Note: Descriptions are shown in the official language in which they were submitted.
WO94/18297 2 1 ~ 5 ~ 3 ~ PCT/GBg4/oo~
Oxidiæina A~ents
The present invention relates to the in æitu
production of peroxygen-based 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 laundry detergent field
to use a combination of peroxygen bleach precursor (or
peroxygen source) and bleach activator in the same or
separate compositions. The bleach 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 hydLoxy 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 kA 1 i ~e
laundry detergents.
In WO-A-9312067 (unpublished at the priority date of
the present case) acylated citrate esters are used to
increase the bleaching effect of hydrogen peroxide. The
esters are incorporated into bleach booster compositions
which then appear to be used in conjunction with normal
laundry detergents. The bleach booster composition may be
acidic or alkaline.
WO94/18297 PCT/GB94/002
In EP-A-0241137 liquid laundry ble~rh~ compositions
are described which contain a disper~ion of a solid
particulate bleach activator in acidic aqueous hyd~oyen
peroxide. The preferred activators are substituted phenyl
esters of A 1 kAnQiC acids. The compoeitions are used in
conjunction with conventional laundry aetergents so that
the detersive solution ~.oduced is alkaline.
In the Wool Research Organisation of New Zealand's
Report No. R202 by S.J. McNeil of October 1992 the use of
sodium perborate solution in the shrink proofing of wool is
described. The perborate is used normally at alkaline pH
since acidification (using acetic acid) to neutral or
acidic (pH 4.5) is said to cause a loss of effectiveness as
the oxidising species is not formed. The perborate is, in
some instances, activated by the addition of tetraacetyl
ethylenediamine.
In American Dyestuff Reporter, June 1992, 34-41 El-
Sisi et al describe the activation of hydrogen peroxide
used in the prepration 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 concPntration
of peroxide is always 8g/~ (0.24M) or less. The
temperature of the reaction is 95C. The mech~n; sm of
activation postulated in this disclosure is different from
the me~h~;cm which is thought to be responsible for the
activation properties of com~o~.lds incorporated into
laundry detergents as bleach activator
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 Peroxi~P~", volume
1, D. Swern Ed, Wiley Interscience (1970) 313-335. Most of
the reactions described use the corrPspon~; n~ carboxylic
acid, the acid anhydride, the acid chloride or the aldehyde
as the starting materials for instance for a perhydrolysis
reaction using h~vyen peroxide. On~ of the reactions
W0 94/18297 2 ~ 5 ~ PCT/GB94/00228
.
uses the alkaline perhydrolysis of imidazolides of
carboxylic acids to form the peroxy carboYylic acid~
(Folli, U et al (1968) Bollettino, 26, 61-69).
In GB-A-931,119 a y~o~e~s for producing carboxylic
peroxy acids by reacting hydrogen peroxide with an ester of
the organic carboxylic acid in the ~h~nGe of water and in
the presence of a catalytic quantity of an acid catalyst.
The process is used to make peracetic, perbenzoic,
peradipic, perpropionic and peroxalic acids. The process
lo requires hydrogen peroxide to be dissolved into the liquid
ester, water to be removed and then acid catalyst to be
added only after complete removal of the water. In one
example the product solution was subsequently used to
oxidise cyclohexene to form cyclohexene oxide.
GB-A-930,056 describes a process for the reaction of
an aromatic carboxylic acid ester with hydrogen peroxide in
an alkane sulphonic acid to form the aromatic peroxy acid.
Hydrogen peroxide was added to the reaction mixture as an
aqueous solution having a concentration of at least 70%.
GB-A-1,363,916 describes anhydrous procecs~s for
producing percarboxylic acids which are aromatic or
aliphatic in nature by carrying out the reaction in the
presence of organic phosphorous compounds. The citation
contemplates the use of acid derivatives, including esters,
although anhydrides or the acids themselves are preferred
and there are no worked examples using other derivatives.
There may be some water left in the reaction mixture.
It is known to produce peracetic acid, a :j LL Gny
oxidising agent, in situ by reaction of acetic acid and
hydrogen peroxide, for instance to be used in epoxidation
reactions. The advantage of using the peracid rather than
hydrogen peroxide itself is that it is a :iL vl.~er oYi~i~ing
agent. Peracids are however unstable and can be dangerous
to transport in bulk. The problem with the in situ
reaction of acetic acid and hydrogen peroxide is that water
must be removed to drive the reaction or else a large
~Yoecs of one of the reactants must be used which
W094/18297 PCT/GB94/OOZ~
3~ 4
neceCci~ates 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
5 oxidation reaction will be acidic. Acetic: acid and acetic
anhydrides as starting materials for an in situ reaction
require speciàl precautions on h~Al in~ and æo are not
suitable for use in a domestic en~ironment. Acetic
anhydride is water sensitive and so requires special
storage conditions.
In FR-A-1176059 bleaching solutions for textiles are
made by ~AAing acetic anhydride to oxygenated water at pH
3 to 6. The solutions are used to bleach textiles at
temperatures in the range 50 to 104C. The production of
oxygenated water requires special apparatus.
In FR-A-1187519 the bleaching properties of hydrogen
peroxide solution at acidic pH is increased by the addition
of anhydrides of organic carboxylic acids such as acetic
anhydride. The resultant solution i8 used at high
temperatures, from 70C up to over 100~. The utility
appears to be in the industrial bleaching of fabrics.
