Methyl-terminated polyether refining treatment method

Abstract

The invention belongs to the technical field of polyether refining, and particularly relates to a methyl-terminated polyether refining treatment method. Comprising the following steps: adding water into a to-be-refined methyl-terminated polyether sample, stirring, dissolving salt in water, layering, adding water into a polyether layer again after separation, stirring, layering, and separating to obtain a primary sample; taking a methyl-terminated polyether sample to be refined again, heating, adding water, adjusting the pH with acid, and stirring to obtain a sample A; adding the preliminary sample into the sample A, and stirring to obtain a sample B; and adding acid into the sample B to adjust the pH value, continuously stirring, crystallizing the metal salt into large particles, settling, separating out solids, deacidifying and decolorizing, dehydrating in vacuum, and filtering to obtain qualified methyl-terminated polyether products, and intercepting part of qualified products as preliminary samples for continuous production. By adding the methyl-terminated polyether primary finished product, the crystallization process of the metal salt can be effectively improved, so that the metal salt tends to generate coarse particles easy to filter, the filtering resistance is reduced, and the filtering period is shortened.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyether refining, and particularly relates to a methyl-terminated polyether refining treatment method. BACKGROUND

[0002] Methyl-terminated polyether is widely used in many fields such as oil agent, lubricating oil, surfactant, etc. due to its unique performance in acid and alkali resistance, heat aging resistance, oil solubility, chemical stability, etc. Methyl-terminated polyether is currently mainly prepared by Williamson method. First, a strong alkaline reagent (sodium hydroxide, potassium hydroxide, sodium methoxide, potassium methoxide, sodium hydride, etc.) reacts with the terminal hydroxyl group of polyether to generate an alkoxide. Then, the alkoxide anion (RO - ) acts as a nucleophile to attack the carbon atom in halogenated hydrocarbon (methyl chloride, CH3-Cl), replace the halogen leaving group (Cl - ), and form an ether bond (R-O-CH3). For the end-capped product with high equivalent molecular weight, the final reaction product is a mixture of halide (sodium chloride or potassium chloride), end-capped polyether, unreacted strong base, and methyl chloride emulsion due to the long polyether chain and high viscosity, etc. Therefore, a complex post-treatment process is required to finally obtain a qualified product.

[0003] Currently, the post-treatment process of alkyl-terminated polyether mainly includes three methods: one method is to add a large amount of water to the reaction product to dissolve the salt, and then separate the alkyl-terminated polyether product by static layering. Patent CN102516524A introduces a post-treatment process of polypropylene oxide alkyl-terminated. After the end of polypropylene oxide termination, water is added and stirred; after stirring, it is left to separate layers; the terminated polypropylene oxide is separated from the salt water; water is added to the terminated polypropylene oxide for the second time, and stirred; the layers are separated again; the layers are separated again; the terminated polypropylene oxide is added with white clay to remove water; the terminated polypropylene oxide layer (ether layer) is dehydrated under vacuum; after dehydration of the ether layer, the white clay is removed by pressure filtration to obtain the terminated polypropylene oxide product, wherein the amount of water added each time is 25% to 30% of the weight of the terminated polyether. Patent CN101235144A adds about 50% by weight of water to the product, separates the layers by static layering, removes the water phase, dehydrates under vacuum, and filters to remove solid impurities to obtain the terminated polyether product. This method uses a large amount of water and generates a large amount of salt-containing wastewater, resulting in high production cost and long production cycle. Another method is to add acid and water to break the emulsion and allow the salt to crystallize and separate. This method does not require the use of a large amount of water, but the generated salt crystals are small, incomplete, difficult to filter, and the crystallized salt may adhere to the equipment, making it difficult to remove the salt completely at one time. In view of the above problems, patent CN110330640A solves the problem by adding 10-40wt.% of azeotrope (ethyl acetate, methyl tetrahydrofuran, etc.) to the system to increase the metastable zone width of the halide salt in the system and improve the salt crystallinity. The azeotrope introduced in this method may be slightly left in the final product, causing a certain degree of product contamination, which may limit downstream applications. The third method is to dissolve the terminated product by adding a solvent, allow the metal salt to precipitate, and separate it with saturated brine, and finally separate by static layering. Patent CN102276823A adds ethylene glycol ether solvent to the methyl-terminated polyoxyethylene ether, washes with a saturated solution of chloride salt, separates the upper layer, removes the solvent and water by vacuum distillation, and obtains the methyl-terminated polyoxyethylene ether. This method uses a large amount of solvent, which also has the risk of contaminating the product with residual solvent. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a methyl-terminated polyether refining method, which solves the problem of incomplete crystallization of metal salt in the existing methyl-terminated polyether refining process, resulting in slow filtration speed, adhesion of metal salt and adhesion to equipment, and no other components remaining in the product.

