A compound, a preparation method thereof and an inhibitor containing the same

Abstract

The application provides a compound, a preparation method thereof and an inhibitor containing the compound. The compound is obtained by the reaction of 3-acetylpyridine, o-phenylenediamine and 3-bromopyridine, and the structural formula is shown as I. The inhibitor comprises the compound, a surfactant and solvent oil. The inhibitor provided by the application is low in toxicity, friendly to the environment, excellent in corrosion inhibition effect and stable and durable. Under the conditions of 5 MPa of carbon dioxide gas partial pressure, 1 MPa of hydrogen sulfide gas partial pressure and 80 DEG C, the initial corrosion inhibition efficiency of 30 mg / L of the inhibitor reaches more than 95%. The inhibitor is mixed with kerosene with a closed flash point of 85 DEG C at a mass ratio of 1:1, and the corrosion inhibitor film formed on the surface of a 20# carbon steel electrode can stably play a corrosion inhibition role for more than 125 h.

Description

Technical Field

[0001] This invention belongs to the field of corrosion protection technology for oilfield gathering and transportation pipelines, and particularly relates to a compound, its preparation method, and a corrosion inhibitor containing the compound. Background Technology

[0002] During oilfield production, acidic gases such as H2S, CO2, and water are produced alongside natural gas. While dry gases are generally not corrosive, their dissolution in water promotes various forms of electrochemical corrosion in steel. H2S and CO2, present as associated gases in oil and gas, are often introduced into gathering and transportation systems through oil and gas extraction and transportation. Currently, most oil and gas pipelines and other equipment used in oil and gas fields both domestically and internationally are made of carbon steel, materials with generally poor corrosion resistance. Therefore, corrosion problems exist at every stage of oil and gas extraction and transportation. Corrosion of oil and gas extraction, storage, and transportation equipment not only affects production and causes economic losses but also seriously threatens the safety of oil and gas fields. Currently, corrosion inhibitors used in H2S and CO2 corrosive environments have poor solubility, high toxicity, and often have unsatisfactory corrosion inhibition effects, low inhibition efficiency, and cannot provide long-lasting and stable protection. Summary of the Invention

[0003] To address the problems of poor solubility, high toxicity, often unsatisfactory corrosion inhibition effect, low corrosion inhibition efficiency, and inability to provide long-lasting and stable protection in current corrosion inhibitors used in H2S and CO2 environments, this invention provides a compound, its preparation method, and a corrosion inhibitor containing the compound. The compound exhibits good corrosion inhibition effect and stable and durable corrosion inhibition; the corrosion inhibitor containing the compound has low toxicity, is environmentally friendly, and provides excellent and stable corrosion inhibition effect.

[0004] One aspect of the present invention provides a compound having the structural formula shown in Formula I.

[0005]

[0006] The second invention provides a method for preparing the compound as described in the first invention, comprising the following steps:

[0007] 1) Mix 3-acetylpyridine and o-phenylenediamine, react to obtain a mixture containing the first intermediate;

[0008] 2) The mixture containing the first intermediate is mixed with 3-bromopyridine and reacted to obtain a mixture containing the second intermediate;

[0009] 3) React the mixture containing the second intermediate in an acidic environment to obtain a crude product containing the compound.

[0010] In one specific embodiment, the total mass of the 3-acetylpyridine, o-phenylenediamine, and 3-bromopyridine is 100%, the amount of the 3-acetylpyridine is 29 wt% to 33 wt%, the amount of the o-phenylenediamine is 26 wt% to 29 wt%, and the amount of the 3-bromopyridine is 38 wt% to 45 wt%.

[0011] In one specific embodiment, in step 1), a first catalyst is used to carry out the catalytic reaction; and / or

[0012] In step 2), a second catalyst is used to carry out the catalytic reaction;

[0013] Preferably, the total mass of the 3-acetylpyridine and o-phenylenediamine is 100%, and the amount of the first catalyst is 3 wt% to 8 wt%.

[0014] Preferably, the mass of the 3-bromopyridine is 100%, and the amount of the second catalyst is 4 wt% to 10 wt%.

[0015] Preferably, the first catalyst is acetone;

[0016] Preferably, the second catalyst is methanol.

