Carbon dioxide corrosion inhibitor, its preparation method and application
By preparing a corrosion inhibitor with an imidazoline Mannich base quaternary ammonium salt structure, the problem of unstable performance of existing corrosion inhibitors in high salinity environments was solved, and a superior corrosion inhibition effect was achieved in high salinity environments, with a corrosion inhibition rate of over 80%.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2026-03-24
AI Technical Summary
Existing carbon dioxide corrosion inhibitors are not stable enough in high salinity environments, and their corrosion inhibition effect is significantly reduced, making them unable to effectively protect metal equipment.
Corrosion inhibitors with an imidazoline Mannich base quaternary ammonium salt structure were prepared by quaternization reaction using α-lipoic acid, diethylenetriamine, formaldehyde, 2-naphthyl ethyl ketone, and benzyl chloride as raw materials, thereby enhancing their adsorption and film-forming properties in highly mineralized media.
The prepared corrosion inhibitor can still effectively block corrosive ions in high salinity environments, maintaining excellent corrosion inhibition performance with a corrosion inhibition rate of over 80%.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of oil and gas field corrosion protection, and particularly relates to a carbon dioxide corrosion resistant corrosion inhibitor, a preparation method and application thereof. BACKGROUND
[0002] CO2 flooding technology is widely used in oil and gas field exploitation, and CO2 injection into a reservoir can make crude oil expand in volume, reduce crude oil viscosity, reduce oil-water interfacial tension and capillary pressure, thereby improving the crude oil recovery rate.
[0003] However, in the process of oil and gas exploitation, the ground and underground equipment basically adopts metal materials. After CO2 is dissolved in formation water, it can cause corrosion perforation of oil pipes and corrosion failure of mechanical equipment; in the case of the same pH, the total acidity of carbonic acid is higher than that of hydrochloric acid, and the carbonic acid has stronger corrosiveness than the hydrochloric acid on oil well pipe materials and ground gathering and transportation systems, thereby causing huge economic losses and safety accidents.
[0004] In actual production and transportation, CO2 corrosion protection is often performed by correct material selection, coating, plating, process improvement and addition of corrosion inhibitors. The equipment made of anticorrosive materials or coating has a high cost, which greatly increases the operation cost in the process of oil exploitation.
[0005] Therefore, the addition of a corrosion inhibitor in the process of flooding, injection and production can form one or more protective films on the metal surface, block the contact between acid and metal, reduce the corrosion rate and protect the metal materials. At present, the corrosion inhibitors for carbon dioxide corrosion mainly include imidazoline corrosion inhibitors, Mannich base corrosion inhibitors and pyridine corrosion inhibitors, but the performance superiority and stability of these corrosion inhibitors still need to be improved, especially the corrosion inhibition effect of the existing corrosion inhibitors will decrease significantly in a high salinity environment. SUMMARY
[0006] The present application aims to solve the problem that the performance of the existing corrosion inhibitor for carbon dioxide corrosion is not stable enough, and the corrosion inhibition effect decreases significantly in a high salinity environment. The present application aims to provide a corrosion inhibitor which is effective against carbon dioxide corrosion and has excellent corrosion inhibition effect in a high salinity environment, a preparation method thereof and application thereof. The corrosion inhibitor provided by the present application has stable structure, good corrosion inhibition effect and simple preparation method, and the corrosion inhibition rate is greater than 80%.
[0007] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions.
[0008] Firstly, in the first aspect, the present application provides a carbon dioxide corrosion resistant corrosion inhibitor, and the raw materials of the corrosion inhibitor include alpha-lipoic acid, diethylenetriamine, formaldehyde, 2-naphthyl ethyl ketone and benzyl chloride.
[0009] The molar ratio of the alpha-lipoic acid, diethylene triamine, formaldehyde, 2-naphthylacetophenone, benzyl chloride is 1.0-1.2:0.8-1.2:1.2-2.0:1.0-1.4:1.0-1.4.