[0005] The methyl-terminated polyether refining method of the present application comprises the following steps: (1) First add water to the methyl-terminated polyether sample to be refined, stir, and separate after the salt dissolves in water; then add water to the polyether layer again, stir, and separate after layering to obtain a preliminary sample; (2) Take the methyl-terminated polyether sample to be refined again, heat, add water, adjust the pH with an acid, and continue to stir to obtain sample A; (3) Add the preliminary sample to sample A, continue to stir for 0.5-2 hours to obtain sample B; (4) Adjust the pH of sample B with an acid and continue to stir for 0.5-2 hours; at this time, the metal salt crystallizes into large particles and does not stick together; after the solid is separated, the liquid is the crude product; add an adsorbent to the crude product and stir to perform deacidification and decolorization treatment, then vacuum dehydrate, and filter again to obtain colorless and clear methyl-terminated polyether qualified products; the intercepted part of the qualified products is used as the preliminary sample for continuous production.

[0006] The technical solution process diagram of the present application is shown in Figure 1 .

[0007] In step (1), the first water stirring is adding 20-30% of the water to the methyl-terminated polyether sample to be refined and stirring for 0.5-2 hours; and in step (1), the second water stirring is adding 20-30% of the water to the methyl-terminated polyether sample to be refined and stirring for 0.5-2 hours.

[0008] In step (2), the heating is heating to 80-90°C, and the water adding is adding 3-5% of the water to the methyl-terminated polyether sample to be refined.

[0009] In step (2), the pH adjustment with an acid is adjusting the pH to 8.0-9.0.

[0010] In step (2), the acid is phosphoric acid, sulfuric acid, hydrochloric acid, acetic acid, oxalic acid, or citric acid, preferably phosphoric acid.

[0011] In step (3), the preliminary sample is added in an amount of 20-40% of the methyl-terminated polyether sample to be refined in step (2).

[0012] In step (4), the pH adjustment with an acid is adjusting the pH to 4.5-5.0.

[0013] In step (4), the adsorbent is one or two of magnesium silicate, aluminum silicate, magnesium aluminum silicate, or decolorizing clay, and the adsorbent is added in an amount of 1‰-2% of the sample B, preferably 5‰-1%.

[0014] In step (4), the temperature of adding the adsorbent and stirring is 60-90°C, and the stirring time is 0.5-3.0 hours.

[0015] The temperature of the vacuum dehydration in step (4) is 105-120 DEG C, and the pressure is less than or equal to -0.085 MPa.

[0016] The time of the vacuum dehydration in step (4) is 1-3 hours.

[0017] Compared with the prior art, the present application has the following advantages: 1) The present application can effectively improve the crystallization process of metal salt by adding the methyl-terminated polyether primary product, which lowers the metal salt concentration, widens the crystallization metastable zone width, and the methyl-terminated polyether itself is an excellent surfactant, which can lower the interfacial tension, adjust the crystal growth environment, and make the metal salt tend to generate coarse particles which are easy to filter, thereby reducing the filtration resistance and shortening the filtration period.

[0018] 2) The present application does not need to introduce additional substances such as azeotropes, and will not pollute the product.

[0019] 3) The present application can effectively inhibit the adhesion of metal salt and the adhesion to equipment, reduce the filtration times, improve the product first-pass yield, and reduce the polyether residue and improve the product yield.

[0020] 4) The present application traps part of the qualified products as additives for the next refining process, realizing continuous production.

[0021] 5) The refining process of the present application uses small amount of water, does not produce a large amount of salt-containing wastewater, has short refining period, and high production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The technical scheme flowchart of the present application. DETAILED DESCRIPTION

[0023] The present application is further described below in combination with examples.

