Corrosion inhibitor for oxidation corrosion resistance and preparation method thereof

Abstract

The invention relates to a corrosion inhibitor for oxygen corrosion resistance and a preparation method thereof, and belongs to the field of oilfield chemistry. The corrosion inhibitor comprises the following components in percentage by mass: 30%-50% of D-erythorbic acid didodecyl benzoate, 5%-10% of a surfactant, 5%-10% of a corrosion inhibition synergist, 10%-20% of a cosolvent and 10%-40% of water. The use temperature of the corrosion inhibitor in the working condition ranges from 20 DEG C to 120 DEG C, the corrosion inhibitor is suitable for water-containing oil casing corrosion under the condition that the oxygen pressure ranges from 0.01 MPa to 1.0 MPa, the corrosion inhibitor has the advantages of being small in dosage, small in corrosion rate, easy to implement and the like, and the problems of oil casing corrosion perforation, failure and the like under the existence of the oxygen pressure are effectively relieved.

Description

Technical Field

[0001] The invention belongs to the field of oilfield chemistry, and particularly relates to a corrosion inhibitor for resisting oxygen corrosion and a preparation method thereof. Background Art

[0002] With the advancement of tertiary oil recovery technology, technologies such as nitrogen injection flooding, oxygen-reduced air flooding and original combustion have been applied. With the improvement of crude oil recovery rate, O 2 The corrosion problem has gradually become prominent. At the same time, with the increase of temperature or the increase of mineralization of produced water, the oil casing in the wellbore has been seriously corroded. 2 Corrosion and dissolution will cause perforation, and reduce the thickness of the oil pipe wall, resulting in stress concentration and subsequent fracture. During water injection, dissolved oxygen will cause corrosion and perforation of the pipe column. During air injection, air foam injection and in-situ combustion, a high-temperature and high-pressure oxygen corrosion environment is formed, which seriously threatens the service safety of the pipe column. In the annular protection fluid environment, as the temperature rises, oxygen corrosion to the oil casing is significantly aggravated. The oxygen corrosion problem in different development methods should not be underestimated.

[0003] As a major anti-corrosion method, corrosion inhibitors are highly efficient, convenient, easy to operate, and low cost, and are widely used in oil and gas well production. At present, common corrosion inhibitors are mainly imidazoline, quaternary ammonium salts, and Mannich bases. 2 , H 2 S or both coexist in the environment with significant anti-corrosion effect, but for the environment containing O 2 working conditions, there are disadvantages such as poor corrosion inhibition effect and poor temperature resistance, and it is difficult to achieve O 2 Effective corrosion protection under working conditions. Summary of the invention

[0004] In view of the above problems, the present invention provides a corrosion inhibitor for anti-oxidative corrosion and a preparation method thereof.

[0005] The first object of the present invention is to provide an anti-oxidative corrosion inhibitor, which comprises, by mass percentage, 30% to 50% of D-isoascorbic acid didodecyl benzoate, 5% to 10% of a surfactant, 5% to 10% of a corrosion inhibitor synergist, 10% to 20% of a cosolvent and 10% to 40% of water.

[0006] In a specific embodiment of the present invention, the surfactant is a mixture of any of alkyl glycosides, alcohol ether glycosides, fatty acid methyl ester ethoxylates, coconut oil fatty acid diethanolamide, alkylphenol polyoxyethylene ethers, and nonylphenol polyoxyethylene ethers.

[0007] In a specific embodiment of the present invention, the corrosion inhibitor and synergist is a mixture of any of thiourea, dipropylene disulfide, sodium p-toluenesulfonate, and diethyl phosphate.

[0008] In a specific embodiment of the present invention, the co-solvent is a mixture of any of methanol, ethanol, isopropanol and ethanethiol.

[0009] The second object of the present invention is to provide a method for preparing an anti-oxidative corrosion inhibitor, comprising:

[0010] 30% to 50% of D-isoascorbic acid didodecyl benzoate, 5% to 10% of a surfactant, 5% to 10% of a corrosion inhibitor, 10% to 20% of a cosolvent and 10% to 40% of water are stirred uniformly at room temperature to obtain a corrosion inhibitor for anti-oxidative corrosion.