[0010] Secondly, in the second aspect, the application provides a preparation method of the corrosion inhibitor as described above, comprising the following steps:
[0011] S1, taking raw materials according to a molar ratio, mixing alpha-lipoic acid and diethylene triamine, and reacting to obtain a first product;
[0012] S2, mixing formaldehyde, 2-naphthylacetophenone and the first product, and reacting to obtain a second product;
[0013] S3, mixing benzyl chloride and the second product, and reacting to obtain a finished product corrosion inhibitor.
[0014] Further, in the step S1, the reaction comprises reacting at 140-160 DEG C for 2-5 h, and then reacting at 190-210 DEG C for 2-5 h.
[0015] Further, in the step S1, the reaction is carried out in a xylene environment under a nitrogen atmosphere.
[0016] Further, in the step S2, the reaction temperature is 60-90 DEG C, and the reaction time is 3-8 h.
[0017] Further, in the step S2, ethanol is used as a solvent during mixing.
[0018] Further, in the step S3, the reaction temperature is 90-110 DEG C, and the reaction time is 2-6 h.
[0019] Further, the step S3 further comprises vacuum drying treatment after the reaction.
[0020] Further, the treatment temperature of the vacuum drying treatment is 70-90 DEG C, and the treatment time is 0.5-1 h.
[0021] In addition, in the third aspect, the application also provides a use of the corrosion inhibitor as described above in preventing carbon dioxide corrosion.
[0022] Compared with the prior art, the application has the following beneficial effects:
[0023] 1. The anti-carbon dioxide corrosion inhibitor provided by the present application, first, diethylenetriamine is selected as a raw material to prepare the inhibitor, so that the inhibitor molecules can form imidazoline rings to be adsorbed on the metal surface; further, the introduction of alpha-lipoic acid monomer enhances the hydrophobicity of the inhibitor, and the introduction of S further enhances the adsorption capacity of the inhibitor molecules. The 2-naphthalenyl acetone monomer is added at the same time, the naphthalene ring further enhances the hydrophobicity of the inhibitor molecules, increases the coverage area of the inhibitor, and further enhances the corrosion inhibition performance of the inhibitor. The introduction of benzyl chloride monomer can modify the inhibitor molecules, enhance the water solubility, film-forming property and corrosion inhibition performance of the inhibitor, and further achieve the purpose of slowing down the corrosion.
[0024] The structure of the inhibitor of the present application is shown in Figure 2 , which has imidazoline Mannich base quaternary ammonium salt structure and multiple ring structures, so the inhibitor of the present application has good film-forming property.
[0025] Further referring to Figure 2 , the imidazoline structure of the inhibitor of the present application has nitrogen-containing heterocyclic structure, which can effectively enhance the adsorption of the inhibitor.
[0026] Further referring to Figure 2 , the inhibitor of the present application has Mannich base structure, the amino group (—N—) in the Mannich base molecule forms an electron-rich conjugated system with the benzene ring, coordinates with the metal surface empty orbital through the lone pair of electrons, and forms a firm chemical adsorption layer. This adsorption layer can still exist stably in a high salinity environment, and blocks the contact of Cl - , SO4 2- and other corrosive ions with the metal. Therefore, this structure can enhance the corrosion inhibition performance of the inhibitor in a high salinity medium.
[0027] In summary, the inhibitor provided by the present application can effectively resist carbon dioxide corrosion, has stable performance, and still has superior corrosion inhibition effect in a high salinity environment.
[0028] 2. The preparation method of the anti-carbon dioxide corrosion inhibitor provided by the present application, which is relatively simple and convenient for wide application. The preparation method effectively enhances the water solubility, film-forming property and corrosion inhibition performance of the inhibitor through quaternization reaction, and the corrosion inhibition effect is still superior in a high salinity environment.
[0029] The prepared inhibitor has excellent performance, the inhibitor has imidazoline Mannich base quaternary ammonium salt structure and multiple ring structures to enhance the film-forming property of the inhibitor; the inhibitor has nitrogen-containing heterocyclic structure to effectively enhance the adsorption of the inhibitor; and the inhibitor has Mannich base structure to enhance the corrosion inhibition performance of the inhibitor in a high salinity medium.
