Environment-friendly corrosion inhibitor and preparation method thereof

Abstract

The invention relates to the field of corrosion inhibitors, in particular to an environment-friendly corrosion inhibitor and a preparation method thereof, which are used for solving the problems that the corrosion inhibition effect of the existing corrosion inhibitor is limited, and the environment is possibly polluted and the human health is harmed in the use process. All the components in the environment-friendly corrosion inhibitor have good environment-friendly performance, the environment-friendly corrosion inhibitor is environmentally friendly, the development requirement of green chemistry is met, the metal surface can be effectively protected under the synergistic effect of the composite modified chitosan and the modified zinc oxide, and then corrosion media are effectively prevented from permeating the metal surface; the corrosion speed of metal is obviously reduced, the metal corrosion inhibitor is endowed with an excellent corrosion inhibition effect, and the metal corrosion inhibitor is suitable for protection of various metal materials in different corrosion environments and has good universality; meanwhile, the preparation method is simple in process, convenient to operate, low in cost and suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the field of corrosion inhibitors, and in particular to an environmentally friendly corrosion inhibitor and a preparation method thereof. Background Art

[0002] Metal materials are widely used in construction, marine engineering, transportation, oil production, and metal processing equipment. However, metal corrosion is also a common phenomenon. Metal corrosion not only leads to a decline in performance and shortened service life of metal materials, but also causes resource waste and environmental pollution. To prevent metal corrosion, people have adopted a variety of methods, among which the use of corrosion inhibitors is an economical, effective, and widely used method.

[0003] The corrosion inhibition effect of traditional corrosion inhibitors is limited, and they may pollute the environment and harm human health during use. With the increasing awareness of environmental protection and the demand for sustainable development, the development of an environmentally friendly corrosion inhibitor and its preparation method has important practical significance. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of the present invention is to provide an environmentally friendly corrosion inhibitor and a preparation method thereof, which solves the problem that the existing corrosion inhibitors have limited corrosion inhibition effects and may pollute the environment and cause harm to human health during use.

[0005] The purpose of the present invention can be achieved through the following technical solutions: An environmentally friendly corrosion inhibitor comprises the following components in parts by weight: 30-40 parts of composite modified chitosan, 5-13 parts of modified zinc oxide, 2-4 parts of polyethylene glycol, 1-5 parts of surfactant, 30-35 parts of anhydrous ethanol and 50-60 parts of deionized water; Wherein, the composite modified chitosan is a mixture of quaternized chitosan and fluorine-grafted chitosan in a mass ratio of 2:0.5-1.1; Wherein, the quaternized chitosan is prepared by the following steps: Chitosan, sodium hydroxide solution and 3-chloro-2-hydroxypropyltrimethylammonium chloride are added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen protection is introduced. The mixture is stirred and reacted for 5-10 minutes at a temperature of 25-30° C. and a stirring rate of 200-300 r / min. The mixture is then heated to 70-75° C. and stirred for 8-10 hours. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is then washed with distilled water and anhydrous ethanol for 3-5 times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 50-55° C. for 3-4 hours to obtain quaternized chitosan.

[0006] As a further solution of the present invention: the usage ratio of the chitosan, sodium hydroxide solution and 3-chloro-2-hydroxypropyltrimethylammonium chloride is 2g:40-45mL:1.2-3.6g.

[0007] As a further solution of the present invention: the chitosan is chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa; the mass fraction of the sodium hydroxide solution is 10-12%.

