LIQUID SULFONYLUREA-CONTAINING HERBICIDAL COMPOSITIONS

Abstract

This invention relates to a liquid herbicidal composition comprising a non-aqueous solvent system, at least one sulfonylurea herbicide and at least one inorganic salt selected from the metal carbonates and metal phosphates. The invention also relates to the use of an inorganic salt selected from the metal carbonates and metal phosphates to improve chemical stabilisation of a sulfonylurea herbicide in a liquid composition comprising a non-aqueous solvent system.

Claims

1. A liquid herbicidal composition comprising: a non-aqueous solvent system; at least one sulfonylurea herbicide; and at least one inorganic salt selected from the metal carbonates and metal phosphates.

2. The composition according to claim 1, wherein the inorganic salt is selected from alkali metal phosphates and alkali metal carbonates.

3. The composition according to claim 1, wherein the inorganic salt comprises a metal selected from Na, K, Ca, Mg or Al.

4. The composition according to any one of claims 1 to 3, wherein the inorganic salt is selected from Na.sub.3PO.sub.4, K.sub.3PO.sub.4, Mg.sub.3(PO.sub.4).sub.2, AlPO.sub.4, and Na.sub.2CO.sub.3.

5. The composition according to any one of claims 1 to 4, which is formulated as an oil dispersion (OD), a dispersible concentrate (DC), an emulsifiable concentrate (EC), or a soluble concentrate (SL).

6. The composition according to any one of claims 1 to 5, which is formulated as an oil dispersion (OD) and wherein at least one sulfonylurea is suspended in the non-aqueous solvent system.

7. The composition according to any one of claims 1 to 6, wherein at least one inorganic salt is suspended in the non-aqueous solvent system.

8. The composition according to any one of claims 1 to 7, wherein the sulfonylurea herbicide is selected from amidosulfuron, azimsulfuron, bensulfuron, chlorimuron, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron, ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron, foramsulfuron, halosulfuron, imazosulfuron, iodosulfuron, iofensulfuron, mesosulfuron, metazosulfuron, metsulfuron, nicosulfuron, orthosulfamuron, oxasulfuron, primisulfuron, propyrisulfuron, prosulfuron, pyrazosulfuron, rimsulfuron, sulfometuron, sulfosulfuron, thifensulfuron, triasulfuron, tribenuron, triloxysulfuron, triflusulfuron and tritosulfuron, or salts or esters thereof.

9. The composition according to any one of claims 1 to 8, wherein: the at least one inorganic salt is Na.sub.3PO.sub.4 and the at least one sulfonyl urea is selected from tribenuron-methyl, metsulfuron-methyl, nicosulfuron, bensulfuron-methyl, foramsulfuron, pyrazosulfuron-ethyl, chlorsulfuron, amidosulfuron, and triasulfuron; or the at least one inorganic salt is Na.sub.2CO.sub.3, and the at least one sulfonyl urea is selected from tribenuron-methyl and nicosulfuron; or the at least one inorganic salt is Mg.sub.3(PO.sub.4).sub.2 and the at least one sulfonyl urea is selected from rimsulfuron, bensulfuron-methyl, mesosulfuron-methyl, thifensulfuron-methyl, chlorimuron-ethyl, and triasulfuron; or the at least one inorganic salt is AlPO.sub.4 and the at least one sulfonyl urea is metsulfuron-methyl, halosulfuron-methyl or rimsulfuron.

10. The composition according to any one of claims 1 to 9, wherein the at least one sulfonylurea herbicide is not nicosulfuron and/or not a pyridylsulfonylurea.

11. The composition according to any one of claims 1 to 10, comprising at least one non-sulfonylurea herbicidal compound.

12. The composition according to claim 11, wherein at least one non-sulfonylurea herbicidal compound is dissolved in the non-aqueous solvent system.

