Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
The present invention is related to an improved method
for making aliphatic diperoxyacids having from about 8 to
about 16 carbon atoms.
Peroxygen bleaching agents in general and peroxyaeid
eompounds in particular have long been recognized as
effective bleaching agents for use when the adverse
eolor and fabric damage effects of harsh halogen active
bleaehing agents cannot be to]erated. See, for example,
Canadian Patent 632,620, January 30, 1962, to McCune.
This attraetive nature of peroxyaeid compounds makes it
desirable to be able to make them in the most economieal
manner.
The prior art teaehes the making of peroxyacid
compounds in several ways. Parker et al. in Journal
Ameriean Chemical Society, 79, 1929 (1957), disclose
making diperoxyacids by dissolving a dibasic acid in
sulfurie aeid and adding hydrogen peroxide dropwise.
U.S. Patent 3,079,411, February 26, 1963, to Silbert
et al., discloses forming long chain aliphatie peroxy-
aeids by eombining an aliphatie aeid with an alkane-
sulfonie aeid and then treating the combination with
an exeess of hydrogen peroxide. U.S. Patent 2,813,896,
November 19, 1957, to Krimm, discloses forming perox~acids
by combining sulfuric acid and hydrogen peroxide and
subsequently treating the combination with a carboxylie
aeid. The reaetion is eondueted so that there is at
least one mole of sulfurie acid present at the end of the
reaetion for every six moles of water. All of the above
diselosed methods utilize the batch manufacturing approach.
The use of continuous processes for making
~ . r.. ~
diperoxyacids has also been disclosed. See, for example,
U.S. Patent 3,235,584, February 15, 1966, to Blumbergs
wherein it is disclosed to react an organic acid halide
with an alkali metal or alkaline earth metal peroxide to
form a salt of a peroxycarboxylic acid. Also U.S. Patent
3,284,491, November 8, 1966, to Korach et al. wherein a
peroxyacid is formed in a single liquid phase.
While the prior art teaches several methods for making
peroxyacids, it does not ~uggest the advantages for using
a continuous stirred reactor for making peroxyacids of the
type disclosed herein uti]izing the sulfuric acid, water,
hydrogen peroxide reaction medium. The present inventors
have discovered that a continuous reactor can produce ali-
phatic diperoxyacids having significantly larger crystals
than those formed from a batch process. This allows for
the crystals to be collected more easily and economically
due to increased filtration rates.
It is therefore an object of the present invention
to provide a method for making diperoxyacids which have
increased crystal size.
This and other objects of the present invention will
: become apparent from the following description.
All percentages and ratios used herein are by weight
unless otherwise specified.
SUMMARY OF THE INVENTION
The present invention relates to a process for making
aliphatic diperoxyacids comprising continuously adding a
dibasic acid having from about 8 to about 16 carbon atoms,
sulfuric acid, hydrogen peroxide and water to a stirred
reactor. The diperoxyacid formed is continuously with-
drawn from the reactor to maintain a constant residence
time for the reactants in the reactor.
, ~ - 2 -
, . i
. , ,
More specifically, according to the invention there is
provided a continuous process ~or making diperoxyacids of
the formula
O O
Il 11 .
HOO - C ~ (CH2)n ~ C - OOH
wherein n is from about 6 to about 14, said diperoxyacids
having a crystalline form and an average crystal size
substantially greater than about 19 microns, comprising:
(a) continuously adding to a stirred reactor of tem-
perature from about 15C to about 45C the following
materials: (1) hydrogen peroxide; (2) water; (3) sulfuric
acid; and (~) a dibasic acid of the formula
O O
Il 11
HO - C - (CH2)n - C - OH
wherein n is from about 6 to about 1~; (b) continuously
withdrawing Erom the reactor diperoxyacid product ~ormed
as a result of the oxidation of the dibasic acid; (c)
filtering the diperoxyacid product; and (d)washing the
diperoxyacid product with water and drying it; wherein the
inlet flow rates to the reactor o~ sulfuric acid, hydrogen
peroxide and water are sufficient to maintain a liquid
concentration of about 60% to about 80% sulfuric acid,
about 0.5% to about 15% hydrogen peroxide, and about 5%
to about 39.5% water in the reactor.
