Preparation method for and use of rosin thiourea imidazole quaternary ammonium salt

Abstract

A preparation method and an application of a rosin thiourea imidazole quaternary ammonium salt, belonging to the technical field of microbioligically influenced corrosion and protection. In order to find a green and environmentally friendly quaternary ammonium salt having both bactericidal and anti-corrosion effects, the present invention utilizes the natural chiral environment (hydrophobic) of rosin, and, by means of connecting a fat chain containing a thiourea unit with an imidazole quaternary ammonium salt unit (hydrophilic), further prepares the green and environmentally friendly rosin thiourea imidazole quaternary ammonium salt. Through electrochemical analysis, corrosion morphology characterization, corrosion weight loss analysis, and live and dead cell characterization, a rosin thiourea imidazole quaternary ammonium salt is obtained, which can reduce metal corrosion current density, reduce biofilm thickness, and achieve the effect of inhibiting microbiologically influenced corrosion. The rosin thiourea imidazole quaternary ammonium salt obtained by the present invention has a broad antibacterial spectrum, and has a significant inhibitory effect on both Gram-negative bacteria and Gram-positive bacteria at a mass concentration of 0.05 g / L. Moreover, the preparation method is simple, economical and efficient, cheap and easy to obtain, and suitable for large-scale production.

Description

Preparation method and application of rosin-based thiourea imidazole quaternary ammonium salt Technical Field

[0001] The invention belongs to the field of metal microbial corrosion and protection, and particularly relates to a preparation method of a rosin-based thiourea imidazole quaternary ammonium salt and an application thereof as a microbial corrosion inhibitor. Background Art

[0002] Microbiologically influenced corrosion (MIC) refers to the phenomenon in which the metabolic activities of microorganisms directly or indirectly lead to the corrosion and degradation of metal materials. It is reported that the economic losses caused by microbial corrosion in my country have exceeded 400 billion yuan each year, accounting for 20% of all corrosion losses. Sulfate-reducing bacteria are one of the main microorganisms causing microbial corrosion. Problems such as oil pipeline leakage and offshore platform equipment failure caused by sulfate-reducing bacteria corrosion have become difficult problems that need to be solved urgently in China's industrial field. The first step in microbial corrosion is the formation of biofilm on the surface of metal materials. Therefore, inhibiting the formation of biofilm is an effective means of microbial corrosion prevention and control.

[0003] In recent years, environmentally friendly corrosion inhibitors have been paid more and more attention because of their good biodegradability and biofriendliness. Quaternary ammonium salts, as an ionic salt, mainly contain N heterocyclic compounds to carry out the inhibitor active molecule that quaternization reaction obtains, and have excellent high temperature resistance when used as microbial corrosion inhibitors, without special irritating smell and low toxicity. But the quaternary ammonium salt anticorrosive materials currently used also have some shortcomings and harms, such as narrow antimicrobial spectrum, as low-efficiency anticorrosive materials, without killing effect on microorganisms such as fungi, tuberculosis bacillus, hydrophilic viruses, and are susceptible to environmental influences. The quaternary ammonium salt anticorrosive inhibitors currently on the market are susceptible to factors such as pH, water quality, and temperature. Partial quaternary ammonium salt agents (such as quaternary ammonium benzalkonium bromide) can react with the metal ions in high hardness water to reduce the effective concentration of quaternary ammonium salt, thereby cannot reach corresponding effect. Simultaneously, certain damage is also caused to environment and organism, so researchers are devoted to finding the environmentally friendly quaternary ammonium salt that synthesizes sterilization and anticorrosive action concurrently.

[0004] Rosin is a major forest chemical source and is widely used in industry. Previous studies have shown that rosin quaternary ammonium salts have metal corrosion inhibition effects, but there are problems such as few rosin quaternary ammonium salt structure types and single functionality. The present invention is guided by the diversified synthesis of rosin quaternary ammonium salts and finds its anti-microbial corrosion performance. Utilizing the natural chiral environment (hydrophobic) of rosin, a fatty chain containing a thiourea unit is connected to an imidazole quaternary ammonium salt unit (hydrophilic), and plays a role in inhibiting corrosion through physical adsorption and chemical adsorption.