[0008] As a further solution of the present invention: the fluorine-grafted chitosan is prepared by the following steps: Step a1: perfluorobutyric acid and N,N-dimethylformamide are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred at a temperature of 25-30°C and a stirring rate of 200-300 r / min for 20-30 minutes, and then thionyl chloride is added dropwise while stirring at a rate of 1-2 drops / s. After the addition is complete, the temperature is raised to 80-85°C and the stirring reaction is continued for 2-3 hours. After the reaction is completed, the reaction product is cooled to room temperature and then distilled at atmospheric pressure. The fraction at 39°C is collected to obtain perfluorobutyryl chloride; Step a2: chitosan, N, N-dimethylformamide and glacial acetic acid are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection is introduced. The mixture is stirred and reacted for 20-30 minutes at a temperature of 25-30°C and a stirring rate of 200-300r / min. Then, perfluorobutyryl chloride is added dropwise while stirring, and the dropwise acceleration rate is controlled to 1-2 drops / s. After the addition is completed, the temperature is raised to 90-95°C and the stirring reaction is continued for 3-5 hours. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is then washed with distilled water and anhydrous ethanol for 3-5 times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 50-55°C for 3-4 hours to obtain fluorine-grafted chitosan.

[0009] As a further embodiment of the present invention: the usage ratio of the perfluorobutyric acid, N,N-dimethylformamide and thionyl chloride in step a1 is 50 mmol: 0.4-0.5 g: 100 mmol.

[0010] As a further embodiment of the present invention, the chitosan, N,N-dimethylformamide, glacial acetic acid and perfluorobutyryl chloride in step a2 are used in a ratio of 2 g: 20-25 mL: 20-25 mL: 6-10 mL; and the chitosan has a degree of deacetylation of 85% and a molecular weight of 10 kDa.

[0011] As a further solution of the present invention: the modified zinc oxide is prepared by the following steps: Anhydrous ethanol and deionized water are added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture is stirred and reacted for 3-5 minutes at a temperature of 25-30°C and a stirring rate of 200-300 r / min. The pH is then adjusted to 8-9 with an ammonia solution, and the mixture is stirred and reacted for 3-5 minutes. Bis[3-(triethoxysilyl)propyl]amine is then added and the stirring reaction is continued for 20-30 minutes. Nano-zinc oxide is then added and the stirring reaction is continued for 10-15 minutes. The mixture is heated to 80-85°C and the stirring reaction is continued for 5-6 hours. After the reaction is completed, the reaction product is cooled to room temperature and then centrifuged. The precipitate is then washed with distilled water for 3-5 times, and then placed in a vacuum drying oven and dried at a temperature of 60-65°C for 2-3 hours to obtain modified zinc oxide.

[0012] As a further solution of the present invention, the usage ratio of anhydrous ethanol, deionized water, bis[3-(triethoxysilyl)propyl]amine and nano zinc oxide is 60-70 mL: 20-30 mL: 0.8-3.6 g: 5 g.

[0013] As a further solution of the present invention: the mass fraction of the ammonia solution is 20-25%; the nano zinc oxide has an average diameter of 100 nm.

[0014] As a further solution of the present invention: a method for preparing an environmentally friendly corrosion inhibitor comprises the following steps: Step 1: Weigh 30-40 parts of composite modified chitosan, 5-13 parts of modified zinc oxide, 2-4 parts of polyethylene glycol, 1-5 parts of surfactant, 30-35 parts of anhydrous ethanol and 50-60 parts of deionized water according to weight parts and set aside; Step 2: Add the composite modified chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stir and mix for 0.5-2.5 hours at a temperature of 25-30° C. and a stirring rate of 600-800 r / min to obtain an environmentally friendly corrosion inhibitor.

[0015] As a further embodiment of the present invention: the polyethylene glycol is polyethylene glycol 400.

[0016] As a further embodiment of the present invention, the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80 and Span 80 in a mass ratio of 1:2:1.

[0017] Beneficial effects of the present invention: The present invention discloses an environment-friendly corrosion inhibitor and a preparation method thereof. The environment-friendly corrosion inhibitor is obtained by stirring and mixing composite modified chitosan, modified zinc oxide, polyethylene glycol, a surfactant, anhydrous ethanol and deionized water. Each component in the environment-friendly corrosion inhibitor has good environmental performance, is environmentally friendly, and meets the development requirements of green chemistry. Under the synergistic action of the composite modified chitosan and the modified zinc oxide, the metal surface can be effectively protected, thereby effectively preventing the penetration of corrosive media into the metal surface, significantly slowing down the corrosion rate of the metal, and imparting an excellent corrosion inhibition effect. The inhibitor is suitable for protecting a variety of metal materials in different corrosive environments and has good versatility. At the same time, the preparation method has a simple process, is easy to operate, has low cost, and is suitable for large-scale industrial production.