[0011] In a specific embodiment of the present invention, the preparation method of D-isoascorbic acid didodecyl benzoate comprises the following steps:

[0012] After mixing the sulfuric acid solution and D-isoascorbic acid, stir until D-isoascorbic acid is completely dissolved, and heat to the first reaction temperature, slowly add dodecylbenzoic acid, react for 16-24 hours, continue to heat to the second reaction temperature, react for 8-10 hours, and terminate the reaction. The reaction product is extracted, washed, and dried to obtain D-isoascorbic acid didodecyl benzoate.

[0013] In a specific embodiment of the present invention, the mass fraction of the sulfuric acid solution is 98%.

[0014] In a specific embodiment of the present invention, the mass ratio of sulfuric acid to D-isoascorbic acid in the sulfuric acid solution is 12-15:1.

[0015] In a specific embodiment of the present invention, the molar ratio of the dodecylbenzoic acid to the D-isoascorbic acid is 1:2.5-3.

[0016] In a specific embodiment of the present invention, the first reaction temperature is 20-30°C.

[0017] In a specific embodiment of the present invention, the second reaction temperature is 60-70°C.

[0018] In a specific embodiment of the present invention, the reaction product is extracted, washed, and dried, and the specific operations are as follows:

[0019] Using a mixed solution of ice water and ethyl acetate as an extractant, slowly adding the reaction product into a 0-3°C extractant for extraction 2-5 times, and combining the organic phases, wherein the mass ratio of ice water to ethyl acetate is 10:1-3;

[0020] The organic phase was washed with saturated NaCl solution and anhydrous MgSO 4The mixture was dried, and the solvent was removed by rotary evaporation until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo to obtain white granular crystals, which were D-isoascorbic acid didodecyl benzoate.

[0021] Beneficial effects of the present invention:

[0022] First, D-isoascorbic acid didodecyl benzoate and corrosion inhibitors have good synergistic effects. D-isoascorbic acid didodecyl benzoate has good spreadability on the surface of steel sheets. The benzene ring and five-membered ring in the molecular structure can be tightly combined with the surface of steel sheets. The oxygen elements and double bonds contained can form coordination bonds with Fe atoms, which strengthen the adsorption and temperature resistance of D-isoascorbic acid didodecyl benzoate on the surface of steel sheets. The carbon chain in the D-isoascorbic acid didodecyl benzoate molecule can effectively prevent the contact between the corrosive medium and the surface of the steel sheet. The nucleophilic elements O and N in the corrosion inhibitor are easily adsorbed on the surface of the steel sheet, which supplements the density of the protective film and thus slows down the corrosion.

[0023] Second, the corrosion inhibitor provided by the present invention has an operating temperature of 20°C to 120°C in working conditions, and is suitable for corrosion of water-containing oil casing under oxygen pressure between 0.01-1.0MPa. It has the advantages of small addition amount, low corrosion rate and simple operation, and effectively alleviates the problems of corrosion perforation and failure of oil casing under oxygen pressure.

[0024] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 The preparation route of D-isoascorbic acid didodecyl benzoate in an anti-oxidative corrosion inhibitor according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0028] An anti-oxidative corrosion inhibitor according to an embodiment of the present invention includes, by mass percentage, 30% to 50% D-isoascorbic acid didodecyl benzoate, 5% to 10% surfactant, 5% to 10% corrosion inhibitor synergist, 10% to 20% cosolvent and 10% to 40% water.

[0029] In an embodiment of the present invention, the surfactant is a mixture of any of alkyl glycosides, alcohol ether glycosides, fatty acid methyl ester ethoxylates, coconut oil fatty acid diethanolamide, alkylphenol polyoxyethylene ethers, and nonylphenol polyoxyethylene ethers.

[0030] In the embodiment of the present invention, the corrosion inhibitor and synergist is a mixture of any several of thiourea, dipropylene disulfide, sodium p-toluenesulfonate, and diethyl phosphate.

[0031] In an embodiment of the present invention, the co-solvent is a mixture of any of methanol, ethanol, isopropanol, and ethanethiol.

