A method for separating and purifying bisphenol a diglycidyl ether

Abstract

The application discloses a separation and purification method of bisphenol A diglycidyl ether. The method comprises the following steps: sequentially performing impurity removal and distillation separation on base liquid epoxy resin to obtain pure low-chlorine epoxy resin; mixing the pure low-chlorine epoxy resin with an organic solvent and an alkali solution to perform a refining reaction; sequentially performing washing and extraction separation on the refining reaction liquid; and performing desolventizing treatment on the organic phase obtained through the extraction separation to obtain bisphenol A diglycidyl ether. The product obtained through the method has high purity and good performance, the total chlorine and hydrolyzable chlorine are low, the epoxy value is high, the viscosity is low, the added value is high, and the product can be used for third-generation semiconductor packaging materials; the method has simple process, low cost and is suitable for industrialized production.

Description

Technical Field

[0001] This invention relates to a method for separating and purifying epoxy resins, specifically a method for separating and purifying bisphenol A diglycidyl ether, belonging to the field of epoxy resin material preparation. Background Technology

[0002] Bisphenol A diglycidyl ether is readily available, low in cost, produced in large quantities, and widely used. Its average degree of polymerization (n) is generally between 0 and 1. However, in actual production, due to abnormal addition reactions or incomplete ring closure, a small amount of heterogeneous end groups remain in the product. The presence of heterogeneous end groups in bisphenol A diglycidyl ether has a significant impact on downstream customer use and its performance: the presence of heterogeneous end groups increases the epoxy equivalent, leading to a decrease in the crosslinking density of the cured resin; the residual heterogeneous end groups in the cured product reduce its electrical properties and corrosion resistance.

[0003] As the use of bisphenol A type epoxy resin in high-end fields such as electronic packaging gradually increases, the performance requirements for it are also constantly improving. Compared with ordinary epoxy resin, ultra-high purity bisphenol A diglycidyl ether has the characteristics of extremely low viscosity and transparent colorless, which can be used in occasions with strict color requirements and can improve high temperature resistance.

[0004] Patent CN201210287495.1 discloses a method for purifying epoxy resin using molecular distillation technology. The method mainly uses two-stage molecular distillation technology to separate the light components and heavy components in the epoxy resin, remove heterogeneous end groups, and reduce the total chlorine from 1500ppm to below 800ppm. However, this technology has extremely stringent requirements for system vacuum, requiring the system vacuum to be less than 2Pa, but the total chlorine of the obtained product is still relatively high.

[0005] Patent CN201811048255.X discloses a new process for synthesizing high-purity bisphenol A type liquid epoxy resin. However, the molar ratio of raw material epichlorohydrin to bisphenol A is too high, the preparation process is complicated, and the reaction time is long, resulting in a high total chlorine content and a high epoxy equivalent in the obtained epoxy resin.

[0006] In summary, the existing bisphenol A diglycidyl ether is purified using only physical methods, which is relatively simple, but the total chlorine content of the product is relatively high. The chemical synthesis method is complex and cumbersome, and has disadvantages such as excessive use of epichlorohydrin, increased byproducts, and increased energy consumption.

[0007] Therefore, there is a need to develop a new separation and purification technology for bisphenol A diglycidyl ether that is simple to operate, produces high-performance products, has high processing efficiency, and is environmentally friendly and pollution-free. Summary of the Invention

[0008] To address the shortcomings of existing technologies, such as poor product performance, complex separation methods, and high costs, the present invention aims to provide a method for the separation and purification of bisphenol A diglycidyl ether. The product obtained by this method exhibits excellent performance, high purity, total chlorine ≤500ppm, epoxy equivalent of 170–172 g / eq, and viscosity ≤5000 CP (25℃). Furthermore, the purification method is simple, has a short process flow, low cost, does not generate secondary pollution, and is environmentally friendly.

[0009] To achieve the above-mentioned technical objectives, the present invention provides a method for separating and purifying bisphenol A diglycidyl ether. The method involves sequentially extracting and distilling a basic liquid epoxy resin to obtain a pure low-chlorine epoxy resin, then mixing the pure low-chlorine epoxy resin with an organic solvent and an alkaline solution for a purification reaction. The purified reaction solution is then sequentially washed and extracted. The organic phase obtained from the extraction and separation is then desolventized to obtain bisphenol A diglycidyl ether.

