JPH0617268A - Anticorrosive agent - Google Patents

Abstract

The present invention relates to corrosion inhibitors which are characterised by a content of amine-free salt of a half-ester of an alkylsuccinic or alkenylsuccinic acid, the alkyl or alkenyl substituents thereof containing 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Corrosion inhibitors are used in many areas of metalworking when the metal parts used are to be protected against rust.

[0002]

2. Description of the Related Art Conventional anticorrosive agents are petroleum sulfonates, alkylsulfonamidocarboxylic acids and alkyl
-Or containing components such as amine salts of monoesters of alkenyl succinic acid. Lubricating compositions having rust resistance and based on amine salts of monoesters of alkyl- or alkenylsuccinic acids are disclosed in DE-A-2,640,854. Alkylaryl sulfonic acids, alkanolamines and alkyl-
Alternatively, anticorrosion agents based on monoesters of alkenyl succinic acid are disclosed in EP-A-336,467.

[0003]

It has been found that sulfur-containing compounds, such as salts of alkylaryl sulphonic acids, petroleum sulphonates or alkylsulphonamide carboxylic acids, can be easily decomposed by microorganisms such as sulfur-reducing bacteria. . Nitrogen-containing anticorrosive agents, especially secondary amines, may be converted, for example chemically, into nitrosamines which pose a health hazard.

It is possible to obtain nitrogen-free, in particular amine-free anticorrosion agents, which ensure that their use poses no health risk, especially when considering the use of health-acceptable anticorrosion agents. is important.

The object of the present invention is to provide anticorrosion agents which are amine-free and whose use does not lead to the formation of substances which constitute a health hazard such as nitrosamines. Is.

[0006]

The present inventors have surprisingly found that salts of alkyl- or alkenyl succinic acid monoesters, especially alkali metal salts and alkaline earth metal salts, can be used as anticorrosive agents. It has been found that this can be done, and the dangers caused by nitrosamines can be avoided.

The present invention is directed to alkyl or alkenyl substituents of 8 to 30 carbon atoms, preferably 9 to 1.
It relates to anticorrosives containing amine-free salts of monoesters of alkyl- or alkenylsuccinic acids with 5 carbon atoms.

Amine-free salts, in particular alkali metal salts and alkaline earth metal salts, are obtained by alkyl- or alkenylsuccinic anhydrides, preferably in equimolar amounts with alcohols, such as alcoholate solutions. A catalyst is added to bring the temperature up to the boiling point of the solution, preferably 2
0 ° C to the above boiling point, particularly preferably 40 to 80 ° C
Obtained by esterification in. The reaction is preferably carried out with a stream of nitrogen gas. After the alcohol has been added, the solution is advantageously stirred at a temperature up to the boiling point of the solution, preferably between 60 ° C. and the boiling point of the solution. A dilute base is added to the resulting monoester until a pH above 7 is reached, preferably around 9.

The above monoesters are derived from alkyl- or alkenyl succinic acids whose alkenyl or alkyl substituents have 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms. Examples of such succinic acids are octenyl-, dodecenyl-hexadecenyl
-, Isooctadecenyl-, or triacontenylsuccinic acid. Substituents may include a polyolefin group such as a tri-, tetra- or pentapropenyl group.

The alcohol used to form the monoester preferably has 1 to 15 carbon atoms and preferably includes an alkyl alcohol (alkanol) such as methanol, ethanol, propanol or butanol. To do.

The base which is reacted with the monoester of the substituted succinic acid is preferably an aqueous hydroxide solution such as sodium hydroxide or potassium hydroxide solution. Aqueous solutions of polyvalent metal hydroxides such as alkaline earth metal hydroxides are also suitable.

The amine-free salt aqueous solution thus obtained can be used directly as an anticorrosive agent without further purification of the alkyl- or alkenylsuccinic acid.

These amine-free salts are useful in aqueous anticorrosive agents, in which case they are preferably from 0.5 to 65% by weight, particularly preferably from 1 to 5% by weight in aqueous solution.
Used at a concentration of 10% by weight. P of the above water-based anticorrosive
The H value is a pH of 7 or higher, preferably about 9.

