Note: Descriptions are shown in the official language in which they were submitted.
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A PROCESS EMPLOYING AN AMINE OXIDE / ACID PREMIX
FOR MAKING LAUNDRY DETERGENT COMPOSITIONS
BACKGROUND
In societies where mechanical washing machines are not common,
laundry detergent bars comprising synthetic organic surfactants and
detergency builders are used in the laundering of clothes. Synthetic laundry
bars typically comprise a synthetic anionic surfactant such as the alkali
metal
salt of an alkyl benzene sulfonic acid or alkali metal salt of an alkyl
sulfate and
one or more alkaline builders such as alkali metal polyphosphates, carbonates
or silicates.
Technical developments in the field of laundry detergent bars have
concerned formulating bars which are effective in cleaning clothes; which have
acceptable sudsing characteristics in warm and cool water and in hard and soft
water; which have acceptable in-use wear rates, hardness, durability, and
feel;
which have low smear; and which have a pleasing odor and appearance.
Methods for making laundry detergent bars are also well known in the art.
Known laundry bars and methods for making laundry bars include those
disclosed in: U.S. Patent 3,178,370 (Okenfuss, issued April 13, 1965); and
Philippine Patent 13,778 (Anderson, issued September 23, 1980).
Amine oxide surfactants are commonly used in liquid cleaning
compositions to boost and maintain suds formation, andlor improve cleaning,
and/or improve mildness to skin. Such compositions include, for example,
laundry and dishwashing detergent compositions. However, while a laundry
cleaning product formula can be very effective in delivering desired
attributes, it
may not qualify as a usable product if it also has serious processability
problems. For example, the addition of high active (solid or paste) or dilute
(liquid) form amine oxides have proven difficult to properly incorporate into
a
solid detergent composition. Even if such amine oxides are successfully
incorporated, the final product lacks acceptable physical properties.
Based on the foregoing, there is a need for a laundry detergent bar
which comprises an amine oxide, yet maintains acceptable physical properties;
as well as a process for making such a laundry detergent bar composition.
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SUMMARY
The present invention relates to a process for making a solid laundry
detergent containing one or more amine oxide surfactants. The process
comprises mixing an amine oxide component and an acid to form a premix;
mixing the premix, an anionic surfactant and an alkali salt. In the case of a
laundry detergent bar, the resulting composition is formed into a bar. In the
case of a granular laundry detergent, the resulting composition is formed into
granules.
The present invention further relates to a product made by the subject
process.
The present invention further relates to a composition consisting
essentially of an amine oxide and an acid, for use in the subject process.
These and other features, aspects, and advantages of the present
invention will become evident to those skilled in the art from a reading of
the
present disclosure.
DETAILED DESCRIPTION
While the specification concludes with claims which particularly point out
and distinctly claim the invention, it is believed the present invention will
be
better understood from the following description.
All cited references are incorporated herein by reference in their
entireties. Citation of any reference is not an admission regarding any
determination as to its availability as prior art to the claimed invention.
All percentages are by weight of total composition unless specifically
stated otherwise.
All ratios are weight ratios unless specifically stated otherwise.
Herein, "alkenyl" means a carbon-containing chain, preferably from
about C10 to about C20, more preferably from about C12 to about Clg, more
preferably still from about C12 to about Clg; which may be straight, branched
or cyclic, preferably branched or straight, more preferably straight;
substituted
(mono- or poly-) or unsubstituted; and monounsaturated (i.e., one double or
triple bond in the chain), or polyunsaturated (i.e., two or more double bonds
in
the chain, two or more triple bonds in the chain, or one or more double and
one
or more triple bonds in the chain), preferably monounsaturated
Herein, "alkyl" means a carbon-containing chain, preferably from about
C10 to about C20, more preferably from about C12 to about Clg, more
preferably still from about C12 to about Clg; which may be straight, branched
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or cyclic, preferably straight or branched, more preferably straight;
substituted
(mono- or poly-) or unsubstituted; and saturated.
Herein, "comprising" means that other steps and other ingredients which
do not affect the end result can be added. This term encompasses the terms
"consisting of and "consisting essentially of'.
Herein, "coconut oil" is used in connection with materials with fatty acid
mixtures which typically are linear and have an approximate carbon chain
length distribution of about 8% Cg, 7% Clp, 48% C12, 17% C14, 9% Clg, 2%
Clg, 7% oleic, and 2% linoleic (the first six fatty acids listed being
saturated).
Other sources having similar carbon chain length distribution in their fatty
acids,
such as palm kernel oil and babassu oil, are included within the term coconut
oil.
Herein, "LAS" means linear alkyl benzene sulfonate.
Herein, "solid laundry detergent" means a granular laundry detergent or
a laundry detergent bar.
Herein, "tallow" is used in connection with materials with fatty acid
mixtures which typically are linear and have an approximate carbon chain
length distribution of 2% C14, 29% Clg, 23% Clg, 2% palmitoleic, 41% oleic,
and 3% linoleic (the first three fatty acids listed are saturated). Other
mixtures
with similar distribution, such as those from palm oil and those derived from
various animal tallow and lard, are also included within the term tallow. The
tallow can also be hardened (i.e., hydrogenated) to convert part or all of the
unsaturated fatty acid moieties to saturated fatty acid moieties.
In accordance with the present invention, it has been found that a new
process in manufacturing laundry detergent compositions (e.g., bars or
granules) containing an amine oxide component minimizes the creation of any
undesired physical properties otherwise associated with other methods of
incorporating an amine oxide component into such a composition. This new
process employs premixing an amine oxide and an acid. Specifically, the
process of the present invention comprises mixing an amine oxide and an acid
to form a premix; mixing the premix, an anionic surfactant and an alkali salt;
and forming the resulting composition into a bar.
The present invention further relates to a laundry bar made by the
subject process.
The present invention further relates to a granular laundry detergent
made by the subject process.
