Multifunctional corrosion inhibitor based on 1, 2-disubstituted-4, 5-dihydroimidazole organophosphorus carboxylic acid as well as preparation method and application of multifunctional corrosion inhibitor

Abstract

The invention relates to a multifunctional corrosion inhibitor based on 1, 2-disubstituted-4, 5-dihydroimidazole organophosphorus carboxylic acid as well as a preparation method and application thereof, the multifunctional corrosion inhibitor has a structure as shown in a formula I, in the formula I, R1 represents at least one of hydrogen, deuterium and alkyl; and R2 and R3 each independently represent at least one of hydrogen, deuterium, halogen, a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, a cyano group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, and a substituted or unsubstituted aryl group. The multifunctional corrosion inhibitor disclosed by the invention has the functions of corrosion inhibition, scale inhibition and sterilization at the same time, and can avoid the compatibility problem and antagonism caused by addition of various chemical agents when being used in the field of carbon dioxide oil displacement or gas displacement.

Description

Technical Field

[0001] This invention belongs to the field of oilfield technology and relates to a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, its preparation method and application. Background Technology

[0002] Greenhouse gas emission reduction is imperative, and carbon capture, utilization, and storage (CCUS) technology can effectively reduce CO2 emissions. This technology captures CO2 from carbon sources and then transports it to storage sites via pipelines or other means for utilization. Currently, it is mainly used for oil displacement or gas displacement. Numerous studies both domestically and internationally have shown that CO2 flooding has a more significant technological advantage than water flooding in developing low-permeability reserves and improving the recovery rate of old water-bearing oilfields. For example, according to the *China Energy News*, China has approximately 13 billion tons of crude oil geological reserves suitable for CO2 flooding. This method can increase the recovery rate by 15%, increase recoverable reserves by 1.92 billion tons, and store approximately 4.7 billion to 5.5 billion tons of carbon dioxide. Furthermore, research from the China University of Petroleum (Beijing) indicates that CO2 flooding technology has received widespread attention since the 1960s, involving multiple complex mechanisms such as dissolution, expansion, viscosity reduction, diffusion, and mass transfer.

[0003] However, during the process of using carbon dioxide to remove oil or gas, the system faces problems such as corrosion, scaling, and microbial growth, requiring the addition of chemical agents such as corrosion inhibitors, scale inhibitors, and bactericides to control these issues. In practical applications, various agents are added separately, making the process cumbersome. Furthermore, agents can interact with each other, and in some cases, poor compatibility can lead to antagonistic effects. This not only wastes resources but can also cause the injection and production system to fail and pipelines to be corroded and damaged.

[0004] Invention application CN102369949A discloses a scale inhibitor, corrosion inhibitor, and bactericide, which is composed of a mixture of bis(tributyltin oxide), 5-5-dichloro-2,2-dihydroxyxylmethane, methane dithiocyanate, ethanol, and water. The formula is reasonable and the production cost is low, but the antagonistic effect between the agents has not been solved.

[0005] Invention application CN113528106A discloses a corrosion inhibitor for suppressing carbon dioxide corrosion at high temperatures. The inhibitor comprises, by mass percentage: 15-80% polyoxyethylene alkylolamide, 1-30% organic alkynol, 0.1-5% potassium iodide, 1-30% ethyleneamine, 0.1-5% antimony trioxide, and 5-60% solvent. It exhibits excellent corrosion inhibition against carbon dioxide corrosion in oilfield systems at high temperatures of 250-350℃, with inhibition rates exceeding 80%. However, the long-term antagonistic effect of the various agents remains unresolved.

[0006] Therefore, existing technologies all obtain multifunctional corrosion inhibitors through compounding. Although they have both corrosion inhibition and scale inhibition properties, the effect is not good, and the antagonistic effect caused by multiple agents over a long period of time has not been solved. Summary of the Invention

[0007] In view of this, the main objective of the present invention is to provide a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid. This multifunctional corrosion inhibitor has the functions of corrosion inhibition, scale inhibition and bactericidal action. It can be used in the field of carbon dioxide flooding or gas displacement to solve the compatibility problems and antagonistic effects caused by adding a variety of chemical agents in the process of carbon dioxide flooding.

[0008] The present invention also provides a method for preparing a multifunctional corrosion inhibitor, which can prepare the above-mentioned multifunctional corrosion inhibitor, and the process is simple and low in cost.

[0009] The present invention also provides a functional composition, which, since it includes the above-mentioned multifunctional corrosion inhibitor, simultaneously possesses the functions of corrosion inhibition, scale inhibition, and bactericidal action.

[0010] The present invention also provides an application of the above-mentioned functional composition in the field of carbon dioxide flooding. Since the above-mentioned multifunctional corrosion inhibitor according to the present invention has the functions of corrosion inhibition, scale inhibition and bactericidal action, the above-mentioned multifunctional corrosion inhibitor, as a single compound, can achieve the functions of corrosion inhibition, scale inhibition and bactericidal action that are only possible with conventional compound compositions in the art, thereby simplifying the preparation process of the multifunctional corrosion inhibitor for the field of carbon dioxide flooding.

[0011] To achieve the above objectives, the present invention adopts the following technical solution.

[0012] In a first aspect, the present invention provides a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, the multifunctional corrosion inhibitor having the structure shown in Formula I:

[0013]

[0014] Among them, R 1 R represents at least one of hydrogen, deuterium, and alkyl groups; 2 and R 3 Each of the following groups independently represents at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl.

[0015] The multifunctional corrosion inhibitor described above, wherein R 1 It is at least one of alkyl groups having 1 to 20 carbon atoms.

[0016] As described above, the multifunctional corrosion inhibitor, R2 and R 3 In this context, the halogen is at least one of F, Cl, and Br.

[0017] As described above, the multifunctional corrosion inhibitor, R 2 and R 3 In this context, the alkoxy group is at least one of alkoxy groups having 1 to 10 carbon atoms.

[0018] As described above, the multifunctional corrosion inhibitor, R 2 and R 3 In this context, the alkyl group is at least one of a straight-chain or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.

[0019] As described above, the multifunctional corrosion inhibitor, R 2 and R 3 In this context, the aryl group is at least one of aryl groups having 6 to 30 carbon atoms.

