EP0192132A2 - Aqueous anticorrosive agent containing an ammonium salt of 2-benzothia-zolylthiocarboxylic acid - Google Patents

Aqueous anticorrosive agent containing an ammonium salt of 2-benzothia-zolylthiocarboxylic acid Download PDF

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Publication number
EP0192132A2
EP0192132A2 EP86101564A EP86101564A EP0192132A2 EP 0192132 A2 EP0192132 A2 EP 0192132A2 EP 86101564 A EP86101564 A EP 86101564A EP 86101564 A EP86101564 A EP 86101564A EP 0192132 A2 EP0192132 A2 EP 0192132A2
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Prior art keywords
acid
aqueous
zolylthiocarboxylic
benzothia
agent containing
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EP86101564A
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German (de)
French (fr)
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EP0192132A3 (en
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Francesco Dr. Cargnino
Giuseppe Dr. Natoli
Horst Lorke
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Hoechst AG
Hoechst Italia SpA
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Hoechst AG
Hoechst Italia SpA
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    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23FNON-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
    • C23F11/00Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10Inhibiting 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
    • C23F11/16Sulfur-containing compounds
    • C23F11/165Heterocyclic compounds containing sulfur as hetero atom
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M135/00Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing sulfur, selenium or tellurium
    • C10M135/32Heterocyclic sulfur, selenium or tellurium compounds
    • C10M135/36Heterocyclic sulfur, selenium or tellurium compounds the ring containing sulfur and carbon with nitrogen or oxygen
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M173/00Lubricating compositions containing more than 10% water
    • C10M173/02Lubricating compositions containing more than 10% water not containing mineral or fatty oils
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2201/00Inorganic compounds or elements as ingredients in lubricant compositions
    • C10M2201/02Water
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2215/00Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
    • C10M2215/02Amines, e.g. polyalkylene polyamines; Quaternary amines
    • C10M2215/04Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to acyclic or cycloaliphatic carbon atoms
    • C10M2215/042Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to acyclic or cycloaliphatic carbon atoms containing hydroxy groups; Alkoxylated derivatives thereof
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2219/00Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
    • C10M2219/10Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2219/00Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
    • C10M2219/10Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
    • C10M2219/102Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon only in the ring
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2219/00Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
    • C10M2219/10Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
    • C10M2219/104Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon with nitrogen or oxygen in the ring
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10MLUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2219/00Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
    • C10M2219/10Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
    • C10M2219/104Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon with nitrogen or oxygen in the ring
    • C10M2219/106Thiadiazoles
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10NINDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/12Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10NINDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00Specified use or application for which the lubricating composition is intended
    • C10N2040/20Metal working
    • C10N2040/22Metal working with essential removal of material, e.g. cutting, grinding or drilling
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10NINDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2050/00Form in which the lubricant is applied to the material being lubricated
    • C10N2050/01Emulsions, colloids, or micelles