[0005] Summary of the Invention

[0006] In order to overcome the shortcomings of bacterial resistance, environmental damage and biological damage caused by the use of existing quaternary ammonium salts as anti-corrosion materials, a method for preparing a rosin-based thiourea imidazole quaternary ammonium salt as a microbial anti-corrosion material and its application are provided. The rosin-based thiourea imidazole quaternary ammonium salt prepared by the present invention not only has excellent corrosion resistance and anti-biofilm formation properties, but also has excellent broad-spectrum antibacterial effect. In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] The preparation method of the rosin-based thiourea imidazole quaternary ammonium salt of the present invention comprises the following steps:

[0008] Step 1: N,N'-dicyclohexylcarbodiimide, carbon disulfide and dehydroabietinamine (Compound A) dissolved in ether solution are mixed and stirred for reaction. After thiourea is separated, solid isothiocyanate (Compound B) is obtained by elution and separation.

[0009] Step 2: Compound B and 3-(1H-imidazole)-1-propylamine (Compound C) were added to dichloromethane and stirred to react to obtain a crude product D without purification.

[0010] Step 3: Add the crude product D and benzyl bromide to a toluene solution, stir and react, and elute and separate to obtain a white solid product, rosin-based thiourea imidazole quaternary ammonium salt.

[0011] In the step 1, the stirring reaction temperature is 0°C and the reaction time is 6 to 18 hours.

[0012] In the step 1, the molar ratio of N,N'-dicyclohexylcarbodiimide to dehydroabietinamine is 1:1 to 1:4.

[0013] In the step 1, the separation method is silica gel column chromatography, and the eluent is 25% ethyl acetate: n-hexane in a mass ratio of 1:1 to 1:5.

[0014] In the steps 2 and 3, the stirring time is 6 to 18 hours in a nitrogen atmosphere.

[0015] In the step 3, the separation method is flash chromatography.

[0016] The application of the rosin-based thiourea imidazole quaternary ammonium salt as a microbial anti-corrosion material comprises the following steps:

[0017] Step 1: Mix rosin-based thiourea imidazole quaternary ammonium salt with an ethanol solution to prepare an ethanol solution of rosin-based thiourea imidazole quaternary ammonium salt, which is used as a corrosion inhibitor.

[0018] Step 2: Add a corrosion inhibitor of rosin-based thiourea imidazole quaternary ammonium salt ethanol solution to a Gram-negative sulfate-reducing bacterium solution of Desulfovibrio spp. under anaerobic conditions and a Gram-positive Bacillus licheniformis solution under aerobic conditions containing metal materials for cultivation to complete the corrosion inhibition experiment.

[0019] In step 1, the ethanol solution has a mass concentration of 10-20%, and the rosin-based thiourea imidazole quaternary ammonium salt ethanol solution has a mass concentration of 1.0-2.0 g / L. In step 2, the metal material is selected from carbon steel and stainless steel, more preferably X80 carbon steel and 316L stainless steel.

[0020] In the step 2, the Gram-negative bacteria is the sulfate-reducing bacterium Desulfovibrio, and the Gram-positive bacteria is Bacillus licheniformis.

[0021] The rosin-based thiourea imidazole quaternary ammonium salt prepared by the present invention is used to culture the same metal material simultaneously with a corrosion inhibitor of a rosin-based thiourea imidazole quaternary ammonium salt ethanol solution added thereto as an experimental group, and a blank control group without any microbial corrosion inhibitor added thereto as a blank control group. The test shows that the corrosion efficiency of the microbial corrosion material in the experimental group with the inhibitor of the rosin-based thiourea imidazole quaternary ammonium salt ethanol solution added is reduced by more than 90%.

[0022] The invention has the following beneficial effects: the preparation method is simple, economical and efficient. The preparation process of rosin-based thiourea imidazole quaternary ammonium salt is carried out under mild reaction conditions at 0°C, with few and simple synthesis steps and readily available raw materials, which is suitable for large-scale production.