[0017] In one specific embodiment, in step 1), the 3-acetylpyridine is heated to 50°C to 90°C and then mixed with the o-phenylenediamine; and / or

[0018] The reaction conditions in step 1) are 90°C to 160°C for 3 to 10 hours; and / or

[0019] The mixing and reaction in step 2) are carried out in an anaerobic environment; and / or

[0020] The reaction temperature in step 2) is 30°C to 70°C and / or the reaction duration is 3h to 6h;

[0021] Preferably, nitrogen gas is introduced in step 2) to remove oxygen and create an oxygen-free environment.

[0022] In one specific embodiment, the reaction conditions in step 3) are as follows: the mixture containing the second intermediate is mixed with sulfuric acid and reacted at 30°C to 70°C for 30 min to 60 min, or the mixture containing the second intermediate is mixed with sodium bisulfite and reacted at 100°C to 120°C for 1 h to 1.5 h.

[0023] Preferably, each 100g of 3-acetylpyridine corresponds to 0.1mol to 0.15mol of the sulfuric acid or the sodium bisulfite.

[0024] In one specific embodiment, step 1) further includes eluting the reaction product with a first eluent after the reaction to obtain the mixture containing the first intermediate; and / or

[0025] The mixture containing the second intermediate obtained in step 2) can be used directly in step 3) without purification;

[0026] The crude product containing the compound in step 3) is eluted with a second eluent to obtain the compound.

[0027] Preferably, the first eluent and the second eluent independently comprise 8 to 10 parts by weight of petroleum ether and 1 part by weight of triethylamine.

[0028] The third invention provides a corrosion inhibitor comprising a compound and a surfactant;

[0029] The compound is either the compound described in one of the present inventions or the compound prepared by the method described in another of the present inventions.

[0030] In one specific embodiment, the corrosion inhibitor comprises 2 to 3 parts by weight of the compound and 1 to 2 parts by weight of the surfactant.

[0031] In one specific embodiment, the surfactant is at least one of amphoteric surfactants, cationic surfactants, anionic surfactants, and nonionic surfactants;

[0032] Preferably, the zwitterionic surfactant is at least one selected from dodecyl dimethyl hydroxypropyl sulfonyl betaine, dodecyl dimethyl sulfonyl betaine, cocamidopropyl betaine, and octadecyl ethoxy sulfonyl betaine.

[0033] Preferably, the cationic surfactant is docosyltrimethylammonium chloride;

[0034] Preferably, the anionic surfactant is sodium lauroyl amino acid and / or sodium dodecylbenzenesulfonate;

[0035] Preferably, the nonionic surfactant is cetearyl glucoside.

[0036] In one specific embodiment, the corrosion inhibitor further includes solvent oil;

[0037] Preferably, the total mass ratio of the compound and surfactant to the solvent oil is 1:(1 to 1.2);

[0038] Preferably, the closed-cup flash point of the solvent oil is not lower than 85°C;

[0039] Preferably, the solvent oil is kerosene with a closed-cup flash point of 85°C to 100°C.

[0040] The application of at least one of the compounds described in one of the present inventions, the compounds prepared by the method described in another of the present inventions, and the corrosion inhibitors described in a third of the present invention in the corrosion protection of oilfield gathering and transportation pipelines, particularly as corrosion inhibitors against H2S / CO2 corrosion in oilfield gathering and transportation pipelines.

[0041] The beneficial effects of this invention are:

[0042] To address the problems of poor solubility, high toxicity, unsatisfactory corrosion inhibition effect, and inability to provide long-lasting and stable protection in existing corrosion inhibitors used in H2S and CO2 corrosive environments, this invention provides a compound, its preparation method, and a corrosion inhibitor containing the compound. The compound exhibits excellent corrosion inhibition effect and stable corrosion inhibition. Under conditions of 5 MPa partial pressure of carbon dioxide gas, 1 MPa partial pressure of hydrogen sulfide gas, and 80°C, the initial corrosion inhibition efficiency of 30 mg / L of the compound can reach 82%, and the corrosion inhibition efficiency can reach 75% after 3 days. When the compound is further mixed with kerosene at a mass ratio of 1:1 and a closed-cup flash point of 85°C, the corrosion inhibitor film formed on the surface of a 20# carbon steel electrode can stably exert its corrosion inhibition effect for up to 101 hours. The corrosion inhibitor formulated from the aforementioned compound, surfactant, and solvent oil exhibits low toxicity, environmental friendliness, and excellent, stable, and long-lasting corrosion inhibition performance. Under conditions of 5 MPa partial pressure of carbon dioxide, 1 MPa partial pressure of hydrogen sulfide, and 80°C, the initial corrosion inhibition efficiency of 30 mg / L of the inhibitor can reach over 95%, and the corrosion inhibition efficiency can reach over 92% after 3 days. Further mixing the inhibitor with kerosene (closed-cup flash point 85°C) at a 1:1 mass ratio results in a corrosion inhibitor film formed on the surface of a 20# carbon steel electrode that can stably exert its corrosion inhibition effect for over 125 hours. The preparation method of the compound is simple, using few and readily available raw materials, and the preparation conditions are easy to achieve, making it suitable for widespread application. Detailed Implementation