[0032] A method for preparing an anti-oxidative corrosion inhibitor according to an embodiment of the present invention comprises:

[0033] 30% to 50% of D-isoascorbic acid didodecyl benzoate, 5% to 10% of a surfactant, 5% to 10% of a corrosion inhibitor, 10% to 20% of a cosolvent and 10% to 40% of water are stirred uniformly at room temperature to obtain a corrosion inhibitor for anti-oxidative corrosion.

[0034] In the embodiment of the present invention, the preparation route of D-isoascorbic acid didodecyl benzoate is as follows Figure 1 As shown, including:

[0035] After mixing the sulfuric acid solution and D-isoascorbic acid, stir until D-isoascorbic acid is completely dissolved, and heat to the first reaction temperature, slowly add dodecylbenzoic acid, react for 16-24 hours, continue to heat to the second reaction temperature, react for 8-10 hours, and terminate the reaction. The reaction product is extracted, washed, and dried to obtain D-isoascorbic acid didodecyl benzoate.

[0036] In the embodiment of the present invention, the mass fraction of the sulfuric acid solution is 98%.

[0037] In an embodiment of the present invention, the mass ratio of sulfuric acid to D-isoascorbic acid in the sulfuric acid solution is 12-15:1.

[0038] In an embodiment of the present invention, the molar ratio of the dodecylbenzoic acid to the D-isoascorbic acid is 1:2.5-3.

[0039] In an embodiment of the present invention, the first reaction temperature is 20-30°C, and the specific number of the first reaction temperature is any one of 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C.

[0040] In an embodiment of the present invention, the second reaction temperature is 60-70°C, and the first reaction temperature is any one of 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, and 70°C.

[0041] In the embodiment of the present invention, the reaction product is extracted, washed, and dried, and the specific operations are as follows:

[0042] Using a mixed solution of ice water and ethyl acetate as an extractant, slowly adding the reaction product into a 0-3°C extractant for extraction 2-5 times, and combining the organic phases, wherein the mass ratio of ice water to ethyl acetate is 10:1-3;

[0043] The organic phase was washed with saturated NaCl solution and anhydrous MgSO 4 The mixture was dried, and the solvent was removed by rotary evaporation until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo to obtain white granular crystals, which were D-isoascorbic acid didodecyl benzoate.

[0044] Example 1

[0045] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0046] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 The D-isoascorbic acid (mass ratio is 12:1) is stirred to completely dissolve the D-isoascorbic acid, the temperature is raised to 25°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid is 1:2.5) is slowly added, the reaction is carried out at 20°C for 24 hours, and the reaction is terminated.

[0047] Step 2: Continue to raise the temperature to 60°C for 10 hours, and the reaction is completed.

[0048] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0049] Step 4: Take materials according to the following mass percentage components: 30% D-isoascorbic acid didodecyl benzoate, 5% surfactant, 10% corrosion inhibitor, 20% solvent, 35% water, wherein the surfactant is alkyl glycoside, the corrosion inhibitor is thiourea, and the solvent is methanol.

[0050] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0051] The corrosion inhibitor obtained above was subjected to a corrosion test at 20° C., an oxygen partial pressure of 0.01 MPa, and an inhibitor dosage of 50 mg / L.

[0052] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.045 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0053] Example 2

[0054] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0055] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 The D-isoascorbic acid (mass ratio is 12:1) is stirred to completely dissolve the D-isoascorbic acid, the temperature is raised to 20°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid is 1:2.5) is slowly added, the reaction is carried out at 25°C for 22 hours, and the reaction is terminated.

[0056] Step 2: Continue to raise the temperature to 65°C for 10 hours, and the reaction is completed.

[0057] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0058] Step 4: Take materials according to the following mass percentage components: 35% D-isoascorbic acid didodecyl benzoate, 10% surfactant, 5% corrosion inhibitor, 20% solvent, 30% water, wherein the surfactant is alcohol ether glycoside, the corrosion inhibitor is dipropylene disulfide, and the solvent is isopropanol.