GB-A-901687 and US-A-3227655 constitute similar disclosures
and describe the incorporation of heavy metal sequesterants
into the bleaching solution and the use of ammonia or
ethanolamine to regulate the pH. The æolutions are used at
temperatures of more than 60C to bleach fabrics. In all
of these disclosures the anhydride is incorporated in
stoichiometric or higher amounts as compared to the amount
of peroxide. Acetic anhydride is a liquid and reacts with
water and other ingredients on storage and is difficult to
formulate into a storage stable composition.
There have been descriptions of the in situ formation
of peracid and the subsequent use of the solution of the
peracid as a bleach under acidic conditions. However these
tend to be for specialised or industrial processes and/or
use activator comro~nAS which are undesirable. For example
in DE-A-2227602 dialkyl dicarbonate com~o~nA~ are used to
WO94/18297 PCT/GB94/002
5 ~1 S~ 63~
increase the bleaching effQct of hy~cGyen peroxide at a
range of pH's from acidic to Alk~l~ne. The mech~nism of
activation is not elucidated.
In US-A-3S51087 and US-A-3374177 a process is
described in which formaldehyde or a formic acid ester or
formamide is reacted with hydLGye.l 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 i8 part of the
industrial 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 co~LG~ive 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~ing compositions are
described which contain peroxy acetic acid as the bleaching
agent. Compositions into which peroxy acetic acid itself
is incorporated are acidic. It is suggested 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
emho~ircnt of the invention the aqueous solution formed
when the perborate and activator are dissolved is ~lkAl;~e.
It would be desirable to find a system with the
stability and advantages of the bleach precursor/activator
combinations used in the laundry detergent industry, 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 comry~n~
which is a C2 or higher acyl donor in a first step in
aqueous solution under acidic conditions, the pe~oxyyen
source being present in the reaction mixture
s~
at a concentration of less than 20M to form a product
solution containing an oxidising product which is a
stronger oxidising agent than the peroxygen source itself
and the product solution is subsequently used as a bleach
S under acidic conditions.
In such a process the peroxygen source is reacted with
an activator compound of the formula I
o
1 11
lo R -C-L
in which L is a leaving group and R 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 in which L and R may be joined to form a cyclic
compound, in a first "perhydrolysis" step in aqueous
solution under acidic conditions the peroxygen source being
present at a concentration of less than lOM in the
perhydrolysis reaction mixture, to form a product solution
containing an oxidising species which is a stronger
oxidising agent than the peroxygen source, itself and the
solution containing the oxidising species is used as a
bleach under acidic conditions.
Without being bound by theory, the present inventors
believe that the mechanism of reaction is that the
activator is perhydrolysed to form the percarboxylic acid
of the acyl group. The oxidising product, the
percarboxylic acid, is found to be a stronger oxidising
agent that than the peroxygen source. It is believed that
the activator of the formula I forms a percarboxylic acid
of the formula II
o
1 11
R -C-0-0-H II
The first step is consequently sometimes referred to
as the perhydrolysis step.
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.
. ,~
A~tlEh!2E~ S"EET
- - ~ 21~63~
. --
It is preferred that R1 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 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 heterocylic groups, for
instance joined to the C=O group of the compound I via the
heteroatom.
Substituents on R and L can include hydroxyl,
=N-R in which R is selected from any of the groups
represented by R1 and is prefrably 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 acyl-donor compound, usually an N-acyl or O-acyl
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.
Amide derivatives include acyl imidazolides as
described by Folli et al (op. cit.) and N,N-di acylamides.
other examples 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;
W094/18297 PCT/GB94/00~
~1L5~6 8
d) 0,N,N-trisubstituted hydroxylamines, such as 0-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 sulphuryl amide and N,N'-
diethyl-N,N'-dipropionyl sulphurylamide;
f) 1,3-diacyl-4,5-diacyloxy-imidazolines, for example 1,3-
diformyl-4,5-diacetoxy imidazoline, 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 the tetraacetyl or
tetrapropionyl propylene diurea and their dimethyl
derivatives;
j) Alpha-acyloxy-(N,~')polyacyl malonamides, such as
alpha-acetoxy-(N,N')-diacetyl malonamide.
k) 0,N,N-trisubstituted alkanolamines, such as 0,N,N-
triacetyl ethanolamine.
Alternatively the compound may be an ester, for
instance
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 succinimide, phthalimide and of imides of
other dibasic carboxylic acids, having 5 or more carbon
atoms in the imide ring.
n) sugar esters, such as pentaacetylglucose,
o) esters of imidic acids such as ethyl benzimidate,
p) triacylcyanurates, such as triacetylcyanurate and
tribenzoylcyanurate,
W094/18297 PCT/GB94/00~
~ 6~
q) esters giving relatively surface active ~Y~ ing
products for instance of C~ noic or -ar~ noic 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 (ISON08S) and benzoyloxy-
benzenesulphonate sodium salt (BOBS)
r) phenyl esters of C1422-alkanoic or -alkenoic acids,
s) esters of hydroxylamine,
t) g~in~l diesters of lower alkanoic acids and gem-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 perph~lic acid
x) isatoic anhydride or related compounds such as
described in WO-A-8907639, for instance 2-methyl-(4H)3,1-
benzoxazin-4-one (2MB4) or 2-phenyl-(4H)3,1-benzoxazin-4-
one (2PB4) and
W094/18297 PCT/GB94/00228
6~ ~
y) polymeric anhydrides such a8 poly(~dipic) anhydride or
other compounds described in our co-pPn~ing application W0-
A-9306203.
