Preparation method of modified imidazoline corrosion inhibitor

Abstract

The invention relates to the technical field of corrosion inhibitors, and discloses a preparation method of a modified imidazoline corrosion inhibitor, which comprises the following steps: carrying out quaternization reaction on tertiary amine group in an imidazoline intermediate and chlorine in benzyl chloride to generate quaternary ammonium salt, introducing hydroxyl, and continuing to carry out esterification reaction with boric acid group in 4-aminophenylboronic acid to obtain the modified imidazoline corrosion inhibitor. The modified imidazoline corrosion inhibitor is prepared by the following steps of: firstly, introducing amino groups, then carrying out amidation reaction with acyl chloride groups in 4-vinyl benzoyl chloride, introducing alkenyl groups, and finally carrying out click reaction with sulfydryl groups in DSB-TA, so as to generate the modified imidazoline corrosion inhibitor. The modified imidazoline corrosion inhibitor disclosed by the invention has a relatively good corrosion inhibition effect.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion inhibitors, and specifically to a preparation method of a modified imidazoline-based corrosion inhibitor. Background Art

[0002] Imidazoline-based corrosion inhibitors are widely used in industries such as petroleum, chemical engineering, and electric power due to their good corrosion inhibition performance and environmental friendliness. However, the corrosion inhibition effect of traditional imidazoline-based corrosion inhibitors is limited and difficult to meet the requirements of modern industries. Therefore, how to avoid this phenomenon is the key to solving the problem. The Chinese invention patent application with the publication number CN1110093609B discloses a method for improving the antifreeze property of an unsaturated higher fatty acid imidazoline corrosion inhibitor. The antifreeze property of this corrosion inhibitor is improved, and there is no precipitation or stratification phenomenon at a lower ambient temperature. However, its temperature application range is relatively narrow. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a preparation method of a modified imidazoline-based corrosion inhibitor, which has a good corrosion inhibition effect.

[0004] To achieve the above object, the present invention provides the following technical solutions: A preparation method of a modified imidazoline-based corrosion inhibitor, the preparation method of the modified imidazoline-based corrosion inhibitor includes the following steps:

[0005] S1. Add an imidazoline intermediate to an N,N-dimethylformamide solvent, heat it, then add benzyl chloride to it, keep the temperature unchanged, stir and react, perform rotary evaporation, and wash to obtain quaternary ammonium imidazoline;

[0006] S2. Add the quaternary ammonium imidazoline and 4-aminophenylboronic acid to 25-35 mL of an N,N-dimethylformamide solvent, stir and mix, continue to add anhydrous magnesium sulfate, stir and react at 80-90 °C, after completion, perform reduced pressure distillation, wash and dry to obtain amino-boron-containing imidazoline;

[0007] S3. Add the amino-boron-containing imidazoline and a pyridine catalyst to 36-45 mL of an N,N-dimethylformamide solvent, stir and dissolve, then continue to add 4-vinylbenzoyl chloride, react at 70-80 °C for 3-5 h, after completion, concentrate the solution, wash to obtain alkenyl-boron-containing imidazoline;

[0008] S4. Add the alkenyl-boron-containing imidazoline to 20-40 mL of an N,N-dimethylformamide solvent, stir and disperse, then add DSB-TA and a benzoin dimethyl ether photoinitiator, irradiate with ultraviolet light of 365 nm at 25-40 °C for 2-4 h, after completion, perform centrifugal separation, wash and dry to obtain a modified imidazoline-based corrosion inhibitor.

[0009] Further, the heating temperature in S1 is 100-105 °C.

[0010] Further, the stirring reaction time in S1 is 3 - 4h.

[0011] Further, the dosage ratio of N,N - dimethylformamide, imidazoline intermediate, and benzyl chloride in S1 is 30 - 35 mL: 4.61 - 5.3 g: 5 - 5.62 g.

[0012] Further, the mass ratio of quaternary ammonium imidazoline, 4 - aminophenylboronic acid, and anhydrous magnesium sulfate in S2 is 4.27 - 4.45 g: 3 - 3.6 g: 0.02 - 0.04 g.

[0013] Further, the stirring reaction time in S2 is 4 - 6h.