[0043] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0044] Preparation of compounds

[0045] Example 1

[0046] The compound was prepared according to the following method:

[0047] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 60°C, add 89.10g of o-phenylenediamine and 14g of acetone, using acetone as a catalyst, rapidly heat to 100°C, react for 9h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0048] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, remove oxygen by purging with nitrogen, add 6g of methanol as a catalyst, continue to heat to 60℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 3h to obtain a mixture containing the second intermediate.

[0049] 3) Add 0.1 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 60 °C for 30 min to obtain crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 72.66%.

[0050] Example 2

[0051] The compound was prepared according to the following method:

[0052] 1) Place 95g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 70°C, add 84.64g of o-phenylenediamine and 8g of acetone, using acetone as a catalyst, rapidly heat to 110°C, react for 10h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0053] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, remove oxygen by purging with nitrogen, add 10g of methanol as a catalyst, continue to heat to 70℃ under nitrogen protection, add 135g of 3-bromopyridine, react for 4h to obtain a mixture containing the second intermediate.

[0054] 3) Add 0.12 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 70 °C for 30 min to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 84.53%.

[0055] Example 3

[0056] The compound was prepared according to the following method:

[0057] 1) Place 109g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 50°C, add 97.12g of o-phenylenediamine and 10g of acetone, using acetone as a catalyst, rapidly heat to 90°C, react for 10h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0058] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 10g of methanol as a catalyst, continue to heat to 50℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 4h to obtain a mixture containing the second intermediate.

[0059] 3) Add 0.1 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 50 °C for 40 min to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 77.76%.

[0060] Example 4

[0061] The compound was prepared according to the following method:

[0062] 1) Place 92g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 90°C, add 81.97g of o-phenylenediamine and 6g of acetone, using acetone as a catalyst, rapidly heat to 150°C, react for 5h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0063] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, remove oxygen by purging with nitrogen, add 12g of methanol as a catalyst, continue to heat to 40℃ under nitrogen protection, add 140g of 3-bromopyridine, react for 5h to obtain a mixture containing the second intermediate.

[0064] 3) Add 0.1 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 40 °C for 30 min to obtain crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 87.23%.

[0065] Example 5

[0066] The compound was prepared according to the following method:

[0067] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 70°C, add 89.10g of o-phenylenediamine and 12g of acetone, using acetone as a catalyst, rapidly heat to 150°C, react for 4h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0068] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 10g of methanol as a catalyst, continue to heat to 40℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 6h to obtain a mixture containing the second intermediate.

[0069] 3) Add 0.15 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 30 °C for 60 min to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 81.74%.

[0070] Example 6

[0071] The compound was prepared according to the following method:

[0072] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 90°C, add 89.10g of o-phenylenediamine and 14g of acetone, using acetone as a catalyst, rapidly heat to 120°C, react for 3h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0073] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 10g of methanol as a catalyst, continue to heat to 40℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 4h to obtain a mixture containing the second intermediate.

[0074] 3) Add 0.15 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 40 °C for 30 min to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 85.91%.

[0075] Example 7

[0076] The compound was prepared according to the following method:

[0077] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 80°C, add 89.10g of o-phenylenediamine and 10g of acetone, using acetone as a catalyst, rapidly heat to 140°C, react for 5h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0078] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 10g of methanol as a catalyst, continue to heat to 60℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 4h to obtain a mixture containing the second intermediate.

[0079] 3) Add 0.1 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at 60 °C for 30 min to obtain crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 78.75%.

[0080] Example 8

[0081] The compound was prepared according to the following method:

[0082] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 60°C, add 89.10g of o-phenylenediamine and 8g of acetone, using acetone as a catalyst, rapidly heat to 160°C, react for 7h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0083] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 13g of methanol as a catalyst, continue to heat to 30°C under nitrogen protection, add 130g of 3-bromopyridine, react for 3h to obtain a mixture containing the second intermediate.

