WO1999059406A1

WO1999059406A1 - Alkyl ether citrate, tartrate, or adipate surfactants and their use in agricultural formulations

Info

Publication number: WO1999059406A1
Application number: PCT/US1999/010857
Authority: WO
Inventors: George B. Beestman; Jerry M. Green
Original assignee: E.I. Du Pont De Nemours And Company
Priority date: 1998-05-18
Filing date: 1999-05-17
Publication date: 1999-11-25
Also published as: EP1077605A1; AU3998499A; CA2328479A1

Abstract

This invention pertains to the use of certain alkyl ether citrate, tartrate or adipate surfactants for enhancing biological activity of agricultural herbicides.

Description

TITLE

ALKYL ETHER CITRATE, TARTRATE, OR ADIPATE SURFACTANTS

AND THEIR USE IN AGRICULTURAL FORMULATIONS

FIELD OF THE INVENTION This invention pertains to herbicidal compositions having included therein surfactants that can enhance the biological activity of low dose herbicides and can be formulated in a dry form.

BACKGROUND OF THE INVENTION Herbicides are used to control unwanted plant vegetation and are widely recognized as essential components in the efficient production of food. It is desirable to keep the herbicide rates low to minimize cost and to minimize adverse environmental effects caused by off-target movements or residues left in the crop or soil.

During the past two decades, new classes of herbicides have been discovered and developed that provide useful weed control at application rates below 100 g a.i./hectare. Their low use rates help minimize environmental impact and waste generated in manufacturing as well as providing storage and handling convenience. These low dosage herbicides are known to function by inhibiting key plant biosynthetic enzymes such as acetolactate synthase, protoporphyrinogen oxidase and/7-hydroxyphenylpyruvate deoxygenase. When herbicides are applied to plant foliage, adjuvants can be useful in enabling low dose herbicides to perform consistently under variable conditions (Roberts, J. R. (1992): A review of the methodology employed in the laboratory evaluation of spray adjuvants pp. 503-512 Foy, C. L. (Ed.) Adjuvant for Agrichemicals, CRC Press, Boca Raton). These adjuvants can be included in the herbicide formulation or can be added to the spray mixture. Adjuvants that increase biological activity include certain crop oil concentrates, certain surfactants, and certain ammonium-based inorganic salts or fertilizer. The oil in the crop oil concentrate adjuvants can be vegetable oil, modified vegetable oil (usually esters or salts of fatty acids), or mineral (petroleum) oils. Adjuvants allow herbicides to be used at low rates and allow control of more species than if the herbicide was used alone. This effect is described by Green, J. M. and Green, J. H. (1993): Weed Technology 7:633-640.

Adjuvants are used at various dosages depending on adjuvant type and standard practices, which vary by geographical location. For example, use recommendations for crop oil concentrate adjuvants most commonly range from 0.5% to 1% of the spray volume. The 0.5% concentration is common in Europe and 1% is common in the U.S. with some label recommendations as high as 2%. When added directly to the spray tank, certain surfactants are used at 0.25% of the spray volume in the U.S. and as low as 0.1% in Europe. The surfactant and crop oil concentrate adjuvants currently in use are liquids or low melting solids that are incompatible with dry herbicide formulations and must be packaged separately. In the U.S., ammonium fertilizers are commonly used as adjuvants to enhance herbicide activity at concentrations of 2 to 4% of spray volume.

The above quantities of adjuvants are too large to formulate with low dosage herbicides because the concentration of the herbicide in the final product formulation would be diluted to unacceptably low levels. There is a need for adjuvants which enhance herbicide activity at lower doses than current commercial adjuvants and could therefore be formulated with the herbicide while maintaining the desirable features of low use rates.

U.S. Patent 5,273,953 describes certain citrate surfactants as useful in plant protection or veterinary formulations.

SUMMARY OF THE INVENTION This invention concerns a herbicidal composition comprising at least one low-dose herbicide; at least one surfactant selected from Formulae I, II and III including stereoisomers,

