EP0237959B1 - Water soluble mixtures of ammonium salts from fatty acids and polyol-fatty acids, or of their alcali or ammonium salts, process for their production and their use as corrosion inhibitors in aqueous systems - Google Patents

Abstract

Water-soluble corrosion-inhibiting mixtures containing (a) one or more ammonium salts of fatty acids corresponding to the following general formula <IMAGE> (I) in which n=1 or 2 while R1, R2, R3 and R4 may be the same or different and represent hydrogen, unbranched or branched C1-C6 alkyl groups, C1-C6 hydroxyalkylene groups or C1-C8 aminoalkylene groups and R5 represents C6-C10 alkyl groups, and (b) one or more polyol fatty acids and/or salts thereof corresponding to the following general formula <IMAGE> (II) in which R6 is a C1-C19 alkyl or alkylene group and R7 represents an organic residue formed from a dihydroxy or polyhydroxy compound by elimination of a hydroxyl group, M(+)=H(+), Na(+), K(+) or an ammonium ion [R1R2R3R4N]n+, as in formula (I), and m is an integer of from 0 to 18, and to a process for preparing these water-soluble mixtures and to the use of these mixtures for inhibiting corrosion in drilling oils, cutting oils, rolling oils, grinding oils, metal-cleaning solutions, coolants and lubricants.

Description

The invention relates to water-soluble mixtures of fatty acid-ammonium salts and polyol fatty acids or their alkali metal or ammonium salts, a process for their preparation and the use of such mixtures for corrosion inhibition in aqueous systems.

In technical processes for processing metal surfaces, for example by drilling, cutting, rolling or grinding, as well as in metal cleaning, corrosion problems occur again and again. Here, as well as in technical cooling processes that also play in the presence of water or water-containing liquid mixtures, metals that are at risk of corrosion, primarily iron or iron-containing alloys, come into contact with aqueous technical cleaners, cooling water, cooling lubricants for metalworking, etc. and are corroded under unfavorable conditions. On the one hand, this results in a reduced service life of the equipment, on the other hand, in processes in which the metal surfaces are to be further processed, if necessary with corrosion-protective coatings, complex work processes must be interposed in order to make the already corroded metal surfaces free of corrosion for the subsequent processes put.

From DE-AS 11 49 843 and EP-PS 0 002 780 amine salts or alkanolamine salts of maleic acid and its derivatives are known as corrosion inhibitors in aqueous systems. Depending on the substituent, such compounds have a good water solubility up to sufficient for use in aqueous systems and have a satisfactory corrosion protection effect for the application purposes, but have the disadvantage that they foam extremely strongly. This is especially observed. if the corresponding inhibitors are added to cooling water or cooling lubricants. It was therefore necessary to add a foam damper in connection with such connections. In addition, it was found that such compounds are sometimes extremely sensitive to fluctuations in water hardness.

DE-OS 29 43 963 alkanolamine salts of alkenyl succinic acids are known as corrosion inhibitors in aqueous systems. US Pat. No. 3,374,171 also discloses amine salts of fatty acids having 6 to 9 carbon atoms as water-soluble corrosion inhibitors. Fatty acids such as capronic, caprylic, heptane and pelargonic acid were neutralized with alkanolamines and mixed with polyoxyalkylene glycols.

The neutralization product of di-n-butylamine with a 1: 1 mixture of caprylic acid and capric acid has a better corrosion-inhibiting effect than the fatty acids neutralized with alkanolamines. The disadvantage of this product, however, is that it smells extremely unpleasant. Due to the large surfaces that are treated with such corrosion inhibitors, there is an unacceptable odor nuisance.

The object of the present invention was to provide a water-soluble corrosion protection agent which leads to good corrosion inhibition on metallic surfaces made of iron or iron-containing alloys. In addition, the lowest possible foam tendency and water hardness sensitivity had to be ensured and, furthermore, it had to be ensured that no odor nuisance occurred due to the ingredients contained in such agents.