[0020] The multifunctional corrosion inhibitor described above, wherein R 2 and R 3 It is at least one of substituted alkyl, substituted alkoxy, and substituted aryl, wherein the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy.

[0021] The multifunctional corrosion inhibitor described above, wherein R 2 and R 3 When each is represented as a substituted alkyl group, the substituent includes at least one of carbonyl, carboxyl, and ester groups.

[0022] The multifunctional corrosion inhibitor described above, wherein R 2 and R 3 When each is represented as a substituted cycloalkyl group, the substituent includes at least one of deuterium, halogen, and hydroxyl.

[0023] The multifunctional corrosion inhibitor described above, wherein R 2 and R 3 When each is represented as a substituted aryl group, the substituent includes at least one of deuterium, halogen, carbonyl, carboxyl, and trifluoromethyl.

[0024] As described above, the multifunctional corrosion inhibitor, R 1 R 2 and R 3 They can be the same or different.

[0025] The multifunctional corrosion inhibitor described above has at least one of the structures shown in formulas I-1 to I-26:

[0026]

[0027]

[0028] Secondly, the present invention provides a method for preparing the multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid as described above, comprising the following steps:

[0029] Step 1) Make organic carboxylic acid R 1 COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100–150 °C, followed by a dehydration cyclization reaction at 180–200 °C to obtain an intermediate; wherein the intermediate has the structure shown in Formula A;

[0030]

[0031] Step 2) Organophosphorus carboxylic acids (including R) 2 and R 3 The compound is reacted with a condensing agent (e.g., N,N'-carbonyldiimidazole (CDI)) in a second organic solvent, and then the intermediate obtained in step 1) is added and refluxed to obtain the multifunctional corrosion inhibitor.

[0032] In the above method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, in step 1), the organic carboxylic acid R... 1 The molar ratio of COOH to N-(2-aminoethyl)-ethane-1,2-diamine is (2.0~2.2):1.

[0033] In the above method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, in step 1), the organic carboxylic acid R... 1 COOH,R 1 It is at least one of hydrogen, deuterium, and alkyl groups.

[0034] In the above-described method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, in step 2), the condensation reagent includes at least one of N,N'-carbonyldiimidazole (CDI), dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI).

[0035] In this invention, the role of the condensing agent is to promote the condensation reaction of dehydration molecules between organophosphorus carboxylic acids and intermediates.

[0036] In the above method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, in step 2), the condensing agent is N,N'-carbonyldiimidazole (CDI), whose structural formula is shown below:

[0037]

[0038] In the above method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphoric acid, in step 2), the molar ratio between the organophosphoric acid, the condensation reagent, and the intermediate is 1:(1-1.6):1.

[0039] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, in step 2), the organophosphorus carboxylic acid has the structure shown in formula B:

[0040]

[0041] Among them, R 2 and R 3 Each of the following groups independently represents at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl.

[0042] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, R 2 and R 3 In this context, the alkoxy group is at least one of alkoxy groups having 1 to 10 carbon atoms.

[0043] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, R 2 and R 3 In this context, the alkyl group is at least one of a straight-chain or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.

[0044] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, R 2 and R 3 In this context, the aryl group is at least one of aryl groups having 6 to 30 carbon atoms.

[0045] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, the R... 2 and R 3It is at least one of substituted alkyl, substituted alkoxy, and substituted aryl, wherein the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy.

[0046] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, in step 1), all the first organic solvents include at least one of p-xylene, m-xylene, mesitylene, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0047] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphoric acid, in step 2), the second organic solvent includes at least one of DMF and DMSO.

[0048] In the above-mentioned method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, in step 1), the organic carboxylic acid R1COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100-150°C. After all the reactants are consumed, a dehydration cyclization reaction is carried out at 180-200°C to obtain an intermediate.

[0049] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, step 1) further includes: after carrying out a dehydration cyclization reaction at 180-200°C, the obtained dehydration cyclization product is subjected to column chromatography to obtain the intermediate.

[0050] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphoric acid, in step 2), the organophosphoric acid reacts with the condensation reagent in a second organic solvent at 20–30 °C.

[0051] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acids, the temperature of the reflux reaction in step 2) is 155-180°C.

[0052] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphoric acid, in step 2), the organophosphoric acid reacts with the condensation reagent in a second organic solvent until the system stops releasing gas, and then the intermediate obtained in step 1) is added for reflux reaction to obtain the multifunctional corrosion inhibitor.

[0053] In the above method for preparing corrosion inhibitors based on 1,2-disubstituted-4,5-dihydroimidazole organophosphoric acid, step 2) further includes: after the reflux reaction is completed, the reflux product is subjected to column chromatography to obtain the multifunctional corrosion inhibitor.

[0054] In this invention, taking 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) as an organophosphorus carboxylic acid to prepare a multifunctional corrosion inhibitor compound I-1 as an example, the chemical reaction principle of the preparation method of the multifunctional corrosion inhibitor is explained as follows:

[0055]

[0056] Thirdly, the present invention provides a functional composition comprising the above-mentioned multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, or the functional composition comprising a multifunctional corrosion inhibitor prepared by the above-mentioned method for preparing the multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid.

[0057] In this invention, the functional composition includes the multifunctional corrosion inhibitor described herein. The functional composition also possesses corrosion inhibition, scale inhibition, and bactericidal functions without the addition of other additives.

[0058] Fourthly, the present invention provides an application of the above-mentioned functional composition in the field of carbon dioxide displacement of oil or gas.

[0059] In this invention, the functional composition is diluted with water to obtain a functional composition solution, which can be directly used in the field of carbon dioxide oil displacement or gas displacement without the need to add other compounds to form a compound for application.

[0060] For example, the functional composition is diluted with water to obtain a functional composition solution with a mass content of 40%.

[0061] The multifunctional corrosion inhibitor provided by this invention is based on 1,2-disubstituted-4,5-dihydroimidazole, with acyl and phosphoryl groups introduced into the molecular structure, and the substituent R... 1 R 2 and R 3 Therefore, the multifunctional corrosion inhibitor provided by this invention has the functions of corrosion inhibition, scale inhibition and bactericidal action, which can avoid the compatibility problems and antagonistic effects caused by the addition of multiple chemical agents.

