Instant polyacrylamide and preparation method thereof

Abstract

The invention relates to instant polyacrylamide and a preparation method thereof, and relates to the technical field of polyacrylamide preparation. The instant polyacrylamide is prepared from the following raw materials in parts by mass: 10 to 20 parts of acrylic acid, 60 to 70 parts of acrylamide, 50 to 60 parts of dimethyl diallyl ammonium chloride, 40 to 46 parts of a temperature-resistant and salt-resistant agent, 0.05 to 0.15 part of an initiator and 220 to 240 parts of deionized water, wherein the temperature-resistant and salt-resistant agent comprises 2-acrylamido octyl sulfonic acid; the method has the effect of improving the temperature resistance and salt resistance of polyacrylamide.

Description

Technical Field

[0001] The present application relates to the technical field of polyacrylamide preparation, and in particular to a fast-dissolving polyacrylamide and a preparation method thereof. Background Art

[0002] Polyacrylamide is one of the common water-soluble polymers. It has excellent hydrophilicity and high viscosity-increasing ability in aqueous solutions, so it is widely used in industries such as water treatment, mineral processing, papermaking, oil displacement, and fracturing.

[0003] Since polyacrylamide is prone to hydrolysis at high temperatures, and the carboxyl groups generated after hydrolysis are extremely sensitive to salts, resulting in a significant reduction in the viscosity of the aqueous solution, the temperature and salt resistance of polyacrylamide are poor. Summary of the Invention

[0004] In order to improve the temperature and salt resistance of polyacrylamide, the present application provides a fast-dissolving polyacrylamide and a preparation method thereof.

[0005] In a first aspect, a fast-dissolving polyacrylamide provided by the present application adopts the following technical solution: A fast-dissolving polyacrylamide includes the following raw materials in parts by mass: 10-20 parts of acrylic acid, 60-70 parts of acrylamide, 50-60 parts of dimethyldiallylammonium chloride, 40-46 parts of a temperature and salt resistant agent, 0.05-0.15 parts of an initiator, and 220-240 parts of deionized water. The temperature and salt resistant agent includes 2-acrylamidooctanesulfonic acid.

[0006] By adopting the above technical solution, 2-acrylamidooctanesulfonic acid containing a sulfonic group is introduced during the preparation of polyacrylamide to participate in the polymerization reaction, and a copolymer with an ionic surfactant side chain can be obtained. Under the action of the sulfonic group, such polymers can not only promote the dissolution and dispersion of monomers in the aqueous system, enabling the reaction to proceed uniformly, effectively improving the fast solubility of polyacrylamide. Moreover, the temperature and salt resistance of polyacrylamide are improved due to the insensitivity of the sulfonic group to salts.

[0007] Preferably, the preparation method of the 2-acrylamidooctanesulfonic acid includes the following steps: Mix 1-octene, acrylonitrile and an inhibitor, stir continuously, then add fuming sulfuric acid. After the reaction is completed, wash and dry in sequence to obtain 2-acrylamidooctanesulfonic acid.

[0008] By adopting the above technical solution, after mixing 1-octene, acrylonitrile and fuming sulfuric acid, a surfactant containing a sulfonic group is prepared and made to participate in the copolymerization reaction of polyacrylamide preparation, which thus has a positive effect on the temperature and salt resistance of polyacrylamide.

[0009] Preferably, the mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid is 1:6:(0.9-1.1).

[0010] By adopting the above technical solution, controlling the mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid within the above range effectively improves the yield of 2-acrylamidooctanesulfonic acid.

[0011] Preferably, the polymerization inhibitor includes p-methoxyphenol and 2,6-di-tert-butyl-p-cresol.

[0012] By adopting the above technical solution, during the preparation of 2-acrylamidooctanesulfonic acid, adding a polymerization inhibitor reduces the possibility of no product formation when the acrylonitrile proportion is low and the low product yield when the acrylonitrile proportion is high.

[0013] Preferably, the temperature and salt tolerance agent further includes N-vinylpyrrolidone.

[0014] By adopting the above technical solution, the cyclic structure in the N-vinylpyrrolidone molecule can increase the viscoelasticity of the polymer molecular chain containing sulfonic acid groups, so as to improve the stability of polyacrylamide, thereby improving the temperature and salt tolerance of polyacrylamide, and can also inhibit the hydrolysis of amide groups in the polymer and improve the hydrolysis resistance of polyacrylamide.

[0015] Preferably, the mass ratio of 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone is 1:(0.82-0.88).

[0016] By adopting the above technical solution, controlling the mass ratio of 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone within the above range can effectively improve the temperature and salt tolerance of polyacrylamide.