• a) ein oder mehrere Ammoniumsalze von Fettsäuren mit der allgemeinen Formel (I)
  
  in der n ₌ 1 oder 2 bedeuten; R^l, R², R³ und R⁴ gleich oder verschieden sein können und für Wasserstoff, unverzweigte oder verzweigte Alkylreste mit 1 bis 6 C-Atomen, Hydroxyalkylenreste mit 1 bis 6 C-Atomen oder Aminoalkylenreste mit 1 bis 8 C-Atomen stehen und R⁵ für unverzweigte und/oder verzweigte Alkylreste mit 6 bis 10 C-Atomen steht, in Mengen von 10 bis 90 Gew.-%, bezogen auf das Gesamtgewicht der Mischung, und
• b) ein oder mehrere Polyolfettsäuren und/oder deren Salze der allgemeinen Formel (11)
  
  in der R6 für einen geradkettigen oder verzweigten Alkyl- oder Alkylenrest mit 1 bis 19 C-Atomen und R7 für einen aus einer Di- oder Polyhydroxyverbindung durch Abspaltung einer Hydroxylgruppe entstandenen organischen Rest steht, M¢ = H⊕, Na⊕, K^¢ oder ein Ammoniumion [R1R2R3R4N ]ⁿ⁺ wie in Formel (I) bedeutet und m ganze Zahlen im Bereich von 0 bis 18 bedeutet, in Mengen von 10 bis 90 Gew.-%, bezogen auf das Gesamtgewicht der Mischung, enthalten.

The invention relates to water-soluble mixtures for corrosion inhibition, the

• a) one or more ammonium salts of fatty acids with the general formula (I)
  
  in which n ₌ 1 or 2; R ¹ , R ² , R ³ and R ^{4 may be the} same or different and represent hydrogen, unbranched or branched alkyl radicals having 1 to 6 C atoms, hydroxyalkylene radicals having 1 to 6 C atoms or aminoalkylene radicals having 1 to 8 C atoms and R ^{5 represents} unbranched and / or branched alkyl radicals having 6 to 10 carbon atoms, in amounts of 10 to 90% by weight, based on the total weight of the mixture, and
• b) one or more polyol fatty acids and / or their salts of the general formula (11)
  
  in which R6 is a straight-chain or branched alkyl or alkylene radical having 1 to 19 carbon atoms and R7 is an organic radical formed from a di- or polyhydroxy compound by splitting off a hydroxyl group, M ¢ = H⊕, Na⊕, K ^¢ or an ammonium ion [R1R2R3R4N] ^{n +} as in formula (I) and m means integers in the range from 0 to 18, in amounts of 10 to 90% by weight, based on the total weight of the mixture.

• R^{6 -} CH = CH - (CH₂)_m - COOY (III)
  in der R⁶ und m die obigen Bedeutungen haben und Y Wasserstoff ist, oder deren Derivate, in denen Y den Rest eines ein- oder mehrwertigen Alkohols wie z.B. des Glycerins oder Methanols bedeutet, nach an sich bekannten Methoden epoxidiert, das erhaltene Epoxid nach an sich bekannten Methoden mit einer Di- oder Polyhydroxyverbindung der allgemeinen Formel (IV)
• R70H (IV)
  in der R⁷ für einen aus einer Di- oder Polyhydroxyverbindung durch Abspaltung einer Hydroxylgruppe entstandenen organischen Rest steht, umsetzt, gegebenenfalls die Derivate der erhaltenen Polyolfettsäure mit Basen der allgemeinen Formel M⊕OH⊖, in der M^e die oben genannten Bedeutungen hat, oder mit einer Säure verseift und die erhaltene Polyolfettsäure und/oder deren Salze der allgemeinen Formel (11) und gegebenenfalls weitere Polyolfettsäuren der genannten allgemeinen Formel mit einem oder mehreren Ammoniumsalzen von Fettsäuren mit der obigen allgemeinen Formel (I) im Gewichtsverhältnis 10 : 1 bis 1 : 10 sowie gegebenenfalls mit Wasser mischt.

The invention also relates to a process for the preparation of such mixtures, which is characterized in that unsaturated fatty acids of the general formula (III)

• R ^{6 -} CH = CH - (CH ₂ ) _m - COOY (III)
  in which R ⁶ and m have the above meanings and Y is hydrogen, or their derivatives in which Y is the residue of a mono- or polyhydric alcohol, such as glycerol or methanol, epoxidized according to methods known per se, the epoxide obtained according to known methods with a di- or polyhydroxy compound of the general formula (IV)
• R70H (IV)
  in which R ^{7 represents} an organic radical formed from a di- or polyhydroxy compound by splitting off a hydroxyl group, optionally reacting the derivatives of the polyol fatty acid obtained with bases of the general formula M⊕OH⊖, in which M ^{e has} the abovementioned meanings, or saponified with an acid and the polyol fatty acid and / or its salts of the general formula (11) and optionally further polyol fatty acids of the general formula mentioned with one or more ammonium salts of fatty acids with the general formula (I) above in a weight ratio of 10: 1 to 1: 10 and optionally mixed with water.