DETAILED DESCRIPTION OF THE INVENTION
: ~ .
. The process of the present invention involves con-
tinuously adding an aliphatic, dibasic acid having from
about 8 to about 16 carbon atoms, sulfuric acid, hydrogen
; peroxide and water to a stirred reactor. The dibasic acid
is peroxidized to the diperoxyacid in the reactor which
peroxyacid then precipitates in crystalline formO The
.
- 2a -
lti3:~
crystalline product is continuously withdrawn from tlle
reactor to maintain a constant average residence time for
the reactants. The actual average residence time can be
established by controlling the reactant Eeed rates and
product withdrawal rate. It is therefore possible to vary
the average residence time from several minutes to several
hours depending on the actual design of the reactor. For
reasons of efficiency the residence time preferably should
be sufficient to allow for at least 80~ conversion of the
dibasic acid to the diperoxyacid.
The composition of the liquid, excluding diacids and
diperoxyacids, in the reactor is important in the forma-
tion of the diperoxyacid. In the present invention it
,.
.~ .
:
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has been found that the maintained liquid composition in the
reactor preferably comprises from about 60~ to about 80%
sulfuric acid, from about 0.5% to about 15% hydrogen peroxide
and from about 5% to about 39.5% water. Most preferably,
this liquid composition maintained in the reactor is from
about 60% to about 80% sulfuric acîd, from about 2% to about
15% hydrogen peroxide and from about 5% to about 38% water.
he ingredients used in the process of the present
invention are all readily available in commerce. Hydrogen
peroxide can be of any concentration, but is preferably from
about 35% to about 70%, while sulfuric acid is preferably
used in a concentration of from about 92% to about 98%. The
percentages of these materials in the reaction mixture
described above are based on pure materials.
The acids suitable for use herein are those
aliphatic dibasic carboxylic acids having from about 8 to
- about 16 carbon atoms. The unsubstituted acids have the
following general formula:
O O
HO - B R - C - OH
wherein R is an alkylene group containing from about 6 to
about 14 carbon atoms. Preferred R groups are of the formula
- (CH2)n~ wherein n is a number of from about 6 to about 14.
Especially preferred is dodecanedioic acid (n = 10).
The diperoxyacid formation reaction is as follows:
- 3a -
-
6;;~6
, '
o o
12S04
~IO C - (C~I2)n ~ C OH ~~ 2HZO2 ~
,
O O
11 ' 11 .... ', ''
HOO - C - (CE{z)n - C - ~OH -~ 2T~O
It is seen that for each mole of dibasic acid used t~o mole~
of hydrogen peroxide are required to form the diperoxyacid.
It is preferred, however, that an excess of hydroyen peroxid~
be used in amoun-ts ranging up to 5 times the stoichiomet~ic
re~uired amount.
The addition o the dibasic acid to the react~r can
be done in either of two distinc~ ways. In the firs~ wa~ the
3 di~asic acid is a~ded separately rom ~he other reac~n~. In
the second, preferred way, the dibasic acid is dissolved in
the sulfuric acid with the solution being added via one inlet
stream while aqueous hydrogen pero~ide is added as a second
inlet stream.
lS The size of the equipment required ~or the present
- process is easily determined by the s~iIled artisan when it
has been de,ermined that a particular pxoduction rate is
desired. The material of construction is not critical but
is preferably selected from the group consisting of glass,
Teflon~ stainless steel, tantalum, aluminu~ and porcelain
The present process can take the form of any continuous
stirred reactor. Two common forms o~ such reactors involve the
use of a stirred tank or a hi~h speed recycle reactor wherein
the mixin~ is the result of the action of a pump. In the latter
system the reactant streams are ~ed into a pump ratner than i~to
a m~xir.~ tc~n~;t the dipero ~acid prcduct is~i~hdra~,n frcm the p~ ar.d r~n
. ~ .' .
