Compositions – Fluent dielectric – N-containing
Patent
1993-02-02
1994-06-07
Lieberman, Paul
Compositions
Fluent dielectric
N-containing
25217419, 25217423, 25217425, 252548, 252DIG11, 562564, 562565, 562568, 562571, C11D 333, C07C22714, C07C22924
Patent
active
053187261
DESCRIPTION:
BRIEF SUMMARY
This invention relates to 3-hydroxy-2,2'-iminodisuccinic acid and soluble salts thereof, to a process for their production and to their use as complexing agents in detergents.
In addition to the obvious need for a high complexing capacity, complexing agents intended for use in modern detergents are increasingly having to satisfy requirements relating to ecologically safe behavior.
DE-OS 22 41 134 describes N-substituted aminohydroxysuccinic acid derivatives which have a more or less high complexing capacity, particularly for alkaline earth metal ions, according to the type and number of substituents bearing carboxyl groups at the N atom. Compounds such as these, which are distinguished by high complexing capacity, show relatively poor degradability whereas more readily degradable products have a comparatively poor complexing capacity.
Accordingly, there is still a need to develop a readily biodegradable and powerful complexing agent.
It has now surprisingly been found that 3-hydroxy-2,2'-iminodisuccinic acid and soluble salts thereof show both a high complexing capacity for the alkali metal ions responsible for the hardness of water and for heavy metal ions and also ready biodegradability and exhibit unexpectedly superior properties through this combination of complexing capacity and biodegradability.
In the context of the invention, soluble substances are understood to be compounds which dissolve in water at 20.degree. C. in a quantity of more than 0.1 gram per liter.
The soluble salts of 3-hydroxy-2,2'-iminodisuccinic acid are preferably those which contain cations from the group of ammonium and alkali metal ions as cations, the ammonium ions preferably being those having the general structural formula R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+, in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent hydrogen, C.sub.1-12 alkyl radicals or hydroxysubstituted C.sub.2-3 alkyl radicals. One, two, three or all four carboxylic acid groups of the 3-hydroxy-2,2'-iminodisuccinic acid may be present in the salt form. Accordingly, the compounds in question are compounds corresponding to general formula (I) ##STR1## in which A, B, Y and Z independently of one another represent a cation, preferably from the group consisting of hydrogen, ammonium and alkali metal ions, the ammonium ions belonging to those having the general structural formula R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+ in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent hydrogen, C.sub.1-12 alkyl radicals or hydroxy-substituted C.sub.2-3 alkyl radicals.
By comparison with the compounds according to DE-OS 22 41 134, it has been found that the 3-hydroxy-2,2'-iminodisuccinic acid according to the invention shows better biodegradability and a higher complexing capacity, particularly at relatively high temperatures, for example 70.degree. to 98.degree. C. (Table 1, Table 2).
The 3-hydroxy-2,2'-iminodisuccinic acid or salts thereof corresponding to formula (I) are prepared by reaction of aspartic acid with epoxysuccinic acid, preferably in molar ratios of 1.05:1 to 1:1.05. The reaction is preferably carried out in aqueous or at least predominantly aqueous medium, the residual solvent consisting of organic compounds inert under the reaction conditions, more particularly methanol, ethanol and/or dioxane. The reaction is preferably carried out under substantially neutral to mildly basic conditions, i.e. in the presence of alkalis, preferably in the form of aqueous solutions of alkali metal or ammonium hydroxides, so that the acid groups of the reactants are present at least partly and preferably completely in the form of carboxylate anions, preferably as alkali metal or ammonium carboxylates. The ammonium hydroxide is preferably selected from compounds corresponding to the general formula R.sup.1 R.sup.2 R.sup.3 R.sup.4 N.sup.+ OH.sup.-, in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently of one another represent hydrogen, C.sub.1-12 alkyl radicals or hydroxysubstituted C.sub.2-3 alkyl radicals.
REFERENCES:
patent: 3637511 (1972-01-01), Yang
patent: 3929874 (1975-12-01), Beermann et al.
patent: 5183590 (1993-02-01), Carter et al.
Payne, G. B. and Williams, P. H., "Reactions of Hydrogen Peroxide, IV. Sodium Tungstate Catalyzed Epoxidation of .alpha.,.beta.-Unsaturated Acids", J. Org. Chem., vol. 24, 1959, pp. 54-55.
OECD-Screenting-Test (EEC Directive 79/831, Annex V, Part C, 5.2, May 12, 1981.
Zahn, R. and Wellens, H., Chemiker Zeilung, vol. 98, 1974, pp. 228-252.
Blum Helmut
Riebe Hans-Juergen
Rossmaier Henry
Steber Josef
Henkel Kommanditgesellschaft auf Aktien
Hertzog A.
Jaeschke Wayne C.
Lieberman Paul
Millson Jr. Henry E.
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