[0062] In this invention, the above-mentioned technical features can be freely combined to form new technical solutions, provided they do not conflict with each other.

[0063] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0064] (1) The multifunctional corrosion inhibitor of the present invention is based on 1,2-disubstituted-4,5-dihydroimidazole, and introduces acyl and phosphoryl groups into the molecular structure. The presence of imidazole and phosphoryl groups is beneficial to the corrosion inhibition performance of the corrosion inhibitor.

[0065] (2) The multifunctional corrosion inhibitor according to the present invention contains polar groups. Since polar groups can adsorb metal ions, the presence of corrosion inhibitors is beneficial to the fact that calcium and magnesium ions in the medium are not easily adsorbed and nucleated on the hydrophobic surface, so it is not easy to form a dense scale layer, thereby playing a scale inhibition role.

[0066] (3) The multifunctional corrosion inhibitor according to the present invention also contains non-polar groups. Since the non-polar groups can cover the metal surface, thereby inhibiting the migration of the metal, the presence of non-polar groups is beneficial for the corrosion inhibitor to exert its corrosion inhibition effect.

[0067] (4) The multifunctional corrosion inhibitor according to the present invention can contain both polar and non-polar groups. By adjusting the ratio of the two, it is beneficial for the corrosion inhibitor to perform both corrosion inhibition and scale inhibition functions at the same time.

[0068] (5) The multifunctional corrosion inhibitor according to the present invention has a phospholipid bilayer-like configuration, which is beneficial for resisting the adsorption and formation of biofilm by sulfate-reducing bacteria on the metal surface, thereby inhibiting microbial corrosion. Thus, it plays a bactericidal role. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0070] In a first aspect, some embodiments of the present invention provide a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, said multifunctional corrosion inhibitor having the structure shown in Formula I:

[0071]

[0072] Among them, R 1 R represents at least one of hydrogen, deuterium, and alkyl groups; 2 and R 3 Each of the following groups independently represents at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl.

[0073] The multifunctional corrosion inhibitor provided by this invention has the structure shown in Formula I above, that is, based on 1,2-disubstituted-4,5-dihydroimidazole as the basic structure, with acyl and phosphoryl groups introduced on this basis, and R... 1 R 2 and R 3 The substituents are used to define R. 1 R 2 and R 3 The substituents can be the same or different. The multifunctional corrosion inhibitor provided by this invention simultaneously possesses corrosion inhibition, scale inhibition, and bactericidal functions, avoiding compatibility issues and antagonistic effects caused by the addition of multiple chemical agents. This may be because:

[0074] (1) When the multifunctional corrosion inhibitor is adsorbed on the metal surface, the HOMO energy level is mainly distributed on the imidazole ring and the LUMO energy level is mainly distributed on the phosphoryl group segment, which improves the corrosion inhibition performance. In addition, different active groups are introduced into the multifunctional corrosion inhibitor molecule to form a relatively dense protective film on the metal surface, which further enhances its corrosion inhibition performance. Since the multifunctional corrosion inhibitor is an organic compound with a large shielding effect, the shielding effect refers to the fact that the multifunctional corrosion inhibitor molecule has both polar and non-polar groups. The migration of metal is inhibited by the adsorption of polar groups on the metal surface and the covering of non-polar groups on the metal surface, thereby achieving the corrosion inhibition effect.

[0075] (2) The shielding effect of multifunctional corrosion inhibitors is generally measured by the coverage area on the metal surface. When the adsorption capacity of multifunctional corrosion inhibitors is roughly the same, the larger the coverage area, the better the corrosion inhibition effect. When the adsorption area is high enough, calcium and magnesium ions in the medium are not easily adsorbed and nucleated on the hydrophobic surface, so it is not easy to form a dense scale layer. In the flowing medium, the loose precipitates are easily washed away by the fluid. Therefore, the multifunctional corrosion inhibitor also has the function of scale inhibition.

[0076] (3) When microbial corrosion occurs, sulfate-reducing bacteria in the environment adsorb onto the surface of the metal to form a biofilm. The metabolic activities of the bacteria in the biofilm directly or indirectly participate in the corrosion process, causing microbial corrosion. The structural feature of the bacterial cell membrane is that it has a certain degree of fluidity. The structure of the cell membrane is that the basic framework is composed of an intermediate phospholipid bilayer, and protein molecules are embedded, penetrated, or covered in the phospholipid bilayer or on the surface at different depths. Most of the phospholipid molecules and protein molecules that make up the membrane are mobile, and the movement of substances through the cell membrane is based on the fluidity of the membrane. The multifunctional corrosion inhibitor provided by this invention has a similar phospholipid bilayer configuration, which can change the fluidity of the cell membrane, thereby causing the cell membrane to rupture and the contents of the bacteria to flow out. Therefore, it can resist the adsorption of sulfate-reducing bacteria on the metal surface to form a biofilm and inhibit microbial corrosion.

[0077] In some embodiments of the present invention, the R 1 It is at least one of alkyl groups having 1 to 20 carbon atoms. The alkyl group can be a straight-chain or branched alkyl group having 1 to 20 carbon atoms, and more particularly, a straight-chain alkyl group having 10 to 20 carbon atoms.

[0078] In some embodiments of the present invention, R 2 and R 3 In this context, the halogen is at least one of F, Cl, and Br, and may further be Cl.

[0079] In some embodiments of the present invention, R 2 and R 3 In this context, the alkoxy group is at least one of alkoxy groups having 1 to 10 carbon atoms. The alkoxy group can be a straight-chain or branched alkoxy group having 1 to 10 carbon atoms, and may further be at least one of methoxy, ethoxy, and tert-butoxy groups.

[0080] In some embodiments of the present invention, R 2 and R 3 In this context, the alkyl group is at least one of a straight-chain or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.

[0081] The alkyl group can be a straight-chain or branched alkyl group having 1 to 10 carbon atoms, and can further be at least one of methyl, ethyl, propyl and tert-butyl. The alkyl group can also be a cycloalkyl group having 3 to 30 atoms, for example, a monocyclic, polycyclic or spirocyclic alkyl group, and can further be at least one of cyclopropyl or cyclohexyl.