In the process of the invention the precursor
peroxygen source may be l.yd~Gyen 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, more preferably about 6Ø The pH in the
hydrolysis step is usually more than 2.0, preferably more
than 5Ø
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 ~oncPntration 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
concerted). Preferably the concentration is less than 60%
weight by volume and more preferably lsss 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 ~AnAl in~ the
products, it is preferred for the co~contration to be less
than 15% or even 10~ w/v or less than 5% w/v. 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 conce~trations of hy~L~yen
peroxide. The concentration of p~Gxyyen æource in the
aqueous liquid is for instance less than lOM, preferably
less than 5M or sometimes even less than 3M down to O.OlM.
Preferably the ~ tration is at least 0.05M, more
preferably O.lM, even more preferably at least 0.2M.
WO94/18297 PCT/GB94/002~
3 ~ `
11
The pH in the bleaching step is usually le~s than 6.5,
preferably less than 6Ø The pH is usually more than 2.0,
for instance more than 3.0, moæt preferably more than 5.O.
In the perhydrolysis step of the reaction the
temperature is preferably in the range 0 to 95C, more
preferably in the range lO to 80C. The invention is most
useful when the temperature is less than 60C, or even less
than 50C, for instance less than 40C or 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 æafety point of
view.
The present invention provides also a new use of a
composite product comprising starting materials for the
perhydrolysis reaction. Preferably the product can simply
be added to water to provide the entire reaction mixture.
The product therefore comprises a peroxygen source, an
activator compound as well, if neceCcA~y, as components for
rendering the pH of an aqueous solution to which the
components of the product are added acidic. Acidifying
components may not be n~CQcc~ry where the peroxygen source
itself is sufficiently acidic to achieve the desired pH.
In one preferred embodiment of the composite product
the activator is a solid anhydride compound. The peroxygen
source may be hyd Gyen peroxide or a solid peroxygen
compound.
In another preferred embodiment of the composite
3s product the activator is other than an anhydride.
W094/18297 PCTIGB94/00
2 ~5 ~36 12
In another preferred emh~imen~ of the composite
product the peroxygen source is a solid, preferably an
inorganic persalt.
An acidifying co~ponent may comprise an acid and/or
buffering material. The compQne~t may comprise a polyba~ic
organic acid, such as a polybasic car~oxylic 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
lo 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, such as glycols and pol~ols, boric acid, or
sodium dihydrogen phosphate can be used. Such acidifying
components are also suitable for use where percarbonate is
the peroxygen source.
Although the composite ~od~ct may contain the
individual components each in separate compositions, for
instance one of which contains the ~e~oxy~en source,
another of which contains the activator and another of
which contains an acidifying component, it is preferred to
provide at least the activator and acidifying component as
a mixture in a single composition in a form in which they
are stable. Such a product 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 compcsition, in which
the components do not react, and which i8 preferably
therefore substantially waterfree.
The product(s) may be in liquid form, for instance in
a non-aqueous liquid medium, in which the compQn~nts may be
dissolved or dispersed. For instance particle~ of
activator with protective coatings, for instance pr~l~ce~
by microencapsulation te~n;ques or spray coating of solid
activator, may be suspended in an aqueous, or non aqueous,
WO94/1~97 PCT/GB94/002~
2~
13
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 pe~oxyyen ~ource or
activator may be disrupted or diluted in to water or with
abrasion.
Preferably the or each composition of the composite
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
components. Such particles may be provided by te~hniques
similar to those used in the laundry detergent industry,
for instance including particles produced by spray drying
liquid slurries, by granulation t~çhn;ques using binders
(for instance synthetic or natural polymers or derivatives)
or by melt blending followed by extrusion or other
t~ch~ i ques.
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 S00%, preferably 5% to 150% of the
stoichiometric amount of activator tfor 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 composite product may include other additives, for
instance stab~ e~s which stabilise the product before
use, as well as stabilisers for the peroxy acid oxidising
species formed in the reaction, especially 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
W094/18297 PCT/GB94/00
14 ~
act as diluent. Other ingredients may be included
dep~n~; ng on the mode of use of the composition on the
final application of the reaction product, for instance
perfumes, or agents to assist dissolution or dispersion of
the product into water.
A preferred emho~ent of the composite product for
use in the present invention comprises a peroxygen source,
an activator compound, a surfactant and, if necesc~ry, an
acidifying component.
lo The reaction product of the perhydrolysis reaction is
preferably used immediately, without removal of any by-
products or addition of other materials, in the second step
in which it is used as a bleaching (including disinfecting)
agent. Sometimes it may be desirable to add additional
ingredients for the second step such as pH-adjusters,
surfactants/wetting agents which may be cationic, anionic,
amphoteric or non-ionic, or other additives to im~Gve the
second step of the process for instance co-disinfectants,
biocides, slimicides, enzymes, enzyme inhibitors or radical
scavengers, abrasives etc. Cobiocides are particularly
valuable where the primary objective of the ~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
re~llce~ or removed, non-coloured stains are reduced or
removed and/or a substrate is disinfected. For instance
the second step may include processes in which hard
surfaces eg floors, food preparation surfaces, utensilæ,
toilets, washing facilities in domestic, industrial or
institutional applications are cleansed, and bleaching
processes for fabrics (for instance during fabric
manufacture and dyeing). The second step may comprise
water, effluent or sewage treatment as a biocide, pulp and
paper bleaching, paper de;nking~ wood bleaching, fibre and
fabric manufacture, use as an biocide, fungicide,
bacteriocide, sporicide and/or viricide, as a contact lens
WO94/18297 PCT/GB94/00~
21~
disinfectant or general disinfectant for use inter ali~ in
general environmental clean up. Furthermore the second
step may be used in food ~rG~uction 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 bl~ching or tooth or
denture white~i n~ and/or disinfecting.
