A one-pot homogeneous process for the large-scale production of 2-substituted benzimidazoles

Abstract

2-Substituted benzimidazoles and methods for preparing same are provided. A 2-substituted benzimidazole and a method for preparing the same are disclosed. The composition may include a compound or a salt thereof, a strong acid, and a carboxylic acid. The composition may be free of a polar aprotic solvent. The composition may be used to inhibit corrosion of metal surfaces in contact with an aqueous system, providing enhanced protection against corrosion of metals in aqueous systems. JPEG2024531068000030.jpg34128

Description

[Technical field]

[0001] The present disclosure relates generally to the synthesis of 2-substituted benzimidazoles and compositions thereof. More specifically, the present disclosure relates to a homogeneous process for synthesizing 2-substituted benzimidazoles and their use, for example, as corrosion inhibitors. [Background technology]

[0002] Benzimidazoles can be made using different synthetic routes. One common route is the acid-catalyzed condensation reaction between diamines and carboxylic acids. This route is primarily focused on obtaining solid benzimidazoles as isolated end products in moderate to good yields. Summary of the Invention [Problem to be solved by the invention]

[0003] These benzimidazoles are mainly synthesized with mineral acids, and the final product is precipitated by adjusting the pH to 7 or 8 using a base. The precipitated product is isolated by filtration and dried in an oven. Prior art synthesis methods suffer from several disadvantages, such as: 1) long reaction and process times, resulting in low throughput per batch; 2) yield loss from work-up and isolation steps; 3) isolation and subsequent drying steps require the installation of special equipment, which results in significant capital investment; 4) handling of the solid product, both as a wet cake and as a dry powder, involves significant material handling challenges, resulting in yield loss; and 5) the final solid product needs to be dried before being redissolved in a solvent for use in certain applications, such as corrosion protection.

[0004] Other uses of benzimidazoles include pharmaceutical and agrochemical applications. Polybenzimidazoles are known for their high strength and high temperature performance. Polybenzimidazoles are used in semiconductors, contact seals, wafer carriers, insulator bushings, thermal insulation, light emitting diodes, solar cells, fuel cells, and high performance protective clothing. Other uses include applications in the petrochemical and aerospace industries. [Means for solving the problem]

[0005] In some embodiments, the present disclosure provides a method for preparing a compound comprising: a strong acid; a carboxylic acid; and a compound of formula (I): [ka] [Wherein, X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, m is 1, 2, 3, or 4; R 1 is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 2 is absent or is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 3 is a bond or CHR 4 and R 4 However, hydrogen, halogen, and NR 5 R 6 OR 5 and Here, R 5 and R 6 each independently represents hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, and Z is independently selected from substituted or unsubstituted C, substituted or unsubstituted N, or any combination thereof, or a salt thereof, wherein the composition does not contain a polar aprotic solvent.

[0006] In some embodiments, the composition further comprises water.

[0007] In some embodiments, X is independently hydrogen or halogen, and R 1 is hydrogen and R 2 does not exist, R 3 is CHR 4 It is.

[0008] In some embodiments, R 3 is a bond and at least one Z is nitrogen.

[0009] In some embodiments, the compound or salt thereof has the formula (II): [ka] [In the formula, Y is independently hydrogen, halogen, or C 1~5 and n is 1, 2, 3, 4, or 5.

[0010] In some embodiments, the strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof.

[0011] In some embodiments, the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and any combination thereof.

[0012] In some embodiments, the composition comprises at least about 10% by weight of a carboxylic acid.

[0013] In some embodiments, the composition comprises a high temperature stable phase transfer catalyst.

[0014] In some embodiments, the carboxylic acid is acetic acid.

[0015] The present disclosure provides a process for making a compound of formula (V) or a salt thereof, comprising: [ka] A compound of formula (III) or a salt thereof, a compound of formula (IV) or a salt thereof, [ka] [Wherein, X is independently hydrogen, halogen, or C 1~5 is an alkyl group, m is 1, 2, 3, or 4; R 1 is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, substituted or unsubstituted C 4 ~C 6 is an aryl group, R 2 is absent or is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, substituted or unsubstituted C 4 ~C 6 is an aryl group, R 4 However, hydrogen, halogen, and NR 5 R 6 OR 5 and Here, R 5 and R 6 each independently represents hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R8 is hydrogen, halogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, substituted or unsubstituted C 5 ~C 6 Heteroaryl groups, substituted or unsubstituted C 4 ~C 6 Aryl group, or substituted or unsubstituted C 3 ~C 12

[0023] Also provided is a process for preparing a mixture comprising a carboxylic acid, a cycloalkyl group, a strong acid, a carboxylic acid, and a high temperature stable phase transfer catalyst, wherein the mixture is free of polar aprotic solvents, comprising heating the mixture, wherein the process is free of polar aprotic solvents.

[0016] In some embodiments, the strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof.

[0017] In some embodiments, the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and any combination thereof.

[0018] In some embodiments, the mixture comprises at least about 10% by weight of a carboxylic acid.

[0019] In some embodiments, the mixture is heated to a temperature of about 80°C to about 160°C.

[0020] The present disclosure also provides a process for preparing polybenzimidazole, comprising heating a mixture comprising diphenyl isophthalate and 3,3',4,4'-tetraaminodiphenyl, a strong acid, a carboxylic acid, and a high temperature stable phase transfer catalyst, wherein the process does not comprise a polar aprotic solvent.

[0021] In some embodiments, the strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof.

[0022] In some embodiments, the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and any combination thereof.

[0023] In some embodiments, the mixture comprises at least about 10% by weight of a carboxylic acid.

