A trithiothiotriazine trisodium salt corrosion inhibitor and its preparation method and application

Abstract

The invention discloses a trithiothiotriazine trisodium salt corrosion inhibitor and its preparation method and application, and belongs to the technical field of corrosion inhibitor synthesis. The invention uses thiocyanuric acid as a raw material, and successfully grafts a carbon-carbon double bond to it by reacting with bromopropylene to generate an intermediate 2,4-dimercapto-6-mercaptopropenyl-1,3,5-triazine monomer, and then polymerizes it with allylthiourea, adds an initiator under nitrogen protection, and heats, stirs, purifies, and dries in a water bath to obtain a corrosion inhibitor; the corrosion inhibitor has excellent corrosion inhibition and bactericidal properties at the same time, can effectively solve the corrosion and microbial contamination problems in oil and gas field pipelines, still has excellent stability under high temperature environment, and meets the use requirements under extreme working conditions such as oil and gas fields.

Description

Technical Field

[0001] The invention belongs to the technical field of corrosion inhibitor and fungicide synthesis, and specifically relates to a trisodium salt of trimercaptotriazine corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] At present, shale gas development at home and abroad has made significant progress, but the resulting corrosion problem of gathering and transportation pipelines has become increasingly prominent. During the development of shale gas fields, the produced fluid is often accompanied by corrosive substances such as residual acid, CO2 and H2S, which are highly corrosive to downhole pipes and ground gathering and transportation systems. At the same time, the injection of water, drilling fluid, fracturing fluid, etc. will also bring harmful bacteria and microorganisms that are easy to cause metal corrosion into the production system, such as sulfate-reducing bacteria, saprophytes and iron bacteria. Taking shale gas fields such as Fuling, Changning and Weiyuan as examples, these areas generally face the problem of gathering and transportation pipeline corrosion during shale gas extraction. According to statistics, the gas field has an average of dozens of perforations due to pipeline corrosion per month, and many gas wells have been flooded and shut down due to pipeline corrosion perforation, which has seriously affected the process of efficient development of the gas field and caused huge economic losses. Although the corrosion inhibitors currently used can slow down corrosion to a certain extent, they generally do not have a bactericidal effect and need to be added separately. Although existing fungicides can effectively kill bacteria, they are often not compatible with corrosion inhibitors, which affects the overall effect. Therefore, for shale gas field oil and gas gathering and transportation pipelines, it is usually necessary to add corrosion inhibitors and fungicides separately, which not only increases the complexity of operation, but also may affect the effect due to incompatibility between components. Therefore, the development of a new type of corrosion inhibitor and fungicide with both excellent corrosion inhibition and high-efficiency bactericidal performance is of great significance to improving the development efficiency and safety of shale gas fields. Summary of the invention

[0003] In view of the above-mentioned prior art, the present invention provides a trisodium trithiotriazine corrosion inhibitor and fungicide, and a preparation method and application thereof, which solves the problem that shale gas field oil and gas gathering and transportation pipelines usually need to add corrosion inhibitors and fungicides separately, and the effects are affected by the incompatibility between the components.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: to provide a method for preparing a trisodium salt of trithiotriazine corrosion inhibitor and fungicide, comprising the following steps:

[0005] S1: Add thiocyanate to a mixed solution of sodium hydroxide and potassium carbonate, and stir at 40-80°C until dissolved to obtain solution 1;

[0006] S2: dissolving propylene bromide in an organic solvent to obtain solution 2, adding solution 2 to solution 1 to react for 3-8 hours, then adjusting the pH to acidic to precipitate, and drying the precipitate to obtain an intermediate product;

[0007] S3: The intermediate product is mixed with allylthiourea to obtain solution three, and then an initiator is added to solution three under nitrogen protection, and the mixture is reacted in a water bath at 50-90°C for 2-10 hours to obtain solution four;

[0008] S4: Add methyl tert-butyl ether solution to solution 4, centrifuge, filter and dry the precipitate to obtain a trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide.

