DE4041173A1 - 1-MONO or 1,3-SUBSTITUTED IMIDAZOLY SALTS AND THEIR BENZOANALOGS, METHOD FOR THE PRODUCTION AND THEIR USE - Google Patents

Abstract

The invention relates to 1-mono and 1,3-bis[omega-(1-oxo-alkyl/aryl-amino)-alkyl]-imidazolium salts and their benzo analogues of general formulae (I) to (IV) in which R<1> is an R<3>-CONH-(CH2)n radical with n = 2 or 3, R<2> is hydrogen or a saturated, straight or branched-chain alkyl radical with 1 to 6 C atoms or an unsaturated, straight or branched chanin alkyl radical with 2 to 6 C atoms; R<3> is a saturated, straight or branched chain alkyl radical with 1 to 29 C atoms or an unsaturated, straight or branched chain alkyl radical with 2 to 29 C atoms or an aromatic radical with 6 to 18 C atoms, and in which X is an anionic counter-ion from the group formed by halides, sulphonates, sulphates, carbonates, phosphates or carboxylic acid anions with 1 to 30 C atoms, and their use as corrosion protection, antimicrobial and brightening agents.

Description

The invention relates to new substituted imidazolium salts and whose benzo analogues of the general formulas (I) to (IV), a Ver drive to make these connections through ring opening craze tion of 2-alkyl-1,3-oxazolines with imidazolium salts or their Benzo analogues and the use of the compounds of the general Formulas I to IV as anti-corrosion agents.

In the drinking water supply and in heating and cooling circuits fin the metallic materials, especially copper, as is known wide application. As is well known, however, lead to corro damage from aggressive oxygen over a long period of time significant corrosion damage. For these reasons, you bet generally environmentally friendly and inexpensive inhibitors one, the inaccessible places even in the form of aqueous solutions can temporarily protect against corrosion.

In practice, aromatic corrosion inhibitors have been found Heterocycles such as benzotriazole, tolyltriazole, benzimidazole derivatives or mercaptobenzothiazole (see J. Penninger, K. Wippermann and J. W. Schultze, "Materials and Corrosion", Vol 38 (1987), page 649) proven. Good corrosion inhibitors usually form multi-molecular cover layers on the metal surface, so that the  Oxide formation on the metal surface is suppressed. The inhibi Gate effect is usually determined by the protection factor S (%) = 100 × (1-a / b), where a and b the weight loss in inhibi Specify a gate-containing or inhibitor-free solution.

However, the corrosion inhibitors mentioned above have made the decision The disadvantage that they do not meet the toxicological requirements have grown and due to their poor water solubility cannot be used in all pH ranges.

In the applicant's German patent application DE-A-29 34 461 3-Amino-5-alkyl-1,2,4-triazoles are already used as corrosion inhibitors bitters for non-ferrous metals in aqueous systems in a pH range from 6 to 10.

Furthermore, from the German interpretation DE-B-20 03 175 Use of 2-alkylimidazoles or their acid addition salts as a corrosion protection agent for copper and copper alloy surfaces known areas. Among other things, in this interpretation assumed that in particular imidazoles, the long straight-chain Bear alkyl groups in the 2-position, which have the ability, Mi cellen form and consequently also a satisfactory have a corrosion-inhibiting effect.

From European patent specification EP-B-2 00 947 1,3- Di-substituted imidazolium salts are known, which are either by Um setting of amino-substituted imidazoles with aldehydes or Ke tone in the form of a condensation reaction or by M-alkylation of imidazole derivatives. The ones described there Compounds are found especially in pharmaceuticals as anthelmint effective agents used.

The object of the present invention was now a new corrosion protection agent on imidazolium or benzimidazo lium basis that is easy to use can be produced, sufficient water solubility guaranteed and can be used over the entire pH range.

The present invention accordingly relates to 1-mono- and 1,3-bis [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts and de ren benzo analogues of the general formulas (I) to (IV)

in which R ^{1 represents} an R ³ -CONH-CH₂-CH₂ radical,
in which R ^{2 represents} hydrogen or a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 6 carbon atoms,
in which R ^{3 represents} a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 29 carbon atoms or an aromatic radical having 6 to 18 carbon atoms and
in which X is an anionic counterion, from the group formed by halides, sulphates, carbonates, phosphates or carboxylic acid anions having 1 to 30 carbon atoms.

