EP2446003A1

EP2446003A1 - Polyalkylene glycol-based ether pyrrolidone carboxylic acids, and concentrates for the production of synthetic cooling lubricants containing the same

Info

Publication number: EP2446003A1
Application number: EP10724279A
Authority: EP
Inventors: Rainer Kupfer; Carsten Cohrs; Alexander Rösch
Original assignee: Clariant Finance BVI Ltd
Current assignee: Clariant International Ltd
Priority date: 2009-06-25
Filing date: 2010-05-19
Publication date: 2012-05-02
Also published as: JP2012530730A; CN102395660A; CN102395660B; BRPI1011781A2; WO2010149252A1; DE102009030412A1; US20120088705A1; JP5706405B2

Abstract

The invention relates to ether pyrrolidone carboxylic acids of formula (1), wherein R¹ represents a C₁-C₆-hydrocarbon group containing 1 to 4 oxy groups, R² represents H, CH₃, CH₂CH₃, (A-O) represents a (poly)alkylene glycol unit containing one or more C₂-C₄-alkoxy groups or a mixture of several C₂-C₄-alkoxy groups, wherein at least one alkoxy group is a butoxy or propoxy group, M represents hydrogen, alkali metal, alkaline earth metal, or an ammonium group, y is 1 or 2, and x is 1, 2, 3, or 4.

Description

Polyalkylene glycol based Etherpyrrolidoncarbonsäuren and concentrates for the production of synthetic coolants containing them.

The present invention relates to polyalkylene glycol-based etherpyrrolidonecarboxylic acids and concentrates for the production of synthetic cooling lubricants containing these etherpyrrolidonecarboxylic acids as lubricants.

A water-based concentrate for producing synthetic coolants typically contains the following components (described, for example, BT Mang, W. Dressel: "Lubricants and Lubrication", Wiley-VCH, Weinheim, 2001, Chapter 14, or JP Byer's "Metalworking Fluids", Taylor & Francis, 2006, p. 127 ff.):

(1) water 40 - 70%

(2) Lubricant 10 - 30%

(3) Corrosion Inhibitor 1 - 20%

(4) pH adjusting agent (eg alkanolamine) 1 - 30%

(5) EP / AW additives 0 - 10%

(6) Defoamer 0 - 2%

(7) Biocides 0 - 5%

(In percentages by weight)

The pH is typically in alkaline, usually pH> 8. Increasing the pH contributes to corrosion protection. decisive

Significance comes after the above composition to the anti-corrosion and lubricants.

These synthetic coolants are used in a variety of applications, particularly as abrasive and cutting fluids, and are manufactured at the point of use by dilution of water-containing coolant concentrates. The additives used today already have very good properties, nonetheless, the users of cooling lubricants always expect further cost reductions, which can only be achieved by the use of ever smaller amounts of very effective additive components.

It was therefore an object of the present invention to find lubricants for use as constituents of cooling lubricant concentrates which, compared to the prior art, achieve comparable lubricating effects at significantly lower use concentrations.

Very often used in water-soluble cooling lubricant concentrates lubricants are polyalkylene glycols (T. Mang, W. Dressel: "Lubricants and Lubrication", Wiley-VCH, Weinheim, 2001, p 378), by sequential or random polymerization of alkylene oxides, preferably ethylene oxide and The mode of action of these lubricants is based on "hydrodynamic lubrication". The polyalkylene glycols have a cloud point, d. H. at a certain temperature, the polymers become insoluble in water. When this temperature is reached by the heat released when grinding or cutting metal, the polymers exit the solution and form a thin film of lubricant between the metal and the tool. Due to this property, however, there is also a disadvantage: the polyglycols leave behind sticky residues, especially when older grinding and cutting fluids after long use have a high lime soap content and electrolyte content which lowers the cloud point.

WO-00/53701 describes carboxyl-terminated polyalkylene glycols as lubricants. The carboxyl groups are introduced either by reaction of a polyalkylene glycol with anhydrides in a simple condensation reaction or by formation of an ether carboxylic acid by reaction of the polyalkylene glycols with monochloroacetic acid salt. After neutralization by the

Adjusting the pH to alkaline, these lubricants have no or very high cloud points, but still reach the starting point Polylalkylene glycols comparable lubricating values. As an advantage, a reduced oxygen demand during disposal is indicated.

However, the esters produced by reaction with the anhydrides are very limited in their lifetime by the hydrolysis occurring under the alkaline conditions, so that very quickly only the polyalkylene glycols are present again. A disadvantage of the ether carboxylic acids is the waste produced in the production of at least 4 moles of sodium chloride per mole of difunctional polyalkylene glycol and the low space-time yield in the production, which leads to high overall costs. Another problem is the achievement of a complete implementation. If the polyalkylene glycol itself is not water-soluble, for. As a polypropylene glycol, residues of the free glycol lead to an undesirable turbidity or two-phase of the concentrate.

