A process for the preparation of trimethylolpropane polyoxyethylene ether

Abstract

The application provides a preparation method of trimethylolpropane polyoxyethylene ether, comprising the following steps: carrying out a polymerization reaction on trimethylolpropane, SSZ-13 molecular sieve and ethylene oxide to obtain the trimethylolpropane polyoxyethylene ether. The application adopts SSZ-13 molecular sieve catalyst as a catalyst, the SSZ-13 molecular sieve has a chabazite (CHA) structure, AlO4 and SiO4 tetrahedrons are connected head to tail through oxygen atoms, and are orderly arranged into ellipsoid cages with an eight-membered ring structure and a three-dimensional cross channel structure, the SSZ-13 molecular sieve has good hydrothermal stability, more surface proton acid centers and exchangeable cations, has excellent catalytic characteristics, the prepared trimethylolpropane polyoxyethylene ether has less than 1000 ppm of trimethylolpropane raw material residues, and color (Pt-Co) is less than or equal to 20.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a method for preparing trimethylolpropane polyoxyethylene ether. Background Technology

[0002] Trimethylolpropane polyoxyethylene ether (TMA) is a polyether polyol synthesized by polymerizing trimethylolpropane with ethylene oxide under the action of a catalyst. It is an important intermediate for UV curing and is mainly used as a raw material for synthesizing methacrylate or acrylate reactive diluents. While possessing low viscosity and high photoactivity, TMA imparts excellent flexibility to the cured film and can improve its shrinkage and irritation. These reactive diluents are widely used in many fields, such as chemical coatings, 3D printing, machinery manufacturing, automotive manufacturing, aerospace, and medical equipment.

[0003] US Patent 4382135 uses KOH as a catalyst to prepare polyether polyols, but the anionic catalytic activity of epoxides is low, and chain transfer reactions to monomers occur. During the polymerization process, a rapid proton exchange reaction occurs between the initiator and the anionic growing chain, reducing the degree of polymerization and broadening the relative molecular mass distribution. Furthermore, the product obtained by this method has a high residual initiator content. Chinese Patent CN106084199 uses a ternary catalyst composed of KOH, 18-crown ether-6, and an alkaline earth metal. This catalyst solves the problems of low molecular weight and broad molecular weight distribution, and the preparation process is simple. However, the product obtained by this method still has a high residual initiator content. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for preparing trimethylolpropane polyoxyethylene ether, wherein the trimethylolpropane polyoxyethylene ether obtained by the preparation method provided by this invention has low raw material residue and high purity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for preparing trimethylolpropane polyoxyethylene ether, comprising the following steps:

[0007] Trimethylolpropane, SSZ-13 molecular sieve, and ethylene oxide are polymerized to obtain the trimethylolpropane polyoxyethylene ether.

[0008] Preferably, the molar ratio of trimethylolpropane to ethylene oxide is 1:3 to 50.

[0009] Preferably, the particle size of the SSZ-13 molecular sieve is 0.2 to 10 μm.

[0010] Preferably, the mass of the SSZ-13 molecular sieve is 0.1 to 1‰ of the total mass of trimethylolpropane and ethylene oxide.

[0011] Preferably, the polymerization reaction is carried out at a temperature of 120–160°C, a pressure of -0.05–0.50 MPa, and a time of 1–7 h.

[0012] Preferably, the polymerization reaction further includes: mixing trimethylolpropane and SSZ-13 molecular sieve, and then introducing ethylene oxide.

[0013] Preferably, the introduction of ethylene oxide is carried out in an inert gas environment.

[0014] Preferably, the polymerization reaction further includes the recovery of SSZ-13 molecular sieve; the recovery of SSZ-13 molecular sieve preferably includes sequential filtration and washing; the filtration temperature is 30-110°C.