Definitions

  • cooling lubricants in the form of aqueous mineral oil emulsions are often used.
  • Purely aqueous cooling lubricants that do not contain oils are increasingly being used for this purpose.
  • These are essentially combinations of salts of organic acids with water-soluble polyadducts, which are obtained by adding ethylene oxide, propylene oxide and / or butylene oxide to compounds having active hydrogen atoms.
  • aqueous mineral oil emulsions When using the aqueous mineral oil emulsions as cooling liquids, it is disadvantageous that these emulsions break easily, which is particularly due to thermal influences, to a change in pH or to a change in the electrolyte charge. Consequently, changing these parameters will adversely affect the quality of the emulsions, so that after a certain time the emulsion is no longer usable.
  • Another disadvantage of mineral oil emulsions is that their milky appearance makes it difficult to observe the machining process.
  • DE-AS 11 49 843 describes additives for fuels and lubricating oils that contain salts of primary, aliphatic amines of some amido acids as rust preventives. From DE-AS 29 22 562 amine salts of dicarboxylic acids are known as rust inhibitors in aqueous systems, the lubricants containing 0.3% to 50% of these rust inhibitors. The use of 2-mercaptobenztriazole as a corrosion protection agent for copper is also known. In addition, the use of benzothiazolylmercapto-dicarboxylic acids as corrosion inhibitors is already known (EP 0 129 506).
  • the object of the present invention is to find new compounds which have an anti-corrosion effect, which have no harmful effects on the operating personnel or on the environment and which can be used not only with ferrous metals but also with copper and aluminum.
  • the invention thus relates to aqueous anticorrosive agents which contain an ammonium salt of 2-benzothiazolylthiocarboxylic acid of the formula contain, where n is a number from 1 to 6 and M is an organic ammonium ion.
  • 2-benzothiazolylthiocarboxylic acids are prepared by reacting 2-mercaptobenzothiazole with M -halocarboxylic acids.
  • M -halocarboxylic acids instead of the free mercaptobenzthiazole and the free halocarboxylic acid, it is also possible to use their alkali metal salts.
  • the molar ratio of the two starting compounds is approximately 1: 1.
  • the reaction is generally carried out at a temperature of 30 to 80 ° C. and for a period of 1 to 4 hours. After the reaction has ended, the mixture is acidified and the free acid obtained is separated off, purified and dried. To prepare the ammonium salts mentioned above, this free acid is then dissolved in an aqueous solution of the desired amine in accordance with the meaning of the symbol M. This solution can then be used directly, but is preferably further diluted with water.
  • Suitable organic ammonium ions under the meaning of M are all ammonium ions which are derived from organic amines, in particular those organic ammonium ions which, together with the anion of benzothiazolylthiocarboxylic acid, form salts which are soluble or emulsifiable in water. Particularly noteworthy are the ammonium ions, which are derived from mono-, di- and tri-methylamine, mono-, di- and tri ethylamine, monoisopropylamine, mono- and di-butylamine, 3-methoxypropylamine, trimethylpentamine, mono-, di- and tri-ethanolamine, mono-, di- and tri-isopropanolamine. For economic reasons and because of the better action, salts with the mono-, di- and tri-ethanolamine are preferred.
  • aqueous solutions of the salts of 2-benzothiazolylthiocarboxylic acids obtained are clear and also do not change when left to stand for 24 hours. No foam forms and the solutions have excellent corrosion protection for ferrous metals, copper and aluminum.
  • solutions of higher concentration with an active substance content of approximately 20 to 50% are first prepared. These commercial forms are then further diluted when used and the finished working solution contains about 0.3 to 5% by weight of active substance.
  • aqueous solutions of the ammonium salts of 2-benzothiazolylthiocarboxylic acids are generally suitable as anti-corrosion agents for ferrous metals, copper and aluminum, in particular for cooling circuits, hydraulic liquids and preferably for aqueous cooling lubricants in metal processing.
  • all of these functional fluids also contain the usual active substances necessary for the respective purpose.
  • the respective composition of these functional fluids is sufficiently known to the person skilled in the art and does not require any further explanation here.
  • the reaction is continued for a further 2 hours in the temperature range between 40 and 50 ° C.
  • the water / methanol ratio is 1: 1.
  • the solution is then acidified with hydrochloric acid or acetic acid until a pH between 1 and 3 is reached.
  • reaction is continued for two hours at a temperature of 60-70 ° C, then acidified with hydrochloric acid until no more precipitations occur.
  • 2-Benzthiazolylthiopropionic acid is obtained as a white powder which, after cleaning and drying, has a melting point of 145-147 ° C.
  • the corrosion test on copper and aluminum was carried out as follows. In four test tubes with 100 cc. 1.5 g of mixtures A, B, C and D are added to water and copper foils or aluminum foils according to DIN 1791 - E-CU 57 F30 with the dimensions 2 x 12 x 75 mm are immersed in these solutions. The test tubes are closed and Leave at 20 ° C for 20 days. At the end of the experiment, the color taken up by the solution is observed:

Abstract

Verwendung von 2-Benzthiazolylthiocarbonsäure-Ammonium-Salzen der Formel <IMAGE> wobei n eine Zahl von 1 bis 6 und M ein organisches Ammonium-Ion bedeuten, als korrosionsverhinderndes Mittel in wäßrigen Funktionsflüssigkeiten, insbesondere bei wäßrigen Kühlschmiermitteln.Use of 2-benzothiazolylthiocarboxylic acid ammonium salts of the formula <IMAGE> where n is a number from 1 to 6 and M is an organic ammonium ion, as a corrosion-preventing agent in aqueous functional fluids, especially in aqueous cooling lubricants.

