g.

[0064] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 90g of anhydrous dichloromethane, add 3-propanesulfonic acid triethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:0.8, and react under nitrogen protection at 60℃ with stirring for 8h. Filter, wash 5 times with anhydrous dichloromethane, and dry under vacuum at 90℃ for 6h to obtain triple-modified mesoporous SBA-15. The sulfonic acid group grafting density is 1.50mmol / g.

[0065] Step V: Add 100g phenol, 12g of modified mesoporous SBA-15, and 200g toluene to the reactor. Stir and disperse until the system temperature drops to 35℃. Add 30g of 37% formaldehyde solution dropwise and react at a constant temperature for 3h. After the reaction, filter to recover the catalyst. Place the filtrate at -2℃ for freeze crystallization for 16h. Filter, wash, and dry to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 86%, the total chlorine content is 90ppm, and the total metal ion content is 4ppm.

[0066] Etherification reaction: high-purity bisphenol F to epichlorohydrin molar ratio 1:10, catalyst dosage 1.2%, reaction at 80℃ for 6h; Cyclization reaction: vacuum degree 0.09MPa, 90℃, NaOH to bisphenol F molar ratio 1.05:1, dropping rate 1mL / min, 1.5mL / min, 1mL / min, heat preservation for 1.5h; post-treatment is the same as in Example 1 (static layering, alkali washing, water washing, vacuum desolventizing and cation exchange resin treatment key parameters are the same).

[0067] Test results: epoxy value 0.54eq / 100g, total chlorine content 350ppm, viscosity at 25℃ 1800mPa.s, Tg 132℃, water absorption rate 0.09%.

[0068] Example 4: Step I: Select a pore diameter of 10 nm and a specific surface area of ​​700 m². 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0069] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 90g of anhydrous toluene, add 2.5g of mercaptooctyltriethoxysilane, and reflux at 85℃ for 14h under nitrogen protection. After the reaction is complete, filter, wash the filter cake four times with anhydrous toluene, and dry it under vacuum at 80℃ for 6h to obtain mercapto-modified SBA-15. The mercapto grafting density was measured to be 1.0 mmol / g.

[0070] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 70g of anhydrous ethanol, adjust the pH of the reaction system to 6.5, add 3-triethoxysilylpropyltrimethylammonium chloride, with a quaternary ammonium salt to mercapto graft molar ratio of 1:2, and stir at 45℃ for 9h. After filtration, wash four times with anhydrous ethanol, and dry under vacuum at 100℃ for 7h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.5mmol / g.

[0071] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 80g of anhydrous dichloromethane, add 4-sulfonobutyltriethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:1.0, and stir at 55℃ for 7h under nitrogen protection. After filtration, wash four times with anhydrous dichloromethane, and dry under vacuum at 85℃ for 5h to obtain triple-modified mesoporous SBA-15. The sulfonic acid group grafting density is 1.00mmol / g.

[0072] Step V: Add 100g phenol, 10g of modified mesoporous SBA-15, and 175g toluene to the reactor. Stir and disperse until the system temperature drops to 30℃. Add 28g of 37% formaldehyde solution dropwise and react at a constant temperature for 2.5h. After the reaction, filter to recover the catalyst. Place the filtrate at 0℃ for freeze crystallization for 14h. Filter, wash, and dry to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 88%, the total chlorine content is 80ppm, and the total metal ion content is 3ppm.

[0073] Etherification reaction: high-purity bisphenol F to epichlorohydrin molar ratio 1:8, catalyst dosage 1.0%, reaction at 75℃ for 5h; Cyclization reaction: vacuum degree 0.085MPa, 85℃, NaOH to bisphenol F molar ratio 1.03:1, dropping rate 0.75mL / min, 1.25mL / min, 0.75mL / min, heat preservation for 1.25h; post-treatment is the same as in Example 1 (static layering, alkali washing, water washing, vacuum desolventizing and cation exchange resin treatment key parameters are consistent).

[0074] Test results: epoxy value 0.54eq / 100g, total chlorine content 370ppm, viscosity at 25℃ 1700mPa.s, Tg 133℃, water absorption rate 0.1%.