[0084] 3) Add 0.15 mol NaHSO3 to the mixture containing the second intermediate obtained in step 2), react at 100 °C for 90 min to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 82.99%.

[0085] Example 9

[0086] The compound was prepared according to the following method:

[0087] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 50°C, add 89.10g of o-phenylenediamine and 12g of acetone, using acetone as a catalyst, rapidly heat to 130°C, react for 3h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0088] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, remove oxygen by purging with nitrogen, add 8g of methanol as a catalyst, continue to heat to 30℃ under nitrogen protection, add 130g of 3-bromopyridine, react for 6h to obtain a mixture containing the second intermediate.

[0089] 3) Add 0.1 mol NaHSO3 to the mixture containing the second intermediate obtained in step 2), react at 120 °C for 1 h to obtain the crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 75.81%.

[0090] Preparation of corrosion inhibitors

[0091] Example 10

[0092] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 40g of cocamidopropyl betaine in 165g of kerosene with a closed-cup flash point of 85°C, mix well, and obtain corrosion inhibitor 1.

[0093] Example 11

[0094] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 50g of docosyltrimethylammonium chloride in 180g of kerosene with a closed-cup flash point of 90°C, mix well, and obtain corrosion inhibitor 2.

[0095] Example 12

[0096] 100g of the compound prepared in any one of Examples 1 to 9 and 40g of sodium lauroyl amide were dissolved in 140g of kerosene with a closed-cup flash point of 100°C and mixed evenly to obtain corrosion inhibitor 3.

[0097] Example 13

[0098] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 50g of sodium dodecylbenzenesulfonate in 150g of kerosene with a closed-cup flash point of 90°C, mix well, and obtain corrosion inhibitor 4.

[0099] Example 14

[0100] Dissolve 90g of the compound prepared in any one of Examples 1 to 9 and 60g of sodium dodecylbenzenesulfonate in 165g of kerosene with a closed-cup flash point of 85°C, mix well, and obtain corrosion inhibitor 5.

[0101] Example 15

[0102] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 50g of cetearyl glucoside in 160g of kerosene with a closed-cup flash point of 90°C, mix well, and obtain corrosion inhibitor 6.

[0103] Example 16

[0104] Dissolve 90g of the compound prepared in any one of Examples 1 to 9 and 50g of dodecyl dimethyl hydroxypropyl sulfobetaine in 140g of kerosene with a closed-cup flash point of 100°C, mix well, and obtain corrosion inhibitor 7.

[0105] Example 17

[0106] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 50g of dodecyl dimethyl sulfopropyl betaine in 160g of kerosene with a closed-cup flash point of 100°C, mix well, and obtain corrosion inhibitor 8.

[0107] Example 18

[0108] Dissolve 100g of the compound prepared in any one of Examples 1 to 9 and 50g of octadecylethoxysulfonylbetaine in 160g of kerosene with a closed-cup flash point of 100°C, mix well, and obtain corrosion inhibitor 9.

[0109] Comparative Example 1

[0110] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 30°C, add 89.10g of o-phenylenediamine and 2g of acetone, using acetone as a catalyst, rapidly heat to 80°C, react for 2h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0111] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 5g of methanol as a catalyst, continue to cool to room temperature under nitrogen protection, add 130g of 3-bromopyridine, react for 2h to obtain a mixture containing the second intermediate.

[0112] 3) Add 0.1 mol H2SO4 to the mixture containing the second intermediate obtained in step 2), react at room temperature for 30 min to obtain crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 35.27%.

[0113] Comparative Example 2

[0114] 1) Place 100g of 3-acetylpyridine in a three-necked flask, reflux with a condenser, heat to 110°C, add 89.10g of o-phenylenediamine and 20g of acetone, using acetone as a catalyst, rapidly heat to 200°C, react for 2h, cool to room temperature, and elute with a mixture of petroleum ether and triethylamine in a mass ratio of 10:1 to obtain a mixture containing the first intermediate;

[0115] 2) Place the mixture containing the first intermediate obtained in step 1) into a three-necked flask, reflux it with a condenser, purge with nitrogen to remove oxygen, add 25g of methanol as a catalyst, continue to cool to room temperature under nitrogen protection, add 130g of 3-bromopyridine, react for 2h to obtain a mixture containing the second intermediate.

