Note: Descriptions are shown in the official language in which they were submitted.
~2~`2~ 7
PLANT BROWTH REGULATOR DI~PERSIONS
Field of Invention
This invention relates to dispersion~ of
plant growth regulating compounds. More
particularly it relates to water and oil
formulations containing 2-haloethyl phosphonic acid
compounds which are stable for extended periods of
time over a wide range of a~bient temperatures.
Backqround of the Invention
The ability of 2-haloethyl phosphonic acid
compound~ to regulate plant growth is well known and
is described for example in U.S. Patents No.
3,B79,188; 4,144,0~6, 4,240,819; 4,352,689:
4,374,661; and 4,401,454. These phosphonic acid
plant yLowth r~ju~ators, whe.l applied ~o plan~s,
elicit a variety of different responses, such as
increased yields, faster and more uniform ripening
of fruit, induction of antilodging effects, breaking
of apical dominance and the like, collectively
referred to as ethyle~e or ethylene-type responses.
The preerred and most widely used
phosphoric acid plant growth regulator compound is
2-chloroethylphosphonic acid which is known by the
generic name "ethephon". Ethephon is normally
stored in solution of relatively high concentration
for reasons of convenience and to minimize
degradation which begins to occur at pH levels above
about pH 5. In concentrated form ethephon exhibits
a pH of about 1Ø The concentrated solution is
customarily diluted prior to application to plants
at concentrations which exhibit a pH of about 3.5.
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The most commonly used solutions of
ehtephon for plant treatment are aqueous solutions
which are applied by conventional spray equipm~nt.
However, newer methods of application such as
ultra-low volume (ULV) spray apparatus, work more
effectively with non-aqueous solutions of the active
chemical with oil based formulations being most
preferred. Oil-based formulations of ethephon have
the added advantage of better penetration of plant
tissue than aqueous formulations.
A particular problem which it is sought to
overcome by this invention is the rapid evaporation
of water from aqueous formulations of ethephon which
sometimes occurs when aqueous formulations of
ethephon are applied through ULV apparatus. Such
evaForation is so rapid that in some inst?r.ces cnlv
the dry active reaches the plant.
The preparation of an oil-based formulation
of such phosphonic acid plant growth regulators is
therefore desirable both for improved plant tissue
penetration and to permit application of these plant
growth regulators with ULV apparatus. However,
formulation of the phosphonic acid directly in an
oil diluent is disfavored since the production of
such formulations requires the use of essentially
anhydrous phosphonic acid plant growth regulator.
These strongly acidic phosphonic acid compounds are
extremely hygroscopic and hence the anhydrous
product is difficult and costly to prepare and
dificult to maintain.
Formulations of aqueous solutions of
agricultural chemicals in an oil base are known in
D-14,04G
~L2~ 7
the art. Preparation of these emulsions or
dispersions i6 accomplished by mixing the desired
oil, water, active ingredient and an emulsifier in
appropriate amounts to achieve the desired
formulation. Such emulsion compositions ar~
typically 30-80% by weight oil and 10-40% water.
The emulsifier is present in smaller amounts, seldom
exceeding 15% by weight of the final composition and
more often at concentrations of 4-10%.
The preparation of chemically stable oil
emulsions of the phosphonic acid growth regulators
has proven difficult due to the low pH exhibited by
these compounds. This low pH encourages the
degradation of emulsifiers which rapidly erodes the
stability of the emulsion and leads to phase
sepa-a~.-ion. This severe'y 'imits ~.he vtility of
these emulsions as spray formulations since phase
separation of the spray formulation rPsults in poor
dispersion of phosphonic acid plant growth regulator
in the target area.
- Separation of formulation components may
also cause the formation of solids which could clog
the spray equipment. Acidic elements of the
formulation, which are safe when dispersed in the
oil carrier, can also cause rapid corrosion of spray
equipment if the phases separa~e.
