EP0249148A2 - 2-Hydroxydodecylmonoesters of dicarboxylic acids, their salts and their use as corrosion inhibitors in aqueous systems - Google Patents

2-Hydroxydodecylmonoesters of dicarboxylic acids, their salts and their use as corrosion inhibitors in aqueous systems Download PDF

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Publication number
EP0249148A2
EP0249148A2 EP87108076A EP87108076A EP0249148A2 EP 0249148 A2 EP0249148 A2 EP 0249148A2 EP 87108076 A EP87108076 A EP 87108076A EP 87108076 A EP87108076 A EP 87108076A EP 0249148 A2 EP0249148 A2 EP 0249148A2
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Prior art keywords
water
salts
use according
ppm
hydroxydodecyl
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EP87108076A
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German (de)
French (fr)
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EP0249148A3 (en
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Josef Dr. Penninger
Volker Dr. Wehle
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Henkel AG and Co KGaA
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Henkel AG and Co KGaA
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M129/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing oxygen
    • C10M129/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing oxygen having a carbon chain of less than 30 atoms
    • C10M129/68—Esters
    • C10M129/76—Esters containing free hydroxy or carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/12—Oxygen-containing compounds
    • C23F11/124—Carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
    • C10M2201/02—Water
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
    • C10M2207/28—Esters
    • C10M2207/287—Partial esters
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/12—Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives

Definitions

  • the invention relates to dicarboxylic acid mono- (2-hydroxydodecyl) esters, their salts and their use as a corrosion inhibitor in aqueous systems.
  • Water-bearing systems such as steam generation systems, heating systems, cooling water circuits and closed water supply systems are permanently exposed to the corrosive attack of the water circulating in them, which is primarily directed against the base materials of the respective systems, e.g. steel, brass, aluminum, zinc or galvanized steel.
  • the risk of corrosion is further increased by the fact that in such systems there are usually elevated temperatures and the circulating water contains constituents which also chemically promote the corrosive attack on the respective materials. Chemicals that prevent corrosion or prevent it completely have therefore long been added to the waters circulating in the systems mentioned as anti-corrosion agents. This has proven particularly useful in this context hang the use of phosphorus-containing compounds, for example phosphonic acids or inorganic phosphates, which are optionally combined with zinc salts. The effectiveness of these combinations has so far been entirely satisfactory.
  • Zinc salts are generally known to be extremely toxic to fish, which is why these types of water must never be allowed to get into the wastewater.
  • self-cleaning power of natural water is significantly inhibited even at zinc concentrations above 0.1 ppm.
  • the use of combinations of zinc salts with phosphonic acids or phosphates also generally leads to increased silting of the process water circulation system due to the precipitation of zinc hydroxide at higher pH values (pH greater than 8.0).
  • the object of the present invention was to provide corrosion inhibitors for aqueous systems which are effective, essentially phosphorus- and zinc-free, even at low concentrations, which are easily accessible in terms of production technology and which permanently or completely prevent the corrosion of numerous materials used in plant construction.
  • the compounds used should be environmentally neutral and meet the legal requirements applicable in this context, particularly with regard to their toxicity.
  • the invention therefore relates to dicarboxylic acid mono- (2-hydroxydodecyl) esters of the general formula (I) and their salts of the general formula (II) in which A for the residues - (CH2) 2-, - (CH2) 3-, and M represents an alkali metal or ammonium.
  • the general formulas (I) and (II) defined above thus comprise the following compounds: succinic acid mono- (2-hydroxydodecyl) ester, glutar acid mono- (2-hydroxydodecyl) esters, itaconic acid mono- (2-hydroxydodecyl) esters, phthalic acid mono- (2-hydroxydodecyl) esters or their salts, preferably their sodium, potassium or ammonium salts, and in particular their sodium salts.
  • the invention also relates to the use of dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their salts (II) in concentrations of 1 to 100 ppm as corrosion inhibitors in aqueous systems, if appropriate in the presence of further stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides.
  • the invention also relates to the use of dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their water-soluble salts (II) in combination with one or more complexing agents from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, citric acid, phosphoric acid esters of ethoxylated sugars and phosphonic acid or the water-soluble salts of these acids, in particular the sodium salts, optionally in the presence of further, known stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides as corrosion inhibitors in aqueous systems, the concentration of the mixture of (I) and / or (II) and the complexing agents in aqueous solution in the range from 1 to 100 ppm and the ratio of (I) and / or (II) to the complexing agents in the range between 5: 1 and 1: 5.
  • one or more complexing agents from the group
  • the high effectiveness of the compounds mentioned as corrosion inhibitors is all the more surprising as Dicarboxylic acid mono- (2-hydroxyalkyl) esters, in which the ester alkyl groups have less than 12 or more than 12 C atoms, and dicarboxylic acid monoalkyl esters, which have no hydroxyl group in the ester alkyl group, have an insignificant or no corrosion-inhibiting action in process water.
  • Dicarboxylic acid mono- (2-hydroxyalkyl) esters in which the ester alkyl groups have less than 12 or more than 12 C atoms
  • dicarboxylic acid monoalkyl esters which have no hydroxyl group in the ester alkyl group, have an insignificant or no corrosion-inhibiting action in process water.
  • Corrosion inhibitors according to the invention are primarily dicarboxylic acid mono- (2-hydroxydodecyl) esters of the formula (I) and their water-soluble salts of the general formula (II)
  • A represents the radicals - (CH2) 2-, - (CH2) 3-, and M for an alkali metal or ammonium, preferably for sodium, potassium or ammonium.
  • the resulting Salts (II) have good water solubility without exception.
  • the corrosion inhibitors to be used according to the invention are therefore the following compounds: Succinic acid mono- (2-hydroxydodecyl) esters, glutaric acid mono- (2-hydroxydodecyl) esters, itaconic acid mono- (2-hydroxydodecyl) esters, phthalic acid mono- (2-hydroxydodecyl) esters or their salts defined above.
  • Succinic acid mono- (2-hydroxydodecyl) esters glutaric acid mono- (2-hydroxydodecyl) esters
  • itaconic acid mono- (2-hydroxydodecyl) esters phthalic acid mono- (2-hydroxydodecyl) esters or their salts defined above.
  • phthalic acid mono- (2-hydroxydodecyl) esters or their salts are preferred.
  • the half esters (I) formed by esterification between the acid anhydride or the dicarboxylic acid and the alcoholic component can subsequently be neutralized by reaction with a base M-OH, salts (II) being formed in accordance with the above reaction scheme.
  • the dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and their salts (II), in which A and M have the meanings given above, are used individually or in any mixtures with one another as corrosion inhibitors.
  • the high, corrosion-inhibiting action of the esters (I) alone is remarkable and particularly advantageous for the use according to the invention, without any further addition.
  • the concentration of the dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) and / or its salts (II) is in the range from 1 to 100 g / m3, i.e. in the range of 1 to 100 ppm.
  • a preferred concentration range is 10 to 50 ppm of the compounds (I) and / or (II) mentioned.
  • the compounds (I) and / or (II) are used according to the invention as a corrosion inhibitor for metals
  • aqueous systems such as are found in water-carrying systems such as steam generating systems, heating systems, cooling water circuits and water supply systems.
  • the compounds mentioned can preferably be used in process water systems.
  • polyacrylates and / or copolymers of acrylic acid and / or methacrylic acid and / or their derivatives with an average molecular weight of 500 to 4000 and / or ethylene oxide-propylene oxide block copolymers with an average molecular weight of 500 to 3000 have proven to be stone protection and / or dispersants and an ethylene oxide to propylene oxide ratio of 10:90 to 30:70.
  • stone protection and dispersing agents are used in combination with dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their salts (II) in amounts of 1 to 50 g / m3 (1 to 50 ppm), preferably in amounts of 3 to 10 ppm.
  • the corrosion inhibitors (I) and / or (II) are used according to the invention, it may be advantageous to provide inhibitors for non-ferrous metals as further additives known per se for this purpose.
  • dicarboxylic acid mono- (2-hydroxydodecyl) esters and / or their water-soluble salts according to the invention 3-heptyl-5-amino-1,2,4-triazole, benzimidazole, benzotriazole and / or tolyltriazole are preferably dissolved in the process water as non-ferrous metal inhibitors.
  • the amount of non-ferrous metal inhibitors is in the range from 0.1 to 5 g / m3 (0.1 to 5 ppm).
  • microbicidal or biocidal substances may also be advantageous to add microbicidal or biocidal substances to the industrial water in amounts of 1 to 100 g / m3 (1 to 100 ppm).
  • such substances are in particular glutaraldehyde, glyoxal or alkyloligoamides, preferably in the form of a reaction product of dodecylpropylenediamine and ⁇ -caprolactam in a molar ratio of 1: 2.
  • the dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) or their water-soluble salts (II) used according to the invention as corrosion inhibitors for metals have the advantage over comparable compounds used as corrosion inhibitors or with regard to the chemical structure that they have completely different corrosion-inhibiting substances, for example in the way described above, are technically easy to manufacture and already at low concentrations in the aqueous in question Systems have an extremely high corrosion-inhibiting effect. This effect is largely independent of the pH. In addition, they have no detrimental, in particular no toxic, effect and can therefore be used without hesitation in water that is ultimately released into the environment from the systems mentioned. In comparison to phosphorus-containing corrosion-inhibiting agents, they also do not lead to eutrophication of the water.
  • esters of the formula (I) and / or their salts corresponds to the general formula (II), preferably the sodium salts, a particularly preferred and advantageous embodiment of the present invention, which is also significantly better than that of conventional complexing agents in terms of the corrosion-inhibiting activity.
  • the combination of for Corrosion inhibiting agents used complexing agents with the esters (I) of the present invention and / or their salts (II) leads to a significant improvement in corrosion protection.
  • a further preferred embodiment within the meaning of the present invention should therefore be considered to use dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) and / or its water-soluble salts (II) in combination with one or more complexing agents for inhibiting corrosion in aqueous systems.
  • the esters (I) and their water-soluble salts (II), of which the sodium salt is particularly preferred over the other alkali metal salts or the ammonium salt, can be used individually or in any mixtures with one another.
  • Complexing agents from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, citric acid, phosphoric acid esters of ethoxylated sugars and phosphonic acid or the water-soluble salts of these acids, in particular the sodium salts, are suitable for such preferred combinations.
  • phosphoric acid esters of ethoxylated sugars esters of such sugars are suitable which have a degree of ethoxylation of 1 to 10, preferably 1 to 5.
  • the sugars are selected from the group of sorbitol, mannitol, glucose and mixtures of two or three of these sugars in any proportion with one another.
  • phosphonic acids suitable for the purpose of complex formation can be used as phosphonic acids the, where phosphonic acids from the group 1-hydroxyethane-1,1-diphosphonic acid, aminotris- (methylenephosphonic acid) and 2-phosphonobutane-1.2.4-tricarboxylic acid and the water-soluble salts of such phosphonic acids are suitable. These can also be used individually or in any mixtures with one another.
  • the concentration of the combination of mono- (2-hydroxydodecyl) dicarboxylic acid (I) or its water-soluble salts (II) on the one hand and one or more complexing agents from the above-mentioned group on the other hand in the aqueous solution is in the range from 1 to 100 ppm, preferably in the range from 2 to 60 ppm.
  • the ratio of the components ester (I) and / or their salts (II) to complexing agents is in the range between 5: 1 and 1: 5, a range from 2: 1 to 1: 2 being particularly preferred.
  • the corrosion-inhibiting effect even when using such combinations, is largely independent of the pH, since the acid form of the esters, that is to say the compound (I.), Immediately changes in the acidic pH range, for example at a pH of 6.5 ), forms during alkaline pH values, for example at a pH of 8.2, the alkali metal or ammonium salts of the esters, that is to say the compounds (II), are present.
  • the combinations according to the invention of compounds (I) and / or (II) with one or more of the complexing agents mentioned can also be mixed with other additives customary in such systems without difficulty, with the result that, together with these, an additionally improved corrosion protection trains. Examples of such additives are stone protection agents and / or dispersants, non-ferrous metal inhibitors or biocides from the groups specified above.
  • the blank value was determined on sheets of the same quality after treatment with an aqueous solution without the inhibitor according to the invention.
  • test water used as the corrosive medium had the following analytical data: 8 ° dH (calcium hardness); 2 ° dH (magnesium hardness); 1 ° dH (carbonate hardness) and 500 ppm Cl ⁇ .
  • Table 1 below shows the results of the corrosion protection tests when using dicarboxylic acid mono- (2-hydroxydodecyl) esters (DHDE) or their sodium salts.
  • DHDE dicarboxylic acid mono- (2-hydroxydodecyl) esters
  • dicarboxylic acid mono- (2-hydroxydodecyl) esters (I), or their Na salts as corrosion inhibitors can provide significantly better corrosion protection in both weakly acidic and weakly basic environments than with the structurally similar compounds to DHDE - see experiments a to g.
  • the comparison compounds a to f are corresponding dicarboxylic acid monoesters with shorter or longer carbon chains in the ester alkyl groups; in the case of the comparative compound g, the ester alkyl group - with a chain length of 12 carbon atoms - has no hydroxyl group.
  • the corrosion inhibitors known from the prior art - see experiment h to k - better or comparable values are obtained, but when using the DHDE no phosphorus and no zinc get into the waste water and no precipitation occurs.
  • Example 2 Analogously to the procedure described in Example 1, a corresponding number of test sheets were treated in an aqueous solution which contained a combination of DHDE (I) or its sodium salt (II) and a complexing agent, which is mentioned in Table 3. The sheets were treated as described in Example 1 and the corrosion protection value of the combination used according to the invention, based on a blank value, was determined in accordance with the formula given in Example 1.
  • Example 2 Analogously to Example 2, in comparison to the combination of DHDE or its sodium salts and complexing agents, further corrosion inhibitors known per se, in some cases together with zinc salts, were tested with regard to their corrosion-inhibiting behavior. The results are shown in Table 4 below.

