CA2155633A1 - Oxidising agents - Google Patents

Abstract

N-acyl compounds known as bleach activators especially tetraacetylalkylene diamines, are reacted with a peroxygen source in aqueous solution at an acidic pH to form an oxidising product which is a stronger oxidising agent than the peroxygen source used as the starting material. The product solution is used for instance as a bleach or disinfectant. The activator and disinfectant source may be provided as a concentrate product ready for dilution with components able to produce acidic pH in the aqueous solution. The product is, for instance in particulate solid form containing granules of activator and different granules of peroxygen source.

Description

WO94/18298 PCT/GB94/00~9

2~-5~ ~

Oxidisina Aqents The present invention relates to the in situ production of peroxygen-h~-C~ oxidising species from a peroxygen source and an activator followed by the use of the product as an oxidising agent, for instance as a bleach or a biocide.
It-is very well known in the la~,d~ detergent field to use a combination of peroxygen bleach precursor (or peroxygen source) and bleach activator in the same or separate compositions. The bleaching activators are acyl donors. The bleach precursor and activator, when added to the aqueous laundry liquor react together in a reaction involving attack by peroxide anion on the activator to form a peroxygen bleaching species usually the peroxy acid anion. The conditions of laundry liquors are invariably alkaline, usually having a pH of at least 9. The activator and peroxygen source do not react together during storage and are themselves stable under storage conditions.
It is known to coat or agglomerate bleach activators to increase their stability on storage in a laundry detergent composition and/or to affect their dissolution characteristics in the wash liquor. Fatty acids have been used and in WO-A-9213798 solid organic acids such as monomeric aliphatic hydroxy carboxylic acids including citric, lactic and glycolic acids, are incorporated into activator particles. In EP-A-0028432 bleach particles are stabilised for storage by incorporating acidic components.
The particles are incorporated into conventional A 1 k~ e laundry detergents.
In Report no. R202, October 1992, of the Wool Res~rch organisation of New Zealand, the shrink proofing of wool by treatment with aqueous sodium perborate is described. The reaction is carried out at alkaline pH and in some instances tetraacetylethylenediamine is used as an activator. The effect of carrying out the treatment at neutral pH is investigated and it is concluded that that at WO94/18298 PCTtGB94/00~9 æi~6~3 acidic .pH the perhydroxy anion does not decompose to an active oxidising species. The conc~ntration of sodium perborate in the aqueous solution is 0.IM whenever neutral or acidic pH was used. Acidification is by the i~ oduction of acetic acid into the solution of sodium perborate.
In American Dyestuff Reporter, June 1992, 34-41, El-Sisi et al describe the activation of hydrogen peroxide used in the preparation of cotton fabrics in a desizing, bleaching and scouring step by urea. The effect of varying the pH between 4 and 10 is investigated. The concentration of peroxide is always 8g/1 (0.24M) or less. The temperature of the reaction is 95C. The mechAn;sm of activator postulated in this disclosure is different from the meçhAn; which is thought to be responsible for the activation properties of compounds incorporated into laundry detergents as bleach activators.
Organic peroxy acids are well known as useful oxidising agents for a wide range of specific oxidation reactions that they perform in high-to-quantitative yield.
A review of the various methods known for the preparation of peroxy acids is available in "Organic Peroxidesn, volume 1, D. Swern Ed, Wiley Interscience (1970) 313-335. Most of the reactions described use the corresponding carboxylic acid, the acid anhydride, the acid chloride or the aldehyde as the starting materials for instance for a perhydrolysis reaction using hydrogen peroxide. One of the reactions uses the alkaline pe~hydLolysis of imidazolides of carboxylic acids to form the peroxy carboxylic acids (Folli, U et al (1968) Bollettino, 26, 61-69).
It is known to produce peracetic acid, a ~L-ony oxidising agent, in situ by reaction of acetic acid and hydrogen peroxide, for instance to be used in ~rox;~Ation reactions. The advantage of using the peracid rather than hydrogen peroxide itself is that it is a stronger oxidising agent. Peracids are however unstable and can be dangerous to tr~n~port in bulk. The problem with the in situ W094/l~98 2 1~ ~ 6 ~ ~ PCT/GB94/00~9 reaction of acetic acid and hydrogen peroxide is that water must be removed to drive the reaction or else a large ecc of one of the reactants must be used, nece~citating complex separation and recycling steps. Acetic anhydride has also been used in place of acetic acid as starting material for this in situ reaction. The conditions during the in situ reaction step and subsequent oxidation reaction will be acidic. Acetic acid and acetic anhydrides as starting materials for an in situ reaction require special precautions on handling and so are not suitable for use in a domestic environment. Acetic anhydride is water sensitive and so requires special storage conditions.
In US-A-3551087 and US-A-3374177 a process is described in which formaldehyde or a formic acid ester or formamide is reacted with hydrogen peroxide to form performic acid solution which is then used as a bleach.
The reaction and the bleaching take place in an acidic environment. The bleaching process is part of the industri&l dyeing process for wool and silk. Performic acid is, however, extremely unstable and even relatively dilute solutions can explode at ambient temperatures. It is furthermore corrosive and an irritant, as is formic acid, the by-product of the bleaching reaction. For these reasons formate activators are undesirable, especially for use in a domestic or other non-industrial context.
In EP-A-0545594 tooth whit~ni ng compositions are described which contain pe~o~y acetic acid as the bleaching agent. Compositions into which peroxy acetic acid itself is incorporated are acidic. It is suyye~Led that the peroxy acetic acid can be generated in situ by the reaction in aqueous solution of tetraacetyl ethylene diamine and sodium perborate. In the specific examples of that embodiment of the invention the aqueous solution formed when the perborate and activator are dissolved is alkaline.
It would be desirable to find a system with the stability and advantages of the bleach ~e~u~or/activator combinations used in the laundry detergent inAl~ctry, but where the reaction between precursor and activator and/or the subsequent oxidation (including bleaching) step are carried out under acidic conditions and at relatively low concentrations.
In a new process according to the invention a peroxygen source is reacted with an activator compound which is an N-acyl compound in which the acyl moiety has at least 2 carbon atoms in a first step in aqueous solution under acidic conditions to form an oxidising product.
In the process the oxidising product is found to be a stronger oxidising agent than the peroxygen source.
In such a process the peroxygen source is reacted with an activator compound of the formula I
o R2 ~ 3 R -C-N-R
in which R1 is an alkyl, alkenyl, aralkyl, alkaryl or aryl group, any of which groups has up to 24 carbon atoms and may be substituted or unsubstituted, and -NR2R3 is a leaving group in which R and R are independently selected from H, C124-alkyl, -alkenyl, -aralkyl, alkaryl or -aryl groups, and carbonyl-containing groups having at least 2 carbon atoms in which the carbonyl group is joined to the nitrogen atom in the formula I, in a first step in aqueous solution under acidic conditions to form an oxidising species which is a stronger oxidising agent than the peroxygen source itself.
Without being bound by theory, the present inventors believe that the mechanism of reaction is that the N-acyl activator is perhydrolysed, the N-containing part of the molecule acting as leaving group, to form the respective percarboxylic acid of the acyl group.
It is believed therefore that the product of the reaction of I with peroxygen source is a percarboxylic acid of the formula II
o R -C-O-O-H II

