Acid-resistant and temperature-resistant organic corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention discloses an acid-resistant and temperature-resistant organic corrosion inhibitor and a preparation method and application thereof in the field of metal corrosion inhibition, and the acid-resistant and temperature-resistant organic corrosion inhibitor comprises the following raw materials: phytic acid, 2, 5-dimercapto-1, 3, 4-thiadiazole, propargyl alcohol, 5-carboxyl benzotriazole, hexadecyl trimethyl ammonium bromide, butylated hydroxytoluene, alkaloid and ethylene glycol. Wherein the alkaloid is selected from rhynchophylline, and the rhynchophylline is subjected to heterocyclic ring modification treatment, so that a pyridine group is introduced to an indole ring of the rhynchophylline. The phytic acid is selected as a main corrosion inhibition component and forms a protective film by chelating metal ions, meanwhile, the 2, 5-dimercapto-1, 3, 4-thiadiazole, the propargyl alcohol, the 5-carboxybenzotriazole and the alkaloid are used as auxiliary corrosion inhibitors, multi-mechanism synergistic promotion is achieved, the corrosion inhibition effect is remarkably enhanced, meanwhile, the dispersity is improved through hexadecyl trimethyl ammonium bromide, and the corrosion inhibition effect is improved. The dibutyl hydroxytoluene is used for improving the oxidation resistance, so that the corrosion inhibition effect of the whole corrosion inhibitor in high temperature and strong acid is very prominent.

Description

Technical Field

[0001] The invention relates to the technical field of metal corrosion inhibition, and in particular to an acid-resistant and temperature-resistant organic corrosion inhibitor, a preparation method and application thereof. Background Art

[0002] Corrosion inhibitors are organic and / or inorganic compounds that slow down or prevent metal corrosion through chemical or physical effects. They are widely used in industrial cooling water systems, oil and gas field exploitation, metal processing and pickling, anti-rust packaging and coating, etc. Their main mechanism of action is that the corrosion inhibitor molecules are adsorbed on the metal surface to form a dense protective film, which prevents the corrosive liquid from contacting the metal. For example, imidazoline corrosion inhibitors are adsorbed on the metal surface through polar groups, and the non-polar groups form a hydrophobic phase outward.

[0003] Common types of corrosion inhibitors include organic corrosion inhibitors and organic-inorganic composite corrosion inhibitors. Among them, composite corrosion inhibitors are currently the most widely used, and their corrosion inhibition effect is relatively stable. Organic corrosion inhibitors, such as some heterocyclic compounds, sulfur / nitrogen-containing organic matter, high molecular polymers, etc., have a relatively simple corrosion inhibition mechanism and lack of synergistic effects, resulting in an overall corrosion inhibition effect that is not as good as that of composite corrosion inhibitors. Especially in high temperature and strong acid environments, they are easy to decompose or desorb, resulting in a lack of corrosion inhibition performance. For example: Patent document with publication number CN116239585B discloses an acylhydrazone organic corrosion inhibitor, a preparation method and its application in epoxy coatings, which only achieves metal corrosion inhibition through chelation curing of ketoacylhydrazone groups; for another example: Patent document with publication number CN113402448B discloses a tripyridine primary amine organic corrosion inhibitor and its preparation method and application, which also only achieves metal corrosion inhibition through the three pyridine groups contained and Fe 2+ Ions form multidentate chelate ligands to achieve metal corrosion inhibition. These organic slow-release agents have a relatively simple corrosion inhibition mechanism and have poor corrosion inhibition effects in high temperature and strong acid environments. Summary of the invention

[0004] The purpose of the present invention is to provide an acid-resistant and temperature-resistant organic corrosion inhibitor, a preparation method and an application thereof, which solve the problem that the existing organic corrosion inhibitor has a poor corrosion inhibition effect in a high temperature and strong acid environment.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: An acid-resistant and temperature-resistant organic corrosion inhibitor, the raw materials of which include, by mass percentage: Phytic acid: 18-22%; 2,5-dimercapto-1,3,4-thiadiazole: 12-15%; Propynol: 6-8%; 5-Carboxybenzotriazole: 4-6%; Hexadecyltrimethylammonium bromide: 3-5%; Butylated hydroxytoluene: 2-3%; Alkaloids: 0.1-0.5%; Ethylene glycol: balance; The alkaloid is rhynchophylline, and the rhynchophylline is subjected to heterocyclic modification treatment to introduce a pyridine group on its indole ring.

[0006] The present invention also provides a method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor, the steps comprising: S1, taking rhynchophylline and subjecting it to heterocyclic modification treatment to introduce a pyridine group on its indole ring; S2, taking phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline treated in step S1, adding them into a reaction kettle, then adding ethylene glycol, heating to 60-70° C., stirring until completely dissolved, to obtain solution A; S3, cooling the solution A to below 50° C., then sequentially adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene, and continuously stirring for 20-30 minutes until the mixture is uniform, to obtain solution B; S4, circulating the solution B through a 100-150 MPa high-pressure homogenizer for more than two times, and then filtering with a microfiltration membrane, and taking the filtrate to obtain the organic corrosion inhibitor.