[0075] Example 5: Step I: Select a pore diameter of 10 nm and a specific surface area of ​​700 m². 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0076] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 90g of anhydrous toluene, add 2.5g of mercaptohexyltriethoxysilane, and reflux at 85℃ for 14h under nitrogen protection. After the reaction is complete, filter, wash the filter cake four times with anhydrous toluene, and dry it under vacuum at 80℃ for 6h to obtain mercapto-modified SBA-15. The mercapto grafting density was measured to be 1.0 mmol / g.

[0077] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 70g of anhydrous ethanol, adjust the pH of the reaction system to 6.5, add 3-triethoxysilylpropyltrimethylammonium chloride, with a quaternary ammonium salt to mercapto graft molar ratio of 1:2, and stir at 45℃ for 9h. After filtration, wash four times with anhydrous ethanol, and dry under vacuum at 100℃ for 7h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.5mmol / g.

[0078] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 80g of anhydrous dichloromethane, add 3-propanesulfonic acid triethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:1.0, and stir at 55℃ for 7h under nitrogen protection. After filtration, wash 4 times with anhydrous dichloromethane, and dry under vacuum at 85℃ for 5h to obtain triple-modified mesoporous SBA-15.

[0079] Step V: Add 100g phenol, 10g of modified mesoporous SBA-15, and 175g toluene to the reactor. Stir and disperse until the system temperature drops to 30℃. Add 28g of 37% formaldehyde solution dropwise and react at a constant temperature for 2.5h. After the reaction, filter to recover the catalyst. Place the filtrate at 0℃ for freeze crystallization for 14h. Filter, wash, and dry to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 88%, the total chlorine content is 80ppm, and the total metal ion content is 3ppm.

[0080] Etherification reaction: high-purity bisphenol F to epichlorohydrin molar ratio 1:5, catalyst dosage 1.5%, reaction at 75℃ for 5h; Cyclization reaction: vacuum degree 0.085MPa, 85℃, NaOH to bisphenol F molar ratio 1.03:1, dropping rate 0.75mL / min, 1.25mL / min, 0.75mL / min, heat preservation for 1.25h; post-treatment is the same as in Example 1 (static layering, alkali washing, water washing, vacuum desolventizing and cation exchange resin treatment key parameters are the same).

[0081] Test results: epoxy value 0.53eq / 100g, total chlorine content 400ppm, viscosity at 25℃ 1980mPa·s, Tg 130℃, water absorption rate 0.09%.

[0082] Example 6: Step I: Select a pore diameter of 10 nm and a specific surface area of ​​700 m² 2 / g of mesoporous SBA-15 was vacuum dried at 110℃ for 8h to remove surface adsorbed water and then set aside for use.

[0083] Step II: Take 10g of the above mesoporous SBA-15, disperse it in 90g of anhydrous toluene, add 2.5g of mercaptohexyltriethoxysilane, and reflux at 85℃ for 14h under nitrogen protection. After the reaction is complete, filter, wash the filter cake four times with anhydrous toluene, and dry it under vacuum at 80℃ for 6h to obtain mercapto-modified SBA-15. The mercapto grafting density was measured to be 1.0 mmol / g.

[0084] Step III: Take 10g of single-modified mesoporous SBA-15, disperse it in 70g of anhydrous ethanol, adjust the pH of the reaction system to 6.5, add 3-triethoxysilylpropyltrimethylammonium chloride, with a quaternary ammonium salt to mercapto graft molar ratio of 1:2, and stir at 45℃ for 9h. After filtration, wash four times with anhydrous ethanol, and dry under vacuum at 100℃ for 7h to obtain double-modified mesoporous SBA-15 with a quaternary ammonium salt grafting density of 0.5mmol / g.

[0085] Step IV: Take 10g of double-modified mesoporous SBA-15, disperse it in 80g of anhydrous dichloromethane, add 3-propanesulfonic acid triethoxysilane, with a sulfonic acid group to mercapto group grafting molar ratio of 1:1.0, and stir at 55℃ for 7h under nitrogen protection. After filtration, wash 4 times with anhydrous dichloromethane, and dry under vacuum at 85℃ for 5h to obtain triple-modified mesoporous SBA-15.

