The present invention relates to a process for treating stains on fabric.

EP 0458397 discloses the use of manganese 1, 4, 7-Trimethyl- 1 , 4 , 7-triazacyclononane (Me ₃ -TACN) complexes as bleaching and oxidation catalysts and use for paper/pulp bleaching and textile bleaching processes. 1, 4, 7-Trimethyl-l, 4, 7- triazacyclononane (Me ₃ -TACN) has been used in dishwashing for automatic dishwashers, SUN™, and has also been used in a laundry detergent composition, OMO Power™.

United States Application 2001/0025695A1, Patt et al, discloses the use of PF ₆ ^~ salts of 1, 2, -bis- (4, 7, -dimethyl- 1, 4, 7, -triazacyclonon-1-yl) -ethane and Me ₃ -TACN (Me4-DTNE) .

United States Application 2002/010120 discloses the bleaching of substrates in an aqueous medium, the aqueous medium comprising a transition metal catalyst and hydrogen peroxide .

WO 2006/125517 discloses a method of catalytically treating a cellulose or starch substrate with a Mn(III) or Mn(IV) preformed transition metal catalyst salt and hydrogen peroxide in an aqueous solution. The preformed transition metal catalyst salt is described as having a non- coordinating counter ion and having a water solubility of at least 30 g/1 at 20 ⁰ C. Exemplified ligands of the catalysts described in WO 2006/125517 are 1, 4, 7-Trimethyl-l, 4, 7- triazacyclononane (Mθ ₃ -TACN) and 1, 2, -bis- (4, 7, -dimethyl- 1,4,7, -triazacyclonon-1-yl) -ethane (Me ₄ -DTNE) .

An objective of the invention is to provide an improved stain pretreatment process which uses less chemicals, water etc. without sacrificing cleaning efficiency, especially for white fabrics and light coloured fabrics, relied upon by the modern consumer.

In one aspect the present invention provides a method of bleaching a fabric comprising the following steps: (i) a pretreatment step in which the fabric is treated with an the aqueous solution having a initial pH from 10.5 to 11.5 and comprising 0.5-50 mM (millimol/litre) hydrogen peroxide; followed by

(ii) treatment with a preformed transition metal catalyst, the transition metal catalyst present in a concentration from 0.1 to 100 micromolar of an aqueous solution wherein the initial pH of this second step is from 7-10.

Preferably the initial pH of the pretreatment step is 10.7-11.3 and more preferably 8-9.7.

Preferably the initial pH of the second step is 10.9-11.1 and more preferably 8.5-9.5.

The arrangement of the invention affords judicious use of a bleaching catalyst for effective cleaning of stains without the need for buffers, builders, chorine-based bleaching agents. The method is particularly applicable to laundering machines that have capabilities to control the pH during the washing processes. The method is most particularly applicable to the bleaching of stains found on white garments or light coloured garments.

The preformed transition metal catalyst may be Fe (II) or Fe (III) or Mn (II) or Mn (III) or Mn(IV) . Preferred are Mn (III) or Mn (IV) .

The preformed transition metal catalyst salt may be a mononuclear Mn complex, or a dinuclear Mn(III) or Mn(IV) complex with at least one O ^2~ bridge.

The ligand of the catalyst may be a tridentate, tetradentate, pentadentate or hexadentate nitrogen and oxygen donor.

The manganese transition metal catalyst used may be non- deliquescent by using counter ions such as hexafluorophosphate, acetate, chloride, sulphate, nitrate, being most preferred.

The preformed transition metal catalyst may be a mononuclear or dinuclear complex of a Mn H-V transition metal catalyst, the ligand of the transition metal catalyst of formula (I) :

R N [ CR ₁ R ₉ CR^R, wherein : Q = ^{λ 2 3 4} ; p i s 3 or 4 ;

R is selected from: hydrogen, Cl-C6-alkyl, C2OH, ClCOOH, benzyl, and pyridin-2-ylmethyl or one of R is linked to the N of another Q via an ethylene bridge; Rl, R2, R3, and R4 are selected from: H, Cl-C4-alkyl, and Cl-C4-alkylhydroxy.

R may be selected from: hydrogen, CH3, C2H5, CH2CH2OH, benzyl and CH2COOH. R, Rl, R2, R3, and R4 may be selected from: H and Me.

The catalyst may be derived from a ligand selected from the group consisting 1, 4, 7-Trimethyl-l, 4, 7- triazacyclononane (Me3-TACN) , 1, 2, -bis- (4, 7, -dimethyl- 1, 4, 7, -triazacyclonon-1-yl) -ethane (Me4-DTNE) , 5,12- dimethyl-1, 5, 8, 12-tetraazabicyclo [6.6.2] hexadecane, 5, 12-dibenzyl-l, 5, 8, 12-tetraaza- bicyclo [ 6.6.2 ] hexadecane, .

