GB2386615A - Bleaching composition - Google Patents

Abstract

A bleaching composition comprises a ligand, L, which forms a complex with a transition metal, the bleaching composition upon addition to an aqueous medium providing an aqueous bleaching medium substantially devoid of 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. The composition provides superior bleaching for oily stains.

Description

238661 5

- 1 ENHANCEMENT OF BLEACHING CATALYSTS

FIELD OF INVENTION

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

BACKGROUND OF INVE_TION

The use of bleaching catalysts for stain removal has been developed over recent years. The recent discovery that some 10 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; W00012657; W00012808; 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 an "air bleaching catalyst", provides superior bleaching composition 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 carrying an oily stain permits targeting of the oily stain 30 with the hydrophobic free ligand. The hydrophobic free ligand in the oily stain forms a complex with adventitious

- 2 - transition metals found in the oily stain which acts together with oxygen present and/or autoxidised material to bleach the chromophore in the stain. Conversely added peroxyl species likely partitions into the oily stain that 5 serves to bleach the chromophore in the stain in conjunction with the formed catalyst. The hydrophobic free ligand in the oily stain forms a complex with adventitious transition metals found in the oily stain which acts together with oxygen present and/or autoxidised material to bleach the 10 chromophore in the stain.

The present invention provides a bleaching composition comprising a ligand, L, which forms a complex with a transition metal, the bleaching composition upon addition to 15 an aqueous medium providing an aqueous bleaching medium substantially devoid of a peroxygen bleach or a peroxybased or peroxyl-generating bleach system, said organic substance having a hydrophobic substituent and present in the bleaching composition as a free ligand, said hydrophobic 20 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.

One or more substituents bound to the ligand increase the 25 ligands hydrophobicity. Nevertheless is important that the ligand has some solubility 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.

30 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 aqua complexes of Manganese(II) and Iron(II) metal ions give rise to fast exchange reactions that are in the order of lot 5 to lo' s-l, see Huheey, Inorganic Chemistry, Principles of structure and reactivity, 2nd Ed, Harper International Edition. Ligands that are kinetically fast in binding to these metals will also give rise to their corresponding complexes rapidly. An example of such a class of ligands lO which are kinetically favourable to forming transition metal complexes are the TPEN/trispicen-ligands. TPEN/Trispicen ligands are generally of the following form: -I R1 \NN: N Without being limited to the theory, we postulate that the 15 transition metal ions present in the stain bind in a hydrophobic matrix to the hydrophobic ligand. It is preferred that the ligancs as used in the present invention are capable of forming a transition metal catalyst after migration to an oily sta-n in the wash such that an active 20 species is formed for bleaching in the absence of an added peroxyl source and/or in the presence of a peroxyl source within 12 hours. This provides for at least the provision of a post-treatment bleaching effect.

25 There is also an example of a class of ligands that are kinetically incompetent o bind to the metal ions, namely

5Il2-dimethyl-ls,8'l2-tetraazabicyclof6.62]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 bleaching composition is substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating 15 bleach system that is other than an alkylhydroperoxide or an alkylhydroperoxide generating system.

The term substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system" should be 20 construed within spirit of the invention. It is preferred that the composition has as low a content of peroxyl species present as possible. The composition of the present invention bleaches a substrate with at least 10 %, preferably at least 50 %, and optimally go of any 25 bleaching of the substrate being effected via oxygen sourced from the air. It is preferred that the bleaching composition of the present invention contains less than 2% wt/wt of an peroxy-based or peroxyl-generating bleach system, more preferably less than 1 wt/wt, and most 30 preferably less than 0.5 % wt/wt.

Go The present invention extends to a method of bleaching a substrate comprising applying to the substrate, in an 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 present invention together with instructions for its use.

10 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 that is then dried, for example as an aqueous spray-on fabric treatment fluid or a wash liquor for laundry 15 cleaning, or a non-aqueous dry cleaning fluid or spray-on aerosol fluid.

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

20 Preferably the textile is a laundry fabric or garment.

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 25 may be effected in a wash cycle for cleaning laundry. More preferably, the treatment is carried out in an aqueous detergent bleach wash liquid.

In a preferred embodiment, the treated textile is dried, by 30 allowing it to dry under ambient temperature or at elevated temperatures. The elevated temperatures are commonly

- 6 provided by a heated agitated environment, as for example found in a tumble dryer, which has been found to accelerate and enhance the air bleaching effect. The effect of ironing the treated textile also serves to accelerate bleaching.

The bleaching method may be carried out by simply leaving the substrate in contact with the bleaching composition for a sufficient period of time. Preferably, however, the bleaching composition is in an aqueous medium, and the 10 aqueous medium on or containing the substrate is agitated.

