Production method for reducing TMPTA residues in EO3TMPTA product
By combining modified hydrotalcite catalyst with suitable reaction conditions, the problems of high TMPTA residue and high color number in EO3TMPTA products were solved, achieving efficient preparation of EO3TMPTA products and meeting the application requirements of low residue and low color number.
Patent Information
- Application Number
- CN202511610329.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-02-06
AI Technical Summary
Existing technologies cannot reduce the residual TMPTA content in EO3TMPTA products to <1%, and traditional catalysts are prone to discoloration at high temperatures, resulting in a higher product color number that cannot meet application requirements.
Modified hydrotalcite was used as a catalyst. The strength and activity of the catalyst were improved by soaking and calcining the modified hydrotalcite and granulating it with aluminum silicate. Combined with suitable reaction conditions and filtration separation technology, EO3TMP and EO3TMPTA were prepared.
The residual TMPTA content in the EO3TMPTA product is less than 1%, avoiding high-temperature discoloration and ensuring that the product color number is ≤20, meeting application requirements.
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Abstract
Description
Technical Field
[0001] This invention relates to a production method for reducing TMPTA residue in EO3TMPTA products, specifically a production method for reducing TMPTA residue in EO3TMPTA products to <1%. Background Technology
[0002] EO3TMPTA (triethoxylated trimethylolpropane triacrylate) is mainly used in cable coatings and printing inks for food and cigarette packaging. With its increasing application in cigarette and food packaging, the residual amount of TMPTA (trimethylolpropane triacrylate) in EO3TMPTA is required to be less than 1%; the lower the TMPTA residue, the better the flexibility and the less toxic the product.
[0003] The reaction pathway of EO3TMPTA is as follows:
[0004]
[0005]
[0006] include:
[0007] Step (1): Using trimethylolpropane (TMP) and ethylene oxide (EO) as raw materials, EO3TMP (triethoxylated trimethylolpropane) is generated under the action of a catalyst. EO3TMP is directly used in the next step of the reaction.
[0008] Step (2): EO3TMP and acrylic acid are esterified to obtain EO3TMPTA.
[0009] The traditional preparation process of EO3TMPTA uses KOH as a catalyst in the first step to prepare EO3TMP. After numerous experiments, the inventors discovered that approximately 5-7% TMP remains in EO3TMP. TMP is difficult to remove and consumes a lot of energy. Furthermore, EO3TMP discolors at high temperatures during the process, resulting in a higher color grade in the EO3TMPTA product, failing to meet the requirement of a color grade ≤20. If the product from the first step is directly used in the second step, the residual TMPTA content in the EO3TMPTA will be excessively high, far exceeding 1%.
[0010] The inventors aimed to solve the problems existing in traditional preparation processes by screening suitable catalysts. Hydrotalcite is a natural Lewis acid. The inventors attempted to use various hydrotalcite catalysts to catalyze the reaction of trimethylolpropane and ethylene oxide to prepare EO3TMP. The hydrotalcite catalyst SFCAT-01 showed the best results, reducing the TMP residue to nearly 1%. However, after repeated experiments, it was found that the TMP residue was still greater than 1%, and the TMPTA residue in the EO3TMPTA product could not be reduced to <1%.
[0011] Furthermore, hydrotalcite has poor strength and turns into fine powder after stirring. Due to its adsorption properties and good adhesion, it forms a colloid with EO3TMP, making it difficult to separate hydrotalcite and EO3TMP by centrifugation. Considering that hydrotalcite is insoluble in water, the inventors separated it from the reactants by adding 40% water by weight of the total materials. However, the dehydration of EO3TMP is energy-intensive, making this method unsuitable.
[0012] The inventors attempted to improve the strength of hydrotalcite by granulating and calcining it with aluminum silicate, and then using it to catalyze the reaction of trimethylolpropane and ethylene oxide to prepare EO3TMP. Experiments showed that the catalyst and EO3TMP could be separated by filtration, and the residual amount of TMP in EO3TMP was less than 1%. However, the inventors found that the reaction between trimethylolpropane and ethylene oxide was slow. To shorten the reaction time, the inventors further increased the amount of catalyst and the reaction temperature, but the effect was not significant (Comparative Example 1). Summary of the Invention
[0013] The purpose of this invention is to provide a production method for reducing TMPTA residue in EO3TMPTA products to <1%.
