GB2386616A - Bleaching composition - Google Patents

Abstract

A bleaching composition comprises a ligand, L, which forms a complex with a transition metal, and a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system, said ligand having a hydrophobic substituent and present in the bleaching composition as a free ligand, said hydrophobic substituent increasing hydrophobicity of the transition metal binding moiety of the ligand, wherein the ligand has a Log P value of at least 3, with the proviso that N, N, N', N'-tetra(pyridin-2-yl-methyl)ethylenediamine) is excluded. The composition provides superior bleaching for oily stains.

Description

- 1 ENHANCEMENT OF BLEACHING CATALYSTS

FIELD OF INVENTION

This invention relates to the enhancement of bleaching 5 catalysts in laundry.

BACKGROUND OF INVENTION

The use of bleaching catalysts for stain removal has been developed over recent years. The recent discovery that some lo catalysts are capable of bleaching effectively in the absence of an added peroxyl source has recently become the focus of some interest, for example: W09965905; WO0012667; WO0012808; W00029537, and, W00060045. There are many examples of catalysts for use in bleaching with peroxyl 15 species and substantial overlap between those for bleaching without added peroxyl and with peroxyl species.

Ways of enhancing the activity or improving the stain bleaching profile of these catalysts are desired.

SUMARY OF INVENTION

We have found that a bleaching composition comprising a hydrophobic free ligand of a bleaching catalyst and a peroxygen bleach, preferably together with a hydrophilic 25 sequestrant provides superior bleaching for oily stains.

Without being bound by theory we postulate the following.

The addition of the bleaching composition of the present invention to an aqueous medium containing a substrate 30 carrying an oily stain permits targeting of the oily stain with the hydrophobic free ligand. The hydrophobic free

ligand in the oily stain forms a complex with adventitious transition metals found in the oily stain, the complex together with a peroxyl species serves to bleach the chromophore in the stain. In a preferred feature 5 complexation of the hydrophobic free ligand is reduced in the aqueous medium because of the presence of the sequestrant and adventitious transition metals in the stain are substantially unaffected by the sequestrant because the sequestrant does not partition into the oily stain.

The present invention provides a bleaching composition comprising a ligand, L, which forms a complex with a transition metal, and a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system, said organic substance 15 having a hydrophobic substituent and present in the bleaching composition as a free ligand, said hydrophobic substituent increasing hydrophobicity of the transition metal binding moiety of the organic substance, wherein the organic substance has a Log P value of at least 3, with the 20 proviso that N. N. N', N'-tetra(pyridin-2-yl-

methyl)ethylenediamine) is excluded. It is preferred that the composition comprises sodium percarbonate as a peroxygen bleach, most preferably above 4% wt/wt.

25 One or more substituents bound to the ligand increase the ligands hydrophobicity. Nevertheless is important that the ligand has some Volubility in an aqueous bleaching medium so that it may partition effectively with the oily stain. It is preferred that the ligand has LogP of less than 20.

In addition, for the present invention to function it is believed that the ligand becomes present on the stain and is also competent to form a transition metal complex within a timeframe that is acceptable to consumer bleaching. The 5 aqua complexes of Manganese(II) and Iron(II) metal ions give rise to fast exchange reactions that are in the order of 106 to 107 S-1, see Huheey, Inorganic Chemistry, Principles of structure and reactivity, 2nd Ed, Harper International Edition. Ligands that are kinetically fast in binding to 10 these metals will also give rise to their corresponding complexes rapidly. An example of such a class of ligands which are kinetically favourable to forming transition metal complexes are the trispicen-ligands. Trispicen-ligands are generally of the following form: N R1 1 \NN: N Without being limited to the theory, we postulate that the transition metal ions present in the stain bind in a hydrophobic matrix to the hydrophobic ligand. It is preferred that the ligands as used in the present invention 20 are capable of forming a transition metal catalyst after migration to an oily stain in the wash such that an active species is formed for bleaching with peroxyl species in the wash. 25 There is also an example of a class of ligands that are kinetically incompetent to bind to the metal ions, namely

5,12-dimethyl-1,5,8,12-tetraazabicyclo[.6.2]hexadecane (bicyclam). As discussed in papers from D. Busch and co workers, this class of ligands shows a great rigidity and therefore increases the kinetic stability of the complexes 5 (see Hubin et al, Inorg. Chem., 40, 435, 2001). Also the formation of complexes is very slow, also due to strong protonation features of the ligand. Hydrophobic ligands that are most preferred are those that will migrate from an aqueous wash into the stain and form a transition metal 10 complex from adventitious transition metal complexes present in the stain.

