JP2003034677A - Corrosion inhibitor for metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new corrosion inhibitor for metal which is expected to be easily subjected to degradation. SOLUTION: Mercaptoester carboxylic acid (salt) of the general formula (1) having an ester bond, and a corrosion inhibitor for metal containing the same are provided. A polyamine salt of mercaptoester carboxylic acid such as dodecenylsuccinic acid mono mercaptoethyl, and mercaptoester carboxylic acid (salt)-polyamine (salt) mixture may be also used as high performance corrosion inhibitor for metal. The general formula (1) is HS(Cn Hm ) OCO}z CIHj (COOM)k , (wherein, Cn Hm and CIHj are a hydrocarbon chain, n is an integer of 1-12, m is an integer of 2-2n, I is an integer of 8=25, j is an integer of 0-2I+1-k-z, k is an integer of 1-5, z is an integer of 1-5, M is H, metal or ammonium class, i.e., NH4 or ammonium originated from amine).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the use of mercaptoester carboxylic acid as a metal corrosion inhibitor.

[0002]

2. Description of the Related Art Corrosion of metals often causes important problems in the maintenance of facilities and equipment. As a countermeasure, various metal corrosion inhibitors such as chromates and phosphates and organic substances such as alkylamines and alkylammoniums are applied and effective depending on the purpose and situation.

[0003]

There are a closed system and an open system as the usage form of the metal corrosion inhibitor, but the use in the open system is particularly important because it is directly related to environmental protection. Even in the case of a closed system, waste is eventually generated during the life cycle of the applied medium and equipment. Therefore, a metal corrosion inhibitor having the properties of low toxicity and low environmental load is important in both closed and open systems.

From such a viewpoint, it is difficult to say that chromic acids, phosphates, alkylamines, alkylammoniums and the like, which are often used as metal corrosion inhibitors, are good in terms of environmental protection and waste disposal. There is a property.
For example, chromic acids are problematic in terms of safety, and phosphates are problematic in terms of eutrophication of the aquatic environment. The problems found in chromic acids and phosphates originate from the metabolic properties of the elements that make up the compound, chromium and phosphorus, and are considered to be difficult to solve.

Organic metal corrosion inhibitors have also been used. Some of the alkylamines and alkylammoniums have high performance, and it is advantageous that there is no problem with the constituent element itself, which is a problem with inorganic metal corrosion inhibitors, but many are highly toxic. . From the viewpoint of low toxicity, fatty acids corresponding to alkylamines and alkylammoniums are advantageous, but the metal corrosion inhibiting action is not strong. The development of a metal corrosion inhibitor that combines the properties of a green chemical, such as low toxicity, low accumulation, and easy decomposability, and high performance, is an issue that is extremely compatible with industrial requirements.

[0006]

[Means for Solving the Problems] It is thought that the above problems can be addressed if the molecular structure of the fatty acid (salt) is modified to enhance the metal corrosion inhibitory action and a partial structure that is easily decomposed can be introduced into the molecular structure. Was given. Based on this idea, attention was paid to aliphatic or aromatic carboxylic acids, and as a result of examining the molecular structure, a mercaptoester carboxylic acid (salt) was found. The mercaptoester carboxylic acid used in the present invention means a compound having a mercapto group, an ester bond and a carboxyl group as constituents of the molecular structure, which will be described in detail later. The mercaptoester carboxylic acid (salt) of the present invention is expected to have low toxicity because it is a carboxylic acid as a whole molecule. Not only that, ester-degrading enzymes (esterases) that are present in acids, alkalis, animals and plants, fungi, bacteria, etc. due to the presence of ester bonds
It is expected to be easily decomposed by the class.

Further, the present inventor has investigated a method of enhancing the effect of mercaptoester carboxylic acid (salt), and found out use of polyamine in the method. Polyethyleneimine is one of the polyamines, but since it functions effectively as a metal corrosion inhibitor in a metal acid washing bath (JP-A-10-140379), the present inventor investigated its action in more detail. As a result, they have found that, in at least a neutral to weakly acidic aqueous solution, the combined use of mercaptoester carboxylic acid (salt) and polyethyleneimine significantly increases the metal corrosion inhibition effect, not a simple sum of the two. It was difficult to predict the synergistic effect between polyamines such as polyethyleneimine and mercaptoester carboxylic acids (salts) from the conventional knowledge.

The present invention provides a mercaptoester carboxylic acid (salt) useful as a metal corrosion inhibitor. Further, the present invention provides a polyamine salt of a mercaptoester carboxylic acid or a mixture of a mercaptoester carboxylic acid (salt) and a polyamine (salt), which are more effective in preventing metal corrosion than the corresponding mercaptoester carboxylic acid. high. That is, the present invention relates to the following matters. [1] Mercaptoester carboxylic acid (salt) represented by the following structural formula (1)

[0009]

[Chemical 5]

(However, in the structural formula (1), C _n H _m , C _I H _j
Means a hydrocarbon chain, n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, I is an integer of 8 or more and 25 or less, j is 0 or more and 2I
+ 1-k-z or less integer, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, M means hydrogen or a metal or ammonium, that is, NH ₄ or ammonium derived from amine). [2] Mercaptoester carboxylic acid (salt) represented by the following structural formula (2)

[0011]

[Chemical 6]

(However, in the structural formula (2), C _n H _m , C _i H _j
Means a hydrocarbon chain, n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, i is an integer of 2 or more and 25 or less, j is 0 or more and 2i
+ 1-k-z or less integer, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, M is hydrogen or metal or ammonium, that is, NH ₄ or ammonium derived from amine. A metal corrosion inhibitor containing a mercaptoester carboxylic acid (salt). [3] A salt obtained by mixing a polyamine (salt) and a mercaptoester carboxylic acid (salt) represented by the following structural formula (2) or / and a mixture of both:

[0013]

[Chemical 7]

(However, in the structural formula (2), C _n H _m , C _i H _j
Means a hydrocarbon chain, n is an integer from 1 to 12 and m is 2
An integer of 2n or more, i is an integer of 2 or more and 25 or less, j is 0 or more 2
i + 1-k-z or less integer, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, M is hydrogen or a metal or ammonium, that is, NH ₄ or ammonium derived from an amine). [2] A polyamine salt of a mercaptoester carboxylic acid represented by the following structural formula (3):

[0015]

[Chemical 8]

(However, in the structural formula (3), C_nH_m , C_iH_j
 Means a hydrocarbon chain, n is an integer from 1 to 12 and m is 2
An integer of 2n or more, i is an integer of 2 or more and 25 or less, j is 0 or more 2
i + 1-k-z or less integer, k is 1 or more and 5 or less, z is 1 or more
Is an integer less than or equal to the top 5, and R− (C _tH_uN_v)_w-R 'is polyami
Means t is an integer from 2 to 10 and u is from 5 to 25
V is an integer from 1 to 5 and w is 2 or less
Is an integer not less than 200,000 and R and R'are independently hydrogen
Child or amino group or carbonization of 1 to 20 carbon atoms
It is a hydrogen group, and s is a number of 1 or more and w + 2 or less). [5] The salt and / or mixture according to [3], [4]
A metal corrosion inhibitor composition comprising the described salt.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The substances of the present invention and the substances used in the present invention will be described.

The molecular structure of the mercaptoester carboxylic acid (salt) of the present invention is generally represented by the following structural formula (1).
Indicated by.

[0019]

[Chemical 9]

In the structural formula (1), C _n H _m and C _I H _j mean a hydrocarbon chain, n is an integer of 1 or more, and m is 2 or more and 2n.
The following integer, I is preferably an integer of 8 or more and usually an integer of 25 or less, j is an integer of 0 or more and 2I + 1-k-z or less, k is an integer of 1 or more and 5 or less, and z is 1 or more. Integer less than or equal to 5, M
Means a hydrogen atom or a metal atom or ammoniums, that is, NH ₄ or ammonium derived from an amine. As a preferable condition for n and I, n is an integer of 1 or more and 12 or less, and I is an integer of 8 or more and 25 or less. Of these numerical ranges, the upper limit of 12 carbon atoms and the upper limit of I carbon atoms
25, k and z are the result of considering the advantages of industrial synthesis. Therefore, it is possible to exceed these upper limits for n, I, k, and z.

The reason why the number of carbon atoms I is particularly 8 or more is that it is novel as a substance and its performance as a metal corrosion inhibitor. Regarding the performance, for example, when applied to Mg, Al, Zn, etc., the one with a relatively large number of carbon atoms tends to be more effective, and as a guideline, the number of carbon atoms I tends to be 8 or more. It is due to the fact.

In the above structural formula (1), k can be described as an integer of 1 or more, and z can be described as an integer of 1 or more.
Is 3 or less, z is preferably 3 or less,
As a concrete combination, k = 1, z = 1, k = 2, z = 1
Or k = 3, z = 1 or k = 1, z = 2 or k = 2, z = 2 or k = 3, z
= 2, k = 1, z = 3, k = 2, z = 3, k = 3, z = 3, etc. More preferably, k = 1 and z = 1, and the molecular structure is represented by the following structural formula (4).

[0023]

[Chemical 10]

It is represented by

Further, HS (C _n H _m ) OCO C _I H _j (COOM) _{2 and the} like are preferable, but k = 2 and z = 1.