The bleaching composition may be contacted with the textile fabric in any conventional manner. For example it may be applied in dry form, such as in powder form, or in a liquor 15 that is then dried, for example in 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.

20 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 may be effected in, or as an adjunct to, an essentially conventional wash cycle for cleaning laundry. More 25 preferably, the treatment is carried out in an aqueous detergent wash liquor. The bleaching composition can be delivered into the wash liquor from a ponder, granule, pellet, tablet, block, bar or other such solid form. The solid form can comprise a carrier, which can be particulate, 30 sheet-like or comprise a three-dimensioral object. The carrier can be dispersible or soluble in the wash liquor or

- 7 - may remain substantially intact. In other embodiments, the bleaching composition can be delivered into the wash liquor from a paste, gel or liquid concentrate.

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

10 DETAILED DESCRIPTION OF THE INVENTION

Bleach Catalyst The bleach catalyst is formed in situ and likely forms a -

complex with transition metal ions contained within an oily stain. The ligand for use in the present invention may be 15 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 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 the TPEN and trispicen types, which are a pentadentate or hexadentate ligand of the general Formula (I): R1RlN-W-NRlR2 (I) wherein each R1 independently represents -R3-V, in which R3 30 represents optionally substituted alkylene, alkenylene, oxyalkylene, aminoalkylene or alkylene ether, and

( V represents an optionally substituted heteroaryl group selected from pyridinyl, pyrazinyl, pyrazolyl, pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl; 5 W represents an optionally substituted alkylene bridging group selected from -CH2CH2-, -CH2CH2CH2-, CH2CH2CH2CH2-, -CH2-C6H4-CH2-, -CH2-C6Hlo CH2-, and -CH2-CloH6-cH2-; and R2 represents a group selected from R1, and alkyl, aryl lo and arylalkyl groups optionally substituted with a substituent selected from hydroxy, alkoxy, phenoxy, carboxylate, carboxamide, carboxylic ester, sulphonate, amine, and alkylamine.

15 The ligand forms a transition metal complex preferably of the general formula in the oily stain (AI): [MaLkXn] Ym 20 in which: M represents a metal selected from Mn(II)-(III)-(IV)-

(V), Cu(I)-(II)-(III), Fe (lI)-(III)-(IV)-(V), Co(I)-(II)-

(III), Ti(II) - (III) - (IV), V(II) - (III) - (IV) - (V), Mo(II) -

(TIT)-(IV)-(V)-(VI) and W(IV)-(V)-(VI), preferably from 25 Fe(Il)-(lI)(IV)-(V); L represents a ligand having a Logo of at least 3, preferably a ligand as defined in formula (I); X represents a coordinating species selected from any mono, bi or tri charged anions and any neutral molecules 30 able to coordinate the metal in a mono, bi or tridentate manner;

Y represents any non-coordinated counter ion; 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; 5 m represents zero or an integer from 1 to 20.

Log P values Log P is the n-octanol/water partition coefficient that can be used to relate chemical structure to observed chemical 10 behavior. Log P is related to the hydrophobic character of the molecule.

The Log P values were calculated within Cerius2, using QSAR+, which is a program obtained from Accelrys Inc., 9685 15 Scranton Road, San Diego, CA 92121. The QSAR+ descriptor 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 20 value of logP and molar refractivity. For more information about this descriptor the reader is directed to Leffler and Grunwald (1963).

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

N R1 \NN: :J tN

Log P R1 = methyl _ Rl = e-ethyl 2.75 R1 = pyrldin-2-ylmethyl 3.05 R1 = npropyl 3.28 R1 = n-Bu 3.73 R1 = CH2C6H5 3.99

R1 = n-hexyl 4.64 R1 = n-C18H37 10.12 IN N IN

Log P = 3.86 NN IN Log P = 4.21 NN: IN Log P = 3.32

- 11 NN: W[>J IN

Log P = 3.86 -NN: 5J IN Log P = 5.23 1: L:t Log P = 3.57 \: AN,,N Log P = 0.50 l INN N / N Log P = 0.42

Sequestrant The bleaching composition may contain a transition metal sequestrant. These components may also have calcium and magnesium chelation capacity, but preferentially they show 5 selectivity to binding transition metal ions such as iron, manganese and copper.

Transition metal sequestrants may be present at a level of from 0.005% to 20%, preferably from 0.11 to 10%, more 10 preferably from 0.25% to 7.5% and most preferably from 0.5 to 5% by weight of bleaching composition.

