Phosphorus-free environment-friendly polyaspartic acid scale inhibitor and preparation method thereof
By introducing sulfonic acid groups, benzotriazole, quaternary ammonium salts, and Schiff base structures into polyaspartic acid scale inhibitors, the problems of insufficient scale inhibition performance and bacterial growth of polyaspartic acid have been solved, realizing the application of highly efficient phosphorus-free and environmentally friendly scale inhibitors.
Patent Information
- Application Number
- CN202511123284.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-11-18
AI Technical Summary
Existing phosphorus-free scale inhibitors, such as polyaspartic acid, have poor scale inhibition performance, which can easily lead to bacterial growth and metal corrosion, making it difficult to meet the requirements for industrial water quality stability and environmental protection.
By preparing a phosphorus-free, environmentally friendly polyaspartic acid scale inhibitor, sulfonic acid groups, benzotriazole, quaternary ammonium salts, and Schiff base structures are introduced into the additive molecules to improve its interaction with scale and metal surfaces, thereby enhancing its scale inhibition and antibacterial properties.
It significantly improves the scale inhibition, antibacterial and corrosion inhibition properties of polyaspartic acid, ensuring water quality stability and metal corrosion protection, and meeting environmental protection requirements.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of scale inhibitors, and particularly relates to a phosphorus-free environment-friendly polyaspartate scale inhibitor and a preparation method thereof. BACKGROUND
[0002] In recent years, with the development of industry, the water consumption in industrial production is increasing, and calcium ions and acid ions exist widely in industrial water. Calcium ions are easy to form scale with other anions, which affects the water quality. Therefore, scale inhibitors are often used. At present, commonly used industrial scale inhibitors include inorganic phosphate, organic phosphonic acid and other phosphorus-rich scale inhibitors. Although they have excellent scale inhibition performance, the organic phosphonic acid scale inhibitors are not easy to degrade and can also cause eutrophication and deterioration of water quality. With the improvement of human environmental protection consciousness and the further strictness of environmental protection regulations, many countries have begun to limit the discharge of phosphorus.
[0003] Therefore, the phosphorus-free environment-friendly scale inhibitor has become a research focus. Polyaspartate is a new type of biodegradable and environment-friendly polymer material. Its raw material is easy to obtain and has a low price. It has good biocompatibility and does not contain phosphorus. It can play a good scale inhibition effect through complexation and solubilization, lattice distortion, condensation and dispersion, regeneration and self-detaching membrane hypothesis, and double-layer effect mechanisms. However, the single functional group of polyaspartate leads to the single performance. If the storage device of some industrial water is not cleaned for a long time, a large amount of bacteria will breed, which seriously affects the water quality. In addition, the scale inhibition performance of polyaspartate is still poorer than that of some commercial phosphorus-based scale inhibitors. In addition, the industrial water storage container is generally made of metal, which is easy to be corroded by long-term contact with water and oxygen. Therefore, the above problems need to be solved to meet the higher demand in the field of scale inhibitor technology. SUMMARY
[0004] The purpose of the present application is to overcome the defects of the prior art and provide a phosphorus-free environment-friendly polyaspartate scale inhibitor and a preparation method thereof.
[0005] The purpose of the present application can be achieved by the following technical solutions.
[0006] A preparation method of a phosphorus-free environment-friendly polyaspartate scale inhibitor comprises the following steps:
[0007] A1, poly succinimide and deionized water are mixed to form a suspension, and an additive is slowly added under stirring. The reaction is carried out at 30 DEG C for 24 hours. NaOH solution is used to adjust the pH value to 8-9 during the reaction, so as to obtain a polyaspartate scale inhibitor solution;
[0008] A2, adding hydrochloric acid solution to the polyaspartic acid scale inhibitor solution obtained in step A1, adjusting the pH value to 3-4, filtering, precipitating the filtrate with anhydrous ethanol for 3-4 times, vacuum drying, and finely grinding to obtain the phosphorus-free environment-friendly polyaspartic acid scale inhibitor.
[0009] Further, the raw materials are as follows in terms of weight parts: 60-70 parts of poly succinimide, 10-20 parts of auxiliary agent, and 65-75 parts of deionized water.