[0010] This invention first pre-treats a basic liquid epoxy resin by extraction to remove impurities, obtaining a low-chlorinated epoxy resin with a total chlorine content of 800–1000 ppm and a purity of 90–95%. Then, a distillation process is used to remove low-boiling-point substances and heterogeneous end groups from the resin, resulting in a high-purity low-chlorinated epoxy resin with a total chlorine content reduced to 500–700 ppm and a purity of 95–99%. Finally, during the refining process, a suitable solvent and alkaline solution are used to induce a ring-closing reaction in the small amount of hydrolyzable chlorine contained in the high-purity epoxy resin, thereby removing the hydrolyzable chlorine and reducing the chlorine content. This yields high-quality bisphenol A diglycidyl ether with a total chlorine content ≤500 ppm, hydrolyzable chlorine content ≤100 ppm, epoxy equivalent of 170–172 g / eq, viscosity ≤5000 CP (25℃), and purity ≥99%.

[0011] In this separation and purification process, the extraction and impurity removal pretreatment process can be used to separate the epoxy resin components based on their different molecular polarities. The "n>0" component in the basic liquid epoxy resin contains hydroxyl groups and has high solubility in polar solvents. Therefore, it can be separated by solvent extraction to separate the "n=0" (bisphenol A diglycidyl ether) and "n>0" components in the epoxy resin.

[0012] As a preferred embodiment, the total chlorine content of the base liquid epoxy resin does not exceed 1200 ppm. Controlling the total chlorine content of the base liquid resin within a reasonable range is beneficial to improving the separation and purification efficiency of bisphenol A diglycidyl ether. The lower the total chlorine content of the base liquid resin, the lower the total chlorine content of the resin obtained after extraction and impurity removal. If the total chlorine content of the base liquid resin is higher than 1200 ppm, it will affect the efficiency of the extraction and impurity removal pretreatment to some extent, increase the extraction and impurity removal time, and affect subsequent processing.

[0013] As a preferred embodiment, the extraction and impurity removal uses at least one of cyclohexane, toluene, methyl isobutyl ketone, butanone, and methanol as the extractant.

[0014] As a preferred embodiment, the mass ratio of the extractant to the base liquid epoxy resin in the extraction and impurity removal process is 1 to 4:1.

[0015] As a preferred embodiment, the distillation separation employs molecular distillation. Molecular distillation achieves higher separation efficiency because it utilizes the difference in the mean free path of molecular motion to separate substances. At the center of the main evaporator is a built-in hydrazine cooler. During the material scraping process, the "n=0" component in the epoxy resin begins to vaporize, moves to the hydrazine cooler, and condenses into a colorless and transparent liquid.

[0016] As a preferred embodiment, during the molecular distillation process, the temperature difference between the main evaporator and the hydrazine is controlled to be ≥140℃. During molecular distillation, a suitable temperature difference between the main evaporator and the hydrazine is beneficial for improving the separation efficiency of the epoxy resin. When the temperature difference is <140℃, it is not conducive to the rapid condensation of the "n=0" component (bisphenol A diglycidyl ether).

[0017] As a preferred embodiment, during the molecular distillation process, the preheating temperature of the jacketed feeding tank is controlled at 50-100℃, the low-chlorinated epoxy resin enters the scraped film evaporator at a flow rate of 80-150mL / min, the system pressure is ≤10Pa, and the temperature of the main evaporator is 150-200℃.

[0018] As a preferred embodiment, the organic solvent includes at least one of toluene, xylene, methyl isobutyl ketone, and ethyl acetate.

[0019] As a preferred embodiment, the mass ratio of the organic solvent to the pure low-chlorinated epoxy resin is 1–4:1. Controlling the mass ratio of high-purity epoxy resin to solvent B within a reasonable range during the purification reaction is beneficial for improving separation purity and efficiency. When the amount of organic solvent is too small, the epoxy resin is not completely dissolved, resulting in a higher system viscosity, which is detrimental to the ring-closing reaction. Conversely, when the amount of organic solvent is too large, the system viscosity is low, and the collision rate between the alkali in the aqueous phase and the hydrolyzable chlorine in the organic phase decreases, leading to residual phenolic hydroxyl products in the resin product and a decline in product performance.

[0020] As a preferred embodiment, the alkaline solution comprises sodium hydroxide solution and / or potassium hydroxide solution.

