A phosphorus ester modified imidazoline corrosion inhibitor and a preparation method thereof

Abstract

This invention relates to the field of corrosion inhibitor technology, and proposes a phosphoesterified modified imidazoline corrosion inhibitor and its preparation method. A phosphoesterified modified imidazoline corrosion inhibitor comprises the following components in parts by weight: 30-40 parts imidazoline, 20-30 parts alkyl phosphate, 10-20 parts polyvinylpyrrolidone iodine complex, and 50-70 parts water. This technical solution solves the problem of poor corrosion inhibition effect of existing imidazoline corrosion inhibitors.

Description

Technical Field

[0001] This invention relates to the field of corrosion inhibitor technology, specifically to a phosphoesterified modified imidazoline corrosion inhibitor and its preparation method. Background Technology

[0002] Corrosion inhibitors are made by adding special active substances that are adsorbed onto the metal surface, thus passivating the surface and slowing down the corrosion process. They can not only protect metals in corrosive environments, but also be used as additives to control the chemical or electrochemical processing properties of metal surfaces, and have multiple applications.

[0003] Corrosion inhibitors are broadly classified into inorganic and organic categories. Compared to inorganic inhibitors, organic inhibitors exhibit higher corrosion inhibition rates. Organic inhibitors are organic compounds containing functional groups such as nitrogen, oxygen, sulfur, or triple bonds, including amines, aldehydes, alkynols, heterocyclic compounds, imidazolines, and organosulfur compounds. Among these, imidazoline inhibitors are currently the most widely used, but their corrosion inhibition effect still needs further improvement. Summary of the Invention

[0004] This invention proposes a phosphoesterified modified imidazoline corrosion inhibitor and its preparation method, which solves the problem of poor corrosion inhibition effect of imidazoline corrosion inhibitors in related technologies.

[0005] The technical solution of the present invention is as follows: A phosphoesterified modified imidazoline corrosion inhibitor comprises the following components in parts by weight: 30-40 parts imidazoline, 20-30 parts alkyl phosphate, 10-20 parts polyvinylpyrrolidone iodine complex, and 50-70 parts water.

[0006] As a further technical solution, the mass ratio of the imidazoline to the polyvinylpyrrolidone iodine complex is 35:13~17.

[0007] As a further technical solution, the mass content of available iodine in the polyvinylpyrrolidone iodine complex is 10-11%.

[0008] As a further technical solution, the effective iodine content in the polyvinylpyrrolidone iodine complex is 10.5%.

[0009] As a further technical solution, the imidazoline is an acetic acid-modified imidazoline.

[0010] As a further technical solution, the preparation method of the acetic acid modified imidazoline includes the following steps: S1. Using oleic acid and diethylenetriamine as reactants, a reaction is carried out to obtain an imidazoline intermediate; S2. The imidazoline intermediate is mixed with acetic acid and reacted to obtain acetic acid-modified imidazoline.

[0011] As a further technical solution, the reaction temperature in S1 is 170~190℃, and the reaction time is 4~6h.

[0012] As a further technical solution, the reaction temperature in S2 is 110~130℃, and the reaction time is 1~3h.

[0013] As a further technical solution, the method for preparing the alkyl phosphate ester includes the following steps: mixing polyoxyethylene alkylphenol ether, phosphorus pentoxide and water, and then reacting them to obtain the alkyl phosphate ester.

[0014] As a further technical solution, the reaction temperature is 70~80℃ and the reaction time is 5~6h.

[0015] The present invention also proposes a method for preparing a phosphoesterified modified imidazoline corrosion inhibitor, wherein the components in the specified mass fractions are mixed evenly to obtain the phosphoesterified modified imidazoline corrosion inhibitor.

[0016] The working principle and beneficial effects of this invention are as follows: 1. This invention utilizes a combination of imidazoline and alkyl phosphate esters to provide a phosphoester-modified imidazoline corrosion inhibitor with excellent corrosion inhibition effect. After physical modification of imidazoline by alkyl phosphate esters, imidazoline can form an adsorption film on the metal surface to inhibit corrosion, while alkyl phosphate esters can form a precipitation film on the metal surface to inhibit corrosion. The combined use of these two agents enhances the film strength, thus improving the corrosion inhibition effect. Furthermore, the addition of polyvinylpyrrolidone iodine complex ensures the integrity and tightness of the film, further improving the corrosion inhibition effect.

[0017] 2. The present invention limits the mass ratio of imidazoline to polyvinylpyrrolidone iodine complex to 35:13~17, which further improves the corrosion inhibition effect of the corrosion inhibitor. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 10 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0020] Example 2 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 170℃ and react for 6 hours. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 110℃ for 3 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.075 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 70°C and react for 6 hours, then lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester. S4. Mix 30 parts of acetic acid-modified imidazoline, 20 parts of alkyl phosphate, 10 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10wt%), and 50 parts of water evenly to obtain a corrosion inhibitor.

[0021] Example 3 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 190℃ and react for 4 hours. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 130℃ for 1 h to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 10 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.075 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 80°C and react for 5 hours, then lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester. S4. Mix 40 parts of acetic acid-modified imidazoline, 30 parts of alkyl phosphate, 10 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10wt%), and 70 parts of water evenly to obtain a corrosion inhibitor.

