Succinic acid derivative degradable chelants, uses and compositions thererof

Solutions comprising at least one polyamino disuccinic acid and one or more polyamino monosuccinic acids are useful in gas conditioning (preferably as the iron chelate). The copper chelates are also useful in electroless copper plating. Another aspect of the invention includes the use of the aminosuccinic acid mixtures in laundry detergent compositions.

This application claims the benefit of U.S. Provisional Application No. 
60/003,042, filed Aug. 30, 1995. This invention relates to chelants, 
particularly uses of certain synergistic combinations of degradable 
chelants. 
BACKGROUND OF THE INVENTION 
Chelants or chelating agents are compounds which form coordinate covalent 
bonds with a metal ion to form chelates. Chelates are coordination 
compounds in which a central metal atom is bonded to two or more other 
atoms in at least one other molecule (called ligand) such that at least 
one heterocyclic ring is formed with the metal atom as part of each ring. 
Chelants are used in a variety of applications including food processing, 
soaps, detergents, cleaning products, personal care products, 
pharmaceuticals, pulp and paper processing, gas conditioning, water 
treatment, metalworking and metal plating solutions, textile processing 
solutions, fertilizers, animal feeds, herbicides, rubber and polymer 
chemistry, photofinishing, and oil field chemistry. Some of these 
activities result in chelants entering the environment. For instance, 
agricultural uses or detergent uses may result in measurable quantities of 
the chelants being in water. It is, therefore, desirable that chelants 
degrade after use. 
Biodegradability, that is susceptibility to degradation by microbes, is 
particularly useful because the microbes are generally naturally present 
in environments into which the chelants may be introduced. Commonly used 
chelants like EDTA (ethylenediamine tetraacetic acid) are biodegradable, 
but at rates somewhat slower and under conditions considered by some to be 
less than optimum. (See, Tiedje, "Microbial Degradation of 
Ethylenediaminetetraacetate in Soils and Sediments," Applied Microbiology, 
Aug. 1975, pp. 327-329.) It would be desirable to have a chelating agent 
which degrades faster than EDTA or other commonly used chelants. 
Biodegradation of chelants is of particular interest in many metal ion 
control applications. Examples include use of chelants in the following 
areas: electroless copper plating, prevention or removal of undesirable 
iron deposits, removal of organic stains from fabrics, scrubbing of 
H.sub.2 S and/or NO.sub.x from gas streams via metal chelates, stabilizing 
peroxide in cellulosic bleaching systems, and others. However, finding a 
commercially useful biodegradable chelant for these applications has been 
difficult. The chelating agents that are most useful generally do not 
biodegrade in a desirable time (e.g. ethylenediaminetetraacetic acid, 
N-hydroxyethylethlyenediaminetriacetic acid, diethylenetriaminepentaacetic 
acid, cyclohexanediaminetetraacetic acid, and propylenediaminetetraacetic 
acid) all biodegrade less than 60% in 28 days using the OECD 301 B 
Modified Sturm Test. 
It would be desirable to have a chelant, or a mixture of chelants, useful 
in metal ion control processes, where such chelant or mixture of chelants 
is greater than about 60 percent biodegradable within less than 28 days 
according to the OECD 301B Modified Sturm Test. 
SUMMARY OF THE INVENTION 
A combination of chelants, or metal chelates thereof, comprising at least 
one polyamino disuccinic acid and one or more polyamino monosuccinic 
acids, or salts thereof have been found to be excellent for use in metal 
ion control applications where enhanced biodegradability is desired. It 
has been found that certain mixtures of chelants display unexpected metal 
ion control performance and ease of biodegradability 
In one aspect, the invention includes methods of electroless plating using 
various metals (especially copper) complexed with a mixture of chelants 
comprising at least one polyamino disuccinic acid and one or more 
polyamino monosuccinic acids, or salts thereof. It includes a method of 
electroless deposition of copper upon a non-metallic surface receptive to 
the deposited copper including a step of contacting the non-metallic 
surface with an aqueous solution comprising a soluble copper salt and at 
least one polyamino disuccinic acid and one or more polyamino monosuccinic 
acids, or salts thereof. Also included is a method of electroless copper 
plating which comprises immersing a receptive surface to be plated in an 
alkaline, autocatalytic copper bath comprising water, a water soluble 
copper salt, and at least one polyamino disuccinic acid and one or more 
polyamino monosuccinic acids, or salts thereof as the complexing agents 
for cupric ion. Additionally, there is an improvement in a process for 
plating copper on non-metallic surfaces, only selected portions of which 
have been pretreated for the reception of electroless copper, by immersing 
the surface in an autocatalytic alkaline aqueous solution comprising, in 
proportions capable of effecting electroless deposition of copper, a water 
soluble copper salt, a complexing agent for cupric ion, and a reducing 
agent for cupric ion, the improvement comprising using as the complexing 
agent for cupric ion, at least one polyamino disuccinic acid and one or 
more polyamino monosuccinic acids, or salts thereof. The invention 
includes a bath for the electroless plating of copper which comprises 
water, a water soluble copper salt, at least one polyamino disuccinic acid 
and one or more polyamino monosuccinic acids, or salts thereof as 
complexing agents for cupric ions, sufficient alkali metal hydroxide to 
result in a pH of from about 10 to about 14, and a reducing agent. 
Another aspect of the invention includes a method for removing iron oxide 
deposits or organic stains from a surface including a step of contacting 
the deposits or stains with a solution comprising at least one polyamino 
disuccinic acid and one or more polyamino monosuccinic acids, or salts 
thereof. 
Yet another aspect of the invention involves gas conditioning. In this 
aspect the invention includes a process of removing H.sub.2 S from a fluid 
comprising contacting said fluid with an aqueous solution at a pH suitable 
for removing H.sub.2 S wherein said solution contains at least one higher 
valence polyvalent metal chelate of at least one polyamino disuccinic acid 
and one or more polyamino monosuccinic acids, or salts thereof. Another 
aspect of the gas conditioning invention includes a process of removing 
NO.sub.x from a fluid comprising contacting the fluid with an aqueous 
solution of at least one lower valence state polyvalent metal chelate of 
at least one polyamino disuccinic acid and one or more polyamino 
monosuccinic acids, or salts thereof. 
The present invention is also to a laundry detergent composition comprising 
(a) from about 1% to about 80% by weight of a detergent surfactant 
selected from nonionic, anionic, cationic, zwitterionic, and ampholytic 
surfactants and mixtures thereof; (b) from about 5% to about 80% by weight 
of at least one detergent builder; and (c) from about 0.1% to about 15% by 
weight of a combination of chelants comprising at least one polyamino 
disuccinic acid and one or more polyamino monosuccinic acids, or salts 
thereof. 
In another aspect, the present invention is a liquid laundry detergent 
composition comprising (a) from about 10% to about 50% by weight of a 
detergent surfactant selected from nonionic, anionic, cationic, 
zwitterionic, and ampholytic surfactants and mixtures thereof; (b) from 
about 10% to about 40% by weight of at least one detergent builder; and 
(c) from about 0.1% to about 10% by weight of a combination of chelants 
comprising at least one polyamino disuccinic acid and one or more 
polyamino monosuccinic acids, or salts thereof. 
The present invention is also to a granular laundry composition comprising 
(a) from about 5% to about 50% by weight of a detergent surfactant 
selected from nonionic, anionic, cationic, zwitterionic, and ampholytic 
surfactants and mixtures thereof; (b) from about 10% to about 40% by 
weight of at least one detergency builder; and (c) from about 0.1% to 
about 10% by weight of a combination of chelants comprising at least one 
polyamino disuccinic acid and one or more polyamino monosuccinic acids, or 
salts thereof. 
The above laundry compositions are used in a method of laundering fabrics 
comprising contacting a fabric with an aqueous solution of the above noted 
laundry detergent compositions. 
The present invention is also to a composition for chelating a metal 
comprising at least one polyamino discuccinic acid and at least one 
polyamino monosuccinic acid, or salts thereof. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention is to the use of a mixture of at least one polyamino 
disuccinic acid and one or more polyamino monosuccinic acids, also 
referred to herein as succinic acid mixtures. As used herein the term 
succinic acid includes salts thereof. It has been unexpectedly found that 
when a mixture of such compounds is used to chelate a metal ion, such as 
iron, said mixtures show a greater ability to chelate the metal ion and 
such complexes have a greater stability than what would be expected from 
the sum of the individual compounds. Such mixtures also show an unexpected 
increase in biodegradability as measured by the OECD 301B Modified Sturm 
Test. 