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The present invention further relates to a premix composition consisting
essentially of an amine oxide component and an acid, for use in the subject
process. This premix is formed by mixing an amine oxide component with an
acid. In a preferred embodiment, the premix composition is in the form of a
paste. Herein, "paste" means a soft viscous mass of liquid. The amine oxide
component / acid premix preferably contains water, amine oxide component
and acid. Preferably, the premix contains from about 1 % to about 80% water,
more preferably from about 5% to about 50%, more preferably still from about
20% to about 40%. Preferably, the total combined percent of amine oxide
component and acid in the premix is from about 20% to about 80%, more
preferably from about 30% to about 70%, more preferably still about 65%. The
ratio of amine oxide component to acid is from about 25:1 to about 1:4, more
preferably from about 3:1 to about 1:1. In one embodiment, the ratio of amine
oxide component is preferably greater than the ratio of acid.
A. Amine Oxide Component
The amine oxide component may be either an amine oxide, a high
active amine oxide complex, or mixtures thereof.
Amine oxide surfactants for use in the present process preferably have
the formula R1 R2R3N0, wherein R1 is a substituted or unsubstituted alkyl or
alkenyl preferably containing from about 8 to about 30 carbon atoms; more
preferably from about 8 to about 18; more preferably from about 12 to about
18.
R2 and R3 are independently substituted or unsubstituted alkyl or
alkenyl groups preferably containing from about 1 to about 18 carbon atoms,
more preferably from about 1 to about 4. More preferably, R2 and R3 are
independently methyl groups; examples of such amine oxides include,
dodecyldimethyl amine oxide, tetradecyldimethyl amine oxide,
hexadecyldimethyl amine oxide, octadecyldimethyl amine oxide, and
coconutalkyldimethyl amine oxides.
Examples of suitable amine oxides for use in the present process
include dodecyldimethyl amine oxide, tridecyldimethyl amine oxide,
tetradecyidimethyl amine oxide, pentadecyldimethyl amine oxide,
hexadecyldimethyl amine oxide, heptadecyldimethyl amine oxide,
octadecyldimethyl amine oxide, dodecyldiethyl amine oxide, tetradecyldimethyl
amine oxide, hexadecyldiethyl amine oxide, octadecyldiethyl amine oxide,
dodecyldipropyl amine oxide, tetradecyldipropyl amine oxide,
hexadecyldipropyl amine oxide, octadecyldipropyl amine oxide, dodecyldibutyl
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amine oxide, tetradecyldibutyl amine oxide, hexadecyldibutyl amine oxide,
octadecyldibutyl amine oxide, dodecylmethylethyl amine oxide,
tetradecylethylpropyl amine oxide, hexadecylpropylbutyl amine oxide, and
octadecylmethylbutyl amine oxide. Preferred amine oxides include, C12-C18
5 alkyl dimethyl amine oxides, more preferably C14-C16-
Another preferred amine oxide is ADMOXT"", which is a C14 amine
oxide dehydrate. ADMOXTM and other amine oxides useful in the present
process are set forth in U.S. Patent No. 5,292,955 (Smith and Sauer, issued
March 8, 1994).
Also useful are amine oxide surfactants made by the oxidation of tertiary
amines prepared from mixed alcohols obtainable from coconut oil. Such
coconutalkyl amine oxides are preferred from an economic standpoint
inasmuch as it is not necessary for the present purposes to separate the mixed
alcohol fractions into their pure components to secure the pure chain length
fractions of the amine oxides.
In a preferred embodiment, the amine oxide is a liquid amine oxide
formulation. The percentage of amine oxide in the liquid amine oxide
formulation as well as the type of amine oxide are not critical to the
successful
operation of the instant process, or the resulting laundry detergent
composition.
Accordingly, any known or conventional liquid amine oxide formulation can be
used. Preferably, liquid amine oxide formulations useful in the present
invention have up to 50% amine oxide, more preferably from about 1 % to
about 50%, more preferably still from about 20% to about 40%. It is
understood, however, that formulations containing higher or lower
concentrations of amine oxide can also be used in the present process.
However, more concentrated formulations are preferred from a manufacturing
cost standpoint. The remainder of the liquid amine oxide formulation will
typically, and preferably, be water. Less preferred liquid formulations are
single
phase mixtures of water and water-miscible solvents.
Liquid amine oxide formulations for use in the present process can be
prepared by known and conventional methods. Such methods normally
involve the controlled oxidation of tertiary amines to the corresponding amine
oxide using a strong oxidizing agent. A preferred oxidizing agent is hydrogen
peroxide. A dilute, or preferably concentrated (30% by weight of more),
hydrogen peroxide solution is added in a stochiometric or greater amount to a
liquid solution containing the tertiary amine for conversion thereof to the
amine
oxide. Reaction rates and amine oxide yields can be improved by
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incorporation of catalysts and or cheiating agents well known in the
surfactant
art for this particular application. Methods for making amine oxide
surfactants
are described, for example, in U.S. Patent 3,215,741 (Chadwick, issued
November 2, 1965), U.S. Patent 3,223,647 (Drew and Voss, issued December
14, 1965), British Patent 437,566 (issued October 31, 1935), and U.S. Patent
4,565,891 (Correa and Riley, issued July 19, 1984).
In an alternative embodiment, in combination with or in place of the
above discussed amine oxides (i.e., non-complexed amine oxides), high active
amine oxide complexes are used in the present process. Generally speaking,
such high active amine oxide complexes include solid amine oxide surfactant
compositions comprising an amine oxide and a complexing acid selected from
the group consisting of saturated carboxylic acid with at least 5 carbon
atoms,
unsaturated carboxylic acid with at least 5 carbon atoms, phosphoric acid, and
mixtures thereof. More specifically, the amine oxide of such a complex
preferably has the formula R11 R12R13N0, where R11 is a substituted or
unsubstituted alkyl or alkenyl group containing from about 6 to about 30
carbon
atoms and Groups R12 and R13 are each substituted or unsubstituted alkyl or
alkenyl groups containing from about 1 to about 18 carbon atoms. The
complexing acid of such a complex preferably is selected from the group
consisting of citric acid, polyacrylic acid, malonic acid, adipic acid, oxalic
acid,
glutaric acid, pthalic acid, lauric acid, oleic acid, benzoic acid, and
butyric acid,
tetra sodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP),
diethylene triamine penta methyl phosphoric acid, hydroxyethane
diphosphonic acid, ethylenediamine tetra methyiene phosphoric acid, and
mixtures thereof. Such complexes may be prepared by admixing the
complexing acid with an amine oxide surfactant formulation by admixing 1 mole
of complexing acid with X moles) of amine oxide, where X is from about 1 to
about equal to the number of acid groups of the complexing acid. The pH of
the admixture is from about 1 to about 3, whereby a visible precipitate in the
admixture is formed. The formed precipitate is separated from the admixture,
preferably by mechanical means, and allowed to dry. The separated
precipitate forms the solid compositions of the present invention, which solid
compositions consist of the amine oxide and complexing acid described above.
