Preparation process of ionic liquid corrosion inhibitor for oil field

Abstract

The invention relates to the technical field of corrosion inhibitors, in particular to a preparation process of an ionic liquid corrosion inhibitor for oil fields, which comprises the following raw materials in percentage by weight: 12-14% of corrosion inhibition loaded ionic liquid, 18-22% of scale inhibition loaded ionic liquid, 10-15% of surfactant, 3-5% of ethylene glycol and the balance of water. Meanwhile, the ionic liquid is loaded on the calcium-based montmorillonite and the composite hydroxyapatite, so that the corrosion and scale inhibition capacity of the corrosion inhibitor is further improved, and meanwhile, the problem that the release of the ionic liquid corrosion inhibitor in an oil field is uncontrollable is avoided; therefore, the ionic liquid corrosion inhibitor can effectively exert good corrosion and scale inhibition capability.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion inhibitors, and in particular to a preparation process of an ionic liquid corrosion inhibitor for oil fields. Background Art

[0002] During the exploitation and transportation of oil and gas fields, metal pipelines and equipment are exposed to high temperature, high pressure, high mineralization and complex environments containing corrosive media for a long time, which makes them very prone to electrochemical corrosion, pitting corrosion and stress corrosion cracking, resulting in shortened equipment life, increased safety hazards and increased operation and maintenance costs. Therefore, corrosion inhibitors are needed to prevent the corrosion of metal pipelines. Ionic liquid corrosion inhibitors have good and efficient corrosion inhibition properties, and have low interference with other chemical additives used in oil fields, which makes them widely concerned. However, most ionic liquids are difficult to biodegrade in the natural environment, and because the corrosion inhibition behavior of ionic liquids is highly dependent on their own spontaneous adsorption, the corrosion inhibition behavior of ionic liquids is uncontrollable, which may lead to local corrosion inhibition failure or excessive consumption, and cannot meet the gradually increasing market demand. Summary of the invention

[0003] The purpose of the present invention is to provide a preparation process of an ionic liquid corrosion inhibitor for oil fields. By preparing a degradable ionic liquid, the ionic liquid has a certain degradation ability, and is loaded on calcium-based montmorillonite and composite hydroxyapatite, which not only further improves the corrosion and scale inhibition ability of the corrosion inhibitor, but also avoids the problem of uncontrollable release of the ionic liquid corrosion inhibitor in the oil field, so that the ionic liquid corrosion inhibitor can effectively exert good corrosion and scale inhibition ability.

[0004] The purpose of the present invention can be achieved through the following technical scheme: a preparation process of an ionic liquid corrosion inhibitor for oil fields, which comprises the following steps: weighing the following raw materials in weight percentage: 12-14% corrosion inhibition loaded ionic liquid, 18-22% scale inhibition loaded ionic liquid, 10-15% surfactant and 3-5% ethylene glycol, the remainder being water, mixing the corrosion inhibition loaded ionic liquid, scale inhibition loaded ionic liquid, surfactant, ethylene glycol and water to prepare an ionic liquid corrosion inhibitor for oil fields.

[0005] The corrosion-inhibiting loaded ionic liquid is prepared by the following steps:

[0006] The calcium-based montmorillonite and deionized water are mixed and ultrasonically dispersed for 30-40 minutes to obtain a montmorillonite suspension system, the degradable ionic liquid and the methanol solution are mixed and added to the montmorillonite suspension system, stirred at a stirring rate of 180-240 rpm and a temperature of 25-30° C. for 12 hours, centrifuged, and dried to obtain a corrosion-inhibiting ionic liquid;

[0007] The mass fraction of the methanol solution is 30%, and the amount ratio of calcium-based montmorillonite, deionized water, degradable ionic liquid and methanol solution is 0.8-1.2g:180-200mL:1.8-1.9g:30-35mL;

[0008] The calcium-based montmorillonite is Aohong 120 mesh calcium-based montmorillonite;

[0009] During the reaction, the calcium-based montmorillonite is firstly stripped by ultrasound, and then the cations in the degradable ionic liquid are exchanged between the montmorillonite layers by an ion exchange method to obtain a corrosion-inhibiting ionic liquid.

