Environment-friendly phosphorus-free corrosion and scale inhibitor and preparation method thereof

Abstract

The application discloses an environment-friendly phosphorus-free corrosion and scale inhibitor, and belongs to the technical field of environmental protection. The environment-friendly phosphorus-free corrosion and scale inhibitor comprises the following raw materials: a polyquaternary ammonium salt scale inhibiting component, a carboxyl-terminated branched polyether and a water-soluble inorganic zinc salt. The polyquaternary ammonium salt scale inhibiting component is a copolymer of methacryloxyethyl trimethyl ammonium chloride, a sulfonic acid group-containing vinyl monomer and an unsaturated carboxyl monomer. The carboxyl-terminated branched polyether is obtained by taking quinolinyl methanol as a core, propylene oxide as a reaction monomer, ring-opening polymerization to obtain a hydroxyl-terminated branched polyether, and then modification by succinic anhydride end-capping. In the polyquaternary ammonium salt scale inhibiting component, the introduction of quaternary ammonium salt groups and sulfonic acid groups helps to improve the dispersibility and electrostatic adsorption capacity, thereby significantly enhancing the corrosion and scale inhibition performance. The carboxyl-terminated branched polyether can be effectively adsorbed on the surface of metal materials. The two components can form a more compact protective film, improve the inhibition capacity to scales and enhance the high-temperature stability of the system.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology, specifically relating to an environmentally friendly phosphorus-free corrosion and scale inhibitor and its preparation method. Background Technology

[0002] In industrial production, the consumption of cooling water is enormous. The use of circulating cooling water conservancy saves water resources and reduces production costs. However, as the concentration of cooling water increases, inorganic ions and bacteria accumulate, leading to problems such as scaling, corrosion, and the growth of algae and slime. In some areas of my country with corrosive water, this damage to equipment is even more severe. Therefore, adding appropriate amounts of water treatment agents with corrosion and scale inhibition functions to the circulating water system is a commonly used method.

[0003] In traditional circulating water treatment technologies, phosphorus-based scale inhibitors are widely used due to their high efficiency and stable scale inhibition performance. These scale inhibitors mainly include inorganic phosphates, organic phosphates (such as HEDP and ATMP), and phosphate esters. Their mechanism of action is primarily through chelating or complexing hardness ions such as calcium and magnesium in the water, altering the crystal lattice structure, and inhibiting the precipitation and deposition of slightly soluble salts such as calcium carbonate and calcium sulfate. This protects the heat exchange surface, extends equipment life, and maintains efficient system operation.

[0004] However, the long-term and extensive use of phosphorus-based scale inhibitors has also brought significant environmental problems. Phosphorus, as a key limiting factor for eutrophication, easily enters natural water bodies with discharged wastewater, promoting abnormal algal growth, disrupting the aquatic ecological balance, and causing environmental disasters such as red tides and algal blooms. With the tightening of environmental policies and the deepening promotion of green and sustainable development concepts, the application of phosphorus-based scale inhibitors has been strictly limited, making the development of environmentally friendly alternative technologies an urgent need for the industry.

[0005] Phosphorus-free scale inhibitors utilize non-phosphorus chemical components, such as polymers like polyacrylic acid (PAA), polymaleic acid (PMA), hydrolyzed polymaleic anhydride (HPMA), polyepoxysuccinic acid (PESA), and polyaspartic acid (PASP), as well as natural extracts like starch and cellulose derivatives. These substances stabilize and disperse scale-forming ions through effects such as dispersion, lattice distortion, electrostatic repulsion, and steric hindrance, effectively preventing scale formation and deposition.

[0006] Despite the significant advantages of phosphorus-free scale inhibitors in reducing phosphorus pollution, they still face numerous challenges in practical industrial applications. For example, under conditions of high hardness, high alkalinity, or high temperature water, the scale inhibition efficiency of some phosphorus-free agents is still inferior to that of traditional phosphorus-based products; some polymer-based phosphorus-free agents have problems with poor degradability or bioaccumulation potential.