AMENDED S~EET

~ 215~63~

In one embodiment of the process, the product containing the stronger oxidising species is subsequently used as a bleaching agent in an aqueous environment at a pH
of less than 7.
In another embodiment of the invention the product of the first step (hereinafter sometimes called the perhydrolysis step for convenience) is subsequently used as an oxidising agent in an oxidising step which is carried out without removal of any by-products from the first perhydrolysis step.
It is preferred that R is an aliphatic group preferably a C118-alkyl or -alkenyl group, or an aryl group.
In the present invention alkyl groups may be straight branched or cyclic.
In the compound of the formula I the groups R2 and R3 may be joined to form a cyclic group. R1 may further or alternatively be joined to either R or R to form a cyclic group. These cyclic groups may include heteroatoms, for instance oxygen or optionally substituted nitrogen atoms, carboxyl groups as well as -CH2- groups or substituted derivatives thereof. They may be saturated or unsaturated.
Substituents on R , R and R can include hydroxyl, =N-R4 in which R is selected from any of the groups represented by R2 and R and is preferably lower alkyl, amine, acyl, acyloxy, alkoxy, aryl, aroyl, aryloxy, aroyloxy, halogen, amido, and imido groups and the like as well as other groups not adversely affecting the activity of the compound.
In the invention the compound of the formula I is preferably any N-acyl compound which has been described as a bleach activator for use in laundry detergents. The compound of the formula is preferably an amide derivative such as an acyl imidazolides as described by Folli et al (op cit) and N,N-diacyl amides, for instance, triacetyl ethanolamine or, most preferably tetraacetyl 5 t~r N, ~ L~r ~

W0~4/l~98 ~ 33 PCT/GB94/~02~9 ethylenediamine (TAED). Other exa~ples of N-acyl derivatives are:
a) 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine(DADHT);
b) N-alkyl-N-suphonyl carbonamides, for example the compounds N-methyl-N-mesyl acetamide, N-methyl-N-mesyl benzamide,N-methyl-N-mesyl-p-nitrobenzamide,andN-methyl-N-mesyl-p-methoxybenzamide;
c) N-acylated cyclic hydrazides, acylated triazoles or urazoles, for example monoacetyl maleic acid hydrazide;
lo d) O,N,N-trisubstituted hydroxylamines, such as O-benzoyl-N,N-succinyl hydroxylamine, O-p-nitrobenzoyl-N,N-succinyl hydroxylamine and O,N,N-triacetyl hydroxylamine;
e) N,N'-diacyl sulphurylamides, for example N,N'-dimethyl-N,N'-dimethyl-N,N'-diacetyl sulphuryl amide and N,N'-diethyl-N,N'-dipropionyl sulphurylamide;
f) 1,3-diacyl-4,5-diacyloxy-imidazolines, for example 1,3-diacetyl-4,5-diacetoxy imidazoline, 1,3-diacetyl-4,5-dipropionyloxy imidazoline;
g) Acylated glycolurils, such as tetraacetyl glycoluril and tetraproprionyl glycoluril;
h) Diacylated 2,5-diketopiperazines, such as 1,4-diacetyl-2,5-diketopiperazine,1,4-dipropionyl-2,5-diketopiperazine and 1,4-dipropionyl-3,6-dimethyl-2,5-diketopiperazine;
i) Acylation products of propylene diurea and 2,2-dimethyl propylene diurea, especially tAe tetraacetyl or tetrapropionyl propylene diurea and their dimethyl derivatives;
j) Alpha-acyloxy-(N,N')polyacyl malonamides, such as alpha-acetoxy-(N,N')-diacetyl malonamide.
k) O,N,N-trisubstituted alkanolamines, such as O,N,N-triacetyl ethanolamine.
l) N-acyl lactams, such as N-benzoyl-caprolactam, N-acetyl caprolactam, the analogous compounds formed from C410 lactams.
m) N-acyl and N-alkyl derivatives of substituted or unsubstituted phthalimide, succinimide and of imides of wo 94,l82g8 2 ~ ~ 5 ~ 3 3 PCT/GBg4l0022g other ~ihA~iC carboxylic acids, having 5 or more carbon atoms in the imide ring.
In the process of the invention the precursor peroxygen source may be hydrogen peroxide itself, but is alternatively an inorganic persalt, for instance a percarbonate or a perborate, for instance sodium perborate, or an organic peroxide such as benzoyl peroxide or urea peroxide.
The pH in the perhydrolysis step is preferably less than 6.5 throughout the entire reaction. Since the pH
tends to drop during the reaction due to the formation of the percarboxylic acid, this means that the pH should be acidic and preferably less than 6.5 at the beginning of the reaction. Preferably the pH is less than about 6.0, at the start of the reaction. The pH is usually more than 2.0, at the start of the reaction and preferably throughout the reaction, preferably more than 5.o.
In the perhydrolysis reaction the amount of water present is preferably at least as much as (in terms of moles) as the peroxgyen source. Where the peroxygen source is hydrogen peroxide itself, the concentration of hydrogen peroxide is preferably less than 70% weight/volume (that is weight of hydrogen peroxide based on volume of water plus hydLoyen peroxide plus other components in the mixture concerned). Preferably the concentration is less than 60% weight by volume and more preferably less than 30%
w/v. Where the product of the reaction is to be used in a domestic environment or other environment where it is difficult to take special precautions in handling the products, it is preferred for the concentration to be less than 15 or even 10% w/v for instance 5% w/v or less. The concentration is usually at least 0.2%, preferably at least 1% w/v, more preferably at least 2% w/v. Where the peroxygen source is other than hydrogen peroxide then the concentration is preferably such as to give the equivalent available oxygen as the quoted conc~ntrations of hydrogen peroxide. Expressed in molar terms, for instance, the _ W094/18298 PCT/GB94/00~9 2~55~33 concentration of hydLo~en peroxide or ~LLoLate or percarbonate is suitably in the range O.OlM to lOM, preferably in the range 0.05 or O.IM to 5M, more preferably in the range O.2M to 2M often less than IM, in the perhydrolysis reaction mixture.
In the perhydrolysis step of the reaction the temperature is preferably in the range O to 95C, more preferably in the range 10 to 80C. The invention is most useful when the temperature is less than 60C, or even less lo than Sooc~ for instance less than 40C ox even around room temperature. The temperature is often above 20C. The temperature in any subsequent oxidising step is preferably in the same ranges as the temperature during the perhydrolysis step and is preferably substantially the same temperature especially where the product solution is immediately used for instance as a bleach or disinfectant.
A particular advantage of using activators for the peroxygen source is that the oxidising product tends to be formed at a relatively low temperature, for instance less than hand hot which is advantageous from a safety point of view.
The activator compound is generally used in an amount such that it is capable of providing in the range 0.1 to 5.0 equivalents of acyl groups based on the moles of peroxygen source, preferably in the range 0.2 to 1Ø The amount is often less than stoichiometric, for instance up to o.9 or 0.8 of the stoichiometric amount. For instance tetraacetyl ethylenediamine reacts as an activator to donate one acyl group from each nitrogen atom and so to provide 0.2 equivalents acyl ~ou~ per mole of peroxide, 0.1 mole of TAED is needed for total reaction. Often less than this is used, although the optimum amount ~ep~AR upon the degree of increase in oxidising performance compared to the costs of the peroxygen source and activator.
The present invention provides also use of a composite product comprising all the starting materials for the perhydrolysis reaction. Preferably the product can simply -W094/18298 21~ S 6 ~ ~ PCT/GB94/00~9 .

