Preparation method and application of an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end

Abstract

The present invention belongs to the field of chemical engineering applications, and particularly relates to a preparation method and application of an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end. The preparation method is to react acrylic acid with anhydrous piperazine to obtain 1,4-bis(2-carboxyethyl)piperazine, then react 1,4-bis(2-carboxyethyl)piperazine with diethylenetriamine to synthesize piperazine gemini imidazoline, and then react with a long-chain halogenated hydrocarbon through N-alkylation reaction to obtain an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end. The characteristics of this corrosion inhibitor are that the adsorption end contains a piperazine ring and two imidazoline rings, has multiple adsorption sites, can achieve the maximum coverage of the metal surface during the adsorption process, form a more dense and stable protective film, and has good dispersibility in aqueous solution, and can maintain long-term corrosion inhibition.

Description

Technical Field

[0001] The present invention belongs to the field of chemical engineering applications, and relates to a preparation method and application of an imidazoline corrosion inhibitor for aqueous phase, specifically to a preparation method and application of an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end. Background Art

[0002] The corrosion of metal materials exists in almost all fields of industrial production and living facilities, causing huge losses and hazards to society, and even possibly triggering serious safety production accidents. Adding corrosion inhibitors for anti-corrosion has the advantages of strong operability, high economic benefits, quick results, and overall protection, and has become one of the effective means to prevent the corrosion of metal equipment. Imidazoline corrosion inhibitors have the advantages of being green, non-toxic, and having good corrosion inhibition effects, thus receiving continuous attention.

[0003] Early imidazoline corrosion inhibitors were prepared from fatty acids such as oleic acid and diethylenetriamine. However, such imidazoline corrosion inhibitors have the disadvantages of low adsorption strength and easy desorption. In order to have more adsorption sites and form a dense and stable adsorption film on the metal surface, industry researchers have gradually developed corrosion inhibitors with multiple imidazoline rings. For example, Patent CN108164465A uses lauric acid monocyclic imidazoline and 1,3-dibromopropane to synthesize a corrosion inhibitor containing bicyclic imidazoline; however, such corrosion inhibitors are mostly oil-soluble corrosion inhibitors and are poorly dispersed when used in an aqueous phase system, resulting in poor corrosion inhibition effects.

[0004] In order to improve water solubility, it is generally made into a quaternary ammonium salt type imidazoline. Currently, most of the common imidazoline corrosion inhibitors on the market are of the quaternary ammonium salt type. For example, Patent CN111995578A uses oleic acid and diethylenetriamine as raw materials to obtain oleic acid imidazoline, then undergoes an N-alkylation reaction with dichloroethane to generate a gemini imidazoline intermediate, and finally uses chloroacetic acid as a quaternization reagent to prepare a gemini imidazoline quaternary ammonium salt; CN103289671B uses fatty acids and polyamines to react to generate an imidazoline intermediate, then undergoes quaternization with benzyl chloride, and finally uses dichlorobutane or dibromobutane as a linker to prepare a gemini imidazoline-based quaternary ammonium salt. However, such quaternary ammonium salt corrosion inhibitors contain halogen chloride ions, and long-term use will damage the metal oxide film protective layer, forming pitting corrosion or crevice corrosion, and instead corrode the metal to a certain extent. And research shows that most organic chlorides have carcinogenic, teratogenic, and mutagenic effects, endangering human health. Therefore, they have been banned by relevant departments, and it is required that the content of organic chlorine in various corrosion inhibitors shall not be greater than 3 μg / g.

[0005] Therefore, overcoming the disadvantages of the existing imidazoline corrosion inhibitors, such as poor adsorption, poor water solubility, or containing halogen ions, and developing a non-quaternary ammonium salt type water-soluble imidazoline corrosion inhibitor with excellent corrosion inhibition performance and adsorption performance, is a problem that the industry needs to solve. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method and application of an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end. This type of corrosion inhibitor has the following structure:

[0007]

[0008] Among them, R is a straight-chain hydrocarbon group with 10 to 20 carbon atoms.