[0024] All raw materials used in the examples are commercially available, except for special instructions.

[0025] The decoloring clay is purchased from Lüping City Clean Bleaching Clay Co., Ltd., and the brand is JJ-01.

[0026] Example 1 Synthesis of methyl-terminated polyether: A, synthesis of base polyether oligomer (LMP): in a dry and sealed 5L reactor, add 500g of n-butanol and 4.08g of potassium hydroxide catalyst, replace three times with nitrogen gas, heat to 102.5±2.5℃, add 2698.30g of propylene oxide and 674.57g of ethylene oxide mixture, reaction temperature 112.5±2.5℃, pressure 0.15±0.15MPa, after the end of the drop, keep the temperature for 2h, degas for 30min, and then cool to 65±5℃ before discharging.

[0027] B, synthesis of base polyether: add 670g of oligomer (LMP) and 5.00g of potassium hydroxide catalyst to the reactor, replace three times with nitrogen gas, heat to 107.5±2.5℃, dehydrate under negative pressure for 1h, then add 2358.40g of propylene oxide and 589.61g of ethylene oxide mixture, reaction temperature 112.5±2.5℃, pressure 0.15±0.15MPa, after the end of the drop, keep the temperature for 2h, degas for 30min, and then cool to 65±5℃ before discharging (hydroxyl value 26.6mg KOH / g), to obtain the base polyether.

[0028] C, take 2000g of the above base polyether in a 3L batch reactor, add 62.7g of sodium methoxide solid powder, stir and heat to 110℃, control the temperature, vacuum degree-0.09MPa~ -0.1MPa, react for 3h, then cool to 60℃ and pass in 52.7g of methyl chloride, constant temperature 60℃ for 3h, after removing the unreacted methyl chloride, the methyl-terminated polyether to be refined is obtained.

[0029] The methyl-terminated polyether refining method comprises the following steps: (1) add 100g of water to 500g of the methyl-terminated polyether sample to be refined and stir for 0.5h, so that the salt dissolves in water, then stand for two-phase separation, take the upper clear polyether layer and add 100g of water again, stir for 0.5h, stand for separation, and remove the water phase to obtain a preliminary sample; (2) take 1000g of the methyl-terminated polyether sample to be refined again, stir and heat to 80℃, add 30g of water, adjust the pH value of the system to 8.86 with phosphoric acid, continue to stir, and obtain sample A; (3) add 200g of the preliminary sample to sample A, continue to stir for 0.5h, and obtain sample B; (4) To sample B, add phosphoric acid to adjust the pH value to 4.63, and continue stirring for 0.5 h, at this time the metal salt crystallizes into large particles and settles, and no adhesion phenomenon occurs, after separating the solid, the remaining liquid is the crude product, add 1.2 g of magnesium aluminum silicate adsorbent to the crude product and stir at 60°C for 0.5 h, then perform deacidification and decolorization treatment, then open the vacuum dewatering, the temperature of vacuum dewatering is 105°C, the pressure is ≤-0.085 MPa, the dewatering time is 1 h, then filter and separate the adsorbent, to obtain colorless and clear methyl-terminated polyether qualified product (end-capping rate 98.7%, Na + content 2 ppm, acid value 0.023 mgKOH / g, moisture 0.016 wt.%); the cut part qualified product is used as a preliminary sample for continuous production.

[0030] Comparative Example 1 Take 1000 g of the methyl-terminated polyether sample to be refined in Example 1, stir and heat to 80°C, add 30 g of water, adjust the pH value of the system to 4.56 with phosphoric acid and stir for 0.5 h, at this time the metal salt crystallizes into fine particles that are sticky and adhere to the equipment, after filtration, add 5 g of magnesium aluminum silicate adsorbent to the liquid phase and stir at 80°C for 0.5 h, then perform deacidification and decolorization treatment, then open the vacuum dewatering, the temperature of vacuum dewatering is 105°C, the pressure is ≤-0.085 MPa, the dewatering time is 1 h. Then filter and separate the adsorbent, to obtain clear and transparent finished product (end-capping rate 98.7%, Na + content 6 ppm, acid value 0.039 mgKOH / g, moisture 0.022 wt.%).