[0082] In some embodiments of the present invention, R 2 and R 3 In this context, the aryl group is at least one of aryl groups having 6 to 30 carbon atoms. The aryl group can be a single aromatic ring or multiple aromatic rings, and may further be at least one of phenyl or naphthyl groups.

[0083] In some embodiments of the present invention, the R 2 and R 3 Each of the substituents is at least one of substituted alkyl, substituted alkoxy, and substituted aryl, and the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy.

[0084] In one implementation, R 2 and R 3Each is a straight-chain or branched substituted alkyl group having 1 to 10 carbon atoms, and the substituent is at least one selected from deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl and alkoxy, and may further be at least one selected from carbonyl, carboxyl or ester.

[0085] In another implementation, R 2 and R 3 Each of the substituents is at least one of substituted cycloalkyl groups having 3 to 30 carbon atoms, and the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl and alkoxy, and may further be at least one of deuterium, halogen or hydroxyl.

[0086] In another embodiment, R 2 and R 3 Each of the substituents is at least one of the substituted alkoxy groups, and the substituent is at least one of the following: deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy. It may further be at least one of aryl, trifluoromethyl, or alkoxy.

[0087] In yet another implementation, R 2 and R 3 Each of the substituents is at least one of the substituted aryl groups, and the substituent is at least one of the following: deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy. It may further be at least one of the following: deuterium, halogen, carbonyl, carboxyl, or trifluoromethyl.

[0088] In some embodiments of the present invention, the multifunctional corrosion inhibitor has at least one of the structures shown in formulas I-1 to I-26:

[0089]

[0090]

[0091] Secondly, some embodiments of the present invention provide a method for preparing a multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid as described above, comprising the following steps:

[0092] Step 1) Make organic carboxylic acid R 1 COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100–150 °C, followed by a dehydration cyclization reaction at 180–200 °C to obtain an intermediate; wherein the intermediate has the structure shown in Formula A;

[0093]

[0094] Step 2) Organophosphorus carboxylic acids (including R) 2 and R 3 The compound is reacted with a condensing agent (e.g., N,N'-carbonyldiimidazole (CDI)) in a second organic solvent, and then the intermediate obtained in step 1) is added and refluxed to obtain the multifunctional corrosion inhibitor.

[0095] In some embodiments of the present invention, in step 1), the organic carboxylic acid R 1 The molar ratio of COOH to N-(2-aminoethyl)-ethane-1,2-diamine is (2.0 to 2.2):1 (e.g., 2.0:1 or 2.1:1).

[0096] In some embodiments of the present invention, in step 1), the organic carboxylic acid R 1 COOH,R 1 It is at least one of hydrogen, deuterium, and alkyl groups.

[0097] In some embodiments of the present invention, in step 1), all the first organic solvents include at least one of p-xylene, m-xylene, mesitylene, DMF and DMSO; in step 2), the second organic solvent includes at least one of DMF and DMSO.

[0098] In some embodiments of the present invention, in step 1), the organic carboxylic acid R1COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100–150°C (e.g., 110°C, 120°C, 130°C, or 140°C). After all the reactants are consumed, a dehydration cyclization reaction is carried out at 180–200°C (e.g., 185°C, 190°C, or 195°C) to obtain an intermediate.

[0099] In some embodiments of the present invention, step 1) further includes: after carrying out a dehydration cyclization reaction at 180-200°C, the obtained dehydration cyclization product is subjected to column chromatography to obtain the intermediate.

[0100] In some embodiments of the present invention, in step 2), the organophosphorus carboxylic acid has the structure shown in formula B:

[0101]

[0102] Among them, R 2 and R 3 Each of the following groups independently represents at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl.

[0103] In some embodiments of the present invention, R 2 and R 3 In this context, the alkoxy group is at least one of alkoxy groups having 1 to 10 carbon atoms.

[0104] In some embodiments of the present invention, R 2 and R 3 In this context, the alkyl group is at least one of a straight-chain or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.

[0105] In some embodiments of the present invention, R 2 and R 3 In this context, the aryl group is at least one of aryl groups having 6 to 30 carbon atoms.

[0106] In some embodiments of the present invention, the R 2 and R 3 It is at least one of substituted alkyl, substituted alkoxy, and substituted aryl, wherein the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy.

[0107] In some embodiments of the present invention, in step 2), the condensation reagent includes at least one of N,N'-carbonyldiimidazole (CDI), dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIC), and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI).

[0108] In some embodiments of the present invention, in step 2), the condensing agent is N,N'-carbonyldiimidazole (CDI), whose structural formula is shown below:

[0109]

[0110] In the above-mentioned preparation method of the multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, in step 2), the molar ratio between the organophosphorus carboxylic acid, the condensing reagent and the intermediate is 1:(1~1.6):1 (e.g., 1:1:1, 1:1.1:1, 1:1.2:1, 1:1.3:1, 1:1.4:1, 1:1.5:1 or 1:1.6:1).

[0111] In some embodiments of the present invention, in step 2), the temperature of the reflux reaction is 155–180°C (e.g., 160°C, 165°C, 170°C, or 175°C).

[0112] In some embodiments of the present invention, the organophosphoric acid carboxylic acid and the condensation reagent are reacted in a second organic solvent at 20–30°C (e.g., 25°C).

[0113] In some embodiments of the present invention, in step 2), the organophosphorus carboxylic acid reacts with the condensation reagent in a second organic solvent until the system stops releasing gas, and then the intermediate obtained in step 1) is added to carry out a reflux reaction to obtain the multifunctional corrosion inhibitor.

[0114] In some embodiments of the present invention, step 2) further includes: after the reflux reaction is completed, the reflux product is subjected to column chromatography to obtain the multifunctional corrosion inhibitor.