[0015] This invention provides a method for preparing trimethylolpropane polyoxyethylene ether, comprising the following steps: polymerizing trimethylolpropane, SSZ-13 molecular sieve, and ethylene oxide to obtain the trimethylolpropane polyoxyethylene ether. This invention uses SSZ-13 molecular sieve catalyst as the catalyst. SSZ-13 molecular sieve has a chalcogenide (CHA) structure, consisting of AlO4 and SiO4 tetrahedra connected end-to-end by oxygen atoms, arranged in an orderly manner into an ellipsoidal cage with an eight-membered ring structure and a three-dimensional intersecting channel structure. It exhibits good hydrothermal stability, numerous surface proton acid centers, and exchangeable Al atoms. 3+ The cation has excellent catalytic properties, and the resulting trimethylolpropane polyoxyethylene ether has a trimethylolpropane raw material residue of less than 1000 ppm and a color (Pt-Co) ≤20.

[0016] Meanwhile, SSZ-13 molecular sieve catalysts are characterized by convenient post-processing, simple separation, and reusability. Detailed Implementation

[0017] This invention provides a method for preparing trimethylolpropane polyoxyethylene ether, comprising the following steps:

[0018] Trimethylolpropane, SSZ-13 molecular sieve, and ethylene oxide are polymerized to obtain the trimethylolpropane polyoxyethylene ether.

[0019] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0020] In this invention, the molar ratio of trimethylolpropane to ethylene oxide is preferably 1:3 to 50, more preferably 1:5 to 42.4, and most preferably 1:5 to 19.7.

[0021] In this invention, the particle size of the SSZ-13 molecular sieve is preferably 0.2-10 μm, more preferably 0.5-8 μm, and most preferably 1-5 μm.

[0022] In this invention, the mass of the SSZ-13 molecular sieve is preferably 0.1 to 1‰ of the total mass of trimethylolpropane and ethylene oxide, more preferably 0.2 to 0.8‰, and most preferably 0.4 to 0.6‰.

[0023] In this invention, the temperature of the polymerization reaction is preferably 120-160°C, more preferably 130-150°C, and most preferably 135-145°C; the pressure is preferably -0.05-0.50 MPa, more preferably -0.03-0.40 MPa, and most preferably -0.02-0.30 MPa; and the time is preferably 1-7 h, more preferably 2-5 h, and most preferably 3-4 h.

[0024] In this invention, the equation for the polymerization reaction is:

[0025]

[0026] In this invention, the polymerization reaction preferably includes: mixing trimethylolpropane and SSZ-13 molecular sieve, and then introducing ethylene oxide; the mixing process preferably includes heating and melting the trimethylolpropane; the heating and melting temperature is preferably 80-160°C, more preferably 90-150°C, and most preferably 100-120°C.

[0027] In this invention, the introduction of ethylene oxide is preferably carried out in an inert gas environment; the inert gas is preferably nitrogen or argon, more preferably nitrogen.

[0028] In this invention, the polymerization reaction is followed by the recovery of SSZ-13 molecular sieve; the recovery of SSZ-13 molecular sieve preferably includes sequential filtration and washing; the method of recovering SSZ-13 molecular sieve is preferably filtration; the filtration temperature is preferably 30-110°C, more preferably 50-90°C, and most preferably 60-80°C; the washing solvent is preferably water; the number of washing cycles is preferably 1-5 times, more preferably 2-5 times, and most preferably 4-5 times.

[0029] In this invention, the content of trimethylolpropane in trimethylolpropane polyoxyethylene ether is preferably ≤1000ppm, more preferably 100-700ppm, and most preferably 300-500ppm; the color is preferably ≤20, more preferably 3-15, and most preferably 5-10; the number average molecular weight is preferably 200-3000, more preferably 250-2500, and most preferably 300-2000; the hydroxyl value is preferably 55-850mgKOH / g, more preferably 70-700mgKOH / g, and most preferably 80-561mgKOH / g.