[0007] Therefore, driven by increasingly stringent environmental protection requirements and continuous advancements in water treatment technology, the development of novel phosphorus-free scale inhibitors that are efficient, economical, and biodegradable has become an important research direction in the field of industrial water treatment, with significant environmental benefits and broad market prospects. Summary of the Invention

[0008] The purpose of this invention is to provide an environmentally friendly phosphorus-free corrosion and scale inhibitor and its preparation method, so as to solve the problem of poor scale inhibition effect of phosphorus-free corrosion and scale inhibitors.

[0009] The objective of this invention can be achieved through the following technical solutions:

[0010] This embodiment provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor comprising the following raw materials: a polyquaternary ammonium salt scale inhibitor component, a carboxyl-terminated branched polyether, and a water-soluble inorganic zinc salt. The mass ratio of the polyquaternary ammonium salt scale inhibitor component, the carboxyl-terminated branched polyether, and the water-soluble inorganic zinc salt is 1:0.3-1:0.2-0.6. The polyquaternary ammonium salt scale inhibitor component is a copolymer of methacryloyloxyethyltrimethylammonium chloride, a vinyl monomer containing sulfonic acid groups, and an unsaturated carboxyl monomer. The carboxyl-terminated branched polyether is obtained by ring-opening polymerization using quinolinyl methanol as the core and glycidol as the reactive monomer, followed by end-capping with succinic anhydride.

[0011] In some possible implementations, the sulfonic acid-containing vinyl monomer is one of sodium styrene sulfonate and 2-acrylamide-2-methylpropanesulfonic acid.

[0012] In some possible implementations, the unsaturated carboxyl monomer is at least one of itaconic acid, maleic acid, and acrylic acid.

[0013] In some possible implementations, the water-soluble inorganic zinc salt is one of zinc chloride, zinc sulfate, and zinc nitrate.

[0014] In some possible implementations, the polyquaternary ammonium salt scale inhibitor component is prepared by the following steps:

[0015] Methacryloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and sodium bisulfite were added to water. The temperature was set to 78-80℃. Ammonium persulfate was added, followed by unsaturated carboxyl monomers. After the addition was complete, the temperature was kept constant, and the reaction was continued with stirring for 3-4 hours to obtain a polyquaternary ammonium salt scale inhibitor component.

[0016] In some possible implementations, the molar ratio of methacryloyloxyethyltrimethylammonium chloride, the sulfonic acid-containing vinyl monomer, and the unsaturated carboxyl monomer is 1-2:1-2:4.

[0017] The total amount of monomers refers to the total molar amount of methacryloyloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and unsaturated carboxyl monomers; the molar ratio of the total amount of monomers, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15-0.2.

[0018] In some possible implementations, the terminal carboxyl-branched polyether is prepared by the following steps:

[0019] Under nitrogen protection, quinolinyl methanol and potassium methoxide were added to dioxane, and the temperature was raised to 90-95℃. Glycidol was added, and the reaction was stirred for 4-5 hours after the addition was complete. After the reaction was completed, hydrochloric acid was added to adjust the pH of the system to 5-6, and acetone was added to precipitate the polyether, which was then hydroxyl-terminated. The hydroxyl-terminated polyether was added to N,N-dimethylformamide, succinic anhydride and sulfuric acid were added, and the temperature was set at 65-70℃. The reaction was stirred for 3-4 hours. After the reaction was completed, the polyether was precipitated with ice-cold diethyl ether, washed and dried to obtain carboxyl-terminated branched polyether.

[0020] In some possible implementations, quinolinylmethanol is one of 2-quinolinylmethanol, 6-quinolinylmethanol, and 8-quinolinylmethanol.

[0021] In some possible implementations, the amount of potassium methoxide added is 0.01% of the total mass of quinolinyl methanol and glycidol; the molar ratio of quinolinyl methanol to glycidol is 1:18-20;

[0022] The ratio of terminal hydroxyl branched polyether, succinic anhydride, and sulfuric acid is 5-5.5g:0.08mol:0.07g.

[0023] The second aspect of this application provides a method for preparing the above-mentioned environmentally friendly phosphorus-free corrosion and scale inhibitor, comprising the following steps: adding raw materials to water and stirring to mix them, thereby obtaining the environmentally friendly phosphorus-free corrosion and scale inhibitor.