COOR³

I

O— C-H II

I

O-C-H

C I OOR 4⁴

wherein each of R, R², R³, R⁴, R⁵, R⁶ and R⁷ are independently selected from the group consisting of H, M or (CH₂CH₂O)_xCH2(CH2)_yCH3; R¹ is H or COOR⁷; provided that when R and R2 are other than (CH₂CH₂O)_xCH2(CH₂)_yCH3 then Rl is COOR⁷ and R⁷ is (CH₂CH₂O)_xCH₂(CH2)_yCH₃; that at least one of R³ and R⁴ is (CH₂CH₂O)_xCH2(CH2)_yCH₃; and that at least one of R⁵ and R⁶ is (CH₂CH₂O)_xCH2(CH₂)_yCH3; each R⁸ is independently H or OH; each M is independently an organic or inorganic cation; each x is independently an integer 4 to 50; each y is independently an integer 0 to 20; and optionally at least one additive selected from the group consisting of a surfactant, an oil, an ammonium salt, a drying agent, a dispersant, a wetting agent, an anti-caking agent, an anti-foaming agent, a chemical stabilizer, an inert diluent, and an adjuvant for enhancing biological activity; wherein the ratio of concentration of surfactant to herbicide ranges from about 1.5:1 to 150:1. This invention also concerns a method for controlling the growth of undesired vegetation which comprises adding the herbicidal composition described above to water and applying to the locus to be protected an effective amount of the herbicidal composition in water.

DETAILED DESCRIPTION OF THE INVENTION This invention pertains to the use of certain alkyl ether citrate, tartrate and adipate surfactants for enhancing biological activity of low-dose agricultural herbicides. A low-dose herbicide is defined in the context of this disclosure to be a herbicide that is efficacious for control of undesired vegetation at application rates of less than 100 g a.i./ha. The alkyl ether citrate, tartrate or adipate compounds of Formula I, II or III provide a high unit activity to these herbicides compared to the same agricultural herbicides applied alone. These surfactants surprisingly provide the enhanced biological effect at doses lower than is generally needed with common surfactants. Because the surfactants of Formula I, II or III are remarkably effective, they can be included in formulated compositions of low-dose herbicides in sufficient amount to enhance the biological effect without the grower or farmer needing to add additional adjuvants to the spray tank. Certain salts and certain highly ethoxylated forms of the surfactants of Formula I, II, or III are solids and therefore particularly useful in solid types of formulations.

Preferred is the composition wherein the low-dose herbicide is selected from acetolactate synthase inhibiting herbicides, protoporphyrinogen oxidase inhibiting herbicides, /7-hydroxyphenylpyruvate deoxygenase inhibiting herbicides, and combinations thereof. More preferred is the composition wherein the low-dose herbicide is an acetolactate synthase inhibiting herbicide. Most preferred is the composition wherein the acetolactate synthase-inhibiting herbicide is selected from the group consisting of thifensulfuron-methyl, rimsulfuron and nicosulfuron; and mixtures thereof. Preferred is a composition composed of herbicide granules and surfactant granules, the herbicide and optionally at least one additive comprising the herbicide granules; and at least one compound selected from Formula I, II and III, and optionally at least one additive comprising the surfactant granules.

Preferred is the composition wherein the surfactant is of Formula I. More preferred is the composition wherein the surfactant is of Formula la, lb or Ic: O

I !

CH2-C-0-H

I

HO-C-COOH

CH2-C-0-(CH2-CH2-0)_x-CH₂-(CH2)io-CH3

⁰ la wherein x is 4, 7, or 9;

O

CH₂-C-O(CH₂-CH₂-O)_X-CH₂-(CH₂)₁₀-CH₃ HO-C-COO-(CH₂-CH₂-O)_x-CH₂-(CH₂)ιo-CH₃ CH₂-C-O-(CH₂-CH₂-O)_x-CH₂-(CH₂)ιo-CH₃ O lb

wherein x is 4, 7, or 9;

O

II

CH -C-0^"M⁺

HO-C-CCO(CH2-CH2-0)_x-CH2-(CH2)_y-CH3

CH2-C-0-(CH2-CH₂-0)_x-CH₂-(CH₂)_y-CH3 O

Ic wherein x is 17, y is an integer 14 to 16, and M is K⁺, Na⁺ or NH,4⁺.

Especially preferred is the method wherein the concentration of the at least one surfactant and any adjuvant additive is about 0.01 to about 0.1% of the spray volume.