[0010] The auxiliary agent is prepared by the following steps:
[0011] S1, adding 1H-benzotriazole-1-formaldehyde and N,N-dimethylformamide (DMF) into a three-necked flask equipped with a stirring device, stirring uniformly, then adding diethylenetriamine and piperidine (condensing agent), stirring and uniformly mixing, controlling the reaction temperature to be 75°C, incubating for 4 hours, filtering after the reaction is completed, removing part of the solvent by reduced pressure distillation, and then purifying by column chromatography (using a mixed solvent of methanol / benzene as the eluent, the volume ratio of the two being 3:2), and removing the eluent by rotary evaporation to obtain the intermediate 1; the ratio of the amounts of 1H-benzotriazole-1-formaldehyde, N,N-dimethylformamide, diethylenetriamine, and piperidine is 14.7 g:50 mL:11.4 g:15 mL;
[0012] Under the action of the condensing agent, the aldehyde group on the 1H-benzotriazole-1-formaldehyde reacts with the amino group on the diethylenetriamine to form an imine group (C=N Schiff base structure), and by controlling the molar ratio of the two to be close to 1:1 and the diethylenetriamine to be slightly excessive, the intermediate 1 is obtained; the specific reaction process is as follows:
[0013] S2, mixing the intermediate 1, succinic acid, dicyclohexyl carbodiimide (DCC, dehydrating agent), and toluene in a three-necked flask equipped with a stirring device, stirring uniformly under the condition of a 40°C water bath, reacting for 65 minutes, filtering after the reaction is completed, and removing the solvent by reduced pressure distillation to obtain the intermediate 2; the ratio of the amounts of the intermediate 1, succinic acid, dicyclohexyl carbodiimide, and toluene is 23.2 g:12.6 g:20.6 g:75 mL;
[0014] The amino group on the intermediate 1 reacts with the carboxyl group on the succinic acid to form an amide, and under the action of the dehydrating agent, the reaction can be carried out under relatively mild conditions, and by controlling the molar ratio of the two to be close to 1:1 and the succinic acid to be slightly excessive, only one carboxyl group on the succinic acid participates in the reaction to obtain the intermediate 2; the specific reaction process is as follows:
[0015]
[0016] S3, in a three-necked flask equipped with a stirring device, intermediate 2, iodomethane and N,N-dimethylformamide were mixed and stirred uniformly, the reaction temperature was controlled at 85°C, and the reaction was carried out for 4 hours. After the reaction was completed, part of the solvent was removed by distillation under reduced pressure, and then the product was purified by column chromatography (the eluent was a mixture of methanol / benzene with a volume ratio of 7:4). The eluent was removed by rotary evaporation, and then the product was washed with anhydrous ethanol to obtain intermediate 3. The amount ratio of intermediate 2, iodomethane and N,N-dimethylformamide was 33.2 g:29.4 g:75 mL;
[0017] The quaternary ammonium reaction of intermediate 2 and iodomethane was carried out by adding excess iodomethane to make the reaction sufficient, and intermediate 3 was obtained. The structure of intermediate 3 is shown below:
[0018]
[0019] S4, in a three-necked flask equipped with a stirring device, intermediate 3, 2,5-diaminobenzenesulfonic acid, dicyclohexyl carbodiimide and toluene were mixed and stirred uniformly, and the reaction was carried out for 85 minutes under the condition of a 50°C water bath. After the reaction was completed, sodium hydroxide solution was added dropwise, and the temperature was maintained at 50°C for stirring for 45 minutes. Then, the product was filtered, the solvent was removed by rotary evaporation, and the product was vacuum dried to obtain the additive. The amount ratio of intermediate 3, 2,5-diaminobenzenesulfonic acid, dicyclohexyl carbodiimide, toluene and sodium hydroxide solution was 36.1 g:19.4 g:20.6 g:100 mL:75 mL;
[0020] The amidation reaction of the carboxyl group of intermediate 3 and the amino group of 2,5-diaminobenzenesulfonic acid was carried out under the action of a dehydrating agent under relatively mild conditions to obtain the additive. The specific reaction process is shown below:
[0021]
[0022] The amino group in the prepared auxiliary molecule attacks the carbonyl group in the poly succinimide structure, modifies the ring opening, and obtains poly aspartic acid; in addition, the auxiliary molecule contains a sulfonic acid group, a benzotriazole, a quaternary ammonium salt, and a Schiff base structure, wherein the sulfonic acid group has excellent salt resistance, high temperature resistance, and high valence metal ion resistance advantages, chelation occurs with the inorganic salt crystals generated by the water body, inhibits the growth of the crystals to play a scale inhibition role, and has good inhibition effect on various water scale, greatly improving the scale inhibition effect of the matrix; the introduction of benzotriazole can be adsorbed on the metal surface to generate a dense corrosion-resistant film, which can not only effectively prevent the metal from corroding, but also maintain the excellent performance of the metal itself; the quaternary ammonium salt is a common cationic surfactant, which can produce strong electrostatic interaction between the positive charge and the negative charge of the bacteria, and has strong adsorption effect on the bacteria, thereby improving the antibacterial performance of the matrix; in addition, the positively charged hydrophilic group in the quaternary ammonium salt can be adsorbed on the metal surface and synergize with the benzotriazole to further slow down the corrosion of the metal; finally, the introduction of the Schiff base structure can interact with the proteins and enzymes of the bacteria, block the synthesis of bacterial nucleotides and amino acids, and synergize with the quaternary ammonium salt to further enhance the antibacterial performance of the matrix.
