A high temperature corrosion inhibitor and preparation method thereof

Abstract

The invention relates to the technical field of corrosion inhibitors, and discloses a high temperature corrosion inhibitor and a preparation method thereof. The invention obtains the high temperature corrosion inhibitor by adding boric acid modified chitosan, a triazine-based corrosion inhibitor and deionized water into a reactor and stirring. The lone pair electrons provided by a large number of free hydroxyl groups in the chitosan in the boric acid modified chitosan can be well adsorbed to the metal, thereby protecting the metal from corrosion by the corrosive medium; the boron element inhibits the corrosion process by forming a protective oxide film or adsorption film on the metal surface; the ferrocene group itself also has a good corrosion inhibition effect. The quaternary ammonium salt group and the sulfonic acid group in the triazine-based corrosion inhibitor can prevent further corrosion of the metal.

Description

Technical Field

[0001] The invention relates to the technical field of corrosion inhibitors, in particular to a high temperature resistant corrosion inhibitor and a preparation method thereof. Background Art

[0002] The transportation and production of oil and gas in oil and gas fields or natural gas in natural gas pipelines may often cause corrosion of equipment, pipelines, etc. In severe cases, the pipes may break directly, thus affecting their normal transportation. If transported in a high-temperature environment, the high-temperature resistance of the corrosion inhibitor is poor and it is difficult to play a corrosion-inhibiting role. Therefore, how to avoid this phenomenon is the key to solving the problem.

[0003] For example, patent CN102409344B discloses a composite corrosion inhibitor and its preparation method. The composite corrosion inhibitor has a good synergistic corrosion inhibition effect at pH = 6.1-9.1 and a temperature range of 40-90°C, effectively reducing the annual corrosion rate of equipment and pipelines. The corrosion inhibition efficiency reaches 95.3%, but its high temperature resistance effect needs to be improved. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a high temperature resistant corrosion inhibitor and a preparation method thereof, which have good corrosion inhibition effect.

[0006] (II) Technical solution

[0007] To achieve the above object, the present invention provides the following technical solution: a high temperature resistant corrosion inhibitor, comprising the following weight components: 5-8 weight parts of boric acid modified chitosan, 3-7 weight parts of triazine-based corrosion inhibitor, and 20-30 weight parts of deionized water;

[0008] The preparation method of the boric acid modified chitosan is:

[0009] Step 1: swell 1.61-1.63g of chitosan in 3% acetic acid solution for 1-2h, then add 15-18ml of benzaldehyde solution, react at 70-85°C for 4-6h, adjust pH to 10 with sodium hydroxide after reaction, filter, wash with anhydrous ethanol, and dry to obtain chitosan benzaldehyde Schiff base; wherein the benzaldehyde solution is prepared by dissolving 6.37g of benzaldehyde in 20ml of anhydrous ethanol to obtain a benzaldehyde solution;

[0010] Step 2: Add 3.4-3.9 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 2.1-3.2 g of chitosan benzaldehyde Schiff base thereto, react at 115-125° C., after the reaction is completed, perform vacuum distillation, filter and dry to obtain boric acid modified chitosan.

[0011] Preferably, the mass fraction of sodium hydroxide in step 1 is 9-10%.

[0012] Preferably, the reaction time in step 2 is 8-12 hours.

[0013] Preferably, the preparation method of the triazine-based corrosion inhibitor is:

[0014] S1. Add 18.46-18.79 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 10.1-12.4 g of anhydrous sodium carbonate, and 26-40 ml of 1,6-hexanediamine solution to the reactor, and stir the reaction in a water bath at 35-45 ° C. After the reaction, cool and add dilute hydrochloric acid dropwise to adjust the pH to 4-5 to obtain intermediate 1; wherein the 1,6-hexanediamine solution is prepared by dissolving 5.81 g of 1,6-hexanediamine in 50 ml of water to obtain a 1,6-hexanediamine solution;

[0015] S2. Add 6.84-7.65 g of intermediate 1 and 15.41-17.69 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add p-toluenesulfonic acid catalyst, stir and react at 90-110° C. for 6-10 h, and then perform vacuum distillation and washing to obtain a tertiary amine-modified amino acid triazine compound;

[0016] S3. Add 5.14-6.47 g of tertiary amine-modified amino acid triazine compound and 14.17-16.59 g of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add 2-5% by mass sodium hydroxide solution, react for 5-8 hours, and after the reaction, concentrate under reduced pressure to remove the solvent. The crude product is recrystallized in ethanol to obtain a triazine-based corrosion inhibitor.

