PEROXYNITRITE BASED BLEACHING SYSTEMS

Abstract: Bleaching compositions and methods are provided using peroxynitrite as an active bleaching substance. Stains and soil can be removed from fabrics, household hard surfaces, dentures and other substrates.

Description: PEROXYNITRITE BASED BLEACHING SYSTEMS This invention relates to bleaching compositions and to methods employing these compositions for cleaning substrates, especially fabrics, hard surfaces and dentures Many household and personal care products are formulated with a peroxygen material to effect removal of stain and soil Typical materials which have been used in commerce are hydrogen peroxide, sodium perborate, sodium percarbonate, benzoyl peroxide, peracetic acid (generated through precursor compounds such as N,N,N',N'- tetraacetyl ethylene diamine (TAED)) and persulphate (Oxone®) Each of these has at least one important limitation For instance, hydrogen peroxide, perborate and percarbonate require activating catalysts Often the catalysts are expensive and in manufacturing environments may act as skin sensitisers Instability is another problem with peroxygen materials Peroxides are also aggressive against dyes resulting in colour damaged substrates (e.g fabrics) Considerable research has therefore been conducted to discover alternative bleaching systems Peroxynitrite is a free radical nitric oxide variant which has attracted considerable biochemical study Free radical nitric oxide. «NO. an otherwise relatively toxic classified gas indirectly regulates the relaxation of vascular smooth muscle of blood cells in humans It also plays an important role as a secondary messenger molecule in the nervous system See R F Furchgott, J V Zawadzki, Nature (London), 1980, 288, 373, R M J Palmer, A G Ferrige, S Moncada, Nature. 1987, 327_, 524, and L J Ignarro. G M Buga, K S Wood, R E Burns. G Chaudhuri. Proc. Nat/. Acad. Sci., USA, 1987, 84, 9265 An article by S Moncada, R M J Palmer, E A Higgs. Pharmacol. Rev., 1991 43. 109 reported generation of peroxynitrite in vivo from L-arginine by the enzyme »NO-synthase The realisation that •NO is generated in biological systems has led to an explosion of new research in physiology, pathology and pharmacology More recent investigations have shown that «NO reacts in a diffusion controlled reaction with super oxide, a reduced form of oxygen, to yield peroxynitrite The latter is stable in alkaline solutions See R E Huie, S Padmaja. Free Rad. Res. Commun., 1993, 1^, 195 Several experimental studies have employed peroxynitrite as an oxidising agent for various inorganic and organic substrates See A M Al-Ajlouni, E S Gould, Inorg. Chem., 1996, 35 . , 7892 and references cited therein Lipid oxidation has also been investigated Soybean phosphatidylcholine liposomes were oxidised to malondialdehyde and conjugated dienes, accompanied by oxygen consumption However, no significant lipid peroxidation occurred above pH 9 5 See R Radi, J S Beckman, K M Bush, B A Freeman, Arch. Biochem. Bioph ., 1991, 288(2). 481 Evident from the foregoing background information is that peroxynitrite has attracted considerable academic interest but few practical applications have been considered for this material Accordingly, it is an object of the present invention to provide another tool for the bleaching and cleaning of substrates, especially fabrics and household hard surfaces Another object of the present invention is to provide a bleaching composition effective at relatively low concentrations thereby achieving a cost effective stain removal system Still another object of the present invention is to provide a method for bleaching stained substrates such as clothes, household hard surfaces including dishes, tableware, sinks, toilets and the like, and even dentures Other objects of the present invention will become apparent through the following description and examples It has now been found that peroxynitrite can operate as an effective bleach against stains and soils Consumer and industrial articles can be effectively bleached thereby, to remove stains and soils present on such articles Accordingly, in one aspect, the present invention provides a bleaching composition