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 cleaning 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
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, cellulose fibres,
especially in paper de-inking operations, and in general
environmental clean-up operations.
WO94/18297 PCTIGB94/002
16
A second category of composition comprises liquid
formulations but which contain no sur~actants. The~e may
be useful where no surface activity is n~oe~s~ry, for
instance in effluent and water trea~ent, 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 sterilication
and in some domestic sterilisation situations, for instance
as a general toiletry disinfectant, in denture cle~ni~g
compositions, in sanitising glass and plastic bottles or
other containers, as well as in certain environmental
clean-up operations. Furthermore, where the composition is
to be used as a general industrial oxidation reaction, it
may be undesirable to include a surfactant.
The liquid formulations mentione~ 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 cle~n;~g 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
solid form, 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
3s easier to isolate other components of the composition from
one another and from the blea~h components, especially
WO94/18297 PCTtGB94/00~8
,-- .
17~ 3 6
where storage sensitive com~ s such as Qnzymes, other
biocides or perfumes are present.
Solid compositions may be in the form of particulate
mixtures or may be tabletted. Tabletted formulations, or
even granular formulations, may include agents to increase
the dissolution rate of the compositions upon addition to
water. For instance suitable components incoL~o~ating 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, dispersants,
opacifiers, hydrotropes, dyes, perfumes etc.
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
Reaction of TAED and hydrogen peroxide
1.1 This area of investigation was to find a simple method
of determining the presence of a stronger oxidising species
rather than l.yd-oyen 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 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
by hydrogen 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 mechAnicm. TAED (22.8g
O.lmol) was added to 60% hydrogen peroxide (60mls lmol).
The mixture was stirred for 10 minutes. A 2ml aliquot was
W094/1~97 5636 18 PCT/GB94/nOZ~
removed and added to alizarin complexone ~olution (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 BC1 (tea and clay). Comparisons were made between
the bleaching performance of 60% H202, 10% PA~H 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 60 ml 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 att~i~Ahle 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 ble~rhing ~oye~Lies.
Three systems were set up, one cont~;ning Dequest 2066 (an
alkylene polyamine polymethylene phosrho~c acid) as a
sequestering agent, one with 0.5mls 20~M Fe(III) solution
added and one with hydrogen peroxide onl~. All of these
were carried out at pH 6. The results are shown in Table
3.
WO94/18297 PCT/GB94/00228
~ 3 ~
1.6 Result & Discussion
All experiments carried out at room temperature in
open beakers. Dwell time in the bath of 1 hour.
Table 1
E~umple Sl-in Rcd W~ne To
Ble ch- loithl Fu~ itiel Bti~ F~l Bd~
u4~ B~ ht~ B~htne~e
ohtio~l
1.1 T~EDIH 46.5 74.8 25.0 63.9
22 60~G
1.1 H20, 46.5 69.7 2S.8 46.6
1 0comp Comp
1.2 P~AH 46.5 76.7 25.7 61.0
comp
1.3 HCI 46.5 63.9
com~o
WO 94/18297 2 ~5 63 ~ PCT/GB94/00228
~n
~n
a)
_~ r u~ m
S CO ~0
S ~D
~o I
er
. I
.4
E~ )
H
~1 oN
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--I O ~ O
0 E D
C
U
X N ~,
a:
U~ O ~
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wo 94~18297 2 ~ ~ 5 ~ ~ 6 PcTlGB94/00228
21
~1 0 ~ t`~ 0 t~
_, ,~ . . . . . .. . .
~ tr Uq t~ 1 ~ d~ In U~ ~
~m ~
.
--1 S 1~ d ~D ~ ~ ~~D ~ Ul ~
H ~ ~
~ICD O O In
er . . . .
~ O O O ~D O ~ CD
E~
~ ~ t` O ~1 ~ ~ OD O ~1
a~ .c . . . . . . .
J a5 U~~110 1 0 a~ O
.~ . .. .
:C C
R. H
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O O O O O O O O ~ -- ô Ul
:~ a ~ a c ,~ ~ a a a ~ ~ ~ ~ o
~q
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. --I o o o
E~ . .
u~ o ~
~ .1
WO94/18297 PCT/GB94/00~8
g~ --
22
Notes: With 60~ hy~oyen peroxide and TAED at the higher
end of the acidic pH range bleaching was visible on
contact, with the other solutions the bleaching was much
less rapid. On reaction there was efferv--~nce 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 contA;n~ 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 peracetic acid under
these conditions. The formation of an acidic species when
TAED is dissolved in hy~Gyen 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 æpecies in solution. It is assumed
from this evidence that peracetic acid is likely to be the
bleaching/oxidising species responsible for the bleaching
effect, although it may be a by-product, an intermediate or
the product of further reaction of another strong 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.
WO94/18297 PCT/GB94/00~8
~ ~S~6~i
Example 2
TAED, ~ADHT, SNOBS, BQBS, 2M~4, I$0NQBS as activators for
peroxygen bleaches at acidic ~H, for stains in solution and
on fabrics
2.1 ExDerimental
2.1.1 8watches
The activator/peroxygen source combination used was
60% hydrogen peroxide in a 10:1 ratio with the activator.