Other high active amine oxide complexes useful in the present invention
include those disclosed in U.S. Patent 5,399,296 ~erenga et al., issued
March 21, 1995).
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The amount of amine oxide component used in the laundry composition
making process of the present invention (by weight of the resulting laundry
detergent composition) is preferably from about 1 % to about 50%, more
preferably from about 0.5% to about 30%, more preferably still from about
0.9% to about 25%. More preferably, particularly with respect to making
laundry detergent bar compositions, the amount of amine oxide component is
preferably from about 1 % to about 30%, more preferably from about 0.5% to
about 10%, more preferably still from about 0.9% to about 4%.
B. Acid
One or more acids are used in the present process to form the acid
amine oxide premix. Such acids useful in the present process preferably
include carboxylic acids, phosphoric acids, sulfuric acids, acid precursors of
anionic surfactants, or mixtures thereof; more preferably citric acid, acetic
acid,
phosphoric acid, acid pyrophosphate, sulfuric acid, the acidic form .of linear
alkyl benzene sulfonate (HLAS), the acidic form of alkyl sulfate (HAS), or
mixtures thereof; more preferably still, sulfuric acid and HLAS.
Preferably the HLAS is an acidic form of C11-C1 g alkyl benzene
sulfonates.
Preferably the HAS is an acidic form of primary, branched-chain and
random C1 p-C20 alkyl sulfates.
The amount of acid precursor of an anionic surfactant used in the
present process (by weight of the resulting laundry detergent composition) is
preferably from about 1 % to about 30%, more preferably from about 2.5% to
about 20%. More preferably, particularly with respect to making a laundry
detergent bar compositions, the amount of acid precursor of an anionic
surfactant is preferably from about 1 % to about 10%, more preferably from
about 2.5% to about 6%.
C. Anionic Surfactants
Anionic surfactants useful in the present process include synthetic
anionic surfactants and soap.
1. Synthetic Anionic Surfactants
Synthetic anionic surfactants which are suitable for use herein include
the water-soluble salts, preferably the alkali metal, ammonium and
alkylolammonium salts of organic sulfuric reaction products having in their
molecular structure an alkyl group containing from about 10 to about 20 carbon
atoms and a sulfonic acid or sulfuric acid ester group. (Included herein in
the
term "alkyl" is the alkyl portion of acyl groups.) Examples of this group of
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synthetic surfactants are the sodium and potassium alkyl sulfates, especially
those obtained by sulfating the higher alcohols (Cg_1 g carbon atoms) such as
those produced by reducing the glycerides of tallow or coconut oil; and the
sodium and potassium alkyl benzene sulfonates in which the alkyl group
contains from about 9 to about 15 carbon atoms, in straight chain or branched
chain configuration, e.g., those of the type described in U.S. Patents
2,220,099
and 2,477,383. Especially valuable are linear straight chain alkyl benzene
sulfonates in which the average number of carbon atoms in the alkyl group is
from about 11 to 13, abbreviated as C11-13 ~S~ The alkali metal salts,
particularly the sodium salts of these surfactants are preferred. Alkyl
benzene
sulfonates and processes for making them are disclosed in U.S. Patent Nos.
2,220,099 and 2,477,383.
Preferred synthetic anionic surfactants are C10-18 linear alkyl benzene
sulfonates, C10-14 alkyl glyceryl ether sulfonates, and C10-18 alkyl sulfates.
The amount of synthetic anionic surfactant used in the present process
(by weight of the resulting laundry detergent composition) is preferably from
about 5% to about 60%, more preferably from about 15% to about 30%.
2. Soaps
Herein, "soap" means salts of fatty acids. The fatty acids are linear or
branched containing from about 8 to about 24 carbon atoms, preferably from
about 10 to about 20 carbon atoms. The average carbon chain length for the
fatty acid soaps is from about 12 to about 18 carbon atoms, preferably from
about 14 to about 16 carbon atoms. Preferred salts of the fatty acids are
alkali
metal salts, such as sodium and potassium, especially sodium. Also preferred
salts are ammonium and alkylolammonium salts.
The fatty acids of soaps useful in the present process are preferably
obtained from natural sources such as plant or animal esters; examples include
coconut oil, palm oil, palm kernel oil, olive oil, peanut oil, corn oil,
sesame oil,
rice bran oil, cottonseed oil, babassu oil, soybean oil, castor oil, tallow,
whale
oil, fish oil, grease, lard, and mixtures thereof. Preferred fatty acids are
obtained from coconut oil, tallow, palm oil (palm stearin oil), palm kernel
oil,
and mixtures thereof. Fatty acids can be synthetically prepared, for example,
by the oxidation of petroleum, or by hydrogenation of carbon monoxide by the
Fischer-Tropsch process.
Alkali metal soaps can be made by direct saponification of the tats and
oils or by the neutralization of the free fatty acids which are prepared in a
separate manufacturing process. Particularly useful are the sodium and
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potassium salts of the mixtures of fatty acids derived from coconut oil and
tallow, i.e., sodium and potassium tallow and coconut soaps.
Preferred soap raw materials for present process are soaps made from
mixtures of fatty acids from tallow and coconut oil. Typical mixtures have
tallow:coconut fatty acid ratios of 85:15, 80:20, 75:25, 70:30, and 50:50;
preferred ratios are about 80:20 to 65:35.
Preferred soap raw materials for the present process are neat soaps
made by kettle (batch) or continuous saponification. Neat soaps typically
comprise from about 65% to about 75%, preferably from about 67% to about
72%, alkali metal soap; from about 24% to about 34%, preferably from about
27% to about 32%, water; and minor amounts, preferably less than about 1
total, of residual materials and impurities, such as alkali metal chlorides,
alkali
metal hydroxides, alkali metal carbonates, glycerin, and free fatty acids.