Polyamino disuccinic acids are compounds having two or more nitrogen atoms 
wherein 2 of the nitrogens are bonded to a succinic acid (or salt) group, 
preferably only two nitrogen atoms each have one succinic acid (or salt) 
group attached thereto. The compound has at least 2 nitrogen atoms, and 
due to the commercial availability of the amine, preferably has no more 
than about 10 nitrogen atoms, more preferably no more than about 6, most 
preferably 2 nitrogen atoms. Remaining nitrogen atoms most preferably are 
substituted with hydrogen atoms. More preferably, the succinic acid groups 
are on terminal nitrogen atoms, most preferably each of which nitrogens 
also has a hydrogen substituent. Because of steric hindrance of two 
succinic groups on one nitrogen, it is preferred that each nitrogen having 
a succinic group has only one such group. Remaining bonds on nitrogens 
having a succinic acid group are preferably filled by hydrogens or alkyl 
or alkylene groups (linear, branched or cyclic including cyclic structures 
joining more than one nitrogen atom or more than one bond of a single 
nitrogen atom, preferably linear) or such groups having ether or thioether 
linkages, all of preferably from I to about 10 carbon atoms, more 
preferably from 1 to about 6, most preferably from 1 to about 3 carbon 
atoms, but most preferably hydrogen. More preferably, the nitrogen atoms 
are linked by alkylene groups, preferably each of from about 2 to about 12 
carbon atoms, more preferably from about 2 to about 10 carbon atoms, even 
more preferably from about 2 to about 8, most preferably from about 2 to 
about 6 carbon atoms. The polyamino disuccinic acid compound preferably 
has at least about 10 carbon atoms and preferably has at most about 50, 
more preferably at most about 40, most preferably at most about 30 carbon 
atoms. The term "succinic acid" is used herein for the acid and salts 
thereof; the salts include metal cation (e.g. potassium, sodium) and 
ammonium or amine salts. Polyamino disuccinic acids useful in the practice 
of the invention are unsubstituted (preferably) or inertly substituted, 
that is substituted with groups that do not undesirably interfere with the 
activity of the polyamino disuccinic acid in a selected application. Such 
inert substituents include alkyl groups (preferably of from 1 to about 6 
carbon atoms); aryl groups including arylalkyl and alkylaryl groups 
(preferably of from 6 to about 12 carbon atoms), and the like with alkyl 
groups preferred among these and methyl and ethyl groups preferred among 
alkyl groups. Inert substituents are suitably on any portion of the 
molecule, preferably on carbon atoms, more preferably on alkylene groups, 
e.g. alkylene groups between nitrogen atoms or between carboxylic acid 
groups, most preferably on alkylene groups between nitrogen groups. 
Preferred polyamino disuccinic acids include 
ethylenediamine-N,N'-disuccinic acid, diethylenetriamine-N,N"-disuccinic 
acid, triethylenetetraamine-N,N'"-disuccinic acid, 
1,6-hexamethylenediamine N,N'-disuccinic acid, 
tetraethylenepentamine-N,N""-disuccinic acid, 
2-hydroxypropylene-1,3-diamine-N,N'-disuccinic acid, 
1,2-propylenediamine-N,N'-disuccinic acid, 
1,3-propylenediamine-N,N'-disuccinic acid, 
cis-cyclohexanediamine-N,N'-disuccinic acid, 
trans-cyclohexanediamine-N,N'-disuccinic acid, and 
ethylenebis(oxyethylenenitrilo)-N,N'-disuccinic acid. The preferred 
polyamino disuccinic acid is ethylenediamine-N,N'-disuccinic acid. 
Such polyamino disuccinic acids can be prepared, for instance, by the 
process disclosed by Kezerian et al. in U.S. Pat. No. 3,158,635 which is 
incorporated herein by reference in its entirety. Kezerian et al disclose 
reacting maleic anhydride (or ester or salt) with a polyamine 
corresponding to the desired polyamino disuccinic acid under alkaline 
conditions. The reaction yields a number of optical isomers, for example, 
the reaction of ethylenediamine with maleic anhydride yields a mixture of 
three optical isomers R,R!, S,S! and S,R! ethylenediamine disuccinic 
acid (EDDS) because there are two asymmetric carbon atoms in 
ethylenediamine disuccinic acid. These mixtures are used as mixtures or 
alternatively separated by means within the state of the art to obtain the 
desired isomer(s). Alternatively, S,S! isomers are prepared by reaction 
of such acids as L-aspartic acid with such compounds as 1,2-dibromoethane 
as described by Neal and Rose, "Stereospecific Ligands and Their Complexes 
of Ethylenediaminedisuccinic Acid", Inorganic Chemistry, v. 7. (1968), pp. 
2405-2412. 
Polyamino monosuccinic acids are compounds having at least two nitrogen 
atoms to which a succinic acid (or salt) moiety is attached to one of the 
nitrogen atoms. Preferably the compound has at least 2 nitrogen atoms, and 
due to the commercial availability of the amine, preferably has no more 
than about 10 nitrogen atoms, more preferably no more than about 6, most 
preferably 2 nitrogen atoms. Remaining nitrogens atoms, those which do not 
have a succinic acid moiety attached, preferably are substituted with 
hydrogen atoms. Although the succinic acid moiety may be attached to any 
of the amines, preferably the succinic acid group is attached to a 
terminal nitrogen atom. By terminal it is meant the first or last amine 
which is present in the compound, irrespective of other substituents. The 
remaining bonds on the nitrogen having a succinic acid group are 
preferably filled by hydrogens or alkyl or alkylene groups (linear, 
branched or cyclic including cyclic structures joining more than one 
nitrogen atom or more than one bond of a single nitrogen atom, preferably 
linear) or such groups having ether or thioether linkages, all of 
preferably from I to about 10 carbon atoms, more preferably from 1 to 
about 6, most preferably from 1 to about 3 carbon atoms, but most 
preferably hydrogen. Generally the nitrogen atoms are linked by alkylene 
groups, each of from about 2 to about 12 carbon atoms, preferably from 
about 2 to about 10 carbon atoms, more preferably from about 2 to about 8, 
and most preferably from about 2 to about 6 carbon atoms. The polyamino 
monosuccinic acid compound preferably has at least about 6 carbon atoms 
and preferably has at most about 50, more preferably at most about 40, and 
most preferably at most about 30 carbon atoms. Polyamino monosuccinic 
acids useful in the practice of the invention are unsubstituted 
(preferably) or inertly substituted as described above for polyamino 
disuccinic acid compounds. 
Preferred polyamino monosuccinic acids include ethylenediamine monosuccinic 
acid, diethylenetriamine monosuccinic acid, triethylenetetraamine 
monosuccinic acid, 1,6-hexamethylenediamine monosuccinic acid, 
tetraethylenepentamine monosuccinic acid, 2-hydroxypropylene-1,3-diamine 
monosuccinic acid, 1,2-propylenediamine monosuccinic acid, 
1,3-propylenediamine monosuccinic acid, cis-cyclohexanediamine 
monosuccinic acid, trans-cyclohexanediamine monosuccinic acid and 
ethylenebis(oxyethylenenitrilo) monosuccinic acid. The preferred polyamino 
monosuccinic acid is ethylenediamine monosuccinic acid. 
Such polyamino monosuccinic acids can be prepared for instance, by the 
process of Bersworth et al. in U.S. Pat. No. 2,761,874, the disclosure of 
which is incorporated herein by reference, and as disclosed in Jpn. Kokai 
Tokkyo Koho JP 57,116,031. In general, Bersworth et al. disclose reacting 
alkylene diamines and dialkylene triamines under mild conditions with 
maleic acid esters under mild conditions (in an alcohol) to yield amino 
derivatives of N-alkyl substituted aspartic acid. The reaction yields a 
mixture of the R and S isomers. 
In a preferred embodiment, when the chelant solution contains a mixture of 
a polyamino disuccinic acid and a polyamino monosuccinic acid, it is 
preferred that the polyamino substituent of the polyamino disuccinic acid 
and the polyamino monosuccinic acid are the same. Thus by way of example, 
if the polyamino disuccinic acid is ethylenediamine-N-N'-disuccinic acid, 
the polyamine monosuccinic acid is ethylenediamine monosuccinic acid. 
The invention includes the use of iron complexes of a polyamino disuccinic 
acid and a polyamino monosuccinic acid in abatement of hydrogen sulfide 
and other acid gases and as a source of iron in plant nutrition. Similarly 
other metal complexes such as the copper, zinc and manganese complexes 
supply those trace metals in plant nutrition. The ferrous complexes are 
also useful in nitrogen oxide abatement. 
Iron complexes used in the present invention are conveniently formed by 
mixing an iron compound with an aqueous solution of the succinic acid 
mixtures, or salts thereof. The pH values of the resulting iron chelate 
solutions are preferably adjusted with an alkaline material such as 
ammonia solution, sodium carbonate, or dilute caustic (NaOH). Water 
soluble iron compounds are conveniently used. Exemplary iron compounds 
include iron nitrate, iron sulfate, and iron chloride. The final pH values 
of the iron chelate solutions are preferably in the range of about 4 to 9, 
more preferably in the range of about 5 to 8. When an insoluble iron 
source, such as iron oxide, is used, the succinic acid compounds are 
preferably heated with the insoluble iron source in an aqueous medium at 
an acidic pH. The use of ammoniated amino succinic acid solutions are 
particularly effective. Ammoniated amino succinic acid chelants are 
conveniently formed by combining aqueous ammonia solutions and aqueous 
solutions or slurries of amino succinic acids in the acid (rather than 
salt) form. 
Succinic acid mixtures are effective as chelants especially for metals such 
as iron and copper. Effectiveness as a chelant is conveniently measured by 
complexing the chelant with a metal such as copper such as by mixing an 
aqueous solution of known concentration of the chelant with an aqueous 
solution containing copper (11) ions of known concentration and measuring 
chelation capacity by titrating the chelant with copper in the presence of 
an indicator dye. 
The succinic acid compounds are preferably employed in the form of 
water-soluble salts, notably alkali metal salts, ammonium salts, or alkyl 
ammonium salts. The alkali metal salts can involve one or a mixture of 
alkali metal salts although the potassium or sodium salts, especially the 
partial or complete sodium salts of the acids are preferred. 
