A method for preparing bisphenol A polyoxyethylene ether

Abstract

This invention discloses a method for preparing bisphenol A polyoxyethylene ether. The method includes the following steps: bisphenol A and ethylene oxide are melt-reacted in the presence of a bisphenol A-type alkaline earth metal catalyst to prepare bisphenol A polyoxyethylene ether; the preparation method of the bisphenol A-type alkaline earth metal catalyst is as follows: bisphenol A is dissolved in a solvent, acetic anhydride is added, the temperature is raised to 75-85℃ and stirred for 15-35 min, then calcium hydroxide is added and the temperature is raised to 80-100℃ and stirred for 1-1.5 h; then concentrated sulfuric acid is continuously added dropwise over 10-15 min, and the reaction is carried out at 85-95℃ for 1-2 h; the product is vacuum-removed of water and solvent to obtain the bisphenol A-type alkaline earth metal catalyst.

Description

Technical Field

[0001] This invention relates to a preparation method, and more particularly to a method for preparing bisphenol A polyoxyethylene ether. Background Technology

[0002] Bisphenol A polyoxyethylene ether is prepared by reacting bisphenol A, an initiator, with epoxides. Its molecular structure contains aromatic rings and carbon-oxygen segments, which imparts a certain degree of rigidity and toughness to the material. By adjusting the ratio of the two components, bisphenol A polyether products with specific properties can be obtained, effectively compensating for the inherent defects of the material and improving its performance. Bisphenol A polyoxyethylene ether can be used in UV curing, as well as in polyurethane elastomers and coating adhesives. Furthermore, as a toughening agent for cathodic electrophoretic paints, it can effectively improve the flexibility, corrosion resistance, and mechanical strength of the electrophoretic paint.

[0003] The preparation processes of bisphenol A polyoxyethylene ether mainly include solvent method and melt method. The solvent method can achieve the reaction between bisphenol A and epoxides at lower temperatures, resulting in products with superior color and quality. However, its disadvantages include high energy consumption for solvent recycling and solvent loss, leading to higher production costs. From this perspective, the melt method, which involves feeding solid bisphenol A and melting it into a liquid state at high temperatures before stirring, is more suitable for industrial applications. However, the melt method has the disadvantage of requiring high temperatures to maintain the molten state of bisphenol A. Under high-temperature conditions, the reaction of conventional strong base catalysts with epoxides can result in products with darker colors and a wider molecular weight distribution, affecting downstream high-end applications.

[0004] Patent CN109265323B describes a method for preparing bisphenol A polyoxyethylene ether with a narrow molecular weight distribution by first reacting ethylene carbonate with bisphenol A under alkaline catalyst, then adding ethylene oxide for an addition reaction, followed by neutralization with acetic acid. However, ethylene carbonate readily decomposes under alkaline conditions to produce ethylene glycol and carbon dioxide, suggesting a potentially low yield for this method.

[0005] Patent CN113754876A uses organic alkoxy alkaline earth metals as mild catalysts. Compared with other organic base catalysts, it has lower alkalinity, resulting in lower peroxide value and color of the product. However, it does not solve the problem of product molecular weight distribution. Moreover, organic catalysts such as magnesium isopropoxide and barium polyethylene glycol will generate byproducts such as isopropanol polyoxyethylene ether and polyethylene glycol during the reaction, which will cause a decline in product quality.

[0006] In light of the numerous problems existing in the current technology, there is an urgent need to find a method for preparing bisphenol A polyoxyethylene ether with low color intensity and narrow color distribution, while not introducing byproducts. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a method for preparing bisphenol A polyoxyethylene ether. Addressing the issue of byproducts generated by organic alkaline earth catalysts in existing melt-processing methods for preparing bisphenol A polyoxyethylene ether, this invention first prepares a bisphenol A-type alkaline earth metal catalyst. In the presence of this catalyst, the reaction byproducts resulting from its introduction are themselves products, thus avoiding the generation of undesirable byproduct impurities and improving product quality. Furthermore, no further impurity removal is required for high-end applications, broadening the product's applicability. Simultaneously, the bisphenol A polyoxyethylene ether prepared according to this invention has the advantages of a narrow molecular weight distribution and low color intensity.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing bisphenol A polyoxyethylene ether includes the following steps:

[0010] Bisphenol A polyoxyethylene ether is prepared by melting and reacting bisphenol A and ethylene oxide in the presence of a bisphenol A-type alkaline earth metal catalyst; the preparation method of the bisphenol A-type alkaline earth metal catalyst is as follows:

[0011] Bisphenol A was dissolved in a solvent and acetic anhydride was added. The mixture was heated to 75-85℃ and stirred for 15-35 min. Calcium hydroxide was then added and the mixture was heated to 80-100℃ and stirred for 1-1.5 h. Concentrated sulfuric acid was then added dropwise over 10-15 min, and the mixture was reacted at 85-95℃ for 1-2 h. The product was then dehydrated and the solvent was removed under vacuum to obtain a bisphenol A-type alkaline earth metal catalyst.

