Note: Descriptions are shown in the official language in which they were submitted.
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~ETALLO-PORPHYRINS FOR USE AS BLEACH CATALYST
This invention relates to improved metallo-porphyrins
for use as a bleach catalyst in the bleaching of fabrics
and to compositions for the cleaning and bleaching of
fabrics comprising said metallo-porphyrins.
It is known that metallo-porphyrins can act as an
oxidation catalyst. W0 88/07988 describes the use of
metallo-porphyrins as catalyst in a variety of oxidative
reactions. U.S~ Patent N 4,077,768 describes the use of
lo iron-porphyrins with an oxidising bleach, e.g. hydrogen
peroxide and al60 peracids, in aqueous wash li~uors for
dye bleaching in solution, i.e. for inhibiting dye-
transfer during the washing of fabrics. It i6 also known
from EP-A-0306089 (published 8 March 1989) that metallo-
porphyrins under careful conditions can effectivelycatalyse the fabric stain bleaching action of peroxyacid
bleach systems, thereby making the peroxyacid more
effective for use in the washing of fabrics at the lower
temperature region of between about lO-C and 40C. A
drawback of metallo-porphyrins as bleach catalyst is
that they are themselves unstable against oxidation by
the oxidising bleach. Although the mode of action of
metallo-porphyrin bleach catalysis is not fully
understood, it appears that in the presence of an
oxidising bleach the metallo-porphyrin catalyst forms an
intermediate substance. This can react with substances
able to be oxidised and bleached, whereby the catalyst
is reformed, and this is the desired reaction. However,
the intermediate substance can also react with a second
metallo-porphyrin forming a dimeric -oxo bridged
species which is ineffective as bleaching agent and
quic~ly degrades under the oxidative conditions.
Reaction of the metallo-porphyrin with hydrogen
peroxide, in the absence of a substrate, results in
degradation via a different pathway in which radicals
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are believed to play a role. It is thus necessary that
careful measures should be taken to avoid the metallo-
porphyrins being oxidised. In the bleaching of fabrics
with peroxyacids, the art teaches that metallo-
porphyrins must be pre-adsorbed on to the fabric to
exert their catalytic activity on stain bleaching. Even
80, some loss of catalyst due to decomposition, with
consequent reduction of catalytic activity cannot be
avoided.
The invention now provides improved metallo-porphyrins
as peroxyacid bleach catalysts which are more stable
against oxidation by mono oxygen donor type oxydators
(like peroxyacids, hypochlorite and tert.butyl
hydroperoxide), than the metallo-porphyrins suggested in
the art for u~e in the bleaching of fabrics.
The metallo-porphyrins for use as peroxyacid bleach
aatalyst in the bleaching o~ fabrics according to the
invention are compounds having the follo~ing structural
formula:
2 Ar 3
251 ~ ~ 4
~ N ~ ,N ~
Ar ~ ,Me ~ Ar (I)
8 ~ 5
wherein Me is a metal ion, selected from Mn(III) and
Fe(III); and Ar is a substituent selected from the group
2~ )h7
c 7150 (R)
consisting of
Xl X
~=~ (B)n-(A)m >=~
(a) ~ : (b) ~ N+ - (B)n~(A)m
X2 X2
and
X
>~
(c) ~ ~(CH2)n - N - (B)3
X2
wherein n and m may be 0 or 1; A may be sulphate,
sulphonate, phosphate or carboxylate groups; B is Cl-C10
alkyl, polyethoxy alkyl or hydroxy alkyl and Xl and X2
are Cl, Br, CH3, C2H5 or CH30.
Although not es6ential, the porphyrin core formula (I)
may be substituted at one or more o~ the remaining
carbon positions indicated by the numbers 1-8, with e.g.
Cl-C10 alkyl, hydroxy alkyl or oxyalkyl groups.
The phenyl or pyridyl group (a), (b) or (c) may or may
not contain other 6ubstituent~, but it has been found
that improved 6tability is only achieved if the Xl and
X2 ~ubstituent6 are attached on the phenyl or pyridyl
group at exactly the indicated places near the porphine
core. Xl and X2 substituents attached on other places of
the phenyl or pyridyl group such as:
(B)n~(A)m ~ ~
~ or ~ N - (B)n~(A)m
X2 X2
have no effect on stability whatsoever.