,
in-to a heat exchanger and part of the cooled product is
recycled to the pump. Each system has certain advantages
and may in fact be used together to obtain the benefits of
both.
Regardless of the particular process selected the
temperature maintained in the reactor is a critical element
in determining the rate and charact:eristics of the peroxida-
tion reaction. In the present invention it is preferred to
operate the reactor in the range of about 15 to about 45C.
Another element which plays an important role in
^ the reaction process is the mixing which takes place in the
reactor. It is desirable in a stirred tank reactor, for
maximum crystal size, to use low-shear mixing such as that
provided by a slowly moving paddle type agitator. High shear,
such as that supplied by a high speed radial turbine, results
in the crystals being reduced in size. The selection of a
pumping system in the high speed recycle process should also
be made so that crystal break up is minimized.
The cooling necessary to achieve the desired
temperature in either the stirred tank reactor or the recycle
process can be obtained in any convenient way. For example~
with the stirred tank cooling coils or a jacket in contact
with the tank surface may be employed.
As was indicated above, the different types of
continuous stirred reactors may be combined. Similarly the
reactor system may have included in it a portion of a plug
flow reactor. Such a combination allows for improved mixing
within the reactor, as well as helps to control particle size.
See, for example, Becker, G. W. and Larson, M.A., "Mixing
Effects in Continuous Crystallization," Chemical Engineering
Progress Symposium Series - Crystallization from Solutions
._.
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3~6
and Melts, Vol. 65.
Once the diperoxyacid product is removed Erom the
reactor system it must be filtered and washed. The choice
of an appropriate filter is dependent on the production rate
desired, as well as the crystal characteristics. As with the
parts of the reactor system, the skilled artisan, knowing
these facts, can easily select an appropriate filter.
The peroxyacids made usiny the process of the pre~
sent invention can be dried using conventional dryin~ tech-
niques with usual safeguards for handling peroxyacids beingobserved.
The continuous stirred tank reactor as described
above, when it is started up, is charged with some of the
diperoxyacid reaction product. After the reactor is opera-
tional a recycle stream may be used to supply part of the
reactant liquids.
In addition to providing larger crystals, the
continuous process herein can utilize faster reaction
conditions with fewer safety problems than is possible with
a batch reactor.
Compositions Containing the Peroxyacid Compounds
.....
The peroxyacid compounds made using the process of
the present invention can be used in a wide variety of
compositions. A preferred use is as a fabric bleaching
agent. To insure that compositions containing the peroxyacid
compounds are safe and effective, certain additives are
desirably present.
It is well documented in the peroxyacid literature
that peroxyacids are susceptible to a number of different
stability problems, as well as being likely to cause some
problems. Looking at the latter first, peroxyacids decompose
- - 6 -
; exothermally and when the material is in dry granular form
the heat generated must be controlled to make the product
safe. The best exotherm control agents are those which are
capable of liberating moisture at a temperature slightly
below the decomposition temperature of the peroxyacid
employed. U.S. Patent 3,770,816, November 6, 1973, to
- Nielsen, discloses a wide ~ariety of hydrated materials
which can serve as suitable exotherm control agents~ Included
among such materials are magnesium sulfate 7~12O, magnesium
formate dihydrate, calcium sulfate (CaSO4 2H2O), calcium
lactate hydrate, calcium sodium sulfate (CaSO4 2Na2SO~
; 2H2O), and hydrated forms of such things as sodium aluminum
sulfate, potassium aluminum sulfate, ammoniun aluminum
sulfate and aluminum sulfate. Preferred hydrated are
the alkali metal aluminum sulfates, particularly
preferred is potassium aluminum sulfate. Other preferred
exotherm control agents are those materials which lose water
as the result of chemical decomposition such as boric acid,
malic acid and maleic acid. The exotherm control agent is
preferably used in an amount of from about 100% to about
200~ based on the weight of the peroxyacid compound.