be added to water to provide the entire reaction mixture.

The product therefore comprises a peroxygen source, an N-acyl activator compo~ln~ preferably of the formula I, as well as components for rendering the pH of an aqueous solution to which the components of the product are added acidic if n~cecs~ry~ though in some circumst~nces the peroxygen source itself may be sufficiently acidic that no extra acidifying component is n~

An acidifying component may comprise an acid and/or lo buffering material. The component may comprise a polybasic organic acid, such as a polybasic carboxylic acid such as citric, succinic, or adipic acid or sulphamic acid.

Alternatively the component may react with a by-product of the perhydrolysis reaction to make an acid. Where perborate is used, borate is a by-product and so any component known to react with borate to drop the pH, eg cis-1,2-diols, eg glycols and polyols, boric acid or sodium dihydrogen phosphate, can be used. Such acidifying components are also suitable for use with other inorganic persalts.

Although the composite product may contain the individual components in two or more separate compositions, for instance one of which contains the peroxygen source (for instance an agueous solution of hy~o~en peroxide as a concentrate for dilution or ready for use without further dilution) and another of which contains the activator, for instance of the formula I, it is preferred for a mixture of at least two of the components to be provided in a single composition, in which the components do not react, and which is preferably substantially waterfree. It is preferred to provide at least the activator and acidifying component, if any, as a mixture in a single composition in a form in which they are stable. Such a ~L~Ct which does not contain peroxygen source, may for instance, be added to an aqueous solution of peroxygen source, such as hydLo~en peroxide, which is readily commercially available, in the form of 60%, 20% lo~ or, preferably 5% w/v, or less, WO94/18298 ~15~ PCT/GB94/00229 solution. It is most preferred for the activ~tor, peroxygen source and any acidifying component to be present in a single composition.
The products may be in liquid form, for instance in a non-aqueous liquid medium, in which the components may be dissolved or dispersed. For instance particles of acti~ator with protective coatings, for instance produced by microencapsulation tech~iques or spray coating of solid activator, may be suspended in an aqueous, or non aqueous, solution of peroxygen source. As an alternative to a solution of peroxygen source that component may also be suspended in the liquid medium, either in a separate liquid phase or in particulate dispersed phase, particles of solid peroxygen source optionally being coated with a protective coating. Coated particles of either peroxygen source or activator may be disrupted simply by being diluted into water or physically disrupted by applying abrasion.
Preferably the product is in solid form, for instance as a mixture of particles of the individual components or, more preferably, comprising particles each of which comprise all of the comron~nts. Such particles may be provided by techn;ques similar to those used in the laundry detergent industry, for instance including particles produced by spray drying liquid slurries, by granulation t~-hn;ques using binders for instance synthetic or natural polymers (or derivatives) or by melt bl~;nq followed by extrusion or other techn;ques.
The composite product may include other additives, for instance stabilisers which stabilise the product before use, as well as stab;lis rs for the -~Lonyer oxidising species formed in the reaction, ~sr~c~ y heavy metal sequestrants. The new product may also include surfactants to act as wetting agents and inorganic salts, for instance which affect the physical properties of the solid form or act as diluent or to increase the rate of disintegration of dissolution of the product. Other ingredients may be included depending on the form of the product and the final WO94/18298 ~ 3~ PCT/GB94/00~9 ., 11 application of the reaction product, for instance perfumec, abrasives.
Preferably the product contains the active ingredients in a~ O~L iate relative quantities so that when the composition is diluted (or the compositions are mixed) with - water the first step of the reaction proce~R at the optimal rate and at the desired pH. The activator and peroxygen source are for instance present in relative amounts such that 5% to 150% of the stoichiometric amount of activator (for complete reaction with the peroxygen source) is provided. Preferably the amount of activator is 10 to 100%, more preferably 20 to 80% of the stoichiometric amount.
The reaction product of the perhydrolysis reaction is preferably used immediately, without removal of any by-products or addition of other materials, in a second step in which it is used as an oxidising agent, bleaching or disinfecting agent. Sometimes it may be desirable to add additional ingredients for the c~con~ step such as pH-adjusters, and surfactants/wetting agents which maycationic, anionic, amphoteric or non-ionic. Other additives which may improve the second step of the process are for instance disinfectants, biocides, slimicides, enzymes, inhibitors or radical scavengers, abrasives etc.
Cobiocides are particularly valuable where the primary objective of the s?con~ step is disinfection/
sterilisation.
The second step of the process of the present invention may be used as a bleaching/disinfection process, by which we mean any process in which unwanted colour is reduced or removed, non-coloured stains are reduced or removed and/or a substrate is disinfected. For instance the C~con~ step may include proç~s-~- in which hard surfaces in domestic, industrial or institutional

3~ applications are cle~nc~, fabrics tfor instance during fabric manufacture and dyeing) or the solution is used in water, effluent or sewage treatment as a biocide, in pulp WO94/18298 a~ 3~ PCT/GB94100229 and paper bleaching, paper dP ~ nk ~ wood bleaching, in fibre and fabric manufacture, a biocide, fungicide, bacteriocide, sporicide and/or viricide, as a contact lens disinfectant or general disinfectant for use inter alia in general environmental clean up. Furthermore the secon~
step may be used in food production for instance to bleach flour, beverages, or edible oils in the food and brewing industries, for instance to clean pipes used for beverages, or, in cosmetic uses such as hair blea~hing or tooth or denture whitening and disinfecting. The product of the first step may alternatively be used as an oxidising agent in organic synthesis eg for use in epoxidation reactions of alkenes or as a catalyst. It can be used as a curing agent for certain adhesives.
Since the reaction can be carried out at a relatively low concentration it can be carried out without special precautions, for instance in a domestic or institutional environment.
Compositions which are suitable to be diluted direct into water to allow the first and second steps of the reaction to proceed without further additions, may be categorised in four convenient categories.
The first category comprises liquid formulations which include a surfactant. These compositions will be suitable for use as hard surface cleaners and other uses where surface active disinfection and/or bleaching is required, for instance floor cle~ni~ compositions, domestic and institutional hard surface cleaners, toilet disinfectants, general toiletries disinfectant, sanitising bottles, including glass and plastic bottles, and pipe cleaning compositions. For most of these uses it will be desirable for the composition to be relatively low foaming, although for some, for instance toilet disinfecting and general toiletries disinfectant, it may be desirable for the composition to have a relatively high foam. The use of suitable surfactants which will foam is well known in the art. For compositions which are desired to be low foam, it wo 94/18298 2 1 ~ ~ ~ 3 3 PCT/GBg4/00229 .

