BLEACH CATALYSTS

Abstract: The invention relates to bleach catalysts for use in cleaning or detergent compositions. The bleach catalysts used are water-soluble complexes of (a) one or more cobalt ions and, as ligand, (b) one or more aminated and/or alkylated mono- or oligo-saccharides, optionally in reduced or oxidised form, and salts thereof. The complexes according to the invention are good bleach catalysts and have high hydrolytic stability.

Description: BLEACH CATALYSTS This invention relates to bleach catalysts for use in cleaning or detergent compositions. European laundry detergents usually contain oxygen-based bleaching agents such as sodium perborate or sodium percarbonate . These bleaches work well at temperatures above 60°C, but to boost their overall effectiveness at today' s relatively low washing temperatures (e.g. 40-60°C) , they are most commonly employed with so-called bleach activator compounds. The bleach activator, an example in commercial use of which is tetraacetylethylenediamine (TAED) , is typically employed at a level of 3-6% in the detergent and reacts εtoichiometrically with the perεalt to yield a stronger oxidising agent, e.g. peracetic acid. This oxidant is better able to bleach stains than hydrogen peroxide and also has superior biocidal activity. However, as washing temperatures continue to decline, as a result of the demand for greater energy efficiency, even the commercially used activated bleach systems are becoming less attractive since their performance is known to decrease rapidly below 40°C. Another drawback of these types of activator is their significant cost contribution to the detergent formulation, especially in proportion to that of the persalt component. Their rate of dissolution at low temperatures is also likely to reduce their effectiveness and may cause localised dye damage. The development of interfacially active bleach activators, which react with persalts to produce peracids which are in turn interfacially active, has improved the performance of oxygen bleaches under certain conditions . The technology has meant that lower concentrations of the bleach system in the wash liquor are needed to give equivalent performance since the bleach is effectively targeted to the stains. Sodium nonanoyloxybenzene sulphonate (SNOBS) as described in US-A-4,412 , 934, is an example of this type of activator. Although this disclosure has resulted in the successful introduction of perborate bleach-based detergents into the United States, where lower detergent concentrations are typically employed, it has done little to improve detergent performance at temperatures below 40°C. Much effort is being expended in the search for new organic bleach activators, however at present none has emerged which fulfils all the requirements, which must include (I) significantly improved bleach activity below 40°C, (II) fast dissolving rate, (III) low cost, (IV) ease of procesεability into detergent formulations, (V) storage stability, (VI) compatibility with other detergent ingredients, and (VII) a non-toxic nature. Another approach considered has been the use of pre-formed peracids as bleaches. An example of this is diperoxydodecanedioic acid (DPDDA) . Although this, and other examples of pre-formed peracids, can lead to better bleaching performance than tetracetylethylenediamine (TAED) activated perborate, the peracids generally need -stabilising coatings (as described for example in US-A-4, 100, 095) . Their use can also cause pin-hole damage to dyed fabrics . Yet another approach taken within the detergents industry has been the use of bleach catalysts which work with oxygen bleaches such as sodium perborate or sodium percarbonate . EP-A-237,111 and EP-A-443,651 describe bleaching compositions comprising a water soluble complex of manganese with a multidentate ligand, such as hydroxycarboxylic acid and non-carboxylate polyhydroxy compounds respectively. EP-A-272,030 and EP-A-392,592 disclose Co(III)amine complexes (e.g. [Co (NH 3 ) 5 C1] Cl 2 ) and Co(biεpyridylamine)Cl 2 complexes respectively, as effective catalyεtε for activating hydrogen peroxide compounds in removing stainε from εubεtrates, such as fabricε . Other patent εpecificationε, for example WO 96/23859, WO 96/23860 and WO 96/23861, diεclose cobalt catalysts such as [Co(NH 3 ) 5 Cl] Cl 2 and Co-SALEN type complexes to provide enhanced cleaning/bleaching benefits in automatic dishwashing detergents. Catalystε described by Hage et.al. in Nature 369, 637-639 (1994) and also in EP-A-458,397 and EP-A-458,398 are exampleε which give a conεiderable enhancement to perεalt bleaching of εtains on fabrics during washing at temperatures below 40°C. However, these catalystε are prone to cauεing unacceptable dye and fabric damage due to the formation of radical catalyst decomposition products. Another important characteriεtic of bleach catalysts is their hydrolytic stability. Lack of hydrolytic stability of the catalysts can result in precipitation out, under alkaline wash conditionε, of insoluble transition metal oxides or hydroxides resulting in most undesirable brown staining. It iε thus important that the complex employed aε catalyεt muεt have good hydrolytic activity on the one hand but εtill have good effectiveneεε aε bleach catalyεtε on the other hand. It has now surpriεingly been found that water- εoluble complexes of cobalt with aminated and/or alkylated mono- or oligo-saccharides, optionally in reduced or oxidised form, and salts thereof have high effectiveneεε aε bleach catalyεtε and have high hydrolytic stability. According to one aspect of the present invention, there iε provided a water-εoluble complex of (a) one or more cobalt ions and, as ligand, (b) one or more aminated and/or alkylated mono- or oligo-saccharideε, optionally in reduced or oxidiεed form, and εaltε thereof for uεe aε a bleach catalyεt, in particular for a cleaning or detergent composition. Suitably, in the complex used according to the present invention the cobalt ion(s) (a) is/are σomplexed with (b) one or more compoundε of the general formula I wherein R 1 iε εeleσted from CH 2 OH, C0 2 H, C0 2 θ M β (wherein M is an alkali metal or ammonium ion) and groups of the formula (a) to (d) and n iε an integer from 1 to 3; one of R 2 and R 3 iε H and the other iε εelected from H, OH and groupε of the formula (e) to (h) and m iε an integer from 1 to 3 ; one of R 4 and R 5 iε H and the other iε OH; one of R 6 and R 7 iε H and the other iε OH or NH 2 ; and one of R 8 and R 9 is H and the other is OH, OCH 2 (CH 2 ) p CH 3 (wherein p iε an integer from 6 to 16), or a group of the formula provided that one of R 6 and R 7 is NH 2 and/or one of R 8 and R 9 is OCH 2 (CH 2 ) p CH 3 , Also in the complex used according to the present invention, the cobalt ion(ε) (a) may be σomplexed with (b) one or more compoundε of the general formula II RlO[ClH 2 l-k(OH) k ]CHRll (II) H2 wherein each of R 10 and R 11 , which may be the same or different, representε H, CH 2 OH, CO-H or CO jj 'Η ® (wherein M iε as defined above) ; and each of 1 and k iε an integer of 2 to 5 and k is equal to or less than 1. Preferably the cobalt ion(s) (a) iε/are complexed with (b) D-mannoεamine, D-glucoεamine, or D-galactosamine, or with (b) one or more alkyl polyglucoεideε having a degree of polymerisation up to 5 and wherein the alkyl groups contain 8 to 18 carbon atoms. Suitably the complex