WO2006087523A1

WO2006087523A1 - Agrochemical formulations

Info

Publication number: WO2006087523A1
Application number: PCT/GB2006/000457
Authority: WO
Inventors: Youry Den Tandt
Original assignee: Croda International Plc
Priority date: 2005-02-15
Filing date: 2006-02-09
Publication date: 2006-08-24
Also published as: GB0503119D0

Abstract

Agrochemical formulations use esters of the formula (I): R1-C(O)O-R2 (I) where R-1 , R2 and n have defined meanings, particularly tetrahydrofurfuryl acetate or propionate, as carrier fluids. The formulations include at least one surfactant and/or an agrochemical and can be concentrates or diluted formulations, particularly emulsions which can be sprayed onto plants or their immediate environment. The esters of the formula (I) are effective solvents which have low environmental impact.

Description

Aqrochemical Formulations

This invention relates to agrochemical formulations, particularly aqueous emulsion formulations and concentrates for such emulsion formulations and especially to formulations including particular esters, desirably including dissolved agrochemicals, and to their use in the treatment of plants. N-methyl pyrrolidone (NMP) is used as a solvent for some agrochemicals and although an effective solvent its use is being discouraged because of its adverse environmental profile and it would be desirable to find a satisfactory replacement for this agrochemical solvent.

The present invention is based on the discovery that carboxylic acid esters of alcohols substituted with oxygen containing heterocyclic groups, can be used very effectively as carrier fluids and/or solvents in agrochemical formulations and particularly for agrochemicals. The term "agrochemical" is used to refer to agrochemically active compounds and materials. Such carrier fluids and/or solvents have a superior environmental profile to NMP.

The present invention accordingly provides an agrochemical formulation, particularly an aqueous emulsion or a concentrate which is dilutable to form an aqueous emulsion, which comprises at least one ester of the formula (I):

R¹-C(O)O-(CH₂)n-R² (I) where R^ is a C-] to C-) 2. particularly a C-₎ to Cg, especially a C-_j or C₂, hydrocarbyl, particularly alkyl or alkenyl, group; R² is a 5, 6 or 7 membered, particularly 5-membered, oxygen containing heterocyclic group, desirably a saturated heterocyclic group, especially a tetrahydrofuranyl group; and n is 1 , 2 or 3, desirably 1 , and one or more surfactants and/or one or more agrochemical.

The invention includes a method of treating plants, in which a formulation of the invention, particularly an emulsion, which is the diluted form of a concentrated formulation of the invention, and which contains at least one agrochemical is sprayed onto the plants or onto the immediate environment of the plants.

The method of the invention further includes a method of treating plants by spraying onto the plants a formulation which is an aqueous emulsion of a carrier fluid which includes at least one ester of the formula (I) as defined above; at least one agrochemical; and at least one surfactant. Desirably one or more of the agrochemical(s) is(are) dissolved in the carrier fluid.

The invention includes an agrochemical formulation which includes a carrier fluid including at least one ester of the formula (I); at least one agrochemical; and at least one surfactant.

In the agrochemical formulation of the invention desirably at least one agrochemicai is dissolved in the carrier fluid. The formulation may thus take the form of emulsions, including emulsion concentrates, emulsifiable concentrates, microemulsion concentrates, suspoemulsion concentrates, or multiple emulsions. Spray formulations may be obtained by diluting concentrated formulations, particularly to give emulsions or suspoemulsions.