Abstract

Mono-2-(hydroxydodecyl) dicarboxylates of the general formula (I) …<IMAGE>… and salts thereof of the general formula (II) …<IMAGE>… …<??>in which A represents the radicals -(CH2)2-, -(CH2)3-, …<IMAGE>… and M represents an alkali metal or the ammonium group, and the use of compounds of this type alone or in combination with one or more complexing agents in concentrations from 1 to 100 ppm as corrosion inhibitors in aqueous systems, if appropriate in the presence of further scale prevention agents and/or dispersants and/or nonferrous metal inhibitors and/or microbicides which are known per se.

Description

Die Erfindung betrifft Dicarbonsäuremono-(2-hydroxy­dodecyl)ester, deren Salze und deren Verwendung als Korrosionsinhibitor in wässrigen Systemen.The invention relates to dicarboxylic acid mono- (2-hydroxydodecyl) esters, their salts and their use as a corrosion inhibitor in aqueous systems.

Wasserführende Anlagen, wie Dampferzeugungsanlagen, Heizsysteme, Kühlwasserkreisläufe und geschlossene Wasserleitungssysteme sind permanent dem korrosiven Angriff des in ihnen zirkulierenden Wassers ausge­setzt, der sich vorwiegend gegen unedle Werkstoffe der jeweiligen Systeme, beispielsweise Stahl, Messing, Aluminium, Zink oder verzinkten Stahl, richtet. Die Korrosionsgefahr wird noch dadurch erhöht, daß in der­artigen Anlagen meist erhöhte Temperaturen herrschen und das zirkulierende Wasser Bestandteile enthält, die den korrosiven Angriff auf die jeweiligen Werkstoffe auch chemisch fördern. Den in den genannten Systemen zirkulierenden Wässern werden daher seit langem als Korrosionsschutzmittel Chemikalien zugesetzt, die einer Korrosion vorbeugen oder sie völlig verhindern sollen. Besonders bewährt hat sich in diesem Zusammen­ hang die Verwendung von phosphorhaltigen Verbindungen, beispielsweise Phosphonsäuren oder anorganischen Phos­phaten, die gegebenenfalls mit Zinksalzen kombiniert werden. Die Wirksamkeit dieser Kombinationen konnte bisher vollauf befriedigen.Water-bearing systems such as steam generation systems, heating systems, cooling water circuits and closed water supply systems are permanently exposed to the corrosive attack of the water circulating in them, which is primarily directed against the base materials of the respective systems, e.g. steel, brass, aluminum, zinc or galvanized steel. The risk of corrosion is further increased by the fact that in such systems there are usually elevated temperatures and the circulating water contains constituents which also chemically promote the corrosive attack on the respective materials. Chemicals that prevent corrosion or prevent it completely have therefore long been added to the waters circulating in the systems mentioned as anti-corrosion agents. This has proven particularly useful in this context hang the use of phosphorus-containing compounds, for example phosphonic acids or inorganic phosphates, which are optionally combined with zinc salts. The effectiveness of these combinations has so far been entirely satisfactory.

Der in jüngster Zeit bekannt gewordene Zusammenhang zwischen hohem Phosphatgehalt natürlicher Gewässer und deren Eutrophierung, der sich auch in gesetzlichen Auflagen für die Bestandteile in Brauchwassersystemen wasserführender Anlagen niederschlug, führte zu der Forderung, daß derartige Brauchwässer weitgehend oder vollständig frei von phosphorhaltigen Verbindungen sein müssen. Die genannten Phosphonsäuren bzw. anor­ganischen Phosphate als korrosionsinhibierende Zusätze zu Brauchwasser haben, vom praktisch-technischen Standpunkt aus gesehen, außerdem den weiteren Nach­teil, daß innerhalb des Kühlsystems ebenfalls ein ver­stärktes biologisches Wachstum zu beobachten ist, zu dessen Inhibierung den Systemen zusätzlich Mikrobizide zugesetzt werden müssen.The recently known relationship between the high phosphate content of natural waters and their eutrophication, which was also reflected in legal requirements for the components in service water systems in water-bearing systems, led to the requirement that such service water must be largely or completely free of phosphorus-containing compounds. From the practical-technical point of view, the above-mentioned phosphonic acids or inorganic phosphates as corrosion-inhibiting additives to process water also have the further disadvantage that increased biological growth can also be observed within the cooling system, for the inhibition of which additional microbicides must be added to the systems .

Da in derartigen Brauchwasser-Umlaufsystemen mitunter auch Wässer größerer Härte eingesetzt werden, führt die Verwendung von phosphathaltigen Korrosionsinhibi­toren zusätzlich zur Bildung von Apatit oder apatit­ähnlichen Ablagerungen, die - wie der bekannte Kessel­stein - den Wärmeübergang außerordentlich erschweren und damit sehr schnell zu Betriebsstörungen führen. Außerdem sind derartige Ablagerungen - insbesondere in geschlossenen Kreisläufen - nur schwer zu entfernen.Since water of greater hardness is sometimes used in such process water circulation systems, the use of phosphate-containing corrosion inhibitors additionally leads to the formation of apatite or apatite-like deposits, which - like the well-known scale - make the heat transfer extremely difficult and thus very quickly lead to malfunctions. In addition, such deposits - particularly in closed circuits - are difficult to remove.