The invention also relates to the use of such water-soluble mixtures of fatty acid-ammonium salts and polyol fatty acids and / or their salts for corrosion inhibition in drilling oils, cutting oils, rolling oils, sleeping oils, solutions for metal cleaning, coolants and lubricants.

The water-soluble mixtures for corrosion inhibition according to the invention contain one or more ammonium salts of fatty acids of the above-mentioned general formula (I) as one component. In (I), n can mean 1 or 2 and one or more of the radicals R ¹ , R ² , R ³ and R ^{4 can be the} same or all radicals can be different from one another. They can stand for hydrogen and unbranched or branched alkyl radicals with 1 to 6 carbon atoms, hydroxyalkylene radicals with 1 to 6 carbon atoms in the alkylene radical or - with n = 2 - for aminoalkylene radicals with 1 to 8 carbon atoms. The alkyl radicals are therefore the radicals methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl, and also n-pentyl or n-hexyl and their branched isomers. Suitable hydroxyalkylene radicals are hydroxymethylene or hydroxyethylene radicals or their higher homologues with 3 to 6 carbon atoms in the alkylene radical. Aminoalkylene radicals which can be mentioned are correspondingly aminoomethylene, aminoethylene or aminopropylene radicals or their higher homologs with 4 to 8 C atoms or corresponding aminoalkylene radicals which are substituted on the N atom by C _1-3 alkyl groups.

Preference is given to compounds (I) with n = 1 in which one radical in the ammonium cation represents an alkyl radical having 1 to 6 carbon atoms and the remaining radicals are hydrogen, or compounds (I) in which two of these radicals represent an alkyl group 3 or 4 carbon atoms and the other two radicals represent hydrogen. Also preferred are compounds (I) with n = 2, in which one of the residues in the ammonium cation denotes an aminoalkylene residue as defined above and which therefore have two cationic N atoms; one of the other radicals stands for an alkyl radical with 1 to 3 carbon atoms, the remaining two radicals for hydrogen.

Ammonium salts (1) with ammonium cations, in which two radicals represent an n-butyl group and the other two radicals are hydrogen, and ammonium salts (I) in which the ammonium cation for [N, N-dimethylpropylenediamine-1, 3] ²⁺ stands.

The radical R5 in the general formula (I) represents unbranched and / or branched alkyl radicals having 6 to 10 carbon atoms. Suitable radicals R5 are in particular i-heptyl, i / n-octyl, i-nonyl or n-decyl. The ammonium salts (I) thus originate, for example, from caprylic acid, isononanoic acid or capric acid.

Mixtures of ammonium salts of two fatty acids, each having the general formula (I), are preferred as the ammonium salt component. Mixtures of two ammonium salts in a weight ratio of 1: 1 have proven particularly useful. Mixtures of ammonium salts (I), which result from the neutralization of a mixture of 50% capric acid and 50% capric acid with amines having 1 to 8 carbon atoms, such as, for example, with di-n-butylamine, have proven particularly advantageous. N, N-dimethylpropylenediamine- (1,3) or 2-amino-2-methylpropanol-1.

The water-soluble mixtures according to the invention contain one or more of the ammonium salts of fatty acids with the general formula (I) in amounts of 10 to 90% by weight, based on the total weight of the mixtures according to the invention. Quantities in the range from 10 to 50% by weight are to be regarded as preferred.

One or more polyol fatty acids and / or their salts of the general formula (11) are present as a further component in the water-soluble mixtures according to the invention. In the general formula (11), R6 represents a straight-chain or branched alkyl or alkylene radical having 1 to 19 carbon atoms. So there are the residues methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl and n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n -Decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl or n-nonadecyl and the branched isomers of the alkylene or alkyl radicals mentioned in Question. Alkyl radicals whose carbon number is in the range from 8 to 15 are preferred.

In the general formula (II) mentioned, m stands for integers in the range from 0 to 18, preferably in the range from 8 to 14. In practice, compounds of the general formula (II) in which the radical R ^{6 is} n-octyl and m represents 7.