The invention specifically includes agrochemical formulations in one of the following forms: a an oil in water emulsion of a solution of at least one agrochemical in a water immiscible liquid which is or includes at least one ester of the formula (I); b a concentrated emulsion, which is typically diluted with water to form a diluted oil in water emulsion before use, in which at least one agrochemical is dissolved in a carrier fluid which is or includes at least one ester of the formula (I) which is emulsified in a medium, usually an aqueous medium, and which emulsion desirably includes in solution or dispersion at least one emulsifier surfactant and further desirably includes at least one adjuvant surfactant; c an emulsifiable concentrate, which is typically diluted with water to form an oil in water emulsion before use, in which at least one agrochemical is dissolved in a carrier fluid which is or includes at least one ester of the formula (I) and which desirably includes in solution or dispersion at least one emulsifier surfactant and further desirably includes at least one adjuvant surfactant; d a suspoemulsion concentrate (commonly in the art simply referred to as a "suspoemulsion"), which is typically diluted with water to form a suspoemulsion (combined suspension and emulsion) including an agrochemical in water before use, in which at least one agrochemical is dissolved in a carrier fluid which is or includes at least one ester of the formula (I), the formulation further including at least one dispersed solid, which may be at least one agrochemical (generally other than that dissolved in the carrier fluid) and which desirably includes in solution or dispersion at least one emulsifier and at least one dispersant surfactant and further desirably includes at least one adjuvant surfactant; e a microemulsion, which is typically diluted with water to form a diluted emulsion or microemulsion of an agrochemical in water before use, in which at least one agrochemical is dissolved in a carrier fluid which is or includes at least one ester of the formula (I) which is dispersed in an aqueous continuous phase in the form of a microemulsion, and which desirably includes in solution or dispersion at least one, and usually at least two, emulsifier surfactant(s) and further desirably includes at least one adjuvant surfactant;

The invention further includes spray formulations which are formed by diluting the above formulations, usually with water.

The invention also includes a method of treating vegetation in which the vegetation is sprayed by a formulation of the invention, particularly a diluted formulation, particularly in the form of an oil in water emulsion, and/or particularly a diluted concentrated emulsion, a diluted emulsifiable concentrate, a diluted suspoemulsion concentrate, and/or a diluted microemulsion. The invention further includes the use of esters of the formula (I)₁ as defined above, as carrier fluids or solvents for agrochemicals.

In esters of the formula (I) used in the invention, the substituents R¹ and R² and the index n may be varied within the specified ranges independently. R^ is desirably a C^ to Cg alkyl group, particularly C-j to C4 alkyl group, especially C-| or C2 alkyl i.e. methyl or ethyl, so that the acid R^CC^H is acetic or propionic acid. R² is desirably saturated, and (whether saturated or unsaturated) is desirably a 5-membered, heterocyclic group. Especially R² is a tetrahydrofuranyl, particularly a tetrahydrofuran-2-yl group. The group R¹ -C(O)O-(CH^)_n- is desirably a substituent on a carbon atom adjacent the oxygen atom in the heterocyclic ring, i.e. where R² is tetrahydro- furanyl, it is at the 2-position, and desirably R² is not further substituted. The index n is desirably 1 so that the esters of the formula (I) are tetrahydrofuranylmethanol esters, particularly tetrahydro- furfuryl (tetrahydrofuran-2-ylmethanol) esters .

The carrier fluid used in formulations of the invention may be wholly of one or more esters of the formula (I). However, it may be desirable to include other solvents or carrier fluids in admixture. The proportion of esters of the formula (I) is desirably from 0.1 to 100% of the solvent or carrier fluid used in the invention. As is known for NMP, some of the esters used in this invention, particularly those of the shorter chain acids and especially the acetates, notably tetrahydrofurfuryl acetate, have appreciable solubility in water and on dilution of concentrated formulations to produce a spray formulation, this component of the carrier fluid may dissolve partly or wholly in the aqueous phase. This could give rise to crystallisation or even precipitation of the agrochemical dissolved in the carrier fluid, which might result in loss of the active by sedimentation or uneven spraying caused by blockage of spray nozzles with the crystallised active. Solutions to this potential problem include using liquid active agrochemicals and/or using cσ-solvent(s) so that crystallisation is inhibited or slowed so that it is not a problem under practical spraying conditions. Co-solvents that can be used in this role include mineral oils, vegetable oils, propylene tetramer and synthetic ester oils such as lactate esters, particularly ethyl lactate and benzoate esters e.g. /so-propyl or 2-ethylhexyl benzoates. Suitable mineral oils include aromatic hydrocarbons such as xylene, oils containing aromatic hydrocarbons such as the "Solvesso" (Exxon Chemicals) and "Shellsol" (Shell Chemicals) ranges and aliphatic and paraffinic solvents such as the "Exxsol" and "Isopar" (Exxon Chemicals) ranges. Aromatic solvents can have high solvent power, but are becoming less preferred because of their potential adverse environmental impact.

