Oilfield produced water bactericide and its synthesis method and application

Abstract

The present invention belongs to the technical field of sewage treatment, and particularly relates to a kind of oilfield produced water bactericide and its synthesis method and application. The synthesis method is as follows: add water, 1,3-dimethyl-2-imidazolidinone, diethylamine, sodium cyanoborohydride into a four-necked flask, stir evenly, adjust pH with formic acid aqueous solution, stir and react for 1-3h at room temperature, cool, extract, combine extracts, and distill under reduced pressure to obtain a viscous solid; transfer the above-mentioned viscous solid to a four-necked flask with isopropanol, add dodecyl bromide, heat to reflux, and react to obtain a mixed solution; distill the above-mentioned mixture under reduced pressure to 70-75°C without distillate to obtain a viscous solid, recrystallize, and dry to obtain a product, i.e., a bactericide. The bactericide has the advantages of a wide source of raw materials, a simple synthesis process, a broad spectrum of bactericidal properties, and a low concentration and high efficiency. The bactericidal rate can reach 100% when the concentration is 15mg / L.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and particularly relates to an oilfield produced water bactericide and a synthesis method and application thereof. Background Art

[0002] At present, the oil layer pressure gradually decreases during the development of oil fields, and the crude oil production will also decrease. Therefore, it is necessary to take process measures to replenish the energy of the formation in time to keep the oil layer at a certain pressure. Water injection is the main mode of oil field development at present, and most oil fields in my country adopt this method. In the oil field water injection development system, there are many harmful bacteria and microorganisms, the most common of which are sulfate reducing bacteria (SRB), saprophytic bacteria (TGB) and iron bacteria (FB). The growth, metabolism and reproduction of these bacteria can cause corrosion and damage to drilling equipment, water injection pipelines and other metal materials, blockage of pipelines and water injection wells, reduce the pore permeability of the oil layer, hinder water injection oil production, and increase the water injection pressure, which directly affects the crude oil production. Especially with the development of secondary and tertiary oil recovery technology, the amount of water injected and produced in oil fields has continued to increase, and the application of polymer flooding has created favorable conditions for the reproduction of bacteria in the system, making the harm of bacteria increasingly serious.

[0003] Therefore, produced water must be sterilized before reinjection. There are many kinds of chemical agents used to kill or inhibit the growth of microorganisms. The extent of the killing effect on microorganisms varies depending on the toxicity of the chemical agent, the permeability into the cell and the type of microorganism. A chemical agent is toxic to a certain microorganism, but may have no effect on another microorganism. Some agents have a bactericidal effect at a slightly higher concentration, but at a certain low concentration, they have a stimulating effect on growth. Only by correctly selecting and using bactericides can the reproduction of harmful bacteria be effectively inhibited.

[0004] At present, the most commonly used fungicide in oil fields is dodecyl dimethyl benzyl ammonium chloride (1227), which is a single variety. Long-term use will cause bacteria to develop a certain degree of drug resistance, resulting in a significant decrease in the effectiveness of the agent.

[0005] CN104488874A discloses a composite bactericide for oilfield water injection system. The composite bactericide weight percentage composition is 70-80% of an aqueous solution with a mass fraction of benzalkonium chloride of 45-55%, 10-20% of an ethanol solution with a mass fraction of cetylpyridinium bromide of 25-35%, and 10-15% of a xylene solution with a mass fraction of tetrachloroisophthalonitrile of 18-22%. The composite bactericide for oilfield water injection system of the present invention has a strong bactericidal effect, can effectively remove sulfate-reducing bacteria, iron bacteria, and saprophytic bacteria in sewage, avoid bacteria from corroding and clogging pipeline equipment, and has the advantages of simple components, convenient preparation, fast and efficient, low cost, high bactericidal rate, low usage, and small side effects. However, the composite component has a large content of cetylpyridinium bromide, which has a large toxicity and causes environmental damage after use. Summary of the invention

[0006] The present invention aims to provide an oilfield produced water fungicide and its synthesis method and application in view of the deficiencies of the above-mentioned prior art. The fungicide has the advantages of wide raw material sources, simple synthesis process, broad-spectrum bactericidal effect, and high efficiency at low concentration. When the concentration is 15 mg / L, the bactericidal rate can reach 100%. At the same time, the fungicide of the present invention has a broad spectrum and can kill SRB, TGB and FB in oily wastewater.