The present invention extends to a method of bleaching a substrate comprising applying to the substrate, in an 15 aqueous medium, the bleaching composition according to the present invention.

The present invention extends to a commercial package comprising the bleaching composition according to the 20 present invention together with instructions for its use.

The bleaching composition may be contacted to the textile fabric in any suitable manner. For example, it may be applied in dry form, such as in powder form, or in a liquor 25 that is then dried, for example as an aqueous spray-on fabric treatment fluid or a wash liquor for laundry cleaning, or a non-aqueous dry cleaning fluid or spray-on aerosol fluid.

- 5 Any suitable textile that is susceptible to bleaching or one that one might wish to subject to bleaching may be used.

Preferably the textile is a laundry fabric or garment.

5 In a preferred embodiment, the method according to the present invention is carried out on a laundry fabric using an aqueous treatment liquor. In particular, the treatment may be effected in a wash cycle for cleaning laundry. More preferably, the treatment is carried out in an aqueous 10 detergent bleach wash liquid.

In a particularly preferred embodiment the method according to the present invention is carried out on a laundry fabric using aqueous treatment liquor. In particular the treatment 15 may be effected in, or as an adjunct to, an essentially conventional wash cycle for cleaning laundry. More preferably, the treatment is carried out in an aqueous detergent wash liquor. The bleaching composition can be delivered into the wash liquor from a powder, granule, 20 pellet, tablet, block, bar or other such solid form. The solid form can comprise a carrier, which can be particulate, sheet-like or comprise a three-dimensional object. The carrier can be dispersible or soluble in the wash liquor or may remain substantially intact. In other embodiments, the 25 bleaching composition can be delivered into the wash liquor from a paste, gel or liquid concentrate.

A unit dose as used herein is a particular amount of the bleaching composition used for a type of wash. The unit 30 dose may be in the form of a defined volume of powder, granules or tablet.

- 6 DETAILED DESCRIPTION OF THE INVENTION

Bleach Catalyst The bleach catalyst is formed in situ and likely forms a 5 complex with transition metal ions contained within an oily stain. The ligand for use in the present invention may be formed by functionalising one of the ligands detailed below as part of the ligand synthesis or may be functionalised after synthesis of the ligand backbone. Some of the ligands 10 detailed below in generic formulas may have the required HLB. The ligand moiety of the bleaching composition may be selected from a wide range of organic molecules (ligands) of 15 the TPEN/trispicen types, which are a pentadentate or hexadentate ligand of the general Formula (I) : R1RlN-W-NRlR2 (I) 20 wherein each R1 independently represents -R3-V, in which R3 represents optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene or alkylene ether, and V represents an optionally substituted heteroaryl group 25 selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; W represents an optionally substituted alkylene bridging group selected from 30 -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, CH2-C6H4-CH2-, -CH2-C6H1o CH2-, and -CH2-CloH6-cH2-i and

R2 represents a group selected from R1, and alkyl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, 5 amine, and alkylamine.

The ligand forms a transition metal complex preferably of the general formula in the oily stain (AI): 10 [MaLkXn] Ym in which: M represents a metal selected from Mn(II)-(III)-(IV) (V), Cu(I)-(II)-(lII), Fe (II)-(II1) -(IV)-(V), Co(I)-(II) 15 ( II), Ti(lI)-(I] I)(IV), V(]I)-( I E)-(IV)-(V), Mo(II) (III)-(IV)-(V)-(V1) and W(IV)-(V)-(VI), preferably from Fe(II)(IIl)-(IV)-(V); L represents a ligand having a LogP of at least 3, preferably a ligand as defined in formula (I); 20 X represents a coordinating species selected from any mono, bi or tri charged anions and any neutral molecules able to coordinate the metal in a mono, bi or tridentate manner; Y represents any non-coordinated counter ion; 25 a represents an integer from 1 to 10; k represents an integer from 1 to 10; n represents zero or an integer from 1 to 10; m represents zero or an integer from 1 to 20.

