JPS5891176A - Anticorrosive against calcium chloride brine - Google Patents

Abstract

PURPOSE:To obtain an anticorrosive protecting a metallic material from corrosion due to CaCl2 brine by adding 1 or >=2 kinds of specified N-alkyl substituted alkanolamines or by further adding 1 or >=2 kinds of triazoles. CONSTITUTION:To a CaCl2 brine system are added 1 or >=2 kinds of N-alkyl substituted alkanolamines represented by formulaI(where R<1> is 1-4C alkyl; R<2> is H or 1-3C alkyl; and R<3> is 2-3C alkylene) such as 2-methylaminoethanol and 2-diethylaminoethanol so as to adjust the concn. to 500-5,000ppm or 500- 3,000ppm. To 1 or >=2 kinds of said alkanolamines may be added 1 or >=2 kinds of triazoles such as benzotriazole and alkylbenzotriazole in 1:(0.001-0.02) ratio. The mixed composition is added to a CaCl2 brine system so as to adjust the concn. to 500-5,000ppm or 500-3,000ppm. Superior resistance to corrosion due to CaCl2 brine is provided to a metallic material.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to anticorrosive agents for calcium chloride brines. More specifically, the present invention relates to an anticorrosive agent that exhibits excellent corrosion inhibition effects on various metals, particularly iron metals, using calcium chloride brine.

Calcium chloride brine is widely used as a refrigerant in refrigerators used in various manufacturing plants to cool and keep raw materials, intermediate products, or products cold, and generally a 15-35% by weight calcium chloride aqueous solution is used. However, this aqueous solution is highly corrosive, and although various measures have been taken since ancient times to prevent corrosion of commonly used metals, satisfactory results have not been obtained. In particular, chromic acid-based compounds have been used for iron-based metals, but these are not preferred from the standpoint of pollution control. For example, Japanese Patent Publication No. 53-13179 describes an example using polymerized phosphoric acid and sodium silicate, but these compounds have low solubility in calcium chloride brine, so they cannot be dissolved at low concentrations. It is difficult to obtain the desired effect. Further, JP-A-53-141137 describes a method using zinc salt, but since zinc salt alone has low solubility, the expected effect cannot be obtained at a low concentration where zinc salt is soluble. In addition, special amino compounds are used in some cases, but they are generally expensive and cannot be said to be sufficiently effective compared to their cost.

In view of these points, the inventors of the present invention have conducted extensive research and have discovered that specific N-alkyl-substituted alkanolamines suitably act as anticorrosive agents for iron-based metals in chlorinated brine. Reached. The inventors of this invention conducted further research and found that when specific N-alkyl-substituted alkanolamines and triazoles are used in combination with calcium chloride brine, the anticorrosion effect of the brine system against iron-based metals further increases. We discovered this fact and came up with this invention.

As far as the inventor of this invention is aware, N-substituted alkanolamines are known to exhibit anticorrosive effects as a synergistic agent in soft water systems with low salt content, such as general cooling water, but It is completely unknown that ferrotin has an anticorrosive effect in highly corrosive systems. Furthermore, although it is well known that triazoles have a corrosion-preventing effect on copper-based metals, these compounds alone usually do not exhibit corrosion-preventing effects on iron-based metals.

Thus, this invention provides a formula (D= (wherein R is an alkyl group having 1 to 4 carbon atoms; R is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms; R is a C 2 to 307 V
xylene group)
! Chlorinating power A/ containing 1 or 29 or more as active ingredients
S/? The present invention provides an anticorrosive agent for Mupurine.

Provided is an anticorrosive agent for chlorination power v'y tuf brine, characterized by containing as active ingredients a summer-alkyl A/1111 converted aka-μ amine of the formula (1) and a triacy V-based compound. It is something to do.

Examples of the alkano-V amines substituted with ino-a to be used in this invention include 2-methylaminoethanol, 2-diethylaminoethanol, 2-ethylaminoethanol, 2-dimethylaminoethanol, 2-diimpropylaminoethanol, 2-n- Butylaminoethanol, 3-dimethylaminopropanol, 2-dimethylaminopropanol, 3-diethylaminopropanol, 2-
Diethylaminopropanol is mentioned. Among these, 2-diethylaminoethanol, 2-ethylaminoethanol, 2-dimethylaminoethanol, and 2-n-butylaminoethanol are preferred.

As the triazoles used in this invention, 1311g
Examples include compounds having a small number of five-membered rings containing three children, specifically benzotriazole, triazole, alkylbenzotriazole, alkylaminobenzotriazole, alkylaminosulfonylbenzotriazole, chlorobenzotriazole, naphthobenzotriazole, Mercaptobenzotriazole, hydroxyalkylbenzotriazole, hydropenzotriazo-ν
, aminobenzotriacye J&/, benzotriacye V, naphthotriacye V, etc., or a mixture of two or more thereof. Among these, it is preferable to use benzotriazole and/or tolyltriacykf.