- The other problems faced when peroxyacid compounds
are used fall into the area of maintaining good bleach
effectiveness. It has been recognized that metal ions are
capable of serving as catalyzing agents in the degradation
of the peroxyacid compounds. To overcome this problem
chelating agents can be used in an amount ranging from 0.005%
to about 1.00% based on the weight of the composition to tie
up heavy metal ions. U.S. Patent 3,442,937, May 6, 1969, to
Sennewald et al., discloses a chelating system comprising
quinoline or a salt thereof, an alkali metal polyphosphate
and, optionally, a synergistic amount of urea. U.S. Patent
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~I _ ~4
i
2,838,459, June 10, 1958, to Sprout, Jr., discloses a ~ariety
of polyphosphates as stabilizing ayents for peroxide baths.
These materials are useful herein as stabilizing aids. U.S.
Patent 3,192,255, June 29, 1965, to Cann, discloses the use
of ~uinaldic acid to stabilize percarboxylic acids. This
material, as well as picolinic acid and dipicolinic acid,
would also be useful in the composi.tions of the present
invention. A preferred chelating system for the present
invention is a mixture of 8-hydroxyquinoline and an acid
polyphosphate, preferably acid sodium pyrophosphate. The
latter can be a mixture of phosphoric acid and sodium pyro-
phosphate wherein the ratio of the former to the latter is
from about 0.5:1 to about 2:1 and the ratio of the mixture
to 8-hydroxyquinoline is from about l:l to about 5:l.
In addition to the above-mentioned chelating systems
to tie up heavy metals in the peroxyacid compositions, coating
material may also be used to extend the shelf life of dry
granular compositions. Such coating materials may be, in
general, acids, esters, ethers and hydrocarbons and include
such things as wide varieties of fatty acids, derivatives of
fatty alchols, such as esters and ethers, derivatives of
polyethyleneglycols such as esters and ethers and hydrocarbon
oils and waxes. These materials aid in preventing moisture
from reaching the peracid compound. Secondly, the coating
material may be used to segregate the peracid compound from
other agents which may be present in the composition and
adversely affect the peracid's stability. When used in this
manner the coating may be used on both the peracid compound
and the other agent or either individually. The amount of
the coating material used is generally from about 2.5% to
about 15% based on the weight of the peroxyacid compound.
-- 8 --
16~
Additional agents which may be usecl to aid in
giving good bleaching performance include such things as pH
adjustment agents, bleach activators and minors such as
coloring agents, dyes and perfumes. Typical pH adjustment
agents are used to alter or mainta:Ln aqueous solutions of
the instant compositions within the 5 to 10 pH range in
; which peroxyacid bleaching agents are generally most useful.
Depending upon the nature of other optional composition
ingredients, pH adjustment agents can be either of the acid
or base type. Examples of acidic pH adjustment agents
designed to compensate for the presence of other highly
alkaline materials include normally solid organic and inorganic
acids, acid mixtures and acid salts. Examples of such acidic
pH adjustment agents include citric acid, glycolic acid,
tartaric acid, gluconic acid, glutamic acid, sulfamic acid,
sodium bisulfate, potassium bisulfate, ammonium bisulfate and
mixtures of citric acid and lauric acid. Citric acid is
preferred by virtue of its low toxicity and hardness se~ues-
tering capability.
` 20 Optional alkaIine pH adjustment agents include the
conventional alkaline buffering agents. Examples of such
buffering agents include such salts as carbonates, bicarbon-
ates, silicates, pyrophosphates and mixtures thereof. Sodium
bicarbonate and tetrasodium pyrophosphate are highly
preferred.
Optional peroxyacid bleach activators as suggested
by the prior art include such materials as aldehydes and
ketones. Use of these materials as bleaching activators is
described more fully in U.S. Patent 3,822,114j July 2, 1974,
to Montgomery.
A preferred dry, granular bleaching product
_ g _
.
: ,
96
employing the peroxyacid bleach of the present invention
involves combining the active peroxy compound with potassium
~ aluminum sulfate or boric acid and the acid pyrophosphate/
- 8-hydroxy~uinoline subse~uently coating this mixture with
mineral oil and agglomerating the coated particles with a
polyethylene glycol derivative. An alkaline pH adjustment
agent is then added to the agglomerated stabilized active
as a dry mix.