The preformed catalyst may be an iron complex of a tetradentate, pentadentate or hexadentate nitrogen donor ligand, wherein the ligand is selected from the group consisting of:

wherein each R is selected from: hydrogen, F, Cl, Br, hydroxyl, Cl-C4-alkylO-, -NH-CO-H, -NH-CO-Cl-C4-alkyl,

-NH2, -NH-Cl-C4-alkyl, and Cl-C4-alkyl;

Rl and R2 are selected from Cl-C24-alkyl, C6-C10- aryl, and, a group containing a heteroatom capable of coordinating to a transition metal;

R3 and R4 are selected from hydrogen, C1-C8 alkyl, Cl-

C8-alkyl-O-Cl-C8-alkyl, Cl-C8-alkyl-O-C6-C10-aryl, C6-

C10-aryl, Cl-C8-hydroxyalkyl, and - (CH2) _n C (O) OR5 wherein R5 is selected from: hydrogen, Cl-C4-alkyl, n is from 0 to 4, and mixtures thereof; and,

X is selected from C=O, -[C(R6)2]y~ wherein Y is from 0 to 3 each R6 is selected from hydrogen, hydroxyl, Cl-

C4-alkoxy and Cl-C4-alkyl;

wherein each R ¹ R ² represents -R ⁴ -R ⁵ ,

R represents hydrogen, optionally substituted alkyl, aryl or arylalkyl, or -R ⁴ -R ⁵ , each R ⁴ represents a single bond or optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene, alkylene ether, carboxylic ester or carboxylic amide, and each R ⁵ represents an optionally N-substituted aminoalkyl group or an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl;

R20 _(IV) wherein each R20 is selected from: an alkyl, cycloalkyl, heterocycloalkyl, heteroaryl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, alkylamine and N ⁺ (R21) ₃ , wherein R21 is selected from hydrogen, alkanyl, alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl, aminoalkenyl, alkanyl ether, alkenyl ether, and -CY ₂ -

R22, in which Y is selected from H, CH3, C2H5, C3H7 and R22 is selected from an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; and wherein at least one of R20 is a -CY ₂ -R22; R17R17N-X-NR17R17 (V) , wherein :

X is selected from -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ C(OH)HCH ₂ -; and, R17 represents a group selected from: R17 and alkyl, cycloalkyl, heterocycloalkyl, heteroaryl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, alkylamine and N ⁺ (R19)3 , wherein R19 is selected from hydrogen, alkanyl, alkenyl, arylalkanyl, arylalkenyl, oxyalkanyl, oxyalkenyl, aminoalkanyl, aminoalkenyl, alkanyl ether, alkenyl ether, and -CY ₂ - R18, in which Y is selected from H, CH3, C2H5, C3H7 and R18 is selected from an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; and wherein at least two of R17 are -CY ₂ -R18.

In Formula (II), the heteroatom capable of coordinating to a transition metal may be pyridin-2-yl optionally substituted by -C0-C4-alkyl . The heteroatom donor group may be unsubstituted pyridinyl. X may be C=O or C (OH) 2.

R3 may be equal to R4 and be selected from -C(O)-O-CH3, -C (0) -O-CH2CH3, -C (0) -O-CH2C6H5 and CH2OH.

At least one Rl or R2 (of formula II) is pyridin-2- ylmethyl and the other may be selected from -CH3, -

C2H5, -C3H7, -C4H9, C6H13, C8H17, C12H25, and C18H37. In formula (II) the heteroatom capable of coordinating to a transition metal may be amino optionally substituted by -C0-C4-alkyl . The amino group may be substituted by two Cl-C4-alkyl groups. X may be C=O or C (OH) 2 and R3 = R4 may be selected from -C(0)-0-CH3, - C (0) -O-CH2CH3, -C (0) -O-CH2C6H5 and CH20H. At least one of Rl or R2 may be dimethylamino and the other is selected from -CH3, -C2H5, -C3H7, -C4H9, C6H13, C8H17, C12H25, and C18H37. The heteroatom may be di C1-C4- alkyl amino.