Summary of the Invention
This invention provides dispersions
containing 2-haloethyl phosphonic acid plant growth
regulators that are stable and particularly well
suited for use with ~LV apparatus. They are
prepared by mixing an a~ueous solution of the
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2-haloethyl phosphonic acid plant growth regulator
with an oil and a substantial amount of ~urfactant.
In some eompositions a co-surfactant is also presen~.
It is a principal object of this invention
to provide oil-based compositions that contain
2-haloethyl phosphonic acid plant growth regulating
compounds, that are thermodynamically and chemically
stable and that can be applied with ULV equipment.
It is a further object to prepare oil-based
formulations of these compounds that are stable for
period~ on the order of at least two years at
ambient temperatures (i.e., ranging from as low as
about -10C to as high as about 35C).
It is a further object to prepare oil-based
dispersions of 2-haloethyl phosphonic acid plant
growth regulators that can be easilv cle2nsed from
storage vessel~ and application equipment with a
water rinse.
Detailed Description of the Invention
This invention provides a stable plant
growth regulating composition which comprises a
dispersion, haviny a Brookfield viscosity of less
than 800 cps and containing micelles no larger than
about 300 nm, of:
(a) from about ten percent (10%) to about
fifty percent (50%) by weight of a phosphonic acid
plant growth regulator; and
(b) from about twenty percent (20%) to
about sixty percent (60%) by weight of liquid which
is substantially immiscible with water, which is not
a solvent for said active compound, and which is
6table at the pH of the active compound; and
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(c) from about five percent (5%) to about twenty-
five percent (25~) by weight water; and
(d) from about ten percent (10%) to about forty
percent (40%) by weight hydrophobic surfactant or surfactant
mixture which is stable at pH of said active compound.
The term phosphonic acid plant growth regulator, as
used herein, includes not only 2-haloethyl phosphonic acid
compounds such as ethephon but also all derivatives thereof
which act as plant growth regulators.
O The phosphonic acid plant growth regulators suitable
for use in this invention are described in U.S. patents Nos.
3,879,188; 4,374,661; 4,401,454; ~,240,819; and 4,352,689.
The preferred phosphonic acid plant growth regulator
is 2-chloroethyl phosphonic acid, generically known by the
generic name "ethephon". Ethephon is available as an
aqueous concentrate of five to ninety-five percent.
Preferred concentrates contain from about sixty to about
eighty percent by weight of phosphonic acid plant growth
regulator.
The terms: A "dispersion," "colloid" and "emulsion"
as used herein describe macroscopically homogeneous but
microscopically heteroyeneous mixtures of two or more finely
divided phases (i.e., solid, liquid or gas). The
dispersions of this invention typically comprise liquid~
liquid mixtures, one of the liquids being an aqueous
solution of growth regulating compound, the other being an
rn/
.~
, . . . .
~ - 6 -~8~9r~
"oil", i.e., a liquid substantially immiscible with
water. The term "liquid ~ubstantially immiscible
with water" as used herein includes all liquids
which, when mixed with water in the ratios described
in this inven~ion, will separate into two discrete
phases after equilibration, absent agitation or
presence of emulsifier.
Liquid-liquid dispersions consist of a
first liquid, which forms the continuous phase in
which micelles containing droplets of a ~econd
liquid, the discontinuous phase, are uniformly
distributed. The term "micelle" refers to a
molecular aggregate in which each surfactant
molecule contains functional groups that interact
independently with the oil and with the water. The
functional group that interacts with the water is
known as a hydrophile (i.e., water lover) or
lipophobe (i.e., oil hater) while the group that
bonds to the oil phase is designated a lipophile
(i.e., oil lover) or hydrophobe (i.e., water
hater). If water is the continuous phase and oil
the secondary phase trapped in micelle centers, the
dispersion is an oil-in-water (O/W) emulsion. In a
water-in-oil (W/O) emulsion, also known as an
"invert emulsion", the oil is the continuous phase
and water ~he secondary phase. The micelles in such
invert emulsions are "invert micelles"; the
hydrophilic component of the surfactant surrounds
the aqueous center while the hydrophobic component
interacts with the surrounding oil.