The mono-ethoxylated surfactants of Formula la, the tri-ethoxylated surfactants of Formula lb and the C^g alkyl citrate surfactants of Formula Ic are commercially available from Witco Corporation, Greenwich, CT. More generally, surfactants of Formulae I, II and III are prepared by condensing the corresponding free carboxylic acids with CH3(CH₂)_yO(CH₂CH2θ)_xH. The resulting average number of carboxylic acid groups per molecule esterified with CH3(CH2)_yO(CH2CH₂O)_xH depends upon the ratio of the number of moles of CH3(CH₂)_yO(CH CH₂O)_xH to the number of moles of the starting free carboxylic acid. For example, to esterify a single carboxylic acid group per molecule, the mole ratio of starting CH3(CH2)_yO(CH₂CH₂O)_xH to free carboxylic acid is about 1 :1. For esterification of additional carboxylic acid groups per molecule, the mole ratio of CH₃(CH2)_yO(CH2CH2θ)_xH to starting free carboxylic acid is correspondingly increased. The esterification condensation reaction is accelerated by heating and catalysis using strong protic acids, such as phosphoric acid, sulfuric acid, /?-toluenesulfonic acid and sulfonic acid resins, or Lewis acids such as boron trifluoride and butyltin hydroxide oxide hydrate. Surfactants of Formulae I, II and III can exist as stereoisomers. The various stereoisomers include enantiomers and diastereomers. One skilled in the art will appreciate that while surfactant properties of stereoisomers are generally similar, some variation is possible between diastereomers. Furthermore, physical properties important to formulations, such as melting points, typically differ somewhat between pure enantiomers and racemic mixtures. Racemic mixtures usually, but not always, have higher melting points and lower solubilities than the separated enantiomers. The skilled artisan knows how to separate, enrich, and/or to selectively prepare said stereoisomers. The surfactants of Formula I, II and III may be present in the compositions of this invention as a mixture of stereoisomers or as a single stereoisomer. Salts of Formulae I, II and III wherein at least one of R, R², R³, R⁴, R⁵, R⁶ or R⁷ is M are very useful surfactants for this invention, because they are often solids. Each M is independently an organic or inorganic cation. Organic cations include, for example, isopropylammonium, triethylammonium, tetra-n-butylammonium, benzyltrimethylammonium and trimethylsulfonium. Inorganic cations include, for example, lithium, sodium, potassium, calcium, magnesium, barium and ammonium. Sodium, potassium and ammonium are preferred cations for this invention because of their low cost and solid-promoting ability. Salts of Formulae I, II and III wherein at least one of R, R², R³, R⁴, R⁵, R⁶ or R⁷ is M can be prepared by reacting the corresponding acid forms of Formulae I, II and III with amines (e.g., treatment with triethylamine to give the triethylammonium salt) or with bases such as hydrides, hydroxides, alkoxides or carbonates of lithium, sodium, potassium, calcium, magnesium, barium or quaternary ammonium. Ammonium salts can be prepared by treatment with anhydrous ammonia or ammonia dissolved in water (i.e. ammonium hydroxide).

It will be recognized by one skilled in the art that the desired effect of enhancement of herbicide activity may be obtained by use of at least one of the citrate, tartrate, or adipate based surfactants of Formula I, II or III, by a combination thereof, or by a combination of said citrate, tartrate, or adipate based surfactants of Formula I, II or III with one or more other adjuvants known to enhance herbicidal activity.

Preferred low-dose herbicides of the present invention are selected from the group consisting of acetolactate synthase inhibiting herbicides, protoporphyrinogen oxidase inhibiting herbicides, -hydroxyphenylpyruvate deoxygenase inhibiting herbicides, and combinations thereof. Acetolactate synthase inhibiting herbicides include sulfonylureas (and derivatives such as sulfamoylureas), such as amidosulfuron, azimsulfuron, bensulfuron- methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron- methyl, ethoxysulfuron, fiupyrsulfuron methyl, flazasulfuron, halosulfuron-methyl, imazosulfuron, metsulfuron-methyl, nicosulfuron, oxasulfuron, primisulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, sulfosulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl and triflusulfuron-methyl; triazolopyrimidine sulfonanilides, such as cloransulam-methyl, florasulam, flumetsulam and metosulam; pyrimidinyloxybenzoates, such as pyrithiobac and pyriminobac-methyl; imidazolinones, such as imazamethabenz-methyl, imazamox, imazapyr, imazaquin and imazethapyr; and compounds of other structural classes, such as flucarbazone; and the agriculturally useful salts of any of the foregoing.

Examples of protoporphyrinogen oxidase inhibiting herbicides include include azafenidin, carfentrazone-ethyl, flumiclorac-pentyl, flumioxazin, fluthiacet-methyl, oxadiazon, oxadiargyl, pyraflufen-ethyl, sulfentrazone and (6S-cw)-l-chloro-N-[2-chloro- 4-fluoro-5-(6-fluorotetrahydro-l,3-dioxo-lH-pyrrolo[l,2-c]imidazol-2(3H)-yl)phenyl]- methanesulfonamide, and the agriculturally suitable salts of any of the foregoing.