[0024] The present disclosure also provides a method for inhibiting corrosion comprising adding the composition of claim 1 to an industrial water system containing a metal surface.

[0025] The foregoing has outlined rather broadly the features and technical advantages of the present disclosure so that the detailed description of the embodiments that follow may be better understood. Additional features and advantages of the present disclosure will be described hereinafter which form the subject of the claims of this application. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure. It should also be appreciated by those skilled in the art that such equivalent embodiments do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Various embodiments are described below. The relationship and function of the various elements of the embodiments can be better understood by referring to the detailed description below. However, the embodiments are not limited to those exemplified below. In certain cases, details that are not necessary for understanding the embodiments disclosed herein may be omitted.

[0027] "Alkyl" refers to a straight chain or branched alkyl substituent. Examples of such substituents include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isoamyl, hexyl, and the like.

[0028] "Aryl" refers to an unsubstituted or substituted aromatic carbocyclic substituent, as generally understood in the art, and includes "C 6 ~C 10 The term "aryl" includes phenyl and naphthyl. It is understood that the term aryl also applies to cyclic substituents that are planar and contain 4n+2n electrons according to Huckel's rule.

[0029] "Cycloalkyl" refers to a cyclic alkyl substituent containing, for example, about 3 to about 8 carbon atoms, preferably about 4 to about 7 carbon atoms, and more preferably about 4 to about 6 carbon atoms. Examples of such substituents include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. Cyclic alkyl groups can be unsubstituted or can be further substituted with alkyl groups, such as methyl groups, ethyl groups, and the like.

[0030] “Halogen” or “halo” refers to F, Cl, Br, and I.

[0031] "Heteroaryl" refers to a monocyclic or bicyclic 5- or 6-membered ring system, where the heteroaryl group is unsaturated and satisfies Huckel's rule. Non-limiting examples of heteroaryl groups include furanyl, thiophenyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, isoxazolyl, oxazolyl, isothiazolyl, thiazolyl, 1,3,4-oxadiazol-2-yl, 1,2,4-oxadiazol-2-yl, 5-methyl-1,3,4-oxadiazole, 3-methyl-1,2,4-oxadiazole, pyridinyl, pyrimidinyl, pyrazinyl, triazinyl, benzofuranyl, benzothiophenyl, indolyl, quinolinyl, isoquinolinyl, benzimidazolyl, benzoxazolinyl, benzothiazolinyl, quinazolinyl, and the like.

[0032] "Oxo" refers to an oxygen atom double bonded to a carbon atom.

[0033] The compounds of the present disclosure may be substituted with suitable substituents. The term "suitable substituents" as used herein is intended to mean a chemically acceptable functional group, preferably a moiety that does not negate the activity of the compound. Such suitable substituents include, but are not limited to, halo groups, perfluoroalkyl groups, perfluoroalkoxy groups, alkyl groups, alkenyl groups, alkynyl groups, hydroxy groups, oxo groups, mercapto groups, alkylthio groups, alkoxy groups, aryl or heteroaryl groups, aryloxy or heteroaryloxy groups, aralkyl or heteroaralkyl groups, aralkoxy or heteroaralkoxy groups, HO-(C=O)- groups, heterocyclic groups, cycloalkyl groups, amino groups, alkyl and dialkylamino groups, carbamoyl groups, alkylcarbonyl groups, alkoxycarbonyl groups, alkylaminocarbonyl groups, dialkylaminocarbonyl groups, arylcarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups, and arylsulfonyl groups. In some embodiments, suitable substituents include halogen, unsubstituted C 1 ~C 12 Alkyl groups, unsubstituted C 4 ~C 6Aryl group or unsubstituted C 1 ~C 10 Those skilled in the art will recognize that many of the substituents can be substituted with further substituents.

[0034] As used herein, the term "high temperature stable phase transfer catalyst" refers to a phase transfer catalyst that remains stable at the temperatures and conditions required by the methods and processes described herein, particularly as it relates to the preparation of the compositions described herein. In this context, the term "remains stable" means that the phase transfer catalyst does not decompose or degrade and remains operationally functional at the temperatures and conditions described herein. In some embodiments, the high temperature stable phase transfer catalyst disclosed herein may be stable at temperatures greater than about 80°C to greater than about 250°C. For example, in certain embodiments, the high temperature stable phase transfer catalyst disclosed herein may remain stable at temperatures greater than about 80°C, about 90°C, 100°C, about 110°C, about 120°C, about 130°C, about 140°C, about 150°C, about 160°C, about 170°C, about 180°C, about 190°C, about 200°C, about 210°C, about 220°C, about 230°C, about 240°C, or about 250°C.

[0035] In some embodiments, a composition is disclosed that may include a compound of formula (I) or a salt thereof, a strong acid, and a carboxylic acid. The composition may be solvent-free. In some embodiments, the composition does not include a polar solvent. In some embodiments, the composition does not include an aprotic solvent. In some embodiments, the composition does not include a polar aprotic solvent. The compound of formula (I) has the formula shown below. [ka]

[0036] In some embodiments, X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, and m can be 1, 2, 3, or 4. In some embodiments, R 1 is hydrogen, substituted or unsubstituted C1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 In some embodiments, R 2 is absent, hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 In some embodiments, R 3 is a bond or CHR 4 In some embodiments, R 4 is hydrogen, halogen, NR 5 R 6 OR 5 In some embodiments, R 5 and R 6 are each independently hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 It is an aryl group.

[0037] R 2 When present, counterions may be included and may include halides, such as chloride, bromide, and iodide, or other counterions, such as, for example, methanesulfonate, sulfate, acetate, and formate.