[0023] Green and environmentally friendly. Rosin base is a natural compound extracted from plants, which has little harm to humans and the environment. The prepared rosin-based thiourea imidazole quaternary ammonium salt can be used as an environmentally friendly microbial inhibitor.

[0024] Reduces metal corrosion current density and inhibits microbial corrosion. The rosin-based thiourea imidazole quaternary ammonium salt prepared by the present invention is more easily adsorbed on the metal surface than water to form a physical protective layer, reducing the metal corrosion current density, thereby inhibiting microbial corrosion.

[0025] Reduce film thickness and inhibit microbial corrosion. The rosin-based thiourea imidazole quaternary ammonium salt prepared by the present invention can eliminate bacteria and reduce the thickness of biofilm formed on the metal surface, thereby inhibiting microbial corrosion.

[0026] Strong antibacterial effect. The rosin-based thiourea imidazole quaternary ammonium salt prepared by the present invention has a strong ability to inhibit corrosion at a mass concentration of 0.05g / L, and has a significant inhibitory effect on both Gram-negative and Gram-positive bacteria, as well as the effect of inhibiting biofilm formation. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the examples. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents. Experimental methods without specific conditions are generally based on conventional conditions. The quantitative experiments in the examples were repeated three or more times to avoid experimental errors.

[0028] The preparation process of the rosin-based thiourea imidazole quaternary ammonium salt ethanol solution of the microbial corrosion inhibitor used in the following examples is as follows: the prepared rosin-based thiourea imidazole quaternary ammonium salt is mixed with a 10-20% ethanol solution, filtered, and prepared into a rosin-based thiourea imidazole quaternary ammonium salt ethanol solution with a mass concentration of 1.0-2.0 g / L.

[0029] The corrosion materials used in this embodiment are X80 carbon steel and 316L stainless steel. The mass percentages of the X80 carbon steel components are as follows: 0.07% C, 1.82% Mn, 0.19% Si, 0.045% S, 0.045% P, 0.17% Ni, 0.01% Mo, 0.026% Cr, with Fe as the balance; the mass percentages of the 316L stainless steel components are as follows: 0.019% C, 1.18% Mn, 0.43% Si, 10.5% Ni, 16.78% Cr, 2.09% Mo, 0.032% P, 0.0006% S, with Fe as the balance. The dimensions of the metal materials used are 10 mm × 10 mm × 5 mm.

[0030] Example 1

[0031] At 0°C, N,N'-dicyclohexylcarbodiimide (20 mmol, 4.13 g), carbon disulfide (4.0 mL), and dehydroabietamine (20 mmol, 5.70 g, compound A) dissolved in ether were mixed. After 3 hours of reaction, the mixture was slowly heated to room temperature and stirred for another 12 hours. The precipitated thiourea was separated by filtration, and the solvent was removed under low pressure. After silica gel column chromatography, elution was performed with 25% ethyl acetate: n-hexane in a ratio of 1:3 to obtain a white solid isothiocyanate (compound B) with a yield of 92% (6.0 g); Compound B (3.0 g) and 3-(1H-imidazole)-1-propylamine (10 mmol, 1.25 g, compound C) were added to dichloromethane (80 mL) and stirred for 12 hours under a nitrogen atmosphere for reaction. After reflux, the solvent was removed under low pressure to obtain crude product D without purification.

[0032] The crude product D and bromobenzyl (1.0 equivalent) were added to a toluene (10 mL) solution and stirred for 12 h in a nitrogen atmosphere for reaction. After reflux, the solvent was removed under reduced pressure and eluted by flash column chromatography to obtain a white solid product, rosin-based thiourea imidazole quaternary ammonium salt.