[0030] 3. The application of the anti-carbon dioxide corrosion inhibitor provided by the application can be applied to the corrosion prevention of equipment and / or pipelines containing carbon dioxide, and has wide application space and strong superiority. BRIEF DESCRIPTION OF DRAWINGS
[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0032] Figure 1 The infrared spectrum of the anti-carbon dioxide corrosion inhibitor provided by the application;
[0033] Figure 2 The structural formula of the anti-carbon dioxide corrosion inhibitor provided by the application. DETAILED DESCRIPTION
[0034] The various exemplary embodiments of the present application will now be described in detail, which should not be considered as limiting the present application, but should be understood as a more detailed description of some aspects, characteristics and embodiments of the present application.
[0035] It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the present application. In addition, for the numerical range in the present application, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in the stated range and any other stated value or intermediate value in the stated range is also included in the present application. The upper limit and the lower limit of these smaller ranges can be independently included or excluded from the range.
[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are concerned. In the event of conflict between the content of the specification and any incorporated document, the content of the specification controls.
[0037] Many modifications and variations of the present application specification can be made without departing from the scope or spirit of the present application, which will be apparent to those skilled in the art. Other embodiments obtained from the specification of the present application will be apparent to those skilled in the art. The specification and examples of the present application are only exemplary.
[0038] As used herein, "comprise", "comprising", "having", "including", "contain", "containing", "include" and the like are open-ended terms that are intended to mean including but not limited to.
[0039] Firstly, in the first aspect, the present application provides an anti-carbon dioxide corrosion inhibitor, raw materials of the inhibitor include, alpha-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride; the molar ratio of the alpha-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride is 1.0~1.2:0.8~1.2:1.2~2.0:1.0~1.4:1.0~1.4. The structural formula of the inhibitor is shown in Figure 2 .
[0040] The molar ratio of the alpha-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride is preferably 1.1:0.9~1.1:1.4~1.8:1.1~1.3:1.1~1.3; further preferably 1.1:1.0:1.5:1.2:1.2.
[0041] It can be understood that the inhibitor of the present application can form an imidazoline ring by taking diethylene triamine as raw material, so that the inhibitor molecules can be adsorbed on the steel surface. The introduction of alpha-lipoic acid monomer enhances the hydrophobicity of the inhibitor, and the introduction of S further enhances the adsorption capacity of the inhibitor molecules. At the same time, the naphthalene ring of 2-naphthyl ethyl ketone monomer further enhances the hydrophobicity of the inhibitor molecules, increases the coverage area of the inhibitor, and further enhances the corrosion inhibition performance of the inhibitor. The introduction of benzyl chloride monomer can modify the inhibitor molecules, enhance the water solubility, film forming property and corrosion inhibition performance of the inhibitor, and further achieve the purpose of slowing down the corrosion.
[0042] Referring to Figure 2 , the inhibitor of the present application has an imidazoline Mannich base quaternary ammonium salt structure, and multiple ring structures exist, so the inhibitor of the present application has good film forming property.
[0043] Further referring to Figure 2 , the imidazoline structure of the inhibitor of the present application has a nitrogen-containing heterocyclic structure, which can effectively enhance the adsorption of the inhibitor.
[0044] Further referring to Figure 2 , the inhibitor of the present application has a Mannich base structure, the amino group (—N—) in the Mannich base molecule forms an electron-rich conjugated system with the benzene ring, coordinates with the metal surface empty orbital through the lone pair of electrons, and forms a firm chemical adsorption layer. This adsorption layer can still exist stably in a high salinity environment, blocking the contact of Cl - , SO4 2- and other corrosive ions with the metal. Therefore, this structure can enhance the corrosion inhibition performance of the inhibitor in a high salinity medium.
[0045] Secondly, in a second aspect, the present invention provides a method for preparing the corrosion inhibitor as described above, comprising the following steps:
[0046] S1. Take the raw materials in molar ratio, mix α-lipoic acid and diethylenetriamine, and react to obtain the first product;
[0047] S2. Formaldehyde, 2-naphthyl ethyl ketone, and the first product are mixed and reacted to give the second product.
