Preparation method of degradable bactericide for oil field

Abstract

This invention relates to the field of organic polymer compound technology and discloses a method for preparing a biodegradable bactericide for oilfield use. The method involves a ring-opening reaction of succinic anhydride with 1,8-diamino-3,6-dioxaoctane, followed by esterification polymerization with N-Boc-serine alcohol to remove the Boc protecting group. Finally, the reaction proceeds with the epoxy group of glycidyl dimethyl dodecyl ammonium chloride to obtain the biodegradable bactericide for oilfield use. The bactericide's side chain contains a large number of quaternary ammonium salt antibacterial groups, exhibiting strong bactericidal properties. Furthermore, it possesses good hydrophilicity and water solubility, which improves the dispersibility and surface activity of the bactericide in oilfield water, enhances the adsorption of the bactericide to bacterial cells, and ensures sufficient contact between the bactericide and bacterial cells, thus better exerting the bactericidal performance. It also exhibits excellent heat resistance and biodegradability.

Description

Technical Field

[0001] This invention relates to the field of organic polymer compound technology, specifically to a method for preparing a biodegradable bactericide for oil fields. Background Technology

[0002] Oilfield water injection systems contain a large number of sulfate-reducing bacteria, iron bacteria, saprophytic bacteria, and heterotrophic bacteria. During their growth, metabolism, and reproduction, these bacteria can corrode drilling and production equipment, water injection pipelines, and other equipment, clogging pipes and injection wells, thus reducing oil production and oil and gas quality. Currently, bacterial control measures in oilfield water injection systems mainly include cleaning the injection system, microbial control methods, ultraviolet irradiation sterilization, and chemical sterilization. Among these, chemical sterilization is the most widely used due to its convenience, speed, and significant sterilization effect. Developing high-performance oilfield bactericides is a research hotspot.

[0003] Currently, the main bactericides used in oilfields include urea-based bactericides, isothiazolinone bactericides, and quaternary ammonium salt bactericides. Compared to small-molecule bactericides, macromolecular polymer bactericides have stronger structural stability and better heat resistance, making them suitable for the complex and harsh environment of high temperature and high salinity in oilfield water injection systems. However, macromolecular polymers have poor water solubility, which affects their bactericidal performance. Patent CN114957525A discloses a bactericide for oilfield wastewater treatment and its synthesis method. The classification number is C08. The synthesis method is as follows: 2-cyclohexen-1-one is added to a nitrogen-protected four-necked flask, followed by the slow addition of dibutylphosphine, then ethanol and 1,4-dichloro-2-butene. The mixture is stirred, heated under reflux, and distilled under reduced pressure. Ethyl acetate is then added to the crude product, heated to dissolve, filtered, and the filtrate is cooled to below 10°C to precipitate crystals. In another flask, the monomer and water are added, followed by the addition of an initiator. The mixture is heated to 60-70°C and reacted for 15-30 minutes. A 20wt% sodium bisulfite solution is added to obtain a pale yellow solid, which is then pulverized to 30-60 mesh particles to obtain the bactericide. This bactericide has the advantages of wide availability of raw materials, simple synthesis process, broad-spectrum bactericidal activity, low dosage, and high bactericidal efficiency. Another invention patent, CN114751498B (classification C08), discloses a flocculant for sterilizing and removing oil from oily wastewater in oilfields, its preparation method, and its application. The preparation method is as follows: Tributylphosphine, allyl chloride, solvent, and copper chloride are added to a first reactor, nitrogen gas is introduced, the mixture is stirred and heated, and then refluxed and kept warm to obtain a solution; the solution is distilled under reduced pressure to dryness, dissolved in ethyl acetate, filtered, cooled, recrystallized, and dried to obtain a solid; the solid, 3-[(3-acrylamidopropyl)dimethylammonium]propionate, acrylamide, 4-vinylpyridine, OP-10, sodium dodecyl sulfate, and water are added to a second reactor, and the mixture is stirred to obtain a mixed solution; an initiator is added to a first high-level tank, and a reducing agent is added to a second high-level tank; the initiator and reducing agent are added dropwise to the second reactor, and the temperature is raised simultaneously to granulate the product. The invention patent with publication number CN118496488A and classification number C08 discloses a method for preparing an antibacterial waterborne polyester. The preparation method includes the following steps: S1. Under nitrogen atmosphere, diethylene glycol and 1,6-hexanediol are added to a reaction vessel, stirred and heated to 60-80℃, then terephthalic acid and the catalyst di-n-butyltin oxide are added, and the temperature is gradually increased until the solid acid value is less than 2; S2-S5; S6. Nitrogen atmosphere is purged into a dilution vessel, ethylene glycol butyl ether and propylene glycol methyl ether are added, preheated to 60-80℃, stirred at 55-60 r / min, and the material in the reaction vessel is transferred to the dilution vessel. During the dilution process, the dilution temperature is maintained at 80-100℃. After dilution, the solid content and viscosity are tested and found to be qualified, and the material is discharged at 50-55℃ to obtain an antibacterial waterborne polyester.