[0059] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0060] The above-obtained anti-oxidative corrosion inhibitor was subjected to a corrosion test at 20°C, an oxygen partial pressure of 0.1 MPa, and an inhibitor dosage of 100 mg / L;

[0061] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.055 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0062] Example 3

[0063] Follow these steps to use a corrosion inhibitor to prevent oxygen corrosion:

[0064] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 The D-isoascorbic acid (mass ratio is 12:1) is stirred to completely dissolve the D-isoascorbic acid, the temperature is raised to 20-30°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid is 1:2.5) is slowly added, the reaction is carried out at 30°C for 16 hours, and the reaction is terminated.

[0065] Step 2: Continue to raise the temperature to 65°C for 8 hours, and the reaction is completed.

[0066] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0067] Step 4: taking materials according to the following mass percentage components: 35% D-isoascorbic acid didodecyl benzoate, 7.5% surfactant, 10% corrosion inhibitor, 20% solvent, 27.5% water; wherein the surfactant is fatty acid methyl ester ethoxylate; the corrosion inhibitor is sodium p-toluenesulfonate; the solvent is ethanethiol;

[0068] Step 5: Stir the above raw materials at room temperature to obtain an anti-oxidative corrosion inhibitor.

[0069] The corrosion inhibitor obtained above was subjected to a corrosion test at 20° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 100 mg / L.

[0070] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.052 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0071] Example 4

[0072] Follow these steps to use a corrosion inhibitor to prevent oxygen corrosion:

[0073] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 D-isoascorbic acid (mass ratio of 12:1) was stirred to completely dissolve D-isoascorbic acid, the temperature was raised to 27°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid was 1:2.5) was slowly added, the reaction was carried out at 30°C for 16 hours, and the reaction was terminated.

[0074] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0075] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0076] Step 4: Take materials according to the following mass percentage components: 40% D-isoascorbic acid didodecyl benzoate, 8% surfactant, 8% corrosion inhibitor, 15% solvent, 29% water, wherein the surfactant is coconut oil fatty acid diethanolamide; the corrosion inhibitor is diethyl phosphate; and the solvent is isopropanol.

[0077] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0078] The corrosion inhibitor obtained above was subjected to a corrosion test at 40° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 100 mg / L.

[0079] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.049 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0080] Example 5

[0081] Follow these steps to use a corrosion inhibitor to prevent oxygen corrosion:

[0082] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 The D-isoascorbic acid (mass ratio is 12:1) is stirred to completely dissolve the D-isoascorbic acid, the temperature is raised to 30°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid is 1:2.5) is slowly added, the reaction is carried out at 30°C for 16 hours, and the reaction is terminated.

[0083] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0084] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0085] Step 4: Take materials according to the following mass percentage components: 40% D-isoascorbic acid didodecyl benzoate, 8% surfactant, 10% corrosion inhibitor, 15% solvent, 27% water, wherein the surfactant is alkylphenol polyoxyethylene ether; the corrosion inhibitor is diethyl phosphate; and the solvent is ethanol.

[0086] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0087] The corrosion inhibitor obtained above was subjected to a corrosion test at 60° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 150 mg / L.

[0088] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.044 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0089] Example 6

[0090] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0091] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 The D-isoascorbic acid (mass ratio is 12:1) is stirred to completely dissolve the D-isoascorbic acid, the temperature is raised to 20°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid is 1:2.5) is slowly added, the reaction is carried out at 30°C for 16 hours, and the reaction is terminated.

[0092] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0093] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0094] Step 4: Take materials according to the following mass percentage components: 45% D-isoascorbic acid didodecyl benzoate, 10% surfactant, 7% corrosion inhibitor, 18% solvent, 20% water, wherein the surfactant is nonylphenol polyoxyethylene ether; the corrosion inhibitor is diethyl phosphate; and the solvent is ethyl mercaptan.

[0095] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0096] The corrosion inhibitor obtained above was subjected to a corrosion test at 80° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 250 mg / L.

[0097] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.059 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0098] Example 7

[0099] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0100] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4D-isoascorbic acid (mass ratio of 12:1) was stirred to completely dissolve D-isoascorbic acid, the temperature was raised to 26°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid was 1:2.5) was slowly added, the reaction was carried out at 30°C for 16 hours, and the reaction was terminated.