[0007] One of the purposes of the present invention is to disclose an oilfield produced water bactericide, the molecular structure of the bactericide is as follows:

[0008]

[0009] Another object of the present invention is to disclose a method for synthesizing the above-mentioned oilfield produced water fungicide, the specific steps of which are as follows:

[0010] (1) Add water, 1,3-dimethyl-2-imidazolidinone, diethylamine, and sodium cyanoborohydride to a four-necked flask equipped with a reflux condenser, stir evenly, adjust the pH to 3-4 with a 10 wt % formic acid aqueous solution, stir and react at room temperature, then heat to 80-85° C., continue to react for 1-3 hours, cool to room temperature, extract twice with chloroform, combine the extracts and perform vacuum distillation to obtain a viscous solid;

[0011] (2) transferring the viscous solid to a four-necked flask with isopropanol, adding dodecyl bromide, heating to reflux, continuously adding isopropanol during the reflux process to maintain a substantially stable amount of the reaction solvent, and reacting to obtain a mixed solution;

[0012] (3) 70-80% of the isopropanol is removed from the mixed solution under reduced pressure, and the remaining concentrated solution is distilled under reduced pressure on a rotary evaporator until there is no distillate at 70-75° C. to obtain a viscous solid, which is recrystallized from ethyl acetate to obtain a light yellow solid, which is dried in an oven at 80-85° C. for 4-6 hours to obtain a product, i.e., a fungicide.

[0013] Preferably, based on 1 mol part of 1,3-dimethyl-2-imidazolidinone, the amounts of diethylamine and dodecyl bromide used are 0.9-1.5 mol parts and 2.5-4 mol parts, respectively; more preferably, based on 1 mol part of 1,3-dimethyl-2-imidazolidinone, the amounts of diethylamine and dodecyl bromide used are 1.1-1.4 mol parts and 3-4 mol parts, respectively.

[0014] Preferably, the mass ratio of water to 1,3-dimethyl-2-imidazolidinone in step (1) is 20-30:1.

[0015] Preferably, in step (1), the mass ratio of sodium cyanoborohydride to 1,3-dimethyl-2-imidazolidinone is 0.2-0.4:1.

[0016] Preferably, the stirring reaction time at room temperature in step (1) is 12-24 h; more preferably, the stirring reaction time at room temperature is 16-20 h.

[0017] Preferably, the mass ratio of chloroform to 1,3-dimethyl-2-imidazolidinone in step (1) is 30-40:1.

[0018] Preferably, the mass ratio of isopropanol to 1,3-dimethyl-2-imidazolidinone in step (2) is 40-60:1.

[0019] Preferably, the heating reflux time in step (2) is 24-48 hours; more preferably, the heating reflux time is 30-42 hours.

[0020] The reaction equation for the synthesis of the fungicide of the present invention is as follows:

[0021]

[0022] The third object of the present invention is to disclose the application of the above-mentioned fungicide in oilfield produced water fungicide.

[0023] The present invention belongs to a cationic bactericide, and has three quaternary ammonium salt functional groups in the molecule, which has a strong positive charge. The induction effect of three dodecane long-chain alkanes further strengthens the positive charge of the N atom. The bacterial surface is negatively charged and is easy to adsorb positively charged molecules. The quaternary ammonium cations are gathered on the cell wall through the effects of electrostatic force, hydrogen bond force and hydrophobic combination between surfactant molecules and protein molecules, producing a chamber resistance effect, thereby changing the permeability of the cell wall, resulting in bacterial growth being inhibited and dying. The bactericide molecules can also penetrate into the bacterial body, making the bacterial protein inactive.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The raw materials of the fungicide of the present invention are widely available and the synthesis process is simple;

[0026] (2) The bactericide of the present invention has a broad spectrum and can kill SRB, TGB and FB in oily wastewater;

[0027] (3) The fungicide of the present invention has the advantages of low concentration and high efficiency. When the concentration is 15 mg / L, the fungicide rate can reach 100%. DETAILED DESCRIPTION

[0028] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0029] The technical solution of the invention is further described below in conjunction with specific embodiments.