[0009] The imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end of the present invention is a non-quaternary ammonium salt type multi-adsorption site corrosion inhibitor, which can be applied to the treatment of high-flow oil and gas gathering and transportation pipelines containing CO2 / H2S and high-flow acidic produced water. The characteristics of this corrosion inhibitor are that the adsorption end contains a piperazine ring and two imidazoline rings, with multiple adsorption sites, which can achieve the maximum coverage of the metal surface during the adsorption process, form a denser and more stable protective film, and has good dispersibility in aqueous solution, and can maintain long-term corrosion inhibition.

[0010] The present invention also provides a preparation method of an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end, which specifically includes the following steps:

[0011] (1) React anhydrous piperazine with acrylic acid to obtain 1,4-bis(2-carboxyethyl)piperazine;

[0012] Among them, the molar ratio of acrylic acid to anhydrous piperazine is 2.5 to 2;

[0013] The reaction solvent can be one or a mixture of several of methanol, ethanol, and isopropanol.

[0014] The preferred molar ratio of acrylic acid to anhydrous piperazine raw materials is 2.1:1, and the preferred solvent is ethanol.

[0015] (2) React 1,4-bis(2-carboxyethyl)piperazine with diethylenetriamine through amidation and cyclization reactions to generate piperazine gemini imidazoline;

[0016] Among them, the molar ratio of diethylenetriamine to 1,4-bis(2-carboxyethyl)piperazine is 3 to 2;

[0017] Add a water-carrying agent to promote the reaction. The water-carrying agent can be one or a mixture of several of benzene, toluene, and xylene;

[0018] The reaction temperature is 140 to 230 °C, and the reaction time is 6 to 12 h.

[0019] The preferred molar ratio of diethylenetriamine to 1,4-bis(2-carboxyethyl)piperazine is 2.5:1.

[0020] The preferred reaction temperature is 160 to 210 °C, and the preferred reaction time is 8 to 10 h.

[0021] The preferred water-carrying agent is xylene.

[0022] (3) Under the action of an acid-binding agent, piperazine bis-imidazoline reacts with a long-chain halogenated hydrocarbon through an N-alkylation reaction to obtain an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end.

[0023] Among them, the long-chain halogenated hydrocarbons include: decyl bromide, dodecyl bromide, tetradecyl bromide, hexadecyl bromide, decyl chloride, dodecyl chloride, tetradecyl chloride, hexadecyl chloride;

[0024] The molar ratio of the long-chain halogenated hydrocarbon to piperazine bis-imidazoline is 1.5 - 1;

[0025] The acid-binding agents include: triethylamine, pyridine, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate;

[0026] The molar ratio of the acid-binding agent to the long-chain halogenated hydrocarbon is 1.3 - 1.

[0027] The reaction temperature is 60 - 100 °C, and the reaction time is 1 - 3 h.

[0028] The molar ratio of piperazine bis-imidazoline to the long-chain halogenated hydrocarbon is preferably 1.2:1.

[0029] The acid-binding agent is preferably triethylamine.

[0030] The molar ratio of the acid-binding agent to the long-chain halogenated hydrocarbon is preferably 1.1:1.

[0031] The reaction temperature is preferably 70 - 80 °C.

[0032] Beneficial effects: The present invention provides a preparation method and application of a class of imidazoline corrosion inhibitors with multiple nitrogen atoms at the adsorption end. The characteristics of this corrosion inhibitor are that the adsorption end contains a piperazine ring and two imidazoline rings, has multiple adsorption sites, can achieve the maximum surface coverage during the adsorption process, form a denser and more stable protective film, and has good dispersibility in aqueous solution, and can maintain long-term corrosion inhibition. This corrosion inhibitor can be applied to the treatment process of high-flow oil and gas gathering and transportation pipelines containing CO2 / H2S and high-flow acidic produced water. Description of the Drawings

[0033] Figure 1 It is the infrared spectrum of 1,4-bis(2-carboxyethyl)piperazine.