[0033] Example 2

[0034] At 0°C, N,N'-dicyclohexylcarbodiimide (20 mmol, 4.13 g), carbon disulfide (4.0 mL), and dehydroabietamine (40 mmol, 11.40 g, compound A) dissolved in ether solution were mixed, and after 3 hours of reaction, the mixture was slowly heated to room temperature and stirred for another 6 hours. After filtering to separate the precipitated thiourea, the solvent was removed under low pressure. After silica gel column chromatography, elution was performed with 25% ethyl acetate: n-hexane in a ratio of 1:1 to obtain a white solid isothiocyanate (compound B) with a yield of 90% (5.87 g); Compound B (3.0 g) and 3-(1H-imidazole)-1-propylamine (10 mmol, 1.25 g, compound C) were added to dichloromethane (80 mL) and stirred for 12 hours under a nitrogen atmosphere for reaction. After reflux, the solvent was removed under low pressure to obtain a crude product D without purification.

[0035] The crude product D and bromobenzyl (1.0 equivalent) were added to a toluene (10 mL) solution and stirred for 6 h in a nitrogen atmosphere for reaction. After reflux, the solvent was removed under reduced pressure and eluted by flash column chromatography to obtain a white solid product, rosin-based thiourea imidazole quaternary ammonium salt.

[0036] Example 3

[0037] At 0°C, N,N'-dicyclohexylcarbodiimide (20 mmol, 4.13 g), carbon disulfide (4.0 mL), and dehydroabietamine (80 mmol, 22.84 g, compound A) dissolved in ether solution were mixed, and after 3 hours of reaction, the mixture was slowly heated to room temperature and stirred for another 18 hours. After filtering to separate the precipitated thiourea, the solvent was removed at low pressure. After silica gel column chromatography, elution was performed with 25% ethyl acetate: n-hexane at a ratio of 1:5 to obtain a white solid isothiocyanate (compound B) with a yield of 89% (5.80 g); Compound B (3.0 g) and 3-(1H-imidazole)-1-propylamine (10 mmol, 1.25 g, compound C) were added to dichloromethane (80 mL) and stirred for 18 hours under a nitrogen atmosphere for reaction. After reflux, the solvent was removed at low pressure to obtain a crude product D without purification.

[0038] The crude product D and bromobenzyl (1.0 equivalent) were added to a toluene (10 mL) solution and stirred for 18 h in a nitrogen atmosphere for reaction. After reflux, the solvent was removed under reduced pressure and eluted by flash column chromatography to obtain a white solid product, rosin-based thiourea imidazole quaternary ammonium salt.

[0039] Example 4

[0040] The culture medium used in this example is ATCC1249 culture medium, which contains 1.0 g / L yeast extract, 5.0 g / L sodium citrate, 3.5 g / L sodium lactate, 1.0 g / L calcium sulfate, 1.0 g / L ammonium chloride, 2.0 g / L magnesium sulfate, 1.0 g / L ammonium ferrous sulfate hexahydrate, and 0.5 g / L potassium phosphate.

[0041] 1) Electrochemical analysis of the anticorrosion properties of rosin-based thiourea imidazole quaternary ammonium salt:

[0042] X80 steel was used as a sample and mounted as an electrode. Under anaerobic conditions, rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was added to ATCC1249 culture medium to 0.05g / L as the experimental group, and ATCC1249 culture medium without rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was used as the blank control group. The same X80 carbon steel working electrode was immersed in both the experimental group and the blank control group for 7 days. Using a three-electrode system, the open circuit potential, linear polarization resistance, electrochemical impedance spectroscopy and other data of the X80 carbon steel in the blank control group and the experimental group were tested every day using an electrochemical workstation. After the 7-day immersion experiment, the corrosion current density (i corr Compared with the blank control group, the corrosion current density of X80 carbon steel in the experimental group increased from 7.6μA / cm 2 (i corr ) dropped to 1.6μA / cm 2 (i′ corr ), and its corrosion inhibition rate was 79% (calculated using Formula 1). After electrochemical testing, it was found that the linear polarization resistance of the experimental group also increased with the addition of rosin-based thiourea imidazole quaternary ammonium salt, indicating that rosin-based thiourea imidazole quaternary ammonium salt has the effect of inhibiting microbial corrosion under sterile conditions.

[0043] Formula 1:

[0044] i corr : Corrosion current density of X80 carbon steel working electrode without adding rosin-based thiourea imidazolium quaternary ammonium salt.