Etherpyrrolidonecarboxylic acids (hereinafter also "EPC") and their preparation are known in the art. Thus, for example, US Pat. Nos. 4,304,690, 4,298,708 and 4,235,811 describe the preparation of etherpyrrolidonecarboxylic acids based on fatty alcohol (poly) etheramines and their use in detergents and as catalyst for the preparation of polyurethane foams. These derived from fatty alcohols and their alkoxylates Pyrrolidoncarbonsäuren are oil-soluble, water-dispersible and can be used after neutralization in emulsifiable cooling lubricant concentrates as an emulsifier and corrosion inhibitor.

GB-A-1 323 061 claims hydraulic fluids containing pyrrolidonecarboxylic acids, which may also be polyalkylene glycol based etherpyrrolidone mono- and dicarboxylic acids. GB-A-1 323 061, however, describes only etherpyrrolidonecarboxylic acids derived from (poly) ethylene glycol amines, namely only the short-chain polyamine H 163 (9-hydroxy-4,7-dioxanonanamine) and its monoethanolamine derivative. These EPCs are used as corrosion inhibitors in hydraulic fluids. Another use described as the corrosion inhibitor in acidic cleaners. A lubricating effect is not taught. It has now been found that etherpyrrolidonecarboxylic acids of the formula 1 which, in addition to ethylene glycol and also propylene glycol units or in particular only propylene glycol units, are particularly effective lubricants in alkaline cooling lubricants. The effect is particularly pronounced when the etherpyrrolidonecarboxylic acids contain long polyalkylene glycol, in particular polypropyleneglycol, units, ie have a high molecular weight. These etherpyrrolidonecarboxylic acids can replace polyalkylene glycols and other prior art lubricants in concentrates for the production of synthetic (water-soluble) coolants, with much lower levels

Use concentrations must be used. The preparation of these etherpyrrolidonecarboxylic acids can be carried out analogously to the fatty alcohol-etherpyrrolidonecarboxylic acids by reacting itaconic acids with the polyetheramines. These polyetheramines are under the trade names polyetheramines (BASF) or Jeffamine ^® (Huntsman) partly commercially available or can be obtained with acrylonitrile and subsequent hydrogenation of the nitrile either by aminolysis of suitable polyalkylene glycols with ammonia or by reaction of polyalkylene glycols.

The invention thus provides etherpyrrolidonecarboxylic acids of the formula (1)

wherein

R ^{1 is} a Ci-C ₆ hydrocarbon group with 1-4 oxy groups

RH, CH ₃ , CH ₂ CH ₃

(AO) a (poly) alkylene glycol unit which has one or more C ₂ -C ₄ -

Alkoxy group (s) or a mixture of several C ₂ -C ₄ alkoxy groups, wherein at least one alkoxy group is a butoxy or propoxy group M is hydrogen, alkali metal, alkaline earth metal or an ammonium group y is 1 or 2 x 1, 2, 3 or 4.

Another object of the invention are concentrates for the production of synthetic coolants containing Etherpyrrolidoncarbonsäuren of formula (1) and the use of these concentrates for the production of synthetic coolants.

The polyalkylene glycol unit (AO) in formula (1) is one or a series of a plurality of C ₂ -C ₄ alkylene oxide units which may be different from each other. The different units may be arranged in random order or arranged sequentially (in blocks). When (AO) represents a single alkoxy group, (AO) represents a propoxy or butoxy group. If (AO) is more than one alkoxy group, (AO) contains at least one propoxy group or at least one butoxy group. These polyalkylene glycol units are formed in the first step of preparing the etherpyrrolidonecarboxylic acids by alkoxylating a hydroxyl group of a starting alcohol with one or more C ₂ -C ₄ -alkylene oxides to give a

Polyalkylene glycol, wherein the alkoxylation with several alkylene oxides either with a mixture of alkylene oxides or can be carried out sequentially. According to the invention, however, one of the alkylene oxides must be different from ethylene oxide.

In a preferred embodiment, the polyalkylene glycol units (A-O) contain sequentially arranged alkoxy groups. In a further preferred embodiment, the proportion of propoxy and / or butoxy groups is more than 20 mol%, in particular more than 50 mol%. In a particularly preferred embodiment, these are pure polypropylene glycol units.

The group - (AO) - represents in a preferred embodiment a poly (oxyalkylene) group of the formula (2)

wherein I is a number 0 to 200, m is a number from 0 to 200, n is a number from 0 to 200, where l + n is at least equal to 1.

I preferably represents a number from 1 to 10. m preferably represents a number from 20 to 50. n preferably represents a number from 1 to 10.

In a further preferred embodiment, I is zero, m is a number from 1 to 50, in particular 5 to 25, and n is 1 to 200, in particular 2 to 25.

In a further preferred embodiment, I and m are zero, and n is 1 to 50, in particular 2 to 30.