Another preferred soap raw material is soap noodles or flakes, which are
typically neat soap which has been dried to a water content of from about 10%
to about 20%. The other components above are proportionally concentrated.
Soaps are optionally used in the present process at levels of no more
than about 70%, by weight of the resulting laundry detergent composition. The
amount of soap used in the present process (by weight of the resulting laundry
detergent composition) is preferably from about 5% to about 70%, more
preferably from about 10% to about 50%.
in a preferred embodiment, the final composition contains from about
35% to about 50% soap (more preferably from about 35% to about 40%), from
about 5% to about 10% surfactant (more preferably from about 7% to about
10%), and from about 1 % to about 4% amine oxide.surfactant (more preferably
from about 1.5% to about 3%). Preferably, the surfactant is LAS. Preferably
the acid used to make such an embodiment is HLAS. Such an embodiment is
believed to provide improved cleaning and sudsing in hard water, good calcium
tolerance, and improved prevention of loss of fabric whitening (i.e., prevents
fabric from becoming dingy).
In another preferred embodiment, the final composition contains from
about 20% to about 80% soap (more preferably from about 30% to about
50%), from about 1 % to about 5% of alkyl sulfate (more preferably from about
2% to about 3%), and from about 0.5% to about 5% amine oxide (more
preferably from about 1 % to about 4%). Preferably, the soap is a mixture of
fatty acids (preferably from about 10 to about 18 carbon atoms) from tallow
and
coconut oil. Preferably, the alkyl sulfate has chain lengths of from about 10
to
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about 18 carbon atoms, more preferably from about 12 to about 14. It is
believed such an embodiment provides improved greasy soil removal.
D. Alkali Salts
The alkali salt used in the present process (in addition to its possible use
5 as a builder and providing alkalinity to the overall composition for
improved
detergency) serves as a neutralizing agent for the acid precursor of an
anionic
surfactant which is employed in the present process.
Alkali salts useful in the present process include alkali metal carbonates,
bicarbonates, and phosphates. Preferred alkali salts include sodium carbonate
10 (soda ash), sodium bicarbonate; more preferably sodium carbonate.
The amount of alkali salt used in the present process (by weight of the
resulting laundry detergent composition) is preferably from about 2% to about
40%, more preferably from about 10% to about 20%.
E. Builders
The laundry detergent compositions produced by the present process
preferably contain from about 0.5% to about 30%, more preferably from about
5% to about 15% detergent builder. These detergent builders can be, for
example, water-soluble alkali-metal salts of phosphate, pyrophosphates,
orthophosphates, tripolyphosphates, higher polyphosphates, and mixtures
thereof. Preferred builders are a water-soluble alkali-metal salt of
tripolyphosphate, and a mixture of tripolyphosphate and pyrophosphate. The
builder can also be a non-phosphate detergent builder. Specific examples of
non-phosphate, inorganic detergency builders include water-soluble inorganic
carbonate and bicarbonate salts. The alkali metal {e.g., sodium and
potassium) carbonates, bicarbonates, and silicates are particularly useful
herein. Specific preferred examples of builders include sodium
tripofyphosphates (STPP) and tetra sodium pyrophosphates (TSPP), and
mixtures thereof. Other specifically preferred examples of builders include
zeolites and polycarboxylates, and co-polymers of acrylic acid and malefic
acid.
Granular formulations typically comprise from about 10% to about 80%,
more typically from about 15% to about 50% by weight, of the detergent
builder.
F. Moisture
The laundry detergent bars made by the present process preferably
comprise from about 0.5% to about 30% of moisture, more preferably from
about 1 % to about 5%.
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G. Additional Ingredients
The detergent compositions produced by the present process may
further include other ingredients commonly used in detergent products. A
typical listing of the classes and species of optional surfactants, (e.g.
nonionic,
zwitterionic and amphoteric surfactants) optional alkaline builders such as
sodium carbonate trisodium phosphate sodium silicate, etc. and other
ingredients useful herein appears in U.S. Pat. No. 3,664,961, issued to Norris
on May 23, 1972, and EP 550,652, published on April 16, 1992. Such optional
surfactants, if present, can be included at levels up to a total of about 10%,
preferably about 0.5-3%.
A preferred additional component in the laundry detergent composition
is a bleach component. The bleaching component can be a source of -OOH
group, such as sodium perborate monohydrate, sodium perborate tetrahydrate
and sodium percarbonate. Sodium percarbonate (2Na2C03~3H202) is
preferred since it has a dual function of both a source of HOOH and a source
of sodium carbonate. Another optional bleaching component is a peracid per
se, such as a formula:
CH3(CH2)w-NH-C(O)-(CH2)zC03H
wherein z is from 2 to 4 and w is from 4 to 10. The bleaching component can
contain, as a bleaching component stabilizer, a chelating agent of
polyaminocarboxylic acids, polyaminocarboxylates such as
ethylenediaminotetraacetic acid, diethylenetriaminopentaacetic acid (DTPA),
and ethylenediaminodisuccinic acid, and their salts with water-soluble alkali
metals. The bleach components, if any, can be added to the laundry detergent
composition, if any, at a level up to 20%, preferably from about 1 % to about
10%, more preferably from about 2% to about 6%.
Mixtures of bleaching agents can also be used.
Peroxygen bleaching agents, the perborates, the percarbonates, etc.,
are preferably combined with bleach activators, which lead to the in situ
production in aqueous solution (i.e., during the washing process) of the
peroxy
acid corresponding to the bleach activator. Various nonlimiting examples of
activators are disclosed in U.S. Patent 4,915,854, issued April 10, 1990 to
Mao
et al, and U.S. Patent 4,412,934. The nonanoyloxybenzene suifonate (NOBS)
and tetraacetyl ethylene diamine (TAED) activators are typical, and mixtures
thereof can also be used. See also U.S. 4,634,551 for other typical bleaches
and activators useful herein.
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A preferred additional ingredient is a fabric softening clay, preferably a
smectite-type clay and a clay flocculating agent, having a high molecular
weight greater than about 100,000.