[0024] The beneficial effects of this invention are:

[0025] This invention provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor, comprising a polyquaternary ammonium salt scale inhibitor component, a carboxyl-terminated branched polyether, and a water-soluble inorganic zinc salt. The polyquaternary ammonium salt scale inhibitor component is a copolymer of methacryloyloxyethyltrimethylammonium chloride, a vinyl monomer containing sulfonic acid groups, and an unsaturated carboxyl monomer. The carboxyl-terminated branched polyether is obtained by ring-opening polymerization of quinolinyl methanol as the core and propylene oxide as the reactant monomer to obtain a hydroxyl-terminated branched polyether, which is then end-capped with succinic anhydride to obtain the carboxyl-terminated branched polyether.

[0026] In the aforementioned polyquaternary ammonium salt scale inhibitor component, the introduction of quaternary ammonium salt groups and sulfonic acid groups helps to improve its dispersibility and electrostatic adsorption capacity, thereby significantly enhancing its corrosion inhibition and scale inhibition performance. Carboxyl-terminated branched polyethers can effectively adsorb onto the surface of metallic materials. On the one hand, their branched structure endows the molecules with higher steric hindrance and thermal stability; on the other hand, they can block corrosion ions (such as C...) The accumulation of these substances on the metal surface delays the occurrence of localized corrosion, thereby achieving the function of corrosion inhibition.

[0027] There is a synergistic effect between polyquaternary ammonium salt scale inhibitors and carboxyl-terminated branched polyethers. The polyquaternary ammonium salt scale inhibitors can prevent scale particle aggregation through charge neutralization and dispersion, while the carboxyl-terminated branched polyethers, with their branched structure and terminal carboxyl groups, enhance the chelation and crystal distortion effects on calcium ions. The combination of the two can form a denser protective film, while improving the ability to inhibit scale and enhancing the high-temperature stability of the system. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] The following is a detailed description of the embodiments of this application.

[0030] The first aspect of this application provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor comprising the following raw materials: a polyquaternary ammonium salt scale inhibitor component, a carboxyl-terminated branched polyether, and a water-soluble inorganic zinc salt, wherein the mass ratio of the polyquaternary ammonium salt scale inhibitor component, the carboxyl-terminated branched polyether, and the water-soluble inorganic zinc salt is 1:0.3-1:0.2-0.6. With the increase of the amount of carboxyl-terminated branched polyether, the chelating ability of the carboxyl groups for calcium ions is enhanced, effectively inhibiting the growth and deposition of calcium scale crystals. Simultaneously, its polyether segments have good water solubility and a certain calcium dissolving ability, further improving scale inhibition performance. This invention uses a quinoline structure with corrosion inhibition function as the molecular core of the branched polyether, introducing more functional groups distributed on the periphery through branching polymerization, increasing the effective specific surface area and adsorption activity of the molecule, thereby fully leveraging the synergistic effect of scale inhibition and corrosion inhibition. Furthermore, the branched structure has superior thermal stability compared to linear polymers, making it suitable for complex water quality environments such as high temperature and high hardness.

[0031] The polyquaternary ammonium salt scale inhibitor is a copolymer of methacryloyloxyethyltrimethylammonium chloride, a vinyl monomer containing sulfonic acid groups, and an unsaturated carboxyl monomer. The carboxyl-terminated branched polyether is obtained by ring-opening polymerization of quinolinyl methanol as the core and glycidol as the reactive monomer, and then end-capped with succinic anhydride to obtain the carboxyl-terminated branched polyether.

[0032] In some specific embodiments, the raw materials also include ascorbic acid, the amount of which is 3% to 5% of the mass of the polyquaternary ammonium salt scale inhibitor component. The strong reducing properties of ascorbic acid allow it to act as an antioxidant, protecting the raw material components and extending the shelf life and effective period of the entire formulation. Ascorbic acid chelates scale ions and zinc ions, assisting in scale inhibition and stabilizing zinc salts. However, ascorbic acid itself is acidic; excessive addition can lower the pH of the water, potentially promoting corrosion. Therefore, the amount added should not be excessive. When used in conjunction with the polyquaternary ammonium salt scale inhibitor component, it stabilizes the pH and fully utilizes its scale inhibition effect.

[0033] In some specific embodiments, the vinyl monomer containing sulfonic acid groups is one of sodium styrene sulfonate and 2-acrylamide-2-methylpropanesulfonic acid.