Particularly in microemulsion formulations, the esters of the formula (I) may be used in combination with other polar solvents such as glycols in order to enable the use of lower proportions of total surfactant, particularly emulsifiers. When mixtures of carrier fluids or solvents are used, the proportion of ester(s) of the formula (I) used in the solvent will typically be present at from 0.5 to 99%, more usually from 1 to 98%, particularly from 2 to 95%, desirably from 10 to 90% and especially from 15 to 85% by weight of the total carrier fluid, with the other carrier fluid components or solvents typically from 99.9 to 1%, more usually from 99 to 2%, particularly from 98 to 5%, desirably 90 to 10%, and especially from 85 to 15% by weight of the total carrier fluid used. The esters of the formula (I) can also be used as solvents for components of agrochemical formulations other than the active agrochemicals. In particular, emulsifiable concentrates and microemulsion concentrates may be formulated with surfactants, especially wetters, emulsifiers and/or adjuvants to be used by dilution into a spray tank mix with the agrochemical being also added to the spray tank. When used as solvents for agrochemicals, the agrochemical can be of a wide range of materials. In particular, the agrochemical may be one or more plant growth regulators, herbicides, and/or pesticides, for example insecticides, fungicides, acaricides, nematocides, miticides, rodenticides, bactericides, molluscicides and bird repellants, particularly fungicides and/or insecticides. Generally, for water insoluble actives the esters of the formula (I) will be included primarily as solvents or carrier fluids for the active.

Water insoluble actives which can be included in the formulations of the invention include, herbicides, insecticides and fungicides and in particular: Herbicides including: bis-carbamates such as phenmedipham {3-[(methoxy-carbonyl)amino] phenyl (3-methylphenyl)- carbamate}; benzofurans such as ethofumesate {(±)-2-ethoxy-2,3-dihydro-3,3-dimethyl-5-benzofuranyl methanesulfonate}; pyridine carboxylic acids such as clopyralid {3,6-dichloropyridine-2-carboxylic acid}; nitroanilines such as trifluralin {2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl)benzenamine}; Fungicides: including azoles such as epoxiconazole {cis-1-[[3-(2-chlorophenyl)-2-(4-fluorophenyl)oxiranyl]methyl]-

1H-1,2,4-triazole}; Insecticides: including carbamates such as pirimicarb {2-(dimethylamino)-5,6-dirnethyl-4-pyrimidinyl dimethyl- carbamate}.

Combinations of more than one active which may be of one or more than one type of active may be used if desired.

Surfactant(s) can be included in the formulations of and used in the invention and can serve a variety of purposes including as wetting agents, emulsifiers, dispersants and adjuvants. Surfactants used in the formulations of the invention will usually be agrochemically compatible, which means they provide desirably surfactancy in agrochemical formulations, they can form suitably stable formulations and they are not themselves undesirably phytotoxic. Surfactants can be used in a variety of roles in agrochemical formulations, in particular as:

Wetting agents ("wetters") can be nonionic surfactants such as alcohol ethoxylates e.g. of Cg to

C-J 5, particularly primary, alcohols, which may be linear, branched or mixtures of linear and branched, particularly mono-branched, with from 5 to 30 moles of ethylene oxide; and alkoxylates of such alcohols particularly mixed ethoxylate/ propoxylates which may be block or random mixed alkoxylates, typically containing from 3 to 10 ethylene oxide residues and from 1 to 5 propylene oxide residues, particularly where the polyalkoxylate chain is terminated with propylene oxide unit(s); polyoxyethylene/polyoxypropylene copolymers, particularly block copolymers, such as the Synperonic PE series of copolymers available from Uniqema, and alkyl polysaccharides; silicone based surfactants; anionic surfactants e.g. isethionates, such as sodium cocoyl isethionate, naphthalene sulphonic acids or sulphosuccinates.

