A green phosphorus-free corrosion and scale inhibitor

Abstract

The present invention discloses a green phosphorus-free and nitrogen-free corrosion and scale inhibitor, and the present invention relates to the technical field of energy-saving and environmental-friendly water treatment agents. This corrosion and scale inhibitor is prepared from polyaspartic acid, hydrolyzed polymaleic acid, acrylic acid / hydroxypropyl acrylate copolymer, polyepoxysuccinic acid, δ-valerolactam, sodium borate, zinc sulfate heptahydrate, and benzotriazole in specific proportions. The preparation process includes the preparation of modified polyaspartic acid, the addition of other components, the mixing of modified polyaspartic acid and other components, pH adjustment and homogenization, as well as filtration and filling, etc. The corrosion and scale inhibitor of the present invention has excellent corrosion inhibition and scale inhibition performance. The anti-corrosion inhibition efficiency of the examples is as high as 88.6%, and the scale inhibition rate ranges from 90.5% to 92.4%. Compared with the comparative examples, while providing high-efficiency corrosion and scale inhibition performance, the present invention also has the advantages of environmental protection, economy, etc., and is a green water treatment agent with great application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving and environmental-friendly water treatment agents, and particularly relates to a green phosphorus-free corrosion and scale inhibitor. Background Art

[0002] Water is the source of life and an important resource indispensable in industrial production. However, in the process of industrial production, water systems often face the problems of scaling and corrosion, which not only reduce the service life and operation efficiency of equipment, but also cause huge economic losses. To solve these problems, corrosion and scale inhibitors have emerged and have been widely used in the field of industrial water treatment.

[0003] Traditional corrosion and scale inhibitors mainly include phosphorus-containing compounds such as phosphates and organophosphonates, as well as nitrogen-containing compounds such as polyacrylamide. These compounds have good corrosion and scale inhibition effects, but at the same time, there are also some serious environmental problems. The discharge of phosphorus-containing compounds into water bodies will cause eutrophication of water bodies, leading to a large number of algae blooms and destroying the water ecological balance. Nitrogen-containing compounds will increase the total nitrogen content of water bodies, which will also cause eutrophication problems. Therefore, the development of green and environment-friendly corrosion and scale inhibitors has become a research hotspot and development trend in the current water treatment field.

[0004] In recent years, with the enhancement of environmental awareness and the increasing strictness of relevant regulations, phosphorus-free and nitrogen-free corrosion and scale inhibitors have gradually become the key research direction. At present, the main phosphorus-free corrosion and scale inhibitors include the following categories:

[0005] Polycarboxylic acid compounds

[0006] Polycarboxylic acid compounds are an important type of phosphorus-free corrosion and scale inhibitors, mainly including polyacrylic acid (PAA), polymaleic acid (PMA), polyepoxysuccinic acid (PESA), etc. These compounds chelate with metal ions through carboxyl groups to form soluble complexes, thereby playing a scale inhibition role. At the same time, carboxyl groups can also adsorb on the metal surface to form a protective film, playing a corrosion inhibition role. Polycarboxylic acid compounds have good biodegradability and are one of the most widely used green corrosion and scale inhibitors at present.

[0007] Polyamino acid compounds

[0008] Polyamino acid compounds, such as polyaspartic acid (PASP) and polyglutamic acid (PGA), are a new type of green corrosion and scale inhibitors. These compounds not only have good corrosion and scale inhibition performance, but also have excellent biodegradability and environmental friendliness. Polyamino acids act on metal ions through carboxyl groups and amino groups, which can not only chelate metal ions, but also form a protective film on the metal surface, thus realizing the dual functions of corrosion and scale inhibition.

[0009] Natural polymer compounds and their derivatives

[0010] Using natural macromolecular compounds and their derivatives as corrosion and scale inhibitors has been one of the research hotspots in recent years. Common natural macromolecules include starch, cellulose, chitosan, etc. Through chemical modification such as carboxymethylation and sulfonation, the corrosion and scale inhibition performance of these compounds can be enhanced. Natural macromolecular compounds have a wide source, low price, and good biodegradability, making them potential green corrosion and scale inhibitors.

[0011] Inorganic silicon compounds

[0012] Inorganic silicon compounds, such as silicates and metasilicates, are also an important type of phosphorus-free corrosion and scale inhibitors. These compounds play a corrosion inhibition role by forming a dense silicate protective film on the metal surface. At the same time, silicate ions can also react with metal ions such as calcium and magnesium to form silicate complexes that are not easily deposited, thus playing a scale inhibition role. Inorganic silicon compounds have good thermal stability and chemical stability and are suitable for working conditions of high temperature and high pressure.

[0013] Organic boron compounds

[0014] Organic boron compounds, such as borates and polyborates, are new types of green corrosion and scale inhibitors studied in recent years. These compounds play a corrosion inhibition role by forming a borate protective film on the metal surface. At the same time, borate ions can also react with metal ions such as calcium and magnesium to form soluble complexes, thus playing a scale inhibition role. Organic boron compounds have good environmental friendliness and can still maintain good performance under high temperature conditions.

[0015] Although phosphorus-free corrosion and scale inhibitors have significant advantages in terms of environmental friendliness, they still face some challenges in practical applications:

[0016] Insufficient performance

[0017] Compared with traditional phosphorus-containing and nitrogen-containing corrosion and scale inhibitors, the performance of phosphorus-free corrosion and scale inhibitors is still insufficient in some aspects. For example, under water quality conditions of high hardness and high alkalinity, the scale inhibition effect of phosphorus-free corrosion and scale inhibitors may be inferior to that of phosphorus-containing compounds. At the same time, on some metal materials, the corrosion inhibition effect of phosphorus-free corrosion and scale inhibitors may also be inferior to that of traditional corrosion inhibitors.