[0034] Figure 2 It is the infrared spectrum of the imidazoline corrosion inhibitor ① with multiple nitrogen atoms at the adsorption end. Detailed Embodiments

[0035] The following is an exemplary illustration and further understanding of the present application in combination with specific embodiments. However, the embodiments are only given as examples and are not regarded as the entire technical solution of the present invention, nor are they a limitation on the overall technical solution of the present invention. Any simple changes or substitutions with the same or similar technical features fall within the protection scope of the present invention.

[0036] Example 1

[0037] Add anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol into a 250 mL four-necked flask equipped with a thermometer and mechanical stirrer. Stir and dissolve at room temperature, and slowly add acrylic acid (0.22 mol, 15.90 g). After the addition is complete, continue stirring, and white solids will precipitate out; until the white solids no longer increase, perform suction filtration on the obtained solid-liquid mixture, wash the filter cake with ethanol 3 times, and dry it under vacuum to obtain product 1,4-bis(2-carboxyethyl)piperazine (the infrared spectrum is as shown in the appendix Figure 1 ), and the yield is 99.13%.

[0038] Appendix Figure 1 In the range of 3200 - 2500 cm -1 around is the characteristic peak of the hydroxyl group in the carboxyl group, and 1659 cm -1 is the absorption peak of the carbonyl group, indicating the synthesis of 1,4-bis(2-carboxyethyl)piperazine.

[0039] Take 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 11.51 g) and diethylenetriamine (0.10 mol, 10.31 g) and add them into a dry 250 mL three-necked flask equipped with a thermometer, reflux condenser, and mechanical stirrer. Turn on the stirring device, then add 50 mL of xylene as a solvent and a water-carrying agent, slowly heat up to 150 °C for reflux, insert a water separator to dehydrate, and react for 3 h; continue to heat up to 190 °C for cyclization reaction for 6 h. When the amount of water in the water separator no longer increases, stop the reaction to obtain piperazine-based gemini imidazoline.

[0040] Continue to add the acid-binding agent triethylamine (0.05 mol, 3.16 g) to the three-necked flask of piperazine-based gemini imidazoline, stir evenly, heat up to 70 °C, and slowly add bromododecane (0.05 mol, 12.46 g). After the addition is complete, react for 5 h. Solids will precipitate out. Perform suction filtration on the obtained solid-liquid mixture to remove the triethylamine salt; wash the filter cake with xylene 2 - 3 times and combine it with the filtrate; wash the filtrate with 10 mL of distilled water to remove the unreacted piperazine-based gemini imidazoline, separate the organic layer, and perform vacuum distillation to obtain imidazoline corrosion inhibitor ① with multiple nitrogen atoms at the adsorption end (the infrared spectrum is as shown in the appendix Figure 2 ), and the yield is 97.93%.

[0041] Appendix Figure 2 In the range of 3423 cm -1is the characteristic peak of N-H; 2935 cm -1 and 2820 cm -1 are the characteristic peaks of methyl and methylene; 1608 cm -1 is the characteristic absorption peak of C=N in the imidazoline ring; 721 cm -1 is the absorption peak of more than four consecutive methylenes, indicating the synthesis of the imidazoline corrosion inhibitor ① product with multiple nitrogen atoms at the adsorption end.

[0042] Example 2

[0043] Add anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol to a 250 mL four-necked flask equipped with a thermometer and mechanical stirrer. Stir and dissolve at room temperature, and slowly add acrylic acid (0.20 mol, 14.41 g). After the addition is complete, continue stirring, and white solids will precipitate out; until the white solids no longer increase, filter the obtained solid-liquid mixture by suction filtration, wash the filter cake with ethanol 3 times, and dry it under vacuum to obtain the product 1,4-bis(2-carboxyethyl)piperazine with a yield of 98.85%.