The number of alkoxy groups contained in the (AO) units of the etherpyrrolidonecarboxylic acids of the present invention is best defined by the molecular weight of the polyalkylene glycol groups. Thus, the number average molecular weight of the polyalkylene glycol group is generally at least 75 g / mol, preferably greater than 200 g / mol, particularly preferably 1,000-10,000 g / mol. The number-average molecular weight of the polyalkylene glycol group can be determined, for example, by gel permeation chromatography (GPC) on the unit R ¹ - [(AO) -H] _X. The effectiveness of the etherpyrrolidonecarboxylic acids according to the invention increases with the molecular weight of the polyalkylene glycols used as intermediates. The molecular weight is However, limited by the onset of insolubility in particular of a high proportion of propoxy- or butoxy-containing, high molecular weight etherpyrrolidonecarboxylic acids at pH> 7.

R ¹ is a radical obtained by the formal abstraction of the hydroxyl hydrogen atom from a mono-, di-, tri-or tetravalent alcohol comprising 1 to 7 carbon atoms. Preferably, this alcohol comprises 2 to 6 carbon atoms. Furthermore, R ^{1 is} preferably an aliphatic group. By formal abstraction is meant herein that the hydroxyl hydrogen atom is omitted. Starting from methanol CH ₃ OH, R ^{1 is} thus CH ₃ O, starting from ethylene glycol HO-CH ₂ -CH ₂ -OH R ^{1 is} either 0-CH ₂ -CH ₂ -OH or 0-CH ₂ -CH ₂ -O. The single oxygen atom -O is referred to herein as the oxy group. The number of oxy groups equals x. The number of oxy groups may be equal to or less than the number of OH groups of dihydric, trihydric or tetrahydric alcohols. Preferred alcohols are monoalcohols of the formula R ³ -OH with R ³ = C 1 -C ₄ , that is to say methanol, ethanol, n-propanol, n-butanol, isopropanol, isobutanol and tert-butanol. Also suitable are diols of the formula OH-R ⁴ -OH, with R ⁴ = C ₂ -C ₆ -alkylene, for example ethylene glycol, 1, 2 and 1, 3-propylene glycol, butanediol, hexanediol, neopentyl glycol, triols such as glycerol or trimethylolpropane and tetraols such as pentaerythrol.

In a preferred embodiment, the group R ¹ = CH ₃ O-, in a further preferred embodiment is a difunctional group, especially ethylene glycol and 1, 2-propylene glycol.

In the industrial production does not necessarily start from the starting unit R ¹ H, the starting alcohol may already contain one or more alkoxy groups, which are then further alkoxylated. Suitable starting alcohols are thus therefore methyl glycol, methyl diglycol, methyltriglycol, butylglycol, butyldiglycol, butyltriglycol, diethylene glycol, triethylene glycol, tetraethylene glycol, low molecular weight polyalkylene glycols, dipropylene glycol, tripropylene glycol, butylpropylene glycol, butyldipropylene glycol and low molecular weight polypropylene glycols. y and R ² are defined by the way in which the polyalkylene glycols are converted to the polyalkylene glycol etheramines. If the etheramine is formed by aminolysis of a polyalkylene glycol, y = 1 and R ² results from the end group of the polyalkylene glycol, that is, can be hydrogen, a methyl or ethyl group. When the etheramine was prepared by addition of acrylonitrile followed by hydrogenation, y = 2 and R ² is hydrogen. In a preferred embodiment, y = 1 and R ² = CH ₃ . In order to avoid problems in the use of the finished etherpyrrolidonecarboxylic acids (a poor water solubility at pH> 7) in the implementation of the polyalkylene glycols to the

Polyalkylene glycol etheramines a high degree of conversion is preferred, it is at least 95%, preferably 97%, more preferably> 99%.

A number of ether amines with different alkoxy groups, molecular weights and functionalities are commercially available for example under the name Jeffamine ^® or polyether amines.

The number x can be 1 to 4 and indicates the number of amino groups. If the etheramine bears an amino group, x = 1, it carries two, x = 2, and so on.

The reaction of the amine functions with itaconic acid gives rise to the pyrrolidonecarboxylic acid units. By using an excess of itaconic acid lower carboxylic acid contents can be achieved, but it sometimes comes to the formation of polyamides. The by-products are also less soluble, so that a high degree of conversion is preferred. Particular preference is given to a degree of conversion> 99%. Of equal importance is an efficient ring closure to the pyrrolidone, since the intermediate secondary amine poses regulatory problems in end use in some countries, especially Germany. It is therefore preferred to a low amine content of <1 wt .-% paid attention, particularly preferably a residual amine content <0.5 wt .-% is desired. As a particular advantage of the process is to highlight that each step is an addition step or condensation step, that is, all raw materials remain in the product (with the exception of water), so that no waste.

In a further preferred form, all functional groups of the

Converted into Pyrrolidoncarbonsäuregruppen so that x reflects the number of functional groups of the alcohol.