Description

Bei der Bearbeitung von Metallen wie beispielsweise Bohren, Drehen, Fräsen und ähnlichen Verfahren, werden oft sogenannte Kühlschmiermittel in Form wäßriger Mineralölemulsionen verwendet. In zunehmendem Ausmaß benutzt man aber zu diesem Zweck rein wäßrige Kühlschmiermittel, die keine Öle enthalten. Hierbei handelt es sich im wesentlichen um Kombinationen von Salzen organischer Säuren mit wasserlöslichen Polyaddukten, die durch Addition von Äthylenoxid, Propylenoxid und/oder Butylenoxid an Verbindungen mit aktiven Wasserstoffatomen erhalten werden.When machining metals such as drilling, turning, milling and similar processes, so-called cooling lubricants in the form of aqueous mineral oil emulsions are often used. Purely aqueous cooling lubricants that do not contain oils are increasingly being used for this purpose. These are essentially combinations of salts of organic acids with water-soluble polyadducts, which are obtained by adding ethylene oxide, propylene oxide and / or butylene oxide to compounds having active hydrogen atoms.

Bei Verwendung der wäßrigen Mineralölemulsionen als Kühlflüsssigkeiten ist es von Nachteil, daß diese Emulsionen leicht brechen, was besonders auf thermische Einflüsse, auf die Änderung des pH-Werts oder auf einen Wechsel der Elektrolytladung zurückzuführen ist. Folglich wird eine Veränderung dieser Parameter die Qualität der Emulsionen negativ beeinflussen, so daß nach einer gewissen Zeit die Emulsion nicht mehr gebrauchsfähig ist. Ein weiterer Nachteil der Mineralölemulsionen besteht darin, daß ihr milchartiges Aussehen die Beobachtung des Bearbeitungsablaufes erschwert.When using the aqueous mineral oil emulsions as cooling liquids, it is disadvantageous that these emulsions break easily, which is particularly due to thermal influences, to a change in pH or to a change in the electrolyte charge. Consequently, changing these parameters will adversely affect the quality of the emulsions, so that after a certain time the emulsion is no longer usable. Another disadvantage of mineral oil emulsions is that their milky appearance makes it difficult to observe the machining process.

Um diese Nachteile zu vermeiden, hat deshalb bei der Bearbeitung von Metallen die Verwendung von wasserlöslichen Verbindungen eine wachsende Bedeutung gewonnen. Gegenüber den Öl-Emulsionen haben diese wäßrigen Lösungen den Vorteil einer größeren Stabilität, sie werden von Bakterien weniger angegriffen, sie sind unempfindlich gegen die Art des verwendeten Wassers und besitzen gegenüber den üblichen Ölen ein besseres Schmiervermögen.To avoid these disadvantages, the use of water-soluble compounds has therefore become increasingly important in the processing of metals. Compared to oil emulsions, these aqueous solutions have the advantage of greater stability, they are less attacked by bacteria, they are insensitive to the type of water used and have a better lubricity compared to the usual oils.