In the system of the description of the invention correspond to the 1-mo no [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts of the general Formula (I), the 1,3-bis [2- (1-oxoalkyl) aminoethyl] imidazolium Salts of the general formula (II) and the associated benzo analogs of the general formulas (III) and (IV).

Another object of the present invention is a method ren for the production of imidazolium salts or their benzo analogs of the general formulas (I) to (IV), which is characterized by net is that you unsub with 2-alkyl-1,3-oxazolines in the 1,3-position substituted imidazolium salts or their benzo analogs in one organic solvents reacted by ring opening reaction.

Another object of the present invention relates to Use of the compounds of the general formulas (I) to (IV) as an anti-corrosion agent.

Compared to the known corrosion inhibitors, the new ones open up Compounds according to the invention an inexpensive, environmentally compatible and alternative possibility metal surfaces, for example in Water circulation systems to protect against corrosion damage.

The process according to the invention for the preparation of the compounds of the general formulas (I) to (IV) by ring opening reaction of 2-alkyl-1,3-oxazolines with imidazolium salts or their benzo analog is despite the already known ring opening reaction of Oxazolines with primary or secondary open chain amines  (see M. J. Fazio, Journal of Organic Chemistry, Volume 49, p. 4889-4893, 1984) as an interesting new variant for the synthesis of To understand N-substituted, basic nitrogen heterocycles.

In a preferred embodiment of the present invention in the compounds of the general formulas (I) to (IV) R ^{2 is} hydrogen or methyl, R ^{3 is} a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 21 C atoms, preferably 7 to 11 carbon atoms, or a phenyl radical and X for a halide or carboxylic acid anion.

For the purposes of the present invention, the radical R ^{3 is} identical to the alkyl radical from the 2-alkyl-1,3-oxazolines, so that the properties of the compounds according to the invention of the general are selected by selecting the corresponding 2-alkyl-1,3-oxazoline Formulas (I) to (IV), in particular water solubility and corrosion-inhibiting properties, can be varied in a targeted manner.

Examples of the compounds of the general formulas (I) to (IV) according to the invention are:
1,3-bis [2- (1-oxododecyl) aminoethyl] imidazolium chloride,
1,3-bis [2- (1-oxo-decyl) amino-ethyl] imidazolium chloride,
1,3-bis [2- (1-oxo-octyl) amino-ethyl] imidazolium chloride,
1,3-bis [2- (benzoyl) amino-ethyl] imidazolium chloride,
1-mono [2- (1-oxododecyl) amino-ethyl] imidazolium chloride,
1,3-bis [2- (1-oxo-decyl) amino-ethyl] -2-methyl-imidazolium chloride,
1,3-bis [2- (1-oxo-decyl) amino-ethyl] benzimidazolium chloride.

For the purposes of the invention, the following are particularly preferred:
1,3-bis [2- (1-oxododecyl) aminoethyl] imidazolium chloride,
1,3-bis [2- (1-oxo-decyl) amino-ethyl] imidazolium chloride,
1-mono [2- (1-oxododecyl) amino-ethyl] imidazolium chloride.

In the general embodiment of the method according to the invention Rens for the preparation of the compounds of the general formulas (I) to (IV), the 2-alkyl-1,3-oxazolines are placed in the 1,3-position unsubstituted imidazolium salts or their benzo analogues in a molar ratio of 1: 1 to 2: 1 µm. According to the invention Imidazolium salts or their benzo analogs, especially imidazolhy drochloride, 2-methylimidazole hydrochloride, in 4- and 5-position substituted imidazole hydrochloride, benzimidazole hydrochloride, 2-methylbenzimidazole hydrochloride and / or substituted benzimida zolhydrochloride used.

In a preferred embodiment of the Ver The 1-mono- [2- (1-oxo-alkyl) amino-ethyl] imidazo lium salts or their benzo analogs of the general formulas (I) and (III) by reacting 2-alkyl-1,3-oxazolines with imidazolium salts or their benzo analogues in a molar ratio of about 1: 1 posed. If desired, the molar ratio between the 2- Alkyl-1,3-oxazolines and the imidazolium salts or their benzo can be varied analogously in the range from 0.8: 1 to 1.2: 1.

