WO2023186679A1

WO2023186679A1 - Process for making aqueous solutions containing a complexing agent in high concentration

Info

Publication number: WO2023186679A1
Application number: PCT/EP2023/057426
Authority: WO
Inventors: Matthias Arndt; Astrid Schmidt; Matthias Voges; Michael Klemens Mueller
Original assignee: Basf Se
Priority date: 2022-03-30
Filing date: 2023-03-23
Publication date: 2023-10-05

Abstract

The present invention is directed towards a process for making an aqueous solution, preferably with a total dry content of at least 45%, comprising in the range of from 30 to 75 % by weight of an aminocarboxylate complexing agent, preferably selected from the alkali metal salts of aminocarboxylate complexing agents, and in the range of from 0.1 to 40 % by weight of organic acid and/or inorganic acid, preferably organic acid, in acidic form, partially deprotonated form, or fully deprotonated form, percentages referring to the total respective aqueous solution, comprising the step of combining an aqueous solution of complexing agent (A) with an inorganic and/or organic acid (B).

Description

Process for making aqueous solutions containing a complexing agent in high concentration

Description

The present invention is directed towards a process for making an aqueous solution, preferably with a total dry content of at least 45%, comprising

(A) in the range of from 30 to 75 % by weight, preferably 40 to 70 % by weight, of an aminocarboxylate complexing agent, preferably selected from the alkali metal salts of aminocarboxylate complexing agents, more preferably selected from alkali metal salts of methylglycine diacetic acid, and

(B) in the range of from 0.1 to 40 % by weight of organic acid and/or inorganic acid, preferably organic acid, in acidic form, partially deprotonated form, or fully deprotonated form, percentages referring to the total respective aqueous solution, comprising the step of combining an aqueous solution of complexing agent (A) with an inorganic and/or organic acid (B).

Complexing agents such as methyl glycine diacetic acid (MGDA) and glutamic acid diacetic acid (GLDA) and their respective alkali metal salts are useful sequestrants for alkaline earth metal ions such as Ca²⁺ and Mg²⁺. For that reason, they are recommended and used for various purposes such as laundry detergents and for automatic dishwashing (ADW) formulations, in particular for so-called phosphate-free laundry detergents and phosphate-free ADW formulations. For shipping such complexing agents, in most cases either solids such as granules are being applied or aqueous solutions.

Many industrial users wish to obtain complexing agents in aqueous solutions that are as highly concentrated as possible. The lower the concentration of the requested complexing agent the more water is being shipped. Said water adds to the costs of transportation, and it has to be removed later. Although about 40% by weight solutions of MGDA and even 45% by weight solutions of GLDA can be made and stored at room temperature, local or temporarily colder solutions may lead to precipitation of the respective complexing agent, as well as nucleating by impurities. Said precipitations may lead to incrustations in pipes and containers, and/or to impurities or inhomogeneity during formulation.