Soil suspending agents may be additionally used. In the present
invention, their use is balanced with the fabric softening clay/clay
flocculating
agent combination to provide optimum cleaning and fabric softening
performance. One such soil suspending agent is an acrylic/maleic copolymer,
commercially available as SOKALAN~, from BASF Corp. Other soil
suspending agents include polyethylene glycols having a molecular weight of
about 400 to 10,000, and ethoxylated mono- and poiyamines, and quaternary
salts thereof.
A particularly preferred additional component of the present invention is
a detergent chelant. Such chelants are able to sequester and chelate alkali
cations (such as sodium, lithium and potassium), alkali metal earth cations
(such as magnesium and calcium), and most importantly, heavy metal cations
such as iron, manganese, zinc and aluminum. Preferred cations include
sodium, magnesium, zinc, and mixtures thereof. The detergent chelant is
particularly beneficial for maintaining good cleaning performance and improved
surfactant mileage, despite the presence of the softening clay and the clay
flocculating agent.
The detergent chelant is preferably a phosphonate chelant, particularly
one selected from the group consisting of diethylenetriamine penta(methylene
phosphoric acid), ethylene diamine tetra(methylene phosphoric acid), and
mixtures and salts and complexes thereof, and an acetate chelant, particularly
one selected from the group consisting of diethylenetriamine penta(acetic
acid), ethylene diamine tetra(acetic acid), and mixtures and salts and
complexes thereof. Particularly preferred are sodium, zinc, magnesium, and
aluminum salts and complexes of diethylenetriamine penta(methylene
phosphonate) diethylenetriamine penta (acetate), and mixtures thereof.
Preferably such salts or complexes have a molar ratio of metal ion to
chelant molecule of at least 1:1, preferably at least 2:1.
The detergent chelant may be included in the laundry detergent
composition at a level up to about 5%, preferably from about 0.1 % to about
3%, more preferably from about 0.2% to about 2%, most preferably from about
0.5% to about 1.0%.
Another preferred additional component of the laundry detergent
composition is fatty alcohol having an alkyl chain of 8 to 22 carbon atoms,
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more preferably from 12 to 18 carbon atoms. A preferred fatty alcohol has an
alkyl chain predominantly containing from 16 to 18 carbon atoms, so-called
"high-cut fatty alcohol," which can exhibit less base odor of fatty alcohol
relative
to broad cut fatty alcohols. Typically fatty alcohol, if any, is present in
the
laundry detergent composition at up to a level of 10%, more preferably from
about 0.75% to about 6%, most preferably from about 2% to about 5%. The
fatty alcohol is generally added to a laundry detergent composition as free
fatty
alcohol. However, low levels of fatty alcohol can be introduced into the
laundry
detergent compositions as impurities or as unreacted starting material. For
example, laundry bars based on coconut fatty alkyl sulfate can contain, as
unreacted starting material, from 0.1 % to 3.5%, more typically from 2% to 3%,
by weight of free coconut fatty alcohol on a coconut fatty alkyl sulfate
basis.
Another preferred additional component in the laundry bar or granular
detergent is a dye transfer inhibiting {DTI) ingredient to prevent diminishing
of
color fidelity and intensity in fabrics. A preferred DTI ingredient can
include
polymeric DTI materials capable of binding fugitive dyes to prevent them from
depositing on the fabrics, and decolorization DTI materials capable of
decolorizing the fugitives dye by oxidation. An example of a decolorization
DTI
is hydrogen peroxide or a source of hydrogen peroxide, such as percarbonate
or perborate. Non-limiting examples of polymeric DTI materials include
polyvinylpyrridine N-oxide, polyvinyipyrrolidone (PVP), PVP-polyvinylimidazole
copolymer, and mixtures thereof. Copolymers of N-vinylpyrrolidone and N
vinylimidazole polymers (referred to as "PVPI") are also preferred for use
herein. The amount of DTI included in the subject compositions, if any, is
about
0.05-5%, preferably about 0.2-2%.
Another preferred additional component in the laundry detergent
composition is a secondary fabric softener component in addition to the
softening clay. Such materials can be used, if any, at levels of about 0.1 %
to
5%, more preferably from 0.3% to 3%, and can include: amines of the formula
R4R5RgN, wherein R4 is C5 to C22 hydrocarbyl, R5 and Rg are independently
C1 to C10 hydrocarbyl. One preferred amine is ditallowmethyl amine;
complexes of such amines with fatty acid of the formula R7COOH, wherein R7
is Cg to C22 hydrocarbyl, as disclosed in EP No. 0,133,804; complexes of such
amines with phosphate esters of the formula R80-P(O)(OH)-ORg and HO-
P(O)(OH)-ORg, wherein R8 and Rg are independently C1 to C20 alkyl of alkyl
ethoxylate of the formula -alkyl-(OCH2CH2); cyclic amines such as
imidazolines of the genera! formula 1-(higher alkyl) amido (lower alkyl)-2-
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(higher alkyl)imidazoline, where higher alkyl is from 12 to 22 carbons and
lower
alkyl is from 1 to 4 carbons, such as described in UK Patent Application GB
2,173,827; and quaternary ammonium compounds of the formula
R10R11 R12R13N+X-~ wherein R10 is alkyl having 8 to 20 carbons, R11 is
alkyl having 1 to 10 carbons, R12 and R13 are alkyl having 1 to 4 carbons,
preferably methyl, and X is an anion, preferably CI- or Br, such as C12-13
alkyl
trimethyl ammonium chloride.
Sodium sulfate is a well-known filler that is compatible with the
compositions of this invention. It can be a by-product of the surfactant
sulfation
and sulfonation processes, or it can be added separately. Other filter
materials
include bentonite and talc.
Calcium carbonate (also known as Calcite) is also a well known and
often used filler component of laundry detergent compositions. Fillers include
minerals, such as talc and hydrated magnesium siiicate-containing minerals,
where the silicate is mixed with other minerals, e.g., old mother rocks such
as
dolomite. Filler materials are typically used, if included, at levels up to
40%,
preferably from about 5% to about 25%.