[0009] The beneficial effects of the present invention are as follows: the present invention uses 2,4-dimercapto-6-mercaptopropenyl-1,3,5-triazine and allylthiourea as monomers, uses azobisisobutyronitrile as an initiator, and adopts an aqueous solution free radical polymerization method to perform copolymerization to form a polymer chain. In this process, a variety of functional groups are effectively introduced into the polymer chain to form a trisodium salt of trimercaptotriazine corrosion inhibitor with a cross-linked network structure. The corrosion inhibitor has important application value in the field of oil and gas gathering and transportation in shale gas fields due to its advantages of high corrosion inhibition performance, broad-spectrum bactericidal performance, environmentally friendly characteristics, good compatibility, easy use, simple process, etc.

[0010] Based on the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, the liquid ratio of thiocyanuric acid to the mixed solution of sodium hydroxide and potassium carbonate is 1-2 g:40-50 mL, the concentration of sodium hydroxide in the mixed solution of sodium hydroxide and potassium carbonate is 0.08 g-0.15 g / mL, and the concentration of potassium carbonate is 0.12 g-0.2 g / mL.

[0012] Furthermore, the volume ratio of propylene bromide to the organic solvent is 0.02-0.04:1, and the organic solvent is N,N-dimethylformamide.

[0013] Furthermore, the molar ratio of the intermediate product to the allylthiourea is 0.5-3:1.

[0014] Further, the dosage of the initiator is 1-3% of the volume of the solution, and the preparation steps of the initiator are:

[0015] Dissolve azobisisobutyronitrile in N,N-dimethylformamide, and the mass concentration of azobisisobutyronitrile is 0.3~0.6%.

[0016] Further, the amount of methyl tert-butyl ether solution added is 40-60% of solution 4.

[0017] Furthermore, the drying treatment in S2 is drying in a vacuum drying oven at 45-55° C. to constant weight, and the drying treatment in S4 is drying in a vacuum drying oven at 45-55° C. for 12-24 hours.

[0018] The beneficial effect of adopting the further technical solution is: adopting a suitable raw material ratio makes the final corrosion inhibitor and fungicide have excellent use effect.

[0019] The invention also discloses a preparation method of the trimercaptotriazine trisodium salt corrosion inhibitor and fungicide to obtain the trimercaptotriazine trisodium salt corrosion inhibitor and fungicide.

[0020] Furthermore, the molecular weight of the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide is 6000-7500.

[0021] The beneficial effects of the present invention are as follows: the trithiol triazine trisodium salt corrosion inhibitor bactericide of the present invention introduces a stable triazine ring and a thiourea structure capable of destroying the cell wall of microorganisms, and can quickly exert corrosion inhibition and bactericidal effects in a short time. When the corrosion inhibitor bactericide contacts bacteria, the thiourea group can penetrate the cell wall, destroy its integrity, cause the cell contents to leak out, and thus kill the microorganisms; and because the polymer chain of the corrosion inhibitor bactericide contains multiple thiol groups (-SH) and nitrogen heterocycles (triazine rings), it has high surface activity and can form a strong adsorption effect with the metal surface through coordination bonds and π electrons. This adsorption effect enables the corrosion inhibitor molecules to form a dense protective film on the metal surface, thereby effectively isolating the metal from the contact with the corrosive medium and slowing down or preventing the occurrence of corrosion reactions.

[0022] The invention also discloses the application of the trisodium salt of trimercaptotriazine corrosion inhibitor and bactericide in the maintenance of oil and gas gathering and transportation pipelines in shale gas fields.

[0023] The beneficial effects of the present invention are as follows: the trisodium salt of trimercaptotriazine corrosion inhibitor and bactericide of the present invention can be used for the sterilization and corrosion control of downhole pipes in shale gas fields, ground gathering and transportation pipelines, and produced water pipelines, and can also be used for corrosion control and sterilization of pipelines in other types of oil fields and gas fields; and because of its low dosage and excellent corrosion inhibition and bactericidal performance, it has lower toxicity and better biodegradability, and meets the requirements of modern industry for green chemicals. DETAILED DESCRIPTION

[0024] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0025] Example 1

[0026] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0027] S1: Take 1.20g of thiocyanuric acid and add it to 40mL of a mixed solution of sodium hydroxide and potassium carbonate (4g of sodium hydroxide and 6g of potassium carbonate are dissolved in 40mL of water), stir at 60°C until dissolved, and obtain solution 1;

[0028] S2: Take 0.70 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 5 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum oven at 50 ° C to constant weight to obtain an intermediate product.

