[0001] This invention relates to bleaching compositions comprising peracid precursors, more
particularly acyloxynitrogen peracid precursors. According to the present invention
peroxygen bleach activator compounds that aid in providing efficient peroxygen bleaching
of fabrics over a wide temperature range when combined with a source of hydrogen peroxide
in aqueous media are utilized. These compounds have the general structures:

wherein R is a straight or branched chain C
1-20alkyl, alkoxyl, cycloalkyl and mixtures thereof; R
1 contains at least one carbon atom which is singly bonded directly to N; n is an integer
from 1 to 6 and X is methylene or a heteroatom: or

wherein n is the same as in (I); but R
2 contains a carbon atom doubly bonded directly to N, and, either X is a heteroatom,
R is C
4-
17 alkyl or both.
[0002] It is well known that peroxygen bleaches are effective in removing stains and/or
soils from textiles. They may be used on a wide variety of fabrics and coloured garments.
However, the efficacy of peroxygen bleaches may vary greatly with temperature of the
wash water in which they are used and they are usually most effective when the bleaching
solution is above 130°F (54°C). Below this temperature, it has been found that peroxide
bleaching efficacy may be greatly increased by the simultaneous use of activators,
otherwise known as peracid precursors. It has widely been accepted that in aqueous
media, precursors and peroxygen combine to form peracid species. However, efficacy
of most precursors, such as tetracetylethylene diamine (TAED), is also dependent on
high wash water temperature. However, there is a need for bleach activator or peracid
precursor compounds which are able to react with peroxide efficiently at low temperatures
(70-100° F; 21-38° C) to form peracids in good yields for proper cleaning performance.
[0003] Peracids themselves may be hazardous to make and are particularly prone to decomposition
upon long-term storage. Thus it is advantageous to prepare the more stable peracid
precursor compounds, which in alkaline water solution will react with peroxide anion
to form the desired peracid in situ. As may be seen from the extensive literature
in this area, many such peroxygen activators (peracid precursors) have been proposed.
However, no reference appears to have taught, disclosed or suggested the advantages
of leaving groups containing nitrogen in perhydrolysis.
[0004] Various compounds have been disclosed in the prior art that contain nitrogen as part
of the leaving group of the peroxygen precursors. U.S. Patent Nos. 3,969,257, 3,655,567,
3,061,550 and 3,928,223 appear to disclose the use of acyl groups attached to nitrogen
atoms as leaving groups for activators. In all these examples, the acyl carbon atom
is directly attached to the nitrogen atom. The nitrogen may in turn be attached to
other carbonyl carbon groups.
[0005] In U.S. Patent No. 4,164,395, a sulphonyl group is attached to the nitrogen atom
of the leaving group. The activator structure is thus a sulphonyl oxime.
[0006] U.S. Patent No. 3,975,153 teaches the use of only isophorone oxime acetate as a bleach
activator. It is claimed that this isophorone derivative results in an activator of
low odour and low toxicity. In U.S. Patent No. 3,816,319, the use of diacylated glyoximes
is taught. The use is restricted to diacylated dialkylglyoximes wherein the alkyl
group contains one to four carbon atoms and the acyl group contains two to four atoms.
In neither reference is it disclosed, taught or suggested that it is surprisingly
necessary to provide a heteroatom alpha to the carbonyl of the acyl group if a peracid
precursor contains oxime as a leaving group. Additionally, neither reference discloses
the unique advantages conferred by surface active peracid precursors which contain
about 4-14 carbons in the acyl group.
[0007] In one embodiment, the present invention relates to a bleaching composition comprising:
(a) a peracid precursor having the general structure:

wherein R is a straight or branched chain Cl-2oalkyl, alkoxyl, cycloalkyl and mixtures thereof; R1 contains at least one carbon atom which is singly bonded directly to N; n is an integer
from 1 to 6 and X is methylene or a heteroatom; or

wherein n is the same as in (I); but R2 contains a carbon atom doubly bonded directly to N, and either X is a heteroatom,
R is C4-17 alkyl or both; and
(b) a bleach-effective amount of a source of hydrogen peroxide.
[0008] The complete precursor (an ester) is