There are a few publications disclosing the use of inorganic or organic acids together with complexing agents. However, these publications mostly aim at reducing malodor in solids (e. g. granules) containing complexing agents, e. g as in US 10,377,969 B2. Another known use of inorganic acids is their use as shell in a core-shell (solid) particle containing a complexing agent (EP 2584028 B1). The use of inorganic or organic acids for increasing the active content of complexing agents in aqueous solutions has not been described so far. Granules and powders are useful because the amount of water shipped can be neglected but for most mixing and formulation processes an extra dissolution step is required. Additives that may enhance the solubility of the respective complexing agents may be consid- ered but such additives should not negatively affect the properties of the respective complexing agent. It was therefore the objective of the present invention to provide highly concentrated aqueous solutions of complexing agents such as MGDA or GLDA (particularly MGDA) that are stable at temperatures in the range from zero to 50°C. It was further an objective of the present invention to provide a method for manufacturing of highly concentrated aqueous solutions of complexing agents such as MGDA or GLDA (particularly MGDA) that are stable at temperatures in the range from zero to 50°C. Neither such method nor such aqueous solution should require the use of additives that negatively affect the properties of the respective complexing agent. Accordingly, the process for making an aqueous solution defined at the outset has been found, hereinafter also being referred to as process according to the invention. The dry content may be determined by drying the respective solution for 60min at 200°C on a drying balance. In one embodiment, the inventive aqueous solution has a pH value in the range of from 1 to 13, more preferred 4 to 11, particularly 5 to 11, more particularly 7 to 11. According to an embodiment of the inventive process, the organic acid may be chosen from any di- or tricarboxylic acid or any polycarboxylic acid, preferably citric acid. Examples of dicarbox- ylic acids are tartaric acid, adipic acid, glutamic acid, maleic acid, fumaric acid, and malic acid. Polycarboxylic acids may be aromatic or aliphatic. In an especially preferred embodiment of the inventive process, an organic acid is used and the organic acid is citric acid. According to another embodiment of the inventive process, the inorganic acid is chosen from any inorganic acid, preferably H2SO4, HCl or CO2. In one embodiment of the inventive process, the alkali metal salts of aminocarboxylate complex- ing agents are selected from alkali metal salts of methylglycine diacetic acid and/or glutamic acid diacetic acid, preferably methylglycine diacetic acid. In one embodiment of the inventive process, the aqueous solution comprises from 40 to 70 % by weight of a complexing agent, more preferred 40 to 65 % by weight of a complexing agent. In another embodiment of the inventive process, the aqueous solution comprises from 0.1 to 30% by weight of organic acid and/or inorganic acid, preferably citric acid, percentages referring to the total respective aqueous solution. more preferred 0.1 to 25 % by weight by weight of or- ganic acid and/or inorganic acid and even more preferred 1 to 20 % by weight by weight of or- ganic acid and/or inorganic acid. The inventive process can be performed at any pressure, for example at a pressure in the range of from 500 mbar to 25 bar. Normal pressure is preferred. The inventive process can be performed in any type of vessel, for example in a stirred tank re- actor or in a pipe with means for dosage of polymer (B), or in a beaker, flask or bottle. In the inventive process, the step of combining an aqueous solution of complexing agent (A) with an inorganic and/or organic acid (B) may be performed in any order. For example, an aqueous solution comprising a complexing agent (A) may be provided, and then an inorganic and/or organic acid (B) is added. In another embodiment, an aqueous solution comprising an inorganic and/or organic acid is provided, and a complexing agent (A) is added. In the context of the present invention, alkali metal salts of aminocarboxylate complexing agents (preferably methylglycine diacetic acid) are selected from lithium salts, potassium salts and pref- erably sodium salts of aminocarboxylate complexing agents (preferably methylglycine diacetic acid). Aminocarboxylate complexing agents (preferably methylglycine diacetic acid) can be par- tially or preferably fully neutralized with the respective alkali. In a preferred embodiment, an average of from 2.5 to 3 COOH groups of methylglycine diacetic acid is neutralized with alkali metal, preferably with sodium. In a particularly preferred embodi- ment, complexing agent (A) is the trisodium salt of MGDA. Likewise, alkali metal salts of glutamic acid diacetic acid are selected from lithium salts, potas- sium salts and preferably sodium salts of glutamic acid diacetic acid. Glutamic acid diacetic acid can be partially or preferably fully neutralized with the respective alkali. In a preferred embodi- ment, an average of from 3.5 to 4 COOH groups of GLDA is neutralized with alkali metal, pref- erably with sodium. In a particularly preferred embodiment, complexing agent (A) is the tetraso- dium salt of GLDA. Complexing agent (A) can be selected from racemic mixtures of alkali metal salts of MGDA or GLDA, and of the pure enantiomers such as alkali metal salts of L-MGDA, alkali metal salts of L-GLDA, alkali metal salts of D-MGDA and alkali metal salts of D-GLDA, and of mixtures of en- antiomerically enriched isomers. In any way, minor amounts of complexing agent (A) may bear a cation other than alkali metal. It is thus possible that minor amounts, such as 0.01 to 5 mol-% of total complexing agent (A) bear alkali earth metal cations such as Mg²⁺ or Ca²⁺, or an Fe²⁺ or Fe³⁺ cation. An object of the present invention are also aqueous solutions, obtainable or obtained by the in- ventive process. Co-Granulates Aqueous solutions according to the invention may further contain a polymer, hereinafter also being referred to as polymer (C), the amount being in the range of from 700 ppm to 7% by weight, preferably 1,000 ppm to 5% by weight, even more preferably up to 2.5% by weight. Pol- ymer (C) may be selected from polyamines, the N atoms being partially or fully substituted with CH₂COOH groups, partially or fully neutralized with alkali metal cations. The term “polyamine” in the context with polymer (C) refers to polymers and copolymers that contain at least one amino group per repeating unit. Said amino group may be selected from NH2 groups, NH groups and preferably tertiary amino groups. In polymer (C), tertiary amino groups are preferred since the basic polyamine has been converted to carboxymethyl deriva- tives, and the N atoms are fully substituted or preferably partially, for example 50 to 95 mol-%, preferably 70 to 90 mol-%, substituted with CH₂COOH groups, partially or fully neutralized with alkali metal cations. In the context of the present invention, such polymers (C) in which more than 95 mol-% to 100 mol-% of the N atoms are substituted with CH₂COOH groups will be con- sidered to be fully substituted with CH₂COOH groups. NH₂ groups from, e. g., polyvinylamines or polyalkylenimines can be substituted with one or two CH₂COOH group(s) per N atom, prefer- ably with two CH₂COOH groups per N atom. The numbers of CH₂COOH groups in polymer (C) divided by the potential total number of CH₂COOH groups, assuming one CH₂COOH group per NH group and two CH₂COOH groups per NH₂ group, will also be termed as “degree of substitution” in the context of the present in- vention. The degree of substitution can be determined, for example, by determining the amine numbers (amine values) of polymer (C) and its respective polyamine before conversion to the CH₂COOH- substituted polymer (C), preferably according to ASTM D2074-07. Examples of polyamines are polyvinylamine, polyalkylenepolyamine and in particular polyalkylenimines such as polypropylenimines and polyethylenimine. Within the context of the present invention, polyalkylenepolyamines are preferably understood as meaning those polymers which comprise at least 6 nitrogen atoms and at least five C2-C10- alkylene units, preferably C2-C3-alkylene units, per molecule, for example pentaethylen- hexamine, and in particular polyethylenimines with 6 to 30 ethylene units per molecule. Within the context of the present invention, polyalkylenepolyamines are to be understood as meaning those polymeric materials which are obtained by homo- or copolymerization of one or more cyclic imines, or by grafting a (co)polymer with at least one cyclic imine. Examples are polyvinylamines grafted with ethylenimine and polyimidoamines grafted with ethylenimine. Preferred polmers (C) are polyalkylenimines such as polyethylenimines and polypropyl- enimines, polyethylenimines being preferred. Polyalkylenimines such as polyethylenimines and polypropylenimines can be linear, essentially linear or branched. In one embodiment of the present invention, polyethylenimines are selected from highly branched polyethylenimines. Highly branched polyethylenimines are characterized by their high degree of branching (DB). The degree of branching can be determined, for example, by ¹³C- NMR spectroscopy, preferably in D2O, and is defined as follows: DB = D +T/D+T+L with D (dendritic) corresponding to the fraction of tertiary amino groups, L (linear) corresponding to the fraction of secondary amino groups and T (terminal) corresponding to the fraction of pri- mary amino groups. Within the context of the present invention, highly branched polyethylenimines are polyethyl- enimines with DB in the range from 0.25 to 0.90. In one embodiment of the present invention, polyethylenimine is selected from highly branched polyethylenimines (homopolymers) with an average molecular weight M_w in the range from 600 to 75000 g/mol, preferably in the range from 800 to 25000 g/mol. In another embodiment of the present invention, polyethylenimines are selected from copoly- mers of ethylenimine, such as copolymers of ethylenimine with at least one diamine with two NH₂ groups per molecule other than ethylenimine, for example propylene imine, or with at least one compound with three NH₂ groups per molecule such as melamine. In one embodiment of the present invention, polymer (C) is selected from branched polyethyl- enimines, partially or fully substituted withCH₂COOH groups, partially or fully neutralized with Na⁺. Within the context of the present invention, polymer (C) is used in covalently modified form, and specifically such that in total up to at most 100 mol-%, preferably in total 50 to 98 mol-%, of the nitrogen atoms of the primary and secondary amino groups of the polymer (C) – percentages being based on total N atoms of the primary and secondary amino groups in polymer (C) – have been reacted with at least one carboxylic acid such as, e. g., Cl-CH₂COOH, or at least one equivalent of hydrocyanic acid (or a salt thereof) and one equivalent of formaldehyde. Within the context of the present application, said reaction (modification) can thus be, for example, an alkylation. Most preferably, up to at most 100 mol-%, preferably in total 50 to 99 mol-%, of the nitrogen atoms of the primary and secondary amino groups of the polymer (C) have been reacted with formaldehyde and hydrocyanic acid (or a salt thereof), for example by way of a Strecker synthesis. Tertiary nitrogen atoms of polyalkylenimine that may form the basis of polymer (C) are generally not bearing a CH₂COOH group. Polymer (C) can, for example, have an average molecular weight (Mn) of at least 500 g/mol; preferably, the average molecular weight of polymer (C) is in the range from 500 to 1,000,000 g/mol, particularly preferably 800 to 50,000 g/mol, determined determination of the amine numbers (amine values), for example according to ASTM D2074-07, of the respective polyamine before alkylation and after and calculation of the respective number of CH₂COOH groups. The molecular weight refers to the respective per-sodium salt. In aqueous solutions according to the invention, the CH₂COOH groups of polymer (C) are partially or fully neutralized with alkali metal cations. The non-neutralized groups COOH can be, for example, the free acid. It is preferred that 90 to 100 mol-% of the CH₂COOH groups of polymer (C) are in neutralized form. It is preferred that the neutralized CH₂COOH groups of polymer (C) are neutralized with the same alkali metal as complexing agent (A). CH₂COOH groups of polymer (C) may be neutralized, partially or fully, with any type of alkali metal cations, preferably with K⁺ and particularly preferably with Na⁺. Aqueous solutions according the invention furthermore contain water. In one embodiment of the present invention, in aqueous solutions according to the invention, the balance of complexing agent (A) and polymer (C), and, optionally, inorganic base, is water. In other embodiments, aqueous solutions according to the invention may contain one or more liquids or solids other than complexing agent (A) and polymer (C) and water. In one embodiment of the present invention, aqueous solutions according to the invention fur- ther comprise (A) in the range of from 1 to 25 % by weight, preferably 3 to 15 % by weight of at least one salt of at least one organic acid, hereinafter also referred to as salt (E). In the context of the present invention, salt (E) is selected from the salts of mono- and dicarbox- ylic acids. Furthermore, salt (E) is different from both complexing agent (A) and polymer (B). In a preferred embodiment of the present invention, salt (E) is selected from alkali metal salts of acetic acid, tartaric acid, lactic acid, maleic acid, fumaric acid, and malic acid. Preferred examples of salt (E) are potassium acetate and sodium acetate, and combinations from potassium acetate and sodium acetate. In one embodiment of the present invention, aqueous solutions according to the invention fur- ther comprise at least one polyethylene glycol with an average molecular weight M_n in the range of from 400 to 10,000 g/mol, hereinafter also being referred to as “polyethylene glycol (D)”, preferably 600 to 6,000 g/mol. In one embodiment of the present invention, polyethylene glycol (D) may be capped, that is con- verted to a polyether, for example with one methyl group per molecule. In another embodiment, polyethylene glycol (D) bears two hydroxyl groups per molecule. In one embodiment of the present invention, aqueous solutions according to the invention may contain in the range of from 1 to 20 % by weight, preferably 5 to 15% by weight of polyethylene glycol (D). The average molecular weight M_n of polyethylene glycol (D) can be determined, for example, by determining the hydroxyl number, preferably according to DIN 53240-1:2012-07. In other embodiments of the present invention, aqueous solutions according to the invention to not contain any polyethylene glycol (D). During transportation of a solution in a pipe and/or in containers, formation of solid precipitates must be avoided. Otherwise, blocking by solids, segregation of the solid resulting in inhomoge- neities of the