[0018] Higher cost

[0019] Some phosphorus-free corrosion and scale inhibitors, such as polyamino acid compounds, have a much higher price than traditional corrosion and scale inhibitors due to complex production processes and high raw material costs. This has limited their large-scale application to a certain extent.

[0020] Limited scope of application

[0021] Different types of phosphorus-free corrosion and scale inhibitors exhibit different performances under different water quality conditions and temperature conditions. For example, some polycarboxylic acid compounds may undergo hydrolysis under high-temperature conditions, resulting in a decline in performance. Inorganic silicon compounds may precipitate under low pH conditions, affecting their corrosion and scale inhibition effects. Therefore, how to select a phosphorus-free corrosion and scale inhibitor suitable for specific working conditions remains a challenge.

[0022] Insufficient research on synergistic effects

[0023] In practical applications, it is usually necessary to use a variety of corrosion and scale inhibitors in combination to achieve the best effect. However, the current research on the synergistic effects between phosphorus-free corrosion and scale inhibitors is not deep enough, which to a certain extent limits the improvement of their application effects.

[0024] Long-term stability needs to be improved

[0025] Some phosphorus-free corrosion and scale inhibitors, especially some natural polymer compounds, may degrade or their performance may decline during long-term use. How to improve the long-term stability of these green corrosion and scale inhibitors is one of the important directions for future research.

[0026] Facing these challenges, researchers are constantly exploring new solutions:

[0027] Developing new phosphorus-free corrosion and scale inhibitors

[0028] By molecular design and synthesizing new phosphorus-free and nitrogen-free compounds, or modifying the structures of existing compounds to improve their corrosion and scale inhibition performances. For example, by introducing specific functional groups, the adsorption ability of the compound on the metal surface can be enhanced, thereby improving the corrosion inhibition effect.

[0029] Research on compounding technology

[0030] By studying the synergistic effects between different types of phosphorus-free corrosion and scale inhibitors, developing composite formulations with more excellent performances. For example, compounding polycarboxylic acid compounds with polyamino acid compounds can, to a certain extent, make up for their respective deficiencies and achieve performance optimization.

[0031] Application of nanotechnology

[0032] Applying nanotechnology to the development of phosphorus-free corrosion and scale inhibitors can significantly improve their performances. For example, using nanomaterials as carriers can improve the dispersibility and stability of corrosion and scale inhibitors, thereby enhancing their use effects.

[0033] Research on green synthesis processes

[0034] Develop a more environmentally friendly and economical green synthesis process to reduce the production cost of phosphorus-free corrosion and scale inhibitors. For example, using biological fermentation technology to produce polyamino acid compounds can significantly reduce the production cost and improve its market competitiveness.

[0035] Development of intelligent corrosion and scale inhibition system

[0036] Combining Internet of Things and artificial intelligence technologies, develop an intelligent corrosion and scale inhibition system to achieve precise dosing and real-time monitoring of corrosion and scale inhibitors. This can not only improve the corrosion and scale inhibition effect, but also reduce the dosage of chemicals and minimize environmental impact.

[0037] Generally speaking, the development and application of phosphorus-free corrosion and scale inhibitors is a challenging but promising research field. With the increasing environmental protection requirements and continuous technological progress, green and environmentally friendly corrosion and scale inhibitors will surely play an increasingly important role in the future industrial water treatment field. Summary of the Invention

[0038] In view of this, the purpose of the present invention is to provide a green phosphorus-free corrosion and scale inhibitor. The green phosphorus-free corrosion and scale inhibitor of the present invention not only meets the increasingly stringent environmental protection requirements, but also has outstanding performance, applicability and economy, providing a new and efficient environmentally friendly solution for the industrial water treatment field.

[0039] The technical solution adopted is as follows:

[0040] A green phosphorus-free corrosion and scale inhibitor is prepared from the following raw materials in parts by weight:

[0041] Polyaspartic acid 10 - 25 parts,

[0042] Hydrolyzed polymaleic acid 8 - 18 parts,

[0043] Acrylic acid / hydroxypropyl acrylate copolymer 8 - 20 parts,

[0044] Polyepoxysuccinic acid 10 - 15 parts,

[0045] δ-Valerolactam 5 - 15 parts,

[0046] Sodium borate 2 - 8 parts,

[0047] Zinc sulfate heptahydrate 4 - 8 parts,

[0048] Benzotriazole 0.5 - 1 part.

[0049] Preferably, the green phosphorus-free corrosion and scale inhibitor is prepared from the following raw materials in parts by weight:

[0050] Polyaspartic acid 18 parts,

[0051] 12 parts of hydrolyzed polymaleic acid,

[0052] 14 parts of acrylic acid / acrylic acid hydroxypropyl ester copolymer,

[0053] 13 parts of polyepoxysuccinic acid,

[0054] 10 parts of δ-valerolactam,

[0055] 5 parts of sodium borate,

[0056] 6 parts of zinc sulfate heptahydrate,

[0057] 0.8 part of benzotriazole.

