Method for improving quality of bisphenol A product

Abstract

The invention provides a method for improving the quality of a bisphenol A product, which comprises the following steps: adding a resin adsorption bed to adsorb BPA mother liquor before the BPA mother liquor is recycled to a BPA reactor, and performing functional modification on the resin adsorption bed by using matrix resin to obtain modified resin; the matrix resin is activated by using a sulfuric acid aqueous solution, so that further modification on the matrix resin is facilitated; the quaternary ammonium group is added on the resin, so that the resin can adsorb sulfonic acid groups such as p-hydroxybenzenesulfonic acid and p-sulfobenzoic acid in the BPA mother liquor; a long-chain alkyl group with a hydrophobic property is grafted on resin, polyphenol impurities in a system are captured through a hydrophobic effect and a pi-pi stacking effect, and transition metal ions are adsorbed through impregnation, so that the transition metal ions and the polyphenol impurities can form a stable chelate; the selective adsorption capacity of the modified resin on polyphenol impurities in a system is improved, so that the purification of the BPA mother liquor is realized, and the purpose of improving the quality of a bisphenol A product is achieved.

Description

Technical Field

[0001] This invention belongs to the field of resin adsorption and application, and specifically relates to a method for improving the quality of bisphenol A products. Background Technology

[0002] 2,2-Bis(4'-hydroxyphenyl)propane, also known as bisphenol A (BPA), is an important organic chemical raw material with a wide range of applications. It can be used to produce various polymer materials such as polycarbonate (the polycarbonate (PC) plastic used in baby bottles), epoxy resin (commonly used for the inner coating of some food and beverage cans), polyester resin, polysulfone resin, polyphenylene ether resin, and unsaturated polyester resin. It can also be used to produce fine chemical products such as polyvinyl chloride stabilizers, plasticizers, flame retardants, plastic antioxidants, heat stabilizers, rubber antioxidants, ultraviolet absorbers, agricultural fungicides, pesticides, and coatings.

[0003] Currently, the industrial production of bisphenol A (BPA) generally uses an excess of phenol to react with acetone. To save production costs, the remaining phenol in the reaction system is recycled. The current actual BPA production process is as follows: excess phenol reacts with acetone, BPA crystallizes and separates, yielding crude BPA and a mother liquor containing phenol and impurities. The crude BPA is then purified and granulated to obtain BPA, and the mother liquor is reused in the previous reaction process. However, during this mother liquor reuse process, some of the heavy polymer impurities generated in the reaction, as well as a small amount of acid radicals detached due to increased catalyst usage time, gradually accumulate in the entire BPA production system, ultimately leading to a decline in BPA product quality.

[0004] To address the aforementioned issues, patent CN116410060B provides a method for suppressing the formation of isopropenylphenol (IPP) impurities during the synthesis of bisphenol A. This method suppresses IPP formation by adjusting the content of 2,4'-BPA in the mother liquor to the mass ratio of phenol to acetone, thereby improving the selectivity of phenol raw materials and preventing IPP impurities from being carried into the bisphenol A product. However, this method requires the addition of fresh phenol to control the 2,4'-BPA content in the mother liquor, and industrial applications require real-time control of the phenol addition amount. The method is complex and increases BPA production costs, hindering large-scale industrial application.

[0005] Patent CN116874355B reports a method for reducing the color of phenol / bisphenol A products. This method mainly involves multiple operations such as solvent dissolution, chemical reaction, static separation, and physical adsorption to ultimately remove impurities, reduce product color, and improve product purity. However, this method is a post-processing procedure for BPA products. It requires dissolving the BPA product first, followed by steps such as alkali washing, water washing, acid washing, reduction, oxidation, water washing, secondary alkali washing, water washing, adsorption, separation, and drying. The process is complex and generates a large amount of waste liquid, which is not conducive to the industrial utilization of BPA and is only suitable for small-scale laboratory trials.

[0006] Currently, the largest downstream application of bisphenol A (BPA) in the world is the production of polycarbonate. Therefore, ensuring the quality of BPA products is of paramount importance. Developing a low-cost and simple method to improve the quality of BPA products is one of the important research directions in the BPA industry. Summary of the Invention