[0017] Preferably, the N-vinylpyrrolidone is prepared by modification. The modification preparation of N-vinylpyrrolidone includes the following steps: Dissolve N-vinylpyrrolidone in an aqueous solution of N-vinylpyrrolidone, add hydrochloric acid, stir evenly, then add betaine, fully stir and then perform drying and dehydration, then add absolute ethanol, fully stir, and then add acetone, fully stir and then filter and evaporate to obtain modified N-vinylpyrrolidone.

[0018] By adopting the above technical solution, betaine modifies N-vinylpyrrolidone, introducing carboxylic acid organic salts on N-vinylpyrrolidone, thereby improving the stability of N-vinylpyrrolidone in the polymer.

[0019] Preferably, the mass ratio of N-vinylpyrrolidone and betaine is 1:(0.23-0.33).

[0020] By adopting the above technical solution, controlling the mass ratio of N-vinylpyrrolidone to betaine within the above range has a positive effect on improving the stability of N-vinylpyrrolidone in the polymer.

[0021] Preferably, the initiator includes potassium persulfate and sodium bisulfite.

[0022] In a second aspect, a preparation method of a fast-dissolving polyacrylamide provided by the present application adopts the following technical solution: Preferably, after mixing acrylic acid, 2-acrylamidooctanesulfonic acid and deionized water, nitrogen is introduced for protection and fully stirred, then sodium hydroxide is added to adjust the pH value, and then an aqueous solution of acrylamide and dimethyldiallylammonium chloride in deionized water is added, and then the temperature is raised. Finally, an initiator is added, and after stirring evenly, the temperature is raised for reaction. After the reaction is completed, the product is sheared and dried to obtain polyacrylamide.

[0023] In summary, the present application includes at least one of the following beneficial technical effects: 1. Introducing 2-acrylamidooctanesulfonic acid containing a sulfonic acid group into the polyacrylamide preparation process to participate in the polymerization reaction can obtain a copolymer with an ionic surfactant side chain. Under the action of the sulfonic acid group, such polymers can not only promote the dissolution and dispersion of monomers in the aqueous system, enabling the reaction to proceed uniformly, effectively improving the fast solubility of polyacrylamide. Moreover, the temperature and salt resistance of polyacrylamide are improved by the insensitivity of the sulfonic acid group to salts.

[0024] 2. The cyclic structure in the N-vinylpyrrolidone molecule can increase the viscoelasticity of the polymer molecular chain containing a sulfonic acid group, so as to improve the stability of polyacrylamide, thereby improving the temperature and salt resistance of polyacrylamide, and can also inhibit the hydrolysis of the amide group in the polymer, improving the hydrolysis resistance of polyacrylamide. Specific embodiments

[0025] The raw materials involved in the present application can all be obtained commercially. Among them, acrylic acid (CAS number: 79-10-7) is provided by Jiangsu Yulong Chemical Co., Ltd., acrylamide (CAS number: 79-06-1) is provided by Shandong Yukang Chemical Co., Ltd., dimethyldiallylammonium chloride (CAS number: 7398-69-8) is provided by Zouping Mingxing Chemical Co., Ltd., 1-octene (CAS number: 111-66-0) is provided by Shanghai Biyang Industrial Co., Ltd., acrylonitrile (CAS number: 107-13-1) is provided by Jinan Chuangshi Chemical Co., Ltd., N-vinylpyrrolidone (CAS number: 88-12-0) is provided by Hubei Nuodina Biotechnology Co., Ltd., and betaine (CAS number: 107-43-7) is provided by Hebei Zhentian Food Additive Co., Ltd.

[0026] Example 1 The polyacrylamide comprises the following raw materials by weight: 10 g of acrylic acid, 60 g of acrylamide, 50 g of dimethyldiallylammonium chloride, 40 g of a heat and salt resistant agent, 0.05 g of an initiator, and 220 g of deionized water.

[0027] The temperature-resistant and salt-resistant agent includes 2-acrylamido octane sulfonic acid, and the initiator includes potassium persulfate and sodium bisulfite, and the mass ratio of potassium persulfate to sodium bisulfite is 2:1.

[0028] The preparation method of 2-acrylamido octane sulfonic acid comprises the following steps: 1-octene, acrylonitrile and polymerization inhibitor were mixed and stirred continuously, and fuming sulfuric acid (mass concentration of fuming sulfuric acid was 50%) was slowly added dropwise using a dropping funnel, the temperature during the addition was 2°C, and the addition time was 2h. After the addition was completed, the mixture was stirred for 30min, and then the temperature was raised to 25°C and the reaction was carried out for 24h. The product was then washed with acetone and dried in vacuo to obtain 2-acrylamidooctane sulfonic acid.