[0058] Preferably, the parameters of the polyaspartic acid are: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 。

[0059] Preferably, the parameters of the hydrolyzed polymaleic acid are: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 。

[0060] Preferably, the parameters of the acrylic acid / acrylic acid hydroxypropyl ester copolymer are: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0061] The parameters of the polyepoxysuccinic acid are: CAS No.: 1528-98-71, density: 1.15 g / cm 3 。

[0062] The parameters of the δ-valerolactam are: CAS No.: 675-20-7, density: 1.073 g / cm 3 ;

[0063] The parameters of the benzotriazole are: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 。

[0064] The green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0065] (1) Preparation of modified polyaspartic acid

[0066] Add polyaspartic acid to the reaction kettle, add 60 to 80 times the mass of deionized water and stir, the stirring speed is set at 300 rpm, and stir until completely dissolved;

[0067] Slowly add δ-valerolactam, raise the reaction temperature to 65°C - 75°C, maintain constant temperature stirring for 2h - 6h, and use a constant temperature water bath to keep the temperature stable;

[0068] Cool down to 50°C, add benzotriazole, continue stirring for 1h - 3h, cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0069] (2)Addition of other components

[0070] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer in another reaction kettle, set the stirring speed to 250 rpm, and stir evenly;

[0071] Slowly add polyepoxysuccinic acid, and continue stirring until the solution is clear and transparent to obtain a mixed solution;

[0072] (3)Mix the modified polyaspartic acid with other components

[0073] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), continuously stir at a constant temperature, set the constant temperature stirring speed to 350 rpm, the constant temperature stirring time is 30 min, and the constant temperature stirring temperature is 75°C - 90°C.

[0074] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, and continue stirring until completely dissolved without precipitation to obtain a combined solution;

[0075] (4)pH adjustment and homogenization

[0076] Adjust the pH of the combined solution in step (3) to 7.5 - 8.5 with 0.1 M sodium hydroxide solution;

[0077] Transfer the combined solution to a high-speed disperser and perform homogenization treatment at 5000 rpm for 30 min;

[0078] (5)Filtration and filling

[0079] Use a 100-mesh sieve to filter the homogenized solution in step (4) to remove insoluble substances and impurities;

[0080] Fill the filtered product into a dry, clean and sealed container, and perform corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0081] In summary, the beneficial effects of the present invention are as follows:

[0082] First, the corrosion and scale inhibitor adopts a phosphorus - and nitrogen - free formulation design, meeting the requirements of current environmental protection regulations and policies. Traditional corrosion and scale inhibitors usually contain components such as phosphates and organophosphonates. After these components are discharged into water bodies, they are prone to cause eutrophication of the water bodies, leading to excessive growth of algae and disrupting the aquatic ecological balance. By using phosphorus - and nitrogen - free compounds such as polyaspartic acid, hydrolyzed polymaleic acid, and acrylic acid / hydroxypropyl acrylate copolymer, the present invention effectively avoids this environmental problem.

[0083] Secondly, the corrosion and scale inhibitor of the present invention performs excellently in terms of performance. Through reasonable component ratios and modification technologies, this product can provide excellent corrosion inhibition and scale inhibition effects under various water quality conditions. The modification reaction of polyaspartic acid with δ - valerolactam and benzotriazole enhances its adsorption ability on the metal surface, thereby improving the corrosion inhibition performance. At the same time, other components such as polyepoxysuccinic acid and hydrolyzed polymaleic acid achieve efficient scale inhibition effects by chelating metal ions and forming a protective film.

[0084] In addition, this product has good biodegradability and will not cause long - term pollution to the environment after use. Compared with traditional phosphorus - and nitrogen - containing corrosion and scale inhibitors, the product of the present invention does not release harmful substances during the biodegradation process, so it is more environmentally friendly. This characteristic makes it particularly suitable for application scenarios with high requirements for environmental impact, such as drinking water treatment and industrial water treatment in ecologically sensitive areas.

[0085] Finally, the method of the present invention has a simple process and low cost. By optimizing the preparation process, such as homogenization treatment and pH adjustment steps, not only the consistency and stability of the product are improved, but also the production cost is reduced. This makes the product highly competitive in commercial applications and can be widely used in the circulating cooling water systems of industries such as power, petrochemical, and metallurgy, providing an efficient, economical, and environmentally friendly solution for these industries.

[0086] In summary, the present invention not only achieves a breakthrough in technology but also provides a sustainable green solution for the field of industrial water treatment. Brief Description of the Drawings

[0087] Figure 1 is the infrared spectrum diagram of modified polyaspartic acid;

[0088] Figure 2 is the XPS energy spectrum diagram of modified polyaspartic acid.

[0089] Figure 3 is the test result diagram of anti - corrosion inhibition efficiency.

[0090] Figure 4 is the scanning electron microscope image of the carbon steel surface (the scale in the figure is 100um, from top to bottom are blank control, Comparative Example 2, and Example 3).

[0091] Figure 5 It is a test result graph of the scale inhibition rate. Specific implementation manners

[0092] The present invention will be described in detail below through specific embodiments. However, the uses and purposes of these exemplary embodiments are only used to illustrate the present invention, and do not constitute any form of limitation to the actual protection scope of the present invention, nor will the protection scope of the present invention be limited thereto.

[0093] Example 1

[0094] The green phosphorus-free corrosion and scale inhibitor is prepared from the following raw materials in parts by weight:

[0095] Polyaspartic acid: 10 parts,

[0096] Hydrolyzed polymaleic acid: 18 parts,

[0097] Acrylic acid / acrylic acid hydroxypropyl ester copolymer: 8 parts,

[0098] Polyepoxysuccinic acid: 15 parts,

[0099] δ-Valerolactam: 5 parts,

[0100] Sodium borate: 8 parts,

[0101] Zinc sulfate heptahydrate: 4 parts,

[0102] Benzotriazole: 1 part.