The formulations of this invention are
microemulsions which have a low viscosity, and are
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thermodynamically and chemically s~able. The ~mall
micelle size, preferably ranging from abou~ 10 to
about 200 nm, produces a minimal amount of light
scattering. Therefore most of the microemulsions of
this invention are transparent, absent incorporation
of a reagent or additive that is colored. In some
instances the micelles of this formulation may be as
large as about 300 nm in diameter, which may cause
light scattering and render the formulations
translucent.
The formulations of thi~ invention must
have sufficiently low viscosities to permit spraying
onto target plants by conventional spray apparatus,
and preferably by ULV equipment. A wide range of
viscosities are useEul depending upon the apparatus
used. Brookield viscosities of greatsr than 800
cps are considered too thick for any conventional
spray applicators and if the formulation is to be
used in ULV equipment the viscosity preferably
should not exceed about 300 cps and more preferably
should be less than 100 cps. (The viscosities
referred to are measured at 25C with a Brookfield
Viscometer Model RVT using a number 4 spindle at 20
rpm.)
The concentration of phosphonic acid plant
growth regulator compound used in the formulation of
this invention preferably ranges from about ten
percent (10%) to about fifty percent (50%) by
weight, depending primarily upon the intended use of
the formulation, particularly the plant to which it
is applied and the specific plant growth response
desired.
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In the microemulsion formulations of this
invention the continuous phase is an oil, i.e.,
liquid which is sub6tantially immiscible with water,
which i5 not a 601vent for the active compounds
employed, and which is stable at pH of the growth
regulator. While ~ome minor degree of intermixing
may be tolera~ed, the oil and water must be
sufficiently immiscible, in the ratio of water to
oil u6ed in a particular dispersion, that two
discrete microscopic phases in the formulation will
survive for extended periods of time over a
temperature range of from about -20C to about +50C
in the presence of all the ingredients incorporated
into the formulation. Preferably, the dispersion
should remain intermixed for at least two years in a
temperature range of from -109C to ~35C. ~s a
general rule, the oil ~hould not be soluble more
than 1% by weight in water. In addition, the
selected oil must be ~table in the acidic medium
produced by the phosphonic acid ~ompound, which may
be as low as 0.5 pH. Compounds are not desirable
for use as the oil in this invention which are
sensitive to acid hydrolysis or protonation These
compounds include esters, amines and pyridinium
compounds. Long-term stability of two years or
more, especially at elevated temperatures, is
dificult to achieve with such acid sensitive oil~.
The oil employed should also be essentially
non-phytotoxic to the target plants at the applied
concentration. The oil should either be non-toxic
or, if toxic, reguire a time to kill or injure the
D-14,046
-` ~ 2~ J~
plant that exceeds the useful or remaining growing
~eason of ~h~ plant. Further, if the formulation is
to be used with ULV equipment, the oil is pref~rably
sufficiently non-evaporative so that ~prayed
droplets of formulation reach the target plants in
liquid form. The vapor pressure of the oil used for
ULV applications must therefore be conæidered.
Representative of the oils useful in ~he
formulations of this invention are aromatic
hydrocarbons; extracts derived from natural sources;
aliphatic hydrocarbons containing up to thirty
carbon atoms, up to four non-adjacent double bonds,
and up to four halogen, carboxyl or hydroxyl
substituents (provided, of course, that the compound
is a liquid immiscible with water). Mixtures of
these oils can also be used. Especially preferred
oils include mixtures of paraffins or isoparaffins;
benzene or alkylbenzenes containing up to four C
to C4 alkyl ~ub6tituents; fatty acids containing
from about twelve to about thirty carbon atoms, such
as oleic acid and linoleic acid, and their
triglyceride derivatives; and extracts derived from
na~ural sources, e.g., tall oil, palm oil,
cottonseed oil, linseed oil, soybean oil, peanut
oil, castor oil and lanolin. These listings are
merely illustrative. Any oil having the required
physical properties can be used.