[0004] However, the aforementioned macromolecular polymer-type bactericides are not biodegradable and can cause significant pollution if they remain in oilfield water injection systems for extended periods. Summary of the Invention

[0005] This invention solves the problem that traditional oilfield polymer-type bactericides (especially polyester-based bactericides) have low water solubility and lack biodegradability.

[0006] The technical solution of this invention is: a method for preparing a biodegradable bactericide for oil fields.

[0007] Step A: Add N,N-dimethylformamide, N-Boc-serine alcohol, 1,8-bis(butyramic acid)-3,6-dioxaoctane, and p-toluenesulfonic acid to the reaction vessel. Stir the reaction at 75-90℃ for 8-12 hours. Distill the solution under reduced pressure, wash with ethanol, and dry to obtain Boc amino polyester. The reaction formula is as follows:

[0008]

[0009] Step B: Add an ethyl acetate solution of hydrochloric acid and Boc aminopolyester to the reaction vessel. Stir the reaction at 20-30℃ for 5-8 hours. Distill the solution under reduced pressure, wash successively with saturated sodium bicarbonate and ethanol, and dry to obtain aminopolyester. The reaction formula is:

[0010]

[0011] Step C: Add water, aminopolyester, and glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir the reaction, heat the solution to evaporate, precipitate a large amount of precipitate, filter, wash with ethanol, and dry to obtain a biodegradable bactericide for oilfield use. The reaction formula is:

[0012]

[0013] Preferably, in step A, the ratio of N-Boc-serine alcohol, 1,8-bis(butyramic acid)-3,6-dioxaoctane, and p-toluenesulfonic acid is 1 mol: (0.9-1.1) mol: (0.04-0.05) mol.

[0014] Preferably, in step C, the ratio of amino polyester to glycidyl dimethyl dodecyl ammonium chloride is 1 g: (0.6-0.9) g.

[0015] Preferably, in step C, the reaction temperature is 55-70℃ and the reaction time is 18-24h.

[0016] Preferably, in step C, the preparation method of 1,8-bis(butyramic acid)-3,6-dioxaoctane is as follows: N,N-dimethylformamide solvent and succinic anhydride are added to a reaction vessel, followed by 1,8-diamino-3,6-dioxaoctane and ethyl acetate as a co-solvent. The mixture is stirred at 30-45°C for 6-10 hours. A saturated sodium chloride solution is added, and the mixture is extracted three times with ethyl acetate. The organic phases are combined, dried with anhydrous sodium sulfate, filtered, and the filtrate is distilled under reduced pressure, washed with petroleum ether, and dried to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane. The reaction formula is:

[0017]

[0018] Preferably, the ratio of succinic anhydride to 1,8-diamino-3,6-dioxaoctane is (2.6-3.2) mol: 1 mol.

[0019] Preferably, the ratio of N,N-dimethylformamide solvent to ethyl acetate co-solvent is 1L:(0.2-0.3)L.