[0103] The parameters of the polyaspartic acid: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 .

[0104] The parameters of the hydrolyzed polymaleic acid: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 .

[0105] The parameters of the acrylic acid / acrylic acid hydroxypropyl ester copolymer: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0106] The parameters of the polyepoxysuccinic acid: CAS No.: 1528-98-71, density: 1.15 g / cm 3 .

[0107] Parameters of the δ-valerolactam: CAS No.: 675-20-7, density: 1.073 g / cm 3 ;

[0108] Parameters of the benzotriazole: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 。

[0109] The green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0110] (1) Preparation of modified polyaspartic acid

[0111] Add polyaspartic acid into the reaction kettle, add deionized water with a mass 60 times that of polyaspartic acid and stir. Set the stirring speed to 300 rpm and stir until completely dissolved;

[0112] Slowly add δ-valerolactam, raise the reaction temperature to 65 °C, keep stirring at a constant temperature for 6 h, and use a constant temperature water bath to keep the temperature stable;

[0113] Cool down to 50 °C, add benzotriazole, continue stirring for 1 h, and cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0114] (2) Addition of other components

[0115] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed to 250 rpm, and stir evenly;

[0116] Slowly add polyepoxysuccinic acid and continuously stir until the solution is clear and transparent to obtain a mixed solution;

[0117] (3) Mixing the modified polyaspartic acid with other components

[0118] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), continuously stir at a constant temperature. Set the constant temperature stirring speed to 350 rpm, the constant temperature stirring time to 30 min, and the constant temperature stirring temperature to 75 °C.

[0119] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, continue stirring until completely dissolved and no precipitation appears to obtain a combined solution;

[0120] (4) pH adjustment and homogenization

[0121] Adjust the pH of the combined solution in step (3) to 7.5 with 0.1 M sodium hydroxide solution;

[0122] Transfer the combined solution to a high-speed disperser and carry out homogenization treatment at 5000 rpm for 30 min;

[0123] (5)Filtration and filling

[0124] Use a 100-mesh sieve to filter the homogenized solution in step (4) to remove insoluble substances and impurities;

[0125] Fill the filtered product into dry, clean and sealed containers, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0126] Example 2

[0127] The green phosphorus-free corrosion inhibitor and scale inhibitor is prepared from the following raw materials in parts by weight:

[0128] Polyaspartic acid 25 parts,

[0129] Hydrolyzed polymaleic acid 8 parts,

[0130] Acrylic acid / acrylic acid hydroxypropyl ester copolymer 20 parts,

[0131] Polyepoxysuccinic acid 10 parts,

[0132] δ-Valerolactam 15 parts,

[0133] Sodium borate 2 parts,

[0134] Zinc sulfate heptahydrate 8 parts,

[0135] Benzotriazole 0.5 part.

[0136] The parameters of the polyaspartic acid: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 .

[0137] The parameters of the hydrolyzed polymaleic acid: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 .

[0138] The parameters of the acrylic acid / acrylic acid hydroxypropyl ester copolymer: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0139] The parameters of the polyepoxysuccinic acid: CAS No.: 1528-98-71, density: 1.15 g / cm 3 .

[0140] Parameters of the δ-valerolactam: CAS No.: 675-20-7, density: 1.073 g / cm 3 ;

[0141] Parameters of the benzotriazole: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 .

[0142] The green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0143] (1) Preparation of modified polyaspartic acid

[0144] Add polyaspartic acid into a reaction kettle, add 80 times the mass of deionized water and stir. The stirring speed is set at 300 rpm until it is completely dissolved;

[0145] Slowly add δ-valerolactam, raise the reaction temperature to 75 °C, keep stirring at a constant temperature for 2 h, and use a constant temperature water bath to keep the temperature stable;

[0146] Cool down to 50 °C, add benzotriazole, continue to stir for 3 h, and cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0147] (2) Addition of other components

[0148] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed at 250 rpm, and stir evenly;

[0149] Slowly add polyepoxysuccinic acid, and continue to stir until the solution is clear and transparent to obtain a mixed solution;

[0150] (3) Mixing the modified polyaspartic acid with other components

[0151] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), continuously stir at a constant temperature. The constant temperature stirring speed is set at 350 rpm, and the constant temperature stirring time is 30 min. The temperature of the constant temperature stirring is 90 °C.

[0152] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, and continue to stir until it is completely dissolved without precipitation to obtain a combined solution;

[0153] (4) pH adjustment and homogenization

[0154] Adjust the pH of the combined solution in step (3) to 8.5 with 0.1 M sodium hydroxide solution;

[0155] Transfer the combined solution to a high-speed disperser and carry out homogenization treatment at 5000 rpm for 30 min;

[0156] (5)Filtration and filling

[0157] Use a 100-mesh sieve to filter the homogenized solution in step (4) to remove insoluble substances and impurities;

[0158] Fill the filtered product into dry, clean and sealed containers, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0159] Example 3

[0160] The green phosphorus-free corrosion inhibitor and scale inhibitor is prepared from the following raw materials in parts by weight:

[0161] Polyaspartic acid 18 parts,

[0162] Hydrolyzed polymaleic acid 12 parts,

[0163] Acrylic acid / acrylic acid hydroxypropyl ester copolymer 14 parts,

[0164] Polyepoxysuccinic acid 13 parts,

[0165] δ-Valerolactam 10 parts,

[0166] Sodium borate 5 parts,

[0167] Zinc sulfate heptahydrate 6 parts,

[0168] Benzotriazole 0.8 part.

[0169] The parameters of the polyaspartic acid: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 .