The mercaptoester carboxylic acids (salts) represented by the structural formulas (1) and (4) are useful as high-performance metal corrosion inhibitors, but are hydrophilic when protecting metals in contact with water. It is also conceivable to add a sexing agent at a high eye concentration and use it. In this case, agents exceeding the lower limit of the number of carbon atoms I shown in the explanation of structural formula (1) or structural formula (4) can be used. Therefore, the general formula of the mercaptoester carboxylic acid (salt) that can be used as the metal corrosion inhibitor of the present invention can be represented by the structural formula (2).

[0027]

[Chemical 11]

In the structural formula (2), C _n H _m and C _i H _j are hydrocarbon chains, n is an integer of 1 to 12 and m is 2 to 2n.
The following integers, i is an integer from 2 to 25, j is 0 to 2i + 1
-K-z an integer, k is 1 to 5 integer, z is 1 to 5 integer, M denotes an ammonium from hydrogen or a metal or ammonium compound i.e. NH ₄ or amine. However, these numerical ranges are based on the results considering the advantages of industrial synthesis. Therefore, the number of carbon atoms i
Can be 0 or 1, and can exceed the upper limit 12 of the number of carbon atoms n 12, the upper limit 25 of the number of carbon atoms i, the upper limit 5 of k, or the upper limit 5 of z.

The formal difference between the structural formulas (1) and (2) is the number of carbon atoms in the carboxylic acid residue. Those having a relatively large number of carbon atoms in the carboxylic acid residue were better as metal corrosion inhibitors, but those compounds were also novel compounds. In consideration of this point, in order to distinguish and show the general structural formulas of compounds, the hydrocarbon chain in the carboxylic acid residue of structural formula (1) is defined as C _I H _j , and The hydrocarbon chain of was represented as C _i H _j . Since the compound group represented by Structural Formula (4) is a part of the compound group represented by Structural Formula (1), the hydrocarbon chain in the carboxylic acid residue is shown as C _I H _j .

These mercaptoester carboxylic acids (salts) are composed of a mercapto alcohol residue and a carboxylic acid residue in terms of molecular structure. In the present specification, the characteristics of the mercaptoester carboxylic acid (salt) represented by the structural formula (1) or the structural formula (2) will be described separately for the mercapto alcohol residue and the carboxylic acid residue. This description also applies to Structural Formula (3) and Structural Formula (4).

Mercapto alcohol residue HS (C _n H _m ) O
In the case of, the minimum value of the number of carbon atoms n should be possible up to 1, but the preferred minimum value of the number of carbon atoms n is 2 in terms of synthetic technology.
Becomes The upper limit of the maximum value of the number of carbon atoms n is considered to be gradual, but practically it is considered to be about 12, preferably about 8. These upper limits are given as a guide in consideration of the reason for synthesis, and can exceed the range shown here. The number m of hydrogen atoms corresponds to the number n of carbon atoms, and the minimum value is 2 and the maximum value is 2 n. Summarizing the consideration of the range shown here, the range of the number of carbon atoms n can be 1 or more, but 2 or more and 12 or less is practical, preferably 2 or more and 8 or less, and more preferably
It is 2 or more and 6 or less.

Specific examples of the hydrocarbon chain --C _n H _m --include ethylene chains, propylene chains, butene chains, pentene chains, hexene chains, etc., and aliphatic hydrocarbons represented by-(CH ₂ ) _y- (y = n). hydrogen chain, o- phenylene chain, m- phenylene chain, or a phenylene chain such as p- phenylene chain _{-C 6 H 3 (CH 3)} -, -C 6 H 4 CH
_{2 -, - CH 2 C 6} H 4 CH 2 - hydrocarbon chain having an aromatic ring such as may be exemplified. Of these, ethylene chains, propylene chains, phenylene chains and the like are preferable, and ethylene chains are particularly preferable. Specific examples of the mercapto alcohol residue include a mercaptoethanol residue, a mercaptopropanol residue, a mercaptobutanol residue, a mercaptopentanol residue, a mercaptohexanol residue, a mercaptocyclopentanol residue, a mercaptocyclohexanol residue, and a mercaptopropane. Non-alicyclic or alicyclic aliphatic mercapto alcohol residues such as diol residues and aromatic mercapto alcohol residues such as mercaptophenol residues are preferred choices. Among these, mercaptoethanol residues, mercaptopropanol residues, mercaptopropanediol residues, mercaptophenol residues and the like are more preferable examples.

The number I of carbon atoms in the carboxylic acid residue {--CO} _z C _I H _j (COOM) _k of the structural formulas (1) and (4) is suitably 8 or more. Although the upper limit of the number of carbon atoms I is considered to be gradual, it is practically about 30, preferably 25, more preferably about 20. These upper limits are given as a guide in consideration of the reason for synthesis, and the number of carbon atoms shown here may be exceeded if the raw materials for synthesis are easily available.

The number j of hydrogen atoms corresponding to the number I of carbon atoms
, The minimum value is 0, and the maximum value is in the case of structural formula (1) (2I
+ 2-z-k) and 2I in the case of the structural formula (4).

Carboxylic acid residue of structural formula (2) {--CO} _z
It is possible that C _i H _j (COOM) _{k having} a carbon atom number i of 0 or more can be used, but the preferable lower limit of the carbon atom number i is considered to be about 2. The upper limit of the number of carbon atoms i is considered to be gradual, but practically it is about 30, preferably 2
5, and more preferably about 20. These upper limits are given as a guide in consideration of the reason for synthesis, and the number of carbon atoms shown here may be exceeded if the raw materials for synthesis are easily available.

The number of hydrogen atoms j corresponding to the number of carbon atoms i
, The minimum value is 0, and the maximum value is structural formula (2) (2i + 2
-Z-k).

Hydrocarbon chain C _I H _j corresponding to k = 1 and z = 1
Specific examples of the octene chain, nonene chain, decene chain, undecene chain, dodecene chain and the like aliphatic hydrocarbon chain represented by-(CH ₂ ) _I- , cyclooctene chain, cyclononene chain,
Cyclodecene chain, cycloundecene chain, cyclododecene chain, etc .- (C _I H _2I-2 ) -A cycloaliphatic hydrocarbon chain having a cyclic structure represented by-, or naphthalene chain -C ₁₀ H ₆ -or -C ₆ H ₂ (CH ₃ ) ₂ −, −C ₆ H (CH ₃ ) ₃ −, −C ₆ (CH ₃ ) ₄ −, −C ₆ H ₃ (C ₂ H ₅ ) −, −C ₆ H ₂ (C ₂ H ₅ ) ₂₋ , −C ₆ H (C ₂ H ₅ ) ₃ −, −C ₆ (C ₂ H ₅ ) ₄ −, −C ₆ H ₃ (C ₃ H ₇ ) −, −C ₆ H ₂ (C ₃ H ₇ ) ₂ −, −C ₆ H (C ₃ H ₇ ) ₃ −, −C ₆ (C ₃ H ₇ ) ₄ −, −CH ₂ CH ₂ C ₆ H ₄ −, −CH ₂ C ₆ H _{4 CH 2 -, -CH 2 CH 2} C 6 H 4 -, -CH 2 CH 2 CH 2 C 6 H 4 -, -CH 2 CH 2 C 6 H 4 CH 2 - is a hydrocarbon chain having an aromatic ring such as It can be illustrated. As a partial structure of these hydrocarbon chains C _I H _j , for example, --CH ₂ CH (CH ₃ )-, --CH (CH ₃ ) CH (CH ₃ )-, and further --CH ₂ CHR ^x- (R ^x is a carbon atom A hydrogen atom) can have a branched structure. Further, an unsaturated bond such as a double bond may be present, and for example, -CH ₂ CH (CH ₂ CH = CHC ₉ H ₁₉ )-, -CH ₂ CH (C ₁₂ H ₂₃ )-(C ₁₂ H ₂₃ can be present in various positions such as a dodecenyl group).

Specific examples of the hydrocarbon chain C _i H _j corresponding to k = 1 and z = 1 include the specific examples of the hydrocarbon chain C _I H _j corresponding to k = 1 and z = 1 described above. in addition, methylene chain, ethylene chain, a propylene chain, butene chain, pentene-chain, hexene chain, heptene chain, such as - (CH _{2) i} - aliphatic or hydrocarbon chain represented by, cyclobutene chain, cyclopentene chain, cyclohexene chain and cycloheptene chain _{- (C i H 2i-2} ) - or cycloaliphatic hydrocarbon chain having a cyclic structure represented by a phenylene chain -C ₆ H ₄ - hydrocarbon chain having an aromatic ring, and others. These hydrocarbon chain moiety as for example _{-CH 2 CH (CH 3) -} , - CH (CH 3) CH (CH 3) -, more -CH ₂ CHR ^x - of (R ^x represents a hydrocarbon group) It is possible for there to be a branched structure. May be present more unsaturated bonds such as double bonds, for example, dihydro-phenylene chain -C ₆ H ₆ -, tetrahydropyran-phenylene chain -C ₆ H ₈ - and other -CH = CH-, -CH = CH _{-CH 2 -, -CH = C (} CH 3) -, -CH 2 C (= CH 2) -, it can exist in a variety of locations as. Hydrocarbon chain C _I H _j corresponding to k = 2 and z = 1 or to k = 1 and z = 2
And C _i H _j are equivalent to those in which one hydrogen atom has been removed from the hydrocarbon chain corresponding to k = 1 and z = 1 to form a bond. For example, -C ₈ H ₁₅ is a linear aliphatic saturated hydrocarbon chain _{C I H j <, - C} 9 H 17 <, - C 10 H 19 <, - C 11 H 21 <, - C
₁₂ H ₂₃ <and the like can be exemplified. As the linear aliphatic saturated hydrocarbon chain C _i H _j , in addition to the example of the linear aliphatic saturated hydrocarbon chain C _I H _j , —CH <, —C ₂ H _{3 <, - C 3 H 5 <} , - C 4 H 7 <, - C 5 H 9 <,
_{-C 6 H 11 <, - C} 7 H 13 < others. -C ₈ H ₁₃ is a saturated aliphatic hydrocarbon chain C _I H _j having a straight-chain aliphatic unsaturated hydrocarbon chain C _I H _j or cyclic structure _{<, - C 9 H 15 <} , - C 10 H 17 < , -C ₁₁ H ₁₉ <, -C
₁₂ H ₂₁ <, etc. can be exemplified. Examples of the aliphatic saturated hydrocarbon chain C _i H _j having a straight-chain aliphatic unsaturated hydrocarbon chain C _i H _j or cyclic structures, fats having a straight-chain aliphatic unsaturated hydrocarbon chain C _I H _j or cyclic structure family saturated hydrocarbon chain C _I H _j -C ₂ in addition to the examples of _{H <, - C 3 H 3} <, - C 4 H 5 <, - C 5 H 7 <, - C 6 H 9 <,
-C ₇ H ₁₁ <others. The aromatic hydrocarbon chain C _I H _j has a benzene ring such as -C ₆ H (CH ₃ ) ₂ <, -C ₆ H ₂ (C ₂ H ₅ ) <, or a naphthalene ring such as -C ₁₀ H ₅ <. And the like can be exemplified. As the aromatic hydrocarbon chain C _i H _j , in addition to the example of the aromatic hydrocarbon chain C _I H _j , -C ₆ H ₃ <, -C ₆ H ₂ (CH ₃ ) <and the like are also possible.

