Synthesis method of dimethyl-terminated polyether

Abstract

The invention belongs to the technical field of polyether synthesis, and discloses a synthesis method of dimethyl-terminated polyether. The synthesis method comprises the following steps: mixing methanol polyether with an alkoxide reagent, heating and degassing, then adding an adsorbent and a seed crystal, then adding chloromethane to carry out a curing reaction, and finally carrying out secondary degassing to prepare the dimethyl-terminated polyether, wherein the seed crystal is selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium phosphate and potassium dihydrogen phosphate; the adding amount of the seed crystal is 0.1%-2% of the mass of the methanol polyether. According to the synthesis method provided by the invention, a synthesis process and a refining process are combined, and the total process time can be greatly shortened, the preparation efficiency can be improved and the production cost can be reduced by controlling the adding time of the adsorbent and the crystal and cooperatively using the adsorbent and the crystal; and moreover, the quality of the dimethyl-terminated polyether can be improved, and the prepared dimethyl-terminated polyether finished product is light in color, low in hydroxyl value, low in potassium and sodium ion content and high in termination rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyether synthesis, and particularly relates to a method for synthesizing dimethyl-capped polyether. Background Art

[0002] Dimethyl-capped polyether is a special polyether. The hydroxyl groups at both ends of the molecular chain are replaced by methyl groups, and the molecular chain only contains -C-O-C, -C-C, -C-H, so its chemical stability is high. In the field of low-foam cleaning agents, it can effectively reduce foam generation and improve cleaning efficiency; dimethyl-capped polyether can also be used as an oil agent to improve the lubricating performance and processing performance of chemical fibers, while reducing static electricity and coking phenomena. Dimethyl-capped polyether can also be used as a finishing agent to endow fabrics with softness, smoothness, water resistance and other characteristics, and improve the quality of textiles. In the production process of polyurethane foam, dimethyl-capped polyether can also be used as a stabilizer to help adjust the foam pore size, stabilize the foam structure, and improve the uniformity and durability of the foam. Due to its good skin compatibility and stability, dimethyl-capped polyether can also be used as an additive in cosmetics to enhance the use experience and effect of cosmetics. In the paint industry, dimethyl-capped polyether can also be used as an additive, which can significantly improve the fluidity and construction performance of paints, while enhancing the weather resistance and corrosion resistance of paints. Dimethyl-capped polyether can also be used in multiple fields such as solid electrolytes, lubricants, and ink additives, giving play to its unique chemical and physical property advantages, and its application fields are extremely wide, with broad market prospects.

[0003] At present, there are the following several processes for the synthesis and purification of dimethyl-capped polyether: One is that most traditional purification processes dissolve and adsorb the crude product, and then dehydrate and crystallize it, and filter to obtain the finished product. For example, Huntsman Corporation dissolves the polyether crude product that has been neutralized and dehydrated, dehydrates and recrystallizes it again, and finally filters to obtain the product; Yang Zheng et al. from Zhejiang University (Research and Application Technology of New Polyether Post-treatment Agents [J]. Polyurethane Industry, In 1995(2): 23 - 26), a self - made polyether post - treatment agent was used to adsorb metal salts in the polyether, and then with a leadingWater filtration is carried out to remove crystalline salts, followed by dehydration to obtain the product. In the above processes, crude product is added with water and then dehydrated, and the metal salts are removed by filtration after recrystallization. The dehydration process takes a long time. Second, through the ion exchange resin method, the crude polyether and a polar organic solvent are passed through an ion exchange resin bed together, and then dehydrated and desolvated. However, this method has a relatively complex process and high production costs. Third, using monoalkyl polyether as the raw material, under the action of an etherification reagent, the monoalkyl polyether is subjected to an etherification capping reaction for synthesis, and then washed with water to obtain the dialkyl-capped polyether. This method requires three water washes, generating a large amount of wastewater and a relatively long process time. Fourth, using polyether as the raw material, an alcohol saltification reagent is added for reaction. The alcohol saltification reagent is one or a mixture of potassium hydroxide or sodium hydroxide; the generated water is removed by reaction, and then methyl chloride gas is introduced to continue the reaction; for the obtained crude polyether, 1%-5% distilled water, sodium chloride or potassium chloride is added under stirring conditions to form large crystals, and the refined product can be obtained after filtration. In this method, due to the addition of a small amount of water but without removal, the water content of the product is relatively high, and the potassium and sodium ions of the product are too high, affecting downstream applications.