[0018] In the process of preparing the environmentally friendly corrosion inhibitor, a composite modified chitosan is first prepared. The composite modified chitosan is a compound of quaternized chitosan and fluorine-grafted chitosan. Chitosan and 3-chloro-2-hydroxypropyltrimethylammonium chloride are reacted, and chitosan and 3-chloro-2-hydroxypropyltrimethylammonium chloride are reacted. The amino group and the hydroxyl group on the chitosan react with the chlorine atom on the 3-chloro-2-hydroxypropyltrimethylammonium chloride, thereby grafting a quaternary ammonium group onto the chitosan to obtain quaternized chitosan. Perfluorobutyric acid is treated with thionyl chloride to convert the carboxyl group on the perfluorobutyric acid into an acyl chloride group to obtain perfluorobutyryl chloride. Then, chitosan and perfluorobutyryl chloride are reacted, and the amino group and hydroxyl group on the chitosan react with the acyl chloride group on the perfluorobutyryl chloride, thereby grafting a fluorine-containing group onto the chitosan to obtain a fluorine-grafted chitosan. Branched chitosan; chitosan has good biodegradability and is environmentally friendly. The chitosan structure contains a large number of amino and hydroxyl groups, which can form coordination bonds with metal atoms on the metal surface. After the introduction of quaternary ammonium groups, it can strongly adsorb to the negatively charged areas of the metal surface due to corrosion through electrostatic action, further enhancing the adsorption effect. After the introduction of fluorine-containing groups, its low surface energy and hydrophobicity are utilized to give it excellent waterproof and corrosion resistance. Therefore, under the synergistic effect of quaternized chitosan and fluorine-grafted chitosan, a continuous, dense and stable protective film can be formed on the metal surface, effectively preventing the contact between the corrosive medium and the metal surface, and can effectively prevent the adsorption and penetration of moisture and corrosive ions, thereby slowing down the corrosion rate of the metal and improving the corrosion resistance of the metal.

[0019] In the process of preparing the environmentally friendly corrosion inhibitor, a modified zinc oxide was first prepared. The modified zinc oxide was treated with bis[3-(triethoxysilyl)propyl]amine and nano-zinc oxide. The siloxane on the bis[3-(triethoxysilyl)propyl]amine was hydrolyzed to form silanol, which could be grafted onto the surface of nano-zinc oxide particles to obtain modified zinc oxide. Nano-zinc oxide is non-toxic and harmless. It will slowly release free positively charged zinc ions in aqueous solution, which can react with the product OH of the cathode reaction. -The reaction generates insoluble Zn(OH)2, which is deposited in the cathode area, making it difficult for oxygen to reach the cathode, thereby slowing down the cathode reaction and making it have a corrosion inhibition effect. In addition, the introduction of organic silicon to the surface of zinc oxide can improve its stability, and the introduced silanol groups can react chemically with the active groups in it to form chemical bonds, making the structure of the protective film tighter and the performance better. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention. Example 1