[0020] Technical effects of the present invention: The present invention involves a ring-opening reaction of succinic anhydride with 1,8-diamino-3,6-dioxaoctane to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane, which is then subjected to esterification polymerization with N-Boc-serine alcohol and the Boc protecting group is removed to obtain an amino polyester. Finally, the amino group of the side chain reacts with the epoxy group of glycidyl dimethyl dodecyl ammonium chloride to obtain a biodegradable bactericide for oil fields.

[0021] The bactericide of the present invention has a large number of quaternary ammonium salt antibacterial groups in its side chain, which have strong bactericidal properties. At the same time, the main chain contains hydrophilic ether bonds and multiple hydrophilic amide bonds, which significantly improves the hydrophilicity and water solubility of the polyester-based bactericide. This is beneficial to improving the dispersibility and surface activity of the bactericide in oilfield water, enhancing the adsorption of the bactericide to bacterial cells, and allowing the bactericide to fully contact the bacterial cells, thereby better exerting the bactericidal properties of the bactericide.

[0022] The biodegradable bactericide for oilfields of this invention is a macromolecular polymer with better heat resistance. Even after high-temperature heat treatment, it maintains the structural stability of its molecular chain, is not easily thermally decomposed, and still exhibits a good bactericidal rate. Furthermore, the polymer backbone contains a large number of ester groups, resulting in strong hydrolysis and thus the bactericide exhibits excellent biodegradability, making it green, environmentally friendly, and with low pollution. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise stated, the raw materials and reagents used in the present invention below are commercially available products, or can be prepared by known methods.

[0024] Example 1

[0025] (1) Add 1500 mL of N,N-dimethylformamide solvent and 140 mmol of succinic anhydride to the reaction vessel, then add 50 mmol of 1,8-diamino-3,6-dioxaoctane and 400 mL of ethyl acetate as a co-solvent. Stir the reaction at 30 °C for 10 h, add saturated sodium chloride solution, and extract with ethyl acetate three times. Combine the organic phases, dry with anhydrous sodium sulfate, filter, distill under reduced pressure, wash with petroleum ether, and dry to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane.

[0026] (2) Add 300 mL of N,N-dimethylformamide, 20 mmol of N-Boc-serine alcohol, 20 mmol of 1,8-bis(butyramic acid)-3,6-dioxaoctane and 0.8 mmol of p-toluenesulfonic acid to the reaction vessel, stir and react at 80 °C for 8 h, distill under reduced pressure, wash with ethanol and dry to obtain Boc amino polyester.

[0027] (3) Add 800 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 4 mol / L and 40 g of Boc amino polyester to the reaction vessel. Stir the reaction at 30 °C for 5 h. Distill the solution under reduced pressure, wash it with saturated sodium bicarbonate and ethanol in sequence, and dry it to obtain amino polyester.

[0028] (4) Add 2L of water, 40g of amino polyester and 24g of glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir and react at 55℃ for 18h, heat the solution to evaporate, precipitate a large amount of precipitate, filter, wash with ethanol, dry, and obtain a biodegradable bactericide for oil fields.

[0029] Example 2

[0030] (1) Add 1500 mL of N,N-dimethylformamide solvent and 130 mmol of succinic anhydride to the reaction vessel, then add 50 mmol of 1,8-diamino-3,6-dioxaoctane and 300 mL of ethyl acetate as a co-solvent. Stir the reaction at 45 °C for 8 h, add saturated sodium chloride solution, and extract with ethyl acetate 3 times. Combine the organic phases, dry with anhydrous sodium sulfate, filter, distill under reduced pressure, wash with petroleum ether, and dry to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane.

[0031] (2) Add 400 mL of N,N-dimethylformamide, 20 mmol of N-Boc-serine alcohol, 22 mmol of 1,8-bis(butyramic acid)-3,6-dioxane and 1 mmol of p-toluenesulfonic acid to the reaction vessel, stir and react at 75 °C for 12 h, distill the solution under reduced pressure, wash with ethanol and dry to obtain Boc amino polyester.

