An oil-based corrosion inhibitor composition and a method of making the same

Abstract

The application discloses an oil-based corrosion inhibitor composition and a preparation method thereof, and belongs to the technical field of metal corrosion protection. The composition takes mineral base oil as a main component, adds amino polypyrrine covalent bridging bismuth selenide composite nanomaterial and conventional auxiliary additives. The composite nanomaterial is formed by the fact that the side chain of the amino polypyrrine has a primary amino group, after being grafted by double functional groups, a covalent bonding structure is formed with the edge hydroxylated bismuth selenide nanosheet through esterification bridging. The material is stably dispersed in the oil-based system, and can effectively exert the synergistic corrosion inhibition effect of the organic corrosion inhibition group and the inorganic nanocarrier. In the preparation, the base oil and the auxiliary agent are mixed and dissolved, the nanomaterial is added after cooling and high-speed dispersion, and filtration is performed to obtain the composition. The composition has high corrosion inhibition efficiency, is suitable for long-term corrosion protection of various metal materials, and has simple preparation process.

Description

Technical Field

[0001] This invention belongs to the field of metal corrosion protection technology, specifically relating to an oil-based corrosion inhibitor composition and its preparation method. Background Technology

[0002] Oil-based corrosion inhibitors are important products in the field of metal corrosion protection, widely used in machining, equipment storage, and oil and gas extraction. Currently, common oil-based corrosion inhibitors are mainly prepared by dissolving organic corrosion inhibitors (such as sulfonates, amines, and esters) in mineral base oils, relying on the adsorption of inhibitor molecules on the metal surface to form a film that blocks corrosive media. In recent years, with the development of nanotechnology, researchers have attempted to introduce nanomaterials into corrosion inhibitor systems, utilizing the high specific surface area and strong adsorption properties of nanoparticles to improve corrosion inhibition performance. For example, there are reports of preparing composite corrosion inhibitors by covalently grafting ionic liquids onto graphene oxide nanosheets, or using polyaniline combined with carbon nanotubes for anti-corrosion greases. Furthermore, conductive polymers (such as polypyrrole and polyaniline) are also considered to have application potential in the field of corrosion inhibition due to their good corrosion resistance and environmental friendliness.

[0003] However, existing oil-based corrosion inhibitors still have many shortcomings. First, the dispersion system formed by conventional oil-soluble corrosion inhibitors in base oils is close to a colloidal solution, which is an unstable system. It is prone to precipitation after temperature changes or vigorous agitation. Although nanomaterials can improve some properties, their aggregation problem in oily media is particularly prominent, making it difficult to achieve long-term stable dispersion. Second, traditional corrosion inhibitors are mostly small-molecule organic compounds with single corrosion inhibition functions and lack multiple synergistic mechanisms, resulting in limited long-term protection capabilities in complex corrosive environments. Third, directly physically blending nanoparticles with organic corrosion inhibitors results in a lack of strong chemical bonds between the two, leading to poor interfacial compatibility. This not only affects the density of the corrosion film but also easily causes the corrosion-inhibiting components to gradually be lost during service. Summary of the Invention

[0004] The present invention aims to solve the technical problems of poor dispersion stability of nano-corrosion inhibitor components and insufficient interfacial compatibility with organic matrix in existing oil-based corrosion inhibitors, resulting in low corrosion inhibition efficiency and lack of long-term protection.

[0005] To achieve the above objectives, the present invention provides an oil-based corrosion inhibitor composition comprising the following raw materials in parts by weight: 150SN mineral oil base oil: 65-73 parts; amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials: 1-3 parts; dispersant stabilizer: 1.8-2.8 parts; antioxidant: 0.3-0.5 parts; cosolvent: 2.5-4 parts; The preparation method of the oily corrosion inhibitor composition includes the following steps: S1: Mix the 150SN mineral oil base oil, dispersant stabilizer, antioxidant and cosolvent according to the formula, heat to 50-60℃, and stir at 200-400r / min for 20-40min until completely dissolved; S2: Cool the dissolved solution to 25-35℃, add amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials, and disperse at a high speed of 3000-5000r / min for 30min; S3: After cooling the material obtained in S2 to room temperature, filter it through a 200-mesh filter, collect the filtrate, and let it stand for 12-24 hours to obtain the finished corrosion inhibitor.

[0006] Preferably, the dispersant stabilizer is polyisobutylene succinimide; the antioxidant is 2,6-di-tert-butyl-p-cresol; and the co-solvent is ethylene glycol monobutyl ether acetate.

[0007] Preferably, the kinematic viscosity of the 150SN mineral oil base oil at 40°C is 28-32 mmHg. 2 / s, flash point not lower than 200℃.

[0008] More preferably, the 150SN mineral oil base oil is selected from 150SN base oil produced by China Petroleum & Chemical Corporation Maoming Branch.

[0009] More preferably, the polyisobutylene succinimide dispersant and stabilizer is T154 ashless dispersant produced by Jinzhou Petrochemical Branch of China National Petroleum Corporation; the antioxidant is JADEWIN AN264(BHT) type 2,6-di-tert-butyl-p-cresol produced by Qingdao Jiedejia New Material Technology Co., Ltd.; and the cosolvent is BGA type ethylene glycol monobutyl ether acetate produced by Dow Chemical Company.

[0010] Preferably, in step S2, after high-speed dispersion, the slurry fineness is sampled and tested to be ≤5μm before entering the filtration process.

