A benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor and its preparation method and application

Abstract

The invention discloses a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor and a preparation method and application thereof. The invention comprises the following steps: S1: dissolving 1-hydroxybenzotriazole in N,N-dimethylformamide, adding potassium carbonate and 1,6-dibromoalkane, reacting at room temperature until the reaction of the raw materials is complete as detected by TLC, stopping the reaction, and extracting, separating, and purifying to obtain an intermediate 1; S2: dissolving the intermediate 1 obtained in S1 in a triethylamine solvent, heating to a certain temperature, stirring and reacting until the reaction of the raw materials is complete as detected by TLC, stopping the reaction, and removing excess amine solvent by reduced pressure distillation to obtain the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor; the ionic liquid corrosion inhibitor acts on the surface of cold-rolled steel through physical adsorption and chemical adsorption to form a dense protective film, thereby effectively inhibiting corrosion of the cold-rolled steel surface by an acidic medium; and the ionic liquid corrosion inhibitor of the invention has the characteristics of low raw material price, simple synthesis method, mild reaction conditions, environmental friendliness, and excellent corrosion inhibition performance.

Description

Technical Field

[0001] The invention belongs to the technical field of metal corrosion inhibitors, and particularly relates to a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, a preparation method and an application thereof. Background Art

[0002] With the continuous development of modern industrial technology, metal materials have been widely used in various fields. However, metal materials are prone to corrosion when exposed to corrosive media such as acids, alkalis, and salts. Metal corrosion is prevalent in all areas of the national economy and science and technology, not only affecting the appearance and performance of metal materials, but also shortening their service life and even causing safety accidents. Therefore, how to effectively prevent the corrosion of metal materials has always been a key research focus in the industrial field. Adding corrosion inhibitors to corrosive media significantly reduces the corrosion rate of metals. Combined with their low dosage, low cost, and simple operation, they are one of the most commonly used methods for metal corrosion prevention.

[0003] Traditional corrosion inhibitors primarily fall into two categories: inorganic and organic. While inorganic inhibitors, such as chromates and nitrites, offer excellent corrosion inhibition, they also pose challenges such as high toxicity and severe environmental pollution. Organic inhibitors, such as benzotriazole and imidazoline, while less toxic, offer limited corrosion inhibition in certain media and are easily affected by factors such as temperature and pH. Due to drawbacks such as high cost, high toxicity, and environmental pollution, the use of traditional inorganic and organic inhibitors has gradually been limited.

[0004] In recent years, ionic liquids, as a new functional material, have shown promising application prospects in the field of corrosion inhibition. Ionic liquids offer advantages such as high thermal stability, high electrical conductivity, and strong dissolving power, making them excellent corrosion inhibitor carriers. As a new type of green and environmentally friendly metal corrosion inhibitor, ionic liquids have attracted considerable attention in recent years, with quaternary ammonium ionic liquids demonstrating particularly remarkable corrosion resistance.

[0005] Benzotriazole ionic liquids, in particular, are known for their ability to form coordinated bonds with metal surfaces due to the nitrogen atoms in the benzotriazole molecules, thereby forming a dense protective film on the metal surface that effectively inhibits metal corrosion reactions. However, current research on benzotriazole ionic liquid corrosion inhibitors is not yet in-depth, and research on combining them with quaternary ammonium salts to form benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitors is even less extensive. Quaternary ammonium salts, as a common ionic liquid cation, have excellent stability and solubility. Combining them with benzotriazole can further enhance the corrosion inhibition effect and stability of benzotriazole ionic liquid corrosion inhibitors.

[0006] Therefore, the present invention aims to develop a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor. This corrosion inhibitor combines the corrosion inhibition effect of benzotriazole with the characteristics of quaternary ammonium salt ionic liquid, and has excellent corrosion inhibition performance and good solubility. At the same time, the present invention also provides a simple preparation method, making the preparation process of this corrosion inhibitor more convenient and economical. In addition, the present invention also explores the application of this corrosion inhibitor in metal corrosion protection, electroplating industry, cooling system and environmental protection field, providing a new solution for corrosion protection in industrial field. Summary of the Invention

[0007] In view of this, the first object of the present invention is to provide a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor; the second object is to provide a preparation method of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor; the third object is to provide the use of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor in the preparation of a steel material corrosion inhibitor.

[0008] In order to achieve the above technical objectives, the present invention is implemented through the following technical solutions:

[0009] In a first aspect, the present invention provides a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, wherein the structural formula of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor is shown in formula (I):

[0010]

[0011] In a second aspect of the present invention, a method for preparing a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor is provided. The chemical reaction equation for preparing the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor is as follows:

[0012]

[0013] The preparation method of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor comprises the following steps:

[0014] S1: 1-Hydroxybenzotriazole is dissolved in N,N-dimethylformamide, potassium carbonate and 1,6-dibromoalkane are added, and the reaction is carried out at room temperature until the reaction of the raw material is complete as detected by TLC, then the reaction is stopped, and the intermediate is obtained through extraction, separation, and purification;