Small swatches of cloth (20-25cm2) were used and the stain
was chlorophyll. The bleaching experiments were run using
10mls hydrogen peroxide (60%) which was adjusted to the
required pH using sodium hydroxide solution. A weighed
quantity of the activator (sufficient to produce 33mmol of
peracid) 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 deionised water to
remove any rP~-; n ing traces of bleach, dried by the
technique 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 Th~ dep~n~nc~ of pH on tim~
Experiments to monitor the relationship between pH and
time were carried out using TAED, BOBS, SNOBS, 2MB4 and
DADHT as activators. The pH of 60% hydrogen peroxide was
adjusted to about pH 6. To 20mls of this solution was
added 33m mols of activator. The pH was measured with
time. The results are shown in Table 6.
2.1.3 Timed bleaching
Timed bleaching experiments were carried out using the
same ~chn; que and quantities as in 2.1.1 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
rinsed in deionised water after set time periods. The
W094/l~2~s5~ 3 ~ PCT/GB941002
24
times used were 5mins, 10mins, 20~ins, 30mins, Ihr and
2hrs. The final brightness after drying by the usual
t~chnique was determined using the Hunterlab. The results
are shown in Table 5.
5 2.1.~ TiIIl~/p~I bl--rh~n7 profilQ
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 Smins and then removed
and rinsed thoroughly with deioni~e~ 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 perbor~te solutions in th~
presenc~ of aci~ifying 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 deionised
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.
Two lots of sodium perborate tetrahydrate (20g) mixed
with sodium dihydrogen phosphate (17.5g) (to reduce pH)
were prepared. To one of these SNOBS (4.4g) was added.
The mixtures were added to lOOml deio~ic~ water and a
chlorophyll st~ine~ swatch ~e~ to each solution. After
1.5hrs the swatch was removed and the brightness measured
on the Hunterlab. The pH was ~easured at timed intervals.
2.2 Results and Discussion
2.2.1 The chloL~l,yll 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.
W094/18297 PCT/GB94/00~
215~3~
2.2.2 Of the other activators BOBS and SNOBS gave the
quickest results with DADHT fairly close boh i ~A . ISONOBS
and TAED reacted more slowly. It should be noted howeve~,
that the activators are used on equivalent molar basis
(i.e. equivalents of acyl group released) so that the
- weight of TAED is less than, for instance, the weight of
SNOBS and BOBS. The blank experiments with peracetic acid,
water and hydrogen peroxide (at both pH 6 and pH 1) show
that activation is occurring, when the activator i8
lo 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
varied with different activators due to differences in both
the acid being produced and the rate of perhydrolysis.
BOBS was difficult to use, as addition to peroxide produced
a thick frothy paste. It was because of this that SNOBS
was used in subsequent experiments. The problem is
probably due to the surfactant properties of these
activators, a property which is important in some
applications. This increases the wetting ability of the
peracid solution.
2s 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.
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 bl~ ing
solution the cloth was removed and rinsed with deion;~^~
water. Comparing of the different swatches, for the same
WO94/18297 PCT/GB94/00~
~5~63~ ~
26
activat,or, gave a measure of the stability, rate of peracid
release and pH dep~n~nce of the bl~ n~. The
relationship between these variable i8 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 ble~c~;ng but after
an hour the efficacy was similar (Table 7). This ~eems to
show that DADHT released strong oxidising agent more
rapidly initially but after time gives a similar
concentration. This is borne out by the pH measurements.
The pH of the solution contA; n; n~ DADHT decreased more
rapidly than that of the TAED cont~;n;ng solution. After
20hrs the figures were much closer (Table 6).
2.2.7 SNOBS was seen to give better bleaching at all
times in this test, i.e. up to 2 hours. The release of
strong oxidising species seemed to be slow. The cloth
added after lmin showed less bleaching than those added
later (Table 2). In all cases the stability of the bleach
activation with time was remarkably good. There was
noticeably better bleaching than with peroxide alone in all
cases.
2.2.8 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. When SNOBS was incorporated
into such a solution there was noticeably ~uicker bleaching
than occurred without any added activator. The pH of the
solutions was seen to be acidic (pH 6.4 with phosphate and
pH 5.1 with citrate) and much more stable than seen with
more ro~c~ntrated peroxide solutions. The pH of the
activated and unactivated solutions was very similar in
both cases.
WO94/18297 pcTlGs94loo~8
~ls~e~
27
Table 4. Activating acidic peroxide with different
activators.
E~umple ~aivctor Initi-l pH Fm-lpH Initicl Bd~btn~ Fu~-l Bd~h~
2.1 T~ED 6.00 2.47 14.26 38.4
(30miD)
2.2 ISONOBS 6.00 3.22 14.26 48 S
23 BOBS 6.00 23S 14.26 7S.2
2.4 SNOBS 6.00 2 S8 14.26 n.4
2.S DADHT 6.00 233 14.26 61.3
2.6 2MB4 6.00 - 14.26 24.8
2:1 Comp Bl~nlc 6.00 5.96 14.26 30.9
~o2)
2.2 Comp Bl~nlc 7 S0 S.68 14.26 19.7
ff~O)
2.3 Coolp Bl~ - - 14.26 S9.2
2.7 T~ED 6.00 - 14.26 21.8
(lOmiD)
W094/18297 PCT/GB94/00~
3~ ~
28
Table S. The effect of different bleaching times on
brightness and solution pH.