The amount of oil in a particular
formulation is dependent upon a number of empirical
characteristics of the ingredients in that
ormulation. The oil is present in an amount
relative to the amount of water such that the oil
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forms the continuous phase in the final
formulation. Usually the oil should be present in
an amount by weight that exceeds the amount of
water. As a general rule, weight percentages of
~rom about twenty to about sixty percent of oil are
us~ful.
In general, the water should not exceed
twenty percent by weight, although in some
instances, higher values can be useful. For
example, in a composition containing a small amount
(about 10%) growth regulator and a high amount of
surfactant ~about 30%) and a substantial amount of
oil (about 35%), approximately 25% by weight water
is re~uired. Usually, however, the amount of water
will seldom exceed 15% by weight of the final
formulation.
As with the oil, the hydrophobic surfactant
must be chemically stable at the low pH conditions
produced by the phosphonic acid plant growth
regulator compound, especially the very low pH
conditions produced by the preferred concentrated
a~ueous ~olutions of phosphonic acid plant growth
regulators. Further, the surfactant mu~t not raise
the pH to a level that would lead to decomposition
of the active compound. As a general rule any
hydrophobic anionic, cationic or nonionic
surfactant that does not raise the system pH can be
used. Formulations using anionic or nonionic
surfactants appear to offer better long term
stability.
Care must be taken in selecting the
surfactant since some ester-containing sur~actants
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may undergo slow hydrolysis, leading to gradual
deterioration of the formulation if it is ~tored at
elevatea temperatures for extended periods of time.
Further, many cationic surfactants contain
nitrogenous functional groups, which, over a period
of time, may lead to decomposition of the preferred
phosphonic acid compounds.
The extent of interaction between wa~er,
oil and surfactant can be predicted from the
hydrophilic-lipophilic balance (HLB) of the
surfactant. The HLB values for most surfactants are
reported on a ccale of 0-20 in which values of 0 to
6 indicate strony hydrophobicity (or lipophilicity),
6 to 10 moderate hydrophobicity, 10 to 14 moderate
hydrophilicity (or lipophobicity) and 14 to 20
strong hydrophilicity.
The requirement that the surfactant be
hydrophobic arises because of the nature of the oils
tha~ are most useful in the compositions of this
invention. The substituted and unsubstituted
aliphatic and aromatic hydrocarbons and the extracts
from natural sources are non-polar or only slightly
polar materials. As a general rule preparation of
water-in-oil dispersions of these kinds of liquids
requires a hydrophilic surfactant of high HLB, i.e.,
approximately 1~-17. It was discovered, however,
that in the presence of ten to fifty percent
2-haloethyl phosphonic acid, such surfactants fail
to produce stable microemulsions. The difficulty
can be overcome if a hydrophobic surfactant, i.e., a
surfactant of HLB less than about 8, is used.
Without intending to be bound by any kheory
proposed, it is thought that the tendency of the
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phosphonic acids in water to hydrogen bond with the
~urfactant accounts for this surprising
observation. As $he acid interacts with the water
and the surfactant, the resulting aggregate of
surfactant and acid apparently has an effective HLB
value of 13 or more. When a surfactant with a high
HLB value is utilized ei~her alone, or as the major
component in combinations of surfactants, the
effective HLB is raised to such a high value that no
microemulsion forms at all, or one is formed but its
thermodynamic stability is short-lived. Whatever
the mechanism of surfactant-acid interaction may be,
it is clear that the preparation and stability of
emulsions of 2-haloethyl phosphonic acid require the
use of hydrophobic surfactants when the oil of
choice has the properties of those listed above.
Representative of the surfactants that can
be used in the compositions of this invention are
mono-subs~ituted glycerol derivatives of fatty acids
containing from about tPn to about thirty carbon
atoms, e.g., monostearates, monooleates and
monolaurates; sugar-based fatty acid derivatives
containing from about ten to about thirty carbon
atoms in the fatty acid chain; acetylated glycerides
of natural oils (i.e., liquids extracted from
natural sources); and polyethoxylated alcohols or
alkylphenols with branched or straight chain alkyl
groups containing from about six to about thirty
carbon atoms. Ester, phosphate ester and phosphate
acid analogues of many of these agents may also be
u~eful. Stable hydrophobic amine or amide
derivatives rnay also prove effective.