for removing stains from substrates comprising (i) peroxynitrite, and (ii) up to 50 % by weight of a surfactant Furthermore, in another aspect, the present invention provides a method for bleaching a substrate, especially laundry and household hard surfaces such as dishes, tableware, sinks and toilets, comprising contacting the substrate with peroxynitrite in an aqueous medium In a further aspect, a method is also provided for inhibiting microbial growth on substrates, especially flexible or hard surfaces, by contacting the substrate with a medium, preferably an aqueous medium, comprising peroxynitrite in an amount effective to kill microorganisms In yet a further aspect, the present invention provides a method for treating the oral cavity to brighten teeth, by application of peroxynitrite within the oral cavity In another aspect still, the present invention provides a composition for inhibiting microbial growth in the oral cavity (e.g plaque, tartar and gingivitis), and preferably also for brightening teeth, by application of peroxynitrite within the oral cavity Peroxynitrite can be obtained in a number of ways, many of which have been summarised by R M Uppu. G L Squadrito, R Cueto and W A Pryor, Methods of Enzymology, Vol. 269, 26, pages 285-295 (1996) Among the methods are the reaction of ozone with azide ions, autooxidation of hydroxylamine, reaction of hydrogen peroxide with nitrous acid, reaction of hydrogen peroxide with alkyl nitrites, reaction of »NO with hydrogen peroxide, reaction of »NO with solid potassium super oxide, and reaction of •NO with O 2 formed simultaneously from a single source The latter method is a particularly preferred one It involves the auto oxidation of sydnones and sydnonimines with respective structures I and II as follows (I) (ii) wherein R, R' and R" independently may be hydrogen or a hydrocarbyl group having from 1 to 50 carbon atoms selected from substituted and unsubstituted alkyl, cycloalkyl, alkene, phenyl. aryl and heterocyclic radicals Typical substituents on R, R' or R" may be functional groups with up to 20 carbon atoms selected from cyano, nitro, halo, carboxylate, thio. alkoxy, carboalkyoxy, hydroxy, sulphono, sulphato, phospho, amino. alkyl, cycloalkyl, acyl, amino, aminoalkyl, thioalkyl, sulphoxyalkyl. carboxyester, polyalkoxy and quaternary di- or tri- alkylammonium radicals and mixtures thereof Typical heterocyclic radicals include cycloaliphatic and cycloaromatic rings incorporating an oxygen, sulphur and/or nitrogen atom within the ring system Representative nitrogen heterocycles include pyridine. morpholine, pyrrole, imidazole, triazole, tetrazole, pyrrolidine, piperidine and piperazine Suitable oxygen heterocycles include furan, tetrahydrofuran and dioxane Sulphur heterocycles may include thiophene and tetrahydrothiophene Structures I and II also can be substituted with rings wherein R may be joined to R' or R" . Likewise, R' may be joined to R' ' Illustrative but not limiting examples of *NO generating compounds are as follows 3-mo holinosydnonimine-N-ethylcarbamide, 2-(N-nιtrosomorpholinamino)isobutyronitrile, 3-(thiomorpholino-S,S-dioxide)sydnonimine hydrochloride, 3-(4-methylsulphonylpiperazino)sydnonimine hydrochloride, 3-(4-dιmethylaminosulphonylpiperazino)sydnonimine hydrochloride, 3-(thiomorpholino-S-oxide)sydnonimine hydrochloride, 3-[4-(4-tolylsulphonyl)-piperazino]sydnonimine hydrochloride, 3-(4-ethoxycarboxypiperazino)sydnonimine hydrochloride, 3-(N-methyl-N-tetrahydrothien-3-yl)sydnonimine hydrochloride, 3-dimethylaminosydnonimine hydrochloride, 3-piperidinosydnonimine hydrochloride, 3-(2,2,6,6-tetramethylpiperidino)sydnonimine hydrochloride, 3-(2,6-dimethylpiperidino)sydnonimine hydrochloride, 3-(2,2,6,6-tetramethylmorpholino)sydnonimine hydrochloride, 3-(2,6-dιmethylthiomorpholino-S,S-dioxide)sydnonimine hydrochloride, 3-(N-t-butyl)-2-hydroxyethylamino)sydnonimine hydrochloride, 3-(2,2-dιmethyl-4-ιsopropylpiperazino)sydnonimιne hydrochloride, 3-(2,5.