A method for synthesizing a bismethyl-terminated polyether

Abstract

The application belongs to the technical field of polyether synthesis, and discloses a synthesis method of dimethyl-terminated polyether. The synthesis method is as follows: methanol polyether is mixed with an alcohol salt reagent, degassed after being heated, then an adsorbent and a crystal seed are added, chloromethane is added for curing reaction, and finally secondary degassing is performed to obtain dimethyl-terminated polyether; wherein the crystal seed is selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate and potassium dihydrogen phosphate; the adding amount of the crystal seed is 0.1% to 2% of the mass of the methanol polyether. The synthesis method combines synthesis and refining processes, controls the adding time of the adsorbent and the crystal, and uses the adsorbent and the crystal together, so that the total process time can be greatly shortened, the preparation efficiency can be improved, the production cost can be reduced, the quality of the dimethyl-terminated polyether can be improved, the prepared dimethyl-terminated polyether product has light color, low hydroxyl value, low potassium and sodium ion content, and high termination rate.

Description

Technical Field

[0001] This invention belongs to the field of polyether synthesis technology, specifically relating to a method for synthesizing dimethyl-terminated polyether. Background Technology

[0002] Dimethyl-terminated polyether (DMPE) is a special type of polyether. The hydroxyl groups at both ends of its molecular chain are replaced by methyl groups, and the molecular chain contains only -COC, -CC, and -CH, resulting in high chemical stability. In the field of low-foaming cleaning agents, it effectively reduces foam generation and improves cleaning efficiency. DMPE can also be used as an oiling agent to improve the lubrication and processing properties of synthetic fibers, while reducing static electricity and coking. DMPE can also be used as a finishing agent to impart softness, smoothness, and water resistance to fabrics, improving textile quality. In the production of polyurethane foam, DMPE can also be used as a stabilizer, helping to adjust foam pore size, stabilize foam structure, and improve foam uniformity and durability. Due to its good skin compatibility and stability, DMPE can also be used as an additive in cosmetics to enhance the user experience and effectiveness. In the coatings industry, DMPE can also be used as an additive to significantly improve the flowability and application properties of coatings, while also enhancing their weather resistance and corrosion resistance. Dimethyl-terminated polyethers can also be used in many fields such as solid electrolytes, lubricants, and ink additives, leveraging their unique chemical and physical properties. Their applications are extremely wide-ranging and they have broad market prospects.

[0003] Currently, the synthesis and purification of dimethyl-terminated polyethers involve the following processes: Firstly, traditional purification processes mostly involve dissolving and adsorbing the crude product, followed by dehydration, crystallization, and filtration to obtain the finished product. For example, Huntsman Corporation dissolves neutralized and dehydrated crude polyether in water, dehydrates and recrystallizes it again, and finally filters it to obtain the product; (Zhejiang University Yang Zheng et al., Research and Application Technology of Novel Polyether Post-treatment Agents [J]. Polyurethane Industry,) (1995(2):23-26) A self-made polyether post-treatment agent was used for adsorption. Metal salts in polyethers, then using a first-bandThe process involves several steps: 1) Water filtration to remove crystalline salts, followed by dehydration to obtain the product. All of these processes involve adding water to the crude product, then dehydrating, recrystallizing the metal salts, and then filtering to remove them. This dehydration process is time-consuming. 2) Ion exchange resin method: The crude polyether is passed through an ion exchange resin bed with a polar organic solvent, followed by dehydration and solvent removal. However, this method is complex and costly. 3) Using monoalkyl polyether as raw material, a dialkyl-terminated polyether is synthesized by etherification and end-capping under the action of an etherifying agent, followed by water washing to obtain dialkyl-terminated polyether. This method requires three water washes, generating a significant amount of wastewater and is also time-consuming. 4) Using polyether as raw material, an alkoxide reagent (potassium hydroxide or sodium hydroxide, or a mixture thereof) is added for reaction. The water generated is removed, and then chloromethane gas is introduced to continue the reaction. The resulting crude polyether is then mixed with 1%-5% distilled water, sodium chloride, or potassium chloride under stirring to form coarse crystals. After filtration, a refined product is obtained. This method involves adding a small amount of water, but without removing it, resulting in a high moisture content and excessively high potassium and sodium ion levels in the product, which negatively impacts downstream applications.