[0014] Further, the mass ratio of amino - containing boron imidazoline, pyridine catalyst, and 4 - vinylbenzoyl chloride in S3 is 2.25 - 2.6 g: 0.012 - 0.03 g: 2.1 - 2.44 g.

[0015] Further, the mass ratio of alkenyl - containing boron imidazoline, DSB - TA, and benzoin dimethyl ether photoinitiator in S4 is 2.31 - 2.4 g: 1.1 - 1.34 g: 0.02 - 0.03 g.

[0016] Beneficial technical effects

[0017] In the present invention, the quaternary ammonium reaction is carried out between the tertiary amino group in the imidazoline intermediate and the chlorine in benzyl chloride to generate a quaternary ammonium salt, and at the same time, a hydroxyl group is introduced. Then, an esterification reaction is carried out with the boric acid group in 4 - aminophenylboronic acid to introduce an amino group. Then, an amidation reaction occurs with the acyl chloride group in 4 - vinylbenzoyl chloride to introduce an alkenyl group. Finally, a click reaction occurs with the mercapto group in DSB - TA to generate a modified imidazoline - type corrosion inhibitor. The quaternary ammonium salt group in the modified imidazoline - type corrosion inhibitor can form a protective film on the metal surface, change the metal surface state and the double - layer structure, increase the activation energy of the corrosion reaction, and thus reduce the metal corrosion rate; the boron element forms a protective oxide film or adsorption film on the metal surface to inhibit the corrosion process; the modified imidazoline - type corrosion inhibitor has a longer molecular chain, increasing the hydrophobicity of the film, and the multiple S, N, O electron - donating groups contained therein form a tighter adsorption film, achieving a better corrosion inhibition effect; the click reaction between the alkenyl group in the alkenyl - containing boron imidazoline and the mercapto group in DSB - TA improves the substitution degree of its imidazoline group, making its corrosion inhibition effect better. Specific embodiments

[0018] Preparation method of DSB-TA: Refer to the literature "Study on the Corrosion Inhibition Performance of Amino Acid and Peptide Bis-Schiff Base Corrosion Inhibitors on Q235 Steel". Add 20 mmol of glutathione, 40 mmol of sodium hydroxide and 50 mL of absolute ethanol to a 250 mL three-necked flask in sequence and mix evenly. Under the condition of a warm water bath, dropwise add 10 mmol of terephthalic acid dissolved in 100 mL of ethanol and stir continuously. Stop heating after no more solids are added to the reaction solution. Transfer the obtained mixed solution to a beaker and let it cool naturally. Filter by suction and wash repeatedly with absolute ethanol for multiple times. Cool and air-dry at room temperature and grind. 2,2'-((1,4-Phenylenebis(formylmethylene))bis(aza-ylmethylene))bis(5-((1((carboxymethyl)amino)-3-mercapto-1-oxopropan-2-yl)amino)-5-oxopentanoic acid) (DSB-TA) can be obtained. The structural formula is as follows:

[0019]

[0020] Preparation of imidazoline intermediate: Refer to the literature "Synthesis and Performance Study of Compound Corrosion Inhibitors for H2S / CO2 Gathering and Transportation Pipelines". Add 100.2 - 100.6 g of lauric acid to a 1000 mL four-necked flask, add 48 - 50 g of N,N-dimethylformamide, dropwise add 62 - 62.4 g of N-(2-hydroxyethyl)ethylenediamine under stirring, then add 40 - 41 g of xylene and 4.8 - 5 g of boric acid catalyst, stir and heat to 110 - 120 °C, reflux for 2 - 2.5 h for dehydration amidation reaction. After the amidation reaction is completed, connect a circulating water pump to evacuate, continue to heat up to 160 °C for 2 h, 200 °C for 2 h, 220 °C for 2 h to complete the cyclization reaction. After the reaction is completed, cool down. The obtained colloidal solid is washed with acetone, filtered and dried to obtain the imidazoline intermediate.