[0029] S3: The intermediate product and allylthiourea were mixed at a molar ratio of 0.5:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.5% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 1% of the volume of solution three), and the reaction was carried out in a water bath at 70°C for 8 hours to obtain solution four;

[0030] S4: Add 50% of the volume of solution 4 of methyl tert-butyl ether to solution 4 to precipitate a solid polymer, centrifuge and filter the precipitate, and dry it in a vacuum drying oven at 50° C. for 12 hours; obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 6500.

[0031] Example 2

[0032] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0033] S1: Take 1g of thiocyanuric acid and add it to 50mL of a mixed solution of sodium hydroxide and potassium carbonate (4g of sodium hydroxide and 6g of potassium carbonate are dissolved in 50mL of water), stir at 50°C until dissolved, and obtain solution 1;

[0034] S2: Take 0.40 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 3 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum drying oven at 45 ° C to constant weight to obtain an intermediate product.

[0035] S3: The intermediate product and allylthiourea were mixed at a molar ratio of 0.8:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.5% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 2% of the volume of solution three), and the reaction was carried out in a water bath at 80°C for 4 hours to obtain solution four;

[0036] S4: Add 40% of the volume of solution 4 of methyl tert-butyl ether to solution 4 to precipitate a solid polymer, centrifuge and filter the precipitate, and place it in a vacuum drying oven at 45°C for 18 hours to obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 6000.

[0037] Example 3

[0038] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0039] S1: Take 2g of thiocyanuric acid and add it to 40mL of a mixed solution of sodium hydroxide and potassium carbonate (6g of sodium hydroxide and 8g of potassium carbonate are dissolved in 40mL of water), stir at 90°C until dissolved, and obtain solution 1;

[0040] S2: Take 0.80 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 8 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum oven at 40 ° C to constant weight to obtain an intermediate product.

[0041] S3: The intermediate product and allylthiourea were mixed in a molar ratio of 1:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.5% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 1.5% of the volume of solution three), and the reaction was carried out in a water bath at 70°C for 2h to obtain solution four;

[0042] S4: Add methyl tert-butyl ether (60% by volume of solution 4) to solution 4 to precipitate a solid polymer. Centrifuge and filter the precipitate, and dry it in a vacuum drying oven at 40°C for 24 hours to obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 7000.

[0043] Example 4

[0044] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0045] S1: Take 1.20g of thiocyanuric acid and add it to 40mL of a mixed solution of sodium hydroxide and potassium carbonate (4g of sodium hydroxide and 6g of potassium carbonate are dissolved in 40mL of water), stir at 60°C until dissolved, and obtain solution 1;

[0046] S2: Take 0.70 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 5 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum oven at 50 ° C to constant weight to obtain an intermediate product.

[0047] S3: The intermediate product and allylthiourea were mixed at a molar ratio of 1.75:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.3% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 2% of the volume of solution three), and the reaction was carried out in a water bath at 70°C for 5 hours to obtain solution four;

[0048] S4: Add 50% of the volume of solution 4 of methyl tert-butyl ether to solution 4 to precipitate a solid polymer, centrifuge and filter the precipitate, and dry it in a vacuum drying oven at 50°C for 12 hours; and obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 6700.

[0049] Example 5

[0050] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0051] S1: Take 1.20g of thiocyanuric acid and add it to 40mL of a mixed solution of sodium hydroxide and potassium carbonate (4g of sodium hydroxide and 6g of potassium carbonate are dissolved in 40mL of water), stir at 60°C until dissolved, and obtain solution 1;

[0052] S2: Take 0.70 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 5 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum oven at 50 ° C to constant weight to obtain an intermediate product.

