Heptadecyl imidazole efficient corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of corrosion inhibitors for steel in an acid environment, and particularly relates to a heptadecyl imidazole efficient corrosion inhibitor as well as a preparation method and application thereof. The heptadecyl imidazole high-efficiency corrosion inhibitor is methyl 3-(2-heptadecyl imidazole)-2-methyl propionate, and the chemical structural formula (I) of the heptadecyl imidazole high-efficiency corrosion inhibitor is as follows: # imgabs0. The invention also relates to a preparation method of the heptadecyl imidazole high-efficiency corrosion inhibitor. The heptadecyl imidazole efficient corrosion inhibitor is obtained through addition reaction of 2-heptadecyl imidazole and methyl methacrylate. The efficient corrosion inhibitor is low in dosage, the synthesis method is simple, and the product is efficient, safe and environmentally friendly; when being used as a steel corrosion inhibitor in acid environments such as industrial acid pickling and oil-gas well acidification, the corrosion inhibitor can obtain high corrosion inhibition efficiency with lower dosage compared with a conventional imidazole corrosion inhibitor; especially in a 1M HCl solution, when the dosage of the heptadecyl imidazole efficient corrosion inhibitor is 300mg / L, the corrosion inhibition efficiency on Q235 steel reaches 98.11%.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion inhibitors for steel in acidic environments, and specifically relates to a heptadecanediimidazole-based high-efficiency corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] Steel, as an indispensable and important material in industrial production and life, has a wide range of applications. However, during use, ordinary steel is corroded almost all the time; especially in industrial processes such as industrial pickling and oil and gas well acidizing, the acidic environment will cause serious corrosion of steel, which will lead to huge economic losses and waste of resources. In order to effectively prevent steel corrosion, a series of targeted measures can be taken, such as improving the corrosion resistance of materials, electrochemical protection, surface coating protection, the use of corrosion-resistant alloy materials, and the addition of corrosion inhibitors. Among these measures, corrosion inhibitors have become a widely used anti-corrosion method due to their excellent availability, high efficiency and ease of operation. However, improper use of corrosion inhibitors may cause a series of problems, such as pitting, hydrogen embrittlement and weightless corrosion on the surface of construction equipment, oil and gas well pipes, etc., and even cause sudden rupture of underground pipes in severe cases. Therefore, it is particularly important to select suitable corrosion inhibitors and apply them reasonably in practical projects such as industrial pickling and oil and gas well acidizing. Summary of the invention

[0003] The purpose of the present invention is to provide a heptadecyl imidazole-based efficient corrosion inhibitor and a preparation method and application thereof. The efficient corrosion inhibitor of the present invention has a low dosage, a simple synthesis method, and a highly efficient, safe, and environmentally friendly product. It is used as a steel corrosion inhibitor in acidic environments such as industrial pickling and oil and gas well acidizing. Compared with conventional imidazole corrosion inhibitors, a lower dosage can obtain a high corrosion inhibition efficiency.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] The present invention provides a heptadecyl imidazole type efficient corrosion inhibitor, wherein the heptadecyl imidazole type efficient corrosion inhibitor is methyl 3-(2-heptadecylimidazole)-2-methyl propionate, and its chemical structural formula (I) is as follows:

[0006]

[0007] The invention provides a method for preparing a heptadecyl imidazole high-efficiency corrosion inhibitor. The heptadecyl imidazole high-efficiency corrosion inhibitor is obtained by an addition reaction of 2-heptadecylimidazole and methyl methacrylate.