[0086] Step V: Add 100g phenol, 10g of modified mesoporous SBA-15, and 175g toluene to the reactor. Stir and disperse until the system temperature drops to 30℃. Add 28g of 37% formaldehyde solution dropwise and react at a constant temperature for 2.5h. After the reaction, filter to recover the catalyst. Place the filtrate at 0℃ for freeze crystallization for 14h. Filter, wash, and dry to obtain high-purity bisphenol F. The test results show that the 4,4'-isomer accounts for 88%, the total chlorine content is 80ppm, and the total metal ion content is 3ppm.

[0087] Etherification reaction: high-purity bisphenol F to epichlorohydrin molar ratio 1:8, catalyst dosage 1.0%, reaction at 75℃ for 5h; Cyclization reaction: vacuum degree 0.085MPa, 85℃, NaOH to bisphenol F molar ratio 1.03:1, dropping rate 1mL / min, 1mL / min, 1mL / min, heat preservation for 1.25h; post-treatment is the same as in Example 1 (static layering, alkali washing, water washing, vacuum desolventizing and cation exchange resin treatment key parameters are the same).

[0088] Test results: epoxy value 0.53eq / 100g, total chlorine content 400ppm, viscosity at 25℃ 2000mPa.s, Tg 133℃, water absorption rate 0.09%.

[0089] Comparative Example 1: Only mesoporous SBA-15 was modified with sulfonic acid groups (i.e., steps II and III were omitted), and the sulfonic acid group grafting density was 1.0 mmol / g. The remaining steps were completely consistent with those in Example 2.

[0090] Test results: Bisphenol F contained 62% 4,4'-isomers and 180 ppm total chlorine; epoxy resin contained 580 ppm total chlorine and had a Tg of 115℃, which did not meet the electronic grade requirements.

[0091] Therefore, lacking the steric shielding function of thiol groups and the complexing function of quaternary ammonium salts, the catalyst exhibits extremely poor directional selectivity, leading to increased side reactions and excessive impurity content.

[0092] Comparative Example 2: Step III (quaternary ammonium salt modification) in Example 2 was omitted, and only thiol-sulfonic acid double modification was performed. The thiol grafting density was 1.0 mmol / g, and the molar ratio of sulfonic acid to thiol was 1:1.0. The remaining steps were the same as in Example 2.

[0093] Test results: Bisphenol F contained 73% 4,4'-isomers and 120 ppm total chlorine; epoxy resin contained 480 ppm total chlorine and had a viscosity of 2300 mPa·s at 25℃, which was too high.

[0094] Therefore, it lacks the complexation function of quaternary ammonium salt with formaldehyde, formaldehyde has low solubility in toluene, the reaction system is heterogeneous, and side reactions and viscosity cannot be controlled.

[0095] Compared with Comparative Examples 1-2, Comparative Example 1 only modified mesoporous SBA-15 with a single sulfonic acid group, and Comparative Example 2 only modified mesoporous SBA-15 with a double mercapto-sulfonic acid group. The modified mesoporous SBA-15 obtained by both examples was applied to the synthesis of bisphenol F and the subsequent preparation of epoxy resin, and the product performance was far from meeting the requirements of electronic grade indicators.

[0096] It is evident that the synergistic effect of the three functional groups—thiol group, quaternary ammonium salt, and sulfonic acid group—in this application is a necessary condition for achieving high 4,4'-isomer selectivity of bisphenol F, regulating the homogeneity of the reaction system, reducing the impurity content of the product, and optimizing the overall performance of the epoxy resin. All three are indispensable, and their synergistic effect enables the preparation of highly selective and high-purity bisphenol F and electronic-grade bisphenol F type epoxy resin.

[0097] Comparative Example 3: The mercaptohexyltriethoxysilane in step II of Example 2 was replaced with mercaptopropyltriethoxysilane, and the remaining steps were the same as in Example 2.

[0098] Test results: Bisphenol F contains 70% 4,4'-isomers and 110 ppm total chlorine; epoxy resin Tg is 120℃, indicating insufficient heat resistance.

[0099] Therefore, short chains cannot form an effective spatial barrier, the 2-position shielding of phenol is insufficient, the proportion of target isomers is low, and the heat resistance of epoxy resin is affected.

