CA2094556A1

CA2094556A1 - Anticorrosives

Info

Publication number: CA2094556A1
Application number: CA002094556A
Authority: CA
Inventors: Gernot Kremer; Horst Lorke
Original assignee: Hoechst AG
Current assignee: Clariant Produkte Deutschland GmbH
Priority date: 1992-04-22
Filing date: 1993-04-21
Publication date: 1993-10-23
Also published as: EP0566956A1; DE59303348D1; ES2092715T3; CZ287586B6; EP0566956B1; BR9301612A; SK36493A3; JPH0617268A; RU2110613C1; CZ69193A3; ATE140982T1

Abstract

Abstract of the disclosure:

Anticorrosives The present invention relates to anticorrosives, which contain an amine-free salt of a monoester of an alkyl- or alkenylsuccinic acid, the alkyl or alkenyl substituents thereof containing 8 to 30 carbon atoms, preferably 9 to 15 carbons.

Description

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HOECHST AKTIENGESELLSC~FT HOE 92/F 112 Dr.Kl/rh Description Anticorrosives Anticorrosives are used in many areas of metal-working S when the metal parts used are t:o be protected against rust. The hitherto custo~.ary anticorrosives contain components, such as petroleum sulfonates, salts o~
alkylsulfonamidocarboxylic acids and amine salts of a monoester of an alkyl- or alkenylsuccinic acid. ~ubricant compositions having antirust properties and being based an amine salts of a monoester of an alkyl- or alkenylsuccinic acid are disclosed in DE-A-2,S40,854.
Anticorrosives based on alkylarylsulfonic acids, alkanolamine and monoesters of an alkyl- or alkenylsuccinic acid are disclosed in EP-A 336,46~.

It has been found that sulfur-containing compounds, such as alkylarylsulfonic acids, petroleum sulfonates or salts of alkylsulfonamidocarboxylic acids, can be easily degraded by microorganisms, such as sulfur-reducing bacteria. Nitrogen-containing anticorrosives, in par-ticular secondary amines, can be converted, for example chemically, to nitrosamines which constitute a health hazard.

Especially in view of the use of health-compatible anticorrosives, it is important to obtain nitrogen-free, in particular amine-free, anticorrosives which ensure that their use does not constitute a health hazard.

The object of the invention is to provide anticorrosives which are free of amines and which ensure that their use does not give rise to the formation of substances which constitute a health hazard, such as nitrosamines.

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Surprisingly, it has been found that salts, in particular alkali metal salts and alkaline earth metal salts, of alkyl- or alkenylsuccinic monoesters can be used as anticorrosives, thus making it possible to avoid the hazard caused by nitrosamines.

The invention relates to anticorrosives which contain an amine-free salt of a monoester of an alkyl- or alkenyl-succinic acid whose alkyl or alkenyl substituents contain 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms.

The amine-free salts, in particular alkali metal salts and alkaline earth metal salts are obtained by esterific-ation of alkyl- or alkenylsuccinic anhydride with alco-hol, preferably in equimolar amounts, if appropriate with addition of a catalyst, such as an alcoholate solution, at temperatures up to the boiling point of the solution, preferably 20C up to the boiling point, particularly preferably 40-80C. The reaction is preferably carried out with nitrogen gassing. After addition of the alcohol, the solution is advantageously stirred at a temperature up to the boiling point of the solution, preferably 60C
up to th~ boiling point of the solution. Dilute base is added to the monoesters obtained until reaching a pH
above 7, preferably until reaching a pH around 9.

The monoester is derived from an alkyl- or alkenyl-succinic acid in which the alkenyl or alkyl substituentcontains 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms. Examples of such succinic acids are octenyl-, dodecenyl-, hexadecenyl-, isooctadecenyl- or triacontenylsuccinic acid. The substituent group can also comprise a polyolefinic group, such as a tri-, tetra- or pentapropenyl radical.

The alcohol used for forming the monoester preferably has 1 to 15 carbon atoms and preferably contains an alkyl alcohol (alkanol), such as methanol, ethanol, propanol or _ 3 - 2~ 9~ 6 butanol~
The base which is reacted with the monoester of the substituted succinic acid is preferably aqueous hydroxide solution, such as sodium hydroxide or potassium hydroxide solution. Aqueous solutions of polyvalent metal hydrox-ides, such as alkaline earth metlal hydroxides, are also suitable.

The aqueous solution of ~he amine-free salts t~us obtained can be used directly as anticorrosive without any further purification of the alkyl- or alkenylsuccinic acid~
~hese amine-free salts are u~eful in aqueous anti-corrosives, in which they are preferably used in a concentration of 0.5 to 65% by weight, particularly preferably 1-10% by weight, relative to the aqueous solution. The pH of the aqueous anticorrosive is above pH
7, preferably at a pH of about 9.