Tim~/ Final b i~l.Ln2s~ pH aftQr 2 hr~
mins
TAED 8NOBS DADHT TAED SNOBS DADHT
27.8 47.8 48.8 3.21 3.64 3.15
33.5 58.7 57.4 3.09 3.64 3.15
46.2 80.8 60.6 3.20 3.53 3.17
52.2 81.5 68.2 3.15 3.51 3.15
57.1 82.6 79.8 3.18 3.61 3.21
120 74.1 81.9 84.5 3.21 3.50 3.14
~able 6. The effect of activators on solution pH with time.
Time/ ~H
mins
TAED BOBS DADHTSNOBS
0 6.18 6.18 6.05 6.05
1 5.29 - 4.83 5.16
2 5.03 - 4.50 5.01
3 4.85 4.77 4.23
4.62 4.10 3.96 4.81
7 4.47 3.95
9 4.35 - ..
4.31 3.79
4.00
23 - - 3.26
24 - - - 4.44
3.86
31 - 3.62
- - 3.11 4.18
3.64
107 - - 3.95
1200 3.27 - 2.5~ -
WO94/18297 PCT/GB94/00~
~ ~ 5~3 ~
Table 7. Bleaching efficiency against time.
~im~/ Initi~l Final Bri~l.Ln~
m1 n- Br~
TAED DADHT SNOBS
1 14.26 32.0 34.1 42.6
~ 15 14.26 31.9 32.7 40.6
14.26 28.7 26.9 54.3
14.26 25.8 20.9 53.3
SNOBS - sodium nonanoyloxybenzene sulphonate
BOBS - benzoyloxybenzoic acid sodium salt
DADHT - 1,5-diacetyl-2,4-dioxohexahydro-1,3,5-triazine
2MB4 - 2-methyl-(4H)3,1-benzoxazin-4-one
(cf. WO-A-8907639)
ISONOBS - Sodium isononanoyl oxybenzene sulphonate
Exam~le 3
Biocidal activity of activator/hYdroqen peroxide mixtures
3.1 The assessments were performed in a test tube
situation following the principles of BS 6471:1984.
3.2 100ml volumes of Nutrient Broth were ;nso~llAted with
Escherichia coli, StaphYlococcus aureus and Streptococcus
faecalis.
3.3 A 150mg/l solution of peracetic acid (PAA) was used
for comparison. This was prepared in sterile distilled
water.
3.4 In order to achieve concentrations comparable with the
comparative 150mg/l PAA solution, test solutions of the
formulations were prepared using TAED, SNOBS or acetic
anhydride in the amount noted in the respective table below
in 100ml of 1% hydrogen peroxide solution. In example 3.6
the test solution was left to age for 24 hours before use.
Other test solutions were used immediately after make up.
3.5 lml of the test bacterial culture was added to 9ml of
the appropriate formulation, mixed and left for a period of
time at a given temperature. (The conditions are noted in
the respective table below.)
3.6 lml of this liquor was transferred to 9ml of
inactivator comprising 50g/l sodium thiosulphate and
WO94/18297 ~ 3~ PCT/GB94/OOZ~
0.25g/1 cat~lAQe in distilled water. The inactivator waC
filter sterilised using 0.45~m membrane filters. (Example
3.9 using acetic anhydride as activator was inactivated by
dilution with MRD (see below) alone.)
3.7 From these inactivated liquors, lO-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 oo-.L~ols the procedure was repeated using lS
hydrogen peroxide as the control for the test 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 compound to
the control solution is calculated. The results quote the
log (base lO) of the control count/test count. Where the
figure is "more than" the figure quoted this indicates the
cfu count in the test plate was below the minimum which can
be quantified using this ~e~h~ igue.
3.lO Results
Table 8 - Biocidal efficiencies
Ex-mple Activ tor Tlme Temp 1~ retuction
min~
TypeAmount E. ColiSt-ph. ureu~Stl~p. fi~ec-li
~100ml ~O2)
3.1 TAED0.0225 5 mom1~ 0 >0.70
3.2 TAED030 S room 034 0 0
2 533 T~ED0.03 S 40-C4.2l 2.02 >4.96
3.4 T~ED0.03 10 oom 0 1.13 2.23
3 S TAEDO.IS 10 ~om~S.I9 OS4 >S.31
3.6 T~ED0.03 10 ~om>3.420.87 ~4.60
3.7 NOBS0.375 S n~om >4.03 0.41 ~6.18
3 03.~ NOBS0.045 S r~om l.SS 0 3.14
3.9 Acetlc 0.07 10room >3.23 0.87 ~4.60
nhydride
3.10 percet;c~cid S mom>6.831.68 >6.46
3.ll In general none of the formulations tested was
particularly ef f ective against Staph. aureus.
WO94/18297 PCT/GB94/002~
s~
3.12 Low concentrations of TAED with H2O2 generally d~d not
appear to be particularly effective when compared with PAA
although some reduction was seen against ~.coli.
Increasing the temperature, increasing the contact time and
the solution to age were all found to increa~e the
effectiveness.
3.13 Acetic anhydride is an adequate activator under the
test conditions, giving a total kill of E. coli and Strep.
faec~l;s.
3.14 SNOBS/H2O2 was much more effective than TAED/H2O2
against all three test organisms. No growth was obt~ine~
from the treated cultures of E.coli or Strep. faecalis
whilst the number of Sta~h. aureus colonies recovered was
reduced by over half, although a remaining count of 1.5x103
was still obtained.