[0030] Embodiment 1:

[0031] (1) In a four-necked flask equipped with a reflux condenser, 114 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 45 mmol of diethylamine, and 1.14 g of sodium cyanoborohydride were added and stirred evenly. The pH was adjusted to 3 with a 10 wt % aqueous formic acid solution. The mixture was stirred and reacted at room temperature for 12 h. The mixture was then heated to 80° C. and continued to react for 1 h. The mixture was cooled to room temperature and extracted twice with 153 g of chloroform. The extracts were combined and distilled under reduced pressure to obtain a viscous solid.

[0032] (2) Transfer the above viscous solid to a four-necked flask with 228 g of isopropanol, add 125 mmol of dodecyl bromide, and heat to reflux for 24 h. During the reflux process, isopropanol is continuously added to maintain a basically stable amount of reaction solvent;

[0033] (3) 70% of the isopropanol was removed from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until there was no distillate at 70°C to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 80°C for 5 h to obtain the product fungicide A.

[0034] Embodiment 2:

[0035] (1) 171 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 75 mmol of diethylamine, and 2.28 g of sodium cyanoborohydride were added to a four-necked flask equipped with a reflux condenser, and the mixture was stirred evenly. The pH was adjusted to 4 with a 10 wt % aqueous formic acid solution, and the mixture was stirred and reacted at room temperature for 24 h. The mixture was then heated to 85° C. and the reaction was continued for 2 h. The mixture was cooled to room temperature, and extracted twice with 228 g of chloroform. The extracts were combined and distilled under reduced pressure to obtain a viscous solid.

[0036] (2) The viscous solid was transferred to a four-necked flask with 342 g of isopropanol, 200 mmol of dodecyl bromide was added, and the mixture was heated to reflux for 48 h. During the reflux process, isopropanol was continuously added to maintain a substantially stable amount of reaction solvent;

[0037] (3) 70-80% of the isopropanol was distilled off from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until there was no distillate at 72°C to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 85°C for 4 h to obtain the product fungicide B.

[0038] Embodiment 3:

[0039] (1) In a four-necked flask equipped with a reflux condenser, 136 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 50 mmol of diethylamine, and 1.4-4 were added, and the mixture was stirred at room temperature for 14 h, then heated to 85° C., and the reaction was continued for 3 h. The mixture was cooled to room temperature, and extracted twice with 179 g of chloroform. The extracts were combined and distilled under reduced pressure to obtain a viscous solid;

[0040] (2) The viscous solid was transferred to a four-necked flask with 252 g of isopropanol, 148 mmol of dodecyl bromide was added, and the mixture was heated to reflux for 28 h. During the reflux process, isopropanol was continuously added to maintain a substantially stable amount of the reaction solvent.

[0041] (3) 75% of the isopropanol was removed from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until there was no distillate at 75°C to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 82°C for 5 h to obtain the product fungicide C.

[0042] Embodiment 4:

[0043] (1) 161 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 70 mmol of diethylamine, and 2.02 g of sodium cyanoborohydride were added to a four-necked flask equipped with a reflux condenser, and the mixture was stirred evenly. The pH was adjusted to 4 with a 10 wt % aqueous formic acid solution, and the mixture was stirred and reacted at room temperature for 20 h. The mixture was then heated to 82° C. and the reaction was continued for 2 h. The mixture was cooled to room temperature, and extracted twice with 204 g of chloroform. The extracts were combined and distilled under reduced pressure to obtain a viscous solid.

[0044] (2) The viscous solid was transferred to a four-necked flask with 310 g of isopropanol, 180 mmol of dodecyl bromide was added, and the mixture was heated to reflux for 44 h. During the reflux process, isopropanol was continuously added to maintain a substantially stable amount of the reaction solvent.

[0045] (3) 80% of the isopropanol was distilled off from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until no distillate was produced at 70° C. to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 82° C. for 6 h to obtain the product fungicide D.

[0046] Embodiment 5:

[0047] (1) 142 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 58 mmol of diethylamine, and 1.72 g of sodium cyanoborohydride were added to a four-necked flask equipped with a reflux condenser, and the mixture was stirred evenly. The pH was adjusted to 4 with a 10 wt % aqueous formic acid solution, and the mixture was stirred and reacted at room temperature for 16 h. The mixture was then heated to 83° C. and the reaction was continued for 1 h. The mixture was cooled to room temperature, and extracted twice with 182 g of chloroform. The extracts were combined and distilled under reduced pressure to obtain a viscous solid.