The ligand of formula III may be selected from 1,4,7, 10-tetrakis (pyridine-2ylmethyl) -1,4,7, 10- tetraazacyclododecane, N,N-bis (pyridin-2-yl-methyl) - bis (pyridin-2-yl) methylamine, N, N-bis (pyridin-2-yl- methyl-1, 1-bis (pyridin-2-yl) - 1- aminoethane, N, N, N' , N' -tetra (pyridin-2-yl-methyl) ethylenediamine, N- methyl-tris ( pyridin-2-ylmethyl) ethylene-1, 2-diamine; N-butyl-N, N ' , N ' -tris (pyridin-2-ylmethyl) ethylene-1 , 2- diamine; N-octyl-N, N ' , N ' -tris (pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-dodecyl-N, N ' , N ' - tris (pyridin-2-ylmethyl) ethylene-1, 2-diamine; N- octadecyl-N, N ' , N ' -tris (pyridin-2-ylmethyl) ethylene-1, 2- diamine; N-methyl-N, N ' , N ' -tris (3-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-ethyl-N, N ' , N ' -tris (3- methyl-pyridin-2-ylmethyl) ethylene-1, 2-diamine; N- methyl-N, N ' , N ' -tris (5-methyl-pyridin-2- ylmethyl) ethylene-1 , 2 -diamine; N-ethyl-N, N',N'-tris(5- methyl-pyridin-2-ylmethyl) ethylene-1, 2-diamine; N- benzyl- N, N ' , N ' -tris (3-methyl-pyridin-2- ylmethyl) ethylene-1, 2-diamine; N-benzyl-N, N',N'-tris(5- methyl-pyridin-2-ylmethyl) ethylene-1, 2-diamine; N- methyl-N,N' ,N' -tris (imidazol-2ylmethyl) - ethylenediamine; N-ethyl-N,N' ,N' -tris (imidazol- 2ylmethyl) -ethylenediamine; N, N' -dimethyl-N, N' - bis (imidazol-2-ylmethyl) -ethylenediamine; N-(l-propan- 2-ol) -N, N' ,N' -tris (imidazol-2ylmethyl) -ethylenediamine; N- (l-propan-2-ol) -N, N' ,N' -tris (1-methyl-imidazol- 2ylmethyl) -ethylenediamine; N, N-diethyl-N' , N",N"- tris (5-methyl-imidazol-4ylmethyl) -diethylenetriamine; N- (3-propan-l-ol) -N, N' ,N' -tris (l-methyl-imidazol-2- ylmethyl) -ethylenediamine; N-hexyl-N,N' , N' - tris (imidazol-2ylmethyl) -ethylenediamine; N-methyl- N, N' ,N' -tris (benzimidazol-2ylmethyl) -ethylenediamine; and, N- (3-propan-l-ol) methyl-N, N' , N' -tris (benzimidazol- 2ylmethyl) -ethylenediamine; 1, 4-bis (quinolin-2- ylmethyl) -7-octyl-l, 4, 7-triazacyclononane; 1, 4- bis (quinolin-2-ylmethyl) -7-ethyl-l, 4, 7- triazacyclononane; 1, 4-bis (quinolin-2-ylmethyl) -7- methyl-1, 4, 7-triazacyclononane; 1, 4-bis (pyridyl-2- methyl) -7-octyl-l, 4, 7-triazacyclononane; 1,4- bis (pyridyl-2-methyl) -7-ethyl-l, 4, 7-triazacyclononane; 1, 4-bis (pyridyl-2-methyl) -7-methyl-l, 4, 7- triazacyclononane; 1, 4-bis (pyrazol-1-ylmethyl) -7-octyl- 1,4, 7-triazacyclononane; 1, 4-bis (pyrazol-1-ylmethyl) -7- ethyl-1, 4, 7-triazacyclononane; 1, 4-bis (pyrazol-1- ylmethyl) -7-methyl-l, 4, 7-triazacyclononane, 3, 5- dimethylpyrazol-1-ylmethyl) -7-octyl-l, 4, 7- triazacyclononane; 3, 5-dimethylpyrazol-l-ylmethyl) -7- ethyl-1, 4, 7-triazacyclononane; 3, 5-dimethylpyrazol-l- ylmethyl) -7-methyl-l , 4 , 7-triazacyclononane; 1, 4-bis (1- methylimidazol-2-ylmethyl) -7-octyl-l, 4, 7- triazacyclononane; 1, 4-bis ( 1 -methylimidazol-2- ylmethyl) -7-ethyl-l, 4, 7-triazacyclononane; 1, 4-bis (1- methylimidazol-2-ylmethyl) -7-methyl-l, 4, 7- triazacyclononane, 1,4, 7-tris (quinolin-2-ylmethyl) - 1 , 4 , 7-triazacyclononane; 1, 4, 7-tris (pyridin-2- ylmethyl) -1,4, 7-triazacyclononane .

Other suitable catalysts include, mononuclear manganese complexes with optionally substituted terpyridine complexes, for examples as disclosed in US20040142843, a mononuclear manganese (III) complex with tris (2- (salicylideneamino) ethyl) amine .

