LACTONES AS SOLVENTS IN AGROCHEMICAL FORMULATIONS

Abstract

The present invention relates to the use of a water soluble lactone-derivative as a solvent in agrochemical formulations, as well as to such formulations per se in both concentrated and dilute form, and methods of making such formulations. In particular the invention relates to such formulations (and more specifically still, emulsifiable concentrates and/or emulsions or microemulsions) comprising a lactone derivative having six-carbon atoms and at least one pesticidally active agrochemical ingredient selected from the group consisting of a herbicide, safener, insecticide, fungicide, nematicide, molluscicide, and a plant growth regulator.

Claims

1-15. (canceled)

16. An agrochemical composition wherein the composition is an emulsion concentrate (EC) or an emulsion in water (EW), comprising: (i) an agrochemical active ingredient; and (ii) gamma caprolactone or 2-acetyl-gamma-butyrolactone; wherein the agrochemical active ingredient of (i) is dissolved gamma caprolactone or 2-acetyl-gamma-butyrolactone of (ii).

17. The agrochemical composition of claim 16, additionally comprising a surfactant.

18. The agrochemical composition according claim 16, wherein the agrochemical active ingredient is a herbicide, safener, insecticide, fungicide, nematicide, molluscicide, or plant growth regulator.

19. The agrochemical composition according to claim 16, wherein the agrochemical active ingredient is a herbicide, safener, insecticide or fungicide.

20. The agrochemical composition according to claim 16 wherein the agrochemical active ingredient has an aqueous solubility of less than 10 g/1 at 20 C.

21. Use of gamma caprolactone or 2-acetyl-gamma-butyrolactone as a solvent for a pesticidally active agrochemical active ingredient, in an emulsifiable concentrate, emulsion in water or microemulsion.

22. A method of making an agrochemical composition that is an emulsifiable concentrate, emulsion in water or microemulsion, which comprises (i) dissolving an agrochemical active ingredient in gamma caprolactone or 2-acetyl-gamma-butyrolactone; and (ii) combining the solution of (i) with water or other aqueous solvent that is immiscible with the gamma caprolactone or 2-acetyl-gamma-butyrolactone employed in (i).

23. A method of controlling a pest, comprising applying an agrochemical composition as defined in claim 16, to said pest or the locus of said pest.

24. A method of treatment or prevention of a fungal infection in a plant comprising applying to said plant or the locus of said plant, a composition comprising a fungicidal active ingredient dissolved in gamma caprolactone or 2-acetyl-gamma-butyrolactone.

25. A method for the control of insects in plants, comprising applying to said plant or the locus of said plant, a composition comprising an insecticidal active ingredient dissolved gamma caprolactone or 2-acetyl-gamma-butyrolactone.

26. A method for the control of unwanted plant growth, comprising applying to said plant or the locus of said plant, a composition comprising a herbicidal active ingredient dissolved in gamma caprolactone or 2-acetyl-gamma-butyrolactone.

Description

EXAMPLES

Example 1 -Lactone Aqueous Solubility and Log P Octanol

1.1 Aqueous Solubility

[0035] The aqueous solubility of gamma caprolactone was measured using HPLC chromatography. Several samples of the lactone were equilibrated at room temperature with an equal volume of water. The samples were left for two weeks then analysed by HPLC. The results of the repeat measurements are shown below in Table 1, and it can be seen quite clearly that the aqueous solubility of gamma caprolactone is approximately 11% w/w.

TABLE-US-00001 TABLE 1 Aqueous solubility of -caprolactone. Two sets of measurements taken to establish the aqueous solubility of gamma caprolactone, are tabulated below along with the calculated mean and % RSD. Aqueous solubility (% w/w) Sample Measurement Mean % RSD 26 10.915 11.01 1.34 28 11.018 30 11.146 32 10.938 34 11.209 36 10.821 38 10.923 10.93 1.25 40 10.714 42 10.954 44 11.078 46 11.059 48 10.840

1.2 Log P Octanol for -Caprolactone

[0036] Samples of gamma caprolactone were examined using an octanol saturated chromatography column. The retention time on the column indicated an octanol water partition coefficient (log P octanol) of 0.34 at a temperature of 25 C. and a pH of 6.98.