[0044] Take 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 11.51 g) and diethylenetriamine (0.12 mol, 12.38 g) and add them to a dry 250 mL three-necked flask equipped with a thermometer, reflux condenser, and mechanical stirrer. Turn on the stirring device, then add 50 mL of xylene as a solvent and a water-carrying agent, slowly heat up to 150 °C and reflux, insert a water separator to dehydrate, and react for 3 h; continue to heat up to 210 °C for cyclization reaction for 8 h. When the amount of water in the water separator no longer increases, stop the reaction to obtain piperazine gemini imidazoline.

[0045] Continue to add the acid-binding agent pyridine (0.06 mol, 4.74 g) to the three-necked flask of piperazine gemini imidazoline, stir evenly, heat up to 70 °C, and slowly add bromotetradecane (0.06 mol, 16.63 g). After the addition is complete, react for 5 h. Solids will precipitate out. Filter the obtained solid-liquid mixture by suction filtration to remove the pyridine salt; wash the filter cake with xylene 2-3 times and combine it with the filtrate; wash the filtrate with 10 mL of distilled water to remove the unreacted piperazine gemini imidazoline, pyridine, and diethylenetriamine, separate the organic layer, and distill it under reduced pressure to obtain the imidazoline corrosion inhibitor ② with multiple nitrogen atoms at the adsorption end, with a yield of 98.15%.

[0046] Example 3

[0047] Add anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol into a 250 mL four-necked flask equipped with a thermometer and mechanical stirrer. Stir and dissolve at room temperature, and slowly add acrylic acid (0.20 mol, 14.41 g). After the addition is complete, continue stirring, and white solids will precipitate out; until the amount of white solids no longer increases, perform suction filtration on the obtained solid-liquid mixture, wash the filter cake with ethanol 3 times, and dry it under vacuum to obtain the product 1,4-bis(2-carboxyethyl)piperazine, with a yield of 98.93%.

[0048] Take 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 11.51 g) and diethylenetriamine (0.12 mol, 12.38 g) and add them into a dry 250 mL three-necked flask equipped with a thermometer, reflux condenser, and mechanical stirrer. Turn on the stirring device, then add 50 mL of xylene as a solvent and a water-carrying agent, slowly heat up to 150 °C for reflux, insert a water separator to dehydrate, and react for 3 h; continue to heat up to 200 °C for cyclization reaction for 7 h. When the amount of water in the water separator no longer increases, stop the reaction to obtain piperazine gemini imidazoline.

[0049] Continue to add the acid-binding agent pyridine (0.05 mol, 3.95 g) to the three-necked flask of piperazine gemini imidazoline, stir evenly, heat to 70 °C, and slowly add chlorotetradecane (0.05 mol, 11.64 g). After the addition is complete, react for 5 h. Solids will precipitate out. Perform suction filtration on the obtained solid-liquid mixture to remove pyridine hydrochloride; wash the filter cake with xylene 2 - 3 times and combine it with the filtrate; wash the filtrate with 10 mL of distilled water to remove unreacted piperazine gemini imidazoline, triethylamine, and diethylenetriamine, separate the organic layer, and perform vacuum distillation to obtain the imidazoline corrosion inhibitor ③ with multiple nitrogen atoms at the adsorption end, with a yield of 98.43%.

[0050] Example 4

[0051] Add anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol into a 250 mL four-necked flask equipped with a thermometer and mechanical stirrer. Stir and dissolve at room temperature, and slowly add acrylic acid (0.21 mol, 15.13 g). After the addition is complete, continue stirring, and white solids will precipitate out; until the amount of white solids no longer increases, perform suction filtration on the obtained solid-liquid mixture, wash the filter cake with ethanol 3 times, and dry it under vacuum to obtain the product 1,4-bis(2-carboxyethyl)piperazine, with a yield of 99.08%.