[0045] i′ corr : Corrosion current density of X80 carbon steel working electrode with addition of rosin-based thiourea imidazolium quaternary ammonium salt.

[0046] Example 5

[0047] The culture medium used in this example is ATCC1249 medium, which contains 1.0 g / L yeast extract, 5.0 g / L sodium citrate, 3.5 g / L sodium lactate, 1.0 g / L calcium sulfate, 1.0 g / L ammonium chloride, 2.0 g / L magnesium sulfate, 1.0 g / L ferrous ammonium sulfate hexahydrate, and 0.5 g / L potassium phosphate. A 1% solution of the sulfate-reducing bacterium Desulfovibrio was added to the prepared ATCC1249 medium and set aside.

[0048] The confocal microscope used in this embodiment is Zeiss LSM 900.

[0049] 1) Electrochemical analysis of the anticorrosion properties of rosin-based thiourea imidazolium quaternary ammonium salt.

[0050] X80 steel was used as a sample and mounted as an electrode. Under anaerobic conditions, 0.05 g / L of rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was added to 1% ATCC1249 culture medium of sulfate-reducing bacteria Desulfovibrio spp. as the experimental group, and 1% ATCC1249 culture medium of sulfate-reducing bacteria Desulfovibrio spp. without rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was used as the blank control group. The same X80 carbon steel working electrode was placed in the experimental group and the blank control group and cultured for 7 days. Using a three-electrode system, the corrosion performance, open circuit potential, linear polarization resistance, electrochemical impedance and other data of the X80 carbon steel in the blank control group and the experimental group were tested every day using an electrochemical workstation. After the 7-day immersion experiment, the corrosion current density (i corr Compared with the blank control group, the corrosion current density of X80 carbon steel in the experimental group increased from 91.7μA / cm 2 (i corr ) dropped to 5.5μA / cm 2 (i′ corr ), and its corrosion inhibition rate was 94% (calculated using Formula 1). Electrochemical tests showed that the linear polarization resistance of the experimental group also increased with the addition of rosin-based thiourea imidazolium quaternary ammonium salt.

[0051] 2) Corrosion weight loss analysis of the anti-corrosion properties of rosin-based thiourea imidazolium quaternary ammonium salt.

[0052] An X80 carbon steel sample was placed in a 1% sulfate-reducing bacterium solution containing 0.05 g / L rosin-based thiourea imidazole quaternary ammonium salt in ethanol as an experimental group. A similar X80 carbon steel sample was placed in a 1% sulfate-reducing bacterium solution containing no rosin-based thiourea imidazole quaternary ammonium salt in ethanol as a blank control group. Both the experimental and blank control groups were cultured for 7 days. After removing corrosion products and biofilm, the sample masses (W1) and (W2) before and after the immersion experiment were measured using a balance. Calculation results show that the corrosion inhibition rate of the X80 carbon steel sample immersed in ATCC1249 culture medium containing 1% sulfate-reducing bacterium solution after adding 0.05 g / L rosin-based thiourea imidazole quaternary ammonium salt in ethanol was 95% (calculated using Formula 2).

[0053] Formula 2:

[0054] W1: Mass of X80 carbon steel sample before immersion experiment.

[0055] W2: Mass of X80 carbon steel sample after immersion test.

[0056] 3) Characterization of corrosion morphology of the anti-corrosion properties of rosin-based thiourea imidazolium quaternary ammonium salt.

[0057] An X80 carbon steel sample was placed in a 1% sulfate-reducing bacterium culture containing 0.05 g / L rosin-based thiourea imidazole quaternary ammonium salt in ethanol as an experimental group. A blank control group was placed in a 1% sulfate-reducing bacterium culture without the rosin-based thiourea imidazole quaternary ammonium salt in ethanol. Both the experimental and blank control groups were incubated for 7 days. After removing corrosion products and biofilm, the corrosion morphology was characterized using a scanning electron microscope. The X80 carbon steel samples in the experimental group had a smooth surface with no obvious corrosion pits, while the blank control group had corrosion pits up to 20 microns deep.