Probleme ergeben sich auch bei der Verwendung von Zinksalzen in Kombination mit derartigen phosphorhal­ tigen Korrosionsinhibitoren. Zinksalze sind im allge­meinen als ausgesprochen fischtoxisch bekannt, wes­wegen derartige Wässer keinesfalls in das Abwasser gelangen dürfen. Außerdem wird die Selbstreinigungs­kraft natürlicher Wässer bereits bei Zinkkonzentra­tionen oberhalb von 0,1 ppm deutlich gehemmt. Der Einsatz von Kombinationen von Zinksalzen mit Phosphon­säuren oder Phosphaten führt außerdem bei höheren pH-­Werten (pH größer 8,0) im allgemeinen zu verstärkter Verschlammung des Brauchwasser-Umlaufsystems aufgrund der Ausfällung von Zinkhydroxid.Problems also arise when using zinc salts in combination with such phosphorhal corrosion inhibitors. Zinc salts are generally known to be extremely toxic to fish, which is why these types of water must never be allowed to get into the wastewater. In addition, the self-cleaning power of natural water is significantly inhibited even at zinc concentrations above 0.1 ppm. The use of combinations of zinc salts with phosphonic acids or phosphates also generally leads to increased silting of the process water circulation system due to the precipitation of zinc hydroxide at higher pH values (pH greater than 8.0).

Die korrosionsinhibierende Wirkung von Dicarbonsäure­halbamiden und deren Derivaten, insbesondere von Bern­steinsäurehalbamiden, ist aus der DE-OS 33 00 874 be­kannt. Nachteilig an der Verwendung dieser Verbindun­gen ist jedoch deren unzureichende Wasserlöslichkeit.The corrosion-inhibiting effect of dicarboxylic acid halamides and their derivatives, in particular of succinic acid halamides, is known from DE-OS 33 00 874. However, the disadvantage of using these compounds is their insufficient water solubility.

Der vorliegenden Erfindung lag die Aufgabe zugrunde, schon in geringen Konzentrationen wirksame, im wesent­lichen Phosphor- und Zink-freie Korrosionsinhibitoren für wässrige Systeme zur Verfügung zu stellen, die herstellungstechnisch einfach zugänglich sind und die Korrosion zahlreicher im Anlagenbau verwendeter Werk­stoffe nachhaltig oder vollständig verhindern. Dabei sollten die verwendeten Verbindungen umweltneutral sein und die in diesem Zusammenhang geltenden gesetz­lichen Anforderungen, insbesondere hinsichtlich ihrer Toxizität, erfüllen.The object of the present invention was to provide corrosion inhibitors for aqueous systems which are effective, essentially phosphorus- and zinc-free, even at low concentrations, which are easily accessible in terms of production technology and which permanently or completely prevent the corrosion of numerous materials used in plant construction. The compounds used should be environmentally neutral and meet the legal requirements applicable in this context, particularly with regard to their toxicity.

Es wurde nun überraschend gefunden, daß spezielle Di­carbonsäuremono-(2-hydroxydodecyl)ester oder deren Salze - nämlich die entsprechenden Monoester der Bern­stein-, Glutar-, Itacon- und Phthalsäure - in der Lage sind, unter Einhaltung der ökologischen Forderungen, die Korrosion von Metallen in wässrigen Systemen, ins­besondere in Brauchwassersystemen, wirkungsvoll zu inhibieren.It has now surprisingly been found that special dicarboxylic acid mono- (2-hydroxydodecyl) esters or their salts - namely the corresponding monoesters of succinic, glutaric, itaconic and phthalic acids - are capable of this are effective in inhibiting the corrosion of metals in aqueous systems, especially in process water systems, in compliance with ecological requirements.

Die Erfindung betrifft daher Dicarbonsäuremono-(2-hy­droxydodecyl)ester der allgemeinen Formel (I)

Figure imgb0001
und deren Salze der allgemeinen Formel (II)
Figure imgb0002
 in welchen A für die Reste -(CH₂)₂-, -(CH₂)₃-,
Figure imgb0003
 und M für ein Alkalimetall oder Ammonium steht.The invention therefore relates to dicarboxylic acid mono- (2-hydroxydodecyl) esters of the general formula (I)
Figure imgb0001
 and their salts of the general formula (II)
Figure imgb0002
 in which A for the residues - (CH₂) ₂-, - (CH₂) ₃-,
Figure imgb0003
 and M represents an alkali metal or ammonium.

Die vorstehend definierten allgemeinen Formeln (I) und (II) umfassen somit die folgenden Verbindungen: Bernsteinsäuremono-(2-hydroxydodecyl)ester, Glutar­ säuremono-(2-hydroxydodecyl)ester, Itaconsäuremono-­(2-hydroxydodecyl)ester, Phthalsäuremono-(2-hydroxy­dodecyl)ester bzw. deren Salze, vorzugsweise deren Natrium-, Kalium- oder Ammoniumsalze, und insbesondere deren Natriumsalze.The general formulas (I) and (II) defined above thus comprise the following compounds: succinic acid mono- (2-hydroxydodecyl) ester, glutar acid mono- (2-hydroxydodecyl) esters, itaconic acid mono- (2-hydroxydodecyl) esters, phthalic acid mono- (2-hydroxydodecyl) esters or their salts, preferably their sodium, potassium or ammonium salts, and in particular their sodium salts.

Die Erfindung betrifft außerdem die Verwendung von Dicarbonsäuremono-(2-hydroxydodecyl)estern (I) und/­oder deren Salze (II) in Konzentrationen von 1 bis 100 ppm als Korrosionsinhibitoren in wässrigen Syste­men, gegebenenfalls in Gegenwart weiterer an sich be­kannter Steinschutz- und/oder Dispergiermittel und/­oder Buntmetallinhibitoren und/oder Mikrobizide.The invention also relates to the use of dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their salts (II) in concentrations of 1 to 100 ppm as corrosion inhibitors in aqueous systems, if appropriate in the presence of further stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides.

Die Erfindung betrifft auch die Verwendung von Dicar­bonsäuremono-(2-hydroxydodecyl)estern (I) und/oder deren wasserlöslichen Salzen (II) in Kombination mit einem oder mehreren Komplexbildnern aus der Gruppe Ethylendiamintetraessigsäure, Nitrilotriessigsäure, Citronensäure, Phosphorsäureester von ethoxylierten Zuckern sowie Phosphonsäure bzw. der wasserlöslichen Salze dieser Säuren, insbesondere der Natriumsalze, gegebenenfalls in Gegenwart weiterer, an sich bekann­ter Steinschutz- und/oder Dispergiermittel und/oder Buntmetallinhibitoren und/oder Mikrobizide als Korro­sionsinhibitoren in wässrigen Systemen, wobei die Kon­zentration des Gemisches aus (I) und/oder (II) und den Komplexbildnern in wässriger Lösung im Bereich von 1 bis 100 ppm und das Verhältnis von (I) und/oder (II) zu den Komplexbildnern im Bereich zwischen 5 : 1 und 1 : 5 liegt.The invention also relates to the use of dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their water-soluble salts (II) in combination with one or more complexing agents from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, citric acid, phosphoric acid esters of ethoxylated sugars and phosphonic acid or the water-soluble salts of these acids, in particular the sodium salts, optionally in the presence of further, known stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides as corrosion inhibitors in aqueous systems, the concentration of the mixture of (I) and / or (II) and the complexing agents in aqueous solution in the range from 1 to 100 ppm and the ratio of (I) and / or (II) to the complexing agents in the range between 5: 1 and 1: 5.

Die hohe Wirksamkeit der genannten Verbindungen als Korrosionsinhibitoren ist um so überraschender, als Dicarbonsäuremono-(2-hydroxyalkyl)ester, in denen die Ester-Alkylgruppen weniger als 12 oder mehr als 12 C-Atome aufweisen, sowie Dicarbonsäuremonoalkylester, die keine Hydroxylgruppe in der Ester-Alkylgruppe auf­weisen, eine unbedeutende oder gar keine korrosionsin­hibierende Wirkung in Brauchwasser-Umlaufsystemen auf­weisen.The high effectiveness of the compounds mentioned as corrosion inhibitors is all the more surprising as Dicarboxylic acid mono- (2-hydroxyalkyl) esters, in which the ester alkyl groups have less than 12 or more than 12 C atoms, and dicarboxylic acid monoalkyl esters, which have no hydroxyl group in the ester alkyl group, have an insignificant or no corrosion-inhibiting action in process water. Have circulation systems.

Erfindungsgemäße Korrosionsinhibitoren sind in erster Linie Dicarbonsäuremono-(2-hydroxydodecyl)ester der Formel (I)

Figure imgb0004
und deren wasserlösliche Salze der allgemeinen Formel (II)
Figure imgb0005
 In den allgemeinen Formeln (I) und (II) steht A für die Reste - (CH₂)₂-, -(CH₂)₃-,
Figure imgb0006
 und M für ein Alkalimetall oder Ammonium, vorzugsweise für Natrium, Kalium oder Ammonium. Die resultierenden Salze (II) weisen ausnahmslos eine gute Wasserlöslich­keit auf. Bevorzugte Salze der Formel (II) sind die Natriumsalze (M = Na).Corrosion inhibitors according to the invention are primarily dicarboxylic acid mono- (2-hydroxydodecyl) esters of the formula (I)
Figure imgb0004
 and their water-soluble salts of the general formula (II)
Figure imgb0005
 In the general formulas (I) and (II), A represents the radicals - (CH₂) ₂-, - (CH₂) ₃-,
Figure imgb0006
 and M for an alkali metal or ammonium, preferably for sodium, potassium or ammonium. The resulting Salts (II) have good water solubility without exception. Preferred salts of the formula (II) are the sodium salts (M = Na).