wherein R is a straight or branched chain C
l-
20alkyl, alkoxyl, cycloalkyl and mixtures thereof; R contains at least one carbon atom
which is singly bonded directly to N, n is an integer from 1 to 6 and X is methylene
or a heteroatom; or (II) R-X-(CH
2)
n .-O-N=R
2,
wherein n is the same as in (I); but R contains a carbon atom doubly bonded directly
to N, and, either X is a heteroatom, R is C
4-
17 alkyl or both.
[0009] It is preferred that R is C1-2c alkyl or alkoxylated alkyl. More preferably, R is
C
4-
17, and mixtures thereof. R may also be mono- or poly-unsaturated. If alkoxylated, ethoxy
(EO) -(-OCH
2CH
2) and propoxy (PO) -(-OCH
2CH
2CH
2) groups are preferred, and may be present, per mole of ester, from 1 to 30 EO or
PO groups, and mixtures thereof.
[0010] It is preferred for R to be from 4 to 17, and especially from 6 to 12, carbons in
the alkyl chain. Such alkyl groups would be surface active and would be desirable
when the precursor is used to form surface active peracids for oxidizing fat or oil
based soils from substrates at relatively low temperatures.
[0011] These alkyl groups are generally introduced onto the ester via an acid chloride synthesis
discussed further below. Fatty acid chlorides such as hexanoyl chloride, heptanoyl
chloride, octanoyl chloride, nonanoyl chloride and decanoyl chloride, provide this
alkyl moiety. When it is desired to introduce an aryl group, an aromatic acid chloride
may be used, such as phenoxyacetyl chloride, although this is the subject of concurrently
filed application..... entitled "Peroxyacids, Phenoxyacetate Peracid Precursors and
Perhydrolysis Systems", (based on USSN 927,856 and USSN 45,197).
[0012] Also, in the above generic structures for the present precursors, when n is 1, X
is at the alpha-position to the terminal carbonyl group. In the present invention,
under certain circumstances, such as when the nitrogen of the oxynitrogen bond is
itself double bonded to a carbon atom (structure (II)), forming an oxime, X is O,
oxygen. X, however, could also be another electronegative atom, such as -S-(sulphide),
-N-(amine) or even -NH 4 - (quaternary ammonium). In accordance with the present invention,
however, it is most preferable that X is O (oxygen), or methylene.
[0013] As mentioned, n = 1 to 6 carbylene substituents, but n = 1 to 3 is more preferred,
and most preferably n does not exceed about 2.
[0014] When n = 1 or 2, the base carbonyl is an acetic acid or propionic acid derivative.
The acetic acid derivatives have been found surprisingly effective and are discussed
in two concurrently filed applications ..... and .... entitled "Bleaching Compositions,
Glycolate Ester Peracids and Precursors", and "Peroxyacids, Phenoxyacetate Peracid
Precursors and Perhydrolysis Systems" (based on USSN 928,070 and USSN 927,856/USSN
45,197, respectively.)
[0015] When the heteroatom, X is O (oxygen), and n is 1, the effect of an electronegative
substituent alpha to the terminal carbonyl enhances the reactivity of the present
precursors.
[0016] The electronic effect of this modification at the proximal methylene group (when
n = 1) appears to make the carbonyl group more susceptible to nucleophilic attack
by a perhydroxide anion. The resulting enhanced reactivity results in higher peracid
yields at low temperatures (e.g., 70° F; 21 ° C), across a broader pH range, and makes
the perhydrolysis reaction to generate peracids less susceptible to critical activator
to H
20
2 ratios. However, in another embodiment, when the leaving group of the precursor is
structure (I), -ONR1, it is preferred that X is methylene. As a representative example,
the octanyl group,

does not contain any heteroatoms within the alkyl chain.
[0017] In the following discussion, certain definitions are utilized:
Peracid precursor is generally equivalent to bleach activator. Both terms generally
relate herein to reactive esters which have a leaving group substituent, which during
perhydrolysis, actually cleave off the acyl portion of the ester.
[0018] Perhydrolysis is the reaction which occurs when a peracid precursor or activator
is combined in a reaction medium (aqueous medium) with an effective amount of a source
of hydrogen peroxide.
[0019] The leaving group is basically a substituent which is attached via an oxygen bond
to the acyl portion of the ester and which may be replaced by a perhydroxide anion
(OOH-) during perhydrolysis.
[0020] The basic reaction is:

→

[0021] The present invention utilises, in particular, oxynitrogen leaving groups having
the general structures (I)-ONR
1 and (II) -ON=R
2 which are attached to an acvl.