Examples of ?-hydroxyphenylpyruvate deoxygenase inhibiting herbicides include sulcotrione, isoxaflutole, and 2-[4-(methylsulfonyl)-2-nitrobenzoyl]-l,3-cyclohexanedione (mesotrione), and the agriculturally suitable salts of any of the foregoing.

Some of the aforementioned low-dose herbicides inhibiting acetolactate synthase, protoporphyringen oxidase or^-hydroxyphenylpyruvate deoxygenase can be present in the compositions of the present invention in the form of their agriculturally suitable salts. When a basic function (e.g., amine) is present in the herbicide molecule, agriculturally suitable salts include acid-addition salts with inorganic or organic acids such as hydrobromic, hydrochloric, nitric, phosphoric, sulfuric, acetic, adipic, butyric, citric, fumaric, lactic, maleic, malonic, oxalic, proprionic, salicylic, tartaric, 4-toluenesulfonic or valeric acids. When an acidic function (e.g., carboxylic acid or enol) is present in the herbicide molecule, agriculturally suitable salts include those formed with amine bases (e.g., pyridine, ammonia or triethylamine) or metallic or quaternary ammonium bases (e.g., hydrides, hydroxides, alkoxides or carbonates of lithium, sodium, potassium, calcium, magnesium, barium or quaternary ammonium). Particularly useful salts include the lithium, sodium, potassium, triethylammonium, and quaternary ammonium salts such as tetra-Η-butylammonium and benzyltrimethylammonium.

Methods of preparation of chemical classes comprising acetolactate synthase inhibiting herbicides, protoporphrinogen inhibiting herbicides and ?-hydroxyphenylpyruvate deoxygenase inhibiting herbicides, including the specific herbicidal compounds named above, are well taught in the patent literature. Most of the named compounds are commercial products. The compound (6S-c i^,)-l-chloro-N-[2-chloro-4-fluoro-5-(6- fluorotetrahydro-l,3-dioxo-lH-pyrrolo[l,2-c]imidazol-2(3H)-yl)phenyl]methanesulfonamide can be prepared as described in PCT Publication No. WO 97/15576. The synthesis involves the reaction of (βR-trans)- 1 -chloro-N-[2-chloro-4-fluoro-5-(tetrahydro-6-hydroxy- 1 ,3-dioxo- lH-pyrrolo[l ,2-c]imidazol-2(3H)-yl)phenyl]methanesulfonamide with diethylaminosulfur trifluoride (DAST) in dichloromethane solution. The compound 2-[4-(methylsulfonyl)-2- nitrobenzoyl]-l,3-cyclohexanedione can be prepared as described in U.S. 5,006,158. The synthesis involves rearrangement of 3-oxo-l-cyclohexen-l-yl 4-(methylsulfonyl)-2- nitrobenzoate in the presence of acetone cyanohydrin and triethylamine in acetonitrile. Flucarbazone can be prepared as described in U.S. 5,534,486. The synthesis involves the reaction of 2-(trifluoromethoxy)benzenesulfonyl isocyanate with 2,4-dihydro-5-methoxy-4- methyl-3H-l,2,4-triazol-3-one. U.S. 5,550,244 describes an alternative coupling method.

The ratio of concentration of surfactants to herbicides ranges from about 1.5:1 to about 150:1 by weight. These ratios refer to the total weight of surfactants of Formulae I, II and III compared to the total weight of low-dose herbicide active ingredients. Preferred is a ratio of about 2: 1 to about 40: 1. More preferred is about 4: 1 to about 35:1. Even more preferred is about 5 : 1 to about 30:1. Most preferred is about 10:1.

The composition of the present invention can be used alone or in combination with other commercial herbicides. The composition of the present invention can also comprise one or more high-dose herbicide active ingredients in addition to the low-dose herbicide active ingredient or ingredients. A mixture with one or more of the following herbicides may be particularly useful for weed control: acifluorfen, anilofos, asulam, atrazine, bentazon, bromacil, bromoxynil, hydroxybenzonitrile, chloramben, chloroxuron, chlortoluron, cyanazine, dazomet, desmedipham, dicamba, dichlobenil, dichlorprop, diphenamid, dipropetryn, diuron, fenac, fenuron, fluometuron, fluridone, fomesafen, glyphosate acid or its corresponding salts especially the isopropylamine, sodium, potassium, ammonium and trimesium salts, hexazinone, ioxynil, isoproturon, isouron, isoxaben, karbutilate, lenacil, 4-chloro-2-methylphenoxyacetic acid (MCPA), MCPB, mefenacet, mefluidide, methabenzthiauron, methazole, metribuzin, monuron, naptalam, neburon, nitralin, norflurazon, oryzalin, perfluidone, phenmedipham, picloram, prometryn, pronamide, propanil, propazine, pyrazon, siduron, simazine, tebuthiuron, terbacil, terbuthylazine, terbutyrn, triclopyr, and 2,4-dichlorophenoxyacetic acid (2,4-D) and its derivatives.