Succinic acid mixtures are also useful, for instance, in food products 
vulnerable to metal-catalyzed spoilage or discoloration; in cleaning 
products for removing metal ions, that may reduce the effectiveness, 
appearance, stability, rinsibility, bleaching effectiveness, germicidal 
effectiveness or other property of the cleaning agents; in personal care 
products like creams, lotions, deodorants and ointments to avoid 
metal-catalyzed oxidation and rancidity, turbidity, reduced shelf-life and 
the like; in pulp and paper processing to enhance or maintain bleaching 
effectiveness; in pipes, vessels, heat exchangers, evaporators, filters 
and the like to avoid or remove scaling, in pharmaceuticals; in metal 
working; in textile preparation, desizing, scouring, bleaching, dyeing and 
the like; in agriculture as in chelated micronutrients or herbicides; in 
polymerization or stabilization of polymers; in the oil field such as for 
drilling, production, recovery, hydrogen sulfide abatement and the like. 
The chelants can be used in industrial processes whenever metal ions such 
as iron or copper are a nuisance and are to be prevented. 
The succinic acid mixtures are also useful in processes for the electroless 
deposition of metals such as nickel and copper. Electroless plating is the 
controlled autocatalytic deposition of a continuous film of metal without 
the assistance of an external supply of electrons such as described in 
U.S. Pat. Nos. 3,119,709 (Atkinson) and 3,257,215 (Schneble et al.). 
Non-metallic surfaces are pretreated by means within the skill in the art 
to make them receptive or autocatalytic for deposition. All or selected 
portions of a surface are suitably pretreated. Complexing agents are used 
to chelate a metal being deposited and prevent the metal from being 
precipitated from solution (i.e. as the hydroxide and the like). Chelating 
a metal renders the metal available to the reducing agent which converts 
the metal ions to metallic form. Growth of electroless plating can be 
attributed in part to growth of the electronics industry, especially for 
printed circuits. Electroless plating solutions are complex and contain a 
variety of ingredients. For example, an illustrative electroless copper 
solution would advantageously contain copper salts, a reducing agent, a 
material for the adjustment of the pH, a complexing agent, a buffer, and 
various additives to control stability, film properties, deposition rates, 
and the like. Typical copper salts include the water soluble salts such as 
copper sulfate, chloride, nitrate and acetate. Other organic and inorganic 
salts of copper may also be used. Typical of the reducing agents that can 
be used in alkaline electroless copper plating baths are formaldehyde and 
formaldehyde precursors such as glyoxal and paraformaldehyde. Borohydrides 
such as sodium or potassium borohydride and boranes such as amino boranes 
are also useful. In acidic copper solutions, hypophosphites such as sodium 
or potassium hypophosphite are used. On the acidic side, acids such as 
sulfuric may be employed. The pH adjustment is used to regulate the 
plating potential of the bath. Mixtures of the succinic acid compounds are 
preferably used to chelate the copper. A typical aqueous bath utilizing 
the succinic acid mixtures advantageously contains from about 0.002 to 
about 0.60 moles of a water soluble copper salt, the succinic acid 
mixtures at a molar ratio of approximately 1 to 2 times that required to 
complex the copper, an alkali metal hydroxide in sufficient amounts to 
give a pH of from about 10 to about 14, and e.g. formaldehyde from about 
0.03 to about 1.3 moles per liter. Used plating solutions, especially 
copper plating solutions, may be difficult to treat since they contain 
strong complexes such as EDTA (ethylenediaminetetraacetic acid) that are 
slowly biodegraded. The use of the more biodegradable chelant combinations 
described herein comprising a polyamino disuccinic acid and a polyamino 
monosuccinic acid and/or a monoamino monosuccinic acid, such as 
ethylenediamine N,N'-disuccinic acid in combination with ethylenediamine 
N-monosuccinic acid, are particularly useful in this regard. 
In the polymerization of rubber, mixtures of the succinic acid compounds 
are suitably used for preparing the redox catalysts used therein. They 
additionally prevent the precipitation of such compounds as iron hydroxide 
in an alkaline polymerization medium. 
In the textile industry, the chelants are suitably used for removing metal 
traces during the manufacture and dyeing of natural and synthetic fibers, 
thereby preventing many problems, such as dirt spots and stripes on the 
textile material, loss of luster, poor wettability, unlevelness and 
off-shade dyeings. 
Exemplary of various other uses of succinic acid mixtures are applications 
in pharmaceuticals, cosmetics and foodstuffs where metal catalyzed 
oxidation of olefinic double bonds and hence rancidification of goods is 
prevented. The chelates are also useful as catalysts for organic syntheses 
(for example air oxidation of paraffins, hydroformylation of olefins to 
alcohols). 
Metal chelates are important in agriculture because they supply 
micronutrients (trace metals such as iron, zinc, manganese, and copper) 
which are vital in the metabolism of both plants and animals. Plant 
problems previously ascribed to disease and drought are now recognized as 
possible symptoms of micronutrient deficiencies. Today these deficiencies 
are generally considered to be caused by (1) the trend toward higher 
analysis fertilizers containing fewer "impurities"; soils which had been 
adequately supplied with trace metals from these "impurities" have now 
become deficient; (2) intensified cropping practices which place a severe 
demand on the soil to supply micronutrients; to maintain high yields, 
supplementary addition of trace metals is now necessary; (3) high 
phosphorus fertilization, which tends to tie up metals in the soil in a 
form unavailable to the plant; and (4) the leveling of marginal land for 
cultivation, which often exposes subsoils deficient in micronutrients. The 
metal chelates of aminocarboxylates such as EDTA and HEDTA are commonly 
used to chelate micronutrients for agricultural use. The iron, copper, 
zinc, and manganese chelates of the succinic acid compound mixtures can be 
used to deliver these metals to the plant. Because of the excellent 
solubility, these metal chelates are more readily utilized by the plant 
than are the inorganic forms of the metals. This is especially true in 
highly competitive ionic systems. As a result, the micronutrients that are 
chelated to the succinic acid mixtures are more efficient than when 
compared to the inorganic sources. The chelates of iron, manganese, 
copper, and zinc with the biodegradable succinic acid mixtures comprising 
ethylenediamine N,N'-disuccinic acid and ethylenediamine N-monosuccinic 
acid are particularly preferred. Biodegradable chelants would have less 
residence time in soil. 
Further fields of application for the succinic acid mixtures include gas 
washing, conditioning or scrubbing (of e.g. flue, geothermal, sour, 
synthesis, process, fuel, or hydrocarbon gas) to remove at least one 
acidic gas, preferably the removal of NO.sub.x from flue gases, H.sub.2 S 
oxidation and metal extraction. Polyvalent metal chelates of the succinic 
acid mixtures are particularly useful in removing H.sub.2 S from a fluid, 
particularly a gas, containing H.sub.2 S, by (directly or indirectly) 
contacting the fluid with the chelates of a polyvalent metal in a higher 
valence state such that sulfur is formed along with the chelates of the 
metal in a lower valence state. The chelates of any oxidizing polyvalent 
metal capable of being reduced by reaction with H.sub.2 S or hydrosulfide 
and/or sulfide ions and, preferably which can be regenerated by oxidation, 
are suitable. Preferably the chelates are water soluble. Exemplary metals 
include lead, mercury, nickel, chromium, cobalt, tungsten, tin, vanadium, 
titanium, tantalum, platinum, palladium, zirconium, molybdenum, preferably 
iron, copper, or manganese, most preferably iron. 
Succinic acid mixtures are suitably used in any process of removal of 
H.sub.2 S within the skill in the art such as those exemplified by U.S. 
Pat. Nos. 4,421,733; 4,614,644; 4,629,608; 4,683,076; 4,696,802; 
4,774,071; 4,816,238; and 4,830,838, which are incorporated by reference 
herein. The polyvalent metal chelates are readily formed in aqueous 
solution by reaction of an appropriate salt, oxide or hydroxide of the 
polyvalent metal and the chelating agents in the acid form or an alkali 
metal or ammonium salt thereof. 
Preferably contact of H.sub.2 S, hydrosulfide, and/or sulfide with the 
chelates takes place at a pH of from about 6 to about 10. The more 
preferred range is from about 6.5 to about 9 and the most preferred range 
of pH is from about 7 to about 9. In general, operation at the highest 
portion of the range is preferred in order to operate at a high efficiency 
of hydrogen sulfide absorption. Since the hydrogen sulfide is an acid gas, 
there is a tendency for the hydrogen sulfide to lower the pH of the 
aqueous alkaline solution. Lower pH is preferable in the presence of 
carbon dioxide to reduce absorption thereof. Optimum pH also depends upon 
stability of a particular polyvalent metal chelate. At the pH values below 
about 6 the efficiency of hydrogen sulfide absorption is so low so as to 
be generally impractical. At pH values greater than 10, for instance with 
iron as the polyvalent metal, the precipitation of insoluble iron 
hydroxide may occur resulting in decomposition of the iron chelate. Those 
skilled in the art can ascertain a preferred pH for each operating 
situation. 
Buffering agents optionally useful as components of aqueous alkaline 
scrubbing solutions of the invention include those which are capable of 
maintaining the aqueous alkaline solution at a pH generally in a operating 
pH range of about 6 to about 10. The buffering agents are advantageously 
water soluble at the concentration in which they are effective. Examples 
of suitable buffering agents include the ammonium or alkali metal salts of 
carbonates, bicarbonates, or borates, including sodium carbonate, 
bicarbonate or sodium borate, particularly carbonates and bicarbonates 
when used in the presence of CO.sub.2 (carbon dioxide). 