Das Hauptproblem aller dieser Flüssigkeiten liegt in einer wirksamen Rostschutzwirkung, was bis jetzt im allgemeinen durch die Verwendung von Natriumnitrit erzielt wurde. Diese Verbindung hinterläßt jedoch einen kristallinen Rest auf den damit behandelten Oberflächen, kann unter Umständen Teile der verwendeten Präzisionsmaschinen beschädigen und zersetzt sich bei hohen Temperaturen, wodurch Nitrodämpfe entstehen, die für das Bedienungspersonal schädlich sind. Das Nitrit ist überdies auch für die Umwelt schädlich, da höchstens 0,6 ppm. in den Abwässern zulässig sind. Es wurden daher Zusatzstoffe gesucht, die einerseits optimale Korrosionsschutzeigenschatten aufweisen und andererseits die oben erwähnten Probleme vermeiden sollten.The main problem with all of these liquids is an effective anti-rust effect, which has hitherto generally been achieved through the use of sodium nitrite. However, this compound leaves a crystalline residue on the surfaces treated with it, can possibly damage parts of the precision machines used and decomposes at high temperatures, resulting in nitric vapors which are harmful to the operating personnel. The nitrite is also harmful to the environment, as a maximum of 0.6 ppm. are permitted in the waste water. Therefore, additives were sought which on the one hand have optimal corrosion protection shadows and on the other hand should avoid the problems mentioned above.

Die DE-AS 11 49 843 beschreibt Zusatzstoffe für Kraftstoffe und Schmieröle, die als Rostschutzmittel Salze von primären, aliphatischen Aminen einiger Amidosäuren enthalten. Aus der DE-AS 29 22 562 sind als Rostschutzmittel in wäßrigen Systemen Aminsalze aus Dicarbonsäuren bekannt, wobei die Schmiermittel 0,3 % bis 50 % dieser Rostschutzmittel enthalten. Bekannt ist auch die Verwendung von 2-Mercaptobenztriazol als Korrosionsschutzmittel für Kupfer. Außerdem ist bereits die Verwendung von Benzthiazolylmercapto-dicarbonsäuren als Korrosionsinhibitoren bekannt (EP 0 129 506).DE-AS 11 49 843 describes additives for fuels and lubricating oils that contain salts of primary, aliphatic amines of some amido acids as rust preventives. From DE-AS 29 22 562 amine salts of dicarboxylic acids are known as rust inhibitors in aqueous systems, the lubricants containing 0.3% to 50% of these rust inhibitors. The use of 2-mercaptobenztriazole as a corrosion protection agent for copper is also known. In addition, the use of benzothiazolylmercapto-dicarboxylic acids as corrosion inhibitors is already known (EP 0 129 506).

Es ist überdies bekannt, daß alle Korrosionsschutzmittel, die als Rostschutzmittel in wäßrigen Systemen zur Bearbeitung von Metallen verwendet werden, ein gutes Korrosionsschutzvermögen nur bei höheren pH-Werten besitzen, der im allgemeinen zwischen 8 - 8,5 und 9 liegt. Dabei üben sie keine Korrosionsschutzwirkung auf Kupfer aus. Es ist auch bekannt, daß viele dieser Zusatzstoffe mit Kalziumsalzen zu Flockungen und zur Bildung von Schaum neigen, wodurch ihre Verwendung weiterhin beschränkt wird.It is also known that all anti-corrosion agents that are used as rust preventives in aqueous systems for working metals have good anti-corrosion properties only at higher pH values, which is generally between 8 - 8.5 and 9. They do not have a corrosion protection effect on copper. It is also known that many of these calcium salt additives tend to flocculate and foam, further limiting their use.

Die Aufgabe der vorliegenden Erfindung liegt darin, neue Verbindungen zu finden, die eine Korrosionsschutzwirkung haben, die keine schädlichen Auswirkungen auf das Bedienungspersonal oder auf die Umwelt haben und die nicht nur bei Eisenmetallen, sondern auch bei Kupfer und Aluminium verwendet werden können.The object of the present invention is to find new compounds which have an anti-corrosion effect, which have no harmful effects on the operating personnel or on the environment and which can be used not only with ferrous metals but also with copper and aluminum.

Diese Aufgabe wird erfindungsgemäß überraschenderweise mit Hilfe von Ammoniumsalzen der 2-Benzthiazolylthiocarbonsäure gelöst, die die gesamten, gestellten Erfordernisse erfüllen und es unerwarteterweise erlauben bei pH-Werten zu arbeiten, die in der Nähe des Neutratpunkts liegen (7 - 7,5). Da diese Verbindungen mit Kalziumsalzen überhaupt nicht zu Flockungen führen und keinen Schaum bilden, sind sie mit jeder Wasserart verwendbar, ohne daß ihr Rostschutzvermögen beeinträchtigt wird.This object is surprisingly achieved according to the invention with the aid of ammonium salts of 2-benzothiazolylthiocarboxylic acid, which meet all of the requirements and unexpectedly allow working at pH values which are close to the neutral point (7-7.5). Since these compounds with calcium salts do not lead to flocculation and do not form foam, they can be used with any type of water without affecting their rust protection properties.