Optional ingredients, if utilized in combination
with the active peroxyacid of the instant invention to form
a complete bleaching product, comprise from about 20% to
about 99% weight of the total composition. Conversely,
the peroxyacid compound made using the process of the present
invention comprises from about 1~ to about 80% of the
composition.
The bleaching compositions of the instant invention,
particularly the dry granular version, can also be added to
and made a par-t of conventional fabric laundering detergent
compositions. Accordingly, optional materials for the
instant bleaching compositions can include such standard
detergent adjuvants as surfactants and builders. Optional
surfactants are selected from the group consisting of
organic anionic, nonionic, ampholytic, and zwitterionic
surfactants and mixtures thereof. Optional builder materials
include any of the conventional organic and inorganic builder
salts including carbonates, silicates, acetates, polycarboxy-
lates and phosphates. If the instant stabilized bleaching
compositions are employed as part of a conventional fabric
laundering detergent composition, the instant bleaching
agent generally comprises from about 1% to about 40% by weight
of such conventional detergent compositions. Conversely, the
-- 10 --
. ~
" ~
6~396
instant bleaching compositions can optionally contain from
about 60~ to about 99~ by weight of conventional surfactant
and builder materials. Further examples of suitable
surfactants and builders are given below.
Water-soluble salts of the higher fatty acids,
i.e., "soaps," are useful as the anionic surfactant herein.
This class of surfactants includes ordinary alkali metal
soaps such as the sodium, potassium, ammonium and alkanol-
ammonium salts of higher fatty acids containing from about 8
to about 24 carbon atoms and preferably from about 10 to about
20 carbon atoms. Soaps can be made by direct saponification
of fats and oils or by the neutralization of free fatty acids.
Particularly useful are the sodium and potassium salts of
; the mixtures of fatty acids derived from coconut oil and
tallow, i.e., sodium or potassium tallow and coconut soaps.
Another class o anionic surfactants includes
water-soluble salts, particularly the alkali metal, ammonium
and alkanolammonium salts, of organic sulfuric reaction
products having in their molecular structure an alkyl group
containing from about 8 to about 22 carbon atoms and a
sulfonic acid or sulfuric acid ester group. (Included in the
term "alkyl" is the alkyl portion of acyl groups.) Examples
of this group of synthetic surfactants which can be used in
the present detergent compositions are the sodium and potassium
alkyl sulfates, especially those obtained by sulfating the
higher alcohols ~C8-C18 carbon atoms) produced by reducing
the glycerides of tallow or coconut oil; and sodium and
potassium alkyl benzene sulfonates, in which the alkyl group
contains rom 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.
-- 11 --
.' , ~ . .
. .. :
i63~
.
Other anionic surfactant compounds useful herein
include the sodium alkyl glyceryl ether sulfonates, especially
those ethers or hi~her alchols derived from ~ low and coconut oil; sodium
coconut oil fatty acid monoglyceride sulfonates and sulfates;
and sodium or potassium salts of alkyl phenol ethylene oxide
ether sulfate containing about 1 to about 10 units of ethylene
oxide per molecule and wherein the alkyl groups contain
about 8 to about 12 carbon atoms~
Other useful anionic surfactants herein include
the water-soluble salts of esters of ~-sulfonated fatty acids
containing from about 6 to 20 carbon atoms in the ester group;
water-soluble salts of 2-acyloxy-alkane-1-sulfonic acids
: containing from about 2 to 9 carbon atoms in the acyl group
and from about 9 to about 23 carbon atoms in the alkane
moiety; alkyl ether sulfates containing from about 10 to 20
carbon atoms in the alkyl group and from about 1 to 30 moles
of ethylene oxide; water-soluble salts of olefin sulfonates
containing from about 12 to 24 carbon atoms; and ~-alkyloxy
alkane sulfonates containing from about 1 to 3 carbon atoms
in the alkyl group and from about 8 to 20 carbon atoms in the
alkane moiety.