- 8 Log P values Log P is the n-octanol/water partition coefficient that can be used to relate chemical structure to observed chemical behavior. Log P is related to the hydrophobic character of 5 the molecule.

The Log P values were calculated within Cerius2, using QSAR+, which is a program obtained from Accelrys Inc., 9685 Scranton Road, San Diego, CA 92121. The QSAR+ descriptor 10 ALogP and molar refractivity are calculated using the method described by Chose & Crippen (1989). In this atom-based approach, each atom of the molecule is assigned to a particular class, with additive contributions to the total value of loop and molar refractivity. For more information 15 about this descriptor the reader is directed to Leffler and Grunwald (1963).

Below are given are Log P values for a series of ligands.

R1 \NN: IN

- 9 Log P R1 = methyl 2.40 R1 = e-ethyl 2.75 R1 = pyridin-2-ylmethyl 3.05 R1 = n-propyl 3.28 R1 = n-Bu 3.73 R1 = CH2C6H5 3.99

R1 = n-hexyl 4.64 R1 = n-C18H37 10.12 No NN Log P = 3.86 5 Log P = 4.21 Log P = 3.32

NN: J IN Log P = 3. 86 NN it' Log P = 5.23 :, >I Log P = 3.57 \ N,N Log P = 0.50 l INN: N I OWN\ Log P = 0. 4 2

Sequestrant It is preferred that the bleaching composition comprises a transition metal sequestrant at a level of from 0.005% to 20%, preferably from 0.1% to 10%, more preferably from 0.25% 5 to 7.5% and most preferably from 0.5% to 5% by weight of bleaching composition.

The bleaching composition preferably contains a transition metal sequestrant. These components may also have calcium 10 and magnesium chelation capacity, but preferentially they show selectivity to binding transition metal ions such as iron, manganese and copper.

Suitable transition metal ion sequestrants for use herein 15 include organic phosphonates, such as the amino alkylene poly (alkylene phosphonates), alkali metal ethane 1-hydroxy disphosphonates and nitrilo trimethylene phosphonates.

Preferred among the above species are diethylene triamine 20 penta (methylene phosphonate), ethylene diamine tri (methylene phosphonate) hexamethylene diamine tetra (methylene phosphonate) and hydroxy-ethylene 1,1 diphosphonate. 25 Other suitable transition metal ion sequestrant for use herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, ethylenediamine disuccinic acid, ethylenediamine diglutaric acid, 30 2hydroxypropylenediamine disuccinic acid or any salts thereof.

Especially preferred is ethylenediamine-N,N'-disuccinic acid (EDDS) or the alkali metal, alkaline earth metal, ammonium, or substituted ammonium salts thereof, or mixtures thereof.

5 Other suitable transition metal ion sequestrants for use herein are iminodiacetic acid derivatives such as 2-hydroxyethyl diabetic acid or glyceryl imino diabetic acid, described in EP-A-317,542 and EP-A-399,133. The iminodiacetic acid-N-2-hydroxypropyl sulphonic acid and 10 aspartic acid N-carboxymethyl N-2-hydroxypropyl-3-sulphonic acid sequestrants described in EP-A-516,102 are also suitable herein. The g-alanine-N,N'diacetic acid, aspartic acid-N,N'-diacetic acid, aspartic acid-Nmoncacetic acid and iminodisuccinic acid sequestrants described in EP-A509,382 15 are also suitable.

EP-A476,257 describes suitable amino based sequestrants.

EP-A-510,331 describes suitable sequestrants derived from collagen, keratin or casein. EP-A-528,859 describes a 20 suitable alkyl iminodiacetic acid sequestrant. Dipicolinic acid and 2-phosphonobutane-1, 2,4-tricarboxylic acid are also suitable.