[0004] Currently, for the synthesis and refining processes of dimethyl-capped polyether, most of them have complex and time-consuming processes, resulting in a long total production process time, low synthesis efficiency, and relatively high post-treatment costs. Therefore, it is very necessary to develop a process that can be quickly refined or post-treated, simplify the treatment process, shorten the post-treatment time, and achieve the purpose of 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 above prior art. For this reason, the present invention proposes a synthesis method of dimethyl-capped polyether. The synthesis method provided by the present invention can shorten the post-treatment time, improve the preparation efficiency, and reduce the production cost.

[0006] The present invention provides a synthesis method of dimethyl-capped polyether.

[0007] Specifically, a synthesis method of dimethyl-capped polyether includes the following steps:

[0008] Mix methanol polyether with an alcohol saltification reagent, heat up to remove gas, then add an adsorbent and crystal seeds, and then add methyl chloride for a ripening reaction, and finally perform secondary degassing to obtain dimethyl-capped polyether;

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

[0010] Preferably, the addition amount of the crystal seeds 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 alcoholate reagent is selected from at least one of sodium hydroxide, potassium hydroxide, sodium methoxide, and potassium methoxide.

[0013] Preferably, the process of heating and degassing is as follows: the reaction system is heated to 100 - 130 °C, and degassed for 2 - 5 h under a vacuum of -0.099 Mpa. This process can remove the methanol or water generated during the reaction and avoid affecting the subsequent reaction.

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

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

[0016] Preferably, before adding the adsorbent and the seed crystal, there is also a cooling process, and the cooling process is to cool to 50 - 70 °C.

[0017] Preferably, the methyl chloride is added dropwise, and the dropping rate is 0.1 - 1.5 g / min; the dropping temperature is 50 - 70 °C.

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

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

[0020] Preferably, the temperature of the aging reaction is 50 - 70 °C, and the time of the aging reaction is 0.5 - 5 h.

[0021] Preferably, the process of secondary degassing is to degas for 0.5 - 2 h at 80 - 110 °C under a vacuum of -0.099 Mpa.

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

[0023] (1) The synthesis method of the dimethyl-capped polyether provided by the present invention first reacts methanol polyether with an alcohol salt-forming reagent to generate potassium polyether or sodium polyether, and then before adding methyl chloride for reaction, an adsorbent and crystal seeds are first added to the reaction system, so that potassium chloride and sodium chloride generated during the reaction of potassium polyether or sodium polyether with methyl chloride can form large-grained salt particles in a timely manner under the action of the adsorbent and crystal seeds, and then are removed by filtration. The synthesis method provided by the present invention combines the synthesis and refining processes into one. By controlling the addition timing of the adsorbent and crystal and their combined use, not only can the total process duration be significantly shortened, the preparation efficiency be improved, and the production cost be reduced; but also the quality of the dimethyl-capped polyether can be improved. The dimethyl-capped polyether product prepared has a light color, a low hydroxyl value, a low content of potassium and sodium ions (ppm), a high capping rate, and excellent application performance.

[0024] (2) The synthesis method provided by the present invention can form salt particles with large particles and easier filtration of potassium chloride and sodium chloride while generating the target product dimethyl-capped polyether, and only simple filtration can achieve the refining effect; it can simplify the treatment process, significantly shorten the post-treatment time, and quickly obtain high-quality dimethyl-capped polyether. Specific embodiments

[0025] In order to make the technical solutions described in the present invention clearer and more understandable to those skilled in the art, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0026] The raw materials, reagents or devices used in the following examples and comparative examples can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0027] Example 1

[0028] A synthesis method of a dimethyl-capped polyether, comprising the following steps:

[0029] Add 1000 g of methanol polyether (molecular weight 1000) and 44 g of sodium hydroxide into a glass reaction kettle. After purging with nitrogen three times, slowly heat up to 130 °C and keep warm and degas for 3 h; after the heat preservation and degassing are completed, cool to 60 °C; add 5 g of magnesium silicate and 1 g of crystal seed disodium hydrogen phosphate; then dropwise add 75.7 g of methyl chloride, and the dropping time is 3 h; after the dropping is completed, keep warm and cure at 50 °C for 3 h. After curing, stir and heat up to 90 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and filter to obtain the dimethyl-capped polyether product.