In a further preferred embodiment of the fiction Process for the preparation of the compounds of the general Formulas (I) to (IV) are the 1,3-bis [2- (1-oxo-alkyl) amino ethyl] imidazolium salts or their benzo analogues of the general Formulas (II) and (IV) by reaction of 2-alkyl-1,3-oxazolines with imidazolium salts or their benzo analogues in a molar ratio of Made 2: 1. For the purposes of the present invention, the mol relationship between the 2-alkyl-1,3-oxazolines and the imidazo  lium salts or their benzo analogues if desired in the range of 1.8: 1 to 2.2: 1 can be varied.

In the general embodiment of the method according to the invention Rens for the preparation of the compounds of the general formulas (I) bis (IV) 2-alkyl-1,3-oxazolines with an alkyl radical are the best Starting from 1 to 29 carbon atoms, preferably 7 to 11 carbon atoms puts. 2-Heptyl-1,3-oxazoline, 2- Octyl-1,3-oxazoline, 2-nonyl-1,3-oxazoline, 2-decyl-1,3-oxazoline and / or 2-undecyl-1,3-oxazoline used.

For the purposes of the present invention, the Ver drive in such a way that the ring opening reaction with heating, preferably under reflux, in straight-chain or branched chain alcohols with 1 to 6 carbon atoms. He According to the invention, straight-chain or branched-chain alcohols get methanol, ethanol, propanol, isobutanol, butanol, pen tanol and hexanol and their branched chain isomers are used are, with isopropanol being particularly preferred.

In a general embodiment of the present invention the compounds of the general formulas according to the invention (I) to (IV) as anti-corrosion agents for copper or copper Yield surfaces used in water-bearing systems.

The compounds of the general Formulas (I) to (IV) in general for drinking water supply or in heating and cooling circuits in the form of an aqueous solution with an application concentration of 1 to 100 ppm, preferably 5 up to 20 ppm. In principle, higher concentrations can also be used  tions are used, but only for economic reasons are requested in exceptional cases.

For the purposes of the present invention, the compounds of general formulas (I) to (IV) in the form of an aqueous solution a pH of 1 to 14, preferably from 4 to 10, used.

The operating temperature of the anti-corrosion agents according to the invention can generally be between 0 ° and about 200 ° C, each but generally room temperature is preferred.

The present invention will now be described in detail with reference to the fol examples are documented.

Examples General procedure for the preparation of 1,3-bis [2- (1-oxo alkyl) amino-ethyl] imidazolium salts

In a 250 ml stirring apparatus, 0.4 mol of 2-alkyl-1,3-oxazoline submitted in 50 ml of isopropanol, with stirring and nitrogen inlet tion heated at reflux and a solution of 0.2 mol imidazo lium hydrochloride in 100 ml isopropanol added dropwise in 30 min. To The mixture was heated for 6 hours under reflux and left to stand overnight Approach concentrated and the residue from ethyl acetate / iso propanol (30: 1) recrystallized.

The compound given in Table 1 is obtained in an analogous manner fertilize.  

Table 1

1-Mono- or 1,3-bis [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts and their benzo analogues by ring opening reaction

Corrosion protection test on a copper surface according to DIN 51 360/2

Test solution B (pH = 9; Cu, Zn)
11.41 g CaCl₂ × 2 H₂O
3.3 g MgSO₄ × 7 H₂O, 330 ppm Cl
4.56 g NaCl, 50 ppm SO₄
25 l dist. H₂O

Test solution C (pH = 4; Cu, Zn)
11.41 g CaCl₂ × 2 H₂O
3.3 g MgSO₄ × 7 H₂O, 500 ppm Cl
11.54 g NaCl, 50 ppm SO₄
25 l dist. H₂O

Test body: E-Cu; Coupon area: 25.7 cm²

Test temperature: 20 ° C

Test duration: 24 h

Stirring speed: 80 U / Min

Standard: benzotriazole

Buffer:
pH 4; Na acetate / acetic acid
pH 9; Ammonium chloride / ammonia

Pretreatment of the Cu coupon:

• a) degrease with an acetone-soaked linen cloth
• b) 30 min. in dilute hydrochloric acid (1 part conc. HCl / 4 parts H₂O)
• c) Swing 2x in a water bath  
• d) Clean with linen cloth soaked in acetone
• e) weigh.