[0170] The parameters of the hydrolyzed polymaleic acid: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 .

[0171] The parameters of the acrylic acid / acrylic acid hydroxypropyl ester copolymer: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0172] The parameters of the polyepoxysuccinic acid: CAS No.: 1528-98-71, density: 1.15 g / cm 3 .

[0173] Parameters of the δ-valerolactam: CAS No.: 675-20-7, density: 1.073 g / cm 3 ;

[0174] Parameters of the benzotriazole: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 .

[0175] The green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0176] (1) Preparation of modified polyaspartic acid

[0177] Add polyaspartic acid into the reaction kettle, add 70 times the mass of deionized water and stir. The stirring speed is set at 300 rpm until completely dissolved;

[0178] Slowly add δ-valerolactam, raise the reaction temperature to 70 °C, keep stirring at a constant temperature for 4 h, and use a constant temperature water bath to keep the temperature stable;

[0179] Cool down to 50 °C, add benzotriazole, continue stirring for 2 h, and cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0180] (2) Addition of other components

[0181] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed at 250 rpm, and stir evenly;

[0182] Slowly add polyepoxysuccinic acid and continue stirring until the solution is clear and transparent to obtain a mixed solution;

[0183] (3) Mixing the modified polyaspartic acid with other components

[0184] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), keep stirring at a constant temperature. The constant temperature stirring speed is set at 350 rpm, and the constant temperature stirring time is 30 min. The temperature of the constant temperature stirring is 85 °C.

[0185] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, continue stirring until completely dissolved and no precipitation appears to obtain a combined solution;

[0186] (4) pH adjustment and homogenization

[0187] Adjust the pH of the combined solution in step (3) to 8 with 0.1 M sodium hydroxide solution;

[0188] Transfer the combined solution to a high-speed disperser and perform homogenization treatment at 5000 rpm for 30 min;

[0189] (5) Filtration and filling

[0190] The homogenized solution in step (4) is filtered using a 100-mesh sieve to remove insoluble substances and impurities;

[0191] The filtered product is filled into dry, clean, and sealed containers for corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0192] Comparative Example 1

[0193] The green phosphorus-free corrosion inhibitor and scale inhibitor is prepared from the following raw materials in parts by weight:

[0194] 18 parts of polyaspartic acid,

[0195] 14 parts of acrylic acid / hydroxypropyl acrylate copolymer,

[0196] 13 parts of polyepoxysuccinic acid,

[0197] 10 parts of δ-valerolactam,

[0198] 5 parts of sodium borate,

[0199] 6 parts of zinc sulfate heptahydrate,

[0200] 0.8 part of benzotriazole.

[0201] The parameters of the polyaspartic acid described: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 .

[0202] The parameters of the acrylic acid / hydroxypropyl acrylate copolymer described: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0203] The parameters of the polyepoxysuccinic acid described: CAS No.: 1528-98-71, density: 1.15 g / cm 3 .

[0204] The parameters of the δ-valerolactam described: CAS No.: 675-20-7, density: 1.073 g / cm 3 ;

[0205] The parameters of the benzotriazole described: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 .

[0206] The described green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0207] (1) Preparation of modified polyaspartic acid

[0208] Add polyaspartic acid into the reaction kettle, add deionized water with a mass 70 times that of polyaspartic acid and stir. The stirring speed is set at 300 rpm until it is completely dissolved;

[0209] Slowly add δ-valerolactam, raise the reaction temperature to 70 °C, and keep stirring at a constant temperature for 4 h. Use a constant temperature water bath to keep the temperature stable;

[0210] Cool down to 50 °C, add benzotriazole, and continue stirring for 2 h. Cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0211] (2) Addition of other components

[0212] Add the acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed at 250 rpm, and stir evenly;

[0213] Slowly add polyepoxysuccinic acid and keep stirring until the solution is clear and transparent to obtain a mixed solution;

[0214] (3) Mixing the modified polyaspartic acid with other components

[0215] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), and keep stirring at a constant temperature. The constant temperature stirring speed is set at 350 rpm, the constant temperature stirring time is 30 min, and the constant temperature stirring temperature is 85 °C.

[0216] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, and continue stirring until it is completely dissolved without precipitation to obtain a combined solution;

[0217] (4) pH adjustment and homogenization

[0218] Adjust the pH of the combined solution in step (3) to 8 with 0.1 M sodium hydroxide solution;

[0219] Transfer the combined solution to a high-speed disperser and carry out homogenization treatment at 5000 rpm for 30 min;

[0220] (5) Filtration and filling

[0221] Use a 100-mesh sieve to filter the homogenized solution in step (4) to remove insoluble substances and impurities;

[0222] Fill the filtered product into a dry, clean and sealed container, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0223] Comparative Example 2

[0224] The green phosphorus-free corrosion and scale inhibitor is prepared from the following raw materials in parts by weight:

[0225] 18 parts of polyaspartic acid,

[0226] 12 parts of hydrolyzed polymaleic acid,

[0227] 14 parts of acrylic acid / acrylic acid hydroxypropyl ester copolymer,

[0228] 13 parts of polyepoxysuccinic acid,

[0229] 5 parts of sodium borate,

[0230] 6 parts of zinc sulfate heptahydrate,

[0231] 0.8 part of benzotriazole.