[0021] Example 1

[0022] S1. Add 4.61 g of imidazoline intermediate to 30 mL of N,N-dimethylformamide solvent, heat to 100 °C, then add 5 g of benzyl chloride to it, keep the temperature unchanged and stir for 3 h to obtain quaternized imidazoline;

[0023] S2. Add 4.27 g of quaternized imidazoline and 3 g of 4-aminophenylboronic acid to 25 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.02 g of anhydrous magnesium sulfate, stir and react at 80 °C for 4 h. After completion, carry out vacuum distillation, wash and dry to obtain amino-functionalized boron-containing imidazoline;

[0024] S3. Add 2.25 g of boron-containing aminoimidazoline and 0.012 g of pyridine catalyst to 36 mL of N,N-dimethylformamide solvent. After stirring and dissolving, continue to add 2.1 g of 4-vinylbenzoyl chloride, and react at 70 °C for 3 h. After completion, concentrate the solution, wash it, and obtain vinylated boron-containing imidazoline;

[0025] S4. Add 2.31 g of vinylated boron-containing imidazoline to 20 mL of N,N-dimethylformamide solvent, stir and disperse it, then add 1.1 g of DSB-TA and 0.02 g of benzoin dimethyl ether photoinitiator. Under ultraviolet light irradiation at 365 nm at 25 °C for 2 h, after completion, centrifuge, wash, and dry to obtain a modified imidazoline corrosion inhibitor.

[0026] Example 2

[0027] S1. Add 5.3 g of imidazoline intermediate to 35 mL of N,N-dimethylformamide solvent, heat to 105 °C, then add 5.62 g of benzyl chloride to it, keep the temperature unchanged, and stir and react for 4 h to obtain quaternized imidazoline;

[0028] S2. Add 4.45 g of quaternized imidazoline and 3.6 g of 4-aminophenylboronic acid to 35 mL of N,N-dimethylformamide solvent, stir and mix, continue to add 0.04 g of anhydrous magnesium sulfate, and stir and react at 90 °C for 6 h. After completion, carry out vacuum distillation, wash, and dry to obtain boron-containing aminoimidazoline;

[0029] S3. Add 2.6 g of boron-containing aminoimidazoline and 0.03 g of pyridine catalyst to 45 mL of N,N-dimethylformamide solvent. After stirring and dissolving, continue to add 2.44 g of 4-vinylbenzoyl chloride, and react at 80 °C for 5 h. After completion, concentrate the solution, wash it, and obtain vinylated boron-containing imidazoline;

[0030] S4. Add 2.4 g of vinylated boron-containing imidazoline to 40 mL of N,N-dimethylformamide solvent, stir and disperse it, then add 1.34 g of DSB-TA and 0.03 g of benzoin dimethyl ether photoinitiator. Under ultraviolet light irradiation at 365 nm at 40 °C for 4 h, after completion, centrifuge, wash, and dry to obtain a modified imidazoline corrosion inhibitor.

[0031] Example 3

[0032] S1. Add 4.82 g of imidazoline intermediate to 32 mL of N,N-dimethylformamide solvent, heat to 103 °C, then add 5.61 g of benzyl chloride to it, keep the temperature unchanged, and stir and react for 3.5 h to obtain quaternized imidazoline;

[0033] S2. Add 4.36 g of quaternized imidazoline and 3.3 g of 4-aminophenylboronic acid to 30 mL of N,N-dimethylformamide solvent, stir and mix, then continue to add 0.03 g of anhydrous magnesium sulfate, stir and react at 85 °C for 5 h. After completion, perform vacuum distillation, wash and dry to obtain amino-functionalized boron-containing imidazoline;

[0034] S3. Add 2.47 g of amino-functionalized boron-containing imidazoline and 0.018 g of pyridine catalyst to 40 mL of N,N-dimethylformamide solvent. After stirring and dissolving, continue to add 2.34 g of 4-vinylbenzoyl chloride and react at 75 °C for 4 h. After completion, concentrate the solution, wash to obtain vinyl-functionalized boron-containing imidazoline;

[0035] S4. Add 2.35 g of vinyl-functionalized boron-containing imidazoline to 30 mL of N,N-dimethylformamide solvent, stir and disperse, then add 1.25 g of DSB-TA and 0.025 g of benzoin dimethyl ether photoinitiator thereto. Under ultraviolet light irradiation at 365 nm at 30 °C for 3 h. After completion, perform centrifugal separation, wash and dry to obtain the modified imidazoline corrosion inhibitor.