[0030] This invention uses SSZ-13 molecular sieve catalyst as the catalyst. SSZ-13 molecular sieve has a chalcogenide (CHA) structure, in which AlO4 and SiO4 tetrahedra are connected end to end by oxygen atoms and arranged in an orderly manner to form an ellipsoidal cage with an eight-membered ring structure and a three-dimensional cross-channel structure. It has good hydrothermal stability, a large number of surface proton acid centers and exchangeable cations, and has excellent catalytic properties. The resulting trimethylolpropane polyoxyethylene ether has a trimethylolpropane raw material residue of less than 1000 ppm and a color (Pt-Co) ≤20.

[0031] Meanwhile, SSZ-13 molecular sieve catalysts are characterized by convenient post-processing, simple separation, and reusability.

[0032] To further illustrate the present invention, the preparation method of the trimethylolpropane polyoxyethylene ether provided by the present invention will be described in detail below with reference to the embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0035] 800g of trimethylolpropane and 0.423g of SSZ-13 molecular sieve were weighed and mixed in a reactor. After evacuation, nitrogen was introduced into the reactor three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 140±2℃. The pressure inside the reactor was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure inside the reactor no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. The product yielded trimethylolpropane polyoxyethylene ether. Gas chromatography analysis showed that the trimethylolpropane content was 345 ppm, the product color (Pt-Co) was 8, the number-average molecular weight was 345, and the hydroxyl value determined by chemical method was 487.9 mg KOH / g.

[0036] Example 2

[0037] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0038] 800g of trimethylolpropane and 0.845g of SSZ-13 molecular sieve were weighed and mixed in a reactor. After evacuation, nitrogen was introduced into the reactor three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 140±2℃. The pressure inside the reactor was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure inside the reactor no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. The product yielded trimethylolpropane polyoxyethylene ether. Gas chromatography analysis showed that the trimethylolpropane content was 366 ppm; the product color (Pt-Co) was 8; the number-average molecular weight was 354; and the hydroxyl value determined by chemical method was 475.5 mg KOH / g.

[0039] Example 3

[0040] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0041] 800g of trimethylolpropane and 1.268g of SSZ-13 molecular sieve were weighed and mixed, then added to a reaction vessel. After evacuation, nitrogen was introduced into the reaction vessel three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 140±2℃. The pressure inside the reaction vessel was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure in the system inside the reaction vessel no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. After discharge, trimethylolpropane polyoxyethylene ether was obtained. Gas chromatography analysis showed that the trimethylolpropane content was 460 ppm; the product color (Pt-Co) was 13; the number-average molecular weight was 355; and the hydroxyl value determined by chemical method was 474.1 mg KOH / g.

[0042] Example 4

[0043] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0044] 800g of trimethylolpropane and 0.845g of SSZ-13 molecular sieve were weighed and mixed, then added to a reaction vessel. After evacuation, nitrogen was introduced into the reaction vessel three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, controlling the reaction temperature at 130±2℃ and the pressure inside the reaction vessel ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure inside the reaction vessel no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. The product yielded trimethylolpropane polyoxyethylene ether. Gas chromatography analysis showed that the trimethylolpropane content was 620 ppm; the product color (Pt-Co) was 7; the number-average molecular weight was 340; and the hydroxyl value determined by chemical method was 495.2 mg KOH / g.

[0045] Example 5

[0046] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0047] 800g of trimethylolpropane and 0.845g of SSZ-13 molecular sieve were weighed and mixed, then added to a reaction vessel. After evacuation, nitrogen was introduced into the reaction vessel three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 150±2℃. The pressure inside the reaction vessel was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure in the system inside the reaction vessel no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. After discharge, trimethylolpropane polyoxyethylene ether was obtained. Gas chromatography analysis showed that the trimethylolpropane content was 324 ppm; the product color (Pt-Co) was 15; the number-average molecular weight was 355; and the hydroxyl value determined by chemical method was 474.7 mg KOH / g.