Preferred water-soluble anionic organic surfactants
herein include linear alkyl benzene sulfonates containing
from about 11 to 14 carbon atoms in the alkyl group the
tallow range alkyl sulfates; the coconut range alkyl glyceryl
sulfonates; and alkyl ether sulfates wherein the alkyl moiety
contains from about 14 to 18 carbon atoms and wherein the
average degree of ethoxylation varies between 1 and 6.
Specific preferred anionic surfactants for use
herein include: sodium linear C10-C12 alkyl benzene
sulfonate; triethanolamine C10-C12 alkyl benzene sulfonate;
- 12 -
'~, .
.
1~16~
sodium tallow alkyl sulfate; sodium coconu-t alkyl glyceryl
ether sulfonate; and the sodium salt of a sulfated conden~
sation product of tallow alcohol with from about 3 to about
10 moles of ethylene oxide.
It is to be recognized that any of the foregoing
anionic surfactants can be used separately herein or as
mixtures.
Nonionic surfactants inc:Lude the water-soluble
ethoxylates of C10-C20 aliphatic alcohols and C6-C12 alkyl
phenols. Many nonionic surfactants are especially suitable
for use as suds controlling agents in combination with
anionic surfactants of the type disclosed herein.
Semi-polar surfactants useful herein include
water-soluble amine oxides containing one alkyl moiety of
from about 10 to 28 carbon atoms and 2 moieties selected from
the group consisting of alkyl groups and hydroxyalkyl groups
containing from 1 to about 3 carbon atoms; water-soluble
phosphine oxides containing one alkyl moiety of about 10 to
28 carbon atoms and 2 moieties selected from the group
' 20 consisting of alkyl groups and hydroxyalkyl groups containing
from about 1 to 3 carbon atoms; and water-soluble sulfoxides
containing one alkyl molety of from about 10 to 28 carbon
atoms and a moiety selected from the group consisting of alkyl
and hydroxyalkyl moieties of from 1 to 3 carbon atoms.
Ampholytic surfactants include derivatives of
aliphatic or aliphatic derivatives of heterocyclic secondary
and tertiary amines in which the aliphatic moiety can be
straight chain or branched and wherein one of the aliphatic
substituents contains from about 8 to 18 carbon atoms and at
least one aliphatic substituent contains an anionic water-
solubilizing group.
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'
Zwitterionic surfactants include dexi~atives of
aliphatic quaternary ammonium, phosphonium and sulfonium
compounds in which the aliphatic moieties can be straight or b~anched
chain, and wherein one of the aliphatic substituents contains
from about 8 to 18 carbon atoms ancl one contains an anionic
water-solubilizing group.
The instant granular compositions can also comprise
those detergency builders commonly taught for use in laundry
compositions. Useful builders herein include any of the
conventional inorganic and organic water-soluble builder salts, as well
as various water-insoluble and so-called "seeded" builders.
- Inorganic detergency builders useful herein include,
for example, water-soluble salts of phosphates, pyrophosphates,
orthophosphates, polyphosphates, phosphonates, carbonates,
bicarbonates, borates and silicates. Specific examples of
inorganic phosphate builders include sodium and potassium
tripolyphosphates, phosphates, and hexametaphosphates. The
polyphosphonates specifically include, for example, the
sodium and potassium salts of ethylene diphosphonic acid, the
sodium and potassium salts of ethane l-hydroxy-l, l-diphos-
phonic acid, and the sodium and potassium salts of ethane-
1,1,2-triphosphonic acid. Examples of these and other
phosphorus builder compounds are disclosed in U.S. Patents
3,159,581; 3,213,030; 3,422,021; 3,422,137; 3,400,176 and
3,400,1~8. Sodium tripolyphosphate is an especially preferred,
water-soluble inorganic builder herein.