[0010] The scale-inhibiting loaded ionic liquid is prepared by the following steps:

[0011] Step A1: cetyltrimethylammonium bromide, diammonium hydrogen phosphate and deionized water are mixed, ammonia solution is added to adjust the pH value to 10, calcium chloride solution is added after stirring, and then the mixture is reacted for 24 hours at a stirring rate of 120-140 rpm and a temperature of 115-120° C. in a reactor, centrifuged, washed with water, dried, ground, and then calcined for 3-3.5 hours at a temperature of 600° C. to obtain mesoporous hydroxyapatite; mesoporous hydroxyapatite is mixed with N,N-dimethylformamide, zirconium chloride and terephthalic acid are added after stirring at a stirring rate of 240-300 rpm and a temperature of 25-30° C., and the mixture is stirred for 30-35 minutes, and then the mixture is reacted for 24 hours at a stirring rate of 120-140 rpm and a temperature of 115-120° C. in a reactor, centrifuged, washed, and dried to obtain composite hydroxyapatite;

[0012] The molar concentration of the calcium chloride solution is 0.19 mol / L, the mass fraction of the ammonia solution is 25%, the dosage ratio of hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate, deionized water and calcium chloride solution is 0.3-0.31 g: 0.44-0.45 g: 30-35 mL: 28-31 mL; the dosage ratio of mesoporous hydroxyapatite, N,N-dimethylformamide, zirconium chloride and terephthalic acid is 0.1-0.12 g: 55-60 mL: 2.3-2.4 g: 1.6-1.7 g;

[0013] In the reaction process, hexadecyltrimethylammonium bromide is used as a soft template to form hydroxyapatite with a mesoporous structure through a hydrothermal method, and then through the coordination of zirconium ions with carboxyl groups in terephthalic acid through a hydrothermal method, a metal organic framework structure is formed on the surface of the mesoporous hydroxyapatite to obtain a composite hydroxyapatite.

[0014] Step A2: Mix composite hydroxyapatite, acetonitrile and N,N-dimethylformamide, stir and add degradable ionic liquid at a stirring rate of 240-300 rpm and a temperature of 45° C., react for 24 hours, wash, filter and dry to obtain a scale-inhibiting loaded ionic liquid;

[0015] The usage ratio of composite hydroxyapatite, acetonitrile, N,N-dimethylformamide and degradable ionic liquid is 0.24-0.28 g: 19-21 mL: 1.5-2 mL: 0.35-0.38 g;

[0016] During the reaction, the degradable ionic liquid is loaded in the composite hydroxyapatite by an impregnation method to obtain the scale-inhibiting loaded ionic liquid.

[0017] The degradable ionic liquid is prepared by the following steps:

[0018] Step B1: mix terephthalaldehyde and malononitrile, grind for 30-35 minutes, put into a microwave oven to react for 35 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes 8-10 times, stop the reaction to obtain intermediate a, mix intermediate a, pentaerythritol and N,N-dimethylformamide, stir at a stirring rate of 140-160 rpm and a temperature of 90-95°C, stir and add p-toluenesulfonic acid, react for 4-4.5 hours, wash with water, filter and dry to obtain intermediate b;

[0019] The dosage ratio of terephthalaldehyde and malononitrile is 1.32-1.38 g: 0.65-0.68 g; the dosage ratio of intermediate a, pentaerythritol, N,N-dimethylformamide and p-toluenesulfonic acid is 1.80-1.85 g: 0.65-0.7 g: 60-65 mL: 0.08-0.1 g;

[0020] During the reaction, the aldehyde group in terephthalaldehyde reacts with malononitrile through a grinding microwave method to form a single protection structure to obtain intermediate a, and the aldehyde group in intermediate a then reacts with the hydroxyl group in pentaerythritol to form a spiro ring structure to obtain intermediate b;

[0021] Step B2: Mix the intermediate b and sodium hydroxide solution, grind for 15-20 minutes, put into a microwave oven to react for 30 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes 5-6 times, wash with water, filter and dry to obtain intermediate c, mix intermediate c, o-phenylenediamine, sodium metabisulfite, ethanol and deionized water, react for 10-12 hours at a stirring rate of 180-240 rpm and a temperature of 93-95°C, wash with water, filter and dry to obtain intermediate d;

[0022] The mass fraction of the sodium hydroxide solution is 10%, the dosage ratio of the intermediate b and the sodium hydroxide solution is 1.15-1.18 g: 5-8 mL; the dosage ratio of the intermediate c, o-phenylenediamine, sodium pyrosulfite, ethanol and deionized water is 1.88-1.95 g: 3.2-3.25 g: 4.5-5 g: 50-55 mL: 5-10 mL;

[0023] During the reaction, the intermediate b reacts with a sodium hydroxide solution by a grinding microwave method, deprotects to form an aldehyde group, and obtains an intermediate c. Then, under the action of sodium pyrosulfite, the intermediate c reacts with o-phenylenediamine to form a benzimidazole structure, and obtains an intermediate d.

