Dual quaternary ammonium salts, processes for their preparation and use

Abstract

The present application relates to the technical field of oil field chemistry, and is a kind of double quaternary ammonium salt and its preparation method and application, the double quaternary ammonium salt is prepared according to the following steps: p-dimethylaminobenzaldehyde and dihalogenated hydrocarbon are added to solvent, reflux reaction, and the reaction product is obtained after concentration and recrystallization to obtain double quaternary ammonium salt.The double quaternary ammonium salt of the present application is used as an oil field bactericide with high efficiency and excellent temperature resistance, and the bactericidal rate is as high as 99.8% or more, far exceeding conventional bactericides;After high temperature treatment at 120 DEG C, the bactericidal rate can still be maintained at 98.7% or more, and the performance is stable.The double quaternary ammonium salt is not easy to produce drug resistance through the synergistic effect of benzene ring, aldehyde group and double quaternary ammonium salt, and the preparation process is simple, the cost is low, and the problem of high temperature oil reservoir sterilization is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically a quaternary ammonium salt, its preparation method, and its application. Background Technology

[0002] In oilfield development and produced fluid treatment, the high temperature, high salinity, and nutrient-rich environment of oil reservoirs provide favorable conditions for the reproduction of harmful microorganisms such as sulfate-reducing bacteria (SRB), thallium bacteria (TGB), and iron bacteria (FB). The proliferation of these microorganisms can lead to a series of serious problems, including metal equipment corrosion, formation pore blockage, hydrogen sulfide contamination, and decreased crude oil quality, directly impacting oilfield production efficiency and operational safety. Specifically, hydrogen sulfide produced by SRB metabolism significantly exacerbates corrosion of tubing and casing, posing safety hazards; the viscous substances secreted by TGB easily form biofilms, clogging water injection systems and formation channels, causing increased water injection pressure and decreased oil displacement efficiency; and iron-based precipitation produced by FB oxidation further exacerbates reservoir blockage. Therefore, developing efficient, stable bactericides suitable for complex reservoir conditions is a key technological requirement for ensuring the long-term safe and efficient development of oilfields.

[0003] Currently, commonly used bactericides in oilfields are mainly divided into inorganic bactericides and organic bactericides. Inorganic bactericides (such as hypochlorite, chlorine dioxide, etc.) have a fast bactericidal speed, but they have defects such as poor stability, strong corrosiveness, and short effective period. Among organic bactericides, quaternary ammonium salts have become mainstream products due to their broad bactericidal spectrum, convenient use, and moderate cost, but they have revealed obvious shortcomings in long-term application: (1) long-term single use can easily lead to drug resistance in microorganisms, and the bactericidal effect will continue to decline; (2) poor temperature resistance, and easy decomposition and failure under high temperature reservoir conditions; (3) single action site, and limited long-term bactericidal ability. In recent years, quaternary phosphate bactericides have improved in stability, but they still have problems such as complex synthesis routes, high raw material costs, and easy failure under high salt environment, making it difficult to fully meet the long-term bactericidal needs of complex oilfields with high temperature, high salt, and high mineralization.

[0004] Chinese patent document CN114957525A discloses a bactericide for oilfield wastewater treatment and its synthesis method. 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, an initiator is added, the temperature is raised to 60-70°C, and the reaction continues 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 to obtain the bactericide. However, its molecular skeleton mainly relies on carbon-phosphorus bonds and conventional polymerization structures, lacking a rigid structure capable of resisting extreme high temperatures. In high-temperature and high-pressure formation environments of 120°C, this agent is prone to molecular chain breakage or deactivation of active groups.

[0005] Existing oilfield bactericides struggle to simultaneously achieve a combination of high-efficiency sterilization, high-temperature resistance, low resistance to drug development, simple preparation processes, and low cost. Therefore, developing a novel bactericide with multiple active groups, stable structure, and strong environmental adaptability holds significant engineering value and application prospects for addressing microbial hazards in oilfields and improving development efficiency. Summary of the Invention

[0006] This invention provides a quaternary ammonium salt and its preparation method, which overcomes the shortcomings of the prior art and can effectively solve the problems of existing oilfield bactericides, such as easy development of drug resistance, poor temperature resistance, insufficient bactericidal efficiency, and high preparation cost.