Non-phosphorus containing sequestrants can also be
selected for use herein as detergency builders. Specific
examples of non-phosphorus, inorganic builder ingredients
include water-soluble inorganic carbonate, bicarbonate, borate
and silicate salts. The alkali metal, e.g., sodium and
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~ - - : . , , . . . : .
6~
potassium, carbonates, bicarbonates, borates (Borax) and
silicates are particularly useful herein.
Water-soluble, organic builders are also useful
herein. For example, the alkali metal, ammonium and
substituted ammonium polyacetates, carboxylates, polycarboxy-
lates, succinates, and polyhydroxysulfonates are useful
builders in the present compositions and processes. Specific
examples of the polyacetate and polycarboxyla-te builder salts
include sodium, potassium, lithium, ammonium and substituted
ammonium salts of ethylene diamine tetraacetic acid, nitrilo-
triacetic acid, oxydisuccinic acid, mellitic acid, benzene
polycarboxylic acids, and citric acid.
Highly preferred non-phosphorous builder materials
(both organic and inorganic) herein include sodium carbonate,
sodium bicarbonate, sodium silicate, sodium citrate, sodium
oxydisuccinate, sodium mellitate, sodium nitrilotriacetate,
and sodium ethylenediaminetetraacetate, and mixtures thereof.
Another type of detergency builder material useful
in the present compositions and processes comprises a water-
soluble material capable of forming a water-insoluble
reaction product with water hardness cations in combination
with a crystallization seed which is capable of providing
growth sites for said reaction product.
Specific example of materials capable of forming
the water-insoluble reaction product include the water-
soluble salts o~ carbonates, bicarbonates, sequicarbonates,
silicates, aluminates and oxalates. The alkali metal,
especially sodium, salts of the foregoing materials are
preferred for convenience and economy.
; 30 Another type of builder useful herein includes
various substantially water-insoluble materials which are
- 15 -
,. ,
,
capable of reducing the hardness content of laundering
liquors, e.g., ~y ion-exchange processes. Examples of such
builder materials include the phosphorylated clothes disclosed
in U.S. Patent 3,424,545, Bauman, issued January 28, 1969.
The complex aluminosilicates, i.e., zeolite-type
materials, are useful presoaking/washing adjuvants herein in
that these materials soften water, i.e., remove Ca hardness.
Both the naturally occurring and synthetic "zeolites", espe-
cially zeolite A and hydrated zeolite A materials, are useful
for this builder/softener purpose. A description of zeolite
materials and a method of preparation appears in Milton,
U.S. Patent 2,882,243, issued April 14, 1959.
Composition Preparation
The bleaching compositions of the instant invention
are prepared in any conventional manner such as by admixing
ingredients, by agglomeration, by compaction or by granulation
in the case of the dry granule form. In one method for
preparing such compositions, a peroxyacid water mixture
containing from about 50% by weight to about 80% by weight of
water is ~ombin~d in proper proportions with any optional
components to be utilized within the bleaching granules
themselves. Such a combination of ingredients is then
thoroughly mixed and subsequently run through an extruder.
Extrudate in the form of noodles is then fed into a spheronizer
(also known by the trademark, Marumerizer) to form approxi-
mately spherical particles from the peroxyacid-containing
noodles. The bleach1ng granules can then be dried to the
appropriate water content. Upon leaving the spheronizer,
such particles are screened to provide uniform particle size.
Bleaching granules prepared in this manner can then
be admixed with other granules of optional bleaching or
- 16 -
63gfi
detergent composition materials. Actual particle size of
either the bleach-containing granules or optional granules
of additional material is not crit:ical. If, however~
compositions are to be realized having commercially accept-
able flow properties, certain granule size limitations are
highly preferred. In general, all granules of the instant
compositions preferably range in size from about 100 microns
to 3000 microns, more preferably from about 100 microns to
1300 microns.
Additionally, flowability is enhanced if particles
of the present invention are of approximately the same size.