[0024] Step B3: Mix the intermediate d, iodoethane and toluene, react for 20-24 hours at a stirring rate of 140-150 rpm and a temperature of 115-118° C., cool, wash with toluene, and dry to obtain a degradable ionic liquid;

[0025] The ratio of intermediate d, ethyl iodide and toluene is 1.25-1.29 g: 1.55-1.6 g: 60-70 mL;

[0026] During the reaction, the benzimidazole structure in the intermediate d reacts with ethyl iodide to form a benzimidazolium salt structure to obtain a degradable ionic liquid.

[0027] Beneficial effects of the invention: The invention discloses a preparation process of an ionic liquid corrosion inhibitor for oil fields. By preparing a degradable ionic liquid, the ionic liquid has a certain degradation ability, and the ionic liquid is loaded on calcium-based montmorillonite and composite hydroxyapatite, which not only further improves the corrosion and scale inhibition ability of the corrosion inhibitor, but also avoids the problem of uncontrollable release of the ionic liquid corrosion inhibitor in the oil field, so that the ionic liquid corrosion inhibitor can effectively exert good corrosion and scale inhibition ability; because the degradable ionic liquid contains a spirocyclic group, the presence of the spirocyclic group makes the ionic liquid have a certain degradation ability, and at the same time, due to its own benzimidazolium structure, it After being loaded on composite hydroxyapatite, it can play a complex role with hydroxyapatite to exert better corrosion and scale inhibition capabilities. The mesoporous hydroxyapatite in the composite hydroxyapatite and the metal-organic framework structure generated on its surface enable the composite hydroxyapatite to better load degradable ionic liquids. The existence of its special structure enables it to play a controlled release role, thereby avoiding the problem of local corrosion inhibition failure or excessive consumption. Since the corrosion-inhibiting loaded ionic liquid itself is based on calcium-based montmorillonite, this layered loading also enables it to better form a protective film on the metal surface to avoid corrosion of the metal surface by corrosive media. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1 A preparation process of an ionic liquid corrosion inhibitor for oil fields, which comprises the following steps: weigh the following raw materials in weight percentage: 12% corrosion inhibition loaded ionic liquid, 18% scale inhibition loaded ionic liquid, 10% surfactant and 3% ethylene glycol, the remainder being water, mixing the corrosion inhibition loaded ionic liquid, scale inhibition loaded ionic liquid, surfactant, ethylene glycol and water to prepare an ionic liquid corrosion inhibitor for oil fields.

[0030] The corrosion-inhibiting loaded ionic liquid is prepared by the following steps:

[0031] The calcium-based montmorillonite and deionized water were mixed and ultrasonically dispersed for 30 minutes to obtain a montmorillonite suspension system, the degradable ionic liquid and the methanol solution were mixed and added to the montmorillonite suspension system, stirred at a stirring rate of 180 rpm and a temperature of 25°C for 12 hours, centrifuged, and dried to obtain a corrosion-inhibiting ionic liquid;

[0032] The mass fraction of the methanol solution is 30%, and the amount ratio of calcium-based montmorillonite, deionized water, degradable ionic liquid and methanol solution is 0.8g:180mL:1.8g:30mL;

[0033] The calcium-based montmorillonite is Aohong 120 mesh calcium-based montmorillonite;

[0034] The scale-inhibiting loaded ionic liquid is prepared by the following steps:

[0035] Step A1: cetyltrimethylammonium bromide, diammonium hydrogen phosphate and deionized water are mixed, ammonia solution is added to adjust the pH value to 10, calcium chloride solution is added after stirring, and then the mixture is reacted for 24 hours at a stirring rate of 120 rpm and a temperature of 115° C. in a reactor, centrifuged, washed with water, dried, ground, and then calcined for 3 hours at a temperature of 600° C. to obtain mesoporous hydroxyapatite, mesoporous hydroxyapatite is mixed with N,N-dimethylformamide, zirconium chloride and terephthalic acid are added after stirring at a stirring rate of 240 rpm and a temperature of 25° C., and the mixture is stirred for 30 minutes, and then the mixture is reacted for 24 hours at a stirring rate of 120 rpm and a temperature of 115° C. in a reactor, centrifuged, washed, and dried to obtain composite hydroxyapatite;