The temperatures employed in a contacting or absorption-contact zone are 
not generally critical, except that the reaction is carried out below the 
melting point of sulfur. In many commercial applications, absorption at 
ambient temperatures is desired. In general, temperatures from about 
10.degree. C. to about 80.degree. C. are suitable, and temperatures from 
about 20.degree. C. to about 45.degree. C. are preferred. Contact times 
conveniently range from about 1 second to about 270 seconds or longer, 
with contact times of 2 seconds to 120 seconds being preferred. 
Suitable pressure conditions vary widely, depending on the pressure of the 
gas to be treated. For example, pressures in a contacting zone may vary 
from one atmosphere up to one hundred fifty or even two hundred 
atmospheres, with from one atmosphere to about one hundred atmospheres 
preferred. 
In H.sub.2 S removal, preferably at least an amount of chelate in a higher 
valence state stoichiometric with the H.sub.2 S to be removed is used. 
Preferred mole ratios of chelating agents to H.sub.2 S are from about 1:1 
to about 15:1, more preferably from about 2:1 to about 5:1. When chelates 
in both higher and lower valence states are present, it is generally 
preferable to maintain a concentration of the lower valence state chelates 
of at least about 5 times the concentration of that in the higher valence 
state. When, for instance iron chelates are used, they are preferably 
present in an amount from about 100 to about 100,000 ppm iron in the 
higher valence state most preferably from about 1000 to about 50,000 ppm 
by weight iron in the higher valence state. The circulation rate of the 
chelate solutions depends upon the hydrogen sulfide level in the H.sub.2 S 
containing fluid. In general, the circulation rate should be sufficient to 
provide from about 1 to about 6 moles and preferably about 2-4 moles of 
high valence (e.g. ferric) chelate products for every mole of H.sub.2 S 
entering the reaction zone. The contact time of the reactants should be at 
least about 0.05 second or more and preferably in the range from about 
0.02 to about 1.0 seconds. 
The succinic acid mixtures are preferably used in combination with 
additives such as rate enhancers (or catalysts, e.g. for conversion of 
H.sub.2 S to sulfur) and/or stabilizers for the chelates. Cationic 
polymeric catalysts are advantageous and include polyethyleneamines, 
poly(2-hydroxypropyl-1-N-methylammonium chloride) and the 1,1-dimethyl 
analog, polyN-(dimethylaminomethyl)acrylamide!, poly(2-vinylimidazolinum 
bisulfate), poly(diallyldimethyl ammonium chloride) and poly(N-dimethyl 
aminopropyl)-methacrylamide. These cationic polymers are well known and 
are commercially available under various trade names. See, for example, 
Commercial Organic Flocculants by J. Vostrcil et al Noyes Data Corp. 1972 
which is incorporated by reference herein. Other useful cationic catalysts 
are set forth in J. Macromol. Science-Chem. A4 pages 1327-1417 (1970) 
which is also incorporated by reference herein. Preferred catalysts 
include polyethylene amines and poly (diallyldimethyl ammonium chloride). 
Preferred concentration ranges for the polymeric catalysts are from about 
0.75 to about 5.0 weight percent, and from about 1.0 to about 3.0 weight 
percent is the most preferred range. The amount of polymeric catalyst is 
sufficient to provide a weight ratio of iron or other polyvalent metal in 
the range from 0.2 to 10:1. Concentrations of from about 10 to about 25 
ppm in solution are preferred. Stabilizing agents include, e.g. bisulfite 
ions such as sodium, potassium, lithium, ammonium bisulfite and mixtures 
thereof. They are used in stabilizing amounts, i.e. amounts sufficient to 
reduce or inhibit rate of degradation of the chelates, preferably from 
about 0.01 to about 0.6 equivalents per liter of solution, more preferably 
from about 0.05 to about 0.3 equivalents/liter. 
After the chelates of lower valence state are produced from that of higher 
valence state, they are preferably oxidized back to the higher valence 
state and recycled. Oxidation is suitably by any means within the skill in 
the art, e.g. electrochemically, but preferably by contact with an 
oxygen-containing gas, e.g. air. If CO.sub.2 is absorbed, it is preferably 
removed before contact with the oxygen-containing gas. The oxygen (in 
whatever form supplied) is advantageously supplied in a stoichiometric 
equivalent or excess with respect to the amount of lower valence state 
metal ion of the chelates present in the mixture. Preferably, the oxygen 
is supplied in an amount from about 1.2 to 3 fold excess and in a 
concentration of from about 1 percent to about 100 percent by volume, more 
preferably from about 5 percent to about 25 percent by volume. 
Temperatures and pressures are suitably varied widely, but generally those 
used in the contacting zone(s) are preferred, preferably temperatures of 
from about 10.degree. C. to about 80.degree. C. more preferable from about 
20.degree. C. to about 45.degree. C. with pressures from about 0.5 
atmosphere to about 3 or 4 atmospheres preferred. Mild oxidizing 
conditions are generally preferred to avoid degradation of the chelating 
agents. Such conditions are within the skill in the art. 
Sulfur produced by reaction of H.sub.2 S with the polyvalent metal chelates 
is optionally solubilized, e.g. by oxidation. Oxidation is suitably by any 
means within the skill in the art. When SO.sub.2 is present or easily 
generated by oxidation of H.sub.2 S (e.g. using oxygen or electrochemical 
means) it is a preferred oxidizing agent to produce, e.g. thiosulfates 
from the sulfur. Other suitable oxidizing agents include e.g. alkali metal 
or ammonium salts of inorganic oxidizing acids such as perchloric, 
chloric, hypochlorous, and permanganic acids. Otherwise, the sulfur is 
optionally recovered by means within the skill in the art including 
flocculation, settling, centrifugation, filtration, flotation and the 
like. 
Processes of the invention include, for instance: a process for removing at 
least a portion of H.sub.2 S from a fluid stream containing H.sub.2 S 
which comprises 
(A) contacting said fluid stream (optionally in a first reaction zone) with 
an aqueous solution at a pH range suitable for removing H.sub.2 S wherein 
said solution comprises higher valence polyvalent metal chelates of a 
polyamino disuccinic acid in combination with a polyamino monosuccinic 
acid and/or a monoamino monosuccinic acid whereby said higher valence 
polyvalent metal chelates are reduced to lower valence polyvalent metal 
chelates. Optionally the aqueous solution additionally comprises an 
oxidizing agent capable of oxidizing elemental sulfur to soluble sulfur 
compounds, and/or one or more water soluble cationic polymeric catalysts 
and/or a stabilizing amount of a stabilizing agent each as bisulfite ion. 
The process optionally includes at least one additional step such as: 
(B) contacting said solution containing the lower valence polyvalent 
chelated in a second reaction zone with an oxygen-containing gas stream 
whereby said chelates are reoxidized; 
(C) recirculating said reoxidized solution back to said first reaction 
zone; 
(D) feeding said aqueous solution from said oxidation zone to a sulfur 
recovery zone; 
(E) removing from said aqueous solution at least a portion of said sulfur 
and thereafter; 
(F) regenerating the aqueous admixture in a regeneration zone to produce a 
regenerated reactant; 
(G) returning aqueous admixture containing regenerated reactant from the 
regeneration zone to the contacting zone; 
(H) incinerating hydrogen sulfide to form sulfur dioxide; 
(I) selectively absorbing said sulfur dioxide in an alkaline aqueous 
solution without substantial carbon dioxide absorption to form a solution 
of sulfites essentially free of insoluble carbonates; 
(J) contacting said sulfur with said sulfites to form soluble sulfur 
compounds; 
(K) recirculating said reoxidized polyvalent metal chelates back to said 
fluid stream/aqueous chelates solution contacting step; and/or 
(L) condensing geothermal steam in a reaction zone, preferably in said 
first reaction zone, for contacting said reduced polyvalent metal 
chelates. 
Compositions of the invention, thus, include aqueous solutions of 
polyvalent metal chelates of the invention (in one or more oxidation 
states) with at least one of: H.sub.2 S, sulfide or bisulfide ions, rate 
enhancers such as poly(dimethyldiallyl ammonium chloride) and/or 
polyethyleneamines, and/or stabilizers such as bisulfite ions. 
Similarly, succinic acid mixtures are used in removal of nitrogen oxides, 
preferably nitric oxide (NO), from fluids containing them. For instance, 
nitrogen oxides (NO.sub.X) and SO.sub.2 can be removed from flue gas 
streams by absorbing the SO.sub.2 using an absorbent or reactant therefor, 
particularly an amine based absorbent such as a nitrogen-containing 
heterocyclic compound preferably having at least one carbonyl group such 
as a piperazinone; piperidinone, piperidine, piperazine or triazine having 
a carbonyl group; hydantoin; cyclic urea, oxazolidone or morpholinone in 
conjunction with a chelate of a polyvalent metal. Representative metal 
ions are chromium, cobalt, copper, iron, lead, manganese, mercury, 
molybdenum, nickel, palladium, platinum, tin, titanium, tungsten, and 
vanadium; preferably iron, copper, and/or nickel all preferably with a 
valence of +2, the more preferably iron, most preferably iron in the 
ferrous state. Such chelates are conveniently prepared by admixing a water 
soluble salt of the metal, such as a sulfate or acetate with a water 
soluble form of the chelating agents, e.g. a salt, advantageously in 
water. The chelates are useful in any process within the skill in the art 
such as those disclosed in U.S. Pat. Nos. 4,732,744 to Chang et al.; 
4,612,175 to Harkness et al.; 4,708,854 to Grinstead; 4,615,780 to Walker; 
4,126,529 to DeBerry; 4,820,391 to Walker; and 4,957,716 to Cichanowicz et 
al. When an SO.sub.2 absorbent is used, it is preferably regenerated, more 
preferably thermally regenerated, and preferably recycled. The 
concentration of NO.sub.X in the fluid (directly or indirectly) contacting 
the chelates is preferably from about 1 ppm to about 15,000 ppm by volume 
such as is found, for instance, in flue gases from burning e.g. coal. 