The compositions of the present invention may include at least one additive, such as a drying agent, a dispersant, an anti-caking agent, an anti-foaming agent, a wetting agent, a chemical stabilizer, a diluent, and other types of adjuvants. One skilled in the art would understand the purpose and selection of these additives. Drying agents/dispersants may be water-soluble or water-insoluble. Water-soluble drying agents include but are not limited to sodium, calcium and ammonium salts of ligninsulfonates (optionally polyethoxylated); salts of maleic anhydride copolymers, salts of polyacrylic acids, salts of condensed phenolsulfonic acids, salts of the napthalene sulfonate-formaldehyde condensates, polyvinylpyrrolidone, polyvinylalcohol, polyethylene oxide, and co-polymers of these. Water-insoluble drying agents include but are not limited to clays, synthetic and diatomaceous silicas, calcium and magnesium silicates, titanium dioxide, and charcoal. Useful levels include up to about 70% by weight. Adjuvants include but are not limited to other surfactants, oil concentrates, alkyl sulfosuccinates, taurates, alkyl sulfate and phosphate esters, acetylenic diols, ethoxyfluorinated alcohols, ethoxylated silicones and alkyl phenol ethoxylates, as well as organic sulfonates and alcohol ethoxylates. If an adjuvant is used, useful levels include up to about 10%) by weight. Anticaking agents to prevent clumping of granules stored under hot warehouse conditions include but are not limited to sodium and ammonium phosphates, sodium acetate, sodium metasilicate, magnesium, zinc and calcium sulfates, magnesium hydroxide, (all optionally as hydrates), anhydrous calcium chloride, molecular sieves, sodium alkylsulfosuccinates, calcium and barium oxides. If anticaking agent is needed, useful levels include up to about 10% by weight.

Chemical stabilizers to prevent decomposition of active ingredient during storage include but are not limited to sulfates of alkaline earths and transition metals such as magnesium, zinc, aluminum and iron; lithium, sodium and potassium phosphates; calcium chloride and oxide; and, boric anhydride. If chemical stabilizer is needed, useful levels include up to about 10% by weight.

Diluents may be water-soluble or water-insoluble. The water-soluble diluents may be salts, surfactants or carbohydrates which dissolve rapidly in water; non-limiting examples include sulfates of sodium, potassium, magnesium and zinc, sodium and potassium chloride, gelatin, urea, sugar, sorbitol, sodium benzoate, lactose, and alkali metal and alkali earth phosphates. Water-insoluble diluents include but are not limited to starch, modified starch, cyclodextrin, aluminum, calcium and zinc oxide, calcium and magnesium carbonate, sodium, potassium, calcium and barium sulfate. Water-soluble diluents are preferred. If diluent is needed, levels up to about 40%) by weight may be included.

Anti-foaming agents include but are not limited to stearates, silicones, and ethoxylates of HLB (Hydrophobic/Lipophilic Balance) values less than about 5.

The formulations are dry formulations including dusts, powders, granules, pellets, tablets, films, and the like which can be water-dispersible ("wettable") or water-soluble. Most preferred are granule or pellet type formulations. Conventional granulation methods for preparing granule compositions involve (1) water-spraying in fluidized bed or pan granulation equipment, (2) spray-drying, (3) extrusion of a water- wet paste, and (4) dry compaction or (5) melt extrusion.

The surfactant, herbicide and optionally at least one additive can be granulated together to provide granules comprising both the herbicide and the surfactant. Alternatively, the surfactant can be separately granulated prior to combination with the herbicide. In this latter embodiment, which is preferred, the at least one surfactant of Formula I, II or III and optionally at least one additive, as described above, can be granulated to form a surfactant granule, and the herbicide and optionally at least one additive, as described above, can be granulated to form a herbicide granule. The surfactant granules and the herbicide granules can then be combined and applied and/or packaged together, or packaged and/or applied separately.