mixture and product losses by inaccessible solid can occur in a pipe and/or con- tainer. For a transportation in a pipe the solutions have to be stable in the range of several minutes to an hour. For a transportation in a container the solution has to be stable in the range of several days to one week. Thus, the maximum concentration of a solution is limited. Aqueous solutions manufactured according to the inventive process exhibit an extremely low tendency of having solid precipitates of complexing agent (A) or other solids. Therefore, they can be stored and transported in pipes and/or containers without any residue, even at tempera- tures close to the freezing point of the respective aqueous solution according to the invention. Another aspect of the present invention is thus the use of of aqueous solutions according to the invention for transportation in a pipe or a container. Transportation in a pipe or a container in the context of the present invention preferably does not refer to parts of the plant in which complex- ing agent (A) is being manufactured, nor does it refer to storage buildings that form part of the respective production plant in which complexing agent (A) has been manufactured. Containers can, for example, be selected from tanks, bottles, carts, road container, and tank wagons. Pipes can have any diameter, for example in the range of from 5 cm to 1 m, and they can be made of any material which is stable to the alkaline solution of complexing agent (A). Transportation in pipes can also include pumps that form part of the overall transportation system. Another aspect of the present invention is also a process for making a granule or powder of a complexing agent (A), from an inventive aqueous solution or from an aqueous solution obtaina- ble or obtained by the inventive process described herein, said process comprising the steps of (a) providing an inventive aqueous solution or an aqueous solution obtainable or obtained by the inventive process described herein, and (b) optionally adding additional inorganic or organic acid, and/or (c) optionally adding additional amino carboxylate; and/or (d) optionally removing a part of the water from the said solution by evaporation forming a more concentrated solution or slurry and/or (e) optionally adding granule or powder of a complexing agent (A) to said solution forming a slurry and/or (f) optionally heating said solution or slurry to a temperature in the range of from 50 to 120°C, and (g) removing most of the water by an evaporation or drying method selected preferably from kneading dryer, spray granulation and spray drying. The residual moisture of the resulting solid materials is preferable between 0,1 to 30 % (determined by Karl Fischer titration) and more preferably between 0,1 to 20%. Removal of water can be achieved, for example, with the help of membranes or by evaporation. Evaporation of water can be performed by distilling off water, with or without stirring, at tempera- ture in the range of from 20 to 111°C. Removal of water can also be achieved, in one embodi- ment, by evaporating under pressure, e. g. in the range of 1.5 to 10 bar (preferably 1.5 to 5 bar), at a temperature in the range of 100 to 200 °C, preferably 150 to 180° C. Another embodiment of the current invention is a process for making a powder or granule con- taining (A) in the range of from 60 to 99 % by weight of aminocarboxylate in the form of the inventive solution containing at least one complexing agent selected from alkali metal salts of a ami- nocarboxylate complexing agents and at least one organic and/or inorganic acid, (B) in the range of from 1 to 40 % by weight of at least one homo- or copolymer of (meth)acrylic acid, partially or fully neutralized with alkali, percentages referring to the dry content of said powder or granule, said process compris- ing the steps of (a) mixing an inventive aqueous solution comprising in the range of from 30 to 75% by weight of a complexing agent selected from alkali metal salts of an aminocarboxylate complexing agent and in the range of from 0.1 to 40% % by weight of organic acid and/or inorganic acid (preferably citric acid), with at least one homo- or copolymer of (meth)acrylic acid, partially or fully neutralized with alkali, (b) removing most of said water, preferably by spray-drying or spray granulation, preferably using a gas with an inlet temperature of at least 125°C. Polymer (B) mentioned above is selected from homopolymers (B) of (meth)acrylic acid and of copolymers (B) of (meth)acrylic acid, preferably of acrylic acid, partially or fully neutralized with alkali. In the context of the present invention, copolymers (B) are those in which at least 50 mol-% of the comonomers are (meth)acrylic acid, preferably at least 75 mol-%, even more preferably 80 to 99 mol-%. Suitable comonomers for copolymers (B) are ethylenically unsaturated compounds, such as sty- rene, isobutene, ethylene, α-olefins such as propylene, 1-butylene, 1-hexene, and ethylenically unsaturated dicarboxylic acids and their alkali metal salty and anhydrides such as but not lim- ited to maleic acid, fumaric acid, itaconic acid disodium maleate, disodium fumarate, itaconic anhydride, and especially maleic anhydride. Further examples of suitable comonomers are C₁- C4-alkyl esters of (meth)acrylic acid, for example methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate. In one embodiment of the present invention, polymer (B) is selected from copolymers of (meth)acrylic acid and a comonomer bearing at least one sulfonic acid group per molecule. Comonomers bearing at least one sulfonic acid group per molecule may be incorporated into polymer (B) as free acid or least partially neutralized with alkali. Particularly preferred sulfonic- acid-group-containing comonomers are 1-acrylamido-1-propanesulfonic acid, 2-acrylamido-2- propanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methacrylamido-2- methylpropanesulfonic acid, 3-methacrylamido-2-hydroxypropanesulfonic acid, allylsulfonic acid, methallylsulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, 2- hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl-2-propene-1-sulfonic acid, styrenesul- fonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, sulfomethacrylamide, sulfomethylmethacrylamide, and salts of said acids, such as the sodium salts, potassium salts or ammonium salts thereof. Copolymers (B) may be selected from random copolymers, alternating copolymers, block copol- ymers and graft copolymers, alternating copolymers and especially random copolymers being preferred. Useful copolymers (B) are, for example, random copolymers of acrylic acid and methacrylic acid, random copolymers of acrylic acid and maleic anhydride, ternary random copolymers of acrylic acid, methacrylic acid and maleic anhydride, random or block copolymers of acrylic acid and styrene, random copolymers of acrylic acid and methyl acrylate. More preferred are homo- polymers of methacrylic acid. Even more preferred are homopolymers of acrylic acid. Polymer (B) may constitute straight-chain or branched molecules. Branching in this context will be when at least one repeating unit of such polymer (B) is not part of the main chain but forms a branch or part of a branch. Preferably, polymer (B) is not cross-linked. In one embodiment of the present invention, polymer (B) has an average molecular weight Mw in the range of from 1,200 to 30,000 g/mol, preferably from 2,500 to 15,000 g/mol and even more preferably from 3,000 to 10,000 g/mol, determined by gel permeation chromatography (GPC) and referring to the respective free acid. In one embodiment of the present invention, polymer (B) is at least partially neutralized with al- kali, for example with lithium or potassium or sodium or combinations of at least two of the for- going, especially with sodium. For example, in the range of from 10 to 100 mol-% of the car- boxyl groups of polymer (B) may be neutralized with alkali, especially with sodium. In one embodiment of the present invention, polymer (B) is selected from per-sodium salts of polyacrylic acid, thus, polyacrylic acid, fully neutralized with sodium. In one embodiment of the present invention, polymer (B) is selected from a combination of at least one polyacrylic acid and at least one copolymer of (meth)acrylic acid and a comonomer bearing at least one sulfonic acid group per molecule, both polymers being fully neutralized with alkali. In one embodiment of the present invention, polymer (B) is selected from per-sodium salts of polyacrylic acid with an average molecular weight Mw in the range of from 1,200 to 30,000 g/mol, preferably from 2,500 to 15,000 g/mol and even more preferably from 3,000 to 10,000 g/mol, determined by gel permeation chromatography (GPC) and referring to the re- spective free acid. In one embodiment of the present invention, aqueous solutions according to the present inven- tion do not contain any surfactant. In the context of the present invention, “do not contain any surfactant” shall mean that the total content of surfactants is below 0.1 % by weight of the re- spective aqueous solution. In one embodiment of the present invention, complexing agent (A) may contain minor amounts of impurities stemming from its synthesis, such as lactic acid, alanine, propionic acid or the like. “Minor amounts” in this context refer to a total of 0.1 to 1%by weight, referring to complexing agent (A). In one embodiment of the present invention, aqueous solutions according to the invention may have a dynamic viscosity in the range of from 55 to 500 mPa·s, preferably up to 100 mPa·s, de- termined according to DIN 53018-1:2008-09 at 25°C. In one embodiment of the present invention, aqueous solutions according to the invention may have a color number according to Hazen in the range of from 15 to 400, preferably to 360, de- termined according to DIN EN 1557:1997-03 at 25°C. In one embodiment of the present invention, aqueous solutions according to the present inven- tion have a total dry contentin the range of from 30.01 to 65% by weight Inventive aqueous solutions, powders and/or granules are excellently suited for the manufacture of laundry detergents or cleaners. Another aspect of the present invention is therefore the use of inventive aqueous solutions, powders and/or granules for the manufacture of a cleaning agent that may contain at least one bleaching agent, and in particular for the manufacture of cleaning agent for fibers or hard sur- faces, wherein said cleaning agent contains at least one peroxy compound. Another aspect of the present invention is a process for making at a cleaning agent by combining inventive aque- ous solutions, powders and/or granules with at least one bleaching agent, preferably at least one peroxy compound. Another aspect of the present invention is a cleaning agent, hereinafter also being referred to as inventive cleaning agent. Inventive cleaning agents may contain at least one bleaching agent and inventive aqueous solu- tions, powders and/or granules. Inventive cleaning agents show a reduced tendency for yellow- ing and therefore have an extended shelf-life. Examples of suitable peroxy compounds are sodium perborate, anhydrous or for example as monohydrate or as tetrahydrate or so-called dihydrate, sodium percarbonate, anhydrous or, for example, as monohydrate, hydrogen peroxide, persulfates, organic peracids such as peroxylau- ric acid, peroxystearic acid, peroxy-α-naphthoic acid, 1,12-diperoxydodecanedioic acid, per- benzoic acid, peroxylauric acid, 1,9-diperoxyazelaic acid, diperoxyisophthalic acid, in each case as free acid or as alkali metal salt, in particular as sodium salt, also sulfonylperoxy acids and cationic peroxy acids. In a preferred embodiment, peroxy compound is selected from inorganic percarbonates, persul- fates and perborates. Examples of sodium percarbonates are 2 Na₂CO₃·3 H₂O₂. Examples of sodium perborate are (Na₂[B(OH)₂(O₂)]₂), sometimes written as NaBO₂·O₂·3H₂O instead. Most preferred peroxy compound is sodium percarbonate. The term “cleaning agents” includes compositions for dishwashing, especially hand dishwash and automatic dishwashing and ware-washing, and compositions for hard surface cleaning such as, but not limited to compositions for bathroom cleaning, kitchen cleaning, floor cleaning, de- scaling of pipes, window cleaning, car cleaning including truck cleaning, furthermore, open plant cleaning, cleaning-in-place, metal cleaning, disinfectant cleaning, farm cleaning, high pressure cleaning, and in addition, laundry detergent compositions. Such cleaning agents may be liquids, gels or preferably solids at ambient temperature, solids cleaning agents being preferred. They may be in the form of a powder or in the form of a unit dose, for example as a tablet. In one embodiment of the present invention, inventive cleaning agents may contain in the range of from 2 to 50 % by weight of inventive aqueous solutions, powders and/or gran- ules, in the range of from 0.5 to 15 % by weight of bleach. Percentages are based on the dry content of the respective inventive cleaning agent. Inventive cleaning agents may contain further ingredients such as one or more surfactants that may be selected from non-ionic, zwitterionic, cationic, and anionic surfactants. Other ingredients that may be contained in inventive cleaning agents may be selected from bleach activators, bleach catalysts, corrosion inhibitors, sequestering agents other than chelating agent (A), en- zymes, fragrances, dyestuffs, antifoams, and builders. Particularly advantageous inventive cleaning agents may contain one or more complexing agents other than MGDA or GLDA. Advantageous detergent compositions for cleaners and ad- vantageous laundry detergent compositions may contain one or more sequestrant (chelating agent) other than a mixture according to the present invention. Examples for sequestrants other than a mixture according to the present invention are IDS (iminodisuccinate), citrate, phos- phonic acid derivatives, for example the disodium salt of hydroxyethane-1,1-diphosphonic acid (“HEDP”), and polymers with complexing groups like, for example, polyethyleneimine in which 20 to 90 mole-% of the N-atoms bear at least one CH₂COO- group, and their respective alkali metal salts, especially their sodium salts, for example IDS-Na₄, and trisodium citrate, and phos- phates such as STPP (sodium tripolyphosphate). Due to the fact that phosphates raise environ- mental concerns, it is preferred that advantageous inventive cleaning agents are free from phosphate. "Free from phosphate" should be understood in the context of the present invention, as meaning that the content of phosphate and polyphosphate is in sum in the range from 10 ppm to 0.2% by weight, determined by gravimetric methods and referring to the respective in- ventive cleaning agent. Inventive cleaning agents may contain one or more surfactant, preferably one or more non-ionic surfactant. Preferred non-ionic surfactants are alkoxylated alcohols, di- and multiblock copolymers of eth- ylene oxide and propylene oxide and reaction products of sorbitan with ethylene oxide or propyl- ene oxide, alkyl polyglycosides (APG), hydroxyalkyl mixed ethers and amine oxides. Preferred examples of alkoxylated alcohols and alkoxylated fatty alcohols are, for example, compounds of the general formula (II)