Emulsifiers can be anionic surfactants e.g. alkali metal or alkali earth metal salts of sulphonated hydrocarbons such as alkyl benzene sulphonates particularly Ca dodecylbenzene sulphonate e.g. Atlox 4838B available from Uniqema; and/or non-ionic surfactants including alcohol alkoxylates such as those based on Cs to C22₁ particularly C-] 2 to C-\ Q, alcohols, which may have straight or branched, usually alkyl, chains, and which are alkoxylated with ethylene oxide, propylene oxide or copolymeric chains including residues of both ethylene oxide and propylene oxide, which may be block or random (statistical) copolymeric chains, commercially available examples include: Atlox MBA 1306 and the Synperonic A series available from Uniqema, ranging from the low HLB (Hydrophile Lipophile Balance) emulsifiers such as Synperonic A3 and A4, through mid range HLB emulsifiers to high HLB emulsifiers such as Synperonic A20; EO/PO block copolymers such as Atlas G-5000 available from Uniqema; polyalkoxylated fatty acids based on Cβ to C221 particularly C-] 2 to

C18. fatty acids; sorbitan and sorbitol esters, e.g. sorbitan monolaurate and monooleate; poly(alkoxylated) derivatives of sorbitan and sorbitol esters; and poly(alkoxylated) fatty amines such as tallow amine ethoxylates. The ranges of non-ionic surfactants can encompass both water in oil and oil in water emulsifiers; generally the former have relatively long hydrophobes and/or small hydrophiles, particularly polyethylenoxy, chains and the latter have relatively shorter hydrophobes and/or larger hydrophiles.

Dispersants (dispersing agents) for dispersing solids in water include naphthalene sulphonate formaldehyde condenses e.g. as sodium and ammonium salts; sodium, lignosulphonates e.g. as calcium and ammonium salts; maleic anhydride copolymers e.g. as sodium and ammonium salts; condensed phenolsulphonic acid e.g. as sodium salts; sulphonated polystyrenes; acrylic acid styrene copolymers; and acrylic graft copolymers, particularly with polyethylene glycols; and for dispersing solids in oil phases or solvents condensed fatty acid surfactants such as polycoπdensed fatty acids and/or their quaternary ammonium and/or alkaline earth metal and/or amine derivatives and polyamine / fatty acid condensate solutions; polyoxyalkylene amine derivatives; polyester polyether block copolymers; and polyalkylene glycol ethers. Adjuvants can be non-ionic surfactant adjuvants such as the so-called hydrocarbyl, particularly alkyl e.g. Cg to C^, especially from Cg to C^ alkyl, polysaccharides (generally more correctly described as oligosaccharides), typically having an average of from 1 to 3, more usually from 1.3 to 2 saccharide units in the oligosaccharide chain; hydrocarbyl, particularly alkyl, amine alkoxylates, particularly ethoxylates; linear or mono-branched (or mixed) alcohol alkoxylates, particularly ethoxylates; sorbitol and sorbitan fatty acid esters and their alkoxylated, particularly ethoxylated derivatives. Further adjuvants include amphoteric surfactants such as betaines and cationic surfactants such as long chain alkyl e.g. C^ 2 to C22, particularly C14 to C-ig alkyl. quaternary ammonium compounds. Coadjuvants, such as ionic and/or inorganic materials, for example ammonium sulphate, may be included in adjuvant containing agrochemical formulations of the invention, particularly with non-ionic surfactant adjuvants.

The proportions of materials used in formulations of and used in this invention depend on the intended end use and a range of these are described below. In these the terms "solvent" and "carrier fluid" refer to an organic solvent or carrier fluid which includes at least one ester of formula (I) and "emulsifiers", "dispersants", "wetters" and "adjuvants are particularly materials as described above.

For formulations including active agrochemicals, the compositions will depend on the form of the formulation, particularly for concentrate formulations. In principle, spray formulations including esters of the formula (I) can be made up in situ in the spray tank from the individual components. However, this is generally not convenient as it requires the end user to have suitable (relatively high intensity) mixing equipment. More usually the agrochemical and surfactant components will be incorporated in preformulated concentrate compositions which can be diluted with water at the point of use to form sprayable formulations requiring no or only moderate mixing. In practice such concentrates need to have sufficient stability that they can be satisfactorily dispersed into spray formulations when diluted with water desirably without requiring substantial additional mixing, beyond stirring on dilution. This typically means that such formulations remain stable for a minimum of 1 day and desirably for at least one week and more usually at least 1 month. For emulsions remaining stable means that they do not break or separate (other than slight creaming that is readily redispersed) and for solution or microemulsion formulations that they remain visually stable and homogeneous.

