High-temperature-resistant water-soluble Schiff base corrosion inhibitor and preparation method thereof

Abstract

The application discloses a high-temperature-resistant water-soluble Schiff base corrosion inhibitor and a preparation method thereof. The high-temperature-resistant water-soluble Schiff base corrosion inhibitor has the following structural formula: the preparation method of the high-temperature-resistant water-soluble Schiff base corrosion inhibitor comprises the following steps: first, 2,6-pyridine dimethyl formaldehyde is used as raw material to react with organic amine to generate a Schiff base; and finally, quaternary amination reaction is carried out with a chlorohydrocarbon. The high-temperature-resistant water-soluble Schiff base corrosion inhibitor has strong adsorption and good water solubility, and has good corrosion protection effect on carbon steel under the super-high-temperature condition in an organic acid medium environment at > 150 DEG C.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemicals, in particular to a high-temperature-resistant water-soluble Schiff base corrosion inhibitor and a preparation method of the water-soluble Schiff base corrosion inhibitor. BACKGROUND

[0002] With the gradual development of exploration and development to the ultra-deep layer, super-high-temperature reservoirs appear, and the maximum bottom hole temperature reaches above 180 DEG C. In the acidification reconstruction of such super-high-temperature reservoirs, the corrosion risk of acid liquid to downhole string is great, especially in difficult pressure reservoirs, and the performance requirements of acidification corrosion inhibitor are very harsh. Although the existing acidification corrosion inhibitor can meet the acidification medium at 100 DEG C to 150 DEG C high temperature, when the temperature is greater than 150 DEG C, the existing acidification corrosion inhibitor has the disadvantages of poor solubility and dispersibility, easy coking, precipitation, delamination, poor compatibility and the like. SUMMARY

[0003] The present application aims to solve the problems existing in the prior art and provide a high-temperature-resistant water-soluble Schiff base corrosion inhibitor and a preparation method thereof.

[0004] The present application provides a high-temperature-resistant water-soluble Schiff base corrosion inhibitor, which has the structural formula as shown in formula I:

[0005] To achieve the above-mentioned purposes of the present application, the following technical solutions are specifically provided.

[0006] The present application provides a high-temperature-resistant water-soluble Schiff base corrosion inhibitor, which has the structural formula as shown in formula I:

[0007]

[0008] In the formula I, R1, R2 are the same or different, and each, individually or jointly have the following meanings: straight-chain or branched hydrocarbon having 1-20 C atoms, saturated bond-containing or unsaturated bond-containing having 1-20 C atoms, X is one of Cl, Br, I.

[0009] In the high-temperature resistant water-soluble Schiff base corrosion inhibitor, preferably, R1 is -Ph, cycloalkyl, -C 11 H 23 , -C8H 17 , -C 15 H 31 , 2-pyridyl; R2 is propenyl, -Ph, methyl, ethyl, -C 11 H 23 , -C8H 17 , -C 15 H 31 , -CH2CH2COONa, -CH2CH2SO3Na; X is one of Cl, Br, I.

[0010] The application further provides a preparation method of the above-mentioned structure corrosion inhibitor, comprising the following steps:

[0011] (1) using alcohol as a solvent, 2,6-pyridine dimethyl formaldehyde and organic amine are added in a molar ratio of 1:2.00-2.05, an acid is added to adjust the pH to 4-6, and then the mixture is reacted at 60-90°C for 4-6h, and then cooled, filtered and recrystallized to obtain 2,6-pyridyl Schiff base, and the reaction formula is as shown below:

[0012]

[0013] (2) using alcohol as a solvent, the prepared 2,6-pyridyl Schiff base and halogenated hydrocarbon are placed in a reactor in a substance amount ratio of 1:(1.05-1.15), heated and subjected to quaternary amination reaction at 60-90°C for 2-4h, and then the alcohol solvent is evaporated to obtain a water-soluble Schiff base pyridine quaternary ammonium salt corrosion inhibitor, and the reaction formula is as shown below:

[0014]

[0015] In the preparation method of the water-soluble Schiff base corrosion inhibitor, preferably, the reaction temperature in the step 1) is 80-90°C.