[0058] 4) Analysis of corrosion products of rosin-based thiourea imidazole quaternary ammonium salt anti-corrosion properties:

[0059] An X80 carbon steel sample was placed in a 1% sulfate-reducing bacterium culture containing 0.05 g / L rosin-based thiourea imidazolate quaternary ammonium salt in ethanol as an experimental group. A blank control group was placed in a 1% sulfate-reducing bacterium culture containing no rosin-based thiourea imidazolate quaternary ammonium salt in ethanol as a control group. Both the experimental and blank control groups were incubated for 7 days. X-ray photoelectron spectroscopy was used to analyze the corrosion products formed on the surfaces of the X80 carbon steel samples in both the experimental and blank groups. FeS was the primary corrosion product in both conditions. The addition of rosin-based thiourea imidazolate quaternary ammonium salt reduced the formation of corrosion products but did not alter their nature.

[0060] Example 6

[0061] The culture medium used in this example is LB (Lurica-Bertani) medium, which contains 5.0 g / L yeast extract, 10 g / L tryptone, and 10 g / L sodium chloride.

[0062] 1) Electrochemical analysis of the anticorrosion properties of rosin-based thiourea imidazole quaternary ammonium salt:

[0063] 316L stainless steel was used as a sample and mounted as an electrode. Under aerobic conditions, 0.05 g / L of rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was added to LB culture medium as the experimental group, and LB culture medium without rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was used as the blank control group. The same 316L stainless steel working electrode was immersed in both the experimental group and the blank control group for 7 days. Using a three-electrode system, the open circuit potential, linear polarization resistance, electrochemical impedance and other data of the 316L stainless steel in the experimental group and the blank control group were tested every day using an electrochemical workstation. After the 7-day immersion experiment, the corrosion current density (i corr ). Compared with the blank control group, the corrosion current density of 316L stainless steel in the experimental group increased from 185nA / cm 2 (i corr ) dropped to 16.3nA / cm 2 (i′ corr ), with a corrosion inhibition rate of 91% (calculated using Formula 1). Electrochemical testing revealed that the linear polarization resistance of the experimental group also increased with the addition of rosin-based thiourea imidazolate quaternary ammonium salt. This indicates that rosin-based thiourea imidazolate quaternary ammonium salt has the ability to inhibit microbial corrosion under sterile conditions.

[0064] Example 7

[0065] The LB medium composition is: 5.0 g / L yeast extract, 10 g / L tryptone, and 10 g / L sodium chloride. 1% Bacillus licheniformis culture solution is added to the prepared LB medium and set aside.

[0066] The confocal microscope used in this embodiment is Zeiss LSM 900.

[0067] 1) Electrochemical analysis of the anticorrosion properties of rosin-based thiourea imidazole quaternary ammonium salt:

[0068] 316L stainless steel was used as a sample and mounted as an electrode. Under aerobic conditions, 0.05 g / L rosin-based thiourea imidazole quaternary ammonium salt ethanol solution was added to an LB culture medium containing 1% Bacillus licheniformis culture liquid as the experimental group, and a 316L stainless steel working electrode of the same species as the experimental group was placed in an LB culture medium containing 1% Bacillus licheniformis culture liquid but not containing rosin-based thiourea imidazole quaternary ammonium salt ethanol solution as the blank control group. Both the experimental group and the control group were cultured for 7 days. Using a three-electrode system, an electrochemical workstation was used to test the open circuit potential, linear polarization resistance, and electrochemical impedance of the 316L stainless steel in the experimental group and the blank control group. After 7 days of electrochemical testing, the polarization resistance value of the experimental group was higher than that of the blank control group. After 7 days of culture, the 316L stainless steel working electrode was subjected to a potentiodynamic polarization test, and the corrosion current density (i corr Compared with the blank control group, the corrosion current density of 316L stainless steel in the experimental group increased from 55.4nA / cm 2 (i corr ) dropped to 3.3nA / cm 2 (i′ corr ), and its corrosion inhibition rate was 94% (calculated using Formula 1). This shows that rosin-based thiourea imidazolium quaternary ammonium salt has an inhibitory effect on microbial corrosion.