Whether used with an absorbent for SO.sub.2 or not, the metal chelates are 
advantageously present in the solution which contacts the NO.sub.X 
containing fluid at a metal ion concentration greater than about 100 ppm 
with a total chelating agent to metal ion molecular ratio of greater than 
or equal to one. The metal chelates are preferably present at a metal ion 
concentration of about 1,000 to about 10,000 ppm and a chelating agent to 
metal ion molecular ratio between about 1:1 and about 10:1. The optimum 
amounts depend on the chelating agents generally with preferred ratios 
between about 1:1 and to about 5:1. 
An absorber is suitably operated at a temperature of from about 0.degree. 
to about 120.degree. C., but is preferably operated at a temperature of 
from about 5.degree. to about 95.degree. C. In the process, both absorber 
and (optionally) a stripper are typically operated at a pressure of from 
about atmospheric to about 10 atmospheres (e.g. 0 to about 69 Pa gauge), 
however, atmospheric pressure is preferred for the convenience of lower 
equipment and operating costs and reduced SO.sub.2 absorbent losses. 
Higher temperatures and pressures are not deleterious so long as they are 
below the decomposition temperature of the chelates and absorbent, if 
present. The absorber is preferably maintained at a pH between about 3 and 
about 8 to retain NO.sub.x absorbence in the absorber. 
Chelates absorb NO.sub.x or act as stoichiometric reactants to increase the 
solubility of NO.sub.x in aqueous solution. Preferably sulfite and/or 
bisulfite ions collectively referred to herein as "sulfites" are also 
present. Such ions react with the NO.sub.X -chelate complex to form 
iminodisulfonate salts and free the chelate for NO.sub.x absorption. 
Examples of suitable soluble sulfite salts include sodium, potassium, 
lithium, magnesium and/or ammonium sulfite and/or bisulfite. When SO.sub.2 
is present, SO.sub.2 in aqueous solution forms sulfurous acid, and the 
concentration of sulfites in the absorbent is generally sufficient for 
iminodisulfonate formation without replenishment, but sulfites may be 
added, if necessary, to maintain a concentration of at least 0.05 to about 
1 g-moles/l absorbent, preferably at least about 0.1 g-moles/l. A sulfite 
salt is, thus, preferably present with the chelate. 
Alternatively, as described in U.S. Pat. No. 4,957,716, which is 
incorporated herein by reference in its entirety, the chelates promote 
absorption of NO.sub.X which may be converted to such compounds as 
HNO.sub.2 and HNO.sub.3 which react with HSO.sub.3, if present, to form 
hydroxylamine-disulfonate (HON(SO.sub.3 H).sub.2, abbreviated HADS) and 
related compounds, which are preferably subsequently converted to soluble 
ammonium and sulfate ions advantageously at a pH of about 4.2 or less, 
preferably about 4. More preferably the ammonium ions are subsequently 
removed, e.g. by absorption, and most preferably, the sulfate ions are 
precipitated. 
In removing NO.sub.X from a fluid, the polyvalent metal chelates are 
oxidized from a lower to a higher valence state. The lower valence metal 
chelates are preferably replenished, e.g. by replacement of the polyvalent 
metal ion of the chelates, but more preferably by reduction of the metal 
by any means within the skill in the art, such as by contact with a 
reducing agent, or preferably by electrochemical means (at a cathode). The 
chelate is, then, preferably recycled. 
When electrochemical regeneration is used, the solution containing the 
higher valence polyvalent metal chelates (which solution is preferably 
first (advantageously thermally) stripped of SO.sub.2) is preferably 
directed to a cathode compartment of an electrochemical cell comprised of 
an anode in an anode compartment separated, preferably by a membrane, from 
a cathode in a cathode compartment. An electrical potential is imposed 
across the anode and cathode to reduce inactive oxidized chelates to an 
active state. Preferably, an anionic exchange membrane is used. Heat 
stable amine salts may also be converted to free amine sorbent in the 
cathode compartment and soluble salt anions diffuse from the cathode 
compartment through the anion exchange membrane into the anode department. 
Preferably, in a further step, regenerated absorbent solution from the 
cathode compartment is recycled to the NO.sub.x containing fluid 
contacting step. The process more preferably additionally comprises a step 
of adjusting the pH of the regenerated recycle absorbent to from about 3 
to about 8. 
Compositions of the invention, thus, include aqueous solutions of the 
polyvalent metal polyamino disuccinic acids in combination with a 
polyamino monosuccinic acid with at least one of NO.sub.X, at least one 
(water soluble) sulfite, or at least one absorbent for SO.sub.2. Mixtures 
of the chelates in higher and lower valence states and mixtures of the 
chelate with the chelate-NO.sub.X complex are also aspects of the instant 
invention. 
Processes of the invention, thus, include a process for removing at least a 
portion of NO.sub.X, preferably NO, from a fluid containing NO.sub.X, said 
fluid preferably also containing SO.sub.2 and said fluid preferably being 
a gas, but suitably being a liquid, suspension, condensate and the like 
comprising the step of 
(A) (directly or indirectly) contacting the fluid with an aqueous solution 
comprising lower valence state polyvalent metal chelates of a polyamino 
disuccinic acid in combination with a polyamino monosuccinic acid and 
optionally additionally containing an absorbent for SO.sub.2 and/or a 
sulfite. 
The process optionally additionally comprises at least one of the following 
steps: 
(B) thermally stripping sulfur dioxide from an SO.sub.2 -rich absorbent 
solution to obtain an SO.sub.2 -lean absorbent solution; 
(C) directing the absorbent solution to a cathode compartment in an 
electrochemical cell, said cell having an anode in an anode compartment 
separated (preferably by a membrane) from a cathode in said cathode 
compartment, and imposing an electrical potential across said anode and 
said cathode to reduce oxidized chelates in said cathode compartment to 
obtain a regenerated absorbent solution; 
(D) recycling said regenerated absorbent solution to contacting step (A); 
(E) converting heat stable amine salts into free amine absorbent in said 
cathode compartment; 
(F) separating salt anions from said cathode compartment through said 
anionic exchange membrane into said anode compartment; 
(G) circulating an aqueous electrolyte solution through said anode 
compartment; 
(H) periodically refreshing said electrolyte to eliminate byproduct salts 
in said anode compartment; 
(I) adjusting said regenerated absorbent solution to a pH of from about 3 
to about 8 for a recycling step; 
(J) (when HADS is formed) mixing at least a portion of 
hydroxylaminedisulfonate in a reaction zone in an aqueous environment of 
pH of 4.2 or less, thereby converting said hydroxylaminedisulfonate to 
ammonium ions and sulfate ions in a second aqueous solution; 
(K) contacting said second aqueous solution with a second ammonium 
ion-absorbing sorbent suitable for removing ammonium ions from said second 
aqueous solution and separating said second sorbent from said second 
aqueous solution; 
(L) eluting said second sorbent and exposing the eluted ammonium ions or 
ammonia to nitrogen oxides at a temperature sufficient to form nitrogen 
and water therefrom; and/or 
(M) removing said sulfate ions from said second aqueous solution by forming 
a sulfate salt precipitate. 
Succinic acid mixtures are also useful in laundry detergents, particularly 
laundry detergents containing a detergent surfactant and builder. The 
mixtures of the succinic acids facilitate the removal of organic stains 
such as tea stains, grape juice stains and various food stains from 
fabrics during laundering operations. The stains are believed to contain 
metals such as copper and iron. The succinic acid mixtures are very 
effective in chelating these metals and thus aids in the removal of the 
troublesome stain. The compositions comprise from about 1% to about 80% by 
weight of a detergent surfactant, preferably from about 10% to about 50%, 
selected from nonionic surfactants, anionic surfactants, cationic 
surfactants, zwitterionic surfactants, ampholytic surfactants and 
mixturtes thereof; from about 5% to about 80% by weight of a detergent 
builder, preferably from about 10% to about 50%; and from about 0.1% to 
about 15% by weight of amino succinic acids, preferably from about 1% to 
about 10%, or alkali metal, alkaline earth, ammonium or substituted 
ammonium salt thereof, or mixtures thereof. 
When used in detergent applications, including dishwashing compositions, 
the molar ration of the polyamino disuccinic acid to the polyamino 
disuccinic acid to the polyamino monosuccinic acid is from about 99:1 to 
about 5:95. 
Nonionic surfactants that are suitable for use in the present invention 
include those that are disclosed in U.S. Pat. No. 3,929,678 (Laughlin et 
al.), incorporated herein by reference. Included are the condensation 
products of ethylene oxide with aliphatic alcohols, the condensation of 
ethylene oxide with the base formed by the condensation of propylene oxide 
and propylene glycol or the product formed by the condensation of 
propylene oxide and ethylendiamine. Also included are the various 
polyethylene oxide condensates of alkyl phenols and various amine oxide 
surfactants. 