[0008] The present invention also provides a method for preparing the heptadecyl imidazole high-efficiency corrosion inhibitor, comprising the following steps:

[0009] Step 1: Weigh 2-heptadecylimidazole powder and methyl methacrylate liquid, and add them into two round-bottom flasks equipped with a stirrer, a thermometer and a reflux condenser. When adding methyl methacrylate, a polymerization inhibitor needs to be added at the same time. Subsequently, a solvent is slowly added to the reaction system to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A;

[0010] Step 2: Stir solution A, heat it for reflux reaction, and obtain a light yellow solution B. During the reflux process, adjust the reflux rate so that the condensate can flow back to the flask smoothly to avoid the accumulation of liquid in the condenser;

[0011] Step 3: Stop heating solution B, let it stand and cool to room temperature, and then perform vacuum distillation on solution B to obtain a light yellow solution C; the purpose of vacuum distillation is to remove the solvent and unreacted methyl methacrylate and 2-heptadecylimidazole in solution B to ensure the purity of solution C;

[0012] Step 4: After the vacuum distillation is completed, the solution C is cooled to room temperature and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0013] Furthermore, the preparation method of the heptadecyl imidazole high-efficiency corrosion inhibitor has the following reaction equation:

[0014]

[0015] Furthermore, in the preparation method of the heptadecyl imidazole high-efficiency corrosion inhibitor, the mass percentage of the 2-heptadecylimidazole in step 1 is 60.11-74.81%, the mass percentage of the methyl methacrylate is 24.45-39.29%, and the mass percentage of the inhibitor is 0.6-0.97%;

[0016] The polymerization inhibitor in step 1 is hydroquinone, and the function of the polymerization inhibitor is to prevent methyl methacrylate from polymerizing at high temperature;

[0017] The solvent in step 1 is ethanol, which has the advantages of strong dissolving power, easy evaporation, low price, environmental protection, renewable, high safety, etc., and is the best solvent.

[0018] Furthermore, in the preparation method of the heptadecyl imidazole high-efficiency corrosion inhibitor, the temperature of the heating for reflux reaction in step 2 is 80±1°C.

[0019] Furthermore, in the method for preparing the heptadecyl imidazole high-efficiency corrosion inhibitor, the reduced pressure distillation in step three is carried out at 50±1°C, and the distillation conditions are strictly controlled during the reduced pressure distillation reaction, the vacuum degree is set at 80-100 mmHg, and the distillation rate is controlled at 1-2 drops per second; the purpose of the reduced pressure distillation reaction is to remove the solvent and unreacted methyl methacrylate and 2-heptadecylimidazole in solution B to ensure the purity of solution C.

[0020] Furthermore, in the preparation method of the heptadecanediimidazole high-efficiency corrosion inhibitor, the mass percentages of the 2-heptadecanediimidazole, methyl methacrylate and inhibitor are 65.21%:34.14%:0.65%, and the heptadecanediimidazole high-efficiency corrosion inhibitor is prepared. In a 1M HCl solution, the dosage of the heptadecanediimidazole high-efficiency corrosion inhibitor is 300 mg / L, and the corrosion inhibition efficiency of Q235 steel reaches 98.11%.

[0021] The invention provides an application of a heptadecyl imidazole high-efficiency corrosion inhibitor for protecting steel in an acidic environment.

[0022] Furthermore, the application of protecting steel in acidic environment is used for industrial pickling of HCl solution and acidizing of oil and gas wells.

[0023] The beneficial effects of the present invention are:

[0024] Compared with the existing corrosion inhibitor and its preparation method, the present invention has low dosage, simple synthesis method, high efficiency, safety and environmental protection, and can be widely used in acidic environments such as industrial pickling and oil and gas well acidizing;

[0025] It has a highly effective corrosion inhibition effect on steel in 1M HCl solution, and a corrosion inhibition efficiency of up to 98.11% can be achieved when the dosage of the agent is 300 mg / L. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a graph of inhibitor concentration and corrosion rate in the static weight loss experiment in Example 1;

[0027] Figure 2 This is the SEM test image of Q235 steel in 1M HCl solution in Example 1;

[0028] Figure 3 This is a SEM test image of the corrosion inhibitor prepared in Example 1 on Q235 steel in 1M HCl solution. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0030] Example 1

[0031] 1. Synthesis of corrosion inhibitor

[0032] The specific preparation steps of the heptadecyl imidazole high-efficiency corrosion inhibitor are as follows:

[0033] Step 1: accurately weigh 5.00 g of 2-heptadecylimidazole powder and add it together with 8.48 mL of methyl methacrylate liquid into a two-mouth round-bottom flask equipped with a stirrer, a thermometer and a reflux condenser; when adding the methyl methacrylate raw material, add 0.65% of the total raw material as a polymerization inhibitor hydroquinone; then, slowly add 80 mL of anhydrous ethanol to the reaction system as a solvent to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; the mass percentage of 2-heptadecylimidazole and methyl methacrylate is 65.21%:34.14%; solution A is colorless;

[0034] Step 2: Stir solution A and heat it to 80±1°C. Reflux at this temperature for 5 hours to obtain a light yellow solution B. During the reflux process, adjust the reflux rate in time so that the condensate can flow back to the flask smoothly to avoid liquid accumulation in the condenser.

[0035] Step 3: Stop heating solution B, let it stand and cool to room temperature, then transfer solution B to a vacuum distillation apparatus, and perform vacuum distillation at a heating temperature of 50±1°C for 4 hours to obtain a light yellow solution C; during the vacuum distillation reaction, the distillation conditions must be strictly controlled, the vacuum degree is set at 100 mmHg, and the distillation rate is controlled at 2 drops per second;

[0036] Step 4: After the vacuum distillation is completed, the obtained solution C is cooled to room temperature, and then ground in a mortar to obtain a beige powder D, which is a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0037] 2. Static weightlessness experiment

[0038] (1) According to the experimental requirements, a blank acidic medium and an acidic medium solution with different concentrations of corrosion inhibitors added were prepared, and the acidic medium was 1 M HCl solution;

[0039] (2) The Q235 sample was polished step by step with 240#~1000# metallographic water-abrasive paper, then degreased with acetone, rinsed with distilled water, dehydrated with anhydrous ethanol, dried with a hair dryer, and placed in a dryer for later use;

[0040] (3) Use a high-precision balance (electronic balance, precision) to measure the initial mass (W0) of the Q235 sample;

[0041] (4) The pretreated Q235 sample was suspended in a predetermined corrosive medium and maintained at a constant temperature (25±3°C) for 72 hours;

[0042] (5) After immersion, remove the Q235 sample from the corrosive medium, remove the corrosion products on the surface of the sample, rinse it with distilled water and anhydrous ethanol in turn, dry it with a hair dryer, and place it in a drying oven for 1 hour;

[0043] (6) Use the same high-precision balance to measure the mass (Wt) of the sample after corrosion;

[0044] (7) Experimental results and calculations:

[0045] The corrosion rate calculation formula is shown in formula 1:

[0046]

[0047] Where: W0-mass of the sample before corrosion, g; Wt-mass of the sample after corrosion, g; t-immersion time, h; s-surface area of ​​the sample, cm 2 ;

[0048] The calculation formula of corrosion inhibition efficiency is shown in formula 2:

[0049]

[0050] Where: W corr - The corrosion rate of the metal without adding corrosion inhibitor (the mass of metal corroded per unit area per unit time); -The corrosion rate of metal after adding corrosion inhibitor.

[0051] 3. Experimental results

[0052] The relationship between the concentration of corrosion inhibitor and corrosion inhibition efficiency is shown in the attached figure. Figure 1 As shown in the figure, it can be seen that with the increase of the corrosion inhibitor concentration, the corrosion rate gradually decreases and the corrosion inhibition efficiency gradually increases; Table 1 is a static weight loss test result table of each embodiment. As shown in 1 and 2 in Table 1, when the corrosion inhibitor concentration is 200 mg / L, the corrosion inhibition efficiency reaches 96.94%, and when the corrosion inhibitor concentration is 300 mg / L, the corrosion inhibition efficiency reaches the maximum value of 98.11%; Appendix Figure 2 , 3 The SEM test images of the sample in an acidic medium solution and an acidic medium solution to which the corrosion inhibitor prepared in Example 1 is added are respectively shown. It can be clearly seen that after the corrosion inhibitor prepared in Example 1 is added, the degree of corrosion on the carbon steel surface is significantly reduced, and the accumulation of corrosion products is almost not observed, showing a relatively flat and smooth surface morphology.