[0048] (2) The viscous solid was transferred to a four-necked flask with 271 g of isopropanol, 161 mmol of dodecyl bromide was added, and the mixture was heated to reflux for 32 h. During the reflux process, isopropanol was continuously added to maintain a substantially stable amount of the reaction solvent.

[0049] (3) 72% of the isopropanol was distilled off from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until there was no distillate at 75°C to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 80°C for 5 h to obtain the product fungicide E.

[0050] Embodiment 6:

[0051] (1) Add 153 g of water, 50 mmol of 1,3-dimethyl-2-imidazolidinone, 62 mmol of diethylamine, and 1.88 g of sodium cyanoborohydride to a four-necked flask equipped with a reflux condenser, stir evenly, adjust the pH to 3 with a 10 wt % aqueous formic acid solution, stir and react at room temperature for 18 h, then heat to 84° C., continue to react for 3 h, cool to room temperature, extract twice with 194 g of chloroform, combine the extracts and perform vacuum distillation to obtain a viscous solid;

[0052] (2) The viscous solid was transferred to a four-necked flask with 292 g of isopropanol, 172 mmol of dodecyl bromide was added, and the mixture was heated to reflux for 38 h. During the reflux process, isopropanol was continuously added to maintain a substantially stable amount of the reaction solvent.

[0053] (3) 76% of the isopropanol was removed from the mixed solution under reduced pressure, and the remaining concentrated solution was distilled under reduced pressure on a rotary evaporator until there was no distillate at 72°C to obtain a viscous solid, which was recrystallized from ethyl acetate to obtain a light yellow solid, which was dried in an oven at 83°C for 4 h to obtain the product fungicide F.

[0054] Example 7: Evaluation of sterilization rate

[0055] In a series of narrow-necked bottles, 500 ml of water samples from a joint station of Shengli Oilfield containing SRB (sulfate-reducing bacteria), TGB (saprophytes), and FB (iron bacteria) were added, and different concentrations of AF and 1227 (dodecyl dimethyl benzyl ammonium chloride) were added, shaken, placed in a 50°C oven, and sampled after 1 hour. The remaining bacterial content was detected by the three-tube MPN method, and the sterilization rate was calculated. The SRB sterilization results are shown in Table 1, the TGB sterilization results are shown in Table 2, and the FB sterilization results are shown in Table 3.

[0056] Table 1 SRB sterilization results (sterilization rate, %)

[0057] Concentration, mg / L 5 10 15 20 30 A 86.7 95.6 100 100 100 B 85.6 96.7 100 100 100 C 90.2 97.9 100 100 100 D 90 99.5 100 100 100 E 90 100 100 100 100 F 93.3 100 100 100 100 1227 0 0 59.1 72.7 99

[0058] Table 2 TGB sterilization results (sterilization rate, %)

[0059]

[0060]

[0061] Table 3FB sterilization results (sterilization rate, %)

[0062] Concentration, mg / L 5 10 15 20 30 A 91.1 100 100 100 100 B 97.6 100 100 100 100 C 98.7 100 100 100 100 D 99.3 100 100 100 100 E 99.3 100 100 100 100 F 100 100 100 100 100 1227 0 33.3 81.8 99.3 100

[0063] From Table 1 we can see that:

[0064] (1) The bactericidal rates of fungicides A, B, C, D, E, and F of the present invention against SRB are all greater than 85% when used at a concentration of 5 mg / L, among which the bactericidal rate of fungicide F is the highest at 93.3%; the bactericidal rates against SRB are all greater than 95% when used at a concentration of 10 mg / L, among which the bactericidal rates of fungicides E and F are the highest at 100%; and the bactericidal rates against SRB are all 100% when used at a concentration of 15 mg / L. However, the bactericidal rates of fungicide 1227 are 0% when used at concentrations of 5 mg / L and 10 mg / L, and are 59.1%, 72.7%, and 99% when used at concentrations of 15 mg / L, 20 mg / L, and 30 mg / L, respectively. The bactericidal rate of fungicide 1227 against SRB is significantly lower than that of the present invention.