[0007] A further improvement is that in step S1, the specific operation of the heterocyclic modification treatment is: S1-1, dissolve rhynchophylline in dichloromethane, add acetic anhydride and 4-dimethylaminopyridine, stir at room temperature for 1.5-2.5h, take the reaction solution and quench it with saturated NaHCO3, extract it with CH2Cl2, dry and concentrate it to obtain the acetylated product; S1-2, dissolving the acetylated product in dimethylformamide, cooling to 0°C, adding N-bromosuccinimide, warming to room temperature, stirring and reacting for 4-5h, taking the reaction solution and quenching with water, extracting with ethyl acetate, drying and concentrating, and column chromatography in sequence to obtain a brominated product; S1-3, dissolving the bromide, pyridine-3-boric acid, Pd(PPh3)4 and K2CO3 in a toluene / water solution, reacting at 75-85°C for 10-12h under nitrogen protection, cooling and filtering the reaction solution, extracting with ethyl acetate, drying and concentrating, and column chromatography to obtain a coupling product; S1-4, dissolving the coupling product in methanol, adding NaOH, and stirring the mixture for 2-3 hours at room temperature. The reaction solution is neutralized, concentrated, and recrystallized to obtain heterocyclic-modified Rhynchophylline.

[0008] A further improvement is that in step S1-1, for every 1 mmol of rhynchophylline, the amount of dichloromethane used is 10 mL, the amount of acetic anhydride used is 1.5 mmol, and the amount of 4-dimethylaminopyridine used is 0.1 mmol.

[0009] A further improvement is that in step S1-2, The NaHCO3 quenching process is as follows: add saturated NaHCO3 to the reaction solution in an amount of 1-1.5 times the volume of the reaction solution, shake for 1-2 minutes, let stand to separate the layers, separate the aqueous phase, and retain the organic phase; The CH2Cl2 extraction process is as follows: adding dichloromethane to the aqueous phase in an amount of 0.3-0.5 times the volume of the reaction solution, repeating the extraction twice, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated using a rotary evaporator.

[0010] A further improvement is that in step S1-2, for every 1 mmol of the acetylated product, the amount of dimethylformamide used is 10 mL, and the amount of N-bromosuccinimide used is 1.2 mmol.

[0011] A further improvement is that in step S1-2, The water quenching process is as follows: add 3-5 times the volume of water to the reaction solution, shake for 1-2 minutes, let stand to separate the layers, separate the aqueous phase, and retain the organic phase; The ethyl acetate extraction process is as follows: adding ethyl acetate in an amount of 0.3-0.5 times the volume of the reaction solution to the aqueous phase, repeating the extraction twice, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated by a rotary evaporator; The column chromatography process is as follows: filling silica gel to a column height of 20 cm and balancing with petroleum ether, dissolving the concentrated product in dichloromethane and slowly adding it to the top of the column for gradient elution, wherein the elution ratio of petroleum ether / ethyl acetate is 10:1, 5:1, and 3:1, respectively, collecting and combining the eluents, and concentrating under reduced pressure to obtain a purified brominated product.

[0012] A further improvement is that in step S1-3, for every 1 mmol of the bromide, the amount of the pyridine-3-boric acid is 1.5 mmol, the amount of the Pd(PPh3)4 is 0.05 mmol, the amount of the K2CO3 is 2 mmol, the amount of the toluene / water solution is 5 mL, and the volume concentration of toluene is 80%.

[0013] A further improvement is that in step S1-3, The cooling filtration process is as follows: cooling the reaction solution to room temperature, then slowly pouring it into a saturated NaCl solution that accounts for 3-5 times the volume of the reaction solution to dilute it, shaking it for 1-2 minutes to obtain a dilution, then filtering the dilution with a Buchner funnel to obtain a filtrate, allowing the filtrate to stand for stratification, separating the aqueous phase, and retaining the organic phase; The ethyl acetate extraction process is as follows: adding ethyl acetate in an amount of 0.3-0.5 times the volume of the reaction solution to the aqueous phase, repeating the extraction three times, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated by a rotary evaporator; The column chromatography process is as follows: filling silica gel to a column height of 20-22 cm and balancing with petroleum ether, dissolving the concentrated product in dichloromethane and slowly adding it to the top of the column for gradient elution, the elution ratio of petroleum ether / ethyl acetate is 10:1 and 5:1 respectively, collecting and combining the eluents, and concentrating under reduced pressure to obtain a purified coupling product.

[0014] A further improvement is that in step S1-4, for every 1 mmol of the coupling product, the amount of methanol used is 5 mL, and the amount of NaOH used is 2 mmol.

[0015] A further improvement is that in step S1-4, The neutralization and concentration process is as follows: neutralizing with hydrochloric acid to a pH of 6, and then concentrating with a rotary evaporator; The recrystallization process is as follows: dissolving the concentrate in 55-60°C methanol, filtering the filtrate, cooling it to room temperature, and then placing it in a 4°C environment for 12-24 hours to allow crystals to precipitate, filtering and collecting the crystals, and then washing the crystals with 0-4°C methanol and drying them.

[0016] The present invention also provides an application of the acid-resistant and temperature-resistant organic corrosion inhibitor in metal corrosion inhibition.

[0017] The beneficial effects of the present invention are: (1) The present invention selects phytic acid as the main corrosion inhibitor component, which forms a protective film by chelating metal ions. At the same time, 2,5-dimercapto-1,3,4-thiadiazole, propargyl alcohol, 5-carboxybenzotriazole and alkaloids are used as auxiliary corrosion inhibitors. Multiple mechanisms are synergistically promoted to significantly enhance the corrosion inhibition effect. At the same time, hexadecyltrimethylammonium bromide is used to improve the dispersibility, and butylated hydroxytoluene is used to improve the antioxidant property, so that the overall corrosion inhibition effect of the corrosion inhibitor in high temperature and strong acid is very outstanding.