The present invention further concerns a method for controlling the growth of undesired vegetation which comprises adding the herbicidal composition described above to water and applying to the locus to be protected an effective amount of the herbicidal composition which is soluble or dispersible in the water. Preferably the amount of surfactant and any adjuvant additive in the water is about 0.01 to about 0.1% weight or volume per volume of water. Application of the herbicidal composition can be by spraying. In spraying applications, the amount of surfactant and any adjuvant additive would preferably be about 0.01 to about 0.1% of the spray volume expressed either on a weight or volume basis.

Typical spray volumes range from as low as about 10 L/ha in aerial application up to about 500 L/ha in ground application.

The examples in the following Index Table, where R, R¹ and R² pertain to Formula I, illustrate specific embodiments within the broader scope of the invention.

REFERENCE EXAMPLE 1 Preparation of a surfactant corresponding to Formula II wherein R³ and R⁴ are both

(CH₂CH₂O)₁oCH₂(CH₂)₁₀CH₃

This Reference Example illustrates a general method for preparing surfactants useful for this invention.

A 1 L round bottom flask was charged with CH₃(CH₂)₁₀CH₂(OCH₂CH₂)₁₀OH ("Dehydol LS 9.5"; 103.55 g, 0.1652 mol), tartaric acid (12.4 g, 0.0826 mol), butyltin hydroxide oxide hydrate («-BuSn(O)OH ^■ H₂O, 3.0 g, 0.0144 mol, 17 mol % based on tartaric acid), and toluene (-250 mL ). The flask was fitted with a Dean-Stark trap and reflux condenser, and heated to 150 C under N₂ for 10 days. During this time the progress of the reaction was monitored by ¹³C{!H} NMR in (methyl sulfoxide)-^ solution according to the ¹³C chemical shifts: δ 173.08 (tartaric acid), 172.72 and 171.5 (ester-acid intermediate), and 171.2 (bis ester). After the reaction was complete, the mixture was allowed to cool to ambient temperature, diluted with additional toluene (~300 mL), and filtered through alumina (basic, Brockman I, -100 g) to remove the catalyst. The bulk of the toluene was removed using a rotary evaporator, and the remaining volatile compounds were removed in vacuo to leave the title surfactant.

EXAMPLE 1 The effect of Compounds 1-7 on the activity of nicosulfuron was investigated by tank mixing the compounds with the herbicide and compared with the activity of three commercial surfactants at the same rates. Evaluation of the compounds in Table 1 was made by mixing the compound with a nicosulfuron solution and spraying the resulting solution at a rate of 3.5 g /ha nicosulfuron in a spray volume of 187 L/ha on giant foxtail (Setariafaberi). Adjuvant dose is expressed on a weight basis as a % concentration of the spray volume. Four replications were made of each treatment. Plants were evaluated after two weeks by measuring their green fresh weights and converting these weight by comparison to an untreated control treatment into percent control values.

TABLE 1

Compound Cone. Control

No. % %

Herbicide Alone 0 12

1 0.04 70

0.1 85

2 0.04 92

0.1 97

3 0.04 91

0.1 97

4 0.04 78

0.1 88

5 0.04 96

0.1 98

6 0.04 95

0.1 98

7 0.04 74

0.1 93

Trend® 90 NIS 0.1 77

Agridex® COC 0.5 91

Scoil® MVO 0.5 98

Trend® 90 surfactant is 90% nonionic surfactant (isodecyl alcohol ethoxylate) sold by Du Pont de Nemours (France) S. A., 137 rue de l'Universite, 75334 Paris, France. Agridex® nonionic spray adjuvant is a crop oil concentrate (83%> paraffin base petroleum oil and 17%) surfactant emulsifiers) sold by Helena Chemicals Co., 5100 Poplar Ave., Memphis, TN 38137. Scoil® is a modified vegetable oil concentrate (mixture of methylated seed oil and surfactant emulsifiers) sold by Agsco, Inc., Mill Road, Grand Forks, ND 58206.

EXAMPLE 2 The effect of Compounds 1-7 on the activity of nicosulfuron was investigated by tank mixing the compounds with the herbicide and compared with the activity of two commercial surfactants at the same rates. Evaluation of the compounds in Table 2 was made by mixing the compound with a nicosulfuron solution and spraying the resulting solution at a rate of 3.5 g/ha nicosulfuron in a spray volume of 187 L/ha on giant foxtail (Setariafaberi). Six replications were made of each treatment. Plants were evaluated after two weeks by measuring their green fresh weights and converting these weight by comparison to an untreated control treatment into percent control values.

