Preparation method and application of ionic liquid modified carbonized polymer dot corrosion inhibitor

Abstract

The invention provides a preparation method and application of an ionic liquid modified carbonized polymer dot corrosion inhibitor, the preparation method is designed according to a preparation method of carbon quantum dots from bottom to top, and a hydrothermal method is adopted to form carbonized polymerization dots through dehydration, cross-linking and carbonization reaction of amino of L-cysteine and carboxyl of imidazolyl ionic liquid; heteroatom-doped carbonized polymer dots rich in nitrogen and sulfur are prepared as the corrosion inhibitor.

Description

Technical Field

[0001] This invention relates to the field of preparation and application technology of corrosion inhibitors for carbon steel in sulfuric acid environment, and particularly to an ionic liquid modified carbonized polymer point corrosion inhibitor, its preparation method and application. Background Technology

[0002] Metal corrosion poses a threat to industrial equipment and human life. Corrosion inhibitors, as an economical method, are an effective way to prevent metal corrosion. However, toxic inhibitors, such as chromates and phosphorus-containing compounds, can harm human health and the environment after entering the environment, forcing researchers to develop new, highly efficient, and environmentally friendly inhibitors. As a member of the novel carbon-based functional nanomaterial family, carbon dots have proven to be an important candidate for corrosion inhibitors due to their water solubility, greater environmental friendliness, and excellent corrosion inhibition properties.

[0003] Patent CN114656960A discloses a lysine-based carbon quantum dot corrosion inhibitor, its preparation method, and its application. The carbon dot corrosion inhibitor is obtained by high-temperature pyrolysis of lysine and / or lysine derivatives. CN115432693A reports a nitrogen-doped carbon quantum dot corrosion inhibitor, its preparation method, and its application in pickling solutions for carbon steel. This method uses ammonium citrate as the carbon source, thiourea as the doping nitrogen source, and ethanol as the solvent, employing a hydrothermal method to synthesize nitrogen-doped carbon dots. CN113913830A discloses an environmentally friendly biomass carbon quantum dot corrosion inhibitor, its preparation method, and its application. It uses waste biomass powder as a precursor, synthesized via a one-step hydrothermal method, and after dialysis purification, obtains biomass CQDs corrosion inhibitor powder. Few patents report using amino acids as the carbon source. Ionic liquid-modified carbonized polymer dot corrosion inhibitors are prepared using ionic liquids as solvents, reactants, modifiers, and end-capping agents. Considering the regulatory role of ionic liquids (reaction media, catalysts, and functionalized molecules) in the synthesis and properties of carbon dots, and the influence of precursor properties and preparation conditions on the physical and chemical properties of carbon dots, functionalized ionic liquids (ILs) exhibit excellent corrosion inhibition effects. Combining the designability of ionic liquids with the unique advantages and properties of carbon dots, preparing carbonized polymer dots with excellent corrosion inhibition efficiency is an effective method. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems by providing a method for preparing an ionic liquid-modified carbonized polymer dot corrosion inhibitor and its application. The ionic liquid-modified carbonized polymer dots obtained by this method exhibit excellent corrosion inhibition properties. The prepared carbonized polymer dots have abundant functional groups on their surface, which facilitates the formation of an adsorption film on the metal surface through multi-anchor adsorption, thus inhibiting metal corrosion.

[0005] On the one hand, this invention provides a method for preparing an ionic liquid-modified carbonized polymer dot corrosion inhibitor. The preparation method is designed based on a bottom-up preparation method for carbon quantum dots. The amino group of L-cysteine ​​and the carboxyl group of imidazole ionic liquid are reacted with the amino group of L-cysteine ​​and the carboxyl group of imidazole ionic liquid through dehydration, crosslinking and carbonization to form carbonized polymer dots. Nitrogen and sulfur-rich heteroatom-doped carbonized polymer dots are prepared as corrosion inhibitors. On the other hand, the obtained carbonized polymer dots are applied as corrosion inhibitors to protect carbon steel in sulfuric acid media, and they exhibit significant corrosion inhibition effects.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor is characterized by comprising the following steps:

[0008] Step (1) Take 2g of ionic liquid and 5g of amino acid, stir them in a beaker to make them evenly mixed, then transfer the mixture to a PTFE liner, and then transfer the PTFE liner to a stainless steel hydrothermal reactor.

[0009] Step (2) Place the hydrothermal reactor in an oven and perform a solvothermal reaction for 4 hours;

[0010] After cooling to room temperature in step (3), add 80 mL of water to dissolve it, centrifuge at 8000 rpm, take the supernatant, and purify it using a 1000 Da dialysis bag;

[0011] Step (4) Take the above-mentioned dialysis solution, dry it, and finally obtain carbonized polymer dots.

[0012] Further, the ionic liquid described in step (1) is a 1-alkyl-3-carboxyethylimidazolium salt.

[0013] Furthermore, the amino acid mentioned in step (1) is selected from one of L-cysteine, methionine, and cystine.

[0014] Furthermore, the heat of dissolution in step (2) is preferably 160-220°C, more preferably 200°C, and most preferably 220°C.