[0069] 2) Characterization of live and dead cells of the antiseptic properties of rosin-based thiourea imidazolium quaternary ammonium salt:

[0070] A 316L stainless steel sample was placed in a 1% Bacillus licheniformis culture containing a 0.05 g / L ethanolic solution of rosin-based thiourea imidazole quaternary ammonium salt as the experimental group. A blank control group was placed in a 1% Bacillus licheniformis culture without the ethanolic solution of rosin-based thiourea imidazole quaternary ammonium salt as the experimental group. Both the experimental and blank controls were cultured for 7 days, and the biofilms on the 316L stainless steel surfaces were characterized using confocal microscopy. The results showed that a large number of dead cells appeared on the 316L stainless steel in the experimental group, while no dead cells appeared on the 316L stainless steel in the blank control group.

Claims

1. A method for preparing rosin-based thiourea imidazole quaternary ammonium salt, characterized in that: The following steps are involved: Step 1: N,N'-dicyclohexylcarbodiimide, carbon disulfide and dehydroabietinamine dissolved in ether solution are mixed, stirred for reaction, and solid isothiocyanate compound B is separated; Step 2: Add compound B and 3-(1H-imidazole)-1-propylamine to dichloromethane, stir, and reflux to obtain a crude product D; Step 3: reacting the crude product D with benzyl bromide, and eluting and separating after the reaction to obtain the product rosin-based thiourea imidazole quaternary ammonium salt; 2. The method for preparing the rosin-based thiourea imidazole quaternary ammonium salt according to claim 1, characterized in that: In the step 1, the stirring reaction temperature is 0°C and the reaction time is 6 to 18 hours.

3. The method for preparing the rosin-based thiourea imidazole quaternary ammonium salt according to claim 1, characterized in that: In the step 1, the molar ratio of N,N'-dicyclohexylcarbodiimide:dehydroabietinamine is 1:1 to 1:

4.

4. The method for preparing the rosin-based thiourea imidazole quaternary ammonium salt according to claim 1, characterized in that: In the step 1, the separation method is silica gel column chromatography, and the eluent is 25% ethyl acetate:n-hexane, with a mass ratio of 1:1 to 1:

5.

5. The method for preparing the rosin-based thiourea imidazole quaternary ammonium salt according to claim 1, characterized in that: In the steps 2 and 3, the stirring reaction time is 6 to 18 hours in a nitrogen atmosphere.

6. The method for preparing the rosin-based thiourea imidazole quaternary ammonium salt according to claim 1, characterized in that: In the step 3, the separation method is flash chromatography.

7. Rosin-based thiourea imidazole quaternary ammonium salt, characterized in that: Prepared by the preparation method of rosin-based thiourea imidazole quaternary ammonium salt according to any one of claims 1 to 6, the molecular formula is C 21 H 57 SN4Br.

8. Use of the rosin-based thiourea imidazole quaternary ammonium salt as a microbial corrosion inhibitor according to claim 7, characterized in that: The application method comprises the following steps: Step 1: Mix rosin-based thiourea imidazole quaternary ammonium salt with an ethanol solution to prepare a rosin-based thiourea imidazole quaternary ammonium salt ethanol solution as a corrosion inhibitor for standby use; Step 2: Add rosin-based thiourea imidazole quaternary ammonium salt corrosion inhibitor to the Gram-negative bacteria solution and Gram-positive bacteria solution containing metal materials for cultivation to achieve the purpose of microbial corrosion inhibition.

9. Use of the rosin-based thiourea imidazolate quaternary ammonium salt as a microbial corrosion inhibitor according to claim 8, characterized in that: In the step 1, the mass concentration of the ethanol solution is 10-20%.

10. Use of the rosin-based thiourea imidazolate quaternary ammonium salt as a microbial corrosion inhibitor according to claim 8, characterized in that: In the step 1, the mass concentration of the rosin-based thiourea imidazole quaternary ammonium salt ethanol solution is 1.0-2.0 g / L.

Images