[0015] S2: dissolving the intermediate obtained in S1 in triethylamine solvent, heating to a certain temperature, stirring and reacting until the reaction of the raw materials is complete as detected by TLC, stopping the reaction, and removing the excess amine solvent by distillation under reduced pressure to obtain the pure benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor;

[0016] Preferably, the 1,6-dibromoalkane in S1 is 1,6-dibromohexane; the molar ratio of 1-hydroxybenzotriazole, potassium carbonate and 1,6-dibromohexane is 1:1.5:1;

[0017] Preferably, the specific operations of extraction, separation and purification in S1 are as follows: after the reaction is completed, 50 mL of ethyl acetate is added to the reaction system, and then the organic phase is washed three times with saturated brine, and then the organic phase is dried over anhydrous sodium sulfate, and finally the organic solvent is removed by distillation under reduced pressure to obtain a crude product; the crude product is purified by column chromatography to obtain a pure intermediate, and the eluent is petroleum ether / ethyl acetate = 10 / 1 (v / v);

[0018] Preferably, the certain temperature in S2 is 100-120° C. under standard atmospheric pressure.

[0019] The third aspect of the present invention provides an application of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, which is an application of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor in the preparation of a steel material corrosion inhibitor;

[0020] Preferably, the steel material is cold-rolled steel.

[0021] The beneficial effects of the present invention are:

[0022] 1) The present invention synthesizes a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, which combines the corrosion inhibition effect of benzotriazole with the characteristics of quaternary ammonium salt ionic liquid. It can form a dense protective layer on the surface of cold-rolled steel through the combined action of physical adsorption and chemical adsorption, thereby effectively inhibiting the corrosion of cold-rolled steel by acid media, and has excellent corrosion inhibition performance and good solubility.

[0023] 2) The preparation method disclosed in the present invention is simple and efficient, the raw materials are cheap and easily available, the reaction conditions are mild and safe, the product purification is simple, and it is suitable for industrial production.

[0024] 3) The benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor provided by the present invention can greatly improve the corrosion inhibition performance of cold-rolled steel in acidic media, and has good application prospects and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a chemical reaction equation for the preparation method of a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor of the present invention;

[0027] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor BTATEAB in Example 1 of the present invention;

[0028] Figure 3 is the carbon NMR spectrum of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor BTATEAB in Example 1 of the present invention;

[0029] Figure 4 This is a high-resolution mass spectrum of the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor BTATEAB in Example 1 of the present invention; DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments 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.

[0031] Example 1

[0032] (1) Synthesis of intermediates:

[0033] In a 50 mL single-necked round-bottom flask, 1-hydroxybenzotriazole (1 g, 7.40 mmol), potassium carbonate (1.53 g, 11.10 mmol), 1,6-dibromohexane (1.81 g, 7.40 mmol) and 5 mL of ultra-dry N,N-dimethylformamide were added. The reaction was stirred at room temperature until the reaction of the raw materials was complete as detected by TLC. The reaction was stopped, 50 mL of ethyl acetate was added to the reaction system, and the organic phase was washed 5 times with saturated brine and dried over anhydrous sodium sulfate. Finally, the organic solvent was removed by distillation under reduced pressure. The crude product was purified by column chromatography to obtain a pure intermediate (2.10 g, yield 95%). The NMR spectrum data are as follows.

[0034] 1 H NMR (400MHz, CDCl3): δ (ppm) = 8.02 (d, J = 8.4Hz, 1H, ArH), 7.57 (d, J = 8.4Hz, 1H, ArH), 7.54-7.50 (m, 1H, ArH), 7.41-7.37 (m, 1H, A rH),4.56(t,J=6.4Hz,2H,ArCH2),3.44(t,J=6.8Hz,2H,CH2Br),1.95-1.85(m,4H,ArCH2CH2,CH2CH2Br),1.63-1.53(m,4H,CH2).

[0035] (2) Synthesis of benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor BTATEAB:

[0036] The intermediate (1.00 g, 3.35 mmol) was added to a 50 mL single-necked round-bottom flask and dissolved in 10 mL of triethylamine. The temperature was raised to 120°C and stirred until the reaction was complete as detected by TLC. The reaction was stopped and the excess triethylamine solvent was removed by vacuum distillation to obtain pure ionic liquid corrosion inhibitor BTATEAB (1.25 g, 93% yield). Its NMR spectrum and high-resolution mass spectrometry data are shown below.

[0037] 1 H NMR (400MHz, CDCl3): δ (ppm) = 7.95 (d, J = 8.4Hz, 1H, ArH), 7.58 (d, J = 8.0Hz, 1H, ArH), 7.53–7 .49(m,1H,ArH),7.38-7.34(m,1H,Ar-H),4.51(t,J=6.0Hz,2H,ArOCH2),3.47(q,J=7.2Hz,6H ,NCH2CH3),3.35(t,J=8.8Hz,2H,NCH2CH2),1.87-1.77(m,4H,ArOCH2CH2,NCH2CH2),1.70-1 .63(m,2H,ArOCH2CH2CH2),1.55-1.47(m,2H,ArOCH2CH2CH2CH2),1.35(t,J=7.2Hz,9H,CH3); 13 C NMR (100MHz, CDCl3): δ (ppm) = 143.49, 128.32, 127.32, 124.87, 120.15, 108.87, 58 .31,57.55,53.59,27.79,26.07,25.20,21.99,18.50,8.17; HRMS(ESI)m / z:calcd for C 18 H 31 N4O,[M] + 319.2492,Found319.2492.