[0017] Preferably, the stirring time in S1 is 1-2h.

[0018] Preferably, the mass of the p-toluenesulfonic acid catalyst in S2 is 0.012-0.023 g.

[0019] Preferably, the reaction temperature in S3 is 75-90°C.

[0020] Preferably, the preparation method of the high temperature resistant corrosion inhibitor is: adding boric acid modified chitosan, triazine-based corrosion inhibitor and deionized water into a reactor, stirring at 35-45° C. for 10-15 minutes to obtain the high temperature resistant corrosion inhibitor.

[0021] 3. Beneficial technical effects

[0022] The invention obtains the high temperature resistant corrosion inhibitor by adding boric acid modified chitosan, triazine-based corrosion inhibitor and deionized water into a reactor and stirring the mixture.

[0023] The lone pair electrons provided by the large number of free hydroxyl groups in the chitosan modified with boric acid can be well adsorbed with the metal, thereby protecting the metal from corrosion by the corrosive medium; the boron element inhibits the corrosion process by forming a protective oxide film or adsorption film on the metal surface; the ferrocene group itself also has a good corrosion inhibition effect. The quaternary ammonium salt group in the triazine-based corrosion inhibitor can form a protective film on the metal surface, change the metal surface state and double electric layer structure, increase the activation energy of the corrosion reaction, and thus reduce the corrosion rate of the metal; the sulfonic acid group can form a dense protective film on the metal surface, which prevents further corrosion of the metal by isolating the corrosive medium. The present invention reacts the carboxyl group in the intermediate with the hydroxyl group in 1,3-di(dimethylamino)-2-propanol, introduces a tertiary amine, and further reacts with 1,3-propane sultone to generate a large number of quaternary ammonium salt groups and sodium sulfonate groups, thereby increasing the degree of substitution of the two groups and further improving its corrosion inhibition effect. The boron element in boric acid-modified chitosan and the triazine group in triazine-based corrosion inhibitor both have good high temperature resistance. DETAILED DESCRIPTION

[0024] The preparation method of 1-chloro-3,5-aminoacetic acid-isotriazine intermediate refers to the journal "Fine Chemicals", the document "Synthesis and Corrosion Inhibition Performance of N,N'-di(4,6-diaminoacid-1,3,5-triazine)-hexanediamine", DOI number: 10.13550 / j.jxhg.20220529.

[0025] In an ice-salt bath, 0.4 mol of Na2CO3 and 0.21 mol of aminoacetic acid were added to 300 mL of distilled water, and then 200 mL of a 1,4-dioxane solution containing 0.1 mol of cyanuric chloride was added dropwise for 2 h. The reaction was stirred at room temperature for 2 h to obtain a 1-chloro-3,5-aminoacetic acid-based triazine intermediate. Example 1

[0026] (1) 1.61 g of chitosan was swollen in a 3% acetic acid solution for 1 h, and then 15 ml of benzaldehyde solution was added thereto, and the mixture was reacted at 70°C for 4 h. After the reaction, the pH value was adjusted to 10 using 9% sodium hydroxide, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain chitosan benzaldehyde Schiff base;

[0027] (2) Add 3.4 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 2.1 g of chitosan benzaldehyde Schiff base thereto, react at 115 °C for 8 h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain boric acid modified chitosan;

[0028] (3) Add 18.46 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 10.1 g of anhydrous sodium carbonate, and 26 ml of 1,6-hexanediamine solution into the reactor, stir and react at 35° C. in a water bath for 1 h. After the reaction, cool and add dilute hydrochloric acid dropwise to adjust the pH to 4 to obtain intermediate 1;

[0029] (4) Add 6.84 g of intermediate 1 and 15.41 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add 0.012 g of p-toluenesulfonic acid catalyst, stir and react at 90°C for 6 h, and then distill under reduced pressure and wash to obtain a tertiary amine-modified amino acid triazine compound;

[0030] (5) Add 5.14 g of tertiary amine-modified amino acid triazine compound and 14.17 g of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add 2% by mass sodium hydroxide solution, react at 75° C. for 5 h, and after the reaction, concentrate under reduced pressure to remove the solvent. The crude product is recrystallized in ethanol to obtain a triazine-based corrosion inhibitor;