[0007] Currently, in the industrial production of bisphenol A, excess phenol is often used as a solvent and circulated in the system. However, during the circulation process, polyphenolic impurities generated by the reaction also accumulate in the system, thus affecting product quality. In order to remove these excess impurities in the mother liquor and some sulfonic acid groups detached from the catalyst, this invention uses a weakly basic adsorption resin and loads some functional groups on the resin, thereby removing polyphenolic impurities and sulfonic acid groups in the mother liquor and improving the quality of bisphenol A products.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A method for improving the quality of bisphenol A (BPA) products involves adding a resin adsorption bed to adsorb BPA mother liquor before it is recycled to the BPA reactor. The resin adsorption bed uses a modified resin obtained by functionalizing a base resin. The functionalization process includes the following steps: (1) Resin activation: The matrix resin is reacted with sulfuric acid aqueous solution to introduce sulfonic acid groups into the long chain of the matrix resin; (2) Quaternary ammonium grafting: The resin obtained in step (1) is reacted with a quaternizing agent in the presence of a crosslinking agent to graft quaternary ammonium groups; (3) Hydrophobic chain modification: The resin obtained in step (2) is reacted with a long-chain alkylsilane reagent to graft hydrophobic chains; (4) Metal coordination loading: The resin obtained in step (3) is impregnated into a transition metal ion solution to form metal coordination sites.

[0009] Furthermore, the matrix resin is a styrene-divinylbenzene copolymer, polyacrylate, or polystyrene-based macroporous adsorption resin, with a pore size of 80-200 nm and a specific surface area ≥380 m² / g.

[0010] Further, in step (1), the concentration of the sulfuric acid aqueous solution is 0.5~1 mol / L, the amount of sulfuric acid solution used is 3~5 g / g resin, the reaction time is 2~3 h, and the reaction temperature is 60~80 ℃.

[0011] Further, in step (2), the quaternizing agent is trimethylamine or dimethylethanolamine, the crosslinking agent is epichlorohydrin or 1,4-butanediol diglycidyl ether, the reaction solvent is ethanol, wherein the concentration of the quaternizing agent is 0.1~0.5 mol / L, the concentration of the crosslinking agent is 0.02~0.1 mol / L, the amount of the ethanol solution used is 1.2~1.5 g / g resin, the reaction temperature is 65~75℃, and the reaction time is 2~3 h.

[0012] Further, in step (3), the long-chain alkylsilane reagent is hexadecyltrimethoxysilane or octadecyltrimethoxysilane, the amount added is 3-8% of the resin mass, the reaction solvent is toluene or xylene, the mass concentration of the long-chain alkylsilane reagent is 1.5-4%, the reaction time is 8-16 h, and the reaction temperature is 65-75 ℃.

[0013] Further, in step (4), the transition metal ion is Fe³⁺ or Al³⁺, the concentration of the transition metal ion is 0.1~0.6 mol / L, the amount of transition metal ion solution used is 5~8 g / g resin, the impregnation time is 2~6 h, and the impregnation temperature is 40~60℃.

[0014] Furthermore, the adsorption temperature of the resin adsorption bed is 70℃, and the mass hourly space velocity of the resin adsorption bed is 3 h⁻¹. -1 .

[0015] The beneficial effects of this invention are: This invention provides a method for improving the quality of bisphenol A (BPA) products. Before the BPA mother liquor is recycled to the BPA reactor, a resin adsorption bed is added to adsorb the BPA mother liquor. The resin adsorption bed uses a modified resin obtained by functionalizing a base resin, such as a common commercial adsorption resin, styrene-divinylbenzene copolymer, polyacrylate, or polystyrene-based macroporous adsorption resin. Activation of the base resin using sulfuric acid aqueous solution facilitates further modification. Adding quaternary ammonium groups to the resin enables it to adsorb sulfonic acid groups such as p-hydroxybenzenesulfonic acid and p-sulfobenzoic acid from the BPA mother liquor. Grafting long-chain alkyl groups with hydrophobic properties onto the resin allows for the capture of polyphenolic impurities in the system through hydrophobic interactions and π-π stacking effects. Impregnation and adsorption of transition metal ions allows the transition metal ions to form stable chelates with the polyphenolic impurities, enhancing the selective adsorption capacity of the modified resin for polyphenolic impurities in the system. This achieves purification of the BPA mother liquor, thereby improving the quality of the bisphenol A product. Detailed Implementation