[0004] Currently, the synthesis and purification processes for dimethyl-terminated polyethers are mostly complex and time-consuming, resulting in long overall production times, low synthesis efficiency, and high post-processing costs. Therefore, it is essential to develop a process that enables rapid purification or post-processing, simplifying procedures, shortening post-processing time, and ultimately improving synthesis efficiency and reducing production costs. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for synthesizing dimethyl-terminated polyethers. The synthesis method provided by the present invention can shorten post-processing time, improve preparation efficiency, and reduce production costs.

[0006] This invention provides a method for synthesizing dimethyl-terminated polyether.

[0007] Specifically, a method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0008] Methanol polyether was mixed with an alkoxide reagent, heated and degassed, then an adsorbent and seed crystals were added, followed by the addition of chloromethane for ripening reaction, and finally degassed twice to obtain dimethyl-terminated polyether.

[0009] The seed crystals are selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate; the amount of seed crystals added is 0.1%-2% of the mass of the methanol polyether.

[0010] Preferably, the amount of seed crystals added is 0.1%-1.5% of the mass of the methanol polyether.

[0011] Preferably, the peak molecular weight of the methanol polyether is 1000-2000.

[0012] Preferably, the alkoxide reagent is selected from at least one of sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide.

[0013] Preferably, the heating and degassing process involves heating the reaction system to 100-130°C and degassing it under a vacuum of -0.099 MPa for 2-5 hours. This process removes the methanol or water generated in the reaction, avoiding any impact on subsequent reactions.

[0014] Preferably, the adsorbent includes at least one of aluminum silicate, magnesium silicate, and magnesium aluminum silicate.

[0015] Preferably, the amount of adsorbent added is 0.5%-5% of the mass of the methanol polyether; more preferably, the amount of adsorbent added is 0.5%-3% of the mass of the methanol polyether.

[0016] Preferably, a cooling process is included before adding the adsorbent and the seed crystals, wherein the cooling process is to cool to 50-70°C.

[0017] Preferably, the chloromethane is added dropwise at a rate of 0.1-1.5 g / min and at a temperature of 50-70°C.

[0018] Preferably, the molar ratio of the methanol polyether to the alkoxide reagent and the chloromethane is 1.0:(1.1-1.8):(1.1-1.8).

[0019] More preferably, the molar ratio of the methanol polyether to the alkoxide reagent and the chloromethane is 1.0:(1.1-1.5):(1.1-1.5).

[0020] Preferably, the ripening reaction temperature is 50-70℃ and the ripening reaction time is 0.5-5h.

[0021] Preferably, the secondary degassing process is carried out at 80-110℃ under a vacuum of -0.099 MPa for 0.5-2 hours.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) The method for synthesizing dimethyl-terminated polyether provided by this invention involves first reacting methanol polyether with an alkoxide reagent to generate potassium or sodium polyether. Then, before adding chloromethane for further reaction, an adsorbent and seed crystals are added to the reaction system. This allows the potassium chloride and sodium chloride generated during the reaction of the potassium or sodium polyether with chloromethane to form large salt particles in a timely manner under the action of the adsorbent and seed crystals, which are then removed by filtration. This method combines synthesis and purification processes. By controlling the timing of the addition of the adsorbent and crystals and using them in combination, it not only significantly shortens the total process time, improves preparation efficiency, and reduces production costs, but also improves the quality of the dimethyl-terminated polyether. The resulting dimethyl-terminated polyether product has a light color, low hydroxyl value, low potassium and sodium ion (ppm) content, high end-capping rate, and excellent application performance.

[0024] (2) The synthesis method provided by the present invention can generate the target product dimethyl-terminated polyether while making potassium chloride and sodium chloride form salt particles that are larger and easier to filter. Only simple filtration is needed to achieve the purification effect. It can simplify the processing steps, significantly shorten the post-processing time, and quickly obtain high-quality dimethyl-terminated polyether. Detailed Implementation

[0025] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0026] Unless otherwise specified, the raw materials, reagents or apparatus used in the following examples and comparative examples are available from conventional commercial sources or can be obtained by existing known methods.