may desirable to incorporate anti-foaming agents, for instance soap or silicone anti-foams. Liquid formulations including surfactants may be useful in other applications such as for use to bleach fibres or fabrics, such as nappies or in fabric production, cellulo~e fibres, - especially in paper de-inking operations, and in general environmental clean-up operations.
A second category of composition comprises liquid formulations but which contain no surfactants. These may lo be useful where no surface activity is n~c~cc~ry~ for instance in effluent and water treatment, in toilet disinfectants, for use as a swimming pool treatment, for colour removal from chemicals, from pulp during paper making or recycling, in general industrial sterilisation and in some domestic sterilisation situations, for instance as a general toiletry disinfectant, in denture cleaning compositions, in sanitising glass and plastic bottles or other containers, as well as in certain environmental clean-up operations. ~urthermore, where the composition is to be used as a general industrial oxidation reaction, it may be undesirable to include a surfactant.
The liquid formulations mentioned above may be pourable liquids, which are aqueous or non-aqueous, or may be in gel or paste form. Furthermore the compositions may be two-phase, for instance a cream form. Alternatively the compositions could be in the form of a mousse (where the composition contains surfactant) by the injection of a gas, especially for domestic hard surface cl~n; ng operations.
A further category of composition is in solid form and includes a surfactant. The general uses of these compositions are similar to those for which the liquid formulations including a surfactant are useful, as mentioned above.
A further category of formulation comprises a solid composition but without surfactant. These compositions are useful in the same categories of uses as the liquid formulations without surfactant. The compositions may, in WO94/18298 2~ 14 PCT/GB94/00~9 solid ~orm, be more storage stable, since it is in general easier to keep the bleach activator and peroxygen donor compound in separate particles and prevent them coming into contact with one another during storage. It is furthermore easier to isolate other components of the composition from one another and from the bleach components, especially where storage sensitive compounds such as enzymes, other biocides or perfumes are present.
Solid compositions may be in the form of particulate mixtures or may be tabletted. Tabletted formulations, or even gr~ r formulations, may include agents to increase the dissolution rate of the compositions upon addition to water. For instance suitable components incorporating into tablets aid disintegration of the tablet. Such ingredients may create effervescence, for instance; a suitable component is sodium bicarbonate, or other alkali metal bicarbonate.
The compositions may also contain ingredients to assist in their application or stability or which improve their appearance, for instance thickeners, ~icp~rsant opacifiers, hydrotropes, dyes, perfumes etc.
The following examples illustrate the invention. In the example the concentration of the peroxygen source is reported in terms of the starting concentration of aqueous hydrogen peroxide, to which other reactants are added. The molar concentration of the mixtures can be calculated.
Example 1 Reaction of TAED and 1.Yd~ G~en peroxide 1.1 This area of investigation was to find a simple method of determining the preC~nc~ of a stronger oYi~;~ing species than hydrogen peroxide. To this end a number of indicators containing oxidisable groups were tried, to identify which changed colour on addition of peracetic acid and the oxidising product of an embodiment of the invention, but not hydrogen peroxide. The results showed that alizarin complexone (AC) was decolourised by peracetic acid, but not WO94/18298 2 1 ~ 5 6 ~ 3 PCT/GB94/00229 .

by hyd~oyen peroxide. This material was therefore selected as the indicator of choice.
1.2 Once an indicator had been identified it was possible to carry out the experiments to see whether acid catalysed perhydrolysis was a possible me~-h~ism. TAED (22.8g - 0.lmol) was added to 60% hyd~yen peroxide (60mls lmol).
The mixture was stirred for 10 minutes. A 2ml aliquot was removed and added to alizarin complexone solution (0.5ml).
Over a period of a few minutes the colour in the solution was seen to disappear as the indicator was bleached.
1.3 The successful result of this experiment led to comparative bleaching experiments being carried out on stained swatches of cloth. The stains used were Red Wine, Tea and BCl (tea and clay). Comparisons were made between the bleaching performance of 60% H202, 10% peracetic acid PAAH and TAED/H202. The performance was assessed by measuring the initial brightness before washing and final brightness using a Hunterlab D25M colorimeter after the swatches had been rinsed and dried by application of an electric iron set at the wool setting. The results are given in Table 1.
1.4 Another set of experiments determined at which initial pH was the greatest bleaching observed. These experiments were carried out in 60ml 60% H202 with 22.8g TAED added.
The pH of the peroxide was adjusted before the addition of TAED with sodium hydroxide. The highest pH attainable was 6.95 as above this the decomposition of the peroxide was too rapid. The stain used in these tests were tea stains produced in house. These were selected as they showed the greatest residual colour in the previous tests. The pH of the solutions were measured initially after 1 hour's bleaching after 3h and finally after 24h. All bleaching experiments were carried out at room temperature. A blank was run using distilled water at pH 6. The results are shown in Tables 2 and 3.
1.5 Experiments were also carried out to identify whether Fe(III) ions had an effect on the bleaching properties.

WOg4/1~98 2~5 633 16 PCT/GB94/00~9 Three systems were set up, one cont~inin~ Dequest 2066 (an alkylene polyamine polylmethylene phosp~Qnic acid) as a sequestering agent, one with 0.5mls 20~M Fe(III) solution added and one with hydrG~en peroxide only. All of these S were carried out at pH 6. The results are shown in Table 3.
l.6 Results & ~iscussion All experiments carried out at room temperature in open beakers. Dwell time in the bath of l hour.