[0023] It should be further pointed out that the auxiliary contains an amide group, which improves the compatibility with the matrix.
[0024] The beneficial effects of the present application are:
[0025] The poly aspartic acid scale inhibitor prepared by the reaction of poly succinimide and the auxiliary has greatly improved scale inhibition, antibacterial and corrosion inhibition performance; and the types of raw materials for synthesizing the poly aspartic acid scale inhibitor are few, which ensures the homogeneity and stability of the poly aspartic acid scale inhibitor; therefore, the poly aspartic acid scale inhibitor prepared by the present application has stable and efficient scale inhibition, antibacterial and corrosion inhibition performance, is environment-friendly and phosphorus-free, and has important application value in the field of scale inhibitor technology. DETAILED DESCRIPTION
[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.
[0027] Embodiment 1
[0028] Preparation of auxiliary:
[0029] S1. In a three-necked flask equipped with a stirrer, add 14.7 g of 1H-benzotriazole-1-carboxaldehyde and 50 mL of DMF. After stirring evenly, add 11.4 g of diethylenetriamine and 15 mL of piperidine. Stir and mix evenly. Control the reaction temperature at 75℃ and keep the reaction at this temperature for 4 hours. After the reaction is complete, filter and remove part of the solvent by vacuum distillation. Then purify by column chromatography (using a mixed solvent of methanol and benzene as the eluent, with a volume ratio of 3:2). Remove the eluent by rotary evaporation to obtain intermediate 1.
[0030] S2. In a three-necked flask equipped with a stirrer, 23.2 g of intermediate 1, 12.6 g of succinic acid, 20.6 g of dicyclohexylcarbodiimide and 75 mL of toluene were mixed and stirred until homogeneous. The mixture was reacted in a water bath at 40 °C for 65 min. After the reaction was completed, the mixture was filtered and distilled under reduced pressure to obtain intermediate 2.
[0031] S3. In a three-necked flask equipped with a stirrer, 33.2 g of intermediate 2, 29.4 g of iodomethane and 75 mL of DMF were mixed and stirred until homogeneous. The reaction temperature was controlled at 85 °C and the reaction was carried out for 4 h. After the reaction was completed, part of the solvent was removed by vacuum distillation, and then purified by column chromatography (the eluent was a mixed solvent of methanol and benzene with a volume ratio of 7:4). The eluent was removed by rotary evaporation and washed with anhydrous ethanol to obtain intermediate 3.
[0032] S4. In a three-necked flask equipped with a stirrer, 36.1 g of intermediate 3, 19.4 g of 2,5-diaminobenzenesulfonic acid, 20.6 g of DCC and 100 mL of toluene were mixed and stirred until homogeneous. The mixture was reacted in a water bath at 50 °C for 85 min. After the reaction was completed, 75 mL of sodium hydroxide solution (mass fraction 18%) was added dropwise. The mixture was stirred at 50 °C for 45 min, filtered, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain the auxiliary agent.
[0033] Example 2
[0034] Preparation aids:
[0035] S1. In a three-necked flask equipped with a stirrer, add 29.4 g of 1H-benzotriazole-1-carboxaldehyde and 100 mL of DMF. After stirring evenly, add 22.8 g of diethylenetriamine and 30 mL of piperidine. Stir and mix evenly. Control the reaction temperature at 75℃ and keep the reaction at this temperature for 4 hours. After the reaction is complete, filter and remove part of the solvent by vacuum distillation. Then purify by column chromatography (using a mixed solvent of methanol and benzene as the eluent, with a volume ratio of 3:2). Remove the eluent by rotary evaporation to obtain intermediate 1.