[0032] (3) Add 800 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 4 mol / L and 40 g of Boc amino polyester to the reaction vessel. Stir the reaction at 25 °C for 8 h. Distill the solution under reduced pressure, wash it with saturated sodium bicarbonate and ethanol in sequence, and dry it to obtain amino polyester.

[0033] (4) Add 2L of water, 40g of amino polyester and 36g of glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir and react at 70℃ for 18h, heat the solution to evaporate, precipitate a large amount of precipitate, filter, wash with ethanol, dry, and obtain a biodegradable bactericide for oil fields.

[0034] Example 3

[0035] (1) Add 1500 mL of N,N-dimethylformamide solvent and 160 mmol of succinic anhydride to the reaction vessel, then add 50 mmol of 1,8-diamino-3,6-dioxaoctane and 450 mL of ethyl acetate as a co-solvent. Stir the reaction at 45 °C for 6 h, add saturated sodium chloride solution, and extract with ethyl acetate 3 times. Combine the organic phases, dry with anhydrous sodium sulfate, filter, distill under reduced pressure, wash with petroleum ether, and dry to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane.

[0036] (2) Add 400 mL of N,N-dimethylformamide, 20 mmol of N-Boc-serine alcohol, 18 mmol of 1,8-bis(butyramic acid)-3,6-dioxaoctane and 0.8 mmol of p-toluenesulfonic acid to the reaction vessel, stir and react at 90 °C for 8 h, distill under reduced pressure, wash with ethanol and dry to obtain Boc amino polyester.

[0037] (3) Add 800 mL of ethyl acetate solution of hydrochloric acid with a molar concentration of 4 mol / L and 40 g of Boc amino polyester to the reaction vessel. Stir the reaction at 20 °C for 8 h. Distill the solution under reduced pressure, wash it with saturated sodium bicarbonate and ethanol in sequence, and dry it to obtain amino polyester.

[0038] (4) Add 2L of water, 40g of amino polyester and 30g of glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir and react at 60℃ for 24h, heat the solution to evaporate, precipitate a large amount of precipitate, filter, wash with ethanol, dry, and obtain a biodegradable bactericide for oil fields.

[0039] Comparative Example 1

[0040] (1) Add 300 mL of N,N-dimethylformamide, 20 mmol of N-Boc-serine alcohol, 20 mmol of adipic acid, and 0.8 mmol of p-toluenesulfonic acid to the reaction vessel, stir and react at 80 °C for 8 h, distill under reduced pressure, wash with ethanol, and dry to obtain Boc amino polyester.

[0041] (2) Add 40g of Boc amino polyester to the reaction vessel in an ethyl acetate solution of hydrochloric acid with a molar concentration of 4mol / L. Stir the reaction at 30℃ for 5h. Distill the solution under reduced pressure, wash it with saturated sodium bicarbonate and ethanol in sequence, and dry it to obtain amino polyester.

[0042] (3) Add 2L of water, 40g of amino polyester and 24g of glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir and react at 55℃ for 18h, heat the solution to evaporate, precipitate a large amount of precipitate, filter, wash with ethanol, dry, and obtain a biodegradable bactericide for oil fields.

[0043] Comparative Example 2

[0044] (1) Add 300 mL of N,N-dimethylformamide, 20 mmol of 1,3-propanediol, 20 mmol of 1,8-bis(butyramic acid)-3,6-dioxaoctane (prepared in the same way as in Example 1), and 0.8 mmol of p-toluenesulfonic acid to the reaction vessel, stir and react at 80 °C for 8 h, distill under reduced pressure, wash with ethanol, and dry to obtain polyester.

[0045] (2) Add 2L of water, 40g of polyester and 24g of glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir and react at 55℃ for 18h, heat the solution to evaporate, and a large amount of precipitate is precipitated. After filtration, wash with ethanol and dry to obtain a biodegradable bactericide for oil fields.

[0046] A biodegradable bactericide for oilfield use was added to distilled water to prepare solutions of different mass concentrations. The solutions were stirred at 25°C for 10 minutes and allowed to stand for 1 hour. The state of the solutions was then observed. The results are shown in Table 1.