The hydrocarbon chain C _I H _j corresponding to k = 2 and z = 2
C _i H _j is a hydrogen atom from the hydrocarbon chain corresponding to k = 1 and z = 1.
Equivalent to the two that came off and became a bond. For example,
As the straight-chain aliphatic saturated hydrocarbon chain C _I H _j ,> C ₈ H ₁₄ <,> C ₉ H ₁₆ <,> C ₁₀ H ₁₈ <,> C ₁₁ H ₂₀ <,> C
_In addition to the examples of the straight-chain aliphatic saturated hydrocarbon chain C _I H _j as the straight-chain aliphatic saturated hydrocarbon chain C _i H _j such as ₁₂ H ₂₂ <> C <,> C ₂ H ₂ <,> C ₃ H ₄ <,> C ₄ H ₆ <,> C ₅ H ₈ <,>
_{C 6 H 10 <,> C} 7 H 12 < There can be exemplified. Linear aliphatic unsaturated hydrocarbon chain C _I H _j or aliphatic saturated hydrocarbon chain C _I H _j having a cyclic _{structure> C 8 H 12 <,>} C 9 H 14 <,> C 10 H 16 < , ＞ C ₁₁ H ₁₈ ＜, ＞ C
₁₂ H ₂₀ <etc., the aliphatic saturated hydrocarbon chain C _i H _j having a straight-chain aliphatic unsaturated hydrocarbon chain C _i H _j or cyclic structures, aromatic straight chain fatty unsaturated hydrocarbon chain C _I H _j In addition to the example of C. or a saturated saturated hydrocarbon chain C _I H _{j having} a cyclic structure,> C ₂ <,> C ₃ H ₂ <,> C ₄ H ₄ <,> C ₅ H ₆ <,> C ₆ H ₈ <,
> C ₇ H ₁₀ <, and others. The hydrocarbon chain C _I H _j having an aromatic ring such as a benzene ring or a naphthalene ring includes> C ₆ (CH ₃ ) ₂ <,> C ₆ H (C ₂ H ₅ ) <,> C ₆ H (C ₃ H ₇ ) <,
Examples of the hydrocarbon chain C _i H _j having an aromatic ring such as benzene ring or naphthalene ring such as> C ₁₀ H ₄ <in addition to the example of the hydrocarbon chain C _I H _j having an aromatic ring:> C ₆ H ₂ <,> C ₆ H (CH ₃ ) <and the like can be exemplified. In these examples, "<"
And ">" mean two bonds.

Examples of the mercaptoester carboxylic acid residue having the hydrocarbon chain C _I H _j described above include octenyl succinic acid residue, octanyl succinic acid residue, decenyl succinic acid residue, decanyl succinic acid residue, dodecenyl succinic acid residue. , Dodecanyl succinic acid residue, octadecenyl succinic acid residue, octadecanyl succinic acid residue, maleated methylcyclohexene tetrabasic acid residue, methyl norbornene-
2,3-dicarboxylic acid residue, methylendomethylenetetrahydrophthalic acid residue, and other aliphatic dicarboxylic acid residues, aliphatic polycarboxylic acid residues, and naphthalenedicarboxylic acid residues, and other aromatic dicarboxylic acid residues, An aromatic polycarboxylic acid residue can be illustrated. Among these examples, considering the water solubility as mercaptoester carboxylic acid (salt), octenyl succinic acid residue, octanyl succinic acid residue, decenyl succinic acid residue, decanyl succinic acid residue, dodecenyl succinic acid residue, dodeca Nylsuccinic acid residues and the like are preferable, and dodecenylsuccinic acid residues, dodecanylsuccinic acid residues, octadecenylsuccinic acid residues, octadecanylsuccinic acid residues and the like are preferable from the viewpoint of fat solubility. The dodecenyl succinic acid residue and the dodecanyl succinic acid residue are water-soluble and fat-soluble.
This is because the solubility varies depending on the salt or free acid.
Further, as the mercaptoester carboxylic acid residue having a hydrocarbon chain C _i H _{j, in addition} to the mercaptoester carboxylic acid residue having a hydrocarbon chain C _I H _j exemplified above, a succinic acid residue and a maleic acid residue Residue, methylsuccinic acid residue, citraconic acid residue, itaconic acid residue, glutaric acid residue, tetrahydrophthalic acid residue, hexahydrophthalic acid residue, tetrahydromethylphthalic acid residue, cyclopentanetetracarboxylic acid residue Fats having chlorine atom or fluorine such as aliphatic dicarboxylic acid residue or aliphatic polycarboxylic acid residue such as endomethylenetetrahydrophthalic acid residue, hexahydromethylphthalic acid residue or other chlorendic acid residue Aromatic dicals such as group dicarboxylic acid residues, phthalic acid residues, trimellitic acid residues, pyromellitic acid residues, mellitic acid residues, etc. Emission acid residue or an aromatic polycarboxylic acid residue can be exemplified. Oxalic acid residues and malonic acid residues can also be used if there are no problems with the synthetic raw materials. Among these, succinic acid residue, maleic acid residue, hexahydrophthalic acid residue, phthalic acid residue, trimellitic acid residue, pyromellitic acid residue and the like are preferable examples.

Therefore, structural formula (1) and structural formula (2)
And preferred examples of the mercaptoester carboxylic acid represented by the structural formula (4) include the hydrocarbon chain C _n listed in the preceding section.
Mercaptoalcohol with H _m and hydrocarbon chain C _I H _j or
It is a combination of carboxylic acid residues (dicarboxylic acid residues, polycarboxylic acid residues) having C _i H _j .

Among the preferred specific examples of the mercaptoester carboxylic acid, a mercaptoethanol residue and a hydrocarbon chain
Among those having C _I H _j , examples in which both k and z are 1 are monomercaptoethyl octenyl succinate, monomercaptoethyl octanyl succinate, monomercaptoethyl decenyl succinate, monomercaptoethyl decanyl succinate, monomercapto dodecenyl succinate. Ethyl, monomercaptoethyl dodecyl succinate, monomercaptoethyl pentadecenyl succinate, monomercaptoethyl pentadecenyl succinate, monomercaptoethyl octadecenyl succinate, monomercaptoethyl octadecenyl succinate, methyl norbornene -Monomercaptoethyl 2,3-dicarboxylate, monomercaptoethyl aliphatic dicarboxylate such as methylendomethylene tetrahydrophthalate monomercaptoethyl, and naphthalenedicarboxylate monomercapto Aromatic dicarboxylic acid mono-mercaptoethyl such as ethyl can be exemplified.

Monomercaptoethyl aliphatic polycarboxylate and bismercaptoethyl aliphatic polycarboxylate,
There are k and z such as aromatic polycarboxylic acid monomercaptoethyl and aromatic polycarboxylic acid bismercaptoethyl.
Those other than 1 can be synthesized. For example, maleated methylcyclohexene tetrabasic acid monomercaptoethyl or maleated methylcyclohexene tetrabasic acid bismercaptoethyl having a maleated methylcyclohexene tetrabasic acid residue can be industrially synthesized.