[0031] (6) Add 5 parts by weight of boric acid-modified chitosan, 3 parts by weight of triazine-based corrosion inhibitor, and 20 parts by weight of deionized water into a reactor, and stir at 35° C. for 10 minutes to obtain a high temperature resistant corrosion inhibitor. Example 2

[0032] (1) 1.63 g of chitosan was swelled in a 3% acetic acid solution for 2 h, and then 18 ml of benzaldehyde solution was added thereto, and the mixture was reacted at 85°C for 6 h. After the reaction, the pH value was adjusted to 10 using 10% sodium hydroxide, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain chitosan benzaldehyde Schiff base;

[0033] (2) Add 3.9 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 3.2 g of chitosan benzaldehyde Schiff base, react at 125 °C for 12 h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain boric acid modified chitosan;

[0034] (3) Add 18.79 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 12.4 g of anhydrous sodium carbonate, and 40 ml of 1,6-hexanediamine solution into the reactor, stir and react for 2 h in a water bath at 45 °C, cool after the reaction, and add dilute hydrochloric acid dropwise to adjust the pH to 5 to obtain intermediate 1;

[0035] (4) Add 7.65 g of intermediate 1 and 17.69 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add 0.023 g of p-toluenesulfonic acid catalyst, stir and react at 110° C. for 10 h, and then distill under reduced pressure and wash to obtain a tertiary amine-modified amino acid triazine compound;

[0036] (5) Add 6.47 g of tertiary amine-modified amino acid triazine compound and 16.59 g of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add 5% by mass sodium hydroxide solution, react at 90° C. for 8 h, and after the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain a triazine-based corrosion inhibitor;

[0037] (6) Add 8 parts by weight of boric acid-modified chitosan, 7 parts by weight of triazine-based corrosion inhibitor, and 30 parts by weight of deionized water into a reactor, and stir at 45° C. for 15 minutes to obtain a high temperature resistant corrosion inhibitor. Example 3

[0038] (1) 1.62 g of chitosan was swollen in a 3% acetic acid solution for 1 h, and then 16 ml of benzaldehyde solution was added thereto, and the mixture was reacted at 75°C for 5 h. After the reaction, the pH was adjusted to 10 using 9% sodium hydroxide, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain chitosan benzaldehyde Schiff base;

[0039] (2) Add 3.6 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 2.8 g of chitosan benzaldehyde Schiff base thereto, react at 120°C for 10 h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain boric acid modified chitosan;

[0040] (3) Add 18.67 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 11.6 g of anhydrous sodium carbonate, and 30 ml of 1,6-hexanediamine solution into the reactor, stir and react for 2 h in a water bath at 40 °C, cool after the reaction, and add dilute hydrochloric acid dropwise to adjust the pH to 5 to obtain intermediate 1;

[0041] (4) Add 7.62 g of intermediate 1 and 16.47 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add 0.012 g of p-toluenesulfonic acid catalyst, stir and react at 105°C for 8 h, and then distill under reduced pressure and wash to obtain a tertiary amine-modified amino acid triazine compound;

[0042] (5) Add 6.25 g of a tertiary amine-modified amino acid triazine compound and 15.69 g of 1,3-propane sultone to an acetone solvent for dissolution, then dropwise add a 2-5% by mass sodium hydroxide solution, react at 85° C. for 7 h, and after the reaction, concentrate under reduced pressure to remove the solvent. The crude product is recrystallized in ethanol to obtain a triazine-based corrosion inhibitor;

[0043] (6) Add 7 parts by weight of boric acid-modified chitosan, 5 parts by weight of triazine-based corrosion inhibitor, and 15 parts by weight of deionized water into a reactor, and stir at 40° C. for 12 minutes to obtain a high temperature resistant corrosion inhibitor. Example 4

[0044] (1) 1.61 g of chitosan was swollen in a 3% acetic acid solution for 1 h, and then 15 ml of benzaldehyde solution was added thereto, and the mixture was reacted at 70°C for 4 h. After the reaction, the pH value was adjusted to 10 using 9% sodium hydroxide, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain chitosan benzaldehyde Schiff base;

[0045] (2) Add 3.4 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 2.1 g of chitosan benzaldehyde Schiff base thereto, react at 115 °C for 8 h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain boric acid modified chitosan;

