WO1995020876A1

WO1995020876A1 - Oxidising compositions

Info

Publication number: WO1995020876A1
Application number: PCT/GB1995/000248
Authority: WO
Inventors: Vincent Brian Croud; Stephen James Tompsett
Original assignee: Warwick International Group Limited
Priority date: 1994-02-07
Filing date: 1995-02-07
Publication date: 1995-08-10
Also published as: AU1584495A

Abstract

The use of n-acyl and o-acyl bleach activator compounds to generate peroxy acids in aqueous acidic environments and their subsequent use as a viricide. Preferably during the reaction a viricide or acid is also present. Preferred processes use hydrogen peroxide with tetraacetylethylene diamine or with the sodium salt of nonoaryloxybenzene sulphonate.

Description

OXIDISING COMPOSITIONS This invention relates to compositions which are viricidally ^" active processes for preparing such compositions and uses of such compositions. The viruses to be protected against or killed using the viricidal compositions of this invention may be any virus, but in particular this invention relates to viricidal compositions for killing and/or protecting against diseases which affect birds and animals, in particular for use in agricultural applications. Thus, the present invention is especially useful for prevention, protection against and/or eradication of diseases such as foot and mouth disease, swine vesicular disease, fowl pest and tuberculosis.

Many viricidal compositions are known for protection against or eradication of such diseases and have been approved by the Ministry of Agriculture, Fisheries and Food for use as viricidal disinfectants when an order is placed on livestock when an outbreak of a disease has occurred. Citric acid, sulphamic acid and peracetic acid are examples. The citric and sulphamic acid viricides are approved for use in respect of foot and mouth disease and the peracetic acid-based viricides are approved for use in respect of both foot and mouth disease and in addition many other bird and animal diseases. Peracids are however unstable and can be dangerous to transport in bulk.

It is known to prepare peracids in situ from either acetic acid or acetic anhydride with hydrogen peroxide. However, the in situ reaction using acetic acid is problematic because water must be removed to drive the reaction or else a large excess of one of the reactants must be used which necessitates complex separation and recycling steps. Both acetic acid and acetic anhydride as starting materials for such an in situ reaction require special precautions for handling and so are not desirable. They are therefore impractical for use in farming applications. Acetic anhydride is water sensitive and so requires special storage conditions.

It would be desirable to provide a viricidal process and composition which could be used in such a process against a wide range of viruses, including bird and animal diseases, especially for agricultural applications and which could receive MAFF approval, and at the same time which would overcome the handling difficulties of the known peracetic acid compositions. In accordance with the present invention there is provided a process comprising reacting a peroxygen source with an activator compound which is an acyl donor in a first step in aqueous solution at a pH below pK_a(l) where pK_a(l) is the pK_a of the percarboxylic acid corresponding to the acyl group of the activator, to form a product solution comprising an oxidising product which is a stronger oxidising agent than the peroxygen source and subsequently using the product solution as a viricidal composition at a pH below pK_a(l) in a second viricidal use step. Preferably the product solution also comprises a viricidal acid and most preferably the viricidal acid is present in a viricidally effective amount.

Preferably, at least a portion of the viricidal acid is present in the aqueous solution during the reaction between the peroxygen source and the activator compound of the first step. The viricidal acid is therefore preferably used both as a viricidal agent and a pH-modifying agent and is preferably the sole pH modifying agent to ensure that the reaction in the first step takes place at a pH below pK_a(l).

The viricidal acid which may be used in the composition may be any acid having viricidal properties. Particularly preferred are sulphamic and citric acids. Sulphamic acid is particularly preferred. The concentration of the viricidal acid at least during the second step is preferably a viricidally effective amount. Most preferably, all of the required viricidal acid, sufficient to provide a viricidally effective amount during the second step will also be present during the first step in the process. If necessary an additional pH-modifying component may be included, however, preferably the viricidal acid is the only pH-modifying component in the reactant mixture and the product solution.

The concentration of viricidal acid will depend upon the type of viricidal acid used and in addition will depend upon the type of virus to be eradicated or protected against. The concentration will generally be from 0.005% by weight to 10% by weight of the product solution. Generally the product solution will contain at least 0.01% by weight and for example up to 5% by weight, preferably no greater than 1% by weight viricidal acid, in use.