Examples of the mercaptoester carboxylic acid having a hydrocarbon chain C _i H _j include, in addition to the mercaptoester carboxylic acid having a hydrocarbon chain C _I H _j exemplified above, monomercaptoethyl succinate and monomercapto maleate. Ethyl, Monomercaptoethyl methylsuccinate, Monomercaptoethyl citracone, Monomercaptoethyl itaconate, Monomercaptoethyl glutarate, Monomercaptoethyl tetrahydrophthalate, Monomercaptoethyl hexahydrophthalate, Monomercaptoethyl tetrahydromethylphthalate, Cyclo Bismercaptoethyl pentanetetracarboxylate, Monomercaptoethyl endomethylenetetrahydrophthalate, Monomercaptoethyl aliphatic dicarboxylate such as hexahydromethylphthalate monomercaptoethyl Aliphatic dicarboxylic acid mono-mercaptoethyl with such as chlorine atom and fluorine, such as other chlorendic acid mono-mercaptoethyl, aromatic dicarboxylic acid mono-mercaptoethyl such as phthalic acid mono-mercaptoethyl can be exemplified. Monomercaptoethyl oxalate and monomercaptoethyl malonate are also possible if there are no problems with the synthetic raw materials. Among these, monomercaptoethyl succinate, monomercaptoethyl maleate, monomercaptoethyl hexahydrophthalate, and monomercaptoethyl phthalate are preferred examples.

Monomercaptoethyl aliphatic polycarboxylate and bismercaptoethyl aliphatic polycarboxylate,
There are k and z such as aromatic polycarboxylic acid monomercaptoethyl and aromatic polycarboxylic acid bismercaptoethyl.
Those other than 1 can be synthesized. For example, trimeric acid monomercaptoethyl having trimellitic acid residue,
Cyclopentanetetracarboxylic acid monomercaptoethyl or cyclopentanetetracarboxylic acid bismercaptoethyl having cyclopentanetetracarboxylic acid residue having one or two cysteamine residues, and pyromellitic acid having pyromellitic acid residue Examples include monomercaptoethyl, bismercaptoethyl pyromellitic acid, monomercaptoethyl melitate, bismercaptoethyl melitate, and trismercaptoethyl melitate. Of these, preferred examples are trimeric acid monomercaptoethyl, pyromellitic acid monomercaptoethyl, and pyromellitic acid bismercaptoethyl.

Among the preferred specific examples of the mercaptoester carboxylic acid having a mercaptopropanol residue and a hydrocarbon chain C _I H _j , examples in which both k and z are 1 are monomercaptopropyl octenyl succinate and octanyl. Monomercaptopropyl succinate, Monomercaptopropyl decenyl succinate, Monomercaptopropyl decanyl succinate, Monomercaptopropyl dodecenyl succinate, Monomercaptopropyl dodecyl succinate, Monomercaptopropyl pentadecenyl succinate,
Monomercaptopropyl pentadecanyl succinate, Monomercaptopropyl octadecenyl succinate, Monomercaptopropyl octadecanyl succinate, Monomercaptopropyl methylnorbornene-2,3-dicarboxylate, Monomermethylene tetrahydrophthalate monomercaptopropyl Examples thereof include aromatic dicarboxylic acid monomercaptopropyl such as aliphatic dicarboxylic acid monomercaptopropyl and naphthalene dicarboxylic acid monomercaptopropyl.

Aliphatic polycarboxylic acid monomercaptopropyl, aliphatic polycarboxylic acid bismercaptopropyl, etc., or aromatic polycarboxylic acid monomercaptopropyl, aromatic polycarboxylic acid bismercaptopropyl, etc. Things can also be synthesized. For example, maleated methylcyclohexene tetrabasic acid monomercaptopropyl or maleated methylcyclohexene tetrabasic acid bismercaptopropyl having a maleated methylcyclohexene tetrabasic acid residue can be industrially synthesized.

Examples of the mercaptoester carboxylic acid having a hydrocarbon chain C _i H _j include, in addition to the mercaptoester carboxylic acid having a hydrocarbon chain C _I H _j exemplified above, monomercaptopropyl succinate and monomercapto maleate. Propyl, Monomercaptopropyl methylsuccinate, Monomercaptopropyl citraconate, Monomercaptopropyl itaconic acid, Monomercaptopropyl glutarate, Monomercaptopropyl tetrahydrophthalate, Monomercaptopropyl hexahydrophthalate, Monomercaptopropyl tetrahydromethylphthalate, Cyclo Aliphatic dicals such as pentanetetracarboxylic acid bismercaptopropyl, endomethylenetetrahydrophthalic acid monomercaptopropyl, and hexahydromethylphthalic acid monomercaptopropyl Phosphate mono-mercaptopropyl aliphatic dicarboxylic acid mono-mercaptopropyl with such as chlorine atom and fluorine, such as other chlorendic acid mono-mercaptopropyl, aromatic dicarboxylic acid mono-mercaptopropyl such as phthalic acid mono-mercaptopropyl can be exemplified. Monomercaptopropyl oxalate and monomercaptopropyl malonate are also possible if there are no problems with the synthetic raw materials. Among these, monomercaptopropyl succinate, monomercaptopropyl maleate, monomercaptopropyl hexahydrophthalate, and monomercaptopropyl phthalate are preferred examples.

Aliphatic polycarboxylic acid monomercaptopropyl, aliphatic polycarboxylic acid bismercaptopropyl, etc., or aromatic polycarboxylic acid monomercaptopropyl, aromatic polycarboxylic acid bismercaptopropyl, etc. Things can also be synthesized. For example, monomercaptopropyl trimellitate having a trimellitic acid residue, or as a monomer having one or two cysteamine residues, cyclopentanetetracarboxylic acid monomercaptopropyl or cyclopentanetetracarboxylic acid having a cyclopentanetetracarboxylic acid residue. Examples include bismercaptopropyl carboxylate, monomercaptopropyl pyromellitic acid having a pyromellitic acid residue, bismercaptopropyl pyromellitic acid, monomercaptopropyl melitate, bismercaptopropyl melitate, and trismercaptopropyl melitate. Of these, preferred examples are trimeric acid monomercaptopropyl, pyromellitic acid monomercaptopropyl, and pyromellitic acid bismercaptopropyl.

Among the preferred specific examples of the mercaptoester carboxylic acid, a mercaptophenol residue and a hydrocarbon chain
Among those having C _I H _j , examples in which both k and z are 1 are octenyl succinate monomercaptophenyl, octanyl succinate monomercaptophenyl, decenyl succinate monomercaptophenyl, decanyl succinate monomercaptophenyl, dodecenyl succinate monomercapto. Phenyl, Monomercaptophenyl dodecanyl succinate,
Monomercaptophenyl pentadecenyl succinate, Monomercaptophenyl pentadecenyl succinate, Monomercaptophenyl octadecenyl succinate, Monomercaptophenyl octadecenyl succinate, Monomercaptophenyl methylnorbornene-2,3-dicarboxylate And aliphatic dicarboxylic acid monomercaptophenyl such as methylendomethylene tetrahydrophthalate monomercaptophenyl and aromatic dicarboxylic acid monomercaptophenyl such as naphthalene dicarboxylic acid monomercaptophenyl.

Aliphatic polycarboxylic acid monomercaptophenyl, aliphatic polycarboxylic acid bismercaptophenyl, etc., or aromatic polycarboxylic acid monomercaptophenyl, aromatic polycarboxylic acid bismercaptophenyl, etc. Things can also be synthesized. For example, maleated methylcyclohexene tetrabasic acid monomercaptophenyl or maleated methylcyclohexene tetrabasic acid bismercaptophenyl having a maleated methylcyclohexene tetrabasic acid residue can be industrially synthesized.

Examples of the mercaptoester carboxylic acid having a hydrocarbon chain C _i H _j include, in addition to the mercaptoester carboxylic acid having a hydrocarbon chain C _I H _j as exemplified above, monomercaptophenyl succinate and monomercapto maleate. Phenyl, Monomercaptophenyl methylsuccinate, Monomercaptophenyl citraconate, Monomercaptophenyl itaconic acid, Monomercaptophenyl glutarate, Monomercaptophenyl tetrahydrophthalate, Monomercaptophenyl hexahydrophthalate, Monomercaptophenyl tetrahydromethylphthalate, Cyclo Aliphatic dicals such as bismercaptophenyl pentanetetracarboxylic acid, monomercaptophenyl endomethylenetetrahydrophthalate, and monomercaptophenyl hexahydromethylphthalate Aliphatic dicarboxylic acid mono-mercaptophenyl with such as chlorine atom and fluorine, such as phosphate mono-mercaptophenylboronic other chlorendic acid mono-mercaptophenyl, aromatic dicarboxylic acid mono-mercaptophenyl such as phthalic acid mono-mercaptophenyl can be exemplified. Monomercaptophenyl oxalate and monomercaptophenyl malonate are also possible if there are no problems with the synthetic raw materials. Among these, monomercaptophenyl succinate, monomercaptophenyl maleate, monomercaptophenyl hexahydrophthalate, and monomercaptophenyl phthalate are preferred examples.

Aliphatic polycarboxylic acid monomercaptophenyl, aliphatic polycarboxylic acid bismercaptophenyl, etc., or aromatic polycarboxylic acid monomercaptophenyl, aromatic polycarboxylic acid bismercaptophenyl, etc. Things can also be synthesized. For example, monomercaptophenyl trimellitate having a trimellitic acid residue, or as a monomer having one or two cysteamine residues, cyclopentanetetracarboxylic acid monomercaptophenyl or cyclopentanetetracarboxylic acid having a cyclopentanetetracarboxylic acid residue. Examples thereof include bismercaptophenyl carboxylate, monomercaptophenyl pyromellitic acid having a pyromellitic acid residue, bismercaptophenyl pyromellitic acid, monomercaptophenyl melitate, bismercaptophenyl melitate, and trismercaptophenyl melitate. Of these, monomercaptophenyl trimellitate, monomercaptophenyl pyromelliticate, and bismercaptophenyl pyromelliticate are preferred examples. The mercaptoester carboxylic acid (salt) of the present invention or the mercaptoester carboxylic acid (salt) used in the present invention has been described above.

