RU2110613C1 - Corrosion protection means - Google Patents

Abstract

FIELD: corrosion protection. SUBSTANCE: corrosion protection means contains amine-free succinic acid alkyl or alkenyl semiester salt, each hydrocarbyl containing 8-30, advantageously 9-15 carbon atoms. EFFECT: eliminated toxicity of corrosion protection means. 10 cl, 2 tbl

Description

 The invention relates to a means of protection against corrosion, which finds application in various fields of metal processing to protect metal parts from rust.

 Anticorrosion agents used to date contain such constituents as petroleum sulfonates, salts of alkyl sulfamido carboxylic acids and amino salts of a partial ester of alkyl or alkenyl succinic acid.

 Known compositions of lubricants with anticorrosive properties based on amino salts of a partial ester of alkyl or alkenyl succinic acid.

 From European patent A-336467, corrosion protection agents based on alkyl-aryl-sulfonic acids, alkanolamine and a partial ester of alkyl or alkenyl succinic acid are known.

 It has been found that sulfur-containing compounds, such as alkyl-aryl-sulfonic acids, petroleum sulfonates, salts of alkyl-sulfonamido-carboxylic acids, can easily be destroyed by microorganisms, such as sulfur-reducing bacteria. Nitrogen-containing corrosion protection agents, in particular secondary amines, can chemically be converted to nitrosamines harmful to health.

 It is in relation to the use of corrosion-resistant corrosion protection products that it is important to obtain nitrogen-free, especially from amines, products whose use would exclude harmful effects on health.

 It was unexpectedly found that salts, in particular salts of alkali and alkaline earth metals of alkyl or alkenyl succinic acid polyesters, can be used as anticorrosive agents, thereby eliminating the risk of exposure to nitrosamines.

 The subject of the invention are corrosion protection agents characterized by the content of amine-free salts of the half-ester of alkyl or alkenyl succinic acid, the alkyl or alkenyl substituents of which contain 8-30 carbon atoms, preferably 9-15.

Amine-free salts, especially alkali and alkaline earth metal salts, are obtained by esterification of alkyl or alkenyl succinic anhydride with alcohol, preferably in equimolar amounts, if necessary using a catalyst, for example, an alcoholate solution, at temperatures close to the boiling point of the solution, preferably 20 ^o C to the boiling point, particularly preferably 40-80 ^o C. Substitution is carried out preferably by supplying a nitrogen gas. After adding alcohol, the solution is stirred at a temperature below the boiling point, preferably 60 ^° C. below the boiling point of the solution. The resulting half esters are diluted with diluted alkali until a pH of more than 7 is reached, preferably to a pH of about 9.

 The half ester is liberated by alkyl or alkenyl succinic acid, in which the alkenyl or alkyl substituent contains 8-30. Preferably 9-15 carbon atoms. Examples of such succinic acids are octenyl succinic, dodecynyl succinic, hexadecynyl succinic, isooctadecynyl succinic or triacontenyl succinic acids. The substitution group may consist of a polyolefin group, for example a tri-, tetra- or pentapropenyl residue.

 The alcohol used to form the half ester contains 1-15 carbon atoms, preferably 1-4 carbon atoms, and preferably contains alkyl alcohol (alkanol), for example methanol, ethanol, propanol or butanol.

 The alkali which is converted by the half ester of the substituted succinic acid is preferably an aqueous hydroxide solution, for example sodium hydroxide or potassium hydroxide. Also suitable are aqueous solutions of multivalent metal hydroxides, for example alkaline earth hydroxides.

 The thus obtained aqueous solution of amine-free salts can be used directly as an anti-corrosion agent without additional purification of alkyl or alkenyl succinic acid.

 These amine-free salts can be used as aqueous anticorrosion agents, preferably in a concentration of 0.5 to 65 wt.%, Particularly preferably 1 to 10 wt.% Relative to the aqueous solution, the pH of the aqueous anticorrosion agent is more than 7, preferably about 9.

 Amine-free salts can also be used in admixture with other compounds as a means of corrosion protection.

Such a corrosion protection agent may, for example, consist of 40-80 wt.% Salt of a half ester of alkyl or alkenyl succinic acid, 30 - 1 wt.% Hydroxyethylate of the formula R ¹ -O- (CH ₂ CH ₂ O) _n H, where R ¹ - C ₁₀ -C ₂₂ -alkyl, C ₁₀ C ₂₂ -alkenyl or alkaryl, n = 1 to 10, preferably 1 to 5, 30 to 1 wt.% Fatty acid of the formula R ² -COOH, where R ² - C ₁₀ - C ₂₂ -alkyl or C ₁₀ -C ₃₀ alkenyl, 30 - 0 wt.% Carboxylic acid ester of the formula R ³ -O- (CH ₂ CH ₂ O) _n -CH ₂ -COOH, where R ³ - C ₁₀ -C _22- alkyl, C ₁₀ -C ₂₂ -alkenyl or alkaryl, n = 1-10, preferably 1-15.