[0038] The X substituent or substituents can occupy any available position on the benzimidazole ring. Thus, in certain embodiments, the X substituent or substituents can be located at the 4-, 5-, 6-, and / or 7-position of the benzimidazole. In certain embodiments, the X substituent is at the 5-position.

[0039] The number m of X substituents can be 1, 2, 3, or 4. When m is 2, 3, or 4, the X substituents can occupy any open positions and can be positioned ortho, meta, or para to each other.

[0040] In certain embodiments, the salt of the compound of formula (I) can be any salt, such as chloride, bromide, iodide, sulfate, fluoride, perchlorate, acetate, trifluoroacetate, phosphate, nitrate, carbonate, bicarbonate, formate, chlorate, bromate, chlorite, thiosulfate, oxalate, cyanide, cyanate, tetrafluoroborate, etc. In some embodiments, the salt of the compound of formula (I) can be a hydrochloride or sulfate salt.

[0041] In some embodiments, Z is independently selected from substituted or unsubstituted C, substituted or unsubstituted N, or any combination thereof.

[0042] In some embodiments, Z is CH or N.

[0043] In some embodiments, X is hydrogen and m is 4.

[0044] In some embodiments, R 1 is hydrogen.

[0045] In some embodiments, R 2 does not exist.

[0046] In some embodiments, R 3 is a bond.

[0047] In some embodiments, R 3 is CHR 4 It is.

[0048] In some embodiments, R 4 is hydrogen.

[0049] In some embodiments, R 4 is a halogen.

[0050] In some embodiments, R 4 is NR 5 R 6 It is.

[0051] In some embodiments, R 4 OR 5 It is.

[0052] In some embodiments, R 5 is a substituted or unsubstituted C 1 ~C 12 It is an alkyl group.

[0053] In some embodiments, R 5 is hydrogen.

[0054] In some embodiments, R 5 is a substituted or unsubstituted C 4 ~C 6 It is an aryl group.

[0055] In some embodiments, one Z is N and the remainder are CH. In some embodiments, at least two Z are N and the remainder are CH. In some embodiments, at least three Z are N and the remainder are CH. In some embodiments, at least four Z are N and the remainder are CH. In some embodiments, all Z are N or all Z are CH.

[0056] In some embodiments, R 3 is a bond and at least one Z is N.

[0057] In some embodiments, X is independently hydrogen or halogen, and R 1 is hydrogen and R 2 does not exist, R 3 is CHR 4 It is.

[0058] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0059] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0060] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0061] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0062] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0063] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0064] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0065] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0066] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0067] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0068] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0069] In some embodiments, the compound of formula (I) or salt thereof is [ka] It is.

[0070] In some embodiments, the composition comprises a compound represented by formula (Ia): [ka] [Wherein, X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, m is 1, 2, 3, or 4, and R 1 is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 2 is absent or is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 3 is a bond or CHR 4 or a salt thereof.

[0071] In some embodiments, the compound or salt thereof has the formula (II): [ka] [Wherein, X, m, and R 3 X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, m is 1, 2, 3, or 4, and R 3 is a bond or CHR 4 and Y is independently hydrogen, halogen, or C 1~5 and n is 1, 2, 3, 4, or 5.

[0072] In some embodiments, Y is hydrogen.

[0073] In some embodiments, Y is independently hydrogen and halogen.

[0074] As described herein, m can be 1, 2, 3, or 4. When m is 2, 3, or 4, the X substituents can occupy any open positions and can be positioned ortho, meta, or para to each other. The number n of Y substituents can be 1, 2, 3, or 4. When n is 2, 3, or 4, the Y substituents can occupy any open positions and can be positioned ortho, meta, or para to each other.

[0075] In some embodiments, the concentration of the compound of Formula (I), Formula (Ia), or Formula (II) or a salt thereof in the composition can be in the range of about 1% to about 50% by weight, about 5% to about 50% by weight, about 10% to about 50% by weight, about 15% to about 50% by weight, about 20% to about 50% by weight, about 20% to about 45% by weight, about 25% to about 45% by weight, or about 25% to about 40% by weight.

[0076] In some embodiments, the strong acid can be a strong inorganic acid, a strong organic acid, or any combination thereof. In some embodiments, the strong acid is a strong inorganic acid. In some embodiments, the strong acid is a strong organic acid. As used herein, "strong" refers to an acid having a pKa of less than about 1.

[0077] In some embodiments, the strong acid may be selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof.

[0078] In some embodiments, the strong acid can be sulfuric acid.

[0079] In some embodiments, the strong acid can be hydrochloric acid.

[0080] In some embodiments, the strong acid can be nitric acid.

[0081] In some embodiments, the strong acid can be methanesulfonic acid.

[0082] In some embodiments, the strong acid can be sulfamic acid.

[0083] In some embodiments, the strong acid can be p-toluenesulfonic acid.

[0084] In some embodiments, the strong acid can be hydrobromic acid.

[0085] The amount of the strong acid in the composition may be in the range of about 10% by weight to about 80% by weight. For example, the amount of the strong acid in the composition may be in the range of about 10% by weight to about 70% by weight, about 10% by weight to about 60% by weight, about 10% by weight to about 50% by weight, about 10% by weight to about 40% by weight, about 10% by weight to about 30% by weight, about 10% by weight to about 20% by weight, about 15% by weight to about 20% by weight, about 15% by weight to about 25% by weight, or about 15% by weight to about 30% by weight.

[0086] As used herein, "carboxylic acid" refers to an organic compound that contains a carboxyl group. In some embodiments, the carboxylic acid is a substituted or unsubstituted C 1 ~C 32 It may be an alkyl carboxylic acid.