D-14,046
13 ,~ 7
The esp~cially preferred surfactants are
the anionic or nonionic polyethoxylated derivatives
of alcohol6 and phenol~ containing from about eight
to about thirty carbon atoms and less than twenty
moles of ethylene oxide per mole of alcohol or
phenol.
To achieve maximum dispersion and
stability, tha compositions of this invention
require the use of substantial amounts of
surfactant. While the optimum amount must be
determined empirically according to the amount of
growth regulator and the nature and amount of the
oil to be used, weight percentages ranging from
about ten to about forty percent are typical.
One very unexpected property of some of the
microemulsions of this invention is their toleration
of changes in the formulation HLB. Formation of a
~table dispersion usually requires a delica~e
balancing of oil, water and surfactant. This is
particularly true for microemulsions. For example,
if a highly polar liquid or a very hydrophilic
surfactant (i.e., one having an HLB value of 17 or
more) were added to a stable microemulsion of
non-polar oil, water and surfactant, the dispersion
would separate into phases, ~ither immediately or
after standing, because the thermodynamic balance
had been destroyed. However, microemulsions
~ontaining 2-haloethyl phosphonic acid and a
hydrophobic curfactant tolerate the addition of
significant quantities of very hydrophilic anionic
or nonionic ~urfactant without losing their
thermodynamic stability. An emulsion containing as
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- - 14 - ~ 9~
little a~ ~en ~o fifteen percent by weight
hydrophobic surfactant will remain stable if as much
aæ nine percent by weight very hydrophilic
surfactant is added. This ch~racteristic is of
practical advantage in tha~ apparatus ~sed to apply
the emul~ion can be cleaned simply with water.
In the absence of the hydrophilic
; surfactant, emulsion residues resist water because
the surfactant is 80 hydrophobic ~hat when rinse
water is introduced into the apparatus, the emulsion
re~idue coalesces and the water-immiscible li~uid
adhere~ to the walls of the apparatus.
Incorporation of hydrophilic surfactant into the
emulsion permits the emulsion residue to mix with
the water and be washed away.
To prepare the compositions of tbis
invention, the components can be added in any order
but must be mixed together with sufficient vigor
un~il the microemulsion forms, usually at ambient
temperatures. Occasionally slight heating up to
about 50C may be required. If, however, the proper
amounts of growth regulator, oil, water or
surfactant are unknown, or if the particular
ingredients interact so that no microemulsion forms
after mixing, a co-surfactant may be added.
A "co-surfactant" is a low molecular weight
non-ionizing organic compound which contains a polar
functional group and which enhances the interaction
of surfactant, water and oil. The co-surfactant can
be incorporated into the mixture at any time during
the preparation. If, however, the proportions of
oil to water in a particular formulation must be
D-14,046
- 15 - ~2 ~Z ~
very delicately balanced, addition of the
co-surfactant should be done after the growth
regulator, water, surfactant and oil have been ~ixed
into a macroemulsion. The macroemuls~on ~hould then
be vigorously mixed while co-surfactant is titrated
into it. Titration continues until the opaque
macroemulsion becomes transparent or translucent.
Should the macroemulsion be colored, then some
indication for conversion of macroemulsion to
microemulsion ehould be monitored; for example,
there might be a color change or disappearance of
cloudines~.
Traditional co-surfactants are straight
chain aliphatic alcohol6 containing from one to
about six carbon atoms. For purposes of this
inv~ntion branched or straight chain Cl-C15 mono
or polyhydroxy alcohols are suitable; formulations
containing t-butanol, C8-C10 linear alcohols,
ethylene glycol or propylene glycol have given
especially stable microemulsions. Urea and
substituted ureas containing up to four Cl-C3
alkyl substituents, and dialkylformamides containing
Cl-C3 alkyl groups are useful; urea and
dimethylformamide have proved particularly
beneficial. Trialkylphosphates containing Cl-C~
straight or branched alkyl groups can be used:
tributylphosphate is an effective co-surfactant.