[0048] Comparative Example 1

[0049] This comparative example demonstrates the synthesis of a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0050] 800g of trimethylolpropane and 0.845g of sodium hydroxide were weighed, mixed, and added to a reaction vessel. After evacuation, nitrogen was introduced into the reaction vessel three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1313g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 140±2℃. The pressure inside the reaction vessel was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure in the system inside the reaction vessel no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃, and the product was degassed under vacuum. After discharge, trimethylolpropane polyoxyethylene ether was obtained. Gas chromatography analysis showed that the trimethylolpropane content was 661 ppm; the product color (Pt-Co) was 34; the number-average molecular weight was 353; and the hydroxyl value determined by chemical method was 476.9 mg KOH / g.

[0051] Comparative Example 2

[0052] This comparative example demonstrates the synthesis of a trimethylolpropane polyoxyethylene ether product with a number-average molecular weight of 354. The specific steps are as follows:

[0053] Weigh 800g of trimethylolpropane and 0.845g of potassium hydroxide, mix them, and add them to a reaction vessel. After evacuating the vessel, purge with nitrogen three times. Under a vacuum of ≥-0.098 MPa, heat to 110℃ to completely melt the trimethylolpropane. Continuously introduce 1313g of ethylene oxide, controlling the reaction temperature at 140±2℃ and the pressure inside the reaction vessel ≤0.30 MPa. After the addition is complete, maintain the temperature and continue the reaction. After 4 hours, the pressure inside the reaction vessel no longer decreases, indicating the reaction is complete. Cool to 100℃ and degas under vacuum. After discharging, trimethylolpropane polyoxyethylene ether is obtained. Gas chromatography analysis of the product shows a trimethylolpropane content of 681 ppm; a product color (Pt-Co) of 26; a number-average molecular weight of 354; and a hydroxyl value of 475.1 mgKOH / g determined by chemical methods. The preparation conditions and product performance parameters of Examples 1-5 and Comparative Examples 1-2 are shown in Table 1.

[0054] Table 1. Preparation conditions and product performance parameters of Examples 1-5 and Comparative Examples 1-2

[0055]

[0056]

[0057] Note: In the table above, A represents the catalyst SSZ-13 molecular sieve, B represents the catalyst NaOH, and C represents the catalyst KOH.

[0058] A comparison of Examples 1 to 3 in Table 1 shows that when the reaction temperature and catalyst type remain unchanged, if the catalyst dosage is less than 0.4‰, the reaction will be incomplete due to insufficient catalyst, resulting in a smaller molecular weight of the product. If the catalyst dosage is higher than 0.4‰, the trimethylolpropane content of the product will be higher and the color will be darker.

[0059] A comparison of Examples 2, 4, and 5 in Table 1 shows that, with the catalyst type and amount remaining constant, a reaction temperature of 140±2℃ is optimal. If the reaction temperature is below 140℃, the reaction is incomplete, resulting in the product's molecular weight not reaching the theoretical value of 349, while the trimethylolpropane content is higher. If the reaction temperature is above 140℃, although the molecular weight and trimethylolpropane content are both better, the product color is darker.

[0060] Compared with Example 2, Comparative Examples 1 and 2, under the same reaction temperature and catalyst dosage, although the number average molecular weight is close to the design amount, the content of trimethylolpropane in the raw material is higher and the product color is darker. It can be seen that the catalyst used in this invention has certain advantages.

[0061] Example 6

[0062] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number average molecular weight of 1000. The specific steps are as follows:

[0063] 196g of trimethylolpropane and 0.584g of SSZ-13 molecular sieve were weighed and mixed, then added to a reaction vessel. After evacuation, nitrogen was introduced into the reaction vessel three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1264g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 130±2℃. The pressure inside the reaction vessel was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure inside the reaction vessel no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. The product yielded trimethylolpropane polyoxyethylene ether. Gas chromatography analysis showed that the trimethylolpropane content was 135 ppm; the product color (Pt-Co) was 5; the number-average molecular weight was 1001; and the hydroxyl value determined by chemical method was 168.7 mg KOH / g.