[0048] S3. Mix benzyl chloride and the second product, and react to obtain the finished corrosion inhibitor.
[0049] It is understood that the preparation method of the carbon dioxide corrosion inhibitor provided by this invention is relatively simple and easy to apply widely. The preparation method effectively enhances the water solubility, film-forming properties, and corrosion inhibition performance of the inhibitor through a quaternization reaction. The prepared inhibitor exhibits excellent performance; it possesses an imidazoline Mannich base quaternary ammonium salt structure, and the presence of multiple ring structures enhances its film-forming properties; the nitrogen-containing heterocyclic structure effectively enhances its adsorption capacity; and the Mannich base structure enhances its corrosion inhibition performance in highly salinized media.
[0050] In some embodiments of the present invention, in step S1, the molar ratio of α-lipoic acid, diethylenetriamine, formaldehyde, 2-naphthyl ethyl ketone, and benzyl chloride is 1.0~1.2:0.8~1.2:1.2~2.0:1.0~1.4:1.0~1.4.
[0051] The preferred molar ratio of α-lipoic acid, diethylenetriamine, formaldehyde, 2-naphthyl ethyl ketone, and benzyl chloride is 1.1:0.9~1.1:1.4~1.8:1.1~1.3:1.1~1.3; more preferably 1.1:1.0:1.5:1.2:1.2.
[0052] In some embodiments of the present invention, step S1 includes reacting at 140-160°C for 2-5 hours, and then reacting at 190-210°C for 2-5 hours.
[0053] In step S1, the reaction is further preferably carried out by reacting at 145~155℃ for 3~4 hours, and then at 195~205℃ for 3~4 hours.
[0054] Furthermore, preferably, the reaction is carried out at 150°C for 3.5 hours first, and then at 200°C for 3.5 hours.
[0055] In some embodiments of the present invention, in step S1, xylene is used as a water-carrying agent and the reaction is carried out in a nitrogen atmosphere.
[0056] In some embodiments of the present application, the step S1 is used to prepare the imidazoline ring structure.
[0057] In some embodiments of the present application, the reaction temperature in the step S2 is 60-90℃, and the reaction time is 3-8h.
[0058] In the step S2, the reaction temperature is preferably 65-80℃, and more preferably 70℃.
[0059] In the step S2, the reaction time is preferably 3-8h, and more preferably 4-6h, and more preferably 5h.
[0060] In some embodiments of the present application, in the step S2, ethanol is used as the solvent during the mixing.
[0061] In some embodiments of the present application, the step S2 is a Mannich base reaction.
[0062] In some embodiments of the present application, in the step S3, the reaction temperature is 90-110℃, and the reaction time is 2-6h.
[0063] In the step S3, the reaction is a quaternization reaction.
[0064] In the step S3, the reaction temperature is more preferably 95-105℃, and more preferably 100℃.
[0065] In the step S3, the reaction time is more preferably 3-5h, and more preferably 4h.
[0066] In some embodiments of the present application, the step S3 further comprises a vacuum drying treatment after the reaction.
[0067] In some embodiments of the present application, the treatment temperature of the vacuum drying treatment is 70-90℃, and the treatment time is 0.5-1h.
[0068] The treatment temperature of the vacuum drying treatment is more preferably 75-85℃, and more preferably 80℃. The treatment time of the vacuum drying treatment is more preferably 0.6-0.8h, and more preferably 0.7h.
[0069] In addition, in the third aspect, the present application also provides a use of the above-mentioned corrosion inhibitor in preventing carbon dioxide corrosion.
[0070] It can be understood that the use of the corrosion inhibitor against carbon dioxide corrosion provided by the present application has a wide application space and strong superiority in preventing corrosion of equipment and / or pipelines containing carbon dioxide.
[0071] Example 1
[0072] A carbon dioxide corrosion inhibitor, which is composed of the following raw material components: α-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride in a molar ratio of 1.1:1.0:1.5:1.2:1.2.