The resulting Etherpyrrolidoncarbonsäuren can be used for the production of cooling lubricant concentrates, which are diluted before use with water to the finished cooling lubricants. Typical dilution ratios are 1: 1-1: 100, preferably between 1:25 and 1:10 parts of concentrate to water. Compared to the lubricants known from the prior art smaller amounts are needed to comparable lubricating effects, measured z. B. on a Reichert Reibverschlusswaage to achieve. Since the etherpyrrolidonecarboxylic acids according to the invention have no cloud point at the typical pH values of a synthetic metalworking fluid, no disturbing residues remain on the workpieces or tools and the liquids have lime soaps and so on because of their high stability

Electrolytes have a long life. The concentration in the concentrate can be from 0.1 to 60% by weight, preferably from 1 to 25% by weight, more preferably from 5 to 15% by weight, and is chosen such that a sufficient lubricating effect is achieved in the application z. B. can be determined on the Reichert-Reibverschlusswaage. The etherpyrrolidonecarboxylic acids themselves need not be soluble in distilled water, it is sufficient or even preferred if they become soluble at pH> 7 by the use of neutralizing agent.

In addition to water as solvent, these concentrates contain the etherpyrrolidonecarboxylic acids according to the invention as lubricants and a neutralizing agent for adjusting the pH which, after dilution to the final working concentration, is between 7 and 11, preferably between 8 and 10 and more preferably between 8.5 and 9.5 , Neutralizers suitable for this purpose are amines of the formula (3)

NR ⁵ R ⁶ R ⁷ (3)

wherein

R ⁵ , R ⁶ and R ^{7 are} independently hydrogen or a

Hydrocarbon radical having 1 to 100 carbon atoms.

In a first preferred embodiment, R ⁵ and / or R ⁶ and / or R ⁷ independently of one another represent an aliphatic radical. This preferably has 1 to 24, more preferably 2 to 18 and especially 3 to 6 C atoms. The aliphatic radical may be linear, branched or cyclic. It can still be saturated or unsaturated. Preferably, the aliphatic radical is saturated. The aliphatic group may have substituents such as hydroxyl, Ci -C ₅ alkoxy- -alkyl, cyano, nitrile, nitro and / or C ₅ -C ₂ o-wear aryl groups such as phenyl. The C ₅ -C ₂ o-aryl radicals may in turn optionally substituted with halogen atoms, halogenated alkyl groups, -C ₂ o alkyl, C ₂ -C ₂ o-alkenyl, hydroxyl, -C ₅ alkoxy such as methoxy, amide , Cyano, nitrile, and / or nitro groups. In a particularly preferred embodiment, R ⁵ and / or R ⁶ and / or R ⁷ independently of one another are hydrogen, a C ₁ -C ₆ -alkyl, C ₂ -C ₆ -alkenyl or C ₃ -C ₆ -cycloalkyl radical and especially an alkyl radical with 1, 2, or 3 C atoms. These radicals can carry up to three substituents. Particularly preferred aliphatic radicals R ⁵ and / or R ⁶ and / or R ⁷ are hydrogen, methyl, ethyl, hydroxyethyl, n-propyl, isopropyl, hydroxypropyl, n-butyl, isobutyl and tert-butyl, hydroxybutyl, n-hexyl, cyclohexyl, n-octyl, n-decyl, n-dodecyl, tridecyl, isotridecyl, tetradecyl, hexadecyl, octadecyl and methylphenyl.

In another preferred embodiment, R ⁵ and R ⁶ together with the nitrogen atom to which they are attached form a ring. This ring preferably has 4 or more, such as 4, 5, 6 or more ring members. Preferred further ring members are carbon, nitrogen, oxygen and sulfur atoms. The rings in turn may carry substituents such as alkyl radicals. Suitable ring structures are, for example, morpholinyl, pyrrolidinyl, piperidinyl, imidazolyl and azepanyl radicals. In a preferred embodiment, then R ^{7 is} H or an alkyl radical having 1 to 12 carbon atoms.

In a further preferred embodiment, R ^5, R ⁶ and / or R ⁷ are independently an optionally substituted C ₆ -C ₂ aryl group or an optionally substituted heteroaromatic group having 5 to 12 ring members.

In a further preferred embodiment, R ⁵ , R ⁶ and / or R ⁷ independently of one another represent an alkyl radical interrupted by heteroatoms. Particularly preferred heteroatoms are oxygen and nitrogen.

