Note: Descriptions are shown in the official language in which they were submitted.
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Controlled Foam Aqueous Quaternary Ammonium and Phosphonium Compositions
FIELD OF THE INVENTION
This invention relates to a method for controlling foam formation in aqueous
systems
containing biocidal quaternary ammonium and/or phosphonium compounds
("quats").
This invention also relates to low foam aqueous formulations comprising
quaternary
ammonium and/or phosphonium compounds and the use of said formulations
compounds
in a method for killing or inhibiting the growth of microorganisms, algae and
fungi.
BACKGROUND OF THE INVENTION
Several quaternary ammonium and phosphonium compounds ("quats") exhibit marked
biocidal activity and, consequently, have been used as active ingredients in
disinfectants,
preservatives, or other compositions for killing or controlling the growth of
microorganisms, such as bacteria or viruses, as well as algae and fungi for
many years.
However, since many of those quats have also surfactant properties, their use
in aqueous
systems is often impaired by intensive foaming even at low quat concentrations
in the ppm
range, which is particularly detrimental in applications where aqueous systems
are
agitated while being exposed to the atmosphere, such as swimming pool or spa
waters or
waters in cooling towers.
SUMMARY OF THE INVENTION
Applicants have found that the addition of at least one anionic surfactant to
an aqueous
system containing at least one biocidal quaternary ammonium and/or phosphonium
compound in an amount corresponding to a molar ratio of anionic surfactant to
quaternary
ammonium and/or phosphonium compound of from 0.001 to 0.2 (i.e., 0.001:1 to
0.2:1),
preferably from 0.001 to 0.09, substantially reduces the volume and lifetime
of foam
formed during the use of the aqueous system.
As anionic surfactants are known to decrease the biocidal efficacy of
quaternary
ammonium compounds, the observed foam reduction achieved by addition of
anionic
surfactants at much less than a molar equivalency is important from the quat
performance
perspective. Since only small amounts of e.g. 0.1 or 0.02 molar equivalents of
anionic
surfactant are required, the compositions retain about 90 or 98 percent,
respectively, of
their active quat concentrations.
In a more preferred embodiment, the molar ratio of anionic surfactant to
quaternary
ammonium and/or phosphonium compound is from 0.001 to 0.05.
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Preferably, the at least one quaternary ammonium and/or phosphonium compound
is
selected from
(1) a compound having the formula [QR1R2R3R4] X- (I), wherein Q is
nitrogen or
phosphorus, R1 and R2 are independently unsubstituted or hydroxy-substituted
linear or branched C1-4 alkyl; -(CH2CH20)mCH2CH2OH, or
-(CH2CH(CH3)0)111CH2CH(CH3)0H, where m in each molecule independently is
an integer from 1 to 10;
R3 is an optionally substituted benzyl, ethylbenzyl, naphthylmethyl, or linear
or
branched C6-22 alkyl group;
R4 is an optionally substituted benzyl, ethylbenzyl, methylnaphthyl, or linear
or
branched C1-22 alkyl group or -R5(0)1,(C6H4)R6, wherein n is 0 or 1;
R5 is substituted or unsubstituted C1-8 alkanediyl or -(CH2)p-0-(CH2)q-
wherein p
and q independently are integers from 1 to 8;
R6 is hydrogen or a substituted or unsubstituted, linear or branched C1-12
alkyl
group; and X- is a monovalent or one equivalent of a polyvalent anion;
(ii) a compound having the formula Ri9R20R21R22Q+ --
A (II), wherein Q is nitrogen or
20, -=-.21,
phosphorus, R19, R and R22 are independently linear, branched,
cyclic or
any combination thereof saturated or unsaturated hydrocarbyl groups, X- is a
monovalent or one equivalent of a polyvalent anion, and the sum of the carbon
atoms numbers of R19, R20, -21
K and R22 ranges from 10 to 50;
(iii) a polymeric quaternary ammonium or phosphonium biocide; and
(iv) a mixture of two or more quaternary compounds of any of (i) to (iii).
More preferably, the quaternary ammonium and/or phosphonium compound has the
formula [QR1R2R3R4J4 X- (I), wherein Q is as defined above, both R1 and R2 are
C1-4
alkyl, R3 is a linear or branched C6-22 alkyl, R4 is benzyl or a linear or
branched C1-22 alkyl
and X- is chloride.
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Still more preferably, the quaternary ammonium and/or phosphonium compound has
the
formula [QRIR2R3R4]+ X- (I), wherein Q is as defined above, both RI and R2 are
methyl,
R3 is a linear or branched C6-22 alkyl, R4 is benzyl or a linear or branched
C6-22 alkyl and
X- is chloride.
Most preferably, Q is nitrogen.
Particularly preferred are ammonium and phosphonium compounds such as
alkyldimethyl-benzylammonium chloride or tributyl-tetradecylphosphonium
chloride.
In another preferred embodiment, X- in formula (I) and/or (II) is selected
from the group
consisting of Y2CO3-, HCO3and OH-.
In still another preferred embodiment the at least one anionic surfactant is a
sulfonate.