[0073] Example 2
[0074] A carbon dioxide corrosion inhibitor, which is composed of the following raw material components: α-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride in a molar ratio of 1.0:1.2:1.2:1.4:1.0.
[0075] Example 3
[0076] A carbon dioxide corrosion inhibitor, which is composed of the following raw material components: α-lipoic acid, diethylene triamine, formaldehyde, 2-naphthyl ethyl ketone, benzyl chloride in a molar ratio of 1.2:0.8:2.0:1.0:1.4.
[0077] Example 4
[0078] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:
[0079] (1) 5.16g α-lipoic acid, 2.58g diethylene triamine are dissolved in a three-necked flask, 40ml xylene is added as a water carrying agent, and then the mixture is reacted at 150℃ for 2h and at 200℃ for 2h in a nitrogen environment, xylene is removed, and a first product is obtained;
[0080] (2) The first product is added to a three-necked flask, dissolved in 30ml ethanol, 1.50g formaldehyde and 5.11g 2-naphthyl ethyl ketone are added, and the mixture is continuously reacted at 70℃ for 5h to obtain a second product;
[0081] (3) 3.80g benzyl chloride is mixed with the second product, and the mixture is subjected to quaternary ammonium reaction at 100℃ for 3h, and then is moved into a vacuum oven and dried at 80℃ for 0.5h to obtain the corrosion inhibitor 1.
[0082] Example 5
[0083] A preparation method of a carbon dioxide corrosion inhibitor, comprising the following steps:
[0084] (1) 5.16g α-lipoic acid, 3.10g diethylene triamine are dissolved in a three-necked flask, 40ml xylene is added as a water carrying agent, and then the mixture is reacted at 150℃ for 2h and at 200℃ for 2h in a nitrogen environment, xylene is removed, and a first product is obtained;
[0085] (2) The first product is added to a three-necked flask, dissolved in 30 ml of ethanol, 1.50 g of formaldehyde and 5.11 g of 2-naphthyl ethanone are added, and the reaction is continued at 70°C for 5 h to obtain a second product;
[0086] (3) 3.80 g of benzyl chloride is mixed with the second product, and quaternary ammonium reaction is carried out at 100°C for 3 h, and then the mixture is moved into a vacuum oven and dried at 80°C for 0.5 h to obtain the corrosion inhibitor 2.
[0087] Example 6
[0088] A preparation method of a corrosion inhibitor against carbon dioxide corrosion, the steps are as follows:
[0089] (1) 5.16 g of α-lipoic acid and 2.58 g of diethylene triamine are dissolved in a three-necked flask, 40 ml of xylene is added as a water carrying agent, and the reaction is carried out at 150°C for 2 h and then at 200°C for 2 h in a nitrogen environment, and then the xylene is removed to obtain a first product;
[0090] (2) The first product is added to a three-necked flask, dissolved in 30 ml of ethanol, 1.50 g of formaldehyde and 4.26 g of 2-naphthyl ethanone are added, and the reaction is continued at 70°C for 5 h to obtain a second product;
[0091] (3) 3.80 g of benzyl chloride is mixed with the second product, and quaternary ammonium reaction is carried out at 100°C for 3 h, and then the mixture is moved into a vacuum oven and dried at 80°C for 0.5 h to obtain the corrosion inhibitor 3.
[0092] Example 7
[0093] A preparation method of a corrosion inhibitor against carbon dioxide corrosion, the steps are as follows:
[0094] (1) 5.16 g of α-lipoic acid and 3.10 g of diethylene triamine are dissolved in a three-necked flask, 40 ml of xylene is added as a water carrying agent, and the reaction is carried out at 150°C for 2 h and then at 200°C for 2 h in a nitrogen environment, and then the xylene is removed to obtain a first product;
[0095] (2) The first product is added to a three-necked flask, dissolved in 30 ml of ethanol, 1.50 g of formaldehyde and 4.26 g of 2-naphthyl ethanone are added, and the reaction is continued at 70°C for 5 h to obtain a second product;
[0096] (3) 3.80 g of benzyl chloride is mixed with the second product, and quaternary ammonium reaction is carried out at 100°C for 3 h, and then the mixture is moved into a vacuum oven and dried at 80°C for 0.5 h to obtain the corrosion inhibitor 4.