[0087] In some embodiments, the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and any combination thereof.

[0088] In some embodiments, the carboxylic acid is acetic acid.

[0089] In some embodiments, the composition comprises more than 5% by weight of a carboxylic acid, for example at least about 6% by weight, at least about 7% by weight, at least about 8% by weight, at least about 9% by weight, or at least about 10% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 12% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 15% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 5% by weight of a carboxylic acid, for example at least about 6% by weight, at least about 7% by weight, at least about 8% by weight, at least about 9% by weight, at least about 10% by weight, 12% by weight, or 15% by weight of a carboxylic acid to about 70% by weight, about 60% by weight, about 50% by weight, about 40% by weight, about 30% by weight, or about 20% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% by weight of a carboxylic acid to about 70% by weight of a carboxylic acid.

[0090] In some embodiments, the composition comprises at least about 10% to about 50% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% to about 50% by weight of a carboxylic acid. In some embodiments, the composition comprises at least about 10% to about 40% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% to about 40% by weight of a carboxylic acid. In some embodiments, the composition comprises at least about 10% to about 30% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% to about 30% by weight of a carboxylic acid. In some embodiments, the composition comprises at least about 10% to about 20% by weight of a carboxylic acid. In some embodiments, the composition comprises more than 10% to about 20% by weight of a carboxylic acid.

[0091] The inventors have unexpectedly found that the absence of solvents such as polar solvents, aprotic solvents, and / or polar aprotic solvents, and the inclusion of carboxylic acids such as acetic acid, does not adversely affect the overall stability of the formulation.By not including the aforementioned solvents, the formulation also exhibits an improved environmental profile.Extensive experiments have been performed to determine that carboxylic acids present in amounts greater than 5% by weight, such as at least about 10% by weight, achieve the desired low temperature (freeze-thaw) stability in addition to other benefits.

[0092] The compositions disclosed herein may not include a solvent, a polar solvent, an aprotic solvent, and / or a polar aprotic solvent, and any method steps disclosed herein may not include the addition of a solvent, a polar solvent, an aprotic solvent, and / or a polar aprotic solvent. Examples of polar aprotic solvents include acetonitrile, N,N-dimethylformamide, acetone, dimethylsulfoxide, sulfolane, N-methylpyrrolidinone, methylsulfonylmethane, chlorobenzene, o-dichlorobenzene, nitromethane, and ionic liquids. Any of these polar aprotic solvents or any other polar aprotic solvents may be excluded from the compositions and method steps disclosed herein.

[0093] In some embodiments, the composition may include a high temperature stable phase transfer catalyst.

[0094] In some embodiments, the high temperature stable phase transfer catalyst is selected from the group consisting of alkylguanidinium salts, arylguanidinium salts, alkylphosphonium salts, arylphosphonium salts, peralkylated phosphazenium salts, and any combination thereof. Examples of high temperature stable phase transfer catalysts include, but are not limited to, hexaethylguanidinium chloride, tetraphenylphosphonium bromide, hexaalkylphosphonium salts, hexadecyltributylphosphonium bromide, or any combination thereof.

[0095] In some embodiments, the composition may contain water. For example, the composition may contain about 5% to about 95% by weight of water, such as about 5% to about 50% by weight, about 5% to about 25% by weight, about 10% to about 50% by weight, or about 20% to about 75% by weight of water.

[0096] In some embodiments, the composition may be a homogeneous mixture, hi some embodiments, the composition may be a solution.

[0097] In some embodiments, the composition may include a phenylenediamine compound. When the composition includes a phenylenediamine compound, it is present in the composition in an amount of about 0.0001% to about 0.1% by weight. In some embodiments, the amount of the phenylenediamine compound in the composition may be less than about 0.1% by weight. In some embodiments, the amount of the phenylenediamine compound in the composition may be less than about 0.9%, about 0.8%, about 0.7%, about 0.6%, about 0.5%, about 0.4%, or about 0.3% by weight.

[0098] In another embodiment, a process for making a compound of formula (V) or a salt thereof is disclosed. [ka]

[0099] The process may include heating a mixture comprising a compound of formula (III) or a salt thereof, a compound of formula (IV) or a salt thereof, a strong acid, a carboxylic acid, and a high temperature stable phase transfer catalyst. The process may not include adding a polar solvent, an aprotic solvent, and / or a polar aprotic solvent. [ka]

[0100] For formula (III-V), X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, m is 1, 2, 3, or 4, and R 1 is hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 2 is absent, hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 4is hydrogen, halogen, NR 5 R 6 OR 5 and R 8 is hydrogen, halogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, substituted or unsubstituted C 5 ~C 6 Heteroaryl groups, substituted or unsubstituted C 4 ~C 6 Aryl group, or substituted or unsubstituted C 3 ~C 12 R may be a cycloalkyl group. 5 and R 6 are each independently hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 It is an aryl group.

[0101] In some embodiments, R 8 is a substituted or unsubstituted C 5 ~C 6 It is a heteroaryl group.

[0102] In some embodiments, R 8 is a substituted or unsubstituted C 5 ~C 6 Heteroaryl group, or substituted or unsubstituted C 4 ~C 6 It is an aryl group.

[0103] In some embodiments, R 8 is a substituted or unsubstituted C 4 ~C 6 It is an aryl group.

[0104] In some embodiments, R 8 is a substituted or unsubstituted C 6 It is a heteroaryl group.

[0105] In some embodiments, R 8 is a substituted or unsubstituted C 6It is an aryl group.