Glycinamide-N,N'-disuccinic acid (GADS), ethylenediamine-N 25 N'diglutaric acid (EDDG) and 2-hydroxypropylenediamine-N-

N'-disuccinic acid (HPDDS) are also suitable.

Builders The bleaching composition may contain as builder a 30 crystalline aluminosilicate, preferably an alkali metal

- 13 aluminosilicate, more preferably a sodium aluminosilicate (zeolite). The zeolite used as a builder may be the commercially 5 available zeolite A (zeolite 4A) now widely used in laundry detergent powders. Alternatively, the zeolite may be maximum aluminium zeolite P (zeolite MAP) as described and claimed in EP 384 070B (Unilever), and commercially available as Doucil (Trade Mark) A24 from Crosfield

10 Chemicals Ltd. UK.

Zeolite MAP is defined as an alkali metal aluminosilicate of zeolite P type having a silicon to aluminium ratio not exceeding 1.33, preferably within the range of from 0.90 to 15 1.33, preferably within the range of from 0.90 to 1.20.

Especially preferred is zeolite MAP having a silicon to aluminium ratio not exceeding 1.07, more preferably about 1.00. The particle size of the zeolite is not critical.

20 Zeolite A or zeolite MAP of any suitable particle size may be used.

Also preferred according to the present invention are phosphate builders, especially sodium tripolyphosphate.

25 This may be used in combination with sodium orthophosphate, and/or sodium pyrophosphate.

Other inorganic builders that may be present additionally or alternatively include sodium carbonate, layered silicate, 30 amorphous aluminosilicates.

Most preferably, the builder is selected from sodium tripolyphosphate, zeollte, sodium carbonate, and combinations thereof.

5 Organic builders may optionally be present. These include polycarboxylate polymers such as polyacrylates and acrylic/maleic copolymers; polyaspartates; monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, glycerol mono-di- and trisuccinates, 10 carboxymethyloxysuccinates, carboxy-methyloxymalonates, diplcolinates, hydroxyethyl iminodiacetates, alkyl- and alkenylmalonates and succinates; and sulphonated fatty acid salts. 15 Organic builders may be used in minor amounts as supplements to inorganic builders such as phosphates and zeolites.

Especially preferred supplementary organic builders are citrates, suitably used in amounts of from 5 to 30 wt%, preferably from 10 to 25 wt%, and acrylic polymers, more 20 especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 wt%, preferably from 1 to 10 wt%.

Builders, both inorganic and organic, are preferably present 25 in alkali metal salt, especially sodium salt, form.

Peroxygen Bleach or Source Thereof In a peroxyl bleaching mode the composition of the present invention uses a peroxyl species to bleach a substrate. The peroxy bleaching species may be a compound which is capable of yielding hydrogen peroxide in aqueous solution. Hydrogen

- 15 peroxide sources are well known in the art. They include the alkali metal peroxides, organic peroxides such as urea peroxide, and inorganic persalts, such as the alkali metal perborates, percarbonates, perphosphates persilicates and 5 persulphates. Mixtures of two or more such compounds may also be suitable.

Particularly preferred are sodium perborate tetrahydrate and, especially, sodium perforate monohydrate. Sodium 10 perborate monohydrate is preferred because of its high active oxygen content. Sodium percarbonate may also be preferred for environmental reasons. The amount thereof in the composition of the invention usually will be within the range of about 1-35% by weight, preferably from 5-25% by 15 weight. One skilled in the art will appreciate that these amounts may be reduced in the presence of a bleach precursor e.g., N,N,N'N'-tetraacetyl ethylene diamine (TAED).

Another suitable hydrogen peroxide generating system is a 20 combination of a C1-C4 alkanol oxidase and a C1-C4 alkanol, especially a combination of methanol oxidase (MOX) and ethanol. Such combinations are disclosed in International Application PCT/EP 94/03003 (Unilever), which is incorporated herein by reference.

Alkylhydroxy peroxides are another class of peroxy bleaching compounds. Examples of these materials include cumene hydroperoxide and t-butyl hydroperoxide.