Agrochemical concentrated emulsions are emulsions formulations which on dilution (in water) give emulsions with a continuous aqueous phase. The concentrate formulation is in effect just more concentrated (having less water) than the diluted (spray) formulation. They have limited practicality because of the difficulty in formulating the concentrates with very high internal phase volumes. More usually concentrates dilutable to give emulsion spray formulations are commercially formulated as emulsifiable concentrates or microemulsion concentrates.

Emulsifiable concentrates are oil based concentrates which on dilution with water spontaneously or very readily form oil in water emulsions, typically of an agrochemical dissolved in an oil, in the water phase. They are also sometimes described as "built-in concentrates". The surfactant(s) in emulsion concentrates act(s) to form a homogeneous concentrate that readily or spontaneously emulsifies on dilution into water. Technically the concentrate may be a true solution or a micro- emulsion, but on dilution in water forms a macroemulsion i.e. a visibly cloudy emulsion. The surfactant is often a combination of two or more surfactant compounds including emulsifiers to stabilise the emulsion formed on dilution and may also include adjuvant surfactants. Typical ranges for the main components of emulsifiable concentrates are:

Agrochemical suspoemulsion concentrates are formulations which on dilution (in water) give suspoemulsions i.e. which include at least one liquid (emulsion) disperse phase and at least one solid disperse phase, in a continuous aqueous phase. The concentrate formulation can itself be a suspoemulsion, in effect just more concentrated (having less water) than the diluted (spray) formulation; or it may be a dispersion of a solid disperse phase in an emulsifiable concentrate, which on dilution forms an emulsion. They are particularly suitable for agrochemical formulations which include an oil soluble active, present as a solution in the oil emulsion disperse phase, and a solid water insoluble (and usually also oil insoluble) active, i.e. the solid components usually include an agrochemical, present as dispersed particles, although other formulation components may also be present as dispersed solid particles. The solid dispersed phase may be dispersed within the oil based emulsion droplets. Suspoemulsions are typically based on an oil solution of one agrochemical also including a solid water insoluble active or other solid component present as dispersed particles. They usually include surfactant(s) as emulsifiers, particularly oil in water emulsifiers, to stabilise the emulsion formed on dilution in water to normal spray concentration, and as dispersant for the solid particles in the oil phase and/or the aqueous phase. Suspoemulsion concentrates are typically diluted in water for spray application to form suspoemulsions. Overall the composition of suspoemulsion concentrates are typically as set out below:

Microemulsions are thermodynamically stable, transparent concentrate formulations which include a liquid dispersed emulsion phase with a droplet size fine enough not to scatter visible light e.g. less than 0.1 μm. They include surfactants to stabilise the microemulsion particularly emulsifiers and may also include adjuvants. Microemulsions are typically diluted into water usually to form microemulsion spray formulations (formulations that form emulsions are more usually designated as emulsifiable concentrates even where technically the concentrate is itself a microemulsion) before spraying. Overall typical microemulsion compositions are as set out below:

The esters of the formula (I) can be included in agrochemical spray formulations by additions to the aqueous based tank mix, in effect immediately before spraying. In such situations, the addition will usually be as a crop oil that acts to improve the overall effectiveness of the agrochemical spray. The proportion of the crop oil used in this way is typically from 0.02 to 2 %, more usually from 0.2 to 1 %, by weight of the overall spray formulation. The formulation will usually include emulsifier surfactant to aid dispersion of the crop oil as an emulsion in the spray formulation. The esters of the formula (I) can be used alone or in combination with other crop oils, usually within the composition ranges set out above for oil mixtures. For tank addition in this way, the oil, including the esters of the formula (I), may also include some or all of the adjuvant surfactant added to the spray formulation and in this approach the oil acts as a carrier fluid (or solvent) for the adjuvant surfactant (as well as potentially as a crop oil). Overall the typical composition of such crop oil / carrier fluid systems are as set out below.