[0029] The mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid is 1:6:0.9, the inhibitor includes p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol, the mass ratio of p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol is 1:1, and the inhibitor accounts for 0.006% of the total amount of 1-octene, acrylonitrile and fuming sulfuric acid.

[0030] The preparation method of polyacrylamide comprises the following steps: After acrylic acid, heat-resistant and salt-resistant agent and deionized water are mixed, nitrogen is introduced for protection and the mixture is fully stirred. Then sodium hydroxide is added to adjust the pH value to 8, and then acrylamide and dimethyldiallyl ammonium chloride are added. After deoxygenation for 40 minutes, an initiator is added. After reacting for 6 hours under stirring, the temperature is raised to 20°C and the reaction is carried out for 6 hours. After the reaction is completed, the product is taken out, sheared, and dried at 75°C for 2 hours to obtain polyacrylamide.

[0031] Example 2 The polyacrylamide comprises the following raw materials by weight: 20 g of acrylic acid, 70 g of acrylamide, 60 g of dimethyldiallylammonium chloride, 46 g of a heat and salt resistant agent, 0.15 g of an initiator, and 240 g of deionized water.

[0032] The temperature-resistant and salt-resistant agent includes 2-acrylamido octane sulfonic acid, and the initiator includes potassium persulfate and sodium bisulfite, and the mass ratio of potassium persulfate to sodium bisulfite is 2:1.

[0033] The preparation method of acrylamido octane sulfonic acid comprises the following steps: 1-octene, acrylonitrile and polymerization inhibitor were mixed and stirred continuously, and fuming sulfuric acid (mass concentration of fuming sulfuric acid was 50%) was slowly added dropwise using a dropping funnel, the temperature during the addition was 2°C, and the addition time was 2h. After the addition was completed, the mixture was stirred for 30min, and then the temperature was raised to 25°C and the reaction was carried out for 24h. The product was then washed with acetone and dried in vacuo to obtain 2-acrylamidooctane sulfonic acid.

[0034] The mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid is 1:6:1.1, the inhibitor includes p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol, the mass ratio of p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol is 1:1, and the inhibitor accounts for 0.006% of the total amount of 1-octene, acrylonitrile and fuming sulfuric acid.

[0035] After acrylic acid, heat-resistant and salt-resistant agent and deionized water are mixed, nitrogen is introduced for protection and the mixture is fully stirred. Then sodium hydroxide is added to adjust the pH value to 8, and then acrylamide and dimethyldiallyl ammonium chloride are added. After deoxygenation for 40 minutes, an initiator is added. After reacting for 6 hours under stirring, the temperature is raised to 20°C and the reaction is carried out for 6 hours. After the reaction is completed, the product is taken out, sheared, and dried at 75°C for 2 hours to obtain polyacrylamide.

[0036] Example 3 The polyacrylamide comprises the following raw materials by weight: 15 g of acrylic acid, 65 g of acrylamide, 55 g of dimethyldiallylammonium chloride, 43 g of a heat and salt resistant agent, 0.1 g of an initiator, and 230 g of deionized water.

[0037] The temperature-resistant and salt-resistant agent includes 2-acrylamido octane sulfonic acid, and the initiator includes potassium persulfate and sodium bisulfite, and the mass ratio of potassium persulfate to sodium bisulfite is 2:1.

[0038] The preparation method of acrylamido octane sulfonic acid comprises the following steps: 1-octene, acrylonitrile and polymerization inhibitor were mixed and stirred continuously, and fuming sulfuric acid (mass concentration of fuming sulfuric acid was 50%) was slowly added dropwise using a dropping funnel, the temperature during the addition was 2°C, and the addition time was 2h. After the addition was completed, the mixture was stirred for 30min, and then the temperature was raised to 25°C and the reaction was carried out for 24h. The product was then washed with acetone and dried in vacuo to obtain 2-acrylamidooctane sulfonic acid.

[0039] The mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid is 1:6:1, the inhibitor includes p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol, the mass ratio of p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol is 1:1, and the inhibitor accounts for 0.006% of the total amount of 1-octene, acrylonitrile and fuming sulfuric acid.

[0040] The preparation method of polyacrylamide comprises the following steps: After mixing acrylic acid, a temperature- and salt-resistant agent, and deionized water, nitrogen was introduced for protection and thorough stirring was carried out. Then, sodium hydroxide was added to adjust the pH value to 8. Subsequently, acrylamide and dimethyldiallylammonium chloride were added. After deoxygenation for 40 minutes, an initiator was added, and the reaction was carried out under stirring for 6 hours. Then, the temperature was raised to 20 °C and the reaction was continued for 6 hours. After the reaction ended, the product was taken out, sheared, and dried at 75 °C for 2 hours to obtain polyacrylamide.