Thus, R ⁵ , R ⁶ and / or R ⁷ independently of one another preferably represent radicals of the formula (4)

- (R ^β -O) _a -R ⁹ (4)

wherein

R ^{8 is} an alkylene group having 2 to 6 carbon atoms and preferably 2 to

4 C atoms such as ethylene, propylene, butylene or mixtures thereof, R ^{9 is} hydrogen, a hydrocarbon radical having 1 to 24 C atoms or a group of the formula -R ⁸ -NR ¹⁰ R ¹¹ , a is a number between 2 and 50, preferably between 3 and 25 and in particular between 4 and 10 and

R ¹⁰ , R ¹¹ independently of one another represent hydrogen, an aliphatic radical having 1 to 24 C atoms and preferably 2 to 18 C atoms, an aryl group or heteroaryl group having 5 to 12 ring members, a poly (oxyalkylene) group having 1 to 50 Poly (oxyalkylene) units, wherein the polyoxyalkylene units of alkylene oxide units with 2 to 6 C atoms, or R ¹⁰ and R ¹¹ together with the nitrogen atom to which they are attached form a ring with 4, 5, 6 or more ring members stand.

Further preferred are R ⁵ ; R ⁶ and / or R ⁷ independently of one another represent radicals of the formula (5)

- [Ri2-N (Ri3)] _b - (Ri3) (5)

wherein

R ^{12 is} an alkylene group having 2 to 6 carbon atoms and preferably 2 to

4 C atoms such as ethylene, propylene or mixtures thereof, each R ^{13 is} independently hydrogen, an alkyl or hydroxyalkyl having up to 24 carbon atoms such as 2 bis

20 C atoms, a polyoxyalkylene radical - (R ⁸ -O) _p -R ⁹ , or a polyiminoalkylene radical - [R ¹² -N (R ¹³ )] _q - (R ¹³ ), where R ⁸ , R ⁹ , R ¹² and R ¹³ are as defined above and q and p are independently from 1 to 50 and b is a number from 1 to 20 and preferably from 2 to 10 such as three, four, five or six.

The radicals of the formula (5) preferably contain 1 to 50, in particular 2 to 20, nitrogen atoms.

Particularly preferred neutralizing agents are water-soluble alkylamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine and longer-chain mono-, di- and trialkylamines, provided that they are at least 1 wt .-%, preferably 1-5 wt .-% water-soluble , The alkyl chains can be branched here. Also suitable are oligoamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, their higher homologs and mixtures of these. Further suitable amines in this series are the alkylated, especially methylated, representatives of these oligoamines, such as N, N-dimethyldiethyleneamine, N, N-dimethylpropylamine and longer-chain and / or higher alkylated amines of the same construction principle. Particularly suitable according to the invention are alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, diglycolamine, triglycolamine and higher homologs, methyldiethanolamine, ethyldiethanolamine, propyldiethanolamine, butyldiethanolamine and longer-chain alkyldiethanolamines, where the alkyl radical may be cyclic and / or branched. Further suitable alkanolamines are dialkylethanolamines such as dimethylethanolamine, diethylethanolamine, dipropylethanolamine, dibutylethanolamine and longer-chain dialkylethanolamines, where the alkyl radical may also be branched or cyclic. Also within the meaning of the invention, aminopropanol, aminobutanol, aminopentanol and higher homologs, as well as the corresponding mono- and dimethylpropanolamines and longer-chain mono- and dialkylamino alcohols can be used. Last but not least, special amines such as 2-amino-2-methylpropanol (AMP), 2-aminopropanediol, 2-amino-2-ethylpropanediol, 2-aminobutanediol and other 2-aminoalkanols, aminoalkylamine alcohols, tris (hydroxylmethyl) aminomethane are suitable, as well as end-capped Representatives such as methylglycolamine, methyldiglycolamine and higher homologs, di (methylglycol) amine, di (methyldiglycol) amine and their higher homologs and the corresponding triamines and polyalkylene glycol amines (eg Jeffamine ^® ). Usually and in the context of the invention, mixtures of the abovementioned amines are used to adjust desired pH values. The concentration of these amines in the concentrate can be 1 to 60% by weight, preferably 10 to 30% by weight, more preferably 15 to 25% by weight, and is chosen so that the desired pH is obtained after dilution.

Nitrogen-containing neutralizing agents cause M to be an ammonium group. The term ammonium group means with respect to M that this group may also be substituted. The nature of the substituents arises from the nature of the nitrogenous neutralizing agents as described above.

Further suitable neutralizing agents are the oxides and hydroxides of the alkali and / or alkaline earth metals, such as. For example, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide and calcium oxide. If you still want a cloud point, z. B to achieve cloud point defoaming, a polyalkylene glycol can be added, but this is used in significantly smaller amounts than when used as a lubricant. Thus, the concentrate may contain at most 10% by weight, preferably 0.1-5% by weight, particularly preferably 0.5-1.5% by weight, of polyalkylene glycol.

Suitable polyalkylene glycols have the same basic structure as the polyalkylene glycols suitable as raw materials for the preparation of the etherpyrrolidonecarboxylic acids, but the quantitative ratio of the various alkoxy groups is chosen such that the desired cloud point is reached. In a preferred embodiment, these are EO-PO-EO block polymers, which themselves have a cloud point (1% in water) 25-90 ⁰ C, preferably 30 - 80 ⁰ C, in particular 30 - 60 ⁰ C.

