Composition and method for bleaching a substrate

Details Composition and method for bleaching a substrate Composition and method for bleaching a substrate

2001-02-28

2003-08-26

Gupta, Yogendra N. (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

With oxygen or halogen containing chemical bleach or oxidant...

C510S367000

Reexamination Certificate

active

06610641

ABSTRACT:

FIELD OF INVENTION
This invention relates to compositions and methods for catalytically bleaching substrates with a peroxyl species using a defined class of ligand or complex as catalyst.
BACKGROUND OF INVENTION
Peroxygen bleaches are well known for their ability to remove stains from substrates. Traditionally, the substrate is subjected to hydrogen peroxide, or to substances that can generate hydroperoxyl radicals, such as inorganic or organic peroxides. Generally, these systems must be activated. One method of activation is to employ wash temperatures of 60° C. or higher. However, these high temperatures often lead to inefficient cleaning, and can also cause premature damage to the substrate.
A preferred approach to generating hydroperoxyl bleach radicals is the use of inorganic peroxides coupled with organic precursor compounds. These systems are employed for many commercial laundry powders. For example, various European systems are based on tetraacetyl ethylenediamine (TAED) as the organic precursor coupled with sodium perborate or sodium percarbonate, whereas in the United States laundry bleach products are typically based on sodium nonanoyloxybenzenesulphonate (SNOBS) as the organic precursor coupled with sodium perborate.
Precursor systems are generally effective but still exhibit several disadvantages. For example, organic precursors are moderately sophisticated molecules requiring multi-step manufacturing processes resulting in high capital costs. Also, precursor systems have large formulation space requirements so that a significant proportion of a laundry powder must be devoted to the bleach components, leaving less room for other active ingredients and complicating the development of concentrated powders. Moreover, precursor systems do not bleach very efficiently in countries where consumers have wash habits entailing low dosage, short wash times, cold temperatures and low wash liquor to substrate ratios.
It is an object of the present invention to provide an effective bleaching system that functions satisfactorily in the absence or reduced amounts of organic precursor compounds found in commercial laundry products.
SUMMARY OF INVENTION
We have found that a selected class of ligand or complex is surprisingly effective in catalysing the bleaching of substrates using peroxyl species.
Accordingly, the present invention provides a composition comprising a ligand that forms a complex with a transition metal together with at least 1%, preferably at least 5%, of a peroxyl species or equivalent source thereof,
wherein the ligand forms a complex of the general formula (A1):
[M
a
L
k
X
n
]Y
m
  (A1)
 in which:
M represents a metal selected from Mn(II)-(III)-(IV)-(V), Cu(I)-(II)-(III), Fe(II)-(III)-(IV)-(V), Co(I)-(II)-(III), Ti(II)-(III)-(IV), V(II)-(III)-(IV)-(V), Mo(II)-(III)-(IV)-(V)-(VI) and W(IV)-(V)-(VI);
X represents a coordinating species selected from any mono, bi or tri charged anions and any neutral molecules able to coordinate the metal in a mono, bi or tridentate manner;
Y represents any non-coordinated counter ion;
a represents an integer from 1 to 10;
k represents an integer from 1 to 10;
n represents an integer from 1 to 10;
m represents zero or an integer from 1 to 20; and
L represents a ligand of the general formula (I), or its protonated or deprotonated analogue:
 wherein
R
1
, R
2
, and R
3
independently represent a group selected from hydrogen, hydroxyl, halogen, —NH—C(NH)NH
2
, —R and —OR, wherein R=alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E;
Q independently represents a group selected from C
2-3
-alkylene optionally substituted by H, benzyl or C
1-8
-alkyl;
Q
1
, Q
2
and Q
3