[0015] Furthermore, the dialysis conditions described in step (3) are dialysis for 24 hours, with water changed every 6 hours.

[0016] Furthermore, in step (4), the drying conditions for the carbon dots are drying in a vacuum drying oven at 80°C.

[0017] Furthermore, the alkyl group in the 1-alkyl-3-carboxyethylimidazolium salt ionic liquid is selected from methyl, butyl, hexyl, and dodecyl; the anion is HSO4. - .

[0018] The ionic liquid-modified carbonized polymer dots prepared by the aforementioned method are used for corrosion inhibition in acidic media. Attached Figure Description

[0019] Figure 1 The solution used was 45# steel at 298K containing 0.5 mol·L⁻¹ CPDs-160, (b) CPDs-180, (c) CPDs-200, and (d) CPDs-220. -1 Nyqusit diagram in H2SO4 solution.

[0020] Figure 2 The solution used was 45# steel at 298K containing 0.5 mol·L⁻¹ CPDs-160, (b) CPDs-180, (c) CPDs-200, and (d) CPDs-220. -1 Polarization curves in H2SO4 medium. Specific Implementation

[0021] Example 1

[0022] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 220 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-220 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has an inhibition efficiency of 98.42%. See attached Nyquist diagram. Figure 1 The polarization curves are attached. Figure 2 .

[0023] Example 2

[0024] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 200 °C for 4 h. After cooling to room temperature, the solution was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-200 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has an inhibition efficiency of 96.09%. See attached Nyquist graph. Figure 1 The polarization curves are attached. Figure 2 .

[0025] Example 3

[0026] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 180 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-180 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has an inhibition efficiency of 95.83%. See attached Nyquist diagram. Figure 1 The polarization curves are attached. Figure 2 .

[0027] Example 4

[0028] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 160 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-160 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has an inhibition efficiency of 93.23%. See the attached Nyquist diagram. Figure 1 The polarization curves are attached. Figure 2 .

[0029] Example 5

[0030] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-butylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 160 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-160 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has a corrosion inhibition efficiency of 98.45%.

[0031] Example 6

[0032] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-dodecylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 160 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-160 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has a corrosion inhibition efficiency of 98.78%.

[0033] Example 7

[0034] 5 g of L-methionine and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 160 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-160 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has a corrosion inhibition efficiency of 94.23%.

[0035] Example 8

[0036] 5 g of L-cysteine ​​and 2 g of 1-carboxyethyl-3-methylimidazolium hydrogen sulfate were mixed thoroughly and placed in a 50 mL Teflon-lined container. The mixture was heated at 160 °C for 4 h. After cooling to room temperature, the product was dissolved in 80 mL of water. The solution was centrifuged at 8000 rpm for 15 minutes. Dialysis was performed using a 1000 Da dialysis bag for 24 h (water changed every 6 h). CPDs-160 was prepared using a vacuum drying method. Electrochemical results showed that at 0.5 mol·L⁻¹… -1 Add 150 mg·L⁻¹ to H₂SO₄ -1 The corrosion inhibitor has a corrosion inhibition efficiency of 93.65%.

[0037] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor, characterized in that, Includes the following steps: Step (1) Take 2g of ionic liquid and 5g of amino acid, stir them in a beaker to make them evenly mixed, then transfer the mixture to a PTFE liner, and then transfer the PTFE liner to a stainless steel hydrothermal reactor. Step (2) Place the hydrothermal reactor in an oven and perform a solvothermal reaction for 4 hours; After cooling to room temperature in step (3), add 80 mL of water to dissolve it, centrifuge at 8000 rpm, take the supernatant, and purify it using a 1000 Da dialysis bag; Step (4) Take the above-mentioned dialysis solution, dry it, and finally obtain carbonized polymer dots.

2. The method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor according to claim 1 is characterized in that, The ionic liquid mentioned in step (1) is a 1-alkyl-3-carboxyethylimidazolium salt.

3. The method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor according to claim 1 is characterized in that, The amino acid mentioned in step (1) is selected from one of L-cysteine, methionine, and cystine.

4. The method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor according to claim 1 is characterized in that, The heat of dissolution in step (2) is preferably 160-220℃, more preferably 200℃, and most preferably 220℃.

5. The method for preparing an ionic liquid-modified carbonized polymer pitting inhibitor according to claim 1 is characterized in that, The dialysis conditions described in step (3) are dialysis for 24 hours, with the water changed every 6 hours.

6. The method for preparing an ionic liquid-modified carbonized polymer pitting corrosion inhibitor according to claim 1 is characterized in that, The drying conditions for the carbon dots described in step (4) are drying in a vacuum drying oven at 80°C.

7. The alkyl group of the 1-alkyl-3-carboxyethylimidazolium salt ionic liquid according to claim 2 is selected from methyl, butyl, hexyl, and dodecyl; the anion is HSO4. - .

8. The application of ionic liquid-modified carbonized polymer dots prepared by the preparation method according to any one of claims 1-7 in corrosion inhibition in acidic media.

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