The activator may be an N-acyl or an O-acyl derivative. Preferably the activator is a compound of the formula I

in which L is a leaving group attached via an oxygen or a nitrogen atom to the C=0 carbon atom and R is an alkyl, aralkyl, alkaryl, or aryl group, any of which groups has up to 24 carbon atoms and may be substituted or unsubstituted.

The leaving group L is preferably a compound the conjugate acid of which has a pKa in the range 4 to 13, preferably 7 to 11, most preferably 8 to 11. It is preferred that R is an aliphatic group preferably a C,.^ alkyl group, or an aryl group.

In the present invention the term alkyl includes alkenyl and alkyl groups may be straight, branched or cyclic. In the formula I L and R may be joined to form a cyclic compound, usually a lactone or a lactam. 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. L can itself comprise a cyclic group, including heterocyclic groups, for instance joined to the C=0 group of the compound I via the heteroatom.

Substituents on R and L can include hydroxyl,

2 , ? .

=N-R in which R is selected from any of the groups represented by 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 can be any N-acyl or O-acyl acyl-donor compound, which has been described as a bleach activator for use in laundry detergents. The compound of the formula I may be an anhydride, but is preferably an ester or, even more preferably, an amide derivative. Preferably the activator is a solid at room temperature. Preferred N-acyl compounds are those having at least two carbon atoms in the acyl group preferably having the formula I

in which R¹ is an alkyl, alkenyl, alkenyl, aralkyl, alkaryl or aryl group, any of which groups has up to 24 carbon 3 atoms and may be substituted or unsubstituted, and -NR R is a leaving group in which R and R are independently selected from H, C-,.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 R and R can be joined together as a cyclic group and/or R can be joined to either R or R to form a cyclic group. Preferred O-acyl compounds are esters of a C₂ or higher carboxylic acid preferably having the formula II

O RiCllOR2 I in which R is a alkyl, alkenyl, alkenyl, aralkyl, alkaryl or aryl group, any of which groups has up to 24 carbon atoms and may be substituted or unsubstituted, and R 2 is selected from C₁.₂₄-alkyl, -alkenyl, -aralkyl, -alkaryl and -aryl groups, any of which are substituted or unsubstituted, R and R optionally being joined to form a cyclic group.

Amide derivatives include acyl i idazolides and N,N-di acylamides, such as TAED. Other examples of N-acyl derivatives are: a) l,5-diacetyl-2, 4-dioxohexahydro-l,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; d) 0,N,N-trisubstituted hydroxylamines, such as O-benzoyl- N,N-succinyl hydroxylamine, 0-p-nitrobenzoyl-N,N-succinyl hydroxylamine and 0,N,N-triacetyl hydroxylamine; e) N,N'-diacyl sulphurylamides, for example N,N'-dimethyl- N,N'-dimethyl-N,N'-diacetyl sulphury1 amide and N,N'- diethy1-N,N'-dipropiony1 sulphurylamide; f) l,3-diacyl-4,5-diacyloxy-imidazolines, for example 1,3- diformyl-4,5-diacetoxy imidazoline, l,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 the tetraacetyl or tetrapropionyl propylene diurea and their dimethyl derivatives; j) Alpha-acyloxy-(N,N')polyacyl malona ides, such as alpha-acetoxy-(N,N')-diacety1 malonamide. k) 0,N,N-trisubstituted alkanolamines, such as 0,N,N- triacetyl ethanolamine. k') Cyanamides, such as those disclosed in DE-A-3,304,848.

1) N-acyl lactams, such as N-benzoyl-caprolactam,

N-acetyl caprolactam, the analogous compounds formed from

C₄.₁₀ lactams. m) N-acyl and N-alkyl derivatives of substituted or unsubstituted succinimide, phthalimide and of imides of other dibasic carboxylic acids, having 5 or more carbon atoms in the imide ring.