[0116] 3) Add 0.2 mol NaHSO3 to the mixture containing the second intermediate obtained in step 2), react at room temperature for 2 h to obtain crude product, elute with a mixture of petroleum ether and triethylamine in a mass ratio of 8:1 to obtain the compound with the structural formula as shown in Formula I, with a yield of 51.47%.

[0117] Comparative Example 3

[0118] 100g of the compound prepared in Comparative Example 1 and 30g of cocamidopropyl betaine were dissolved in 130g of kerosene with a closed-cup flash point of 85℃ and mixed evenly to obtain corrosion inhibitor 10.

[0119] Comparative Example 4

[0120] 100g of the compound prepared in Comparative Example 2 and 30g of cocamidopropyl betaine were dissolved in 130g of kerosene with a closed-cup flash point of 85℃ and mixed evenly to obtain corrosion inhibitor 11.

[0121] Experimental Evaluation

[0122] 1. Evaluation of the corrosion inhibition effect of corrosion inhibitors

[0123] The initial corrosion inhibition efficiency, corrosion inhibition efficiency after 3 days, and corrosion inhibition efficiency after 7 days were determined for compounds prepared in any one of Examples 1 to 9 (taking the compound prepared in Example 1 as an example), compounds prepared in Comparative Examples 1 and 2, corrosion inhibitors 1 to 9 prepared in Examples 10 to 18, corrosion inhibitor 10 prepared in Comparative Examples 3 and 4, and corrosion inhibitor 11, under the conditions of 80°C, a partial pressure of carbon dioxide gas of 5 MPa, and a partial pressure of hydrogen sulfide gas of 1 MPa. The specific test methods are as follows:

[0124] 1) Preparation of simulated solution: Dissolve NaCl, CaCl2, Na2SO4, MgCl2, NaHCO3 and KCl in water to obtain a simulated solution. The mass concentrations of various inorganic salts in the simulated solution are as follows: 33.89 g / L NaCl, 80.239 g / L CaCl2, 0.6656 g / L Na2SO4, 1.571 g / L MgCl2, 1.515 g / L NaHCO3 and 0.308 g / L KCl;

[0125] 2) Method for determining corrosion inhibition efficiency:

[0126] i. Take a 20# carbon steel hanging piece (hereinafter referred to as the hanging piece) and measure its weight and dimensions using a precision balance and vernier calipers;

[0127] ii. Add the simulated solution prepared in step 1) to the autoclave, and purge with nitrogen to remove dissolved oxygen. Maintain the autoclave temperature at 80°C from the start of the experiment until the end of the experiment. Add a compound or corrosion inhibitor to the simulated solution to achieve a concentration of 30 mg / L, obtaining the experimental group solution. No compound or corrosion inhibitor is added to the blank group; the simulated solution after removing dissolved oxygen is used as the blank group solution.

[0128] iii. A mixture of carbon dioxide and hydrogen sulfide gas was introduced into the autoclave containing the experimental group solution and the autoclave containing the blank group solution, respectively, so that the total pressure in each autoclave was 15 MPa, of which the partial pressure of carbon dioxide gas was 5 MPa and the partial pressure of hydrogen sulfide gas was 1 MPa.

[0129] iv. Three tablets were immersed in each of the experimental group solution and the blank group solution to form three parallel experiments. After the experiment started, carbon dioxide and hydrogen sulfide gas were continuously introduced into each autoclave to maintain the total pressure in each autoclave as well as the partial pressure of carbon dioxide gas and the partial pressure of hydrogen sulfide gas in step iii.

[0130] v. At three time points of 1h, 72h and 168h, the plates after corrosion in the experimental group solution and the blank group solution were taken out. The corrosion products on the plates were removed by chemical cleaning using a film removal solution obtained by dissolving 10g of hexamethylenetetramine and 100mL of concentrated hydrochloric acid in 900mL of deionized water. The plates were cleaned with anhydrous ethanol, dried with nitrogen gas and weighed with a precision balance. The corrosion rate of each plate was calculated by formula (1), and the average corrosion rate of the three plates in the same group was further calculated. The corrosion inhibition efficiency was then calculated by combining formula (2).

[0131]

[0132] In equation (1), CR is the corrosion rate;

[0133] w1 represents the initial mass of the coupon before corrosion.