[0022] Example 4 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 13 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0023] Example 5 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 15 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0024] Example 6 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 17 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0025] Example 7 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 20 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0026] Example 8 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 15 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 10.5 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0027] Example 9 S1. Add 43g of oleic acid and 16.5g of diethylenetriamine to a 250mL three-necked flask, add 30mL of xylene, heat with a heating mantle, and start reflux when the temperature reaches 140℃. Water will be released. Increase the temperature to 180℃ and react for 5h. When the volume of water separated reaches the theoretical water production value, stop the reaction, evaporate the remaining solvent under reduced pressure, and dry under vacuum to obtain the imidazoline intermediate. S2. The imidazoline intermediate was reacted with acetic acid at an equimolar ratio at 120℃ for 2 hours to obtain acetic acid modified imidazoline. S3. Add 0.1 mol of polyoxyethylene alkylphenol ether (the polyoxyethylene alkylphenol ether has 4 oxyethylene groups and 8 alkyl carbon groups on the side chain of the benzene ring) to a three-necked flask, add 0.08 mol of distilled water and stir until homogeneous. Add 0.05 mol of phosphorus pentoxide solid powder within 1 hour under stirring at 40°C, raise the temperature to 75°C and react for 5.5 hours, lower the temperature to 60°C and add water for hydrolysis to obtain alkyl phosphate ester; S4. Mix 35 parts of acetic acid-modified imidazoline, 25 parts of alkyl phosphate, 15 parts of polyvinylpyrrolidone iodine complex (with an effective iodine content of 11 wt%), and 60 parts of water evenly to obtain a corrosion inhibitor.

[0028] Comparative Example 1 The only difference from Example 1 is that polyvinylpyrrolidone iodine complex is not added in S4.

[0029] The corrosion inhibitors obtained in Examples 1-9 and Comparative Example 1 were tested for uniform corrosion rate and corrosion inhibition rate according to the method in SY-T 5273-2000 "Performance Evaluation Method of Corrosion Inhibitors for Oilfield Produced Water". The test results are recorded in Table 1.

[0030] The experimental medium was artificially prepared simulated water: NaCl 30000 mg / L, MgCl2·6H2O 1000 mg / L, Na2SO4·10H2O 1000 mg / L, NaHCO3 1000 mg / L, CaCl2 1000 mg / L; The experimental specimen is rectangular, with dimensions of 50mm × 13mm × 1.5mm; Corrosion inhibitor dosage: 50 mg / L; Experimental temperature: 30℃; Experimental time: 72h.

[0031] Table 1 Uniform corrosion rate and corrosion inhibition rate

[0032] As can be seen from Table 1, the corrosion inhibitor provided by the present invention has a corrosion inhibition rate of over 94.1%, and has a good corrosion inhibition effect.

[0033] Compared with Comparative Example 1, Examples 1-9 added polyvinylpyrrolidone iodine complex, while Comparative Example 1 did not add polyvinylpyrrolidone iodine complex. The corrosion inhibition rate of the corrosion inhibitors obtained in Examples 1-9 was higher than that in Comparative Example 1, indicating that adding polyvinylpyrrolidone iodine complex can improve the corrosion inhibition effect of the corrosion inhibitor.

[0034] Compared with Examples 4-6, Examples 1 and 7 contain 10 parts of polyvinylpyrrolidone iodine complex, Examples 7 contain 20 parts of polyvinylpyrrolidone iodine complex, Examples 4 contain 13 parts of polyvinylpyrrolidone iodine complex, Examples 5 contain 15 parts of polyvinylpyrrolidone iodine complex, and Examples 6 contain 17 parts of polyvinylpyrrolidone iodine complex. The corrosion inhibition rate of the corrosion inhibitors obtained in Examples 4-6 is higher than that in Examples 1 and 7, indicating that when the mass ratio of imidazoline to polyvinylpyrrolidone iodine complex is 35:13-17, the corrosion inhibition effect of the corrosion inhibitor can be further improved.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A phosphoesterified modified imidazoline corrosion inhibitor, characterized in that, The product comprises the following components in parts by weight: 30-40 parts imidazoline, 20-30 parts alkyl phosphate, 10-20 parts polyvinylpyrrolidone iodine complex, and 50-70 parts water; the mass ratio of imidazoline to polyvinylpyrrolidone iodine complex is 35:13-17; the effective iodine content in the polyvinylpyrrolidone iodine complex is 10-11%; and the imidazoline is acetic acid modified imidazoline.

2. The phosphoesterified modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The method for preparing the acetic acid-modified imidazoline includes the following steps: S1. Using oleic acid and diethylenetriamine as reactants, a reaction is carried out to obtain an imidazoline intermediate; S2. The imidazoline intermediate is mixed with acetic acid and reacted to obtain acetic acid-modified imidazoline.

3. The phosphoesterified modified imidazoline corrosion inhibitor according to claim 2, characterized in that, The reaction temperature in S1 is 170~190℃, and the reaction time is 4~6h.

4. The phosphoesterified modified imidazoline corrosion inhibitor according to claim 2, characterized in that, The reaction temperature in S2 is 110~130℃, and the reaction time is 1~3h.

5. The phosphoesterified modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The method for preparing the alkyl phosphate ester includes the following steps: mixing polyoxyethylene alkylphenol ether, phosphorus pentoxide and water, and then reacting them to obtain the alkyl phosphate ester.

6. The phosphoesterified modified imidazoline corrosion inhibitor according to claim 5, characterized in that, The reaction temperature is 70~80℃, and the reaction time is 5~6h.

7. A method for preparing a phosphoesterified modified imidazoline corrosion inhibitor according to any one of claims 1 to 6, characterized in that, The components in the specified mass fractions are mixed evenly to obtain a phosphoesterified modified imidazoline corrosion inhibitor.

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