[0016] To make the technical means, features and effects of the present invention easier to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with specific implementation methods and embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0017] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 A method for improving the quality of bisphenol A (BPA) products involves adding a resin adsorption bed to adsorb BPA mother liquor before it is recycled to the BPA reactor. The resin adsorption bed uses a modified resin obtained by functionalizing styrene-divinylbenzene copolymer resin microspheres as the base resin. The functionalization process includes the following steps: (1) Resin activation: Take 100 g of styrene-divinylbenzene copolymer resin beads (pore size 120 nm, specific surface area 420 m² / g), add them to 400 g sulfuric acid solution (0.8 mol / L), heat to 70℃ and react for 2.5 h, then filter to separate the resin beads, and wash the filter cake twice with 200 mL of deionized water. (2) Quaternary ammonium grafting: The resin obtained in step (1) was added to an ethanol solution of 120 g trimethylamine and epichlorohydrin, wherein the concentration of trimethylamine was 0.3 mol / L and the concentration of epichlorohydrin was 0.05 mol / L. The temperature was raised to 65℃ and reacted for 3 h. The resin pellets were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (3) Hydrophobic chain modification: The resin obtained in step (2) and 5 g of hexadecyltrimethoxysilane were added to 200 g of toluene, heated to 70 °C and reacted for 12 h. The resin pellets were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (4) Metal coordination loading: The resin obtained in step (3) was impregnated in 800 g FeCl3 solution (FeCl3 concentration is 0.2 mol / L) and kept at 40℃ for 4 h. The resin balls were then separated by filtration and the filter cake was washed twice with 200 mL of deionized water to obtain the modified resin.

[0019] Example 2 A method for improving the quality of bisphenol A (BPA) products involves adding a resin adsorption bed to adsorb BPA mother liquor before it is recycled to the BPA reactor. The resin adsorption bed uses a modified resin obtained by functionalizing polyacrylate resin microspheres as the base resin. The functionalization process includes the following steps: (1) Resin activation: Take 100 g of polyacrylate resin microspheres (pore size 80 nm, specific surface area 380 m² / g), add them to 300 g of sulfuric acid solution (0.5 mol / L), heat to 60℃ and react for 3 h, then filter to separate the resin microspheres, and wash the filter cake twice with 200 mL of deionized water. (2) Quaternary ammonium grafting: The resin obtained in step (1) was added to an ethanol solution of 135 g dimethyl ethanolamine and 1,4-butanediol diglycidyl ether, wherein the concentration of dimethyl ethanolamine was 0.1 mol / L and the concentration of 1,4-butanediol diglycidyl ether was 0.02 mol / L. The mixture was heated to 70℃ and reacted for 2.5 h. The resin pellets were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (3) Hydrophobic chain modification: The resin obtained in step (2) and 3 g of octadecyltrimethoxysilane were added to 200 g of xylene, heated to 65℃ and reacted for 16 h. The resin balls were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (4) Metal coordination loading: The resin microspheres obtained in step (3) were immersed in 600 g AlCl3 solution (AlCl3 concentration of 0.1 mol / L) and kept at 60℃ for 6 h. The resin microspheres were then separated by filtration and the filter cake was washed twice with 200 mL of deionized water to obtain modified resin.

[0020] Example 3 A method for improving the quality of bisphenol A (BPA) products involves adding a resin adsorption bed to adsorb BPA mother liquor before it is recycled to the BPA reactor. The resin adsorption bed uses a modified resin obtained by functionalizing polystyrene macroporous resin microspheres as the base resin. The functionalization process includes the following steps: (1) Resin activation: Take 100g of polystyrene macroporous resin microspheres (pore size 200 nm, specific surface area 450 m² / g), add them to 500 g sulfuric acid solution (1 mol / L), heat to 80℃ and react for 2 h, then filter to separate the resin microspheres, and wash the filter cake twice with 200 mL of deionized water. (2) Quaternary ammonium grafting: The resin obtained in step (1) was added to an ethanol solution of 150 g trimethylamine and epichlorohydrin, wherein the concentration of trimethylamine was 0.5 mol / L and the concentration of epichlorohydrin was 0.1 mol / L. The mixture was heated to 75℃ and reacted for 2 h. The resin pellets were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (3) Hydrophobic chain modification: The resin obtained in step 2 and 8 g of octadecyltrimethoxysilane were added to 200 g of toluene, heated to 75℃ and reacted for 8 h. The resin beads were then separated by filtration and the filter cake was washed twice with 200 mL of ethanol. (4) Metal coordination loading: The resin microspheres obtained in step (3) were immersed in 500 g Fe2(SO4)3 solution (Fe2(SO4)3 concentration was 0.3 mol / L) and kept at 50℃ for 2 h. The resin microspheres were then separated by filtration and the filter cake was washed twice with 200 mL of deionized water to obtain modified resin.

[0021] Comparative Examples 1-3 Take the matrix resins used in Examples 1-3, styrene-divinylbenzene copolymer resin microspheres, polyacrylate resin microspheres, and polystyrene macroporous resin microspheres respectively, and record them as Comparative Examples 1-3.

[0022] The modified resins prepared in Examples 1-3 and Comparative Examples 1-3 were respectively packed into an adsorption bed with a resin loading amount of 80g, the adsorption bed temperature was controlled at 70℃, and the bisphenol A mother liquor feed rate was 240g / h. Control samples were taken at 1h, 10h, 30h and 80h respectively to detect the residual sulfonic acid groups and polyphenol impurities. The specific results are shown in Table 1.