[0097] Example 8
[0098] A preparation method of a corrosion inhibitor against carbon dioxide corrosion, the steps are as follows:
[0099] (1) 5.16 g of α-lipoic acid and 3.10 g of diethylene triamine were dissolved in a three-necked flask, 40 ml of xylene was added as a water carrying agent, and the mixture was reacted at 150°C for 2 h and then at 200°C for 2 h under a nitrogen atmosphere. The xylene was removed to obtain a first product;
[0100] (2) The first product was added to a three-necked flask, dissolved in 30 ml of ethanol, and 1.50 g of formaldehyde and 4.26 g of 2-naphthyl ethyl ketone were added. The mixture was continuously reacted at 70°C for 5 h to obtain a second product;
[0101] (3) 3.16 g of benzyl chloride was mixed with the second product, and the mixture was subjected to quaternary ammonium reaction at 100°C for 3 h. The mixture was then moved into a vacuum oven and dried at 80°C for 0.5 h under vacuum to obtain the corrosion inhibitor 5.
[0102] Example 9
[0103] A method for preparing a corrosion inhibitor against carbon dioxide corrosion, comprising the following steps:
[0104] (1) 5.16 g of α-lipoic acid and 3.10 g of diethylene triamine were dissolved in a three-necked flask, 40 ml of xylene was added as a water carrying agent, and the mixture was reacted at 150°C for 2 h and then at 200°C for 2 h under a nitrogen atmosphere. The xylene was removed to obtain a first product;
[0105] (2) The first product was added to a three-necked flask, dissolved in 30 ml of ethanol, and 0.90 g of formaldehyde and 4.26 g of 2-naphthyl ethyl ketone were added. The mixture was continuously reacted at 70°C for 5 h to obtain a second product;
[0106] (3) 3.80 g of benzyl chloride was mixed with the second product, and the mixture was subjected to quaternary ammonium reaction at 100°C for 3 h. The mixture was then moved into a vacuum oven and dried at 80°C for 0.5 h under vacuum to obtain the corrosion inhibitor 6.
[0107] Example 10
[0108] A method for preparing a corrosion inhibitor against carbon dioxide corrosion, comprising the following steps:
[0109] (1) 5.16 g of α-lipoic acid and 2.58 g of diethylene triamine were dissolved in a three-necked flask, 40 ml of xylene was added as a water carrying agent, and the mixture was reacted at 150°C for 2 h and then at 200°C for 2 h under a nitrogen atmosphere. The xylene was removed to obtain a first product;
[0110] (2) The first product was added to a three-necked flask, dissolved in 30 ml of ethanol, and 0.90 g of formaldehyde and 4.26 g of 2-naphthyl ethyl ketone were added. The mixture was continuously reacted at 70°C for 5 h to obtain a second product;
[0111] (3) 3.80 g of benzyl chloride was mixed with the second product, and quaternary ammonium was reacted at 100°C for 3 h, and then was moved into a vacuum oven and dried at 80°C for 0.5 h to obtain corrosion inhibitor 7.
[0112] Test Example 1
[0113] 1.1 Test Design
[0114] The corrosion inhibitors prepared in Examples 4 to 10 were taken as samples, and the corrosion inhibition performance of each group of samples was determined respectively. A blank control was set: no corrosion inhibitor was added.
[0115] The specific test operation was as follows:
[0116] The test medium used was self-prepared simulated water, and the content of each component of the simulated water is shown in Table 1.
[0117] The simulated water was prepared according to Table 1, and carbon dioxide was introduced until saturation; the test piece used was an N80 steel piece with an outer size of 50 mm x 10 mm x 3 mm; and the test container was a 1 L capacity bottle.