 Such corrosion protection agents are completely soluble in combination with water. When mixed with water, they form a finely divided emulsion, which can be transparent opal or milky turbid.

 Mixtures of the above amine-free salts of the half-ester of alkyl or alkenyl succinic acid with hydroxyethylates, fatty acids or, if necessary, carboxylic acid esters are preferably used with mineral oils with a mineral oil content of up to 70 wt.% With respect to the total weight, exhibiting good anti-corrosion properties.

As mineral oils, mineral oils are used, consisting of paraffins, naphthenes, and also partially aromatic hydrocarbons with a viscosity of 25-30 mm ² / s at 20 ^o C.

 The above mixtures of amine-free salts, hydroxyethylates, fatty acids and possibly carboxylic esters exhibit emulsification and anticorrosion effects in aqueous mineral processing aids containing mineral oils. Under the auxiliary means of metal processing should also be understood as cooling and lubricating agents.

 0.1-10 wt.%, Preferably 1-5 wt.% Aqueous solutions of amine-free salts of the half-ester of alkyl or alkenyl succinic acid with hydroxyethylates, fatty acids and possibly carboxylic acid esters, as well as mineral oils, are preferably used as protection against corrosion, while they are just in relation to stability to hard water show good results.

 The test results obtained show that the amine-free salts according to the invention have high anticorrosive effectiveness.

 In the table. 1 shows the anticorrosive effect of an aqueous-alkaline solution of an amine-free salt. Tab. 2 shows the anticorrosive effect of the mixture.

 The anticorrosive effect was determined using the Herbert test (DIN 51360/1) and the test using filter paper (DIN 51360/2).

 Example 1. Na salt of tripropenyl succinic acid monomethyl ester.

224 g (1 mol) of tripropenyl succinic anhydride and 0.5 g (30 wt.%) Of sodium methanolate solution are the starting material. At 45-55 ^° C. in a nitrogen atmosphere, approximately 15 minutes, 35.2 g (1.1 mol) of methanol (technical) are added dropwise. Then everything is stirred for 5 hours at a temperature of 65 ^o C. At a pressure of about 40 mm RT.article. the excess methanol is distilled at an internal temperature of up to 100 ^° C (3.3 g distillate). As a result, 250.0 g of an orange liquid product is formed, which is converted to the sodium salt by adding 33% aqueous sodium liquor (pH about 9).

 Example 2. Na-salt of monoisobutyl ether tripropenyl succinic acid.

224 g (1 mol) of tripropenyl succinic anhydride is taken and heated to 80 ^o C. At a temperature of 80 ^o C, 74.1 g (1 mol) of isobutane are instilled in a nitrogen atmosphere for 30 minutes. Then everything is stirred for 5 hours at a temperature of 105 ^° C. 297.4 g of a clear orange liquid are formed, which is converted to the sodium salt by adding 33% aqueous sodium liquor (pH about 9).

 Example 3. Na-salt of mono-i-propyl ester of tetrapropenyl succinic acid.

266 g (1 mol) of tetrapropenyl succinic anhydride is taken and heated to 80 ^° C. At 80 ^° C, 60.0 g (1 mol) of i-propanol are instilled in nitrogen atmosphere for 30 minutes. Then everything is stirred for 12 hours at 80 ^o C. 299.2 g of a clear oil is formed, which is converted by the addition of 33% aqueous sodium liquor to sodium salt (pH about 9).

 Example 4. Na-salt of monoisobutyl ester of tetrapropenyl succinic acid.

266 g (1 mol) of tetrapropenyl succinic anhydride is taken and heated to 80 ^° C. At 80 ^° C, 74.1 g (1 mol) of isobutanol are instilled in a nitrogen atmosphere for 30 minutes. Then everything is stirred for 5 hours at a temperature of 105 ^o C. 338.4 g of a clear oil is formed, which is converted to sodium salt by adding 33% aqueous sodium liquor (pH about 9).

 Example 5. Na-salt of pentapropenyl succinic acid monomethyl ester.