[0007] One of the technical solutions of this invention is achieved through the following measures: a bisquaternary ammonium salt having the following chemical structure: Where n is an integer from 3 to 6; X is the element chlorine and / or bromine.

[0008] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The aforementioned quaternary ammonium salts are used as bactericides in oil fields.

[0009] The above-mentioned quaternary ammonium salts were prepared according to the following steps: p-Dimethylaminobenzaldehyde and dihalohydrocarbons were added to a solvent and refluxed. The reaction product was concentrated and recrystallized to obtain a bisquaternary ammonium salt.

[0010] The molar ratio of p-dimethylaminobenzaldehyde to dihalohydrocarbon mentioned above is 1.1 to 1.2:1.

[0011] The above reflux reaction was carried out under inert gas protection.

[0012] The reflux reaction temperature is 80°C to 90°C.

[0013] The reflux reaction time is 24 to 48 hours.

[0014] The solvent mentioned above is anhydrous ethanol.

[0015] The general structural formula of the above-mentioned dihalohydrocarbons is X-(CH2). n -X, where n is an integer from 3 to 6, and X is the element chlorine and / or bromine.

[0016] The second technical solution of the present invention is achieved through the following measures: a method for preparing a bis-quaternary ammonium salt, comprising the following steps: p-Dimethylaminobenzaldehyde and dihalohydrocarbons were added to a solvent and refluxed. The reaction product was concentrated and recrystallized to obtain a bisquaternary ammonium salt.

[0017] The third technical solution of the present invention is achieved through the following measures: the application of a quaternary ammonium salt as a bactericide for oil fields.

[0018] This invention provides a bis-quaternary ammonium salt, its preparation method, and its application. This bis-quaternary ammonium salt, as a bactericide for oilfields, combines highly efficient bactericidal activity with excellent temperature resistance. Its bactericidal rate reaches over 99.8%, far exceeding that of conventional bactericides. Even after high-temperature treatment at 120℃, the bactericidal rate remains above 98.7%, demonstrating stable performance. This bis-quaternary ammonium salt, through the synergistic effect of multiple active groups such as benzene rings, aldehyde groups, and the bis-quaternary ammonium salt itself, is less prone to drug resistance. Furthermore, its preparation process is simple and low-cost, effectively solving the problem of bactericidal activity in high-temperature oil reservoirs. Detailed Implementation

[0019] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0020] The present invention will be further described below with reference to embodiments: Example 1: This bisquaternary ammonium salt has the following chemical structure: Where n is an integer from 3 to 6; X is the element chlorine and / or bromine.

[0021] Example 2: As an optimization of the above example, the quaternary ammonium salt is used as a bactericide for oil fields.

[0022] Example 3: As an optimization of the above examples, the bisquaternary ammonium salt was prepared according to the following steps: p-Dimethylaminobenzaldehyde and dihalohydrocarbons were added to a solvent and refluxed. The reaction product was concentrated and recrystallized to obtain a bisquaternary ammonium salt.

[0023] Example 4: As an optimization of the above example, the molar ratio of p-dimethylaminobenzaldehyde to dihalohydrocarbon is 1.1 to 1.2:1.

[0024] Example 5: As an optimization of the above examples, the reflux reaction is carried out under inert gas protection.

[0025] Example 6: As an optimization of the above example, the reflux reaction temperature is 80°C to 90°C.

[0026] Example 7: As an optimization of the above examples, the reflux reaction time is 24h to 48h.

[0027] Example 8: As an optimization of the above examples, the solvent is anhydrous ethanol.

[0028] Example 9: As an optimization of the above examples, the general structural formula of the dihalohydrocarbon is X-(CH2). n -X, where n is an integer from 3 to 6, and X is the element chlorine and / or bromine.

[0029] The bisquaternary ammonium salt of this invention is prepared by quaternization using anhydrous ethanol as solvent and p-dimethylaminobenzaldehyde and dihalohydrocarbons as raw materials. The chemical reaction process for preparation is as follows: Where n is an integer from 3 to 6; X is the element chlorine and / or bromine.