Table l Ex-mple St~in Red WIDC T
Ble ching Initi-lFID~I 1~1 Bd~ho~eu F~l Bri~h~
olution B~ightne~- Bnghtne--1.1 T~ED/~2O, ~65 74.8 2S.0 63.9 60%
1.1 H2Oz Comp 46 S 69.7 2S.8 46.6 comp 1.2 P~AH 46.S 76.7 2S.7 61.0 comp 1.3 HCI 46 S 63.9 - _ 2 0 con~o WO 94/18298 ~ 1 5 ~ PCT/GB94/00229 ~ o~
--l .C . .
~I ~ ~ 0 C~ ~ ~

t5`

~D
~D I

al ~ ,, ~ I

S ~
U) I
~1 O

.,1 ~ -.~ --I~1 H

~1 oN
_¦ cN
C.~ t~l C ,~ '~1 ~ N

E~ -- ~ o ~n --I O

a~

u) o ~n -_I .C . . . . . . . .
11$ 8~ Ul N tD ~ l ~ NU~ In I
., a~ ~ . . . . . . . .
Ul N N N N N ~ N N N N
H ~ ~

03 ~i co o o In er . . . .
N N N N N N ~
Ll N O O OtD O U~
a) .c ~~r~'~ N N1~ ~0 O ~1 ~ ~ .
.Y ~ 7 ~ N
E~
~ ~ ~ O ~1 ~ ~ 00 0 ~1 a) ~ . . . . . . .
_1 N N ~ ~ ~ ~ N ~ ~P
J~

11~ U) ~ I Oa~ O N ~1 0 :C HC

t~ H '~S
~ ~d~ ~ ~<1~dP H ~D
~rl O O O O O O O O t5~

~ a ,~ a ,~ a ,~ a ~ a ,~ a ,~ a ~ -- o ~n a --I o o o V C~

E~

WO94/18298 ~ C~ 3 PCT/GBg4loo~g ~ .

Notes:~With 60% hydrogen peroxide and TAED at the higher end of the acidic pH range ble~c~in~ was visible on contact, with the other solutions the bleaching was much less rapid. On reaction there was effervesc-ence visible as the TAED dissolved, this process was much more rapid at higher pH. There was a distinct odour of peracetic acid from all reactions cont~in;ng TAED. Remarkably the bleaching activity towards AC was still observed after 24 hours at room temperature.
1.7 These results show that TAED activates peroxide solutions at a range of pH's. The quickest bleaching performance is seen at higher pH probably due to more rapid dissolution of TAED and formation of stronger oxidising species under these conditions. The formation of an acidic species when TAED is dissolved in hydrogen peroxide is indicated by the pH change observed, the solutions only become markedly more acidic if TAED is present. Those experiments carried out without TAED show very little change in pH on the same time scale. The noticeable odour of peracetic acid, which is rather distinctive as well as pungent, is also evidence for the presence of this species in solution. It is assumed from this evidence that peracetic acid is likely to be the bleaching/oxidising species responsible for thelbleaching effect, although it may be a by-product, an intermediate or the product of further reaction of another oxidising species.
1.8 The experiments with and without Fe(III), at pH 6, showed very similar bleaching (the %ge stain loss was identical). This seems to show that iron catalysed radical reactions are not important under these conditions. This conclusion is borne out by the results with sequestrant present which gave very similar results to the experiment without sequestrant at pH 6.

21~33 ~

~x~m~le 2 TAE~ and ~ADHT as activators for peroxYgen bleaches at acidic ~H, for stains in solution and on fabrics 2.1 Experimental 2.1.1 Swatches The activator/peroxygen source combination procedure used was 60% hydrogen peroxide in a lO:l ratio with the activator. Small swatches of cloth (2O-25cm2) were used and the stain was chlorophyll. The bleaching experiments were run using lOmls hydrogen peroxide (60%) which was adjusted to the required pH using sodium hydroxide solution. A weighed quantity of the activator (16.7 mmol) was then added and the mixture stirred for 2 minutes to dissolve the activator. The swatch of cloth was then added and left for 30 minutes with occasional stirring. After 30 minutes, the swatches were removed from the activator solutions, rinsed with deioni e~ water to remove any remaining traces of bleach, dried by the techn;que used in example 1 and the brightness measured using a Hunterlab D25M colorimeter. The pH of the solution was measured after the cloths had been removed. The results are shown in Table 4.
2.1.2 The dependence of pH on time Experiments to monitor the relationship between pH and time were carried out using TAED and DADHT as activators.
The pH of 60% ~,~d~G~en peroxide was adjusted to about pH 6.
To 20mls of this solution was ~e~ 33m mols of activator.
The pH was measured with time.
2.1.3 Timed bleaching Timed bleaching experiments were carried out using the same t~chn;que and quantities as in Z.1.1 above with different dwell times of the swatch in the bleach solution.
Six separate solutions were prepared and a swatch added to each at the same time. The swatches were removed and 3~ rinsed in deio~ water after set time periods. The times used were Smins, lOmins, 2Omins, 3Omins, lhr and 2hrs. The final brightness after drying by the usual W094/18298 PCT/GB94/00~9 2 ~ 3 t~chn~que was determined using the Hunterlab. The results are shown in Table S.
2.1.4 Time/pH bleaching profile The solutions and swatches used were prepared as in the above experiments. Four solutions were prepared and a swatch added to each after a set period of time. The cloth was left in the bleach solution for 5mins and then removed and rinsed thoroughly with deionised water. The times at which the swatches were added were after lmin, 15mins, 30mins and lhr. A different solution was used for each swatch. The activators used were TAED and DADHT. The final brightness after drying of the cloth was measured using the Hunterlab. The results are shown in Table 7.
2.1.5 Activation of sodium perborate solutions in the presence of acidifying components.
Two lots of sodium perborate tetrahydrate (17.5g) mixed with citric acid (8g) (to reduce the pH on reaction with borate) were prepared. To one lot TAED (2.6g) was added. Each of the mixtures was added to 50mls deio~
water and stirred vigorously. The pH of the solutions was measured after dissolution had been achieved. The results are given in 2.2.6 below.
2.2 Results and Discussion 2.2.1 The chlorophyll stain was seen to be resilient to bleaching under these harsh conditions which makes it a very good stain to use. The less stain that is removed the better the comparisons which can be drawn between bleaches.
2.2.2 DADHT reacted faster than TAED, æee table 7. m e blank experiments with peracetic acid, water and hyd~Gyen peroxide (at both pH 6 and pH 1) show that activation is occurring, when the activator is present, and that this is not an effect of the lower pH in the activated solutions (Table 4). The drop in pH is good evidence that an acidic species is being produced which is not present in the unactivated peroxide solution.
2.2.3 The decrease in pH on addition of activator was seen to be rapid (Table 6). As would be expected the rate W094/18298 ~ r PCT/GB94/00~9 ?~5~ 22 varied with different activators due to differences in both the acid being proAllre~ and the rate of perhydrolysis.
2.2.4 The bleaching of swatches with different bleaching times showed the expected increase of bleaching with time (Table 5).
2.2.5 The effect of time and pH on the bleaching efficacy of activated solutions was also studied. In this case the dwell time in the bleaching solution was the same (5 mins) but the swatches were added after different times.
lo In four separate solutions cloth was added after lmin, 15mins, 3Omins and lhr. Each of these swatches was a quarter of the same larger swatch, to ensure a constant substrate concentration. After 5 minutes in the bleaching solution the cloth was removed and rinsed with deionised water. Comparing of the different swatches, for the same activator, gave a measure of the stability, rate of peracid release and pH dependence of the bleaching. The relationship between these variable is complex but qualitative comparisons can be made. The results show that TAED gives consistent bleaching over the first hour. DADHT
on the other hand gives better initial bleaching but after an hour the efficacy was similar (Table 7~. This seems to show that DADHT is perhydrolysed more rapidly initially but after time gives a similar conc~ntration of peracid. This is borne out by the pH measurements. The pH of the solution cont~i~ing DADHT decreased more rapidly than that of the TAED cont~;n;n~ solution. After 20hrs the figures were much closer (Table 6).
2.2.6 The activation of sodium perborate solutions was also seen to occur under acidic conditions. The use of citric acid and sodium dihydrogen phosphate enable acidic solutions of perborate to be prepared which also give rise to some degree of buffering. The pH of the solutions was seen to be acidic (pH 5.1) and much more stable than seen with more ro~entrated peroxide solutions. The pH of the activated and unactivated solutions was ~ery similar.

wo 94,l82g8 2 1 ~ 5 ~ 3 3 PCT/GB94/00~9 ..