[0041] Example 4 The difference between Example 4 and Example 3 lies in that: the temperature- and salt-resistant agent includes 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, and the mass ratio of 2-acrylamidooctanesulfonic acid to N-vinylpyrrolidone is 1:0.82.

[0042] The preparation method of the temperature- and salt-resistant agent includes the following steps: After mixing 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, stir evenly to obtain the temperature- and salt-resistant agent.

[0043] Example 5 The difference between Example 5 and Example 3 lies in that: the temperature- and salt-resistant agent includes 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, and the mass ratio of 2-acrylamidooctanesulfonic acid to N-vinylpyrrolidone is 1:0.88.

[0044] The preparation method of the temperature- and salt-resistant agent includes the following steps: After mixing 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, stir evenly to obtain the temperature- and salt-resistant agent.

[0045] Example 6 The difference between Example 6 and Example 3 lies in that: the temperature- and salt-resistant agent includes 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, and the mass ratio of 2-acrylamidooctanesulfonic acid to N-vinylpyrrolidone is 1:0.85.

[0046] The preparation method of the temperature- and salt-resistant agent includes the following steps: After mixing 2-acrylamidooctanesulfonic acid and N-vinylpyrrolidone, stir evenly to obtain the temperature- and salt-resistant agent.

[0047] Example 7 The difference between Example 7 and Example 6 lies in that: the mass ratio of 2-acrylamidooctanesulfonic acid to N-vinylpyrrolidone is 1:0.72.

[0048] Example 8 The difference between Example 8 and Example 6 lies in that: the mass ratio of 2-acrylamidooctanesulfonic acid to N-vinylpyrrolidone is 1:0.98.

[0049] Example 9 Example 9 is different from Example 6 in that N-vinylpyrrolidone is prepared by modification. The preparation of the modified N-vinylpyrrolidone includes the following steps: After preparing 10 g of N-vinylpyrrolidone into an aqueous solution of N-vinylpyrrolidone with a mass concentration of 60%, 2 g of hydrochloric acid is added. After stirring and mixing thoroughly for 18 h, 2.3 g of betaine is added. After stirring and mixing thoroughly for 3 h, drying and dehydration are carried out, and then it is added to 20 g of absolute ethanol. After stirring thoroughly for 3 h, finally 40 g of acetone is added. After stirring thoroughly, filtration and evaporation are carried out to obtain modified N-vinylpyrrolidone.

[0050] Example 10 Example 10 is different from Example 6 in that N-vinylpyrrolidone is prepared by modification. The preparation of the modified N-vinylpyrrolidone includes the following steps: After preparing 10 g of N-vinylpyrrolidone into an aqueous solution of N-vinylpyrrolidone with a mass concentration of 60%, 2 g of hydrochloric acid is added. After stirring and mixing thoroughly for 18 h, 3.3 g of betaine is added. After stirring and mixing thoroughly for 3 h, drying and dehydration are carried out, and then it is added to 20 g of absolute ethanol. After stirring thoroughly for 3 h, finally 40 g of acetone is added. After stirring thoroughly, filtration and evaporation are carried out to obtain modified N-vinylpyrrolidone.

[0051] Example 11 Example 11 is different from Example 6 in that N-vinylpyrrolidone is prepared by modification. The preparation of the modified N-vinylpyrrolidone includes the following steps: After preparing 10 g of N-vinylpyrrolidone into an aqueous solution of N-vinylpyrrolidone with a mass concentration of 60%, 2 g of hydrochloric acid is added. After stirring and mixing thoroughly for 18 h, 2.8 g of betaine is added. After stirring and mixing thoroughly for 3 h, drying and dehydration are carried out, and then it is added to 20 g of absolute ethanol. After stirring thoroughly for 3 h, finally 40 g of acetone is added. After stirring thoroughly, filtration and evaporation are carried out to obtain modified N-vinylpyrrolidone.

[0052] Example 12 Example 12 is different from Example 11 in that the mass ratio of N-vinylpyrrolidone to betaine is 1:0.13.

[0053] Example 13 Example 13 is different from Example 11 in that the mass ratio of N-vinylpyrrolidone to betaine is 1:0.43.

[0054] Comparative Example 1 Comparative Example 1 is different from Example 3 in that it does not contain a temperature and salt tolerance agent.

[0055] Performance test: The high-temperature and salt-resistant polyacrylamide obtained in the examples and comparative examples was respectively formulated into an aqueous solution with a weight of 0.15%, and the apparent viscosity of each aqueous solution was measured, and the test results were recorded in Table 1.