[0027] Example 1

[0028] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0029] 1000g of methanol polyether (molecular weight 1000) and 44g of sodium hydroxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 130℃ and maintained at this temperature for degassing for 3 hours. After degassing, the temperature was cooled to 60℃. 5g of magnesium silicate and 1g of seed disodium hydrogen phosphate were added. Then, 75.7g of chloromethane was added dropwise over 3 hours. After the addition was completed, the mixture was aged at 50℃ for 3 hours. After aging, the mixture was stirred and heated to 90℃, degassed under a vacuum of -0.099 MPa, and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0030] Example 2

[0031] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0032] 1000g of methanol polyether (molecular weight 1300) and 51.7g of potassium hydroxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 120℃ and maintained at this temperature for degassing for 4 hours. After degassing, the temperature was cooled to 60℃. 20g of aluminum silicate and 3g of seed potassium dihydrogen phosphate were added. Then, 54.4g of chloromethane was added dropwise over 2 hours. After the addition was completed, the mixture was aged at 60℃ for 2 hours. After aging, the mixture was stirred and heated to 80℃, degassed under a vacuum of -0.099 MPa, and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0033] Example 3

[0034] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0035] 1000g of methanol polyether (molecular weight 1600) and 47.3g of sodium methoxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 110℃ and maintained at this temperature for degassing for 2 hours. After degassing, the temperature was cooled to 60℃. 40g of magnesium aluminum silicate and 8g of seed sodium dihydrogen phosphate were added. Then, 37.9g ​​of chloromethane was added dropwise over 2 hours. After the addition was completed, the mixture was aged at 65℃ for 2 hours. After aging, the mixture was stirred and heated to 110℃, degassed under a vacuum of -0.099 MPa, and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0036] Example 4

[0037] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0038] 1000g of methanol polyether (molecular weight 2000) and 52.5g of potassium methoxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 100℃ and maintained at this temperature for degassing for 5 hours. After degassing, the temperature was cooled to 60℃. 50g of magnesium aluminum silicate and 10g of seed dipotassium hydrogen phosphate were added. Then, 27.8g of chloromethane was added dropwise over 1 hour. After the addition was completed, the mixture was aged at 70℃ for 1 hour. After aging, the mixture was stirred and heated to 100℃, degassed under a vacuum of -0.099 MPa, and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0039] The process parameters for Examples 1-4 are shown in Table 1.

[0040] Table 1

[0041]

[0042] Note: The feed ratio is the molar ratio of methanol polyether to alkali and chloromethane.

[0043] Comparative Example 1

[0044] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0045] 1000g of methanol polyether (molecular weight 1000) and 44g of sodium hydroxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 130℃ and maintained at this temperature for degassing for 3 hours. After degassing, the temperature was cooled to 60℃. 5g of magnesium silicate was added, followed by the dropwise addition of 75.7g of chloromethane over 3 hours. After the dropwise addition was completed, the mixture was aged at 50℃ for 3 hours. After aging, the mixture was stirred and heated to 90℃, then degassed under a vacuum of -0.099 MPa for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0046] Comparative Example 2

[0047] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0048] Add 1000g of methanol polyether (molecular weight 1300) and 51.7g of potassium hydroxide to a glass reactor, and place... After nitrogen treatment three times, the temperature was slowly raised to 120℃ and held at this temperature for degassing for 4 hours. After degassing, the temperature was cooled to 60℃. 20g of aluminum silicate was added, followed by the dropwise addition of 54.4g of chloromethane over 2 hours. After the dropwise addition was completed, the mixture was aged at 60℃ for 2 hours. After aging, the mixture was stirred and heated to 80℃, then degassed under a vacuum of -0.099 MPa for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0049] Comparative Example 3

[0050] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0051] 1000g of methanol polyether (molecular weight 1600) and 47.3g of sodium methoxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 110℃ and maintained at this temperature for degassing for 2 hours. After degassing, the temperature was cooled to 60℃. 40g of magnesium aluminum silicate was added, followed by the dropwise addition of 37.9g ​​of chloromethane over 2 hours. After the dropwise addition was completed, the mixture was aged at 65℃ for 2 hours. After aging, the mixture was stirred and heated to 110℃, degassed under a vacuum of -0.099 MPa, and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0052] Comparative Example 4

[0053] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0054] 1000g of methanol polyether (molecular weight 2000) and 52.5g of potassium methoxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 100℃ and maintained at this temperature for degassing for 5 hours. After degassing, the temperature was cooled to 60℃. 50g of magnesium aluminum silicate was added, followed by the dropwise addition of 27.8g of chloromethane over 1 hour. After the dropwise addition was completed, the mixture was aged at 70℃ for 1 hour. After aging, the mixture was stirred and heated to 100℃, then degassed under a vacuum of -0.099 MPa and maintained at this temperature for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0055] Comparative Example 5