[0021] This embodiment is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 40 mL of a 10% mass fraction sodium hydroxide solution, and 1.2 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride were added to a three-necked flask equipped with a stirrer, a thermometer, and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at 25° C. and a stirring rate of 200 r / min for 5 minutes, and then the temperature was raised to 70° C. and the stirring reaction was continued for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was then washed three times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at 50° C. for 3 hours to obtain quaternized chitosan; Step S2: 50 mmol of perfluorobutyric acid and 0.4 g of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, and a constant pressure dropping funnel. The mixture was protected by nitrogen and stirred at 25°C and a stirring rate of 200 r / min for 20 minutes. Then, 100 mmol of thionyl chloride was added dropwise while stirring at a rate of 1 drop / s. After the addition was completed, the temperature was raised to 80°C and the stirring reaction was continued for 2 hours. After the reaction was completed, the reaction product was cooled to room temperature and then distilled at atmospheric pressure. The fraction at 39°C was collected to obtain perfluorobutyryl chloride; Step S3: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 20 mL of N,N-dimethylformamide and 20 mL of glacial acetic acid were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred and reacted for 20 minutes at a temperature of 25° C. and a stirring rate of 200 r / min. Then, 6 mL of perfluorobutyryl chloride was added dropwise while stirring, and the dropping rate was controlled to 1 drop / s. After the addition was completed, the temperature was raised to 90° C. and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed three times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at a temperature of 50° C. for 3 hours to obtain fluorine-grafted chitosan; Step S4: 60 mL of anhydrous ethanol and 20 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at a temperature of 25° C. and a stirring rate of 200 r / min for 3 minutes. The pH was then adjusted to 8 with a 20% ammonia aqueous solution, and the mixture was stirred for 3 minutes. 0.8 g of bis[3-(triethoxysilyl)propyl]amine was then added and the mixture was stirred for 20 minutes. 5 g of nano-zinc oxide with an average diameter of 100 nm was then added and the mixture was stirred for 10 minutes. The mixture was heated to 80° C. and stirred for 5 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water three times in sequence, and then placed in a vacuum drying oven and dried at 60° C. for 2 hours to obtain modified zinc oxide. Step S5: Weigh 30 parts of composite modified chitosan, 5 parts of modified zinc oxide, 2 parts of polyethylene glycol, 1 part of surfactant, 30 parts of anhydrous ethanol and 50 parts of deionized water according to weight parts and set aside; the composite modified chitosan is a mixture of quaternized chitosan and fluorine-grafted chitosan in a mass ratio of 2:0.5; the polyethylene glycol is polyethylene glycol 400; and the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80 and Span 80 in a mass ratio of 1:2:1; Step S6: adding the composite modified chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing them at a temperature of 25° C. and a stirring rate of 600 r / min for 0.5 h to obtain an environmentally friendly corrosion inhibitor. Example 2

[0022] This embodiment is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 42 mL of a sodium hydroxide solution with a mass fraction of 11%, and 2.4 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride were added to a three-necked flask equipped with a stirrer, a thermometer, and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 28° C. and a stirring rate of 250 r / min for 8 minutes, and then the temperature was raised to 72° C. and the stirring reaction was continued for 9 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was then washed four times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at a temperature of 52° C. for 3.5 hours to obtain quaternized chitosan; Step S2: 50 mmol of perfluorobutyric acid and 0.45 g of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube, and a constant pressure dropping funnel. The mixture was protected by nitrogen and stirred at 28° C. and a stirring rate of 250 r / min for 25 minutes. Then, 100 mmol of thionyl chloride was added dropwise while stirring at a rate of 1 drop / s. After the addition was completed, the temperature was raised to 82° C. and the stirring reaction was continued for 2.5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then distilled at atmospheric pressure. The fraction at 39° C. was collected to obtain perfluorobutyryl chloride; Step S3: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 22 mL of N,N-dimethylformamide and 22 mL of glacial acetic acid were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred and reacted for 25 minutes at a temperature of 28° C. and a stirring rate of 250 r / min. Then, 8 mL of perfluorobutyryl chloride was added dropwise while stirring, and the dropping rate was controlled to 1 drop / s. After the addition was completed, the mixture was heated to 92° C. and the stirring reaction was continued for 4 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed four times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at a temperature of 52° C. for 3.5 hours to obtain fluorine-grafted chitosan; Step S4: 65 mL of anhydrous ethanol and 25 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at a temperature of 28° C. and a stirring rate of 250 r / min for 4 minutes. The pH was then adjusted to 8.5 with a 22% ammonia aqueous solution, and the mixture was stirred for 4 minutes. 2.2 g of bis[3-(triethoxysilyl)propyl]amine was then added and the mixture was stirred for 25 minutes. 5 g of nano-zinc oxide with an average diameter of 100 nm was then added and the mixture was stirred for 12 minutes. The mixture was heated to 82° C. and stirred for 5.5 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water four times in sequence, and then placed in a vacuum drying oven and dried at 62° C. for 2.5 hours to obtain modified zinc oxide. Step S5: Weigh 35 parts of composite modified chitosan, 9 parts of modified zinc oxide, 3 parts of polyethylene glycol, 3 parts of surfactant, 32 parts of anhydrous ethanol and 55 parts of deionized water in parts by weight and set aside; the composite modified chitosan is a mixture of quaternized chitosan and fluorine-grafted chitosan in a mass ratio of 2:0.8; the polyethylene glycol is polyethylene glycol 400; and the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80 and Span 80 in a mass ratio of 1:2:1; Step S6: adding the composite modified chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing at a temperature of 28° C. and a stirring rate of 700 r / min for 1.5 h to obtain an environmentally friendly corrosion inhibitor. Example 3