[0021] As a preferred embodiment, the mass concentration of the alkaline solution is 15% to 50%. Controlling the concentration of the alkaline solution within a suitable range can improve the purification efficiency and product performance of bisphenol A diglycidyl ether. When the alkaline solution concentration is too high, it may cause the epoxy groups of the epoxy resin itself to open, resulting in an increase in epoxy equivalent, which is not conducive to the ring-closing reaction.

[0022] As a preferred embodiment, the amount of alkali used in the alkaline solution is 0.8wt% to 2.7wt% of the pure low-chlorine epoxy resin. Controlling the amount of alkali used during the purification reaction within a reasonable range is beneficial to improving the removal efficiency of hydrolyzable chlorine. When the amount of alkali used is too low, the purification reaction is incomplete, and unclosed ring substances still exist in the system, resulting in a relative decrease in the removal efficiency of hydrolyzable chlorine. Conversely, when the amount of alkali used is too high, it not only leads to an increase in the waste polymers generated by the reaction, but also requires a large amount of pure water to wash to neutrality after the excessive alkali solution is added, resulting in an increase in the discharge of epoxy resin wastewater.

[0023] As a preferred embodiment, the purification reaction conditions are: temperature 70–90°C and time 1–2 hours. Controlling the reaction temperature and time within a reasonable range helps improve the purification efficiency and product performance of bisphenol A diglycidyl ether. Too low a reaction temperature or too short a reaction time will reduce reaction efficiency and affect the ring-closing effect; while too high a reaction temperature or too long a reaction time can easily generate alcohol hydroxyl addition products, affecting the quality of the epoxy resin.

[0024] As a preferred embodiment, the purified reaction solution is washed with water until the pH is neutral, and then extracted and separated.

[0025] As a preferred embodiment, the extraction separation uses at least one of cyclohexane, butanone, methanol, isopropanol, and tetrahydrofuran as the extractant.

[0026] As a preferred embodiment, the amount of extractant used in the extraction and separation process is 1 to 2 times the mass of the water-washed product. When the amount of extractant used is too small, the extraction layering is not obvious and the yield is low; when the amount of extractant used is too large, the time for desolventizing the obtained organic phase under reduced pressure is long, resulting in serious solvent loss and affecting the quality of solvent reuse.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The purified bisphenol A diglycidyl ether product has excellent performance, with total chlorine ≤500ppm, hydrolyzable chlorine ≤100ppm, epoxy equivalent of 170~172g / eq, viscosity ≤5000CP (25℃), and purity ≥99%.

[0029] (2) The basic liquid resin is pretreated by extraction to remove impurities before distillation separation, which significantly reduces the "n>0" macromolecular impurities in the epoxy resin entering the distillation process, improves the distillation separation efficiency, and significantly improves the product purity and yield. In particular, when the molecular distillation process is used, the separation temperature required by the scraped film evaporator is significantly reduced, which greatly reduces the purification energy consumption.

[0030] (3) The complete process of extraction and impurity removal pretreatment-distillation separation-closed-loop reaction purification treatment is adopted to gradually separate and remove impurities in epoxy resin, which greatly improves the purity and performance of bisphenol A diglycidyl ether product. Among them, after the high-purity epoxy resin obtained by distillation separation is purified, the product obtained has lower hydrolyzable chlorine content and higher purity. Moreover, the process is simple, continuous and easy to operate, and the operating parameters are stable.

[0031] (4) The components obtained by extraction and distillation separation during the separation and purification process, which are “n>0”, can be recycled and applied to fields such as glass fiber impregnating agents. This will not cause secondary pollution and will achieve efficient utilization of resources while being environmentally friendly. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating the separation and purification process of bisphenol A diglycidyl ether in Example 1 of the present invention. Detailed Implementation

[0033] The present invention is illustrated by the following embodiments, which do not constitute a limitation on the scope or implementation of the present invention.

[0034] The basic liquid epoxy resin in this invention was prepared in accordance with patent CN200510032321.0.

[0035] In the following examples, the number-average molecular weight and molecular weight distribution of the polymers were determined using a Shimadzu LC-20AD liquid gel permeation chromatograph (GPC). The epoxy equivalent was determined using the hydrochloric acid-dioxane method; the total chlorine content was determined using a Bruker SPECTROCUBE polarization energy dispersive X-ray fluorescence spectrometer (ED-XRF); the hydrolyzable chlorine content was determined using a potassium hydroxide-ethanol solution-potentiometric titration method; and the epoxy resin viscosity was measured using a rotational viscometer. All indicators were determined according to the Q / SH 1085 007-2020 standard.