[0106] In some embodiments, the reaction product of the compounds of formula (III) and (IV) may be further reacted in a post-modification step to form R 1 In the case of 2 In the case of the above, a substituent may be added.

[0107] The synthesis process disclosed herein has many advantages over the prior art. Compared to conventional synthesis methods, the final product can be obtained in higher yield. The final product can also be in a homogeneous liquid form, which facilitates product transfer and formulation while minimizing yield loss. Because the final product can be in a homogeneous liquid form, solids separation processes and equipment are not required, leading to significant cost savings.

[0108] In certain embodiments, a process for making a compound of formula (I) or a salt thereof is disclosed. [ka]

[0109] The process may include heating a mixture comprising a compound of formula (III) or a salt thereof, a compound of formula (VI) or a salt thereof, a strong acid, a carboxylic acid, and a high-temperature stable phase transfer catalyst. The process may not include adding a polar solvent, an aprotic solvent, and / or a polar aprotic solvent. The mixture may not include a polar solvent, an aprotic solvent, and / or a polar aprotic solvent. [ka]

[0110] For formulas (I), (III), and (VI), X is independently hydrogen, halogen, or substituted or unsubstituted C 1~5 is an alkyl group, m is 1, 2, 3, or 4, and R 1 is hydrogen, substituted or unsubstituted C 1 ~C 12Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 2 is absent, hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 is an aryl group, R 3 is a bond or CHR 4 and R 4 is hydrogen, halogen, NR 5 R 6 OR 5 and R 5 and R 6 are each independently hydrogen, substituted or unsubstituted C 1 ~C 12 Alkyl group, or substituted or unsubstituted C 4 ~C 6 aryl group, and Z is independently selected from substituted or unsubstituted C, substituted or unsubstituted N, or any combination thereof. In some embodiments, R 7 is oxo or COOH.

[0111] In some embodiments, R 7 is COOH.

[0112] In some embodiments, R 7 is oxo.

[0113] Any acid and any equivalent described in this disclosure may be used in the process of making the compounds or salts of formulas (I) and (V).

[0114] In some embodiments, the concentration of the strong acid in the mixture or composition may range from about 10% to about 80% by weight. For example, the amount of strong acid may range from about 10% to about 70% by weight, about 10% to about 60% by weight, about 10% to about 50% by weight, about 10% to about 40% by weight, about 10% to about 30% by weight, about 10% to about 20% by weight, about 15% to about 20% by weight, about 15% to about 25% by weight, or about 15% to about 30% by weight.

[0115] Any of the high temperature stable phase transfer catalysts described in this disclosure and any equivalents may be used in the process of making the compounds or salts of formulas (I) and (V).

[0116] In some embodiments, the concentration of the high temperature stable phase transfer catalyst in the mixture or composition can range from about 0.001% to about 30% by weight. In some embodiments, the concentration of the high temperature stable phase transfer catalyst in the mixture or composition can range from about 0.001% to about 25% by weight, about 0.001% to about 20% by weight, about 0.01% to about 25% by weight, about 0.1% to about 25% by weight, about 0.5% to about 25% by weight, about 1% to about 25% by weight, about 1% to about 20% by weight, or about 1% to about 25% by weight. In some embodiments, the concentration of the polar aprotic solvent in the mixture can be 1%, 5%, or 10% by weight.

[0117] In some embodiments, the process of making a compound of formula (I) or (V) or a salt thereof can include heating the mixture to a temperature of about 80° C. to about 160° C. In some embodiments, the mixture can be heated to a temperature of about 80° C. to about 120° C., about 90° C. to about 120° C., or about 90° C. to about 110° C. The mixture can be heated using any means suitable for raising the temperature to a suitable level. The heating system can be fuel-based, electrical-based, or steam-based. For example, steam can be passed through a tube that contacts the mixture.

[0118] In some embodiments, the mixture may be heated for a period ranging from about 30 minutes to about 12 hours. In some embodiments, the mixture may be heated for a period ranging from about 1 hour to about 12 hours, from about 2 hours to about 12 hours, from about 2 hours to about 10 hours, from about 4 hours to about 10 hours, or from about 5 hours to about 10 hours.

[0119] In some embodiments, the mixture can have an active agent concentration of about 1 to about 50% by weight, where "active agent concentration" refers to the concentration of the compounds of Formula (III) and Formula (IV) or the compounds of Formula (III) and Formula (VI). In some embodiments, the mixture can have an active agent concentration of about 10% to about 50% by weight, about 20% to about 50% by weight, about 20% to about 45% by weight, about 25% to about 45% by weight, or about 25% to about 40% by weight.

[0120] In some embodiments, disclosed are compositions prepared according to the processes described in this disclosure. The processes for making the compounds or salts of formula (I) or (V) can produce homogeneous compositions that can be used for corrosion inhibition without further purification.

[0121] In some embodiments, the compositions of the present disclosure may be used in medicine. In some embodiments, the compositions of the present disclosure may be used in pesticides. In some embodiments, the compositions of the present disclosure may be used to inhibit corrosion.

[0122] In some embodiments, a method for preventing corrosion is disclosed.