[0023] This embodiment is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 45 mL of a sodium hydroxide solution with a mass fraction of 12%, and 3.6 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride were added to a three-necked flask equipped with a stirrer, a thermometer, and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 10 minutes, and then the temperature was raised to 75° C. and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was then washed with distilled water and anhydrous ethanol five times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain quaternized chitosan; Step S2: 50 mmol of perfluorobutyric acid and 0.5 g of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 30 minutes. Then, 100 mmol of thionyl chloride was added dropwise while stirring at a rate of 2 drops / s. After the addition was completed, the temperature was raised to 85° C. and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then distilled at atmospheric pressure. The fraction at a temperature of 39° C. was collected to obtain perfluorobutyryl chloride; Step S3: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 25 mL of N,N-dimethylformamide and 25 mL of glacial acetic acid were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred and reacted for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min. Then, 10 mL of perfluorobutyryl chloride was added dropwise while stirring, and the dropping rate was controlled to 2 drops / s. After the addition was completed, the temperature was raised to 95° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed 5 times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain fluorine-grafted chitosan; Step S4: 70 mL of anhydrous ethanol and 30 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 5 minutes. The pH was then adjusted to 9 with a 25% ammonia aqueous solution, and the mixture was stirred for 5 minutes. 3.6 g of bis[3-(triethoxysilyl)propyl]amine was then added and the mixture was stirred for 30 minutes. 5 g of nano-zinc oxide with an average diameter of 100 nm was then added and the mixture was stirred for 15 minutes. The mixture was heated to 85° C. and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times in sequence, and then placed in a vacuum drying oven and dried at 65° C. for 3 hours to obtain modified zinc oxide. Step S5: Weigh 40 parts of composite modified chitosan, 13 parts of modified zinc oxide, 4 parts of polyethylene glycol, 5 parts of surfactant, 35 parts of anhydrous ethanol and 60 parts of deionized water in parts by weight for later use; the composite modified chitosan is a mixture of quaternized chitosan and fluorine-grafted chitosan in a mass ratio of 2:1.1; the polyethylene glycol is polyethylene glycol 400; and the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80 and Span 80 in a mass ratio of 1:2:1; Step S6: adding the composite modified chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 h to obtain an environmentally friendly corrosion inhibitor.

[0024] Comparative Example 1: This comparative example is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: Weigh 4 parts of polyethylene glycol, 5 parts of a surfactant, 35 parts of anhydrous ethanol, and 60 parts of deionized water according to weight and set aside; the polyethylene glycol is polyethylene glycol 400; the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80, and Span 80 in a mass ratio of 1:2:1; Step S2: adding polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 hours to obtain an environmentally friendly corrosion inhibitor.