[0036] The molar concentration of calcium chloride solution is 0.19 mol / L, the mass fraction of ammonia solution is 25%, the dosage ratio of hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate, deionized water and calcium chloride solution is 0.3 g: 0.44 g: 30 mL: 28 mL; the dosage ratio of mesoporous hydroxyapatite, N, N-dimethylformamide, zirconium chloride and terephthalic acid is 0.1 g: 55 mL: 2.3 g: 1.6 g;

[0037] Step A2: composite hydroxyapatite, acetonitrile and N,N-dimethylformamide are mixed, stirred at a stirring rate of 240 rpm and a temperature of 45° C., and a degradable ionic liquid is added, reacted for 24 hours, washed, filtered and dried to obtain a scale-inhibiting loaded ionic liquid;

[0038] The usage ratio of composite hydroxyapatite, acetonitrile, N,N-dimethylformamide and degradable ionic liquid is 0.24 g: 19 mL: 1.5 mL: 0.35 g;

[0039] The degradable ionic liquid is prepared by the following steps:

[0040] Step B1: terephthalaldehyde and malononitrile were mixed, ground for 35 minutes, placed in a microwave oven for reaction for 35 seconds, taken out and ground for 5 minutes, and the microwave reaction for 35 seconds and grinding for 5 minutes were repeated 8 times, and the reaction was stopped to obtain intermediate a. Intermediate a, pentaerythritol and N,N-dimethylformamide were mixed, stirred at a stirring rate of 160 rpm and a temperature of 90-95°C, and p-toluenesulfonic acid was added, reacted for 4 hours, washed with water, filtered and dried to obtain intermediate b;

[0041] The dosage ratio of terephthalaldehyde and malononitrile is 1.38g:0.65g; the dosage ratio of intermediate a, pentaerythritol, N,N-dimethylformamide and p-toluenesulfonic acid is 1.85g:0.65g:65mL:0.08g;

[0042] Step B2: Mix the intermediate b and sodium hydroxide solution, grind for 20 minutes, put into a microwave oven to react for 30 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes step 5 times, wash with water, filter and dry to obtain the intermediate c, mix the intermediate c, o-phenylenediamine, sodium metabisulfite, ethanol and deionized water, react for 12 hours at a stirring rate of 240 rpm and a temperature of 93°C, wash with water, filter and dry to obtain the intermediate d;

[0043] The mass fraction of sodium hydroxide solution is 10%, the usage ratio of intermediate b and sodium hydroxide solution is 1.15g:8mL; the usage ratio of intermediate c, o-phenylenediamine, sodium pyrosulfite, ethanol and deionized water is 1.88g:3.25g:4.5g:55mL:5mL;

[0044] Step B3: Mix the intermediate d, ethyl iodide and toluene, react for 20 hours at a stirring rate of 140 rpm and a temperature of 118° C., cool, wash with toluene, and dry to obtain a degradable ionic liquid;

[0045] The usage ratio of intermediate d, ethyl iodide and toluene is 1.29 g:1.55 g:60 mL.

[0046] Example 2 A preparation process for an ionic liquid corrosion inhibitor for oil fields, which comprises the following steps: weigh the following raw materials in weight percentage: 14% corrosion inhibition loaded ionic liquid, 18% scale inhibition loaded ionic liquid, 15% surfactant and 3% ethylene glycol, the remainder being water, and mix the corrosion inhibition loaded ionic liquid, scale inhibition loaded ionic liquid, surfactant, ethylene glycol and water to obtain an ionic liquid corrosion inhibitor for oil fields.

[0047] The corrosion-inhibiting loaded ionic liquid is prepared by the following steps:

[0048] The calcium-based montmorillonite and deionized water were mixed and ultrasonically dispersed for 40 minutes to obtain a montmorillonite suspension system, and the degradable ionic liquid and the methanol solution were mixed and added to the montmorillonite suspension system. The mixture was stirred at a stirring rate of 180 rpm and a temperature of 30°C for 12 hours, centrifuged, and dried to obtain a corrosion-inhibiting ionic liquid.