[0014] The objective of this invention is achieved through the following technical solution:
[0015] A modified hydrotalcite is prepared by first soaking hydrotalcite in a KOH aqueous solution, then granulating the soaked hydrotalcite with aluminum silicate, and finally calcining it at 800–850°C.
[0016] The KOH aqueous solution has a mass fraction of 20%.
[0017] The magnesium-aluminum ratio of the hydrotalcite is 3.7:1.
[0018] Specifically, the hydrotalcite can be the hydrotalcite catalyst SFCAT-01.
[0019] The soaking treatment was performed at room temperature.
[0020] The mass ratio of the hydrotalcite to aluminum silicate is 4:1.
[0021] The roasting time is 3 to 3.5 hours.
[0022] The modified hydrotalcite and EO3TMP described in this invention can be separated by filtration.
[0023] A production method for reducing TMPTA residue in EO3TMPTA products, comprising:
[0024] Step (1): Using the modified hydrotalcite as a catalyst, trimethylolpropane and ethylene oxide react under a nitrogen atmosphere. After the reaction is complete, the modified hydrotalcite is separated by filtration to obtain EO3TMP.
[0025] Step (2): Under the action of a catalyst, EO3TMP and acrylic acid undergo an esterification reaction to obtain EO3TMPTA.
[0026] In step (1), the molar ratio of trimethylolpropane to ethylene oxide is 1:3 to 1:3.25.
[0027] Specifically, the molar ratio of trimethylolpropane to ethylene oxide can be 1:3.
[0028] The modified hydrotalcite is used in an amount of 1-3%wt of the total amount of trimethylolpropane and ethylene oxide, preferably 1.5-2.5%wt.
[0029] The reaction temperature is 92–115°C, and the reaction pressure is -0.8 MPa–0.45 MPa, preferably -0.8 MPa–0.12 MPa.
[0030] The residual TMP content in the EO3TMP is less than 1%.
[0031] Preferably, trimethylolpropane and modified hydrotalcite are added to the reaction apparatus, and nitrogen is used for purging. Under a nitrogen atmosphere and a pressure of approximately -0.08 MPa, 7-8% of the total ethylene oxide is added, and stirring is started. When the temperature rises to 92-97°C, ethylene oxide is added continuously, and the temperature is controlled at 105-115°C and the pressure at approximately 0.12 MPa. The remaining ethylene oxide is added in batches over 4-5 hours. After the addition is complete, the reaction continues at a temperature of 105-115°C and a pressure of approximately 0.12 MPa for 1-2 hours. After the reaction is completed, the mixture is filtered to separate the modified hydrotalcite, yielding EO3TMP.
[0032] In step (2), acrylic acid is used in excess to ensure complete reaction and yield. The molar ratio of EO3TMP to acrylic acid is 1:3.1 to 1:3.3.
[0033] Specifically, the molar ratio of EO3TMP to acrylic acid can be 1:3.3.
[0034] The reaction solvent for the esterification reaction is cyclohexane.
[0035] The catalyst is methanesulfonic acid; the amount of the catalyst used is 0.15 to 0.2% wt of the total amount of EO3TMP and acrylic acid.
[0036] The esterification reaction is carried out at a temperature of 70–90°C.
[0037] Preferably, EO3TMP, acrylic acid, reaction solvent, and catalyst are added to the reaction apparatus, stirring is started, and esterification reaction is carried out at a temperature of 70-90°C. Water generated is removed during the reaction. After no water is removed, the mixture is washed successively with a 16% sodium carbonate aqueous solution and water, and then the reaction solvent is removed to obtain EO3TMPTA.
[0038] The temperature for removing the solvent in the reaction is 80°C and the pressure is -0.095 MPa.