The amine-free salts can also be used as anticorrosives in a mixture with further compounds.
Such an anticorrosive comprises, for example, 40-80% by weight of a salt of a monoester of an alkyl-or alkenylsuccinic acid, 30-1% by weight of an ethoxylate of the formula Rl-O- ( CH2CH2 ) nH ~
in which R1 is C~0-C22-alkyl, C10-c22-alkenyl or alkaryl and n is 1 to 10, preferably 1 to 5, 30-1% by weight of a fatty acid of the formula R2-COOH, in which R2 is C~0-C20-alkyl or C10-C30-alkenyl, and 30-0% by weight of an ethercarboxylic acid of the formula R3-o-(CH2CH20)n-CH2-COOH~
in which R3 i~ C,0-C22-alkyl, C10-c22-alkenyl or alkaryl, and n is 1 to 10, _ 4 - 2~94~
preferably 1 to 5.

Anticorrosives of this type are distinguished by complete "solubility~' in combination with water. Upon mixing with water, they give finely divided emulsions which can be clear ttransparent) like opal or else cloudy like milk.

Mixtures of the abovementioned 2~ine-free salts of the monoesters of alkyl- or alkenylsuccinic acid with ethoxy-lates, fatty acids and, if desired, ethercarboxylic acids are preferably used together with mineral oils in an amount of up to 70% by weight of mineral oil, relative to the total weight, and show good anticorrosive properties.

Suitable mineral oils are mineral oils composed of paraffins, naphthenes and in part of aromatics and usually exhibiting viscosities of 25 to 30 mm2/s, ~easured 1~ at 20C.

The abovementioned mixtures of amine-free salt, ethoxy-lates, fatty acids and, if desired, ethercarboxylic acids act as emulsifiers and corrosion inhibitors in aqueous metal-working auxiliaries containing mineral oil.
Metal-working auxiliaries are also understood to mean cooling lubricants.

The 0.1-10% by weight, preferably 1.5% by weight, aqueous solution of the amine-free salts of the monoesters of alkyl- or alkenylsuccinic acid containing ethoxylates, fatty acids and, if desired, ethercarboxylic acids and mineral oil are preferably used as anticorrosives, giving good results e~pecially with respect to good stability to hard water.

The test results listed below show that the amine-free salts according to the invention act as anticorrosives.

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Table 1 shows the corrosion-inhibiting effect of an aqueous-alkaline solution of the amine-free salt.
Table 2 shows the corrosion-inhibiting effect of a mixture.
The corrosion-inhibiting effect was determined by the Herbert tests (DIN 51360/1) and the filter paper test (DIN 51360/2).

Example 1 Monomethyl sodium tripropenylsuccinate 224.0 g (1~0 mol) of tripropenylsuccinic anhydride and 0.5 g (30~ by weight) of sodium methoxide solution are initially introduced. 35.2 g (1.1 mol) of methanol (technical grade) are added dropwise at 45-55~C over a period of about 15 minutes under an N2 atmosphere.
Stirring at 65C is then continued for 5 hours. ~xcess methanol is distilled off at about 40 mm Hg at an in-ternal temperature of up to 100C (distillate: 3.3 g).
This gives 250.0 g of an orange-colored liquid product which is converted to the sodium salt by addition of 33%
aqueous NaOH (pH of about 9).

Example 2 Monoisobutyl sodium tripropenylsuccinate 224.0 g (1.0 mol) of tripropenylsuccinic anhydride are initially introduced and heated to 80C. 74.1 g (1.0 mol) of isobutanol are added dropwise at 80C over a period of 30 minutes under an N2 atmosphere. Stirring at 105C is then continued for 5 hours. This gives 297.4 g of an orange-colored clear liquid which is converted to the sodium salt by addition of 33% aqueous NaOH (pH of about 9).

- 6 _ 2~ 6 Example 3 Mono-i-propyl sodium tetrapropenylsuccinate 266 g (1.0 mol) of tetrapropenyLsuccinic anhydride are initially introduced and heated to 80C. 60.1 g (1.0 mol) of i-propanol are added dropwise at 80C over a period of 30 minutes under an N2 atmosphere. Stirring at 80C is then continued for 12 hours. This gives 299.2 g of a clear oil which is converted to the sodium salt by addition of 33% aqueous NaOH (pH of about 9).

Example 4 Monoisobutyl sodium tetrapropenylsuccinate 266.0 g (1.0 mol) of tetrapropenylsuccinic anhydride are initially introduced and heated to 80C. 74.1 g (1.0 mol) of isobutanol are added dropwise at 80C over a period of 30 minutes under an N2 atmosphere. Stirring at 105C is then continued for 5 hours. This gives 338.4 g of a clear oil which is converted to the sodium salt by addition of 33% aqueous NaOH (pH of about 9).