• Ethylenglykol
• Glycerin
• Diglycerin
• Propylenglykol
• Diethylenglykol
• Dipropylenglykol
• Trimethylolethan
• Trimethylolpropan
• Neopentylglykol
• Pentaerythrit
• Dipentaerythrit
• Sorbit
• Sorbitan
• Diethanolamin
• Triethanolamin

In the general formula (II), R ⁷ stands for an organic radical which has formally arisen from a di- or polyhydroxy compound by splitting off a hydroxyl group. The compounds from the following group have proven particularly useful as di- or polyhydroxy compounds:

• Ethylene glycol
• Glycerin
• Diglycerin
• Propylene glycol
• Diethylene glycol
• Dipropylene glycol
• Trimethylolethane
• Trimethylolpropane
• Neopentyl glycol
• Pentaerythritol
• Dipentaerythritol
• Sorbitol
• Sorbitan
• Diethanolamine
• Triethanolamine

Polyethylene glycol

Polypropylenglykol

Propylenoxid-Ethylenoxid-Blockpolymere, d.h. Verbindungen der Formel

mit

und Ethylenoxid-Propylenoxid-Blockpolymere, d.h. Verbindungen der Formel

mit

Polypropylene glycol

Propylene oxide-ethylene oxide block polymers, ie compounds of the formula

With

and ethylene oxide-propylene oxide block polymers, ie compounds of the formula

With

The alkoxy radical R ⁷ O- in the general formula (II) is formed in the course of the process according to the invention described below, in which di- or polyhydroxy compounds of the formula (IV) are added to an epoxide of an unsaturated carboxylic acid (III).

The products of the formula (11) also include mixtures of compounds in which two or more Fatty acid molecules are linked together by a di- or polyhydroxy compound of the formula (IV).

Instead of the polyol fatty acids of the general formula (II) given above, in which M⊕ each represents H⊕, their water-soluble salts can also be used. As such, alkali metal salts, for example sodium and / or potassium salts, in which M⊕ is Na ^¢ or K⊕, are preferred. It is also advantageous to use salts (II) in which M⊕ represents an ammonium cation [R ⁱ R ² R ³ R4N] ^{n +} , where R ¹ , R2, R3, and R4 and n have the meanings given above.

One or more polyol fatty acids or their salts of the general formula (II) can be contained in the water-soluble mixtures for corrosion inhibition according to the invention. The total amounts of the compounds (II) mentioned are in the range from 10 to 90% by weight, based on the total weight of the mixtures, preferably in the range from 50 to 90% by weight.

• R^{6 -} CH = CH - (CH₂)_m - COOY (III)
  in der R6 und m die obigen Bedeutungen haben und Y Wasserstoff ist, oder deren Derivate, in denen Y den Rest eines ein- oder mehrwertigen Alkohols wie z.B. des Glycerins oder Methanols bedeutet, nach an sich bekannten Methoden epoxidiert. Dies kann beispielsweise unter Verwendung von Peroxycarbonsäuren nach an sich bekannten Methoden geschehen. Die Epoxydation liefert dabei Epoxide, in denen der Oxiranring die Position im Molekül einnimmt, die im Edukt durch die mit der Doppelbindung verbundenen Kohlenstoffatome vorgegeben ist. Das erhaltene Epoxid wird dann nach ebenfalls an sich bekannten Methoden mit einer Di- oder Polyhydroxyverbindung der allgemeinen Formel (IV)
• R70H (IV)
  umgesetzt, in der R⁷ die obigen Bedeutungen hat. Dies kann beispielsweise dadurch geschehen, daß die Epoxide unter Säurekatalyse mit einem Überschuß der genannten Di- oder Polynydroxyverbindung (IV) umgesetzt werden, wobei sich der Oxiranring öffnet und der Epoxidsauerstoff zur Hydroxygruppe wird und das benachbarte Kohlenstoffatom den Alkoxyrest -OR⁷ der zur Ringöffnung verwendeten Di- oder Polyhydroxyverbindung trägt. Gegebenenfalls wird bei der Umsetzung mit der Di- oder Polyhydroxyverbindung (IV) auch die freie Carboxylgruppe verestert bzw. die mit dem Rest Y veresterte endständige Gruppe -COOY in der allgemeinen Formel (III) umgeestert. Gewünschtenfalls werden dann die Derivate der erhaltenen Polyolfettsäuren, deren Carboxylgruppe regelmäßig verestert ist, mit Basen der allgemeinen Formel M⊕OH, in der M⊕ die oben genannten Bedeutungen von Na⊕, K⊕, [RiR²R³R4N]ⁿ⁺ usw. hat, oder mit einer Säure verseift. Dabei werden dann die freien Polyolfettsäuren der allgemeinen Formel (II), in der M⊕ für das Wasserstoffion steht, oder deren Salze der Formel (11), in der M⊕ für ein Alkalimetallkation wie Na^¢ oder K⊕ oder für ein Ammoniumion [R¹R²R³R⁴N]ⁿ⁺ mit den oben angegebenen Bedeutungen für R^l, R², R³ und R⁴ sowie n steht, gebildet.