In another preferred embodiment the at least one anionic surfactant is a
diester.
In a particularly preferred embodiment, the at least one anionic surfactant is
selected from
the group consisting of diamyl sulfosuccinate, dihexyl sulfosuccinate, dioctyl
sulfosuccinate, ditridecyl sulfosuccinate, the potassium, sodium and calcium
salts of any
of the foregoing and any mixture of any of the foregoing sulfosuccinates and
salts.
In one most preferred embodiment, the at least one anionic surfactant is
selected from the
group consisting of dihexyl sulfosuccinate and the potassium, sodium and
calcium salts
thereof sulfonate.
In another most preferred embodiment, the at least one anionic surfactant is
selected from
the group consisting of dioctyl sulfosuccinate and the potassium, sodium and
calcium salts
thereof
In still another most preferred embodiment, the at least one anionic
surfactant is selected
from the group consisting of diamyl sulfosuccinate and the potassium, sodium
and
calcium salts thereof.
Of the above sulfosuccinate salts, the sodium salts are particularly
preferred.
The above sulfonates have been observed to substantially reduce foaming while
maintaining a high level of quat activity.
Preferably, the aqueous system contains from 0.1 to 100 ppm, more preferably
from 0.5 to
50 ppm, of the biocidal quaternary ammonium and/or phosphonium compound.
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Another object of the invention is a low foam formulation comprising at least
one biocidal
quaternary ammonium and/or phosphonium compound and at least one anionic
surfactant,
wherein the molar ratio of anionic surfactant(s) to quaternary ammonium and/or
phosphonium compound(s) is from 0.001 to 0.2, preferably from 0.001 to 0.09
and more
preferably from 0.001 to 0.05.
Preferably, the low foam formulation comprises 5 to 80 wt.%, more preferably
10 to 50
wt.%, based on 100 wt.% total formulation, of the at least one biocidal
quaternary
ammonium and/or phosphonium compound.
The low foam formulations of the present invention are stable single phase
clear solutions.
Preferably the low foam formulation contains at least one performance additive
such as a
dye or perfume.
Still another object of the invention is a method for killing or inhibiting
the growth of
microorganisms, zooplankton, algae and/or fungi comprising applying the above
formulations to an aqueous system or to a porous or hard surface.
In a preferred embodiment the porous or hard surface is wood, metal or
plastic.
In another preferred embodiment the formulation is used as a wood
preservative.
In still another preferred embodiment the formulation is used as a
disinfectant or sanitizer
for hard surfaces.
In yet another preferred embodiment the aqueous system is selected from the
group
consisting of cooling waters, waste waters, waters used on oil fields for
injection, test or
recovery purposes, recreational pool or spa waters, ballast water, and pulp or
papermaking
slurries.
Most preferably, the aqueous system is cooling water, ballast water or
recreational pool or
spa water.
Particularly preferred is the application as algaecides in pool or spa waters.
Preferably, the aqueous system contains from 0.1 to 100 ppm, preferably from
0.5 to 50
ppm, of the biocidal quaternary ammonium and/or phosphonium compound.
Exemplary Embodiments of the Invention
The invention is further illustrated by the following non-limiting examples.
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Examples
Method:
Test solutions were prepared from the selected quaternary ammonium compounds
and the
selected anionic surfactants in 20 C tap water (pH = 7-8, Total Hardness =
160-300 ppm
5 as CaCO3 and Total Alkalinity = 150-250 ppm as CaCO3). 150 mL of each
test solution
was added to a 250 mL stoppered graduated mixing cylinder, the solution was
agitated by
inverting the cylinder ten times and the foam volume measured immediately
after
agitation and again after 30 seconds settling time. Also measured was the time
for total
collapse of the foam ("time to no foam"). All quat concentrations in ppm or
percent are on
a weight basis and refer to the actual content of active ingredient, unless
otherwise
indicated.
Example 1 (Reference Example)
An alkyl (67% C12, 25% C14, 7% C16, 1% C8,10318) dimethylbenzylammonium
chloride
(ADBAC; Barquat 50-65B, Lonza Inc., Allendale, NJ) was selected as a
representative
quaternary ammonium compound for foam evaluation. As shown in Table 1 below,
ADBAC produced a substantial amount of foam, generating an initial foam volume
of 25
mL and maintaining 10 mL of foam after 30 seconds. As a comparison, the
foaming
behavior of the polymeric
quat
poly[oxyethylene(dimethyliminio)ethylene(dimethyliminio)ethylene dichloride]
(WSCP;
Buckman Laboratories International, Inc., Memphis, TN) was also tested.
Example 2
The effect of the anionic surfactant sodium dioctyl sulfosuccinate (NaDOSS) on
ADBAC
foaming was determined as described above. The results are shown in Table 1
below. The
addition of only a 0.1 molar equivalent of NaDOSS relative to the active quat
reduced the
initial foam volumes by 85 percent from 25 mL to 4 mL. Even the application of
only a
0.02 molar equivalent of NaDOSS resulted in merely 6 mL initial foam volume
and
complete foam loss within 10 seconds.