The esters of the formula (I) can be included in agrochemical spray formulations by additions to the aqueous based tank mix, in effect immediately before spraying. For tank addition in this way, the oil, including the esters of the formula (I), may also include some or all of the adjuvant surfactant added to the spray formulation and in this approach the oil acts as a carrier fluid (or solvent) for the adjuvant surfactant and will often include emulsifiers and possibly wetters. Overall the typical composition of such systems are as set out below:

Concentrated forms of agrochemical formulations, including adjuvant concentrates, are usually diluted with water to make sprayable diluted aqueous formulations. Typically the dilution rate is from 10 to 10000, particularly 30 to 1000, times by volume. The dilution rate is chosen to match the required spray volume to the desired application rate of the agrochemical formulation.

The invention includes a method of making a diluted agrochemical formulation for spraying (spray tank mix) which includes diluting a concentrate containing at least one active agrochemical, particularly one or more emulsion concentrate, emulsifiable concentrate, suspension concentrate, suspoemulsion concentrate, microemulsion and/or multiple emulsion, which concentrate also includes at least one ester of the formula (I) with water.

The invention also includes a method of making a diluted agrochemical formulation for spraying (spray tank mix) which includes mixing in any order: a) a concentrate containing at least one active agrochemical, particularly one or more emulsion concentrate, emulsifiable concentrate, suspension concentrate, suspoemulsion concentrate, microemulsion and/or multiple emulsion; b) a solution or dispersion of a surfactant, particularly an adjuvant surfactant, in a carrier fluid; and c) water, particularly in an amount of from 10 to 10000 times by volume of the combined volume of components a and b; to form the diluted agrochemical formulation, wherein at least one of component a) and component b) including at least one ester of the formula (I). The application rate of diluted formulations, where the bulk of the spray is dilution water, is typically from 50 to 500, more usually from 50 to 400 and commonly about 300, l(spray formulation), ha^'^crop treated). For more concentrated forms of spray e.g. as in neat winter crop oil spraying or ultra low volume spraying, the application rate may be significantly lower typically 0.5 to 50, more usually 1 to 10, l(spray formulation), ha'^'' (crop treated).

In agrochemical sprays, particularly as diluted water based sprays, the concentration of the active agrochemical is typically from about 0.001 to about 3%, more usually from 0.1 to about 0.5 and particularly about 0.2% by weight of the spray formulation. When used the typical concentration of adjuvant is from 0.02 to about 2%, more usually 0.2 to about 1% and particularly about 0.1%. Typically the weight ratio of active agrochemical to adjuvant is usually from 1 :100 to 10:1, more usually from 1 :10 to about 4:1. These figures correspond to crop application rates of the active agrochemical generally in the range 0.5 to 4000 g.ha"¹ , more usually from 3 to about 2000 g.ha^'1 (the actual amount depending on the particular crop, agrochemical and effect desired). For low volume spraying, generally higher spray concentrations will be used, but the ratio of agrochemical to adjuvant will be within the ranges given above.

Other potential components of agrochemical formulations of and used in this invention include: thickeners or rheology modifiers are commonly used in liquid concentrate formulations, to stabilise the concentrate against settling, flocculation or phase separation prior to dilution. The amount of thickener used is typically from 0.01 to 5% by weight of the formulation. antifoams, particularly silicon based materials such as organopolysiloxanes, typically used in an amount from 0.1 to 10%, preferably 0.2 to 6% by weight of the surfactant; 0.01 to 5%, particularly 0.02 to 2% by weight of agrochemical concentrate and 0.0001 to 0.1% preferably 0.001 to 0.05% by weight of a spray formulation at end use dilution; viscosity modifiers, particularly gums such as xanthan gums; cellulose derivatives, such as carboxyl-methyl, -ethyl, or -propyl cellulose, typically used at from 0.01 to 5 wt % of a concentrated formulation; and other non surfactant materials such as stabilisers and/or anti-microbials, typically used at from 0.01 to 5 wt % of a concentrated formulation. cold stabilisers, particularly mono propylene glycol, typically used at from 5 to 20 wt % of a concentrated formulation. The following Examples illustrate the invention. All parts and percentages are by weight unless otherwise stated.