The process for producing such water-soluble mixtures for corrosion inhibition can be described as known per se. The polyol fatty acids of the general formula (II) are essentially prepared by the process described in DE-OS 33 18 596. This consists in that unsaturated fatty acids of the general formula (III)

• R ^{6 -} CH = CH - (CH ₂ ) _m - COOY (III)
  in which R6 and m have the meanings given above and Y is hydrogen, or their derivatives in which Y is the residue of a mono- or polyhydric alcohol, such as glycerol or methanol, epoxidized by methods known per se. This can be done, for example, using peroxycarboxylic acids according to methods known per se. Epoxidation provides epoxides in which the oxirane ring occupies the position in the molecule that is specified in the educt by the carbon atoms connected to the double bond. The epoxide obtained is then, using methods which are also known per se, using a di- or polyhydroxy compound of the general formula (IV)
• R70H (IV)
  implemented in which R ^{7 has} the above meanings. This can be done, for example, by reacting the epoxides with an excess of the di- or polynydroxy compound (IV) mentioned under acid catalysis, the oxirane ring opening and the epoxy oxygen becoming the hydroxyl group and the neighboring carbon atom using the alkoxy radical -OR ⁷ or for opening the ring Di- or polyhydroxy compound carries. If appropriate, the free carboxyl group is also esterified in the reaction with the di- or polyhydroxy compound (IV) or the terminal group -COOY esterified with the radical Y is transesterified in the general formula (III). If desired, the derivatives of the polyol fatty acids obtained, the carboxyl group of which is regularly esterified, with bases of the general formula M⊕OH, in which M⊕ has the abovementioned meanings of Na⊕, K⊕, [RiR ² R ³ R4N] ^{n +} etc. , or saponified with an acid. The free polyol fatty acids of the general formula (II), in which M⊕ represents the hydrogen ion, or their salts of formula (11), in which M⊕ represents an alkali metal cation such as Na ^¢ or K⊕ or an ammonium ion [R ¹ R ² R ³ R ⁴ N] ^{n +} with the meanings given above for R ¹ , R ² , R ³ and R ⁴ and n is formed.

The term unsaturated fatty acids of the general formula (III) or of the di- or polyhydroxy compounds of the formula (IV) also includes unsaturated fatty acids with more than one double bond or di- or polyhydroxy compounds, such as those generally obtained from industrially available oils and fats, such as Soybean oil, linseed oil, rape oil etc. are available.

The polyol fatty acid or its salts of the general formula (II) obtained in this way is then, if desired, combined with further polyol fatty acids of the general formula mentioned and with one or more ammonium salts of fatty acids with the general formula (I) in a weight ratio of 10: 1 to 1:10, preferably 3: 1, and optionally mixed with water.

The water-soluble mixtures according to the invention obtained in this way are outstandingly suitable as agents for inhibiting corrosion in drilling oils, cutting oils, rolling oils, grinding oils, solutions for metal cleaning, coolants and lubricants. It is surprising in the use of such mixtures that polyol fatty acids and their salts of the general formula (11) as such have no corrosion-inhibiting properties. However, in combination with the ammonium salts of fatty acids with the general formula (I), the compounds mentioned have a strong synergistic effect in that they significantly increase their ability to inhibit corrosion on metal surfaces. For example, it is possible to reduce the concentration of the ammonium salts of fatty acids, which as such - as known from the prior art - have corrosion-inhibiting properties by up to 50%, without any deterioration in the corrosion protection. It is further to be regarded as an advantage of the water-soluble mixtures according to the invention that they have a pronounced lack of foam and, moreover, the odor nuisance objected to when the ammonium salts of fatty acids of the general formula (I) are used alone does not occur. In addition, the mixtures according to the invention are also extremely soluble in extremely hard water. This property is also significantly improved in mixtures which, in addition to one or more ammonium salts of fatty acids with the general formula (I), also contain one or more polyol fatty acids and / or their salts of the general formula (II).

The invention is illustrated by the examples below.

example 1

Preparation of the potassium salt of a polyol fatty acid of the general formula (11) (R6 = n-octyl, m ₌ 7, R ⁷ = 2,2-bis (hydroxymethyl-) butyl, M⊕ = K⊕)

670 g of 1.1.1-tris (hydroxymethyl) propane (trimethylolpropane), 1.5 g of sulfuric acid and 1175 g of epoxidized soybean oil were heated to 100 _° C. with stirring for 1.5 hours. After cooling to 50 _° C., an aqueous solution of 247 g KOH in 623 g water was added and the reaction mixture was heated at 100 _° C. for a further 3 hours. This gave an 80% aqueous solution of the potassium salt of polyol fatty acid (II) (R ⁶ = n-octyl, m = 7, R ⁷ = 2,2-bis (-hydroxymethyl) butyl, M ⁹ = K⊕).