-dιmethylpyrrolidino)sydnonimιne hydrochloride, 3-(2-hydroxycyclohexylamino)sydnonimιne ethylcarbamide, 3-(N,N-dibenzylamino)sydnonimine hydrochloride, 3-cyclohexylaminosydnonimine hydrochloride, 3-(2-hydroxyethylamino)sydnonimine hydrochloride For purposes of experimentation, peroxynitrite was generated through the auto oxidation of SIN-1 in a procedure schematically presented below SIN-1 (3-Morpholinosydnonimine) production of peroxynitrite \ ^ 'Nθ | 7 - • λ j - Y O N— N CN -* O N =N CN H+ * NO + θ2" 0=NOO- The amount of the peroxynitrite in compositions according to the present invention should be sufficient to provide effective bleaching activity for the substrate used Suitably, the amount ranges from about 0.01 to about 30%, preferably from about 0.1 to about 20%. optimally from 0.5 to 10% by weight Peroxynitrite bleach systems of the present invention may be employed for a wide variety of purposes, but are especially useful in the cleaning of laundry When intended for such purpose, the peroxynitrite will usually also be combined with a surfactant, and optionally with detergent builders and other ingredients of laundry detergent formulations The surfactant may be naturally derived, or a synthetic material selected from anionic. nonionic, amphoteric. zwitterionic, cationic actives and mixtures thereof Many suitable actives are commercially available and are fully described in the literature, for example in "Surface Active Agents and Detergents", Volumes I and II, by Schwartz, Perry and Berch The total level of surfactant may range up to 50% by weight, preferably being from 0 5 to 50% by weight of the composition, more preferably from 0 5 to 50% by weight, most preferably from 4 to 25% by weight Synthetic anionic surfactants are usually water-soluble alkali metal salts of organic sulphates and sulphonates having alkyl radicals containing from about 8 to about 22 carbon atoms Examples of suitable synthetic anionic surfactants are sodium and ammonium alkyl sulphates, especially those obtained by sulphating higher (C 8 -C 18 ) alcohols produced for example from tallow or coconut oil, sodium and ammonium alkyl (C 9 -C 20 ) benzene sulphonates, sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum, sodium coconut oil fatty acid monoglyceride sulphates and sulphonates, sodium and ammonium salts of sulphuric acid esters of higher (C 9 -C 18 ) fatty alcohol-alkylene oxide, particularly ethylene oxide, reaction products, the reaction products of fatty acids such as coconut fatty acids esterified with lsethionic acid and neutralised with sodium hydroxide, sodium and ammonium salts of fatty acid amides of methyl tauπne, alkane monosulphonates such as those derived by reacting alpha-olefins (C 8 -C 20 ) with sodium bisulphite and those derived by reacting paraffins with SO 2 and Cl 2 and then hydrolysing with a base to produce a random sulphonate, sodium and ammonium C 7 .C 12 dialkyl sulphosuccinates, and olefin sulphonates, which term is used to describe the material made by reacting olefins, particularly C 10 -C 20 alpha-olefins. with SO^ and then neutralising and hydrolysing the reaction product The preferred anionic surfactants are sodium (C j ] -C j 5 ) alkylbenzene sulphonates, sodium (C 12 -C l s ) alkyl glycerol sulphonates, sodium (C 16 -C ] S ) alkyl sulphates and sodium alkyl ether sulphates Examples of suitable nonionic surfactants which may be used, preferably together with the anionic surfactants, include in particular the reaction products of alkylene oxides, usually ethylene oxide, with alkyl (C 6 -C 2 ) phenols, generally 5-25 EO, i.e. 5-25 units of ethylene oxide per molecule; the condensation products of aliphatic (C 8 -Cι 8 ) primary or 5 secondary linear or branched alcohols with ethylene oxide, generally 2-30 EO, and products made by condensation of ethylene oxide with the reaction products of propylene oxide and ethylene diamine Other so-called nonionic surface-actives include alkyl polyglucosides, long chain tertiary amine oxides, and saccharide fatty amides such as methyl gluconamides 10 Amphoteric or zwitterionic surfactants such as alkylamidopropyl betaines and lauroamphoacetates can also be used in the compositions of the invention Amounts of these surfactants may range from 0 1 to 30% by weight Soaps may be incorporated into the compositions of the invention, preferably at a level of less than 30% by weight They