independently represent a group of the formula:
 wherein
5≧a+b+c≧1; a=0-5; b=0-5; c=0-5; n=1 or 2;
Y independently represents a group selected from —O—, —S—, —SO—, —SO
2
—, —C (O)—, arylene, alkylene, heteroarylene, heterocycloalkylene, —(G)P—, —P(O)— and —(G)N—, wherein G is selected from hydrogen, alkyl, aryl, arylalkyl, cycloalkyl, each except hydrogen being optionally substituted by one or more functional groups E;
R5, R6, R7, R8 independently represent a group selected from hydrogen, hydroxyl, halogen, —R and —OR, wherein R represents alkyl, alkenyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl or a carbonyl derivative group, R being optionally substituted by one or more functional groups E,
or R5 together with R6, or R7 together with R8, or both, represent oxygen,
or R5 together with R7 and/or independently R6 together with R8, or R5 together with R8 and/or independently R6 together with R7, represent C
1-6
-alkylene optionally substituted by C
1-4
-alkyl, —F, —Cl, —Br or —I; and
E independently represents a functional group selected from —F, —Cl, —Br, —I, —OH, —OR′, —NH
2
, —NHR′, —N(R′)
2
, —N(R′)
3
+
, —C(O)R′, —OC(O)R′, —COOH, —COO
−
(Na
+
, K
+
), —COOR′, —C(O)NH
2
, —C(O)NHR′, —C(O)N(R′)
2
, heteroaryl, —R′, —SR′, —SH, —P(R′)
2
, —P(O)(R′)
2
, —P(O)(OH)
2
, —P(O)(OR′)
2
, —NO
2
, —SO
3
H, —SO
3
−
(Na
+
, K
+
), —S(O)
2
R′, —NHC(O)R′, and —N(R′)C(O)R′, wherein R′ represents cycloalkyl, aryl, arylalkyl, or alkyl optionally substituted by —F, —Cl, —Br, —I, —NH
3
+
, —SO
3
H, —SO
3
−
(Na
+
, K
+
), —COOH, —COO
−
(Na
+
, K
+
), —P(O)(OH)
2
, or —P(O)(O
−
(Na
+
, K
+
))
2
,
provided that at least one, preferably at least two, of R
1
, R
2
and R
3
is a coordinating group.
A present invention also provides a method of bleaching a substrate comprising applying to the substrate, in an aqueous medium, a bleaching composition as defined herein.
The present invention also extends to use of a ligand or complex as defined below in the manufacture of a bleaching composition, the bleaching composition containing effective amounts of a peroxygen bleach or a peroxy-based or peroxy-generating bleach system. An effective amount of a peroxygen bleach may be provided by a composition containing at least 1%, preferably at least 5%, of a peroxyl species. In the present invention, it is preferred that the composition contains the range of about 1-35% by weight, preferably from 5-25% of a peroxyl species.
The present invention also extends to a commercial package comprising a bleaching composition according to the present invention together with instructions for its use.
DETAILED DESCRIPTION OF THE INVENTION
The ligand may be present as a preformed complex of a ligand and a transition metal. Alternatively, the composition may comprise a free ligand that complexes with a transition metal already present in the water or that complexes with a transition metal present in the substrate. The composition may also be formulated as a composition of a free ligand or a transition metal-substitutable metal-ligand complex, and a source of transition metal, whereby the complex is formed in situ in the medium.
The ligand forms a complex with one or more transition metals, in the latter case for example as a dinuclear complex. Suitable transition metals include for example: manganese in oxidation states II-V, iron II-V, copper I-III, cobalt I∝III, titanium II-IV, tungsten IV-VI, vanadium II-V and molybdenum II-VI.
At least two, and preferably at least three, of R
1
, R
2
and R
3
independently represent a group selected from carboxylate, amido, —NH—C(NH)NH
2
, hydroxyphenyl, an optionally substituted heterocyclic ring or an optionally substituted heteroaromatic ring selected from pyridine, pyrimidine, pyrazine, pyrazole, imidazole, benzimidazole, pyrrole, quinoline, quinoxaline, triazole, isoquinoline, carbazole, indole, isoindole, oxazole and thiazole. Preferably, at least two of R
1
, R
2
, R
3
each independently represent a coordinating group selected from optionally substituted pyridin-2-yl,

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