Anionic surfactants that are suitable for use are described in U.S. Pat. 
No. 3,929,678. These include sodium and potassium alkyl sulfates; various 
salts of higher fatty acids, and alkyl polyethoxylate sulfates. 
Cationic surfactants that may be used are described in U.S. Pat. No. 
4,228,044 (Cambre), incorporated herein by reference. Especially preferred 
cationic surfactants are the quaternary ammonium surfactants. 
In addition, ampholytic and zwitterionic surfactants such as those taught 
in U.S. Pat. No. 3,929,678 can be used in the present invention. 
Suitable builder substances are for example: wash alkalis, such as sodium 
carbonate and sodium silicate, or complexing agents, such as phosphates, 
or ion exchangers, such as zeolites, and mixtures thereof. These builder 
substances have as their function to eliminate the hardness ions, which 
come partially from the water, partially from dirt or textile material, 
and to support the surfactant action. In addition to the above mentioned 
builder substances, the builder component may further contain cobuilders. 
In modern detergents, it is the function of cobuilders to undertake some 
of the functions of phosphates, e.g. sequestration, soil antiredeposition 
and primary and secondary washing action. 
The builder components may contain for example water-insoluble silicates, 
as described for example in German Laid-Open Application DE-OS No. 
2,412,837, and/or phosphates. As phosphate it is possible to use 
pyrophosphates, triphosphates, higher polyphosphates and metaphosphates. 
Similarly, phosphorus-containing organic complexing agents such as 
alkanepolyphosphonic acids, amino- and hydroxy-alkanepolyphosphonic acids 
and phosphonocarboxylic acids, are suitable for use as further detergent 
ingredients generally referred to as stabilizers or phosphonates. Examples 
of such detergent additives are the following compounds: 
methanediphosphonic acid, propane-1,2,3-triphosphonic acid, 
butane-1,2,3,4-tetraphosphonic acid, polyvinylphosphonic acid, 
1-aminoethane,-1,1-diphosphonic acid, aminotrismethylenetriphosphonic 
acid, methylamino- or ethylamino-bismethylenediphosphonic acid, 
ethylenediaminetetramethylenephosphonic acid, 
diethylenetriaminopentamethylenephosphonic acid, 
1-hydroxyethane-1,1-diphosphonic acid, phosphonoacetic and 
phosphonopropionic acid, copolymers of vinylphosphonic acid and acrylic 
and/or maleic acid and also partially or completely neutralized salts 
thereof. 
Further organic compounds which act as chelants for calcium that may be 
present in detergent formulations are polycarboxylic acids, 
hydroxycarboxylic acids and aminocarboxylic acids which are usually used 
in the form of their water-soluble salts. 
Examples of polycarboxylic acids are dicarboxylic acids of the general 
formula HOOC--(CH.sub.2).sub.m -COOH where m is 0-8, and maleic acid, 
methylenemalonic acid, citraconic acid, mesaconic acid, itaconic acid, 
noncyclic polycarboxylic acids having 3 or more carboxyl groups in the 
molecule, e.g. tricarballylic acid, aconitic acid, ethylenetetracarboxylic 
acid, 1,1,3-propanetricarboxylic acid, 1,1,3,3,5,5-pentanehexacarboxylic 
acid, hexanehexacarboxylic acid, cyclic di- or poly-carboxylic acids ( 
e.g. cyclopentanetetracarboxylic acid, cyclohexanehexacarboxylic acid, 
tetrahydrofurantetracarboxylic acid, phthalic acid, terephthalic acid, 
benzene-tricarboxylic, -tetra-carboxylic or -pentacarboxylic acid) and 
mellitic acid. 
Examples of hydroxymonocarboxylic and hydroxypolycarboxylic acids are 
glycollic acid, lactic acid, malic acid, tartronic acid, methyltartronic 
acid, gluconic acid, glyceric acid, citric acid, tartaric acid and 
salicylic acid. 
Examples of aminocarboxylic acids are glycine, glycylglycine, alanine, 
asparagine, glutamic acid, aminobenzoic acid, iminodiacetic acid, 
iminotriacetic acid, hydroxyethyliminodiacetic acid, 
ethylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic 
acid, diethylenetriaminepentaacetic acid and higher homologues which are 
prepared by polymerization of an N-aziridylcarboxylic acid derivative, for 
example of acetic acid, succinic acid or tricarballylic acid, and 
subsequent hydrolysis, or by condensation of polyamines having a molecular 
weight of from 500 to 10,000 with salts of chloroacetic or bromoacetic 
acid. 
Preferred cobuilder substances are polymeric carboxylates. These polymeric 
carboxylic acids include the carboxymethyl ethers of sugars, of starch and 
of cellulose. Zeolites and phosphates are also useful. 
Particularly important polymeric carboxylic acids are for example the 
polymers of acrylic acid, maleic acid, itaconic acid, mesaconic acid, 
aconitic acid, methylenemalonic acid, citraconic acid and the like, the 
copolymers between the aforementioned carboxylic acids, for example a 
copolymer of acrylic acid and maleic acid in a ration of 70:30 and having 
a molecular weight of 70,000, or copolymers thereof with ethylenically 
unsaturated compounds, such as ethylene, propylene, isobutylene, vinyl 
methyl ether, furan, acrolein, vinyl acetate, acrylamide, acrylonitrile 
methacrylic acid, crotonic acid and the like, e.g. the 1:1 copolymers of 
maleic anhydride and methyl vinyl ether having a molecular weight of 
70,000 or the copolymers of maleic anhydride and ethylene and/or propylene 
and/or furan. 
The cobuilders may further contain soil antiredeposition agents which keep 
the dirt detached from the fiber in suspension in the liquid and thus 
inhibit graying. Suitable for this purpose are water-soluble colloids 
usually of an organic nature for example the water-soluble salts of 
polymeric carboxylic acids, glue, gelatin, salts of ethercarboxylic acids 
or ethersulfonic acids of starch and of cellulose or salts of acid 
sulfates of cellulose and of starch. Even water-soluble polyamides 
containing acid groups are suitable for this purpose. It is also possible 
to use soluble starch products and starch products other than those 
mentioned above, for example degraded starch, aldehyde starches and the 
like. Polyvinylpyrrolidone is also usable. 
Bleaching agents that can be used are in particular hydrogen peroxide and 
derivatives thereof or available chlorine compounds. Of the bleaching 
agent compounds which provide H.sub.2 O.sub.2 in water, sodium perborate 
hydrates, such as NaBO.sub.2.H.sub.2 O.sub.2.3H.sub.2 O and 
NaBO.sub.2.H.sub.2 O.sub.2 and percarbonates such as 2 Na.sub.2 CO.sub.3.3 
H.sub.2 O.sub.2, are of particular importance. These compounds can be 
replaced in part or in full by other sources of active oxygen, in 
particular by peroxyhydrates, such as peroxyphosphonates, citrate 
perhydrates, urea, H.sub.2 O.sub.2 -providing peracid salts, for example 
caroates, perbenzoates or peroxyphthalates or other peroxy compounds. 
Aside from those according to the invention, customary water-soluble and/or 
water-insoluble stabilizers for peroxy compounds can be incorporated 
together with the former in amounts from 0.25 to 10 percent by weight, 
based on the peroxy compound. Suitable water-insoluble stabilizers are the 
magnesium silicates MgO:SiO.sub.2 from 4:1 to 1:4, preferably from 2:1 to 
1:2, in particular 1:1, in composition, usually obtained by precipitation 
from aqueous solutions. Other alkaline earth metals of corresponding 
composition are also suitably used. 
To obtain a satisfactory bleaching action even in washing at below 
80.degree. C., in particular in the range from 60.degree. C. to 40.degree. 
C., it is advantageous to incorporate bleach activators in the detergent, 
advantageously in an amount from 5 to 30 percent by weight, based on the 
H.sub.2 O.sub.2 -providing compound. 
Activators for peroxy compounds which provide H.sub.2 O.sub.2 in water are 
certain N-acyl and O-acyl compounds, in particular acetyl, propionyl or 
benzyl compounds, which form organic peracids with H.sub.2 O.sub.2 and 
also carbonic and pyrocarbonic esters. Useful compounds are inter alia: 
N-diacylated and N,N'-tetraacylated amines, e.g. 
N,N,N',N'-tetraacetyl-methylenediamine or -ethylenediamine, 
N,N-diacetylaniline and N,N-diacetyl-p-toluidine, and 1,3-diacylated 
hydantoins, alkyl-N-sulfonyl-carboxamides, N-acylated hydrazides, acylated 
triazoles or urazoles, e.g. monoacetylmaleohydrazide, O,N,N-trisubstituted 
hydroxylamines, e.g. O-benzoyl-N,N-succinylhydroxylamine, 
O-acetyl-N,N-succinyl-hydroxylamine, 
O-p-methoxybenzoyl-N,N-succinyl-hydroxylamine, 
O-p-nitrobenzoyl-N,N-succinylhydroxylamine and 
O,N,N-triacetylhydroxylamine, carboxylic anhydrides, e.g. benzoic 
anhydride, m-chlorobenzoic anhydride, phthalic anhydride and 
4-chlorophthalic anhydride, sugar esters, e.g. glucose pentaacetate, 
imidazolidine derivatives, such as 
1,3-diformyl-4,5-diacetoxyimidazolidine, 1,3-diacetyl-4,5-diacetoxyimidazo 
line and 1,3-diacetyl-4,5-dipropionyloxyimidazolidine, acylated 
glycolurils, e.g. tetrapropionylglycoluril or diacetyldibenzoylglycoluril, 
dialkylated 2,5-diketopiperazines, e.g. 