Among the compounds represented by Structural Formula (1) or Structural Formula (4), the more preferable ones are water-soluble or water-dispersible monomercaptoethyl octenyl succinate, monomercaptopropyl octenyl succinate, and octenyl succinic acid. Monomercaptophenyl, octamer succinate monomercaptoethyl, octanyl succinate monomercaptopropyl, octanyl succinate monomercaptophenyl, decenyl succinate monomercaptopropyl, decenyl succinate monomercaptopropyl,
Monomercaptophenyl decenyl succinate, Monomercaptoethyl decanyl succinate, Monomercaptopropyl decanyl succinate, Monomercaptophenyl decanyl succinate, Monomercaptoethyl dodecenyl succinate, Monomercaptophenyl dodecenyl succinate, Monomercapto phenyl succinate, Dodecenyl succinate Monomercaptopropyl dodecanyl succinate and monomercaptophenyl dodecanyl succinate are preferred. In particular, Li salts of the mercaptoester carboxylic acids exemplified here and metal salts such as Na and K salts are preferable in terms of water solubility or water dispersibility.
The free acid form is also preferred when it can be expected that the acid will be neutralized in the water system to which it is applied. It should be noted that the examples shown here are considered to be relatively advantageous, and depending on the purpose, depending on the purpose, monodecadecyl succinate monomercaptoethyl, pentadecenyl succinic acid monomercaptopropyl, pentadecese succinate. Monomercaptophenyl nylsuccinate,
Monomercaptoethyl pentadecanyl succinate, Monomercaptopropyl pentadecanyl succinate, Monomercaptophenyl pentadecanyl succinate, Monomercaptoethyl octadecenyl succinate, Monomercaptopropyl octadecenyl succinate, Octadecese Monomercaptophenyl nirsuccinate, monomercaptoethyl octadecanyl succinate, monomercaptopropyl octadecanyl succinate, monomercaptophenyl octadecanyl succinate and the like can be dissolved or dispersed in water and used.

From the viewpoint of fat solubility, monomercaptoethyl dodecenyl succinate, monomercaptopropyl dodecenyl succinate, monomercaptophenyl dodecenyl succinate, monomercaptoethyl dodecanyl succinate, monomercaptophenyl dodecyl succinate, monomercaptophenyl dodecyl succinate, Monomercaptoethyl pentadecenyl succinate, Monomercaptopropyl pentadecenyl succinate, Monomercaptophenyl pentadecenyl succinate, Monomercaptoethyl pentadecanyl succinate, Monomercaptopropyl pentadecenyl succinate, Pentadeca Monomercaptophenyl nylsuccinate,
Monomercaptoethyl octadecenyl succinate, Monomercaptopropyl octadecenyl succinate, Monomercaptophenyl octadecenyl succinate, Monomercaptoethyl octadecanyl succinate, Monomercaptopropyl octadecenyl succinate, Octadeca Monomercaptophenyl nylsuccinate, etc. are preferred. The examples shown here are considered to be relatively advantageous, and depending on the purpose, monomercaptoethyl octenyl succinate, monomercaptopropyl octenyl succinate, monomercaptophenyl octenyl succinate, octanyl succinate monosuccinate. Mercaptoethyl, octamer succinate monomercaptopropyl, octanyl succinate monomercaptophenyl, decenyl succinate monomercaptoethyl, decenyl succinate monomercaptopropyl,
It is possible to use monomercaptophenyl decenyl succinate, monomercaptoethyl decanyl succinate, monomercaptopropyl decanyl succinate, and monomercaptophenyl decanyl succinate. Including those exemplified here, monomercaptoethyl alkyl succinate,
Monomercaptopropyl alkyl succinate, monomercaptophenyl alkyl succinate, monomercaptoethyl alkenyl succinate, monomercaptopropyl alkenyl succinate, monomercaptophenyl alkenyl succinate and other mercaptoester carboxylic acids are generally in the form of salts. Preferred from the viewpoint of water solubility or water dispersibility,
The free acid form is preferable in terms of fat solubility. When the application target is an aqueous system, the free acid form is also preferable if the acid is neutralized. In Structural Formula (1), Structural Formula (2), and Structural Formula (4), M means a hydrogen atom, a metal atom, or an ammonium, that is, NH ₄ or an ammonium derived from an amine. Therefore, as a special example of the mercaptoester amide carboxylate, ammonium derived from polyethyleneimine, polyallylamine or polyvinylamine is also included in the category of M. M for free mercaptoester carboxylic acid
Becomes a hydrogen atom. When using a metal atom as M, alkali metal atoms such as Li, Na, K, Rb, Cs alkaline earth metal atoms such as Be, Mg, Ca, Sr, Ba and the like or Fe, Co, Ni, depending on the purpose. Cu, Zn, Al, Sc, Y, La, Ce, P
Other metals such as lanthanoids such as r and Nd may be used.

The mercaptoester carboxylic acid (salt) which is the basis of the present invention has been described above. These mercapto ester carboxylates are preferably synthesized by first synthesizing a mercapto ester carboxylic acid and, if necessary, neutralizing with a base.

The mercaptoester carboxylic acid is a reaction of an acid anhydride of a dicarboxylic acid or a polycarboxylic acid with a mercapto alcohol, a reaction of an acid chloride of the dicarboxylic acid or a polycarboxylic acid with a mercapto alcohol, a dicarboxylic acid or a polycarboxylic acid. It can be easily synthesized by a condensation reaction of mercapto alcohol with mercapto alcohol. Although there are several options for the synthetic method, in view of industrial synthesis, it is preferable to synthesize the dicarboxylic acid or polycarboxylic acid anhydride with a mercapto alcohol. In this method, by-products of waste can be prevented by selecting reaction conditions. The reaction temperature may be selected at any temperature as long as the acid anhydride of the dicarboxylic acid or polycarboxylic acid used in the reaction reacts with the mercapto alcohol. However, if the reaction temperature is low, the reaction rate becomes slow and practical synthesis cannot be performed. When the reaction temperature is high, the generated mercaptoester carboxylic acid is likely to decompose. For these reasons, the reaction temperature is preferably selected within the range of room temperature to 160 ° C. Usually, the more preferable reaction temperature is 80 to 140 ° C, and the more preferable reaction temperature is 100 to 140 ° C.
It is about 120 ° C. The reaction temperature in the examples of the present invention is especially 110.
° C was preferred. The reaction time can be long when the reaction temperature is low and short when the reaction temperature is high. Therefore,
The reaction temperature may be determined according to the reaction temperature, and the reaction time can be arbitrarily determined unless the decomposition of the raw material or the decomposition of the product poses a problem. Usually, it is practical to adjust the reaction temperature to keep the reaction time within the range of 0.1 to 6 hours, considering the synthesis rate, it is preferably 0.3 to 4 hours, more preferably 0.5 to 3 hours. Is.

When an acid anhydride of a dicarboxylic acid or a polycarboxylic acid is reacted with a mercapto alcohol, the partial structure of the acid anhydride (-CO-O-CO-) and the hydroxyl group (-OH) of the mercapto alcohol are in a molar ratio. As a general rule, they should be mixed and reacted so that the ratio becomes 1: 1. However, in the actual synthetic operation, the molar ratio of (-CO-O-CO-) to (-OH) can be changed within the range of, for example, 10: 1 to 1:10. That is, when it is used as a metal corrosion inhibitor, other components may be blended, so that there is no problem even if unreacted raw materials remain. However,
Usually, it is practical to keep the molar ratio of (-CO-O-CO-) and (-OH) to about 3: 1 to 1: 3 even if it is wide,
Preferably 2: 1 to 1: 2, more preferably 1.5: 1 to 1: 1.5
Alternatively, it is safe to select within the range of 1.2: 1 to 1: 1.2. The purity of the acid anhydride or mercapto alcohol of dicarboxylic acid or polycarboxylic acid used in the reaction is not always
Not 100%. Therefore, practically, (-CO-O-CO
It is particularly preferable to select the molar ratio of-) and (-OH) in the range of 1.1: 1 to 1: 1.1.

Acid anhydrides of dicarboxylic acids or polycarboxylic acids and mercapto alcohols can be reacted without a solvent, which is preferable, but a solvent may be used. Examples of the solvent include hydrocarbons such as hexane, cyclohexane, heptane, octane, benzene, toluene and xylene, and acid anhydrides of dicarboxylic acids or polycarboxylic acids such as ethers such as diisopropyl ether, dibutyl ether and dioxane, and mercapto alcohols. Any substance that does not substantially react with can be used. Further, kerosene, light oil, heavy oil and the like can be used as a reaction solvent.

The reaction is preferably carried out under vacuum or in an atmosphere of an inert gas which does not oxidize, such as nitrogen, helium, neon, argon or carbon dioxide. However,
Depending on the circumstances, the reaction can be carried out in air.

In the present invention, a polyamine salt of mercaptoester carboxylic acid or a mercaptoester carboxylic acid (salt) -polyamine (salt) mixture can also be used, and these will be described below.

In the present invention, various polyamines which are “organic compounds having two or more amino groups” can be used. Preferred polyamines have an average of 10 or more amino groups in one molecule. When the amino group in the molecule has a main chain, a terminal portion, or a branched structure, it can exist in various portions such as a branched portion and a side chain portion. Here, -NH ₂ that does not form an amide and an amino group, -NH
-Means N with 3 monovalent bonds.