[0012] In the preparation method of the catalyst described above in this invention, the bisphenol A-type alkaline earth metal catalyst prepared from bisphenol A as a raw material generates bisphenol A polyoxyethylene ether as a byproduct during product preparation. This avoids the byproducts of isopropanol polyoxyethylene ether and polyethylene glycol generated by conventional calcium isopropoxide and calcium hydroxide catalysts. These byproducts lack benzene ring structures, have weak rigidity, and limit the application of the product in high-end industries. The possible reaction mechanism is that the introduction of acetic anhydride can effectively enhance the complexation of bisphenol A with calcium ions, allowing it to disperse uniformly in the system and generate a bisphenol A-based calcium salt catalyst. Finally, the introduction of concentrated sulfuric acid as a co-catalyst can shorten the catalytic induction period and improve the catalyst activity.

[0013] In some examples, the molar ratio of bisphenol A, acetic anhydride, and calcium hydroxide in the preparation method of the bisphenol A type alkaline earth metal catalyst is (3-4):(0.8-1):1.

[0014] In some examples, the molar ratio of the concentrated sulfuric acid to calcium hydroxide is (0.2-0.3):1.

[0015] In some examples, the concentrated sulfuric acid has a mass concentration of 98%.

[0016] In some examples, the solvent in the preparation method of the bisphenol A type alkaline earth metal catalyst is one or both of diethylene glycol dimethyl ether and ethylene glycol dimethyl ether.

[0017] In some examples, the amount of solvent added is such that the mass concentration of bisphenol A after dissolving in the solvent is 55-65%.

[0018] In some examples, the amount of bisphenol A-type alkaline earth metal catalyst added in the melt reaction is 0.4-0.8% of the mass of bisphenol A.

[0019] In some examples, the reaction temperature for the melting reaction is 160-165°C.

[0020] In some examples, the molar ratio of bisphenol A to ethylene oxide in the melt reaction is (2-10):1.

[0021] The beneficial effects of this invention are as follows:

[0022] 1) This invention uses a bisphenol A-type alkaline earth metal catalyst to catalyze the reaction of bisphenol A and ethylene oxide. The catalyst grafted with ethylene oxide still produces bisphenol A polyoxyethylene ether, which will not introduce byproducts into the product and is beneficial to improving product quality.

[0023] 2) The bisphenol A type alkaline earth metal catalyst used in this invention is a mild catalyst, and the resulting bisphenol A polyoxyethylene ether has the advantages of low color and narrow molecular weight distribution. Detailed Implementation

[0024] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0025] Unless otherwise specified, all raw materials and reagents used in the following examples were purchased from commercially available sources.

[0026] The main detection methods involved include:

[0027] Hydroxyl value: The hydroxyl value was determined according to the acetic anhydride method in GB / T 7383-2007.

[0028] APHA colorimetry: Color number determination is performed according to the national standard GB / T9282.1-2008;

[0029] Polymer Dispersion Index (PDI): Measured using a PL-GPC220 gel permeation chromatograph with tetrahydrofuran as the mobile phase.

[0030] The content of by-products was determined by liquid chromatography: column C18*4.6mm*250mm*5μm, column temperature 40℃, mobile phase methanol / water = 80 / 20.

[0031]

Example 1

[0032] (1) Preparation of bisphenol A type alkaline earth metal catalyst:

[0033] 684g of bisphenol A raw material was weighed and dissolved in 559.6g of diethylene glycol dimethyl ether solvent by stirring. Then, 81.6g of acetic anhydride was added, and the mixture was stirred at 75°C for 15 min. Next, 74g of calcium hydroxide was added, and the mixture was stirred at 80°C for 1 h. Subsequently, 10g of 98% concentrated sulfuric acid was added dropwise over 10 min, and the reaction was carried out at 85°C for 1 h. The resulting product was then subjected to vacuum at 90°C to remove water and diethylene glycol dimethyl ether, yielding a bisphenol A-type alkaline earth metal catalyst.