[0011] Preferably, the preparation method of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial includes the following steps: (1) Preparation of Bi2Se3 nanosheets: BiCl3 was dissolved in diethylene glycol, and the pH was adjusted to 8-9 with ammonia water. Na2SO3 and Se powder were added in sequence and stirred to obtain a suspension. The suspension was transferred to a polytetrafluoroethylene reactor, and diethylene glycol was added to 80% of the reactor volume. The temperature was raised to 150-180℃ and the reaction was carried out for 20-24 h. After cooling, the reactor was centrifuged at 6000-10000 r / min, washed with distilled water and anhydrous ethanol alternately 3-6 times, and vacuum dried for 8-12 h to obtain Bi2Se3 nanosheets. (2) Edge-selective hydroxylation activation: Bi2Se3 nanosheets were dispersed in H2O2 aqueous solution, deionized water was added, and the mixture was stirred for 30-60 min; centrifuged and vacuum dried for 6-10 h to obtain edge-selective hydroxylated Bi2Se3 nanosheets; (3) Synthesis of amino-polypyrrole: Under nitrogen protection, pyrrole and (1H-pyrrole-3-yl)methylamine were dissolved in anhydrous ethanol, and the mixture was cooled to 0-5℃ in an ice-water bath. An ethanol solution containing ferric chloride hexahydrate was added dropwise at a rate of 0.5-2 drops / second, and the mixture was stirred for 5-8 hours. After centrifugation, the filtrate was washed with deionized water until no yellow Fe was visible. 3+ The filtrate showed no white precipitate when tested with silver nitrate solution. After washing with ethanol 2-5 times and drying, aminopolypyrrole powder was obtained. The chemical reaction is illustrated below:

[0012] (4) Bifunctionalization grafting of aminopolypyrrole: The obtained aminopolypyrrole powder was dispersed in anhydrous dichloromethane; the temperature was lowered to 0-5℃, 2-chloromethylbenzimidazole, 3-chloropropionic acid and triethylamine were added, the temperature was raised to 50-60℃, and the reaction was stirred in the dark for 2-4 hours; the mixture was washed 2-5 times with sodium bicarbonate aqueous solution, 2-5 times with deionized water, and 1-3 times with anhydrous ethanol, and then dried under vacuum to obtain an aminopolypyrrole precursor with both benzimidazole and carboxyl end groups grafted onto its side chains; the chemical reaction is shown below:

[0013] (5) Esterification bridging: The edge-hydroxylated Bi2Se3 obtained in (2) was dispersed in a mixed solvent of anhydrous toluene and anhydrous dichloromethane in a volume ratio of 2:1-4:1 and sonicated; carboxylated amino polypyrrole precursor was added, followed by N,N'-dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP), and the mixture was sealed and stirred at room temperature for 12-24 h; the mixture was washed 1-3 times by centrifugation with a mixed solvent of n-hexane and anhydrous ethanol in a volume ratio of 1:1-1:5, and then dried under vacuum to obtain amino polypyrrole covalently bridged bismuth selenide composite nanomaterials; the chemical reaction is illustrated below:

[0014] In this invention, the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial not only serves as a corrosion inhibitor in oily corrosion inhibitors, but also as a functional unit for corrosion self-sensing and adaptive regulation. Its mechanism of action is as follows: When localized corrosion occurs on the metal surface coated with this corrosion inhibitor, a micro-electric field is generated in the corrosion micro-region due to the spatial separation of anodic dissolution and cathodic reduction reaction; the bismuth selenide, as a three-dimensional topological insulator material, has surface states that are highly sensitive to changes in electric field. The micro-electric field generated by corrosion causes a redistribution of the electronic state density on the bismuth selenide surface. This change in electronic state is transmitted to the amino-polypyrrole molecules bonded to it through the covalent bridging structure, thereby regulating the electron cloud density and frontier molecular orbital energy levels of the benzimidazole group and primary amino group on the side chain of amino-polypyrrole, significantly enhancing its coordination adsorption capacity with the metal surface; the enhanced chemisorption promotes the rapid formation of a dense protective film by the corrosion inhibitor molecules in the corrosion micro-region, blocking the contact between the corrosive medium and the metal substrate. After the corrosion reaction is inhibited, the local electric field disappears, the electronic state of bismuth selenide returns to its initial state, and the regulatory effect on the adsorption capacity of amino-polypyrrole stops accordingly. Thus, this invention realizes a closed-loop self-feedback mechanism for the corrosion inhibitor to sense, respond to, regulate and recover the corrosion micro-zone, endowing the corrosion inhibitor with intelligent adaptive anti-corrosion capabilities, and is suitable for sealing metal workpieces or protecting the inner wall of pipelines with an ambient temperature not exceeding 80℃ and a water content of less than 0.1%.

[0015] Preferably, the mass ratio of diethylene glycol to BiCl3 in (1) is 18-28:1.

[0016] Preferably, the molar ratio of BiCl3, Na2SO3 and Se powder in (1) is 1:1.5-3:1.5.

[0017] Preferably, the concentration of the H2O2 aqueous solution in (2) is 1 wt%-10 wt%.

[0018] Preferably, the molar ratio of pyrrole, (1H-pyrrole-3-yl)methylamine and ferric chloride hexahydrate in (3) is 1.8-2.0:1:2.2-2.8.

[0019] Preferably, the molar ratio of the total amount of 2-chloromethylbenzimidazole, 3-chloropropionic acid and aminopolypyrrole in (4) is 0.3-0.35:0.6-0.8:1.

[0020] Preferably, the molar ratio of 2-chloromethylbenzimidazole, 3-chloropropionic acid and triethylamine in (4) is 0.20-0.28:0.46-0.56:1.

[0021] Preferably, the concentration of the sodium bicarbonate aqueous solution in (4) is 2 wt%.

[0022] Preferably, the molar ratio of DMAP to DCC in (5) is 0.1-0.2:1.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention chemically grafts amino-polypyrrole onto the surface of two-dimensional bismuth selenide nanosheets via covalent bonds, forming a stable organic-inorganic composite structure. This fundamentally overcomes the inherent defects of traditional physical blending methods, where nanomaterials, due to their high surface energy, easily aggregate and subsequently precipitate from oily media. The covalently bridged structure allows the organic corrosion inhibitor to firmly adhere to the inorganic carrier surface. Combined with the synergistic effect of the polyisobutylene succinimide dispersant stabilizer, long-term uniform dispersion of the nanocomposite particles in base oil is achieved, effectively avoiding precipitation failure caused by temperature fluctuations or agitation during storage and use. Simultaneously, after edge-selective hydroxylation activation, the bismuth selenide nanosheets provide grafting reaction sites at the edges without disrupting their bulk layered structure. This preserves the physical barrier function of the nanosheets while providing a sufficient bonding basis for subsequent esterification bridging.