[0018] (2) The corrosion inhibition and promotion effect of ordinary rhynchophylline is not obvious, and is even inferior to other alkaloids. However, the present invention uses rhynchophylline that has been modified with a heterocyclic ring, and a pyridine group is introduced into the indole ring to form a conjugated biheterocyclic structure, which enhances the molecular planarity and improves the adsorption energy, thereby promoting the indole ring to form a coordination bond with the metal surface through π-electrons to form adsorption, making the chelate film of phytic acid denser, while improving the stability of the film layer and significantly improving the overall corrosion inhibition effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Scanning electron microscope images of Q235 steel after treatment with organic corrosion inhibitors in each experimental group. DETAILED DESCRIPTION

[0020] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] 1. Main raw materials: Phytic acid (inositol hexaphosphate): molecular formula C6H 18 O 24 P6, molecular weight 660.04, purchased from Guangzhou Fufei Chemical Technology Co., Ltd.; 2,5-dimercapto-1,3,4-thiadiazole: molecular formula C2H4N2S3, molecular weight 152.26, purchased from Shanghai Yuanye Biotechnology Co., Ltd.; Propynol: molecular formula C3H4O, molecular weight 56.07, purchased from Henan Haiyuan Fine Chemical Co., Ltd.; 5-Carboxybenzotriazole: molecular formula C7H5N3O2, molecular weight 163.13, purchased from Zhengzhou Huiju Chemical Co., Ltd.; Hexadecyltrimethylammonium bromide: Molecular formula C 19 H 42 BrN, molecular weight 364.446, purchased from Anhui Banghao Chemical Co., Ltd.; Butylated hydroxytoluene: molecular formula C 15 H 24O, molecular weight 220.36, purchased from Henan Hengao Biotechnology Co., Ltd.; Rhynchophylline: Molecular formula C 22 H 28 N2O4, molecular weight 384.46, purchased from Sichuan Hengcheng Zhiyuan Biotechnology Co., Ltd.; Ethylene glycol: molecular formula (CH2OH)2, molecular weight 62.068, purchased from Henan Yuxi Chemical Products Co., Ltd.

[0022] 2. Embodiment

[0023] Example 1 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage: phytic acid 18%; 2,5-dimercapto-1,3,4-thiadiazole 15%; propargyl alcohol 6%; 5-carboxybenzotriazole 4%; hexadecyltrimethylammonium bromide 3%; dibutylhydroxytoluene 2%; heterocyclic modified rhynchophylline 0.1%; and ethylene glycol 51.9%.

[0024] The preparation method of the organic corrosion inhibitor comprises the following steps: S1. Take rhynchophylline and perform heterocyclic modification on it to introduce a pyridine group on its indole ring.

[0025] The specific operations are: S1-1, take 1mmol of rhynchophylline and dissolve it in 10mL of dichloromethane, add 1.5mmol of acetic anhydride and 0.1mmol of 4-dimethylaminopyridine, stir at room temperature for 1.5h, take the reaction solution, add saturated NaHCO3 accounting for 1 times the volume of the reaction solution to the reaction solution, shake for 1min and let stand for stratification, separate the aqueous phase, and retain the organic phase; add dichloromethane accounting for 0.3 times the volume of the reaction solution to the aqueous phase, repeat the extraction 2 times, combine all organic phases, and then wash the organic phase with saturated NaCl solution; transfer the organic phase to a flask, add anhydrous Na2SO4 according to the dosage ratio of 10mL organic phase: 0.5g anhydrous Na2SO4, stir at room temperature for 15min, collect the filtrate by filtration and concentrate it with a rotary evaporator; S1-2, dissolve the 1mmol of acetylated product in 10mL of dimethylformamide, cool to 0°C, add 1.2mmol of N-bromosuccinimide, warm to room temperature, and stir to react for 4h, take the reaction solution, add 3 times the volume of water to the reaction solution, shake for 1min, let stand and separate the aqueous phase, retain the organic phase, add 0.3 times the volume of the reaction solution of ethyl acetate to the aqueous phase, repeat the extraction twice, combine all organic phases, and then wash the organic phase with saturated NaCl solution , the organic phase was transferred to a flask, anhydrous Na2SO4 was added in a ratio of 10mL organic phase: 0.5g anhydrous Na2SO4, stirred at room temperature for 15min, and the filtrate was collected by filtration and concentrated on a rotary evaporator, silica gel was filled to a column height of 20cm, and balanced with petroleum ether, the concentrated product was dissolved in dichloromethane and slowly added to the top of the column, and gradient elution was performed, and the elution ratio of petroleum ether / ethyl acetate was 10:1, 5:1, and 3:1, respectively, and the eluent was collected and combined, and concentrated under reduced pressure to obtain a purified brominated product; S1-3, 1mmol of the bromide, 1.5mmol of pyridine-3-boric acid, 0.05mmol of Pd(PPh3)4 and 2mmol of K2CO3 were dissolved in 5mL of 80% toluene / water solution, and the mixture was reacted at 75°C for 10h under nitrogen protection. The reaction solution was taken and cooled to room temperature, and then slowly poured into a saturated NaCl solution 3 times the volume of the reaction solution for dilution, and shaken for 1min to obtain a dilution solution, and then the dilution solution was filtered with a Buchner funnel to obtain a filtrate. The filtrate was allowed to stand for stratification, and the aqueous phase was separated, the organic phase was retained, and ethyl acetate 0.3 times the volume of the reaction solution was added to the aqueous phase, and the extraction was repeated 3 times, all organic phases were combined, and the organic phase was washed with a saturated NaCl solution. The organic phase was transferred to a flask, and anhydrous Na2SO4 was added in a ratio of 10 mL of organic phase: 0.5 g of anhydrous Na2SO4, and the mixture was stirred at room temperature for 15 min. The filtrate was collected by filtration and concentrated using a rotary evaporator. Silica gel was filled to a column height of 20 cm and balanced with petroleum ether. The concentrated product was dissolved in dichloromethane and slowly added to the top of the column for gradient elution. The elution ratio of petroleum ether / ethyl acetate was 10:1 and 5:1, respectively. The eluents were collected and combined, and concentrated under reduced pressure to obtain a purified coupling product. S1-4, dissolve 1 mmol of the coupling product in 5 mL of methanol, add 2 mmol of NaOH, and stir at room temperature for 2 h. Take the reaction solution, neutralize it with hydrochloric acid to pH 6, and then concentrate it with a rotary evaporator. Dissolve the concentrate in 55°C methanol, filter and cool the filtrate to room temperature, and then place it in a 4°C environment for 12 h to allow crystals to precipitate. Collect the crystals by filtration, wash the crystals with 0°C methanol, and dry them to obtain heterocyclic modified Rhynchophylline; S2, taking phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline treated in step S1, adding them into a reaction kettle, then adding ethylene glycol, heating to 60° C., stirring until completely dissolved, to obtain solution A; S3, cooling the solution A to 50° C., and then sequentially adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene, and continuously stirring for 20 min until the mixture is uniform, to obtain solution B; S4, circulating the solution B through a 100 MPa high-pressure homogenizer twice, and then filtering it with a microfiltration membrane, and taking the filtrate to obtain the organic corrosion inhibitor.