Example 2

Preparation of the potassium salt of polyol fatty acid (11) with R ⁶ = n-octyl, m = 7, R7 ₌ 2.3-dihydroxypropyl, M⊕ = K ^® . ^-

920 g of glycerol, 3.5 g of sulfuric acid and 1758 g of epoxidized oleic acid methyl ester were heated to 100 _° C. for 2 hours with stirring. After cooling to 50 _° C., the heterogeneous reaction mixture was neutralized with 30% methanolic sodium methylate solution, the glycerol phase was separated and the remaining phase was freed from approx. 200 g of volatile components at 200 _° C. and a pressure of 0.01 mbar. The distillation residue consisted of a light yellow oil.

712 g of this oil was heated with a solution of 80 g NaOH in 453 g water at 100 _° C for 3 hours. After cooling to 70 _° C., the reaction mixture was adjusted to a pH of 2 with sulfuric acid, the aqueous phase was separated off and the organic phase was washed with water heated to 60 _° C. In this way, a polyol fatty acid (II) (R6 = n-octyl, m = 7, R7 = 2,3-dihydroxypropyl, M⊕ = H⊕) is obtained. 69.3 g of this polyol fatty acid are neutralized with 16.8 g of a 50% aqueous potassium hydroxide solution and diluted with 63.9 g of deionized water.

Example 3

Preparation of a corrosion inhibiting mixture.

53 g of the neutralization product of a mixture of 50% by weight of carpylic acid and 50% by weight of capric acid with di-n-butylamine were mixed with 100 g of the product from Example 1 and 60 g of water.

Example 4

Production of a further corrosion-inhibiting mixture.

50 g of the neutralization product of a mixture of 50% by weight of carpylic acid and 50% by weight of capric acid with di-n-butylamine were mixed with 150 g of the product from Example 2.

Example 5

250 g of trimethylolpropane, 0.56 g of concentrated sulfuric acid and 439 g of epoxidized soybean oil were heated to 100 _° C. with stirring for 1.5 hours. After cooling to 90 _° C, the reaction mixture was mixed with 75 ml of a 50% aqueous sodium hydroxide solution and saponified at 100 _° C for 3 h. After cooling again to 90 ° C., the reaction mixture was adjusted to pH 2 with 500 g of 30% strength aqueous phosphoric acid, the aqueous phase was separated off and the remaining organic phase was washed with 2 × 40 ml of water. The 622 g of polyol fatty acid obtained in this way were neutralized with 131 g of diethanoiamine. The product was then diluted with 653.6 g of deionized water.

Example 6

150 g of the substance produced according to Example 5 were mixed with 50 g of the neutralizate of 50% by weight of caprylic acid and 50% by weight of capric acid with di-n-butylamine.

Example 7

Corrosion test according to DIN 51360.

The mixtures from Examples 3 and 4 were given in concentrations of 0.5 and 1 wt .-%, given as ammonium salt-polyol fatty acid mixture in the total amount of water, in water of different hardness, completely dissolved and in the corrosion test according to DIN 51360 on the Corrosion-inhibiting effect checked. The results are shown in Table 1 below.

As a comparison, the commercially available amine salt of a 1: 1 mixture of caprylic acid and capric acid with di-n-butylamine, hereinafter referred to as "comparative substance", was used. Its concentration in the application solution was 1 or 2% by weight.

• 0 = keine Korrosion,
• 1 = Spuren von Korrosion,
• 2 = leichte Korrosion,
• 3 = mäßige Korrosion,
• 4 = starke Korrosion.

The evaluation of the corrosion on the tested sheets was based on the following scale:

• 0 = no corrosion,
• 1 = traces of corrosion,
• 2 = slight corrosion,
• 3 = moderate corrosion,
• 4 = severe corrosion.

Result:

At a concentration of 1% by weight, the results for corrosion inhibition in the products of Examples 3 and 4 according to the invention are significantly better than in the comparison substance, even in very hard water. Results of the corrosion inhibition that are comparable with the comparison substance are achieved with a reduced use amount of the mixtures according to the invention.

Example 8 Foam test.