The above-mentioned one-component preparation or two-component preparation used in combination is usually preferably formulated in the form of a liquid solution dissolved in water, but it may also be formulated as a powder using a suitable carrier. When preparing a liquid preparation, it is appropriate to use 5 to 80% by weight of the active ingredient iI in view of the stability of the preparation. In addition, in some cases, a small amount of a hydroxide solution such as sodium hydroxide may be used to dissolve the triazole.

Suitable ratio for the synergistic effect of the alkyl-substituted alkano-amine and the triazole to be exhibited is a direct ratio of 50 to 50 :1~1000:1. Preferably 50:1
~500:1. Incidentally, there is no problem even if some amount of various additives such as stabilizers and dispersants are added to these preparations.

When using a preparation containing one or two of the above-mentioned ingredients as active ingredients, the amount of the preparation to be added to the corrosion protection target, that is, the calcium chloride brine system, depends on the conditions at that time and the composition of the preparation. Although not particularly limited, the amount of active ingredient N-alkyl-substituted alkanolamine or the total amount of the N-alkyl-substituted alkanolamine and triazole mixture relative to calcium chloride brine is usually 500 to 5000 ppm, preferably 500 ppm. The objective can be achieved by adding ~3000 PPm.

Therefore, the present invention also provides a method for preventing corrosion of iron-based metals using a calcium chloride brine, which comprises adding an N-alkyl-substituted alkanolamine alone or in combination with a triazole to the calcium chloride brine. In the case of combined use, each active ingredient may be added separately as a single preparation, or may be added in advance as a mixture preparation.

The anticorrosion agent for calcium chloride brine of the present invention exhibits an excellent effect in inhibiting corrosion of various metals used in calcium chloride brine, especially ferrous metals (e.g., steel, mild steel, cast iron, etc.), and is suitable for use in various industrial brines. Useful. In particular, when triazoles are used in combination, a synergistic effect on iron-based metals is obtained, and an effect on not only iron-based metals but also copper-based metals (eg, copper, brass, gunmetal, etc.) is observed. Therefore, in a brine containing a large amount of copper-based metals, it is preferable to increase the amount of triazoles within the ratio range of this invention. In this case, the desired anticorrosion effect can be obtained by using a lower concentration, and it is useful for various industrial brines.

The present invention will be described in more detail below based on Examples, but the present invention is not limited thereby.

Example 1 (Formulation Example 1) 2-ethylaminoethanol 10 parts by weight Benzotriazole 0.1 #water
89.9 # Mixing and stirring were performed at the above blending ratio to obtain a uniformly dissolved solvent.

(!!li agent example 2) 2-ethylaminoethanol 50 parts by weight Benzotriazole 0.5# water
49.5 # Mixing and stirring were performed at the above blending ratio to obtain a uniformly dissolved solution.

(Formulation Example 3) 2-ethylaminoethanol 20 parts by weight 1, 2.
3-benzotriazole 0.11 acrylic acid methacrylic acid copolymer ll (molecule placement 5ooO) water, 78.
#9 Mixing and stirring were performed at the above blending ratio to obtain a uniformly dissolved solution. In this way, a small amount of a dispersant may be added, and a small amount of a stabilizer or the like may also be added.

Example 2 Industrial calcium chloride bW/V% in beaker (1) volume)
Add 1 part of an aqueous solution containing. [Industrial calcium chloride was used to approximate field conditions. ] After adding a predetermined amount (2000 ppm) of the chemicals shown in Table 1 to this and adjusting the pH to 9 using sodium hydroxide or hydrochloric acid,
A test piece made of soft steel (thickness 1 x 30 x 50) was suspended from a stirring rod and rotated at ioorpm in the liquid. In this state, adjust the temperature to 30℃ using a thermostat and heater.
The test is carried out for 5 days while maintaining the liquid temperature at . After the test, the test piece is immersed in 15% hydrochloric acid for 30 seconds, washed with water and dried, and its weight after the test is measured. Using the pre-measured weight (Iq) before the test and the weight after the test, the corrosion loss per 1 dd per day, that is, m d, d, (''P/
dn@”Y) is calculated.

The drugs used and test results are shown in Table 1.

Table 1 Example 3 According to the method of Example 2, the amount of the drugs shown in Table 2 was added to 100%.
n(d, cl) was calculated by varying the value up to 10,000.

Table 2 Example 4 Corrosion rates were calculated according to the method of Example 2 using the N-alkyl-substituted alkanolamine and triazole agent according to the present invention in the amounts shown in Table 3.