Table 4. Activating acidic peroxide with different activators.
EDmplc ~ctiv~tot Initi-l pH F~lpN ~iti~l F~l 2.1 T~ED 6.00 2.47 14.26 38.4 (30min) 2.2 DADHT 6.00 233 14.26 613 2.1 CO~L, Blu~ 6.00 S.96 14.26 30.9 2.2 Comp Bl-n~ 7 S0 S.68 14.26 19.7 (~2) 2.3 Con4~ Bbn} - - 14.26 S9.2 ~A~
2.7 TAED 6.00 - 14.26 21.8 (lOmin) Table 5. The effect of different bleaching times on brightness and solution pH.

Time/ Final b-ightness pH aft~r 2 hr~
mins TAED DADHT TAED DADHT
27.8 48.8 3.21 3.15 33.5 57.4 3.09 3.15 46.2 60.6 3.20 3.17 52.2 68.2 3.15 3.15 57.1 79.8 3.18 3.21 120 74.1 84.5 3.21 3.14 W094/18298 ~ 15~ ~33 PCT/GB94/00~9 Table 6. The effect of activators on solution pH with time.

~me/
min~ p~
TAED DADRT
o 6.18 6.05 1 5.29 4.83 2 5.03 4.50 3 4.85 4.23 S 4.62 3.96 7 4.47 9 4.35

4.31 4.00 23 - 3.26 3.86 - 3.11 3.64 1200 3.27 2.54 Table 7. Bleaching efficiency against time.

Time/ Initial Final Brightre~
minq Brightnes~
TAED DADH~
1 14.26 32.0 34.1 14.26 31.9 32.7 14.26 28.7 26.9 14.26 25.8 20.9 DADHT - 1,5-diacetyl-2,4-diox~hPY~y~lo 1,3,5-triazine Example 3 Biocidal activity of activator/hYdroqen ~eroxide mixtures 3.1 The assessments were performed .in a test tube situation following the principles of BS 6471:1984.
3.2 lOOml volumes of Nutrient Broth were inoculated with Escherichia coli, StaPhylococcus aureus and SLLe~LOCOCCUS
faecalis.

wo 94,l82g8 2 I ~ ~ G 3 ~ PCT/GB94/00~9 3.3 A-150mg/1 solution of peracetic acid (PAA) was used for comparison. This was prepared in sterile distilled water.
3.4 In order to achieve co~centrations comparable with the comparative 150mg/1 PAA solution, test solutions of the formulations were prepared using TAED in the amount noted in the table below 0.0225g of TAED in lOOml 1% hydrogen peroxide solution. In example 3.6 the test solution was left to age for 24 hours before use. The other test lo solutions were used immediately.
3.5 lml of the test bacterial culture was added to 9ml of the appropriate formulation, mixed and left for 5 or 10 minutes at room temperature or at 40C (as indicated in the table).
3.6 lml of this liquor was transferred to 9ml of inactivator comprising 50g/1 sodium thiosulphate and 0.25g/1 catalase in distilled water. The inactivator was filter sterilised using 0.45~m membrane filters.
3.7 From these inactivated liquors, 10-fold serial dilutions were performed using Maximum Recovery Diluent (MRD). Pour plates were prepared using lml volumes of each dilution mixed with molten Plate Count Agar (PCA).
3.8 For controls the procP~l~re was repeated using 1%
hydrogen peroxide as the control for the two formulations and sterile distilled water as the control for PAA.
3.9 All plates were incubated for 48 hours at 37C after which time the number of colonies visible on each plate was counted. The reduction in the number of CFU compared to the control solution is calculated. The results quote the log (base 10) of the ~ ol count/test count. Where the figure is "more than" the actual figure quote this indicates the CFU count on the test plate was below the minimum which can be quantified by this te~h~ique.

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3.10 TAED/H2O2 generally did not ~pp~r to be part~ rly effective when compared with PAA at room temperature for short contact times although some reduction was seen against ~.coli and ~taph. aureus.
3.11 Increasing the temperature to 40C improved the performance of TAED.
3.12 Increasing the contact time from 5 minutes to lO
minutres and so im~Loved the results.
3.13 By aging the solution for 24 hours before use the same improvement was seen as by increasing the temperature.
This improvement may be a result of the slow release properties of the system.
Example 4 Production of Acidic Percarbonate solutions 4.1 It has been found that citric acid and sodium dihydrogen phosphate are able to produce acidic solutions of hydrogen peroxide when mixed with sodium perborate and water. This experiment was designed to test whether the same was true for sodium percarbonate.
4.2 The following formulations were added to 1~ cold water. In each case 1.85 g TAED, as activator was included. The amount of percarbonate was varied, with the amount of citric acid added being such as to give approximately the same pH in each test. The presence of hydloyen peroxide was determined by iodometric titration as described in Example 5 below.

W094/18298 PCT/GB94/00~9 6~3 28 Sodium 2.05 4.13 8.20 Percarbonate g Citric Acid g 1.54 3.08 6.04 5Time mins Iodometric Titrations 0.5 0.7 1.
1.2 2.35 4.3 2.9 6.80 9.9

5.4 12.05 14.9 17.5 17.80 21.7 ph at 10 mins 6.39 6.38 6.35 Example 5 Acids and anhydrides as activaters 5.1 Using acetic acid (comparative) and TAED (invention) as the acetyl donor.
The following experiments were carried out using 50ml 10% w/v hydrogen peroxide at room temperature with activator and compared against controls. Chlorophyll stained swatches were used as the substrate. Reflectance was measured using an ICS Texicon Spectra Flash 500 (a colorimeter using the cT~r.~R system) using software version 4.70.
The initial pH's of these solutions were recorded.
The swatches were left in solution for 75 minutes.
The brightness was compared to an unbleached chlorophyll stained swatch after rinsing with deionised water and drying as in the previous examples.