[0030] Example 10: Application of this quaternary ammonium salt as a bactericide for oil fields.

[0031] Example 11: The preparation process of this bisquaternary ammonium salt is as follows: In a 250 mL three-necked flask equipped with a stirrer, reflux condenser, and nitrogen inlet, 0.11 mol of p-dimethylaminobenzaldehyde, 0.1 mol of 1,4-dibromobutane, and 55 mL of anhydrous ethanol were added. Nitrogen was bubbled through for 15 min to remove oxygen, and the mixture was heated to 90 °C and refluxed with stirring for 48 h. After the reaction was complete, the anhydrous ethanol was removed by vacuum distillation. The reaction product was recrystallized from ethyl acetate and dried under vacuum to give a bisquaternary ammonium salt in 95.3% yield.

[0032] Example 12: The preparation process of this bisquaternary ammonium salt is as follows: In a 250 mL three-necked flask equipped with a stirrer, reflux condenser, and nitrogen inlet, 0.11 mol of p-dimethylaminobenzaldehyde, 0.1 mol of 1,3-dichloropropane, and 50 mL of anhydrous ethanol were added. Nitrogen was bubbled through for 20 min to remove oxygen, and the mixture was heated to 85 °C and refluxed with stirring for 30 h. After the reaction was complete, the anhydrous ethanol was removed by vacuum distillation. The reaction product was recrystallized from ethyl acetate and dried under vacuum to give a bisquaternary ammonium salt with a yield of 93.7%.

[0033] Example 13: The preparation process of this bisquaternary ammonium salt is as follows: In a 250 mL three-necked flask equipped with a stirrer, reflux condenser, and nitrogen inlet, 0.12 mol of p-dimethylaminobenzaldehyde, 0.1 mol of 1,5-dibromopentane, and 60 mL of anhydrous ethanol were added. Nitrogen was bubbled through for 15 min to remove oxygen, and the mixture was heated to 80 °C and refluxed with stirring for 36 h. After the reaction was complete, the anhydrous ethanol was removed by vacuum distillation. The reaction product was recrystallized from ethyl acetate and dried under vacuum to give a bisquaternary ammonium salt with a yield of 95.8%.

[0034] Example 14: The preparation process of this bis-quaternary ammonium salt is as follows: In a 250 mL three-necked flask equipped with a stirrer, reflux condenser, and nitrogen inlet, 0.11 mol of p-dimethylaminobenzaldehyde, 0.1 mol of 1,6-dichlorohexane, and 50 mL of anhydrous ethanol were added. Nitrogen was bubbled through for 20 min to remove oxygen, and the mixture was heated to 90 °C and refluxed with stirring for 48 h. After the reaction was complete, the anhydrous ethanol was removed by vacuum distillation. The reaction product was recrystallized from ethyl acetate and dried under vacuum to give a bisquaternary ammonium salt with a yield of 94.9%.

[0035] Test Example 1: Sterilization Performance Test According to the standard "Q / SY 49-2010 Technical Requirements for Bactericides Used in Oilfields", relevant bactericidal tests were conducted. Reinjected water from a certain area of ​​an oilfield was used as the test subject, and the conventional oilfield bactericide 1227 (dodecyl dimethyl benzyl ammonium chloride) was used as a comparison. The dosage of the quaternary ammonium salt prepared in Examples 11 to 14 and the conventional bactericide 1227 was 50 mg / L. The bactericidal performance was evaluated, and the results are shown in Table 1 (SRB is sulfate-reducing bacteria, TGB is saprophytic bacteria, and FB is iron bacteria).

[0036] Table 1 .

[0037] The bactericidal performance test results showed that the quaternary ammonium salts prepared in the four examples all exhibited extremely high bactericidal rates against the three major harmful bacteria, all exceeding 99.8%, with several examples achieving 100% bactericidal rates against specific bacteria. This indicates that the bactericide possesses broad-spectrum and highly efficient bactericidal capabilities. In contrast, conventional bactericide 1227, under the same conditions, showed bactericidal rates below 90% against all three bacteria. The bactericidal effect of the quaternary ammonium salt of this invention is significantly superior because it possesses active groups such as benzene rings, aldehyde groups, and quaternary ammonium salts, enabling highly efficient and broad-spectrum killing of harmful microorganisms in oil fields even at low dosages, effectively reducing the required dosage.