[0036] Example 1

[0037] 1000g of basic liquid epoxy resin was weighed, with a total chlorine content of 1120ppm and a purity of 85.27%. 2000g of cyclohexane was added, stirred thoroughly, and placed in a separatory funnel. After standing for 2 hours, distinct layers were observed. Organic phase I was collected and desolventized under negative pressure to obtain 450g of low-chlorinated epoxy resin with a total chlorine content of 880ppm and a purity of 91.27%. The molecular distillation jacket feed tank was preheated to 65℃. The low-chlorinated epoxy resin was fed into a scraped-film evaporator at a flow rate of 100mL / min. The vacuum in the system was maintained at 8Pa, the main evaporator temperature was controlled at 180℃, and the main evaporator cooling temperature was 30℃. 135g of high-purity epoxy resin was obtained, with a total chlorine content of 625ppm, hydrolyzable chlorine content of 218ppm, a purity of 97.30%, and a yield of 30%. 270g of ethyl acetate was mixed with high-purity epoxy resin, and the temperature of the mixture was controlled at 85℃. Then, 3.38g of 15% sodium hydroxide solution was added dropwise for purification. After 1.5h of purification reaction, pure water was added to the product, and the product was washed with water until the pH was neutral. Then, 1.5 times the mass of the washed product was extracted with butanone. The organic phase II was taken and desolventized under reduced pressure to obtain bisphenol A diglycidyl ether.

[0038] Product specifications analysis: Total chlorine is 485 ppm, hydrolyzable chlorine is 86 ppm, epoxy equivalent is 171.25 g / eq, viscosity is 4920 CP, and purity is 99.25%.

[0039] Example 2

[0040] 1000g of basic liquid epoxy resin was weighed, with a total chlorine content of 1120ppm and a purity of 85.27%. 2000g of cyclohexane was added, stirred thoroughly, and placed in a separatory funnel. After standing for 2 hours, distinct layers were observed. Organic phase I was collected and desolventized under negative pressure to obtain 450g of low-chlorinated epoxy resin with a total chlorine content of 880ppm and a purity of 91.27%. The molecular distillation jacket feed tank was preheated to 65℃. The low-chlorinated epoxy resin was fed into a scraped-film evaporator at a flow rate of 100mL / min. The vacuum in the molecular distillation system was maintained at 3Pa, the main evaporator temperature was controlled at 178℃, and the main evaporator cooling temperature was 25℃. 144g of high-purity epoxy resin was obtained, with a total chlorine content of 600ppm, hydrolyzable chlorine content of 205ppm, a purity of 97.85%, and a yield of 32%. 288g of ethyl acetate was added to high-purity epoxy resin, and the temperature of the mixture was controlled at 85℃. Then, 3.60g of 15% sodium hydroxide solution was added dropwise for purification reaction. After purification reaction for 1.5h, pure water was added to the product, and the product was washed with water until the pH was neutral. Then, 1.5 times the mass of the washed product was extracted with butanone. The organic phase II was taken and desolventized under reduced pressure to obtain bisphenol A diglycidyl ether.

[0041] Product specifications analysis: Total chlorine is 475 ppm, hydrolyzable chlorine is 85 ppm, epoxy equivalent is 171.00 g / eq, viscosity is 4870 CP, and purity is 99.45%.

[0042] Example 3

[0043] 1000g of basic liquid epoxy resin was weighed, with a total chlorine content of 1120ppm and a purity of 85.27%. 2000g of cyclohexane was added, stirred thoroughly, and placed in a separatory funnel. After standing for 2 hours, distinct layers were observed. Organic phase I was collected and desolventized under negative pressure to obtain 450g of low-chlorinated epoxy resin with a total chlorine content of 880ppm and a purity of 91.27%. The molecular distillation jacket feed tank was preheated to 65℃. The low-chlorinated epoxy resin was fed into a scraped-film evaporator at a flow rate of 100mL / min. The vacuum in the system was maintained at 8Pa, the main evaporator temperature was controlled at 180℃, and the main evaporator cooling temperature was 30℃. 135g of high-purity epoxy resin was obtained, with a total chlorine content of 625ppm, hydrolyzable chlorine content of 218ppm, a purity of 97.30%, and a yield of 30%. Add 405g of ethyl acetate to high-purity epoxy resin, control the temperature of the mixture at 88℃, and then add 2.54g of 20% potassium hydroxide solution for purification reaction. After purification reaction for 2.0h, add pure water to the product and wash the product with water until the pH is neutral. Then add 1.5 times the mass of the washed product with butanone for extraction. Take organic phase II and desolventize under reduced pressure to obtain bisphenol A diglycidyl ether.