Bei den erfindungsgemäß zu verwendenden Korrisionsin­hibitoren handelt es sich somit um die folgenden Ver­bindungen:
Bernsteinsäuremono-(2-hydroxydodecyl)ester, Glutar­säuremono-(2-hydroxydodecyl)ester, Itaconsäuremono-­(2-hydroxydodecyl)ester, Phthalsäuremono-(2-hydroxy­dodecyl)ester bzw. um deren vorstehend definierte Sal­ze. Im Rahmen der erfindungsgemäßen Verwendung sind von diesen die entsprechenden Monoester der Itacon- und Glutarsäure bzw. deren Salze bevorzugt.The corrosion inhibitors to be used according to the invention are therefore the following compounds:
Succinic acid mono- (2-hydroxydodecyl) esters, glutaric acid mono- (2-hydroxydodecyl) esters, itaconic acid mono- (2-hydroxydodecyl) esters, phthalic acid mono- (2-hydroxydodecyl) esters or their salts defined above. Within the scope of the use according to the invention, the corresponding monoesters of itaconic and glutaric acid or their salts are preferred.

Die erfindungsgemäßen Verbindungen (I) können auf ein­fache Weise und in hohen Ausbeuten beispielsweise da­durch hergestellt werden, daß man

  • a) entweder die entsprechenden Dicarbonsäuren, d.h. die Bernstein-, Glutar-, Itacon- oder Phthalsäure, mit 1,2-Epoxydodecan
  • b) oder die Anhydride dieser Dicarbonsäuren mit 1,2-­Dodecandiol,
jeweils im Molverhältnis der Reaktionspartner von 1 : 1, gemäß dem nachfolgenden Reaktionsschema um­setzt:
Figure imgb0007
 The compounds (I) according to the invention can be prepared in a simple manner and in high yields, for example by
  • a) either the corresponding dicarboxylic acids, ie succinic, glutaric, itaconic or phthalic acid, with 1,2-epoxydodecane
  • b) or the anhydrides of these dicarboxylic acids with 1,2-dodecanediol,
in each case in a molar ratio of the reactants of 1: 1, according to the following reaction scheme:
Figure imgb0007

Die durch Veresterung zwischen dem Säureanhydrid bzw. der Dicarbonsäure und der alkoholischen Komponente entstandenen Halbester (I) können nachfolgend durch Umsetzung mit einer Base M-OH neutralisiert werden, wobei Salze (II) gemäß dem obigen Reaktionsschema ent­stehen.The half esters (I) formed by esterification between the acid anhydride or the dicarboxylic acid and the alcoholic component can subsequently be neutralized by reaction with a base M-OH, salts (II) being formed in accordance with the above reaction scheme.

Erfindungsgemäß werden die Dicarbonsäuremono-(2-hy­droxydodecyl)ester (I) und deren Salze (II), in denen A und M die oben angegebenen Bedeutungen haben, ein­zeln oder in beliebigen Mischungen miteinander als Korrosionsinhibitoren verwendet. Bemerkenswert und für die erfindungsgemäße Verwendung besonders vorteilhaft ist die hohe, korrosionsinhibierende Wirkung der Ester (I) allein, ohne jeden weiteren Zusatz.According to the invention, the dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and their salts (II), in which A and M have the meanings given above, are used individually or in any mixtures with one another as corrosion inhibitors. The high, corrosion-inhibiting action of the esters (I) alone is remarkable and particularly advantageous for the use according to the invention, without any further addition.

Bei der erfindungsgemäßen Verwendung als Korrosions­inhibitor in wässrigen Systemen liegt die Konzentra­tion der Dicarbonsäuremono-(2-hydroxydodecyl)ester (I) und/oder deren Salze (II) im Bereich von 1 bis 100 g/m³, d.h. im Bereich von 1 bis 100 ppm. Ein be­vorzugter Konzentrationsbereich liegt bei 10 bis 50 ppm der genannten Verbindungen (I) und/oder (II).When used according to the invention as a corrosion inhibitor in aqueous systems, the concentration of the dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) and / or its salts (II) is in the range from 1 to 100 g / m³, i.e. in the range of 1 to 100 ppm. A preferred concentration range is 10 to 50 ppm of the compounds (I) and / or (II) mentioned.

Bei der erfindungsgemäßen Verwendung der Verbindungen (I) und/oder (II) als Korrosionsinhibitor für Metalle liegen im wesentlichen wässrige Systeme vor, wie sie in wasserführenden Anlagen wie Dampferzeugungsanlagen, Heizsystemen, Kühlwasserkreisläufen und Wasserlei­tungssystemen vorgefunden werden. Bevorzugt lassen sich die genannten Verbindungen in Brauchwassersyste­men verwenden.When the compounds (I) and / or (II) are used according to the invention as a corrosion inhibitor for metals, there are essentially aqueous systems such as are found in water-carrying systems such as steam generating systems, heating systems, cooling water circuits and water supply systems. The compounds mentioned can preferably be used in process water systems.

In der Praxis spielt für das korrosive Verhalten eines Brauchwassers in hohem Maße eine Rolle, ob darin ab­lagerungsbildende Trübstoffe vorhanden sind oder durch Korrosion aus den wasserführenden Anlagenteilen ent­stehen können. Als solche sind z.B. Ausfällungen durch Wasserhärte (Calciumcarbonat), Ausfällungen durch Ton­substanzen und Eisenhydroxide anzusehen. Es liegt im Bestreben der erfindungsgemäßen Verwendung von Dicar­bonsäuremono-(2-hydroxydodecyl)estern und/oder deren Salzen, auch die Bildung von Ablagerungen aus derarti­gen Substanzen zu verhindern und damit das Verhalten des Brauchwassers im Sinne einer weiteren Inhibierung der Korrosion zu verbessern. Daher ist es im allgemei­nen vorteilhaft, dem Umlaufwasser außer Dicarbonsäure­mono-(2-hydroxydodecyl)estern (I) und/oder deren Sal­zen (II) weitere, für diesen Zweck an sich bekannte Steinschutz- und/oder Dispergiermittel und/oder Bunt­metallinhibitoren und/oder Mikrobizide zuzusetzen. Der Zusatz dieser Mittel ist für die Korrosionsinhibierung als solche nicht zwingend notwendig, kann aber das Verhalten des Brauchwassers im Umlaufsystem weiter verbessern.In practice, the corrosive behavior of process water plays a major role, whether there are sediment-forming turbid substances or whether corrosion can arise from the water-carrying parts of the system. As such, e.g. Precipitation due to water hardness (calcium carbonate), precipitation caused by clay substances and iron hydroxides. It is the aim of the use of dicarboxylic acid mono- (2-hydroxydodecyl) esters and / or their salts according to the invention to also prevent the formation of deposits from such substances and thus to improve the behavior of the process water in the sense of further inhibiting corrosion. It is therefore generally advantageous to add to the circulating water, in addition to dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their salts (II), other stone protection agents and / or dispersants known per se and / or non-ferrous metal inhibitors and / or Add microbicides. The addition of these agents is not absolutely necessary for corrosion inhibition as such, but can further improve the behavior of the process water in the circulation system.

Als Steinschutz- und/oder Dispergiermittel haben sich insbesondere Polyacrylate und/oder Copolymerisate von Acrylsäure und/oder Methacrylsäure und/oder ihren Deri­vaten mit einer mittleren Molekularmasse von 500 bis 4000 und/oder Ethylenoxid-Propylenoxid-Blockcopolymere mit einer mittleren Molekularmasse von 500 bis 3000 und einem Ethylenoxid-Propylenoxid-Verhältnis von 10 : 90 bis 30 : 70 erwiesen. Derartige Steinschutz- und Dispergiermittel werden in Kombination mit Dicar­bonsäuremono-(2-hydroxydodecyl)estern (I) und/oder deren Salzen (II) in Mengen von 1 bis 50 g/m³ (1 bis 50 ppm), vorzugsweise in Mengen von 3 bis 10 ppm, ver­wendet.In particular, polyacrylates and / or copolymers of acrylic acid and / or methacrylic acid and / or their derivatives with an average molecular weight of 500 to 4000 and / or ethylene oxide-propylene oxide block copolymers with an average molecular weight of 500 to 3000 have proven to be stone protection and / or dispersants and an ethylene oxide to propylene oxide ratio of 10:90 to 30:70. Such stone protection and dispersing agents are used in combination with dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their salts (II) in amounts of 1 to 50 g / m³ (1 to 50 ppm), preferably in amounts of 3 to 10 ppm.

Je nach Anwendungsbereich, in dem die Korrosionsin­hibitoren (I) und/oder (II) erfindungsgemäß verwendet werden, kann es vorteilhaft sein, als weitere, an sich für diesen Zweck bekannte Zusätze Inhibitoren für Buntmetalle vorzusehen. Bei der erfindungsgemäßen Ver­wendung von Dicarbonsäuremono-(2-hydroxydodecyl)estern und/oder deren wasserlöslichen Salzen sind als Bunt­metallinhibitoren bevorzugt 3-Heptyl-5-amino-1.2.4-­triazol, Benzimidazol, Benzotriazol und/oder Tolyl­triazol im Brauchwasser gelöst. Die Menge der Bunt­metallinhibitoren liegt dabei im Bereich von 0,1 bis 5 g/m³ (0,1 bis 5 ppm).Depending on the field of application in which the corrosion inhibitors (I) and / or (II) are used according to the invention, it may be advantageous to provide inhibitors for non-ferrous metals as further additives known per se for this purpose. When using dicarboxylic acid mono- (2-hydroxydodecyl) esters and / or their water-soluble salts according to the invention, 3-heptyl-5-amino-1,2,4-triazole, benzimidazole, benzotriazole and / or tolyltriazole are preferably dissolved in the process water as non-ferrous metal inhibitors. The amount of non-ferrous metal inhibitors is in the range from 0.1 to 5 g / m³ (0.1 to 5 ppm).