Example 3
The ability of NaDOSS to control foam at low concentrations of quaternary
ammonium
compounds, as they are frequently utilized in water treatment applications
such as
swimming pool algaecides, was tested at quat concentrations of 2 ppm using the
methodology of Example 2. For comparison purposes one test was performed
without
addition of NaDOSS. The results are shown in Table 1 below. It has been found
that
NaDOSS concentrations as low as 0.05 ppm can control foaming at 2 ppm quat
concentration.
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Example 4
The alternative anionic surfactants sodium dihexyl sulfosuccinate (NaDHSS) and
sodium
ditridecyl sulfosuccinate (NaDTSS) were also tested as foam reducing agents
using the
methodology of Example 2. The results are shown in Table 1 below. It has been
found that
NaDHSS concentrations as low as 1.1 ppm controlled foaming of 10 ppm quat
(corresponding to a molar ratio of anionic surfactant to quat of 0.10) while
concentrations
as low as 0.2 ppm still showed a small effect. Similar results have been
obtained with
NaDTSS at concentrations of 1.7 ppm (corresponding to a molar ratio of anionic
surfactant to quat of 0.10) and 0.4 ppm, respectively. NaDHSS was preferred as
it
produced clear solutions at all tested concentrations.
Table 1
Foam Volume
Quat Sulfonate
Sulfonate/Quat [mLl
.Time to No
Example No. -
Amount Amount
Molar Ratio.Foam Is]
Type Type Intial 30 s
IPP1111 lIVIIII ,
1 50-65B 10 ¨ ¨ 0 25 10 _ >30
-
1 WSCP 10 ¨ ¨ 0 0 0 <1
2 50-65B 10 NaDOSS 1.3 0.1 4 0 5
_
2 50-65B 10 NaDOSS 0.26 0.02 6 0 10
3 50-65B 2 ¨ ¨ 0 20 0 20
3 50-65B 2 ,NaDOSS 0.05 0.02 10 , 0 , 5
4 50-65B 10 NaDHSS 1.1 0.1 10 0 8
4 50-65B 10 NaDHSS 0.2 , 0.02 20 4
>30
_
4 50-65B 10 NaDTSS 1.7 0.1 10 0 , 4
_ _
4 50-65B 10 NaDTSS 0.4 0.02 20 2 >30
Example 5
As shown in the preceding examples, NaDOSS can be applied separately to
quat-containing solutions to achieve the desired foam reduction. However, for
practical
reasons, in particular ease of application, it is desirable to provide single
formulations
(concentrates) containing the quats and the anionic surfactants in an
optimized molar ratio.
Therefore the phase stability of two formulations containing Barquat 50-65B
and
NaDOSS was tested. The results are shown in Table 2 below.
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Table 2
NaDOSS/Quat Molar Quat Content NaDOSS Content Appearance
Ratio 110,61 PA]
0.02 49.2 1.2
Single phase, clear
0.10 46.1 50.8
Single phase, clear
It has been found that clear phase-stable formulations containing NaDOSS and
ADBAC in
molar ratios of 0.02 and 0.10 can be prepared. Test solutions with 10 ppm quat
were
prepared from these formulations and showed essentially the same foaming
behavior as
those of Example 2.
Example 6
Sodium dioctyl sulfosuccinate (NaDOSS) and sodium dihexyl sulfosuccinate
(NaDHSS)
were tested in a dynamic recirculation foam test designed to simulate cooling
applications.
The dynamic foam test consisted of recirculating a 1.5 liter water sample
through a large
graduated cylinder at a flow rate of 5.7 liter/min (1.5 GPM). The water
conditions were:
total hardness (as CaCO3) 280 ppm, total alkalinity (as CaCO3) 164 ppm,
temperature 22
C, and pH = 7.3. Master solutions of the test formulations were added as
necessary to
achieve the reported concentrations. The results are compiled in Table 3
below.
Table 3
Sample Stabilized Foam Height After 5 Minutes (cm)
LF 7.25-8.0
LF + 0.02 mol NaDOSS 4.0
LF + 0.02 mol NaDHSS 6.0
Both tested compounds significantly reduced the foaming properties of 90 ppm
active
dioctyldimethylammonium chloride (Bardac LF 18, Lonza Inc.). As shown in
Table 3,
the addition of NaDOSS at a molar ratio (sulfosuccinate/Bardac LF 18) of 0.02
provided
a 50% foam reduction, from 8 cm to 4 cm, while addition of NaDHSS at the same
molar
ratio provided a 25% foam reduction.
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Example 7
The phase stability of two formulations containing Bardac LF 18 and NaDOSS
were
tested. As shown in Table 4 below, formulations containing NaDOSS at molar
ratios of
0.02 and 0.05 are compatible, providing clear, single phase solutions.
Table 4
NaDOSS/Quat Molar Quat Content NaDOSS Content Appearance
Ratio f%1 [0,4,1
0.02 51.0 1.5 Single phase,
clear
0.05 50.0 3.6 Single phase,
clear