[0052] 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 11.51 g) and diethylenetriamine (0.15 mol, 15.48 g) were added into a dry 250 mL three-necked flask equipped with a thermometer, a reflux condenser and a mechanical stirrer. The stirring device was turned on, and then 50 mL of xylene was added as a solvent and a water-carrying agent. The temperature was slowly raised to 160 °C for reflux, and a water separator was inserted to dehydrate the reaction for 3 h; the temperature was further raised to 210 °C for cyclization reaction for 7 h. When the amount of water in the water separator no longer increased, the reaction was stopped to obtain piperazine bis-imidazoline.

[0053] Triethylamine (0.05 mol, 5.06 g), as an acid-binding agent, was added to the three-necked flask containing piperazine bis-imidazoline and stirred evenly. The temperature was heated to 70 °C, and chlorohexadecane (0.05 mol, 13.04 g) was slowly added dropwise. After the addition was completed, the reaction was carried out for 5 h. A solid precipitated out. The obtained solid-liquid mixture was filtered by suction to remove the triethylamine salt; the filter cake was washed with xylene 2-3 times and combined into the filtrate; the filtrate was washed with 10 mL of distilled water to remove the unreacted piperazine bis-imidazoline and diethylenetriamine, and the organic layer was separated. The imidazoline corrosion inhibitor ④ containing multiple nitrogen atoms at the adsorption end was obtained by vacuum distillation, and the yield was 96.42%.

[0054] Example 5

[0055] Anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol were added to a 250 mL four-necked flask equipped with a thermometer and a mechanical stirrer. It was stirred and dissolved at room temperature, and acrylic acid (0.21 mol, 15.13 g) was slowly added dropwise. After the addition was completed, stirring was continued, and a white solid precipitated out; until the white solid no longer increased, the obtained solid-liquid mixture was filtered by suction, and the filter cake was washed with ethanol 3 times and dried in vacuum to obtain the product 1,4-bis(2-carboxyethyl)piperazine, and the yield was 99.10%.

[0056] 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 11.51 g) and diethylenetriamine (0.15 mol, 15.48 g) were added into a dry 250 mL three-necked flask equipped with a thermometer, a reflux condenser and a mechanical stirrer. The stirring device was turned on, and then 50 mL of xylene was added as a solvent and a water-carrying agent. The temperature was slowly raised to 160 °C for reflux, and a water separator was inserted to dehydrate the reaction for 3 h; the temperature was further raised to 210 °C for cyclization reaction for 7 h. When the amount of water in the water separator no longer increased, the reaction was stopped to obtain piperazine bis-imidazoline.

[0057] Continue to add the acid-binding agent triethylamine (0.04 mol, 6.08 g) to the three-necked flask of piperazine bis-imidazoline, stir evenly, heat to 70 °C, and slowly dropwise add hexadecyl chloride (0.06 mol, 15.64 g). After the addition is complete, react for 5 h. Solids precipitate out. Perform suction filtration on the obtained solid-liquid mixture to remove the triethylamine salt; wash the filter cake with xylene 2-3 times and combine it with the filtrate; wash the filtrate with 10 mL of distilled water to remove unreacted piperazine bis-imidazoline and diethylenetriamine, separate the organic layer, and perform vacuum distillation to obtain the imidazoline corrosion inhibitor ⑤ with multiple nitrogen atoms at the adsorption end, and the yield is 97.33%.

[0058] Example 6

[0059] Add anhydrous piperazine (0.1 mol, 8.61 g) and 50 mL of ethanol to a 250 mL four-necked flask equipped with a thermometer and mechanical stirrer, stir and dissolve at room temperature, and slowly dropwise add acrylic acid (0.25 mol, 18.01 g). After the addition is complete, continue to stir, and white solids precipitate out; until the white solids no longer increase, perform suction filtration on the obtained solid-liquid mixture, wash the filter cake with ethanol 3 times, and vacuum dry to obtain the product 1,4-bis(2-carboxyethyl)piperazine, and the yield is 99.12%.

