A gemini imidazoline quaternary ammonium salt corrosion inhibitor and a preparation method thereof

Abstract

The application relates to the technical field of corrosion inhibitors, and discloses a gemini imidazoline quaternary ammonium salt corrosion inhibitor and a preparation method thereof. The gemini imidazoline quaternary ammonium salt corrosion inhibitor comprises the following components in mass fraction: 25-35 parts of gemini imidazoline quaternary ammonium salt, 5-15 parts of a thiourea compound, 3-7 parts of a fatty alcohol polyoxyethylene ether and 50-60 parts of a solvent; the preparation method of the gemini imidazoline quaternary ammonium salt corrosion inhibitor comprises the following steps: uniformly mixing the components to obtain the gemini imidazoline quaternary ammonium salt corrosion inhibitor. Through the technical scheme, the problem of poor corrosion inhibition effect of the gemini imidazoline quaternary ammonium salt corrosion inhibitor in the prior art is solved.

Description

Technical Field

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

[0002] Corrosion inhibitors are created by adding special active substances that adsorb onto the metal surface, passivating the surface and thus slowing down or inhibiting the corrosion process. Adding even trace amounts of corrosion inhibitors can significantly suppress or reduce the metal corrosion rate. Corrosion inhibitors not only protect metals in corrosive environments but also serve as additives to control the chemical or electrochemical processing properties of metal surfaces, demonstrating a variety of applications.

[0003] Gemini surfactants are a new generation of surfactants that link two traditional mono-headed monoalkane chains together at the ionic head group using a linking group via chemical bonds. They possess high surface activity, low critical surface micelle concentration, low Krafft point, and good foam stability, calcium soap dispersion properties, wetting properties, solubilizing and detergency. Among them, gemini imidazoline quaternary ammonium salts have environmental and economic advantages and are widely used liquid corrosion inhibitors in oilfield production systems, but their corrosion inhibition effect is generally limited. Summary of the Invention

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

[0005] The technical solution of the present invention is as follows:

[0006] A gemini-imidazoline quaternary ammonium salt corrosion inhibitor comprises the following components in parts by weight: 25-35 parts gemini-imidazoline quaternary ammonium salt, 5-15 parts thiourea compound, 3-7 parts fatty alcohol polyoxyethylene ether, and 50-60 parts solvent.

[0007] As a further technical solution, the mass ratio of the gemini imidazoline quaternary ammonium salt to the thiourea compound is 7:3 to 4:1.

[0008] The inventors discovered that when the mass ratio of gemini-imidazoline quaternary ammonium salt to thiourea compounds is 7:3 to 4:1, the resulting gemini-imidazoline quaternary ammonium salt corrosion inhibitor exhibits better slow-release effect.

[0009] As a further technical solution, the mass ratio of the gemini imidazoline quaternary ammonium salt to the thiourea compound is 3:1.

[0010] As a further technical solution, the thiourea compound includes one or more of dithiourea, N,N'-di-o-tolylthiourea, and butylthiourea.

[0011] As a further technical solution, the thiourea compounds include N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 2:8 to 4:6.

[0012] As a further technical solution, the thiourea compound includes N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 3:7.

[0013] As a further technical solution, the solvent is dimethylformamide.

[0014] The present invention also proposes a method for preparing a gemini-imidazoline quaternary ammonium salt corrosion inhibitor, comprising the following steps: mixing the components in the specified mass fractions evenly to obtain the gemini-imidazoline quaternary ammonium salt corrosion inhibitor.

[0015] As a further technical solution, the mixing temperature is 45~55℃.

[0016] As a further technical solution, the mixing time is 50~100min.

[0017] The working principle and beneficial effects of this invention are as follows:

[0018] 1. This invention adds thiourea compounds to a combination of gemini imidazoline quaternary ammonium salts as a corrosion inhibitor, which improves the corrosion inhibition effect of gemini imidazoline quaternary ammonium salt corrosion inhibitors and solves the problem of poor corrosion inhibition effect of gemini imidazoline quaternary ammonium salt corrosion inhibitors in the prior art. The gemini imidazoline quaternary ammonium salt corrosion inhibitor provided by this invention not only has a good corrosion inhibition effect, but is also environmentally friendly and economical, and meets market demands.

[0019] 2. This invention limits the thiourea compounds to N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 2:8 to 4:6, which further improves the corrosion inhibition effect of the gemini imidazoline quaternary ammonium salt corrosion inhibitor. Detailed Implementation

[0020] 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.

[0021] In the following examples and comparative examples, the gemini imidazoline quaternary ammonium salts were all prepared by the following methods:

[0022] 34.79 g of oleic acid, 15.28 g of diethylenetriamine, and 0.2 g of alumina catalyst were added to a three-necked flask, followed by 40 mL of xylene. The mixture was dehydrated by gradient heating at 140 °C, 170 °C, and 220 °C. The mixture was then cooled to 140 °C and distilled under reduced pressure to generate an amide, which was then cyclized to obtain an imidazoline intermediate. The imidazoline intermediate and benzyl chloride were added to the three-necked flask at a molar ratio of 1:1. The mixture was stirred and heated to 100 °C for 4 h. 8 mL of 1,4-dibromobutane was then added, and the reaction was continued at 80 °C for another 8 h. After filtration, the mixture was recrystallized five times with acetone / ethyl acetate, filtered again, and dried under vacuum at 50 °C for 48 h to obtain the gemini imidazoline quaternary ammonium salt.