[0034] (2) Preparation of bisphenol A polyoxyethylene ether

[0035] 228g of solid bisphenol A and 0.92g of the bisphenol A-type alkaline earth metal catalyst prepared in the previous steps were added to the reactor. Stirring was started, and the temperature was raised to 160°C. Then, 264g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. The reactor was then cooled to 80°C to obtain the product bisphenol A polyoxyethylene ether BPE6. The product had a hydroxyl value of 227.9mgKOH / g, a color of 5 hazen, and a PDI of 1.033. No non-bisphenol A polyether byproducts were detected.

[0036]

Example 2

[0037] (1) Preparation of bisphenol A type alkaline earth metal catalyst:

[0038] 912g of bisphenol A raw material was weighed and dissolved in 491.1g of ethylene glycol dimethyl ether solvent by stirring. Then, 102g of acetic anhydride was added, and the mixture was stirred at 85℃ for 35 min. Next, 74g of calcium hydroxide was added, and the mixture was stirred at 100℃ for 1.5 h. Subsequently, 20g of 98% concentrated sulfuric acid was added dropwise over 15 min, and the reaction was carried out at 95℃ for 2 h. The resulting product was then subjected to vacuum at 60℃ to remove water and ethylene glycol dimethyl ether, yielding a bisphenol A-type alkaline earth metal catalyst.

[0039] (2) Preparation of bisphenol A polyoxyethylene ether

[0040] 228g of bisphenol A solid and 1.82g of the bisphenol A-type alkaline earth metal catalyst prepared in the previous steps were added to the reactor. Stirring was started, and the temperature was raised to 165°C. Then, 264g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. The reactor was then cooled to 80°C to obtain the product bisphenol A polyoxyethylene ether BPE6. The product had a hydroxyl value of 228.8mgKOH / g, a color of 9 hazen, and a PDI of 1.035. No non-bisphenol A polyether byproducts were detected.

[0041]

Example 3

[0042] (1) Preparation of bisphenol A type alkaline earth metal catalyst:

[0043] 700g of bisphenol A raw material was weighed and dissolved in 466g of diethylene glycol dimethyl ether solvent by stirring. Then, 90g of acetic anhydride was added, and the mixture was stirred at 80℃ for 20min. Next, 74g of calcium hydroxide was added, and the mixture was stirred at 90℃ for 1h. Subsequently, 15g of 98% concentrated sulfuric acid was added dropwise over 12min, and the reaction was carried out at 90℃ for 1.5h. The resulting product was then subjected to vacuum at 90℃ to remove water and diethylene glycol dimethyl ether, yielding a bisphenol A-type alkaline earth metal catalyst.

[0044] (2) Preparation of bisphenol A polyoxyethylene ether

[0045] 228g of bisphenol A solid and 1.56g of the bisphenol A-type alkaline earth metal catalyst prepared in the previous steps were added to the reactor. Stirring was started, and the temperature was raised to 162°C. Then, 88g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. The reactor was then cooled to 80°C to obtain the product bisphenol A polyoxyethylene ether BPE2. The product had a hydroxyl value of 355.1mgKOH / g, a color of 7 hazen, and a PDI of 1.032. No non-bisphenol A polyether byproducts were detected.

[0046]

Example 4

[0047] (1) Preparation of bisphenol A type alkaline earth metal catalyst:

[0048] 885g of bisphenol A raw material was weighed and dissolved in 542.2g of ethylene glycol dimethyl ether solvent by stirring. Then, 99.8g of acetic anhydride was added, and the mixture was stirred at 80℃ for 20min. 74g of calcium hydroxide was then added, and the mixture was stirred at 92℃ for 1.2h. Subsequently, 16g of 98% concentrated sulfuric acid was added dropwise over 13min, and the reaction was carried out at 92℃ for 1.7h. The resulting product was then subjected to vacuum at 60℃ to remove water and diethylene glycol dimethyl ether, yielding a bisphenol A-type alkaline earth metal catalyst.

[0049] (2) Preparation of bisphenol A polyoxyethylene ether

[0050] 228g of solid bisphenol A and 1.56g of the bisphenol A-type alkaline earth metal catalyst prepared in the previous steps were added to the reactor. Stirring was started, and the temperature was raised to 163°C. Then, 440g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. The reactor was then cooled to 80°C to obtain the product bisphenol A polyoxyethylene ether BPE10. The product had a hydroxyl value of 167.9mgKOH / g, a color of 6 hazen, and a PDI of 1.033. No non-bisphenol A polyether byproducts were detected.