[0053] Example 2

[0054] 1. Synthesis of corrosion inhibitor

[0055] The preparation of heptadecyl imidazole high-efficiency corrosion inhibitor is carried out in the following steps:

[0056] Step 1: accurately weigh 5.00 g of 2-heptadecylimidazole powder and add it together with 5.30 mL of methyl methacrylate liquid into a two-mouth round-bottom flask equipped with a stirrer, a thermometer and a reflux condenser; when adding the methyl methacrylate raw material, it is necessary to add 0.74% of the total raw material as a polymerization inhibitor hydroquinone; then, slowly add 80 mL of anhydrous ethanol to the reaction system as a solvent to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; the mass percentage of 2-heptadecylimidazole and methyl methacrylate is 74.81%:24.45%;

[0057] Step 2: Stir solution A and heat it to 80±1°C, and reflux it for 5 hours to obtain a light yellow solution B;

[0058] Step 3: Stop heating solution B, let it stand and cool to room temperature, then transfer solution B to a vacuum distillation apparatus, set the vacuum degree at 100 mmHg, control the distillation rate at 2 drops per second, and perform vacuum distillation at a heating temperature of 50±1°C for 4 hours to obtain a light yellow solution C;

[0059] Step 4: After the reduced pressure distillation is completed, the obtained solution C is cooled to room temperature, and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0060] 2. Static weightlessness experiment

[0061] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor was calculated.

[0062] 3. Experimental results

[0063] As shown in 3 and 4 of Table 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor is 79.44% when the dosage is 300 mg / L; and when the dosage is increased to 400 mg / L, the corrosion inhibition efficiency is further improved to 92.92%.

[0064] Example 3

[0065] 1. Synthesis of corrosion inhibitor

[0066] The preparation of heptadecyl imidazole high-efficiency corrosion inhibitor is carried out in the following steps:

[0067] Step 1: accurately weigh 5.00 g of 2-heptadecylimidazole powder and add it together with 6.89 mL of methyl methacrylate liquid into a two-mouth round-bottom flask equipped with a stirrer, a thermometer and a reflux condenser; when adding the methyl methacrylate raw material, a polymerization inhibitor hydroquinone accounting for 0.71% of the total raw material should be added at the same time; then, 80 mL of anhydrous ethanol is slowly added to the reaction system as a solvent to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; the mass percentage of 2-heptadecylimidazole and methyl methacrylate is 69.74%:29.55%;

[0068] Step 2: Stir solution A and heat it to 80±1°C, and reflux it for 5 hours to obtain a light yellow solution B;

[0069] Step 3: Stop heating solution B, let it stand and cool to room temperature, then transfer solution B to a vacuum distillation apparatus, set the vacuum degree at 100 mmHg, control the distillation rate at 2 drops per second, and perform vacuum distillation at a heating temperature of 50±1°C for 4 hours to obtain a light yellow solution C;

[0070] Step 4: After the reduced pressure distillation is completed, the obtained solution C is cooled to room temperature, and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0071] 2. Static weightlessness experiment

[0072] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor was calculated.

[0073] 3. Experimental results

[0074] As shown in 5 and 6 in Table 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor is 85.24% when the dosage is 300 mg / L; and when the dosage is increased to 400 mg / L, the corrosion inhibition efficiency is further improved to 94.04%.

[0075] Example 4

[0076] 1. Synthesis of corrosion inhibitor

[0077] The preparation of heptadecyl imidazole high-efficiency corrosion inhibitor is carried out in the following steps:

[0078] Step 1: accurately weigh 5.00 g of 2-heptadecylimidazole powder and add it together with 10.60 mL of methyl methacrylate liquid into a two-mouth round-bottom flask equipped with a stirrer, a thermometer and a reflux condenser; when adding the methyl methacrylate raw material, a polymerization inhibitor hydroquinone accounting for 0.6% of the total raw material should be added at the same time; then, 80 mL of anhydrous ethanol is slowly added to the reaction system as a solvent to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; the mass percentage of 2-heptadecylimidazole and methyl methacrylate is 60.11%:39.29%;