in which the variables are defined as follows: R¹ is identical or different and selected from hydrogen and linear C₁-C₁₀-alkyl, preferably in each case identical and ethyl and particularly preferably hydrogen or methyl, R² is selected from C₈-C₂₂-alkyl, branched or linear, for example n-C₈H₁₇, n-C₁₀H₂₁, n-C₁₂H₂₅, n-C₁₄H₂₉, n-C₁₆H₃₃ or n-C₁₈H₃₇, R³ is selected from C₁-C₁₀-alkyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl or isodecyl, m and n are in the range from zero to 300, where the sum of n and m is at least one, preferably in the range of from 3 to 50. Preferably, m is in the range from 1 to 100 and n is in the range from 0 to 30. In one embodiment, compounds of the general formula (II) may be block copolymers or random copolymers, preference being given to block copolymers. Other preferred examples of alkoxylated alcohols are, for example, compounds of the general formula (III)

in which the variables are defined as follows: R¹ is identical or different and selected from hydrogen and linear C₁-C₀-alkyl, preferably iden- tical in each case and ethyl and particularly preferably hydrogen or methyl, R⁴ is selected from C₆-C₂₀-alkyl, branched or linear, in particular n-C₈H₁₇, n-C₁₀H₂₁, n-C₁₂H₂₅, n-C₁₄H₂₉, n-C₁₆H₃₃, n-C₁₈H₃₇, a is a number in the range from zero to 10, preferably from 1 to 6, b is a number in the range from 1 to 80, preferably from 4 to 20, d is a number in the range from zero to 50, preferably 4 to 25. The sum a + b + d is preferably in the range of from 5 to 100, even more preferably in the range of from 9 to 50. Preferred examples for hydroxyalkyl mixed ethers are compounds of the general formula (IV)

in which the variables are defined as follows: R¹ is identical or different and selected from hydrogen and linear C₁-C₁₀-alkyl, preferably in each case identical and ethyl and particularly preferably hydrogen or methyl, R² is selected from C₈-C₂₂-alkyl, branched or linear, for example iso-C₁₁H₂₃, iso-C₁₃H₂₇, n- C₈H₁₇, n-C₁₀H₂₁, n-C₁₂H₂₅, n-C₁₄H₂₉, n-C₁₆H₃₃ or n-C₁₈H₃₇, R³ is selected from C₁-C₁₈-alkyl, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, isodecyl, n-dodecyl, n-tetradecyl, n-hexadecyl, and n-octadecyl. The variables m and n are in the range from zero to 300, where the sum of n and m is at least one, preferably in the range of from 5 to 50. Preferably, m is in the range from 1 to 100 and n is in the range from 0 to 30. Compounds of the general formula (II) and (III) may be block copolymers or random copoly- mers, preference being given to block copolymers. Further suitable nonionic surfactants are selected from di- and multiblock copolymers, com- posed of ethylene oxide and propylene oxide. Further suitable nonionic surfactants are selected from ethoxylated or propoxylated sorbitan esters. Amine oxides or alkyl polyglycosides, espe- cially linear C₄-C₁₆-alkyl polyglucosides and branched C₈-C₁₄-alkyl polyglycosides such as com- pounds of general average formula (V) are likewise suitable.