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

Preferred among the above species are diethylene triamine penta (methylene phosphonate), ethylene diamine tri 20 (methylene phosphonate) hexamethylene diamine tetra (methylene phosphonate) and hydroxy-ethylene 1,1 diphosphonate. Other suitable transition metal ion sequestrant for use 25 herein include nitrilotriacetic acid and polyaminocarboxylic acids such as ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, ethylenediamine disuccinic acid, ethylenediamine diglutaric acid, 2hydroxypropylenediamine disuccinic acid or any salts 30 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 diacetic acid or glyceryl imino diacetic 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 3-alanine-N,N'diacetic acid, aspartic acid-N,N'-diacetic acid, aspartic acid-Nmonoacetic 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. Dipicol inic acid and 2-phosphonobutane-1, 2,4-tricarboxylic acid are also suitable. Glycinamide-N,N'-disuccinic acid (GADS), ethylenediamine-N-N'-diglutaric acid (EDDG) and 2hydroxypropylenediamine-N-N'-disuccinic acid (HPDDS) are 25 also suitable.

Builders The bleaching composition may contain as builder a crystalline aluminosilicate, preferably an alkali metal 30 aluminosilicate, more preferably a sodium aluminosilicate (zeolite).

(- The zeolite used as a builder may be the commercially available zeolite A (zeolite 4A) now widely used in laundry detergent powders. Alternatively, the zeolite may be 5 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

Chemicals Ltd. UK.

10 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 1.33, preferably within the range of from 0.90 to 1.20.

15 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.

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.

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, amorphous aluminosilica.es.

Most preferably, the builder is selected from sodium tripolyphosphate, zeolite, 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, dipicolinates, 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 we%; and acrylic polymers, more 20 especially acrylic/maleic copolymers, suitably used in amounts of from 0.5 to 15 we%, preferably from 1 to 10 who.

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

Surfactant The following is intended as a general example of acceptable surfactants for use with a bleaching composition of the 30 present invention. The surfactant may be neutral or charged

- 16 A fatty acid soap used preferably contains from about 16 to about 22 carbon atoms, preferably in a straight chain 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 invention, has a cation, which renders the soap water-

soluble and/or dispersible. Suitable cations include 10 sodium, potassium, ammonium, monethanolammonium, diethanolammonium, triethanolammonium, tetramethylammonium, etc. cations. Sodium ions are preferred although in liquid formulations potassium, monoethanolammonium, diethanolammonium, and triethanolammonium cations are 15 useful.

The soaps are made from natural oils that often contain one or more unsaturated groups and consist of mixtures of components. It is clear that hydrolysation of these natural 20 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 oil, soybean oil, castor oil, coconut oil, canola oil, cod liver oil and the like, that give mixtures of soaps.

25 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 30 manufactured, for example, by adding an alkyl halide to an amine thus forming a cationic.

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 5 the quaternary salts from alcohols that were obtained from the corresponding fatty acid. Examples of cationic surfactants based on natural oils include oleylbis(2-

hydroxyethyl)methylammonium chloride and disallow fatty alkyldimethyl ammonium chloride.

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, 15 Interscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

20 Suitable nonionic detergent compounds which may be used include, in particular, the reaction products of compounds 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 25 or with propylene oxide. Specific nonionic detergent compounds are C6-C22 alkyl phenol-ethylene oxide condensates, generally 5 to 25 EO, i.e. 5 to 25 units of ethylene oxide per molecule, and the condensation products of aliphatic C8-

Cla primary or secondary linear or branched alcohols with 30 ethylene oxide, generally 5 to 40 EO.

Suitable anionic detergent compounds which may be used are usually watersoluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being 5 used to include the alkyl portion of higher acyl radicals.

Examples of suitable synthetic anionic detergent compounds are sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C-C18 alcohols, produced for example from tallow or coconut oil, sodium and potassium 10 alkyl Cg-C20 benzene sulphonates, particularly sodium linear secondary alkyl C1O-Cls 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 15 anionic detergent compounds are sodium C1lCl5 alkyl benzene sulphonates and sodium C12-C1B alkyl sulphates. Also applicable are surfactants such as those described in EP-A-328 177 (Unilever), which show resistance to salting-out, the alkyl polyglycoside surfactants described 20 in EP-A-070 074, and alkyl monoglycosides.

Preferred surfactant systems are mixtures of anionic with nonionic detergent active materials, in particular the groups and examples of anionic and nonionic surfactants 25 pointed out in EP-A-346 995 (Unilever) . Especially preferred is surfactant system that is a mixture of an alkali metal salt of a Cl6-Cl primary alcohol sulphate together with a C12-Cl5 primary alcohol 3-7 EO ethoxylate.