[0034] In some specific embodiments, the unsaturated carboxyl monomer is at least one of itaconic acid, maleic acid, and acrylic acid.

[0035] In some specific embodiments, the water-soluble inorganic zinc salt is one of zinc chloride, zinc sulfate, and zinc nitrate.

[0036] In some specific embodiments, the polyquaternary ammonium salt scale inhibitor component is prepared by the following steps:

[0037] Methacryloxyethyltrimethylammonium chloride, a vinyl monomer containing sulfonic acid groups, and sodium bisulfite were added to water at a temperature of 78-80℃. Ammonium persulfate was then added, followed by an unsaturated carboxyl monomer. After the addition was complete, the temperature was kept constant, and the reaction was continued with stirring for 3-4 hours to obtain a polyquaternary ammonium salt scale inhibitor. The quaternary ammonium salt groups can adsorb onto negatively charged metal surfaces through positive charge to form a protective film, while the sulfonic acid groups effectively inhibit the formation and deposition of scale such as calcium carbonate. Due to their strong positive charge, the quaternary ammonium salt groups preferentially adsorb onto negatively charged metal surfaces or scale microcrystals, forming an initial protective film that provides a basis for subsequent zinc complexation and dispersion, indirectly ensuring the effective concentration and activity of zinc ions. In other words, the introduction of quaternary ammonium salt groups is beneficial for improving the stability of zinc ions.

[0038] In some specific embodiments, the molar ratio of methacryloyloxyethyltrimethylammonium chloride, the sulfonic acid-containing vinyl monomer, and the unsaturated carboxyl monomer is 1-2:1-2:4.

[0039] The total amount of monomers refers to the total molar amount of methacryloyloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and unsaturated carboxyl monomers; the molar ratio of the total amount of monomers, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15-0.2.

[0040] The synthesis of carboxyl-terminated branched polyethers begins with quinolinylmethanol, a nitrogen-containing bicyclic compound with high electron density, which enhances its adsorption capacity on metal surfaces. Carboxyl-terminated branched polyethers exhibit good water solubility, and their nitrogen atoms and carboxyl groups effectively adsorb onto metal surfaces. On one hand, their branched structure imparts higher steric hindrance and thermal stability; on the other hand, they can block corrosion ions (such as C...) The accumulation of these substances on the metal surface delays the occurrence of localized corrosion, thereby achieving the function of corrosion inhibition.

[0041] In some specific embodiments, the carboxyl-terminated branched polyether is prepared by the following steps:

[0042] Under nitrogen protection, quinolinyl methanol and potassium methoxide were added to dioxane, and the temperature was raised to 90-95℃. Glycidol was added, and the reaction was stirred for 4-5 hours after the addition was complete. After the reaction was completed, hydrochloric acid was added to adjust the pH of the system to 5-6, and acetone was added to precipitate the polyether, which was then hydroxyl-terminated. The hydroxyl-terminated polyether was added to N,N-dimethylformamide, succinic anhydride and sulfuric acid were added, and the temperature was set at 65-70℃. The reaction was stirred for 3-4 hours. After the reaction was completed, the polyether was precipitated with ice-cold diethyl ether, washed and dried to obtain carboxyl-terminated branched polyether.

[0043] In some specific embodiments, quinolinylmethanol is one of 2-quinolinylmethanol, 6-quinolinylmethanol, and 8-quinolinylmethanol.

[0044] In some specific embodiments, the amount of potassium methoxide added is 0.01% of the total mass of quinolinyl methanol and glycidol; the molar ratio of quinolinyl methanol to glycidol is 1:18-20;

[0045] The ratio of terminal hydroxyl branched polyether, succinic anhydride, and sulfuric acid is 5-5.5g:0.08mol:0.07g.

[0046] With the increase of the amount of carboxyl-terminated branched polyether, the carboxyl group has a stronger chelating ability for calcium ions, which is beneficial to inhibiting crystal growth. Moreover, the polyether structure in the carboxyl-terminated branched polyether has a certain calcium-dissolving ability, further improving the scale inhibition effect. This invention uses the quinoline structure with corrosion inhibition effect as the starting point of the branching structure. The introduced branching result allows more functional groups to be distributed on the periphery, increasing the effective internal specific area of ​​the molecule and enhancing the adsorption performance. This allows the scale inhibitor to fully exert its scale inhibition properties. Furthermore, the carboxyl-terminated branched polyether with the branched structure has better high-temperature resistance than branched scale inhibitors and can better cope with complex processing environments.