[0026] Example 2 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage: 20% phytic acid; 14% 2,5-dimercapto-1,3,4-thiadiazole; 7% propargyl alcohol; 5% 5-carboxybenzotriazole; 4% hexadecyltrimethylammonium bromide; 2.5% dibutylhydroxytoluene; 0.3% rhynchophylline modified with heterocyclic ring; and 47.2% ethylene glycol.

[0027] The preparation method of the organic corrosion inhibitor comprises the following steps: S1. Take rhynchophylline and perform heterocyclic modification on it to introduce a pyridine group on its indole ring.

[0028] The specific operations are: S1-1, take 1mmol of rhynchophylline and dissolve it in 10mL of dichloromethane, add 1.5mmol of acetic anhydride and 0.1mmol of 4-dimethylaminopyridine, stir at room temperature for 2h, take the reaction solution, add saturated NaHCO3 accounting for 1.2 times the volume of the reaction solution to the reaction solution, shake for 1.5min and let stand for stratification, separate the aqueous phase, and retain the organic phase; add dichloromethane accounting for 0.4 times the volume of the reaction solution to the aqueous phase, repeat the extraction 2 times, combine all organic phases, and then wash the organic phase with saturated NaCl solution; transfer the organic phase to a flask, add anhydrous Na2SO4 according to the dosage ratio of 10mL organic phase: 0.8g anhydrous Na2SO4, stir at room temperature for 25min, collect the filtrate by filtration and concentrate it with a rotary evaporator; S1-2, dissolve the 1mmol of acetylated product in 10mL of dimethylformamide, cool to 0°C, add 1.2mmol of N-bromosuccinimide, warm to room temperature, and stir to react for 4.5h, take the reaction solution, add water 4 times the volume of the reaction solution to the reaction solution, shake for 1.5min, let stand and separate the aqueous phase, retain the organic phase, add 0.4 times the volume of the reaction solution of ethyl acetate to the aqueous phase, repeat the extraction twice, combine all the organic phases, and then wash the organic phase with saturated NaCl solution. The organic phase was transferred to a flask, and anhydrous Na2SO4 was added in a ratio of 10 mL of organic phase: 0.8 g of anhydrous Na2SO4, and the mixture was stirred at room temperature for 25 min. The filtrate was collected by filtration and concentrated using a rotary evaporator. Silica gel was filled to a column height of 20 cm and balanced with petroleum ether. The concentrated product was dissolved in dichloromethane and slowly added to the top of the column for gradient elution. The elution ratios of petroleum ether / ethyl acetate were 10:1, 5:1, and 3:1, respectively. The eluents were collected and combined, and concentrated under reduced pressure to obtain a purified brominated product. S1-3, 1mmol of the bromide, 1.5mmol of pyridine-3-boric acid, 0.05mmol of Pd(PPh3)4 and 2mmol of K2CO3 were dissolved in 5mL of 80% toluene / water solution, and the mixture was reacted at 80°C for 11h under nitrogen protection. The reaction solution was taken and cooled to room temperature, and then slowly poured into a saturated NaCl solution 4 times the volume of the reaction solution to dilute it, and shaken for 1.5min to obtain a dilution. The dilution was then filtered with a Buchner funnel to obtain a filtrate. The filtrate was allowed to stand for stratification, and the aqueous phase was separated. The organic phase was retained, and 0.4 times the volume of the reaction solution of ethyl acetate was added to the aqueous phase. The extraction was repeated 3 times, all organic phases were combined, and the organic phase was washed with a saturated NaCl solution. , the organic phase was transferred to a flask, anhydrous Na2SO4 was added in a ratio of 10 mL of organic phase: 0.8 g of anhydrous Na2SO4, and the mixture was stirred at room temperature for 25 min. The filtrate was collected by filtration and concentrated using a rotary evaporator. Silica gel was filled to a column height of 20 cm and balanced with petroleum ether. The concentrated product was dissolved in dichloromethane and slowly added to the top of the column for gradient elution. The elution ratios of petroleum ether / ethyl acetate were 10:1 and 5:1, respectively. The eluents were collected and combined, and concentrated under reduced pressure to obtain a purified coupling product; S1-4, dissolve 1 mmol of the coupling product in 5 mL of methanol, add 2 mmol of NaOH, and stir at room temperature for 2.5 hours. Take the reaction solution, neutralize it with hydrochloric acid to pH 6, and then concentrate it with a rotary evaporator. Dissolve the concentrate in 58°C methanol, filter and cool the filtrate to room temperature, and then place it in a 4°C environment for 18 hours to allow crystals to precipitate. Collect the crystals by filtration, wash the crystals with 2°C methanol, and dry them to obtain heterocyclic modified Rhynchophylline; S2, taking phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline treated in step S1, adding them into a reaction kettle, then adding ethylene glycol, heating to 65° C., stirring until completely dissolved, to obtain solution A; S3, cooling the solution A to 48° C., and then sequentially adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene, and continuously stirring for 25 min until the mixture is uniform, to obtain solution B; S4, the solution B is circulated through a 120 MPa high-pressure homogenizer for three times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0029] Example 3 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage: phytic acid 22%; 2,5-dimercapto-1,3,4-thiadiazole 12%; propargyl alcohol 8%; 5-carboxybenzotriazole 6%; hexadecyltrimethylammonium bromide 5%; dibutylhydroxytoluene 3%; heterocyclic modified rhynchophylline 0.5%; and ethylene glycol 43.5%.

