A method for purifying a polymerization inhibitor 5575
By utilizing the solubility gradient difference between methanol and isopropanol mixed solvents, the problem of decreased purity of polymerization inhibitor 5575 was solved through a method of dissolving at high temperature and crystallizing at low temperature, thus achieving efficient purification and resource reuse.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YANTAI SYNTHOLUTION NEW MATERIAL TECH CO
- Filing Date
- 2025-12-03
- Publication Date
- 2026-06-26
AI Technical Summary
Polymerization inhibitor 5575 has a short shelf life. After being stored for more than one year, it decomposes and degrades, and the number of disubstituted and monosubstituted impurities increases, affecting the product's performance.
The defective finished product was completely dissolved at high temperature using a solvent, and then slowly crystallized out by cooling in a water bath. The solid-liquid separation was achieved by combining the solubility gradient difference of the mixed solvent of methanol and isopropanol at low temperature, and high-purity polymerization inhibitor 5575 was obtained after filtration.
It effectively improves the purity of substandard finished products, reduces waste, lowers purification costs, increases product yield, and ensures that products meet standards and can continue to be used.
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Figure CN121248672B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of polymerization inhibitors, and more specifically, it relates to a method for purifying polymerization inhibitor 5575. Background Technology
[0002] Polymerization inhibitors are industrial additives typically used to prevent polymerization. Adding a specific amount of inhibitor to the system containing the polymer to be inhibited will achieve the desired polymerization inhibition effect. Inhibitor molecules react with chain radicals to form non-radical substances or low-activity free radicals that cannot be initiated, thereby terminating the polymerization.
[0003] Polymer inhibitor 5575 is mainly used as a stabilizer and inhibitor in polymer materials. Its main function is to inhibit oxidation and decomposition reactions in polymers during processing, storage, and use, thereby extending the polymer's service life. It is widely used in the polymer industry, such as in plastics, rubber, and fibers, for example, in the production of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and photocurable reactive diluents such as multifunctional acrylates.
[0004] There are two main methods for synthesizing polymerization inhibitor 5575 in existing technologies. One common method involves reacting phosphorus trichloride with a nitroxide radical compound under the action of a catalyst, followed by a series of separation and purification steps to obtain the target product. The other method involves reacting triethyl phosphite with a nitroxide radical compound under the action of a catalyst, followed by specific separation and purification steps to obtain the target product. These methods meet the needs of industrial production to a certain extent, but certain technical problems still exist in practical applications.
[0005] The product shelf life of polymerization inhibitor 5575 is short. If it is stored for more than 1 year, the product will decompose and degrade, and the disubstituted and monosubstituted impurities will increase, affecting the performance of the product. Summary of the Invention
[0006] In order to purify and reuse products with reduced purity while ensuring product performance and reducing waste, this application provides a purification method for polymerization inhibitor 5575.
[0007] This application provides a purification method for polymerization inhibitor 5575, which adopts the following technical solution:
[0008] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0009] Dissolution: Weigh out the substandard product of polymerization inhibitor 5575, add solvent, heat in a water bath and stir to keep warm until the solid is completely dissolved. After dissolution, keep warm for 30 minutes to obtain a solution for later use.
[0010] Cooling crystallization: Cool the solution in a water bath to 20-30℃ and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5~5℃, keep warm for 1 hour, filter, and obtain mother liquor and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0011] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0012] By adopting the above technical solution, the unqualified finished product is completely dissolved in a solvent at a high temperature to form a solution. Water bath cooling causes the product in the solution to slowly crystallize and precipitate. Continued cooling and maintaining a low temperature allows a large amount of the dissolved product to precipitate out. The product has low solubility in the solvent, while impurities have high solubility. As a result, after filtration, the mother liquor contains more impurities, while a large amount of product precipitates out. After solid-liquid separation, the solid is the purified polymerization inhibitor 5575, whose purity is greatly improved. This effectively purifies the unqualified finished product, reduces waste, and makes it meet the standards so that it can continue to be used as a qualified finished product.