[0024] 2. In this invention, the amino-polypyrrole side chains are simultaneously grafted with benzimidazole groups and carboxyl end groups. The benzimidazole groups contain electron-rich nitrogen heterocyclic structures, which can form a stable coordination adsorption film on the metal surface. The carboxyl end groups, acting as bridging groups, form strong covalent bonds with the hydroxyl groups on the surface of bismuth selenide nanosheets through esterification. The primary amino groups provide additional adsorption sites. The synergistic chemisorption of multiple active sites enables the corrosion inhibitor to form a dense and uniform protective film on the metal surface, effectively blocking the contact between the corrosive medium and the metal substrate. At the same time, the large specific surface area of ​​the two-dimensional bismuth selenide nanosheets can extend the diffusion path of the corrosive medium and exert a physical shielding effect. The polypyrrole conductive polymer induces the formation of a passivation layer on the metal surface and inhibits anodic dissolution through redox activity. The covalent combination of the two integrates physical shielding, chemisorption, and interfacial passivation, making the corrosion inhibition efficiency of the composition of this invention significantly better than that of single-component or simple physical mixture corrosion inhibition systems under various corrosive environments such as neutral salt spray, acid, and humid heat.

[0025] 3. This invention is the first to introduce the electric field-sensitive characteristics of the topological insulator bismuth selenide into the field of corrosion inhibitors. Utilizing the electric field generated by the corrosion micro-region itself as a trigger signal, it achieves spontaneous sensing and in-situ response of the corrosion inhibitor to corrosion, without the need for external energy input or artificial intervention, thus overcoming the limitations of passive film formation in traditional corrosion inhibitors. As a three-dimensional topological insulator material, bismuth selenide's topologically protected surface states are highly sensitive to changes in electric field. When localized corrosion occurs on a metal surface coated with the corrosion inhibitor of this invention, a micro-electric field is generated in the corrosion micro-region due to the spatial separation of anodic dissolution and cathodic reduction reactions. This electric field causes a redistribution of the electronic state density on the bismuth selenide surface. This change in electronic state is transmitted to the bound amino-polypyrrole molecules through a covalent bridging structure, thereby regulating the electron cloud density and frontier molecular orbital energy levels of the benzimidazole groups and primary amines on the amino-polypyrrole side chains, significantly enhancing their coordination and adsorption capacity with the metal surface. This invention directly couples the electronic state changes of bismuth selenide with the adsorption capacity of aminopolypyrrole through a covalent bridging structure, forming a complete signal transmission chain: corrosion electric field → electronic state response of topological insulator → energy level regulation of corrosion inhibitor → adsorption enhancement → corrosion inhibition. This achieves a self-feedback closed-loop control throughout the entire process from corrosion initiation to regulation cessation. Furthermore, the response of bismuth selenide to the corrosion electric field and the regulation of its adsorption capacity to aminopolypyrrole in this invention are reversible—the electric field disappears after corrosion is inhibited, and the regulation effect automatically stops, avoiding ineffective consumption of the corrosion inhibitor in non-corrosion areas and enabling on-demand utilization of the corrosion inhibitor component. This intelligent self-feedback mechanism provides a completely new technical path for the field of corrosion inhibitors, representing a leap forward from passive protection to active intelligent protection.

[0026] 4. The preparation process of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials in this invention is carried out in an aqueous phase or conventional organic solvent at a moderate reaction temperature, without the need for high-temperature, high-pressure, or complex and expensive equipment. The preparation of the oily corrosion inhibitor composition also only requires conventional operations such as heating, stirring, high-speed dispersion, and filtration, making the process simple and controllable. All raw materials used are commercially available industrial-grade products, widely available and cost-controllable, suitable for large-scale industrial production and application. In addition, the composition of this invention can be applied to the sealing and rust prevention of various metal materials such as carbon steel, stainless steel, copper alloys, and aluminum alloys, as well as temporary protection during processing. It has no selective limitations on metal materials, has good universality, and can meet the corrosion prevention needs of different industrial fields such as machining, equipment storage, and oil and gas extraction. Detailed Implementation

[0027] The present invention will be further illustrated below with specific embodiments. These embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Those skilled in the art can make various modifications and alterations to the present invention without departing from its spirit and scope.

[0028] Preparation Example 1: Amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials, comprising the following steps: (1) Preparation of Bi2Se3 nanosheets: Weigh 1.05g BiCl3, add 23.1g diethylene glycol (mass ratio 22:1), mix and dissolve; add ammonia water to adjust pH to 8.5; add 1.26g Na2SO3 and 0.59g Se powder (BiCl3:Na2SO3:Se molar ratio 1:2:1.5) in sequence, and stir continuously for 15 min to obtain a uniform suspension; transfer the suspension to a 50mL polytetrafluoroethylene-lined reactor, add diethylene glycol to 80% of the reactor volume, seal and react at 165℃ for 22 h; cool naturally to room temperature, centrifuge at 8000 r / min, wash three times alternately with distilled water and anhydrous ethanol, and vacuum dry at 60℃ for 10 h to obtain Bi2Se3 nanosheets.

[0029] (2) Edge-selective hydroxylation activation: Take 1.0g of the above Bi2Se3 nanosheets, disperse them in 100mL of 5wt% H2O2 aqueous solution, add 50mL of deionized water, stir at room temperature for 40min; centrifuge at 8000r / min, and vacuum dry at 60℃ for 8h to obtain edge-selective hydroxylated Bi2Se3 nanosheets.