[0056] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0057] 1000g of methanol polyether (molecular weight 1000) and 44g of sodium hydroxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 130℃ and maintained at this temperature for degassing for 3 hours. After degassing, the temperature was cooled to 60℃. Then, 75.7g of chloromethane was added dropwise over 3 hours. After the addition was complete, the mixture was aged at 50℃ for 3 hours. After aging, 100g of deionized water was added, and 1g of phosphoric acid was added to adjust the pH to 6.0. Then, 5g of magnesium silicate and 1g of seed disodium hydrogen phosphate were added. After adsorption for 30 minutes, the mixture was slowly dehydrated, heated to 90℃, and degassed under a vacuum of -0.099 MPa for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0058] Comparative Example 6

[0059] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0060] A method for synthesizing a dimethyl-terminated polyether includes the following steps:

[0061] 1000g of methanol polyether (molecular weight 1300) and 51.7g of potassium hydroxide were added to a glass reactor. After being exposed to nitrogen three times, the temperature was slowly raised to 120℃ and maintained at this temperature for degassing for 4 hours. After degassing, the temperature was cooled to 60℃. Then, 54.4g of chloromethane was added dropwise over 2 hours. After the addition was completed, the mixture was aged at 60℃ for 2 hours. After aging, 150g of deionized water and 2.0g of phosphoric acid were added to adjust the pH to 5.5. Then, 20g of aluminum silicate and 3g of seed potassium dihydrogen phosphate were added. After adsorption for 30 minutes, the mixture was slowly dehydrated, heated to 80℃, and degassed under a vacuum of -0.099 MPa for 1 hour. The mixture was then filtered to obtain the dimethyl-terminated polyether product.

[0062] The process parameters for Comparative Examples 1-6 are shown in Table 2.

[0063] Table 2

[0064]

[0065]

[0066] Product performance testing

[0067] The color, hydroxyl value, capping rate, and potassium and sodium ion content of the dimethyl-terminated polyethers prepared in the examples and comparative examples were tested, and the process time of each example and comparative example synthesis process was statistically analyzed.

[0068] The color testing method refers to GB / T9282.1-2008; the hydroxyl value testing method refers to GB / T7383-2007; the end-capping rate = (hydroxyl value of polyether before end-capping - hydroxyl value of polyether after end-capping) / hydroxyl value of polyether before end-capping × 100%.

[0069] The test results are shown in Tables 3 and 4.

[0070] Table 3

[0071]

[0072]

[0073] Table 4

[0074] As shown in Tables 3 and 4, the synthesis method provided in this invention significantly shortens the process time from 15-19 hours to 10-12 hours, a reduction of 3-7 hours. Furthermore, the dimethyl-terminated polyether prepared by this invention has less residual potassium and sodium ions and a higher termination rate. Therefore, the optimization of the synthesis process by this invention, especially the control of the timing of adsorbent and crystal addition and their combined use, can significantly shorten the synthesis time, improve preparation efficiency, reduce production costs, and enhance the quality of the dimethyl-terminated polyether.

[0075] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for synthesizing a dimethyl-terminated polyether, characterized in that, Includes the following steps: Methanol polyether was mixed with an alkoxide reagent, heated and degassed, then an adsorbent and seed crystals were added, followed by the addition of chloromethane for ripening reaction, and finally degassed twice to obtain dimethyl-terminated polyether. The seed crystals are selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate; the amount of seed crystals added is 0.1%-2% of the mass of the methanol polyether; The adsorbent includes at least one of aluminum silicate, magnesium silicate, and magnesium aluminum silicate. The amount of adsorbent added is 0.5%-5% of the mass of the methanol polyether.

2. The synthesis method according to claim 1, characterized in that, The amount of seed crystals added is 0.1%-1.5% of the mass of the methanol polyether.

3. The synthesis method according to claim 1, characterized in that, The alkoxide reagent is selected from at least one of sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide.

4. The synthesis method according to any one of claims 1-3, characterized in that, The chloromethane is added dropwise at a rate of 0.1-1.5 g / min and at a temperature of 50-70°C.

5. The synthesis method according to any one of claims 1-3, characterized in that, The molar ratio of the methanol polyether to the alkoxide reagent and the chloromethane is 1.0:(1.1-1.8):(1.1-1.8).

6. The synthesis method according to claim 5, characterized in that, The molar ratio of the methanol polyether to the alkoxide reagent and the chloromethane is 1.0:(1.1-1.5):(1.1-1.5).

7. The synthesis method according to any one of claims 1-3, characterized in that, The ripening reaction is carried out at a temperature of 50-70°C for 0.5-5 hours.

8. The synthesis method according to claim 7, characterized in that, The secondary degassing process is carried out at 80-110℃ and under a vacuum of -0.099Mpa for 0.5-2 hours.

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