[0013] Preferably, the purity of the unqualified product containing the polymerization inhibitor 5575 is 70-90%.
[0014] By adopting the above technical solution, the purity of unqualified finished products can be controlled, enabling unqualified finished products to be purified through this method to achieve the purity of qualified finished products, reducing product waste caused by impurities, and ensuring the yield and purity of qualified finished products of the method of this application.
[0015] Preferably, in the dissolution step, the solvent is a mixed solvent, and in the cooling crystallization step, the mother liquor is a primary filtrate.
[0016] Preferably, in the dissolution step, the solvent is a mixture of primary filtrate and mixed solvent, and in the cooling crystallization step, the mother liquor is secondary filtrate.
[0017] By adopting the above technical solution, adding a mixed solvent to the primary filtrate dilutes the primary filtrate, resulting in a decrease in the mass fraction of both product and impurities. The diluted primary filtrate can then be used to purify new substandard products, reducing the amount of mixed solvent used and lowering purification costs. Simultaneously, it allows some of the product from the primary filtrate to precipitate out during the next purification process, thereby improving the yield.
[0018] Preferably, the mixed solvent is one or more of methanol and isopropanol.
[0019] By adopting the above technical solution, methanol and isopropanol are selected. Both can dissolve the product and impurities at higher temperatures. As the temperature decreases, the solubility of the product and impurities decreases, and the solubility of impurities is higher than that of the product. As a result, more impurities remain in the mother liquor, and fewer impurities are precipitated.
[0020] Preferably, the mixed solvent comprises methanol and isopropanol in a mass ratio of (1-2):(1-2).
[0021] By adopting the above technical solution and controlling the mass ratio of methanol and isopropanol, the resulting mixed solvent has high solubility for impurities and low solubility for products at low temperatures, with a large solubility gradient between the two, thus enabling better separation of products and impurities.
[0022] Preferably, when the purity of the substandard product of polymerization inhibitor 5575 is 70-75%, the mass ratio of the substandard product of polymerization inhibitor 5575 to the mixed solvent is 1:4.3; when the purity of the substandard product of polymerization inhibitor 5575 is 75-80%, the mass ratio of the substandard product of polymerization inhibitor 5575 to the mixed solvent is 1:3.6; when the purity of the substandard product of polymerization inhibitor 5575 is 80-85%, the mass ratio of the substandard product of polymerization inhibitor 5575 to the mixed solvent is 1:2.9; and when the purity of the substandard product of polymerization inhibitor 5575 is 85-90%, the mass ratio of the substandard product of polymerization inhibitor 5575 to the mixed solvent is 1:2.2.
[0023] By adopting the above technical solution, the purity of the unqualified finished product of polymerization inhibitor 5575 varies. By adding mixed solvents of different masses, it is ensured that the solvent can fully dissolve the product and impurities in the unqualified finished product, and at low temperature, the impurities in the solvent will not precipitate due to excessive concentration.
[0024] Preferably, the amount of mixed solvent added in the mixture is 10-20 wt% of the mass of the primary filtrate.
[0025] By adopting the above technical solution, the amount of mixed solvent added can be controlled, thereby diluting the primary filtrate without consuming too much mixed solvent. This keeps the impurity concentration in the diluted primary filtrate within a certain range, allowing it to be used in the next purification process.
[0026] Preferably, the secondary filtrate is purified by distillation to obtain a reusable mixed solvent.
[0027] By adopting the above technical solution, the impurity concentration in the secondary filtrate is high. After purification by distillation, the impurities can be separated from the liquid, thereby realizing the regeneration of the mixed solvent and further reducing the cost of the purification method.