[0023] The composition of the bisphenol A mother liquor was as follows: phenol: 71.5%; bisphenol A: 18.6%; 2,4-isomeric bisphenol A: 4.9%; polyphenolic impurities: 4.1%; sulfonic acid group content: 4.5 ppm. (All the above contents are normalized contents obtained by liquid chromatography. The normalized contents of the bisphenol A mother liquor after adsorption were also obtained by liquid chromatography under the same conditions.) Table 1 Comparison of the effects of resin adsorption on bisphenol A mother liquor Note: Control 1 is the 1-hour control sample, Control 2 is the 10-hour control sample, Control 3 is the 30-hour control sample, and Control 4 is the 80-hour control sample; nd indicates not detected. The data from the 1-hour and 10-hour control samples of Comparative Examples 1-3 show that the resins of Comparative Examples 1-3 have extremely poor adsorption effects on bisphenol A mother liquor, and no further adsorption tests were conducted. Data for the 30-hour and 80-hour control samples were not obtained.

[0024] Comparing the analysis data of the central control samples at different time periods, it can be found that the three unmodified matrix resins have almost no significant removal ability for sulfonic acid groups and polyphenolic impurities in the system; the three modified resins can almost completely remove sulfonic acid groups in the system, and the removal efficiency for polyphenolic impurities is over 80%.

[0025] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the quality of bisphenol A products, characterized in that, Before the BPA mother liquor is recycled to the BPA reactor, a resin adsorption bed is added to adsorb the BPA mother liquor. The resin adsorption bed uses a modified resin obtained by functionalizing a base resin. The functionalization process includes the following steps: (1) Resin activation: The matrix resin is reacted with sulfuric acid aqueous solution to introduce sulfonic acid groups into the long chain of the matrix resin; (2) Quaternary ammonium grafting: The resin obtained in step (1) is reacted with a quaternizing agent in the presence of a crosslinking agent to graft quaternary ammonium groups; (3) Hydrophobic chain modification: The resin obtained in step (2) is reacted with a long-chain alkylsilane reagent to graft hydrophobic chains; (4) Metal coordination loading: The resin obtained in step (3) is impregnated into a transition metal ion solution to form metal coordination sites.

2. The method for improving the quality of bisphenol A products as described in claim 1, characterized in that, The matrix resin is a styrene-divinylbenzene copolymer, polyacrylate, or polystyrene-based macroporous adsorption resin, with a pore size of 80-200 nm and a specific surface area ≥380 m² / g.

3. The method for improving the quality of bisphenol A products as described in claim 1, characterized in that, In step (1), the concentration of the sulfuric acid aqueous solution is 0.5~1 mol / L, the amount of sulfuric acid solution used is 3~5 g / g resin, the reaction time is 2~3 h, and the reaction temperature is 60~80 ℃.

4. The method for improving the quality of bisphenol A products as described in claim 1, characterized in that, In step (2), the quaternizing agent is trimethylamine or dimethylethanolamine, the crosslinking agent is epichlorohydrin or 1,4-butanediol diglycidyl ether, the reaction solvent is ethanol, wherein the concentration of the quaternizing agent is 0.1~0.5 mol / L, the concentration of the crosslinking agent is 0.02~0.1 mol / L, the amount of ethanol solution used is 1.2~1.5 g / g resin, the reaction temperature is 65~75℃, and the reaction time is 2~3 h.

5. The method for improving the quality of bisphenol A products as described in claim 1, characterized in that, In step (3), the long-chain alkylsilane reagent is hexadecyltrimethoxysilane or octadecyltrimethoxysilane, and its addition amount is 3-8% of the resin mass. The reaction solvent is toluene or xylene, wherein the mass concentration of the long-chain alkylsilane reagent is 1.5-4%, the reaction time is 8-16 h, and the reaction temperature is 65-75 ℃.

6. The method for improving the quality of bisphenol A products as described in claim 1, characterized in that, In step (4), the transition metal ion is Fe³⁺ or Al³⁺, the concentration of the transition metal ion is 0.1~0.6 mol / L, the amount of transition metal ion solution used is 5~8 g / g resin, the impregnation time is 2~6 h, and the impregnation temperature is 40~60 ℃.

7. The method for improving the quality of bisphenol A products as described in claims 1-6, characterized in that, The adsorption temperature of the resin adsorption bed is 70℃, and the mass hourly space velocity of the resin adsorption bed is 3 h⁻¹. -1 .

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