wherein the variables are defined as follows: R⁵ is C₁-C₄-alkyl, in particular ethyl, n-propyl or isopropyl, R⁶ is -(CH₂)₂-R⁵, G¹ is selected from monosaccharides with 4 to 6 carbon atoms, especially from glucose and xylose, y in the range of from 1.1 to 4, y being an average number. Further examples of non-ionic surfactants are compounds of general formula (VII) and (VIII)

AO is selected from ethylene oxide, propylene oxide and butylene oxide, EO is ethylene oxide, CH₂CH₂-O, R⁸ selected from C₈-C₁₈-alkyl, branched or linear, and R⁵ is defined as above. A³O is selected from propylene oxide and butylene oxide, w is a number in the range of from 15 to 70, preferably 30 to 50, w1 and w3 are numbers in the range of from 1 to 5, and w2 is a number in the range of from 13 to 35. An overview of suitable further nonionic surfactants can be found in EP-A 0851023 and in DE- A 19819187. Mixtures of two or more different nonionic surfactants may also be present. Other surfactants that may be present are selected from amphoteric (zwitterionic) surfactants and anionic surfactants and mixtures thereof. Examples of amphoteric surfactants are those that bear a positive and a negative charge in the same molecule under use conditions. Preferred examples of amphoteric surfactants are so- called betaine-surfactants. Many examples of betaine-surfactants bear one quaternized nitrogen atom and one carboxylic acid group per molecule. A particularly preferred example of ampho- teric surfactants is cocamidopropyl betaine (lauramidopropyl betaine). Examples of amine oxide surfactants are compounds of the general formula (IX) R⁷R⁸R⁹N→O (IX) wherein R⁷, R⁸ and R⁹ are selected independently from each other from aliphatic, cycloaliphatic or C₂-C₄-alkylene C₁₀-C₂₀-alkylamido moieties. Preferably, R⁷ is selected from C₈-C₂₀-alkyl or C₂- C₄-alkylene C₁₀-C₂₀-alkylamido and R⁸ and R⁹ are both methyl. A particularly preferred example is lauryl dimethyl aminoxide, sometimes also called lauramine oxide. A further particularly preferred example is cocamidylpropyl dimethylaminoxide, some- times also called cocamidopropylamine oxide. Examples of suitable anionic surfactants are alkali metal and ammonium salts of C₈-C₁₈-alkyl sulfates, of C₈-C₁₈-fatty alcohol polyether sulfates, of sulfuric acid half-esters of ethoxylated C4- C₁₂-alkylphenols (ethoxylation: 1 to 50 mol of ethylene oxide/mol), C₁₂-C₁₈ sulfo fatty acid alkyl esters, for example of C₁₂-C₁₈ sulfo fatty acid methyl esters, furthermore of C₁₂-C₁₈-alkylsulfonic acids and of C10-C₁₈-alkylarylsulfonic acids. Preference is given to the alkali metal salts of the aforementioned compounds, particularly preferably the sodium salts. Further examples for suitable anionic surfactants are soaps, for example the sodium or potas- sium salts of stearoic acid, oleic acid, palmitic acid, ether carboxylates, and alkylether phos- phates. Preferably, laundry detergent compositions contain at least one anionic surfactant. In one embodiment of the present invention, inventive cleaning agents that are determined to be used as laundry detergent compositions may contain 0.1 to 60 % by weight of at least one sur- factant, selected from anionic surfactants, amphoteric surfactants and amine oxide surfactants. In one embodiment of the present invention, inventive cleaning agents that are determined to be used for hard surface cleaning may contain 0.1 to 60 % by weight of at least one surfactant, se- lected from anionic surfactants, amphoteric surfactants and amine oxide surfactants. In a preferred embodiment, inventive cleaning agents do not contain any anionic detergent. Inventive cleaning agents may comprise one or more bleach catalysts. Bleach catalysts can be selected from bleach-boosting transition metal salts or transition metal complexes such as, for example, manganese-, iron-, cobalt-, ruthenium- or molybdenum-salen complexes or carbonyl complexes. Manganese, iron, cobalt, ruthenium, molybdenum, titanium, vanadium and copper complexes with nitrogen-containing tripod ligands and also cobalt-, iron-, copper- and ruthe- nium-amine complexes can also be used as bleach catalysts. Inventive cleaning agents may comprise one or more bleach activators, for example N-methyl- morpholinium-acetonitrile salts (“MMA salts”), trimethylammonium acetonitrile salts, N- acylimides such as, for example, N-nonanoylsuccinimide, 1,5-diacetyl-2,2-dioxohexahydro- 1,3,5-triazine (“DADHT”) or nitrile quats (trimethylammonium acetonitrile salts). Further examples of suitable bleach activators are tetraacetylethylenediamine (TAED) and tetraacetylhexylenediamine. Inventive cleaning agents may comprise one or more corrosion inhibitors. In the present case, this is to be understood as including those compounds which inhibit the corrosion of metal. Ex- amples of suitable corrosion inhibitors are triazoles, in particular benzotriazoles, bisbenzotria- zoles, aminotriazoles, alkylaminotriazoles, also phenol derivatives such as, for example, hydro- quinone, pyrocatechol, hydroxyhydroquinone, gallic acid, phloroglucinol or pyrogallol. In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.1 to 1.5% by weight of corrosion inhibitor. Inventive cleaning agents may comprise one or more builders, selected from organic and inor- ganic builders. Examples of suitable inorganic builders are sodium sulfate or sodium carbonate or silicates, in particular sodium disilicate and sodium metasilicate, zeolites, sheet silicates, in particular those of the formula α-Na₂Si₂O₅, β- Na₂Si₂O,₅ and δ-Na₂Si₂O₅, also fatty acid sul- fonates, α-hydroxypropionic acid, alkali metal malonates, fatty acid sulfonates, alkyl and alkenyl disuccinates, tartaric acid diacetate, tartaric acid monoacetate, oxidized starch, and polymeric builders, for example polycarboxylates and polyaspartic acid. Examples of organic builders are especially polymers and copolymers other such as (co)poly- mers (B) and include polymers and copolymers than (co)polymer (B), or one additional (co)poly- mer (B). In one embodiment of the present invention, organic builders are selected from poly- carboxylates, for example alkali metal salts of (meth)acrylic acid homopolymers or (meth)acrylic acid copolymers, partially or completely neutralized with alkali. Suitable comonomers for (meth)acrylic acid are monoethylenically unsaturated dicarboxylic ac- ids such as maleic acid, fumaric acid, maleic anhydride, itaconic acid and citraconic acid. A suit- able polymer is in particular polyacrylic acid, which preferably has an average molecular weight M_w in the range from 2000 to 40000 g/mol, preferably 2000 to 10000 g/mol, in particular 3000 to 8000 g/mol. Also of suitability are copolymeric polycarboxylates, in particular those of acrylic acid with methacrylic acid and of acrylic acid or methacrylic acid with maleic acid and/or fumaric acid, and in the same range of molecular weight. It is also possible to use copolymers of at least one monomer from the group consisting of mo- noethylenically unsaturated C₃-C₁₀-mono- or C₄-C₁₀-dicarboxylic acids or anhydrides thereof, such as maleic acid, maleic anhydride, acrylic acid, methacrylic acid, fumaric acid, itaconic acid and citraconic acid, with at least one hydrophilic or hydrophobic monomer as listed below. Suitable hydrophobic monomers are, for example, isobutene, diisobutene, butene, pentene, hexene and styrene, olefins with 10 or more carbon atoms or mixtures thereof, such as, for ex- ample, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 1-do- cosene, 1-tetracosene and 1-hexacosene, C₂₂-α-olefin, a mixture of C₂₀- C₂₄-α-olefins and poly- isobutene having on average 12 to 100 carbon atoms per molecule. Suitable hydrophilic monomers are monomers with sulfonate or phosphonate groups, and also nonionic monomers with hydroxyl function or alkylene oxide groups. By way of example, men- tion may be made of: allyl alcohol, isoprenol, methoxypolyethylene glycol (meth)acrylate, meth- oxypolypropylene glycol (meth)acrylate, methoxypolybutylene glycol (meth)acrylate, methoxy- poly(propylene oxide-co-ethylene oxide) (meth)acrylate, ethoxypolyethylene glycol (meth)acry- late, ethoxypolypropylene glycol (meth)acrylate, ethoxypolybutylene glycol (meth)acrylate and ethoxypoly(propylene oxide-co-ethylene oxide) (meth)acrylate. Polyalkylene glycols here may comprise 3 to 50, in particular 5 to 40 and especially 10 to 30 alkylene oxide units per molecule. Particularly preferred sulfonic-acid-group-containing monomers here are 1-acrylamido-1-pro- panesulfonic acid, 2-acrylamido-2-propanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 3-methacrylamido-2-hydroxypropanesul- fonic acid, allylsulfonic acid, methallylsulfonic acid, allyloxybenzenesulfonic acid, methallyloxybenzenesulfonic acid, 2-hydroxy-3-(2-propenyloxy)propanesulfonic acid, 2-methyl- 2-propene-1-sulfonic acid, styrenesulfonic acid, vinylsulfonic acid, 3-sulfopropyl acrylate, 2-sul- foethyl methacrylate, 3-sulfopropyl methacrylate, sulfomethacrylamide, sulfomethylmethacryla- mide, and salts of said acids, such as sodium, potassium or ammonium salts thereof. Particularly preferred phosphonate-group-containing monomers are vinylphosphonic acid and its salts. A further example of builders is carboxymethyl inulin. Moreover, amphoteric polymers can also be used as builders. Inventive cleaning agents may comprise, for example, in the range from in total 10 to 70% by weight, preferably from in total 10 to 50% by weight, more preferably up to 20% by weight, of builder. In one embodiment of the present invention, inventive cleaning agents according to the inven- tion may comprise one or more co-builders. Inventive cleaning agents may comprise one or more antifoams, selected for example from sili- cone oils and paraffin oils. In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.05 to 0.5% by weight of antifoam. Inventive cleaning agents may comprise one or more enzymes. Examples of enzymes are li- pases, hydrolases, amylases, proteases, cellulases, esterases, pectinases, lactases and peroxi- dases. In one embodiment of the present invention, inventive cleaning agents may comprise, for exam- ple, up to 5% by weight of enzyme, preference being given to 0.1 to 3% by weight. Said enzyme may be stabilized, for example with the sodium salt of at least one C₁-C₃-carboxylic acid or C₄- C₁₀-dicarboxylic acid. Preferred are formates, acetates, adipates, and succinates. In one embodiment of the present invention, inventive cleaning agents may comprise at least one zinc salt. Zinc salts can be selected from water-soluble and water-insoluble zinc salts. In this connection, within the context of the present invention, water-insoluble is used to refer to those zinc salts which, in distilled water at 25°C, have a solubility of 0.1 g/l or less. Zinc salts which have a higher solubility in water are accordingly referred to within the context of the pre- sent invention as water-soluble zinc salts. In one embodiment of the present invention, zinc salt is selected from zinc benzoate, zinc glu- conate, zinc lactate, zinc formate, ZnCl₂, ZnSO₄, zinc acetate, zinc citrate, Zn(NO₃)₂, Zn(CH₃SO₃)₂ and zinc gallate, preferably ZnCl₂, ZnSO₄, zinc acetate, zinc citrate, Zn(NO₃)₂, Zn(CH₃SO₃)₂ and zinc gallate. In another embodiment of the present invention, zinc salt is selected from ZnO, ZnO·aq, Zn(OH)₂ and ZnCO₃. Preference is given to ZnO·aq. In one embodiment of the present invention, zinc salt is selected from zinc oxides with an aver- age particle diameter (weight-average) in the range from 10 nm to 100 µm. The cation in zinc salt can be present in complexed form, for example complexed with ammonia ligands or water ligands, and in particular be present in hydrated form. To simplify the notation, within the context of the present invention, ligands are generally omitted if they are water lig- ands. Depending on how the pH value of mixture according to the invention is adjusted, zinc salt can change. Thus, it is for example possible to use zinc acetate or ZnCl2 for preparing formulation according to the invention, but this converts at a pH of 8 or 9 in an aqueous environment to ZnO, Zn(OH)2 or ZnO·aq, which can be present in non-complexed or in complexed form. Zinc salt may be present in those inventive cleaning agents that are solid at room temperature. In such inventive cleaning agents zinc salts are preferably present in the form of particles which have for example an average diameter (number-average) in the range from 10 nm to 100 µm, preferably 100 nm to 5 µm, determined for example by X-ray scattering. Zinc salt may be present in those inventive cleaning agents that are liquid at room temperature. In such inventive cleaning agents zinc salts are preferably present in dissolved or in solid or in colloidal form. In one embodiment of the present invention, inventive cleaning agents comprise in total in the range from 0.05 to 0.4% by weight of zinc salt, based in each case on the dry content of the cleaning agent in question. Here, the fraction of zinc salt is given as zinc or zinc ions. From this, it is possible to calculate the counterion fraction. In one embodiment of the present invention, inventive cleaning agents are free from heavy met- als apart from zinc compounds. Within the context of the present, this may be understood as meaning that inventive cleaning agents are free from those heavy metal compounds which do not act as bleach catalysts, in particular of compounds of iron and of bismuth. Within the context of the present invention, "free from" in connection with heavy metal compounds is to be under- stood as meaning that the content of heavy metal compounds which do not act as bleach cata- lysts is in sum in the range from 0 to 100 ppm, determined by the leach method and based on the dry content. Preferably, inventive cleaning agents has, apart from zinc, a heavy metal con- tent below 0.05 ppm, based on the dry content of the formulation in question. The fraction of zinc is thus not included. Within the context of the present invention, "heavy metals" are deemed to be all metals with a specific density of at least 6 g/cm³ with the exception of zinc. In particular, the heavy metals are metals such as bismuth, iron, copper, lead, tin, nickel, cadmium and chromium. Preferably, inventive cleaning agents comprise no measurable fractions of bismuth compounds, for example less than 1 ppm. Inventive cleaning agents are excellent for cleaning hard surfaces and fibres. For example, they may be used in dishwashing applications, preferably automatic dishwashing applications. In one embodiment of the present invention, inventive cleaning agents comprise one or more further ingredient such as fragrances, dyestuffs, organic solvents, buffers, disintegrants for tab- lets (“tabs”), and/or acids such as methylsulfonic acid. From inventive aqueous solutions, granules or powders, examplary detergent compositions for automatic dishwashing detergents can be formulated by mixing the respective components ac- cording to the following Table F. Table F: Example detergent compositions for automatic dishwashing