Binding agents for holding the laundry detergent composition together in
a cohesive, soluble form can also be used, and include natural and synthetic
starches, gums, thickeners, and mixtures thereof. Such materials, if included,
are typically at levels up to about 3%, preferably about 0.5-2%. Glycerine is
commonly incorporated in laundry bar compositions. If included, it is
typically
at concentrations up to about 3%, preferably about 0.5-1.5%. Optical
brighteners are also preferred optional ingredients in laundry detergent
compositions of the present invention. Preferred optical brighteners are
diamino stilbene, distyrilbiphenyl-type optical brighteners. Preferred as
examples of such brighteners are 4,4'-bisf[4-anilino-6-bis(2-hydroxyethyl)
amino-1,3,5-trizin-2-yl]amino}stilbene-2,2'-disulfonic acid disodium salt, 4-
4'-
bis(2-sulfostyryl) biphenyl and 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-
2-yl)
amino]stilbene-2,2'-disulfonic acid disodium salt. Such optical brighteners,
or
mixtures thereof, can be used at levels in the laundry detergent composition
of
from about 0.05% - 1.0%.
Dyes, pigments, germicides, and perfumes may also be added to the
laundry detergent composition. If included, they are typically at levels up to
about 0.5%.
Another additional component useful in the present process is a
photobleach material, particularly phthalocyanine photobleaches which are
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described in U.S. Patent 4,033,718 issued July 5, 1977. Preferred
photobleaches are metal phthalocyanine compounds, the metal preferably
having a valance of +2 or +3; zinc and aluminum are preferred metals. Such
photobleaches are available, for example, under the tradename TINOLUS or
5 as zinc phthalocyanine sulfonate. The photobleach components, if included,
are typically in the subject compositions at levels up to about 0.02%,
preferably
from about 0.001 % to about 0.015%, more preferably from about 0.002% to
about 0.01 %.
Enzymes can also be included in the laundry detergent composition for
10 a variety of purposes, including removal of protein-based, carbohydrate-
based,
or triglyceride-based stains from substrates, for the prevention of refugee
dye
transfer in fabric laundering, and for fabric restoration. Suitable enzymes
include proteases, amylases, lipases, cellulases, peroxidases, and mixtures
thereof of any suitable origin, such as vegetable, animal, bacterial, fungal
and
15 yeast origin. Preferred selections are influenced by factors such as pH-
activity
and/or stability optima, thermostability, and stability to active detergents,
builders and the like. In this respect bacterial or fungal enzymes are
preferred,
such as bacterial amylases and proteases, and fungal cellulases.
Suitable examples of proteases are the subtilisins which are obtained
from particular strains of B. subtilis and 8. licheniformis. Suitable
proteases
include ESPERASE~ by Novo industries A/S of Denmark, hereinafter "Novo";
ALCALASE~ and SAVINASE~ from Novo and MAXATASE~ from
International Bio-Synthetics, Inc., The Netherlands; as well as Protease A as
disclosed in EP 130,756 A, January 9, 1985 and Protease B as disclosed in EP
303,761 A, April 28, 1987 and EP 130,756 A, January 9, 1985. See also a
high pH protease from Bacillus sp. NCIMB 40338 described in WO 9318140 A
to Novo. Amylases suitable herein, include, for example, -amylases
described in GB 1,296,839 to Novo; RAPIDASE~, International Bio-Synthetics,
Inc. and TERMAMYL~, Novo.
Celluiases usable herein include both bacterial and fungal types.
Suitable celiulases are also disclosed in GB-A-2.075.028; GB-A-2.095.275 and
DE-OS-2.247.832. CAREZYME~ and CELLUZYME~ (Novo) are especially
useful. See also WO 9117243 to Novo.
Enzymes are normally incorporated into detergent or detergent additive
compositions at levels sufficient to provide a "cleaning-effective amount".
The
term "cleaning effective amount" refers to any amount capable of producing a
cleaning, stain removal, soil removal, whitening, deodorizing, or freshness
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improving effect on substrates such as fabrics, dishware and the like. In
practical terms for current commercial preparations, typical amounts are up to
about 5 mg by weight, more typically 0.01 mg to 3 mg, of active enzyme per
gram of the detergent composition. Stated otherwise, the compositions herein
will typically comprise from 0.001 % to 5%, preferably 0.01 %-1 % by weight of
a
commercial enzyme preparation. Protease enzymes are usually present in
such commercial preparations at levels sufficient to provide from 0.005 to 0.1
Anson units (AU) of activity per gram of composition. For certain detergents,
such as in automatic dishwashing, it may be desirable to increase the active
enzyme content of the commercial preparation in order to minimize the total
amount of non-catalytically active materials and thereby improve
spotting/filming or other end-results. Higher active levels may also be
desirable
in highly concentrated detergent formulations.
H. Processing
1. Bars
In laundry bar making embodiment of the present invention, the process
includes mixing an amine oxide component and an acid to form a premix;
mixing the premix, an anionic surfactant and an alkali salt; and forming the
resulting composition into a bar.
The process of the present invention can employ conventional soap or
detergent bar making equipment with some or all of the following key
equipment: blender/mixer (e.g., ribbon blender), mill, refining plodder (e.g.,
duplex plodder), two-stage vacuum plodder, fogo printer/cutter, cooling tunnel
and wrapper.
In a typical process, the amine oxide component and acid are mixed in a
blender, a planetary mixer, kneader and/or extruder, to form a premix. This
premix is mechanically worked to effect homogeneity and to complete the
neutralization of the premix.
Subsequently, the premix is combined with other raw materials
(including anionic surfactant and alkali salt) in a blender. This mixture of
premix and other raw materials is referred to as the seat. Additional soap and
other optional surfactants are then added, followed by the builder and any
additional adjunct ingredients. If desired, polyphosphate can be used as an
alkaline salt in the neutralization. The high shear mixing can take from one
minute to one hour, with the usual mixing time being from about two to twenty
minutes. Preferably, the temperature is from about 74°C to about
80°C.
Examples of equipment which may be used for the high shear mixing include,
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the Sigma Mixer high sheer mixer, manufactured by Fabdecon Engineers,
Bombay India; or a plough sheer mixer, manufactured by Littleford Day, Inc.,
Kentucky, U.S.A.