Some polyamines have a polymer structure in the form of a large number of polymerized monomer units. The use of polyamines having a polymeric structure is a preferred choice in the present invention. While polyethylene imine as an example, polyethyleneimine is a polyamine-based polymer to monomer units (-CH ₂ -CH ₂ -NH-). Polyvinylamine having a nitrogen atom in the side chain of the polymer (monomer unit is -CH _2-
CH (NH ₂ )-) and polyallylamine (monomer unit is
_{-CH 2 -CH (CH 2 NH 2} ) -) , and others.

[0064] polyamines having the structure of the polymer is generally can be represented by the structural formula of _{R- (C t H u N v} ) w -R '. According to the definition mentioned above, w can be 1 or more. As a preferred condition t is an integer of 2 or more and 10 or less, u is an integer of 5 or more and 25 or less, v is an integer of 1 or more and 5 or less, w is an integer of 2 or more and 200,000 or less, R, R '
Are independently a hydrogen atom, an amino group, or a hydrocarbon group having 1 to 20 carbon atoms. When R and R'are hydrocarbon groups, some hydrogen atoms may be replaced with hydroxyl groups. For example, it may be a hydrocarbon group having a hydroxyl group such as a hydroxyethyl group, a hydroxypropyl group, a dihydroxypropyl group, a hydroxybutyl group and a hydroxyphenyl group.

In the examples of the present invention, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., average molecular weight) was used as the polyamine.
70,000) was preferred. Inferring from the action of polyethyleneimine discussed later, even if polyvinylamine or polyallylamine is used, the same action (effect) as polyethyleneimine can be expected.

Regarding the lower limit and the upper limit of the molecular weight of polyamine, it is considered that there is no particular limitation on the use and application as a metal corrosion inhibitor. However, since it is considered that the molecular weight becomes very small and toxicity problems arise when approaching ethylenediamine or diethylenetriamine, for example, the preferable lower limit of the molecular weight is the molecular weight that makes it difficult to pass through the cell membrane. In the case of general low-molecular weight compounds, when the molecular weight is about 600 or more, it is difficult to pass through the cell membrane. Therefore, the lower limit of the molecular weight of the polyamine can be set to 600 as a guide. There is essentially no upper limit to the molecular weight as long as it is water-soluble and soluble in organic solvents. However, the molecular weight of polyethyleneimine, which is an example of industrially obtained polyamine, is about 70,000, and the molecular weight of polyallylamine is about 10,000 or more and 100,000 or less. Thus, for example, when considering the preferred molecular weight,
It is possible to set a range of 0.0085 times or more and 100 times or less centering on a molecular weight of 70,000, preferably 0.01 times or more and 100 times or less, and more preferably that range.
The range of 0.1 times or more and 10 times or less may be used. Previously, w was an integer of 2 or more and 200,000 or less, but only in the case of polyethyleneimine or polyallylamine,
The ranges of w corresponding to the three types of molecular weight ranges shown here are 10 or more and 163,000 or less, 12 or more and 163,000 or less, and 120, respectively.
It is safe to set the value above 16300.

Other polyamines include H ₂ N- (CH ₂ CH
₂ O) _x -NH ₂ (x = 13 when the molecular weight is around 600), H ₂ N- {CH ₂ CH
₂ (CH ₃ ) O} _x -NH ₂ (x = 10 when the molecular weight is about 600) can also be exemplified.

Polyamine and mercaptoester carboxylic acid salt used in the present invention Structural formula (3)

[0069]

[Chemical 12]

Is preferably obtained by reacting a polyamine such as polyethyleneimine or polyallylamine or polyvinylamine with a mercaptoester carboxylic acid. Examples of mercaptoester carboxylic acids are given above. The reaction of polyamine and mercaptoester carboxylic acid is a neutralization reaction of a base and an acid, and occurs by mixing them. The reaction can be carried out without solvent or with water or an aqueous solvent or an organic solvent. Examples of usable aqueous solvents include hydrated methanol, hydrated ethanol, hydrated propanol, hydrated ethylene glycol, hydrated alcohol such as glycerol, hydrated acetone, hydrated methyl ethyl ketone, hydrated dimethoxyethane and the like.
Examples of usable organic solvents are methanol, ethanol, propanol, butanol, ethylene glycol,
Alcohols such as glycerol, diethyl ether,
Ethers such as diisopropyl ether, tetrahydrofuran and dimethoxyethane, ketones such as acetone, methyl ethyl ketone and cyclohexane, hydrocarbons such as hexane, benzene, toluene and xylene, halogenated hydrocarbons such as dimethyl ether, dichloromethane, chloroform and carbon tetrachloride. , Esters such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, etc. Others such as acetonitrile. The salt formed may precipitate depending on the type of solvent, but this does not cause any problem.
The reaction temperature may be any temperature as long as it does not decompose the polyamine or mercaptoester carboxylic acid. Practical reaction temperature is 0 to 100 ℃, 0
To about 50 ° C is preferable, and about 10 to 40 ° C is more preferable. The reaction amount ratio of polyamine and mercaptoester carboxylic acid is basically 1: 1 in equivalence ratio when forming a normal salt, but when making a basic salt, it is 1: 1 in equivalence ratio to 1: 1 in molar ratio. It is possible in the range up to. Therefore, when making a salt, the range of the value of s in the structural formula (2) is 1 or more and w + 2 or less.

Polyamines are usually treated as a single substance, but they are not only aggregates of (high) molecules having different sizes at the molecular level, but also the reactivity of existing amino groups is not uniform. Therefore, when synthesizing a salt of a polyamine and a mercaptoester carboxylic acid, a part of the reaction mixture is taken as an aqueous solution and one of the polyamine and the mercaptoester carboxylic acid is checked while checking the hydrogen ion concentration with a pH test paper or a pH meter. Adding and reacting with the other is one of the practical choices. According to this method, various salts that show acidity to basicity in water or a mixture containing salts can be synthesized, and the acidity or basicity can be selected according to the purpose of use.

In the present invention, a mixture of polyamine and mercaptoester carboxylic acid can also be used. Further, it is considered that the salt formed from polyamine and mercaptoester carboxylic acid dissociates in water. Taking these into consideration, the ratio of the mixing amount of polyamine and mercaptoester carboxylic acid, the ratio of the reaction amount, or the ratio of the used amount is from 10: 1 to 1:10 by weight and from 300: 1 depending on the situation. It does not matter if it is 1: 100.

When forming a salt of a polyamine and a mercaptoester carboxylic acid, a mercaptoester carboxylic acid salt can be used in addition to the mercaptoester carboxylic acid. For example, ammonium mercaptoester carboxylate is believed to react with polyamines to liberate ammonia and form salts of polyamines. Alternatively, metathesis of salts may be caused, and a metal salt of a mercaptoester carboxylic acid such as sodium mercaptoestercarboxylate may be reacted with a salt of polyamine, for example, a hydrochloride or a sulfate.

The mixture of the polyamine (salt) and the mercaptoester carboxylic acid (salt) used in the present invention can be prepared by mixing the two without solvent or in the presence of water or an aqueous solvent or an organic solvent. The mixing ratio of the two is preferably selected within the range of 3: 1 to 1: 3 by weight ratio, but may be selected within the range of 10: 1 to 1:10, depending on the situation. It does not matter if you select from 300: 1 to 1: 100. The aqueous solvent and organic solvent that can be used are the same as the aqueous solvent and organic solvent that can be used when a salt is formed by reacting a polyamine and a mercaptoester carboxylic acid. When a salt of polyamine is used here, a basic salt or a normal salt can be selected according to the purpose. Examples of the basic salt or the normal salt include fatty acid salts such as hydrochloride, sulfate, phosphate, borate, carbonate, formate, and acetate, higher fatty acid salts such as palmitate and stearate, and amber. Those having various acid residues and polyamine residues such as acid salts, fumarate salts, maleate salts, benzoate salts, and phthalate salts can be used. In addition, examples and preferable examples of the mercaptoester carboxylic acid (salt) are described above as the compound represented by the structural formula (1), the structural formula (2) or the structural formula (4).

The polyamine (salt) and the mercaptoester carboxylic acid (salt) can be easily mixed or reacted in water or in an aqueous solvent or an organic solvent. The aqueous solvent and organic solvent that can be used are the same as the aqueous solvent and organic solvent that can be used when a salt is formed by reacting a polyamine and a mercaptoester carboxylic acid. Therefore, as a method of using the present invention, polyamine (salt) and mercaptoester carboxylic acid (salt) are charged at the same time to be present,
That is, a method for preventing metal corrosion, which is characterized by mixing or reacting both at the application site, is also possible. This is because a dilute solution is usually formed in this case, but a composition containing the polyamine (salt) and the mercaptoester carboxylic acid (salt) or a salt of the polyamine and the mercaptoester carboxylic acid is formed.

The feature of the salt or mixture of the present invention for preventing metal corrosion is that the polyamine (salt) as the raw material thereof is used.
It cannot be inferred from the respective characteristics of mercaptoester carboxylic acid (salt). Example 12 (MEPh-PE
In the case of I), the polarization resistance increased by 2070 Ω after 20 minutes. In the case of polyamine alone, even at a concentration condition of 10 ppm, 19
It was an increase of 0Ω. Since an increase of 840Ω was observed in the mercaptoester carboxylic acid alone (Example 2), the sum of the increased polarization resistance was estimated to be at most 1030Ω.
The increase in polarization resistance 2070 Ω actually measured in Example 12 is much larger. The increase in polarization resistance of Example 13 (METm-PEI) of 1810Ω was also larger than the sum of the increase of polarization resistance of Example 3 of 850Ω and the effect of polyethyleneimine alone. These data are considered to mean that polyethyleneimine itself has a small effect of preventing corrosion, but has an action of enhancing the effect of mercaptoester carboxylic acid (salt). That is, it is considered that polyethyleneimine acts as a synergist.