[0053] S3: The intermediate product and allylthiourea were mixed in a molar ratio of 3:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.6% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 1% of the volume of solution three), and the reaction was carried out in a water bath at 90°C for 2h to obtain solution four;

[0054] S4: Add 50% of the volume of solution 4 of methyl tert-butyl ether to solution 4 to precipitate a solid polymer, centrifuge and filter the precipitate, and dry it in a vacuum drying oven at 50°C for 12 hours; and obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 7500.

[0055] Example 6

[0056] A method for preparing a trisodium trithiotriazine corrosion inhibitor and fungicide comprises the following steps:

[0057] S1: Take 1.20g of thiocyanuric acid and add it to 40mL of a mixed solution of sodium hydroxide and potassium carbonate (4g of sodium hydroxide and 6g of potassium carbonate are dissolved in 40mL of water), stir at 60°C until dissolved, and obtain solution 1;

[0058] S2: Take 0.70 mL of propylene bromide and dissolve it in 20 mL of N, N-dimethylformamide to obtain solution 2. Add solution 2 to solution 1 and react for 5 h. Then add 18% hydrochloric acid to adjust the pH to 2 to precipitate. Dry the precipitate in a vacuum oven at 50 ° C to constant weight to obtain an intermediate product.

[0059] S3: The intermediate product and allylthiourea were mixed in a molar ratio of 1:1 to obtain solution three; then azobisisobutyronitrile was weighed and dissolved in N,N-dimethylformamide to prepare a solution with a mass concentration of 0.5% as an initiator, and the initiator was added to solution three under nitrogen protection (the amount added was 2% of the volume of solution three), and the reaction was carried out in a water bath at 90°C for 8 hours to obtain solution four;

[0060] S4: Add 50% of the volume of solution 4 of methyl tert-butyl ether to solution 4 to precipitate a solid polymer, centrifuge and filter the precipitate, and dry it in a vacuum drying oven at 50°C for 12 hours; obtain a trisodium salt of trimercaptotriazine corrosion inhibitor with a molecular weight of 6600.

[0061] Experimental Example 1

[0062] Dynamic corrosion test: The corrosion inhibition rate of the trisodium salt of trimercaptotriazine corrosion inhibitor obtained in Examples 1-6 was evaluated by a GSH-2L high temperature and high pressure reactor dynamic corrosion test.

[0063] Experimental medium: Bacterial water from the on-site flowback fluid of a shale gas production platform in Sichuan

[0064] Experimental material: L245 steel

[0065] Experimental gas phase composition: 0.5MPa CO2+4MPa N2

[0066] Experimental conditions: temperature 60°C, speed 0.5m / s, reagent concentration 30mg / L

[0067] The test period is 7 days, and the experimental results are shown in Table 1:

[0068] Table 1 Corrosion inhibition rate statistics

[0069]

[0070] As shown in Table 1, the corrosion inhibition rate of the trisodium salt of trimercaptotriazine corrosion inhibitors in Examples 1-6 for L245 steel is above 90%, and the corrosion inhibition inhibitor in Example 2 can reduce the corrosion rate of L245 steel to 0.0452 mm / a, with a corrosion inhibition rate of up to 98.74%, far exceeding the industry standard (industry standard: corrosion inhibition rate ≤ 0.076 mm / a). Therefore, the corrosion inhibition inhibitor in the present invention has a high corrosion inhibition performance and can be used to control the corrosion of shale gas pipelines.

[0071] Experimental Example 2

[0072] Bactericidal experiment: The bactericidal effect of the trisodium salt of trithiotriazine corrosion inhibitor in Examples 1-6 was evaluated. The corresponding culture medium was prepared according to the "Extinct Dilution Method Standard for Bacterial Analysis of Oil and Gas Field Injection Water" SY / T0532-2012, and the sulfate-reducing bacteria in the blank water sample were measured by the extinct dilution method to be 4500 / mL, the saprophytic bacteria were 140000 / mL, and the iron bacteria were 11000 / mL.

[0073] Experimental conditions: temperature 60℃, time 72h, drug concentration 30mg / L.

[0074] The test results are shown in Table 2.