According to the invention, the cooling lubricant concentrates furthermore contain water-soluble corrosion inhibitors in amounts of from 0.1 to 60% by weight, preferably from 5 to 25% by weight, particularly preferably from 10 to 20% by weight. Suitable corrosion inhibitors are benzenesulfonic acid amidocaproic acid, toluenesulfonic acid amidocaproic acid, benzenesulfonic acid (N-methyl) amidocaproic acid, toluenesulfonic acid (N-methyl) amidocaproic acid (all formula (6)), alkanoylamidocarboxylic acids, especially isononanoylamidocaproic acid (formula (7)) and triazine-2,4,6-tris (aminohexanoic acid) (formula (8)), or the alkali, alkaline earth and amine salts of the compounds of formulas (6) - (8).

a) Toluene or benzenesulfonamidocaproic acids (formula (6))

with R ¹⁴ , R ¹⁵ = H or CH ₃

b) Isononanoylamidocaproic acid (Formula (7))

c) Triazine trisaminohexanoic acid (Formula (8))

Other known and suitable corrosion inhibitors are linear or branched Ce- to Cβ-carboxylic acids such. Example, octanoic acid, 2-ethylhexanoic acid, n-nonanoic acid, n-decanoic acid, n-lsodekansäure, dicarboxylic acids such as succinic acid, adipic acid, maleic acid, citric acid, and long-chain dicarboxylic acids such as decanedioic, undecanedioic or dodecanedioic acid, the chains may be branched or cyclic, and polycarboxylic acids. Also suitable corrosion inhibitors are alkanesulfonic acid amides, alkanesulfonamidocarboxylic acids and Phtalsäurehalbamide. Furthermore, the salts of the compounds listed above can also be used.

A widely used inorganic corrosion inhibitor is boric acid and its salts, amides and esters.

If the salts of one of the abovementioned corrosion inhibitors are used, these are preferably salts which are formed by reaction of the free acids with a neutralizing agent which is contained in the hydraulic fluid. In certain applications, the use of EP / AW additives to reduce abrasion is required. According to the invention, the concentrates can be used as EP / AW additives, for example water-soluble phosphoric acid esters, their salts, but also water-insoluble phosphoric esters, which are converted by the neutralizing agents into their salts and become soluble. Suitable phosphoric acid esters are the mono- and diesters of ethanol, butanol, propanol, methanol, hexanol, octanol, iso-octanol, phenol and other higher alcohols, ethylene glycol, propylene glycol, butyl glycol, butyl diglycol and mixtures thereof, as well as the mono- and diesters of ethoxylated alcohols and their mixtures.

Other suitable EP / AW additives are water-soluble sulfur compounds such. For example, sulfides, disulfides, mercaptobenzothiazole, sulfurized acrylic acid, dithiobis (thiazoles), z. As dimercaptothiodiazole and its salts, dithiodicarboxylic acids, especially dithio (diarylcarboxylic acids) such. B. dithiodibenzoic acid and its salts.

The concentration of EP / AW additives is generally between 0.1 and 20% by weight, preferably between 1 and 10% by weight.

In addition to the described additives, the concentrates according to the invention also biocides, defoamers, water softeners or solubilizers, z. B. butyl glycol or butyl diglycol.

The preparation of the cooling lubricant concentrates can be done by simply mixing the additives in any order. To avoid highly viscous phases, however, it is advisable first to introduce the water and then to add the immediately water-soluble additives in any order. Subsequently, the neutralizing agents can be added and subsequently the additives which first become water-soluble by neutralization. The etherpyrrolidonecarboxylic acids can be added at any point. In a preferred embodiment, the etherpyrrolidonecarboxylic acids are not soluble in pure water, but only at pH values> 7. In these cases Preferably, the neutralizing agents are first dissolved in water and then added the Etherpyrrolidoncarbonsäuren.

For use as a cooling lubricant, the concentrates prepared in this way are diluted to water with distilled water or else other process water or tap water in a ratio of 1: 1 to 1: 100, generally between 1:25 and 1:10 parts of concentrate and used.

Examples

Examples 1-11: General procedure for the preparation of N-substituted 5-oxopyrrolidine-3-carboxylic acids

In a standard stirred apparatus 1 equivalent of amine are initially charged and heated with stirring to 50 ⁰ C. Then 1 equivalent of itaconic acid are added in portions and the reaction mixture heated slowly to 180 ⁰ C. During the progress of the reaction, 1 equivalent of water of reaction is distilled off.

The product obtained is characterized by acid number (SZ) and base nitrogen (bas-N).

Example 1: (comparison)

From 133 g of 3- (2-methoxyethoxy) propylamine and 130 g of itaconic acid, 240 g

5-Oxo [3- (2-methoxyethoxy) propyl] pyrrolidine-3-carboxylic acid with

SZ = 226.5 mg KOH / g and bas. N <0.1%.