Example 2 Solubility of the Fungicide Azoxystrobin in a Range of Organic Liquids

[0037] Azoxystrobin was dissolved in a range of organic liquids, some of which are known to be solvents for agrochemicals, at room temperature and allowed to equilibrate. A measured quantity of water was added and each mixture was shaken. The volume of water was 20 times greater than the volume of organic liquid/solvent. After settling the samples were assessed as being either (i) split into two layers with no evidence of pesticide crystalisation, or (ii) identified as a single layer where the pesticide had precipitated out as crystals.

[0038] Samples were assessed after 24 and 48 hours. The results after 48 hours are shown in Table 2. The log P octanol values for the solvents have been taken from the literature or, where this value was not available, were estimated using the program ProPred (ICAS ProPred, KT Consortium, DTU Kemiteknik, Lyngby, Denmark). Where values were estimated, a simple check was carried out using measuring cylinders with 50/50 volumes of octanol and water. Solvent was added to the cylinder until a clear observation of the effect of the addition was apparent.

TABLE-US-00002 TABLE 2 Azoxystrobin solubility in a range of organic liquids. Organic liquids having a range of logP octanol values were used as solvents for the fungicide azoxystrobin. The solubility of azoxystrobin was assessed visually at 48 hours. SOLVENT logP octanol APPEARANCE Ethylene glycol 0.78 Crystallised Dipropylene glycol 0.76 Crystallised 2-acetyl-gamma-butyrolactone 0.72 2 layers -Butyrolactone 0.60 Crystallised Methyl lactate 0.47 Crystallised -Valerolactone 0.26 Crystallised Dimethyl lactamide 0.22 Crystallised -Valerolactone** 0.21 Crystallised Triethyl phosphate 0.28 Crystallised Dowanol TPM 0.31 Crystallised -Caprolactone 0.34 2 layer Hexylene glycol 0.44 Crystallised Dipropylene glycol monomethyl ether 0.46 Crystallised -Caprolactone 0.70 Crystallised Propylene glycol diacetate 0.94 Crystallised Propylene glycol n-butyl ether 1.15 2 layer Butylene carbonate 1.21 2 layer Diethylene carbonate 1.21 2 layer Cyclohexanol 1.23 2 layer Propyl lactate 1.29 2 layer Triacetin 1.30 2 layer Benzyl alcohol 1.46 2 layer Diethyl fumarate 1.51 2 layer Acetophenone 1.58 2 layer Methyl benzoate 1.85 2 layer Diethylene glycol hexyl ether 2.16 2 layer Propyl benzoate 3.01 2 layer Butyl benzoate 3.20 2 layer **gamma valerolactone initially formed two layers immediately on addition to water, but the sample crystallised over 48 hours

[0039] Surprisingly, the solutions of azoxystrobin in gamma caprolactone or 2-acetyl-gamma-butyrolactone resulted in biphasic mixtures, wherein the pesticide remained dissolved in the solvent and this solution was not water soluble.

[0040] The gamma caprolactone sample with azoxystrobin was further diluted 100-fold in water with the result that that the two layers still did not become miscible.

Example 3 Comparison of Pesticide Solubility in Organic Liquids Having Similar Aqueous Solubility and Log P Octanol

[0041] The two solvents DowanolTPM (tripropylene glycol methyl ether, The Dow Chemical Company) and hexylene glycol are similar to -caprolactone in their log P octanol values and are also fully miscible with water at 20 C. In this example several pesticidally active agrochemical ingredients (mandipropamid, fludioxonil, pinoxaden, and difenoconazole) were dissolved in each of the three solvents to give solutions of 5% w/w. Each solution was then diluted into water to form a 20:1 mixture. The resulting observations are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Comparative solubility of a range of agrochemical active ingredients in solvents having similar aqueous solubility characteristics. After settling the solutions of mandipropamid, fludixonil, pinoxaden and difenoconazole were assessed as being either (i) split into two layers (2-layers) with no evidence of pesticide crystalisation, or (ii) identified as a single layer where the pesticide had precipitated out as crystals (crystallised). Agrochemical Active Ingredient: APPEARANCE OF FORMULATION SOLVENT (logP octanol) Mandipropamid Fludioxonil Pinoxaden Difenoconazole Dowanol TPM (0.31) Crystallised Crystallised Crystallised Crystallised -Caprolactone (0.34) 2 layer 2 layers 2 layers 2 layers Hexylene glycol (0.44) Crystallised Crystallised Crystallised Crystallised

[0042] Unsurprisingly, the formulations employing DowanolTPM and hexylene glycol as solvents, resulted in crystallisation of each of the agrochemical active ingredients. Gamma caprolactone alone was capable of retaining each of the agrochemical active ingredients in solution, and presented as a two-layer system.