TABLE 2

Compound Cone. Control

No. % %

Herbicide Alone 0 2

1 0.04 61

0.1 73

2 0.04 85

0.1 93

3 0.04 89

0.1 94

4 0.04 80

0.1 93

5 0.04 91

0.1 97

6 0.04 95

0.1 98

7 0.04 61

0.1 91

8 0.04 93

0.1 97

9 0.04 74

0.1 86

Trend® 90 NIS 0.1 67

Scoil® MVO 0.5 98

EXAMPLE 3 A dry high concentration water-soluble granule formulation was prepared based upon a water-soluble drying agent/dispersant. These granules can subsequently be blended with herbicide dispersible granule formulations to produce herbicide/surfactant blends in all desired proportions.

Reax® 85A (sodium lignin sulfonate produced by Westvaco) 50%

Compound 6 50%

The lignosulfonate and alkylether citrate surfactant were dissolved in water and then dried in a vacuum oven. Resultant cake was milled to a powder, moistened, extruded, dried and broken to desired granule length. One skilled in the art would recognize that on a large scale it may be more advantageous to spray dry the aqueous solution to obtain dry powder directly. Other water soluble polymers such as acrylic-based, naphthalene-based, and pyrrolidone-based polymers may be used as drying agents or carriers for these alkylether citrates.

EXAMPLE 4 A dry high concentration water-dispersible granule formulation can be prepared based upon a water-insoluble drying agent. These granules can subsequently be blended with herbicide water-dispersible granule formulations to produce herbicide/surfactant blends in all desired proportions.

Compound 6 50%

Sipernat® 50S (a synthetic silica manufactured by Degussa Corp) 25%)

Aerosol® OTB (dioctylsulfosuccinate wetting agent manufactured 5%> by Cytec Industries, Inc.)

Foamaster® Soap L (tallowate anti-foam made by Henkel Corp.) 2%

Morwet® D425 (condensed naphthalene sulfonate dispersant 5% manufactured by Witco Corp.)

1 OX Powdered Sugar (diluent manufactured by Imperial Sugar 13%

Company)

Silica and citrate surfactant are combined by high shear mixing to form a powder. Other components are added, blended and milled to finer than 150 microns. The milled powder is moistened to an extrudable paste, extruded, dried, and broken to desired length granules.

EXAMPLE 5 A dry salt form of an acid citrate surfactant can be prepared that can be processed to granules without a drying agent. These granules can subsequently be blended with herbicide dispersible granule formulations to produce herbicide/surfactant blends in all desired proportions.

Compound 7 100%

The salt is milled to less than 150 microns, moistened to an extrudable past, extruded, dried, and broken to desired granule length. EXAMPLE 6

Example 3 was repeated using Compound 1 in place of Compound 6.

EXAMPLE 7 Example 3 was repeated using Compound 3 in place of Compound 6.

EXAMPLE 8 Example 3 was repeated using Compound 4 in place of Compound 6. EXAMPLE 9 Example 4 was repeated using Compound 1 in place of Compound 6.

EXAMPLE 10 Example 4 was repeated using Compound 3 in place of Compound 6. EXAMPLE 11

Example 4 was repeated using Compound 4 in place of Compound 6.

EXAMPLE 12 This is an example of a wettable powder formulation of a surfactant that can subsequently be used to formulate a herbicide product.

Compound 6 50%

Siperonat® 50S (a synthetic silica manufactured by Degussa) 25%>

Aerosol® OTB (dioctylsulfosuccinate made by Cytec Industries) 5%

Foamaster® Soap L (sodium tallowate made by Henkel) 2%

Morwet® D425 (condensed naphthalene sulfonate manufactured 5% by Witco Corporation)

10X Powdered sugar (manufactured by Imperial Sugar Co.) 13% Compound 6 and Sipernat® 50S are blended together under high shear. Other components are added, blended and milled to desired size. This surfactant wettable powder can be mixed with herbicide, moistened, extruded, dried, and broken to desired granule length.

EXAMPLE 13 A formulation containing the solid salt form of the surfactant and herbicides in the same composition can be prepared.