[0047] The second aspect of this application provides a method for preparing the above-mentioned environmentally friendly phosphorus-free corrosion and scale inhibitor, comprising the following steps: adding raw materials to water and stirring to mix, thereby obtaining the environmentally friendly phosphorus-free corrosion and scale inhibitor.

[0048] The following is a detailed description with reference to specific examples.

[0049] Example 1

[0050] This embodiment provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor comprising the following raw materials: polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt, wherein the mass ratio of the polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt is 1:0.3:0.2.

[0051] The polyquaternary ammonium salt scale inhibitor component is prepared through the following steps:

[0052] Methacryloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and sodium bisulfite were added to water, the temperature was set to 80°C, ammonium persulfate was added, and then unsaturated carboxyl monomers were added. After the addition was completed, the temperature was kept constant and the reaction was continued to be stirred for 4 hours to obtain a polyquaternary ammonium salt scale inhibitor component.

[0053] The vinyl monomer containing sulfonic acid groups is 2-acrylamido-2-methylpropanesulfonic acid. The unsaturated carboxyl monomer is itaconic acid. The water-soluble inorganic zinc salt is zinc chloride. The molar ratio of methacryloyloxyethyltrimethylammonium chloride, the vinyl monomer containing sulfonic acid groups, and the unsaturated carboxyl monomer is 1:1:4. The molar ratio of the total amount of monomers, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15.

[0054] The carboxyl-terminated branched polyether is prepared through the following steps:

[0055] Under nitrogen protection, quinolinylmethanol and potassium methoxide were added to dioxane, the temperature was raised to 90°C, and glycidol was added. After the addition was complete, the reaction was stirred for another 5 hours. After the reaction was complete, hydrochloric acid was added to adjust the pH to 6, and acetone was added to precipitate the polyether, yielding hydroxyl-terminated branched polyether. The hydroxyl-terminated branched polyether was then added to N,N-dimethylformamide, along with succinic anhydride and sulfuric acid. The temperature was set at 70°C, and the reaction was stirred for 4 hours. After the reaction was complete, the polyether was precipitated with ice-cold diethyl ether, washed, and dried to obtain carboxyl-terminated branched polyether. The quinolinylmethanol was 2-quinolinylmethanol.

[0056] The amount of potassium methoxide added is 0.01% of the total mass of quinolinyl methanol and glycidol; the molar ratio of quinolinyl methanol to glycidol is 1:20; the ratio of terminal hydroxyl branched polyether, succinic anhydride and sulfuric acid is 5g:0.08mol:0.07g.

[0057] The raw materials are added to water and stirred to obtain an environmentally friendly phosphorus-free corrosion and scale inhibitor.

[0058] Example 2

[0059] This embodiment provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor comprising the following raw materials: polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt, wherein the mass ratio of the polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt is 1:0.5:0.4.

[0060] The polyquaternary ammonium salt scale inhibitor component is the same as in Example 1; the carboxyl-terminated branched polyether is the same as in Example 1, and the remaining raw materials and preparation process are the same as in Example 1.

[0061] Example 3

[0062] This embodiment provides an environmentally friendly, phosphorus-free corrosion and scale inhibitor comprising the following raw materials: polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt, wherein the mass ratio of the polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt is 1:1:0.6.

[0063] The polyquaternary ammonium salt scale inhibitor component is the same as in Example 1; the carboxyl-terminated branched polyether is the same as in Example 1, and the remaining raw materials and preparation process are the same as in Example 1.

[0064] Example 4

[0065] The difference between this embodiment and Example 1 is that the polyquaternary ammonium salt scale inhibitor component is different, while the other raw materials and preparation process remain the same as in Example 1.

[0066] The polyquaternary ammonium salt scale inhibitor component is prepared through the following steps:

[0067] Methacryloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and sodium bisulfite were added to water, the temperature was set to 80°C, ammonium persulfate was added, and then unsaturated carboxyl monomers were added. After the addition was completed, the temperature was kept constant and the reaction was continued to be stirred for 4 hours to obtain a polyquaternary ammonium salt scale inhibitor component.