3.15 PAA was more effective than SNOBS/H202 as, besides a
total kill of E.coli and StreD. faecalis, at higher
concentration it also reduced the numbers of recovered
Sta~h. aureus by 98%. However, this figure of 98% still
left over 3.Ox104 cfu/ml recoverable.
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 A~ 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 pr~C~n~e of
hydrogen peroxide was determined by iodometric titration as
described in Example 5 below.
W094/18297 PCTtGB94/00~
3~ ~
32
~ TABLE 9
Sodium 2.054.13 8.20
Percarbonate g
Citric Acid g 1.543.08 fi.04
Time mins Iodometric Titrations
0.5 0.7 1.2
1.22.35 4.3
2.96.80 9.5
5.412.05 14.g
17.517.80 21.7
ph at 10 mins 6.396.38 6.35
Example 5
Acids and anhYdrides as activaters
5.1 Usinq acetic acid (comparative) and TAED (invention)
as the acetyl donor.
The following experiments were carried out using 50ml
10% by hydrogen peroxide at room temperature with activator
and compared against controls. Chlorophyll st~; n~
swatches were used as the substrate~ Reflectance was
measured using an ICS Texicon Spectraflash 500 (a
colorimeter using the CIE Lab 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
S~ i n~ swatch after rinsing with deionised water and
drying as in the previous examples.
WO94118297 ~ PCT/GB941002~
.
33
Results
Table lO
Example Reading Solution Activator Initial
PH
5.l.l l.6 50 ml H2O2 TAED 3.35
lighter 3.17g
5.l.2 Comp 0.35 50 ml H2O2 Glacial 2.32
lighter Acetic
l.67g
5.1.3 Comp 0.75 50 ml H2O2 - 3.33
lighter
5.l.4 Comp 0.2 50 ml H2O Glacial 2.62
darker Acetic
l.67g
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 anhydride (comParative) and ~AED
(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. IIydLo~en peroxide was
used at 10% w/v. A range of st~i~e~ swatches were used,
these were chlorophyll, curry and blackberry. Samples were
also assayed for peracetic acid using an iodometric
titration.
WO94/18297 PCT/GB94/00228
34
5.2.1 Bleaching s~ained swatches
In the following experiments the peroxide/activator
combinations shown in Table lO were used to prepare the
bleaching solutions. ~
All experiments were carried out at ambient
temperature. Formulation 5.2.4 Comparative was only used
in the first two experiments. The reflectance was measured
as in 5.1. In the table the reflectance differences are
noted. A positive value means the bleached ~watch is
lighter than the control stained swatch and a negative sign
means it is darker.
Experiment A
Chlorophyll st~; n~ swatches were added to these
solutions and left to bleach for 75 mins. After this time
the swatches were removed and washed in water to remove any
remaining active species.
Experiment B
Chlorophyll st~ 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 C
Fresh solutions using the f irst three compositions
were prepared and allowed to stand overnight before
chlorophyll stained 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
st~;ne~ swatches. There was no water/acetic anhydride
solution (5.6 comp) tested.
Experime~t ~
This was the same as experi~ent A using blackberry
stained swatches. There was no water/acetic anhydride
solution (5.6 comp) tested.
5.2.2 Iodometric titration
The solutions 5.2.1 and 5.2.2 (comp) used in
experiment E were tested at intervals f or peracetic
WO94/18297 21 5 5 ~ ~ 6 PCT/GB94/002
concentration using an iodometric titration carried out on
ice, the titration being carried out immediately, so that
hydrogen peroxide present would give minimal titres and
primarily ~L~olly oxidising agent is determined.
5.2.3 Results
Tablell
Solution ActivatorpH in n~rlc~ _ Dirf~ .Ke
A B C D E
5.2.1 50ml 3.17~ TAED3.47 1.3 4.4 0.38 1.3 8.6
H22
5.2.2 Comp 50ml 2.4~ acetic 2.10 3.2 8.6 1.6 1.3 10.2
H202 a.)i, ~J- id~
5.2.3 Comp 50ml - 3.69 0.6 1.0 0.67 1.2 8.2
H22
5.2.4 Comp 50ml 2.4~ acetic - 0.48 ~.4 - - -
H20 anhtd~id~
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.
5.3 Determination of the peracetic acid produced by acetic
anhydride (comparative) and TAED.
The conc~ntration of ~L~ol,y oxidising agent was
determined at time intervals using an iodometric titration
on ice. The solutions studied were those used in
experiments S.2.1 and 5.2.2 Comp Experiment E as
experiments 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.
WO94/18297 ~ ~ 36 PCT/GB94/00
- Table l2
Time/hr Amount of SL~olly Oxidising Agent r
5.3.1 (TAED) 5.3.2 (acetic anhydride)
1.5 0.19 1.16
3.7s 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 concentration of
peracetic acid. However over time, in this case 7 days,
the TAED solution increases in strong oxidising agent
concentration while the acetic anhydride solution loses
oY;~i~ing agent. After several days the levels of strong
oxidising agent are higher in the TAED cont~ g solution.
There is still a large volume of TAED left lln~i~solved
after about 140 hrs. This makes thi.s a very good slow
release procedure.
Example 6
The use of penta-acetvlqlucose (PAG) as activator
6.1 This experiment is to determine the efficacy of PAG as
an ester as a bleach activator under acidic conditions.