[0030] (3) Synthesis of amino-polypyrrole: Under nitrogen protection, weigh 0.068 g of pyrrole and 0.077 g of (1H-pyrrole-3-yl)methylamine, and dissolve them in 80 mL of anhydrous ethanol; control the temperature at 3℃ in an ice-water bath, and add 20 mL of ethanol solution containing 0.67 g of ferric chloride hexahydrate at a rate of 1 drop / second. After the addition is complete, continue stirring for 6.5 h; centrifuge, and wash repeatedly with deionized water until the filtrate is free of yellow Fe. 3+ No white silver chloride precipitate was found upon silver nitrate testing. The sample was washed twice with anhydrous ethanol and dried under vacuum at 60°C to obtain amino polypyrrole powder.

[0031] (4) Amino-polypyrrole bifunctional grafting: Weigh 1.0 g of amino-polypyrrole powder, disperse it in 120 mL of anhydrous dichloromethane, and cool it to 2 °C in an ice-water bath; add 0.054 g of 2-chloromethylbenzimidazole, 0.074 g of 3-chloropropionic acid, and 0.061 g of triethylamine; heat to 55 °C, stir and react for 3 h in the dark; wash twice with 2 wt% sodium bicarbonate aqueous solution, twice with deionized water, and once with anhydrous ethanol, and dry under vacuum to obtain an amino-polypyrrole precursor grafted with benzimidazole and carboxyl end groups.

[0032] (5) Esterification bridging: Take 0.5g of edge-selectively hydroxylated Bi2Se3 from (2), disperse it in 90 mL of anhydrous toluene and anhydrous dichloromethane (volume ratio 3:1) mixed solvent, and sonicate for 30 min; add 0.7g of amino polypyrrole precursor from (4) with benzimidazole group and carboxyl end group grafted on the side chain, and then add 0.12g DCC and 0.018g DMAP; seal the container and stir at room temperature in the dark for 18 h; centrifuge and wash once in hexane-anhydrous ethanol (volume ratio 1:3) mixed solvent, and vacuum dry at 60℃ to finally obtain amino polypyrrole covalently bridged bismuth selenide composite nanomaterial.

[0033] Preparation Example 2: Amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials, comprising the following steps: (1) Preparation of Bi2Se3 nanosheets: Weigh 1.05g BiCl3, add 18.9g diethylene glycol (mass ratio 18:1), mix and dissolve; add ammonia water to adjust the pH of the system to 8; add 0.94g Na2SO3 and 0.59g Se powder (BiCl3:Na2SO3:Se molar ratio 1:1.5:1.5) and stir for 15 min to obtain a uniform suspension; transfer the suspension to a 50mL polytetrafluoroethylene-lined reactor, add diethylene glycol to 80% of the reactor volume, seal and react at 150℃ for 20h; cool naturally to room temperature, centrifuge at 6000 r / min, wash 5 times alternately with distilled water and anhydrous ethanol, and vacuum dry at 60℃ for 8h to obtain Bi2Se3 nanosheets.

[0034] (2) Edge-selective hydroxylation activation: Take 1.0 g Bi2Se3 nanosheets, disperse them in 100 mL of 1 wt% H2O2 aqueous solution, add 50 mL of deionized water, stir at room temperature for 30 min; centrifuge at 8000 r / min, and vacuum dry at 60℃ for 6 h to obtain edge-selective hydroxylated Bi2Se3 nanosheets.

[0035] (3) Synthesis of amino-polypyrrole: Under nitrogen protection, 0.064 g of pyrrole and 0.077 g of (1H-pyrrole-3-yl)methylamine were weighed and dissolved in 80 mL of anhydrous ethanol; the temperature was controlled at 0℃ in an ice-water bath, and 20 mL of ethanol solution containing 0.53 g of ferric chloride hexahydrate was added dropwise at 0.5 drops / second. After the addition was completed, the mixture was stirred for 5 h; the mixture was centrifuged and washed repeatedly with deionized water until the filtrate was free of yellow Fe. 3+ No white silver chloride precipitate was found upon silver nitrate testing. The sample was washed three times with anhydrous ethanol and dried under vacuum at 60°C to obtain amino polypyrrole powder.

[0036] (4) Aminopolypyrrole bifunctional grafting: Weigh 1.0g of aminopolypyrrole powder, disperse it in 120mL of anhydrous dichloromethane, and cool it to 0℃ in an ice-water bath; add 0.050g of 2-chloromethylbenzimidazole, 0.064g of 3-chloropropionic acid and 0.061g of triethylamine; heat to 50℃ and react in the dark for 2h; wash 3 times with 2 wt% sodium bicarbonate aqueous solution, 3 times with deionized water and 2 times with anhydrous ethanol, and vacuum dry to obtain an aminopolypyrrole precursor grafted with benzimidazole and carboxyl end groups.

[0037] (5) Esterification bridging: Weigh 0.5g of edge-selectively hydroxylated Bi2Se3 from (2), disperse it in 90mL of anhydrous toluene and anhydrous dichloromethane (volume ratio 2:1) mixed solvent, and sonicate for 30min; add 0.7g of amino polypyrrole precursor from (4) with side chains simultaneously grafted with benzimidazole groups and carboxyl end groups, 0.12g of DCC, and 0.012g of DMAP; seal the container and stir at room temperature in the dark for 12h; centrifuge and wash twice in a hexane-anhydrous ethanol (volume ratio 1:1) mixed solvent, and vacuum dry at 60℃ to finally obtain amino polypyrrole covalently bridged bismuth selenide composite nanomaterials.