[0036] S2. In a three-necked flask equipped with a stirrer, 46.4 g of intermediate 1, 25.2 g of succinic acid, 41.2 g of dicyclohexylcarbodiimide and 150 mL of toluene were mixed and stirred until homogeneous. The mixture was reacted in a water bath at 40 °C for 65 min. After the reaction was completed, the mixture was filtered and distilled under reduced pressure to obtain intermediate 2.
[0037] S3. In a three-necked flask equipped with a stirrer, 66.4 g of intermediate 2, 58.8 g of iodomethane and 150 mL of DMF were mixed and stirred until homogeneous. The reaction temperature was controlled at 85 °C and the reaction was carried out for 4 h. After the reaction was completed, part of the solvent was removed by vacuum distillation, and then purified by column chromatography (the eluent was a mixed solvent of methanol and benzene with a volume ratio of 7:4). The eluent was removed by rotary evaporation and washed with anhydrous ethanol to obtain intermediate 3.
[0038] S4. In a three-necked flask equipped with a stirrer, 72.2 g of intermediate 3, 38.8 g of 2,5-diaminobenzenesulfonic acid, 41.2 g of DCC and 200 mL of toluene were mixed and stirred until homogeneous. The mixture was reacted in a water bath at 50 °C for 85 min. After the reaction was completed, 150 mL of sodium hydroxide solution (mass fraction 18%) was added dropwise. The mixture was stirred at 50 °C for 45 min, filtered, the solvent was removed by rotary evaporation, and the mixture was dried under vacuum to obtain the auxiliary agent.
[0039] Example 3
[0040] A1. Mix 60g of polysuccinimide (molecular weight 5000) and 65g of deionized water to form a suspension. Slowly add 10g of the additive prepared in Example 1 while stirring. React at 30°C for 24h. During the reaction, adjust the pH value to 8 using NaOH solution (mass fraction 28%) to obtain a polyaspartic acid scale inhibitor solution.
[0041] A2. Add hydrochloric acid solution (17% by mass) to the polyaspartic acid scale inhibitor solution obtained in step A1, adjust the pH value to 3, filter, precipitate the filtrate with anhydrous ethanol 3 times, vacuum dry, grind finely, and obtain phosphorus-free environmentally friendly polyaspartic acid scale inhibitor.
[0042] Example 4
[0043] A1. Mix 65g of polysuccinimide (molecular weight 6000) and 70g of deionized water to form a suspension. Slowly add 15g of the additive prepared in Example 2 while stirring. React at 30°C for 24h. During the reaction, adjust the pH value to 9 using NaOH solution (mass fraction 28%) to obtain a polyaspartic acid scale inhibitor solution.
[0044] A2. Add hydrochloric acid solution (17% by mass) to the polyaspartic acid scale inhibitor solution obtained in step A1, adjust the pH value to 4, filter, precipitate the filtrate with anhydrous ethanol 4 times, vacuum dry, grind finely, and obtain phosphorus-free environmentally friendly polyaspartic acid scale inhibitor.
[0045] Example 5
[0046] A1. Mix 70g of polysuccinimide (molecular weight 7000) and 75g of deionized water to form a suspension. Slowly add 20g of the additive prepared in Example 2 while stirring. React at 30°C for 24h. During the reaction, adjust the pH value to 9 using NaOH solution (mass fraction 28%) to obtain a polyaspartic acid scale inhibitor solution.
[0047] A2. Add hydrochloric acid solution (17% by mass) to the polyaspartic acid scale inhibitor solution obtained in step A1, adjust the pH value to 4, filter, precipitate the filtrate with anhydrous ethanol 4 times, vacuum dry, grind finely, and obtain phosphorus-free environmentally friendly polyaspartic acid scale inhibitor.
[0048] Comparative Example
[0049] We use commercially available industrial-grade polyaspartic acid water treatment scale inhibitor produced by Wuhan Jixin Yibang Biotechnology Co., Ltd.
[0050] The following performance tests were conducted on Examples 3-5 and the comparative example (all test dosages were 10 mg / L):
[0051] The scale inhibition performance of water treatment agents was determined using the national standard GB / T 16632-2008 "Determination of scale inhibition performance of water treatment agents - calcium carbonate deposition method".