[0030] The preparation method of the organic corrosion inhibitor comprises the following steps: S1. Take rhynchophylline and perform heterocyclic modification on it to introduce a pyridine group on its indole ring.

[0031] The specific operations are: S1-1, take 1mmol of rhynchophylline and dissolve it in 10mL of dichloromethane, add 1.5mmol of acetic anhydride and 0.1mmol of 4-dimethylaminopyridine, stir at room temperature for 2.5h, take the reaction solution, add saturated NaHCO3 accounting for 1.5 times the volume of the reaction solution to the reaction solution, shake for 2min and let stand for stratification, separate the aqueous phase, and retain the organic phase; add dichloromethane accounting for 0.5 times the volume of the reaction solution to the aqueous phase, repeat the extraction 2 times, combine all organic phases, and then wash the organic phase with saturated NaCl solution; transfer the organic phase to a flask, add anhydrous Na2SO4 according to the dosage ratio of 10mL organic phase: 1g anhydrous Na2SO4, stir at room temperature for 30min, collect the filtrate by filtration and concentrate it with a rotary evaporator; S1-2, dissolve the 1mmol of acetylated product in 10mL of dimethylformamide, cool to 0°C, add 1.2mmol of N-bromosuccinimide, warm to room temperature, and stir to react for 5h, take the reaction solution, add 5 times the volume of water to the reaction solution, shake for 2min, let stand and separate the aqueous phase, retain the organic phase, add 0.5 times the volume of ethyl acetate to the aqueous phase, repeat the extraction twice, combine all the organic phases, and wash the organic phase with saturated NaCl solution. phase, the organic phase was transferred to a flask, anhydrous Na2SO4 was added in a ratio of 10mL organic phase: 1g anhydrous Na2SO4, and the mixture was stirred at room temperature for 30min. The filtrate was collected by filtration and concentrated using a rotary evaporator. Silica gel was filled to a column height of 20cm and balanced with petroleum ether. The concentrated product was dissolved in dichloromethane and slowly added to the top of the column for gradient elution. The elution ratio of petroleum ether / ethyl acetate was 10:1, 5:1, and 3:1, respectively. The eluents were collected and combined, and concentrated under reduced pressure to obtain a purified brominated product; S1-3, 1mmol of the bromide, 1.5mmol of pyridine-3-boric acid, 0.05mmol of Pd(PPh3)4 and 2mmol of K2CO3 were dissolved in 5mL of 80% toluene / water solution, and the mixture was reacted at 85°C for 12h under nitrogen protection. The reaction solution was taken, cooled to room temperature, and then slowly poured into a saturated NaCl solution 5 times the volume of the reaction solution to dilute it. The solution was shaken for 2min to obtain a dilution, and then the dilution was filtered with a Buchner funnel to obtain a filtrate. The filtrate was allowed to stand for stratification, and the aqueous phase was separated. The organic phase was retained, and ethyl acetate 0.5 times the volume of the reaction solution was added to the aqueous phase. The extraction was repeated 3 times, all organic phases were combined, and the organic phase was washed with a saturated NaCl solution. , the organic phase was transferred to a flask, anhydrous Na2SO4 was added in a ratio of 10 mL of organic phase: 1 g of anhydrous Na2SO4, and the mixture was stirred at room temperature for 30 min. The filtrate was collected by filtration and concentrated using a rotary evaporator. Silica gel was filled to a column height of 22 cm and balanced with petroleum ether. The concentrated product was dissolved in dichloromethane and slowly added to the top of the column for gradient elution. The elution ratios of petroleum ether / ethyl acetate were 10:1 and 5:1, respectively. The eluates were collected and combined, and concentrated under reduced pressure to obtain a purified coupling product; S1-4, dissolve 1 mmol of the coupling product in 5 mL of methanol, add 2 mmol of NaOH, and stir at room temperature for 3 h. Take the reaction solution, neutralize it with hydrochloric acid to pH 6, and then concentrate it with a rotary evaporator. Dissolve the concentrate in 60°C methanol, filter and cool the filtrate to room temperature, and then place it in a 4°C environment for 24 h to allow crystals to precipitate. Collect the crystals by filtration, wash the crystals with 4°C methanol, and dry them to obtain heterocyclic modified Rhynchophylline; S2, taking phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline treated in step S1, adding them into a reaction kettle, then adding ethylene glycol, heating to 70° C., stirring until completely dissolved, to obtain solution A; S3, cooling the solution A to 48° C., and then sequentially adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene, and continuously stirring for 30 min until the mixture is uniform, to obtain solution B; S4, the solution B is circulated through a 150 MPa high-pressure homogenizer for more than two times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0032] Comparative Example 1 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage, 22% phytic acid; 12% 2,5-dimercapto-1,3,4-thiadiazole; 8% propargyl alcohol; 6% 5-carboxybenzotriazole; 5% hexadecyltrimethylammonium bromide; 3% dibutylhydroxytoluene; 0.5% rhynchophylline; and 43.5% ethylene glycol.