[0031] Example 2 Synthesis of methyl-terminated polyether: A, synthesis of basic polyether oligomer (LMP): at room temperature, add 350 g of methanol and 6.0 g of potassium methoxide catalyst to a dry and well-sealed 5 L reaction kettle, replace with nitrogen three times, heat to 102.5±2.5°C, add 3478.13 g of propylene oxide dropwise, the reaction temperature is 112.5±2.5°C, the pressure is 0.15±0.15 MPa, after the dropwise addition is completed, keep the temperature for 2 h, degas for 30 min, and then discharge after cooling to 65±5°C.

[0032] B, synthesis of basic polyether: after the above polyether refining and desalting treatment, take 500 g and add to the reaction kettle, add 30 ppm of DMC bimetallic catalyst and 15 ppm of sulfuric acid, pre-drip propylene oxide until the system is initiated, then continuously introduce propylene oxide for a total of 2695.61 g, the reaction temperature is 127.5±2.5°C, the pressure is 0.05±0.05 MPa, after the dropwise addition is completed, keep the temperature for 2 h, degas for 30 min, and then discharge after cooling to 65±5°C, to obtain basic polyether (hydroxyl value 34.6 mg KOH / g).

[0033] C. Synthesis of methyl-terminated polyether: Take 2000 g of the above base polyether in a 3 L batch reactor, add 80.0 g of sodium methoxide solid powder, stir and heat, control the temperature at 120℃, vacuum degree -0.09MPa~ -0.1MPa, react for 3 h, then cool to 70℃, and then pass in 67.9 g of methyl chloride, keep the temperature at 70℃ for 5 h, after removing the unreacted methyl chloride, the methyl-terminated polyether crude product is obtained.

[0034] The methyl-terminated polyether refining treatment method comprises the following steps: (1) First add 130 g of water to 500 g of the methyl-terminated polyether sample to be refined, stir for 1.5 h, allow the salt to dissolve in water, and then separate the two phases after standing, take the upper clear polyether layer, add 130 g of water again, stir for 1.5 h, and then remove the water phase after standing and separating, to obtain a preliminary sample; (2) Take 1000 g of the methyl-terminated polyether sample to be refined again, stir and heat to 85℃, add 40 g of water, adjust the pH value of the system to 8.91 with phosphoric acid, and continue to stir to obtain sample A; (3) Add 330 g of the preliminary sample to sample A, continue to stir for 2 h to obtain sample B; (4) Add phosphoric acid to sample B to adjust the pH value to 4.59, and continue to stir for 2 h, at this time the metal salt crystallizes into large particles and does not stick together, after separating the solid, the liquid left is the crude product, add 6.5 g of magnesium silicate and 5 g of decolorizing clay adsorbent to the crude product, stir at 80℃ for 2 h for deacidification and decolorization treatment, then open the vacuum dehydration, the temperature for vacuum dehydration is 110℃, the pressure is ≤-0.085MPa, and the dehydration time is 2 h, then filter and separate the adsorbent, to obtain colorless and clear methyl-terminated polyether qualified product (end-capping rate 97.1%, Na + content 1 ppm, acid value 0.036 mgKOH / g, moisture 0.019 wt.%); the cut part of the qualified product is used as the preliminary sample for continuous production.

[0035] Example 3 Synthesis of methyl-terminated polyether: A. Synthesis of base polyether: at room temperature, add allyl alcohol 360 g and 5.3 g of sodium methoxide catalyst in a dry and well-sealed 5 L reactor, replace with nitrogen three times, heat to 102.5±2.5℃, add a mixture of 1530 g of propylene oxide and 1530 g of ethylene oxide, the reaction temperature is 120±2.5℃, the pressure is 0.15±0.15MPa, after the addition is completed, keep the temperature for 2 h, degas for 30 min, then cool to 65±5℃ and discharge, to obtain the base polyether (hydroxyl value 102.6 mgKOH / g).