[0075] Table 2 Sterilization effect statistics

[0076]

[0077] It can be seen from Table 2 that the trisodium salt of trimercaptotriazine corrosion inhibitors in Examples 1-6 have a sterilization rate of up to 99.99% against sulfate-reducing bacteria, a sterilization rate of up to 99.77% against iron bacteria, and a sterilization rate of up to 99.98% against saprophytic bacteria. They have broad-spectrum sterilization properties and can effectively control microbial corrosion of shale gas pipelines and equipment.

[0078] In summary, the present invention provides a corrosion inhibitor and bactericide solution that is both environmentally friendly and simple in process. It combines 2,4-dimercapto-6-mercaptopropenyl-1,3,5-triazine monomer with allyl thiourea, and enhances the overall effect through a synergistic mechanism, so that it has both corrosion inhibition and bactericidal properties. It has high corrosion inhibition and bactericidal efficiency and stable performance, and can adapt to the complex and changeable environmental conditions of shale gas fields. It can significantly extend the service life of shale gas pipelines and reduce losses caused by corrosion and microbial contamination. It is an economical and efficient multifunctional corrosion inhibitor and bactericide.

[0079] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. A method for preparing a trisodium salt of trithiotriazine corrosion inhibitor bactericide, characterized in that: The following steps are involved: S1: Add thiocyanate to a mixed solution of sodium hydroxide and potassium carbonate, and stir at 40-80°C until dissolved to obtain solution 1; S2: dissolving propylene bromide in an organic solvent to obtain solution 2, adding solution 2 to solution 1 to react for 3-8 hours, then adjusting the pH to acidic to precipitate, and drying the precipitate to obtain an intermediate product; S3: The intermediate product is mixed with allylthiourea to obtain solution three, and then an initiator is added to solution three under nitrogen protection, and the mixture is reacted in a water bath at 50-90°C for 2-10 hours to obtain solution four; S4: Add methyl tert-butyl ether solution to solution 4, centrifuge, filter and dry the precipitate to obtain a trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide.

2. The method for preparing the trisodium salt of trithiotriazine corrosion inhibitor according to claim 1, characterized in that: The solid-liquid ratio of the thiocyanuric acid to the mixed solution of sodium hydroxide and potassium carbonate is 1-2 g:40-50 mL, the concentration of sodium hydroxide in the mixed solution of sodium hydroxide and potassium carbonate is 0.08 g-0.15 g / mL, and the concentration of potassium carbonate is 0.12 g-0.2 g / mL.

3. The method for preparing the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide according to claim 1, characterized in that: The volume ratio of the propylene bromide to the organic solvent is 0.02-0.04:1, and the organic solvent is N,N-dimethylformamide.

4. The method for preparing the trisodium salt of trithiotriazine corrosion inhibitor according to claim 1, characterized in that: The molar ratio of the intermediate product to allylthiourea is 0.5-3:

1.

5. The method for preparing the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide according to claim 1, characterized in that: The dosage of the initiator is 1-3% of the volume of the solution. The preparation steps of the initiator are: Dissolve azobisisobutyronitrile in N,N-dimethylformamide, and the mass concentration of azobisisobutyronitrile is 0.3~0.6%.

6. The method for preparing the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide according to claim 1, characterized in that: The amount of methyl tert-butyl ether added is 40-60% of solution 4.

7. The method for preparing the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide according to claim 1, characterized in that: The drying process in S2 is drying in a vacuum drying oven at 45-55° C. to constant weight, and the drying process in S4 is drying in a vacuum drying oven at 45-55° C. for 12-24 hours.

8. The trisodium salt corrosion inhibitor of trimercaptotriazine obtained by the preparation method according to any one of claims 1 to 7.

9. The trisodium salt corrosion inhibitor of trimercaptotriazine according to claim 8, characterized in that: The molecular weight of the trithiothiotriazine trisodium salt corrosion inhibitor and bactericide is 6000-7500.

10. Use of the trisodium salt of trimercaptotriazine corrosion inhibitor and fungicide according to claim 8 in the maintenance of oil and gas gathering and transportation pipelines in shale gas fields.

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