Materials

Actives

Act1 ethofumesate ex Agrevo

Act2 clopyralid ex Dow Agrosciences

Act3 pirimicarb ex Syngenta

Act4 phenmedipham ex Agrevo

Act5 epoxyconazole ex BASF

Act6 trifluoralin ex Monsanto

Solvents

SoH furfur-1-yl acetate

Sol2 furfur-1-yl butyrate

CsoH N-methyl pyrrolidone

Exam pie 1 The effectiveness of furful-1 -yl acetate (Soli ) and furful-1 -yl butyrate (Sol2) as solvents for agrochemicals was tested. Solid samples of the active ingredients under test were weighed and an attempt to dissolve them in an amount of the test solvents to give a concentration corresponding to typical concentrations of the active as used in conventional solvents. The solid and solvent were mixed, shaken intensively, left to stand for 24 hours, again intensively shaken and the liquid supernatant separated from any remaining solid by centrifugation. The amount of the active that dissolved in the solvent was assessed by weighting the liquid phase separated in the centrifuge. The solvency power of the solvent was rated on a ten point scale ranging from 0 (less than 5% active dissolved) to 9 (85 to 100% active dissolved). The results of this testing are set out in Table 1 below. In the Table the actives are given with the target concentration in g.l"¹. Table 1

These results indicate that these tetrahydrofurfuryl esters can be effective solvents, and could replace NMP used conventionally as a solvent, for these agrochemicals in formulations, particularly emulsions, concentrated emulsions, emulsion concentrates, microemulsion concentrates and suspoemulsion concentrates.

Claims

I An agrochemical formulation which comprises a carrier fluid which is or includes at least one ester of the formula (I):

R¹-C(O)O-(CH₂)_n-R² (I) where

R¹ is a C-i to C-] 2 hydrocarbyl group;

R2 is a 5, 6 or 7 membered oxygen containing heterocyclic group; and n is 1 , 2 or 3, and one or more surfactants and/or one or more agrochemical. 2 A formulation as claimed in claim 1 wherein in formula (I):

R^ is a C-] to CQ, particularly a C^ or C2 alkyl or alkenyl, group;

R2 is a saturated heterocyclic group, particularly a tetrahydrofuranyl group; and n is 1.

3 A formulation as claimed in either claim 1 or claim 2 wherein at least one of the agrochemical is one or more of a herbicide, fungicide and/or insecticide and the surfactant is one or more welters, emulsifiers, dispersants and/or adjuvants.

4 A formulation as claimed in any one of claims 1 to 3 which additionally includes a co-solvent.

5 A formulation as claimed in claim 4 wherein the co-solvent is one or more mineral oils, vegetable oils, propylene tetramer and/or synthetic ester oils. 6 A formulation as claimed in any one of claims 1 to 5 wherein the carrier fluid includes at least 25% by weight of the total carrier fluid of an ester of the formula (I).

7 A formulation as claimed in any one of claims 1 to 6 in the form of a concentrated emulsion, an emulsifiable concentrate, a microemulsion concentrate or a suspoemulsion concentrate.

8 A formulation as claimed in any one of claims 1 to 6 in the form of a diluted concentrated emulsion, emulsifiable concentrate, microemulsion concentrate or suspoemulsion concentrate.

9 A formulation as claimed in claim 8 wherein the concentrated emulsion, emulsifiable concentrate, microemulsion concentrate or suspoemulsion concentrate is diluted by from 10 to 10000 time by volume with water. 10 A method of treating plants, in which a composition as claimed in any one of claims 1 to 9 is sprayed onto the plants or onto the immediate environment of the plants.

II A method of making a diluted agrochemical formulation which includes mixing in any order: a) a concentrate containing at least one active agrochemical, particularly one or more emulsion concentrate, emulsifiable concentrate, suspension concentrate, suspoemulsion concentrate, microemulsion and/or multiple emulsion; b) a solution or dispersion of a surfactant, particularly an adjuvant surfactant, in a carrier fluid; and c) water, particularly in an amount of from 10 to 10000 times by volume of the combined volume of components a) and b); to form the diluted agrochemical formulation, wherein at least one of component a) and component b) including at least one ester of the formula (I). A method of treating plants which comprises spraying the plant or the immediate environment of the plant with a diluted agrochemical formulation as claimed in either claim 8 or claim 9 or made by the method claimed in claim 11.