[0038] Preparation Example 3: Amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials, comprising the following steps: (1) Preparation of Bi2Se3 nanosheets: Weigh 1.05g BiCl3 and 29.4g diethylene glycol (mass ratio 28:1) and mix and dissolve; add ammonia water to adjust the pH of the system to 9; add 1.88g Na2SO3 and 0.59g Se powder (BiCl3:Na2SO3:Se molar ratio 1:2:1.5) in sequence, and stir continuously for 15min to obtain a uniform suspension; transfer the suspension to a 50mL polytetrafluoroethylene-lined reactor, add diethylene glycol to 80% of the reactor volume, seal and react at 180℃ for 24h; cool naturally to room temperature, centrifuge at 10000 r / min, wash with distilled water and anhydrous ethanol 6 times alternately, and vacuum dry at 60℃ for 12h to obtain Bi2Se3 nanosheets.

[0039] (2) Edge-selective hydroxylation activation: Take 1.0g of the above Bi2Se3 nanosheets, disperse them in 100mL of 10wt% H2O2 aqueous solution, add 50mL of deionized water, stir at room temperature for 60min; centrifuge at 8000 r / min, and vacuum dry at 60℃ for 10h to obtain edge-selective hydroxylated Bi2Se3 nanosheets.

[0040] (3) Synthesis of amino-polypyrrole: Under nitrogen protection, weigh 0.071 g of pyrrole and 0.077 g of (1H-pyrrole-3-yl)methylamine and dissolve them in 80 mL of anhydrous ethanol; control the temperature in an ice-water bath at 5 °C, and add 20 mL of ethanol solution containing 0.67 g of ferric chloride hexahydrate at a rate of 2 drops / second. After the addition is complete, continue stirring for 8 h; centrifuge and wash repeatedly with deionized water until the filtrate is free of yellow Fe. 3+ No white silver chloride precipitate was found upon silver nitrate testing. The sample was washed five times with anhydrous ethanol and dried under vacuum at 60°C to obtain amino polypyrrole powder.

[0041] (4) Aminopolypyrrole bifunctional grafting: Weigh 1.0g of aminopolypyrrole powder, disperse it in 120mL of anhydrous dichloromethane, and cool it to 5℃ in an ice-water bath; add 0.058g of 2-chloromethylbenzimidazole, 0.085g of 3-chloropropionic acid and 0.061g of triethylamine; heat to 60℃ and stir for 4h in the dark; wash 5 times with 2 wt% sodium bicarbonate aqueous solution, 5 times with deionized water and 3 times with anhydrous ethanol, and dry under vacuum to obtain an aminopolypyrrole precursor grafted with benzimidazole and carboxyl end groups.

[0042] (5) Esterification bridging: Take 0.5g of edge-selectively hydroxylated Bi2Se3 from (2), disperse it in 90mL of anhydrous toluene and anhydrous dichloromethane (volume ratio 4:1) mixed solvent, and sonicate for 30min; add 0.7g of amino polypyrrole precursor from (4) with benzimidazole group and carboxyl end group grafted on the side chain, and then add 0.12g DCC and 0.024g DMAP; seal the container and stir at room temperature in the dark for 24h; centrifuge and wash 3 times in hexane-anhydrous ethanol (volume ratio 1:5) mixed solvent, and vacuum dry at 60℃ to finally obtain amino polypyrrole covalently bridged bismuth selenide composite nanomaterial.

[0043] Comparative preparation example 1: (1) Weigh the raw materials according to Preparation Example 1: Weigh 1.05g BiCl3 and 23.1g diethylene glycol to prepare edge-selectively hydroxylated Bi2Se3; 0.068g pyrrole, 0.077g (1H-pyrrole-3-yl)methylamine and 0.67g ferric chloride hexahydrate to prepare amino polypyrrole powder.

[0044] (2) Weigh 0.5g of edge-selectively hydroxylated Bi2Se3 nanosheets and 0.75g of amino polypyrrole powder, mix them physically, add 100mL of anhydrous ethanol as a dispersion medium, and ultrasonically disperse for 30min; filter, and vacuum dry at 60℃ for 10h to obtain the physical blend composite material.

[0045] The difference between Preparation Example 1 and Preparation Example 2 is that: no covalent bridging structure was formed between aminopolypyrrole and Bi2Se3, and they were mixed only by physical means.

[0046] Comparative preparation example 2: (1) The same materials were used as in Preparation Example 1 to prepare edge-selectively hydroxylated Bi2Se3 nanosheets.

[0047] (2) Under nitrogen protection, weigh 0.068 g of pyrrole and 0.077 g of (1H-pyrrole-3-yl)methylamine and dissolve them in anhydrous ethanol. Add ferric chloride hexahydrate ethanol solution at a rate of 1 drop / second under ice-water bath conditions, stir for 6.5 h, and obtain amino polypyrrole powder after washing and drying.

[0048] (3) Take 1.0 g of amino polypyrrole and disperse it in 120 mL of anhydrous dichloromethane. Place it in an ice-water bath at 2 °C. Add only 0.074 g of 3-chloropropionic acid and 0.061 g of triethylamine, without adding 2-chloromethylbenzimidazole. React at 55 °C in the dark for 3 h. Wash and dry to obtain polypyrrole with only carboxyl groups and no benzimidazole side chains.

[0049] (4) Take 0.5g of edge-selectively hydroxylated Bi2Se3 and 0.7g of amino polypyrrole powder and disperse them in a mixed solvent of anhydrous toluene and anhydrous dichloromethane. Add 0.12g of DCC and 0.018g of DMAP and react at room temperature for 18h. After washing and drying, a covalent composite product without grafted benzimidazole groups is obtained.

[0050] The difference between Preparation Example 2 and Preparation Example 1 is that the amino-polypyrrole side chain does not have benzimidazole groups grafted on it, and only contains carboxyl end groups.

[0051] Comparative preparation example 3: (1) Bi2Se3 nanosheets were prepared according to the method of Preparation Example 1.

[0052] (2) Weigh 1.0g of Bi2Se3 nanosheets and disperse them in 100mL of 5 wt% H2O2 aqueous solution. Stir for 120min to hydroxylate the entire surface of the nanosheets. Centrifuge and vacuum dry at 60℃ for 8h to obtain non-selectively hydroxylated Bi2Se3 nanosheets.