13. The composition according to claim 11 or 12, wherein the non-sulfonylurea herbicidal compound is selected from 2,4-D, 2,4-DB, 2,3,6-TBA, acetochlor, acifluorfen, acifluorfen-sodium, aclonifen, alachlor, alloxydim, alloxydim-sodium, ametryn, amicarbazone, aminopyralid, amitrole, anilofos, asulam, atrazine, azafenidin, beflubutamid, benazolin,-benazolin-ethyl, benfuresate, bentazone, benzfendizone, benzobicyclon, benzofenap, bifenox, bilanafos, bispyribac-sodium, bromacil, bromobutide, bromofenoxim, bromoxynil, butachlor, butafenacil, butenachlor, butralin, butroxydim, butylate, cafenstrole, carbetamide, carfentrazone-ethyl, chlomethoxyfen, chloridazon, chlornitrofen, chlorotoluron, cinidon-ethyl, cinmethylin, clefoxydim, clethodim, clodinafop-propargyl, clomazone, clomeprop, clopyralid, cloransulam-ethyl, cumyluron, cyanazine, cycloxydim, cyhalofop-butyl, daimuron, dazomet, desmedipham, dicamba, dichlobenil, dichlorprop, dichlorprop-P, diclofop-methyl, diclosulam, difenzoquat, diflufenican, diflufenzopyr, dikegulac-sodium, dimefuron, dimepiperate, dimethachlor, dimethametryn, dimethenamid, diquat-dibromide, dithiopyr, diuron, dymron, EPTC, esprocarb, ethalfluralin, ethofumesate, ethoxyfen, etobenzanid, fenoxaprop-ethyl, fenoxaprop-P-ethyl, fentrazamide, flamprop-M-isopropyl, flamprop-M-methyl, florasulam, fluazifop, fluazifop-butyl, fluazolate, flucarbazone-sodium, fluchloralin, flufenacct, flufenpyr, flumetsulam, flumiclorac-pentyl, flumioxazin, fluomcturon, fluorochloridone, fluoroglycofen-ethyl, flupoxam, fluridone, fluroxypyr, fluroxypyr-butoxypropyl, fluroxypyr-meptyl, fluprimidol, flurtamone, fluthiacet-methyl, fomesafen, glufosinate, glufosinate-ammonium, glyphosate, haloxyfop, haloxyfop-ethoxyethyl, haloxyfop-methyl, haloxyfop-P-methyl, hexazinone, imazamethabenz-methyl, imazamox, imazapic, imazapyr, imazaquin, imazethapyr, indanofan, ioxynil, isoproturon, isouron, isoxaben, isoxachlortole, isoxaflutole, ketospiradox, lactofen, lenacil, linuron, MCPA, MCPB, mecoprop, mecoprop-P, mefenacet, mesotrione, metamifop, mctamitron, metazachlor, methabenzthiazuron, methyldymron, metobromuron, metolachlor, metosulam, metoxuron, metribuzin, molinate, monolinuron, naproanilide, napropamide, neburon, norflurazon, orbencarb, oryzalin, oxadiargyl, oxadiazon, oxaziclomefone, oxyfluorfen, paraquat, pelargonic acid, pendimethalin, pendralin, penoxsulam, pentoxazone, pethoxamid, phenmedipham, picloram, picolinafen, pinoxaden, piperophos, pretilachlor, profluazol, profoxydim, prometryn, propachlor, propanil, propaquizafop, propisochlor, propoxycarbazone-sodium, propyzamide, prosulfocarb, pyraclonil, pyraflufen-ethyl, pyrazolate, pyrazoxyfen, pyribenzoxim, pyributicarb, pyridafol, pyridate, pyriftalid, pyriminobac-methyl, pyrithiobac-sodium, quinclorac, quinmerac, quinoclamine, quizalofop-ethyl, quizalofop-P-ethyl, quizalofop-P-tefuryl, sethoxydim, simazine, simetryn, S-metolachlor, sulcotrione, sulfentrazone, sulfosate, tebuthiuron, tepraloxydim, terbuthylazine, terbutryn, thenylchlor, thiazopyr, thiobencarb, tiocarbazil, tralkoxydim, triallate, triaziflam, triclopyr, tridiphane, and trifluralin.

14. The composition according to any one of claims 1 to 13, comprising at least two sulfonylurea compounds, wherein the sulfonylurea compounds are selected from: nicosulfuron and thifensulfuron methyl; nicosulfuron and prosulfuron; metsulfuron methyl and iodosulfuron methyl; metsulfuron methyl and sulfosulfuron; metsulfuron methyl and thifensulfuron methyl; metsulfuron methyl and bensulfuron methyl; metsulfuron methyl and chlorsulfuron; metsulfuron methyl and chlorimuron ethyl; metsulfuron methyl and tribenuron-methyl; tribenuron-methyl and thifensulfuron methyl; tribenuron-methyl and chlorimuron ethyl; tribenuron-methyl and bensulfuron-methyl; tribenuron-methyl and mesosulfuron; tribenuron-methyl and iodosulfuron-methyl; iodosulfuron methyl and mesosulfuron methyl; iodosulfuron methyl and amidosulfuron; iodosulfuron methyl and foramsulfuron; mesosulfuron and iodosulfuron methyl; foramsulfuron and iodosulfuron-methyl; rimsulfuron and thifensulfuron rimsulfuron and nicosulfuron; bensulfuron-methyl and thifensulfuron-methyl; or thifensulfuron-methyl and chlorimuron-ethyl.