The amine-free salts can also be used as anticorrosives in the form of mixtures with other compounds. Such anticorrosive agents include, for example: alkyl- or alkenyl succinic acid monoester salts 40-80% by weight, formula R ¹ -O- (CH ₂ CH ₂ O) _n H ( Where R ¹ is C ₁₀ -C ₂₂ -alkyl, C ₁₀ -C ₂₂ -alkenyl or alkaryl, and n is 1 to 10, preferably 1 to 5 ethoxylate 30 30% to 1% by weight of a fatty acid represented by the formula R ² —COOH (wherein R ² is C ₁₀ -C ₂₀ -alkyl or C ₁₀ -C ₃₀ -alkenyl) and the formula R ³ — during CH ₂ -COOH (the above formula, R ³ is _{C 10 - - O- (CH 2} CH 2 O) n C 22 - alkyl, C ₁₀ - C ₂₂ - alkenyl or alkaryl, and to n is 1 to 10 , Preferably 1 to 5) Acid 30-0 wt% This type of anticorrosive agent is identified by showing complete "solubility" in combination with water. When mixed with water, they become fine particle emulsions that can be bright (clear) like opal or cloudy like milk.

Mixtures of the abovementioned amine-free salts of monoesters of alkyl- or alkenylsuccinic acids with ethoxylates, fatty acids and, if desired, ethercarboxylic acids, are preferably mineral oil in an amount of up to 70% by weight, based on total weight, of mineral oil It is used together with and has excellent corrosion resistance.

The preferred mineral oil consists of paraffins, naphthenes and some aromatics and usually exhibits a viscosity of 25 to 30 mm ³ / s measured at 20 ° C. A mixture of the above amine-free salts, ethoxylates, fatty acids and, if desired, ethercarboxylic acids acts as emulsifiers and corrosion inhibitors in mineral oil-containing aqueous metalworking aids. Metalworking aids should also be understood as meaning cooling lubricants.

0.1 to 10% by weight, preferably 1.5% by weight, of amine-free salts of monoesters of alkyl- or alkenylsuccinic acids containing ethoxylates, fatty acids and, if desired, ethercarboxylic acids and mineral oils. Aqueous solutions are preferably used as anticorrosive agents, which give excellent results, especially with regard to stability in hard water.

The test results given in the table below show that the amine-free salts according to the invention act as anticorrosive agents. Table 1 shows the corrosion inhibition effect of the above-mentioned amine-free salt aqueous-alkaline solution.

Table 2 shows the corrosion inhibiting effect of the mixture. The corrosion inhibition effect is determined by the Herbert test (DIN51
360/1) and filter paper test (DIN 51360/2)
Measured by

[0020]

【Example】

 Example 1 Monomethyl sodium tripropenyl succinate 224.0 g (1.0 m of tripropenyl succinic anhydride)
ol) and sodium methoxide solution 0.5 g (30
Wt%) is introduced first. Methanol (industrial grade) 3
5.2 g (1.1 mol) of N₂45 to 55 under the atmosphere
Add at ℃ for about 15 minutes. Next 65 ° C
Continue stirring for 5 hours. Excess methanol 10
Distill off at about 40 mmHg at internal temperature up to 0 ° C
(Distillate: 3.3 g). This gives an orange liquid
250.0 g of product were obtained which contained 33% N
Sodium salt by addition of aqueous aOH solution (pH about 9)
Is converted to. Example 2 Monoisobutyl sodium tripropenyl succinate 224.0 g (1.0 m of tripropenyl succinic anhydride)
ol) is initially introduced and heated to 80 ° C. Iso
74.1 g (1.0 mol) of butanol was added to N₂Under the atmosphere
At 80 ° C. for 30 minutes. Then
Stirring is continued for 5 hours at 105 ° C. by this
297.4 g of an orange transparent liquid are obtained, which is also
It is recommended to add 33% NaOH aqueous solution (pH approx. 9).
It is converted to the sodium salt by. Example 3 Mono-i-propyl sodium tetrapropenyl succinate
ATE Tetrapropenyl succinic anhydride 266g (1.0mo
1) is initially introduced and heated to 80 ° C. i-type
60.1 g (1.0 mol) of ropanol N₂Under the atmosphere
At 80 ° C. over 30 minutes. Then 8
Stirring is continued for 12 hours at 0 ° C. With this
299.2 g of a clear oil are obtained, which is 33%
By adding an aqueous solution of NaOH (pH about 9)
Converted to salt. Example 4 Monoisobutyl sodium tetrapropenyl succine
To tetrapropenyl succinic anhydride 266.0 g (1.0
mol) is initially introduced and heated to 80 ° C. I
Sobutanol 74.1 g (1.0 mol) was added to N ₂atmosphere
Add dropwise below at 80 ° C. for 30 minutes. next
Stirring is continued for 5 hours at 105 ° C. by this
338.4 g of a clear oil are obtained, which is 33%
By adding an aqueous solution of NaOH (pH about 9)
Converted to salt. Example 5 Monomethyl sodium pentapropenyl succinate 348 g of pentapropenyl succinic anhydride (1.0 mo
l) and sodium methoxide solution as catalyst.
5 g (30% by weight) are initially introduced. Methanol
Industrial grade) 26.9 g (0.84 mol) N₂Under the atmosphere
At 50 ° C for about 30 minutes (more or less)
Exothermic reaction). Next, continue stirring at 65 ° C for 4 hours.
To continue. This gives 372.4 g of a brown, transparent oil.
Was obtained, which was a 33% aqueous NaOH solution (pH approx.
It is converted to the sodium salt by the addition of 9). Example 6 Mono-i-propyl sodium pentapropenyl succinate
Pent pentapropenyl succinic anhydride 348 g (1.0 mo
l) is introduced first. i-Propanol 50.5 g
(0.84 mol) to N₂Over 40 minutes in the atmosphere
Add dropwise at 80 ° C. Then 1 at 80 ° C
Continue for 2 hours. This gives a brown transparent oil 39
4.6 g was obtained, which was 33% aqueous NaOH.
Converted to sodium salt by addition of liquid (pH about 9)
It Example 7 Monomethyl sodium C_12/14-Alkenyl succinate C_12/14-138 g of alkenyl succinic anhydride (0.5 m
ol) and sodium methoxide solution 0.25 g (3
0% by weight), and the mixture is heated to 50 ° C.
heat. 16.1 g (0.5 mol) of methanol was added to N₂
Add dropwise under atmosphere at 50 ° C for 15 minutes
It Then, stirring is continued for 5 hours at 65 ° C. this
This gave 148.2 g of a pale yellow transparent liquid, which
The product of Nato was prepared by adding a 33% NaOH aqueous solution.
Converted to selenium salt. Example 8 Monoisopropyl sodium C_12/14-Alkenyl Sakushi
Nate C_12/14-Alkenyl succinic anhydride 414g (1.5m
ol) is initially introduced and heated to 80 ° C. Iso
Propanol 90.2g (1.5mol) N ₂atmosphere
Add dropwise below at 80 ° C. for 30 minutes. Next
Then, stirring is continued at 80 ° C. for 12 hours. By this
503 g of a pale yellow transparent product was obtained.
By adding 33% NaOH aqueous solution (pH about 9)
Converted to sodium salt.