[0030] Example 2

[0031] A synthesis method of a dimethyl-capped polyether, comprising the following steps:

[0032] Add 1000 g of methanol polyether (molecular weight 1300) and 51.7 g of potassium hydroxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 120 °C and keep warm for degassing for 4 h. After the heat preservation and degassing are completed, cool down to 60 °C. Add 20 g of aluminum silicate and 3 g of seed potassium dihydrogen phosphate. Then, dropwise add 54.4 g of chloromethane over 2 h. After the dropping is completed, keep warm and cure at 60 °C for 2 h. After curing, stir and heat up to 80 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0033] Example 3

[0034] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0035] Add 1000 g of methanol polyether (molecular weight 1600) and 47.3 g of sodium methoxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 110 °C and keep warm for degassing for 2 h. After the heat preservation and degassing are completed, cool down to 60 °C. Add 40 g of magnesium aluminum silicate and 8 g of seed sodium dihydrogen phosphate. Then, dropwise add 37.9 g of chloromethane over 2 h. After the dropping is completed, keep warm and cure at 65 °C for 2 h. After curing, stir and heat up to 110 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0036] Example 4

[0037] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0038] Add 1000 g of methanol polyether (molecular weight 2000) and 52.5 g of potassium methoxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 100 °C and keep warm for degassing for 5 h. After the heat preservation and degassing are completed, cool down to 60 °C. Add 50 g of magnesium aluminum silicate and 10 g of seed dipotassium hydrogen phosphate. Then, dropwise add 27.8 g of chloromethane over 1 h. After the dropping is completed, keep warm and cure at 70 °C for 1 h. After curing, stir and heat up to 100 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0039] The process parameters of 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 base and chloromethane.

[0043] Comparative Example 1

[0044] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0045] Add 1000 g of methanol polyether (molecular weight 1000) and 44 g of sodium hydroxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 130 °C and keep the temperature for 3 h for degassing; after the degassing at constant temperature is completed, cool down to 60 °C; add 5 g of magnesium silicate; then dropwise add 75.7 g of chloromethane over 3 h; after the dropping is completed, keep the temperature at 50 °C for 3 h for aging. After aging, stir and heat up to 90 °C, degas and keep the temperature under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0046] Comparative Example 2

[0047] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0048] 1000 g of methanol polyether (molecular weight 1300) and 51.7 g of potassium hydroxide were added to a glass reaction kettle and placed After purging with nitrogen three times, slowly heat up to 120 °C and keep the temperature for 4 h for degassing; after the degassing at constant temperature is completed, cool down to 60 °C; add 20 g of aluminum silicate; then dropwise add 54.4 g of chloromethane over 2 h; after the dropping is completed, keep the temperature at 60 °C for 2 h for aging. After aging, stir and heat up to 80 °C, degas and keep the temperature under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0049] Comparative Example 3

[0050] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0051] Add 1000 g of methanol polyether (molecular weight 1600) and 47.3 g of sodium methoxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 110 °C and keep the temperature for 2 h for degassing; after the degassing at constant temperature is completed, cool down to 60 °C; add 40 g of magnesium aluminum silicate; then dropwise add 37.9 g of chloromethane over 2 h; after the dropping is completed, keep the temperature at 65 °C for 2 h for aging. After aging, stir and heat up to 110 °C, degas and keep the temperature under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0052] Comparative Example 4

[0053] A method for synthesizing dimethyl-capped polyether, comprising the following steps:

[0054] Add 1000 g of methanol polyether (molecular weight 2000) and 52.5 g of potassium methoxide into a glass reactor. After purging with nitrogen three times, slowly heat up to 100 °C and keep the temperature for 5 h for degassing; after the degassing at constant temperature is completed, cool down to 60 °C; add 50 g of magnesium aluminum silicate; then dropwise add 27.8 g of chloromethane over 1 h; after the dropping is completed, keep the temperature at 70 °C for 1 h for aging. After aging, stir and heat up to 100 °C, degas and keep the temperature under vacuum of -0.099 Mpa for 1 h, and then filter to obtain the finished product of dimethyl-capped polyether.

[0055] Comparative Example 5

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

[0057] Add 1000 g of methanol polyether (molecular weight 1000) and 44 g of sodium hydroxide into a glass reaction kettle. After purging with nitrogen three times, slowly heat up to 130 °C and keep warm for degassing for 3 h; after the degassing at constant temperature is completed, cool down to 60 °C; then dropwise add 75.7 g of chloromethane over 3 h; after the dropping is completed, keep warm and cure at 50 °C for 3 h. After curing, add 100 g of deionized water, add 1 g of phosphoric acid to adjust the pH value to 6.0; then add 5 g of magnesium silicate and 1 g of crystalline sodium hydrogen phosphate, adsorb for 30 min, then slowly dehydrate, heat up to 90 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and filter to obtain the dimethyl-terminated polyether product.