Gegenstand der Erfindung sind somit wäßrige Korrosionsschutzmittel, die ein Ammonium-Salz der 2-Benzthiazolylthiocarbonsäure der Formel

Figure imgb0001
enthalten, wobei n eine Zahl von 1 bis 6 und M ein organisches Ammonium-lon bedeuten.The invention thus relates to aqueous anticorrosive agents which contain an ammonium salt of 2-benzothiazolylthiocarboxylic acid of the formula
Figure imgb0001
contain, where n is a number from 1 to 6 and M is an organic ammonium ion.

Diese 2-Benzthiazolylthiocarbonsäuren werden hergestellt durch Umsetzung von 2-Mercaptobenzthiazol mit M-Halogencarbonsäuren. Anstelle des freien Mercaptobenzthiazol und der freien Halogencarbonsäure kann man auch deren Alkalisalze nehmen.These 2-benzothiazolylthiocarboxylic acids are prepared by reacting 2-mercaptobenzothiazole with M -halocarboxylic acids. Instead of the free mercaptobenzthiazole and the free halocarboxylic acid, it is also possible to use their alkali metal salts.

Das Molverhältnis der beiden Ausgangsverbindungen beträgt ca. 1 : 1. Die Reaktion wird im allgemeinen bei einer Temperatur von 30 bis 80°C und für eine Dauer von 1 bis 4 Stunden durchgeführt. Nach Beendigung der Reaktion wird angesäuert und die erhaltene freie Säure abgetrennt, gereinigt und getrocknet Zur Herstellung der oben angegebenen Ammoniumsalze wird diese freie Säure dann in einer wäßrigen Lösung des gewünschten Amins entsprechend der Bedeutung des Symbols M gelöst. Diese Lösung ist dann direkt verwendbar, wird aber vorzugsweise noch weiter mit Wasser verdünnt.The molar ratio of the two starting compounds is approximately 1: 1. The reaction is generally carried out at a temperature of 30 to 80 ° C. and for a period of 1 to 4 hours. After the reaction has ended, the mixture is acidified and the free acid obtained is separated off, purified and dried. To prepare the ammonium salts mentioned above, this free acid is then dissolved in an aqueous solution of the desired amine in accordance with the meaning of the symbol M. This solution can then be used directly, but is preferably further diluted with water.

Als organische Ammonium-lonen unter der Bedeutung von M kommen alle Ammonium-Ionen in Frage, die sich von organischen Aminen ableiten, insbesondere solche organischen Ammonium-lonen, die zusammen mit dem Anion der Benzthiazolyl-thiocarbonsäure in Wasser lösliche oder emulgierbare Salze bilden. Insbesondere zu nennen sind dabei die Ammonium-lonen, die sich ableiten von Mono-, Di- und Tri-methylamin, Mono-, Di- und Triäthylamin, Monoisopropylamin, Mono- und Di-butylamin, 3-Methoxipropylamin, Trimethylpentamin, Mono-, Di- und Tri- äthanolamin, Mono-, Di- und Tri-isopropanolamin. Aus wirtschaftlichen Gründen und wegen der besseren Wirkung werden Salze mit dem Mono-, Di- und Tri-äthanolamin bevorzugt.Suitable organic ammonium ions under the meaning of M are all ammonium ions which are derived from organic amines, in particular those organic ammonium ions which, together with the anion of benzothiazolylthiocarboxylic acid, form salts which are soluble or emulsifiable in water. Particularly noteworthy are the ammonium ions, which are derived from mono-, di- and tri-methylamine, mono-, di- and tri ethylamine, monoisopropylamine, mono- and di-butylamine, 3-methoxypropylamine, trimethylpentamine, mono-, di- and tri-ethanolamine, mono-, di- and tri-isopropanolamine. For economic reasons and because of the better action, salts with the mono-, di- and tri-ethanolamine are preferred.