Example 2: (comparison)

From 103 g of 4,7,10-trioxatridecane-1, 13-diamine and 65 g of itaconic acid were added 155 g

5-Oxo [4,7,10-trioxatridecane-1,13-di] -pyrrolidine-3-carboxylic acid with

SZ = 271, 4 mg KOH / g and bas-N <0.1%

Example 3: (comparison)

From 105 g of 2- (2-aminoethoxy) ethanol and 130 g of itaconic acid were added 210 g

5-Oxo [2-hydroxyethyl-ethoxy] -pyrrolidine-3-carboxylic acid with SZ = 174.3 mg KOH / g and bas. N <0.1%

Example 4:

From 230 g (1 mole) of polyetheramine D-230 ^® (Polypropylenglykoldiamin having an average molecular weight of 230 g / mol) and 260 g (2 mol) itaconic acid was 454 g of product with bas-N <0.1%, and acid number of 251 mg KOH / g obtained as a light yellow liquid.

Example 5: From 442 g (1 mole) of polyetheramine D-400 ^® (Polypropylenglykoldiamin having an average molecular weight of 400 g / mol) and 260 g (2 mol) itaconic acid was 665 g of product with bas-N <0.1% and SZ of 164 mg KOH / g as a light yellow liquid.

Example 6:

From 500 g (0.25 mol) of polyetheramine ^® D-2000 (polypropylene glycol diamine with an average molecular weight of 2,000 g / mol) and 65 g (0.5 mol) of itaconic acid was 546 g of product with bas.-N <0.1% and SZ of 52 mg KOH / g as a light yellow liquid.

Example 7:

From 514 g (0.25 mol) Jeffamine ^® M-2070

(Methylpoly (ethoxy) poly (propoxy) monoamine having an average molecular weight of about 2,000 g / mol) and 32.5 g (0.25 mol) of itaconic acid was 535 g of product with bas-N <0.1% and bp of 25.1 mg KOH / g as a yellow liquid.

Example 8:

From 611 g (1 mol) Jeffamine ^® ED-600 (PO-EO-PO block polymer based diamine having an average molecular weight of 600 g / mol) and 260 g (2 mol) itaconic acid was 835 g of product bas-N <0 , 1% and SZ of 130 mg KOH / g as a light yellow liquid. Example 9:

From 518 g (0.25 mol) of Jeffamine ^® ED-2003 (PO-EO-PO block polymer based diamine having an average molecular weight of 2,000 g / mol) and 65 g (0.5 mol) itaconic acid was 573 g of product with bas -N <0.1% and SZ of 47 mg KOH / g as a yellow liquid.

Example 10:

From 98 g (0.2 mole) of polyetheramine ^® T 403 (trimethylolpropane tris (polypropylene glycol) amine with an average molecular weight of 440 g / mol) and 78 g (0.6 mol) itaconic acid was 160 g of product with bas-N < 0.1% and SZ of 198 mg KOH / g as a yellow liquid.

Example 11:

From 226 g (0.04 mol) of polyetheramine T 5000 ^® (Glyceryltris (polypropylene glycol) amine with an average molecular weight of 5,000 g / mol) and 15.6 g (0.12 mol) itaconic acid was 230 g of product with bas-N < 0.1% and SZ of 27 mg KOH / g as a yellow liquid.

The etherpyrrolidonecarboxylic acids from Examples 1 to 11 were reacted with a double excess of triethanolamine to form the actual water-soluble lubricant, and in aqueous solution the behavior against hard water, the cloud point and the lubricity on the Reichert friction weighing scale (loading: 1.5 kg / travel 100 m / Steel rolls / results of the ground joint in mm ² ). As a comparison, the polyalkylene glycols Genapol ^® and Genapol PN30 ^® B from the prior art were measured. Examples 1-3 correspond to the prior art of GB-A-1 323 061, ie ether pyrrolidone carboxylic acids derived from (poly) ethylene glycol amines. For better readability, the term etherpyrrolidonecarboxylic acid has been abbreviated to EPC in the table. In cases where the cut mark was> 30 mm ² , no lower concentration was measured. Table 1: Properties and lubricating values of etherpyrrolidonecarboxylic acids

κ>

O

¹⁾ load 1, 5 kg, steel rollers, 100 m track, rotation speed 1, 6 m / s; Blank value water: 38 mm ²

The polyalkylene Genapol ^® B and PN30 have very good lubricating properties, but also the detrimental cloud point described on. Examples 1 - 3 show that low-molecular-weight etherpyrrolidonecarboxylic acids containing only PEG chains derived from ethylene oxide do not meet the requirements of a good lubricant, since the grinding marks are at least less than 10% in these Reichert measurements at a use concentration of 10% 20 mm ² should be.