[0036] Example 4

[0037] S1. Add 4.61 g of imidazoline intermediate to 30 mL of N,N-dimethylformamide solvent, heat to 100 °C, then add 5 g of benzyl chloride thereto, keep the temperature unchanged, stir and react for 3 h to obtain quaternized imidazoline;

[0038] S2. Add 4.45 g of quaternized imidazoline and 3.6 g of 4-aminophenylboronic acid to 35 mL of N,N-dimethylformamide solvent, stir and mix, then continue to add 0.04 g of anhydrous magnesium sulfate, stir and react at 90 °C for 6 h. After completion, perform vacuum distillation, wash and dry to obtain amino-functionalized boron-containing imidazoline;

[0039] S3. Add 2.6 g of amino-functionalized boron-containing imidazoline and 0.03 g of pyridine catalyst to 45 mL of N,N-dimethylformamide solvent. After stirring and dissolving, continue to add 2.44 g of 4-vinylbenzoyl chloride and react at 80 °C for 5 h. After completion, concentrate the solution, wash to obtain vinyl-functionalized boron-containing imidazoline;

[0040] S4. Add 2.35 g of vinyl-functionalized boron-containing imidazoline to 30 mL of N,N-dimethylformamide solvent, stir and disperse, then add 1.25 g of DSB-TA and 0.025 g of benzoin dimethyl ether photoinitiator thereto. Under ultraviolet light irradiation at 365 nm at 30 °C for 3 h. After completion, perform centrifugal separation, wash and dry to obtain the modified imidazoline corrosion inhibitor.

[0041] Example 5

[0042] S1. Add 5.3 g of imidazoline intermediate to 35 mL of N,N-dimethylformamide solvent, heat to 105 °C, then add 5.62 g of benzyl chloride to it, keep the temperature unchanged, and stir and react for 4 h to obtain quaternized imidazoline;

[0043] S2. Add 4.36 g of quaternized imidazoline and 3.3 g of 4-aminophenylboronic acid to 30 mL of N,N-dimethylformamide solvent, stir and mix, then continue to add 0.03 g of anhydrous magnesium sulfate, stir and react at 85 °C for 5 h. After completion, carry out vacuum distillation, wash and dry to obtain boron-containing imidazoline with amino group;

[0044] S3. Add 2.47 g of boron-containing imidazoline with amino group and 0.018 g of pyridine catalyst to 40 mL of N,N-dimethylformamide solvent, stir and dissolve, then continue to add 2.34 g of 4-vinylbenzoyl chloride, react at 75 °C for 4 h. After completion, concentrate the solution, wash to obtain boron-containing imidazoline with alkenyl group;

[0045] S4. Add 2.31 g of boron-containing imidazoline with alkenyl group to 20 mL of N,N-dimethylformamide solvent, stir and disperse, then add 1.1 g of DSB-TA and 0.02 g of benzoin dimethyl ether photoinitiator to it. Under 25 °C, irradiate with ultraviolet light of 365 nm for 2 h. After completion, carry out centrifugal separation, wash and dry to obtain modified imidazoline corrosion inhibitor.

[0046] Example 6

[0047] S1. Add 4.82 g of imidazoline intermediate to 32 mL of N,N-dimethylformamide solvent, heat to 103 °C, then add 5.61 g of benzyl chloride to it, keep the temperature unchanged, and stir and react for 3.5 h to obtain quaternized imidazoline;

[0048] S2. Add 4.27 g of quaternized imidazoline and 3 g of 4-aminophenylboronic acid to 25 mL of N,N-dimethylformamide solvent, stir and mix, then continue to add 0.02 g of anhydrous magnesium sulfate, stir and react at 80 °C for 4 h. After completion, carry out vacuum distillation, wash and dry to obtain boron-containing imidazoline with amino group;

[0049] S3. Add 2.25 g of boron-containing imidazoline with amino group and 0.012 g of pyridine catalyst to 36 mL of N,N-dimethylformamide solvent, stir and dissolve, then continue to add 2.1 g of 4-vinylbenzoyl chloride, react at 70 °C for 3 h. After completion, concentrate the solution, wash to obtain boron-containing imidazoline with alkenyl group;

[0050] S4. Add 2.4 g of boron-containing imidazoline with alkenyl group to 40 mL of N,N-dimethylformamide solvent, stir and disperse it, then add 1.34 g of DSB-TA and 0.03 g of benzoin dimethyl ether photoinitiator thereto. Under ultraviolet light irradiation at 365 nm for 4 h at 40 °C, after completion, centrifuge, wash and dry to obtain the modified imidazoline corrosion inhibitor.