[0016] Preferably, the reaction temperature in the step 2) is 60-80°C.

[0017] Preferably, the alcohol solvent is anhydrous ethanol.

[0018] The prepared high-temperature resistant water-soluble Schiff base corrosion inhibitor has a corrosion rate of carbon steel of less than 0.075 mm / a in a sodium formate, sodium citrate or other acidification system at a temperature of greater than 150 DEG C. DETAILED DESCRIPTION

[0019] The technical solutions of the present application are further illustrated by the following examples.

[0020] Example 1

[0021] (1) Under the condition of 25 DEG C, 2,6-pyridine dimethyl formaldehyde, aniline and excessive solvent anhydrous ethanol are added into a reactor, the molar ratio of 2,6-pyridine dimethyl formaldehyde and aniline is 1:2.05, the temperature is increased to 45 DEG C for stirring, after the raw materials are completely dissolved, glacial acetic acid is slowly added dropwise, the pH of the system is adjusted to 5, and then the reaction is carried out at 85 DEG C for 5 hours, and then the temperature is cooled to room temperature, and then the 2,6-pyridine Schiff base is obtained after filtration and recrystallization.

[0022] (2) 2,6-pyridine Schiff base and benzyl chloride are accurately weighed in a reactor with a thermometer, a stirrer, a condenser and a water separator, and then ethanol is added into the reactor as a solvent, the molar ratio of 2,6-pyridine Schiff base and benzyl chloride is 1:1, the mass ratio of 2,6-pyridine Schiff base and ethanol is 1:3, the temperature is increased to 70 DEG C for refluxing for 5 hours, and then the pyridine Schiff base quaternary ammonium salt corrosion inhibitor is obtained.

[0023] Example 2

[0024] (1) Under the condition of 25 DEG C, 2,6-pyridine dimethyl formaldehyde, cyclohexylamine and excessive solvent anhydrous ethanol are added into a reactor, the molar ratio of 2,6-pyridine dimethyl formaldehyde and cyclohexylamine is 1:2.05, the temperature is increased to 50 DEG C for stirring, after the raw materials are completely dissolved, glacial acetic acid is slowly added dropwise, the pH of the system is adjusted to 5, and then the reaction is carried out at 80 DEG C for 6 hours, and then the temperature is cooled to room temperature, and then the 2,6-pyridine Schiff base is obtained after filtration and recrystallization.

[0025] (2) 2,6-pyridine Schiff base and benzyl chloride are accurately weighed in a reactor with a thermometer, a stirrer, a condenser and a water separator, and then ethanol is added into the reactor as a solvent, the molar ratio of 2,6-pyridine Schiff base and benzyl chloride is 1:1, the mass ratio of 2,6-pyridine Schiff base and ethanol is 1:3, the temperature is increased to 80 DEG C for refluxing for 5 hours, and then the pyridine Schiff base quaternary ammonium salt corrosion inhibitor is obtained.

[0026] Example 3

[0027] (1) 25℃, in the reactor, add 2,6-pyridine dimethyl formaldehyde, 2-amino pyridine and excess solvent anhydrous ethanol, the molar ratio of 2,6-pyridine dimethyl formaldehyde and 2-amino pyridine is 1:2.05, warm up to 40℃ stirring, after the raw material is completely dissolved, slowly drop in glacial acetic acid, adjust the pH of the system to 4.5, then react at 70℃ for 5h, cool to room temperature, filter, recrystallize, get 2,6-pyridyl Schiff base.

[0028] (2) in the reactor with thermometer, stirrer, condenser and water separator, accurately weigh 2,6-pyridyl Schiff base and benzyl chloride in turn, at the same time, add anhydrous ethanol as solvent into the reactor, the molar ratio of 2,6-pyridyl Schiff base and benzyl chloride is 1:1, the mass ratio of 2,6-pyridyl Schiff base and ethanol is 1:3, warm up to 80℃, reflux for 4h, get pyridyl Schiff base quaternary ammonium salt corrosion inhibitor.