[0049] The mass fraction of the methanol solution is 30%, and the amount ratio of calcium-based montmorillonite, deionized water, degradable ionic liquid and methanol solution is 1.2g:180mL:1.8g:35mL;

[0050] The calcium-based montmorillonite is Aohong 120 mesh calcium-based montmorillonite;

[0051] The scale-inhibiting loaded ionic liquid is prepared by the following steps:

[0052] Step A1: Mix hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate and deionized water, add ammonia solution to adjust the pH value to 10, stir and add calcium chloride solution, and then react in a reactor at a stirring rate of 120 rpm and a temperature of 120° C. for 24 hours, centrifuge, wash with water, dry, grind, and then calcine at a temperature of 600° C. for 3 hours to obtain mesoporous hydroxyapatite, mix mesoporous hydroxyapatite and N,N-dimethylformamide, stir and add zirconium chloride and terephthalic acid at a stirring rate of 300 rpm and a temperature of 25° C., stir for 35 minutes, and then react in a reactor at a stirring rate of 120 rpm and a temperature of 120° C. for 24 hours, centrifuge, wash, and dry to obtain composite hydroxyapatite;

[0053] The molar concentration of calcium chloride solution is 0.19 mol / L, the mass fraction of ammonia solution is 25%, the dosage ratio of hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate, deionized water and calcium chloride solution is 0.3 g: 0.45 g: 30 mL: 31 mL; the dosage ratio of mesoporous hydroxyapatite, N, N-dimethylformamide, zirconium chloride and terephthalic acid is 0.1 g: 60 mL: 2.3 g: 1.6 g;

[0054] Step A2: Mix composite hydroxyapatite, acetonitrile and N,N-dimethylformamide, stir and add degradable ionic liquid at a stirring rate of 300 rpm and a temperature of 45° C., react for 24 hours, wash, filter and dry to obtain a scale-inhibiting loaded ionic liquid;

[0055] The usage ratio of composite hydroxyapatite, acetonitrile, N,N-dimethylformamide and degradable ionic liquid is 0.24 g: 21 mL: 1.5 mL: 0.38 g;

[0056] The degradable ionic liquid is prepared by the following steps:

[0057] Step B1: terephthalaldehyde and malononitrile were mixed, ground for 30 minutes, placed in a microwave oven for reaction for 35 seconds, taken out and ground for 5 minutes, and the microwave reaction for 35 seconds and grinding for 5 minutes were repeated 8 times, and the reaction was stopped to obtain intermediate a. Intermediate a, pentaerythritol and N,N-dimethylformamide were mixed, stirred at a stirring rate of 140 rpm and a temperature of 90°C, and p-toluenesulfonic acid was added, reacted for 4 hours, washed with water, filtered and dried to obtain intermediate b;

[0058] The dosage ratio of terephthalaldehyde and malononitrile is 1.32g:0.65g; the dosage ratio of intermediate a, pentaerythritol, N,N-dimethylformamide and p-toluenesulfonic acid is 1.80g:0.65g:60mL:0.08g;

[0059] Step B2: Mix the intermediate b and sodium hydroxide solution, grind for 15 minutes, put into a microwave oven to react for 30 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes step 5 times, wash with water, filter and dry to obtain intermediate c, mix intermediate c, o-phenylenediamine, sodium metabisulfite, ethanol and deionized water, react for 10 hours at a stirring rate of 180 rpm and a temperature of 93°C, wash with water, filter and dry to obtain intermediate d;

[0060] The mass fraction of sodium hydroxide solution is 10%, the usage ratio of intermediate b and sodium hydroxide solution is 1.15g:5mL; the usage ratio of intermediate c, o-phenylenediamine, sodium pyrosulfite, ethanol and deionized water is 1.88g:3.2g:4.5g:50mL:5mL;

[0061] Step B3: Mix the intermediate d, ethyl iodide and toluene, react for 20 hours at a stirring rate of 140 rpm and a temperature of 115° C., cool, wash with toluene, and dry to obtain a degradable ionic liquid;

[0062] The usage ratio of intermediate d, ethyl iodide and toluene is 1.25 g:1.55 g:60 mL.