[0100] Compared with Examples 2 and 4, Comparative Example 3 used mercaptopropyltriethoxysilane, while keeping all other process parameters the same. The proportion of the 4,4'-isomer of the obtained bisphenol F was significantly reduced, and the glass transition temperature of the subsequently prepared epoxy resin did not meet the electronic grade requirements.

[0101] It is evident that the mercaptohexyltriethoxysilane and mercaptooctyltriethoxysilane selected in this application are long-chain alkyl mercaptosilanes. Their long-chain structure can form an effective spatial barrier on the surface of mesoporous SBA-15, achieving precise shielding of the 2-position of phenol, thereby improving the directional selectivity of the 4,4'-isomer during the synthesis of bisphenol F, so that the proportion of the 4,4'-isomer is greater than or equal to 85%. Moreover, this spatial shielding effect can further optimize the heat resistance of the subsequent epoxy resin. In contrast, mercaptopropyltriethoxysilane is a short-chain alkyl mercaptosilane, which cannot form an effective spatial shielding structure. Side reactions easily occur at the 2-position of phenol, leading to a decrease in the proportion of the target 4,4'-isomer, ultimately resulting in insufficient heat resistance of the epoxy resin, which cannot meet the requirements of electronic-grade applications.

[0102] Comparative Example 4: Steps I-IV (preparation of three-modified catalyst) in Example 2 are omitted. In step V, hydrochloric acid is used as a homogeneous catalyst (the amount is 1.0% of the mass of phenol). The remaining steps are the same as in Example 2.

[0103] Test results: Bisphenol F contained 58% 4,4'-isomers, 350 ppm total chlorine, and 25 ppm metal ions; epoxy resin contained 820 ppm total chlorine and 18 ppm metal ions, which completely failed to meet the electronic grade requirements.

[0104] Comparative Example 4 used hydrochloric acid homogeneous catalyst to synthesize bisphenol F. The remaining process parameters were the same as in Example 2. The proportion of 4,4'-isomer in the obtained bisphenol F was significantly reduced. Moreover, the total chlorine content and metal ion content of bisphenol F and subsequent epoxy resin far exceeded the requirements of electronic grade indicators, and could not meet the electronic grade application standards at all.

[0105] As can be seen, the modified mesoporous SBA-15 of this application, as a heterogeneous catalyst, relies on the synergistic effect of the three functional groups of mercapto, quaternary ammonium salt and sulfonic acid group to achieve high directional selectivity for the synthesis of bisphenol F 4,4'-isomers. Moreover, this heterogeneous catalyst can be separated and recovered by simple filtration, without the introduction of chlorine impurities and metal ion impurities by catalyst residue, which greatly improves the purity of the product. In contrast, the hydrochloric acid homogeneous catalyst has no directional catalytic selectivity, is prone to triggering a large number of side reactions, resulting in a decrease in the proportion of the target isomer. Furthermore, the homogeneous catalyst cannot be completely separated by simple means, leaving chlorine impurities in the product system and easily introducing metal ion impurities, ultimately causing the purity indicators of bisphenol F and epoxy resin to seriously fail to meet the standards.

[0106] Comparative Example 5: The only difference was that the mesoporous SBA-15 in step I of Example 2 was replaced with a carrier with a pore diameter of 7 nm and a specific surface area of ​​650 m² / g. The remaining steps were completely the same as in Example 2.

[0107] Test results: Bisphenol F contained 72% 4,4'-isomers and 130 ppm total chlorine; epoxy resin contained 490 ppm total chlorine, with a viscosity of 2200 mPa·s at 25℃ and a Tg of 118℃. Both viscosity and heat resistance failed to meet the standards.

[0108] Conclusion: The 7nm mesopore diameter is too narrow to accommodate the space occupied by C8 long-chain alkyl mercapto groups, resulting in partial blockage of the pores, hindered reactant diffusion, uneven distribution of functional groups, failure of spatial shielding and catalytic synergy, and a significant decrease in selectivity and product performance.

[0109] Comparative Example 6: In step II, the amount of mercaptohexyltriethoxysilane was reduced to 1 g, and the mercapto grafting density was 0.5 mmol / g. The remaining steps were completely consistent with Example 2. That is, the mercapto grafting density was 0.5 mmol / g.