[0123] The present disclosure provides methods of using heterocyclic compounds and formulations containing heterocyclic compounds that are particularly useful for inhibiting corrosion of metal components in industrial water systems. Benzimidazoles that can undergo chelation with metals when added to aqueous systems provide excellent metal corrosion resistance. Specifically, adding benzimidazoles substituted with 2-pyridyl or benzyl alcohol to aqueous systems in contact with metal surfaces provides excellent corrosion inhibition for metals such as copper. Furthermore, while benzotriazoles and benzimidazoles are generally unstable in the presence of oxidizing halogen compounds, the compounds of the present disclosure can undergo 1,2-chelation with metals to provide exemplary protection of metals in the presence of oxidizing halogen compounds. Specifically, 2-(2-pyridyl)benzimidazole provides better protection against corrosion in the presence of oxidizing halogen compounds than benzimidazole, 2-phenylbenzimidazole, and tolyltriazole. Without wishing to be bound by any particular theory, it is believed that the compounds of the present disclosure form a protective film that is essentially impenetrable to common oxyhalogen compounds through bidentate chelation of the corrosion inhibitor with the metal surface. Thus, in certain embodiments, the methods of the present disclosure provide protection against metal corrosion in aqueous systems using oxyhalogen compounds as biocides.

[0124] In some embodiments, the present disclosure provides a method for inhibiting corrosion of a metal surface in contact with an aqueous system. The method can include adding any of the compositions described in the present disclosure to the aqueous system. For example, the composition can include a compound of formula (I), a strong acid, and a carboxylic acid. The composition can be free of polar aprotic solvents, polar solvents, and / or aprotic solvents.

[0125] "Industrial water system" means any system in which water is circulated as its primary component. Non-limiting examples of "industrial water systems" include cooling systems, boiler systems, heating systems, membrane systems, papermaking systems, or any other system in which water is circulated.

[0126] Compounds of formula (I), (Ia), and (II) can provide corrosion protection for any metal or metal alloy, including, but not limited to, copper, iron, silver, steel (e.g., galvanized steel), and aluminum. In certain embodiments, compounds of formula (I), (Ia), or (II) are added to aqueous systems in contact with metal surfaces including copper to inhibit metal corrosion. In certain embodiments, compounds of formula (I), (Ia), or (II) are added to aqueous systems in contact with metal surfaces including copper alloys to inhibit metal corrosion. In certain embodiments, copper is complexed with one or more heteroatoms in compounds of formula (I), (Ia), or (II). In certain embodiments, copper is complexed with one or more heteroatoms in compounds of formula (I), (Ia), or (II). Copper has a wide range of applications, including use as copper piping and copper tubes in plumbing and industrial machinery. Copper and copper alloys are well known for use in cooling water systems and boiler water systems.

[0127] The compounds of formula (I), (Ia), and (II) can be used to protect any copper alloy, including bronze and brass. Bronze typically contains copper and tin, but may contain other elements, including aluminum, manganese, silicon, arsenic, and phosphorus. Brass contains copper and zinc and is commonly used in the piping of water boiler systems. In certain embodiments, compounds of formula (I), (Ia), or (II) are added to aqueous systems in contact with metal surfaces that contain bronze to inhibit metal corrosion. In certain embodiments, compounds of formula (I), (Ia), or (II) are added to aqueous systems in contact with metal surfaces that contain brass, such as Admiralty brass, to inhibit metal corrosion. In certain embodiments, compounds of formula (I), (Ia), or (II) are added to aqueous systems in contact with metal surfaces that contain copper-nickel alloys to inhibit metal corrosion.

[0128] In certain embodiments, the compounds of formula (I), (Ia), or (II) inhibit the corrosion of mild steel. In certain embodiments, the compounds of formula (I), (Ia), or (II) inhibit the corrosion of metal alloys, including, but not limited to, galvanized steel, stainless steel, cast iron, nickel, and combinations thereof. Without wishing to be bound by any particular theory, it is hypothesized that the compounds of formula (I), (Ia), and (II) inactivate Cu(II) in solution and prevent the formation of a galvanic cell on the steel surface. Thus, in certain embodiments, the compounds of formula (I), (Ia), or (II) inhibit the corrosion of mild steel.

[0129] Although the compounds of formula (I), (Ia), and (II) can be added to the aqueous system at any dosage rate, the compounds of formula (I), (Ia), and (II) are generally added to the aqueous system at a dosage rate of about 0.01 ppm to about 500 ppm. In certain embodiments, the compounds of formula (I), (Ia), or (II) are added to the aqueous system at a dosage rate of about 0.01 ppm to about 100 ppm. In certain embodiments, the compound of formula (I), (Ia), or (II) is present at a concentration of from about 0.01 ppm to about 100 ppm, from about 0.01 ppm to about 75 ppm, from about 0.01 ppm to about 50 ppm, from about 0.01 ppm to about 25 ppm, from about 0.01 ppm to about 10 ppm, from about 0.01 ppm to about 5 ppm, from about 0.1 ppm to about 100 ppm, from about 0.1 ppm to about 75 ppm, from about 0.1 ppm to about 50 ppm, from about 0.1 ppm to about 25 ppm, pm, about 0.1 ppm to about 10 ppm, about 0.1 ppm to about 5 ppm, about 1 ppm to about 100 ppm, about 1 ppm to about 75 ppm, about 1 ppm to about 50 ppm, about 1 ppm to about 25 ppm, about 1 ppm to about 10 ppm, about 5 ppm to about 100 ppm, about 10 ppm to about 100 ppm, about 25 ppm to about 100 ppm, about 50 ppm to about 100 ppm, or about 80 ppm to about 100 ppm.

[0130] In certain embodiments, the aqueous system is a cooling water system. The cooling water system can be a closed loop cooling water system or an open loop cooling water system. In certain embodiments, the compound of formula (I), (Ia), or (II) is added to the closed loop cooling water system at a dosage rate of about 0.01 ppm to about 200 ppm. In certain embodiments, the compound of formula (I), (Ia), or (II) is added to the open loop cooling water system at a dosage rate of about 0.01 ppm to about 20 ppm.