Die erhaltenen wäßrigen Lösungen der Salze der 2-Benzthiazolylthiocarbonsäuren sind klar und verändern sich auch nicht beim Stehenlassen über 24 Stunden. Es bildet sich kein Schaum und die Lösungen weisen einen ausgezeichneten Korrosionsschutz bei Eisenmetallen, Kupfer und Aluminium auf. Für die Anwendung der 2-Benzthiazolylthiocarbonsäure-Salze werden zunächst, wie allgemein auf dem Gebiet der Metallbearbeitungsmittel üblich, höher konzentrierte Lösungen mit einem Gehalt an Wirksubstanz von ca. 20 bis 50 % hergestellt. Diese Handelsformen werden dann beim Anwenden weiter verdünnt und die fertige Gebrauchslösung enthält ca. 0,3 bis 5 Gew.-% an Wirksubstanz.The aqueous solutions of the salts of 2-benzothiazolylthiocarboxylic acids obtained are clear and also do not change when left to stand for 24 hours. No foam forms and the solutions have excellent corrosion protection for ferrous metals, copper and aluminum. For the use of the 2-benzthiazolylthiocarboxylic acid salts, as is generally customary in the field of metalworking agents, solutions of higher concentration with an active substance content of approximately 20 to 50% are first prepared. These commercial forms are then further diluted when used and the finished working solution contains about 0.3 to 5% by weight of active substance.

Die wäßrigen Lösungen der Ammoniumsalze der 2-Benzthiazolylthiocarbonsäuren eignen sich ganz allgemein als Korrosionsschutzmittel bei Eisenmetallen, Kupfer und Aluminium, insbesondere bei Kühlkreisläufen, hydraulischen Flüssigkeiten und vorzugsweise bei wäßrigen Kühlschmiermitteln bei der Metallverarbeitung. All diese Funktionsflüssigkeiten enthalten neben dem beschriebenen Korrosionsschutzmittel noch die üblichen für den jeweiligen Zweck nötigen Wirksubslanzen. Im einzelnen ist die jeweilige Zusammensetzung dieser Funktionsflüssigkeiten dem Fachmann hinreichend bekannt und bedarf hier keiner näheren Erläuterung.The aqueous solutions of the ammonium salts of 2-benzothiazolylthiocarboxylic acids are generally suitable as anti-corrosion agents for ferrous metals, copper and aluminum, in particular for cooling circuits, hydraulic liquids and preferably for aqueous cooling lubricants in metal processing. In addition to the described corrosion protection agent, all of these functional fluids also contain the usual active substances necessary for the respective purpose. In particular, the respective composition of these functional fluids is sufficiently known to the person skilled in the art and does not require any further explanation here.

Beispiel 1 Example 1

167 g (1 Mol) Mercaptobenzthiazol werden mit Natriumhydroxid in Wasser gelöst und mit 500 g Methanol verdünnt. Dazu gibt man langsam bei 30 - 70°C eine wäßrige Lösung von 1,2 Mol Natriummonochloracetat. 1 67 g (1 mol) of mercaptobenzothiazole are dissolved in water with sodium hydroxide and diluted with 500 g of methanol. An aqueous solution of 1.2 mol of sodium monochloroacetate is slowly added at 30 - 70 ° C.

Die Reaktion wird für weitere 2 Stunden im Temperaturbereich zwischen 40 und 50°C fortgeführt. Das Verhältnis Wasser/Methanol beträgt 1 : 1.The reaction is continued for a further 2 hours in the temperature range between 40 and 50 ° C. The water / methanol ratio is 1: 1.

Die Lösung wird dann mit Salzsäure oder Essigsäure angesäuert, bis ein pH-Wert zwischen 1 und 3 erreicht wird.The solution is then acidified with hydrochloric acid or acetic acid until a pH between 1 and 3 is reached.