[0079] Step 2: Stir solution A and heat it to 80±1°C, and reflux it for 5 hours to obtain a light yellow solution B;

[0080] Step 3: Stop heating solution B, let it stand and cool to room temperature, then transfer solution B to a vacuum distillation apparatus, set the vacuum degree at 100 mmHg, control the distillation rate at 2 drops per second, and perform vacuum distillation at a heating temperature of 50±1°C for 4 hours to obtain a light yellow solution C;

[0081] Step 4: After the reduced pressure distillation is completed, the obtained solution C is cooled to room temperature, and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0082] 2. Static weightlessness experiment

[0083] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the corrosion inhibitor prepared in this Example 4 was calculated.

[0084] 3. Experimental results

[0085] As shown in 7 and 8 in Table 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor is 89.31% when the dosage is 300 mg / L; and when the dosage is increased to 400 mg / L, the corrosion inhibition efficiency is further increased to 95.44%.

[0086] Example 5

[0087] 1. Synthesis of corrosion inhibitor

[0088] The preparation of heptadecyl imidazole high-efficiency corrosion inhibitor is carried out in the following steps:

[0089] Step 1: accurately weigh 5.00 g of 2-heptadecylimidazole powder and add it together with 8.48 mL of methyl methacrylate liquid into a two-mouth round-bottom flask equipped with a stirrer, a thermometer and a reflux condenser; when adding the methyl methacrylate raw material, a polymerization inhibitor hydroquinone accounting for 0.97% of the total raw material should be added at the same time; then, 80 mL of anhydrous ethanol is slowly added to the reaction system as a solvent to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; the mass percentage of 2-heptadecylimidazole and methyl methacrylate is 65.00%:34.03%;

[0090] Step 2: Stir solution A and heat it to 80±1°C, and reflux it for 5 hours to obtain a light yellow solution B;

[0091] Step 3: Stop heating solution B, let it stand and cool to room temperature, then transfer solution B to a vacuum distillation apparatus, and perform vacuum distillation at a heating temperature of 50±1°C for 4 hours to obtain a light yellow solution C; during the vacuum distillation reaction, the distillation conditions must be strictly controlled, the vacuum degree is set at 80 mmHg, and the distillation rate is controlled at 2 drops per second;

[0092] Step 4: After the reduced pressure distillation is completed, the obtained solution C is cooled to room temperature, and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

[0093] 2. Static weightlessness experiment

[0094] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor was calculated.

[0095] 3. Experimental results

[0096] As shown in Table 1, 9, the corrosion inhibition efficiency of the prepared corrosion inhibitor is not much different from that of the corrosion inhibitor prepared in Example 1. When the dosage of 300 mg / L is added, the corrosion inhibition efficiency is 97.42%.

[0097] Example 6

[0098] 1. Synthesis of corrosion inhibitor

[0099] The heptadecyl imidazole high-efficiency corrosion inhibitor was prepared according to the method for preparing the corrosion inhibitor in Example 1.

[0100] 2. Static weightlessness experiment

[0101] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor was calculated when the corrosion inhibitor addition amount was 300 mg / L and the acidic medium was 3M HCl solution.

[0102] 3. Experimental results

[0103] As shown in Table 10, when the prepared corrosion inhibitor is added at a dosage of 300 mg / L and the acidic medium is 3M HCl solution, the corrosion inhibition efficiency is 96.97%.

[0104] Example 7

[0105] 1. Synthesis of corrosion inhibitor

[0106] The heptadecyl imidazole high-efficiency corrosion inhibitor was prepared according to the method for preparing the corrosion inhibitor in Example 1.

[0107] 2. Static weightlessness experiment

[0108] According to the setting of the static weight loss experiment in Example 1, the corrosion inhibition efficiency of the prepared corrosion inhibitor was calculated when the corrosion inhibitor addition amount was 300 mg / L and the acidic medium was 6M HCl solution.