Alternatively the compound may be an ester, for instance n) sugar esters, such as pentaacetylglucose, o) esters of imidic acids such as ethyl benzi idate, p) triacylcyanurates, such as triacetylcyanurate and tribenzoylcyanurate, q) esters giving relatively surface active oxidising products for instance of C₈.₁₈-alkanoic or -aralkanoic acids such as described in GB-A-864798, GB-A-1147871 and the esters described in EP-A-98129 and EP-A-106634, for instance compounds of the formula I where L comprises an aryl group having a sulphonic acid group (optionally salified) substituted in the ring to confer water solubility on a benzyl group, especially nonanoyloxy- benzenesulphonate sodium salt (NOBS) , isononanoyloxy- benzenesulphonate sodium salt (ISONOBS) and benzoyloxy- benzenesulphonate sodium salt (BOBS) r) phenyl esters of C₁₄.₂₂-alkanoic or -alkenoic acids, s) esters of hydroxylamine, t) ge inal diesters of lower alkanoic acids and ge -diols, such as those described in EP-A-0125781 especially 1,1,5- triacetoxypent-4-ene and 1,1,5,5-tetraacetoxypentane and the corresponding butene and butane compounds, ethylidene benzoate acetate and bis(ethylidene acetate) adipate and u) enol esters, for instance as described in EP-A-0140648 and EP-A-0092932.

Where the activator is an anhydride it is preferably a solid material, and is preferably an intra-molecular anhydride, or a polyacid polyanhydride. Such anhydride compounds are more storage stable than liquid anhydrides, such as acetic anhydride. Anhydride derivatives which may be used as activator include v) intramolecular anhydrides of dibasic carboxylic acids, for instance succinic, maleic, adipic, phthalic or 5- norbornene-2,3-dicarboxylic anhydride, w) intermolecular anhydrides, including mixed anhydrides, of mono- poly-basic carboxylic acids, such as diacetic anhydride of isophthalic or perphthalic acid x) isatoic anhydride or related compounds such as described in WO-A-8907640 having the generic formula II

wherein Q is a divalent organic group such that Q and N together with the carbonyl groups and oxygen atom of the anhydride group form one or more cyclic structures and R is H, alkyl, aryl, halogen or a carbonyl group of a carboxyl containing function; or benzoxazin-4-ones as described in WO-A-8907639, that is compounds of the formula III

wherein Q' is selected from the same groups as Q and R ,3^J is H, alkyl, aryl, alkaryl, aralkyl, alkoxyl,. haloalkyl, amino, aminoalkyl, carboxylic group or a carbonyl- containing function; preferably 2-methyl-(4H)3,1- benzoxazin-4-one (2MB4) or 2-phenyl-(4H)3,l-benzoxazin-4- one (2PB4) ; y) polymeric anhydrides such as poly(adipic) anhydride or other compounds described in our co-pending application WO- A-9306203.

The peroxygen source may be hydrogen peroxide itself, or 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. Mixtures of any of these peroxygen sources may also be used. Particularly preferred peroxygen sources are sodium perborate, sodium percarbonate and Caro's acid or salts thereof.

In the perhydrolysis reaction the amount of water present is preferably at least as much (in terms of moles) as the peroxygen 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 hydrogen 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 or less than 5% w/v. The concentration is usually at least 0.01%, preferably at least 0.1% or even preferably at least 0.2% w/v, more preferably at least 1% 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 concentrations of hydrogen peroxide. In use, the concentration of peroxygen source in the product solution is for instance less than 10M or even less than 5M, preferably less than 2M or sometimes even less than 1M down to 0.01M. Preferably the concentration is at least 0.01M, more preferably 0.1M, even more preferably at least 0.2M. The pH in the second, viricidal use step is usually less than 8.0, preferably less than 7.0, or even less than 6.0. The pH is usually more than 2.0, for instance more than 3.0, most preferably more than 5.0. In the- perhydrolysis step of the reaction the temperature is preferably in the range 0 to 95°C, more preferably in the range 10 to 80°C. The invention is most useful when the temperature is less than 60°C, or even less than 50°C, for instance less than 40°C or even around room temperature. The temperature is often above 20°C. The temperature in any subsequent use step is likely to be somewhat lower than the temperature in the first step, due to cooling on application. Preferred temperatures for the second, viricidal step are 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. 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 at temperatures around ambient and less than hand hot which is advantageous from a safety point of view. Also the rate of perhydrolysis reaction can be controlled by adjusting the temperature. In the process of the invention it is possible for the first step to be carried out having a time delay before the second step. For instance the peroxygen source and the bleach activator may be allowed to react in aqueous conditions for at least five minutes, up to one or two days, suitably in the range ten minutes to one day before the aqueous reaction product of the first step is used as a viricidal composition. Such a time delay may be preferred to ensure that the perhydrolysis reaction is substantially complete before the second step. The peroxygen source, bleach activator and preferably also the viricidal acid may be mixed together and added to water simultaneously, or alternatively they may be added to water one after the other or in various combinations. They may be added to water and used immediately.