[0058] Comparative Example 6

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

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

[0061] Add 1000 g of methanol polyether (molecular weight 1300) and 51.7 g of potassium hydroxide into a glass reaction kettle. After purging with nitrogen three times, slowly heat up to 120 °C and keep warm for degassing for 4 h; after the degassing at constant temperature is completed, cool down to 60 °C; then dropwise add 54.4 g of chloromethane over 2 h; after the dropping is completed, keep warm and cure at 60 °C for 2 h. After curing, add 150 g of deionized water, add 2.0 g of phosphoric acid to adjust the pH value to 5.5; then add 20 g of aluminum silicate and 3 g of crystalline potassium dihydrogen phosphate, adsorb for 30 min, then slowly dehydrate, heat up to 80 °C, degas and keep warm under vacuum of -0.099 Mpa for 1 h, and filter to obtain the dimethyl-terminated polyether product.

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

[0063] Table 2

[0064]

[0065]

[0066] Product performance test

[0067] Test the color and luster, hydroxyl value, end-blocking rate and potassium and sodium ions of the dimethyl-terminated polyethers prepared in the examples and comparative examples, and count the process duration in the synthesis process of each example and comparative example.

[0068] Among them, the color and luster detection method refers to GB / T9282.1-2008; the hydroxyl value detection method refers to GB / T7383-2007; the capping rate = (the hydroxyl value of the polyether before capping - the hydroxyl value of the polyether after capping) / the hydroxyl value of the polyether before capping × 100%.

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

[0070] Table 3

[0071]

[0072]

[0073] Table 4

[0074] As can be seen from Table 3 and Table 4, the synthesis method provided by the embodiments of the present invention can significantly shorten the process time, which is shortened from 15 - 19 hours to 10 - 12 hours, a reduction of 3 - 7 hours. Moreover, the residual potassium and sodium ions in the double-methyl-capped polyether prepared by the present invention are less, and the capping rate is higher. Thus, it can be seen that the optimization of the synthesis process of the present invention, especially the control of the addition timing of the adsorbent and the crystal and the combined use of the two, can greatly shorten the synthesis time, improve the preparation efficiency, reduce the production cost, and improve the quality of the double-methyl-capped polyether.

[0075] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A method for synthesizing dimethyl-capped polyether, characterized in that, The method includes the following steps: Mix the methanol polyether with an alcohol salt reagent, heat up to remove gas, then add an adsorbent and crystal seeds, then add methyl chloride for aging reaction, and finally perform secondary degassing to obtain a dimethyl-terminated polyether; The crystal seeds are selected from at least one of disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate; the addition amount of the crystal seeds is 0.1%-2% of the mass of the methanol polyether.

2. The synthesis method according to claim 1, wherein The addition amount of the crystal seeds is 0.1%-1.5% of the mass of the methanol polyether.

3. The synthesis method according to claim 1, characterized in that, The alcohol salt 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 to 3, characterized in that The adsorbent includes at least one of aluminum silicate, magnesium silicate, and magnesium aluminum silicate.

5. The synthesis method according to claim 4, wherein The addition amount of the adsorbent is 0.5%-5% of the mass of the methanol polyether.

6. The synthesis method according to any one of claims 1-3, characterized in that The methyl chloride is added dropwise, and the dropping rate is 0.1-1.5 g / min; the dropping temperature is 50-70 °C.

7. The synthesis method according to any one of claims 1-3, characterized in that, The molar ratio of the methanol polyether to the alcohol salt reagent and the methyl chloride is 1.0:(1.1-1.8):(1.1-1.8).

8. The synthesis method according to claim 7, wherein The molar ratio of the methanol polyether to the alcohol salt reagent and the methyl chloride is 1.0:(1.1-1.5):(1.1-1.5).

9. The synthesis method according to any one of claims 1-3, characterized in that, The temperature of the aging reaction is 50-70 °C, and the time of the aging reaction is 0.5-5 h.

10. The synthesis method according to claim 9, characterized in that, The process of the secondary degassing is to degas for 0.5-2 h at 80-110 °C and a vacuum of -0.099 Mpa.

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