[0046] (3) Add 18.79 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 12.4 g of anhydrous sodium carbonate, and 32 ml of 1,6-hexanediamine solution to the reactor, stir and react for 2 h in a water bath at 45 °C, cool after the reaction, and add dilute hydrochloric acid dropwise to adjust the pH to 5 to obtain intermediate 1;

[0047] (4) Add 7.65 g of intermediate 1 and 17.69 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add 0.023 g of p-toluenesulfonic acid catalyst, stir and react at 110° C. for 10 h, and then distill under reduced pressure and wash to obtain a tertiary amine-modified amino acid triazine compound;

[0048] (5) Add 6.47 g of tertiary amine-modified amino acid triazine compound and 16.59 g of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add 5% by mass sodium hydroxide solution, react at 90° C. for 8 h, and after the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain a triazine-based corrosion inhibitor;

[0049] (6) Add 8 parts by weight of boric acid-modified chitosan, 7 parts by weight of triazine-based corrosion inhibitor, and 30 parts by weight of deionized water into a reactor, and stir at 45° C. for 15 minutes to obtain a high temperature resistant corrosion inhibitor. Example 5

[0050] (1) 1.63 g of chitosan was swelled in a 3% acetic acid solution for 2 h, and then 16 ml of benzaldehyde solution was added thereto, and the mixture was reacted at 85°C for 6 h. After the reaction, the pH value was adjusted to 10 using 10% sodium hydroxide, and the mixture was filtered, washed with anhydrous ethanol, and dried to obtain chitosan benzaldehyde Schiff base;

[0051] (2) Add 3.9 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 3.2 g of chitosan benzaldehyde Schiff base, react at 125 °C for 12 h, and after the reaction is completed, distill under reduced pressure, filter and dry to obtain boric acid modified chitosan;

[0052] (3) Add 18.67 g of 1-chloro-3,5-aminoacetic acid-s-triazine intermediate, 11.6 g of anhydrous sodium carbonate, and 30 ml of 1,6-hexanediamine solution into the reactor, stir and react for 2 h in a water bath at 40 °C, cool after the reaction, and add dilute hydrochloric acid dropwise to adjust the pH to 5 to obtain intermediate 1;

[0053] (4) Add 7.62 g of intermediate 1 and 16.47 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add 0.012 g of p-toluenesulfonic acid catalyst, stir and react at 105°C for 8 h, and then distill under reduced pressure and wash to obtain a tertiary amine-modified amino acid triazine compound;

[0054] (5) Add 5.14 g of tertiary amine-modified amino acid triazine compound and 14.17 g of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add 2% by mass sodium hydroxide solution, react at 75° C. for 5 h, and after the reaction, concentrate under reduced pressure to remove the solvent. The crude product is recrystallized in ethanol to obtain a triazine-based corrosion inhibitor;

[0055] (6) Add 5 parts by weight of boric acid-modified chitosan, 3 parts by weight of triazine-based corrosion inhibitor, and 20 parts by weight of deionized water into a reactor, and stir at 35° C. for 10 minutes to obtain a high temperature resistant corrosion inhibitor.

[0056] Comparative Example 1

[0057] The difference between this comparative example and Example 5 is that chitosan is used instead of boric acid-modified chitosan.

[0058] Comparative Example 2

[0059] The difference between this comparative example and Example 5 is that cyanuric chloride is used instead of the triazine-based corrosion inhibitor.

[0060] Performance Testing

[0061] Determination of the corrosion inhibition performance of the corrosion inhibitor: Using 12% hydrochloric acid as the corrosive medium and P110 carbon steel, the corrosion inhibition performance of Examples 1-5 and Comparative Examples 1-2 was determined by a 4h corrosion coupon test at 90°C. The amount of corrosion inhibitor used was 1000ppm. The results are shown in Table 1.

[0062] Table 1: Corrosion inhibition performance test

[0063] project Surface morphology Corrosion inhibition rate (%) <![CDATA[Corrosion rate (gm -2 h -1 )]]> Example 1 Smooth and flat 96.13 25.08 Example 2 Smooth and flat 97.25 24.89 Example 3 Smooth and flat 96.21 25.03 Example 4 Smooth and flat 97.22 25.07 Example 5 Smooth and flat 97.19 25.06 Comparative Example 1 Slightly uneven 82.34 31.49 Comparative Example 2 Slightly uneven 81.27 33.38

[0064] It can be seen from Table 1 that the high temperature resistant corrosion inhibitor of the present invention, Examples 1-5 have better corrosion inhibition effects than Comparative Examples 1-2.