[0029] Example 4:

[0030] (1) 25℃, in the reactor, add 2,6-pyridine dimethyl formaldehyde, dodecylamine and excess solvent anhydrous ethanol, the molar ratio of 2,6-pyridine dimethyl formaldehyde and dodecylamine is 1:2.05, warm up to 50℃ stirring, after the raw material is completely dissolved, slowly drop in glacial acetic acid, adjust the pH of the system to 6, then react at 80℃ for 6h, cool to room temperature, filter, recrystallize, get 2,6-pyridyl Schiff base.

[0031] (2) in the reactor with thermometer, stirrer, condenser and water separator, accurately weigh 2,6-pyridyl Schiff base and benzyl chloride in turn, at the same time, add anhydrous ethanol as solvent into the reactor, the molar ratio of 2,6-pyridyl Schiff base and benzyl chloride is 1:1, the mass ratio of 2,6-pyridyl Schiff base and ethanol is 1:3, warm up to 80℃, reflux for 6h, get pyridyl Schiff base quaternary ammonium salt corrosion inhibitor.

[0032] Example 5:

[0033] (1) 25℃, in the reactor, add 2,6-pyridine dimethyl formaldehyde, aniline and excess solvent anhydrous ethanol, the molar ratio of 2,6-pyridine dimethyl formaldehyde and aniline is 1:2.05, warm up to 45℃ stirring, after the raw material is completely dissolved, slowly drop in glacial acetic acid, adjust the pH of the system to 4.5, then react at 85℃ for 5h, cool to room temperature, filter, recrystallize, get 2,6-pyridyl Schiff base.

[0034] (2) into the reactor with thermometer, stirrer, condenser and water separator, 2,6-pyridine Schiff base and bromo dodecane were accurately weighed in turn, and anhydrous ethanol was added as solvent into the reactor, wherein the molar ratio of 2,6-pyridine Schiff base and bromo dodecane was 1:1.05, and the mass ratio of 2,6-pyridine Schiff base and anhydrous ethanol was 1:3, and the temperature was raised to 70℃, and refluxed for 5h to obtain the pyridine Schiff base quaternary ammonium salt corrosion inhibitor.

[0035] Example 6:

[0036] (1) 2,6-pyridine dicarboxaldehyde, aniline and excess solvent anhydrous ethanol were added into the reactor at 25℃, the molar ratio of 2,6-pyridine dicarboxaldehyde and aniline was 1:2.05, and the temperature was raised to 40-50℃ for stirring, after the raw materials were completely dissolved, glacial acetic acid was slowly added dropwise, the pH of the system was adjusted to 4.5, and then the reaction was carried out at 80℃ for 4h, and then the temperature was cooled to room temperature, and after filtration and recrystallization, 2,6-pyridine Schiff base was obtained.

[0037] (2) into the reactor with thermometer, stirrer, condenser and water separator, 2,6-pyridine Schiff base and sodium chloroacetate were accurately weighed in turn, and anhydrous ethanol was added as solvent into the reactor, wherein the molar ratio of 2,6-pyridine Schiff base and sodium chloroacetate was 1:1.05, and the mass ratio of 2,6-pyridine Schiff base and anhydrous ethanol was 1:3, and the temperature was raised to 60℃, and refluxed for 6h to obtain the pyridine Schiff base quaternary ammonium salt corrosion inhibitor.

[0038] Example 7:

[0039] (1) 2,6-pyridine dicarboxaldehyde, aniline and excess solvent anhydrous ethanol were added into the reactor at 25℃, the molar ratio of 2,6-pyridine dicarboxaldehyde and aniline was 1:2.00, and the temperature was raised to 50℃ for stirring, after the raw materials were completely dissolved, glacial acetic acid was slowly added dropwise, the pH of the system was adjusted to 5.0, and then the reaction was carried out at 80℃ for 6h, and then the temperature was cooled to room temperature, and after filtration and recrystallization, 2,6-pyridine Schiff base was obtained.