[0023] Example 1

[0024] Add 35 parts of Gemini imidazoline quaternary ammonium salt, 5 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0025] Example 2

[0026] Add 32 parts of Gemini imidazoline quaternary ammonium salt, 8 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0027] Example 3

[0028] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 10 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0029] Example 4

[0030] Add 28 parts of Gemini imidazoline quaternary ammonium salt, 12 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0031] Example 5

[0032] Add 25 parts of Gemini imidazoline quaternary ammonium salt, 15 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0033] Example 6

[0034] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 10 parts of N,N'-di-o-tolylthiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0035] Example 7

[0036] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 10 parts of butyl thiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0037] Example 8

[0038] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 2 parts of N,N'-di-o-tolyl thiourea, 8 parts of butyl thiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0039] Example 9

[0040] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 3 parts of N,N'-di-o-tolyl thiourea, 7 parts of butyl thiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0041] Example 10

[0042] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 4 parts of N,N'-di-o-tolyl thiourea, 6 parts of butyl thiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0043] Example 11

[0044] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 4 parts of dithiourea, 6 parts of butyl thiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0045] Example 12

[0046] Add 30 parts of Gemini imidazoline quaternary ammonium salt, 4 parts of N,N'-di-o-tolylthiourea, 6 parts of dithiourea, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly to obtain Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0047] Comparative Example 1

[0048] Add 40 parts of Gemini imidazoline quaternary ammonium salt, 5 parts of AEO-9, and 55 parts of dimethylformamide to a reaction vessel and stir at 50°C for 80 minutes to mix evenly, thus obtaining Gemini imidazoline quaternary ammonium salt corrosion inhibitor.

[0049] Corrosion inhibition performance test:

[0050] Treatment group: After sanding the Q235 steel sheet (50mm×30mm×2mm) with sandpaper, clean it in sequence with distilled water and anhydrous ethanol, dry it, and weigh it as m0. Then, suspend the steel sheet in a 60℃ medium with 15wt% hydrochloric acid containing 250mg / L Gemini imidazoline quaternary ammonium salt corrosion inhibitor and soak it for 24 hours. Remove it, remove the corrosion products, clean it in sequence with distilled water and anhydrous ethanol, and dry it to constant weight as m1.

[0051] Blank group: The only difference from the treatment group is that the gemini imidazoline quaternary ammonium salt corrosion inhibitor is not added.

[0052] The corrosion rate and corrosion inhibition efficiency are calculated using the following formulas:

[0053] Corrosion rate = (m0 - m1) ÷ S ÷ t

[0054] m0: Mass of the steel sheet before corrosion, in grams;

[0055] m1: Mass of the steel sheet after corrosion, in grams;

[0056] S: Surface area of ​​the steel sheet, m² 2 ;

[0057] t: Immersion time of steel sheet, h;

[0058] Corrosion inhibition efficiency (%) = (Corrosion rate of blank group - Corrosion rate of treated group) ÷ Corrosion rate of blank group × 100;

[0059] The results are recorded in Table 1.

[0060] Table 1 Corrosion rate and corrosion inhibition efficiency

[0061]

[0062] As shown in Table 1, compared with Comparative Example 1, Examples 1-12 added thiourea compounds, while Comparative Example 1 did not add thiourea compounds. The corrosion inhibition efficiency of the gemini imidazoline quaternary ammonium salt corrosion inhibitors obtained in Examples 1-12 was higher than that in Comparative Example 1. This indicates that the addition of thiourea compounds and the use of gemini imidazoline quaternary ammonium salt in combination can improve the corrosion inhibition effect of gemini imidazoline quaternary ammonium salt corrosion inhibitors.

[0063] Compared with other examples, Examples 8-10 used N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 2:8 to 4:6. The corrosion inhibition efficiency of the gemini-imidazoline quaternary ammonium salt corrosion inhibitors obtained in Examples 8-10 was higher than that in other examples, indicating that using N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 2:8 to 4:6 can further improve the corrosion inhibition effect of the gemini-imidazoline quaternary ammonium salt corrosion inhibitors.

[0064] 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 gemini imidazoline quaternary ammonium salt corrosion inhibitor, characterized in that, The composition includes the following components in parts by weight: 25-35 parts of gemini imidazoline quaternary ammonium salt, 5-15 parts of thiourea compounds, 3-7 parts of fatty alcohol polyoxyethylene ether, and 50-60 parts of solvent; wherein the thiourea compounds include N,N'-di-o-tolyl thiourea and butyl thiourea in a mass ratio of 2:8 to 4:

6.

2. The gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 1, characterized in that, The mass ratio of the gemini imidazoline quaternary ammonium salt to the thiourea compound is 7:3 to 4:

1.

3. The gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 1, characterized in that, The mass ratio of the gemini imidazoline quaternary ammonium salt to the thiourea compound is 3:

1.

4. The gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 1, characterized in that, The thiourea compounds include N,N'-di-o-tolylthiourea and butylthiourea in a mass ratio of 3:

7.

5. The gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 1, characterized in that, The solvent is dimethylformamide.

6. A method for preparing a gemini imidazoline quaternary ammonium salt corrosion inhibitor according to any one of claims 1 to 5, characterized in that, Includes the following steps: The components in the specified mass fractions are mixed evenly to obtain a gemini imidazoline quaternary ammonium salt corrosion inhibitor.

7. The method for preparing a gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 6, characterized in that, The mixing temperature is 45~55℃.

8. The method for preparing a gemini imidazoline quaternary ammonium salt corrosion inhibitor according to claim 6, characterized in that, The mixing time is 50-100 minutes.

Images