W094/18298 PCT/GB94/00~9 Results Table 10 Example R--~i ng Solution Activator Initial, pH
5.1.1 1.6 50 ml H~ TAED 3.17g 3.35 lighter 5.1.2 Comp O.35 50 ml H~ Glacial 2.32 lighter Acet c 5.1.3 Comp 0.75 50 ml H~ _ 3.33 lighter 5.1.4 Comp 0.2 darker 50 ml H~ Glacial 2.62 Acetic 1.67g lo It can be seen that acetic acid is ineffective as an activator under these conditions. This experiment also shows that the bleaching effect of TAED does not arise from hydrolysis followed by perhydrolysis of the resulting acetic acid.
5.2 The use of acetic anhvdride (com~arative) and TAED
(inventive) Acetic anhydride is a widely used source of peracids under laboratory conditions. This material is however water sensitive, corrosive and therefore not easy to handle. The following experiments were designed to see how effective acetic anhydride was as a peracid generator under dilute aqueous conditions.
The procedure used was similar to that in the above experiments (5.1) with acetic acid. Hydrogen peroxide was used at lO~. A range of stained swatches were used, these were chlorophyll, curry and blackberry. Samples were also assayed for peracetic acid using an iodometric titration.
5.2.1 Bleaching stained swatches In the following experiments the peroxide/activator combinations shown in Table 10 were used to prepare the bleaching solutions.
All experiments were carried out at ambient temr~rature. Formulation 5.2.4 Comparative was only used WO94/18298 2 ~ ~ ~ PCT/GB94/00229 in the first two experiments. The reflectance was mea~ured as in 5.1. In the table the reflectance differences are noted. A positive value means the bleach~d swatch i8 lighter than the cGllL~ol st~in~ swatch and a negative ~ign means it is darker.
~xperimQnt A
Chlorophyll stained swatches were added to these solutions and left to bleach for 75 minsO After this time the swatches were removed and washed in water to remove any remaining active species.
Exp~riment B
Chlorophyll stained swatches were added to the solutions used above and left to bleach overnight for 17 hours. The swatches were rinsed. The pH of the bleaching solution was measured after the cloths had been removed.
Experiment ~
Fresh solutions using the first three compositions were prepared and allowed to stand overnight before chlorophyll st~ swatches were added. The cloths were left to bleach for 75 mins and then removed and rinsed.
Experiment D
This was the same as experiment A but using curry stained swatches. There was no water/acetic anhydride solution (S.2.4 comp) tested.
~xperiment ~
This was the same as experiment A using blackberry stained swatches. There was no water/acetic anhydride solution (5.2.4 comp) tested.
5.2.2 Iodometric titration The solutions 5.2.1 and 5.2.2 (comp) used in experiment E were tested after given time intervals for peracetic concentration using an iodometric titration on ice so that hydrogen peroxide gives minimal values alone) the titration being carried out as soon as possible after the titration mixture is made up.

WO94/18298 2 1~ ~ 6 3 ~ PCT/GB94/00229 5.2.3 ~ Results Table11 E~ Solution Activator pH n~lG~li./e Ditf~ ce A B C D E
5.2.1 50ml 3.17~ 3.47 1.3 4.4 0.38 1.3 8.6 5.2.2 Comp 50ml 2.49 2.10 3.2 8.6 1.6 1.3 10.
H202 acetic 2 anhydride 5.2.3 Comp 50ml - 3.69 0.6 1.0 0.67 1.2 8.2 5.2.4 Comp 50ml 2.49 - 0.4 H20 acetic 8 0.4 anhydride In general acetic anhydride/H2O2 reacted more quickly than either TAED/H2O2 or H2O2 itself. TAED/H2O2 gave better ~` bleaching against chlorophyll stains than H2O2 alone.
s.3 Determination of the peracetic acid produced bY acetic anhydride (comparative) and TAED.
The relative concentration of oxidising agent was determined at time intervals using an iodometric titration on ice. The solutions studied were those used in experiments 5.2.1 and 5.2.2 Comp Experiment E as 5.3.1 and 5.3.2, respectively. The iodometric titration carried out was that used for calibrating peracetic acid. The solution to be assayed is added to a flask cont~ining potassium iodide, acetic acid and ice. The iodine liberated is titrated with sodium thiosulphate.

WO94/18298~15 g~33 32 PCT/GB94/00~9 T~hle 1~
Relative amount of ~o~.
Time/hrOxidising agent 5.3.1 (TAED) 5.3.2 (acetic anhydride) r 1.5 0.19 1.16 3.75 0.23 1.37 20.75 0.61 1.56 26 0.70 1.43 92 0.72 0.91 117 0.91 0.76 168 1.22 0.57 It can be seen from the above results that the TAED
activated solution gives a lower initial co~c~tration of strong oxidising agent. However over time, in this case 7 days, the TAED solution increases in ~L~ oxidising agent concentration while the acetic anhydride solution loses peracid. After several days the levels of strong oxidising agent acid are higher in the TAED cont~; n ing solution.
There is still a large volume of TAED left l7n~ colved after about 140 hrs. This makes this a very good slow release procedure.
Example 6 Perborate/TAED in a nor, ~factant containinq com~osition A mixture of the following powders was made and added to lL of water:
1.8 g TAED
2.58 g sodium perborate monohydrate without or with 1.58 g æodium bicarbonate varying amounts of citric acid or sodium dihydLoyen orthophosphate as acidifiers. The pH of the solution at the varying amounts of acid component were measured after 10 mins. The results are shown in the following table.

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In o WO94/18298 2 1 ~ l PCT/GB94/00~9 The bleaching performance of some of the solutions was determined on un-glazed, tea-st~ne~ tiles. The bleaching solution is applied to one half of the tile and the difference in whit~n~ss, as determined using a Hunter-Lab apparatus between the two halves is determined. The value is given as ~W. The Hunter-Lab apparatus is set to CIE
tristimulus XYZ scale. The W reading is the Z% brightness.
The solution as above with bicarbonate, which had a pH
of 6.3 gave a ~W value of 5.5.
Example 7 Surfactant - 3 Co...~ositions Including Perborate and Various Activators Mixtures containing 2.58 g sodium perborate monohydrate, 3 g citric acid, 1.6 g sodium bicarbonate and activator comprising 1.8 g TAED or an equivalent weight of N-benzyl caprolactam (NBC) or triacetyl ethanolamine (TAE) or granules cont~;n;ng TAED, were dissolved into le water.
The peracid release rate was monitored using an iodometric titration on ice, as above. The results are given in the following table.