[0101] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0102] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0103] Step 4: Take materials according to the following mass percentage components: 50% D-isoascorbic acid didodecyl benzoate, 10% surfactant, 7% corrosion inhibitor, 18% solvent, 15% water, wherein the surfactant is fatty acid methyl ester ethoxylate; the corrosion inhibitor is dipropylene disulfide; the solvent is ethanol.

[0104] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0105] The corrosion inhibitor obtained above was subjected to a corrosion test at 100° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 350 mg / L.

[0106] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.062 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0107] Example 8

[0108] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0109] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 D-isoascorbic acid (mass ratio of 12:1) was stirred to completely dissolve D-isoascorbic acid, the temperature was raised to 20-30°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid was 1:2.5) was slowly added, the reaction was carried out at 30°C for 16 hours, and the reaction was terminated.

[0110] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0111] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4 The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0112] Step 4: Take materials according to the following mass percentage components: 50% D-isoascorbic acid didodecyl benzoate, 10% surfactant, 10% corrosion inhibitor, 20% solvent, 10% water, wherein the surfactant is alkylphenol polyoxyethylene ether; the corrosion inhibitor is sodium p-toluenesulfonate; and the solvent is methanol.

[0113] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0114] The corrosion inhibitor obtained above was subjected to a corrosion test at 120° C., an oxygen partial pressure of 1.0 MPa, and an inhibitor dosage of 500 mg / L.

[0115] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.069 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0116] Example 9

[0117] Prepare the corrosion inhibitor for anti-oxidative corrosion according to the following steps:

[0118] Step 1: Use concentrated H 2 SO 4 (mass fraction 98%) as solvent and catalyst, concentrated H 2 SO 4 D-isoascorbic acid (mass ratio of 12:1) was stirred to completely dissolve D-isoascorbic acid, the temperature was raised to 20-30°C, dodecylbenzoic acid (molar ratio to D-isoascorbic acid was 1:2.5) was slowly added, the reaction was carried out at 30°C for 16 hours, and the reaction was terminated.

[0119] Step 2: Continue to raise the temperature to 70°C for 8 hours, and the reaction is completed.

[0120] Step 3: Using a mixed solution of ice water and ethyl acetate (mass ratio of 10:3) as the extractant, the reaction product was slowly added to the low-temperature extractant for extraction three times, the organic phases were combined, washed with saturated NaCl solution, anhydrous MgSO 4The mixture was dried, and evaporated to remove the solvent at 30°C / 0.1Pa until crystals were precipitated. The mixture was recrystallized with anhydrous ethanol and dried in vacuo at 30°C for 1 h to obtain white granular crystals.

[0121] Step 4: Take materials according to the following mass percentage components: 50% D-isoascorbic acid didodecyl benzoate, 10% surfactant, 10% corrosion inhibitor, 20% solvent, 10% water, wherein the surfactant is fatty acid methyl ester ethoxylate; the corrosion inhibitor is sodium p-toluenesulfonate; and the solvent is ethanethiol.

[0122] Step 5: Stir the raw materials of each component at room temperature to obtain a corrosion inhibitor for anti-oxidation corrosion.

[0123] The corrosion inhibitor obtained above was subjected to a corrosion test at 120° C., an oxygen partial pressure of 0.01 MPa, and an inhibitor dosage of 500 mg / L.

[0124] The corrosion inhibitor of this formula has good water solubility in the test medium, a corrosion rate of 0.034 mm / a, and no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has obvious anti-corrosion effect.

[0125] Comparative Example 1:

[0126] Corrosion inhibitor preparation:

[0127] Step 1: Take materials according to the following mass percentage components: 5% surfactant, 10% corrosion inhibitor, 20% cosolvent, 65% water, wherein the surfactant is alkyl glycoside, the corrosion inhibitor is thiourea, and the cosolvent is methanol.

[0128] Step 2: Stir all the raw materials at room temperature to obtain an anti-oxidative corrosion inhibitor.