[0047] Table 1. Water solubility test of bactericides

[0048]

[0049] As shown in Table 1, the biodegradable bactericides for oilfields prepared in Examples 1-3 have excellent water solubility at a mass concentration of 0.05-10 g / L. This is because 1,8-bis(butyramic acid)-3,6-dioxaoctane contains hydrophilic ether bonds and multiple hydrophilic amide bonds. After esterification polymerization with N-Boc-serine alcohol, the ether bonds and amide bonds are introduced into the main chain of the polyester, which significantly improves the hydrophilicity and water solubility of the polyester-based bactericide.

[0050] Comparative Example 1 uses N-Boc-serine alcohol and adipic acid to polymerize, and the resulting polyester-based bactericide does not contain hydrophilic ether bonds and amide bonds, has poor water solubility, and easily forms suspensions and precipitates in water.

[0051] Comparative Example 2 was polymerized with 1,3-propanediol and 1,8-bis(butyramic acid)-3,6-dioxaoctane, and the resulting polyester-based bactericide contained hydrophilic ether bonds and amide bonds in its main chain and had good water solubility.

[0052] Weigh 10g (denoted as m) of the bactericide and add it to 1L of PBS buffer solution. Stir at 30℃ for 7-28 days, freeze dry to remove water, wash with ethanol, dry, weigh (denoted as m1), and calculate the weight loss rate W.

[0053] W = (m - m1) / m × 100%. The higher the weight loss rate, the better the degradation performance. The results are shown in Table 2.

[0054] Table 2. Test of weight loss rate of fungicides

[0055]

[0056] Tests in Examples 1-3 showed that the bactericides exhibited high weight loss rates and excellent degradability, primarily due to their good water solubility. Furthermore, the bactericides contain a large number of ester groups in their polymer backbone, resulting in strong hydrolysis and thus demonstrating excellent degradability.

[0057] The bactericide in Comparative Example 1 contains a large number of ester groups in its main chain and has strong hydrolytic properties, but its weight loss rate is lower than that of the other examples. This is mainly because the bactericide has low water solubility, and the polyester molecular chain cannot fully contact water, resulting in poor hydrolytic performance.

[0058] Bactericidal performance test: A bactericide solution with a mass concentration of 50 mg / L was prepared by adding a bactericide to distilled water. Following the method described in SY-T 5890-93, the bactericide solution was tested for its effectiveness against sulfate-reducing bacteria SRB (concentration 6.2 × 10⁻⁶). 5 (Cells / mL), iron bacteria FB (concentration 8.5×10⁻⁶) 4 (CFU / mL) and heterotrophic bacteria TGB (concentration 1.4 × 10⁻⁶) 7 The sterilization rate is (number per mL).

[0059] The bactericide was placed in an oven and heat-treated at 120℃ for 48 hours, then cooled, and its bactericidal performance was tested. The results are shown in Table 3.

[0060] Table 3. Tests on the bactericidal and heat-resistant properties of bactericides.

[0061]

[0062] Comparative Example 3 used glycidyl dimethyl dodecyl ammonium chloride as a bactericide.

[0063] As shown in Table 2, the polyester-based bactericides in Examples 1-3 contain a large number of quaternary ammonium salt antibacterial groups in their side chains, exhibiting high bactericidal rates against sulfate-reducing bacteria, iron bacteria, and heterotrophic bacteria. Furthermore, as a macromolecular polymer, the bactericide exhibits better heat resistance; even after high-temperature heat treatment, it maintains the structural stability of its molecular chains, is not easily thermally decomposed, and still demonstrates excellent bactericidal rates. Simultaneously, the polyester-based bactericide has excellent water solubility, which can improve its dispersibility and surface activity in oilfield water, enhance the adsorption between the bactericide and bacterial cells, and ensure sufficient contact between the bactericide and bacterial cells, thus better exerting the bactericidal performance.

[0064] The polyester-based bactericide in Comparative Example 1 has poor water solubility, easily forming suspensions and precipitates in water. Its adsorption to bacterial cells is low, preventing sufficient contact with the bacteria and resulting in a significantly lower bactericidal rate than in Example 1. However, as a macromolecular polymer, this polyester-based bactericide has better heat resistance; after high-temperature heat treatment, the decrease in bactericidal rate is very small.