The aqueous solution is preferably not buffered. In this regard, the aqueous solution may be substantially free from an inorganic buffer, e.g., carbonate, phosphate, and borate. Most preferably, the aqueous solution is not buffered other than by the organic sequestrant and hydrogen peroxide. The organic sequestrant and hydrogen peroxide may be considered to have some buffering capacity but this is not to be considered as buffering within the context of unbuffered embodiments of the present invention.

If a buffer is present, it is most preferably a carbonate buffer .

Preferably, the aqueous solution comprises from 0.01 to 10 g/1 of an organic sequestrant, the sequestrent selected from: an aminophosphonate sequestrant and a carboxylate sequestrant . The sequestrant is either an aminophosphonate sequestrant or a carboxylate sequestrant. Preferably, the sequestrant is either an aminophosphonate sequestrant or an aminocarboxylate sequestrant.

The following are preferred examples of aminophosphonate sequestrants nitrilo trimethylene phosphonates, ethylene- diamine-N, N, N' , N' -tetra (methylene phosphonates) (Dequest 204) and diethylene-triamine-N, N, N' , N", N"- penta (methylenephosphonates) (Dequest 206), most preferably diethylene-triamine-N, N, N' , N",N"- penta (methylenephosphonates) . One skilled in the art will be aware that that different types of each Dequest exist, e.g., as phosphonic acid or as sodium salts or any mixture thereof.

The following are preferred examples of aminocarboxylate sequestrants: ethylenediaminetetraacetic acid (EDTA), N- hydroxyethylenediaminetetraacetic acid (HEDTA) , nitrilotriacetic acid (NTA) , N-hydroxyethylaminodiacetic acid, N-hydroxyethylaminodiacetic acid, glutamic diacetic acid, sodium iminodisuccinate, diethylenetriaminepentaacetic acid (DTPA), ethylenediamine-N, N' -disuccinic acid (EDDS), methylglycinediacetic acid (MGDA), and alanine-N, N-diacetic acid. A most preferred aminocarboxylate sequestrant is diethylenetriaminepentaacetic acid (DTPA) .

The sequestrants may also be in the form of their salts, e.g., alkali metal, alkaline earth metal, ammonium, or substituted ammonium salts salts. Preferably the sequestrant is in the free acid form, sodium or magnesium salt .

Examples of carboxylate sequestrants are polycarboxylates containing two carboxy groups include the water-soluble salts of succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric acid, as well as the ether carboxylates . Polycarboxylates containing three carboxy groups include, in particular, water-soluble citrates, aconitrates and citraconates as well as succinate derivatives such as the carboxymethyloxysuccinates . Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1,261,829, 1, 1, 2, 2 -ethane tetracarboxylates, 1, 1, 3, 3-propane tetracarboxylates and 1, 1, 2, 3-propane tetracarboxylates. Polycarboxylates containing sulfo substituents include the sulfosuccinate derivatives disclosed in British Patent Nos. 1,398,421 and 1,398,422 and in U.S. Patent No. 3,936,448, and the sulfonated pyrolysed citrates described in British Patent No. 1, 439, 000.

Polycarboxylates containing four carboxy groups include oxydisuccinates disclosed in British Patent No. 1,261,829, 1, 1, 2, 2-ethane tetracarboxylates, 1, 1, 3, 3-propane tetracarboxylates and 1, 1, 2, 3-propane tetracarboxylates.

Other suitable water soluble organic salts are the homo- or co-polymeric polycarboxylic acids or their salts in which the polycarboxylic acid comprises at least two carboxyl radicals separated from each other by not more than two carbon atoms. Polymers of the latter type are disclosed in GB-A-I, 596, 756. Examples of such salts are polyacrylates of M. Wt. 2000 to 5000 and their copolymers with maleic anhydride, such copolymers having a molecular weight of from 20,000 to 70,000, especially about 40,000.

Also copolymeric polycarboxylate polymers which, formally at least, are formed from an unsaturated polycarboxylic acid such as maleic acid, citraconic acid, itaconic acid and mesaconic acid as first monomer, and an unsaturated monocarboxylic acid such as acrylic acid or an alpha -C1-C4 alkyl acrylic acid as second monomer. Such polymers are available from BASF under the trade name Sokalan® CP5 (neutralised form), Sokalan® CP7, and Sokalan® CP45 (acidic form) .

Most preferred sequestrants are Dequest 2066 or Dequest 2047.

A bleach precursor may be used: Peracid may be added to a detergent product, but it is preferably formed in-situ from peroxide and a bleach precursor. A peracid may be formed by perhydrolysis of an acidic bleach precursor by the following reaction :

O O

Il -OOH II R—C—X ►R—C-OOH +X ^"

Different types of precursors, such as e.g. cationic nitriles, have different reaction equations, but are also included in the scope of the present invention. The detergent composition used in the method of the present invention may include one or more bleach precursors.