, group to form the peracid precursors in accordance with the present invention. These
leaving groups have an oxygen atom attached to nitrogen which in turn may be attached
to carbon atoms in a variety of structural configurations. The oxygen of the leaving
group is attached directly to the carbonyl carbon to form the intact precursor.
[0022] When considering the activator structures below

there are at least two different types of structure for the R group and there is at
least one type of structure for the R
2 group.
[0023] The first preferred structure for R is where the nitrogen atom is attached to two
carbonyl carbon groups.
[0024] The leaving group then would be an oxyimide group :

wherein R3 and R4 may be the same or different, and are preferably straight chain
or branched C
1-20 alkyl, aryl, alkylaryl or mixtures thereof. If alkyl, R
3 and R
4 may be partially unsaturated. It is especially preferred that R
3 and R
4 are straight or branched chain C
1-
6 alkyls, which may be the same or different. R
5 is preferably C
1-
20alkyl, aryl or alkylaryl, and completes a heterocycle. R
5 includes the preferred structure:

wherein R
6 may be an aromatic ring fused to the heterocycle, or C
1-6 alkyl.
[0025] Thus, these leaving group structures could contain an acyclic or cyclic oxyimide
moiety. The above precursor may be seen as a combination of a carboxylic acid and
a hydroxyimide compound:

[0026] These esters of imides may be prepared as described in Greene, Protective Groups
in Organic Synthesis, p. 183, and are generally the reaction products of acid chlorides
and hydroxyimides.
[0027] Examples of N-hydroxyimides which will provide the oxyimide leaving groups in accordance
with the present invention includes:
N-hydroxysuccinimide, N-hydroxyphthalimide, N-hydroxyglutarimide, N-hydroxynaphthalimide,
N-hydroxyma- leimide, N-hydroxydiacetylimide and N-hydroxydipropionylimide.
[0028] Especially preferred examples of oxyimide leaving groups are:

[0029] When treated with peroxide anion, a peracid is formed and the leaving group departs
with oxygen attached to nitrogen and a negative charge on the oxygen atoms. The pKa
(about 6) of the resulting hydroxyimides is quite low, making them excellent leaving
groups.
[0030] The second preferred structure for R is where the nitrogen atom is attached to at
least two carbons. These are amine oxide leaving groups, comprising:

[0031] In the first preferred structure for amine oxides, R
8 and R
9 may be the same or different, and are preferably Ci-
20 straight or branched chain alkyl, aryl, alkylaryl or mixtures thereof. If alkyl,
the substituent may be partially unsaturated. Preferably, R
8 and R
9 are C
1-4alkyls and may be the same or different. R
10 is preferably C
1-30 alkyl, aryl, alkylaryl and mixtures thereof. This R
10 substituent may also be partially unsaturated. It is most preferred that R
8 and R
9 are relatively short chain alkyl groups (CH
3 or CH
2CH
3) and R
10 is preferably C
1-20 alkyl, forming together a tertiary amine oxide.
[0032] Furthermore, in the second preferred amine oxide structure, R
11 may be C
1-20 alkyl, aryl or alkylaryl, and completes a heterocycle. R
11 preferably completes an aromatic heterocycle of 5 carbon atoms and may be C
1-6alkyl or aryl substituted. R
12 is preferably nothing, C
1-30 alkyl, aryl, alkylaryl or mixtures thereof. R
12 is more preferably C
1-
20 alkyl if R
11 completes an aliphatic heterocycle. If R
11 completes an aromatic heterocycle, R
12 is nothing.
[0033] This type of structure is really a combination of a carboxylic acid and an amine
oxide:

[0034] Amine oxides may be prepared as described in March, Advanced Organic Chemistry, 2d
Ed., 1977, p.1,111.
[0035] Examples of amine oxides suitable for use as leaving groups may be derived from:
pyridine N-oxide, trimethylamine N-oxide, 4-phenyl pyridine N-oxide, decyldimethylamine
N-oxide, dodecyldimethylamine N-oxide, tetradecyldimethylamine N-oxide, hexadecyldimethylamine
N-oxide, octyldimethylamine N-oxide, di(decyl)methylamine N-oxide, di(dodecyl)methylamine
N-oxide, di(tetradecyl)methylamine N-oxide, 4-picoline N-oxide, 3-picoline N-oxide
and 2-picoline N-oxide.
[0036] Especially preferred amine oxide leaving groups include:

[0037] When the precursor is attacked by peroxide anion, a peracid is formed and the leaving
group leaves as an amine oxide, again with oxygen attached to nitrogen and the negative
charge on the oxygen.
[0038] When the oxynitrogen leaving group is structure (II) -ON = R2, preferred examples
thereof are oximes.
[0039] In these oxime leaving groups, the nitrogen atom is attached to a carbon atom via
a double bond.

wherein R
13 and R
14 are individually H, C
1-20 alkyl, (which may be cycloalkyl, straight or branched chain), aryl, or alkylaryl.
Preferably R
13 and R
14 are the same or different and range from C
1-6; and at least one of R
13 and
R14 is not H.
[0040] The structure of an oxime ester of a carboxylic acid may be broken down into two
parts:

[0041] As mentioned above, since R
2 comprises carbon double bonded directly to the nitrogen of the oxynitrogen bond,
either (a) the R group of the acyl is preferably C
4-
17, more preferably Ce-i
2, alkyl (resulting in a surface active ester) or (b) X, the heteroatom is oxygen and
the carbylene number, n, is 1, or (c) both conditions may occur.
[0042] An examDle of (a) is octanovloxv dimethvl oxime ester.

[0043] An example of (b) is hexanoxy acetyl dimethyl oxime ester,

[0044] Oximes are generally derived from the reaction of hydroxylamines with either aldehydes
or ketones (Allinger et al, Organic Chemistry, 2d Ed., p.562 (1976), both of which
are within the scope of the present invention. Examples of an oxime leaving group
are: (a) oximes of aldehydes (aldoximes), e.g., acetaldoxime, benzaldoxime, propionaldoxime,
butylaldoxime, heptaldoxime, phenylacetaldoxime, p-tolualdoxime, anisal- doxime, caproaldoxime,
valeraldoxime and p-nitrobenzaldoxime; and (b) oximes of ketones (ketoximes), e.g.,
acetone oxime (2-propanone oxime), methyl ethyl ketoxime (2-butanone oxime), 2-pentanone
oxime, 2-hexanone oxime, 3-hexanone oxime, cyclohexanone oxime, acetophenone oxime,
benzophenone oxime, and cyclopentanone oxime.
[0045] Particularly preferred oxime leaving groups are:

[0046] When attacked by peroxide anion, the oxime ester forms a peracid and the oxime becomes
the leaving group. It is rather surprising that the oximes are such good leaving groups
since their pKa values (about 12) are rather high for a good leaving group. Previous
experience teaches that leaving groups with pKa values for their conjugate acids in
the 8-10 range make the best leaving groups. Although there are examples in the prior
art of oxime esters (U.S. Patent Nos. 4,164,395 and 3,975,153), in fact, no mention
is made that a heteroatom alpha to the carbonyl group on the acyl portion of the ester
is necessary for good perhydrolysis yields; or that if the R group of the acyl is
C4-1 alkyl, more preferably Cs-
1 2alkyl, surface active peracid precursors giving rise to surface active peracids will
result.
[0047] The present precursors may be incorporated into a liquid or solid matrix for use
in liquid or solid detergent bleaches by dissolving into an appropriate solvent or
surfactant or by dispersing liquid or liquified precursors onto a substrate material,
such as an inert salt (e.g., NaCl, Na
2SO
4) or other solid substrate, such as zeolites, sodium borate, or molecular sieves.
Examples of appropriate solvents include acetone, non-nucleophilic alcohols, ethers
or hydrocarbons.
[0048] Other more water-dispersible or -miscible solvents may be considered. As an example
of affixation to a substrate material, the present precursors could be incorporated
onto a non-particulate substrate such as disclosed in published European Patent Application
EP 98 129.
[0049] The present precursors with oxynitrogen leaving groups are apparently not as soluble
in aqueous media as phenyl sulphonates. Thus, a preferred embodiment of the present
invention is to combine the precursors with a surfactant. It is particularly preferred
to coat these precursors with a nonionic or anionic surfactant that is solid at room
temperature and melts at above about 40° C. A melt of surfactant may be simply admixed
with peracid precursor, cooled and chopped into granules. Exemplary surfactants for
such use are illustrated in Table I below:

[0050] The precursors, whether coated with the surfactants with melting completion temperatures
above about 40°C or not so coated, could also be admixed with other surfactants to
provide, depending on formulation, either bleach additive or detergent compositions.
[0051] Particularly effective surfactants appear to be nonionic surfactants. Preferred surfactants
for use include linear ethoxylated alcohols, such as those sold by Shell Chemical
Company under the brand name Neodol. Other suitable nonionic surfactants may include
other linear ethoxylated alcohols with an average length of 6 to 16 carbon atoms and
averaging about 2 to 20 moles of ethylene oxide per mole of alcohol; linear and branched,
primary and secondary ethoxylated, propoxylated alcohols with an average length of
about 6 to 16 carbon atoms and averaging 0-10 moles of ethylene oxide and about 1
to 10 moles of propylene oxide per mole of alcohol; linear and branched alkylphenoxy
(polyethoxy) alcohols, otherwise known as ethoxylated alkylphenols, with an average
chain length of 8 to 16 carbon atoms and averaging 1.5 to 30 moles of ethylene oxide
per mole of alcohol; and mixtures thereof.
[0052] Further suitable nonionic surfactants may include polyoxyethylene carboxylic acid
esters, fatty acid glycerol esters, fatty acid and ethoxylated fatty acid alkanolamides,
certain block copolymers of propylene oxide and ethylene oxide, and block polymers
of propylene oxide and ethylene oxide with propoxylated ethylene diamine. Also included
are such semi-polar nonionic surfactants as amine oxides, phosphine oxides, sulphoxides,
and their ethoxylated derivatives.
[0053] Anionic surfactants may also be suitable. Examples of such anionic surfactants may
include the ammonium, substituted ammonium (e.g., mono-, di-, and triethanolammonium),
alkali metal and alkaline earth metal salts of C
6-C
20 fatty acids and rosin acids, linear and branched alkyl benzene sulphonates, alkyl
sulphates, alkyl ether sulphates, alkane sulphonates, olefin sulphonates, hydroxyalkane
sulphonates, fatty acid monoglyceride sulphates, alkyl glyceryl ether sulphates, acyl
sarcosinates and acyl N-methyltaurides.
[0054] Suitable cationic surfactants may include the quaternary ammonium compounds in which
typically one of the groups linked to the nitrogen atom is a C
12-C
18 alkyl group and the other three groups are short chained alkyl groups which may bear
inert substituents such as phenyl groups.
[0055] Furthermore, suitable amphoteric and zwitterionic surfactants which contain an anionic
water-solubilizing group, a cationic group and a hydrophobic organic group may include
amino carboxylic acids and their salts, amino dicarboxylic acids and their salts,
alkylbetaines, alkyl aminopropylbetaines, sulphobetaines, alkyl imidazolinium derivatives,
certain quaternary ammonium compounds, certain quaternary phosphonium compounds and
certain tertiary sulphonium compounds. Other examples of potentially suitable zwitterionic
surfactants may be found described in U.S. Patent No. 4,005,029, at columns 11-15.
[0056] Further examples of anionic, nonionic, cationic and amphoteric surfactants which
may be suitable for use in accordance with the present invention are depicted in Kirk-Othmer,
Encyclopedia of Chemical Technology,Third Edition, Volume 22, pages 347-387, and McCutcheon's
Detergents and Emulsifiers, North American Edition, 1983.
[0057] As mentioned above, other common detergent adjuncts may be added if a bleach or detergent
bleach product is desired. If, for example, a dry bleach composition is desired, the
following ranges (weight
0/
0) appear practicable:
0.5-50.0% Hydrogen Peroxide Source
0.05-25.0% Precursor
1.0-50.00/0 Surfactant
1.0-50.00/0 Buffer
5.0-99.9% Filler, stabilizers, dyes, fragrances, brighteners, etc.
[0058] The hydrogen peroxide source may be selected from the alkali metal salts of percarbonate,
perborate, persilicate and hydrogen peroxide adducts and hydrogen peroxide. Most preferred
are sodium percarbonate, sodium perborate mono- and tetra-hydrate, and hydrogen peroxide.
Other peroxygen sources may be possible, such as monopersulphates and monoperphosphates.
In liquid applications, liquid hydrogen peroxide solutions are preferred, but the
precursor may need to be kept separate therefrom prior to combination in aqueous solution
to prevent premature decomposition.
[0059] The range of peroxide to peracid precursor is preferably determined as a molar ratio
of peroxide to ester groups contained in the precursor. Thus, the range of peroxide
to each ester group is preferably a molar ratio of from about 0:5 to 10:1, more preferably
about 1:1 to 5:1 and most preferably about 1:1 to 2:1. It is preferred that this peracid
precursor/peroxide composition provide preferably about 0.5 to 100 ppm A.O., and most
preferably about 1 to 50 ppm A.O., and most preferably about 1 to 20 ppm A.O., in
aqueous media.
[0060] A description and explanation of A.O. measurement is to be found in the article of
Sheldon N. Lewis, "Peracid and Peroxide Oxidations", In: Oxidation, 1969, pp. 213-258.
Determination of the peracid may be ascertained by the analytical techniques taught
in Organic Peracid, (Ed. by D. Swern), Vol. 1, pp. 501 et seq. (CH.7) (1970).
[0061] An example of a practical execution of a liquid delivery system is to dispense separately
metered amounts of the precursor (in some non-reactive fluid medium) and liquid hydrogen
peroxide in a container such as described in U.S. Patent No. 4,585,150.
[0062] A buffer may be selected from sodium carbonate, sodium bicarbonate, sodium borate,
sodium silicate, phosphoric acid salts, and other alkali metal/alkaline earth metal
salts known to those skilled in the art. Organic buffers, such as succinates, maleates
and acetates may also be suitable for use. It appears preferable to have sufficient
buffer to attain an alkaline pH, i.e., above at least about 7.0, more preferably above
about pH 9.0, and most preferably above about pH 10.0.
[0063] The filler material, which, in a detergent bleach application, may actually constitute
the major constituent, by weight, of the detergent bleach, is usually sodium sulphate.
Sodium chloride is another potential filler. Dyes include anthraquinone and similar
blue dyes. Pigments, such as ultramarine blue (UMB), may also be used, and may have
a bluing effect by depositing on fabrics washed with a detergent bleach containing
UMB. Monastral colourants are also possible for inclusion. Brighteners, such as stilbene,
styrene and styrylnaphthalene brighteners (fluorescent whitening agents), may be included.
Fragrances used for aesthetic purposes. are commercially available from Norda, International
Flavors and Fragrances and Givaudon. Stabilizers include hydrated salts, such as magnesium
sulphate, and boric acid.
[0064] In one of the preferred embodiments in which a compound such as in (I) below is the
precursor, a preferred bleach composition has the following ingredients:

[0065] In another of the preferred embodiments, in which a compound as in (II) below is
the precursor, a preferred bleach composition has the following ingredients:

[0066] Other peroxygen sources, such as sodium perborate monohydrate or sodium percarbonate
are suitable. If a more detergent-type product is desired, the amount of filler may
be increased and the precursor halved or further decreased.
EXPERIMENTAL
[0067] The oxime esters may be prepared by treatment of an oxime with the acid chloride
of the corresponding carboxylic acid. In order to have a liquid reaction medium, a
non-reactive solvent is added, and a base.
[0068] The oximes may be purchased or prepared by treatment of a carbonyl compound with
hydroxylamine. Two oximes, acetone oxime and methyl ethyl ketone oxime are readily
available from commercial sources and are inexpensive.
EXAMPLE I
Preparation of Acetone Oxime Ester of Octanoic Acid
[0069]

[0070] A 500 ml three-neck flask was fitted with a paddle stirrer, condenser and dry tube,
and lowered into an oil bath. To the flask was added THF (100 ml), acetone oxime (15g,
0.21 mole), pyridine (16.5 ml, 0.21 mole), and then octanoyl chloride (35 ml, 0.21
mole) in THF (50 ml), dropwise, with rapid stirring. A white solid (pyridine hydrochloride)
precipitated from the solution. The reaction was allowed to stir in an oil bath at
a temperature of 50° C for three hours. The reaction mixture was filtered and the
solvent therein removed via roto-evaporator to give an orange oil (38.8g).
[0071] Thin layer chromatography analysis (silica gel, HX-ETAC, 80-20) of the crude product
showed one main spot (1
2 visualization) at R
f=.47, a small spot at R
f=.90 and a spot at the origin, probably pyridine hydrochloride. The crude product
was placed on a column of silica gel (125g, 230-400 mesh, 4cm D x 25 cm H) and eluted
with HX-ETAC (80-20). The fractions were monitored by TLC, the appropriate ones combined
and solvent removed. In this way, 37.8g of a colourless oil was obtained.
[0072] The infrared spectrum of the oil gave a very strong carbonyl at 1768 cm-
1 and showed no sign of hydroxyl, acid chloride, or carboxylic acid. The
13C-NMR (CDCI
3, ppm downfield from TMS) showed only absorptions expected for the product. Using
the numbering system shown, these assignments are made:

C
7(168.3), Ca(160.9), C
3(29.9), C
6(30.8), C
4(27.2), Cs(23.0), C
2(20.7), C
9(19.6), C
10(12.0), and C↑(14.5). The acyloxyimides may be readily prepared by the treatment of
a hydroxyimide with an acid chloride. While the acid chlorides are readily, commercially
available, the hydroxyimides are not so commercially available.
EXAMPLE 11
Preparation of Octanoyloxy Succinimide
[0073]

[0074] A 500 ml three-neck flask was fitted with double stirrer, condenser with drying tube,
and lowered into an oil bath. To the flask was added THF (175 ml), the N-hydroxysuccinimide
(9.5 g, 0.083 mole) and pyridine (6.7 ml, 0.083 mole). Octanoyl chloride (14.2 ml,
0.083 mole) was dissolved in THF (50 ml) and added to the reaction vessel over a period
of 15 minutes. A white precipitate (pyridine hydrochloride) formed. The reaction mixture
was heated at about 60° C for 3 hours, filtered, the solvent removed via roto-evaporator
to give a light yellow oil (18.9g), which subsequently solidified.
[0075] Thin-layer chromatography analysis (silica gel, CH
2CI
2) of the crude oil showed a main spot at R
f = .60 (UV visualization), a small spot at R
f = .95 and a spot at the origin (pyridine hydrochloride). The crude product was placed
on a column of silica gel (150g, 230-400 mesh, 4 cm diameter x 30 cm tall) and eluted
with methylene chloride. The fractions were monitored by TLC, the appropriate ones
combined, and the solvent removed. Thus, a white solid (15.2 g, 760/o yield) of m.p.
60.5-61.0°C was obtained.
[0076] The infrared spectrum of this solid gave a very strong broad carbonyl at 1735 cm-
1 and sharp ones at 1790 and 1822 cm-
1. The
13C-NMR (CDCI
3) was very clean, showing only those absorptions necessary for the product. Thus it
showed ester carbonyl carbon at 169.5 (ppm downfield from TMS), imide carbonyl at
170.0 and the methylene and methyl carbons at 14.0-31.6 ppm. Analysis of the solid
by saponification number gave a purity of 1000/0.
[0077] The acyl oxy ammonium chloride type compounds MAY be prepared by treatment of an
amine oxide with an acid chloride. Both amine oxides and acid chlorides are readily
available commercially so this should provide for a large variety of practical precursors.
However, the product appears to be formed as a nice solid only when certain high molecular
weight amine oxides are used. Unless care is taken in selecting the reaction conditions
and the reagents, the reaction may at times form oils.
EXAMPLE III
Preparation of Octanoyloxy Ester of 4-Phenylpyridine Oxide
[0078]

A 500 ml three-neck flask was fitted with a paddle stirrer, drying tube, and flushed
with nitrogen.
[0079] To the flask was added THF (150 ml) and 4-phenylpyridine N-oxide (5g, 0.029 mole).
A light yellow solution resulted. To this was added rapidly octanoyl chloride (5.0
ml, 0.029 mole) in THF (20 ml). The mixture was stirred very rapidly for 1
1/
2 minutes. A gelatinous precipitate formed almost immediately. When the viscous solution
was diluted with ether (about 300 ml), a white solid layer separated. The mix was
filtered to give a white solid which was washed with ether. The dried white solid
(7.0 g, 72% yield) had a carbonyl absorption at 1822 cm-
1 in the infrared spectrum. The
13C-NMR was very clean and showed only those absorptions necessary for the product.
A carbonyl at 174.5 (DMSO solvent, ppm downfield from TMS) was observed in addition
to absorptions for the aromatic carbons and those for the alkyl chain.
[0080] When treated with alkaline, aqueous peroxide anion, the precursors described formed
peracids in solution. The table below summarizes the perhydrolysis yields of typical
precursors.