As with the other ingredients, the amount
of co-surfactant for a particular formulation must
be determined empirically. However, typical
concentrations range from about five to about thirty
percent. When a co-surfactant is used, the amount
of surfactant required in a formulation is generally
D-14,046
16 ~ ~ '7
reduced by about five to ten percent relative to
formulations with no co-surfactant.
The toleration of the microemulsion to changes in
system HLB is generally not destroyed by the use of a co-
surfactant. We have discovered, however, that surfactants
with slightly higher HLB values, approximately eight to
nine, can be used if the formulation contains a co~
surfactant.
The following examples are set forth for purposes of
illustration.
A. Formulations without Co-Surfactant
Example 1
A microemulsion was prepared by combining 3.6 g 70%
aqueous 2-chloroethyl phosphonic acid, 3.6 g mixture of
aromatic hydrocarbons (Aromatic 150*, Exxon), and 2 g
nonionic ethoxylated linear alcohol surfactant (Alfonic*
1412-40, Conoco) and blending until a transparent liquid
formed. The microemulsion was stable, chemically and
thermodynamically, up to 50C.
Example 2
A microemulsion was prepared by combining 3 g
mixture of isoparaffinic hydrocarbons (Isopar M*, Exxon),
3.5 ~ nonionic ethoxylated linear alcohol surfactant
(Alfonic* 1412-40, Conoco) and 3.5 g 70% aqueous 2-
chloroethyl phosphonic acid and blending until a transparent
liquid formed. The microemulsion was stable, chemically and
thermodynamically, up to 50C.
Example 3
A microemulsion was prepared by combining 3 g
mixture of aromatic hydrocarbons (HAN*, Exxon), 3 g nonionic
ethoxylated linear alcohol surfactant (Alfonic* 1412-40
* tr~dr marks
rn/
,
2gtr '7
17
conoco) and 2 g 70% aqueous 2-chloroethyl phosphonic acid
and blending until a transparent liquid formed. The
microemulsion was stable, chemically and thermodynamically,
up to 50C.
Example 4
A microemulsion was prepared by combining 5.3 g
mixture of isoparaffinic hydrocarbons (Isopar M*, Exxon),
2.8 g nonionic ethoxylated linear alcohol surfactant
(Alfonic* 1412-40, Conoco) and 1.9 g 70% aqueous 2-
chloroethyl phosphonic acid and blending until a transparent
liquid formed. The microemulsion was stable, chemically and
thermodynamically, up to 50C.
B. Formulations with Co-Surfactant
Example 5
A microemulsion was prepared ~y adding to 30 g tall
oil (L5 grade, Westvaco*), 10 g free acid of a complex
organic phosphate ester anionic surfactant ~Gafac RM-510*,
GAF) and 10 g linear Cg~C11 alcohol mixture (Neodol 91*,
Shell), mixing until dissolution was complete, stirring in
30 g 70% aqueous 2-chloroethyl phosphonic acid and adding
this macroemulsion to an equal volume of water. The
microemulsion showed poor stability, separating into two
phases after several hours.
Example 6
A microemulsion was prepared by combining 0.7 g
urea, 4 g 70% aqueous solution of 2-chloroethyl phosphonic
acid, 1 g organic phosphate ester anionic surfactant (Emphos
CS-341*, Witco) and 4 g tall oil (L5 grade, Westvaco*) and
shaking until a clear l:iquid formed. The microemulsion was
stable, chemically and thermodynamically, from -20C to
50C.