Es kann auch vorteilhaft sein, den Brauchwässern zu­sätzlich zu den oben genannten Komponenten noch mikro­bizide oder biozide Substanzen in Mengen von 1 bis 100 g/m³ (1 bis 100 ppm) zuzusetzen. Als solche Sub­stanzen, deren Verwendung aus dem Stand der Technik bekannt ist, kommen im vorliegenden Fall insbesondere Glutaraldehyd, Glyoxal oder Alkyloligoamide, vorzugs­weise in Form eines Umsetzungsproduktes von Dodecyl­propylendiamin und ε-Caprolactam im Molverhältnis 1 : 2 in Frage.It may also be advantageous to add microbicidal or biocidal substances to the industrial water in amounts of 1 to 100 g / m³ (1 to 100 ppm). In the present case, such substances, the use of which is known from the prior art, are in particular glutaraldehyde, glyoxal or alkyloligoamides, preferably in the form of a reaction product of dodecylpropylenediamine and ε-caprolactam in a molar ratio of 1: 2.

Die erfindungsgemäß als Korrosionsinhibitoren für Me­talle verwendeten Dicarbonsäuremono-(2-hydroxydode­cyl)ester (I) oder deren wasserlösliche Salze (II) haben gegenüber vergleichbaren, als Korrosionsinhibi­toren verwendeten Verbindungen oder auch hinsichtlich der chemischen Struktur völlig anderen korrosionsin­hibierenden Substanzen den Vorteil, daß sie, bei­spielsweise auf dem oben beschriebenen Wege, technisch leicht herstellbar sind und bereits bei niedrigen Kon­zentrationen in den in Frage kommenden wässrigen Systemen eine ausgesprochen hohe korrosionsinhibie­rende Wirkung entfalten. Diese Wirkung ist dabei in weiten Grenzen vom pH-Wert unabhängig. Außerdem haben sie keine nachteilige, insbesondere keine toxische Wirkung und können somit bedenkenlos auch in Wässern verwendet werden, die letztendlich aus den genannten Systemen in die Umwelt abgelassen werden. Im Vergleich zu phosphorhaltigen korrosionsinhibierenden Mitteln führen sie außerdem nicht zu einer Eutrophierung des Wassers. Ferner werden bei Verwendung der erfindungs­gemäßen Korrosionsinhibitoren keine Zinksalze benö­tigt, die das Abwasser im Hinblick auf deren Fisch­toxizität belasten. Zudem entfallen Abscheidungen von Zinkhydroxid, die bei Einsatz von Zinksalzen in Brauchwassersystemen üblicherweise auftreten. Ein wei­terer wesentlicher Vorteil ist darin zu sehen, daß sie ohne Schwierigkeiten mit an sich bekannten weiteren Zusätzen, wie Steinschutz- und Dispergiermitteln, Buntmetallinhibitoren oder Bioziden verwendet werden können und zusammen mit diesen ein zusätzlich verbes­sertes korrosionsinhibierendes Verhalten zeigen.The dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) or their water-soluble salts (II) used according to the invention as corrosion inhibitors for metals have the advantage over comparable compounds used as corrosion inhibitors or with regard to the chemical structure that they have completely different corrosion-inhibiting substances, for example in the way described above, are technically easy to manufacture and already at low concentrations in the aqueous in question Systems have an extremely high corrosion-inhibiting effect. This effect is largely independent of the pH. In addition, they have no detrimental, in particular no toxic, effect and can therefore be used without hesitation in water that is ultimately released into the environment from the systems mentioned. In comparison to phosphorus-containing corrosion-inhibiting agents, they also do not lead to eutrophication of the water. Furthermore, when using the corrosion inhibitors according to the invention, no zinc salts which pollute the waste water with regard to their fish toxicity are required. There is also no deposition of zinc hydroxide, which usually occurs when using zinc salts in service water systems. Another important advantage is the fact that they can be used without difficulty with other known additives, such as stone protection and dispersing agents, non-ferrous metal inhibitors or biocides and, together with them, show an additionally improved corrosion-inhibiting behavior.

Kommt es also auf die ökologischen Aspekte an, d.h. auf eine völlig Freiheit der wässrigen Kühlwasser- oder Brauchwassersysteme von Zink und Phosphor, so entspricht die alleinige Verwendung der Ester der For­mel (I) und/oder deren Salze der allgemeinen Formel (II), bevorzugt der Natriumsalze, einer besonders be­vorzugten und vorteilhaften Ausführungsform der vor­liegenden Erfindung, die zudem hinsichtlich der korro­sionsinhibierenden Wirksamkeit deutlich besser ist als diejenige von herkömmlichen Komplexbildnern. Es konnte jedoch überraschend im Rahmen der vorliegenden Erfin­dung gezeigt werden, daß die Kombination von für korrosionsinhibierende Mittel verwendeten Komplexbild­nern mit den Estern (I) der vorliegenden Erfindung und/oder deren Salzen (II) zu einer deutlichen Ver­besserung des Korrosionsschutzes führt. Dies ist be­sonders dann von Vorteil, wenn beispielsweise in ge­schlossenen Kühlsystemen ein geringer Phosphorgehalt, wie er beispielsweise aus der Gegenwart von Phosphon­säuren als Komplexbildnern resultiert, in Kauf genom­men werden kann. Als eine weitere bevorzugte Ausfüh­rungsform im Sinne der vorliegenden Erfindung ist es also anzusehen, Dicarbonsäuremono-(2-hydroxydodecyl)­ester (I) und/oder deren wasserlösliche Salze (II) in Kombination mit einem oder mehreren Komplexbildnern zur Korrosionsinhibierung in wässrigen Systemen zu verwenden. Die Ester (I) und deren wasserlösliche Sal­ze (II), von denen das Natriumsalz gegenüber den an­deren Alkalimetallsalzen oder dem Ammoniumsalz beson­ders bevorzugt ist, können einzeln oder auch in be­liebigen Mischungen miteinander verwendet werden.If the ecological aspects are important, that is to say that the aqueous cooling water or process water systems are completely free of zinc and phosphorus, the sole use of the esters of the formula (I) and / or their salts corresponds to the general formula (II), preferably the sodium salts, a particularly preferred and advantageous embodiment of the present invention, which is also significantly better than that of conventional complexing agents in terms of the corrosion-inhibiting activity. However, it could surprisingly be shown in the context of the present invention that the combination of for Corrosion inhibiting agents used complexing agents with the esters (I) of the present invention and / or their salts (II) leads to a significant improvement in corrosion protection. This is particularly advantageous when, for example in closed cooling systems, a low phosphorus content, such as may result from the presence of phosphonic acids as complexing agents, can be accepted. A further preferred embodiment within the meaning of the present invention should therefore be considered to use dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) and / or its water-soluble salts (II) in combination with one or more complexing agents for inhibiting corrosion in aqueous systems. The esters (I) and their water-soluble salts (II), of which the sodium salt is particularly preferred over the other alkali metal salts or the ammonium salt, can be used individually or in any mixtures with one another.

Für derartige bevorzugte Kombinationen kommen Komplex­bildner aus der Gruppe Ethylendiamintetraessigsäure, Nitrilotriessigsäure, Citronensäure, Phosphorsäure­ester von ethoxylierten Zuckern sowie Phosphonsäure bzw. der wasserlöslichen Salze dieser Säuren, insbe­sondere der Natriumsalze, in Frage. Von den Phosphor­säureestern von ethoxylierten Zuckern eignen sich Ester solcher Zucker, die einen Ethoxylierungsgrad von 1 bis 10, bevorzugt von 1 bis 5 aufweisen. Die Zucker sind dabei aus der Gruppe Sorbit, Mannit, Glucose und Gemischen zweier oder dreier dieser Zucker in beliebi­gem Mengenverhältnis miteinander ausgewählt.Complexing agents from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, citric acid, phosphoric acid esters of ethoxylated sugars and phosphonic acid or the water-soluble salts of these acids, in particular the sodium salts, are suitable for such preferred combinations. Of the phosphoric acid esters of ethoxylated sugars, esters of such sugars are suitable which have a degree of ethoxylation of 1 to 10, preferably 1 to 5. The sugars are selected from the group of sorbitol, mannitol, glucose and mixtures of two or three of these sugars in any proportion with one another.

Als Phosphonsäuren können alle für die Zwecke der Kom­plexbildung geeigneten Phosphonsäuren verwendet wer­ den, wobei Phosphonsäuren aus der Gruppe 1-Hydroxy­ethan-1.1-diphosphonsäure, Aminotris-(methylenphos­phonsäure) und 2-Phosphonobutan-1.2.4-tricarbonsäure sowie die wasserlöslichen Salze derartiger Phosphon­säuren geeignet sind. Diese können ebenfalls einzeln oder in beliebigen Mischungen miteinander verwendet werden.All phosphonic acids suitable for the purpose of complex formation can be used as phosphonic acids the, where phosphonic acids from the group 1-hydroxyethane-1,1-diphosphonic acid, aminotris- (methylenephosphonic acid) and 2-phosphonobutane-1.2.4-tricarboxylic acid and the water-soluble salts of such phosphonic acids are suitable. These can also be used individually or in any mixtures with one another.