The blender mix is charged to a surge tank. The product is conveyed
from the surge tank to the mill. As the mixture is being milled, the mixture
is
cooled to a temperature of from about 40°C to about 62°C.
Preferably, the
mixture is cooled by the running of cool water through the mill, which in turn
cools the mixture being milled.
After milling or preliminary plodding after milling, the product is then
70 conveyed to a double vacuum plodder, operating at high vacuum, e.g., 400 to
740 mm of mercury vacuum, so that entrapped air is removed. The product is
extruded and cut to the desired bar length, and printed with the product brand
name. The printed bar can be cooled, for example in a cooling tunnel, before
it
is wrapped, cased, and sent to storage.
2. Granules
The amine oxide component / acid premix may be employed in the
making of both low density (below 550 g/I) and high density (at least 550 g/I)
granular laundry detergent compositions. Such high density detergent
compositions typically comprised from about 30% to about 90% of detersive
surfactant.
Low density compositions can be prepared by standard spray-drying
processes. Various means and equipment are available to prepare high
density granular detergent compositions. Current commercial practice in the
field employs spray-drying towers to manufacture granular laundry detergents
which often have a density less than about 500 g/I. Accordingly, if spray
drying
is used as part of the overall process, the resulting spray-dried detergent
particles must be further densified using the means and equipment described
hereinafter. In the alternative, the formulator can eliminate spray-drying by
using mixing, densifying and granulating equipment that is commercially
available. The following is a nonlimiting description of such equipment
suitable
for use herein.
High speed mixer/densifiers can be used in the present process. for
example, the device marketed under the trademark "Lodige CB30 Recycler"
comprises a static cylindrical mixing drum having a central rotating shaft
with
mixing/cutting blades mounted thereon. Other such apparatus includes the
devices marketed under the trademark "Shugi Granulator" and under the
trademark "Drais K-TTP 80". Equipment such as that marketed under the
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trademark "Lodige KM600 Mixer", "Fukae High Speed Mixer" and "Food
Processor" can be used for further densification.
In one mode of operation, the compositions are prepared and densified
by passage through two mixer and densifier machines operating in sequence.
Thus the desired compositional ingredients can be admixed and passed
through a Lodige mixer using residence times of about 0.1 to about 1 minute,
then passed through a second Lodige mixer using residence times of about 1
minute to about 5 minutes.
In another mode, an aqueous slurry comprising the desired formulation
ingredients is sprayed into a fluidized bed of particulate surfactants. the
resulting particles can be further densified by passage through a Lodige
apparatus, as noted above.
The final density of the resulting particles can be measured by a variety
of simple techniques, which typically involve dispensing a quantity of the
granular detergent into a container of known volume, measuring the weight of
detergent and reporting the density in g/I.
The amine oxide component / acid premix is prepared as described
above, and then introduced to the low density and high density granular
composition making processes where surfactant is normally introduced. In
spray-drying processes, it is preferable to add additional water to the
premix,
either during its formation or after. The resulting slurry will facilitate
spray-
drying of the surfactant. In processes which do not involve spray-drying, the
paste form of the premix is preferred.
The following examples further describe and demonstrate the preferred
embodiments within the scope of the present invention. The examples are
given solely for the purpose of illustration, and are not to be construed as
limitations of the present invention since many variations thereof are
possible
without departing from its spirit and scope.
Example 1
This example shows a premix of amine oxide and acid for subsequent
use in the solid laundry composition making process of the present invention:
Component % by Weight
HLAS 60
Tetradecyldimethyl (C14) amine oxide 40
The HLAS and amine oxide are mixed together until a constant
viscosity is reached (approximately 30 seconds to 2 minutes of continuous
mixing).
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Examale 2
This example shows a premix of amine oxide and acid for subsequent
use in the solid laundry composition making process of the present invention:
Component % by Weight
H LAS 41
Tetradecyldimethyl (C14) amine oxide 59
The HLAS and amine oxide are mixed together until a constant
viscosity is reached {approximately 30 seconds to 10 minutes of continuous
mixing).
Example 3
This example shows a process of the present invention for making a
synthetic laundry detergent bar having the following final composition:
Component % by Weight
NaCFAS 17.85
ADMOX SC-1485 (amine oxide) 4.65
Sodium Carbonate 15.00
Sodium Sulfate 8.55
Sodium Tripolyphosphate (STPP) 11.60
Calcium Carbonate 30.00
Coco Fatty Alcohol 1.00
Glycerine 1.00
Titanium Dioxide 1.00
Diethylenetriamine pentacarboxylic acid 0.70
Zeolite 1.00
Substituted Methyl Cellulose 0.50
Fluorescent Whitening Agents 0.20
Perfume 0.50
Moisture 4.84
Other conventional ingredients. balance to 100
Combine ADMOX and sulfuric acid, mixing for 2 min. to form a premix.
Subsequently combine soda ash, sodium coconut fatty alcohol sulfate, STPP,
and zeolite with the premix; and mix for 3 minutes {this mixture is referred
to as
the "seat"). Add diethylenetriamine pentacarboxylic acid and coco fatty
alcohol. Continue mixing for 30 seconds. Add titanium dioxide and calcium
carbonate. Then add brighteners, substituted methyl cellulose, glycerine and
other conventional/minor ingredients. Subsequently add perfume when
desired batch consistency is met. Drop the batch and form into bars.
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Example 4
This example shows a process of the present invention for making a
synthetic and soap laundry detergent bar having the following final
composition:
5 Component % by Weight
NaLAS 2.50
Soap 47.50
Soda Ash 8.50
Water 1.95
10 Fluorescent Whitening Agent 0.02
Bluing Agent 0.10
Substituted Methyl Cellulose 0.50
ADMOX SC-1485 1.80
Sodium Sulfate 5.00
15 Talc 4.22
Perfume 0.260
Other conventional ingredients balance to 100
Combine ADMOX and HLAS, mixing for 2 min., to form a premix.