[0065] Comparative Example 2 uses 1,3-propanediol and 1,8-bis(butyramic acid)-3,6-dioxaoctane for polymerization. The resulting polyester does not contain amino groups and cannot react with the epoxy groups of glycidyl dimethyl dodecyl ammonium chloride. The resulting bactericide does not contain quaternary ammonium salt antibacterial groups and does not show bactericidal rate against sulfate-reducing bacteria and other bacteria.

[0066] Comparative Example 3, using glycidyl dimethyl dodecyl chloride as a bactericide, showed a good bactericidal rate against sulfate-reducing bacteria. However, as a small molecule compound, glycidyl dimethyl dodecyl chloride has a low thermal decomposition temperature and poor heat resistance. After high-temperature heat treatment, it is prone to thermal decomposition, which seriously affects its bactericidal performance and significantly reduces the bactericidal rate.

[0067] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A method for preparing a biodegradable bactericide for oilfield use, characterized in that, The preparation method is as follows: Step A: Add N,N-dimethylformamide, N-Boc-serine alcohol, 1,8-bis(butyramic acid)-3,6-dioxane, and p-toluenesulfonic acid to the reaction vessel, stir the reaction, distill the solution under reduced pressure, wash with ethanol, and dry to obtain Boc amino polyester. The structural formula of 1,8-bis(butyramic acid)-3,6-dioxaoctane is as follows: ； Step B: Add ethyl acetate solution of hydrochloric acid and Boc amino polyester to the reaction vessel, stir and react at 20-30℃ for 5-8 hours, distill under reduced pressure, wash and dry to obtain amino polyester. Step C: Add water, amino polyester, and glycidyl dimethyl dodecyl ammonium chloride to the reaction vessel, stir the reaction, heat the solution to evaporate, precipitate out, filter, wash, and dry to obtain a biodegradable bactericide for oil fields.

2. The method for preparing the biodegradable bactericide for oilfield use according to claim 1, characterized in that, In step A, the ratio of N-Boc-serine alcohol, 1,8-bis(butyramic acid)-3,6-dioxaoctane, and p-toluenesulfonic acid is 1 mol: (0.9-1.1) mol: (0.04-0.05) mol.

3. The method for preparing the biodegradable bactericide for oilfield use according to claim 1, characterized in that, In step A, the reaction temperature is 75-90℃ and the reaction time is 8-12h.

4. The method for preparing the biodegradable bactericide for oilfields according to claim 1, characterized in that, In step C, the ratio of amino polyester to glycidyl dimethyl dodecyl ammonium chloride is 1 g: (0.6-0.9) g.

5. The method for preparing the biodegradable bactericide for oilfield use according to claim 1, characterized in that, In step C, the reaction temperature is 55-70℃ and the reaction time is 18-24h.

6. The method for preparing the biodegradable bactericide for oilfield use according to claim 2, characterized in that, In step C, the preparation method of 1,8-bis(butyramic acid)-3,6-dioxaoctane is as follows: N,N-dimethylformamide solvent and succinic anhydride are added to the reaction vessel, and then 1,8-diamino-3,6-dioxaoctane and ethyl acetate co-solvent are added. After the reaction, extraction, washing and drying are performed to obtain 1,8-bis(butyramic acid)-3,6-dioxaoctane.

7. The method for preparing the biodegradable bactericide for oilfield use according to claim 6, characterized in that, The ratio of succinic anhydride to 1,8-diamino-3,6-dioxane is (2.6-3.2) mol: 1 mol.

8. The method for preparing the biodegradable bactericide for oilfield use according to claim 6, characterized in that, The ratio of N,N-dimethylformamide solvent to ethyl acetate co-solvent is 1L:(0.2-0.3)L.

9. The method for preparing the biodegradable bactericide for oilfield use according to claim 6, characterized in that, The reaction is carried out at a temperature of 30-45℃ for 6-10 hours.

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