[0038] Example 2

[0039] (1) The ionic liquid BTATEAB was added to 1 mol / L dilute hydrochloric acid to prepare pickling solutions with BTATEAB concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, 50 mg / L, 60 mg / L, 70 mg / L, 80 mg / L, 90 mg / L, and 100 mg / L, respectively.

[0040] (2) At 25°C, the cold-rolled steel was completely immersed in the pickling solution prepared in Example 2(1) for corrosion inhibition for 12 hours, and then a weight loss test was performed on the hanging piece.

[0041] (3) According to the formula η%=[(ν0–ν i ) / ν0]×100% to calculate the corrosion inhibition efficiency, where ν0 is the metal corrosion rate without corrosion inhibitor, in gm -2 h -1 ν i is the metal corrosion rate after adding corrosion inhibitor, in gm -2 h -1 The experimental results of the corrosion inhibition performance test of the product of Example 1 as a corrosion inhibitor for cold-rolled steel are shown in Table 1.

[0042] Table 1 Corrosion inhibition performance of BTATEAB at different concentrations on cold-rolled steel in 1.0 mol / L HCl solution

[0043] Corrosion inhibitor concentration (mg / L) <![CDATA[Corrosion rate (gm -2 h -1 )]]> Corrosion inhibition rate (%) 0 3.6417 / 10 0.8333 77.12 20 0.5500 84.89 30 0.4500 87.64 40 0.4333 88.10 50 0.3333 90.85 60 0.2833 92.22 70 0.2833 92.22 80 0.2667 92.68 90 0.2367 93.59 100 0.2133 94.05

[0044] From the test results in Table 1, it can be found that the metal corrosion rate of cold-rolled steel without adding corrosion inhibitor is 3.6417gm -2 h -1 , indicating that 1 mol / L dilute hydrochloric acid solution has a strong corrosive effect on cold-rolled steel. When 10 mg / L of benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor is added, the corrosion inhibition efficiency of cold-rolled steel is significantly improved to 77.12%; thereafter, with the increase of BTATEAB corrosion inhibitor concentration, the corrosion inhibition efficiency of cold-rolled steel in the pickling solution gradually increases, and its maximum corrosion inhibition efficiency reaches 94.05%. This is attributed to the fact that the molecular structure of benzotriazole quaternary ammonium salt is tightly attached to the surface of cold-rolled steel through the combined action of physical adsorption and chemical adsorption, forming a protective film, which effectively prevents the overall or local corrosion of cold-rolled steel and achieves a better corrosion inhibition effect. This shows that the benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor provided by the present invention is an excellent metal corrosion inhibitor that can inhibit the corrosion of cold-rolled steel in acidic systems.

[0045] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, characterized in that, The structural formula is as follows (I):

2. The method for preparing a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor according to claim 1, wherein The following steps are involved: S1: Dissolve 1-hydroxybenzotriazole in N,N-dimethylformamide, add potassium carbonate and 1,6-dibromohexane, and react at room temperature until the reaction of the raw material is complete as determined by TLC. Stop the reaction, and obtain the intermediate through extraction, separation, and purification. S2: dissolving the intermediate obtained in S1 in triethylamine, heating to a certain temperature, stirring and reacting until the reaction of the raw materials is complete as detected by TLC, stopping the reaction, and removing the amine solvent by distillation under reduced pressure to obtain the benzotriazole quaternary ammonium salt corrosion inhibitor.

3. The preparation method of a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor according to claim 2, wherein In step S1, the molar ratio of 1-hydroxybenzotriazole, potassium carbonate and 1,6-dibromohexane is 1:1.5:

1.

4. The method for preparing a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor according to claim 2, wherein In step S1, the specific operations of the extraction, separation, and purification are as follows: after the reaction is completed, 50 mL of ethyl acetate is added to the reaction system, and then the organic phase is washed 5 times with saturated brine, and then the organic phase is dried with anhydrous sodium sulfate, and finally the organic solvent is removed by reduced pressure distillation to obtain a crude product; the crude product is purified by column chromatography to obtain a purified intermediate; the eluent is a combined solution of petroleum ether and ethyl acetate, and the volume ratio of petroleum ether to ethyl acetate is 10:

1.

5. The preparation method of a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor according to claim 2, wherein In step S2, the certain temperature is 100-120°C under standard atmospheric pressure.

6. An application of a benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor, characterized in that: The benzotriazole quaternary ammonium salt ionic liquid corrosion inhibitor described in claims 1-5 is used to prepare a corrosion inhibitor for steel materials.

7. The use of a benzotriazole quaternary ammonium salt corrosion inhibitor according to claim 6, characterized in that: The steel material is cold-rolled steel.

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