Laundry detergents according to the invention are useful for laundering any type of laundry, and any type of fibres. Fibres can be of natural or synthetic origin, or they can be mixtures of natural of natural and synthetic fibres. Examples of fibers of natural origin are cotton and wool. Exam- ples for fibers of synthetic origin are polyurethane fibers such as Spandex® or Lycra®, polyester fibers, or polyamide fibers. Fibers may be single fibers or parts of textiles such as knitwear, wovens, or nonwovens. Another aspect of the present invention is a process for making tablets for automatic dishwash- ing from a powder or granule, wherein said granule or powder is selected from inventive gran- ules and inventive powders, respectively. Said process is hereinafter also referred to as pelletiz- ing process according to the invention. Inventive tablets are preferably made with the help of a machine, for example a tablet press. The pelletizing process according to the invention can be carried out by mixing inventive gran- ule or powder with at least one non-ionic surfactant and optionally one or more further sub- stance and then compressing the mixture to give tablets. Examples of suitable non-ionic surfac- tants and further substances such as builders, enzymes are listed above. Particularly preferred examples of non-ionic surfactants are hydroxy mixed ethers, for example hydroxy mixed ethers of the general formula (V). The invention is further illustrated by the following working examples. Working examples Percentages refer to % by weight unless expressly noted otherwise. Examples: Salt (A.1): MGDA-Na₃ (e.e. of 24%, determined by HPLC with penicillamine as chiral modifica- tion agent), provided as (A.1a) 40% by weight aqueous solution of salt (A.1) having a total dry content of 43.5% by weight (determined by drying the said solution for 60min at 200°C), purchased from BASF, and as (A.1b) 79.2% by weight powder of salt (A.1) having a total dry content of 88.0% by weight, where powder is of at least 75% by weight the orthorhombic salt (A.1), referring to the entire content of (A.1b). (A.1c) 80% by weight powder of salt (A.1) having a total dry content of 88.0% by weight, where powder is of at least 75% by weight the monoclinic salt (A.1), referring to the entire content of (A.1c). (A.1c resembles a customary sale product available on the market.) The dry content was determined by drying the said solution for 60min at 200°C on a drying bal- ance. The percentages of orthorhombic salt (A.1) in (A.1b) were determined by X-ray diffraction. The X ray powder diffractometer measurements were carried out on a D8 Advance® diffractom- eter from Bruker AXS (Karlsruhe). In reflection with Cu-K α radiation was measured with a varia- ble diaphragm adjustment on the primary side and on the secondary side. The measurement range was 2° to 80° 2-theta, the step width 0.01° and the measurement time per angle step 3.6 seconds. Based on the software TOPAS from Bruker optics, the relative amounts of the poly- morphic form of (A.1) were determined. Example 1: Clear-Point concentration of inventive solution of salt (A.1) Step (a.1): in step (a.1), 0.1 kg of a 40% by weight solution (A.1a) was filled into a glass bottle and was stirred at ambient temperature. One inorganic or organic acid was added to the stirred solution (see table 1). The mixture was inspected by eyes and it was waited until the solution became a clear solution without turbidity or particles. In a following step, crystalline salt (A.1b) was added until the concentration of salt (A.1) was increased by 0.3% by weight and the mix- ture was inspected by eyes. It must be mentioned that this example was performed adding (A.1b), containing at least 75% by weight of the orthorhombic crystal of salt (A.1), instead of adding the monoclinic crystal of salt (A.1). Experiments with monoclinic salt (A.1) would result into different solubilities, since it is trivial that different forms of crystals have different solubility. As soon as the solution became a clear solution without turbidity or particles, this step was repeated several times. When the solu- tion did not become a clear solution without turbidity or particles again after 24 hours stirring at ambient temperature, the experiment was over and the concentration before the last addition of (A.1b) is the clear-point concentration. The clear-point concentration in the presence of the re- spective inorganic or organic acid is shown in Table 1. The clear-point concentration of salt (A.1) in the presence of the selected acid is increased and higher than 40% by weight in com- parison to the original solution. The clear-point concentration of total dry content in the presence of the selected acid is increased and higher than 43.5% by weight in comparison to the original solution. Table 1: Clear-point concentration of aqueous solution of salt (A.1) in the presence of one inor- ganic or organic acid at ambient temperature and ambient pressure.