- 16 Organic peroxyacids may also be suitable as the peroxy bleaching compound. Such materials normally have the general formula: o H / \O / C \ /

wherein R is an alkylene or substituted alkylene group containing from 1 to about 20 carbon atoms, optionally having an internal amide linkage; or a phenylene or substituted phenylene group; and Y is hydrogen, halogen, 10 alkyl, aryl, an imido-aromatic or non-aromatic group, a COON or / \ / 11 0 o group or a quaternary ammonium group.

Typical monoperoxy acids useful herein include, for example: (i) peroxybenzoic acid and ring-substituted peroxybenzoic acids, e.g. peroxy-. alpha.-naphthoic acid; (ii) aliphatic, substituted aliphatic and arylalkyl monoperoxyacids, e.g. peroxylauric acid, peroxystearic acid and N,N-phthaloylaminoperoxy caproic acid (PAP); and 25 (iii) 6-octylamino-6oxo-peroxyhexanoic acid.

Typical diperoxyacids useful herein include, for example:

- 17 (iv) 1,12-diperoxydodecanedioic acid (DPDA); (v) 1,9-diperoxyazelaic acid; (vi) diperoxybrassilic acid; diperoxysebasic acid and diperoxyisophthalic acid; (vii) 2-decyldiperoxybutane-1,4-diotic acid; and (viii) 4,4'-sulphonylbisperoxybenzoic acid.

Also inorganic peroxyacid compounds are suitable, such as for example potassium monopersulphate (MPS). If organic or 15 inorganic peroxyacids are used as the peroxygen compound, the amount thereof will normally be within the range of about 2-10% by weight, preferably from 4-8% by weight.

Peroxyacid bleach precursors are known and amply described 20 in literature, such as in the British Patents 836988; 864,798; 907,356; 1, 003,310 and 1,519,351; German Patent 3,337,921; EP-A-0185522; EP-A0174132; EP-A-0120591; and U.S. Pat. Nos. 1,246,339; 3,332,882; 4,128,494; 4,412,934 and 4,675,393.

Another useful class of peroxyacid bleach precursors is that of the cationic i.e. quaternary ammonium substituted peroxyacid precursors as disclosed in US Pat. Nos. 4,751,015 and 4,397,757, in EP-A0284292 and EPA-331,229. Examples of 30 peroxyacid bleach precursors of this class are:

- 18 2-(N,N,N-trimethyl ammonium) ethyl sodium-4-sulphonphenyl carbonate chloride (SPCC); N-ocLyl-N,N-dimethyl-N10-carbophenoxy decyl ammonium 5 chloride (ODC); 3-(N,N,N-trimethyl ammonium) propyl sodium-4-sulphophenyl carboxylate; and 10,N,N-trimethyl ammonium toluylexy benzene sulphonate.

A further special class of bleach precursors is formed by the cationic nitrides as disclosed in EP-A-303,520 and in European Patent Specification No.'s 458,396 and 464,880.

Any one of these peroxyacid bleach precursors can be used in the present invention, though some may be more preferred than others.

20 Of the above classes of bleach precursors, the preferred classes are the esters, including acyl phenol sulphonates and acyl alkyl phenol sulphonates; the acyl-amides; and the quaternary ammonium substituted peroxyacid precursors including the cationic nitrites.

Examples of said preferred peroxyacid bleach precursors or activators are sodium-4-benzoyloxy benzene sulphonate (SBOBS); N,N,N'N'-tetraacetyl ethylene diamine (TAED); sodium-1-methyl-2 -benzoyloxy benzene-4 sulphonate; sodium-4 30 methyl-3-benzoloxy benzoate; SPCC; trimethyl ammonium toluyloxy-benzene sulphonate; sodium nonanoyloxybenzene

sulphonate (SNOBS) sodium 3,5,5-trimethyl hexanoyl-

oxybenzene sulphonate (STHOBS); and the substituted cationic nitrites. 5 Other classes of bleach precursors for use with the present invention are found in WO0015750, for example 6-

(nonanamidocaproyl)oxybenzene sulphonate.

The precursors may be used in an amount of up to 12%, 10 preferably from 2-10% by weight, of the composition.