Examples 4-11 show the advantageous absence of cloud point and comparable or superior lubricity of the invention

Etherpyrrolidoncarbonsäuren. In particular high molecular weight (Examples 6,7,9,11) representatives have improved lubricating effects. In one of the preferred embodiments described above are etherpyrrolidonecarboxylic acids with pure polypropylene chains (Examples 4 - 6, 10, 11), which have the best lubricating values in high molecular weight form, even at very low concentrations (Example 6.11).

The following examples illustrate the preparation of a cooling lubricant concentrate containing ether pyrrolidonecarboxylic acids and its use.

Example 12: Coolant Concentrate (comparison)

40 g of water are placed in a 250 ml beaker. With constant stirring, first 15 g of triethanolamine (neutralizing agent), then 20 g of isononanoylamidocaproic acid (corrosion inhibitor), 9 g of Genapol B and 1 g of Genapol PN30 are added. For clarification, 5 g of butyldiglycol are added.

Example 13: Coolant concentrate containing

Etherpyrrolidonecarboxylic acid from example 6 45 g of water are placed in a 250 ml beaker. With constant stirring, first 17 g of triethanolamine, then 20 g of isononanoyl-caproic acid and then 8 g of the ECS from Example 6 are added. Example 14: Cooling lubricant concentrate containing Etherpyrrolidoncarbonsäure from Example 6

In a 250 ml beaker 45 g of water are introduced. With constant stirring, first 15 g of triethanolamine and 2 g of monoethanolamine are added and then 12 g of isononanoylcaproic acid, 8 g of dithiodibenzoic acid (AW / EP additive) and finally 8 g of the ECS from Example 7 are added.

Example 15: Coolant concentrate containing

Etherpyrrolidonecarboxylic acid from Example 11 A 250 ml beaker is charged with 45 g of water. With constant stirring, first 17 g of triethanolamine, then 20 g of isononanoyl-caproic acid and then 8 g of the ECS from Example 11 are added.

Table 2 lists the performance data of synthetic coolants prepared from the concentrates of the present invention containing the most effective etherpyrrolidone carboxylic acids of Examples 6 and 11 and the prior art. The pHs were adjusted to 8.5 with traces of monoethanolamine.

Table 2: Coolants from concentrates

²⁾ load 1, 5 kg, steel rollers, 100 m travel, rotation speed 1, 6 m / s; Blank value water: 38 mm ²

Table 2 shows the effectiveness of the cooling lubricants produced from the ether carboxylic acids containing (Example 13 - 15) cooling lubricant concentrates compared to the prior art (Example 12). The ether carboxylic acids are used together with the neutralizing agent, corrosion inhibitors and optionally EP / AW additive (Example 14) in smaller amounts than the polyalkylene glycols (Genapol PN 30, Genapol B). Corrosion protection and stability against hard water are not affected.

Claims

claims

1. Etherpyrrolidonecarboxylic acids of the formula (1)

wherein

R ^{1 is} a CrC ₆ hydrocarbon group with 1-4 oxy groups

R ² H, CH ₃ , CH ₂ CH ₃ (AO) a (poly) alkylene glycol unit which has one or more C ₂ -C ₄ -

Alkoxy group (s) or a mixture of several C ₂ -C ₄ alkoxy groups, wherein at least one alkoxy group is a butoxy or propoxy group

M is hydrogen, alkali metal, alkaline earth metal or an ammonium group y is 1 or 2 x 1, 2, 3 or 4.

2. Etherpyrrolidoncarbonsäuren according to claim 1, wherein R ^{1 is} an aliphatic group.

3. Etherpyrrolidoncarbonsäuren according to claim 1 and / or 2, wherein R ^{1 contains} 2 to 6 carbon atoms.

4. Etherpyrrolidoncarbonsäuren according to one or more of claims 1 to 3, wherein (AO) is an alkoxy group having a number average molecular weight of more than 200 g / mol.

5. Etherpyrrolidoncarbonsäuren according to one or more of claims 1 to 4, wherein (A-O) is an alkoxy group which comprises more than 20 mol% of propoxy groups.

6. Etherpyrrolidoncarbonsäuren according to one or more of claims 1 to 5, wherein y = 1 and R ² = H, CH ₃ or CH ₂ CH ₃ .

7. Etherpyrrolidoncarbonsäuren according to one or more of claims 1 to 5, wherein y = 2 and R ² = H is.

8. A composition comprising at least one Etherpyrrolidoncarbonsäure according to one or more of claims 1 to 7, water and a neutralizing agent in an amount sufficient so that the pH of the composition is between 7 and 11.

A composition according to claim 8, which additionally contains 0.1-60% by weight of a water-soluble corrosion inhibitor.

10. The composition of claim 8 and / or 9, additionally containing 0.1 and 20 wt .-% of an EP / AW additive.

11. Use of an etherpyrrolidonecarboxylic acid according to one or more of claims 1 to 7 as a lubricant in cooling lubricants.