[0060] Take 1,4-bis(2-carboxyethyl)piperazine (0.05 mol, 13.81 g) and diethylenetriamine (0.12 mol, 12.38 g) and add them to a dry 250 mL three-necked flask equipped with a thermometer, reflux condenser, and mechanical stirrer. Turn on the stirring device, then add 50 mL of xylene as a solvent and a water-carrying agent, slowly heat up to 160 °C for reflux, insert a water separator to dehydrate, and react for 3 h; continue to heat up to 210 °C and carry out a cyclization reaction for 7 h. When the amount of water in the water separator no longer increases, stop the reaction to obtain piperazine bis-imidazoline.

[0061] Continue to add the acid-binding agent triethylamine (0.075 mol, 7.59 g) to the three-necked flask of piperazine bis-imidazoline, stir evenly, heat to 70 °C, and slowly dropwise add hexadecyl chloride (0.075 mol, 19.45 g). After the addition is complete, react for 5 h. Solids precipitate out. Perform suction filtration on the obtained solid-liquid mixture to remove the triethylamine salt; wash the filter cake with xylene 2-3 times and combine it with the filtrate; wash the filtrate with 10 mL of distilled water to remove unreacted piperazine bis-imidazoline and diethylenetriamine, separate the organic layer, and perform vacuum distillation to obtain the imidazoline corrosion inhibitor ⑥ with multiple nitrogen atoms at the adsorption end, and the yield is 98.08%.

[0062] Example 7 Effect Experiment

[0063] (1) HLB Value Test

[0064] The experiment referred to the performance evaluation method of corrosion inhibitors for produced water in oilfields SY / T 5273-2000. The imidazoline corrosion inhibitors with multiple nitrogen atoms at the adsorption end prepared in Examples 1-6 were compared. Equal masses of the synthesized products were weighed, and the dissolution and dispersion of the corrosion inhibitors in water were observed. The dissolution properties and HLB values of the corrosion inhibitors in water are shown in Table 1:

[0065] Table 1

[0066] Product Phenomenon HLB value Product Phenomenon HLB value Example 1 Transparent solution >13 Example 4 Semi-transparent to transparent dispersion 10～13 Example 2 Semi-transparent to transparent dispersion 10～13 Example 5 Semi-transparent to transparent dispersion 10～13 Example 3 Semi-transparent to transparent dispersion 10～13 Example 6 Semi-transparent to transparent dispersion 10～13

[0067] From the test results in Table 1 above, it can be seen that this type of imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end has good water solubility and dispersibility.

[0068] (2) Corrosion inhibition performance experiment

[0069] The experiment referred to the performance evaluation method of corrosion inhibitors for produced water in oilfields SY / T 5273-2000, and the corrosion inhibition rate was tested using the rotating coupon weight loss method.

[0070] Using 1mol / L H2SO4 solution as the acidic corrosion system, steel sheets with a specification of 5.0×2.5×0.2 cm 3 20 # were used as the corrosion test materials. The corrosion inhibition rates of the corrosion inhibitors with addition amounts of 0.05g / L, 0.10g / L, 0.15g / L, and 0.20g / L on 20 # carbon steel were tested at a temperature of 30℃, a rotation speed of 100r / min, and a corrosion time of 6h; when the temperature was 30℃, the rotation speed was 150r / min, and the addition amount was 0.20g / L, the corrosion inhibition rates of the corrosion inhibitors with corrosion times of 6h, 12h, 36h, and 48h on 20 # carbon steel were tested. The halogen-free water-soluble long-chain imidazoline prepared in Examples 1, 2, 3, 4, 5, and 6 was compared with the commercially available oleic acid imidazoline quaternary ammonium salt modified by quaternization

[0071] According to the formula, the corrosion inhibition rate was calculated, where △m0 was the mass loss of the steel sheet in the blank test; △m1 was the mass loss of the steel sheet in the test after adding the corrosion inhibitor.