[0025] Comparative Example 2: This comparative example is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: Weigh 40 parts of chitosan with a degree of deacetylation of 85% and a molecular weight of 10 kDa, 13 parts of nano-zinc oxide with an average diameter of 100 nm, 4 parts of polyethylene glycol, 5 parts of a surfactant, 35 parts of anhydrous ethanol, and 60 parts of deionized water according to weight, and set aside; the polyethylene glycol is polyethylene glycol 400; the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80, and Span 80 in a mass ratio of 1:2:1; Step S2: chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, nano zinc oxide with an average diameter of 100 nm, polyethylene glycol, a surfactant, anhydrous ethanol and deionized water are added to a mixer, and stirred and mixed at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 hours to obtain an environmentally friendly corrosion inhibitor.

[0026] Comparative Example 3: This comparative example is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 70 mL of anhydrous ethanol and 30 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 5 minutes. Then, the pH was adjusted to 9 with a 25% ammonia aqueous solution, and the stirring reaction was continued for 5 minutes. Then, 3.6 g of bis[3-(triethoxysilyl)propyl]amine was added and the stirring reaction was continued for 30 minutes. Then, 5 g of nano-zinc oxide with an average diameter of 100 nm was added and the stirring reaction was continued for 15 minutes. Then, the temperature was raised to 85° C. and the stirring reaction was continued for 6 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. Then, the precipitate was washed with distilled water 5 times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 65° C. for 3 hours to obtain modified zinc oxide; Step S2: Weigh 40 parts of chitosan with a degree of deacetylation of 85% and a molecular weight of 10 kDa, 13 parts of modified zinc oxide, 4 parts of polyethylene glycol, 5 parts of a surfactant, 35 parts of anhydrous ethanol, and 60 parts of deionized water according to weight and set aside; the polyethylene glycol is polyethylene glycol 400; the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80, and Span 80 in a mass ratio of 1:2:1; Step S3: chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, modified zinc oxide, polyethylene glycol, a surfactant, anhydrous ethanol and deionized water are added to a mixer, and stirred and mixed at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 hours to obtain an environmentally friendly corrosion inhibitor.

[0027] Comparative Example 4: This comparative example is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 45 mL of a sodium hydroxide solution with a mass fraction of 12%, and 3.6 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride were added to a three-necked flask equipped with a stirrer, a thermometer, and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 10 minutes, and then the temperature was raised to 75° C. and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was then washed with distilled water and anhydrous ethanol five times in sequence, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain quaternized chitosan; Step S2: 70 mL of anhydrous ethanol and 30 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 5 minutes. The pH was then adjusted to 9 with a 25% ammonia aqueous solution, and the mixture was stirred for 5 minutes. 3.6 g of bis[3-(triethoxysilyl)propyl]amine was then added and the mixture was stirred for 30 minutes. 5 g of nano-zinc oxide with an average diameter of 100 nm was then added and the mixture was stirred for 15 minutes. The mixture was heated to 85° C. and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times in sequence, and then placed in a vacuum drying oven and dried at 65° C. for 3 hours to obtain modified zinc oxide. Step S3: Weigh 40 parts of quaternized chitosan, 13 parts of modified zinc oxide, 4 parts of polyethylene glycol, 5 parts of a surfactant, 35 parts of anhydrous ethanol, and 60 parts of deionized water according to weight, and set aside; the polyethylene glycol is polyethylene glycol 400; the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80, and Span 80 in a mass ratio of 1:2:1; Step S4: adding quaternized chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 h to obtain an environmentally friendly corrosion inhibitor.