[0110] Test results: Bisphenol F contained 68% 4,4'-isomers and 140 ppm total chlorine; epoxy resin contained 520 ppm total chlorine and had a Tg of 116℃, which did not meet the electronic grade requirements.

[0111] Comparative Example 7: In step III, the molar ratio of quaternary ammonium salt to mercapto graft was 1:1.5, the quaternary ammonium salt grafting density was 0.67 mmol / g, and the remaining steps were completely consistent with Example 2. That is, the quaternary ammonium salt grafting density was 0.67 mmol / g.

[0112] Test results: Bisphenol F contained 74% 4,4'-isomers and 125 ppm total chlorine; epoxy resin contained 470 ppm total chlorine and had a viscosity of 2100 mPa.s at 25℃, which exceeded the viscosity standard.

[0113] Comparative Example 8: In step IV, the molar ratio of sulfonic acid groups to mercapto groups was 1:0.6, the sulfonic acid group grafting density was 1.7 mmol / g, and the remaining steps were completely consistent with Example 2. That is, the sulfonic acid group grafting density was 1.7 mmol / g.

[0114] Test results: Bisphenol F contained 70% 4,4'-isomers and 150 ppm total chlorine; epoxy resin contained 530 ppm total chlorine and had a Tg of 117℃. Both impurities and performance did not meet the standards.

[0115] Compared with Example 2, Comparative Example 6 reduced the thiol grafting density to 0.5 mmol / g, Comparative Example 7 adjusted the grafting molar ratio of quaternary ammonium salt to thiol to 1:1.5, and Comparative Example 8 adjusted the grafting molar ratio of sulfonic acid group to thiol group to 1:0.6. All other process conditions remained the same. The proportion of 4,4'-isomer in the final bisphenol F was significantly reduced. The total chlorine content, glass transition temperature, viscosity and other indicators of the epoxy resin prepared subsequently could not meet the requirements of electronic grade applications.

[0116] It is evident that the thiol grafting density of 0.8~1.2 mmol / g, the quaternary ammonium salt to thiol grafting molar ratio of 1:(1.8~2.2), and the sulfonic acid group to thiol grafting molar ratio of 1:(0.8~1.2) specified in this application are the optimal parameter ranges for achieving the synergistic effect of the three functional groups of thiol, quaternary ammonium salt, and sulfonic acid group.

[0117] The inventors hypothesize that a thiol grafting density of 0.8–1.2 mmol / g is required to form an effective spatial shielding structure. The grafting ratio of quaternary ammonium salt and sulfonic acid group must match that of thiol group to ensure the synergistic adaptation of formaldehyde complexation, catalytic active center distribution, and spatial shielding effect. If the grafting parameter of any functional group deviates from this range, it will disrupt the synergistic mechanism of the trifunctional groups, leading to a decrease in the directional selectivity of bisphenol F synthesis, an increase in side reactions, and consequently, a deterioration in the core indicators of the subsequent epoxy resin, such as purity, heat resistance, and rheological properties, making it impossible to meet the standard requirements of electronic-grade products.

[0118] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing high purity electronic grade bisphenol F type epoxy resin by tri-modified mesoporous SBA-15, characterized by, At least the following steps are included: Step I: Obtain mesoporous SBA-15 with a pore diameter of 9 nm to 11 nm and a specific surface area of ​​600 m². 2 / g to 800m 2 / g; Step II: First modification: The mesoporous SBA-15 was dispersed in anhydrous toluene, and mercaptohexyltriethoxysilane or mercaptooctyltriethoxysilane was added to react and obtain monomodified mesoporous SBA-15 with a mercapto grafting density of 0.8 mmol / g to 1.2 mmol / g. Step III: Second modification: The single-modified mesoporous SBA-15 is dispersed in anhydrous ethanol, and 3-triethoxysilylpropyltrimethylammonium chloride is added to react and obtain double-modified mesoporous SBA-15. The grafting molar ratio of quaternary ammonium salt to mercapto group is 1:(1.8~2.2). Step IV: Third modification: The double-modified mesoporous SBA-15 is dispersed in anhydrous dichloromethane, and 3-propanesulfonic acid triethoxysilane or 4-sulfonic acid butyltriethoxysilane is added to react and obtain triple-modified mesoporous SBA-15. The grafting molar ratio of sulfonic acid groups to mercapto groups is 1:(0.8~1.2). Step V: Phenol and the modified mesoporous SBA-15 were added to the reaction vessel, then toluene was added, and the mixture was stirred and dispersed until the temperature of the reaction system dropped to 25°C to 35°C. Formaldehyde solution was added dropwise, and the reaction was carried out at a constant temperature for 2 to 3 hours. The mixture was then frozen and crystallized at -5°C to 0°C for 12 to 16 hours and filtered to obtain bisphenol F. Step VI: Etherification reaction: Bisphenol F and epichlorohydrin are mixed, and benzyltriethylammonium chloride is added to react and etherification product is obtained; Step VII: Cyclization reaction: Add NaOH aqueous solution dropwise to the etherified product, wherein the molar ratio of NaOH to bisphenol F is (1.02~1.05):