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Preferred molecules are those in which the -(B)n-(A)m
substituents on the phenyl or pyridyl groups are
selected from:
-~H3 ; -C2Hs ; -CH2-cH2-cH2-sO3
-CH2CH(OH)CH2SO3- and -SO3-.
Preferably Xl and X2 are Cl, Br or CH3, particularly Cl
or CH3.
Typical examples of preferred Fe(III) and Mn(III)
porphyrins are thus compounds wherein the Ar-
substituents are:
Cl so-3 CH3 SO-3
~ >=< ' '
; ~ - CH3
Cl . CH3
Cl CH3
~ N+ - CH3 ; ~ N+ - CH3
25 Cl CH3
Cl CH3
- CH2 - ~ - CH3 ; ~ -N+ - C2H5
Cl CH3
The metallo-porphyrins of the invention can be used as a
catalyst for peroxyacids or peroxyacid salts for the
bleaching of fabrics in the same manner as applied with
the known metallo-porphyrins of the art, but it can
easily be appreciated that the improved stability
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C 7150 (R)
thereof will result in a more effective and efficient
use of the catalyst.
A common process of using metallo-porphyrins as catalyst
in the bleaching and cleaning of fabrics with peroxy
acid or a peroxyacid salt is by treating the fabrics
with the metallo-porphyrin compound, leaving the fabric
in contact therewith for a predetermined time to effect
sufficient adsorption of said compound on to the fabric,
lo and thereafter washing the fabric with a peroxyacid
bleach composition. The fabrics may be treated in a bath
comprising an effective amount of a dissolved or
solubilised metallo-porphyrin (normally in the range of
2 to 25 ppm) for several minutes, to which bath is then
added a peroxyacid bleaching agent in an amount
sufficient to effect the required bleaching effect
tnormally at a level of about 20-1000 ppm). The amount
of solubilised or dissolved metallo-porphyrin in the
bath and also the amount of~peroxyacid bleach added
thereto will depend upon the fabric wash load and the
rate of staining, the adjustment thereof being within
the ability of the skilled artisan.
An alternative way of pretreating the fabrics is by
manual application on to the fabric on places with
stubborn and persistent stains, and leaving the fabric
treated therewith for a couple of minutes, whereafter
the fabric is washed in a conventional manner with a
peroxyacid bleach composition.
It should be appreciated that the fabrics which are
treated in a bath comprising a dissolved or solubilised
metallo-porphyrin may, or may not, have been manually
pretreated with metallo-porphyrin as is deemed
necessary.
The peroxyacids, the activity of which can be catalysed
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by the metallo-porphyrins of the invention, include any
organic peroxyacids and inorganic peroxyacid salts.
Examples of 6uch organic peroxyacids can be represented
by compounds of the general formula:
P,
HO-O-C-(O)n-R-Y
wherein R is an alkylene or substituted al~ylene group
containing 1 to 20 carbon atoms or an arylene group
containing from 6 to 8 carbon atoms, n i6 0 or 1, and Y
is hydrogen, halogen, alkyl, aryl or any group which
provides an anionic moiety in aqueous solution. Such
groups can include, for example:
O O O
-C-OM ; -C-O-OM or -S-OM
wherein M is H or a water-soluble, salt-forming cation.
The organic peroxyacid~ and salts thereof can contain
either one, two or more peroxy groups and can be either
aliphatic or aromatic. When the organic peroxyacid is
aliphatic, the unsubstituted acid may have the general
formula:
u
HO-O-C-(O)n~(CH2)m~Y
O O
wherein Y can be H, -CH3, -CH2Cl, -C-O-M, C-O-OM
or -S-OM,
O
and m can be an integer from 1 to 20.
.
Specific examples o~ compounds of this type are
peracetic acid, perlauric acid and diperoxydodecanedioic
acid.