[0028] Comparative Example 5: This comparative example is a method for preparing an environmentally friendly corrosion inhibitor, comprising the following steps: Step S1: 50 mmol of perfluorobutyric acid and 0.5 g of N,N-dimethylformamide were added to a three-necked flask equipped with a stirrer, a thermometer, a gas guide tube, and a constant pressure dropping funnel. Nitrogen protection was introduced, and the mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 30 minutes. Then, 100 mmol of thionyl chloride was added dropwise while stirring at a rate of 2 drops / s. After the addition was completed, the temperature was raised to 85° C. and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then distilled at atmospheric pressure. The fraction at a temperature of 39° C. was collected to obtain perfluorobutyryl chloride; Step S2: 2 g of chitosan with a deacetylation degree of 85% and a molecular weight of 10 kDa, 25 mL of N,N-dimethylformamide and 25 mL of glacial acetic acid were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen protection was introduced. The mixture was stirred and reacted for 30 minutes at a temperature of 30° C. and a stirring rate of 300 r / min. Then, 10 mL of perfluorobutyryl chloride was added dropwise while stirring, and the dropping rate was controlled to 2 drops / s. After the addition was completed, the temperature was raised to 95° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed 5 times with distilled water and anhydrous ethanol in sequence, and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain fluorine-grafted chitosan; Step S3: 70 mL of anhydrous ethanol and 30 mL of deionized water were added to a three-necked flask equipped with a stirrer and a thermometer, and the mixture was stirred at a temperature of 30° C. and a stirring rate of 300 r / min for 5 minutes. The pH was then adjusted to 9 with a 25% ammonia aqueous solution, and the mixture was stirred for 5 minutes. 3.6 g of bis[3-(triethoxysilyl)propyl]amine was then added and the mixture was stirred for 30 minutes. 5 g of nano-zinc oxide with an average diameter of 100 nm was then added and the mixture was stirred for 15 minutes. The mixture was heated to 85° C. and stirred for 6 hours. After the reaction, the reaction product was cooled to room temperature and then centrifuged. The precipitate was washed with distilled water 5 times in sequence, and then placed in a vacuum drying oven and dried at 65° C. for 3 hours to obtain modified zinc oxide. Step S4: Weigh 40 parts of fluorine-grafted chitosan, 13 parts of modified zinc oxide, 4 parts of polyethylene glycol, 5 parts of a surfactant, 35 parts of anhydrous ethanol, and 60 parts of deionized water according to weight, and set aside; the polyethylene glycol is polyethylene glycol 400; the surfactant is a mixture of sodium lauryl sulfate, polysorbate 80, and Span 80 in a mass ratio of 1:2:1; Step S5: adding fluorine-grafted chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stirring and mixing at a temperature of 30° C. and a stirring rate of 800 r / min for 2.5 h to obtain an environmentally friendly corrosion inhibitor.

[0029] Performance test: A Q235 carbon steel sample with a size of 50 mm × 25 mm × 2 mm was polished to 2000 mesh with water abrasive paper, then washed with distilled water and anhydrous ethanol, drained, and then immersed in a corrosion liquid with an addition amount of 0.5% of the environmentally friendly corrosion inhibitor from Examples 1-3 and Comparative Examples 1-5 for 12 hours. Then, it was washed with distilled water and anhydrous ethanol again, drained, and then placed in a vacuum drying oven and dried at a temperature of 60°C for 3 hours. After that, it was weighed, and the corrosion inhibition rate was calculated according to the static weight loss method; wherein, the corrosion liquid is a hydrochloric acid solution with a molar concentration of 0.5 mol / L and a sodium chloride solution with a mass fraction of 5%.

[0030] The test results are shown in the following table:

[0031] Referring to the data in the above table, based on the comparison between Examples 1-3 and Comparative Examples 1-5, it can be seen that the addition of composite modified chitosan and modified zinc oxide can significantly improve the corrosion inhibition effect of the environmentally friendly corrosion inhibitor, and under the synergistic effect of the two, the prepared environmentally friendly corrosion inhibitor has excellent corrosion inhibition performance.

[0032] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0033] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the scope of protection of the present invention.

Claims

1. An environmentally friendly corrosion inhibitor, characterized in that: It comprises the following components in parts by weight: 30-40 parts of composite modified chitosan, 5-13 parts of modified zinc oxide, 2-4 parts of polyethylene glycol, 1-5 parts of surfactant, 30-35 parts of anhydrous ethanol and 50-60 parts of deionized water; Wherein, the composite modified chitosan is a mixture of quaternized chitosan and fluorine-grafted chitosan in a mass ratio of 2:0.5-1.1; Wherein, the quaternized chitosan is prepared by the following steps: Chitosan, sodium hydroxide solution and 3-chloro-2-hydroxypropyltrimethylammonium chloride are stirred for reaction. After the reaction is completed, the reaction product is cooled and then centrifuged. The precipitate is washed and dried to obtain quaternized chitosan.