[0134] w2 represents the mass of the plate after corrosion.

[0135] S is the area of ​​the hanging piece;

[0136] ρ is the density of the material used for the hanging piece;

[0137] t represents the experimental time.

[0138]

[0139] In equation (2), η is the corrosion inhibition efficiency;

[0140] v0 represents the average corrosion rate of the blank group;

[0141] v1 represents the average corrosion rate of the experimental group.

[0142] The specific results are shown in Table 1.

[0143] Table 1. Corrosion inhibition efficiency of compounds and corrosion inhibitors

[0144]

[0145] As shown in Table 1, the initial corrosion inhibition efficiency, corrosion inhibition efficiency after 3 days, and corrosion inhibition efficiency after 7 days of the compound prepared in Example 1 were significantly higher than those of the compounds prepared in Comparative Examples 1 and 2. The reason for this is that the reaction conditions, such as reaction temperature and reaction time, changed during the preparation of the compounds in Comparative Examples 1 and 2, leading to a significant decrease in the yield of the compounds. Even after eluting the crude product with a mixture of petroleum ether and triethylamine at a mass ratio of 8:1, the resulting compound still contained a large number of impurities, causing an overall decrease in its initial corrosion inhibition efficiency, corrosion inhibition efficiency after 3 days, and corrosion inhibition efficiency after 7 days. The compounds prepared in Examples 10 to 18... The initial corrosion inhibition efficiency of the corrosion inhibitors was generally high, all above 95%. After 3 days, the corrosion inhibition efficiency was all above 92%, and after 7 days, the corrosion inhibition efficiency was still above 89%. Among them, the corrosion inhibitor prepared in Example 12 achieved an initial corrosion inhibition efficiency of 98.6%, and the corrosion inhibitor prepared in Example 16 achieved a corrosion inhibition efficiency of 96.6% after 3 days and a slow-release efficiency of 93.5% after 7 days, demonstrating excellent corrosion inhibition effects. The corrosion inhibitors prepared in Comparative Examples 3 and 4 had poor corrosion inhibition effects. The reason for this was that the compounds used in Comparative Examples 3 and 4 were compounds containing a large number of impurities, which ultimately affected the overall corrosion inhibition effect of the corrosion inhibitors.

[0146] 2. Evaluation of the corrosion inhibition stability and durability of compounds and corrosion inhibitors

[0147] The corrosion inhibition stability and durability of compounds and corrosion inhibitors can be evaluated by measuring film durability. The LPR (linear polarization resistance) electrochemical method was used to measure the film durability of compounds prepared in any one of Examples 1 to 9 (using the compound prepared in Example 1 as an example), compounds prepared in Comparative Examples 1 and 2, corrosion inhibitors 1 to 9 prepared in Examples 10 to 18, and corrosion inhibitors 10 and 11 prepared in Comparative Examples 3 and 4, under conditions of 80°C, a partial pressure of carbon dioxide gas of 5 MPa, and a partial pressure of hydrogen sulfide gas of 1 MPa. The specific methods are as follows:

[0148] 1) Experimental apparatus: potentiostat, a three-electrode system using a 20# carbon steel electrode as the working electrode, a platinum electrode as the auxiliary electrode, and a saturated calomel electrode as the reference electrode;

[0149] 2) Sample preparation: Polish the working area of ​​the 20# carbon steel electrode with 2000# sandpaper until it is shiny, wipe it with acetone to remove oil, wash it with distilled water, and blow it dry with a hair dryer, leaving 1cm. 2 The remaining area is sealed with wax (using transparent tape or epoxy resin adhesive) as the working area.

[0150] 3) Pre-film treatment of sample surface: Dissolve 2.5g of compound or corrosion inhibitor in 2.5g of kerosene with a closed flash point of 85℃ to obtain pre-film treatment solution. Immerse the 20# carbon steel electrode treated in step 2) in the pre-film treatment solution for 20min to obtain the 20# carbon steel electrode after pre-film treatment.

[0151] 4) Preparation of simulated solution: Same as step 1) in Experiment 1;

[0152] 5) Add the simulated solution prepared in step 4) into the autoclave, and purge with nitrogen to remove dissolved oxygen. The temperature in the autoclave is 80℃ from the time the simulated solution is added until the end of the experiment.