[0109] 3. Experimental results

[0110] As shown in 11 of Table 1, when the prepared corrosion inhibitor is added at a dosage of 300 mg / L and the acidic medium is 6M HCl solution, the corrosion inhibition efficiency is 97.40%.

[0111] Table 1 Static weight loss test results of Examples 1-7

[0112]

[0113] It can be seen from the results of the above-mentioned embodiments that the heptadecanediimidazole high-efficiency corrosion inhibitor and its preparation method of the present invention, compared with the existing corrosion inhibitor and its preparation method, have low dosage, simple synthesis method, high efficiency, safety and environmental protection of the product; in acidic environments such as industrial pickling and oil and gas well acidizing, compared with conventional imidazole corrosion inhibitors, a lower dosage can provide efficient corrosion protection for steel, especially in 1M HCl solution, a dosage of 300 mg / L can obtain a corrosion inhibition efficiency of up to 98.11%.

Claims

1. A heptadecyl imidazole high efficiency corrosion inhibitor, characterized in that: The heptadecyl imidazole high-efficiency corrosion inhibitor is methyl 3-(2-heptadecylimidazole)-2-methyl propionate, and its chemical structural formula (I) is as follows:

2. A method for preparing the heptadecyl imidazole high-efficiency corrosion inhibitor according to claim 1, characterized in that: The heptadecanediimidazole high-efficiency corrosion inhibitor is obtained by the addition reaction of 2-heptadecanediimidazole and methyl methacrylate.

3. The preparation method according to claim 2, characterized in that: The steps include: Step 1: Weigh 2-heptadecylimidazole powder and methyl methacrylate liquid, and add them into two round-bottom flasks equipped with a stirrer, a thermometer and a reflux condenser. When methyl methacrylate is added, an inhibitor needs to be added at the same time. Subsequently, a solvent is slowly added into the reaction system to promote sufficient contact and mixing between the reactants to form a uniform colorless solution A; Step 2: Stir solution A, heat it for reflux reaction, and obtain a light yellow solution B. During the reflux process, adjust the reflux rate so that the condensate can flow smoothly back into the flask to avoid liquid accumulation in the condenser; Step 3: Stop heating solution B, let it stand and cool to room temperature, then distill solution B under reduced pressure to obtain a light yellow solution C; Step 4: After the vacuum distillation is completed, the solution C is cooled to room temperature and then ground in a mortar to obtain powder D, i.e., a heptadecyl imidazole-based high-efficiency corrosion inhibitor.

4. The preparation method according to claim 2 or 3, characterized in that: The reaction equation is as follows:

5. The preparation method according to claim 3, characterized in that: The mass percentage of the 2-heptadecylimidazole in step 1 is 60.11-74.81%, the mass percentage of the methyl methacrylate is 24.45-39.29%, and the mass percentage of the inhibitor is 0.6-0.97%; The inhibitor in step 1 is hydroquinone; The solvent in step 1 is ethanol.

6. The preparation method according to claim 3 or 5, characterized in that: The temperature for heating to perform reflux reaction in step 2 is 80±1°C.

7. The preparation method according to claim 6, characterized in that: The reduced pressure distillation in step 3 is carried out at 50±1° C. During the reduced pressure distillation reaction, the distillation conditions are strictly controlled, the vacuum degree is set at 80-100 mmHg, and the distillation rate is controlled at 1-2 drops per second.

8. The preparation method according to claim 5, characterized in that: The mass percentages of the 2-heptadecylimidazole, methyl methacrylate, and inhibitor are 65.21%:34.14%:0.65%, and a heptadecylimidazole-based efficient corrosion inhibitor is prepared. In a 1M HCl solution, when the heptadecylimidazole-based efficient corrosion inhibitor is added in an amount of 300 mg / L, the corrosion inhibition efficiency of Q235 steel reaches 98.11%.

9. Use of the heptadecyl imidazole high-efficiency corrosion inhibitor according to claim 1 for protecting steel in an acidic environment.

10. The use of protecting steel in an acidic environment as claimed in claim 9, characterized in that: Used for industrial pickling with HCl solution and acidizing of oil and gas wells.

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