Oxidisin~ agent a~ount for the followin~ activators Time TAED TAE NBC Granule 1 Granule 2 0.7 0.4 0.45 0.4 0.75 25 15 1.9 0.3 0.85 1.6 1.0 4.1 0.25 0.7 4.3 2.5 8.1 0.35 1.2 8.1 4.5 11.4 0.45 1.8 12.2 6.7 1 DAY 20 0.5 8.0 11.6* 18.8 ~ RESULT ~FTER 3 DAYS
Granule 1 is Mykon ATC (available from the applicant company) formed from 90-94% TAED carboxymethyl cellulose binder and no more than 2~ water and has particle size 95 in the range 0.2 to 1.6 mm.
Granule 2 is Mykon ASD formed from 83 TO 87% TAED, CMC
binder and 2.5 to 3.5% methylene phosphonic acid 215~3~

sequestrant and no more than 2.5% water having particle size 95% in the range 0.2 to 1.6 mm.
The temperature during the reaction was 40~C
~xample 8 Storage Stability of ~ompositions Containina Surfactants The following compositions were formulated by blending the ingredients in particulate form and storing them in a closed container at ambient temperature. The amount of available oxygen after 12 weeks of storage was determined by standard Avox titration. The percentage loss of available oxygen is reported in the following table.

Example No. 8.1 8.2 Linear alkyl benzene sulphonate 9~ 9%
TAED 3% 3%
Coconut diethanolamide 3% 3%
STPP 20% 20%
C.~tC alcohol-7ethoxylate 3.4% 3.4%
Citric Acid 6S 10%
Sodium perborate monohydrate 5% 5%
Sodium Sulphate to 100% to 100%
Loss of Avox 6.2~ 13.4%

Example 9 Oxidisinq Agent Concentration for Various Activators at pH

6.3 Mixtures comprising 2.58 g sodium perborate monohydrate, 1.58 g sodium bicarbonate and 2.1 g sodium dihydrogen orthophosphate and 1.88 g of activator, and dissolved into 2 litres of water. The ~on~ntration of strong oxidising agent in the solution generated was measured after various periods of time using the iodometric titration mentioned above. The results are given in the following table.

a~ 3 36 T~RT-~ 16 Amount of oxidi~ing agent for diff~r~nt activator~
Time TAE TAED t 5 min 0.4S .6 15 min 0.25 1.7 30 min 0.4 3.6 45 min 0.4 S.l 1 hr 0.35 6.3 1 day 0.4 10.6 These results show that TAED gives excellent long term release of strong oxidising agent, continuing to increase even after one hour.
.
ExamPle lo A solution of Flash liquid and a similar solution, but with an added amount of bleach booster mixture formed from TAED (at 1.88 g/e),-sodium perborate monohydrate (at 2.58 g/~) and citric acid in an amount to give a final pH of 6.5, were compared for their performance in bleaching tea stains. The solutions were applied with a brush to half a stained tile and then either dipped in water or wiped with a cloth to remove the liquid. The whiteness was then recorded as described above. The ~W values for Flash alone, removed by wiping and dipping, were 4.0 and 9.7, respectively. The ~W values for the boosted Flash were 4.8 and 13. 5 respectively.

Claims (20)

1. A process in which a peroxygen source is reacted with an activator compound which is an N-acyl compound having at least two carbon atoms in the acyl group in a first step in aqueous solution under acidic conditions to form an oxidising product, which is a stronger oxidising agent than the peroxygen source.

2. A process according to claim 1 in which the activator compound has the formula I

in which R1 is an alkyl, alkenyl, aralkyl, alkaryl or aryl group, any of which groups has up to 24 carbon atoms and may be substituted or unsubstituted, and -NR2R3 is a leaving group in which R2 and R3 are independently selected from H, C1-24-alkyl, -alkenyl, -aralkyl, alkaryl or -aryl groups, and carbonyl-containing moieties having at least 2 carbon atoms in which the carbonyl group is joined to the nitrogen atom in the formula I, in which R2 and R3 can be joined together as a cyclic group and/or R1 can be joined to either R2 or R3 to form a cyclic group.

3. A process according to claim 2 in which R1 is an aliphatic group, preferably a C1-18-alkyl, or -alkenyl group, or is an aryl group.

4. A process according to any preceding claim in which the product containing stronger bleaching species is subsequently used as a bleaching and/or disinfecting agent in an aqueous environment at a pH of less than 7.

5. A process according to any preceding claim in which the product of the first step is subsequently used as an oxidising agent in an oxidising step which is carried out without removal of any by-products from the first step.

6. A process according to any preceding claim in which the peroxygen source is selected from hydrogen peroxide, organic peroxides and inorganic persalts.

7. A process according to any preceding claim in which the pH in the first step is less than 6.5 at the beginning of the reaction, and is preferably more than 2.0, more preferably more than 5Ø

8. A process according to any preceding claim in which the concentration of the peroxygen source in the reaction mixture of the first step is less than 10M preferably less than 5M, more preferably less than 2M, and is preferably at least 0.01M, even more preferably less than 1M and at least 0.05M, especially at least 0.1M.

9. A process according to any preceding claim in which the temperature in the first step of the reaction is in the range 0 to 95°, preferably at least 20°C and up to 80°C, more preferably up to 60°C.

10. Use of a composite product comprising a peroxygen source and an N-acyl activator compound having at least two carbon atoms in the acyl group and, if necessary, an acidifying component capable of rendering an aqueous solution of the peroxygen source and activator compound acidic to form the reactant mixture for the first step of a process according to any preceding claim, by adding the product to water to dissolve the peroxygen source, the activator and the acidifying component to form an acidic solution.

11. Use according to claim 10 in which in the product the activator compound is present in an amount sufficient to provide 0.1 to 5 equivalents acyl groups per mole peroxygen source preferably up to 1.0 equivalents.

12. A use according to claim 10 or 11 in which the acidifying component is present in the product in an amount such that when the components of the product are dissolved in aqueous solution with the peroxygen source being at a concentration in the range 0.01 to 10M (preferably in the range 0.1 to 1.0M) the pH is less than 6.5.

13. A use according to any of claims 10 to 12 in which the activator compound is as defined in claim 2 or claim 3.

14. A use according to any of claims 10 to 13 in which the peroxygen source is selected from hydrogen peroxide, organic peroxides and inorganic persalts.

15. A use according to any of claims 11 to 14 in which the composite product includes a surfactant.

16. Use according to any of claims 10 to 15 in which the aqueous product is used as an oxidising agent, preferably as a bleaching and/or disinfecting agent.

17. A product containing in the same composition a peroxygen source, an N-acyl activator compound having at least two carbon atoms in the N-acyl group, a surfactant and, if necessary, an acidifying component, such that the product dissolves into water to form an acidic solution of peroxygen source, activator, acidifying component, if any, and surfactant.

18. Use of an aqueous solution of a product according to claim 17 as an oxidising agent, preferably as a bleaching and/or disinfecting agent.

19. A process in which a composite product as defined in any of claims 10 to 16 or a product according to claim 17 or claim 18 is diluted with water to form an acidic solution.

20. A process according to claim 19 in which the aqueous solution thereby formed is used as a bleaching agent, disinfectant, sterilising agent or biocide, the pH
remaining at less than 7 during the use of the solution.