When the organic peroxyacid is aromatic, the
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unsubstituted acid may have the general formula:
o
HO-O-c- () n~C6H4~Y
wherein Y is, for example, hydrogen, halogen, alkyl,
O O O
1~ 11 11
-C-QM, -C-O-OM or -S-OM.
The percarboxy or percarbonic and Y groupings can be in
any relative position around the aromatic ring. The ring
and/or Y group (if alkyl) can contain any non-
interfering substituents, 6uch as halogen or sulphonate
groups.
Specific examples of such aromatic peroxyacids and salts
thereof include peroxybenzoic acid, m-chloro-
peroxybenzoic acid, p-nitro-peroxybenzoic acid, p-
sulphonato-peroxybenzoic acid, diperoxyisophthalic acid
and peroxy-alpha-napthoic acid.
A specific example of inorgan~c peroxyacid salts is
potassium monopersulphate. A product comprising this
compound i5 the triple salt, K2S04.KHSO4.2KHSO5,
available commercially under the trade-name Oxone R from
E.I. Dupont de Nemours and Company.
Accordingly, the invention provides the use of a
metallo-porphyrin of structural formula (I), as defined
herein above, as a bleach c~talyst for the bleaching of
fabrics with a peroxyacid bleach ~ystem.
The invention also provides a fabric washing product
comprising a detergent active-material, a peroxyacid
bleach and said metallo-porphyrin as catalyst therefor.
Fabric washing products according to the invention may
be presented in any form, including that of a packages
washing powder comprising the metallo-porphyrin
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catalyst, together with a separate pack of ona-wash
peroxyacid containing sachets.
Alternatively, the product can be in the form of a
sachet within a sachet, the inner sachet containing a
peroxyacid and being provided by means of a delaying
release of the contents, and the outer sachet
containing a washing composition comprising the metallo
porphyrin catalyst and releasing its contents fairly
rapidly upon immersion in water.
Another product form is for example that of a washing
powder compri6ing a peroxyacid and the metallo-porphyrin
catalyst in which the peroxyacid is provided in the
form of coherently coated particles. Still other product
forms are feasible and those skilled in the art will
have no difficulty in selecting product forms by means
of existing technology.
In another embodiment, the invention provides a
pretreatment product for local application on to
fabrics, textiles and clothes, consisting essentially of
a liquid or paste-like composition comprising a
dispersion or solution of a metallo-porphyrin as defined
herein in a 6uitable liquid or semi-liquid carrier,
presented in a suitable di6penser for manual application
of any known form of applicators, such as an aerosol
pres~ure container, pump-spray bottle, roller-ball
capped bottle, pad applicators and the like.
In such applicators the liquid carrier will also contain
a volatile solvent which evaporates upon application,
leaving the metallo-porphyrin firmly attached on to the
fabric surface to absorb. An example of a suitable
carrier is a mixture of a nonionic surfactant and a
lower alcohol, e.g. methanol.
Compositions compri6in~ the metallo-porphyrins of the
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invention dispersed in a carrier of this type are
typical for roller-ball capped bottle and pad
applicators. Liquid or paste-like compositions for use
in a pretreatment product may contain from about 0.1-1.0
g/l metallo~porphyrin, usually from about 0.2-0.5 g/l.
The treating bath as well as the washing composition
comprising the metallo-porphyrin catalyst can contain
any of the usual components of detergent compositions in
the usual amounts. Thus organic detergent-active
materials of the anionic, nonionic, zwitterionic and
cationic types and mixtures thereof can be present, in
an amount from about 3 to about 40% by weight.
Suitable detergent-actives are well known in the art
and examples of such suitable compounds commonly used in
the art are given in "Surface Active Agents", Vol. I, by
Schwartz and Perry (Interscience 1949) and "Surface
Active Agents", Vol. II, by Schwartz, Perry and Berch
~Interscience 1958).