Die Konzentration der Kombination aus Dicarbonsäure­mono-(2-hydroxydodecyl)ester (I) bzw. deren wasser­löslichen Salzen (II) einerseits und einem oder mehre­ren Komplexbildnern aus der oben genannten Gruppe an­dererseits in der wässrigen Lösung liegt dabei im Be­reich von 1 bis 100 ppm, bevorzugt im Bereich von 2 bis 60 ppm. Das Verhältnis der Komponenten Ester (I) und/oder deren Salze (II) zu Komplexbildner liegt er­findungsgemäß im Bereich zwischen 5 : 1 und 1 : 5, wobei ein Bereich von 2 : 1 bis 1 : 2 besonders bevor­zugt ist.The concentration of the combination of mono- (2-hydroxydodecyl) dicarboxylic acid (I) or its water-soluble salts (II) on the one hand and one or more complexing agents from the above-mentioned group on the other hand in the aqueous solution is in the range from 1 to 100 ppm, preferably in the range from 2 to 60 ppm. According to the invention, the ratio of the components ester (I) and / or their salts (II) to complexing agents is in the range between 5: 1 and 1: 5, a range from 2: 1 to 1: 2 being particularly preferred.

Wenn auch (im Falle der Phosphorsäureester der ethoxy­lierten Zucker bzw. der Phosphonsäuren) ein geringer Phosphorgehalt in den korrosionsinhibierenden Kombi­nationen in Kauf genommen werden muß, so zeigt sich doch deutlich, daß die Kombination aus einer oder meh­reren Verbindungen (I) und/oder (II) mit einem der genannten Komplexbildner eine weitere signifikante Verbesserung der Korrosionsschutzwerte erbringt. Die korrosionsinhibierende Wirkung ist auch bei Verwendung derartiger Kombinationen in weiten Grenzen vom pH-Wert unabhangig, da sich im sauren ph-Wert-Bereich, bei­spielsweise bei einem pH-Wert von 6,5, unmittelbar die Säureform der Ester, also die Verbindung (I), bildet, während be alkalischen pH-Werten, beispielsweise bei einem pH-Wert von 8,2, die Alkalimetall- oder Ammo­niumsalze der Ester, also die Verbindungen (II), vor­liegen. Vorteilhafterweise können auch die erfindungs­gemäßen Kombinationen aus Verbindungen (I) und/oder (II) mit einem oder mehreren der genannten Komplex­bildner ohne Schwierigkeiten mit weiteren, in derar­tigen Systemen üblichen Zusätzen versetzt werden, mit der Folge, daß sich zusammen mit diesen ein zusätzlich verbesserter Korrosionsschutz ausbildet. Als derartige Zusätze sind beispielsweise Steinschutz- und/oder Dis­pergiermittel, Buntmetallinhibitoren oder Biozide aus den oben angegebenen Gruppen zu nennen.Even if (in the case of the phosphoric acid esters of the ethoxylated sugars or the phosphonic acids) a low phosphorus content in the corrosion-inhibiting combinations has to be accepted, it clearly shows that the combination of one or more compounds (I) and / or (II ) brings about a further significant improvement in the corrosion protection values with one of the complexing agents mentioned. The corrosion-inhibiting effect, even when using such combinations, is largely independent of the pH, since the acid form of the esters, that is to say the compound (I.), Immediately changes in the acidic pH range, for example at a pH of 6.5 ), forms during alkaline pH values, for example at a pH of 8.2, the alkali metal or ammonium salts of the esters, that is to say the compounds (II), are present. Advantageously, the combinations according to the invention of compounds (I) and / or (II) with one or more of the complexing agents mentioned can also be mixed with other additives customary in such systems without difficulty, with the result that, together with these, an additionally improved corrosion protection trains. Examples of such additives are stone protection agents and / or dispersants, non-ferrous metal inhibitors or biocides from the groups specified above.

Die Erfindung wird durch die nachfolgenden Beispiele näher erläutert.The invention is illustrated by the following examples.

Beispiel 1example 1

Bestimmung des korrosionsinhibierenden Verhaltens der Verbindungen (I) und (II)Determination of the corrosion-inhibiting behavior of the compounds (I) and (II)

Je drei sorgfältig vorbehandelte - d.h. entfettete, gebeizte und getrocknete - Testbleche (Material: Band­stahl St 1203 (DIN 1623); Größe: 75 mm x 10 mm x 1 mm) wurden bei Raumtemperatur 6 h in ein 1-1-Becherglas eingetaucht, das mit 800 ml Versuchswasser gefüllt war, in dem eine bestimmte Menge des erfindungsgemäß verwendeten Dicarbonsäuremono-(2-hydroxydodecyl)esters (I) oder dessen Natriumsalz gelöst war (vgl. Tabelle 1). Die wässrige Lösung wurde während des Versuches mit 100 Upm gerührt.Three carefully pretreated - i.e. degreased, pickled and dried - test sheets (material: steel strip St 1203 (DIN 1623); size: 75 mm x 10 mm x 1 mm) were immersed at room temperature for 6 hours in a 1 liter beaker filled with 800 ml test water , in which a certain amount of the dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) or its sodium salt used according to the invention was dissolved (cf. Table 1). The aqueous solution was stirred at 100 rpm during the experiment.

Nach Abschluß des Versuches wurden die Bleche von Kor­rosionsprodukten gereinigt und der Gewichtsverlust gravimetrisch bestimmt. Aus dem Mittelwert von drei Versuchen wurde der Korrosionsschutzwert des erfin­dungsgemäßen Inhibitors, bezogen auf einen Blindwert, gemäß nachfolgender Formel ermittelt:
S (%) = 100 . (1 -

Figure imgb0008
)
S = Korrosionsschutzwert
a = Gewichtsverlust des Bleches, mit Inhibitor behandelt
b = Gewichtsverlust des Bleches, ohne Inhibitor behandelt.After the end of the experiment, the sheets were cleaned of corrosion products and the weight loss determined gravimetrically. The corrosion protection value of the inhibitor according to the invention, based on a blank value, was determined from the mean of three tests according to the following formula:
S (%) = 100. (1 -
Figure imgb0008
)
S = corrosion protection value
a = weight loss of the sheet, treated with inhibitor
b = weight loss of the sheet, treated without inhibitor.

Der Blindwert wurde an Blechen gleicher Qualität nach Behandlung mit einer wässrigen Lösung ohne erfindungs­gemäßen Inhibitor bestimmt.The blank value was determined on sheets of the same quality after treatment with an aqueous solution without the inhibitor according to the invention.

Das als korrosives Medium benutzte Versuchswasser hat­te folgende analytischen Daten:
8°dH (Calciumhärte);
2°dH (Magnesiumhärte);
1°dH (Carbonathärte) und
500 ppm Cl⊖.The test water used as the corrosive medium had the following analytical data:
8 ° dH (calcium hardness);
2 ° dH (magnesium hardness);
1 ° dH (carbonate hardness) and
500 ppm Cl ⊖ .

Die nachstehende Tabelle 1 gibt die Ergebnisse der Korrosionsschutzversuche bei Verwendung von Dicarbon­säuremono-(2-hydroxydodecyl)estern (DHDE) bzw. deren Natriumsalzen wieder.

Figure imgb0009
Table 1 below shows the results of the corrosion protection tests when using dicarboxylic acid mono- (2-hydroxydodecyl) esters (DHDE) or their sodium salts.
Figure imgb0009

Vergleichsbeispiel 1Comparative Example 1

Analog Beispiel 1 wurden - im Vergleich zu DHDE und den Na-Salzen der DHDE - weitere an sich bekannte Korrosionsinhibitoren sowie den DHDE strukturell ähn­liche Substanzen getestet. Die Ergebnisse sind der nachfolgenden Tabelle 2 zu entnehmen.

Figure imgb0010
Analogously to Example 1, in comparison to DHDE and the Na salts of DHDE, other corrosion inhibitors known per se and structurally similar substances were tested. The results are shown in Table 2 below.
Figure imgb0010

Ergebnis:Result:

Wie ein Vergleich der Werte in den Tabellen 1 und 2 zeigt, läßt sich mit Dicarbonsäuremono-(2-hydroxydode­cyl)estern (I), bzw. deren Na-Salzen als Korrosions­inhibitor sowohl in schwach saurem als auch schwach basischem Milieu ein deutlich besserer Korrosions­schutz als mit den den DHDE strukturell ähnlichen Ver­bindungen - siehe Versuch a bis g - beobachten. Bei den Vergleichsverbindungen a bis f handelt es sich um entsprechende Dicarbonsäuremonoester mit kürzeren bzw. längeren Kohlenstoff-Ketten in den Ester-Alkylgruppen; im Falle der Vergleichsverbindung g weist die Ester-­Alkylgruppe - bei einer Kettenlänge von 12 C-Atomen - keine Hydroxylgruppe auf. Im Vergleich zu den aus dem Stand der Technik bekannten Korrosionsinhibitoren - siehe Versuch h bis k - resultieren bessere bzw. ver­gleichbare Werte, wobei jedoch bei Verwendung der DHDE kein Phosphor und kein Zink in das Abwasser gelangen und auch keinerlei Ausfällungen entstehen.As a comparison of the values in Tables 1 and 2 shows, dicarboxylic acid mono- (2-hydroxydodecyl) esters (I), or their Na salts as corrosion inhibitors, can provide significantly better corrosion protection in both weakly acidic and weakly basic environments than with the structurally similar compounds to DHDE - see experiments a to g. The comparison compounds a to f are corresponding dicarboxylic acid monoesters with shorter or longer carbon chains in the ester alkyl groups; in the case of the comparative compound g, the ester alkyl group - with a chain length of 12 carbon atoms - has no hydroxyl group. In comparison to the corrosion inhibitors known from the prior art - see experiment h to k - better or comparable values are obtained, but when using the DHDE no phosphorus and no zinc get into the waste water and no precipitation occurs.