[0232] The parameters of the polyaspartic acid described: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 。

[0233] The parameters of the hydrolyzed polymaleic acid described: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 。

[0234] The parameters of the acrylic acid / acrylic acid hydroxypropyl ester copolymer described: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0235] The parameters of the polyepoxysuccinic acid described: CAS No.: 1528-98-71, density: 1.15 g / cm 3 。

[0236] The parameters of the benzotriazole described: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 。

[0237] The green phosphorus-free corrosion and scale inhibitor described is prepared by the following method:

[0238] (1) Preparation of modified polyaspartic acid

[0239] Add polyaspartic acid to the reaction kettle, add 70 times the mass of deionized water and stir, the stirring speed is set at 300 rpm, and stir until completely dissolved;

[0240] Add benzotriazole and continue stirring for 2 h. Cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0241] (2) Addition of other components

[0242] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed at 250 rpm, and stir evenly;

[0243] Slowly add polyepoxysuccinic acid and continuously stir until the solution is clear and transparent to obtain a mixed solution;

[0244] (3) Mix the modified polyaspartic acid with other components

[0245] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), continuously stir at a constant temperature, set the constant temperature stirring speed at 350 rpm, the constant temperature stirring time at 30 min, and the constant temperature stirring temperature at 85 °C.

[0246] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, continue stirring until completely dissolved and no precipitate appears to obtain a combined solution;

[0247] (4) pH adjustment and homogenization

[0248] Adjust the pH of the combined solution in step (3) to 8 with 0.1 M sodium hydroxide solution;

[0249] Transfer the combined solution to a high-speed disperser and homogenize it at 5000 rpm for 30 min;

[0250] (5) Filtration and filling

[0251] Filter the homogenized solution in step (4) using a 100-mesh sieve to remove insoluble substances and impurities;

[0252] Fill the filtered product into a dry, clean and sealed container, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0253] Comparative Example 3

[0254] The green phosphorus-free corrosion inhibitor and scale inhibitor is prepared from the following raw materials in parts by weight:

[0255] 18 parts of polyaspartic acid,

[0256] 12 parts of hydrolyzed polymaleic acid,

[0257] 14 parts of acrylic acid / hydroxypropyl acrylate copolymer,

[0258] 13 parts of polyepoxysuccinic acid,

[0259] 10 parts of δ-valerolactam,

[0260] 5 parts of sodium borate,

[0261] 6 parts of zinc sulfate heptahydrate.

[0262] The parameters of the polyaspartic acid described: CAS No.: 25608-40-6, molecular weight: 133.103 g / mol, density: 1.5 ± 0.1 g / cm 3 .

[0263] The parameters of the hydrolyzed polymaleic acid: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: brownish-red transparent liquid, density: 1.18 g / cm 3 .

[0264] The parameters of the acrylic acid / hydroxypropyl acrylate copolymer: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05, appearance: light yellow transparent liquid.

[0265] The parameters of the polyepoxysuccinic acid: CAS No.: 1528-98-71, density: 1.15 g / cm 3 .

[0266] The parameters of the δ-valerolactam described: CAS No.: 675-20-7, density: 1.073 g / cm 3 .

[0267] The green phosphorus-free corrosion and scale inhibitor is prepared by the following method:

[0268] (1) Preparation of modified polyaspartic acid

[0269] Add polyaspartic acid into the reaction kettle, add 70 times the mass of deionized water and stir, the stirring speed is set at 300 rpm, and stir until completely dissolved;

[0270] Slowly add δ-valerolactam, raise the reaction temperature to 70 °C, keep stirring at a constant temperature for 4 h, use a constant temperature water bath to keep the temperature stable, and cool the reaction product to room temperature to obtain a modified polyaspartic acid solution;

[0271] (2) Addition of other components

[0272] Add hydrolyzed polymaleic acid and acrylic acid / hydroxypropyl acrylate copolymer into another reaction kettle, set the stirring speed at 250 rpm, and stir evenly;

[0273] Slowly add polyepoxysuccinic acid and continuously stir until the solution becomes clear and transparent to obtain a mixed solution;

[0274] (3)Mix the modified polyaspartic acid with other components

[0275] Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution of step (2), and continuously stir at a constant temperature. The constant temperature stirring speed is set at 350 rpm, the constant temperature stirring time is 30 min, and the constant temperature stirring temperature is 85 °C.

[0276] During the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, and continue to stir until completely dissolved without precipitation to obtain a combined solution;

[0277] (4)pH adjustment and homogenization

[0278] Use 0.1 M sodium hydroxide solution to adjust the pH of the combined solution in step (3) to 8;

[0279] Transfer the combined solution to a high-speed disperser and carry out homogenization treatment at 5000 rpm for 30 min;

[0280] (5)Filtration and filling

[0281] Use a 100-mesh sieve to filter the homogenized solution in step (4) to remove insoluble substances and impurities;

[0282] Fill the filtered product into a dry, clean and sealed container, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

[0283] Experiment

[0284] Among them, taking the product prepared in Example 3 as an example, the infrared spectrum of the modified polyaspartic acid is as Figure 1 shown, and its XPS energy spectrum is as Figure 2 shown.

[0285] Next, conduct a corrosion inhibition experiment. Immerse A3 carbon steel specimens (50 mm × 25 mm × 2 mm) with a known weight (accurate to 0.0001 g) into a beaker containing 500 mL of tap water (set up seven groups with a concentration of 400 mg / L, namely blank control, Examples 1 - 3, Comparative Examples 1 - 3), and place them at 80 °C for 72 h. Then, wash the A3 carbon steel specimens with a solution of 10 g / L hexamethylenetetramine in 3 mol / L HCl, distilled water, 60 g / L NaOH solution, distilled water and ethanol respectively. Dry the A3 specimens and weigh them, and calculate the anti-corrosion inhibition efficiency of the inhibitor respectively (refer to https: / / doi.org / 10.1071 / CH16720). As Figure 3As shown, it can be seen that the anti-corrosion inhibition efficiency of Examples 1-3 of the present invention is as high as 88.6%, while that of Comparative Example 1 is 82.1%, that of Comparative Example 2 is 67.5%, and that of Comparative Example 3 is 73.2%. At the same time, combined with Figure 4 it can be seen that the corrosion of the carbon steel surface caused by Example 3 is the mildest.

