CA1282977C - Plant growth regulator dispersions - Google Patents
Plant growth regulator dispersionsInfo
- Publication number
- CA1282977C CA1282977C CA000525892A CA525892A CA1282977C CA 1282977 C CA1282977 C CA 1282977C CA 000525892 A CA000525892 A CA 000525892A CA 525892 A CA525892 A CA 525892A CA 1282977 C CA1282977 C CA 1282977C
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-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
- A01N25/02—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing liquids as carriers, diluents or solvents
- A01N25/04—Dispersions, emulsions, suspoemulsions, suspension concentrates or gels
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N57/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds
- A01N57/18—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-carbon bonds
- A01N57/20—Biocides, pest repellants or attractants, or plant growth regulators containing organic phosphorus compounds having phosphorus-to-carbon bonds containing acyclic or cycloaliphatic radicals
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Plant Pathology (AREA)
- Engineering & Computer Science (AREA)
- Dentistry (AREA)
- Pest Control & Pesticides (AREA)
- Agronomy & Crop Science (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (AREA)
- Toxicology (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Cultivation Of Plants (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Formulations containing aqueous phosphonic acid plant growth regulator dispersed in oil are disclosed that are stable and particularly suited for use with ultra-low volume spray apparatus.
Formulations containing aqueous phosphonic acid plant growth regulator dispersed in oil are disclosed that are stable and particularly suited for use with ultra-low volume spray apparatus.
Description
~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
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.
D-14,046 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 D-14,046 - 4 - ~2~ 7 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 D-14,046 (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.
D-14,046 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 D-14,046 - 4 - ~2~ 7 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 D-14,046 (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 D-14,046 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.
D-14,046 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 D-14,046 - lo- ~2BZ977 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 D-14,046 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 D-14,046 - 12 ~ r~
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 D-14,046 - - 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 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/
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
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 D-14,046 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.
D-14,046 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 D-14,046 - lo- ~2BZ977 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 D-14,046 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 D-14,046 - 12 ~ r~
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 D-14,046 - - 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 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/
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 D-14,046 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 Aq. ref. *A 52 70 99 75 33 5 31 83 90 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 D-14,046 ^ .:
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.
D-14,046
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 D-14,046 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 Aq. ref. *A 52 70 99 75 33 5 31 83 90 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 D-14,046 ^ .:
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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Claims (14)
1. A stable plant growth regulating composition which comprises a dispersion, having a Brookfield viscosity of less than 800 cps and containing micelles no larger than 300 nm, of:
a. from about ten percent (10%) to about fifty percent (50%) by weight of a phosphonic acid plant growth regulator compound; and b. from about twenty percent (20%) to about sixty percent (60%) by weight of liquid which is:
i. substantially immiscible with water;
ii. not a solvent for said regulator compound; and iii. stable at the pH of said regulator compound; and 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 of hydrophobic surfactant or surfactant mixture which is stable at pH of said regulator compound.
a. from about ten percent (10%) to about fifty percent (50%) by weight of a phosphonic acid plant growth regulator compound; and b. from about twenty percent (20%) to about sixty percent (60%) by weight of liquid which is:
i. substantially immiscible with water;
ii. not a solvent for said regulator compound; and iii. stable at the pH of said regulator compound; and 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 of hydrophobic surfactant or surfactant mixture which is stable at pH of said regulator compound.
2. A composition according to claim 1 wherein said phosphonic acid plant growth regulator compound is 2-chloroethyl phosphonic acid.
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D-14,046
3. A composition according to claim 1 wherein said Brookfield viscosity is less than 300 cps.
4. A composition according to claim 1 wherein said liquid is:
a. an aromatic hydrocarbon;
b. an organic extract derived from a natural source; or c. an aliphatic hydrocarbon containing up to thirty carbon atoms, up to four non-adjacent double bonds, and up to four halogen, carboxyl or hydroxyl substituents.
a. an aromatic hydrocarbon;
b. an organic extract derived from a natural source; or c. an aliphatic hydrocarbon containing up to thirty carbon atoms, up to four non-adjacent double bonds, and up to four halogen, carboxyl or hydroxyl substituents.
5. A composition according to claim 4 wherein said liquid is a paraffin, isoparaffin, benzene, alkylbenzene containing up to four C1 to C4 substituents, a fatty acid or triglyceride derivative containing from about twelve to about thirty carbon atoms, tall oil, palm oil, cottonseed oil, linseed oil, soybean oil, peanut oil, castor oil, lanolin or a mixture thereof.
6. A composition according to claim 1 wherein said surfactant is a mono-substituted glycerol derivative of a fatty acid containing from about ten to about thirty carbon atoms; a sugar-based fatty acid derivative containing from about ten to about thirty carbon atoms in the fatty acid chain; an acetylated glyceride of a natural oil; a polyethoxylated alcohol or alkylphenol with D-14,046 branched or straight chain alkyl groups containing from about six to about thirty carbon atoms; or an ester, a phosphate acid, a phosphate ester, an amine or an amide analogue thereof; or any mixture thereof.
7. A composition according to claim 6 wherein said surfactant is one or more anionic or nonionic polyethoxylated alcohol or phenol compounds containing from about eight to about twenty carbon atoms in the alkyl chain and less than twenty moles of ethylene oxide per mole of alcohol or phenol.