are particularly useful at low levels in binary 15 (soap/anionic) or ternary mixtures together with nonionic or mixed synthetic anionic and nonionic compounds Soaps which are used are preferably the sodium, or less desirably potassium, salts of saturated or unsaturated C 10 -C 24 fatty acids or mixtures thereof The amount of such soaps can be varied between 0 5 and 25% by weight, with lower amounts of 0.5 to 5% being generally sufficient for lather control Amounts of soap between 2 and 20 20%), especially between 5 and 15, are used to give a beneficial effect on detergency This is particularly valuable in compositions used in hard water where the soap acts as a supplementary builder. The relative molar amounts of peroxynitrite and surfactant may range from 1 • 1 to 1 :5,000, preferably from 1 10 to 1 : 100 25 The bleaching compositions of the invention may also contain a detergency builder Builder materials may be selected from (1) calcium sequestrant materials, (2) precipitating materials, (3) calcium ion-exchange materials and (4) mixtures thereof In particular, the compositions of the invention may contain any one of the organic or inorganic builder materials, such as sodium or potassium tripolyphosphate, sodium or potassium pyrophosphate, sodium or potassium orthophosphate, sodium carbonate, the sodium salt of nitrilotriacetic acid, sodium citrate, carboxymethylmalonate, carboxymethyloxysuccinate, tartrate mono- and di-succinate, oxydisuccinate, crystalline or amorphous aluminosilicates and mixtures thereof. Polycarboxylic homo- and co-polymers may also be included as builders and to function as powder structurants or processing aids Particularly preferred are polyacrylic acid (available under the trademark Acrysol from the Rohm and Haas Company) and acrylic-maleic acid copolymers (available under the trademark Sokalan from the BASF Corporation) and alkali metal or other salts thereof These builder materials may be present from 1 to 80 % by weight, preferably from 10 to 60 %) by weight. Upon dispersal in a wash water, the initial amount of peroxynitrite may range anywhere from 0 01 to 250 ppm per liter of water, preferably from 1 to 100 ppm Surfactant may be present in the wash water from 0 05 to 1 0 grams per liter, preferably from 0 15 to 0.20 grams per liter. When present, the builder amount will range from 0 1 to 3 0 grams per liter Apart from the components already mentioned, the bleaching compositions of the invention can contain any of the conventional additives in the amounts in which such materials are normally employed in bleaching or detergent compositions. Examples of these additives include dye transfer inhibition agents (e.g polymers based on N- vinylpyrrolidone and N-vinylimidazole), lather boosters such as alkanolamides, particularly the monoethanolamides derived from palmkernel fatty acids and coconut fatty acids, lather-depressants such as alkyl phosphates and silicones. anti-redeposition agents such as sodium carboxymethylcellulose and alkyl or substituted alkylcellulose ethers, stabilisers such as ethylene diamine tetraacetic acid and phosphonic acid derivatives (Dequest®), fabric softening agents, inorganic salts such as sodium sulphate, and, usually present in very small amounts, fluorescent agents, perfumes, enzymes such as proteases, cellulases, lipases and amylases, germicides and colourants Among consumer products which may incorporate this invention are laundry detergents, laundry-bleaches, hard surface cleaners (e.g scouring cleansers), toilet bowl cleaners, automatic dishwashing compositions and even denture cleaners Stained consumer products benefiting from treatment with compositions of this invention may include clothes and other fabrics; household fixtures and appliances such as sinks, toilet bowls and oven ranges; tableware such as drinking glasses, dishes, cookware and utensils, and even dentures Hair colorants may also be formulated with the bleaching compositions of this invention The bleaching system of this invention may also be applied to industrial uses such as for the bleaching of wood pulp Scouring cleansers may be formulated with peroxynitrite at levels ranging from 0 001 to 30 % by