1. After the addition is completed, keep the reaction at the temperature for 1 to 1.5 hours to obtain the cyclized product. Step VIII: Post-processing purification: The cyclized product is allowed to stand and separate into layers. The aqueous phase is removed, and the organic phase is subjected to two alkaline washes and water washes until neutral. The residual solvent and low-boiling substances are removed under reduced pressure. Then, the product is treated with ion exchange resin to remove metal ions, thereby obtaining high-purity electronic-grade bisphenol F type epoxy resin.

2. The method according to claim 1, characterized in that, The high-purity electronic-grade bisphenol F epoxy resin has an epoxy value greater than or equal to 0.53 eq / 100g, a total chlorine content less than or equal to 400 ppm, and a viscosity at 25°C less than or equal to 2000 mPas; and / or, The high-purity electronic-grade bisphenol F epoxy resin has a glass transition temperature ≥130℃ and a water absorption rate ≤0.1%.

3. The method according to claim 1, characterized in that, In step V, the mass ratio of phenol, the three-modified mesoporous SBA-15 and the toluene is 1:(0.08~0.12):(1.5~2.0), and the mass ratio of phenol and the formaldehyde solution is 1:(0.26~0.30).

4. The method according to claim 1, characterized in that, In step II, the reaction conditions include: reflux for 12 to 16 hours under nitrogen protection at an ambient temperature of 80°C to 90°C, followed by filtration, washing with toluene 3 to 5 times, and vacuum drying after the reaction is completed.

5. The method according to claim 1, characterized in that, In step III, the reaction conditions include: constant temperature stirring reaction at an ambient temperature of 40°C to 50°C for 8 to 10 hours, filtration, washing with ethanol 3 to 5 times, and vacuum drying at 100°C to 110°C for 6 to 8 hours.

6. The method according to claim 1, characterized in that, In step IV, the reaction conditions include: under nitrogen protection, constant temperature stirring at 50°C to 60°C for 6 to 8 hours, filtration, washing with dichloromethane 3 to 5 times, and vacuum drying at 80°C to 90°C for 4 to 6 hours.

7. The method according to claim 1, characterized in that, In step VI, the molar ratio of bisphenol F to epichlorohydrin is 1:(6~10), and the benzyltriethylammonium chloride is 0.8% to 1.2% of the mass of bisphenol F. The reaction conditions include: under nitrogen protection, at an ambient temperature of 70°C to 80°C, for 4 to 6 hours.

8. The method according to claim 1, characterized in that, In step VII, a 40% (w / w) NaOH aqueous solution is added dropwise in three stages under a vacuum of 0.08 MPa to 0.09 MPa, and the temperature of the heat-preserving reaction is 80°C to 90°C; and / or, The volume ratio of the NaOH aqueous solution added in three stages is 1:2:

1. The dropping rate is 0.5 mL / min to 1 mL / min in the first stage, 1 mL / min to 1.5 mL / min in the second stage, and 0.5 mL / min to 1 mL / min in the third stage.

9. The method according to claim 1, characterized in that, In step II, the amount of anhydrous toluene used is 8 to 10 times the mass of the mesoporous SBA-15; and / or, In step III, the amount of anhydrous ethanol used is 6 to 8 times the mass of the monomodified mesoporous SBA-15; and / or, In step IV, the amount of anhydrous dichloromethane used is 7 to 9 times the mass of the double-modified mesoporous SBA-15.