[0286] Finally, the scale inhibition performance was tested. 20.0 mL of CaCl2 solution (c = 16.7 g / L), scale inhibitor (seven groups were set with a concentration of 400 mg / L, namely blank control, Examples 1-3, Comparative Examples 1-3), 20.0 mL of borax buffer solution (pH = 9.0), and 20.0 mL of NaHCO3 solution (c = 25.2 g / L) were successively added to 250 mL of distilled water. The solution was diluted to 500.0 mL, and at this time, the Ca 2+ concentration was about 240 mg / L. Then, the solution was transferred to a conical flask for deposition experiment. It was kept at a constant temperature of 60, 70, and 80 °C for 10 hours respectively. The concentration of Ca 2+ was determined by the disodium ethylenediaminetetraacetate (EDTA) titration method, and the calculation of the scale inhibition rate referred to "doi: 10.3390 / ma12111821". As Figure 5 shown, the scale inhibition rate range of Examples 1-3 is 90.5%-92.4%, and the scale inhibition rates of Comparative Examples 1-3 are 83.0%, 63.8%, and 74.2% respectively.

[0287] The green phosphorus-free corrosion and scale inhibitor of the present invention has significant advantages in corrosion inhibition and anti-fouling, and the main reasons are as follows:

[0288] Corrosion inhibition performance

[0289] Composition design: The invention adopts components such as polyaspartic acid, δ-valerolactam, and benzotriazole. These components significantly enhance the adsorption capacity of metals by forming a protective film on the metal surface, thereby improving the corrosion inhibition performance.

[0290] Experimental results: The examples show that the anti-corrosion inhibition efficiency is as high as 88.6%, which is significantly better than the results of the comparative example experiments (such as 67.5% for Comparative Example 2).

[0291] Anti-fouling performance

[0292] Chelation and film formation: Components such as hydrolyzed polymaleic acid and polyepoxysuccinic acid effectively prevent the formation of scale by chelating metal ions and forming a protective film.

[0293] Experimental verification: The test results show that the scale inhibition rate of the examples is between 90.5% and 92.4%, which is significantly higher than that of the comparative experiments (for example, 63.8% in Comparative Example 2).

[0294] Reasons for advantages

[0295] Environmental friendliness: The invention does not contain phosphorus and nitrogen, avoiding the problem of water eutrophication caused by traditional corrosion and scale inhibitors, and meeting the requirements of environmental protection regulations.

[0296] Biodegradability: It will not cause long-term pollution to the environment after use, and is more environmentally friendly compared with traditional products.

[0297] Economy and process simplicity: By optimizing the preparation process, the production cost is reduced, and the consistency and stability of the product are improved, making it competitive in commercial applications.

[0298] At the same time, the analysis of Comparative Examples 1-3 is as follows:

[0299] According to the information provided, we can analyze the influence mechanism of the removal of different components in these three comparative examples on the corrosion and scale inhibition performance:

[0300] Comparative Example 1: Removal of hydrolyzed polymaleic acid

[0301] The removal of hydrolyzed polymaleic acid has a significant impact on the corrosion and scale inhibition performance: Hydrolyzed polymaleic acid is an excellent scale inhibitor, and its main action mechanism is: forming soluble complexes with metal ions (such as Ca 2+ , Mg 2+ ) through carboxyl groups to prevent scaling. Adsorbing at the crystal growth points, interfering with the crystallization process, and inhibiting the growth of scale crystals. Although hydrolyzed polymaleic acid mainly acts on scale inhibition, it can also form a protective film on the metal surface to synergistically improve the corrosion inhibition effect.

[0302] Comparative Example 2: Removal of δ-valerolactam

[0303] The removal of δ-valerolactam has a significant impact on the corrosion inhibition performance: δ-valerolactam is an important corrosion inhibitor, and its action mechanism includes: forming coordination bonds with the metal surface through nitrogen atoms to enhance the adsorption ability. Forming a dense protective film to block the contact between corrosive media and the metal surface. δ-valerolactam can produce a synergistic effect with polyaspartic acid to jointly improve the corrosion inhibition performance. After removal, this synergistic effect disappears, resulting in a decline in the overall performance.

[0304] Comparative Example 3: Removal of benzotriazole

[0305] The removal of benzotriazole has a certain impact on the corrosion inhibition performance:

[0306] Benzotriazole is an efficient corrosion inhibitor, and its mechanism of action includes: forming a coordination bond with the metal surface through nitrogen atoms to form a stable protective film. It has strong adsorption ability and can effectively block corrosive media. Weakening of the synergistic effect: Benzotriazole can produce a synergistic effect with other components (such as polyaspartic acid, δ-valerolactam) to improve the overall corrosion inhibition performance. After removal, this synergistic effect weakens.