The Surfactant The following is intended as a general example of acceptable surfactants for use with a bleaching composition of the 15 present invention. The surfactant may be neutral or charged. A fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain 20 configuration. Preferably the number of carbon atoms in the fatty acid soap is from about 16 to about 18.

This soap, in common with other anionic detergents and other anionic materials in the detergent compositions of this 25 invention, has a cation, which renders the soap water-

soluble and/or dispersible. Suitable cations include sodium, potassium, ammonium, monethanolammonium, diethanol ammonium, t riethanolammonium, tetramethyl ammonium, etc. cations. Sodium ions are preferred although in liquid 30 formulations potassium, monoethanolammonium,

diethanolammonium, and triethanolammonium cations are useful. The soaps are made from natural oils that often contain one 5 or more unsaturated groups and consist of mixtures of components. It is clear that hydrolysation of these natural components yield mixtures of soaps. Examples of natural oils are sunflower oil, olive oil, cottonseed oil, linseed oil, safflower oil, sesame oil, palm oil, corn oil, peanut 10 oil, soybean oil, castor oil, coconut oil, canola oil, cod liver oil and the like, that give mixtures of soaps.

However, also hydrolysis products of purified oils, as listed above, may be employed. Other examples of soaps include erucic acid.

As one skilled in the art will appreciate a cationic may be manufactured, for example, by adding an alkyl halide to an amine thus forming a cationic.

20 In principle the cationic surfactants exhibit the same requirements as listed above for the soap materials, except they need to be quarternised. Without limiting the scope of the invention, suitable cationics may be formed by preparing the quaternary salts from alcohols that were obtained from 25 the corresponding fatty acid. Examples of cationic surfactants based on natural oils include oleylbis(2-

hydroxyethyl)methylammonium chloride and disallow fatty alkyldimethyl ammonium chloride.

30 In general, the nonionic and anionic surfactants of the surfactant system may be chosen from the surfactants

described "Surface Active Agents" Vol. 1, by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing 5 Confectioners Company or in "TensideTaschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds 10 having a hydrophobic group and a reactive hydrogen atom, for example, aliphatic alcohols, acids, amides or alkyl phenols with alkylene oxides, especially ethylene oxide either alone or with propylene oxide. Specific nonionic detergent compounds are C6-C22 alkyl phenol-ethylene oxide condensates, 15 generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C8 Cl8 primary or secondary linear or branched alcohols with ethylene oxide, generally 5 to 40 EO.

20 Suitable anionic detergent compounds which may be used are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals.

25 Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C8-Cl8 alcohols, produced for example from tallow or coconut oil, sodium and potassium alkyl Cg-C20 benzene sulphonates, particularly sodium linear 30 secondary alkyl C1O-Cl5 benzene sulphonates; and sodium alkyl glyceryl ether sulphates, especially those ethers of the

higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum. The preferred anionic detergent compounds are sodium C1l-Cl5 alkyl benzene sulphonates and sodium C12-Cls alkyl sulphates. Also 5 applicable are surfactants such as those described in EP-A-323 177 (Unilever), which show resistance to salting-out, the alkyl polyglycoside surfactants described in EP-A-070 074, and alkyl monoglycosides.

10 Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants pointed out in EP-A-346 995 (Unilever). Especially preferred is surfactant system that is a mixture of an 15 alkali metal salt of a C16-Cl primary alcohol sulphate together with a C12-Cl5 primary alcohol 3-7 NO ethoxylate.

The nonionic detergent is preferably present in amounts greater than 10%, e.g. 25-90% by weight of the surfactant system. Anionic surfactants can be present for example in 20 amounts in the range from about 5% to about 40% by weight of the surfactant system.

Enzymes The detergent compositions of the present invention may 25 additionally comprise one or more enzymes, which provide cleaning performance, fabric care and/or sanitation benefits. Said enzymes include oxidoreductases, transferases, 30 hydrolases, lyases, isomerases and ligases. Suitable members of these enzyme classes are described in Enzyme

- 23 nomenclature 1992: recommendations of the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology on the nomenclature and classification of enzymes, 1992, ISBN 0-12-227165-3, Academic Press.