Man erhält so 2-Benzthiazolylthioessigsäure als weißes Pulver, das von den anorganischen Salzen und von den nicht umgesetzten Reaktionsprodukten gereinigt und getrocknet wird: Schm. P. 155 + 158°C.This gives 2-benzthiazolylthioacetic acid as a white powder, which is purified from the inorganic salts and from the unreacted reaction products and dried: M. P. 155 + 158 ° C.

Beispiel 2Example 2

Einer wäßrigen Lösung, die ein Mol des Natriumsalzes des Mercaptobenzothiazols enthält, wird bei einer Temperatur von 40°C ein Mol Natrium-Monochloracetat zugegeben und man läßt dann noch für eine weitere Stunde bei derselben Temperatur reagieren. Die Lösung wird anschließend mit Salzsäure bis auf 5,0 - 6,0 pH angesäuert An diesem Punkt wird die Reaktionslösung filtriert, um Verunreinigungen abzutrennen. Zu der so gereinigten Lösung wird weitere Salzsäure gegeben, bis ein pH-Wert von 1 bis 3 erreicht ist Man erhält 2-Benzthiazolylthioessigsäure als weißes Pulver mit einem Schmelzpunkt von 155 - 156°C.To an aqueous solution containing one mole of the sodium salt of mercaptobenzothiazole, one mole of sodium monochloroacetate is added at a temperature of 40 ° C. and the mixture is then left to react at the same temperature for a further hour. The solution is then acidified to pH 5.0-6.0 with hydrochloric acid. At this point, the reaction solution is filtered to remove impurities. Further hydrochloric acid is added to the solution thus purified until a pH of 1 to 3 is reached. 2-Benzthiazolylthioacetic acid is obtained as a white powder with a melting point of 155-156 ° C.

Beispiel 3Example 3

Einer wäßrigen Lösung, die ein Mol des Natriumsalzes des Mercaptobenzthiazols enthält, wird langsam bei einer Temperatur von 50°C eine wäßrige Lösung von 1,2 Mol Natriummonochlorpropionat zugegeben.An aqueous solution containing 1.2 moles of the sodium salt of mercaptobenzothiazole is slowly added with an aqueous solution of 1.2 moles of sodium monochloropropionate at a temperature of 50 ° C.

Die Reaktion wird über zwei Stunden bei der Temperatur von 60 - 70°C fortgeführt, dann wird mit Salzsäure angesäuert, bis keine Ausfällungen mehr auftreten.The reaction is continued for two hours at a temperature of 60-70 ° C, then acidified with hydrochloric acid until no more precipitations occur.

Man erhält 2-Benzthiazolylthiopropionsäure als weißes Pulver, das nach Reinigung und Trocknung einen Schmelzpunkt von 145 - 147°C aufweist2-Benzthiazolylthiopropionic acid is obtained as a white powder which, after cleaning and drying, has a melting point of 145-147 ° C.

In der folgenden Tabelle sind einige wesentliche Kenndaten angegeben für das Triäthanolaminsalz der 2-Benzthiazolylthioessigsäure. Die Korrosionsschutzprüfung wurde durchgeführt gemäß der DIN-Norm 51360 (I und II). Die Abkürzungen haben folgende Bedeutung:

  • EK = 2-Benzthiazolylthioessigsäure
  • TEA = Triäthanolamin
  • RO = kein Rost
  • SO = kein pitting
    Figure imgb0002
    Figure imgb0003
    Figure imgb0004
The following table shows some key data for the triethanolamine salt of 2-benzothiazolylthioacetic acid. The corrosion protection test was carried out in accordance with DIN standard 51360 (I and II). The abbreviations have the following meaning:
  • EK = 2-benzthiazolylthioacetic acid
  • TEA = triethanolamine
  • RO = no rust
  • SO = no pitting
    Figure imgb0002
    Figure imgb0003
    Figure imgb0004

In den folgenden Test wurden die erfindungsgemäßen Korrosionsschutzmittel C und D zwei bereits bekannten Korrosionsschutzmitteln A und B vergleichend gegenübergestellt.