used according to the invention iε a Co (II) or a Co (III) complex. The complexeε uεed according to the invention may be prepared by a method which compriεes contacting in aqueous solution (A) a water-soluble compound capable of releaεing Co (II) or Co (III) ionε on addition to water with (B) one or more aminated and/or alkylated mono- or oligo-εaccharideε, optionally in reduced or oxidised form, and salts thereof . For example, cobalt chloride hexahydrate (0.53 g) and mannoεamine hydrochloride (24.1 g) were diεεolved in 500 ml of demineralised water, the pH of the solution was adjuεted to 10 uεing 1M εodium hydroxide εolution and the solution was evaporated to dryneεs in a rotary evaporator. The molar ratio of the ligand to cobalt may generally be between 1:1 and 500:1 with ratios in the region 50:1, e.g. 20:1 to 80:1 being particularly suitable. According to another aspect of the present invention there iε provided a cleaning or detergent composition comprising: (I) a bleaching agent, and (II) as bleach catalyst, a water-soluble complex aε defined according to the present invention. The cobalt bleach catalyεt can, and indeed is preferably, formed in situ at the beginning of the wash cycle. Accordingly, according to a further aspect of the invention, there is provided a cleaning or detergent compoεition compriεing: (I) a bleaching agent, and, aε precursors for a bleach catalyst, (IIA) a water-soluble compound capable of releasing Co (II) or Co (III) ions on addition to water, and (IIB) one or more aminated and/or alkylated mono- or oligo-saccharides, optionally in reduced or oxidised forms, and saltε thereof. The water-εoluble Co 2+ or Co 3+ compound (IIA) εhould be a compound which complexeε preferentially with the compounds (IIB) in the composition. These compounds may be cobalt chloride or weakly complexed cobalt compounds. The complexes used according to the invention promote bleaching activity and this iε particularly noticeable at low temperatureε (i.e. 20 to 40°C) . The bleaching agent (I) will generally be a peroxy compound which liberateε hydrogen peroxide in water, preferably sodium perborate or sodium percarbonate . The ligand component of the bleach catalyst (b) or precursor ingredient (IIB) may suitably be a cyclic ligand of formula I. Some of the ligands of formula I have surface active properties which provide further cleaning benefits towardε oily and particulate εolids in particular. The ligand compoundε used according to the invention are derived from εtarches or naturally occurring carbohydrates and thus are environmentally acceptable and toxicologically inert. The compoεitionε according to the invention may be laundry detergentε or hard εurface cleanerε including automatic diεhwaεhing detergentε and may comprise other ingredients well known to those skilled in the art. They may contain a bleach activator e.g. TAED. The compositions according to the invention may contain a surfactant, for example, an anionic surfactant such as an alcohol sulphate or linear alkyl benzene sulphonate or non-ionic εuch aε an alcohol ethoxylate. In addition, the compoεitionε according to the invention will generally contain builders such as alumino- εiliσateε (e.g. zeolite A) , layered εilicates, phosphates particularly sodium tripolyphosphate, trisodiu citrate, sodium carbonate or sodium borate. Equally, there may be preεent polymeric additiveε εuch aε maleic/acrylic copolymers which act as co-builderε, and soil release polymers such as polyethylene oxide terephthalate . The compositionε according to the invention may alεo contain suds suppreεεorε εuch aε soap; enzymes εuch aε lipaεe, amylaεe, cellulaεe and proteaεe; optical brighteners such as