Sodium salt of Compound 1 46.7%

Nicosulfuron 10.7%

Thifensulfuron-methyl 1.6%

Rimsulfuron 5.3%

Morwet® D425 6.7%

Talc 6.7%

Sugar 22.3%

The ingredients are blended, milled, moistened, extruded, dried and broken to desired granule length. EXAMPLE 14 A formulation containing the surfactant in a water-soluble drying agent and herbicides in the same composition can be prepared.

Example 2, powder 65%

Nicosulfuron 8%>

Thifensulfuron-methyl 1.2%

Rimsulfuron 4%o

Foamaster® Soap L 1%

Igepon® T77 (sodium N-methyl-N-oleoyl taurate, manufactured by 5% Rhodia)

Agrimer® 15 (polyvinylpyrrolidone, manufactured by ISP) 5%

Talc 5%

Sugar 5.8%

The ingredients are blended, milled, moistened, extruded, dried and broken to desired granule length.

Claims

CLAIMS What is claimed is:

1. A herbicidal composition, comprising: at least one low-dose herbicide; at least one surfactant selected from Formula I, II or III including stereoisomers, or a mixture thereof,

COOR³

I

O-C-H II

O-C-H I COOR 4

wherein: each of R, R², R³, R⁴, R⁵, R⁶ and R⁷ are independently selected from the group consisting of H, M or (CH₂CH₂O)_xCH₂(CH₂)_yCH₃ ; R¹ is H or COOR⁷; provided that when R and R² are other than (CH₂CH₂O)_xCH₂(CH₂)_yCH₃ then R¹ is COOR⁷ and R⁷ is (CH₂CH₂O)_xCH₂(CH₂)_yCH₃; that at least one of R³ and R⁴ is (CH₂CH₂O)_xCH₂(CH2)_yCH₃; and that at least one of R⁵ and R⁶ is (CH₂CH₂O)_xCH₂(CH₂)_yCH₃; each R⁸ is independently H or OH; each M is independently an organic or inorganic cation; each x is independently an integer 4 to 50; each y is independently an integer 0 to 20; optionally at least one additive selected from the group consisting of a surfactant, an oil, an ammonium salt, a drying agent, a dispersant, a wetting agent, an anti-caking agent, an anti-foaming agent, a chemical stabilizer, an inert diluent, and an adjuvant for enhancing biological activity; and wherein the ratio of the concentration of surfactant to herbicide is about 1.5:1 to about 150:1.

2. The herbicidal composition of Claim 1 wherein the low-dose herbicide is selected from the group consisting of acetolactate synthase inhibiting herbicides, protoporphyrinogen oxidase inhibiting herbicides, -hydroxyphenylpyruvate deoxygenase inhibiting herbicides, and combinations thereof.

3. The herbicidal composition of Claim 1 wherein the composition is composed of herbicide granules and surfactant granules, the herbicide and optionally at least one additive comprising the herbicide granules; and at least one compound of Formula I, II or III and optionally at least one additive comprising the surfactant granules.

4. The composition of any one of Claims 1 to 3 wherein the surfactant is of Formula I.

5. The composition of Claim 4 wherein the surfactant is of Formula la, lb or Ic:

wherein x is 4, 7, or 9;

O

CH₂-C-O(CH₂-CH₂-O)_x-CH₂-(CH₂)╬╣o-CH₃ HO-C-COO-(CH₂-CH₂-O)_x-CH₂-(CH₂)╬╣o-CH₃ CH₂-C-O-(CH₂-CH₂-O)_x-CH₂-(CH₂)╬╣o-CH₃ O lb

wherein x is 4, 7, or 9;

0

II

CH -C-0^"M+

HO-C-COO-(CH₂-CH₂-0)_x-CH₂-(CH₂)_y-CH3

CH₂-C-╬▒(CH₂-CH₂-0)_x-CH₂-(CH₂)_y-CH3 O

Ic wherein x is 17, y is an integer 14 to 16, and M is K⁺, Na⁺ or NH4⁺

6. The composition of Claim 4 wherein the herbicide is an acetolactate synthase inhibiting herbicide.

7. The composition of Claim 6 wherein the herbicide is selected from the group consisting of: thifensulfuron-methyl, rimsulfuron and nicosulfuron; agriculturally useful salts of the foregoing; and mixtures thereof.

8. A method for controlling the growth of undesired vegetation which comprises adding the herbicidal composition of any one of Claims 1 to 3 to water and applying to the locus to be protected an effective amount of the soluble or dispersed herbicidal composition in the water.

9. The method of Claim 8 wherein the amount of surfactant and any optional adjuvant additive in the water is about 0.01 to about 0.1% weight or volume per volume of water.