Test method: 50 ml of a test solution containing 3% of the mixtures according to the invention were shaken ten times in a 100 ml measuring cylinder and the foam volume in ml and the foam disintegration time in min were measured. The results are shown in Table 2 below. The neutralization product of a 1: 1 mixture of caprylic acid and capric acid with di-n-butylamine was again used as the reference substance.

Result:

Both the product according to Example 4 and that according to Example 3 shows a foam breakdown which is surprisingly rapid for amine soaps in comparison with the comparison substance. The polyol fatty acid in the mixture according to the invention therefore has a synergistic effect on the foam decomposition in the products mentioned.

In addition, it was found that the products according to Examples 3 and 4 are clearly superior to the comparison product in terms of odor nuisance: While the comparison product smells extremely unpleasant, no odor nuisance can be found in the products according to Examples 3 and 4.

Claims (24)

1. Water-soluble corrosion-inhibiting mixtures containing

a) one or more ammnonium salts of fatty acids corresponding to the following general formula

in which n ₌ 1 or 2 while Rl, R2, R3 and R4 may be the same or different and represent hydrogen, unbranched or branched C_1-6 alkyl groups, C_1-6, hydroxyalkylene groups or C_1-8 aminoalkylene groups and R5 represents unbranched and/or branched C_5-10 alkyl groups, in quantities of from 10 to 90% by weight, based on the mixture as a whole and

b) on or more polyol fatty acids and/or salts thereof corresponding to the following general formula

in which R6 is a straight-chain or branched C_1-19 alkyl or alkenylene group and R⁷ is an organic residue formed from a dihydroxy or polyhydroxy compound by elimination of a hydroxyl group, M⁹ = H⁹, Na⊕, K⁹ or an ammonium ion [R¹R²R³R⁴N]ⁿ+, as in formula (I), and m is an integer of from 0 to 18, in quantities of from 10 to 90% by weight, based on the total weight of the mixture.

2. Water-soluble mixtures as claimed in claim 1 containing one or more ammonium salts of fatty acids corresponding to general formula (I), in which n = 1 and one of the substituents R1 to R⁴ is a C_1-6 alkyl group while the other substituents represent hydrogen.

3. Water-soluble mixtures as claimed in claim 1 containing one or more ammonium salts of fatty acids corresponding to general formula (I), in which n = 1 and two of the substituents R¹ to R4 represent C₃ or C₄ alkyl groups while the other substituents represent hydrogen.

4. Water-soluble mixtures as claimed in claim 3, containing one or more ammonium salts of fatty acids corresponding to general formula (I), in which n = 1 and two of the substituents R¹ to R4 represent n-butyl.

5. Water-soluble mixures as claimed in claim 1, containing one or more ammonium salts of fatty acids corresponding to general formula (I), in which n = 2 and the ammonium cation [R¹R²R³R⁴N]ⁿ+ represents [N,N-dimethyl-1,3-propylenediamine]²⁺,

6. Water-soluble mixtures as claimed in claims 1 to 5 containing one or more ammonium salts of fatty acids corresponding to general formula (I), in which R5 represents i-heptyl, i/n-octyl, i-nonyl or n-decyl.

7. Water-soluble mixtures as claimed in claims 1 to 6 containing two ammonium salts each of a fatty acid corresponding to general formula (I) in a ratio by weight of 1:1.

8. Water-soluble mixtures as claimed in claim 7 containing a 1:1 mixture of a neutralization product of caprylic acid and di-n-butylamine and also capric acid and di-n-butylamine.

9. Mixtures as claimed in claims 1 to 8 containing one or more ammonium salts of fatty acids corresponding to general formula (I) in quantities of from 10 to 50% by weight, based on the total weight of the mixture.

10. Water-soluble mixtures as claimed in claim 1 containing one or more polyol fatty acids and/or salts thereof corresponding to general formula (II) in which R6 is a straight-chain C_8-15 alkyl group.

11. Water-soluble mixtures as claimed in claim 1 containing one or more polyol fatty acids and/or salts thereof corresponding to general formula (II), in which m = 8 to 14.

12. Water-soluble mixtures as claimed in claims 10 and 11 containing one or more polyol fatty acids and/or salts thereof corresponding to general formula (II), in which R⁶ is n-octyl and m is the number 7.