[0051] Comparative Example 1

[0052] 228g of bisphenol A solid and 0.92g of potassium hydroxide catalyst were added to the reactor. Stirring was started, and the temperature was raised to 160℃. Then, 264g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. After cooling to 80℃, 1.01g of acetic acid was added for neutralization to obtain the product bisphenol A polyoxyethylene ether BPE6. The product had a hydroxyl value of 228.3mgKOH / g, a color of 20 hazen, and a PDI of 1.084. The content of non-bisphenol A polyether byproducts (polyethylene glycol) in the product was detected to be 1.6wt%.

[0053] Comparative Example 2

[0054] 228g of bisphenol A solid and 0.92g of calcium isopropoxide catalyst were added to the reactor. Stirring was started, and the temperature was raised to 160℃. Then, 264g of ethylene oxide was introduced to start the reaction. After the feeding was completed, the reactor was aged until the pressure no longer decreased. The reactor was then cooled to 80℃ to obtain the product bisphenol A polyoxyethylene ether BPE6. The product had a hydroxyl value of 227.6mgKOH / g, a color of 10 hazen, and a PDI of 1.052. The content of non-bisphenol A polyether byproduct (isopropoxide polyoxyethylene ether) in the product was detected to be 0.6wt%.

[0055] Comparative Example 3

[0056] Bisphenol A polyoxyethylene ether was prepared using essentially the same method as in Example 1, except that calcium hydroxide was replaced with the same molar amount of potassium hydroxide when preparing the bisphenol A type alkaline earth metal catalyst. The product obtained was bisphenol A polyoxyethylene ether BPE6, with a hydroxyl value of 228.5 mg KOH / g, a color of 12 hazen, and a PDI of 1.082. No non-bisphenol A polyether byproducts were detected.

[0057] The test results above show that the bisphenol A polyoxyethylene ether prepared by this invention does not contain non-bisphenol A polyether byproducts, and has a narrow molecular weight distribution and low color intensity, which has significant application advantages compared with existing solutions.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing bisphenol A polyoxyethylene ether, characterized in that, Includes the following steps: Bisphenol A polyoxyethylene ether is prepared by melting and reacting bisphenol A and ethylene oxide in the presence of a bisphenol A-type alkaline earth metal catalyst. The amount of bisphenol A-type alkaline earth metal catalyst added during the melting reaction is 0.4-0.8% of the mass of bisphenol A. The preparation method of the bisphenol A-type alkaline earth metal catalyst is as follows: Bisphenol A was dissolved in a solvent and acetic anhydride was added. The mixture was heated to 75-85℃ and stirred for 15-35 min. Then, calcium hydroxide was added and the mixture was heated to 80-100℃ and stirred for 1-1.5 h. Concentrated sulfuric acid was then added dropwise over 10-15 min, and the mixture was reacted at 85-95℃ for 1-2 h. The product was then dehydrated and the solvent was removed under vacuum to obtain a bisphenol A-type alkaline earth metal catalyst. In the preparation method of the bisphenol A type alkaline earth metal catalyst, the molar ratio of bisphenol A, acetic anhydride and calcium hydroxide is (3-4):(0.8-1):

1. The molar ratio of concentrated sulfuric acid to calcium hydroxide is (0.2-0.3):

1.

2. The method for preparing bisphenol A polyoxyethylene ether according to claim 1, characterized in that, The concentrated sulfuric acid has a mass concentration of 98%.

3. The method for preparing bisphenol A polyoxyethylene ether according to claim 1, characterized in that, In the preparation method of the bisphenol A type alkaline earth metal catalyst, the solvent is one or both of diethylene glycol dimethyl ether and ethylene glycol dimethyl ether.

4. The method for preparing bisphenol A polyoxyethylene ether according to claim 1, characterized in that, The amount of solvent added is such that the mass concentration of bisphenol A after dissolving in the solvent is 55-65%.

5. The method for preparing bisphenol A polyoxyethylene ether according to any one of claims 1-4, characterized in that, The reaction temperature for the melting reaction is 160-165℃.

6. The method for preparing bisphenol A polyoxyethylene ether according to any one of claims 1-4, characterized in that, In the melting reaction, the molar ratio of bisphenol A to ethylene oxide is (2-10):1.