Detergency builders, whether inorganic or organic,
phosphate or non-phosphate, water-soluble or insoluble,
and other water-soluble salts and buffering agents may
preferably also be present. In addition thereto the
washing composition may contain any other non-
interfering ingredients normally used in detergent
compositions in minor amounts, which serve to improve
the bleaching and laundering characteristics of the
composition or which add aesthetic appeal to the
composition. Such minor ingredients can include
sequestering agents and co-builders (e.g. homo- and co-
polymers); suds control agents; soil-suspending agents
and anti-redeposition agents; enzymes, particularly
proteolytic and lipolytic enzymes; corrosion inhibitors,
optical brightening agents, colouring agents, perfumes,
clays and fillers.
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Fabric washing compositions usable in the present
invention may contain from about 3 to about 40% by
weight of organic detergent active material, 0 to 60%,
preferably from 5 to about 40% by weight of detergency
builder, from about 1 to 10% by weight of peroxyacid,
and from about 0.05 to 1.0% by weight of metallo-
porphyrin. They are usable normally at a dosage of 2-10
g/l for washing fabrics at wash loads of about 4-5 kg.
The i~vention will now be illustrated by way of the
following non-limiting examples.
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11
Example I
Preparation of metallo-porphyrins according to the
invention.
(i) Tetrakis-(2,4,6-trimethyl-3-sulphonatophenyl)-
porphyrinato-Mn(III)oH4- (Na~)4
To 2.14 g pyrrole (0.02 mol) and 2.96 g 2,4,6-trimethyl-
lo benzaldehyde solved in 3 1 dichloromethane (dry) i6
added 0.5 ml of boron trifluoride-etherate. After 24 h
stirring under argon in the dark, the mixture is
refluxed for 30 minutes in the presence of 15 g
chloranil (0.06 mol). The mixture is concentrated and
chromatographed on alumina with chloroform as eluent.
The porphyrin-containing fractionc are pooled and
evaporated. From the residue the tetrakis-(2,4,6-
trimethyl phenyl) porphyrin is obtained by
crystallisation from hexane. Treatment of this porphyrin
with concentrated sulphuric acid yields the tetrakis-
(2,4,6-trimethyl-3-sulphonato)-porphyrin as its four
atropisomers. Stirring the latter in aqueous Mn-acetate
(lM), subsequent treatment with ion exchanger (Dowex 50
W-H-form) and final neutralisation yields the compound
(i) which is further purified by chromatography on a
Sephadex L H-20 column in methanol and obtained in a
yield of 0.8 gram (20%).
The system is characterised by its W/VIS, IR and FAB-
massespeatrometry.
(ii) ~etrakis-(2,4,6-trimethyl-3-sulphonatophenyl)-
porphyrinato-Fe(III)OH4~ (Na+)4
This system was prepared in a manner similar to that as
described for (i) above, except that now metalation was
2Gl~)271.
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12
performed using FeS04, ~iving the compound (ii) in a 0.3
gram (7%) yield, similary characterised as described for
the manganese porphyrin.
Exam~le II
The oxidation stability of the substituted mangano-
porphyrin of Example I (i) (TMP4-) against potassium
monopersulphate (HS05-) and peracetic acid (per-Ac) was
determined and compared with a non-substituted mangano-
porphyrin (TPP4-).
Ar-substituents:
CH3 S03- so3
(TMP4 ) = ~ CH3- (TPP4-) =
CH3
Stabilities were measured by means of a UV/VIS
spactroscopic method in the absence of a substrate at
cat~lyst concentration of 10-6 mol/l.
The resu}ts are tabulated below.
Table 1
Stabilitv values from tests with HS05-(3.8 x 10-3 mol/l)
Time (min.) 0 4 8 15 30 60 T ~
TMP4 100 96 92 89 83 75 120.0 minutes
TPP4- 100 63 33 18 - - 5.5 minutes
Table 2
StabilitY values from tests with Per-Ac (2.4 x 10-3
mol/l)
Time (min.) 0 5 10 30 T ~
TMP4- 100 96 94 91 150.0 minutes
TPP4- 100 30 15 - 2.0 minutes
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13
From the above tables it is clearly seen that TMP4 of
the invention is more stable than TPP4- of the art
against peracetic acid and potassium monopersulphate. In
terms of hal~-life time, TMP4- is about 20 times more
stable against HS05- and about 75 times more stable
against peracetic acid than TPP4-.
.
'