[0068] The vinyl monomer containing a sulfonic acid group is 2-acrylamido-2-methylpropanesulfonic acid. The unsaturated carboxyl monomers are itaconic acid and acrylic acid in a molar ratio of 1:1. The water-soluble inorganic zinc salt is zinc chloride.

[0069] The molar ratio of methacryloyloxyethyltrimethylammonium chloride, sulfonic acid-containing vinyl monomer, and unsaturated carboxyl monomer is 1:1:4. The molar ratio of the total monomer content, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15.

[0070] Example 5

[0071] The difference between this embodiment and Example 1 is that the polyquaternary ammonium salt scale inhibitor component is different, while the other raw materials and preparation process remain the same as in Example 1.

[0072] The polyquaternary ammonium salt scale inhibitor component is prepared through the following steps:

[0073] Methacryloxyethyltrimethylammonium chloride, vinyl monomers containing sulfonic acid groups, and sodium bisulfite were added to water, the temperature was set to 80°C, ammonium persulfate was added, and then unsaturated carboxyl monomers were added. After the addition was completed, the temperature was kept constant and the reaction was continued to be stirred for 4 hours to obtain a polyquaternary ammonium salt scale inhibitor component.

[0074] The vinyl monomer containing sulfonic acid groups is sodium styrene sulfonate. The unsaturated carboxyl monomer is itaconic acid. The water-soluble inorganic zinc salt is zinc chloride. The molar ratio of methacryloyloxyethyltrimethylammonium chloride, the vinyl monomer containing sulfonic acid groups, and the unsaturated carboxyl monomer is 1:1:4. The molar ratio of the total amount of monomers, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15.

[0075] Example 6

[0076] The difference between this embodiment and Example 1 is that the terminal carboxyl branched polyether is different, while the other raw materials and preparation process remain the same as in Example 1.

[0077] Carboxyl-terminated branched polyethers are prepared by the following steps:

[0078] Under nitrogen protection, quinolinylmethanol and potassium methoxide were added to dioxane, the temperature was raised to 90°C, and glycidol was added. After the addition was complete, the reaction was stirred for another 5 hours. After the reaction was complete, hydrochloric acid was added to adjust the pH to 6, and acetone was added to precipitate the polyether, yielding hydroxyl-terminated branched polyether. The hydroxyl-terminated branched polyether was then added to N,N-dimethylformamide, along with succinic anhydride and sulfuric acid. The temperature was set at 70°C, and the reaction was stirred for 4 hours. After the reaction was complete, the polyether was precipitated with ice-cold diethyl ether, washed, and dried to obtain carboxyl-terminated branched polyether. The quinolinylmethanol was 6-quinolinylmethanol.

[0079] The amount of potassium methoxide added is 0.01% of the total mass of quinolinyl methanol and glycidol; the molar ratio of quinolinyl methanol to glycidol is 1:20; the ratio of terminal hydroxyl branched polyether, succinic anhydride and sulfuric acid is 5g:0.08mol:0.07g.

[0080] Example 7

[0081] Compared with Example 1, this embodiment also includes ascorbic acid as a raw material, and the amount of ascorbic acid added is 4% of the mass of the polyquaternary ammonium salt scale inhibitor component. The remaining raw materials and preparation process are the same as in Example 1.

[0082] Example 8

[0083] Compared with Example 2, this embodiment also includes ascorbic acid as a raw material, and the amount of ascorbic acid added is 4% of the mass of the polyquaternary ammonium salt scale inhibitor component. The remaining raw materials and preparation process are the same as in Example 2.

[0084] Comparative Example 1

[0085] Compared with Example 1, this comparative example does not add terminal carboxyl branched polyether, but the other raw materials and preparation process are the same as in Example 1.

[0086] Comparative Example 2

[0087] This comparative example differs from Example 4 in that the polyquaternary ammonium salt scale inhibitor component is replaced with a copolymer prepared by the following steps:

[0088] Vinyl monomers containing sulfonic acid groups and sodium bisulfite were added to water, the temperature was set to 80°C, ammonium persulfate was added, and then unsaturated carboxyl monomers were added. After the addition was completed, the temperature was kept constant and the reaction was continued to be stirred for 4 hours to obtain polyquaternary ammonium salt scale inhibitor components.