[0063] Example 3 A preparation process of an ionic liquid corrosion inhibitor for oil fields, which includes the following steps: weigh the following raw materials in weight percentage: 14% corrosion inhibition loaded ionic liquid, 22% scale inhibition loaded ionic liquid, 15% surfactant and 5% ethylene glycol, the remainder is water, mix the corrosion inhibition loaded ionic liquid, scale inhibition loaded ionic liquid, surfactant, ethylene glycol and water to prepare an ionic liquid corrosion inhibitor for oil fields.

[0064] The corrosion-inhibiting loaded ionic liquid is prepared by the following steps:

[0065] The calcium-based montmorillonite and deionized water were mixed and ultrasonically dispersed for 40 minutes to obtain a montmorillonite suspension system, and the degradable ionic liquid and the methanol solution were mixed and added to the montmorillonite suspension system. The mixture was stirred at a stirring rate of 240 rpm and a temperature of 30° C. for 12 hours, centrifuged, and dried to obtain a corrosion-inhibiting ionic liquid.

[0066] The mass fraction of the methanol solution is 30%, and the amount ratio of calcium-based montmorillonite, deionized water, degradable ionic liquid and methanol solution is 1.2g:200mL:1.9g:35mL;

[0067] The calcium-based montmorillonite is Aohong 120 mesh calcium-based montmorillonite;

[0068] The scale-inhibiting loaded ionic liquid is prepared by the following steps:

[0069] Step A1: cetyltrimethylammonium bromide, diammonium hydrogen phosphate and deionized water are mixed, ammonia solution is added to adjust the pH value to 10, calcium chloride solution is added after stirring, and then the mixture is reacted for 24 hours at a stirring rate of 140 rpm and a temperature of 120° C. in a reactor, centrifuged, washed with water, dried, ground, and then calcined for 3.5 hours at a temperature of 600° C. to obtain mesoporous hydroxyapatite, mesoporous hydroxyapatite is mixed with N,N-dimethylformamide, zirconium chloride and terephthalic acid are added after stirring at a stirring rate of 300 rpm and a temperature of 30° C., and the mixture is stirred for 35 minutes, and then the mixture is reacted for 24 hours at a stirring rate of 140 rpm and a temperature of 120° C. in a reactor, centrifuged, washed, and dried to obtain composite hydroxyapatite;

[0070] The molar concentration of calcium chloride solution is 0.19 mol / L, the mass fraction of ammonia solution is 25%, the dosage ratio of hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate, deionized water and calcium chloride solution is 0.31 g: 0.45 g: 35 mL: 31 mL; the dosage ratio of mesoporous hydroxyapatite, N, N-dimethylformamide, zirconium chloride and terephthalic acid is 0.12 g: 60 mL: 2.4 g: 1.7 g;

[0071] Step A2: Mix composite hydroxyapatite, acetonitrile and N,N-dimethylformamide, stir and add degradable ionic liquid at a stirring rate of 300 rpm and a temperature of 45° C., react for 24 hours, wash, filter and dry to obtain a scale-inhibiting loaded ionic liquid;

[0072] The usage ratio of composite hydroxyapatite, acetonitrile, N,N-dimethylformamide and degradable ionic liquid is 0.28 g: 21 mL: 2 mL: 0.38 g;

[0073] The degradable ionic liquid is prepared by the following steps:

[0074] Step B1: terephthalaldehyde and malononitrile were mixed, ground for 35 minutes, placed in a microwave oven for reaction for 35 seconds, taken out and ground for 5 minutes, and the microwave reaction for 35 seconds and grinding for 5 minutes were repeated 10 times, and the reaction was stopped to obtain intermediate a. Intermediate a, pentaerythritol and N,N-dimethylformamide were mixed, stirred at a stirring rate of 160 rpm and a temperature of 95°C, and p-toluenesulfonic acid was added, reacted for 4.5 hours, washed with water, filtered, and dried to obtain intermediate b;

[0075] The dosage ratio of terephthalaldehyde and malononitrile is 1.38g:0.68g; the dosage ratio of intermediate a, pentaerythritol, N,N-dimethylformamide and p-toluenesulfonic acid is 1.85g:0.7g:65mL:0.1g;