13. Water-soluble mixtures as claimed in claim 1 containing one or more polyol fatty acids and/or salts thereof corresponding to general formula (II) in which R7 is an organic residue formed by elimination of a hydroxyl group from one of the following compounds: ethylene glycol, glycerol, diglycerol, propylene glycol, diethylene glycol, dipropylene glycol, trimethylol ethane, trimethylol propane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, diethanolamine, triethanolamine, polyethylene glycol

(H-(OCH₂CH₂-)_nOH with n = 1-10),

polypropylene glycol

with n = 1-10),

propylene oxide-ethylene oxide block polymers, i.e. compounds corresponding to the formula

with x+ y = 2-10 and ethylene oxide-propylene oxide block polymers, i.e. compounds corresponding to the formula

with x+ y = 2-10.

14. Water-soluble mixtures as claimed in claim 1 containing one or more polyol fatty acids and/or salts thereof corresponding to general formula (II) in quantities of from 50 to 90% by weight, based on the total weight of the mixture.

15. A process for the preparation of water-soluble corrosion-inhibiting mixtures containing one or more ammonium salts of fatty acids corresponding to the following general formula

in which n = 1 or 2 while R^l, R2, R³ and R4 may be the same or different and represent hydrogen, unbranched or branched C_1-6 alkyl groups, C_1-6 hydroxyalkylene groups or C_l-₈ aminoalkylene groups and R⁵ represents unbranched C_5-10 alkyl groups, in quantities of from 10 to 90% by weight, based on the total weight of the mixture and one or more polyol fatty acids and/or salts thereof corresponding to the following general formula

in which R⁶ is a straight-chain or branched C_1-19 alkyl or alkenylene group and R⁷ is an organic residue formed from a dihydroxy or polyhydroxy compound by elimination of a hydroxyl group, M⊕ = H⊕, Na^D, K⊕ or an ammonium ion [R¹R²R3R4N]ⁿ+, as in formula (I), and m is an integer of from 0 to 18, in quantities of from 10 to 90% by weight, based on the total weight of the mixture, characterized in that

a) unsaturated fatty acids corresponding to the following general formula

in which R⁶ and mare as defined above and Y is hydrogen, or derivatives thereof, in which Y is the residue of a monohydric or polyhydric alcohol, such as glycerol or methanol for example, are epoxidized by methods known per se,

b) the epoxide obtained is reacted by methods known per se with a dihydroxy or polyhydroxy compound corresponding to the following general formula

in which R7 represents an organic residue formed from a dihydroxy or polyhydroxy compound by elimination of a hydroxyl group,

c) optionally, the derivatives of the polyol fatty acid obtained are saponified with bases corresponding to the following general formula M⊕OH⊕, in which M⊕ is as defined above, or with an acid and d) the polyol fatty acid obtained and/or its salts corresponding to general formula (II) and, optionally, other polyol fatty acids corresponding to the above general formula are mixed with one or more ammonium salts of fatty acids corresponding to general formula (I) above, in which R¹, R2, R³, R4, R5 and n are as defined above, in a ratio by weight of from 10:1 to 1:10.

16. A process as claimed in claim 15, characterized in that oleic acid is used as the fatty acid corresponding to general formula (III).

17. A process as claimed in claims 15 and 16, characterized in that a compound from the group comprising ethylene glycol, glycerol, diglycerol, propylene glycol, diethylene glycol, dipropylene glycol, trimethylol ethane, trimethylol propane, neopentyl glycol, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, diethanolamine, triethanolamine, polyethylene glycol, polypropylene glycol and also propylene oxide-ethylene oxide block polymers and ethylene oxide-propylene oxide block polymers is used as the dihydroxy or polyhydroxy compound corresponding to general formula (IV).

18. A process as claimed in claims 15 to 17, characterized in that mixtures of ammonium salts of several fatty acids are used as the ammonium salt component.

19. A process as claimed in claim 18, characterized in that a mixture of the neutralization product of caproic acid with di-n-butylamine and capric acid with di-n-butyl amine in a ratio by weight of 1:1 is used as the ammonium salt component.

20. A process as claimed in claim 18, characterized in that a mixture of the neutralization product of caproic acid eith N,N-dimethyl-1,3-propylenediamine and capric acid with N,N-dimethyl-1,3-propylenediamine in a ratio by weight of 1:1 is used as the ammonium salt component.

21. A process as claimed in claims 15 to 20, characterized in that one or more ammonium salts of fatty acids corresponding to general formula (I) and one or more polyol fatty acids and/or salts thereof corresponding to general formula (II) are mixed with one another in a ratio by weight of 1:3 and water is optionally added.

23. The use of the water-soluble mixtures claimed in claims 1 to 14 for inhibiting corrosion in drilling oils, cutting oils, rolling oils, grinding oils, metal-cleaning solutions, coolants and lubricants.