[0065] (2) The bactericides A, B, C, D, E, and F of the present invention have a bactericidal rate against TGB greater than 89% when used at a concentration of 5 mg / L, among which the bactericide F has a highest bactericidal rate of 99%; the bactericidal rate against TGB greater than 99% when used at a concentration of 10 mg / L, among which the bactericidal rates of bactericides C, D, E, and F are the highest at 100%; the bactericidal rate against TGB is 100% when used at a concentration of 15 mg / L. However, the bactericidal rate of bactericide 1227 is 0% when used at concentrations of 5 mg / L and 10 mg / L, and is 72.7%, 89.5%, and 99.3% when used at concentrations of 15 mg / L, 20 mg / L, and 30 mg / L, respectively. The bactericidal rate of bactericide 1227 against TGB is significantly lower than that of the present invention.

[0066] (3) The sterilization rates of fungicides A, B, C, D, E, and F of the present invention on FB are all greater than 91% when used at a concentration of 5 mg / L, among which the sterilization rate of fungicide F is the highest, which is 100%; and the sterilization rates on FB are all 100% when used at a concentration of 10 mg / L. However, the sterilization rate of fungicide 1227 is 0% when used at a concentration of 5 mg / L, and is 33.3%, 81.8%, 99.3%, and 100% when used at concentrations of 10 mg / L, 15 mg / L, 20 mg / L, and 30 mg / L, respectively. The sterilization rate of fungicide 1227 on FB is significantly lower than that of the present invention.

[0067] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. An oilfield produced water bactericide, characterized in that: The molecular structure of the bactericide is as follows:

2. The method for synthesizing the oilfield produced water bactericide according to claim 1, characterized in that: The preparation method is as follows: (1) Add water, 1,3-dimethyl-2-imidazolidinone, diethylamine, and sodium cyanoborohydride to a four-necked flask equipped with a reflux condenser, stir evenly, adjust the pH to 3-4 with a 10 wt % formic acid aqueous solution, stir and react at room temperature, then heat to 80-85° C., continue to react for 1-3 hours, cool to room temperature, extract twice with chloroform, combine the extracts and perform vacuum distillation to obtain a viscous solid; (2) transferring the viscous solid to a four-necked flask with isopropanol, adding dodecyl bromide, heating to reflux, continuously adding isopropanol during the reflux process to maintain a substantially stable amount of the reaction solvent, and reacting to obtain a mixed solution; (3) 70-80% of the isopropanol is removed from the mixed solution under reduced pressure, and the remaining concentrated solution is distilled under reduced pressure on a rotary evaporator until there is no distillate at 70-75° C. to obtain a viscous solid, which is recrystallized from ethyl acetate to obtain a light yellow solid, which is dried in an oven at 80-85° C. for 4-6 hours to obtain a product, i.e., a fungicide.

3. The method for synthesizing the oilfield produced water fungicide according to claim 2, characterized in that: Based on 1 mol part of 1,3-dimethyl-2-imidazolidinone, the usage amounts of diethylamine and dodecyl bromide are 0.9-1.5 mol parts and 2.5-4 mol parts respectively.

4. The method for synthesizing the oilfield produced water bactericide according to claim 3, characterized in that: Based on 1 mol part of 1,3-dimethyl-2-imidazolidinone, the usage amounts of diethylamine and dodecyl bromide are 1.1-1.4 mol parts and 3-4 mol parts respectively.

5. The method for synthesizing the oilfield produced water bactericide according to claim 2, characterized in that: The mass ratio of water to 1,3-dimethyl-2-imidazolidinone in step (1) is 20-30:

1.

6. The method for synthesizing the oilfield produced water bactericide according to claim 2, characterized in that: The mass ratio of sodium cyanoborohydride to 1,3-dimethyl-2-imidazolidinone in step (1) is 0.2-0.4:

1.

7. The method for synthesizing the oilfield produced water fungicide according to claim 2, characterized in that: The stirring reaction time at room temperature in step (1) is 12-24 hours.

8. The method for synthesizing the oilfield produced water fungicide according to claim 7, characterized in that: The stirring reaction time at room temperature is 16-20 hours.

9. The method for synthesizing the oilfield produced water bactericide according to claim 2, characterized in that: The mass ratio of chloroform to 1,3-dimethyl-2-imidazolidinone in step (1) is 30-40:

1.

10. The method for synthesizing the oilfield produced water fungicide according to claim 2, characterized in that: The heating reflux time in step (2) is 24-48h.

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