stilbene derivativeε; εequeεtrantε or a combination of εequeεtrantε with low affinity for cobalt but which will complex with other tranεition metalε or if not, at a low enough level not to impair σatalyεt performance, and flow aidε/fillerε εuch aε εodium εulphate. Typically for detergent formulationε according to the invention, assuming a typical usage level of detergent of 5 g/1 (Europe) , a suitable level of cobalt chloride hexahydrate and, for example, a mannosamine ligand in the detergent formulation would be in the order of 0.024 wt% and 1.08 wt% reεpectively. In use the cobalt level may for example be in the range from 0.85 to 85 μmoleε Co/litre of wash liquor (0.05 to 5 ppm) . More detailed information on typical detergent σompositionε is disclosed in, for example, WO 92/06161. The invention is further deεcribed in the following Examples . EXAMPLE 1 Compariεon of tea εtain bleaching performance of mixed cobalt εalt/organic polyol/perεalt εyεtemε with organically activated perεaltε at 40°C. Test wash liquor was prepared composed of 1 litre of deionised water to which waε added aε appropriate: (a) 5 x 10- 6 M CoCl 2 .6H 2 0 (CoCl 2 .6H 2 0) (b) 8.6 x 10 "3 M H 2 0 2 , aε peroxygen source to provide active oxygen in solution, and 8.6 x 10 "3 M sodium metaborate, as borate buffer to simulate use of sodium perborate (PBS) , (c) 8.6 x 10 "3 M H 2 0 2 , as peroxygen source, and 5.7 x 10 "3 M sodium carbonate aε carbonate buffer to εimulate εodium percarbonate (PCS) , (d) 6.6 x 10 "4 M tetraacetylethylenediamine (TAED) , aε an activator, (e) 2.5 x 10 "4 M of the εpeσified polyhydroxy compound to provide a bleach system as set out in Table I below. Bleaching tests were carried out in a Terg-o- tometer (United States Testing Co.) at 40°C. The pH was monitored and maintained at 10 using dilute sulphuric acid or sodium hydroxide solution as necessary. Four 10 x 10 cm 2 swatches of tea stained cotton (BCD were used in the bleaching εtudieε. The wash duration was 31 minutes. The reflectance of all swatcheε waε meaεured before and after washing on a HunterLab UltraScan XE spectrophotometer . The change in reflectance of the waεhed and unwaεhed clothε (ΔR) waε calculated at the εtated wavelength and the four ΔR valueε were averaged to give an overall value per waεh. The reεultε are εhown in Table I below. TABLE I Bleach Syεtem ΔR, 460 PBS 6.27 PBS + TAED 8.40 PCS 7.18 PCS + TAED 7.90 PBS + CoCl 2 .6H 2 0 9.86 PCS + CoCl 2 .6H 2 0 11.75 PBS + CoCl 2 .6H 2 0 + D-mannosamine 10.25 PCS + CoCl 2 .6H 2 0 + D-mannosamine 11.89 PBS + CoCl 2 .6H 2 0 + Simulsol SL 10 * 11.81 PCS + CoCl 2 .6H 2 0 + Simulεol SL 10 11.23 PBS + CoCl,.6H,0 + D-glucoεamine 9.84 PCS + CoCl,.6H,0 + D-glucosamine 10.96 PBS + CoCl 2 .6H 2 0 + D-galactosamine 10.27 PCS + CoCl 2 .6HjO + D-galactosamine 10.71 * Simulsol SL 10 (ex SEPPIC) is a mixture of alkyl polyglucosideε having a degree of polymeriεation up to 4, 1-4 (50%) and 1-6 (50%) interglucoεidic linkageε, and wherein the alkyl groupε are predominantly deσyl . Hydrolytic εtability teεtε were carried out at a mole ratio of 10 ligand: lCo 2+ aε CoCl 2 .6H 2 0 (0.5 mmol ligand/0.05 mmol Co 2+ ) . Where indicated, PBS was added aε 8.6 x 10" 3 M εodium metaborate and 8.6 x 10 "3 M H 2 0 2 , and PCS aε 5.7 x 10 "3 M εodium carbonate and 8.6 x 10 "3 M H 2 0 2 . The test solutions were prepared in deionised water and all εolutions were adjuεted to pH 10 before the addition of the Co. The reεults are shown in Table II below. TABLE II Solution Composition Stable* Stable* after 1 after 24 hour hours CoCl,.6H,0 yeε no CoCl 2 . 6H 2 0 + PBS yeε no CoCl 2 . 