[0307] In addition, δ-valerolactam enhances the corrosion inhibition performance of polyaspartic acid mainly in the following ways: Increasing adsorption ability: The nitrogen atom in δ-valerolactam can form a hydrogen bond with polyaspartic acid, improving the adsorption ability of polyaspartic acid on the metal surface, thereby enhancing the corrosion inhibition effect. Forming a protective film: δ-valerolactam can form a dense protective film on the metal surface, blocking the contact between corrosive media and the metal, playing a physical shielding role. Synergistic effect: The synergistic effect between δ-valerolactam and polyaspartic acid can further improve the corrosion inhibition performance. Benzotriazole enhances the corrosion inhibition performance of polyaspartic acid mainly through the following mechanisms: Forming a coordination bond: The three nitrogen atoms in benzotriazole can form a stable coordination bond with the metal surface, enhancing the adsorption ability and forming a dense protective film. Improving the film density: The addition of benzotriazole can improve the density of the protective film formed by polyaspartic acid, enhancing the physical shielding effect. Synergistic effect: The synergistic effect of benzotriazole with polyaspartic acid and δ-valerolactam can further enhance the overall corrosion inhibition performance.

[0308] In summary, the addition of δ-valerolactam and benzotriazole significantly improves the corrosion inhibition performance of polyaspartic acid through mechanisms such as enhancing adsorption ability, forming a dense protective film, and producing a synergistic effect. This reflects the innovation of the present invention in molecular design and modification strategies.

[0309] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or changes made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A green phosphorus-free corrosion and scale inhibitor, characterized in that, It is prepared from the following raw materials in parts by weight: 10-25 parts of polyaspartic acid, 8-18 parts of hydrolyzed polymaleic acid, 8-20 parts of acrylic acid / acrylic acid hydroxypropyl ester copolymer, 10-15 parts of polyepoxysuccinic acid, 5-15 parts of δ-valerolactam, 2-8 parts of sodium borate, 4-8 parts of zinc sulfate heptahydrate, and 0.5-1 part of benzotriazole; among them, the green phosphorus-free corrosion and scale inhibitor is prepared by the following method: (1) Preparation of modified polyaspartic acid: Add polyaspartic acid to a reaction kettle, add 60-80 times the mass of deionized water and stir, set the stirring speed to 300 rpm, and stir until completely dissolved; slowly add δ-valerolactam, raise the reaction temperature to 65°C-75°C, keep stirring at a constant temperature for 2-6 hours, and use a constant temperature water bath to keep the temperature stable; cool down to 50°C, add benzotriazole, and continue stirring for 1-3 hours, and cool the reaction product to room temperature to obtain a modified polyaspartic acid solution; (2) Addition of other components: Add hydrolyzed polymaleic acid and acrylic acid / acrylic acid hydroxypropyl ester copolymer to another reaction kettle, set the stirring speed to 250 rpm, and stir evenly; slowly add polyepoxysuccinic acid, and continue stirring until the solution is clear and transparent to obtain a mixed solution; (3) Mixing the modified polyaspartic acid with other components: Slowly pour the modified polyaspartic acid solution obtained in step (1) into the mixed solution in step (2), keep stirring at a constant temperature, set the constant temperature stirring speed to 350 rpm, the constant temperature stirring time is 30 minutes, and the constant temperature stirring temperature is 75°C-90°C; during the stirring process, add sodium borate and zinc sulfate heptahydrate in sequence, and continue stirring until completely dissolved without precipitation to obtain a combined solution; (4) pH adjustment and homogenization: Adjust the pH of the combined solution in step (3) to 7.5-8.5 with 0.1M sodium hydroxide solution; transfer the combined solution to a high-speed disperser and homogenize it at 5000 rpm for 30 minutes; (5) Filtration and filling: Filter the homogenized solution in step (4) with a 100-mesh sieve to remove insoluble substances and impurities; fill the filtered product into a dry, clean sealed container, and conduct corrosion inhibition performance and scale inhibition performance tests to ensure that the product meets the expected standards.

2. The green phosphorus-free corrosion and scale inhibitor according to claim 1, characterized in that It is prepared from the following raw materials in parts by weight: 18 parts of polyaspartic acid, 12 parts of hydrolyzed polymaleic acid, 14 parts of acrylic acid / acrylic acid hydroxypropyl ester copolymer, 13 parts of polyepoxysuccinic acid, 10 parts of δ-valerolactam, 5 parts of sodium borate, 6 parts of zinc sulfate heptahydrate, and 0.8 part of benzotriazole.

3. The green phosphorus-free corrosion and scale inhibitor according to claim 2, characterized in that, Parameters of the polyaspartic acid described: CAS No.: 25608-40-6, molecular weight: 133.103, density: 1.5 ± 0.1 g / cm 3 .

4. The green phosphorus-free corrosion and scale inhibitor according to claim 2, characterized in that Parameters of the hydrolyzed polymaleic acid: CAS No.: 26099-09-2, molecular weight: between 800 and 1000, appearance: dark red transparent liquid, density: 1.18 g / cm 3 .

5. The green phosphorus-free corrosion and scale inhibitor according to claim 2, characterized in that, Parameters of the acrylic acid / hydroxypropyl acrylate copolymer: CAS No.: 55719-33-0, molecular weight: 202.21, density: 1.15 ± 0.05 g / cm 3 , Appearance: light yellow transparent liquid.

6. The green phosphorus-free corrosion and scale inhibitor according to claim 2, wherein Parameters of the polyepoxysuccinic acid: CAS No.: 1528-98-7, density: 1.15 g / cm 3 .

7. The green phosphorus-free corrosion and scale inhibitor according to claim 2, wherein Parameters of the δ-valerolactam: CAS No.: 675-20-7, density: 1.073 g / cm 3 ; Parameters of the benzotriazole: CAS No.: 95-14-7, density: 1.3 ± 0.1 g / cm 3 .

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