[0038] Test Example 2: Evaluation of Temperature Resistance The quaternary ammonium salts prepared in Examples 11 to 14 and conventional bactericide 1227 were prepared into a 1000 mg / L solution using distilled water. The solution was then heat-treated at 120 °C for 24 h. The bactericidal effect of each sample after 24 h of heat treatment was tested to evaluate the temperature resistance of the bactericide. The results are shown in Table 2 (SRB is sulfate-reducing bacteria, TGB is saprophytic bacteria, and FB is iron bacteria).

[0039] Table 2 .

[0040] The results of the temperature resistance evaluation show that after heat treatment at 120℃ for 24 hours, the bactericidal rate of conventional bactericide 1227 dropped sharply from nearly 90% at room temperature to about 60%. This indicates that its molecular structure has decomposed or deactivated at high temperatures, and it is completely unable to meet the bactericidal requirements of high-temperature oil reservoirs. In contrast, the quaternary ammonium salt of this invention, after undergoing the same high-temperature test, still maintained a bactericidal rate of over 98.7% against the three major harmful bacteria, with only a slight decrease in bactericidal effect, proving that its molecular structure has extremely high thermal stability.

[0041] In summary, this invention provides a bis-quaternary ammonium salt and its preparation method. Its molecular structure simultaneously contains multiple active groups, including a benzene ring, an aldehyde group, and a quaternary ammonium salt. As a bactericide for oilfields, it possesses multiple bactericidal sites and a unique mechanism of action, exhibiting outstanding killing effects against harmful microorganisms such as SRB and TGB in oilfields, and is less prone to developing resistance. Furthermore, this bis-quaternary ammonium salt has the advantage of high-temperature resistance, maintaining extremely high bactericidal activity even after treatment at 120℃, making it suitable for complex reservoir conditions and an ideal choice for solving the problem of microbial hazards in high-temperature oil reservoirs. Moreover, its preparation process is simple, the conditions are mild, and the yield is high, making it suitable for industrial production, with significant technical advantages and broad application prospects.

[0042] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A bisquaternary ammonium salt, characterized in that... It has the following chemical structure: Where n is an integer from 3 to 6; X is the element chlorine and / or bromine.

2. The bisquaternary ammonium salt according to claim 1, characterized in that... Diquaternary ammonium salts are used as bactericides in oil fields.

3. The bisquaternary ammonium salt according to claim 1 or 2, characterized in that... The bisquaternary ammonium salt is prepared according to the following steps: p-Dimethylaminobenzaldehyde and dihalohydrocarbons were added to a solvent and refluxed. The reaction product was concentrated and recrystallized to obtain a bisquaternary ammonium salt.

4. The bisquaternary ammonium salt according to claim 3, characterized in that... The molar ratio of p-dimethylaminobenzaldehyde to dihalohydrocarbon is 1.1 to 1.2:

1.

5. The bisquaternary ammonium salt according to claim 3 or 4, characterized in that... The reflux reaction is carried out under inert gas protection.

6. The bisquaternary ammonium salt according to claim 3 or 4, characterized in that... The reflux reaction temperature is 80℃ to 90℃, and the reflux reaction time is 24h to 48h.

7. The bisquaternary ammonium salt according to claim 3 or 4, characterized in that... The solvent is anhydrous ethanol.

8. The bisquaternary ammonium salt according to claim 3 or 4, characterized in that... The general structural formula for dihalohydrocarbons is X-(CH2). n -X, where n is an integer from 3 to 6, and X is the element chlorine and / or bromine.

9. A method for preparing a bis-quaternary ammonium salt according to any one of claims 1 to 8, characterized in that... Includes the following steps: p-Dimethylaminobenzaldehyde and dihalohydrocarbons were added to a solvent and refluxed. The reaction product was concentrated and recrystallized to obtain a bisquaternary ammonium salt.

10. The application of a quaternary ammonium salt according to any one of claims 1 to 8 as a bactericide for oil fields.

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