The most preferred are precursors selected form the group consisting of: sodium nonanoyloxybenzene sulphonate (SNOBS); nonanoyloxy aminocaproyloxy benzene sulphonate (NACOBS) ; sodium-4-benzoyloxy benzene sulphonate (SBOBS); N, N, N ¹ N'- tetraacetyl ethylene diamine (TAED) ; sodium-l-methyl-2- benzoyloxy benzene-4-sulphonate; sodium-4-methyl-3-benzoloxy benzoate; 2- (N, N, N-trimethyl ammonium) ethyl sodium-4- sulphophenyl carbonate chloride (SPCC); trimethyl ammonium toluyloxy-benzene sulphonate; sodium 3, 5, 5-trimethyl hexanoyl-oxybenzene sulphonate (STHOBS) ; and substituted cationic nitriles; and mixtures thereof.

Further peracid bleach precursors are known and amply described in literature, such as in the GB-A-O, 836, 988 ; GB- A-O, 864, 798; GB-A-O, 907, 356; GB-A-I, 003, 310 and GB-A- 1,519,351; DE-A-3, 337, 921 ; EP-A-O, 185,522; EP-A-O , 174 , 132 ; EP-A-O, 120, 591; and US-A-I , 246, 339; US-A-3,332, 882; US-A- 4,128,494; US-A-4, 412, 934 and US-A-4, 675, 393; and cationic i.e. quaternary ammonium substituted peroxyacid precursors are disclosed in US-A-4, 751,015 and US-A-4, 397, 757, in EP- A-O, 284, 292 and EP-A-O, 331, 229.

The peracid forming reaction of peroxide and bleach precursor from the detergent may be obtained in the washing liquor inside the washing machine drum, or in an off-line mixing vessel. An advantage of the latter is that the peracid may be formed in a concentrated form at the desired pH and may be diluted with acidic water into the washing machine drum, thereby reducing the pH for the washing process resulting in better bleaching activity.

The low environmental impact detergent product which can be used with the present invention preferably comprises bleach precursor in a peroxide: precursor ratio of between 1:2 and 25:1, more preferably between 2:1 and 10:1 on a molar basis.

Preferably the process is carried out in an automatic washing machine. A peroxide generating cell comprising an electrochemical cell for the production of peroxide from tap water and air, and being suitable for use in said machine when the machine is in operation; whereby no added chemicals are needed to product hydrogen peroxide when the device is in operation.

The hydrogen peroxide is preferably only added in the first step but may be present in the second step provided the initial pH levels are as defined above.

The peroxide generating cell is preferably an electrochemical cell comprising one or more cathode and anode electrodes that are chargeable by a DC potential. The electrodes may for instance be in the form of plates or rods, preferably plates. The cathode is preferably a gas diffusion electrode. The cathode preferably comprises a catalyst bound to the cathode surface. The cathode may comprise conductive materials such as carbon (e.g. graphite, carbon nano-tubes and other forms of carbon) , metals or conductive polymers or combinations thereof. Preferred metal catalysts are transition metals, transition metal oxides or transition metal macrocycles. Preferred transition metals include gold, mercury and oxide covered metals such as nickel and cobalt. Preferred metal oxides include nickel oxide, cobalt oxide and spinels. Preferred transition metal macrocycles include: CoTsPc (phthalocyanine tetra- sulfonate) cobalt) and CoTMPP (tetramethoxyphenyl porphyrine) . The Anode is preferably a dimensionally stable anode, which is preferably constructed from conductive materials such as metals, carbon or conductive polymers or combinations thereof.

Some transition metals are not preferred, in particular platinum, platinum alloys, platinum family metals, palladium, and silver. Also not preferred are perovskites and pyrochlores, such as lead ruthenate transition metal oxides, and macrocyclic FeTsPc (iron tetrasulfonato phthalocyanine) .

The dimensions and specification of the peroxide generating cell are dependent on the intended use. If the peroxide is stored in a buffer tank inside the washing machine, a slow system producing peroxide e.g. overnight is suitable. However, when the peroxide is to be produced during the washing process, a fast producing system is required. The peroxide generating cell of the present invention preferably comprises a total cathode area of at least 10 cm ² , more preferably at least 50 cm2, even more preferably at least 100 cm2 and at most 1000 cm ² , more preferably at most 500 cm ² , even more preferably at most 400 cm ² , still more preferably at most 300 cm ² ; the area being dependent on the demanded production rate. The surface area is preferably divided over between 1 and 25, more preferably between 1 and 10 cathode electrodes. The peroxide production rate is typically between 0.1 and 2000 mmol/h. The actual rate is dependent on amongst others the surface area of the cathode and the type of operation. In a system with a peroxide storage tank, a slow production rate is preferred, typically from 0.1 to 200 mmol/hr, while in a system where the peroxide is produced immediately during water intake, the production rate is preferably between 200 and 2000 mmol/hr. The efficiency of this type of peroxide generating cell is preferably from 50 to 100% at or just after the start of the peroxide production, typically from 60 to 95%.