[0039] The beneficial effects of this invention are:
[0040] The modified hydrotalcite of this invention has stronger Lewis acidity and higher strength. When used to catalyze the reaction of trimethylolpropane and ethylene oxide to prepare EO3TMP, it exhibits higher catalytic activity and reaction selectivity, shortens the reaction cycle, and allows the modified hydrotalcite to be separated by filtration. The residual TMP in EO3TMP is less than 1%, ensuring that the residual TMPTA in the EO3TMPTA product is reduced to <1%.
[0041] The modified hydrotalcite of this invention can catalyze the reaction of trimethylolpropane and ethylene oxide at a lower temperature (not exceeding 115°C) to prepare EO3TMP, avoiding discoloration of EO3TMP at higher temperatures and ensuring that the color number of EO3TMPTA is ≤20. Detailed Implementation
[0042] The technical solution of the present invention will be further described in detail below through specific embodiments.
[0043] This invention uses the platinum-cobalt standard colorimetric method to test colorimetry.
[0044] Example 1
[0045] A method for preparing modified hydrotalcite includes the following steps: hydrotalcite catalyst SFCAT-01 (magnesium-aluminum ratio 3.7:1) is soaked in a 20% KOH aqueous solution at room temperature for 12 hours, filtered, and aluminum silicate is added at a mass ratio of 4:1 (SFCAT-01 to aluminum silicate (Al2(SiO3)3)) to granulate (particle size 0.25 cm). The granules are then placed in a calcining furnace and calcined at approximately 850°C for 3 hours to obtain modified hydrotalcite.
[0046] Example 2
[0047] 1103g TMP and 34g of the modified hydrotalcite prepared in Example 1 were added to the reactor. The reactor was purged with nitrogen three times. 80g EO was added under a slight negative pressure (approximately -0.08MPa). The temperature was raised and stirring was started. When the temperature reached 97℃, EO was added again. The temperature was controlled at 105-115℃ and the pressure at approximately 0.12MPa. EO was added in batches over 5 hours, for a total of 1085g EO. After the addition was completed, the reaction was continued at 105-115℃ and approximately 0.12MPa for 2 hours. After the reaction was completed, the material was cooled to 80℃, filtered, and the modified hydrotalcite was separated to obtain 2140g EO3TMP, with a hydroxyl value of 620mmgKOH / g, a TMP residue of 0.68%, a color number of 8, and a yield of 97.8%.
[0048] Add 302g EO3TMP (TMP residue 0.68%, color number 8), 270g acrylic acid, 130g cyclohexane, and 1g methanesulfonic acid (catalyst) to a 1L esterification flask. Start stirring and heat to 70℃ to begin the esterification reaction. Remove the generated water while reacting. React at 70-90℃ for 5 hours. After no water is removed, wash with a 16% sodium carbonate aqueous solution, then wash with water. Remove the solvent (cyclohexane) at 80℃ and a vacuum of -0.095MPa to obtain 513g EO3TMPTA sample with a TMPTA content of 0.87% and color number 18, which meets the standard.
[0049] Example 3
[0050] 1084g TMP and 45g of the modified hydrotalcite prepared in Example 1 were added to the reactor. The reactor was purged with nitrogen three times. 80g EO was added under a slight negative pressure (approximately -0.08MPa). The temperature was raised and stirring was started. When the temperature reached 92℃, EO was added again. The temperature was controlled at 105-115℃ and the pressure at approximately 0.12MPa. EO was added in batches over 4 hours, for a total of 1066g EO. After the addition was completed, the reaction was continued for 2 hours at a temperature of 105-115℃ and a pressure of approximately 0.12MPa. After the reaction was completed, the material was cooled to 80℃, filtered, and the modified hydrotalcite was separated to obtain 2105g EO3TMP, with a hydroxyl value of 616mmgKOH / g, a TMP residue of 0.7%, a color number of 17, and a yield of 97.9%.