[0131] The compounds of formula (I), (Ia), and (II) are contacted with the metal surface by any suitable method. In certain embodiments, the solution of the compound of formula (I), (Ia), or (II) is contacted with the metal surface by immersion, spraying, or other coating techniques. In certain embodiments, the solution of the compound of formula (I), (Ia), or (II) is introduced into the water of the aqueous system by any conventional method and fed to the aqueous system on a periodic or continuous basis.

[0132] In some embodiments, the compositions disclosed herein may include a fluorescent organic compound. In certain embodiments, the fluorescent organic compound may be selected from rhodamine or a derivative thereof, an acridine dye, fluorescein or a derivative thereof, and combinations thereof. In certain embodiments, the compositions disclosed herein may include a fluorescently tagged polymer.

[0133] Those skilled in the art will understand that the compounds of formula (I), (Ia), or (II) can be added to the aqueous system alone or in combination with other corrosion inhibitors or treatment chemicals. Multiple corrosion inhibitors, including two or more compounds of formula (I), (Ia), and / or formula (II), can be added as a combined corrosion inhibitor formulation, or the corrosion inhibitors can be added separately. Furthermore, the compounds of formula (I), (Ia), or (II) can be added to the aqueous system in combination with various additional corrosion inhibitors, including, but not limited to, triazoles, benzotriazoles (e.g., benzotriazole or tolyltriazole), benzimidazoles, orthophosphates, polyphosphates, phosphonates, molybdates, silicates, oximes, and nitrates. The compounds of formulae (I), (Ia), and (II) may also be added to aqueous systems in combination with a variety of additional additives, such as treatment polymers, antimicrobial agents, antiscaling agents, colorants, fillers, buffers, surfactants, viscosity modifiers, chelating agents, dispersants, odor removers, masking agents, oxygen scavengers, and indicating dyes.

[0134] In other embodiments, the process for making polybenzimidazole may include heating a mixture having diphenyl isophthalate, 3,3',4,4'-tetraaminodiphenyl, a carboxylic acid, a strong acid, and a high-temperature stable phase transfer catalyst. The process may not include the addition of a polar solvent, an aprotic solvent, and / or a polar aprotic solvent. The strong acid, the carboxylic acid, and the high-temperature stable phase transfer catalyst are as described in this disclosure.

[0135] Polybenzimidazoles are known for their high strength and high temperature performance.The polybenzimidazoles synthesized according to the process disclosed herein can be used in, for example, semiconductors, contact seals, wafer carriers, insulator bushings, thermal insulation, light emitting diodes, solar cells, fuel cells, and high performance protective clothing.Other uses include applications in the petrochemical and aerospace industries. EXAMPLES

[0136] Working Example

[0137] Example 1

[0138] A flask equipped with a magnetic stirrer, reflux condenser, and temperature probe was charged with methanesulfonic acid and water. To this, DL-mandelic acid (1 equivalent) and 1,2-phenylenediamine (1 equivalent) were added and the contents of the flask were refluxed at about 100-110°C for about 6-8 hours. After completion of the reaction, acetic acid (about 10% by weight) was added and reflux was maintained for an additional 1-3 hours. After workup, an additional amount of water was added to adjust the active material to about 20%. Purity and residual OPD analysis were performed using NMR and HPLC. This process produced a homogeneous solution.

[0139] Example 2

[0140] A flask equipped with a magnetic stirrer, reflux condenser, and temperature probe was charged with methanesulfonic acid and water. To this was added DL-mandelic acid (1-1.05 equivalents) and 1,2-phenylenediamine (1 equivalent) and the contents of the flask were refluxed at about 100 to about 110°C for about 6 to about 8 hours. After completion of the reaction, the specified amount of acid was added and reflux was maintained for about an additional 1 to 3 hours. An additional amount of water was then added to adjust the active material to about 20%. Purity and residual OPD analysis was performed using NMR and HPLC.

[0141] The samples were subjected to 10 rounds of freeze-thaw stability testing. Each sample was frozen at approximately -10 o F freezer and allowed to freeze for 48 hours. The frozen samples were allowed to sit at ambient temperature for the next 48 hours until the frozen material was completely thawed. This process was repeated 10 times and the samples were checked for any precipitation. The % activity of all samples was around 20% with various amounts of acetic acid (0%, 5%, 10% and 40%) or 10% of the various acids. The results are shown in Table 1.

[0142] [Table 1]

[0143] As can be seen from Table 1, only about 10% and about 40% by weight acetic acid provided homogenous samples without significant precipitation or crystallization.

[0144] All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. The present invention can be embodied in many different forms, and certain preferred embodiments of the present invention are described in detail herein. The present disclosure is an exemplification of the principles of the present invention, and is not intended to limit the invention to the specific embodiments illustrated. It is to be noted that, unless expressly stated otherwise, the term "a" is intended to include "at least one" or "one or more." For example, "strong acid" is intended to include "at least one strong acid" or "one or more strong acids."

[0145] Any ranges expressed in either absolute or approximate terms are intended to encompass both, and any definitions used herein are intended to be illustrative, not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein should be understood to encompass any and all subranges subsumed therein, including all fractional and whole values.

[0146] Any composition disclosed herein can comprise, consist of, or consist essentially of any element, component, and / or ingredient disclosed herein, or any combination of two or more of the elements, components, or ingredients disclosed herein.

[0147] Any method disclosed herein may comprise, consist of, or consist essentially of any method steps disclosed herein, or any combination of two or more of the method steps disclosed herein.

[0148] The transitional phrase "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements, components, ingredients, and / or method steps.