[0053] (3) The subsequent steps are the same as (3) to (5) of Preparation Example 1.

[0054] The difference between Preparation Example 3 and Preparation Example 1 is that the Bi2Se3 nanosheets underwent extensive oxidation treatment, resulting in hydroxylation of the surface and edges, which destroyed the layered structure of the nanosheets.

[0055] Example 1: An oily corrosion inhibitor composition comprising the following raw materials in parts by weight: 680g of 150SN mineral oil base oil; 20g of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial of Preparation Example 1; 23g of T154 polyisobutylene succinimide dispersion stabilizer; 4g of 2,6-di-tert-butyl-p-cresol antioxidant; and 32g of ethylene glycol monobutyl ether acetate cosolvent; the 150SN base oil has a kinematic viscosity of 32 mmHg at 40°C. 2 / s, flash point 220℃. Preparation method is as follows: S1: Add 680g mineral oil, 23g T154, 4g antioxidant, and 32g cosolvent to a stirred tank, heat to 55℃, stir at 300r / min for 30 min, and dissolve all the additives evenly. S2: Cool the dissolved solution to 30℃, add 20g of amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial, disperse at 4000r / min for 30min, and take a sample to test the fineness of the slurry, which is 4.5μm (≤5μm). S3: After cooling the material obtained in S2 to room temperature, filter it through a 200-mesh filter, collect the filtrate, and let it stand for 18 hours to obtain the finished corrosion inhibitor.

[0056] Example 2: An oily corrosion inhibitor composition comprising the following raw materials in parts by weight: 700g of 150SN mineral oil, 15g of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial of Preparation Example 2, 20g of T154 polyisobutylene succinimide dispersion stabilizer, 3.5g of 2,6-di-tert-butyl-p-cresol antioxidant, and 30g of ethylene glycol monobutyl ether acetate cosolvent; 150SN base oil with a kinematic viscosity of 30 mmHg at 40°C. 2 / s, flash point 215℃. The preparation method is as follows: S1: Add 680g mineral oil, 23g T154, 4g antioxidant, and 32g cosolvent to a stirred tank, heat to 55℃, stir at 300r / min for 30min until all additives are dissolved evenly. S2: Cool the dissolved solution to 28℃, add 15g of amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial, disperse at 3500r / min for 30min, and take a sample to test the fineness of the slurry, which is 3.8μm (≤5μm). S3: After cooling the material obtained in S2 to room temperature, filter it through a 200-mesh filter, collect the filtrate, and let it stand for 15 hours to obtain the finished corrosion inhibitor.

[0057] Example 3: An oily corrosion inhibitor composition comprising the following raw materials in parts by weight: 660g of 150SN mineral oil base oil; 25g of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial of Preparation Example 3; 25g of T154 polyisobutylene succinimide dispersion stabilizer; 4.5g of 2,6-di-tert-butyl-p-cresol antioxidant; and 35g of ethylene glycol monobutyl ether acetate cosolvent; the 150SN base oil has a kinematic viscosity of 31 mmHg at 40°C. 2 / s, flash point 218℃. Preparation method is as follows: S1: Add 660g mineral oil, 25g T154, 4.5g antioxidant, and 35g cosolvent to a stirred tank, heat to 58℃, stir at 350 r / min for 35 min, and dissolve all the additives evenly. S2: Cool the dissolved solution to 32℃, add 25g of amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial, disperse at 4500 r / min for 30 min, and take a sample to test the fineness of the slurry, which is 4.2μm (≤5μm). S3: After cooling the material obtained in S2 to room temperature, filter it through a 200-mesh filter, collect the filtrate, and let it stand for 20 hours to obtain the finished corrosion inhibitor.

[0058] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the composite material is replaced with the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial in Comparative Preparation Example 1, which is a physical blend composite material.

[0059] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the composite material is replaced with the covalent composite product without grafted benzimidazole groups in Comparative Preparation Example 2.

[0060] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the composite material was replaced with the covalent composite product obtained in Comparative Preparation Example 3 (whose Bi2Se3 substrate was non-selectively over-hydroxylated).

[0061] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that no nano-corrosion inhibitors are added; it is a blank system consisting only of base oil and conventional additives.

[0062] Performance testing: The performance test results of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1: Table 1 Performance test results of each embodiment and comparative example

[0063] Data Analysis: The test results in Table 1 show that: In the accelerated dispersion stability test at 60℃ for 30 days, the dispersion retention rates of Examples 1-3 were 96.2%, 95.8%, and 94.7%, respectively, all maintaining a high level above 94%. Example 1 (using the preferred preparation method of Example 1) performed best, with a dispersion retention rate of 96.2%. The dispersion retention rate of Comparative Example 1 (physically blended composite material) was only 72.4%, a decrease of 23.8 percentage points compared to Example 1. This is because there is a lack of covalent bonding between aminopolypyrrole and Bi2Se3, resulting in a high interfacial free energy. During long-term standing, the physically mixed nanoparticles gradually aggregated and precipitated due to van der Waals forces. The dispersion retention rate of Comparative Example 3 (non-selectively hydroxylated Bi2Se3) was 81.6%, a decrease of 14.6 percentage points compared to Example 1. This is because excessive oxidation destroyed the layered structure of Bi2Se3, generating a large number of disordered hydroxyl groups on the nanosheet surface. These hydroxyl groups formed a hydrogen bond cross-linking network in the oily medium, exacerbating particle aggregation. It is noteworthy that Comparative Example 2 (without benzimidazole groups) achieved a dispersion retention rate of 93.1%, which is essentially the same as that of Examples 1-3. This indicates that the covalent bridging structure between aminopolypyrrole and Bi2Se3 is the decisive factor in ensuring the long-term non-agglomeration of nanoparticles, while the presence or absence of benzimidazole groups has little impact on dispersion stability. These results demonstrate that the covalent bridging structure successfully anchors the organic corrosion inhibitor to the surface of the inorganic carrier, fundamentally inhibiting the agglomeration of nanomaterials. This is the key to achieving long-term stable dispersion of the composition of this invention. The results of Comparative Example 3 further verify the necessity of edge-selective hydroxylation activation—only by providing an appropriate number of grafting sites at the edges without damaging the bulk structure of the nanosheets can both dispersion stability and physical barrier function be balanced.