[0064] Example 7

[0065] This embodiment designs and synthesizes a trimethylolpropane polyoxyethylene ether product with a number average molecular weight of 2000. The specific steps are as follows:

[0066] 134g of trimethylolpropane and 0.800g of SSZ-13 molecular sieve were weighed and mixed in a reactor. After evacuation, nitrogen was introduced into the reactor three times. Under a vacuum of ≥-0.098 MPa, the temperature was raised to 110℃ to completely melt the trimethylolpropane. 1866g of ethylene oxide was continuously introduced, and the reaction temperature was controlled at 130±2℃. The pressure inside the reactor was ≤0.30 MPa. After the addition was complete, the temperature was maintained and the reaction continued. After 4 hours, the pressure inside the reactor no longer decreased, indicating the end of the reaction. The temperature was lowered to 100℃ and degassed under vacuum. The product yielded trimethylolpropane polyoxyethylene ether. Gas chromatography analysis showed that the trimethylolpropane content was 166 ppm; the product color (Pt-Co) was 7; the number-average molecular weight was 2001; and the hydroxyl value determined by chemical method was 84.3 mg KOH / g.

[0067] Example 8

[0068] This embodiment aims to examine the reproducibility of the catalyst, and the specific steps are as follows:

[0069] Weigh 800g of trimethylolpropane and 0.845g of SSZ-13 molecular sieve, mix them, and put them into a reactor. After evacuating the reactor, replace the nitrogen gas with nitrogen gas three times. Under a vacuum of ≥-0.098Mpa, heat the reactor to 110℃ to completely melt the trimethylolpropane. Continuously introduce 1313g of ethylene oxide, control the reaction temperature at 140±2℃, and maintain the pressure inside the reactor at ≤0.30Mpa. After the addition is complete, maintain the temperature and continue the reaction. After 4 hours, the pressure inside the reactor no longer decreases, and the reaction ends. Cool the reactor to 100℃ and degas under vacuum. After discharging, trimethylolpropane polyoxyethylene ether is obtained. Filter the obtained trimethylolpropane polyoxyethylene ether at a temperature controlled at 70±5℃. After filtration, wash the filter residue with water 4-5 times to obtain the recovered catalyst. The above preparation process was repeated using the SSZ-13 molecular sieve recovered through filtration. If the recovered catalyst mass was ≤0.75g, additional catalyst was added to bring the mass to 0.845g. The product performance parameters of the SSZ-13 molecular sieve under the condition of repeated use are shown in Table 2.

[0070] Table 2. Performance parameters of SSZ-13 molecular sieve under reusable conditions.

[0071]

[0072]

[0073] As shown in Table 2, the SSZ-13 molecular sieve catalyst used in this invention can still produce trimethylolpropane polyoxyethylene ether products with a trimethylolpropane residue of ≤1000ppm, a color of ≤20, and a hydroxyl value of approximately 477mgKOH / g after being reused 40 times.

[0074] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A process for the preparation of trimethylolpropane polyoxyethylene ether, characterized in that, The method comprises the following steps: The trimethylolpropane, SSZ-13 molecular sieve and ethylene oxide are subjected to a polymerization reaction to obtain the trimethylolpropane polyoxyethylene ether; the mass of the SSZ-13 molecular sieve is 0.1-1 ‰ of the total mass of the trimethylolpropane and the ethylene oxide; the polymerization reaction is carried out at a temperature of 120-160 ℃, a pressure of-0.05-0.50 MPa and for 1-7 h.

2. The production method according to claim 1, characterized by, The molar ratio of the trimethylolpropane to the ethylene oxide is 1:3-50.

3. The production method according to claim 1, characterized by, The particle size of the SSZ-13 molecular sieve is 0.2-10 μm.

4. The preparation method according to claim 1, characterized in that, Before the polymerization reaction, the trimethylolpropane and the SSZ-13 molecular sieve are mixed, and then the ethylene oxide is introduced.

5. The production method according to claim 4, characterized by, The introduction of the ethylene oxide is carried out in an inert gas environment.

6. The method of claim 1, wherein, After the polymerization reaction, the SSZ-13 molecular sieve is recovered; the recovery of the SSZ-13 molecular sieve comprises filtration and washing which are carried out in sequence; the temperature of the filtration is 30-110 ℃.

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