* tr~de m~rks
rn/
18
Example 7
A microemulsion was prepared by combining 4 g tall
oil (L5 grade, WestYaCo*) ~ 1 g organic phosphate ester
anionic surfactant (Emphos CS-341*, Witco), 0.5 g
ethoxylated nonylphenol nonionic surfactant (Tergitol NP-6*,
Union Carbide), 1.2 g propylene gylcol and 4 g 70% aqueous
2-chloroethyl phosphonic acid and stirring until a clear
liquid formed. The microemulsion was stable, chemically and
thermodynamically, up to 50C.
Example 8
A microemulsion was prepared by combining 5 g oleic
acid, 2 y free acid of complex organic phosphate anionic
surfactant (Gafac PE-510*, GAF), 1 g urea and 5 g 70%
aqueous 2-chloroethyl phosphonic acid and mixing until a
clear liquid formed. The microemulsion was stable,
chemically and thermodynamically, up to 50C.
Example 9
~ microemulsion was prepared by combining 4 g tall
oil (L5 special grade*, Westvaco), 1 g organic phosphate
ester anionic surfactant (Emphos CS-341*, Witco), 1 g
tributylphosphate and 6 g 70% aqueous 2-chloroethyl
phosphonic acid and mixing until a transparent liquid
formed. The microemulsion was stable, chemically and
thermodynamically, up to 50C.
* trade marks
rn/~c
Example 10
A microemulsion was prepared by combining
4 g tall oil ~L5A ~pecial grade, Westvaco~, 1 g
organic phosphate ester anionic surfactant (Emphos
CS-341, Witco), 1 g t-butanol and 6 g 70% a~ueous
2-chloroethyl phosphonic acid and mixing until a
transparent liquid formed. The microemulsion was
stable, chemically and thermodynamically, up to 50~C.
C. Formulations with Added HydroPhilic Surfactant
Exam~le 11
A microemulæion was prepared by combining
4.5 g mixture of aromatic hydrocarbons (Aromatic
150, Exxon), 1.1 g ree acid of complex organic
pho~phate ester anionic (hydrophobic) surfactant
(Ga ac RM-410, GAF), 0.8 g polyethoxylated
norlylphe.1oi ~nydLophilic) sur~tant (Arnox 95~,
Arjay) and 2.5 g 70% aqueous 2-chloroethyl
phosphonic acid and mixing until a transparent
liquid formed. The microemulsion was stable,
chemically and thermodynamically, up to 50C.
Residues rPmaining in storage or application
apparatus were easily washed away with a water rinse.
ExamPle 12
A microemulsion was prepared by combining
2.5 g tridecyloxypoly (ethyleneoxy) ethanol nonionic
(hydrophobic) surfactant (Emulphogene BC-420, GAF),
1.8 g nonylphenoxypoly (ethyleneoxy) ethanol
nonionic (hydrophilic) surfactant (Igepal C0-997,
GAF), 0.5 g ethylene glycol, 3.4 g mixture of
isoparaffinic hydrocarbons (Isopar M, Exxon) and
1.8 g 70% aqueous 2-chloroethyl phosphonic acid and
mixing until a transparent liquid formed. The
D-14,046
- 20 ~
microemul~ion was stable, chemically and
thermodynamically, up to 50C. Residues remain~ng
in ~torage or application apparatus were easily
washed away with a water rinse.
Exam~le 13
A microemulsion was prepared by combining
2.5 g nonionic ethoxylated linear alcohol surfactant
(Alfonic 1412-40, Conoco), 1 g methyl i~oamyl
ketone, 3 g 70% aqueous solution of 2-chloroethyl
phosphonic acid and 3 g mixture of isoparaffinic
hydrocarbons (Isopar M, Exxon) and mixing until a
tran6parent li~uid formed. The microemulsion was
stable chemically and thermodynamically, up to
50C. ~esidues remaining in storage or application
apparatus were easily washed away with a water rinse.
Example 14
A microemulsion was prepared by combining
2.5 g tridecyloxypoly (ethyleneoxy) ethanol nonionic
(hydrophobic) ~urfactant (Emulphogene BC-420, GAF),
1.5 g nonylphenoxypoly (ethyleneoxy) ethanol
nonionic (hydrophilic) surfactant (Igepal C0-997,
GAF) 0.5 g methyl isoamyl ketone, 2.5 g mixtur~ of
isoparaffinic hydrocarbons (Isopar ~, Exxon) and 3 g
70% aqueous solution of 2-chloroethyl phosphonic
acid and mixing until a transparent liquid formed.