Test execution

In 800 ml of test water and 30 ml of buffer solution (pH 4 or pH 9) the corrosion inhibitor to be investigated (Examples 1 to 7) in a concentration of 5 ppm and the Cu coupon completely immersed in the liquid. After 24 h the corrosion place on the Cu coupon rinsed under light brushing, the coupon swirled in acetone, dried, weighed and in relation to the Blank value (water) set.

Experiment evaluation:
The corrosion protection (in%) then results from the formula:

In this way the compounds from the examples provided a double determination the corrosion specified in Table 2 protection values.  

Table 2

Corrosion protection values S of the examples according to the invention

Claims (12)

1. 1-mono- and 1,3-bis [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts and their benzo analogues of the general formulas (I) to (IV) in which R ^{1 represents} an R ³ -COMH-CH₂-CH₂ radical,
in which R ^{2 represents} hydrogen or a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 6 carbon atoms,
in which R ^{3 is} a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 29 carbon atoms or an aromatic radical having 6 to 18 carbon atoms and
in which X is an anionic counterion, from the group formed by halides, sulfates, carbonates, phosphates and / or carboxylic acid anions having 1 to 30 C atoms. 2. Compounds according to claim 1, characterized in that in the compounds of general formulas (I) to (IV) R ² for hydrogen or methyl, R ³ for a saturated or unsaturated, straight-chain or branched-chain alkyl radical having 1 to 21 C- Atoms, preferably 7 to 11 carbon atoms, or a phenyl radical and X represents a halide or carboxylic acid anion. 3. Process for the preparation of imidazolium salts or their Benzo analogues of the general formulas (I) to (IV), thereby ge indicates that 2-alkyl-1,3-oxazolines by ring opening reaction with imidazo unsubstituted in the 1,3-position lium salts or their benzo analogues in an organic solvent implement means. 4. The method according to claim 3, characterized in that one the 2-alkyl-1,3-oxazolines with unsubstituted 1,3-position Imidazolium salts or their benzo analogues in a molar ratio from 1: 1 to 2: 1. 5. The method according to claims 3 and 4, characterized in that the 1-mono- [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts or their benzo analogues of the general formula (I) and (III) by reacting 2-alkyl-1,3-oxazolines with imidazo lium salts or their benzo analogs in a molar ratio of 1: 1 receives. 6. The method according to claims 3 to 5, characterized in that the 1,3-bis [2- (1-oxo-alkyl) amino-ethyl] imidazolium salts or their benzo analogues of the general formulas (II) and (IV) by reaction of 2-alkyl-1,3-oxazolines with imidazo  lium salts or their benzo analogs in a molar ratio of 2: 1 receives. 7. The method according to claims 3 to 6, characterized in that that as 2-alkyl-1,3-oxazoline compounds with an Al kylrest, consisting of 1 to 29 carbon atoms, preferably 7 to 11 carbon atoms. 8. The method according to claims 3 to 7, characterized in that that the ring opening reaction with heating, preferably under reflux, in straight-chain or branched-chain alcohols get through with 1 to 6 carbon atoms, preferably isopropanol leads. 9. Use of the compounds of the general formulas (I) to (IV) as an anti-corrosion agent. 10. Embodiment according to claim 9, characterized in that the compounds of the general formulas (I) to (IV) as Corrosion protection agent for copper or copper alloy surfaces surfaces in water-bearing systems. 11. Embodiment according to claim 9 and 10, characterized net that the compounds of general formulas (I) to (IV) in the form of an aqueous solution in a concentration of 1 to 100 ppm, preferably 5 to 20 ppm, as corrosion uses protective agents. 12. Embodiment according to claim 9 to 11, characterized in net that the compounds of general formulas (I) to  (IV) in the form of an aqueous solution at a pH of 1 to 14, preferably 4 to 10, is used.