When the molecular structure of polyethyleneimine is examined in detail, it is composed of an amino group part and an ethylene chain part, but the ethylene chain is also present in the mercaptoethyl groups of MEPh and METm used in the examples. Therefore, it can be presumed that the amino group portion present in the polyethyleneimine molecule has a synergistic effect on the corrosion prevention. Even in polyamines such as polyvinylamine and polyallylamine, since amino groups are present under conditions similar to those of polyethyleneimine, the same action as polyethyleneimine can be expected.

When the mercaptoester carboxylic acid is used as a polyamine salt or the mercaptoester carboxylic acid (salt) is mixed with the polyamine (salt) in the test of the present invention, the mercaptoester carboxylic acid (salt) or the polyamine (salt) is used. It has been found that the polarization resistance is higher than that when each of these is used alone. A large polarization resistance means a large corrosion prevention effect. Therefore, the usefulness of the mercaptoester carboxylic acid polyamine salt or mercaptoester carboxylic acid (salt) -polyamine (salt) mixture of the present invention is clear.

The mercaptoester carboxylic acid (salt) of the present invention, the polyamine salt or mixture thereof, and the metal corrosion inhibitor using them have been described above. The metal corrosion inhibitor composition of the present invention increases corrosion resistance to prevent corrosion. Therefore, the present invention can be applied to general metals other than iron, such as iron, carbon steel, and stainless steel, and iron-based metals such as iron alloys, which are expected to have an action of increasing polarization resistance. Applicable objects include, in addition to the above iron-based metals, for example, copper alloys such as copper, brass, and white copper, zinc and zinc alloys, magnesium and magnesium alloys, aluminum and aluminum alloys, nickel and nickel alloys, chromium and chromium alloys. , Lanthanoids such as neodymium and samarium and their alloys, other lead, tin, manganese, cobalt, molybdenum,
Examples thereof include tungsten, vanadium, cadmium, and alloys thereof.

The method of using the metal corrosion inhibitor of the present invention can be roughly classified into two types. One is to prevent corrosion of metals existing in water or in contact with a liquid such as an aqueous medium, an oil agent, or fuel oil. In this case, it is preferable to add and dissolve or disperse a metal corrosion inhibitor in the liquid with which the metal is in contact. The other is to use the target metal surface requiring protection as it is or after being diluted with an organic solvent. The coating method may be selected freely such as brush coating or dipping method. Organic solvents used for dilution include alcohols such as methanol, ethanol, propanol and butanol, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran and dimethoxyethane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, benzene, toluene, xylene and hexane. Various hydrocarbons, esters such as methyl acetate, ethyl acetate and butyl acetate, and halogenated carbons such as dichloromethane, chloroform and carbon tetrachloride, and acetonitrile can be used depending on the situation. It can also be applied as a spray. In this case, it can be used as it is or after the diluted organic solvent described in the above method is atomized with air or the like. Further, as a spray agent for a container such as a can, it can be used by filling it in a container together with a substance usually used as a propellant such as propane, butane, and dimethoxyethane, and spraying it in a mist state if necessary. The metal corrosion inhibitor of the present invention applied to the surface of an object by a method such as coating or spraying can exert the effect as it is, but can be dried at room temperature or in an inert gas such as nitrogen or argon at room temperature or by heating. You may make it exhibit the corrosion prevention effect.

[0081]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The mercaptoester carboxylic acid used was MEP
Abbreviated as h, METm, and MEDS, their chemical structures are as follows. MEPh: HSCH ₂ CH ₂ OCOC ₆ H ₄ COOH (C
₆ H _4: o-phenylene _{chain) METm: HSCH 2 CH 2 OCOC} 6 H 3 (COOH) 2 MEDS: HSCH 2 CH 2 OCOC 2 H 3 (C 12 H 23) COOH (COC 2 H 3 (C
₁₂ H ₂₃ ) COOH: dodecenyl succinic acid residue) [Example 1] Synthesis of monomercaptoethyl dodecenyl succinate: 26.6 g (100 mmol) of anhydrous dodecenyl succinic acid
e) and 7.8 g (100 mmole) of mercaptoethanol were mixed and heated at 110 ° C. for 3 hours to obtain 34.6 g of a product. The dodecenyl group C ₁₂ H ₂₃ present in the dodecenyl succinic anhydride used here had a branched structure.

This product was dissolved in deuterated chloroform to give ¹
1 H NMR spectrum (200 MHz) was measured. The signals assigned to be derived from dodecenylsuccinic acid residues or SH groups were δ 0.86 ppm (broad singlet derived from non-allyl terminal CH ₃ structure), δ 0.9 to 1.7 ppm (-SH, -CH ₂ -, -CH-
, Complex signal derived from allylic terminal CH ₃ ), δ 2 ppm
Near (allyl position -CH- or allylic -CH ₂ - broad signal of origin), δ2.5 ppm vicinity (succinic acid structure> CH
-CH ₂ -broad signal attributed to origin), δ4.9ppm
And δ 5.3 ppm (broad signal derived from -CH = CH- of the dodecenyl group). The signal attributed to be derived from the hydrocarbon chain of the mercaptoethanol residue is δ2.72 ppm
_{(-CH 2 S-, dt, 2H} ), 4.19 ppm (-OCH 2 -, t, 2H)
Met. ¹ H of 2-mercaptoethanol for comparison
The NMR spectrum was also measured, but CH ₂ S was 2.68 ppm, and OCH
₂ showed a signal at 3.71 ppm. From this NMR spectrum, the product synthesized in this example was confirmed to be monomercaptoethyl dodecenyl succinate. [Example 2] The effect of MEPh on the polarization resistance of the iron electrode was measured by the method described in Reference Example 1 under anaerobic conditions. The concentration of MEPh was 14.2 μmole / liter (3.2 ppm). The polarization resistance was 90 Ω before the addition, but 930 Ω (metal corrosion prevention ability 90.3%) 20 minutes after addition, 1360 Ω (metal corrosion inhibition ability 93.4%) one hour after addition, and almost 24 hours after addition. The maximum value was 3600 Ω (metal corrosion prevention ability 97.5%). [Example 3] The effect of METm on the polarization resistance of the iron electrode was measured by the method described in Reference Example 1 under anaerobic conditions. The concentration of METm is 14.2 μmole / liter (3.8ppm)
And The polarization resistance before addition was 90 Ω.
940 Ω (mineral corrosion prevention ability 90.4%) after 1 minute, 1290 Ω (metallic corrosion inhibition ability 93.0%) 1 hour after addition, 520 after 24 hours
It showed 0 Ω (metal corrosion prevention ability 98.3%). [Example 4] The effect of MEDS on the polarization resistance of the iron electrode was measured by the method shown in Reference Example 1 under anaerobic conditions. MEDS concentration is 14.2 μmole / liter (4.9 ppm)
And The polarization resistance before addition was 90 Ω.
After 30 minutes, it showed 3080 Ω (metal corrosion prevention ability 97.1%), 1 hour after addition, 4850 Ω (metal corrosion inhibition ability 98.1%), and after 24 hours, almost maximum value 11500 Ω (metal corrosion inhibition ability 99.2%). . [Example 5] The effect of MEPh on the polarization resistance of the cold-rolled steel plate electrode was measured in the air atmosphere by the method shown in Reference Example 2, and the effect of preventing metal corrosion was evaluated. The polarization resistance was 89 Ω (metal corrosion inhibiting ability 80%) 20 minutes after the addition, and 122 Ω (metal corrosion inhibiting ability 85.2%) 1 hour after the addition.
The metal corrosion prevention ability shown here was calculated based on the fact that the polarization resistance of the cold-rolled steel plate electrode was usually 18 Ω under these measurement conditions. [Example 6] The effect of the METm on the polarization resistance of the cold-rolled steel plate electrode was measured in the air atmosphere by the method shown in Reference Example 2 to evaluate the effect of preventing metal corrosion. The polarization resistance was 145 Ω (metal corrosion inhibiting ability 87.6%) 20 minutes after addition, and 180 Ω (metal corrosion inhibiting ability 90.0%) 1 hour after addition. The metal corrosion prevention ability shown here was calculated based on the fact that the polarization resistance of the cold-rolled steel plate electrode was usually 18 Ω under these measurement conditions. [Example 7] The effect of MEDS on the polarization resistance of a cold-rolled steel plate electrode was measured in the air atmosphere by the method shown in Reference Example 2 to evaluate the effect of preventing metal corrosion. Polarization resistance is 1110 Ω (metal corrosion prevention capacity 98.4%) 20 minutes after addition,
One hour after the addition, it was 765 Ω (metal corrosion inhibiting ability 97.6%). The metal corrosion prevention ability shown here was calculated based on the fact that the polarization resistance of the cold-rolled steel plate electrode was usually 18 Ω under these measurement conditions. [Example 8] By the method described in Reference Example 3, the effect of MEDS for preventing aluminum corrosion was examined. After 5 days, the aluminum foil test piece was collected and examined, but the surface was only slightly whitened. By comparison with the case where MEDS was not added (Comparative Example 1), it was clear that MEDS had a high corrosion inhibiting effect. Example 9 By the method shown in Reference Example 3, the effect of MEPh for preventing aluminum corrosion was examined. After 5 days, the aluminum foil test piece was collected and examined, but the surface was slightly whitened. By comparison with the case where MEPh was not added (Comparative Example 1), it was clear that MEDS had a high corrosion inhibiting effect. [Example 10] The corrosion inhibitory effect of METm on aluminum was examined by the method shown in Reference Example 3. After 5 days, the aluminum foil test pieces were collected and examined, but no change in appearance was observed.
Therefore, it was found that METm has a particularly high corrosion inhibiting effect. Example 11 Monomercaptoethyl phthalate (MEPh)
Of Polyethyleneimine (PEI) Salt of. This experiment was conducted to demonstrate that a salt is formed from mercaptoester carboxylic acid and polyethyleneimine. In order to make it easy to measure the mass balance, PEI used did not contain water (Nippon Shokubai Co., Ltd., Epomin SP-012, number average molecular weight 1200). Although the molecular weight of PEI used here was not large, the reactivity with acid as a base was equivalent to that of higher molecular weight PEI.