The total surface area of the anodes is between 10 and 100% of the total surface area of the cathodes.

The electrodes are optionally separated by a semi-permeable membrane .

The machine preferably also comprises a pH modifying device comprising an electrochemical cell comprising one or more cathode and anode electrodes for the production of acidic and alkaline water; whereby no added chemicals are needed to modify pH when the device is in operation.

Surfactant

The formulation used may contain a surfactant or a surfactant mixture. The use of surfactants, for example, helps to remove the waxy materials encountered in cotton. The surfactant may comprise one or more anionic, non-ionic, cationic, amphoteric, and zwitterionic surfactant, and - I i

mixtures thereof. Further examples are given in Surface Active Agents and Detergents (VoI I and II by Schwartz, Perry and Berch) . A variety of such surfactants are also generally disclosed in US-A-3, 929, 678.

In this regard, it is preferred that a surfactant is present in the range from 0.1 to 20 g/L, preferably 0.5 to 10 g/1. It is preferred that the surfactant is a non-ionic surfactant and most preferably biodegradable.

Additional detergent ingredients may be used also, such as enzymes. Preferred enzymes include, but are not limited to proteases, cellulases, lipases, amylases, peroxidases. The detergent may contain one or more optional cleaning agents, which include any agent suitable for enhancing the cleaning, appearance, condition and/or garment care. Generally, the optional cleaning agent may be present in the compositions of the invention in an amount of 0 to 20 wt.%, preferably 0.001 wt.% to 10 wt.%, more preferably 0.01 wt.% to 5 wt.% by weight of the total detergent composition.

Some suitable optional cleaning agents include, but are not limited to antibacterial agents, colorants, perfumes, pro- perfumes, finishing aids, lime soap dispersants, composition malodour control agents, odour neutralisers, polymeric dye transfer inhibiting agents, crystal growth inhibitors, anti- tarnishing agents, anti-microbial agents, anti-oxidants, anti-redeposition agents, soil release polymers, thickeners, abrasives, corrosion inhibitors, suds stabilising polymers, process aids, fabric softening agents, optical brighteners, hydrotropes, suds or foam suppressors, suds or foam boosters, anti-static agents, dye fixatives, dye abrasion inhibitors, wrinkle reduction agents, wrinkle resistance agents, soil repellency agents, sunscreen agents, anti-fade agents, and mixtures thereof.

The detergent may be dosed in any suitable format such as a liquid, gel, paste, tablet or sachet. In some cases granular formulations may be used although this is not preferred. In one preferred embodiment the detergent is a non-aqueous product. Non-aqueous for the purpose of the present invention is meant to describe a product comprising less than 10 %, preferably less than 5 %, more preferably less than 3 % by weight of free water. The non-aqueous product may be a liquid, gel or paste or encapsulated in a sachet.

It is desirable to equip washing machines with one or more detergent product containers so that the detergent product may be dosed automatically. The detergent may be dosed from a single container. Alternatively, the ingredients making up the detergent may be dosed from separate containers as described in EP-A-0419036. Thus in one preferred embodiment at least one ingredient from the detergent is dosed automatically. One advantage of a detergent may be that the reduced number and/or amount of ingredients enables a much smaller volume of detergent product. In practice this would mean that the consumer does not need to refill the containers as often or that the containers may be smaller, therefore making an automatic dosage system more feasible when using the device of the invention. When an automatic dosage system is applied, it is preferred that the bleach precursor or activator (catalyst) is stored separately from the other components of the detergent product.

EXAMPLES

Below are non limiting examples of the invention, included by way of example only.

The BC-I stain was obtained by CFT, Vlaardingen, Netherlands.

The grass stain is prepared by rubbing fresh grass into cotton, after which it is brushed to get an evenly distributed stain.

The Bandy Black Clay stain is prepared by rubbing soil mud into cotton, after which it is brushed to get an evenly distributed stain.

Experimental Method:

Demineralised aqueous solution of 10 iπmol/1 hydrogen peroxide was made that contained either no buffer, carbonate buffer (0.3 g/1 Na ₂ CO ₃ ), Na-LAS/Lutensol A03 (each 0.4 g/1) + 0.3 g/1 Na ₂ CO ₃ , Lutensol A07 (0.8 g/1) + 0.3 g/1 Na ₂ CO ₃ . The appropriate amount of NaOH solution was added to either yield pH 10.5 or pH 11.0.