[0065] Determination of the corrosion inhibition performance of the corrosion inhibitor: Using 20% ​​hydrochloric acid as the corrosive medium and P110 carbon steel, the corrosion inhibition performance of Examples 1-5 and Comparative Examples 1-2 was determined by a 4h corrosion coupon test at 200°C. The amount of corrosion inhibitor used was 1000ppm. The results are shown in Table 2.

[0066] Table 2: Corrosion inhibition performance test

[0067] project Surface morphology Corrosion inhibition rate (%) <![CDATA[Corrosion rate (gm -2 h -1 )]]> Example 1 Smooth and flat 95.57 25.19 Example 2 Smooth and flat 95.83 24.93 Example 3 Smooth and flat 95.62 25.18 Example 4 Smooth and flat 95.59 24.95 Example 5 Smooth and flat 95.64 25.04 Comparative Example 1 Slightly uneven 79.15 33.85 Comparative Example 2 Slightly uneven 78.36 34.68

[0068] It can be seen from Table 2 that the high temperature resistant corrosion inhibitor of the present invention, Examples 1-5 have better corrosion inhibition effects than Comparative Examples 1-2.

[0069] It can be seen from Table 1 and Table 2 that the high temperature corrosion inhibitor of the present invention, Examples 1-5 have better corrosion inhibition rates at 90°C and 180°C than Comparative Examples 1-2, indicating better high temperature resistance.

[0070] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high temperature corrosion inhibitor, characterized in that: The invention comprises the following components by weight: 5-8 parts by weight of boric acid modified chitosan, 3-7 parts by weight of triazine-based corrosion inhibitor, and 20-30 parts by weight of deionized water; The preparation method of the boric acid modified chitosan is: Step 1: swell 1.61-1.63 g of chitosan in a 3% acetic acid solution for 1-2 h, then add 15-18 ml of benzaldehyde solution, react at 70-85° C. for 4-6 h, adjust the pH to 10 with sodium hydroxide after the reaction, filter, wash with anhydrous ethanol, and dry to obtain chitosan benzaldehyde Schiff base; Step 2: Add 3.4-3.9 g of ferrocenylboric acid to toluene solvent, stir and disperse, then add 2.1-3.2 g of chitosan benzaldehyde Schiff base thereto, react at 115-125° C., after the reaction is completed, perform vacuum distillation, filter and dry to obtain boric acid modified chitosan; The mass fraction of sodium hydroxide in the step 1 is 9-10%; The reaction time in step 2 is 8-12h; The preparation method of the triazine-based corrosion inhibitor is: S1. Add 18.46-18.79 g of 1-chloro-3,5-aminoacetoxy-s-triazine intermediate, 10.1-12.4 g of anhydrous sodium carbonate, and 26-40 ml of 1,6-hexanediamine solution to the reactor, and stir the reaction in a water bath at 35-45 ° C. After the reaction, cool and add dilute hydrochloric acid dropwise to adjust the pH to 4-5 to obtain intermediate 1; S2. Add 6.84-7.65 g of intermediate 1 and 15.41-17.69 g of 1,3-di(dimethylamino)-2-propanol to N,N-dimethylformamide solvent, stir and mix, continue to add p-toluenesulfonic acid catalyst, stir and react at 90-110° C. for 6-10 h, and then perform vacuum distillation and washing to obtain a tertiary amine-modified amino acid triazine compound; S3. Add 5.14-6.47 g of a tertiary amine-modified amino acid triazine compound and 14.17-16.59 g of 1,3-propane sultone to an acetone solvent for dissolution, then dropwise add a 2-5% mass fraction of a sodium hydroxide solution, react for 5-8 h, and after the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain a triazine-based corrosion inhibitor; The stirring time in S1 is 1-2h; The mass of the p-toluenesulfonic acid catalyst in S2 is 0.012-0.023 g; The reaction temperature in S3 is 75-90°C.

2. A method for preparing a high temperature corrosion inhibitor as claimed in claim 1, characterized in that: The preparation method of the high temperature corrosion inhibitor is as follows: adding boric acid modified chitosan, triazine-based corrosion inhibitor and deionized water into a reactor, stirring at 35-45° C. for 10-15 minutes, and obtaining the high temperature corrosion inhibitor.