[0153] 6) A mixture of carbon dioxide and hydrogen sulfide gas is introduced into the autoclave containing the deoxygenated simulated solution in 5) so that the total pressure in the autoclave is 15 MPa, wherein the partial pressure of carbon dioxide gas is 5 MPa and the partial pressure of hydrogen sulfide gas is 1 MPa.

[0154] 7) Immerse the 20# carbon steel electrode after pre-filming treatment in step 3) into the deoxygenated simulated solution obtained in step 6) by introducing carbon dioxide and hydrogen sulfide gas, connect the three-electrode system, and start the experiment. During the experiment, continuously introduce carbon dioxide and hydrogen sulfide gas into the autoclave to maintain the total pressure in the autoclave as described in step 6) as well as the partial pressure of carbon dioxide gas and the partial pressure of hydrogen sulfide gas.

[0155] 8) Use a potentiostat to measure the polarization curve of the 20# carbon steel electrode during the experiment in step 7), and use the corrosion analysis software CorrWareCorrView system to calculate the corrosion current. Finally, calculate the corrosion rate of the 20# carbon steel electrode.

[0156] 9) The longest time the corrosion inhibitor film remained intact was determined by the point at which the corrosion rate suddenly increased significantly. The test results are shown in Table 2.

[0157] Table 2. Film Durability of Compounds and Corrosion Inhibitors

[0158]

[0159] As shown in Table 2, the compound prepared in Example 1, after being further compounded with kerosene with a closed-cup flash point of 85°C at a mass ratio of 1:1, formed a corrosion inhibitor film on a 20# carbon steel electrode with good durability and a duration of up to 101.3 hours. However, the compounds prepared in Comparative Examples 1 and 2, due to changes in reaction temperature and time during preparation, resulted in low yields and high impurity content, leading to poor durability and a shorter duration of the corrosion inhibitor film formed on the 20# carbon steel electrode after further compounding with kerosene with a closed-cup flash point of 85°C at a mass ratio of 1:1. The corrosion inhibitors prepared in Examples 10 to 18 exhibited good corrosion inhibition stability and durability. In Example 16, the corrosion inhibitor prepared and kerosene with a closed-cup flash point of 85°C were further compounded at a mass ratio of 1:1. The corrosion inhibitor film formed on the 20# carbon steel electrode exhibited the best durability, lasting up to 136.5 hours, demonstrating excellent corrosion inhibition stability and durability. In contrast, the corrosion inhibitors prepared in Comparative Examples 3 and 4, after being further compounded with kerosene with a closed-cup flash point of 85°C at a mass ratio of 1:1, did not achieve a duration of 100 hours for the corrosion inhibitor film formed on the 20# carbon steel electrode, which was far shorter than that in Examples 10 to 18. This indicates that the compounds used in the corrosion inhibitors prepared in Comparative Examples 3 and 4, which had too low a yield and contained a large number of impurities, affected the duration of the corrosion inhibitor film.

[0160] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. A corrosion inhibitor comprising a compound with the structure shown in Formula I and a surfactant; Formula I; The corrosion inhibitor comprises 2 to 3 parts by weight of the compound and 1 to 2 parts by weight of the surfactant; The surfactant is at least one of zwitterionic surfactants, cationic surfactants, anionic surfactants and nonionic surfactants; The zwitterionic surfactant is at least one of dodecyl dimethyl hydroxypropyl sulfobetaine, dodecyl dimethyl sulfopropyl betaine, cocamidopropyl betaine, and octadecyl ethoxy sulfobetaine. The cationic surfactant is docosyltrimethylammonium chloride; The anionic surfactant is sodium lauroyl amino acid and / or sodium dodecylbenzenesulfonate; The nonionic surfactant is cetearyl glucoside.

2. The corrosion inhibitor according to claim 1, characterized in that, The corrosion inhibitor also includes solvent oil.

3. The corrosion inhibitor according to claim 2, characterized in that, The total mass ratio of the compound and surfactant to the solvent oil is 1:(1 to 1.2).

4. The corrosion inhibitor according to claim 2 or 3, characterized in that, The closed-cup flash point of the solvent oil is not lower than 85°C.

5. The corrosion inhibitor according to claim 2 or 3, characterized in that, The solvent oil is kerosene.

6. The application of the corrosion inhibitor according to any one of claims 1 to 5 or the compound of claim 1 with the structure shown in Formula I as a corrosion inhibitor for H2S / CO2 corrosion in oilfield gathering and transportation pipelines.

Images