The stains were first pre-treated at high pH using the above pre-treatment formulations, without catalyst for 20 minutes at 4O ⁰ C under mild agitation. The cloth/liquor (w/w) ratio was approximately 40.

After 20 minutes the cloths were removed from the pre- treatment solutions, rinsed twice with demineralised water, dried and added to a fresh solution containing

a. 10 mmol/1 H2O2, 20 μM of catalyst at pH 8, 9. b. 10 mmol/1 H2O2, 20 μM of catalyst at pH 8, 9. c. 10 mmol/1 H2O2, 20 μM of catalyst at pH 8, 9. d. 10 mmol/1 H2O2, 20 μM of catalyst at pH 8, 9.

The cloths were then treated for another 10 minutes at 4O ⁰ C.

Note: Here, the pre-treatment step is done in the same composition (buffer, surfactant) as the 2 ^nd stage process with catalyst) . However, the pH in the 2 ^nd stage different (lower) .

The cloths were then rinsed twice with phosphate buffer, dried and then measured for change in colour was measured with a Linotype-Hell scanner (ex Linotype) . The change in colour (including bleaching) is expressed as the ΔE value versus white and the values in the tables are 100- ΔE; a higher SRI value means a cleaner cloth (100=white) . The measured colour difference (ΔE) between the washed cloth and the unwashed cloth is defined as follows:

ΔE = [ (ΔL) ² + (Δa) ² + (Δb) ² ] ^1/2 wherein ΔL is a measure for the difference in darkness between the washed and unwashed test cloth; Δa and Δb are measures for the difference in redness and yellowness respectively between both cloths. With regard to this colour measurement technique, reference is made to Commission International de 1 'Eclairage (CIE); Recommendation on Uniform Colour Spaces, colour difference equations, psychometric colour terms, supplement no 2 to CIE Publication, no 15, Colormetry, Bureau Central de Ia CIE, Paris 1978. The results are shown below in the tables and are listed.

Comparisons are in all cases made wherein the catalyst has been added at t=0 in the same solution as given above for the 2 ^nd process (so between pH 8 and 10 with different formulations) .

Different stains were used: BC-I (tea-based monitor) , Curry oil, Bandy black clay and grass.

Below the results for different catalysts are given.

1. [Mn ₂ (μ-O) ₃ (Me ₃ tacn) ₂ ] (PF ₆ ) ₂

Mn ₂ ( -O) ₃ ( 1 , 4 , 7 -t rime thy 1- 1 , 4 , 7 -triazacyclononane ) ₂ ] PF ₆ ) 2 was prepared as published elsewhere (J. Chem. Soc, Dalton Trans, 353 (1996) ) .

Effect of pre-treatment process on BC-I stains a. Pretreating the stain at pH 11 with carbonate buffer, and then adding catalyst at pH 9.6, yields 95 SRI. The reference at pH 9.5 gives 92 SRI. b. Pretreating the stain at pH 11 without buffer, and then adding catalyst at pH 7.1, yields 92 SRI. The reference at pH 8 gives 88 SRI. c. Pretreating the stain at pH 11 with Lutensol A07 and carbonate buffer, and then adding catalyst at pH 9.5, yields 95.5 SRI. The reference at pH 9.0 gives 93 SRI.

Effect of pre-treatment process on CBB stains

a. Pretreating the stain at pH 11 with Lutensol A07 and carbonate buffer, and then adding catalyst at pH 10, yields 88 SRI. The reference at pH 9.3 gives 82 SRI. b. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH 10, yields 88 SRI. The reference gives at pH 9.5 84 SRI.

Effect of pre-treatment process on grass stains

a. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH 8.6, yields 77 SRI. The reference at pH 8.5 gives 69 SRI. b. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH 9.1, yields 77 SRI. The reference at pH 9 gives 71 SRI. c. Pretreating the stain at pH 11 with Lutensol A07 in carbonate buffer, and then adding catalyst at pH 8.3, yields 76 SRI. The reference at pH 8.5 gives 68 SRI. d. Pretreating the stain at pH 11 with Lutensol A07 in carbonate buffer, and then adding catalyst at pH 9.9, yields 78 SRI. The reference at pH 9.5 gives 69 SRI.

2. [Mn(Bcyclam)Cl ₂ ]

4, 11 -dimethyl- 1, 4, 8, 11-tetraazabicyclo [6.6.2] hexadecane , hereafter referred to as Bcyclam, and the corresponding manganese (II) complex, [Mn (Bcyclam) CI2] , were prepared as described in WO98/39098 and J.Am. Chem.Soc, 122, 2512 (2000) ) .