B. A composition according to claim 1 and from about five percent (5%) to about thirty percent (30%) by weight of co-surfactant.
9. A composition according to claim 8 wherein said co-surfactant is a branched or straight chain C1-C15 mono or polyhydroxy alcohol: urea ox substituted urea containing up to four C1-C3 alkyl substituents: a dialkylformamide containing C1-C3 alkyl groups or a trialkylphosphate containing C1-C6 straight or branched alkyl groups.
10. A composition according to claim 9 wherein said co-surfactant is t-butanol: a mixture of C8-C10 alcohols; dimethylformamide; ethylene glycol: propylene glycol; or tributyl phosphate.
11. A composition according to claim 1 which also includes up to ten percent (10%) by weight of hydrophilic surfactant of HLB value at least 16.
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12. A composition which comprises from about twenty percent (20%) to about thirty percent (30%) by weight 2-chloroethyl phosphonic acid, from about seven percent (7%) to about fourteen percent (14%) by weight water, from about thirty-five percent (35%) to about forty percent (40%) by weight mixture of aromatic hydrocarbons and from about twenty percent (20%) to about twenty-five percent (25%) by weight nonionic ethoxylated linear alcohol.
13. A composition which comprises from about tan percent (10%) to about twenty-five percent (25%) by weight 2-chloroethyl phosphonic acid, from about five percent (5%) to about ten percent (10%) by weight water, from about thirty percent (30%) to about thirty-five percent (35%) by weight mixture of isoparaffins and from about twenty-five percent (25%) to about thirty-five percent (35%) by weight nonionic ethoxylated linear alcohol.
14. A composition which comprises from about fifteen percent (15%) to about twenty-five percent (25%) by weight 2-chloroethyl phosphonic acid, from about seven percent (7%) to about ten percent (10%) by weight water, from about fifty percent (50%) to about fifty-five percent (55%) by weight mixture of aromatic hydrocarbons, from about ten percent (10%) to about fourteen percent (14%) by weight hydrophobic anionic free acid of complex organic phosphate ester and from about eight percent (8%) to about ten percent (10%) by weight hydrophilic polyethoxylated nonylphenol.
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Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US81489885A | 1985-12-30 | 1985-12-30 | |
| US814,898 | 1985-12-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1282977C true CA1282977C (en) | 1991-04-16 |
Family
ID=25216288
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000525892A Expired - Lifetime CA1282977C (en) | 1985-12-30 | 1986-12-19 | Plant growth regulator dispersions |
Country Status (9)
| Country | Link |
|---|---|
| CN (1) | CN86108939A (en) |
| AU (2) | AU6890287A (en) |
| BR (1) | BR8607066A (en) |
| CA (1) | CA1282977C (en) |
| EG (1) | EG17951A (en) |
| GB (1) | GB2194226B (en) |
| TR (1) | TR22763A (en) |
| WO (1) | WO1987004047A1 (en) |
| ZA (1) | ZA869743B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19834598A1 (en) * | 1998-07-31 | 2000-02-03 | Hoechst Schering Agrevo Gmbh | Aqueous suspension concentrate containing thidiazuron and ethephon |
| WO2000018235A1 (en) * | 1998-09-29 | 2000-04-06 | Aventis Cropscience S.A. | Method of sugarcane flower inhibition and new composition |
| DE10258867A1 (en) * | 2002-12-17 | 2004-07-08 | Bayer Cropscience Gmbh | Microemulsion concentrates |
| MX2012002483A (en) * | 2012-02-27 | 2013-08-27 | Inst De Ecologia A C | Use of a herbicidal composition for controlling parasitic plants. |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| PH9673A (en) * | 1970-11-02 | 1976-02-10 | J Esposito | Latex stimulant and method of use |
| GB1508495A (en) * | 1975-06-06 | 1978-04-26 | British Petroleum Co | Spraying method |
-
1986
- 1986-12-10 GB GB8719970A patent/GB2194226B/en not_active Expired - Fee Related
- 1986-12-10 AU AU68902/87A patent/AU6890287A/en not_active Abandoned
- 1986-12-10 BR BR8607066A patent/BR8607066A/en unknown
- 1986-12-10 WO PCT/US1986/002636 patent/WO1987004047A1/en unknown
- 1986-12-19 CA CA000525892A patent/CA1282977C/en not_active Expired - Lifetime
- 1986-12-29 CN CN198686108939A patent/CN86108939A/en active Pending
- 1986-12-29 ZA ZA869743A patent/ZA869743B/en unknown
- 1986-12-29 TR TR18/87A patent/TR22763A/en unknown
- 1986-12-30 EG EG805/86A patent/EG17951A/en active
-
1990
- 1990-12-24 AU AU68484/90A patent/AU6848490A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| BR8607066A (en) | 1988-02-23 |
| GB8719970D0 (en) | 1987-09-30 |
| AU6890287A (en) | 1987-07-28 |
| GB2194226B (en) | 1990-02-07 |
| ZA869743B (en) | 1987-08-26 |
| WO1987004047A1 (en) | 1987-07-16 |
| EG17951A (en) | 1991-08-30 |
| CN86108939A (en) | 1987-07-22 |
| GB2194226A (en) | 1988-03-02 |
| AU6848490A (en) | 1991-03-14 |
| TR22763A (en) | 1988-06-21 |
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