15. The composition according to any one of claims 1 to 13, comprising at least one sulfonylurea herbicide and at least one non-sulfonylurea herbicide, wherein the at least one sulfonylurea herbicide and the at least one non-sulfonylurea herbicide are selected from: tribenuron-methyl and 2,4-D; tribenuron-methyl and MCPB; tribenuron-methyl and bromoxynil; tribenuron-methyl and glyphosphate; tribenuron-methyl and fluroxypyr; tribenuron-methyl and dicamba; tribenuron-methyl and mecoprop-P; tribenuron-methyl and MCPA; tribenuron-methyl and clopyralid; tribenuron-methyl and carfentrazone ethyl tribenuron-methyl and clodinafop; tribenuron-methyl and quinclorac; tribenuron-methyl and florasulam; nicosulfuron and dicamba; nicosulfuron and atrazine; nicosulfuron and flumetsulam; nicosulfuron and clopyralid; nicosulfuron and diflupenzopyr; nicosulfuron and metolachlor; nicosulfuron and terbuthylazine; nicosulfuron and mesotrione; nicosulfuron and bentazone; metsulfuron methyl and acetochlor, metsulfuron methyl and carfentrazone ethyl; metsulfuron methyl and imazapyr; metsulfuron methyl and aminopyralid; metsulfuron methyl and fluroxypyr; metsulfuron methyl and mecoprop-p; metsulfuron methyl and picloram; metsulfuron methyl and pyraflufen ethyl; metsulfuron methyl and propanil; metsulfuron methyl and glyphosate-ammonium; metsulfuron methyl and dicamba; metsulfuron methyl and 2,4-D; bensulfuron-methyl and acetochlor, bensulfuron-methyl and butachlor; bensulfuron-methyl and daimuron; bensulfuron-methyl and mefenacet; bensulfuron-methyl and indanofan; bensulfuron-methyl and clomeprop; bensulfuron-methyl and pretilachlor; bensulfuron-methyl and fentrazamide; bensulfuron-methyl and thenylchlor; bensulfuron-methyl and pentoxazone; bensulfuron-methyl and pyriminobac-methyl; bensulfuron-methyl and bromobutide; triflusulfuron methyl and sulfentrazone; iodosulfuron-methyl and isoxadifen-ethyl; iodosulfuron-methyl and propoxycarbazone; iodosulfuron-methyl and diflufenican; iodosulfuron-methyl and fenoxaprop-P-ethyl; iodosulfuron-methyl and thiencarbazone-methyl mesosulfuron and diflufenican; mesosulfuron and propoxycarbazone; foramsulfuron and isoxadifen ethyl; foramsulfuron and thiencarbazone-methyl; foramsulfuron and cyprosulfamide; foramsulfuron and thiencarbazone-methyl; thifensulfuron-methyl and flumioxazin; chlorimuron-ethyl and acetochlor; chlorimuron-ethyl and flumioxazin; chlorimuron-ethyl and imazethapyr; chlorimuron-ethyl and metribuzin; chlorimuron-ethyl and sulfentrazone; pyrasulfuron-ethyl and pretilachlor; pyrasulfuron-ethyl and benzobicyclon; pyrasulfuron-ethyl and dimethametryn; rimsulfuron and mesotrione; rimsulfuron and metolachlor; and rimsulfuron and dicamba;

16. The composition according to any one of claims 1 to 15, wherein the sulfonyl urea exhibits at least 85% chemical stability when stored at 54° C. for two weeks relative to a control composition that has been stored at −10° C. for two weeks.

17. The composition according to claim 16, wherein the chemical stability of the sulfonyl urea is improved by at least 10% compared to a corresponding liquid composition that does not contain the at least one inorganic salt selected from the metal carbonates and metal phosphates.

18. The composition according to any one of claims 1 to 17, comprising metsulfuron-methyl (optionally as the sodium salt), fluroxypyr-meptyl, Na.sub.3PO.sub.4 and isobornyl acetate.

19. Use of an inorganic salt selected from the metal carbonates and metal phosphates to improve chemical stabilisation of a sulfonylurea herbicide in a liquid composition comprising a non-aqueous solvent system.