[0115] Specifically, in step 1), the substituent R is included. 1 Organic carboxylic acids R 1 COOH and N-(2-aminoethyl)-ethane-1,2-diamine are added to a reaction flask at a specific molar ratio, for example, 2:1. A certain amount of solvent, such as p-xylene, is also added to the flask. A water separator is connected to the mouth of the flask. The reaction system is heated to 100–150°C and reacted for a certain time, for example, 3 hours, until all reactants are completely consumed, indicating that the carboxylic acid and amine have dehydrated to form an amide. Then, the reaction temperature is increased to 180–200°C and reacted for a certain time, for example, 15 hours, during which a cyclization reaction occurs between the reactants, yielding an intermediate with the formula shown in B. After the reaction at 180–200°C, the reaction solution is cooled, and the product is separated by column chromatography. The reaction solution is packed into a column, and an eluent is prepared with a suitable solvent. The reaction solution is eluted to obtain a solution containing the intermediate. The solution is collected, and the solvent is removed by vacuum distillation to obtain the intermediate. This invention does not limit the composition and ratio of the eluent, as long as it can elute the intermediate from the stationary phase.

[0116] In step 2), R will be included. 2 and R 3 The compound, an organophosphorus carboxylic acid, such as 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA), di-tert-butyl phosphate, or bis(p-methylphenyl)phosphine oxide, is added to a reaction flask, and an appropriate amount of solvent, such as N,N-dimethylformamide (DMF), is added to dissolve it. Then, an appropriate amount of condensing agent, such as N,N'-carbonyldiimidazole (CDI) dissolved in DMF, is added dropwise to the reaction flask. The condensing agent acts as an activating acid. The reaction is carried out at 20–30 °C until the system stops releasing gas. Here, the released gas is carbon dioxide. The intermediate with the above formula A is added and refluxed, for example, refluxed at 160 °C for 10 h. The resulting reaction mixture is then subjected to column chromatography to obtain the multifunctional corrosion inhibitor.

[0117] The preparation method of this invention is low in cost and simple in process. The multifunctional corrosion inhibitor prepared has the functions of corrosion inhibition, scale inhibition and bactericidal. It is odorless and non-toxic to bio-organic, and can effectively prevent or inhibit the internal and external corrosion of materials in industrial production, thus protecting the corresponding materials.

[0118] Thirdly, some embodiments of the present invention provide a functional composition comprising the above-mentioned multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, or the functional composition comprising a multifunctional corrosion inhibitor prepared by the above-mentioned method for preparing the multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid.

[0119] In this invention, the functional composition includes the multifunctional corrosion inhibitor described herein. The functional composition also possesses corrosion inhibition, scale inhibition, and bactericidal functions without the addition of other additives.

[0120] Fourthly, some embodiments of the present invention provide an application of the above-described functional composition in the field of carbon dioxide displacement of oil or gas.

[0121] In this invention, the functional composition is diluted with water to obtain a functional composition solution, which can be directly used in the field of carbon dioxide oil displacement and gas displacement without the need to add other compounds to form a compound for application.

[0122] In this invention, the functional composition is diluted with water to obtain a functional composition solution, which simultaneously possesses the functions of corrosion inhibition, scale inhibition, and bactericidal action. It can replace conventional functional compositions and be directly used in the field of carbon dioxide oil displacement or gas displacement without the need to add other compounds to form a compound functional composition, thus avoiding compatibility problems and antagonistic effects caused by the addition of multiple chemical agents.

[0123] The technical solution of the present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the reagents, materials and instruments used below are all conventional reagents, conventional materials and conventional instruments, all of which are commercially available, and the reagents and materials involved can also be synthesized by conventional synthesis methods.

[0124] Example 1

[0125] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0126] 1) At room temperature, 2.4 g (40 mmol) of acetic acid and 2.06 g (20 mmol) of N-(2-aminoethyl)-ethane-1,2-diamine were added to a reaction flask. 20 mL of p-xylene was added to the reaction flask. A water separator was connected to the mouth of the reaction flask. The mixture was heated to 100 °C and reacted for 3 h. The temperature was then increased to 200 °C and reacted for 15 h. After the reaction was completed, the heater was turned off and the reaction solution was cooled to room temperature. The product was separated by column chromatography. The reaction solution was packed into a column, and an eluent was prepared with petroleum ether:ethyl acetate in a ratio of 1:1. The reaction solution was washed to obtain a solution of intermediate 1. The solution was collected, and the solvent was removed by vacuum distillation to obtain 3.30 g of intermediate 1, with a yield of 98%.

[0127] 2) Add 2.7 g (10 mmol) of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 1.7 g (10 mmol) of intermediate 1, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0128] The reaction mixture was subjected to column chromatography to give 3.78 g of the compound, namely, the multifunctional corrosion inhibitor I-1, in 90% yield.

[0129] An example reaction formula for the above reaction is shown below:

[0130]

[0131] The structural analysis data of the multifunctional corrosion inhibitor I-1 are as follows:

[0132] High-resolution mass spectrometry: HRMS(ESI)[C 15 H 23 N3O9P] - The calculated value is 420.1177, and the test value is 420.1169.

[0133] MRI results: 1 H NMR (400MHz, CDCl3), δ3.75-3.44(m,8H),2.33-2.29(m,4H),2.26(s,3H),2.04-1.96(m,2H),1.91(s,3H).

[0134] Example 2

[0135] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0136] 1) At room temperature, 8.01 g (40 mmol) of dodecanoic acid and 2.06 g (20 mmol) of N-(2-aminoethyl)-ethane-1,2-diamine were added to a reaction flask. 20 mL of p-xylene was added to the flask. A water separator was connected to the mouth of the flask. The mixture was heated to 100 °C and reacted for 3 h. The temperature was then increased to 200 °C and reacted for 15 h. After the reaction was complete, the heater was turned off, and the reaction solution was cooled to room temperature. The product was separated by column chromatography. The reaction solution was packed into a column, and an eluent of dichloromethane:methanol in a ratio of 10:1 was prepared. The reaction solution was washed to remove impurities, followed by washing with methanol to obtain a methanol solution of intermediate 2. The solution was collected and distilled under reduced pressure to obtain 8.9 g of intermediate 2, with a yield of 99%.

[0137] 2) Add 2.7 g (10 mmol) of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0138] The reaction mixture was subjected to column chromatography to give 6.9 g of the compound, namely, the multifunctional corrosion inhibitor I-6, with a yield of 98%.