The composition may contain additional enzymes as found in WO 01/00768 Al page 15, line 25 to page 19, line 29, the contents of which are herein incorporated by reference.

10 Experimental Tomota stain bleaching Tomato-soya oil stained cloths were agitated for 30 minutes at 30 C in an aqueous solution containing 10 mM carbonate buffer (pH 10), 0.6 g/l NaLAS (linear alkylbenzene 15 sulfonate), together with 20 AM of a ligand.

Some of the experiments were conducted in the absence of added peroxyl species and some in the presence of 10 mM hydrogen peroxide as indicated.

After the wash, the cloths were rinsed with water and subsequently dried at 30 C and the change in colour was measured immediately after drying with a Linotype-Hell scanner (ex Linotype) ("t=O") and after 24 h storing in the 25 dark ("t=1"). The change in colour (including bleaching) is expressed as the AE value vs white, so a lower value means a cleaner cloth. The measured colour difference (AK) between the washed cloth and the unwashed cloth is defined as follows:

- 24 HE = [(AL) 2 + (Aa) 2 + (Ab) 2] 1/2 wherein AL is a measure for the difference in darkness between the washed and unwashed test cloth; Aa and Ab are 5 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 l'Eclairage (CIE); Recommendation on Uniform Colour Spaces, colour difference 10equations, psychometric colour terms, supplement no 2 to CIE Publication, no 15, Colormetry, Bureau Central de la CIE, Paris 1978.

Table 1: bleach results on tomato oil measured immediately 15 after drying (t=O) and after 24 h drying (t=1). In all cases in Table 1, no peroxyl source was added to the bleaching solution.

t=0 t=1 LogP Blank 16 16 N-methyl-trispicen (L1) 9 9 2.40 N-ethyltrispicen (L2) g 8 2.75 N-propyl-trispicen (L3) 7 6 3.28 N-hexyltrispicen (L4) 5 N.A. 4.64 The results in Table 1 are indicative of that the ligands shown are of such hydrophobicity to partition sufficiently into an oily stain and are kinetically disposed to form a

transition metal complex in the required time in an oily stain with adventitious transition metals.

Table la: bleach results on tomato oil measured immediately 5 after drying (t=O) and after 24 h drying (t=1). In all cases in Table la, no peroxyl source was added to the bleaching solution.

t=0 t=1 | LogP Blank 17 17 _ MeN4py 15 15 3.57 bicyclam 17 18 0.50 The results in Table la are indicative of the possibility that the ligands shown are not kinetically disposed to form a transition metal complex in the required time in an oily stain with adventitious transition metals and/or are of 15 insufficient hydrophobicity to partition sufficiently into the oily stain.

Table 2: bleach results for tomato oil stains measured immediately after drying (t=O) and after 24 h after drying 20 (t=1). In all cases in Table 2, 10 mM hydrogen peroxide was present in the bleaching solution used.

- 26 t=0 t=1 LogP Blank 16 16 N-ethyl-trispicen (L2) 10 9 2.75 N-propyltrispicen (L3) 8 7 3.28 N-hexyl-trispicen (L4) 6 5 4.64 Syntheses of the ligands 5 L1 has been prepared according to literature procedures (Bernal, J.; et al J. Chem. Soc., Dalton Trans. 1995, 3667 3675).

The ligand N,N-bis(pyridin- 2-yl-methyl)-1,1-bis(pyridin-2 10 yl)-1aminoethane (MeN4py) was prepared as described in EP 0 909 809 A2.

The ligand 5,12-dimethyl-1,5,8,12 tetrsazabicyclo[6.6.2] hexadecane (Bicyclam) was prepared as 15 described in WO 00/29537.