Reference Example Alkanolamines known to the public and according to the present invention were tested using general cooling water as the test liquid according to the method of Example 2 (no calcium chloride was added), and m, d, and d were calculated from the results. We investigated the effects. Each of the drugs listed in Table 4 was added at 2000 ppm.

Table 4 Although the N-alkyl-substituted alkanolamines specified in this invention, as shown in the Examples and Reference Examples, have the same effect as other alkanolamines in the -crotch system, they are not effective against calcium chloride brine. It is understood that this system has an anticorrosion effect that is not seen in these materials. Furthermore, the effect is enhanced by using triazoles in combination.

Claims (1)

[Claims] 1. Formula (T) (wherein, R is an acyl group having 1 to 40 carbon atoms; R is a hydrogen atom or an acyl group having 1 to 30 carbon atoms; R is an acyl group having 2 to 3 carbon atoms; An anticorrosive agent for calcium chloride prine, characterized in that it contains one or more of the iris-acyl-substituted AV-kanolamines represented by (alkylene group) as an active ingredient. 2. M-alkyl-substituted amine is 2-methyaminoethanol, 2-diethylaminoethanol
, 2-ethyaminoethanol v12-dimethylaminoethanol-A/, 2-diisopropyl V-aminoethanol-A/%
2-n-butyV aminoethanol A/, 3-dimethyaminopropano-&, 2-dimethyV aminopropano-A/
, 3-diethy ν aminopropano ν or 2-diethy ν aminopropano V. 94M-A V-substituted alkanolamine to 2-diethyl aminoethanol, 2-ethylaminoethano-A/,
The anticorrosive agent according to claim 1, which is 2-dimethyV-aminoethanol or 2-11-butyV-aminoethanol. 4. Chloride power: 500 to 500 G PpI of N-AVoxy-substituted AV-kanolamine in the sium prine system! The anticorrosive agent according to any one of claims 1 to 3, which is added so that the corrosion resistance of the anticorrosive agent is 1. 5. The anticorrosive agent according to any one of claims 1 to 3, wherein 1M-AyIf-substituted alkanolamine is added to the calcium chloride prine system in an amount of 500 to 30,001. 6, represented by the formula (p (wherein R is an acyl group having 1 to 4 carbon atoms, II is a hydrogen atom or an acyl group having 1 to 30 carbon atoms; R is an aA/aF ren group having 2 to 3 carbon atoms) A corrosion inhibitor for chloride power V sium plines, characterized in that it contains as active ingredients one or more N-alkyl-substituted alkano-y amines and one or more triacye class V 01 class.7. M-779* A/substituted alkanolamine is 2-methylaminoethanol-&, 2-diethylaminoethanol-4/, 2-ethylaminoethano-J/, 2-dimethylaminoethanol, 2-diisopropylaminoethanol-v, 2 -n-butylaminoethano-JL/, 3-dimethylamitubrobanol, 2-diethylaminopropano-v1.3-diethylaminopropano-V or 2-diethylaminopropano-M, the desired range of specific rIf #I The anticorrosive agent according to item 6. 8. The substituted alkano V amine is 2-diethy V amino ! no A/, !-ethy ν amino ethanol A/, 2-dimethy ν amino ethanol or 2- !ll-
The anticorrosive agent according to claim 6, which is butylaminoethanol. 9, triacye w@ is benzotriacye A/, triacye v1 alkyl V benzotriazole, AV kylaminobenzotriacye V, alkyaminos to benzotriacye V, chlorobenzotriazole, naphthobenzotriacye to 1 Captobenzotriazole V, hydroxybenzotriazole A/, hydrobenzotriazole, aminobenzotriazo-ν, carboxybenzotriazole or s7totriazole V The anticorrosive agent described in any of the above. 10. The anticorrosive agent according to item 9, wherein the triacye w@ is benzotriacye V or tolyltriazole. 1t, w-A A/ ji-J1/ Kafu to substitution A w
Mixing ratio with AtyL) rear seas/llI #1:
0.001 to (1-02) Claims 6 to 1
The anticorrosive agent according to any one of item 0. '12. The anticorrosive agent according to any one of Items 6 to 10, wherein the mixing ratio of the 11-alkyl-substituted Ashikat-V amine and Triacye V is 1:0.002 to 0.02. . 18. The sum of M-acyl-substituted amine and triacyl amine and triacyl is 5.
Special F' added to 00 to 5000 m1%
The anticorrosive agent according to any one of items 6 to 12 in which li4 is desired. 14. Any one of claims 6 to 12, which is added to the calcium mide brine system in such a manner that the total amount of %N-AV-kyl-substituted AV-V amine and triazole A/type is 500 to 3000 FPO1. Anticorrosion agent listed in Crab