Example 5 Monomethyl sodium pentapropenylsuccinate 3~8 g (1.0 mol) of pentapropenylsuccinic anhydride and 0.5 g (30% by weight) of sodium methoxide solution as the catalyst are initially introduced. 26.9 g (0.84 mol) of methanol (technical grade) are added dropwise at 50C
over a period of about 30 minutes under an Nz atmosphere (slightly exothermic reaction). Stirring at 65C is ~hen continued for 4 hours. This gives 372.4 g of a bxown clear oil which is converted to the sodium salt by addition of 33% aqueous NaOH (pH of about 9).

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Example 6 Mono-i-propyl sodium pentapropenylsuccinate 348 g (1.0 mol) of pentapropenylæuccinic anhydride are initially introduced. 50.5 g (0.84 mol) of i-propanol are added dropwise at 80C over a period of about 40 minutes under an N2 atmosphere. Stirring at 80C is then continued for 12 hours. This gives 334.6 g of a brown clear oil which is converted to the sodium salt by addition of 33%
aqueous NaOH (pH of about 9).

Example 7 Monomethyl sodium Cl2/14-alkenylsuccinate 138 g (0.5 mol) of Cl2/l4-alkenylsuccinic anhydride and 0.25 g (30% by weight) of sodium methoxide solution are initially introduced, and the mixture is heated to 50C.
16.1 g (0.5 mol) of methanol are added dropwise at 50C
over a period of 15 minutes under an N2 atmosphere.
Stirring at 65C is then continued for 5 hours. This gives 148.2 g of a yellowish clear liquid which is converted to the sodium salt by addition of 33% aqueous NaOH (pH of about 9).

Example 8 Monoisopropyl sodium Cl2/l4-alkenylsuccinate 414 g (1.5 mol) of Cl2~14-alkenylsuccinic anhydride are initially introduced and heated to 80C. 90.2 g (1.5 mol) of isopropanol are added dropwise at 80C over a period of 30 minutes under an N2 atmosphere. Stirring at 80C is then continued for 12 hours. This gives 503 g of a yellow clear product which is converted to the sodium salt by addition of 33% aquPous NaOH (pH of about 9)~

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Claims

1. An anticorrosive, which contains an amine-free salt of a monoester of an alkyl- or alkenylsuccinic acid whose alkyl or alkenyl substituents contain 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms.

2. An anticorrosive as claimed in claim 1, wherein the salt is an alkali metal or alkaline earth metal salt.

3. An anticorrosive as claimed in claim 1 or 2, wherein the monoester is the monoester of alkyl- or alkenyl-succinic acid and an alcohol having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms.

4. An anticorrosive as claimed in one of claims 1 to 3, wherein the succinic monoester comprises the mono-ester of a polyolefinic succinic acid, preferably tri-, tetra- or pentapropenylsuccinic acid.

5. An anticorrosive as claimed in one of claims 1 to 4, which contains 0.5 to 65% by weight, preferably 1 to 10% by weight, of an amine-free salt of a monoester of an alkyl- or alkenylsuccinic acid, relative to an aqueous solution.

6. An anticorrosive as claimed in claim 1, which contains 40-80% by weight of a salt of a monoester of an alkyl- or alkenylsuccinic acid as mentioned in claim 1, 30-1% by weight of an ethoxylate of the formula R1-O-(CH2CH2O)nH, in which R1 is Cl0-C22-alkyl, Cl0-C22-alkenyl or alkaryl and n is 1 to 10, preferably 1 to 5, 30-1% by weight of a fatty acid of the formula R2-COOH, in which R2 is C10-C20-alkyl or C10-C30-alkenyl, and 30-0% by weight of an ethercarboxylic acid of the formula R3-O-(CH2CH2O)n-CH2-COOH, in which R3 is C10-C22-alkyl, C10-C22-alkenyl or alkaryl, and n is 1 to 10, preferably 1 to 5.

7. An anticorrosive as claimed in claim 6, which contains up to 70% by weight of mineral oil, relative to the total weight.

8. An anticorrosive as claimed in claim 6 or 7, which contains 0.1-10% by weight, preferably 1-5% by weight, of a mixture of amine-free salt, ethoxylate, fatty acid, and, if desired, ethercarboxylic acid and mineral oil, relative to an aqueous solution.

9. Use of an amine-free salt of a monoester of an alkyl- or alkenylsuccinic acid whose alkyl or alkenyl substituents contain 8 to 30 carbon atoms as coolin lubricant or metal-working auxiliary.

10. Use of an anticorrosive as claimed in claim 6 to 8 as cooling lubricant or metal-working auxiliary.