[0089] The vinyl monomer containing sulfonic acid groups is 2-acrylamido-2-methylpropanesulfonic acid. The unsaturated carboxyl monomers are itaconic acid and acrylic acid in a molar ratio of 1:1. The water-soluble inorganic zinc salt is zinc chloride. The molar ratio of the vinyl monomer containing sulfonic acid groups to the unsaturated carboxyl monomers is 1:2. The molar ratio of the total monomers, sodium bisulfite, and ammonium persulfate is 7:0.3:0.15.

[0090] The remaining raw materials and preparation process are the same as in Example 4.

[0091] Comparative Example 3

[0092] Compared with Example 1, this comparative example does not add carboxyl-terminated branched polyether, and replaces the polyquaternary ammonium salt scale inhibitor component with the copolymer prepared in Comparative Example 2. The remaining raw materials and preparation process are the same as in Example 1.

[0093] Comparative Example 4

[0094] Compared with Example 1, the comparative example has a mass ratio of 1:2:0.6 for the polyquaternary ammonium salt scale inhibitor, the carboxyl-terminated branched polyether, and the water-soluble inorganic zinc salt.

[0095] The polyquaternary ammonium salt scale inhibitor component is the same as in Example 1; the carboxyl-terminated branched polyether is the same as in Example 1, and the remaining raw materials and preparation process are the same as in Example 1.

[0096] Performance tests were performed on Examples 1-8 and Comparative Examples 1-4;

[0097] Water samples to be treated: The composition of the water samples in the following examples and comparative examples is shown in Table 1 below:

[0098] Table 1

[0099]

[0100] The performance test standard for the scale inhibitor CaCO3 of the environmentally friendly phosphorus-free corrosion and scale inhibitor is based on the standard GB / T 16632-2019 "Determination of Scale Inhibition Performance of Water Treatment Agents - Calcium Carbonate Deposition Method". The addition amount of the environmentally friendly phosphorus-free corrosion and scale inhibitor in each liter of water sample is 100 mg.

[0101] The corrosion inhibition performance of environmentally friendly phosphorus-free corrosion and scale inhibitors on low-carbon steel was tested according to standard GB / T18175-2014, including corrosion rate. v (mm / a) Calculation formula: In the formula t The soaking time (h) is the experimental soaking time. s The surface area of ​​the hanging piece (cm²) 2） ; r The density of the hanging sheets (g / cm³) 3） ; m 0 The average weight loss (g) of the acid washing blank group; m The difference in mass before and after the hanging test is (g); 10 is the conversion between the length units millimeter and centimeter (mm / cm); 8760 is the number of hours in a year (h / a).

[0102] Zinc salt stability: in Ca 2+ The concentration is 250 g / L, Zn 2+ The concentration is 5 mg / L, HCO3 - The zinc salt stability rate was recorded and calculated under the following conditions: a concentration of 250 mg / L (calculated as CaCO3), a solution pH of 9, an experimental temperature of 80℃, and a constant temperature for 10 hours. The scale inhibition dosage of the environmentally friendly, phosphorus-free corrosion and scale inhibitor was 50 mg / L. The calculation formula is: Zinc salt stability rate = (final zinc ion concentration - zinc ion concentration in the water sample without scale inhibitor) / (initial zinc ion concentration with scale inhibitor - zinc ion concentration in the water sample without scale inhibitor) × 100%.

[0103] The results are shown in Table 2:

[0104] Table 2

[0105]

[0106] As shown in Table 2, the environmentally friendly phosphorus-free corrosion and scale inhibitor prepared by this invention has good scale inhibition and slow-release effects. Furthermore, it maintains good zinc stabilization effects even in long-term high-temperature environments.

[0107] According to the comparison between Example 1 and Comparative Example 1, the introduction of quaternary ammonium salt groups in the polyquaternary ammonium salt scale inhibitor component helps to improve its dispersibility and electrostatic adsorption capacity. According to the comparison between Example 1 and Comparative Example 2, the introduction of carboxyl branched polyether improves the thermal stability and slow-release effect of the environmentally friendly phosphorus-free corrosion and scale inhibitor. According to Comparative Example 4, the amount of carboxyl branched polyether should not be too much. Excessive amount may lead to intermolecular entanglement or competitive adsorption with the polyquaternary ammonium salt scale inhibitor, which will reduce the overall corrosion and scale inhibition effect.