6H 2 0 + PCS yeε no CoCl 2 6H 2 0 + D-mannosamine + PBS yeε yeε CoCl 2 .6H 2 0 + D-mannosamine + PCS yeε yeε CoCl 2 .6H 2 0 + Simulsol SL 10 + PBS yeε yeε CoCl 2 .6H 2 0 + Simulsol SL 10 + PCS yeε yeε CoCl 2 .6H 2 0 + D-glucosamine + PBS yeε yeε CoCl 2 .6H 2 0 + D-glucoεamine + PCS yeε yeε CoCl 2 .6H 2 0 + D-galactoεamine + PBS yeε yes CoCl 2 .6H 2 0 + D-galactoεamine + PCS yes yeε * Stable εolutionε are defined aε optically tranεparent and containing no visible precipitate EXAMPLE 2 Comparison of tea stain bleaching performance of mixed cobalt εalt/organic polyol/perεalt εyεtemε with organically activated persaltε at 20°C, 30°C and 40°C. Teεt waεh liquors were prepared, as in Example 1, to provide bleach systems as set out in Table III below. Bleaching test and reflectance measurements were carried out as in Example 1, except that the bleaching test temperatureε uεed were 20°C, 30°C and 40°C. The reεults are shown in Table III below. TABLE III EXAMPLE 3 Effect of peroxide and cobalt salt concentration upon tea εtain bleaching performance at 40°C. Teεt waεh liquor waε prepared compoεed of 1 litre of deioniεed water to which waε added, as appropriate: (a) 5 x 10 "6 or 10 x 10 "6 M CoCl 2 .6H 2 0 (b) 8.6 x 10 "3 M H 2 0 2 and 8.6 x 10 "3 sodium metaborate or 17.2 x 10 "3 M H 2 0 2 and 17.2 x 10 "3 M sodium metaborate (σ) 6.6 x 10 "4 M tetraacetylethylenediamine (TAED) (d) 2.5 x 10 "4 M of the specified polyhydroxy compound to provide the bleach system as set out in Table IV below. Bleaching tests and reflectance measurements were carried out aε in Example 1. The reεultε are εhown in Table IV below. TABLE IV * A high reflectance value waε obtained from the waεh containing Co (5xl0 "6 M) + H 2 0 2 (17.2 mmol), however thiε combination would be unacceptable under laundry conditionε due to itε hydrolytic inεtability. EXAMPLE 4 Comparison of performance of PBS with and without addition of Co salt/Simulsol SL 10 complex againεt a variety of stains and soils in washing tests at 40°C. Test wash liquor was prepared composed of 1 litre of deionised water to which waε added, aε appropriate (a) 8.6 x 10 "3 M H 2 0 2 and 8.6 x 10 "3 M εodium metaborate (PBS) , (b) 6.6 x 10 "4 M TAED, (c) 5 x 10 -6 M CoCl 2 .6H 2 0, (d) 2.5 x 10 "4 M Simulεol SL 10 to provide a bleach compoεition aε εet out in Table V below. Bleaching tests were carried out using four 10 x 10 cm 2 swatches of each of the indicated sampleε. The protocol for the bleaching and bleaching/cleaning εtudieε was as the bleaching teεtε of Example 1. Reflectance was measured as described in Example 1. The resultε obtained were aε in Table V below. TABLE V a EMPA 114 = red wine stained cotton b BCl = tea stained cotton °BC2 = coffee stained cotton d CS-5S = mayonnaise/annatto soiled cotton β EMPA 101 = carbon black/olive oil soiled cotton

Claims: CLAIMS 1. Uεe of a water-εoluble complex of (a) one or more cobalt ionε and, as ligand, (b) one or more aminated and/or alkylated mono- or oligo-saccharideε, optionally in reduced or oxidiεed form, and εaltε thereof, aε a bleach σatalyεt . 2. Uεe according to claim 1 wherein, in the complex, the cobalt ion(ε) (a) iε/are complexed with (b) one or more compoundε of the general formula I wherein R 1 iε εelected from CH 2 OH, C0 2 H, C0 2 θ M β (wherein M iε an alkali metal or ammonium ion) and groups of the formula (a) to (d) and n iε an integer from 1 to 3 ; one of R 2 and R 3 iε H and the other iε εelected from H, OH and groupε of the formula (e) to (h) and m iε an integer from 1 to 3 ; one of R 4 and R 5 iε H and the other iε OH; one of R s and R 7 iε H and the other iε OH or NH 2 ; and one of R 8 and R 9 iε H and the other iε OH, OCH 2 (CH 2 ) p CH 3 (wherein p iε an integer from 6 to 16), or a group of the formula provided that one of R 6 and R 7 iε NH 2 and/or one of R 8 and R 9 is OCH 2 (CH 2 ) p CH 3 . 