[0028] In summary, this application has the following beneficial effects:
[0029] 1. In this application, the unqualified finished product is completely dissolved in a solvent at a high temperature to form a solution. Water bath cooling causes the product in the solution to slowly crystallize and precipitate. Continued cooling and maintaining a low temperature allows a large amount of the dissolved product to precipitate out. The product has low solubility in the solvent, while impurities have high solubility. As a result, after filtration, the mother liquor contains a lot of impurities, while a large amount of product precipitates out. After solid-liquid separation, the solid is the purified polymerization inhibitor 5575, whose purity is greatly improved. This effectively purifies the unqualified finished product, reduces waste, and makes it meet the standards so that it can continue to be used as a qualified finished product.
[0030] 2. In this application, a mixed solvent is added to the primary filtrate, which dilutes the primary filtrate and reduces the mass fraction of both product and impurities in the primary filtrate. The diluted primary filtrate can be used to purify new substandard products, reducing the amount of mixed solvent used and lowering purification costs. At the same time, a portion of the product in the primary filtrate can be precipitated in the next purification process, thereby improving the yield.
[0031] 3. In this application, by controlling the mass ratio of methanol and isopropanol, the resulting mixed solvent has a high solubility for impurities and a low solubility for the product at low temperatures, resulting in a large solubility gradient between the two, thereby enabling better separation of the product from the impurities. Attached Figure Description
[0032] Figure 1 This is the detection spectrum of polymerization inhibitor 5575 after purification in Example 2;
[0033] Figure 2 This is the detection spectrum of polymerization inhibitor 5575 after purification in Example 10. Detailed Implementation
[0034] The present application will be further described in detail below with reference to the embodiments. Example
[0035] Example 1
[0036] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0037] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 72%, add 430g of mixed solvent, the mixed solvent is methanol and isopropanol with a mass ratio of 1:1, heat in a water bath and stir to keep warm until the solid is completely dissolved, keep warm for 30 minutes after dissolution, and obtain a solution for later use.
[0038] Cooling crystallization: Cool the solution in a water bath to 20°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5°C, keep warm for 1 hour, filter, and obtain the first filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0039] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0040] Example 2
[0041] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0042] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 90%, add 220g of mixed solvent, the mixed solvent is methanol and isopropanol with a mass ratio of 1:1, heat in a water bath and stir to keep warm until the solid is completely dissolved, keep warm for 30 minutes after dissolution, and obtain a solution for later use.
[0043] Cooling crystallization: Cool the solution in a water bath to 25°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to 0°C, keep it at that temperature for 1 hour, filter, and obtain the first filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0044] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0045] Example 3
[0046] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0047] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 86%, add 220g of mixed solvent, the mixed solvent is methanol and isopropanol with a mass ratio of 1:1, heat in a water bath and stir to keep warm until the solid is completely dissolved, keep warm for 30 minutes after dissolution, and obtain a solution for later use.
[0048] Cooling crystallization: Cool the solution in a water bath to 20°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5°C, keep warm for 1 hour, filter, and obtain the first filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0049] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0050] Example 4
[0051] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0052] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 77%, add 360g of mixed solvent, the mixed solvent is methanol and isopropanol with a mass ratio of 1:1, heat in a water bath and stir to keep warm until the solid is completely dissolved, keep warm for 30 minutes after dissolution, and obtain a solution for later use.
[0053] Cooling crystallization: Cool the solution in a water bath to 30°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to 5°C, keep it at that temperature for 1 hour, filter, and obtain the first filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0054] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0055] Example 5
[0056] The difference between Example 5 and Example 3 is that in Example 5, the mixed solvent is methanol of equal mass.
[0057] Example 6
[0058] The difference between Example 6 and Example 3 is that in Example 6, the mixed solvent is an equal mass of isopropanol.
[0059] Example 7
[0060] The difference between Example 7 and Example 3 is that in Example 7, the mixed solvent includes methanol and isopropanol in a 1:2 ratio.
[0061] Example 8
[0062] The difference between Example 8 and Example 3 is that in Example 8, the mixed solvent includes methanol and isopropanol in a 2:1 ratio.