The microemulsion was stable, chemically and
thermodynamically up to 50C. Residues were easily
washed from ~torage and application equipment with a
water rinse.
The compositions of this invention can be
applied with ULV equipment in neat form or after
dilution with an oil extracted from a natural
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source; cottonseed or ~oybean oil are very commonly
used for this purpose. The decision to dilute will
depend upon the concentration o~ active in the
microemulsion, the ease of applying the formulation
in neat form and the concPntration of active needed
to induce ~he desired response in the plant.
Coverages ranging from about 0.1 to as high as about
30 lbs a.i.~A have been used, although the emulsions
are customarily applied at rates ranging from 0.5 to
2 lb a.i./A.
The following examples are given to
illustrate the utility of these compositions in
regulating growth in cotton plants. In these
examples To is the day of application, Tl is
observation seven days later, and T2 is
observation four~een days later.
EXAMPLE A
The formulation of example 2 was applied
with ULV equipment by airplane under a clear sky
with no wind at a temperature of 82F to twenty rows
of a field planted four and one half months earlier
with Stoneville 825 cotton. Coverage of
2 chloroethyl phosphonic acid was l lb. a.i./A.
Interior parts of the treated plot were monitored
for % boll opening, density of green bolls and %
defoliation over a two week period. Observations
were compared to those obtained for six untreated
row~ and to a field on which an aqueous ~olution of
2-chloroethyl phosphonic acid was applied at l lb.
a.i./A by conventional ~pray equipment. Results are
summarized in Table I.
D-14,0~6
- 22 ~
EX~MPLE B
The formulation of example 4 was applied
with ULV equipment ~y airplane under a clear sky
with no wind at a temperature of B2F to twenty rows
of a field planted four and one half months earlier
with Stoneville 825 cotton. Coverage of
2-chloroethyl phosphonic acid was 0.5 lb. a.i./~.
Interior parts of the treated plot were monitored
for ~ boll opening, density of green bolls and %
defoliation over a two week period. Observations
were compared to those obtained for six untreated
rows and to a field Ol1 which an aqueous solution of
2-chloroethyl pho~phonic acid was applied at 1 lb
a.i./A by conventional spray equipment. Results are
summarized in Table I.
TABLE I
Boll No. Green Bolls/ Defoliation
Opening (%) 10 ft. row (%)
Example To Tl T2 To Tl T2 To Tl T2
A 72 98 100 39 3 0 40 99 98
Aq. ref. *A 52 70 99 75 33 5 31 83 90
B 60 97 100 45 3 1 55 96 96
Aq. ref. *B 69 73 96 48 22 5 31 83 89
UTC~ 65 -- 75 -~ - -- -- 35**~
* Aq. ref. = aqueous reference solution
applied at the same coverage as the
relevant example
** UTC = untreated controls
*~* some regrowth was observed
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^ .:
- 23 -
When aqueous ~olutions o~ 2-c~loroe~hyl
phosphonic acid are applied to cotton fields under
~imilar conditions at identical coverages, the
effects on boll opening, ormation and defoliation
are comparable, to, and perhaps slightly poorer
than, those reported above with the microemulsions
of Examples 2 and 4. It is clear that the
compositions of this invention are at least equally
effective as known agueous growth regulator
formulations. They offer the added advantage of
being applicable with the modern ULV equipment.
The result~ of Examples A and B are shown
on Table I. Note that the microemulsion of Examples
2 and 4 produced enhanced results when compared with
aqueous solution applied at the same rate. The
microemulsion compositions of the invention
ou~performed the aqueous sGlutions based on
observations two weeks after application. Moreover,
the inventive formulations induced comparable if not
better results in just seven days than the aqueous
solutions produced after fourteen days.
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