[0021]

[Table 1]

[0022]

[Table 2]

Claims (10)

[Claims] 1. An amine-free salt of a monoester of alkyl- or alkenyl succinic acid in which the alkyl or alkenyl substituent contains 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms. An anticorrosive agent characterized by the above. 2. The anticorrosive agent according to claim 1, wherein the salt is an alkali metal salt or an alkaline earth metal salt. 3. Anticorrosion according to claim 1 or 2, wherein the monoester is a monoester of an alkyl- or alkenyl succinic acid with an alcohol having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms. Agent. 4. The anticorrosive agent according to claim 1, wherein the succinic acid monoester comprises a polyolefin succinic acid, preferably a monoester of tri-, tetra- or pentapropenylsuccinic acid. 5. Aqueous solutions containing 0.5% of amine-free salts of monoesters of alkyl- or alkenylsuccinic acids.
To 65% by weight, preferably 1 to 10% by weight, the anticorrosive agent according to any one of claims 1 to 4. 6. A salt of a monoester of an alkyl- or alkenyl succinic acid according to claim 1, 40 to 80% by weight, of the formula R ¹ —O— (CH ₂ CH ₂ O) _n H ( Wherein R ¹ is C ₁₀ -C ₂₂ -alkyl, C ₁₀ -C ₂₂ -alkenyl or alkaryl, and n is 1 to 10, preferably 1 to 5) 1% by weight, (in the formula, R ² is C ₁₀ - C ₂₀ - alkyl or C ₁₀ - C ₃₀ - alkenyl;) wherein R ² -COOH fatty acid represented by 30 to 1 wt%, and wherein R during CH ₂ -COOH (the above formula, R ³ is _{^{C 10 - - 3 -O- (CH}} 2 CH 2 O) n C 22 - alkyl, C ₁₀ - C ₂₂ - alkenyl or alkaline - a le, and n Is 1 to 10, preferably 1 to 5) Anticorrosive agent according to claim 1 containing 30 to 0% by weight carbon acid. 7. The anticorrosive agent according to claim 6, which contains up to 70% by weight of mineral oil with respect to the total weight. 8. An amine-free salt, an ethoxylate, a fatty acid and, if desired, a mixture of ethercarboxylic acids and mineral oils in an amount of 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the aqueous solution. Or the anticorrosive agent according to 7. 9. Use of amine-free salts of alkyl- or alkenyl succinic acid monoesters, the alkyl or alkenyl substituents of which contain from 8 to 30 carbon atoms, as cooling lubricants or metalworking aids. how to. 10. A method of using the anticorrosive agent according to any one of claims 6 to 8 as a cooling lubricant or a metal working aid.