The second step in accordance with the process of the present invention in which the product solution is used as a viricidal" composition comprises application of the solution to surfaces for instance floors, walls of buildings, stores, gates and fences or for use in foot/hoof baths, wheel-baths for use on farms and for any other application. Preferably, the compositions should be applied to a clean surface, after ensuring that dung, litter etc is removed and disposed of. The cleaned area is subsequently contacted by washing, spraying or by any other means of contacting with the composition formed in the first steps of the present invention. Preferably in the second step, the product solution may be used to kill or protect against viruses which affect animals and/or birds. Examples include:- (i) foul pest; (ii) swine vesicular disease; (iϋ) foot and mouth diseases; (iv) tuberculosis. It is postulated that the present invention is particularly advantageous because the oxidising product which is a stronger oxidising agent than the peroxygen source is a relatively short lived but highly effective viricidal agent. When used in the preferred composition, in combination with the viricidal acid it is postulated that viricidal acid produces more long term viricidal properties and the two used in combination, provide a synergistic viricidal effect.

The present invention also provides a viricidal composition comprising a peroxygen source, an activator which is an acyl donor and a viricidally effective amount of a viricidal acid such that when the composition is added to water the pH is reduced to and remains below pK_a(l) (as defined above) , preferably below pH 7 and a new use of such a composition to provide viricidal properties. The viricidal composition may contain a pH-adjusting component. However preferably, the viricidal acid alone provides the required pH.

Where an additional acidifying component is used, it may be an acid and/or buffering material. The component may comprise a polybasic organic acid, such as a polybasic carboxylic acid such as succinic or adipic acid, in addition to citric and/or sulphamic acid. Alternatively the component may react with a by-product of the perhydrolysis reaction to increase the acidity in use. Where perborate is used, borate is a by-product and so any component known to react with borate to drop the pH, e.g. cis-l,2-diols, such as glycols and polyols, boric acid or sodium dihydrogen phosphate can be used. Acidifying components may also be used where percarbonate is the peroxygen source.

In one preferred embodiment of the oxidising composition the activator is TAED. The peroxygen source may be hydrogen peroxide or a solid peroxygen compound. In another preferred embodiment of the oxidising composition, the activator is any other activator which is solid at ambient temperatures.

Although the oxidising composition for use in the present invention may contain the individual components each in separate compositions, for instance one of which contains the peroxygen source, another of which contains the activator and another of which contains the viricidal acid, it is preferred to provide at least the activator and viricidal acid as a mixture in a single composition in a form in which they are stable. Such a composition which does not contain peroxygen source, may, for instance, be added to an aqueous solution of peroxgyen source such as aqueous hydrogen peroxide, which is readily commercially available, in the form of, for instance 60%, 20%, 10% or, preferably, 5% w/v or less solution. It is most preferred for all of the components to be provided in a single composition, in which the components do not react, and which is preferably therefore substantially water-free.

The compositions 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 activator with protective coatings, for instance produced by microencapsulation techniques 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 or diluted in to water or with abrasion.

Preferably the oxidising composition is in a 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 components. Such particles may be provided by techniques similar to those used in the laundry detergent industry, for instance including particles produced by spray drying liquid slurries, by granulation techniques using binders (for instance synthetic or natural polymers or derivatives) or by melt blending followed by extrusion or other techniques.