[0129] The corrosion inhibitor obtained above was subjected to a corrosion test at 20° C., an oxygen partial pressure of 0.01 MPa, and an inhibitor dosage of 50 mg / L.

[0130] The corrosion inhibitor of this formula has good water solubility in the test medium, but the corrosion rate is 0.47 mm / a, and there is no pitting and pitting. The corrosion inhibitor for anti-oxidative corrosion obtained in this embodiment has poor anti-corrosion effect.

[0131] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A corrosion inhibitor for antioxidant corrosion, characterized in that, by mass percentage, it includes: 30% - 50% D-isoascorbic acid dodecyl benzoate, 5% - 10% surfactant, 5% - 10% corrosion inhibition synergist, 10% - 20% cosolvent, and 10% - 40% water.

2. The corrosion inhibitor for antioxidant corrosion according to claim 1, characterized in that, the surfactant is a mixture of any several of alkyl polyglycoside, alcohol ether glycoside, fatty acid methyl ester ethoxylate, coconut oil fatty acid diethanolamide, alkylphenol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

3. The corrosion inhibitor for antioxidant corrosion according to claim 1, characterized in that, the corrosion inhibition synergist is a mixture of any several of thiourea, diallyl disulfide, sodium p-toluenesulfonate, and diethyl phosphate.

4. The corrosion inhibitor for antioxidant corrosion according to any one of claims 1 - 3, characterized in that, the cosolvent is a mixture of any several of methanol, ethanol, isopropanol, and ethanethiol.

5. A preparation method of a corrosion inhibitor for antioxidant corrosion, characterized in that, it includes: Mix 30% - 50% D-isoascorbic acid dodecyl benzoate, 5% - 10% surfactant, 5% - 10% corrosion inhibition synergist, 10% - 20% cosolvent, and 10% - 40% water evenly by full stirring at normal temperature to obtain the corrosion inhibitor for antioxidant corrosion.

6. The preparation method of a corrosion inhibitor for antioxidant corrosion according to claim 5, characterized in that, the preparation method of the D-isoascorbic acid dodecyl benzoate includes the following steps: After mixing sulfuric acid solution with D-isoascorbic acid, stir until D-isoascorbic acid is completely dissolved, and heat up to the first reaction temperature, slowly add dodecyl benzoic acid, react for 16 - 24 h, continue to heat up to the second reaction temperature, react for 8 - 10 h, after the reaction ends, the reaction product is extracted, washed, and dried to obtain D-isoascorbic acid dodecyl benzoate.

7. The preparation method of a corrosion inhibitor for antioxidant corrosion according to claim 6, characterized in that, the mass fraction of the sulfuric acid solution is 98%.

8. The preparation method of a corrosion inhibitor for antioxidant corrosion according to claim 6, characterized in that, the mass ratio of sulfuric acid to D-isoascorbic acid in the sulfuric acid solution is 12 - 15:

1.

9. The corrosion inhibitor for antioxidant corrosion according to claim 6, characterized in that, the molar ratio of dodecyl benzoic acid to D-isoascorbic acid is 1:2.5 - 3.

10. The preparation method of a corrosion inhibitor for antioxidant corrosion according to claim 6, characterized in that, the first reaction temperature is 20 - 30 °C.

11. The preparation method of a corrosion inhibitor for antioxidant corrosion according to claim 6, characterized in that, the second reaction temperature is 60 - 70 °C.

12. The preparation method of a corrosion inhibitor for antioxidant corrosion according to any one of claims 6 - 11, characterized in that, the specific operations of the extraction, washing, and drying of the reaction product are as follows: Using a mixed solution of ice water and ethyl acetate as the extractant, slowly add the reaction product to the extractant at 0 - 3°C for extraction 2 - 5 times, and combine the organic phases. Among them, the mass ratio of ice water to ethyl acetate is 10:1 - 3; The organic phase was washed with saturated NaCl solution and dried over anhydrous MgSO 4 4. It was concentrated by rotary evaporation until crystals precipitated, recrystallized with absolute ethanol, and dried under vacuum to obtain white granular crystals, which were D-dodecylbenzoate of isovitamin C.

Images