[0056] Among them, the apparent viscosity of the high-temperature and salt-resistant polyacrylamide aqueous solution was measured by a Brookfield viscometer, the test temperature was 100 °C, and the salinity was 48000 mg / L.

[0057] Table 1 Data analysis Combining the test results of Example 6 and Example 3, the apparent viscosity of Example 6 is higher than that of Example 3. The analysis is as follows. The difference between Example 6 and Example 3 is that the temperature and salt-resistant agent also includes N-vinylpyrrolidone. The cyclic structure of N-vinylpyrrolidone itself can increase the viscoelasticity of the polymer molecular chain containing sulfonic acid groups, so as to improve the stability of polyacrylamide, thereby improving the temperature and salt resistance of polyacrylamide.

[0058] Specifically, combining the test results of Example 11 and Example 6, the apparent viscosity of Example 11 is higher than that of Example 6. The analysis is as follows. The difference between Example 11 and Example 6 is that betaine modifies N-vinylpyrrolidone to improve the stability of N-vinylpyrrolidone in the polymer, thereby improving the salt and salt resistance of polyacrylamide.

[0059] Specifically, combining the test results of Example 3 and Comparative Example 1, the apparent viscosity of Example 3 is higher than that of Comparative Example 1. The analysis is as follows. The difference between Example 3 and Comparative Example 1 is that the polyacrylamide contains 2-acrylamidooctanesulfonic acid, so as to improve the temperature and salt resistance of polyacrylamide through the insensitivity of sulfonic acid groups to salts.

[0060] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A quick-soluble polyacrylamide, characterized in that: The invention comprises the following raw materials in parts by weight: 10-20 parts of acrylic acid, 60-70 parts of acrylamide, 50-60 parts of dimethyldiallylammonium chloride, 40-46 parts of a heat-resistant and salt-resistant agent, 0.05-0.15 parts of an initiator, and 220-240 parts of deionized water, wherein the heat-resistant and salt-resistant agent comprises 2-acrylamidooctane sulfonic acid.

2. The instant polyacrylamide according to claim 1, characterized in that: The preparation method of 2-acrylamido octane sulfonic acid comprises the following steps: 1-octene, acrylonitrile and a polymerization inhibitor are mixed and stirred continuously, and then fuming sulfuric acid is added. After the reaction is completed, the mixture is washed and dried in sequence to obtain 2-acrylamidooctane sulfonic acid.

3. The instant polyacrylamide according to claim 2, characterized in that: The mass ratio of 1-octene, acrylonitrile and fuming sulfuric acid is 1:6:(0.9-1.1).

4. The instant polyacrylamide according to claim 2, characterized in that: The polymerization inhibitors include p-hydroxyanisole and 2,6-di-tert-butyl-p-cresol.

5. The instant polyacrylamide according to claim 1, characterized in that: The heat and salt resistant agent also includes N-vinyl pyrrolidone.

6. The instant polyacrylamide according to claim 5, characterized in that: The mass ratio of the 2-acrylamido octane sulfonic acid to N-vinyl pyrrolidone is 1:(0.82-0.88).

7. The instant polyacrylamide according to claim 5, characterized in that: The N-vinyl pyrrolidone is prepared by modification, and the modification preparation of the N-vinyl pyrrolidone comprises the following steps: N-vinyl pyrrolidone is prepared into an N-vinyl pyrrolidone aqueous solution, hydrochloric acid is added, and the mixture is stirred evenly, and then betaine is added, and the mixture is fully stirred and dried for dehydration, and then anhydrous ethanol is added, and the mixture is fully stirred, and then acetone is added, and the mixture is fully stirred and filtered and evaporated to obtain modified N-vinyl pyrrolidone.

8. The instant polyacrylamide according to claim 7, characterized in that: The mass ratio of the N-vinyl pyrrolidone to betaine is 1:(0.23-0.33).

9. The instant polyacrylamide according to claim 1, characterized in that: The initiators include potassium persulfate and sodium bisulfite.

10. A method for preparing the instant polyacrylamide as claimed in claim 1, comprising the following steps: Acrylic acid, 2-acrylamido octyl sulfonic acid and deionized water are mixed, nitrogen is introduced for protection, and the mixture is fully stirred. Then, sodium hydroxide is added to adjust the pH value, and a deionized water solution of acrylamide and dimethyldiallyl ammonium chloride is added. The temperature is then raised, and finally an initiator is added. After stirring evenly, the temperature is raised for reaction. After the reaction is completed, the product is sheared and dried to obtain polyacrylamide.

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