[0081] A comparison of item 5 with all the others, shows the importance of having the oxygen
atom attached directly to nitrogen atom of the leaving group, in accordance with the
teachings of the present invention.
1. A bleaching composition characterised in that it comprises:
(a) a peracid precursor corresponding to the following general formula:

wherein R represents C1-C20 alkyl, alkoxyl, or cycloalkyl; R represents a group which contains at least one carbon
atom which is singly bonded directly to N; n represents an integer of from 1 to 6;
and X represents methylene or a heteroatom; or

,
wherein n is as defined above; R2 represents a group which contains a carbon atom doubly bonded directly to N, and,
either X represents a heteroatom, R represents C4-C17 alkyl, or both;
(b) a bleach-effective amount of a source of hydrogen peroxide; and, optionally,
(c) an adjunct selected from surfactants, builders, fillers, enzymes, fluorescent
whitening agents, pigments, dyes, fragrances, stabilizers and buffers.
2. A bleaching composition as claimed in claim 1 wherein the peracid precursor (I)
comprises a leaving aroup -O-N-R
1 which is either

wherein R
3 and R
4 independently represent C
1-C
20 alkyl, aryl or alkylaryl; and R
5 represents C
1-C
20 alkyl, aryl or alkylaryl and completes a heterocycle; or

wherein R
8 and R
9 independently represent C
1-C
20 alkyl, aryl or alkylaryl; R
10 represents C
1-C
30 alkyl, aryl or alkylaryl; R
11 represents C
1-C
20 alkyl, aryl, alkylaryl and completes a heterocycle; and R
12 represents nothing, C
1-C
20 alkyl, aryl or alkylaryl.
3. A bleaching composition as claimed in claim 1 or claim 2 wherein R represents C6-C12 alkyl, X represents methylene, and n represents 1.
4. A bleaching composition as claimed in claim 2 or claim 3 wherein the leaving group
is (a) and the precursor is an oxyimide ester.
5. A bleaching composition as claimed in claim 4wherein the precursor has the leaving
group:

wherein R
6 represents methylene, an aromatic ring fused to the heterocycle, or C
1-C
6 alkyl.
6. A bleaching composition as claimed in any of claims 1 to 5 wherein the precursor
is:

or
7. A bleaching composition as claimed in claim 2 or claim 3 wherein the leaving group
is (b) and the precursor is an amine oxide ester.
8. A bleaching composition as claimed in claim 7 wherein the precursor has the leaving
group:

wherein R
1 completes an aromatic heterocycle and R
12 represents nothing.
9. A bleaching composition as claimed in claim 8 wherein the precursor is:
10. A bleaching composition as claimed in claim 1 or claim 2 wherein X represents
oxygen and n represents 1.
11. A bleaching composition as claimed in claim 1 wherein the peracid precursor (II)
comprises a leaving group -ON = R
2 which is:

wherein R
13 and R
14 independently represent H, C
1-C
20 alkyl, aryl or alkylaryl, not both R
13 and R
14 representing H; and (a) R represents C
4-C
17 alkyl, (b) X represents oxygen and n represents 1, or (c) both.
12. A bleaching composition as claimed in claim 11 wherein R represents Cs-C12 alkyl, and R13 and R14 independently represent H or C1-C6 alkyl.
13. A bleaching composition as claimed in claim 11 or claim 12 wherein the precursor
is an oxime ester in accordance with (a):

or in accordance with (b):

14. A bleaching composition as claimed in any of claims 1 to 13 wherein the source
of hydrogen peroxide (b) is selected from hydrogen peroxide, hydrogen peroxide adducts,
alkali metal and alkaline earth metal perborates.
15. A bleaching composition as claimed in claim 14 wherein the hydrogen peroxide source
is an alkali metal perborate selected from the mono- and tetra-hydrate forms of sodium
perborate.
16. A bleaching composition as claimed in any of claims 1 to 15 wherein the molar
ratio of hydrogen peroxide source to precursor is from 0.5:1 to 10:1, based on moles
of H202:moles of ester.
17. A bleaching composition as claimed in any of claims 1 to 16 wherein the precursor
(a) is coated with a surfactant having a melting completion temperature above about
40° C.
18. A process for the production of a bleaching composition as defined in any of claims
1 to 17 characterised in that it comprises mixing the constituents.
19. A process for bleaching characterised in that it comprises contacting a material
to be bleached with a bleaching composition as defined in any of claims 1 to 17 in
aqueous medium.