[0036] B. Synthesis of methyl-terminated polyether: 2000 g of the above-mentioned basic polyether was placed in a 3 L batch reactor, 153.6 g of sodium hydroxide solid powder was added, and the mixture was stirred and heated. The temperature was controlled at 110℃, and the vacuum degree was -0.09 MPa to -0.1 MPa. The reaction was carried out for 3 h, and then cooled to 80℃. 203 g of chloromethane was introduced, and the reaction was carried out at a constant temperature of 80℃ for 5 h. After removing unreacted chloromethane, crude methyl-terminated polyether was obtained.

[0037] The method for refining methyl-terminated polyether includes the following steps: (1) Add 150g of water to 500g of methyl-terminated polyether sample to be refined and stir for 2h to dissolve the salt in the water. After standing, let the two phases separate. Take the upper clear liquid polyether layer, add 150g of water again and stir for 2h. After standing and separating, remove the aqueous phase to obtain the preliminary sample. (2) Take another 1000g of the methyl-terminated polyether sample to be refined, stir and heat to 90℃, add 50g of water, adjust the pH of the system to 8.33 with phosphoric acid, continue stirring, and obtain sample A; (3) Add 400g of preliminary sample to sample A and continue stirring for 2 hours to obtain sample B; (4) Add phosphoric acid to sample B to adjust the pH to 4.86 and stir continuously for 2 hours. At this time, the metal salt crystals settle as large particles without sticking. After separating the solid, the remaining liquid is the crude product. Add 12g of aluminum silicate and 16g of magnesium silicate adsorbent to the crude product and stir at 90℃ for 3 hours to perform deacidification and decolorization treatment. Then turn on vacuum dehydration. The vacuum dehydration temperature is 120℃, the pressure is ≤-0.085MPa, and the dehydration time is 3 hours. Then filter to separate the adsorbent to obtain a colorless and clear qualified methyl-terminated polyether (termination rate 99.1%, Na + The content was 2 ppm, the acid value was 0.029 mg KOH / g, and the moisture content was 0.013 wt.%. A portion of the qualified product was retained as a preliminary sample for continuous production.

Claims

1. A method for refining methyl-terminated polyethers, characterized in that, Includes the following steps: (1) Add water to the methyl-terminated polyether sample to be purified for the first time and stir to dissolve the salt in water and separate the layers. After separation, add water to the polyether layer again and stir. After separation, obtain the preliminary sample. (2) Take the methyl-terminated polyether sample to be refined again, heat it, add water, adjust the pH with acid, and continue stirring to obtain sample A; (3) Add the preliminary sample to sample A and continue stirring to obtain sample B; (4) Add acid to sample B to adjust pH and stir continuously. At this time, the metal salt crystals will settle into large particles. After separating the solid, the remaining liquid is the crude product. Add adsorbent to the crude product and stir to carry out deacidification and decolorization treatment. Then dehydrate under vacuum and filter again to obtain qualified methyl-terminated polyether. Retain a portion of the qualified product as a preliminary sample for continuous production.

2. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The first addition of water and stirring in step (1) is to add water equal to 20%~30% of the mass of the methyl-terminated polyether sample to be refined and stir for 0.5h~2h. The second addition of water and stirring in step (1) is to add water equal to 20%~30% of the mass of the methyl-terminated polyether sample to be refined and stir for 0.5h~2h.

3. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The heating in step (2) is to raise the temperature to 80℃~90℃, and the water added is 3%~5% of the mass of the methyl-terminated polyether sample to be purified.

4. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The step (2) of adjusting the pH with acid is to adjust the pH to 8.0~9.

0.

5. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The amount of preliminary sample added in step (3) is 20% to 40% of the mass of the methyl-terminated polyether sample to be refined in step (2).

6. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The step (4) of adding acid to adjust the pH is to adjust the pH to 4.5~5.

0.

7. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The adsorbent in step (4) is one or two of magnesium silicate, aluminum silicate, magnesium aluminum silicate, and decolorizing clay, and the amount of adsorbent added is 1‰~2% of the mass of sample B.

8. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The temperature for adding the adsorbent and stirring in step (4) is 60℃~90℃, and the stirring time is 0.5h~3.0h.

9. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The vacuum dehydration temperature in step (4) is 105℃~120℃, and the pressure is ≤-0.085MPa.

10. The method for refining methyl-terminated polyether according to claim 1, characterized in that, The vacuum dehydration time in step (4) is 1h to 3h.

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