1,4-dipropionyl-2,5-diketopiperazine and 
1,4-dipropionyl-3,6-dimethyl-2,5-diketopiperazine and 
1,4-dipropionyl-3,6-2,5-diketopiperazine, acetylation and benzoylation 
products of propylenediurea or 2,2-dimethylpropylenediurea. 
The bleaching agents used can also be active chlorine compounds of the 
inorganic or organic type. Inorganic active chlorine compounds include 
alkali metal hypochlorites which can be used in particular in the form of 
their mixed salts and adducts on orthophosphates or condensed phosphates, 
for example on pyrophosphates and polyphosphates or on alkali metal 
silicates. If the detergent contains monopersulfates and chlorides, active 
chlorine will form in aqueous solution. 
Organic active chlorine compounds are in particular the N-chlorine 
compounds where one or two chlorine atoms are bonded to a nitrogen atom 
and where preferably the third valence of the nitrogen atom leads to a 
negative group, in particular to a CO or SO.sub.2 group. These compounds 
include dichlorocyanuric and trichlorocyanuric acid and their salts, 
chlorinated alkylguanides or alkylbiguanides, chlorinated hydantoins and 
chlorinated melamines. 
Examples of additional assistants are: suitable foam regulants, in 
particular if surfactants of the sulfonate or sulfate type are used, are 
surface-active carboxybetaines or sulfobetaines and also the above 
mentioned nonionics of the alkylolamide type. Also suitable for this 
purpose are fatty alcohols or higher terminal diols. 
Reduced foaming, which is desirable in particular for machine washing, is 
frequently obtained by combining various types of surfactants, for example 
sulfates and/or sulfonates, with nonionics and/or with soaps. In the case 
of soaps, the foam inhibition increases with the degree of saturation and 
the number of carbon atoms of the fatty acid ester; soaps of saturated 
C.sub.20 -C.sub.24 -fatty acids, therefore, are particularly suitable for 
use as foam inhibitors. 
The nonsurfactant-like foam inhibitors include optionally 
chlorine-containing N-alkylated aminotriazines which are obtained by 
reacting 1 mole of cyanuric chloride with from 2 to 3 moles of a mono- 
and/or dialkylamine having 6 to 20, preferably 8 to 18, carbon atoms in 
the alkyl. A similar effect is possessed by propoxylated and/or 
butoxylated aminotriazines, for example, products obtained by addition of 
from 5 to 10 moles of propylene oxide onto 1 mole of melamine and further 
addition of from 10 to 50 moles of butylene oxide onto this propylene 
oxide derivative. 
Other suitable nonsurfactant-like foam inhibitors are water-soluble organic 
compounds, such as paraffins or haloparaffins having melting points below 
100.degree. C., aliphatic C.sub.18 - to C.sub.40 -ketone and also 
aliphatic carboxylic esters which, in the acid or in the alcohol moiety, 
possibly even both these moieties, contain not less than 18 carbon atoms 
(for example triglycerides or fatty acid fatty alcohol esters); they can 
be used in particular in combinations of surfactants of the sulfate and/or 
sulfonate type with soaps for foam inhibition. 
The detergents may contain optical brighteners for cotton, for polyamide, 
for polyacrylonitrile or for polyester fabrics. Examples of suitable 
optical brighteners are derivatives of diaminostilbenedisulfonic acid for 
cotton, derivatives of 1,3-diarylpyrazolines for polyamide, quaternary 
salts of 7-methoxy-2-benzimidazol-2'-ylbenzofuran or of derivatives form 
the class of the 
7-1',2',5'-triazol-1'-yl!-3-1",2",4"-triazol-1"-y!coumarins for 
polyacrylonitrile. Examples of brighteners suitable for polyester are 
products of the class of the substituted styryls, ethylenes, thiophenes, 
naphthalenedicarboxylic acids or derivatives thereof, stilbenes, coumarins 
and naphthalimides. 
It is preferred that laundry compositions herein also contain enzymes to 
enhance their through-the-wash cleaning performance on a variety of soils 
and stains. Amylase and protease enzymes suitable for use in detergents 
are well known in the art and in commercially available liquid and 
granular detergents. Commercial detersive enzymes (preferably a mixture of 
amylase and protease) are typically used at levels of from about 0.001 to 
about 2 weight percent, and higher, in the present cleaning compositions. 
Detergent formulations of this invention may contain minor amounts of other 
commonly used materials in order to enhance the effectiveness or 
attractiveness of the product. Exemplary of such materials are soluble 
sodium carboxymethyl cellulose or other soil redeposition inhibitors; 
benzotriazole, ethylene thiourea, or other tarnish inhibitors; perfume; 
fluorescers; dyes or pigments; brightening agents; enzymes; water; 
alcohols; other builder additives, such as the water soluble salts of 
ethylenediaminetetraacetic acid, 
N-(2-hydroxyethyl)-ethylenediaminetriacetic acid; and pH adjusters, such 
as sodium hydroxide and potassium hydroxide. Other optional ingredients 
include pH regulants, polyester soil release agents, hydrotropes and 
gel-control agents, freeze-thaw stabilizers, bactericides, preservatives, 
suds control agents, fabric softeners especially clays and mixtures of 
clays with various amines and quaternary ammonium compounds and the like. 
In the built liquid detergent formulations of this invention, the use of 
hydrotropic agents may be found efficacious. Suitable hydrotropes include 
the water-soluble alkali metal salts of toluene sulfonic acid, benzene 
sulfonic acid, and xylene sulfonic acid. Potassium toluene sulfonate and 
sodium toluene sulfonate are preferred for this use and will normally be 
employed in concentrates ranging up to about 10 or 12 percent by weight 
based on the total composition. 
It will be apparent from the foregoing that the compositions of this 
invention may be formulated according to any of the various commercially 
desirable forms. For example, the formulations of this invention may be 
provided in granular form, in liquid form, in tablet form of flakes or 
powders. 
Use of these ingredients is within the skill in the art. Compositions are 
prepared using techniques within the skill in the art. 
The invention will be further clarified by a consideration of the following 
examples, which are intended to be purely exemplary of the present 
invention.

EXAMPLE 1 
An approximate 0.01M iron (ferric) chelate solution of ethylenediamine 
N,N'-disuccinic acid (EDDS) was prepared by adding 1.46 grams of EDDS 
(0.0050 moles) and 200 grams of deionized water to a beaker. The mixture 
was stirred with a magnetic stirrer bar and the pH was adjusted to 
approximately 8.7 by the addition of an aqueous ammonia solution. 
Approximately 2.3 grams of an iron nitrate solution (11.7% iron) from 
Shepherd Chemical Company was added with stirring. The iron chelate 
solution (pH=3.1 ) was diluted in a volumetric flask to a final volume of 
500 milliliters with deionized water. Fifty gram aliquots of the above 
solution were then placed in 2 oz. bottles and the pH adjusted to 5.0, 
6.0, 7.0, 8.0, 9.0 and 10.0 by the addition of a few drops of an aqueous 
ammonia solution. The samples were allowed to stand for 7 days at which 
time the pH 10 sample had iron hydroxide present. "Overheads" from each of 
the samples were filtered and analyzed for soluble iron by inductively 
coupled plasma spectroscopy. The results are given in Table 1. 
TABLE 1 
______________________________________ 
pH ppm Fe 
______________________________________ 
5 514 
6 530 
7 531 
8 533 
9 514 
10 181 
______________________________________ 
EXAMPLE 2 
An approximate 0.01M iron chelate solution of ethylenediamine 
N-monosuccinic acid (EDMS) was prepared by adding 0.88 grams of EDMS 
(0.0050 moles) and 200 grams of deionized water to a beaker. The mixture 
was stirred with a magnetic stirrer bar and approximately 2.3 grams of 
iron nitrate solution (11.7% iron) was added with stirring. The iron 
chelate solution (pH=2.3) was diluted in a volumetric flask to a final 
volume of 500 milliliters with deionized water. Fifty gram aliquots of the 
solution were placed in 2 oz. bottles and the pH adjusted to 5.0, 6.0, 
7.0, 8.0, 9.0 and 10.0 by the addition of a few drops of an aqueous 
ammonia solution. The samples were allowed to stand for 7 days at which 
time the pH 9 and 10 samples had iron hydroxide present. "Overheads" from 
each of the samples were filtered and analyzed for soluble iron by 
inductively coupled plasma spectroscopy. The results are given in Table 2. 