Example 2: Stability of inventive solution of salt (A.1) Step (a.2): in step (a.2), 0.5 kg of a 40% by weight solution (A.1a) was filled into a glass flask at ambient temperature. Afterwards, water was removed by evaporation at 70°C under vacuum con- ditions (220 mbar) over one hour until a concentrated solution of salt (A.1) according to table 2 and 3 is received. For each concentration of salt (A.1), step (a.2) was repeated. The flask was rotating 15 rpm during evaporation. Step (b.2): in step (b.2), the so obtained solution at 70°C was split in samples of 100 g each. This step is followed either by step (c.2a) or step (c.2b) or step (c.2c). Step (c.2a): in step (c.2a), one sample obtained from (b.2) of each concentration of salt (A.1) were stirred at ambient temperature over a period of seven days. Then, the appearance of the test solution was inspected by visual inspection. These samples were used as comparative samples (C). The results are summarized in table 2. Step (c.2b): in step (c.2b), the respective inorganic or organic acid according to table 2 was mixed under 15 minutes of stirring into the solutions obtained from step (b.2). The so obtained test so- lutions of a salt (A.1) and one added acid according to table 2 were stirred at ambient temperature over a period of seven days. Then, the appearance of the test solution was inspected by visual inspection. The results are summarized in table 2. Table 2: Appearance of test solutions from step (c.2a) and step (c.2b) after seven days.

Step (c.2c): in step (c.2c), the respective inorganic or organic acid according to table 3 was mixed under 15 minutes of stirring into a 50% by weight solution of salt (A.1) obtained from step (b.2). The so obtained very high concentrated test solutions of a salt (A.1) and one added acid according to table 3 were stirred at ambient temperature over a period of one hour. Then, the appearance of the test solution was inspected by visual inspection. The results are summarized in table 3. Table 3: Appearance of test solutions from step (c.2c) after one hour.

Example 3: Crystallization from inventive solution of salt (A.1) Step (a.3): A crystallizer with stirrer and baffles was charged with 5.0 kg of a 40% by weight so- lution (A.1a). Citric acid was charged with 2% by weight. The solution was concentrated to 46% of salt (A.1) by weight by evaporation at 70°C and 220 mbar. Step (b.3): The solution was maintained at 70°C with stirring at 450 rpm. Then, under stirring, 10 g (0.5 % of salt (A.1) in solution) of salt (A.1b) were added to the solution in the crystallizer. The resultant slurry was stirred for 20 minutes and subsequently was concentrated to 52% by weight of salt (A.1) by vacuum evaporation at 70°C and 220 mbar in 4 hours. The resultant slurry was stirred at 70°C with 450 rpm for 3 hours. Slurry SL.3 was obtained. Afterwards, either step (c.3a) or (c.3b) was performed. Step (c.3a): SL.3 was discharged and dried at 70°C and vacuum for 12 hours in a rotating glass flask. Solid sample from crystallization from inventive solution of salt (A.1) S.3a was obtained. Step (c.3b): SL.3 was discharged and filtered with a centrifuge at 70° C to separate the mother liquor from the solid. A wet filter cake was obtained. The filter cake was dried at 70°C and vac- uum for 12 hours in a rotating glass flask. Solid sample from crystallization and filtration from in- ventive solution of salt (A.1) S.3b was obtained. Testing of inventive granules and of comparative granule Test protocol: 10 g of inventive granule or of A.1b were mixed with 5 g Na-percarbonate and placed in a vial having a permeable stopper to allow an exchange with the surrounding atmos- phere. The vial was stored for 28 days in a climate-chamber at 35°C and 70% humidity. The discoloration of the above stored mixtures was determined by measuring the b-value of the CIELAB color space (Mach 5 measurement). Table 4. Yellowing behavior of inventive granules and of comparative granule A.1c