Subsequently combine soda ash, and 50% of talc with the premix; and mix for
20 30 seconds (this mixture is referred to as the "seat"). Add water over a 30
second period, and mix for 2 minutes. Add fluorescent whitening agent and
substituted methyl cellulose, and mix for 30 seconds. Add soap and mix for 3
minutes (addition time inclusive). Add sodium sulfate and balance of talc, and
mix for 1 minute. Add perfume, and mix for 30 seconds. Drop the batch and
form into bars.
Example 5
This example shows a process of the present invention for making
laundry detergent granules having the following final composition:
Component % by Weight
NaLAS 18
Fluorescent Whitening Agent 0.2
Bluing Agent 0.0045
Substituted Methyl Cellulose 0.4
ADMOX SC-1485 0.6
Zeolite 22.5
Chelant 0.9
Perborate 3
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NOBS 2.5
Soil Dispersing Agent 0.25
Savinase 0_7
Termamyl 0.36
Carezyme 0.35
PVPI 0.1
PVP 0.3
Other conventional ingredients balance to 100
Combine the ADMOX and the NaLAS, mixing for 2 min., to form a
premix. Subsequently combine the soda ash, and 50% of the talc with the
premix; and mix for 30 seconds. Add additional water until a slurry is formed.
The slurry is subsequently spray-dried in a tower to form low density granules
of 500 g/I.
Example 6
This example shows a process of the present invention for making
laundry detergent granules having the following final composition:
Component % by Weight
HLAS 15.9
Cocounutalkyl amine oxides 22.5
Sodium carbonate 38.0
Precipitated Silica Sipernat D22S 17.7
Other conventional ingredients balance to 100
Combine the coconutalkyl amine oxides and the HLAS, mixing for 10
minutes, to form a premix. Combine the soda ash and Sipernat with the
premix, and mix for 15 seconds using a Tilt-a-pin mixer (supplied by
Processall(. The blender mix is charged to Tilt-a-plow mixer (supplied by
Processall) and mixed for 2 minutes. The mixture is subsequently charged to a
fluid bed dryer supplied by NIRO Inc. for 15 minutes at 120°C.
Example 7
This example shows a process of the present invention for making
laundry detergent granules having the following final composition:
Component % by Weight
HLAS 11.8
Coconutalkyl amine oxides 16.7
Sodium Carbonate 36.9
Precipitated Silica Sipernat D22S 15.0
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Zeolite Type A 13.8
Other conventional ingredients balance to 100
Combine the coconutalkyl amine oxides and the HLAS, mixing for 10
minutes, to form a premix. Combine the sodium carbonate and Sipernat with
the premix. Mix for 30 seconds using a Food Processor (TK-55, supplied by
Tesukomu, Japan). Subsequently charge the mixture to a Fluid Bed Dryer
{supplied by NIRO Inc.) for 15 minutes at 120°C.
Example 8
This example shows a process of the present invention for making
laundry detergent granules having the following final composition:
Component % by Weight
HLAS 11.8
Coconutalkyl amine oxides 16.7
Sodium Sulfate 36.9
Precipitated Silica Sipernat D22S 15.0
Zeolite Type A 13.8
Other conventional ingredients balance to 100
Combine the coconutalkyl amine oxides and the HLAS, mixing for 10
minutes, to form a premix. Combine the sodium sulfate and Sipernat with the
premix. Mix for 30 seconds using a Food Processor (TK-55, supplied by
Tesukomu, Japan). Subsequently charge the mixture to a Fluid Bed Dryer
(supplied by NIRO Inc.) for 15 minutes at 120°C.
Liquid amine oxide is typically very difficult to incorporate into solid
detergent compositions via. conventional laundry bar and granule
manufacturing processes. A major contributor to this difficulty is the huge
amount of moisture such amine oxides bring into the bar formulation. This
moisture results in difficulty in processing and corresponding bar softness,
and/or granule stickiness, issues. However, by premixing liquid amine oxide
with acid, as in the present invention, the resulting premix can be readily
incorporated into solid detergent bar and/or granule compositions,
particularly
laundry detergent bar compositions. Consequently, the aspects and
embodiments of the present invention set forth in this document have many
advantages, including improved physical properties, versus laundry detergent
bars and/or laundry detergent granule compositions comprising an amine oxide
made by an alternate process. Such improved physical properties may
include, improved homogeneity, reduced softness, easier processing, easier
packing and shipping of resulting product, and better economy in use.
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Bar softness is undesirable for a number of reasons. For example, it
causes difFculties in subsequent bar processing steps. Among other things, if
a bar is too soft, it cannot be properly removed from the plodder. In
addition, a
soft bar is subject to deformation during packaging and/or shipping. Although
a
soft bar will likely harden over a period of about 2 weeks, a bar that hardens
quickly coming out of the plodder can be immediately shipped and packed.
Even if one developed an economical means of packing/shipping soft
bars which avoided deformation, a soft bar used by a consumer poses several
undesirable characteristics. For example, the consumer has less control over
application of the detergent to the fabric. A harder bar is less malleable,
again
providing the consumer with more control over detergent delivery.
Laundry bars made with liquid amine oxide employing the present
process have bar hardness/firmness properties comparable to laundry bars
made with solid amine oxide via conventional processing.
The laundry bars produced by the present process have many additional
advantages, including improved sudsing, mildness to the user's hands, and
improved cleaning, yet do not present serious processability problems.
Without intending to be bound by theory, it is believed that an ion-pair is
formed between the acid and the amine oxide when the latter comes in contact
with the former. It is believed the ion pair is brought about by electrostatic
attraction between the acid molecule upon the loss of its hydronium ion and
the
protonated atom of the amine oxide. For example, with respect to a premix of
HLAS and an amine oxide, an ion-pair is believed to be brought about by
electrostatic attraction between the negatively charged sulfonate of HLAS and
the protonated oxygen atom of the amine oxide. The protonation comes from
the hydronium ion of HLAS. More specifically:
R~ R~
R4 ~ SU3Fi + O~-N~ R2 --. R4 ~ SOg;""~HO:-N-~z
Rs Rs
Wherein R1, R2 and R3 are as defined above, and R4 is an alkyl.
it is understood that the examples and embodiments described herein
are for illustrative purposes only and that various modifications or changes
in
light thereof will be suggested to one skilled in the art without departing
from
the scope of the present invention.