Preferably the product contains the active ingredients in appropriate relative quantities so that when the composition is diluted (or the compositions are mixed) with water the first step of the reaction proceeds at the optimal rate and at the desired pH. The activator and peroxygen source are for instance present in relative amounts such that up to 150%, preferably up to 100%, or most preferably up to 80% of the stoichiometric amount of activator (for complete reaction with the peroxygen source) is provided. Preferably the amount of activator is at least 5%, preferably at least 10%, most preferably at least

20% of the stoichiometric amount of the activator.

The product solution may require surface active properties. Where they are required, the product solution may comprise a surfactant. Any conventional surfactant may be used, selected from non-ionic, anionic, cationic, and amphoteric surfactants. However, non-ionic and amphoteric surfactants are preferred as they are more resistant to changing conditions of pH. Suitable nonionic surfactants include for example alkanolamides (such as CIO to C20) and/or ethoxylated alcohols, carboxylic acids, amines, alcohol amides, alcohol phenol, glyceryl esters, sorbitan esters, phosphate esters etc. Suitable amphoteric surfactants include for example betaines, such as alkyl betaines, sulphobetaines, and also imidazoline derivatives.

Suitable cationic surfactants include for example quaternary amines, imidizolines and quaternised imidizolines.

Suitable anionic surfactants include any surfactant useful in a detergent for example salts of sulphonic or monoesterified sulphuric acids, fatty alkyl ether sulphosuccinates, acyl sarcosinates, acyl taurides and paraffin sulphonates. The preferred anionic surfactants are salts of alkali metals or alkaline earth metals, preferably sodium.

Where the oxidising composition comprises surfactant(s) it is preferably incorporated in amounts no greater than 5% by weight surfactant, most preferably no greater than 3% by weight surfactant, based on the total weight of the viricidal oxidising composition.

The compositions of the present invention preferably also include a chelating agent. One or mixtures of more than one chelating agent can be used. Particularly preferred chelating agents are EDTA, DTPA and phosphonates.

Where chelating agents are incorporated, they are generally at a concentration in the product solution of at least 0.001% by weight, preferably at least 0.01% and no greater than 10%, preferably no greater than 1% by weight. The oxidising composition may include other additives, for instance stabilisers which stabilise the product before use, as well as stabilisers for the peroxy acid oxidising species formed in the reaction, such as any heavy metal sequestrant. In addition to the surfactants mentioned above, inorganic salts, for instance which affect the physical properties of the solid form or act as diluent may also be incorporated. Other ingredients may be included depending upon for example the mode of use of the composition. Examples are perfumes, or agents to assist dissolution or dispersion of the product into water or inorganic or enzymatic catalysts.

The viricidal oxidising compositions of the present invention may be provided in a form which is suitable to be diluted directly into water to allow the first and second steps of the reaction to proceed without further additions. The viricidal oxidising compositions of the present invention may be either solid or liquid. For example, they may be pourable liquids which are aqueous or non-aqueous, or may be in any other form. Preferably, the compositions are either solid or a pourable liquid. Thickeners may be included to increase viscosity, such as those which are well known in the art, including gums, electrolytes (in combination with surfactant) , urea, triethanolamine and polyacrylates.

The oxidising compositions for use in the present invention are preferably low foaming and therefore, if surfactant is included de-foaming agents may be incorporated, such as soap or silicone anti-foams.

The solid oxidising compositions according to the invention are particularly preferred because they have good storage stability since in general it is easier to keep the bleach activator and peroxygen donor compound in separate particles, and is easier to isolate other components of the composition from one another and from the bleach components.

In the solid compositions, one or more of the components may be in a granular form and these granules may include agents to increase the rate of dissolution of the compositions upon addition to water. Such dissolution rate enhancers may create effervescence, for instance, a suitable component may be sodium bicarbonate or other alkaline metal bicarbonates. The following examples illustrate the invention. In the examples, the concentration of peroxygen source is reported in terms of the starting concentration of aqueous hydrogen peroxide, to which other reactants are added. The molar concentration can be calculated.

Example 1

Perborate/TAED/Citric Acid in a Non-Surfactant-Containinq

Composition

A viricidal composition was prepared by first preparing a mixture of the following powders and adding to

1£ of water:

1.8 g TAED

2.58 g sodium perborate monohydrate without or with 1.58 g sodium bicarbonate varying amounts of citric acid as acidifier and co- viricide. 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 1.