Example 4: Manufacture of inventive granule from inventive solutions Example 4.I: Manufacture of inventive granules 4.I.1 Manufacture of spray solution SL.1 A vessel was charged with 18,8 kg of an aqueous solution of Trilon M (40 % by weight MGDA content), 2,9 kg Trilon M granules and 0,22 kg of citric acid monohydrate. The solution SL.1 so obtained was stirred heated to 70°C, the citric acid monohydrate dissolved and then subjected to spray granulation. 4.I.2 Spray granulation of Spray Liquor SL.1 A lab scale granulator, commercially available as Glatt Procell Lab System with Vario 3 Insert, was charged with 0.9 kg of solid MGDA-Na3 spherical particles, diameter 350 to 1000 µm (com- mercially available as Trilon M max granules), and 600 g of milled MGDA-Na3 particles. An amount of 200 Nm³/h of air with a temperature of 165-175°C was blown from the bottom. A flu- idized bed of MGDA-Na₃ particles was obtained. The above liquor SL.1 was introduced by spraying 7 kg of SL.1 per hour (70°C) into the fluidized from the bottom through a two-fluid noz- zle, absolute pressure in the nozzle: 4,35 bar. Granules were formed, and the bed temperature, which corresponds to the surface temperature of the solids in the fluidized bed, was 98-101. Continuously, particles, which are large (heavy) enough fall through the zigzag air classifier (op- erated at 1.8-2,3 bar relative pressure) into a sample bottle. The smaller (lighter) granules were blown through the recycle back into the fluidized bed by the air classifier. When about 1L of granules were collected in the sample bottle, the bottle is replaced by a new sample bottle. The collected granules were subjected to a sieving step. The mesh size of the sieve is 1mm. Two fractions were obtained: coarse particles (diameter > 1mm) and value frac- tion (<1mm). Coarse particles (diameter > 1mm), were milled down together with small amounts of value fraction using a hammer mill (Kinetatica Polymix PX-MFL 90D) at 4000 rpm (rounds per minute), 2 mm mesh. The powder so obtained was returned into the fluidized bed. The major part of the value fraction, which was not milled down, left the process and was collected. After 8 kg of sprayed liquid a steady state was reached. Then, the fraction <1mm was collected as inventive granules Gr.1. The residual moisture of Gr.1 was determined to be between 11 an 13 wt%, referring to a total dry content of 87 to 89 wt% of the granule. In the above example, hot air of can be replaced by hot N₂ having a temperature. 4.II.1 Manufacture of spray solution SL.2 A vessel was charged with 18,6 kg of an aqueous solution of Trilon M (40 % by weight MGDA content), 2,9 kg Trilon M granules and 0,56 kg of citric acid monohydrate. The solution SL.2 so obtained was stirred heated to 70°C, the citric acid monohydrate dissolved and then subjected to spray granulation. 4.II.2 Spray granulation of Spray Liquor SL.2 The granulation step took place the same way as described in example I, step I.2, but using SL.2 instead of SL.1. The granules so obtained were named Gr.2 4.III.1 Manufacture of spray solution SL.3 A vessel was charged with 2,5 kg Trilon M max liquid, 0,39 kg Trilon M granules and 0,03 kg cit- ric acid monohydrate and 0,08 kg Sokalan Pa25CL granules. The solution SL.3 so obtained was stirred heated to 70°C, the citric acid monohydrate and the Sokalan PA25CL dissolved and then subjected to spray granulation. A lab scale granulator, commercially available as “WFP-Mini” from the company DMR, was charged with 300g of solid Trilon M max granules that were milled down using a Kinetatica Polymix PX-MFL 90D) at 4000 rpm (rounds per minute), 2 mm mesh. An amount of 23- 24Nm3/h of nitrogen with a temperature of 140-160°C was blown from the bottom. A fluidized bed of Trilon M particles was obtained. The above liquor SL.3 was introduced by spraying about 15g/minute SL.3 (at 70°C) into the fluidized from the bottom through a three-fluid nozzle. The pressure of the atomizing gas was 2.5 to 3.0 bar, abs. Granules were formed, and the bed tem- perature, which corresponds to the surface temperature of the solids in the fluidized bed, was 99-103°C. Every 15-20 minutes an aliquot of granule (150-250g) is removed from the vessel and classified by sieving. Three fractions were obtained: coarse particles (diameter > 1mm), value fraction (di- ameter >350µm and <1mm) and fines (diameter <350µm). The coarse particles (diameter > 1mm), were milled down using a hammer mill (Kinetatica Polymix PX-MFL 90D) at 4000 rpm (rounds per minute), 2 mm mesh. The powder so obtained, and the fines were returned into the fluidized bed. The value fraction, which was not milled down, left the process and was collected. After 2kg of sprayed liquid, a steady state was reached. Then, the value fraction was collected as inventive granules Gr.3. In the above example, nitrogen can be replaced by air having the same temperature. 4.IV.1 Manufacture of spray solution SL.4 A vessel was charged with 2,5 kg Trilon M max liquid, 0,39 kg Trilon M granules and 0,03 kg cit- ric acid monohydrate and 0,09 kg Sokalan CP50 granules. The solution SL.4 so obtained was stirred heated to 70°C, the citric acid monohydrate and the Sokalan PA25CL dissolved and then subjected to spray granulation. 4.IV.1 Spray granulation of Spray Liquor SL.4 The granulation step took place the same way as described in example III, step III.2, but using SL.4 instead of SL.3. The granules so obtained were named Gr.4

Claims

Claims 1. Process for making an aqueous solution, preferably with a total dry content of at least 45%, comprising (A) in the range of from 30 to 75 % by weight of alkali metal salts of methylglycine di- acetic acid , and (B) in the range of from 0.1 to 40 % by weight of organic acid and/or inorganic acid, preferably organic acid, in acidic form, partially deprotonated form, or fully deproto- nated form percentages referring to the total respective aqueous solution, comprising the step of combining an aqueous solution of complexing agent (A) with an inorganic and/or organic acid (B).

2. Process for making an aqueous solution according to claim 1, having a pH value in the range of from 1 to 13, preferably 4 to 11.

3. Process for making an aqueous solution according to any of the preceding claims, wherein the organic acid is chosen from any di- or tricarboxylic acid or any polycarboxylic acid, preferably citric acid.

4. Process for making an aqueous solution according to any of the preceding claims, wherein the inorganic acid is chosen from any inorganic acid, preferably H₂SO₄, HCl or CO₂.

5. Process for making an aqueous solution according to any of the preceding claims, wherein an organic acid is used and wherein the organic acid is selected from citric acid.

6. Process for making an aqueous solution according to any of the preceding claims, com- prising in the range of from 40 to 70 % by weight of a complexing agent, selected from the alkali metal salts of aminocarboxylate complexing agents.

7. Process for making an aqueous solution according to any of the preceding claims, com- prising in the range of from 0.1 to 30 % by weight of citric acid.

8. Process for making an aqueous solution according to any of the preceding claims, wherein (i) an inorganic and/or organic acid (B) is added to an aqueous solution of com- plexing agent (A) and subsequently water is removed, or (ii) an aqueous solution of complexing agent (A) and inorganic and/or organic acid (B) is provided, and subsequently further complexing agent (A) is added.

9. Aqueous solution, obtainable or obtained by the process according to any of the preced- ing claims.

10. Use of aqueous solutions according to claim 9 for transportation in a pipe or a container.

11. Use of aqueous solutions according to claim 9 for cleaning agents, preferably selected from hard surface cleaning agents, dishwashing and laundry detergents, the cleaning agent optionally further comprising an antimicrobial agent selected from the group consist- ing of 2-phenoxyethanol; preferably comprising said antimicrobial agent in an amount ranging from 2 ppm to 5% by weight of the composition; more preferably comprising 0.1 to 2% of phenoxyethanol.

12. Process for making a granule or powder of a complexing agent (A), from an aqueous solu- tion according to claim 9 or from an aqueous solution obtainable or obtained by a process according to any of the preceding claims 1 to 8, said process comprising the steps of (a) providing an aqueous solution according to claim 9 or an aqueous solution obtaina- ble or obtained by a process according to any of the preceding claims 1 to 8, and (b) optionally adding additional inorganic or organic acid, and/or (c) optionally adding additional amino carboxylate to form a higher concentrated solu- tion or slurry; and/or (d) optionally adding at least one homo- or copolymer of (meth)acrylic acid, partially or fully neutralized with alkali, (e) optionally heating said solution or slurry to a temperature in the range of from 50 to 90°C, and (f) removing most of the water by an evaporation method selected from spray granula- tion and spray drying, preferably to a residual moisture content of 0.1 to 20 wt%.

13. Process according to claim 12 wherein steps (d) and/or (e) are performed in a fluidized bed or in an essentially horizontal cylindrical drying apparatus containing a stirring ele- ment that rotates around an essentially horizontal axis.

14. Powder or granule of a complexing agent (A), obtainable or obtained by a process accord- ing to any of claims 12 or 13.

15. Use of a powder or granule according to claim 14 for the manufacture of cleaning agents, preferably selected from dishwashing and laundry detergents, more preferably dishwash- ing detergents, particularly automatic dishwashing detergents.

16. Aqueous solution, preferably with a total dry content of at least 45%, comprising (A) in the range of from 30 to 75 % by weight of alkali metal salts of methylglycine di- acetic acid , and (B) in the range of from 0.1 to 40 % by weight of organic acid or inorganic acid, in acidic form, partially deprotonated form, or fully deprotonated form, preferably citric acid, percentages referring to the total respective aqueous solution, preferably having a pH value in the range of from 1 to 13, preferably 4 to 11.