[0033] The preparation method of the organic corrosion inhibitor comprises the following steps: S1. Take phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline (not treated with heterocyclic ring modification), add them into a reaction kettle, then add ethylene glycol, heat to 70°C, stir until completely dissolved, and obtain solution A; S2, cooling the solution A to 48° C., then adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene in sequence, and stirring for 30 minutes until the mixture is uniform, to obtain solution B; S3, the solution B is circulated through a 150 MPa high-pressure homogenizer for more than two times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0034] Comparative Example 2 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage: 22% phytic acid; 12% 2,5-dimercapto-1,3,4-thiadiazole; 8% propargyl alcohol; 6% 5-carboxybenzotriazole; 5% hexadecyltrimethylammonium bromide; 3% dibutylhydroxytoluene; 0.5% Schiff base (amino acid Schiff base is used here, purchased from Sichuan Hengcheng Zhiyuan Biotechnology Co., Ltd.); and 43.5% ethylene glycol.

[0035] The preparation method of the organic corrosion inhibitor comprises the following steps: S1, take phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and Schiff base, add them into a reaction kettle, then add ethylene glycol, heat to 70°C, stir until completely dissolved, and obtain solution A; S2, cooling the solution A to 48° C., then adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene in sequence, and stirring for 30 minutes until the mixture is uniform, to obtain solution B; S3, the solution B is circulated through a 150 MPa high-pressure homogenizer for more than two times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0036] Comparative Example 3 An acid-resistant and temperature-resistant organic corrosion inhibitor, wherein the raw materials include, by mass percentage: phytic acid 22%; 2,5-dimercapto-1,3,4-thiadiazole 12%; propynyl alcohol 8%; 5-carboxybenzotriazole 6%; hexadecyltrimethylammonium bromide 5%; dibutylhydroxytoluene 3%; matrine (molecular formula C 15 H 24 N 2O , molecular weight 248.37, purchased from Sichuan Hengcheng Zhiyuan Biotechnology Co., Ltd.) 0.5%; ethylene glycol 43.5%.

[0037] The preparation method of the organic corrosion inhibitor comprises the following steps: S1, take phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and matrine, add them into a reaction kettle, then add ethylene glycol, heat to 70°C, stir until completely dissolved, and obtain solution A; S2, cooling the solution A to 48° C., then adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene in sequence, and stirring for 30 minutes until the mixture is uniform, to obtain solution B; S3, the solution B is circulated through a 150 MPa high-pressure homogenizer for more than two times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0038] Comparative Example 4 An acid-resistant and temperature-resistant organic corrosion inhibitor, whose raw materials include, by mass percentage, 22.5% of phytic acid; 12% of 2,5-dimercapto-1,3,4-thiadiazole; 8% of propargyl alcohol; 6% of 5-carboxybenzotriazole; 5% of hexadecyltrimethylammonium bromide; 3% of dibutylhydroxytoluene; and 43.5% of ethylene glycol.

[0039] The preparation method of the organic corrosion inhibitor comprises the following steps: S1. Take phytic acid, 2,5-dimercapto-1,3,4-thiadiazole and 5-carboxybenzotriazole, add them into a reaction kettle, then add ethylene glycol, heat to 70°C, stir until completely dissolved, and obtain solution A; S2, cooling the solution A to 48° C., then adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene in sequence, and stirring for 30 minutes until the mixture is uniform, to obtain solution B; S3, the solution B is circulated through a 150 MPa high-pressure homogenizer for more than two times, and then filtered through a microfiltration membrane, and the filtrate is taken to obtain the organic corrosion inhibitor.

[0040] 3. Performance Test Test material: Q235 steel is selected, and its chemical composition is as shown in Table 1:

[0041] Table 1: Chemical composition of Q235 steel and its mass percentage (%) Strong acid corrosion medium: Take multiple 250mL portions of 0.1M H2SO4 solution, and then take the organic corrosion inhibitors prepared in the above Example 3 and Comparative Examples 1-4, and add each group of organic corrosion inhibitors to the H2SO4 solution respectively. The mass concentration of the organic corrosion inhibitor added is controlled at 0.5%. At the same time, a blank group (H2SO4 solution without adding organic corrosion inhibitor) is set to obtain each group of strong acid corrosion media.