The nonionic detergent is preferably present in amounts 30 greater than 10%, e.g. 25-90% by weight of the surfactant system. Anionic surfactants can be present for example in

- v 19 amounts in the range from about 5% to about 40% by weight of the surfactant system.

Enzymes 5 The detergent compositions of the present invention may additionally comprise one or more enzymes, which provide cleaning performance, fabric care and/or sanitation benefits. 10 Said enzymes include oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases. Suitable members of these enzyme classes are described in Enzyme nomenclature 1992: recommendations of the Nomenclature Committee of the International Union of Biochemistry and 15 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 20 contents of which are herein incorporated by reference.

Experimental Tomota stain bleaching Tomato-soya oil stained cloths were agitated for 30 minutes 25 at 30 C in an aqueous solution containing 10 mM carbonate buffer (pH 10), 0.6 g/l NaLAS (linear alkylbenzene 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 30 hydrogen peroxide as indicated.

- 20 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 5 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: HE = [(AL) 2 + (Aa) 2 + (Ab) 2] 1/ wherein AL is a measure for the difference in darkness between the washed and unwashed test cloth; Aa and Ab are 15 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 20 equations, 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 25 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) 9 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 5 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 10 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 15 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 insufficient hydrophobicity to partition sufficiently into 20 the oily stain.

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

t=0 t=1 LogP Blank 16 16 N-ethyl-trispicen (L2) 10 2.75 N-propyltrispicen (L3) 8 3.28 N-hexyl-trispicen (L4) 6 5 4 64 Syntheses of the ligands L1 has been prepared according to literature procedures lo (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-

yl)-1-aminoethane (MeN4py) was prepared as described in 15 EP 0 909 809 A2.

The ligand 5,12-dimethyl-1,5,8,12 tetraazabicyclo[6.6.2]hexadecane (Bicyclam) was prepared as 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 ethylenediamine (for L2), N-propylethylenediamine (for L3), 25 Nhexylethylenediamine (for L4), resp. in 4 ml water at

- 23 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 temperature. The mixture was extracted with chloroform (3 x 5 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 CH2Cl2 increased slowly to 10% methanol/CH2Cl2 up to 10% methanol/5% NH4OH/CH2Cl2). The products were analysed by 10 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 (11)

- 24 Claims:

1. A bleaching composition comprising a ligand, L, which forms a complex with a transition metal, the bleaching 5 composition upon addition to an aqueous medium providing an aqueous bleaching medium substantially devoid of a peroxygen bleach or a peroxy-based or peroxyl-generating bleach system, said organic substance having a hydrophobic substituent and present in the bleaching lo 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.

15

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

3. A bleaching composition according claims 1 or 2, wherein L represents a pentadentate or hexadentate ligand of the 20 general Formula (I): RlRlNW-NRlR2 (I) wherein 25 each Rl 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, pyrazalyl, 30 pyrrolyl, imidazolyl, benzimidazolyl, pyrimidinyl, triazolyl and thiazolyl;

- 25 W represents an optionally substituted alkylene bridging group selected from -CH2CH2-, -CH2CH2CH2-, CH2CH2CH2CH2-, -CH2-C6H4-CH2-, -CH2C6Hlo-cH2-' and -CH2 C1oH6-cH2-; and 5 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, amine, and alkylamine.

4. A bleaching composition according to claim 3, wherein W is -CH2CH2-.

5. A bleaching composition according to any one of claims 3 15 or 4, wherein R3 is -CH2-.

6. A bleaching composition according to any one of claims 3 to 5, wherein R1 is pyridin-2-ylmethyl which is optionally substituted by C1-C8-alkyl.

7. A bleaching composition according to claim 6, wherein R1 is pyridin-2ylmethyl.

8. A bleaching composition according to any one of claims 3 25 to 7, wherein R2 is selected from the group is consisting of benzyl, pyridin-2ylmethyl, and C1-C20 alkyl.

9. A bleaching composition according to claim 8, wherein R2 30 is selected from the group consisting of n-C3H7, n-C4H9, n-C5H11, n-C6H13, n-C7H15, and n-C8H16.

C4

10. A bleaching composition according to claim 3, wherein R2 is selected from the group consisting of: CH2(CH2)7Ph; CH2CH2(OCH2CH2)nOCH3; CH2CH2(OCH2CH2)nO(CH2)mCH3 where m 5 = 2, 4, 6, or 8; and, (CH2)p(OCH2CH2) nOCH3 where p = 4, 8, 12, or 16, wherein n = 5, 10, 15 or 20.

11. A bleaching composition according to claim 3, wherein the ligand is selected from the group consisting of: NN: NN:

ó) IN IN and