[0052] The scale inhibition performance of water treatment agents was determined according to the national standard GB / T 22626-2008 "Determination of scale inhibition performance of water treatment agents - calcium phosphate deposition method".
[0053] The corrosion inhibition rate of carbon steel was determined using the national standard GB / T 18175-2000 "Determination of Corrosion Inhibition Performance of Water Treatment Agents - Rotary Plating Method".
[0054] The static sterilization test of heterotrophic bacteria was conducted using the "Static Sterilization Test of Heterotrophic Bacteria" from the "Analysis and Test Methods for Cooling Water" compiled by the Production Department and Development Department of China Petroleum & Chemical Corporation. The sterilization effect before and after 24 hours was tested.
[0055] The measurement results are shown in the table below:
[0056]
[0057] As shown in the table above, the polyaspartic acid scale inhibitor prepared by this invention has higher scale inhibition, antibacterial and corrosion inhibition properties than the comparative example. It also has strong scale inhibition properties against Ca3(PO4)2, and its performance is stable, phosphorus-free and environmentally friendly. It has important application value in the field of scale inhibitor technology.
[0058] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0059] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.
Claims
1. A method for preparing a phosphorus-free, environmentally friendly polyaspartic acid scale inhibitor, characterized in that, Includes the following steps: A1. Mix polysuccinimide and deionized water to form a suspension. Slowly add the additive while stirring. React at 30°C for 24 hours. During the reaction, use NaOH solution to adjust the pH value to 8-9 to obtain a polyaspartic acid scale inhibitor solution. A2. Add hydrochloric acid solution to the polyaspartic acid scale inhibitor solution obtained in step A1, adjust the pH value to 3-4, filter, precipitate the filtrate with anhydrous ethanol, vacuum dry, grind finely, and obtain phosphorus-free environmentally friendly polyaspartic acid scale inhibitor.
2. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 1, characterized in that, The raw materials are as follows by weight: 60-70 parts polysuccinimide, 10-20 parts additives, and 65-75 parts deionized water.
3. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 1, characterized in that, The auxiliary agent is prepared by the following steps: S1. After stirring 1H-benzotriazole-1-carboxaldehyde and N,N-dimethylformamide evenly, diethylenetriamine and piperidine are added and stirred evenly. The mixture is kept at 75°C for 4 hours. After the reaction is complete, the mixture is filtered, distilled under reduced pressure, purified by column chromatography, and rotary evaporated to obtain intermediate 1. S2. Mix intermediate 1, succinic acid, dicyclohexylcarbodiimide and toluene and stir until homogeneous. React at 40°C for 65 min. After the reaction is complete, filter and distill under reduced pressure to obtain intermediate 2. S3. Mix intermediate 2, iodomethane and N,N-dimethylformamide evenly and react at 85°C for 4 hours. After the reaction is complete, distill under reduced pressure, purify by column chromatography, rotary evaporate, and wash with anhydrous ethanol to obtain intermediate 3. S4. Mix intermediates 3, 2,5-diaminobenzenesulfonic acid, dicyclohexylcarbodiimide and toluene and stir until homogeneous. React at 50°C for 85 min. After the reaction is complete, add sodium hydroxide solution dropwise, stir at 50°C for 45 min, filter, rotary evaporate, and vacuum dry to obtain the auxiliary agent.
4. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 3, characterized in that, In step S1, the ratio of the amounts of 1H-benzotriazole-1-carboxaldehyde, N,N-dimethylformamide, diethylenetriamine, and piperidine is 14.7 g: 50 mL: 11.4 g: 15 mL.
5. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 3, characterized in that, In step S2, the ratio of intermediate 1, succinic acid, dicyclohexylcarbodiimide, and toluene is 23.2 g: 12.6 g: 20.6 g: 75 mL.
6. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 3, characterized in that, In step S3, the ratio of intermediate 2, iodomethane, and N,N-dimethylformamide is 33.2 g: 29.4 g: 75 mL.
7. The preparation method of a phosphorus-free environmentally friendly polyaspartic acid scale inhibitor according to claim 3, characterized in that, In step S4, the ratio of intermediate 3, 2,5-diaminobenzenesulfonic acid, dicyclohexylcarbodiimide, toluene, and sodium hydroxide solution is 36.1g:19.4g:20.6g:100mL:75mL.
8. A phosphorus-free, environmentally friendly polyaspartic acid scale inhibitor, characterized in that, Prepared according to the method according to any one of claims 1-7.