[0051] Comparative Example 1

[0052] Compared with Example 6, the difference in this comparative example is that an imidazoline intermediate is used instead of the modified imidazoline corrosion inhibitor.

[0053] Comparative Example 2

[0054] Compared with Example 6, the difference in this comparative example is that quaternized imidazoline is used instead of the modified imidazoline corrosion inhibitor.

[0055] Performance Test

[0056] According to the methods and evaluation indexes for measuring the atmospheric static corrosion rate and corrosion inhibition rate in the petroleum industry standard SY / T5405-2019 "Test Methods and Evaluation Indexes for the Performance of Corrosion Inhibitors for Acidizing", measure the corrosion rate and corrosion inhibition rate of the modified imidazoline corrosion inhibitor of the present invention; refer to the test conditions for the methods and evaluation indexes for measuring the atmospheric static corrosion rate and corrosion inhibition rate: steel sheet material: Q235, evaluation temperature: 90 °C, evaluation time: 4 h, the dosage of the corrosion inhibitor is 0.1% of the volume of the acid solution, and the acid solution is 5 wt% hydrochloric acid.

[0057] Table 1: Corrosion Inhibition Performance Test.

[0058]

[0059]

[0060] As can be seen from Table 1, for the modified imidazoline corrosion inhibitor of the present invention, Examples 1-6 have better corrosion inhibition effects compared with Comparative Examples 1-2.

[0061] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. A preparation method of a modified imidazoline corrosion inhibitor, characterized in that, The preparation method of the modified imidazoline corrosion inhibitor comprises the following steps: S1. Add the imidazoline intermediate to the N,N-dimethylformamide solvent, heat it, then add benzyl chloride to it, keep the temperature unchanged, stir and react to obtain quaternary ammonium imidazoline; S2. Add the quaternary ammonium imidazoline and 4-aminophenylboronic acid to 25 - 35 mL of N,N-dimethylformamide solvent, stir and mix, then continue to add anhydrous magnesium sulfate, stir and react at 80 - 90 °C, after completion, carry out vacuum distillation, wash and dry to obtain amino-containing boron imidazoline; S3. Add the amino-containing boron imidazoline and pyridine catalyst to 36 - 45 mL of N,N-dimethylformamide solvent, stir and dissolve, then continue to add 4-vinylbenzoyl chloride, react at 70 - 80 °C for 3 - 5 h, after completion, concentrate the solution, wash to obtain alkenyl-containing boron imidazoline; S4. Add the alkenyl-containing boron imidazoline to 20 - 40 mL of N,N-dimethylformamide solvent, stir and disperse, then add DSB-TA and benzoin dimethyl ether photoinitiator to it, irradiate with ultraviolet light of 365 nm at 25 - 40 °C for 2 - 4 h, after completion, carry out centrifugal separation, wash and dry to obtain the modified imidazoline corrosion inhibitor.

2. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that The heating temperature in S1 is 100 - 105 °C.

3. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The stirring reaction time in S1 is 3 - 4 h.

4. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The dosage ratio of N,N-dimethylformamide, imidazoline intermediate and benzyl chloride in S1 is 30 - 35 mL:4.61 - 5.3 g:5 - 5.62 g.

5. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The mass ratio of quaternary ammonium imidazoline, 4-aminophenylboronic acid and anhydrous magnesium sulfate in S2 is 4.27 - 4.45 g:3 - 3.6 g:0.02 - 0.04 g.

6. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The stirring reaction time in S2 is 4 - 6 h.

7. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The mass ratio of amino-containing boron imidazoline, pyridine catalyst and 4-vinylbenzoyl chloride in S3 is 2.25 - 2.6 g:0.012 - 0.03 g:2.1 - 2.44 g.

8. The preparation method of the modified imidazoline corrosion inhibitor according to claim 1, characterized in that, The mass ratio of alkenyl-containing boron imidazoline, DSB-TA and benzoin dimethyl ether photoinitiator in S4 is 2.31 - 2.4 g:1.1 - 1.34 g:0.02 - 0.03 g.

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