[0044] Product specifications analysis: Total chlorine is 480 ppm, hydrolyzable chlorine is 85 ppm, epoxy equivalent is 171.15 g / eq, viscosity is 4890 CP, and purity is 99.30%.

[0045] Comparative Example 1

[0046] The method of Example 1 was used to separate and purify bisphenol A diglycidyl ether, with the difference being that: instead of solvent A extraction process, the basic liquid epoxy resin was directly subjected to molecular distillation to obtain a high-purity epoxy resin with a total chlorine content of 650 ppm, a hydrolyzable chlorine content of 225 ppm, a purity of 96.50%, and a yield of 15%.

[0047] Analysis of the product indicators of bisphenol A diglycidyl ether obtained under the preparation conditions: total chlorine 515 ppm, hydrolyzable chlorine 125 ppm, epoxy equivalent 173.25 g / eq, viscosity 5520 CP, and purity 98.25%.

[0048] Comparative Example 2

[0049] Bisphenol A diglycidyl ether was separated and purified using the method of Example 1, with the following differences: the total chlorine content of the base liquid epoxy resin was controlled at 1550 ppm, with a purity of 82.25%. Specifically, the low-chlorine epoxy resin obtained after cyclohexane extraction had a total chlorine content of 1280 ppm and a purity of 84.27%; the high-purity epoxy resin obtained after molecular distillation had a total chlorine content of 695 ppm, with 275 ppm of hydrolyzable chlorine, a purity of 96.00%, and a yield of 18%.

[0050] Analysis of the product indicators of bisphenol A diglycidyl ether obtained under the preparation conditions: total chlorine 560 ppm, hydrolyzable chlorine 175 ppm, epoxy equivalent 175.25 g / eq, viscosity 5820 CP, and purity 97.85%.

[0051] Comparative Example 3

[0052] Bisphenol A diglycidyl ether was separated and purified using the method described in Example 1, except that the sodium hydroxide solution was converted into solid sodium hydroxide during the purification reaction.

[0053] The bisphenol A diglycidyl ether product obtained under the preparation conditions has the following specifications: total chlorine content of 610 ppm, hydrolyzable chlorine content of 208 ppm, epoxy equivalent of 176.65 g / eq, viscosity of 5900 CP, and purity of 97.85%.

[0054] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A method for separating and purifying bisphenol A diglycidyl ether, characterized in that: The base liquid epoxy resin was sequentially extracted with cyclohexane and separated by molecular distillation to obtain pure low-chlorine epoxy resin. The pure low-chlorine epoxy resin was then mixed with an organic solvent and an alkaline solution for purification. The purified reaction solution was sequentially washed and extracted. The organic phase obtained by extraction and separation was desolventized to obtain bisphenol A diglycidyl ether. The total chlorine content of the base liquid epoxy resin shall not exceed 1200 ppm; The mass ratio of cyclohexane to the base liquid epoxy resin is 1~4:1; During the molecular distillation process, the temperature difference between the main evaporator and the cold hydrazine is controlled to be ≥140℃. The mass ratio of the organic solvent to the pure low-chlorine epoxy resin is 1~4:1; The amount of alkali used in the alkaline solution is 0.8wt% to 2.7wt% of pure low-chlorinated epoxy resin; the alkaline solution includes sodium hydroxide solution and / or potassium hydroxide solution; the mass concentration of the alkaline solution is 15% to 50%.

2. The method for separating and purifying bisphenol A diglycidyl ether according to claim 1, characterized in that: The organic solvent includes at least one of toluene, xylene, methyl isobutyl ketone, and ethyl acetate.

3. The method for separating and purifying bisphenol A diglycidyl ether according to claim 1, characterized in that: The conditions for the purification reaction are: temperature 70~90℃, time 1~2h.

4. The method for separating and purifying bisphenol A diglycidyl ether according to claim 1, characterized in that: The extraction and separation process uses at least one of butanone, methanol, isopropanol, and tetrahydrofuran as the extractant.

5. The method for separating and purifying bisphenol A diglycidyl ether according to claim 1 or 4, characterized in that: The purified reaction solution is washed with water until the pH is neutral, and then extracted and separated.

Images