[0064] The charge transfer resistance Rct test results show that the charge transfer resistance Rct of Examples 1-3 is 18560 Ω·cm, respectively. 2 17230Ω·cm 2 and 17890Ω·cm 2 The corrosion inhibition efficiencies were 88.4%, 87.5%, and 88.0%, respectively, all at an excellent level. Example 1 showed the best performance, attributed to its use of a combination of intermediate process parameters, achieving an optimal balance between the structural integrity of the nanomaterial and the grafting density of functional groups. In contrast, Comparative Example 1 had a corrosion inhibition efficiency of only 6850 Ω·cm. 2The corrosion inhibition efficiency was only 68.6%, a decrease of nearly 20 percentage points compared to Example 1. This is because there is a lack of electronic conduction channels between the corrosion inhibitor and the nanocarrier in the physical blend system. The electric field sensing ability of Bi2Se3 as a topological insulator cannot be effectively transferred to the amino polypyrrole molecules, resulting in the inability to establish a closed-loop feedback mechanism for self-sensing and adaptive regulation of the corrosion electric field. The corrosion inhibitor can only play a limited passive adsorption role. The Rct of Comparative Example 2 is 7920 Ω·cm. 2 The corrosion inhibition efficiency was 72.9%, significantly lower than that of Example 1. This result indicates that the absence of the benzimidazole group weakens the coordination bond strength between the corrosion inhibitor molecule and the metal surface, demonstrating the irreplaceable role of the benzimidazole group as an electron-rich nitrogen heterocyclic structure in forming a stable chemisorption film on the metal surface. The Rct of Comparative Example 3 was 8560 Ω·cm. 2 The corrosion inhibition efficiency was 74.9%, which was better than Comparative Examples 1 and 2, but still much lower than Example 1. This is because non-selective hydroxylation destroyed the layered structure of Bi2Se3, severely impairing the physical barrier function of the nanosheets. At the same time, excessive oxidation introduced a large number of defects on the surface of the nanosheets. These defects, as charge carrier recombination centers, weakened the electric field sensitivity of the surface states of the topological insulator, leading to the partial failure of the closed-loop feedback mechanism.

[0065] The test results in the salt spray test showed that the initial corrosion times of Examples 1-3 were 72h, 68h, and 70h, respectively, and the corrosion areas after 120h of salt spray corrosion were 3.2%, 4.1%, and 3.8%, respectively. Comparative Example 4 (blank system) had an initial corrosion time of only 18h, and a corrosion area as high as 65.4% after 120h, fully demonstrating the significant corrosion inhibition and protection effect of the composition of the present invention. The initial corrosion time of Example 1 was twice that of Comparative Example 1 (36h), and the corrosion area after 120h (3.2%) was only about one-sixth of that of Comparative Example 1 (18.6%). This significant difference stems from the fact that the corrosion inhibitor component in the physical blend system is prone to agglomeration and loss, and that there is a lack of electronic coupling between Bi2Se3 and aminopolypyrrole, which prevents the effective use of the electric field-enhanced adsorption function under the closed-loop self-feedback mechanism. The initial etching time (41 h) and corrosion area (15.2%) of Comparative Example 2 were also significantly worse than those of Example 1, demonstrating that the benzimidazole group, as a metal coordination adsorption functional group, plays a crucial role in resisting chloride ion corrosion. Although the initial etching time (45 h) and corrosion area (12.8%) of Comparative Example 3 were better than those of Comparative Examples 1 and 2, they were still far inferior to those of Example 1, indicating that the integrity of the Bi2Se3 layered structure is crucial for exerting its physical shielding function—once the layered structure is destroyed, the penetration path of the corrosive medium is shortened, and the barrier effect of the nanosheets is significantly weakened.

[0066] The results of the damp heat test showed that the damp heat rust prevention days of Examples 1-3 were 42 days, 38 days, and 40 days, respectively. Comparative Examples 1 (21 days), 2 (24 days), 3 (26 days), and 4 (10 days) were all significantly shorter than the Example systems. A good correlation was found between the damp heat rust prevention days and the salt spray corrosion area: the sample with the better protective effect (Example 1) had the smallest salt spray corrosion area (3.2%) and the longest damp heat rust prevention days (42 days); the sample with the worse protective effect (Comparative Example 4) had the largest corrosion area (65.4%) and the shortest rust prevention days (10 days). Example 1's damp heat rust prevention days were 21 days longer than Comparative Example 1, an improvement of 100%, fully demonstrating the reliability of the multiple synergistic corrosion inhibition mechanism achieved by the covalent bond structure of the present invention under long-term service conditions, maintaining excellent corrosion inhibition effects even in high-temperature and high-humidity environments.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications, equivalent substitutions, and improvements can be made to the technical solutions of the present invention without departing from the spirit and principles thereof, and all such modifications, equivalent substitutions, and improvements should be included within the protection scope of the present invention.

Claims

1. An oil-based corrosion inhibitor composition, characterized in that, The raw materials include the following parts by weight: 150SN mineral oil base oil: 65-73 parts; amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials: 1-3 parts; dispersant and stabilizer: 1.8-2.8 parts; antioxidant: 0.3-0.5 parts; cosolvent: 2.5-4 parts; The amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial is prepared by oxidative copolymerization of pyrrole and (1H-pyrrole-3-yl)methylamine under the action of ferric chloride hexahydrate, and the side chain has a primary amino group.