TABLE 2 
______________________________________ 
pH ppm Fe 
______________________________________ 
5 499 
6 501 
7 498 
8 507 
9 6 
10 1 
______________________________________ 
EXAMPLE 3 
In a similar manner to Examples I and 2 above, 0.01 molar iron chelate 
solutions were prepared from various mixtures of EDDS and EDMS. The total 
amount of chelating agent was held constant at 0.0050 moles. Ratios 
(molar) of EDDS to EDMS of 90/10, 80/20, 60/40, 40/60, 20/80 and 10/90 
were prepared and 50 gram aliquots were adjusted as described earlier. The 
samples were allowed to stand for 7 days at which time the pH 10 samples 
at all ratios had iron hydroxide present. In addition, the pH sample at a 
molar ratio of 10:90 had iron hydroxide present. "Overheads" from each of 
the samples were filtered and analyzed for soluble iron. The results 
obtained for the pH 9 samples at each of the ratios is summarized in Table 
3. The "expected" value for iron for each ratio is also given as well as 
the results for EDDS and EDMS. A comparison of the expected ppm iron with 
the actual values measured demonstrates the synergistic effect obtained 
from the EDDS/EDMS mixtures. After an additional 17 days, the pH 9 samples 
at mole ratios of 20:80 and 40:60 had iron hydroxide present. A small 
amount of iron hydroxide was noted for the 60:40 ratio. 
TABLE 3 
______________________________________ 
EDDS/EDMS ppm Fe ppm Fe 
Molar Ratio Expected Found 
______________________________________ 
100/0 -- 514 
90/10 463 519 
80/20 412 508 
60/40 311 508 
40/60 209 499 
20/80 108 526 
10/90 57 215 
0/100 -- 6 
______________________________________ 
EXAMPLE 4 
Samples of EDMS and various isomers of EDDS were tested for 
biodegradability according to the OECD 301B Modified Sturm Test. The test 
measures the CO.sub.2 produced by the test compound or standard, which is 
used as the sole carbon source for the microbes. The following samples 
were tested: 
a) EDMS racemic mixture 
b) R,R-EDDS 
c) S,S-EDDS 
d) EDDS racemic mixture, approx. 25% each R,R-EDDS and S,S-EDDS, and 50% 
meso-EDDS 
e) Sample A: contains 69.8% EDDS racemic mixture, 16.7% EDMS racemic 
mixture, and 13.5% fumaric acid 
Each compound was tested at a 20 ppm dose level (based on EDMS or EDDS 
component active as the acid form). Each compound is evaluated as a series 
comprising a test vessel, a standard vessel, and a blank vessel. The seed 
innoculum for each test compound series was obtained from organisms 
previously exposed to the respective compound in a semi-continuous 
activated sludge test. The total volume in the vessels was 2100 ml each. 
To confirm the viability of each seed innoculum, acetic acid was used as 
the standard at a concentration of 20 ppm in each series. A blank vessel 
is used to determine the inherent CO.sub.2 evolved from each respective 
innoculum. Carbon dioxide captured in respective barium hydroxide traps 
was measured at various times during the 28-day test period. The 
cumulative results of the test are summarized in Table 4. 
TABLE 4 
______________________________________ 
Sturm Test Results of EDMS and EDDS Samples 
Theoretical Measured % Theoretical 
Test Compound 
mMoles CO.sub.2 
mMoles CO.sub.2 
CO.sub.2 Produced 
______________________________________ 
EDMS 1.43 1.08 75% 
R,R-EDDS 1.44 0.21 14% 
S,S-EDDS 1.44 1.03 72% 
EDDS rac. mix 
1.44 0.43 30% 
Sample A 2.05 1.40 68% 
Acetate Standards 
1.40 1.19 .+-. 0.12 
85% 
(ave.) (ave.) 
______________________________________ 
Sample A was added to the test cell to achieve a 20 ppm level of the active 
EDDS in the sample. Therefore, the theoretical total of CO.sub.2 possible 
is 1.44 mMoles CO.sub.2 from 20 ppm EDDS isomers, plus the theoretical 
amount of CO.sub.2 from EDMS (0.34 mMoles) and the theoretical amount of 
CO.sub.2 from fumaric acid (0.27 mMoles). The total theoretical amount of 
CO.sub.2 possible from this sample is thus 1.44 EDDS+0.34 EDMS+0.27 
fumaric=2.05 mMoles CO.sub.2. 
Using the experimental data in Table 4, the amount of CO.sub.2 that would 
be expected to actually be produced by Sample A can be calculated: 
As shown in Table 4, the EDMS produced 75% of the theoretical CO.sub.2. The 
theoretical amount of CO.sub.2 possible from the EDMS present in Sample A 
is 0.34 mMoles. Thus, multiplying the theoretical amount of CO.sub.2 that 
could be produced by the EDMS in Sample A by 75% yields an expected amount 
of 0.34.times.0.75=0.26 mMoles. 
Since fumaric acid was not determined separately, it is assumed that 95% of 
theoretical CO.sub.2 is produced (this assumes greater CO.sub.2 production 
than the acetate standard, which is highly unlikely) as a conservative 
estimate. The theoretical amount of CO.sub.2 possible from the fumaric 
acid present in Sample A is 0.27 mMoles. Thus, multiplying the theoretical 
amount of CO.sub.2 that could be produced by the fumaric acid in Sample A 
by 95% yields an expected amount of 0.27.times.0.95=0.26 mMoles. 
From Table 4, the EDDS racemic mixture produced 30% of theoretical 
CO.sub.2. The theoretical amount of CO.sub.2 from the EDDS in Sample A is 
1.44 mMoles. Therefore, the expected amount of CO.sub.2 produced from the 
EDDS portion of Sample A is 1.44.times.0.3=0.43 mMoles, as given in Table 
4. 
Adding the amounts of CO.sub.2 expected from the EDMS, fumaric and EDDS in 
Sample A, the total amount is 0.26 mMoles CO.sub.2 from EDMS+0.26 mMoles 
CO.sub.2 from fumaric+0.43 mMoles CO.sub.2 from EDDS isomers=0.95 mMoles 
CO.sub.2. Dividing the expected amount (0.95 mMoles CO.sub.2) by the 
theoretical amount (2.05 mMoles CO.sub.2) gives an expected % theoretical 
CO.sub.2 produced of 46%. The amount observed is a total of 68% of 
theoretical. These results are further summarized in Table 5. 
TABLE 5 
______________________________________ 
Expected vs Observed CO.sub.2 Production in Sample A 
Compound in 
Theoretical Expected % Theor CO.sub.2 
Sample A mMoles CO.sub.2 
mMoles CO.sub.2 
Expected 
______________________________________ 
EDMS 0.34 0.26 75% 
fumaric acid 
0.27 0.26 95% 
EDDS rac. mix 
1.44 0.43 30% 
Predicted Total 
2.05 0.95 46% 
Observed Total 
2.05 1.40 68% 
______________________________________ 
Another way to evaluate the data is to calculate the amount of CO.sub.2 
that would be expected from only the EDDS portion of Sample A. 
From Table 5, the expected amount of CO.sub.2 from the EDDS in Sample A is 
0.43 mMoles, based on experimental measurements of the EDDS racemic 
mixture. 
The expected amount of CO.sub.2 from the EDMS portion of the sample is 0.26 
mMoles and the expected amount of CO.sub.2 from the fumaric acid portion 
is 0.26 mMoles. If the amounts of expected CO.sub.2 from EDMS and fumaric 
acid are subtracted from the observed amount of CO.sub.2 produced, we are 
left with the amount of CO.sub.2 produced by the EDDS portion of the 
sample=1.40 mMoles (total CO.sub.2 produced by Sample A)-0.26 mMoles 
(predicted amount of CO.sub.2 produced from EDMS in Sample A)-0.26 mMoles 
(predicted amount of CO.sub.2 produced from fumaric in Sample A)=0.88 
mMoles CO.sub.2 produced by the EDDS portion of Sample A. 
The theoretical amount of CO.sub.2 possible from the EDDS portion of Sample 
A is 1.44 mMoles CO.sub.2. Therefore, the predicted (and experimentally 
measured) % theoretical CO.sub.2 produced is 0.43 mMoles divided by 1.44 
mMoles=30%. However, in these tests, the observed % theoretical CO.sub.2 
produced calculated for the EDDS portion of Sample A is 0.88 mMoles. 
Dividing 0.88 mMoles by the theoretical 1.44 mMoles=61% theoretical 
CO.sub.2 produced by the EDDS portion of Sample A. A value of greater than 
60% of the theoretical amount of CO.sub.2 produced in this test indicates 
that a compound is readily biodegradable. The experimentally measured 
value for the EDDS portion of Sample A is 30%. 
The data for the EDDS portion of Sample A indicates that from a 
biodegradability standpoint, it appears to be an advantage to have a 
mixture of EDDS and EDMS vs EDDS alone. Table 6 summarizes the above 
calculations. 
TABLE 6 
______________________________________ 
Expected vs Observed CO.sub.2 Produced from EDDS in Sample A 
% of 
Theoretical 
mMoles CO.sub.2 
CO.sub.2 
______________________________________ 
Predicted amount CO.sub.2 
0.43 30% 
expected from EDDS portion of 
Sample A 
"Observed" amount of CO.sub.2 
0.88 61% 
produced from EDDS portion of 
(from EDDS 
Sample A only) 
______________________________________ 
EXAMPLE 5 
Ratios (molar) of EDDS to EDMS of 90/10, 80/20, 60/40, 40/60, 20/80 and 
10/90 were prepared and titrated with 0.01M copper solution using Murexide 
as the indicator. The chelant mixtures were all found to complex copper on 
an equivalent (equimolar) basis. 
Other embodiments of the invention will be apparent to those skilled in the 
art from a consideration of this specification or practice of the 
invention disclosed herein. It is intended that the specification and 
examples be considered as exemplary only, with the true scope and spirit 
of the invention being indicated by the following claims.