weight These hard surface cleaners will generally contain an abrasive material usually in the form of water-insoluble particles with particle size diameters ranging from 1 to 250 μm, the particles usually having a specific gravity of from 0 5 to 5, and a Mohs' hardness of 2 to 7 Preferably, the diameter of the particles is from 10 to 150, most preferably from 20 to 100 μm The specific gravity is preferably from 1 to 3 Examples of suitable abrasive materials include, but are not limited to, quartz, pumice, pumicite, titanium dioxide, silica sand, calcium carbonate, zirconium silicate, diatomaceous earth, whiting, feldspar, alumina, corundum, volcanic ash, bentonite, magnesium oxide, magnesium carbonate, chalk, dolomite, shell, talc, calcite, sodium bicarbonate and mixtures thereof Amounts of the abrasive material may range from 1 to 99 %, preferably from 60 to 80 % by weight Besides the abrasive and bleach, the hard surface cleaner may also contain a surfactant and a carrier Typically the carrier is water Surfactants have already been described with respect to laundry formulations, and the surfactants would also be suitable for cleaning hard surfaces The bleaching system of the present invention may be delivered in a variety of product forms including powders, on sheets or other substrates, in pouches, in tablets, in aqueous liquids, or in nonaqueous liquids such as liquid nonionic detergents. The present invention will be further illustrated by reference to the embodiments shown in the following examples. All parts, percentages and proportions referred to herein are by weight unless otherwise indicated EXAMPLE 1 General Peroxynitrite was prepared by the reaction of sodium azide with ozone generated in a Fischer Model 500 M Ozonator More specifically, oxygen was purged for 150 minutes through the Ozonator (flow rate lOO mL min ). Resultant ozone was directed through a glass frit into a chilled ice bath solution of 100 mL of 0.1 N sodium azide (adjusted to pH 12 with IN NaOH). A 10%o solution of potassium iodide in a 0 07 M phosphate buffer at pH 7 was employed to destroy any excess ozone Maximum yields of peroxynitrite obtained were 36 mM as determined by ultraviolet analysis Bleach Studies Stain bleaching was measured reflectometrically using a Garner BYK Colorgard System Reflectometer 2000/05 Bleaching was indicated by an increase in reflectance, reported as ΔΔR In general, ΔΔR of one unit is perceivable in a paired comparison while ΔΔR of two units is perceivable monadically In reporting the reflectance change, the change in reflectance caused by general detergency has been accounted for Thus ΔΔR can actually be expressed as ΔΔR = /ΔR peroxynitrite • + detergent] - Adetergent where ΔR is the reflectance difference of the stained fabric after and before washing TABLE I BC-1 Cloth Results Stain bleaching experiments were conducted in a Terg-O-Tometer open to the air utilising 200 mL buffer solution (0 1 M phosphate buffer) Experiments were run at 25°C and pH 12 except as otherwise noted Peroxynitrite was dosed at 6 mM initial concentration The substrate was a tea (BC-1) stained cotton cloth The experiments were conducted in the dark to eliminate any possible light induced activation and insure reproducibility of the results See Table I A further study examined the effect of pH For these experiments, the Terg-O- Tometer conditions were 25°C, 0 3 M phosphate buffer. 30 minutes terging time and 6 mM initial peroxynitrite concentration Table II reports these results TABLE II BC-1 Cloth Bleaching at Various pH Levels An experiment was conducted to compare the bleaching effect between peroxynitrite and a typical organic peracid, i.e peracetic acid The conditions employed were 25°C, pH 10 with 0 1 M phosphate buffer, 30 minutes terging time and 6 mM initial peroxynitrite concentration The ΔΔR on BC-1 stained cloth for peroxynitrite and peracetic acid were respectively 18 35 and 14 35 From the foregoing experiments it is evident that peroxynitrite is operative across a broad pH spectrum but is most effective against tea stains in the pH 8-11 range and is at least as effective as peracetic acid Other experiments were conducted to evaluate effectiveness against a variety of common stains other than tea These are reported in Table III TABLE III Stain Removal Profile * the use of prewashed cloths (with Surf®) was necessary because for many non- prewash cloths the stain bled into solution where peroxynitrite bleached the dissolved stain and did not attack the stain with the fabric/wash liquor interface In those cases where this effect cannot occur, e.g. BC 1 , the ΔΔR values were consistent with or without the prewash conditions 25°C, pH 10, phosphate buffer. 