2. The oily corrosion inhibitor composition according to claim 1, characterized in that, The dispersant and stabilizer is polyisobutylene succinimide; the antioxidant is 2,6-di-tert-butyl-p-cresol; the cosolvent is ethylene glycol monobutyl ether acetate; and the kinematic viscosity of the 150SN mineral oil base oil at 40°C is 28-32 mmHg. 2 / s, flash point not lower than 200℃.

3. The oily corrosion inhibitor composition according to claim 1, characterized in that, The preparation method of the amino-polypyrrole covalently bridged bismuth selenide composite nanomaterial includes the following steps: (1) Preparation of Bi2Se3 nanosheets: BiCl3 was dissolved in diethylene glycol, and the pH was adjusted to 8-9 with ammonia water. Na2SO3 and Se powder were added in sequence and stirred to obtain a suspension. The suspension was transferred to a polytetrafluoroethylene reactor, and diethylene glycol was added to 80% of the reactor volume. The temperature was raised to 150-180℃ and the reaction was carried out for 20-24h. After cooling, the mixture was centrifuged at 6000-10000 r / min, washed 3-6 times with distilled water and anhydrous ethanol alternately, and vacuum dried for 8-12h to obtain Bi2Se3 nanosheets. (2) Edge-selective hydroxylation activation: Bi2Se3 nanosheets were dispersed in H2O2 aqueous solution, deionized water was added, and the mixture was stirred for 30-60 min; centrifuged and vacuum dried for 6-10 h to obtain edge-selective hydroxylated Bi2Se3 nanosheets; (3) Synthesis of amino-polypyrrole: Under nitrogen protection, pyrrole and (1H-pyrrole-3-yl)methylamine were dissolved in anhydrous ethanol, and the mixture was cooled to 0-5℃ in an ice-water bath. An ethanol solution containing ferric chloride hexahydrate was added dropwise at a rate of 0.5-2 drops / second, and the mixture was stirred for 5-8 hours. After centrifugation, the filtrate was washed with deionized water until no yellow Fe was visible. 3+ The filtrate showed no white precipitate when tested with silver nitrate solution. It was then washed with ethanol 2-5 times and dried to obtain amino polypyrrole powder. (4) Bifunctional grafting of amino polypyrrole: The obtained amino polypyrrole powder was dispersed in anhydrous dichloromethane; the temperature was lowered to 0-5℃, 2-chloromethylbenzimidazole, 3-chloropropionic acid and triethylamine were added, the temperature was raised to 50-60℃, and the reaction was stirred in the dark for 2-4 hours; the mixture was washed 2-5 times with sodium bicarbonate aqueous solution, 2-5 times with deionized water, and 1-3 times with anhydrous ethanol, and then dried under vacuum to obtain an amino polypyrrole precursor with benzimidazole group and carboxyl end group grafted on the side chain; (5) Esterification bridging: The edge-selectively hydroxylated Bi2Se3 obtained in (2) was dispersed in a mixed solvent of anhydrous toluene and anhydrous dichloromethane in a volume ratio of 2:1-4:1 and sonicated; an amino polypyrrole precursor with benzimidazole groups and carboxyl end groups grafted on the side chain was added, along with N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine, sealed, and stirred at room temperature for 12-24 h; the mixture was centrifuged and washed 1-3 times with a mixed solvent of n-hexane and anhydrous ethanol in a volume ratio of 1:1-1:5, and dried under vacuum to obtain amino polypyrrole covalently bridged bismuth selenide composite nanomaterials.

4. The oily corrosion inhibitor composition according to claim 3, characterized in that, The molar ratio of BiCl3, Na2SO3 and Se powder in (1) is 1:1.5-3:1.

5.

5. The oily corrosion inhibitor composition according to claim 3, characterized in that, The concentration of the H2O2 aqueous solution in (2) is 1 wt%-10 wt%.

6. The oily corrosion inhibitor composition according to claim 3, characterized in that, The molar ratio of pyrrole, (1H-pyrrole-3-yl)methylamine and ferric chloride hexahydrate in (3) is 1.8-2.0:1:2.2-2.

8.

7. The oily corrosion inhibitor composition according to claim 3, characterized in that, In step (4), the molar ratio of 2-chloromethylbenzimidazole, 3-chloropropionic acid and aminopolypyrrole is 0.3-0.35:0.6-0.8:1; the molar ratio of 2-chloromethylbenzimidazole, 3-chloropropionic acid and triethylamine is 0.20-0.28:0.46-0.56:1; and the concentration of the sodium bicarbonate aqueous solution is 2 wt%.

8. The oily corrosion inhibitor composition according to claim 3, characterized in that, In (5), the molar ratio of edge-selectively hydroxylated Bi2Se3, amino polypyrrole precursor with benzimidazole and carboxyl end groups on the side, N,N'-dicyclohexylcarbodiimide and 4-dimethylaminopyridine is 1:1.5-2.5:2.0-3.5:0.2-0.

7.

9. The method for preparing the oily corrosion inhibitor composition according to any one of claims 1-8, characterized in that, Includes the following steps: S1: Mix the 150SN mineral oil base oil, dispersant stabilizer, antioxidant and cosolvent according to the formula, heat to 50-60℃, and stir at 200-400r / min for 20-40min until completely dissolved; S2: Cool the dissolved solution to 25-35℃, add amino-polypyrrole covalently bridged bismuth selenide composite nanomaterials, and disperse at a high speed of 3000-5000r / min for 30min; S3: After cooling the material obtained in S2 to room temperature, filter it through a 200-mesh filter, collect the filtrate, and let it stand for 12-24 hours to obtain the finished corrosion inhibitor.

10. The method for preparing the oily corrosion inhibitor composition according to claim 9, characterized in that, After high-speed dispersion in S2, the slurry fineness is sampled and tested to be ≤5μm before entering the filtration process.

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