[0149] The transitional phrase "consisting of" excludes any element, component, ingredient, and / or method step not specified in the claim.

[0150] The transitional phrase "consisting essentially of" limits the scope of the claim to certain elements, components, ingredients, and / or steps, and those that do not materially affect the basic and novel characteristics of the claimed invention.

[0151] Unless otherwise specified, all molecular weights referred to herein are weight average molecular weights and all viscosities were measured at 25° C. using neat (undiluted) polymer.

[0152] As used herein, the term "about" refers to a cited value that is within error resulting from the standard deviation found in their respective testing measurements; where such error cannot be determined, "about" may refer, for example, to within 5% of the cited value.

[0153] Moreover, the present invention encompasses all possible combinations of any or all of the various embodiments described herein. It should also be understood that various changes and modifications to the preferred embodiments of the present invention described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. Accordingly, such changes and modifications are intended to be covered by the appended claims.

Claims

1. A composition comprising a strong acid, a carboxylic acid, and a compound of the following formula (I) or a salt thereof, wherein: 【Chemical 1】 In the formula, X is, independently, hydrogen, halogen, or a substituted or unsubstituted C １～５ alkyl group, m is 1, 2, 3, or 4, R １ is hydrogen, a substituted or unsubstituted C １ ~C １２ alkyl group, or a substituted or unsubstituted C ４ ~C ６ aryl group, and R ２ is absent, hydrogen, substituted or unsubstituted C １ to C １２ alkyl group, or substituted or unsubstituted C ４ to C ６ aryl group, and R ３ is a bond or CHR ４ and R ４ is hydrogen, halogen, NR ５ R ６ or OR ５ and Here, R ５ and R ６ are each independently hydrogen, a substituted or unsubstituted C １ to C １２ alkyl group, or a substituted or unsubstituted C ４ to C ６ aryl group, and Z is independently selected from substituted or unsubstituted C, substituted or unsubstituted N, or any combination thereof, The composition does not contain an aprotic polar solvent.

2. The composition according to claim 1, further comprising water.

3. X is independently hydrogen or a halogen, R １ is hydrogen, and R ２ does not exist R ３ is CHR ４ The composition according to claim 1 or 2, wherein

4. R ３ The composition according to claim 1 or 2, wherein R is a bond and at least one Z is nitrogen.

5. The compound or its salt is of formula (II), wherein: [Chemical Formula 2] In the formula, Y is independently hydrogen, halogen, or C １～５ an alkyl group, and n is 1, 2, 3, 4, or 5, the composition according to claim 1 or 2.

6. The strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof, according to claim 1 or 2.

7. The carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, and any combination thereof, according to claim 1 or 2.

8. The composition according to claim 1 or 2, wherein the composition contains at least about 10% by weight of the carboxylic acid.

9. The composition according to claim 1 or 2, further comprising a high-temperature stable phase transfer catalyst.

10. The composition according to claim 1 or 2, wherein the carboxylic acid is acetic acid.

11. A process for preparing a compound of formula (V) or a salt thereof, the process comprising heating a mixture comprising a compound of formula (III) or a salt thereof, a compound of formula (IV) or a salt thereof, a strong acid, a carboxylic acid, and a high-temperature stable phase transfer catalyst, wherein: [Chemical Formula 3] In the formula, 【Chemical 4】 The mixture does not contain an aprotic polar solvent, X is independently hydrogen, halogen, or C １～５ an alkyl group, m is 1, 2, 3, or 4, R １ is hydrogen, a substituted or unsubstituted C １ ~C １２ alkyl group, a substituted or unsubstituted C ４ ~C ６ aryl group, and R ２ is absent, or is hydrogen, a substituted or unsubstituted C １ ~C １２ alkyl group, or a substituted or unsubstituted C ４ ~C ６ aryl group, and R ４ is hydrogen, halogen, NR ５ R ６ or OR ５ and Here, R ５ and R ６ are each independently hydrogen, a substituted or unsubstituted C １ to C １２ alkyl group, or a substituted or unsubstituted C ４ to C ６ aryl group, and R ８ is hydrogen, halogen, substituted or unsubstituted C １ to C １２ alkyl group, substituted or unsubstituted C ５ to C ６ heteroaryl group, substituted or unsubstituted C ４ to C ６ aryl group, or substituted or unsubstituted C ３ to C １２ cycloalkyl group, and The process does not contain an aprotic polar solvent.

12. The strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof, according to claim 11.

13. ​ The process according to claim 11 or 12, wherein the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, and any combination thereof.

14. The process according to claim 11 or 12, wherein the mixture comprises at least about 10 wt% of the carboxylic acid.

15. The process according to claim 11 or 12, wherein the mixture is heated to a temperature of about 80 °C to about 160 °C.

16. A process for preparing polybenzimidazole, the process comprising heating a mixture comprising diphenyl isophthalate and 3,3',4,4'-tetraaminodiphenyl, a strong acid, a carboxylic acid, and a high-temperature stable phase transfer catalyst, wherein the process does not include an aprotic polar solvent.

17. The process according to claim 16, wherein the strong acid is selected from the group consisting of sulfuric acid, hydrochloric acid, nitric acid, methanesulfonic acid, sulfamic acid, p-toluenesulfonic acid, hydrobromic acid, and any combination thereof.

18. The process according to claim 16 or 17, wherein the carboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, oxalic acid, malic acid, citric acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, and any combination thereof.

19. The process according to claim 16 or 17, wherein the mixture comprises at least about 10 wt% of the carboxylic acid.

20. A method for suppressing corrosion, the method comprising adding the composition according to claim 1 or 2 to an industrial water system containing a metal surface.

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