[0139] An example reaction formula for the above reaction is shown below:

[0140]

[0141] The structural analysis data of the multifunctional corrosion inhibitor I-6 are as follows:

[0142] High-resolution mass spectrometry: HRMS(ESI)[C 35 H 63 N3O9P] - The calculated value is 700.4313, and the tested value is 702.4306 [M]. - ].

[0143] MRI results: 1 H NMR (400MHz, CDCl3), δ3.70-3.56(m,8H), 3.45-2.88(m,8H), 2.54-2.06(m,9H), 1.58-1.51(m,3H), 1.31-1.24(m,26H), 0.87(t,J=7.2Hz,6H,2CH3).

[0144] Example 3

[0145] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0146] 1) At room temperature, 8.01 g (40 mmol) of dodecanoic acid and 2.06 g (20 mmol) of N-(2-aminoethyl)-ethane-1,2-diamine were added to a reaction flask. 20 mL of p-xylene was added to the flask. A water separator was connected to the mouth of the flask. The mixture was heated to 150 °C and reacted for 2 h. The temperature was then increased to 200 °C and reacted for 15 h. After the reaction was complete, the heater was turned off, and the reaction solution was cooled to room temperature. The product was separated by column chromatography. The reaction solution was packed into a column, and an eluent of dichloromethane:methanol in a ratio of 10:1 was prepared to wash the reaction solution and remove impurities. The solution was then washed with methanol to obtain a methanol solution of intermediate 2. The solution was collected and distilled under reduced pressure to obtain 8.9 g of intermediate 2, with a yield of 99%.

[0147] 2) Add 2.1 g (10 mmol) of di-tert-butyl phosphate to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h. The reaction mixture was subjected to column chromatography to obtain 4.8 g of compound, namely, multifunctional corrosion inhibitor I-9, with a yield of 75%.

[0148] An example reaction formula for the above reaction is shown below:

[0149]

[0150] The structural analysis data of the multifunctional corrosion inhibitor I-9 are as follows:

[0151] High-resolution mass spectrometry: HRMS(ESI)[C 36 H 73 N3O4P] + The calculated value is 642.5333, and the test value is 642.5338.

[0152] MRI results: 1 H NMR (400MHz, CDCl3), δ3.75-3.55(m,8H), 3.35-2.26(m,4H), 1.51-1.24(m,36H), 1.20(s,18H,6CH3), 0.88(t,J=7.2Hz,6H,2CH3).

[0153] Example 4

[0154] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0155] 1) At room temperature, 8.01 g (40 mmol) of dodecanoic acid and 2.06 g (20 mmol) of N-(2-aminoethyl)-ethane-1,2-diamine were added to a reaction flask. 20 mL of p-xylene was added to the flask. A water separator was connected to the mouth of the flask. The mixture was heated to 100 °C and reacted for 3 h. The temperature was then increased to 180 °C and reacted for 16 h. After the reaction was complete, the heater was turned off, and the reaction solution was cooled to room temperature. The product was separated by column chromatography. The reaction solution was packed into a column, and an eluent of dichloromethane:methanol in a ratio of 10:1 was prepared. The reaction solution was washed to remove impurities, followed by washing with methanol to obtain a methanol solution of intermediate 2. The solution was collected and distilled under reduced pressure to obtain 8.9 g of intermediate 2, with a yield of 99%.

[0156] 2) Add 2.5 g (10 mmol) of bis(p-methylphenyl)phosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0157] The reaction mixture was subjected to column chromatography to give 5.9 g of the compound, namely, the multifunctional corrosion inhibitor I-20, in a yield of 87%.

[0158] An example reaction formula for the above reaction is shown below:

[0159]

[0160] The structural analysis data of the multifunctional corrosion inhibitor I-20 are as follows:

[0161] High-resolution mass spectrometry: HRMS(ESI)[C 42 H 69 N3O2P] + The calculated value is 678.5122, and the test value is 678.5119.

[0162] MRI results: 1 H NMR (400MHz, CDCl3), δ7.72(d,J=7.6Hz,4H),7.34(d,J=7.6Hz,4H),3.75-3.46(m,8H), 2.37(s,6H,2CH3),2.34-2.26(m,4H),1.54-1.26(m,36H),0.88(t,J=7.2Hz,6H,2CH3).

[0163] Example 5

[0164] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0165] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0166] 2) Add 2.9 g (10 mmol) of bis-(p-chlorophenyl)phosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0167] The reaction mixture was subjected to column chromatography to give 6.7 g of compound I-21, i.e., a multifunctional corrosion inhibitor, with a yield of 93%.

[0168] An example reaction formula for the above reaction is shown below:

[0169]

[0170] The structural analysis data of the multifunctional corrosion inhibitor I-21 are as follows:

[0171] High-resolution mass spectrometry: HRMS(ESI)[C 40 H 63 Cl2N3O2P] + The calculated value is 718.4029, and the test value is 718.4033.

[0172] MRI results: 1 H NMR(400MHz, CDCl3), δ7.71(d,J=7.2Hz,4H),7.62(d,J=7.2Hz,4H),3.75-3.4 4(m,8H),3.34-2.98(m,4H),1.55-1.26(m,36H),0.88(t,J=7.2Hz,6H,2CH3).

[0173] Example 6

[0174] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0175] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0176] 2) Add 2.3 g (10 mmol) of dicyclohexylphosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0177] The reaction mixture was subjected to column chromatography to give 5.3 g of the compound, namely the multifunctional corrosion inhibitor I-22, in 80% yield.

[0178] An example reaction formula for the above reaction is shown below:

[0179]

[0180] The structural analysis data of the multifunctional corrosion inhibitor I-22 are as follows:

[0181] High-resolution mass spectrometry: HRMS(ESI)[C 42 H 69 N3O2P] + The calculated value is 662.5748, and the test value is 662.5747.

[0182] MRI results: 1 H NMR (400MHz, CDCl3), δ 1 H NMR (400MHz, CDCl3) δ3.71-3.57(m,8H),3.46-2.88(m,4H),1.88-1.78(m,2H),1.64-1.41(m,20H),1.53-1.27(m,36H),0.88(t,J=7.2Hz,6H,2CH3).