Example 4 Solubility of Agrochemicals in -Caprolactone

[0043] A small amount of each of the agrochemical active ingredients listed in Table 4 below, was added to, and dissolved in, gamma caprolactone as solvent. The surfactant Soprophor 3D33 (tristyrylphenol ethoxylate phosphate ester, SOLVAY) was then added to 5% w/w. The resulting samples were diluted in water, and all were seen to emulsify readily.

TABLE-US-00004 TABLE 4 Agrochemical Active Ingredients Acetamiprid 3-difluoromethyl-1-methyl-1H-pyrazole-4-carboxylic acid methoxy-[1-methyl-2-(2,4,6-trichlorophenyl)-ethyl]-amide Atrazine Butafenacil Cloquintocet mexyl N-(2-methoxybenzoyl)-4-[(methylaminocarbonyl)amino]ben- zenesulfonamide Cyflufenamid Cyproconazole Cyprodinil Difenoconazole Epoxiconazole Fludioxynil Isopyrazam Mandipropamid Napropamide Oxyfluorfen Pinoxaden Prometryn Propiconazole Pyribenzoxim Solatenol Terbuthylazine Thiamethoxam Trinexapac ethyl

Example 5 Preparation of an Agrochemical EC Formulation of Using -Caprolactone as Solvent

[0044] In this example, an EC formulation of azoxystrobin was prepared with the composition as described in Table 5 below. The ingredients were mixed together to form a clear solution. The EC was shown to be stable at room temperature for two weeks.

[0045] The emulsion characteristics were examined on dilution into water. The formulation emulsified readily in water and showed good emulsion stability over 24 hours at a dilution level of 1:100.

TABLE-US-00005 TABLE 5 Composition of EC containing azoxystrobin Component Role Amount (w/v) Azoxystrobin Active ingredient (fungicide) 20 Soprophor BSU Surfactant 8 -caprolactone Solvent 32 Dimethyl lactamide Solvent 40

Example 6 Formulation of a Mixture of Two Agrochemicals as an EC Using -Caprolactone as Solvent

[0046] In this example an EC formulation of two fungicides was prepared by combining the two fungicidal active ingredients, azoxystrobin and solatenol, with gamma caprolactone and a second solvent, dimethyl lactamide. The ingredients were mixed together to form a clear solution. A small amount of the surfactant Soprophor 4D384 (tristyrylphenol ethoxylate sulphate, SOLVAY) was added to the solution and the emulsion characteristics examined on dilution into water. At a dilution of 1/100 the emulsion was stable for 24 hours.

Example 7 Formulation of Four Agrochemicals as an EC Using -Caprolactone as Solvent

[0047] In this example a complex EC was formed, which contained three herbicides and a herbicide safener. The components described in Table 6 below were mixed together to form an EC. The resulting EC diluted easily into water and formed a milky white emulsion.

[0048] After standing for 24 hours there was a small (negligible) amount of settling from the emulsion, which was otherwise observed to be stable.

TABLE-US-00006 TABLE 6 Composition of EC comprising four agrochemical active ingredients Component Role Amount (w/v) Pinoxaden (acid form) Active ingredient (herbicide) 6 Bicyclopyrone Active ingredient (herbicide) 10 Bromoxynil Active ingredient (herbicide) 20 Cloquintocet-mexyl Active ingredient (safener) 15 Triethanolamine Surfactant 5.7 AtlasG-5004-LD Surfactant 5 SERVIROX OEG 59E Surfactant 2 SynperonicPE/L 64 Surfactant 3 Dimethyl lactamide Solvent 18 -caprolactone Solvent 15.3