3. Use according to claim 1 wherein, in the complex, the cobalt ion(s) (a) iε/are complexed with (b) one or more compounds of the general formula II RlO [ClH 2 l-k (OH) ] CHR l (ID NH 2 wherein each of R 10 and R 11 , which may be the same or different, represents H, CH 2 0H, C0 2 H or (wherein M iε aε defined above) ; and each of 1 and k iε an integer of 2 to 5 and k iε equal to or less than 1. 4. Use according to claim 1 wherein, in the complex, the cobalt ion(s) (a) is/are complexed with D- mannosamine, D-glucosamine, or D-galactosamine. 5. Use according to claim 1 wherein, in the complex, the cobalt ion(s) (a) iε/are complexed with (b) one or more alkyl polyglucosides having a degree of polymerisation up to 5 and wherein the alkyl groupε contain 8 to 18 carbon atoms. 6. Use according to any one of the preceding claims wherein, in the complex, the or each cobalt ion (a) is a Co (II) or Co (III) ion. 7. A cleaning or detergent composition compriεing (I) a bleaching agent, and (II) as bleach catalyst, a water-soluble complex aε defined in any one of claimε 1 to 6. 8. A cleaning or detergent compoεition comprising: (I) a bleaching agent, and, as precursors for a bleach catalyst (IIA) a water-soluble compound capable of releasing Co (II) or Co (III) ions on addition to water, and (IIB) one or more aminated and/or alkylated mono- or oligo-saccharides, optionally in reduced or oxidised form, and salts thereof. 9. A composition according to claim 8 wherein there iε used as component (IIA) cobalt chloride. 10. A composition according to claim 8 or 9 wherein there is used as component (IIB) one or more compounds of the general formula I wherein R 1 iε selected from CH 2 OH, C0 2 H, C0 2 θ M # (wherein M is an alkali metal or ammonium ion) and groups of the formula (a) to (d) and n is an integer from 1 to 3; one of R 2 and R 3 is H and the other is selected from H, OH and groups of the formula (e) to (h) and m iε an integer from 1 to 3 ; one of R 4 and R 5 iε H and the other iε OH; one of R 6 and R 7 iε H and the other iε OH or NH 2 ; and one of R 8 and R 9 iε H and the other is OH, OCH 2 (CH 2 ) p CH 3 (wherein p is an integer from 6 to 16), or a group of the formula provided that one or R 6 and R 7 is NH 2 and/or one of R 8 and R 9 iε OCH 2 (CH 2 ) p CH 3 . 11. A composition according to claim 8 or 9 wherein there iε uεed aε component (IIB) one or more compounds of the general formula II RlO [C1H21 -k (OH) k- CHRll (ID NH 2 wherein each of R 10 and R 11 , which may be the same or different, representε H, CH 2 OH, C0 2 H or C0 2 β M* (wherein M iε as defined above) ; and each of 1 and k is an integer of 2 to 5 and k iε equal to or less than 1. 12. A composition according to claim 8 or 9 wherein there is used as component (IIB) D-mannosamine, D- glucosamine, or D-galactosamine. 13. A composition according to claim 8 or 9 wherein there is used as component (IIB) one or more alkyl polyglucosideε having a degree of polymerisation up to 5 and wherein the alkyl groupε contain 8 to 18 carbon atoms . 14. A composition according to any one of claims 7 to 13 wherein the bleaching agent (I) is a peroxy compound which liberates hydrogen peroxide in water, preferably sodium perborate or sodium percarbonate .

Inventors: BUNTON CLIFFORD, GREENHILL-HOOPER MICHAEL JOHN, RENDER CARMEL MARIA, BUNTON, CLIFFORD, GREENHILL-HOOPER, MICHAEL, JOHN, RENDER, CARMEL, MARIA
Applicants: BUNTON CLIFFORD, GREENHILL HOOPER MICHAEL JOHN, RENDER CARMEL MARIA, UNITED STATES BORAX INC, BUNTON, CLIFFORD, GREENHILL-HOOPER, MICHAEL, JOHN, RENDER, CARMEL, MARIA, U.S. BORAX INC.
Application year: 1998
Main classification: C11D3
IPC codes: C11D3