[0072] When the temperature was 30℃, the rotation speed was 100r / min, and the corrosion time was 6h, the change results of the corrosion inhibition rates of the imidazolines with multiple nitrogen atoms at the adsorption end prepared in Examples 1, 2, 3, 4, 5, and 6 and the commercially available oleic acid imidazoline quaternary ammonium salt with the addition amount are shown in Table 2.

[0073] Table 2

[0074]

[0075]

[0076] The experimental results show that the imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end prepared by the present invention exhibits good corrosion inhibition performance even when added in small amounts.

[0077] At a temperature of 30 °C, a rotation speed of 150 r / min, and an addition amount of 0.20 g / L, the variation results of the corrosion inhibition rates of the imidazolines with multiple nitrogen atoms at the adsorption end prepared in Examples 1-6 and the commercially available oleic acid imidazoline quaternary ammonium salt with the corrosion time are shown in Table 3.

[0078] Table 3

[0079]

[0080]

[0081] The experimental results show that: the imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end prepared by the present invention can still exhibit good long-term corrosion inhibition performance at high rotation speeds, and has broad application prospects in the treatment of high-flow oil and gas gathering and transportation pipelines containing CO2 / H2S and high-flow acidic produced water.

Claims

1. An imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end, characterized in that, The corrosion inhibitor has the following structural general formula: ， Among them, R is a straight-chain hydrocarbon group with 10 to 20 carbon atoms.

2. A preparation method of an imidazoline corrosion inhibitor with multiple nitrogen atoms in the adsorption end according to claim 1, characterized in that, The preparation method steps are as follows: (1) Anhydrous piperazine reacts with acrylic acid to form 1,4-bis(2-carboxyethyl)piperazine; (2) 1,4-bis(2-carboxyethyl)piperazine and diethylenetriamine undergo amidation and cyclization reactions to form piperazine gemini imidazoline; (3) Under the action of an acid-binding agent, piperazine gemini imidazoline and long-chain halogenated hydrocarbons undergo N-alkylation reaction to obtain an imidazoline corrosion inhibitor with multiple nitrogen atoms at the adsorption end; The long-chain halogenated hydrocarbons are: decyl bromide, dodecyl bromide, tetradecyl bromide, hexadecyl bromide, decyl chloride, dodecyl chloride, tetradecyl chloride, hexadecyl chloride.

3. The preparation method of the imidazoline corrosion inhibitor with multiple nitrogen atoms in the adsorption end according to claim 2, characterized in that, In step (1), the molar ratio of acrylic acid to anhydrous piperazine is 2 to 2.5:

1.

4. The preparation method of the imidazoline corrosion inhibitor with multiple nitrogen atoms in the adsorption end according to claim 2, characterized in that, In step (2), the molar ratio of diethylenetriamine to 1,4-bis(2-carboxyethyl)piperazine is 2 to 3:1, the reaction temperature is 140 to 230 °C, and the reaction time is 6 to 12 h.

5. The preparation method of the imidazoline corrosion inhibitor with multiple nitrogen atoms in the adsorption end according to claim 2, characterized in that, In step (3), the molar ratio of long-chain halogenated hydrocarbon to piperazine gemini imidazoline is 1 to 1.5:1; the reaction temperature is 60 to 100 °C, and the reaction time is 1 to 3 h.

6. The preparation method of the imidazoline corrosion inhibitor with multiple nitrogen atoms in the adsorption end according to claim 2, characterized in that, In step (3), the acid-binding agent is: triethylamine, pyridine, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate.

7. Use of an imidazoline corrosion inhibitor having multiple nitrogen atoms at the adsorption end according to claim 1, characterized in that, The corrosion inhibitor is applied in the treatment process of high-flow oil and gas gathering and transportation pipelines containing CO2 / HS and acidic produced water.

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