TABLE 1

PH

Acidifer Bicarbonate Citric Acid(g)

1 2 3 4 5 6 7 8 9 10

Citric Yes 8.6 7.2 6.0 5.4 4.9 4.8 4.4 4.3 4.0 3.9 Acid

10 Citric Acid No 8.5 6.5 5.1 4.6 4.3 4.1 3.9 3.6 3.5 3.5

Example 2

Compositions Containing Surfactant and Perborate and

Various Activators

Viricidal compositions were prepared by first forming mixtures containing 2.58 g sodium perborate onohydrate, 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 containing TAED, and then dissolving into 1£ water. The peracid release rate was monitored using an iodometric titration on ice. The results are given in the following table.

TABLE 2

Titre (ml

Time TAED TAE NBC Granule 1 Granule 2

5 0.7 0.4 0.45 0.4 0.75

15 1.9 0.3 0.85 1.6 1.0

30 4.1 0.25 0.7 4.3 2.5

45 8.1 0.35 1.2 8.1 4.5

60 11.4 0.45 1.8 12.2 6.7

1 DAY 20 0.5 8.0 11.6* 18.8

* RESULT AFTER 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 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 Example 3 Storage Stability of Compositions Containing Surfactants

The following viricidal 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 reporting in the following table.

Table 3

Example No. 3.1 3.2

Linear alkyl benzene sulphonate 9% 9%

TAED 3% 3%

Coconut diethanolamide 3% 3%

STPP 20% 20%

C₁₇._ις alcohol-7ethoxylate 3.4% 3.4%

Citric Acid 6% 10%

Sodium perborate monohydrate 5% 5%

Sodium Sulphate to 100% to 100%

Loss of Avox 6.2% 13.4%

Example 4

Production of an Acidic Percarbonate solution using Citric

Acid and Sodium Percarbonate

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. In this experiment sodium percarbonate was used instead of sodium perborate. The following viricidal 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 peracid was determined by iodo etric titration carried out on ice. The solution to be assayed is added to a flask containing potassium iodide, acetic acid and ice. The iodine liberated is titrated with sodium thiosulphate. TABLE 4

Sodium 2.05 4.13 8.20 Percarbonate g

Citric Acid g 1.54 3.08 6.04

Time mins Titre (ml)

5 0.5 0.7 1.2

15 1.2 2.35 4.3

30 2.9 6.80 9.9

45 5.4 12.05 14.9

60 17.5 17.80 21.7 pH at 10 mins 6.39 6.38 6.35

Claims

CLAIM3

1. A process comprising reacting a peroxygen source with an activator compound which is an acyl donor in a first step in aqueous solution at a pH below pK_a(l) where pK_a(l) is the pK_a of the percarboxylic acid corresponding to the acyl group of the activator, to form a product solution comprising an oxidising product which is a stronger oxidising agent than the peroxygen source and subsequently using the product solution as a viricidal composition at a pH below pK_a(l) in a second viricidal use step.

2. A process according to claim 1 in which the product solution additionally also comprises a viricidal acid, preferably in a viricidally effective amount.

3. The process according to claim 2 in which at least a portion of the viricidal acid is present during the first step, preferably all the viricidal acid being present.

4. A process according to claim 2 or claim 3 in which the viricidal acid is sulphamic acid.

5. A process according to claim 2 or claim 3 in which the viricidal acid is citric acid.

6. A process according to any preceding claim in which in the second step the product solution is used to kill or protect against diseases of animals.

7. A process according to any preceding claim in which the first step is carried out at a pH from 5 to 9, preferably less than 7.0, or even 6.5.

8. A process according to any preceding claim in which the peroxygen source is present at a concentration of less than 5M and greater than 0.01M, preferably greater than 0.1M, preferably less than 2M.

9. Use of an oxidising composition comprising a peroxygen source and an activator which is an acyl donor to form the reactant mixture for the first step of a process according to any preceding claim, by adding the composition to water.

10. A viricidal composition comprising a peroxygen source, an activator which is an acyl donor and a viricidally effective amount of a viricidal acid such that when the composition is added to water the pH is reduced to and remains below pK_a(l) (as defined above) .