[0118] The test piece was first cleaned with filter paper, and then was placed in petroleum ether with a boiling range of 60°C, and the surface grease of the test piece was removed with absorbent cotton, and then was placed in anhydrous ethanol for about 5 min for further degreasing and dehydration. The test piece was taken out, placed on filter paper, and dried with cold air, and then was wrapped with filter paper, and was stored in a desiccator for 1 h before measuring the size and weighing, with an accuracy of 0.1 mg.
[0119] The prepared corrosion inhibitor solution was added into the test container with a pipette according to the designed mass concentration value.
[0120] The test container was purged with nitrogen to remove air, and then the test medium was introduced into the test container with a rubber tube. The rubber tube should be inserted below the liquid surface and close to the bottle wall to prevent air from entering. Then the rubber tube was gradually raised as the liquid level rose, and the test piece was hung in when the required volume of test medium was added, and the bottle stopper was tightly sealed. At the same time, a blank test without corrosion inhibitor was performed. Three test pieces were hung in the test container. The test pieces were not allowed to contact the container wall, and the distance between the test pieces should be more than 1 cm, and the upper end of the test piece should be more than 3 cm from the liquid surface.
[0121] The test device was placed in a water bath at a set temperature for 72 h. The test pieces that had reached the test period were taken out, and the surface corrosion state and corrosion product adhesion were observed and recorded, and then the test medium was immediately washed off with clean water and dried with filter paper.
[0122] Place the test piece in a container of petroleum ether or acetone with a boiling range of 60-90℃. Remove the oil from the surface of the test piece with degreased cotton, then soak it in anhydrous ethanol for 5 minutes for further degreasing and dehydration. Remove the test piece and soak it in the acid cleaning solution prepared according to Appendix A (the standard appendix) for 5 minutes, while gently wiping the corrosion products on the surface of the test piece with a small amount of degreased cotton using tweezers. Remove the test piece from the cleaning solution, rinse off the residual acid with tap water, and immediately immerse the test piece in a sodium hydroxide solution (60 g / L) for 30 seconds, then rinse with tap water, and then soak it in anhydrous ethanol for about 5 minutes, washing and dehydrating twice. Remove the test piece, place it on filter paper, and dry it with cold air. Then wrap the test piece with filter paper, store it in a desiccator, and weigh it after 1 hour, accurate to 0.1 mg. Observe and record the corrosion condition of the test piece surface. Calculate the corrosion rate and corrosion inhibition rate according to Formula I and Formula II.
[0123] , Formula I;
[0124] , Formula II;
[0125] In Formula I, r corr The uniform corrosion rate is expressed in mm / year; m represents the mass of the specimen before the test, in g; m t S1 represents the mass of the test specimen after the test, in grams; S2 represents the total area of the test specimen, in centimeters. 2 ρ represents the density of the sample material, in g / cm³. 2 t represents the test time, h.
[0126] In Formula II, η1 represents the corrosion inhibition rate (%), Δm0 represents the mass loss of the test piece in the blank test (g), and Δm1 represents the mass loss of the test piece in the dosing test (g).
[0127] Table 1. Content of various components in simulated water
[0128]
[0129] 1.2 Test Results
[0130] The measurement results are shown in Table 2.
[0131] Table 2. Slow-release performance of the corrosion inhibitors prepared in Examples 4 to 10
[0132]
[0133] 1.3 Results Analysis
[0134] Referring to the measurement results in Table 2, the corrosion rate of the blank control group was 0.891, while the corrosion inhibitors of the present invention were all below 0.148. The corrosion rates of corrosion inhibitors 1-7 prepared in Examples 4-10 of the present invention were all lower than those of the blank control group. Furthermore, the corrosion inhibition rates of corrosion inhibitors 1-7 of the present invention were all greater than 80%.
[0135] It is evident that the corrosion inhibitor provided by this invention exhibits excellent resistance to carbon dioxide corrosion.
[0136] Experimental Example 2
[0137] 2.1 Experimental Design
[0138] The corrosion inhibitor 5 prepared in Example 8 was used as a sample, and its structural composition was determined using an infrared spectrometer.