2. An environmentally friendly corrosion inhibitor according to claim 1, characterized in that, The chitosan, sodium hydroxide solution and 3-chloro-2-hydroxypropyltrimethylammonium chloride are used in a ratio of 2 g:40-45 mL:1.2-3.6 g; the chitosan has a deacetylation degree of 85% and a molecular weight of 10 kDa; and the mass fraction of the sodium hydroxide solution is 10-12%.

3. An environmentally friendly corrosion inhibitor according to claim 1, characterized in that, The fluorine-grafted chitosan is prepared by the following steps: Step a1: stirring perfluorobutyric acid and N,N-dimethylformamide for reaction, then adding thionyl chloride and continuing the stirring reaction. After the reaction is completed, the reaction product is cooled and then distilled under normal pressure to collect the fractions to obtain perfluorobutyryl chloride; Step a2: Chitosan, N,N-dimethylformamide and glacial acetic acid are stirred for reaction, and then perfluorobutyryl chloride is added and the stirring reaction is continued. After the reaction is completed, the reaction product is cooled and then centrifuged. The precipitate is then washed and dried to obtain fluorine-grafted chitosan.

4. An environmentally friendly corrosion inhibitor according to claim 3, characterized in that, The usage ratio of the perfluorobutyric acid, N,N-dimethylformamide and thionyl chloride in step a1 is 50 mmol: 0.4-0.5 g: 100 mmol.

5. An environmentally friendly corrosion inhibitor according to claim 3, characterized in that, The chitosan, N,N-dimethylformamide, glacial acetic acid and perfluorobutyryl chloride in step a2 are used in a ratio of 2 g: 20-25 mL: 20-25 mL: 6-10 mL; the chitosan has a deacetylation degree of 85% and a molecular weight of 10 kDa.

6. An environmentally friendly corrosion inhibitor according to claim 1, characterized in that, The modified zinc oxide is prepared by the following steps: Anhydrous ethanol and deionized water are stirred to react, and then the pH is adjusted with an ammonia solution. Then, bis[3-(triethoxysilyl)propyl]amine and nano zinc oxide are added and the stirring reaction is continued. After the reaction is completed, the reaction product is cooled and then centrifuged. The precipitate is then washed and dried to obtain modified zinc oxide.

7. An environmentally friendly corrosion inhibitor according to claim 6, characterized in that: The usage ratio of anhydrous ethanol, deionized water, bis[3-(triethoxysilyl)propyl]amine and nano zinc oxide is 60-70 mL: 20-30 mL: 0.8-3.6 g: 5 g; the mass fraction of the ammonia solution is 20-25%; and the nano zinc oxide has an average diameter of 100 nm.

8. A method for preparing an environmentally friendly corrosion inhibitor, characterized in that: The following steps are involved: Step 1: Weigh 30-40 parts of composite modified chitosan, 5-13 parts of modified zinc oxide, 2-4 parts of polyethylene glycol, 1-5 parts of surfactant, 30-35 parts of anhydrous ethanol and 50-60 parts of deionized water according to weight parts and set aside; Step 2: Add the composite modified chitosan, modified zinc oxide, polyethylene glycol, surfactant, anhydrous ethanol and deionized water into a mixer, stir and mix for 0.5-2.5 hours at a temperature of 25-30° C. and a stirring rate of 600-800 r / min to obtain an environmentally friendly corrosion inhibitor.

9. The method for preparing an environmentally friendly corrosion inhibitor according to claim 8, characterized in that: The polyethylene glycol is polyethylene glycol 400.

10. The method for preparing an environmentally friendly corrosion inhibitor according to claim 8, characterized in that: The surfactant is a mixture of sodium lauryl sulfate, polysorbate 80 and Span 80 in a mass ratio of 1:2:1.

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