A solution obtained by adding 2 ml of methanol to 1.137 g (5 mmole) of MEPh was mixed with a solution obtained by adding 2 ml of methanol to 265 mg of PEI (5 mmole based on amine value). 1.410 g (theoretical yield of 1.4) of this solution was obtained by evaporating methanol under reduced pressure at room temperature.
02 g) of solid was obtained. The obtained solids were insoluble in water, acetone, etc., and showed different properties from those of MEPh and PEI.

A part of the obtained solid product was dissolved in deuterated methanol and ¹ H NMR spectrum (200 MHz) was measured. -CH the PEI residues ₂ - showed signals for broad complex shapes δ2.8 ppm. The NMR spectrum of PEI was also measured for comparison, but -CH _2- showed a wide complex signal at δ 2.68 ppm. The state of signal shift in the NMR spectrum means that the PEI salt of MEPh was produced from MEPh and PEI. [Example 12] The effect of MEPh-PEI on the polarization resistance of the iron electrode was measured by the method described in Reference Example 1 under anaerobic conditions. The concentration of MEPh is 14.2 μmole / liter (3.21
ppm), the concentration of PEI is 28.4 μeq / liter (1.58 pp
m). The polarization resistance before addition was 90 Ω.
After 20 minutes, it showed 2160 Ω (metal corrosion prevention ability 95.8%), 1 hour after addition, 3280 Ω (metal corrosion inhibition ability 97.3%), and 16 hours later, almost maximum value of 6750 Ω (metal corrosion inhibition ability 98.7%). [Example 13] The effect of METm-PEI on the polarization resistance of the iron electrode was measured by the method described in Reference Example 1 under anaerobic conditions. The concentration of METm is 14.2 μmole / liter (3.8
4 ppm), the concentration of PEI is 28.4 μeq / liter (1.58 pp
m). The polarization resistance before addition was 90 Ω.
After 20 minutes, 1900Ω (metal corrosion prevention ability 95.3%), 1 hour after addition, 2820Ω (metal corrosion inhibition ability 96.8%), and 16 hours later, almost maximum value of 5600Ω (metal corrosion inhibition ability 98.4%). Comparative Example 1 Corrosion of aluminum was examined by using the test solution having the basic composition by the method shown in Reference Example 3. After 5 days, the aluminum foil test piece was collected and examined, but severe corrosion such as whitening of the surface and formation of many corrosion holes was observed. [Reference Example 1] The corrosion inhibiting ability of iron under an anaerobic condition has a diameter of 9.
It was evaluated by measuring the polarization resistance (Rp) when an iron electrode having a length of 5 mm and 12.1 mm was immersed in the electrolytic solution. The electrolyte is carbonate buffer (20 mmole / liter, pH 6.0), Na ⁺ (823 mmole / liter), K ⁺ (12.8 mmole / liter), Mg ²⁺ (10.3 mmole)
/ Liter), Ca ²⁺ (33.7 mmole / liter), Sr ²⁺ (1.
39 mmole / liter), Ba ²⁺ (3.20 mmole / liter),
Deoxidized oxygen containing Cl ⁻ (932 mmole / liter) was used. To measure the polarization resistance, install two electrodes in the electrolyte,
It was calculated according to Ohm's law based on the voltage change between the electrodes, which was observed when a current of 50 nA was applied between the electrodes.

Since the corrosion rate is inversely proportional to the polarization resistance, the corrosion inhibiting ability was calculated according to equation 1.

Corrosion Inhibition Ability = (Rp sample−Rp cont) / Rp sample (Equation 1) where Rp cont is Rp before addition of the corrosion inhibitor.
(Ω), Rp sample is Rp after addition of corrosion inhibitor
(Ω). In Examples and Comparative Examples of the present invention, the numerical value of Formula 1 was multiplied by 100 to show the corrosion prevention ability in percentage. [Reference Example 2] In this example, the measurement operation in an air atmosphere was described. Corrosion-preventing ability of steel sheet is covered by a film, leaving a portion of 25 mm in the length direction of clean cold-rolled steel sheet (JIS G 3141 thickness 0.8 mm, width 70 mm, length 150 mm) as an electrode,
It was evaluated by measuring the polarization resistance when immersed in the electrolytic solution.
The electrolytic solution was a 3% aqueous sodium chloride solution containing acetic acid (5 mmole / liter) and sodium acetate (5 mmole / liter). Since the electrolyte is a buffer system of acetic acid-sodium acetate, the pH stability is high, and the pH is pKa (4.8) of acetic acid.
It was estimated to be the degree. The concentration of the mercaptoester carboxylic acid sample was 0.1%. Polarization resistance can be measured with electrolyte 2
The number of electrodes was set and calculated according to Ohm's law based on the voltage change between electrodes observed when a current of 500 nA was applied between the electrodes. The corrosion inhibition ability was calculated according to Equation 1. In Examples and Comparative Examples of the present invention, the numerical value of Formula 1 was multiplied by 100 to show the corrosion prevention ability in percentage. [Reference Example 3] The corrosion prevention effect of aluminum was examined by immersing an aluminum foil test piece in a test solution containing a 0.02% (200 ppm) sample for 5 days in an air atmosphere and observing the state of the test piece. The basic composition of the test solution is acetic acid (concentration 5 mmol
e / L) and a 3% sodium chloride aqueous solution containing sodium acetate (5 mmol / L). Therefore, the pH of the test solution was about the same as the pKa (4.8) of acetic acid.

[0087]

The mercaptoester carboxylic acid (salt) of the present invention is useful as a high performance metal corrosion inhibitor. Since mercaptoester carboxylic acid (salt) has an ester bond in its molecular structure, it is expected that it will be easily decomposed by the action of chemicals or organisms. The mercaptoester carboxylic acid polyamine salts and mercaptoester carboxylic acid (salt) -polyamine (salt) mixtures of the present invention are also useful as high performance metal corrosion inhibitors.

Claims (5)

[Claims] 1. A mercaptoester carboxylic acid (salt) represented by the following structural formula (1): (However, in the structural formula (1), C _n H _m and C _I H _j mean a hydrocarbon chain, n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, and I is 8 or more and 25 or less. The following integers, j is an integer of 0 or more and 2I + 1-k-z or less, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, and M is hydrogen or a metal or ammonium, that is,
Means ammonium derived from NH ₄ and amines). 2. A mercaptoester carboxylic acid (salt) represented by the following structural formula (2): (However, in structural formula (2), C _n H _m and C _i H _j mean a hydrocarbon chain, n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, and i is 2 or more and 25 The following integers, j is an integer of 0 or more and 2i + 1-k-z or less, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, M is hydrogen or a metal or ammonium, that is,
A metal corrosion inhibitor characterized by containing a mercaptoester carboxylic acid (salt) represented by NH ₄ or ammonium derived from amine). 3. A salt obtained by mixing a polyamine (salt) and a mercaptoester carboxylic acid (salt) represented by the following structural formula (2) and / or a mixture of both: embedded image (However, in the structural formula (2), C _n H _m and C _i H _j mean a hydrocarbon chain, n is an integer of 1 or more and 12 or less, m is an integer of 2 or more and 2n or less, i is 2 or more and 25 or more. The following integers, j is 0 or more 2i + 1-k-z
The following integers, k is an integer of 1 or more and 5 or less, z is an integer of 1 or more and 5 or less, M is hydrogen or metal or ammonium
Shows ammonium derived from NH ₄ and amines). 4. A mercapto represented by the following structural formula (3):
Polyamine salts of ester carboxylic acids: [Chemical 4] (However, in structural formula (3), C_nH_m , C_iH_j Is a hydrocarbon
Means a chain, n is an integer of 1 or more and 12 or less, m is 2 or more and 2n or less
Integer, i is an integer from 2 to 25, j is from 0 to 2i + 1-k-z
The following integers, k is an integer from 1 to 5 and z is an integer from 1 to 5
Is a number, and R− (C _tH_uN_v)_w-R 'means polyamine
Where t is an integer from 2 to 10 and u is an integer from 5 to 25.
Is a number, v is an integer from 1 to 5 and w is from 2 to 200,0
It is an integer of 00 or less, and R and R'are independently a hydrogen atom or an atom.
A mino group or a hydrocarbon group having 1 to 20 carbon atoms
, And s is a number from 1 to w + 2). 5. A metal corrosion inhibitor composition comprising the salt and / or mixture according to claim 3 and the salt according to claim 4.