[0040] (2) into the reactor with thermometer, stirrer, condenser and water separator, 2,6-pyridine Schiff base and sodium chloroacetate were accurately weighed in turn, and anhydrous ethanol was added as solvent into the reactor, wherein the molar ratio of 2,6-pyridine Schiff base and sodium chloroacetate was 1:1.05, and the mass ratio of 2,6-pyridine Schiff base and anhydrous ethanol was 1:3, and the temperature was raised to 60℃, and refluxed for 6h to obtain the pyridine Schiff base quaternary ammonium salt corrosion inhibitor.

[0041] Effect experiment

[0042] Experimental conditions adopted:

[0043] Corrosion medium: take citric acid 0.05g (accurately weighed to 0.001g) into a beaker, add 500mL distilled water, add 1.0g (accurately weighed to 0.01g) corrosion inhibitor of examples 1-6, stir uniformly and use.

[0044] The experimental liquid is loaded into a pressure-resistant container, the weighed N80 test piece is immersed in the experimental liquid, sealed with a cover, placed in a heating box, and kept at a constant temperature of 160±1℃ for 72h.

[0045] Comparative corrosion inhibitor: Mannich base corrosion inhibitor.

[0046] The performance influence of the corrosion inhibitor of the examples and the comparative examples is shown in Table 1.

[0047] Table 1, performance influence of the corrosion inhibitor of the examples and the comparative examples

[0048] Test No. Corrosion Inhibitor Corrosion Rate (mm / a) 1 Comparative Corrosion Inhibitor 0.1420 2 Example 1 0.0821 3 Example 2 0.0991 4 Example 3 0.0736 5 Example 4 0.0102 6 Example 5 0.0846 7 Example 6 0.0968

[0049] As can be seen from Table 1, the corrosion inhibitor product developed by the application has excellent corrosion inhibition performance, which meets the corrosion prevention requirements of high-temperature oilfield acidizing operation.

Claims

1. A high temperature resistant water soluble Schiff base corrosion inhibitor characterized in that, The structural formula is shown as follows: wherein: R1 is simultaneously -Ph, -C 11 H 23 , -C8H 17 , -C 15 H 31 , 2-pyridyl; R2 is methyl, ethyl, -C 11 H 23 , -C8H 17 , -C 15 H 31 , -CH2CH2COONa; X is one of Cl, Br, I.

2. A method for preparing the high-temperature resistant water-soluble Schiff base corrosion inhibitor according to claim 1, characterized in that, It comprises the following steps: (1) 2,6-pyridine dimethyl formaldehyde and organic amine are added in a molar ratio of 1:2.00-2.05 in alcohol as a solvent, an acid is added to adjust the pH to 4-6, and then the mixture is reacted at 60-90 DEG C for 4-6 h, cooled, filtered, and recrystallized to obtain 2,6-pyridyl Schiff base, and the reaction formula is shown as follows: (2) the obtained 2,6-pyridyl Schiff base is placed in a reactor in alcohol as a solvent in a substance amount ratio of 1:(1.05-1.15) with halogenated hydrocarbon, heated, and subjected to quaternary amination reaction at 60-90 DEG C for 2-4 h, and then the alcohol solvent is evaporated to obtain a water-soluble Schiff base pyridine quaternary amine salt corrosion inhibitor, and the reaction formula is shown as follows:

3. The preparation method according to claim 2, characterized in that, The reaction temperature of the step 1) is 80-90 DEG C.

4. The production method according to claim 2, characterized by, The reaction temperature of the step 2) is 60-80 DEG C.

5. The preparation method according to claim 2, characterized in that, The alcohol solvent is anhydrous ethanol.

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