[0108] The comparison between Example 1 and Comparative Examples 1-3 shows that there is a significant synergistic effect between the polyquaternary ammonium salt scale inhibitor and the carboxyl-terminated branched polyether. The combination of the two can form a denser protective film, while simultaneously improving the scale inhibition ability and enhancing the high-temperature stability of the system.

[0109] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0110] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly non-phosphorus corrosion and scale inhibitor, characterized in that, The raw materials include: polyquaternary ammonium salt scale inhibitor, carboxyl-terminated branched polyether, and water-soluble inorganic zinc salt; The polyquaternary ammonium salt scale inhibitor is a copolymer of methacryloyloxyethyltrimethylammonium chloride, a vinyl monomer containing sulfonic acid groups, and an unsaturated carboxyl monomer. The terminal carboxyl branched polyether is obtained by ring-opening polymerization of quinolinyl methanol as the core and glycidol as the reactant monomer to obtain a terminal hydroxy branched polyether, which is then end-capped with succinic anhydride. The mass ratio of the polyquaternary ammonium salt scale inhibitor component, the carboxyl-terminated branched polyether, and the water-soluble inorganic zinc salt is 1:0.3-1:0.2-0.6; The polyquaternary ammonium salt scale inhibitor component is prepared by the following steps: Methacryloxyethyltrimethylammonium chloride, a vinyl monomer containing a sulfonic acid group, and sodium bisulfite were added to water. The temperature was set to 78-80℃. Ammonium persulfate was added, followed by an unsaturated carboxyl monomer. After the addition was complete, the temperature was kept constant, and the reaction was continued with stirring for 3-4 hours to obtain a polyquaternary ammonium salt scale inhibitor component. The molar ratio of methacryloxyethyltrimethylammonium chloride, the vinyl monomer containing a sulfonic acid group, and the unsaturated carboxyl monomer was 1-2:1-2:

4. The terminal carboxyl branched polyether is prepared by the following steps: Under nitrogen protection, quinolinyl methanol and potassium methoxide are added to dioxane, the temperature is raised to 90-95℃, and glycidol is added. After the addition is complete, the reaction is stirred for 4-5 hours to obtain hydroxyl-terminated branched polyether. The hydroxyl-terminated branched polyether is added to N,N-dimethylformamide, succinic anhydride and sulfuric acid are added, the temperature is set to 65-70℃, and the reaction is stirred for 3-4 hours to obtain carboxyl-terminated branched polyether. The amount of potassium methoxide added is 0.01% of the total mass of quinolinyl methanol and glycidol; the molar ratio of quinolinyl methanol to glycidol is 1:18-20; the ratio of hydroxyl-terminated branched polyether, succinic anhydride and sulfuric acid is 5-5.5g:0.08mol:0.07g.

2. The environment-friendly non-phosphorus corrosion and scale inhibitor according to claim 1, characterized in that, The vinyl monomer containing a sulfonic acid group is one of sodium styrene sulfonate and 2-acrylamide-2-methylpropanesulfonic acid.

3. The environment-friendly non-phosphorus corrosion and scale inhibitor according to claim 1, characterized in that, The unsaturated carboxyl monomer is at least one of itaconic acid, maleic acid, and acrylic acid.

4. The environment-friendly non-phosphorus corrosion and scale inhibitor according to claim 1, characterized in that, Water-soluble inorganic zinc salts are one of zinc chloride, zinc sulfate, and zinc nitrate.

5. The environment-friendly non-phosphorus corrosion and scale inhibitor according to claim 1, characterized in that, Quinolinylmethanol is one of 2-quinolinylmethanol, 6-quinolinylmethanol, and 8-quinolinylmethanol.

6. A method for preparing an environmentally friendly non-phosphorus corrosion and scale inhibitor, for preparing the environmentally friendly non-phosphorus corrosion and scale inhibitor according to any one of claims 1-5, characterized in that, The process includes the following steps: adding the raw materials to water and stirring to obtain an environmentally friendly, phosphorus-free corrosion and scale inhibitor.

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