Beispiel 2Example 2

Bestimmung des korrosionsinhibierenden Verhaltens einer Kombination aus Ester (I) oder dessen Natrium­salz (II) mit einem KomplexbildnerDetermination of the corrosion-inhibiting behavior of a combination of ester (I) or its sodium salt (II) with a complexing agent

Analog zu dem in Beispiel 1 beschriebenen Vorgehen wurde eine entsprechende Anzahl von Testblechen in einer wässrigen Lösung behandelt, die eine Kombination aus DHDE (I) oder dessen Natriumsalz (II) und einem Komplexbildner enthielt, die in Tabelle 3 genannt ist. Die Bleche wurden wie in Beispiel 1 beschrieben behan­delt und der Korrosionsschutzwert der erfindungsgemäß verwendeten Kombination, bezogen auf einen Blindwert, gemäß der in Beispiel 1 genannten Formel ermittelt.Analogously to the procedure described in Example 1, a corresponding number of test sheets were treated in an aqueous solution which contained a combination of DHDE (I) or its sodium salt (II) and a complexing agent, which is mentioned in Table 3. The sheets were treated as described in Example 1 and the corrosion protection value of the combination used according to the invention, based on a blank value, was determined in accordance with the formula given in Example 1.

Die Ergebnisse sind der nachfolgenden Tabelle 3 zu entnehmen.The results are shown in Table 3 below.

Vergleichsbeispiel 2Comparative Example 2

Analog Beispiel 2 wurden im Vergleich zur Kombination aus DHDE bzw. deren Natriumsalzen und Komplexbildner weitere an sich bekannte Korrosionsinhibitoren, zum Teil zusammen mit Zinksalzen, hinsichtlich ihres korrosionsinhibierenden Verhaltens getestet. Die Er­gebnisse sind der nachfolgenden Tabelle 4 zu entneh­men.

Figure imgb0011
Figure imgb0012
 Analogously to Example 2, in comparison to the combination of DHDE or its sodium salts and complexing agents, further corrosion inhibitors known per se, in some cases together with zinc salts, were tested with regard to their corrosion-inhibiting behavior. The results are shown in Table 4 below.
Figure imgb0011
Figure imgb0012

Ergebnis:Result:

Wie ein Vergleich der Werte in Tabelle 3 und 4 zeigt, liegen bei gleichen Einsatzkonzentrationen die Korro­sionsschutzwerte für die Kombination aus DHDE (I) (bei pH 6,5) bzw. deren Natriumsalzen (bei pH 8,2) und Kom­plexbildnern deutlich über den Werten für die Komplex­bildner alleine und sind vergleichbar mit den Werten, die mit Komplexbildnern in Kombination mit einem Zink­salz erhalten werden. Letztere Kombination besitzt jedoch den in allen Fällen auftretenden Nachteil, daß Zinksalze in der Lösung zugegen sind und zusätzlich Abscheidungen von Zinkhydroxid auftreten, die zu einer Verschlammung der zu schützenden Anlagen führen.As a comparison of the values in Tables 3 and 4 shows, the corrosion protection values for the combination of DHDE (I) (at pH 6.5) or their sodium salts (at pH 8.2) and complexing agents are significantly higher at the same use concentrations for the complexing agents alone and are comparable to the values obtained with complexing agents in combination with a zinc salt. However, the latter combination has the disadvantage, which occurs in all cases, that zinc salts are present in the solution and additionally deposits of zinc hydroxide occur, which lead to silting up of the systems to be protected.

Beispiel 3Example 3 Allgemeine Darstellung der DicarbonsäuremonoesterGeneral representation of the dicarboxylic acid monoesters

1 mol 1,2-Dodecandiol wird mit 1 mol des entsprechen­den Anhydrids in 500 ml Toluol 6 h am Rückfluß ge­kocht, dann abgekühlt und das ausgefallene Produkt abgesaugt.

  • a) Bernsteinsäuremono-(2-hydroxydodecyl)-ester Säurezahl: 177, Schmelzpunkt: 91°C
  • b) Glutarsäuremono-(2-hydroxydodecyl)-ester Säurezahl: 182, Schmelzpunkt: 78°C
  • c) Itaconsäuremono-(2-hydroxydodecyl)-ester Säurezahl: 178, Schmelzpunkt: 104°C
  • d) Phthalsäuremono-(2-hydroxydodecyl)-ester Säurezahl: 148, Schmelzpunkt: 97°C
1 mol of 1,2-dodecanediol is refluxed with 1 mol of the corresponding anhydride in 500 ml of toluene for 6 hours, then cooled and the product which has precipitated is filtered off with suction.
  • a) succinic acid mono- (2-hydroxydodecyl) ester acid number: 177, melting point: 91 ° C.
  • b) Glutaric acid mono- (2-hydroxydodecyl) ester acid number: 182, melting point: 78 ° C.
  • c) Itaconic acid mono- (2-hydroxydodecyl) ester acid number: 178, melting point: 104 ° C.
  • d) Phthalic acid mono- (2-hydroxydodecyl) ester acid number: 148, melting point: 97 ° C.

Claims (17)