[0063] Example 9
[0064] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0065] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 86%, add 220g of solvent, which is a mixture of primary filtrate and mixed solvent. The mixed solvent is methanol and isopropanol with a mass ratio of 1:1. The primary filtrate is the primary filtrate obtained in Example 3. The amount of mixed solvent added is 10wt% of the mass of the primary filtrate. Heat in a water bath and stir to keep warm until the solid is completely dissolved. After dissolution, keep warm for 30 minutes to obtain a solution for later use.
[0066] Cooling crystallization: Cool the solution in a water bath to 20°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5°C, keep it at that temperature for 1 hour, filter, and obtain a secondary filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0067] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0068] Example 10
[0069] A method for purifying polymerization inhibitor 5575 includes the following steps:
[0070] Dissolution: Weigh 100g of the unqualified product of polymerization inhibitor 5575 with a purity of 86%, add 220g of solvent, which is a mixture of primary filtrate and mixed solvent. The mixed solvent is methanol and isopropanol with a mass ratio of 1:1. The primary filtrate is the primary filtrate obtained in Example 3. The amount of mixed solvent added is 20wt% of the mass of the primary filtrate. Heat in a water bath and stir to keep warm until the solid is completely dissolved. After dissolution, keep warm for 30 minutes to obtain a solution for later use.
[0071] Cooling crystallization: Cool the solution in a water bath to 20°C and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5°C, keep it at that temperature for 1 hour, filter, and obtain a secondary filtrate and solid. Dry the solid to obtain the purified polymerization inhibitor 5575.
[0072] Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product.
[0073] Example 11
[0074] The difference between Example 11 and Example 9 is that in Example 11, the solvent is a primary filtrate.
[0075] Detection methods
[0076] According to Examples 1-11, purified products were prepared. Following standard Q / 370600 XTL 005-2021 "Yantai Xintelu New Material Technology Co., Ltd. Product Enterprise Standard for Polymer Inhibitor ZJ5755", the purity X0 of the unqualified finished product, the purity X1 of the product after one purification, and the purity X2 of the product after two purifications were tested, and the results are recorded in Table 1. The first and second yields of the qualified polymer inhibitor 5575 are also recorded in Table 1. Yield = (mass of purified polymer inhibitor 5575 obtained this time / mass of unqualified polymer inhibitor 5575 added this time) × 100%. The detection spectra of the polymer inhibitor 5575 purified in Examples 2 and 10 are shown below. Figure 1 and Figure 2 As shown.
[0077] Table 1. Detection of the Purification Method's Effectiveness
[0078] project <![CDATA[X0 / %]]> <![CDATA[X1 / %]]> First-time yield / % <![CDATA[X2 / %]]> Secondary yield / % Example 1 72 97.2 73 —— —— Example 2 90 98.6 84 —— —— Example 3 86 97.5 86 —— —— Example 4 77 99.2 68 —— —— Example 5 86 96.1 70 —— —— Example 6 86 98.0 50 —— —— Example 7 86 95.9 60 —— —— Example 8 86 96.0 82 —— —— Example 9 86 98.1 90 —— —— Example 10 86 99.1 88 —— —— Example 11 86 92.6 90 96.2 94.74
[0079] According to Table 1, Figure 1 As can be seen from Examples 1-4, the unqualified products of polymerization inhibitor 5575 with different purities in Examples 1-4 can achieve a purity of 96% or higher after one purification, which meets the purity standard of qualified products. Moreover, the product yield of the unqualified products is high and the loss is low. It can effectively separate the product from the impurities in the unqualified products, realize the recycling and purification of unqualified products, and ensure its use effect. Furthermore, the unqualified products of polymerization inhibitor 5575 with different purities only need to be purified once to meet the standard. The purification method is relatively simple and the purification effect is good. The unqualified products that should have been discarded are reused, reducing waste.