[0051] Example 4
[0052] 1048g TMP and 52g of the modified hydrotalcite prepared in Example 1 were added to the reactor. The reactor was purged with nitrogen three times. 80g EO was added under a slight negative pressure (approximately -0.08MPa). The temperature was raised and stirring was started. When the temperature reached 95℃, EO was added again. The temperature was controlled at 105-115℃ and the pressure at approximately 0.12MPa. EO was added in batches over 4 hours, for a total of 1032g EO. After the addition was completed, the reaction was continued for 2 hours at 105-115℃ and approximately 0.12MPa. After the reaction was completed, the material was cooled to 80℃, filtered, and the modified hydrotalcite was separated to obtain 2020g EO3TMp, with a hydroxyl value of 615mmgKOH / g, TMP residue of 0.75%, color number 19, and a yield of 97.1%.
[0053] Comparative Example 1
[0054] Catalyst preparation: Hydrotalcite catalyst SFCAT-01 (magnesium-aluminum ratio 3.7:1) and aluminum silicate were granulated at a mass ratio of 4:1 (particle size 0.25cm), placed in a calcining furnace, and calcined at about 850℃ for 3 hours to obtain the catalyst.
[0055] 1021g TMP and 45g catalyst were added to the reactor, purged with nitrogen three times, stirred, and heated to 110℃. EO was first added at 110℃ and -0.08MPa. The reaction was carried out at 115-125℃ and approximately 0.12 MPa for 8 hours. EO was added in batches over the 8 hours, totaling 1095g. After the addition was complete, the reaction continued at 115-125℃ and approximately 0.12 MPa for 4 hours. After the reaction was completed, the temperature was lowered to 80℃, and the catalyst was separated by filtration to obtain 2100g EO3TMP with a hydroxyl value of 613mmgKOH / g and a color number of 42.
Claims
1. A modified hydrotalcite, characterized in that: It is a modified hydrotalcite obtained by first soaking hydrotalcite in KOH aqueous solution, then granulating the soaked hydrotalcite with aluminum silicate, and calcining it at 800-850℃.
2. The modified hydrotalcite according to claim 1, characterized in that: The magnesium-aluminum ratio of the hydrotalcite is 3.7:
1.
3. The modified hydrotalcite according to claim 1 or 2, characterized in that: The hydrotalcite mentioned is hydrotalcite catalyst SFCAT-01.
4. The modified hydrotalcite according to claim 1, characterized in that: The mass ratio of the hydrotalcite to aluminum silicate is 4:
1.
5. A production method for reducing TMPTA residue in EO3TMPTA products, characterized in that: include: Step (1): Using the modified hydrotalcite as a catalyst, trimethylolpropane and ethylene oxide react under a nitrogen atmosphere. After the reaction is complete, the modified hydrotalcite is separated by filtration to obtain EO3TMP. Step (2): Under the action of a catalyst, EO3TMP and acrylic acid undergo an esterification reaction to obtain EO3TMPTA.
6. The production method for reducing TMPTA residue in EO3TMPTA products according to claim 5, characterized in that: In step (1), the molar ratio of trimethylolpropane to ethylene oxide is 1:3 to 1:3.25; the amount of modified hydrotalcite is 1 to 3% wt of the total amount of trimethylolpropane and ethylene oxide.
7. The production method for reducing TMPTA residue in EO3TMPTA products according to claim 5 or 6, characterized in that: In step (1), the amount of modified hydrotalcite used is 1.5 to 2.5% wt of the total amount of trimethylolpropane and ethylene oxide.
8. The production method for reducing TMPTA residue in EO3TMPTA products according to claim 5, characterized in that: In step (1), the reaction temperature is 92 to 115°C and the reaction pressure is -0.8 MPa to 0.45 MPa, preferably -0.8 MPa to 0.12 MPa.
9. The production method for reducing TMPTA residue in EO3TMPTA products according to claim 5, characterized in that: In step (2), the molar ratio of EO3TMP to acrylic acid is 1:3.1 to 1:3.
3.
10. The production method for reducing TMPTA residue in EO3TMPTA products according to claim 5, characterized in that: In step (2), the reaction solvent for the esterification reaction is cyclohexane; the catalyst is methanesulfonic acid; the amount of the catalyst is 0.15 to 0.2% wt of the total amount of EO3TMP and acrylic acid; and the temperature of the esterification reaction is 70 to 90°C.