[0042] Specific steps: First, Q235 steel was processed into specimens with a size of 30 mm × 20 mm × 10 mm, and then each surface of the specimen was polished to a bright finish using 180#, 400#, 800#, 1200#, and 2000# sandpapers in sequence. The specimens were then cleaned with distilled water, ultrasonically treated with anhydrous ethanol for 3 min, and wiped clean with absorbent paper. The specimens were then placed in a desiccator for 24 h and weighed on an analytical balance.

[0043] After weighing, the Q235 steel samples were placed in the above-mentioned strong acid corrosion media for 24 hours, and the temperature was controlled at 60°C in a constant temperature water bath during the corrosion treatment. After the corrosion treatment was completed, the corrosion products on the corrosion samples were removed in accordance with GB / T16545-1996, and ultrasonic cleaning was performed with distilled water and anhydrous ethanol, and wiped clean with absorbent paper. After each sample was placed in a desiccator for 24 hours, it was weighed again with an analytical balance.

[0044] The surface morphology of the corroded samples was analyzed using a TESCAN VEGA Ⅲ scanning electron microscope; then, the corrosion rate and corrosion inhibition efficiency were calculated: The calculation formula of corrosion rate is as follows:

[0045] Where v is the corrosion rate, is the mass before weightlessness, is the mass after weightlessness, is the surface area of ​​the sample, is the corrosion time of the sample.

[0046] The calculation formula of corrosion inhibition efficiency is as follows:

[0047] In the formula, is the corrosion rate of the blank sample, is the corrosion rate of the sample after adding organic corrosion inhibitor.

[0048] IV. Results Analysis (1) Surface morphology analysis results: Figure 1 The SEM images of each Q235 steel sample after corrosion treatment, wherein AF correspond to Example 3, blank group, comparative example 1, comparative example 2, comparative example 3, and comparative example 4, respectively. It can be seen that Example 3 and comparative examples 1-4 of the present invention have obvious corrosion inhibition effects compared with the blank group, among which the surface of Example 3 is still relatively flat, the degree of corrosion is the lightest, and the corrosion inhibition effect is the best. Comparative example 1 using ordinary rhynchophylline (without heterocyclic modification treatment) and comparative example 4 (without adding any alkaloids) both show obvious corrosion marks and poor corrosion inhibition effect. Comparative example 2 (replacing rhynchophylline with Schiff base) and comparative example 3 (replacing rhynchophylline with matrine) both show a certain degree of corrosion marks and the corrosion inhibition effect is general.

[0049] (2) Corrosion inhibition efficiency results: Table 2: Corrosion inhibition efficiency results of various embodiments and comparative examples

[0050] As can be seen from Table 2, the corrosion inhibition efficiency IE of the organic corrosion inhibitor prepared in Example 3 of the present invention can reach 91.03%, which is very excellent. In Comparative Example 1, ordinary rhynchophylline (without heterocyclic modification treatment) is used, and its corrosion inhibition efficiency IE is significantly reduced to 70.37%, which is a certain improvement compared with Comparative Example 4 (without any alkaloids added), but the improvement is very small; and the corrosion inhibition effect of Comparative Example 1 is inferior to that of Comparative Example 2 (replacing rhynchophylline with Schiff base) and Comparative Example 3 (replacing rhynchophylline with matrine), which shows that the process of heterocyclic modification treatment is very important, otherwise the synergistic corrosion inhibition of ordinary rhynchophylline is not as good as other alkaloids, and after heterocyclic modification treatment, the corrosion inhibition efficiency of rhynchophylline is significantly better than other alkaloids, which was not expected before the experiment.

[0051] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. An acid-resistant and temperature-resistant organic corrosion inhibitor, characterized in that: By mass percentage, its raw materials include: Phytic acid: 18-22%; 2,5-dimercapto-1,3,4-thiadiazole: 12-15%; Propynol: 6-8%; 5-Carboxybenzotriazole: 4-6%; Hexadecyltrimethylammonium bromide: 3-5%; Butylated hydroxytoluene: 2-3%; Alkaloids: 0.1-0.5%; Ethylene glycol: balance; The alkaloid is rhynchophylline, and the rhynchophylline is subjected to heterocyclic modification treatment to introduce a pyridine group on its indole ring.

2. A method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 1, characterized in that the steps include: S1, taking rhynchophylline and subjecting it to heterocyclic modification treatment to introduce a pyridine group on its indole ring; S2, taking phytic acid, 2,5-dimercapto-1,3,4-thiadiazole, 5-carboxybenzotriazole, and rhynchophylline treated in step S1, adding them into a reaction kettle, then adding ethylene glycol, heating to 60-70° C., stirring until completely dissolved, to obtain solution A; S3, cooling the solution A to below 50° C., then sequentially adding propargyl alcohol, hexadecyltrimethylammonium bromide, and butylated hydroxytoluene, and continuously stirring for 20-30 minutes until the mixture is uniform, to obtain solution B; S4, circulating the solution B through a 100-150 MPa high-pressure homogenizer for more than two times, and then filtering with a microfiltration membrane, and taking the filtrate to obtain the organic corrosion inhibitor.

3. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 2, characterized in that: In step S1, the specific operation of the heterocyclic modification treatment is: S1-1, dissolve rhynchophylline in dichloromethane, add acetic anhydride and 4-dimethylaminopyridine, stir at room temperature for 1.5-2.5h, take the reaction solution and quench it with saturated NaHCO3, extract it with CH2Cl2, dry and concentrate it to obtain the acetylated product; S1-2, dissolving the acetylated product in dimethylformamide, cooling to 0°C, adding N-bromosuccinimide, warming to room temperature, stirring and reacting for 4-5h, taking the reaction solution and quenching with water, extracting with ethyl acetate, drying and concentrating, and column chromatography in sequence to obtain a brominated product; S1-3, dissolving the bromide, pyridine-3-boric acid, Pd(PPh3)4 and K2CO3 in a toluene / water solution, reacting at 75-85°C for 10-12h under nitrogen protection, cooling and filtering the reaction solution, extracting with ethyl acetate, drying and concentrating, and column chromatography to obtain a coupling product; S1-4, dissolving the coupling product in methanol, adding NaOH, and stirring the mixture for 2-3 hours at room temperature. The reaction solution is neutralized, concentrated, and recrystallized to obtain heterocyclic-modified Rhynchophylline.

4. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-1, for every 1 mmol of rhynchophylline, the amount of dichloromethane used is 10 mL, the amount of acetic anhydride used is 1.5 mmol, and the amount of 4-dimethylaminopyridine used is 0.1 mmol.

5. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-2, The NaHCO3 quenching process is as follows: add saturated NaHCO3 to the reaction solution in an amount of 1-1.5 times the volume of the reaction solution, shake for 1-2 minutes, let stand to separate the layers, separate the aqueous phase, and retain the organic phase; The CH2Cl2 extraction process is as follows: adding dichloromethane to the aqueous phase in an amount of 0.3-0.5 times the volume of the reaction solution, repeating the extraction twice, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated using a rotary evaporator.

6. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-2, for every 1 mmol of the acetylated product, the amount of dimethylformamide used is 10 mL, and the amount of N-bromosuccinimide used is 1.2 mmol.

7. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-2, The water quenching process is as follows: add 3-5 times the volume of water to the reaction solution, shake for 1-2 minutes, let stand to separate the layers, separate the aqueous phase, and retain the organic phase; The ethyl acetate extraction process is as follows: adding ethyl acetate in an amount of 0.3-0.5 times the volume of the reaction solution to the aqueous phase, repeating the extraction twice, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated by a rotary evaporator; The column chromatography process is as follows: filling silica gel to a column height of 20 cm and balancing with petroleum ether, dissolving the concentrated product in dichloromethane and slowly adding it to the top of the column for gradient elution, wherein the elution ratio of petroleum ether / ethyl acetate is 10:1, 5:1, and 3:1, respectively, collecting and combining the eluents, and concentrating under reduced pressure to obtain a purified brominated product.

8. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-3, for every 1 mmol of the bromide, the amount of the pyridine-3-boric acid is 1.5 mmol, the amount of the Pd(PPh3)4 is 0.05 mmol, the amount of the K2CO3 is 2 mmol, the amount of the toluene / water solution is 5 mL, and the volume concentration of toluene is 80%.

9. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-3, The cooling filtration process is as follows: cooling the reaction solution to room temperature, then slowly pouring it into a saturated NaCl solution that accounts for 3-5 times the volume of the reaction solution to dilute it, shaking it for 1-2 minutes to obtain a dilution, then filtering the dilution with a Buchner funnel to obtain a filtrate, allowing the filtrate to stand for stratification, separating the aqueous phase, and retaining the organic phase; The ethyl acetate extraction process is as follows: adding ethyl acetate in an amount of 0.3-0.5 times the volume of the reaction solution to the aqueous phase, repeating the extraction three times, combining all organic phases, and then washing the organic phase with a saturated NaCl solution; The drying and concentration process is as follows: the organic phase is transferred to a flask, anhydrous Na2SO4 is added in a ratio of 10 mL of organic phase: 0.5-1 g of anhydrous Na2SO4, stirred at room temperature for 15-30 min, and then the filtrate is collected by filtration and concentrated by a rotary evaporator; The column chromatography process is as follows: filling silica gel to a column height of 20-22 cm and balancing with petroleum ether, dissolving the concentrated product in dichloromethane and slowly adding it to the top of the column for gradient elution, the elution ratio of petroleum ether / ethyl acetate is 10:1 and 5:1 respectively, collecting and combining the eluents, and concentrating under reduced pressure to obtain a purified coupling product.

10. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-4, for every 1 mmol of the coupling product, the amount of methanol used was 5 mL, and the amount of NaOH used was 2 mmol.

11. The method for preparing the acid-resistant and temperature-resistant organic corrosion inhibitor according to claim 3, characterized in that: In step S1-4, The neutralization and concentration process is as follows: neutralizing with hydrochloric acid to a pH of 6, and then concentrating with a rotary evaporator; The recrystallization process is as follows: dissolving the concentrate in 55-60°C methanol, filtering the filtrate, cooling it to room temperature, and then placing it in a 4°C environment for 12-24 hours to allow crystals to precipitate, filtering and collecting the crystals, and then washing the crystals with 0-4°C methanol and drying them.

12. Use of the acid-resistant and temperature-resistant organic corrosion inhibitor as claimed in claim 1 in inhibiting metal corrosion.

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