[0139] 2.2 Test Results
[0140] The measurement results are as follows Figure 1 As shown.
[0141] 2.3 Results Analysis
[0142] See Figure 1 According to the test results, the corrosion inhibitor 5 provided by this invention, at 3419 cm⁻¹, -1 The peak at 2931 cm⁻¹ is attributed to the stretching vibration of the NH bond. -1 The peak at 1673 cm⁻¹ is attributed to the asymmetric vibration of CH₂. -1 The peak at 1602 cm⁻¹ is attributed to the stretching vibration of the C=O bond; -1 The peaks at 1359 cm⁻¹ are attributed to the stretching vibrations of the C=N bonds. -1 The peaks at 1280 and 989 cm⁻¹ belong to the bending vibration of the CH₂ bond. -1 The peaks at 700 cm⁻¹ belong to the absorption peaks of the CH bending vibration of the naphthalene ring and the absorption peaks of the SS bond, respectively; -1 The peak at that point is attributed to the out-of-plane bending vibration of the monosubstituted CH ring.
[0143] visible, Figure 1 Infrared results show that the corrosion inhibitor provided by the present invention matches the chemical structure of the expected target product.
[0144] In conclusion, according to the determination of Test Example 1 and Test Example 2, the corrosion inhibitor provided by the present application has a stable chemical structure and excellent carbon dioxide corrosion resistance. It can be seen that the imidazoline ring in the corrosion inhibitor can enable the corrosion inhibitor to be adsorbed on the surface of steel; the s-s ring present enhances the hydrophobicity of the corrosion inhibitor, and the introduction of S further enhances the adsorption capacity of the corrosion inhibitor molecules; the simultaneous presence of the naphthalene ring further enhances the hydrophobicity of the corrosion inhibitor molecules, increases the coverage area of the corrosion inhibitor, and further enhances the corrosion inhibition performance of the corrosion inhibitor; and the modification of the benzyl chloride monomer enhances the water solubility, film-forming property and corrosion inhibition performance of the corrosion inhibitor, and further achieves the purpose of slowing down corrosion.
[0145] As can be seen from the above examples, the present application provides a corrosion inhibitor against carbon dioxide corrosion and a preparation method and application thereof, and the corrosion inhibitor has the advantages of good corrosion inhibition effect, stable structure and the like, and the corrosion inhibition rate is greater than 80%.
[0146] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of protection of the present application.
Claims
1. A method for preparing a corrosion inhibitor, characterized in that, Includes the following steps: S1. Take raw materials according to the molar ratio of α-lipoic acid, diethylenetriamine, formaldehyde, 2-naphthyl ethyl ketone, and benzyl chloride of 1.0~1.2:0.8~1.2:1.2~2.0:1.0~1.4:1.0~1.
4. Mix α-lipoic acid and diethylenetriamine and react at 140~160℃ for 2~5h, and then react at 190~210℃ for 2~5h to obtain the first product. S2. Formaldehyde, 2-naphthyl ethyl ketone and the first product are mixed in ethanol as solvent. The reaction temperature is 60~90℃ and the reaction time is 3~8h to obtain the second product. S3. Mix benzyl chloride and the second product, react at 90~110℃ for 2~6 hours to obtain the finished corrosion inhibitor.
2. The method for preparing the corrosion inhibitor according to claim 1, characterized in that, In step S1, xylene is used as a water-carrying agent and the reaction is carried out in a nitrogen atmosphere.
3. The method for preparing the corrosion inhibitor according to claim 2, characterized in that, Step S3 further includes vacuum drying after the reaction.
4. The method for preparing the corrosion inhibitor according to claim 3, characterized in that, The vacuum drying process is carried out at a temperature of 70-90°C for 0.5-1 hour.
5. A corrosion inhibitor for resisting carbon dioxide corrosion, prepared by the method of any one of claims 1-4.
6. The application of the corrosion inhibitor as described in claim 5 in preventing carbon dioxide corrosion.