Therefore, preferably the ratio of the average particle sizes
of the bleach-containing granules and optional granules of
other materials varies between 0.5:1 and 2.0:1.
i Bleaching compositions of the present invention are
- utilized by dissolving them in water in an amount sufficient
to provide from about 1.0 ppm to 100 ppm available oxygen in
solution. Generally, this amounts to about 0.01% to 0.2~ by
weight of composition in solution. Fabrics to be bleached
are then contacted with such aqueous bleaching solutions.
The process of the instant invention is illustrated
by the following example:
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~V63~96
EXAMPLE I
The advantage for the continuous process of the
present invention over a batch process is demonstated in the
experiment described below.
A. Diperoxydodecanedioic acid is made using a batch
reactor equipped with a stirrer wherein (a) 50 grams
of dodecanedioic acid is dissolved in 213.6 grams of
97% sulfuric acid with the solution being cooled to
10C; (b) a hydrogen peroxide mixture is prepared
by mixing together, while keeping the temperature
under 27C, 116.7 grams of 67.8% hydrogen peroxide,
57.5 grams of water and 213.3 grams of 97% sulfuric
acid; (c) the mixture of (b) is cooled to 6C; and
(d) the solution of (a) and the mixture of (b) are
mixed together quickly and the mixture is maintained
at a temperature of 35C for a period of one hour.
The diperoxydodecanedioic acid formed precipitates
and the precipitate is washed with water and collected
by means of filtration. The collected crystals are
evaluated for particle size, filtration rate and
available oxygen.
B. A second batch of diperoxydodecanedioic acid which is
seeded is made using a batch reactor equipped with a
stirrer wherein (a) and (b) as described above are
duplicated. To the peroxide mixture (b) are added 200
grams of the reaction product from A at a temperature
of about 9C with the final mixture temperature going
to about 30C. To this mixture is added the dodec-
anedioic acid/sulfuric acid solution as described in
(a) above and the temperature of the reaction mix
- 18 ~
.
3~
is maintalned at about 35C for one hour. The
dipexoxyacid formed is filtered, washed with water
and analyzed for particle size, filtration rate
and available oxygen.
C. A continuous stirred tank reaction is carried out
by continuously feeding to a reactor similar to the
batch reactors the ~ollowing two streams: (a) 16.3
g/min. of a solution containing 10.4~ dodecanedioic
acid and 89.6~ sulfuric acid (97%); and (b) 5.94
g/min. of a mixture containing 45.2% hydrogen per-
oxide and 54.8~ water. The reactor temperature is
increased from 20C to about 35C during the first
90 minutes and is maintained at about 35C for
another 210 minutes. The diperoxyacid product is
continuously withdrawn from the reactor vessel,
filtered, washed and analyzed. The rate of product
removal is such that the average residence time
in the reactor is about 56 minutes. The reactor
vessel at the start of the reaction is filled with
- 20 reaction product which has been formed using a
batch reactor as in A above.
The increase in crystal size for the continuous
reactor is shown in-the following table.
.
., - 19 -
;-
~1~6~96
COMPARISON OE BATCH AND CONTINUOUS REACTIONS
Batch Batch
Continuous Unseeded Seeded
Reaction Temperature, C 35 35 35
Premix Concentration*
Sulfuric acid 68.9 68.9 68.9
Hydrogen Peroxide 13.1 13.1 13.1
Water 18.0 18.0 18.0
Reaction Time, Minutes 56 (average 60 60
residence
Product analysis time)
Final available
oxygen level, ~ 11.4 11.4 11.2
Average crystal size, 47 14 19
micron
Filtration rate, 6.2 0.26 1.1
g filtrate/min.
cm2/cm. of filter
cake thickness
*Concentration of the liquid phase (excluding thedodecanedioic acid) entering the reactor prior to reaction.
It is seen that the continuous process yields larger,
more easily filtered, crystals than either a conventional
batch reaction or a batch reaction which has been seeded with
diperoxyacid.
Results similar to those give above are obtained
when the dibasic acid is another acid selected from the group
consisting of acids having the structure
O O
11 11 .
HO - C - (CH2)n - C - OH
where n is a number from about 6 to about 14. (Dodecanedioic
acid has n = 10.)l
- 20 -
. ~,.