1. Dicarbonsäuremono-(2-hydroxydodecyl)ester der allgemeinen Formel (I)
Figure imgb0013
 und deren Salze der allgemeinen Formel (II)
Figure imgb0014
 in welchen A für die Reste -(CH₂)₂-, -(CH₂)₃-,
Figure imgb0015
 und M für ein Alkalimetall oder die Ammoniumgruppe steht.1. Dicarboxylic acid mono- (2-hydroxydodecyl) ester of the general formula (I)
Figure imgb0013
 and their salts of the general formula (II)
Figure imgb0014
 in which A for the residues - (CH₂) ₂-, - (CH₂) ₃-,
Figure imgb0015
 and M represents an alkali metal or the ammonium group. 2. Verbindungen (II) nach Anspruch 1, dadurch gekenn­zeichnet, daß M für Natrium, Kalium oder die Ammonium­gruppe und insbesondere für Natrium steht.2. Compounds (II) according to claim 1, characterized in that M represents sodium, potassium or the ammonium group and in particular sodium. 3. Verwendung von Dicarbonsäuremono-(2-hydroxydode­cyl)estern der allgemeinen Formel (I)
Figure imgb0016
 und/oder deren Salze der allgemeinen Formel (II)
Figure imgb0017
 in welchen A für die Reste -(CH₂)₂-, -(CH₂)₃-,
Figure imgb0018
 und M für ein Alkalimetall oder die Ammoniumgruppe steht, in Konzentrationen von 1 bis 100 ppm als Korro­sionsinhibitoren in wässrigen Systemen, gegebenenfalls in Gegenwart weiterer, an sich bekannter Steinschutz- und/oder Dispergiermittel und/oder Buntmetallinhibito­ren und/oder Mikrobizide.3. Use of dicarboxylic acid mono- (2-hydroxydodecyl) esters of the general formula (I)
Figure imgb0016
 and / or their salts of the general formula (II)
Figure imgb0017
 in which A for the residues - (CH₂) ₂-, - (CH₂) ₃-,
Figure imgb0018
 and M represents an alkali metal or the ammonium group, in concentrations of 1 to 100 ppm as corrosion inhibitors in aqueous systems, if appropriate in the presence of further stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides known per se. 4. Verwendung nach Anspruch 3, dadurch gekennzeichnet, daß Dicarbonsäuremono-(2-hydroxydodecyl)ester (I) als Korrosionsinhibitor in Konzentrationen von 1 bis 100 ppm in Wasser gelöst ist.4. Use according to claim 3, characterized in that dicarboxylic acid mono- (2-hydroxydodecyl) ester (I) is dissolved as a corrosion inhibitor in concentrations of 1 to 100 ppm in water. 5. Verwendung nach Anspruch 3, dadurch gekennzeichnet, daß ein oder mehrere wasserlösliche Salze (II) von Dicarbonsäuremono-(2-hydroxydodecyl)estern als Korro­sionsinhibitoren in Konzentrationen von 1 bis 100 ppm in Wasser gelöst sind.5. Use according to claim 3, characterized in that one or more water-soluble salts (II) of dicarboxylic acid mono- (2-hydroxydodecyl) esters as corrosion inhibitors are dissolved in water in concentrations of 1 to 100 ppm. 6. Verwendung nach Anspruch 5, dadurch gekennzeichnet, daß als wasserlösliche Salze Natrium-, Kalium- oder Ammoniumsalze in Wasser gelöst sind.6. Use according to claim 5, characterized in that sodium, potassium or ammonium salts are dissolved in water as the water-soluble salts. 7. Verwendung nach Ansprüchen 3 bis 6, dadurch gekenn­zeichnet, daß die Konzentration von Dicarbonsäuremono-­(2-hydroxydodecyl)estern und/oder deren wasserlös­lichen Salzen im Bereich von 10 bis 50 ppm liegt.7. Use according to claims 3 to 6, characterized in that the concentration of dicarboxylic acid mono- (2-hydroxydodecyl) esters and / or their water-soluble salts is in the range of 10 to 50 ppm. 8. Verwendung von
(a) Dicarbonsäuremono-(2-hydroxydodecyl)estern (I) und/oder deren wasserlöslichen Salzen (II) in Kom­bination mit
(b) einem oder mehreren Komplexbildnern aus der Gruppe Ethylendiamintetraessigsäure, Nitrilotriessig­säure, Citronensäure, Phosphorsäureester von eth­oxylierten Zuckern sowie Phosphonsäure bzw. der wasserlöslichen Salze dieser Säuren, insbesondere der Natriumsalze,
(c) gegebenenfalls in Gegenwart weiterer, an sich be­kannter Steinschutz- und/oder Dispergiermittel und/oder Buntmetallinhibitoren und/oder Mikrobi­zide
als Korrosionsinhibitoren in wässrigen Systemen, wobei die Konzentration des Gemisches aus den Komponenten (a) und (b) in wässriger Lösung im Bereich von 1 bis 100 ppm und das Verhältnis der Komponenten (a) zu (b) im Bereich zwischen 5 : 1 und 1 : 5 liegt.8. Use of
(a) Dicarboxylic acid mono- (2-hydroxydodecyl) esters (I) and / or their water-soluble salts (II) in combination with
(b) one or more complexing agents from the group consisting of ethylenediaminetetraacetic acid, nitrilotriacetic acid, citric acid, phosphoric acid esters of ethoxylated sugars and phosphonic acid or the water-soluble salts of these acids, in particular the sodium salts,
(c) if appropriate in the presence of further stone protection and / or dispersants and / or non-ferrous metal inhibitors and / or microbicides known per se
as corrosion inhibitors in aqueous systems, the concentration of the mixture of components (a) and (b) in aqueous solution in the range from 1 to 100 ppm and the ratio of components (a) to (b) in the range between 5: 1 and 1: 5 lies. 9. Verwendung nach Anspruch 8, dadurch gekennzeichnet, daß die Konzentration des Gemisches der Komponenten (a) und (b) im Wasser im Bereich von 2 bis 60 ppm liegt.9. Use according to claim 8, characterized in that the concentration of the mixture of components (a) and (b) in the water is in the range of 2 to 60 ppm. 10. Verwendung nach Ansprüchen 8 und 9, dadurch ge­kennzeichnet, daß das Verhältnis der Komponenten (a) zu den Komponenten (b) im Bereich von 2 : 1 bis 1 : 2 liegt.10. Use according to claims 8 and 9, characterized in that the ratio of components (a) to components (b) is in the range from 2: 1 to 1: 2. 11. Verwendung nach Ansprüchen 8 bis 10, dadurch ge­kennzeichnet, daß als Komplexbildner eine oder mehrere Phosphonsäuren aus der Gruppe 1-Hydroxyethan-1.1-di­phosphonsäure, Aminotris-(methylenphosphonsäure) und 2-Phosphono-butan-1.2.4-tricarbonsäure und deren was­serlösliche Salze eingesetzt werden.11. Use according to claims 8 to 10, characterized in that the complexing agent is one or more phosphonic acids from the group 1-hydroxyethane-1,1-diphosphonic acid, aminotris (methylenephosphonic acid) and 2-phosphonobutane-1.2.4-tricarboxylic acid and their water-soluble Salts are used. 12. Verwendung nach Ansprüchen 8 bis 10, dadurch ge­kennzeichnet, daß als Komplexbildner Phosphorsäure­ester von ethoxylierten Zuckern mit einem Ethoxylie­rungsgrad von 1 bis 10, bevorzugt von 1 bis 5, einge­setzt werden, wobei die Zucker aus der Gruppe Sorbit, Mannit und Glucose und deren Gemischen ausgewählt sind.12. Use according to claims 8 to 10, characterized in that phosphorus esters of ethoxylated sugars with a degree of ethoxylation of 1 to 10, preferably 1 to 5, are used as complexing agents, the sugars from the group sorbitol, mannitol and glucose and mixtures thereof are selected. Verwendung nach Ansprüchen 3 bis 12, dadurch ge­kennzeichnet, daß gegebenenfalls als weitere Zusätze Steinschutz- und/oder Dispergiermittel in Mengen von 1 bis 50 ppm und/oder Buntmetallinhibitoren in Mengen von 0,1 bis 5 ppm und/oder Mikrobizide in Mengen von 1 bis 100 ppm in Wasser gelöst sind.Use according to Claims 3 to 12, characterized in that stone protection and / or dispersing agents in amounts of 1 to 50 ppm and / or non-ferrous metal inhibitors in amounts of 0.1 to 5 ppm and / or microbicides in amounts of 1 to 100 ppm are dissolved in water. 14. Verwendung nach Ansprüchen 3 bis 13, dadurch ge­kennzeichnet, daß gegebenenfalls als Steinschutz- und/­ oder Dispergiermittel Polyacrylate und/oder Copolyme­risate von Acrylsäure und/oder Methacrylsäure und/oder deren Derivaten mit einer mittleren Molekularmasse im Bereich von 500 bis 4000 und/oder Ethylenoxid-Propy­lenoxid-Blockcopolymere mit einer mittleren Molekular­masse im Bereich von 500 bis 3000 und einem Ethylen­oxid-Propylenoxid Verhältnis von 10 : 90 bis 30 : 70, bevorzugt in Mengen von 3 bis 10 ppm, in Wasser gelöst sind.14. Use according to claims 3 to 13, characterized in that optionally as a stone protection and / or dispersants polyacrylates and / or copolymers of acrylic acid and / or methacrylic acid and / or their derivatives with an average molecular weight in the range from 500 to 4000 and / or ethylene oxide-propylene oxide block copolymers with an average molecular weight in the range from 500 to 3000 and an ethylene oxide Propylene oxide ratio of 10:90 to 30:70, preferably in amounts of 3 to 10 ppm, are dissolved in water. 15. Verwendung nach Ansprüchen 3 bis 13, dadurch ge­kennzeichnet, daß als Buntmetallinhibitoren 3-Heptyl-­5-amino-1.2.4-triazol, Benzimidazol, Benzotriazol und/­oder Tolyltriazol in Wasser gelöst sind.15. Use according to claims 3 to 13, characterized in that 3-heptyl-5-amino-1,2,4-triazole, benzimidazole, benzotriazole and / or tolyltriazole are dissolved in water as non-ferrous metal inhibitors. 16. Verwendung nach Ansprüchen 3 bis 13, dadurch ge­kennzeichnet, daß gegebenenfalls als Mikrobizide Glu­taraldehyd, Glyoxal und/oder Alkyloligoamide, bevor­zugt ein Umsetzungsprodukt von Dodecylpropylendiamin und ε-Caprolactam im Molverhältnis 1 : 2, in Wasser gelöst sind.16. Use according to claims 3 to 13, characterized in that optionally as microbicides glutaraldehyde, glyoxal and / or alkyloligoamides, preferably a reaction product of dodecylpropylenediamine and ε-caprolactam in a molar ratio of 1: 2, are dissolved in water. 17. Verwendung nach Ansprüchen 3 bis 16, dadurch ge­kennzeichnet, daß die wässrigen Systeme Brauchwasser­systeme sind.17. Use according to claims 3 to 16, characterized in that the aqueous systems are process water systems.
EP87108076A 1986-06-12 1987-06-04 2-hydroxydodecylmonoesters of dicarboxylic acids, their salts and their use as corrosion inhibitors in aqueous systems Withdrawn EP0249148A3 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0405873A1 (en) * 1989-06-27 1991-01-02 Nabisco, Inc. Long chain diol diesters as low calorie fat mimetics
EP2312019A1 (en) * 2009-10-01 2011-04-20 Rhein Chemie Rheinau GmbH Anti-corrosion additive for finishing processes, method for its production and use for metals corrosion protection

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5089150A (en) * 1990-05-29 1992-02-18 Mobil Oil Corporation Method of increasing retention of scale inhibitors in subterranean formations
TWI252249B (en) * 1999-11-12 2006-04-01 Yasuo Fukutani Rust preventive

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2364883A1 (en) * 1976-09-20 1978-04-14 Henkel Kgaa NEW 2-HYDROXYALKYL ESTERS OF POLYCARBOXYLIC ACIDS, THEIR USE AS EMULSIFIERS, AS WELL AS THE COSMETIC EMULSIONS CONTAINING THESE PRODUCTS
GB2011403A (en) * 1977-12-22 1979-07-11 Henkel Kgaa Mono-and dicarboxylic acid-2-hydroxyalkyl esters their useas emulsifiers and cosmentic emulsions containing them

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3127432A1 (en) * 1981-07-11 1983-02-03 Bayer Ag, 5090 Leverkusen METHOD FOR PRODUCING FUMAR ACID MONOESTER
DE3300874A1 (en) * 1983-01-13 1984-07-19 Henkel KGaA, 4000 Düsseldorf Succinic acid derivatives as corrosion protection agents

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2364883A1 (en) * 1976-09-20 1978-04-14 Henkel Kgaa NEW 2-HYDROXYALKYL ESTERS OF POLYCARBOXYLIC ACIDS, THEIR USE AS EMULSIFIERS, AS WELL AS THE COSMETIC EMULSIONS CONTAINING THESE PRODUCTS
GB2011403A (en) * 1977-12-22 1979-07-11 Henkel Kgaa Mono-and dicarboxylic acid-2-hydroxyalkyl esters their useas emulsifiers and cosmentic emulsions containing them

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0405873A1 (en) * 1989-06-27 1991-01-02 Nabisco, Inc. Long chain diol diesters as low calorie fat mimetics
EP2312019A1 (en) * 2009-10-01 2011-04-20 Rhein Chemie Rheinau GmbH Anti-corrosion additive for finishing processes, method for its production and use for metals corrosion protection

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Withdrawal date: 19910118

R18W Application withdrawn (corrected)

Effective date: 19910118

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WEHLE, VOLKER, DR.

Inventor name: PENNINGER, JOSEF, DR.