[0183] Example 7

[0184] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0185] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0186] 2) Add 1.9 g (10 mmol) of dichloroethylphosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0187] The reaction mixture was subjected to column chromatography to give 5.4 g of the compound, namely the multifunctional corrosion inhibitor I-23, in a yield of 87%.

[0188] An example reaction formula for the above reaction is shown below:

[0189]

[0190] The structural analysis data of the multifunctional corrosion inhibitor I-23 are as follows:

[0191] High-resolution mass spectrometry: HRMS(ESI)[C 32 H 63 Cl2N3O2P] + The calculated value is 622.4029, and the test value is 622.4031.

[0192] MRI results: 1 H NMR (400MHz, CDCl3), δ3.70-3.47(m,8H),3.64(t,J=7.2Hz,4H),3.42-2.87(m ,4H),1.92(t,J=7.2Hz,4H),1.53-1.27(m,36H),0.88(t,J=7.2Hz,6H,2CH3).

[0193] Example 8

[0194] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0195] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0196] 2) Add 1.2 g (10 mmol) of diethylphosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0197] The reaction mixture was subjected to column chromatography to give 5.1 g of compound I-24, i.e., a multifunctional corrosion inhibitor, in 92% yield.

[0198] An example reaction formula for the above reaction is shown below:

[0199]

[0200] The structural analysis data of the multifunctional corrosion inhibitor I-24 are as follows:

[0201] High-resolution mass spectrometry: HRMS(ESI)[C32 H 65 N3O2P] + The calculated value is 554.4809, and the test value is 554.4808.

[0202] MRI results: 1 H NMR (400MHz, CDCl3), δ3.72-3.47(m,8H),3.41-2.86(m,4H),1.72(q,J=7.2Hz,4H,2 CH2), 1.52-1.27 (m, 36H), 1.08 (t, J = 7.2Hz, 6H, 2CH3), 0.88 (t, J = 7.2Hz, 6H, 2CH3).

[0203] Example 9

[0204] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0205] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0206] 2) Add 1.3 g (10 mmol) of dimethoxyphosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0207] The reaction mixture was subjected to column chromatography to give 5.0 g of the compound, namely, the multifunctional corrosion inhibitor I-25, in a yield of 89%.

[0208] An example reaction formula for the above reaction is shown below:

[0209]

[0210] The structural analysis data of the multifunctional corrosion inhibitor I-25 are as follows:

[0211] High-resolution mass spectrometry: HRMS(ESI)[C 30 H 61 N3O2P] + The calculated value is 558.4394, and the test value is 558.4396.

[0212] MRI results: 1H NMR (400MHz, CDCl3) δ3.79 (s, 6H, 2CH3) 3.75-3.45 (m, 8H), 3.41-2.85 (m, 4H), 1.51-1.28 (m, 36H), 0.88 (t, J = 7.2Hz, 6H, 2CH3).

[0213] Example 10

[0214] The preparation method of the multifunctional corrosion inhibitor in this embodiment includes the following steps:

[0215] 1) An intermediate was prepared using the method described in step 1) of Example 2;

[0216] 2) Add 2.2 g (10 mmol) of diphenylphosphine oxide to the reaction flask and dissolve it in 10 mL of DMF. Then, add 2.4 g (15 mmol) of CDI dissolved in 10 mL of DMF dropwise to the reaction flask. After stirring at 25 °C for half an hour, add 4.5 g (10 mmol) of intermediate 2, connect the reflux condenser, heat the reaction to 160 °C and reflux for 10 h to obtain the reaction mixture.

[0217] The reaction mixture was subjected to column chromatography to give 6.1 g of the compound, namely, the multifunctional corrosion inhibitor I-26, in 94% yield.

[0218] An example reaction formula for the above reaction is shown below:

[0219]

[0220] The structural analysis data of the multifunctional corrosion inhibitor I-26 are as follows:

[0221] High-resolution mass spectrometry: HRMS(ESI)[C 40 H 65 N3O2P] + The calculated value is 650.4809, and the test value is 650.4812.

[0222] MRI results: 1 H NMR (400MHz, CDCl3), δ7.77-7.74(m,4H,Ar),7.51-7.47(m,6H,Ar),3.77-3.4 6(m,8H),3.40-2.84(m,4H),1.53-1.26(m,36H),0.88(t,J=7.2Hz,6H,2CH3).

[0223] Comparative Example 1

[0224] A corrosion inhibitor, scale inhibitor, and bactericide, comprising the following components in parts by weight:

[0225]

[0226] Comparative Example 2

[0227] The corrosion inhibitor of Comparative Example 2 is composed of the following components in parts by weight:

[0228]

[0229]

[0230] Performance testing

[0231] 1. Corrosion Inhibition Effect Test: N80 steel was selected and placed in simulated water (main components are shown in Table 1). The multifunctional corrosion inhibitors prepared in each example and the corrosion, scale, and bactericides in the comparative example were added. Under conditions of 40℃ and 4MPa carbon dioxide partial pressure, the mixture was statically coated in an autoclave for 7 days. The concentration of the multifunctional corrosion inhibitor or corrosion, scale, and bactericide was 200ppm. The average weight loss was recorded as W1; under the same conditions, the average weight loss was recorded as W0. The corrosion inhibition rate was calculated. The formula for calculating the corrosion inhibition rate is shown below:

[0232] Corrosion inhibition rate % = (W0-W1) / W0 × 100%.

[0233] Table 1. Main components of simulated water in corrosion inhibition effect test.

[0234]

[0235] 2. Scale Inhibition Effect Test: Referring to the QSY 126-2014 Technical Specification for Corrosion and Scale Inhibitors for Oilfield Water Treatment, Appendix A of the scale inhibition rate test only evaluates the scale inhibition rate of calcium carbonate. Specifically, after adding the multifunctional corrosion inhibitor from each example and the corrosion, scale, and bactericide from the comparative example, the concentration of the multifunctional corrosion inhibitor or the corrosion, scale, and bactericide was 200 ppm, and the scale inhibition rate was tested.