[0080] Compared with Example 3, the yield of Examples 5-8 decreased. In Examples 5-8, methanol, isopropanol, methanol and isopropanol in a mass ratio of 1:2 and methanol and isopropanol in a mass ratio of 2:1 were selected as mixed solvents, respectively. Although the purity still met the standard and could be used as a qualified finished product, the yield was low and there was a large loss of product during the purification process. It is speculated that the difference between the solubility of the product and the solubility of the impurities in the solvents used in Examples 5-8 was small at low temperatures, which could not meet the separation condition that "at low temperatures, the solubility of the product is much lower than the solubility of the impurities". Therefore, in Example 8, purity and yield could not be obtained at the same time.
[0081] Compared to Example 3, Examples 9-10 used a mixture of primary filtrate and mixed solvent as the solvent. Figure 2The results show that the product obtained in Example 10 has a purity of 99.1% and a high yield. Since there are residual products in the previous purification process in the first filtrate, they precipitate out along with the cooling crystallization during this purification process, reducing the total product loss. Furthermore, the recycling of the first filtrate can reduce the application and consumption of methanol and isopropanol, thereby effectively reducing the cost of purification operations.
[0082] Compared to Example 9, Example 11 showed a decrease in the initial purification effect, requiring two purification steps to obtain a qualified finished product. In Example 11, the initial filtrate was not diluted, resulting in a decrease in the initial purification effect. This is presumably because the initial filtrate contained some product and impurities, leading to an excessively high impurity content in the solution when used as a solvent. At low temperatures, a large amount of impurities precipitated, resulting in a higher impurity content in the precipitated solid and affecting the purity of the purified product. Since the initial filtrate contained both impurities and product, its initial purification yield was relatively high. After using a pure mixed solvent in the second purification, both the yield and purity improved compared to the first purification.
[0083] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A method for purifying polymerization inhibitor 5575, characterized in that: Includes the following steps: Dissolution: Weigh out the substandard product of polymerization inhibitor 5575, add solvent, heat in a water bath while stirring and keeping warm until all the solid is dissolved. After dissolution, keep warm for 30 minutes to obtain a solution for later use. The purity of the substandard product of polymerization inhibitor 5575 is 70-90%. When the solvent is a mixed solvent, the mass ratio of the unqualified polymer inhibitor 5575 to the mixed solvent is 1:4.3 when the purity of the unqualified polymer inhibitor 5575 is 70-75%; 1:3.6 when the purity of the unqualified polymer inhibitor 5575 is 75-80%; 1:2.9 when the purity of the unqualified polymer inhibitor 5575 is 80-85%; and 1:2.2 when the purity of the unqualified polymer inhibitor 5575 is 85-90%. Cooling crystallization: Cool the solution in a water bath to 20-30℃ and reduce the stirring rate until solid precipitates. Use a cooling liquid to circulate and cool to -5~5℃, keep warm for 1 hour, filter, and obtain mother liquor and solid. Dry the solid to obtain the purified polymerization inhibitor 5575. In the cooling crystallization step, the mother liquor is the primary filtrate. Testing: Test the purity of the purified polymerization inhibitor 5575. If the purity is <96%, repeat the above steps. If the purity is ≥96%, then the polymerization inhibitor 5575 is a qualified finished product. The mixed solvent is selected from one or more of methanol and isopropanol. When the mixed solvent is selected from methanol and isopropanol, the mass ratio of methanol to isopropanol is (1-2):(1-2).
2. The purification method for polymerization inhibitor 5575 according to claim 1, characterized in that: In the dissolution step, the solvent is a mixture of primary filtrate and mixed solvent; therefore, in the cooling crystallization step, the mother liquor is secondary filtrate.
3. The purification method for polymerization inhibitor 5575 according to claim 2, characterized in that: In the mixture, the amount of mixed solvent added is 10-20 wt% of the mass of the primary filtrate.
4. The purification method for polymerization inhibitor 5575 according to claim 3, characterized in that: The secondary filtrate is purified by distillation to obtain a reusable mixed solvent.