30 min terg time, 6mM initial peroxynitrite concentration Evident from Table III is that peroxynitrite has effectiveness against a variety of different types of stains Some types of bleaching agents are quite detrimental to cloth, especially cotton This is one reason why not every bleaching agent is suitable for cleaning fabrics A degradation study was conducted on bleached, mercerised, combed cotton broadcloth Table IV reports the results of that study No significant fabric degradation was noted after a 5 hour wash Peroxynitrite is therefore viewed as a substance suitable for contact with this sensitive fabric TABLE IV Burst Strength Test Conditions Jars 1 & 2 (control) 6 cloths (each) in 150 mL of 0 03 M sodium azide solution at pH 12 Jars 3 & 4 6 cloths (each) in 150mL of 6 mM peroxynitrite solution at pH 12 Mini-terg temperature was set at 40°C and washed for 5 hours EXAMPLE 2 A pair of typical laundry powdered detergent formulations employing peroxynitrite are outlined below EXAMPLE 3 A typical hard surface cleaner formula is outlined below EXAMPLE 4 A typical denture cleansing paste composition is outlined below The foregoing description and examples illustrate selected embodiments of the present invention. In light thereof, variations and modifications in accordance with the present invention will be apparent to one skilled in the art.

Claims: CLAIMS: 1 A bleaching composition for removing stains from substrates comprising (i) peroxynitrite as active bleaching agent, and (ii) up to 50 % by weight of a surfactant 2 A composition according to claim 1, comprising from 0 01 to 30 %> by weight of peroxynitrite 3 A composition according to claim 1 or claim 2, comprising from 0 5 to 50 % by weight of surfactant 4 A composition according to any one of claims 1 to 3. comprising from 1 to 80 % by weight of a detergency builder 5 A composition according to any one of claims 1 to 4. comprising an enzyme selected from proteases, cellulases, lipases, amylases and mixtures thereof 6 A composition according to any one of claims 1 to 5, formulated into a form selected from a powder, sheet, pouch, tablet, aqueous liquid and nonaqueous liquid 7 A composition according to any one of claims 1 to 6, wherein the peroxynitrite is generated from a precursor compound 8 A method for bleaching a stained substrate, comprising contacting the stained substrate with peroxynitrite in an aqueous medium 9 A method according to claim 8. wherein the aqueous medium comprises a surfactant 10 A method according to claim 9, wherein the peroxynitrite and surfactant are present in a molar ratio from 1 1 to 1 5,000 11 A method according to claim 10, wherein the molar ratio of peroxynitrite to surfactant ranges from 1 10 to 1 : 100 12 A method according to any one of claims 8 to 1 1. wherein the substrate is selected from fabrics, household fixtures, dishes and tableware 13 A method according to any one of claims 8 to 1 1, wherein the substrate is a denture 14 A method according to any one of claims 9 to 13, wherein the aqueous medium contains from 0 01 to 250 ppm of peroxynitrite and from 0 05 to 1 0 gram of surfactant per liter of medium 15 A method for inhibiting microbial growth on flexible or hard surface substrates comprising contacting the flexible or hard surface substrate with an aqueous medium comprising peroxynitrite in an amount effective to kill microorganisms

Inventors: MADISON STEPHEN ALAN, MCCALLUM JEREMY ELLIOT BONGARD, ROJAS-WAHL ROY UWE, MADISON, STEPHEN, ALAN, MCCALLUM, JEREMY, ELLIOT, BONGARDT, ROJAS-WAHL, ROY, UWE
Applicants: UNILEVER NV, UNILEVER PLC
Application year: 1998
Main classification: C11D3
IPC codes: C11D3, C11D17