Effect of pre-treatment process on grass stains

a. Pretreating the stain at pH 10.5 with Na-LAS/Lutosol

A03 in carbonate buffer, and then adding catalyst at pH 8.2, yields 77 SRI. The reference at pH 8.3 gives 70 SRI. b. Pretreating the stain at pH 10.5 with Lutensol A07 in carbonate buffer, and then adding catalyst at pH 8.2, yields 74.5 SRI. The reference at pH 8.4 gives 68.5 SRI.

3. [Fe(N2py3o)Cl]Cl

Dimethyl 2, 4-di- (2-pyridyl) -3-methyl-7- (pyridin-2-ylmethyl) - 3,7-diaza-bicyclo[3.3.1]nonan-9-one-l,5-dicarboxylate (N2py3o) and the iron (II) complex thereof [Fe (N2py3o) Cl] Cl was prepared as described in WO0248301. Effect of pre-treatment process on grass stains

a. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH 8, yields 78 SRI. The reference at pH 8.5 gives 68 SRI. b. Pretreating the stain at pH 11 with Lutensol A07 in carbonate buffer, and then adding catalyst at pH 8, yields 75 SRI. The reference at pH 8.4 gives 68 SRI.

4. [Fe(N2py2-amine)Cl]Cl

Dimethyl 2, 4-di- (2-pyridyl) -3-methyl-7-

( (dimethylamino) ethyl) -3,7-diaza-bicyclo[3.3.1]nonan-9-one- 1, 5-dicarboxylate (N2py2-amine) and the iron (II) complex thereof [Fe (N2py2-amine) Cl] Cl was prepared as described in WO 03/104379.

Effect of pre-treatment process on grass stains

a. Pretreating the stain at pH 10.5 with Na-LAS/Lutosol

A03 in carbonate buffer, and then adding catalyst at pH 8.1, yields 80 SRI. The reference at pH 8.4 gives 70 SRI. b. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH

9.4, yields 78 SRI. The reference at pH 9.1 gives 71 SRI. c. Pretreating the stain at pH 11 with Lutensol A07 in carbonate buffer, and then adding catalyst at pH 8, yields 77 SRI. The reference at pH 8.2 gives 70 SRI. Effect of pre-treatment process on curry oil stains

a. Pretreating the stain at pH 10.5 in carbonate buffer, and then adding catalyst at pH 7.9, yields 57 SRI. The reference at pH 7.6 gives 47 SRI.

Pretreating the stain at pH 11 without buffer, and then adding catalyst at pH 5.4, yields 63 SRI. The reference at pH 7.5 gives 53 SRI.

5. [Fe(MeN4py)Cl]Cl

N,N-bis (pyridin-2-yl-methyl-l, 1-bis (pyridin-2-yl) - 1- aminoethane , hereafter referred to as MeN4Py, and the corresponding iron (II) complex, [Fe (MeN4py) Cl] Cl, were prepared as described in EP0909809. Note that this catalyst has been used in all experiments at 10 μM level

Effect of pre-treatment process on grass stains

a. Pretreating the stain at pH 10.5 with Na-LAS/Lutosol

A03 in carbonate buffer, and then adding catalyst at pH 8, yields 77 SRI. The reference at pH 8.6 gives 68 SRI. b. Pretreating the stain at pH 11 with Na-LAS/Lutosol A03 in carbonate buffer, and then adding catalyst at pH 9.2, yields 77 SRI. The reference at pH 9.2 gives 69 SRI.

Conclusions

The results are considered to be more than 95% different

(least significant difference) , when a difference in SRI of at least 0.5 for BC-I; 2.8 for curry oil; 1.2 for carbon black clay; and 1.1 for the grass stain was observed. So all results given above show that the effect of pre- treatment without catalyst give a significant benefit compared to the single-stage process.

Comparative example to show Effect of increased pH on bleaching performance of [Mn ₂ (μ-O) 3 (Mβ3tacn) ₂ ] (PF ₆ ) 2

The bleaching step (without pre-treatment) was done in the presence of 5 μM of [Mn ₂ (μ-O) 3 (Me ₃ tacn) ₂ ] (PF ₆ ) ₂ at different pH's at 40 ⁰ C for 30 min on BC-I and the SRI values, as defined above, were as follows:

With Sodium Carbonate buffer (0.3 g/1) , no surfactant pH 8.0: 92.8 pH 10.2 95.5

No buffer, no surfactant pH 5.2 87.5 pH 9.9 94.5

Na-LAS/Lutensol A03 (each 0.4 g/1) + 0.3 g/1 Na ₂ CO ₃ pH 7.8 92.9 pH 9.7 95.6

Lutensol A07 (0.8 g/1) + 0.3 g/1 Na ₂ CO ₃ . pH 8.0 93.6 pH 9.5 95.6 Conclusion

The results show the effect of pre-treatment without catalyst at a higher pH 9-11.5 gives a significant benefit compared to when carried out at low pH.