Take 348 g (1 mol) of pentapropenyl succinic anhydride and 0.5 g (30 wt.%) Sodium methanolate solution as a catalyst. At 50 ^° C., 26.9 g (0.84 mol) of methanol (technical) are instilled in a nitrogen atmosphere under nitrogen for about 30 minutes (slightly exothermic reaction). Then everything is stirred for 4 hours at a temperature of 65 ^o C. 372.4 g of a brown clear oil is formed, which is converted to sodium salt by adding 33% aqueous sodium liquor (pH about 9).

 Example 6. Na-salt of mono-i-propyl ester of pentapropenyl succinic acid.

348 g (1 mol) of pentapropenyl succinic anhydride is taken. At 80 ^° C, 50.5 g (0.84 mol) of i-propanol are instilled in a nitrogen atmosphere for about 40 minutes. Then everything is stirred for 12 hours at a temperature of 80 ^o C. 394.6 g of a brown clear oil is formed, which is converted to sodium salt by adding 33% aqueous sodium liquor (pH about 9).

Example 7. Na salt of a monoisopropyl ester of C ₁₂ -C ₁₄ alkenyl succinic acid.

138 g (0.5 mol) of C ₁₂ -C ₁₄ alkenyl succinic acid anhydride and 0.25 g (30 wt.%) Of sodium methanolate solution are taken and heated to 50 ^o C. At a temperature of 50 ^o C, 16 1 g (0.5 mol) of methanol for 15 minutes Then everything is stirred for 5 hours at a temperature of 65 ^o C. 148.2 g of a yellowish clear liquid is formed, which is converted to sodium salt by adding 33% aqueous sodium liquor (pH about 9).

Example 8. Na salt of a monoisopropyl ester of C ₁₂ -C ₁₄ alkenyl succinic acid.

414 g (1.5 mol) of C ₁₂ -C ₁₄ alkenyl succinic acid anhydride is taken and heated to 80 ^° C. At 80 ^° C, 90.2 g (1.5 mol) of isopropanol are instilled in nitrogen for 30 minutes. Then everything is stirred for 12 hours at a temperature of 80 ^o C. 503 g of a yellow transparent product is formed, which is converted to sodium salt by adding 33% aqueous sodium hydroxide (pH about 9).

Claims (10)

 1. A corrosion protection agent containing at least a half ester salt of alkyl or alkenyl succinic acid, characterized in that the salt is free of amines and alkyl or alkenyl succinic acid substituents contain 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms.  2. The tool according to claim 1, characterized in that the salt is a salt of an alkaline or alkaline earth metal.  3. The tool according to claim 1 or 2, characterized in that the complex half-ester is a complex half-ester of alkyl or alkenyl succinic acid and alcohol with 1 to 15 carbon atoms, preferably with 1 to 4 carbon atoms.  4. The tool according to any one of paragraphs. 1-3, characterized in that the succinic acid half ester consists of a polyolefinic succinic acid half ester, preferably tri-, tetra- or pentapropenyl succinic acid.  5. The tool according to claim 1, characterized in that it represents 0.5 to 65.0 wt. %, preferably 1 to 10 wt.% aqueous solution of an amine-free salt of alkyl or alkenyl succinic acid. 6. The tool according to p. 1, characterized in that it contains 40 - 80 wt.% Salt of the complex half-ester of alkyl or alkenyl succinic acid according to claim 1, 30 - 1 wt.% Hydroxyethylate of the formula
R ¹ - O - (CH ₂ CH ₂ O) _n H,
where R ¹ - C _{1 0} - C _{2 2} -alkyl, C _{1 0} - C _{2 2} -alkenyl or alkaryl;
n = 1 to 10, preferably 1 to 5;
30 to 1 wt.% Fatty acids of the formula
R ² - COOH,
where R ² is C _{1 0} is C _{2 0} alkyl or C _{1 0} is C _{3 0} alkenyl. 7. The tool according to claim 6, characterized in that it further comprises up to 30 wt.% Carboxylic acid ester of the formula
R ³ - O - (CH ₂ CH ₂ O) _n - CH ₂ - COOH,
where R ³ is C _{1 0} is C _{2 2} alkyl, C _{1 0} is C _{2 2} alkenyl or alkaryl;
n = 1 to 10, preferably 1 to 5.  8. The tool according to claim 7, characterized in that it contains up to 70 wt.% Mineral oil of the total mass.  9. The tool according to any one of paragraphs.6 to 8, characterized in that it contains 0.1 to 10 wt. %, preferably 1 to 5 wt.% aqueous solution of a mixture of amine-free salt, hydroxyethylate, fatty acid, additionally containing mineral oil.  10. The tool according to claim 9, characterized in that it further comprises a carboxylic acid ester.

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