[0236] 3. Sterilization Efficacy Test: Referring to SY / T0532-2012 Oilfield Injection Water Bacterial Analysis Method (Extinction Dilution Method), the initial bacterial count was determined. The contact time between the bacterial solution and the agent was 1 hour. The bacterial count at the end of the experiment was measured, and the sterilization rate was calculated. The agent concentration was 200 ppm. The formula for calculating the sterilization rate is as follows:

[0237] Sterilization rate % = (initial bacterial count - bacterial count at the end of the experiment) / initial bacterial count × 100%.

[0238] Table 2 shows the performance of the multifunctional corrosion inhibitors in Examples 1-10 and the corrosion, scale, and bactericides in Comparative Examples 1-2.

[0239] Table 2 shows the performance of the multifunctional corrosion inhibitors in Examples 1-10 and the corrosion, scale, and bactericides in Comparative Examples 1-2.

[0240]

[0241]

[0242] As shown in Table 2, compared with Comparative Examples 1-2, the multifunctional corrosion inhibitor provided by the present invention has excellent corrosion inhibition, scale inhibition and bactericidal functions, which can avoid compatibility problems and antagonistic effects caused by the addition of multiple chemical agents.

[0243] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multifunctional corrosion inhibitor based on 1,2-disubstituted-4,5-dihydroimidazole organophosphorus carboxylic acid, characterized in that, The multifunctional corrosion inhibitor has the structure shown in Formula I: Among them, R 1 R represents at least one of hydrogen, deuterium, and alkyl groups; 2 and R 3 Each of the following groups independently represents at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl.

2. The multifunctional corrosion inhibitor according to claim 1, characterized in that, The R 1 It is at least one of alkyl groups having 1 to 20 carbon atoms.

3. The multifunctional corrosion inhibitor according to claim 1 or 2, characterized in that, R 2 and R 3 In this context, the halogen is at least one of F, Cl, and Br.

4. The multifunctional corrosion inhibitor according to claim 1 or 2, characterized in that, R 2 and R 3 In this context, the alkoxy group is at least one of alkoxy groups having 1 to 10 carbon atoms.

5. The multifunctional corrosion inhibitor according to claim 1 or 2, characterized in that, R 2 and R 3 In this context, the alkyl group is at least one of a straight-chain or branched alkyl group having 1 to 10 carbon atoms or a cycloalkyl group having 3 to 30 carbon atoms.

6. The multifunctional corrosion inhibitor according to claim 1 or 2, characterized in that, R 2 and R 3 In this context, the aryl group is at least one of aryl groups having 6 to 30 carbon atoms.

7. The multifunctional corrosion inhibitor according to claim 1 or 2, characterized in that, The R 2 and R 3 It is at least one of substituted alkyl, substituted alkoxy, and substituted aryl, wherein the substituent is at least one of deuterium, halogen, hydroxyl, cyano, carbonyl, carboxyl, ester, aryl, trifluoromethyl, aldehyde, alkyl, and alkoxy.

8. The multifunctional corrosion inhibitor according to claim 1, characterized in that, The multifunctional corrosion inhibitor has at least one of the structures shown in Formulas I-1 to I-26:

9. A method for preparing a multifunctional corrosion inhibitor according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1) Make organic carboxylic acid R 1 COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100–150 °C, followed by a dehydration cyclization reaction at 180–200 °C to obtain an intermediate; wherein the intermediate has the structure shown in Formula A; Step 2) The organophosphorus carboxylic acid and the condensation reagent are reacted in a second organic solvent, and then the intermediate obtained in step 1) is added and refluxed to obtain the multifunctional corrosion inhibitor.

10. The preparation method according to claim 9, characterized in that, In step 1), the organic carboxylic acid R 1 The molar ratio of COOH to N-(2-aminoethyl)-ethane-1,2-diamine is (2.0~2.2):

1.

11. The preparation method according to claim 9, characterized in that, In step 1), the organic carboxylic acid R 1 COOH,R 1 It is at least one of hydrogen, deuterium, and alkyl groups.

12. The preparation method according to claim 9, characterized in that, In step 2), the condensing agent includes at least one of N,N'-carbonyldiimidazole, dicyclohexylcarbodiimide, diisopropylcarbodiimide, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide. The organophosphorus carboxylic acid has the structure shown in formula B: Among them, R 2 and R 3 Each of the following can be independently represented as at least one of hydrogen, deuterium, halogen, hydroxyl, carbonyl, carboxyl, ester, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, and substituted or unsubstituted aryl. The molar ratio between the organophosphoric acid, the condensing agent, and the intermediate is 1:(1-1.6):

1.

13. The preparation method according to claim 9, characterized in that, In step 1), the first organic solvent includes at least one of p-xylene, m-xylene, mesitylene, N,N-dimethylformamide, and dimethyl sulfoxide; In step 2), the second organic solvent includes at least one of N,N-dimethylformamide and dimethyl sulfoxide.

14. The preparation method according to claim 9, characterized in that, In step 1), the organic carboxylic acid R1COOH and N-(2-aminoethyl)-ethane-1,2-diamine are reacted in a first organic solvent at 100-150°C. After all the reactants are consumed, a dehydration cyclization reaction is carried out at 180-200°C to obtain an intermediate.

15. The preparation method according to claim 9 or 14, characterized in that, In step 1), after the dehydration cyclization reaction is carried out at 180-200°C, the obtained dehydration cyclization product is subjected to column chromatography to obtain the intermediate.

16. The preparation method according to claim 9, characterized in that, In step 2), the organophosphorus carboxylic acid and the condensation reagent react in a second organic solvent at 20–30°C.

17. The preparation method according to claim 9, characterized in that, In step 2), the temperature of the reflux reaction is 155–180°C.

18. The preparation method according to claim 9, characterized in that, Step 2) further includes: after the reflux reaction is completed, the reflux product is subjected to column chromatography to obtain the multifunctional corrosion inhibitor.

19. A functional composition, characterized in that, The multifunctional corrosion inhibitor includes any one of claims 1-8, or the multifunctional corrosion inhibitor prepared by any one of claims 9-18.

20. The application of the functional composition of claim 19 in the field of carbon dioxide displacement of oil or gas.

Images