Reaction procedure for L2, L3, L4 The reaction procedure for L2, L3 and L4: To a solution of 2-chloro-methylpyridine (4 mmol) and 1 mmol N-ethyl 20 ethylenediamine (for L2), N-propylethylenediamine (for L3), Nhexylethylenediamine (for L4), resp. in 4 ml water at 70 C was added slowly 0.8 ml 10 NaOH over 10 minutes. The reaction mixture was stirred for an additional 30 minutes at 70 C, after which the reaction mixture was cooled to room 25 temperature. The mixture was extracted with chloroform (3 x 5 ml) and the organic layer were dried over sodium sulphate,

filtered and evaporated under reduced pressure. The material was purified by column chromatography (silica, elutent CH2C12 increased slowly to 10% methanol/CH2Cl2 up to 10% methanol/5% NH4OH/CH2C12). The products were analysed by 5 ES-MS (positive mode). Yields are typically around 50%.

L2: m/z 362.5 (M+H+) L3: m/z 376.4 (M+H+) L4: m/z 418.6 (M+H+)

Claims (1)

1. l i Claims:

   1. A bleaching composition comprising a ligand, L, which forms a complex with a transition metal, and a peroxygen 5 bleach or a peroxy-based or peroxyl-generating bleach system, said organic substance having a hydrophobic substituent and present in the bleaching composition as a free ligand, said hydrophobic substituent increasing hydrophobicity of the transition metal binding moiety of 10 the organic substance, wherein the organic substance has a Log P value of at least 3, with the proviso that N. N. N', N'-tetra(pyridin-2-yl-methyl)ethylenediamine) is excluded. 15 2. A bleaching composition according to claim 1, comprising a peroxygen bleach.

   3. A bleaching composition according to claim 2, wherein the peroxygen bleach comprises sodium percarbonate.

   4. A bleaching composition according to any one of claims 1 to 3, wherein bleaching composition comprises a transition metal sequestrant, the sequestrant having a Log P value of below 1, preferably below 0, most 25 preferably below -1.5.

   5. A bleaching composition according to claim 4, wherein the bleaching composition comprises at least 0.01 wt/wt of the sequestrant.

   À 29 6. A bleaching composition according to claim 5, wherein the bleaching composition comprises at least 0.05 % wt/wt of the sequestrant.

   5 7. A bleaching composition according to claim 1, wherein the ligand has a logP of less 20.

   8. A bleaching composition according any one of claims 1 to 7, wherein L represents a pentadentate or hexadentate 10 ligand of the general Formula (I): R1RlN-W-NRlR2 (I) wherein 15 each R1 independently represents -R3-V, in which R3 represents optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene or alkylene ether, and V represents an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, 20 pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; W represents an optionally substituted alkylene bridging group selected from -CH2CH2-, -CH2CH2CH2-, CH2CH2CH2CH2-, -CH2-C6H4-CH2-, -CH2-C6Hlo-cH2-' and -CH2 25 C1oH6-cH2-; and R2 represents a group selected from R1, and alkyl, aryl and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, 30 amine, and alkylamine.

   9. A bleaching composition according to claim 8, wherein W IS -CH2CH2-

   10. A bleaching composition according to any one of claims 8 5 or 9, wherein R3 is -CH2-.

   11. A bleaching composition according to any one of claims 8 to 10, wherein R1 is pyridin-2-ylmethyl which is optionally substituted by C1-C8alkyl.

   A bleaching composition according to claim 11, wherein R1 is pyridin-2ylmethyl.

   13. A bleaching composition according to any one of claims 8 15 to 12, wherein R2 is selected from the group is consisting of benzyl, pyridin-2ylmethyl, and C1-C20 alkyl. 14. A bleaching composition according to claim 13, wherein 20 R2 is selected from the group consisting of n-C3H7, n C4H9, n-C5H11, n-C6H13, n-C7H15, and n-C8H16.

   15. A bleaching composition according to claim 8, wherein R2 is selected from the group consisting of: CH2(CH2)7Ph, 25 CH2CH2(OCH2CH2)nOCH3; CH2CH2(OCH2CH2)nO(CH2)mCH3 where m = 2, 4, 6, or 8; and, (CH2)p(OCH2CH2) nOCH3 where p = 4, 8, 12, or 16, wherein n = 5, 10, 15 or 20.

   16. A bleaching composition according to any one of claims 1 30 to 7, wherein the ligand is selected from the group consisting of:

   - 31 IN NN: NN

   IN IN

   and