  • Als Vergleichssubstanzen wurden die Salze von zwei bekannten Säuren, die Isononansäure und die p-tert-butylbenzoesäure, verwendet. Die jeweilige Lösungen hatten folgende Zusammensetzung: A) 22 Gew. % Isononansäure 63 Gew. % Triäthanolamin 15 Gew. % Wasser
  • B) 25 Gew. % p-tert.-butylbenzoesäure 60 Gew. % Triäthanolamin 15 Gew. % Wasser
  • C) 31,5 Gew. % Verbindung gemäß Beispiel 1 oder 2 der vorliegenden Erfindung 53,5 Gew. % Triäthanolamin 15 Gew. % Wasser
  • D) 33 Gew. % Verbindung gemäß Beispiel 3 der vorliegenden Erfindung 52 Gew. % Triäthanolamin 15 Gew. % Wasser
In the following test, the anti-corrosion agents C and D according to the invention were compared with two previously known anti-corrosion agents A and B.
  • The salts of two known acids, isononanoic acid and p-tert-butylbenzoic acid, were used as reference substances. The respective solutions had the following composition: A) 22% by weight isononanoic acid 63% by weight triethanolamine 15% by weight water
  • B) 25% by weight of p-tert-butylbenzoic acid, 60% by weight of triethanolamine and 15% by weight of water
  • C) 31.5% by weight of compound according to Example 1 or 2 of the present invention, 53.5% by weight of triethanolamine and 15% by weight of water
  • D) 33% by weight of compound according to Example 3 of the present invention, 52% by weight of triethanolamine and 15% by weight of water

Die Ergebnisse sind in der folgenden Tabelle zusammengefaßt:

Figure imgb0005
The results are summarized in the following table:
Figure imgb0005

Der Korrosionsversuch an Kupfer und Aluminium wurde wie folgt durchgeführt. In vier Reagenzgläsern mit 100 cc. Wasser werden jeweils 1,5 g der Mischungen A, B, C und D zugegeben und in diese Lösungen werden Kupferfolien bzw. Aluminiumfolien nach DIN 1791 - E-CU 57 F30 mit den Abmessungen 2 x 12 x 75 mm eingetaucht Die Reagenzgläser werden geschlossen und für 20 Tage auf 20°C belassen. Am Ende des Versuches wird die von der Lösung aufgenommene Färbung beobachtet:

Figure imgb0006
The corrosion test on copper and aluminum was carried out as follows. In four test tubes with 100 cc. 1.5 g of mixtures A, B, C and D are added to water and copper foils or aluminum foils according to DIN 1791 - E-CU 57 F30 with the dimensions 2 x 12 x 75 mm are immersed in these solutions. The test tubes are closed and Leave at 20 ° C for 20 days. At the end of the experiment, the color taken up by the solution is observed:
Figure imgb0006

Claims (3)

1. Wäßrige Korrosionsschutzmittel enthaltend eine Verbindung der Formel
Figure imgb0007
wobei n eine Zahl von 1 bis 6 und M ein organisches Ammonium-lon bedeutet.
1st Aqueous corrosion protection agents containing a compound of the formula
Figure imgb0007
where n is a number from 1 to 6 and M is an organic ammonium ion.
2. Wäßrige Kühlschmiermittel enthaltend eine Verbindung nach Anspruch 1.2. Aqueous cooling lubricants containing a compound according to claim 1. 3. Wäßrige Korrosionsschutzmittel enthaltend 0,3 bis 5 Gew.-% einer Verbindung nach Anspruch 1.3. Aqueous corrosion protection agent containing 0.3 to 5 wt .-% of a compound according to claim 1.
EP86101564A 1985-02-19 1986-02-06 Aqueous anticorrosive agent containing an ammonium salt of 2-benzothia-zolylthiocarboxylic acid Withdrawn EP0192132A3 (en)

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IT19562/85A IT1185511B (en) 1985-02-19 1985-02-19 AQUEOUS ANTI-CORROSIVE AGENTS CONTAINING AN AMMONIC SALT OF 2-BENZOTHIAZOLYLTHIOCARBOXYLIC ACID

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