[0076] Step B2: Mix the intermediate b and sodium hydroxide solution, grind for 20 minutes, put into a microwave oven to react for 30 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes step 6 times, wash with water, filter and dry to obtain the intermediate c, mix the intermediate c, o-phenylenediamine, sodium metabisulfite, ethanol and deionized water, react for 12 hours at a stirring rate of 240 rpm and a temperature of 95°C, wash with water, filter and dry to obtain the intermediate d;

[0077] The mass fraction of sodium hydroxide solution is 10%, the usage ratio of intermediate b and sodium hydroxide solution is 1.18g:8mL; the usage ratio of intermediate c, o-phenylenediamine, sodium pyrosulfite, ethanol and deionized water is 1.95g:3.25g:5g:55mL:10mL;

[0078] Step B3: Mix the intermediate d, ethyl iodide and toluene, react for 24 hours at a stirring rate of 150 rpm and a temperature of 118° C., cool, wash with toluene, and dry to obtain a degradable ionic liquid;

[0079] The usage ratio of intermediate d, ethyl iodide and toluene is 1.29 g:1.6 g:70 mL.

[0080] Comparative Example 1 Compared with Example 3, this comparative example replaces the composite hydroxyapatite in the preparation process of the scale-inhibiting loaded ionic liquid in Example 3 with mesoporous nano-silica, and the other steps are the same.

[0081] Comparative Example 2 Compared with Example 3, this comparative example is characterized in that the intermediate d in the preparation process of the degradable ionic liquid in Example 3 is replaced by benzimidazole, and the other steps are the same.

[0082] Take the ionic liquid corrosion inhibitors prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, dry the ionic liquid corrosion inhibitors, and bury them in a plastic container filled with soil, the soil pH = 7, at a temperature of 30 ° C, in the presence of air, and store for 90 days. Calculate the mass residual rate after 90 days, refer to SY / T 5273-2000 "Evaluation Method for Corrosion Inhibitor Performance for Oilfield Produced Water", and perform static and dynamic corrosion rate evaluation. The material of the hanging piece is N80 carbon steel, the temperature is 80 ° C, and the concentration of the ionic liquid corrosion inhibitor is 150 mg / L to evaluate its corrosion resistance. The test results are shown in Table 1 below:

[0083] Table 1 Test results

[0084]

[0085]

[0086] It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1 and Comparative Example 2, Comparative Example 1 replaces the composite hydroxyapatite in the preparation process of the scale-inhibiting loaded ionic liquid in Example 3 with mesoporous nano-silica. Due to the lack of the composite hydroxyapatite structure, its controlled release performance and corrosion and scale inhibition performance are reduced. Comparative Example 2 replaces the intermediate d in the preparation process of the degradable ionic liquid in Example 3 with benzimidazole. Due to the lack of the spirocyclic group, its degradation performance is reduced.

[0087] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0088] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A process for preparing an ionic liquid corrosion inhibitor for oil fields, characterized in that: The method comprises the following steps: weighing the following raw materials in weight percentage: 12-14% of corrosion-inhibiting ionic liquid, 18-22% of scale-inhibiting ionic liquid, 10-15% of surfactant and 3-5% of ethylene glycol, with the balance being water, and mixing the corrosion-inhibiting ionic liquid, scale-inhibiting ionic liquid, surfactant, ethylene glycol and water to prepare an ionic liquid corrosion inhibitor for oil fields; The corrosion-inhibiting loaded ionic liquid is prepared by the following steps: mixing calcium-based montmorillonite and deionized water and ultrasonically dispersing for 30-40 minutes to obtain a montmorillonite suspension system, mixing a degradable ionic liquid and a methanol solution, and adding the mixture to the montmorillonite suspension system, stirring for 12 hours at a stirring rate of 180-240 rpm and a temperature of 25-30° C., centrifuging, and drying to obtain a corrosion-inhibiting ionic liquid; The mass fraction of the methanol solution is 30%, and the dosage ratio of calcium-based montmorillonite, deionized water, degradable ionic liquid and methanol solution is 0.8-1.2g:180-200mL:1.8-1.9g:30-35mL.

2. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 1, characterized in that: The scale-inhibiting loaded ionic liquid is prepared by the following steps: Step A1: cetyltrimethylammonium bromide, diammonium hydrogen phosphate and deionized water are mixed, ammonia solution is added to adjust the pH value to 10, calcium chloride solution is added after stirring, and then the mixture is reacted for 24 hours at a stirring rate of 120-140 rpm and a temperature of 115-120° C. in a reactor, centrifuged, washed with water, dried, ground, and then calcined for 3-3.5 hours at a temperature of 600° C. to obtain mesoporous hydroxyapatite; mesoporous hydroxyapatite is mixed with N,N-dimethylformamide, zirconium chloride and terephthalic acid are added after stirring at a stirring rate of 240-300 rpm and a temperature of 25-30° C., and the mixture is stirred for 30-35 minutes, and then the mixture is reacted for 24 hours at a stirring rate of 120-140 rpm and a temperature of 115-120° C. in a reactor, centrifuged, washed, and dried to obtain composite hydroxyapatite; Step A2: Mix composite hydroxyapatite, acetonitrile and N,N-dimethylformamide, stir and add degradable ionic liquid at a stirring rate of 240-300 rpm and a temperature of 45°C, react for 24 hours, wash, filter and dry to obtain a scale-inhibiting loaded ionic liquid.

3. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 2, characterized in that: In step A1, the molar concentration of the calcium chloride solution is 0.19 mol / L, the mass fraction of the ammonia solution is 25%, the amount ratio of hexadecyltrimethylammonium bromide, diammonium hydrogen phosphate, deionized water and calcium chloride solution is 0.3-0.31 g: 0.44-0.45 g: 30-35 mL: 28-31 mL; the amount ratio of mesoporous hydroxyapatite, N,N-dimethylformamide, zirconium chloride and terephthalic acid is 0.1-0.12 g: 55-60 mL: 2.3-2.4 g: 1.6-1.7 g.

4. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 2, characterized in that: In step A2: the usage ratio of composite hydroxyapatite, acetonitrile, N,N-dimethylformamide and degradable ionic liquid is 0.24-0.28 g: 19-21 mL: 1.5-2 mL: 0.35-0.38 g.

5. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 1, characterized in that: The degradable ionic liquid is prepared by the following steps: Step B1: mix terephthalaldehyde and malononitrile, grind for 30-35 minutes, put into a microwave oven to react for 35 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes 8-10 times, stop the reaction to obtain intermediate a, mix intermediate a, pentaerythritol and N,N-dimethylformamide, stir at a stirring rate of 140-160 rpm and a temperature of 90-95°C, stir and add p-toluenesulfonic acid, react for 4-4.5 hours, wash with water, filter and dry to obtain intermediate b; Step B2: Mix the intermediate b and sodium hydroxide solution, grind for 15-20 minutes, put into a microwave oven to react for 30 seconds, take out and grind for 5 minutes, repeat the microwave reaction for 35 seconds and grinding for 5 minutes 5-6 times, wash with water, filter and dry to obtain intermediate c, mix intermediate c, o-phenylenediamine, sodium metabisulfite, ethanol and deionized water, react for 10-12 hours at a stirring rate of 180-240 rpm and a temperature of 93-95°C, wash with water, filter and dry to obtain intermediate d; Step B3: Mix the intermediate d, iodoethane and toluene, react for 20-24 hours at a stirring rate of 140-150 rpm and a temperature of 115-118° C., cool, wash with toluene, and dry to obtain a degradable ionic liquid.

6. The process for preparing an ionic liquid corrosion inhibitor for oil fields according to claim 5, characterized in that: In step B1, the ratio of terephthalaldehyde to malononitrile is 1.32-1.38 g: 0.65-0.68 g; the ratio of intermediate a, pentaerythritol, N,N-dimethylformamide and p-toluenesulfonic acid is 1.80-1.85 g: 0.65-0.7 g: 60-65 mL: 0.08-0.1 g.

7. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 5, characterized in that: In step B2: the mass fraction of the sodium hydroxide solution is 10%, the amount ratio of the intermediate b and the sodium hydroxide solution is 1.15-1.18 g: 5-8 mL; the amount ratio of the intermediate c, o-phenylenediamine, sodium pyrosulfite, ethanol and deionized water is 1.88-1.95 g: 3.2-3.25 g: 4.5-5 g: 50-55 mL: 5-10 mL.

8. The preparation process of an ionic liquid corrosion inhibitor for oil fields according to claim 5, characterized in that: In step B3: the ratio of intermediate d, iodoethane and toluene is 1.25-1.29 g: 1.55-1.6 g: 60-70 mL.

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