The bleaching experiments were carried out using
chlorophyll stained swatches. The three formulations shown
in Table 15. The samples were allowed 75 mins bl~hing
time. In a further stage to investigate further release of
~Llo~,y bleach 3 drops 50% w/w NaOH solution were then added
to formulations 6.1 and 6.1 comp. A second swatch of
material was added and bleached for 25 mins. Formulation
W094/1~97 21~5~ PCT/GEJ4100Z~
6.3 was at pH 5.6 immediately after NaOH addition (pr~or to
this no bleaching occurred), 6.2 comp showed a pH of 7.5.
After 2 hrs pH of 6.3 = 3.ll, of 6.2 comp = 6.84.
The lightness, strength and colour after drying using
an iron as described in Example l above determined by the
use of a ICS Texicon Spectraflash 500 (a colorimeter which
uses the CIE Lab) using version 4.70 software.
6.5 Results
Table 13
Ex~ le solutioD Aa;~/~tOr N OH~t l;ehtne~ StleD~th Colour
7S m~n
6.1 20ml}~0, 6.51yPAO - 0.1 -2.1 1.9Y
609~
6.1 Comp lOml J~ 0.8 0.7 Y
60~i
6.2 lOml }~2 0.6S~P~G - -0.3 -1.8 1.7 Y
10%
lS 6.3 6.1 + 11.1 -3.9 6.S Y
6.2 Comp 6.1 Comp + 8.1 -1.9 2.5 Y
Y is yellower Positive results in the table indicate
lighter, stronger more yellow, respectively.
6.4 The results show that PAG is an effective activator
under acidic conditions. The efficiency d~p~n~c markedly
on the pH of the solution. The more strongly acidic the
peroxide solution the less effective the activation.
Exam~le 7
Perborate/TAED in a non-surfactant containin~ comPosition
A mixture of the following powders was made and added
to le of water:
1.8 g TAED
2.58 g sodium perborate monohydrate
without or with l.58 g sodium bicarbonate
varying amounts of citric acid or sodium dihyd~G~en
orthophosphate as acidifiers. The pH of the solution at
the varying amounts of acid compQn~nt were measured after
lO mins. The results are shown in the following table.
WO 94/1829~ G~ PCT/GB94/00228
38
C~l , CD
~t
~o
a~
o
o. U~
0 't ~
.~ CD
~ a~
,1
E
~,
In ~ ~t
~D
U~ ~ ,`
o
,~
~ ,` CO
_ a~ OD
C Z
~D ~ O
o
W094/lU97 2 ~ 3 ~ ~CT/GE94/0~
The bleaching performance of some of the solutions was
determined on un-glazed, tea-S~ine~ tiles. The bleaching
solution is applied to one half of the tile and the
difference in whitoness, 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 r~in~ 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 8
Surfactant - 3 Com~ositions Includin~ Perborate and Various
Activators
Mixtures cont~;n;ng 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 1e water.
The peracid release rate was monitored. The results are
given in the following table.
TABLE 15
Oxidisina agent amount for ~he followin~ activators
Time TAED TAE NBC Granule 1 Granule 2
0.7 0.4 0.45 0.4 0.75
1.9 0.3 0.85 1.6 1.0
25 30 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 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
WO94/18297 PCT/GB94/002~
63~ ~
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 40C
Example g
Storage Stability of Com~ositions Containing Surfactants
The following compositions were formulated by blen~ing
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 a st~n~rd Avox titration. The percentage loss of
available oxygen is reported in the following table.
TABLE 16
Example No. 9.1 9.2
Linear alkyl benzene sulphonate9% 9%
TAED 3~ 3S
Coconut diethanolamide 3~ 3%
STPP 20~ 20%
C,~,c alcohol-7ethoxylate 3.4% 3.4%
Citric Acid 6% 10%
Sodium perborate monohydrate 5% S%
Sodium Sulphate to 100% to 100%
Loss of Avox 6.2~ 13.4%
Example 10
Oxidisinq Aqent Concentration for Various Activators at pH
6.3
Mixtures comprising 2.58 g s~dium ~e~LoLate
monohydrate, 1.58 g sodium bicarbonate and 21 g sodium
dihydrogen orthophosphate and 1.88 g of activator, and
dissolved into 2 litres of water. The concentration of
strong oxidising 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.
wo 94/l82g7 21 5~ PCT/GB94/00~8
.
41
T~RT.~ 17
A~ount of oxidininq ~gent for diff-r~nt acti~ato--
T~me 2MB4 2PB4 PAG IA TAE SNOBS TA~D
5 min 2.25 0.15 0.9 0.45 0.85 .6
15 min 2.55 0.3 0.9 0.8 0.25 1.1 1.7
30 min 1.70 0.35 0.6 1.1 0.4 1.3 3.6
45 min 1.10 0.45 0.7 0.9 0.4 1.4 5.1
1 hr 0.85 0.6 0.4 1.0 0.35 1.4 6.3
1 day 0.40 0.3 0.3 - 0.4 1.1 10.6
IA - isatoic anhydride
2PB4 - 2-phenyl-(4H)1,3-benzoxazin-4-one
These results show that, although the initial release
rate for strong oxidising agent by SNOBS is higher than by
TAED, TAED gives bette~ long term release, continuing to
increase even after one hour. 2MB4 gives an extra quicker
initial release rate but the effect diminishes after a
short period of less than half an hour.
ExamPle 11
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/~), sodium perbor~te monohydrate (at 2.58
g/ e ) 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
tile and then either dipped in water or wiped with a cloth
to remove the liquid. The whiten~æs 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.