20. The use of an inorganic salt to improve chemical stabilisation of a sulfonylurea herbicide according to claim 19, wherein the inorganic salt is Na.sub.3PO.sub.4 and the sulfonyl urea is tribenuron-methyl, metsulfuron-methyl, nicosulfuron, bensulfuron-methyl, foramsulfuron, pyrazosulfuron-ethyl, chlorsulfuron, amidosulfuron, or triasulfuron; or the inorganic salt is Na.sub.2CO.sub.3, and the sulfonyl urea is tribenuron-methyl or nicosulfuron; or the inorganic salt is Mg.sub.3(PO.sub.4).sub.2 and the sulfonyl urea is rimsulfuron, bensulfuron-methyl, mesosulfuron-methyl, thifensulfuron-methyl, chlorimuron-ethyl, or triasulfuron; or the inorganic salt is AlPO.sub.4 and the sulfonyl urea is metsulfuron-methyl, halosulfuron-methyl or rimsulfuron.

Description

5. EXAMPLES

[0187] The oil dispersions described in the following examples were prepared as follows.

(i) Preparation of a 25 wt. % Sulfonylurea Millbase

[0188] Sulfonylurea was added to a solvent in an amount of 25 wt. %. The mixture was placed in a mill (Eiger Torrance Mini Mill) containing glass beads (1.0-1.25 mm). The suspension was then milled to provide a 25 wt. % sulfonylurea millbase having a particle size (D50) between 2 and 3 μm.

(ii) Preparation of a 30 wt. % Inorganic Salt Millbase

[0189] Inorganic salt (anhydrous) was added to solvent in an amount of 30 wt. % and milled as described above to provide a 30 wt. % inorganic salt millbase having a particle size (D50) between 2 and 3 μm. In some examples a polymeric dispersant, Atlox LP1, was included as a milling aid.

(iii) Preparation of the Oil Dispersion

[0190] An appropriate amount of the milled concentrate of sulfonylurea (i) was blended with solvent (optionally containing surfactant) until homogenous, and then further blended with milled concentrate of salt (ii) until homogenous, resulting in the oil dispersions as described in the tables below. For formulations containing an additional non-sulfonylurea co-herbicide, the additional herbicide was added as a second milled concentrate (if solid: e.g. terbuthylazine) or dissolved in the solvent/surfactant solution (if liquid: e.g. s-metolachlor).

[0191] Emulsifiable concentrates were prepared by blending the milled concentrate of sulfonylurea (i) with surfactant in a solvent and blending this with an appropriate amount of the milled concentrate of salt (ii).

[0192] The liquid formulations were stored in tightly closed glass bottles in thermostatically controlled incubators at 54° C. for two weeks with control samples stored at −10° C. After storage, all formulations were analysed for active ingredient content(s) by HPLC. Stability is reported with respect to the amount of active ingredient remaining relative to a corresponding sample stored at −10° C. for two weeks.

Example 1—Effect of Co-Formulated Inorganic Salt on SU Stabilisation

[0193] A number of oil dispersions comprising a metsulfuron-methyl (MSM) with or without an added salt were prepared and tested to determine the chemical stability of the sulfonylurea after storage at 54° C. for two weeks. The results are summarised in Table 1 below.

TABLE-US-00001 TABLE 1 Examples Comparative Examples Components (wt. %) OD1 OD2 OD3 OD4 OD5 OD6 OD7 OD8 OD9 OD10 OD77 OD11 MSM 5 5 5 5 5 5 5 5 5 5 5 5 Na.sub.3PO.sub.4 2.5 K.sub.3PO.sub.4 2.5 Na.sub.2CO.sub.3 2.5 AlPO.sub.4 2.5 Mg.sub.3(PO.sub.4).sub.2 2.5 Na.sub.2HPO.sub.4 2.5 Na.sub.2B.sub.4O.sub.7 2.5 Na.sub.3C.sub.6H.sub.5O.sub.7•2H.sub.2O 2.5 DIOSS 2.5 sodium lignosulfonate 2.5 urea 2.5 Atlox LP1 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Soprophor BSU 20 — 20 20 20 20 20 20 20 20 20 20 Isobornyl acetate to to to to to to to to to to to to 100 100 100 100 100 100 100 100 100 100 100 100 Stability (%) 97.5 93.9 84.0 86.5 86.8 84.4 69.0 82.0 81.0 83.7 43.5 83.3

[0194] The chemical stability of a sulfonylurea-containing oil dispersion comprising an inorganic salt selected from the metal carbonates and metal phosphates (OD1-OD6) was found to be superior to an oil dispersion with no co-formulated salt (OD11—similar to the teaching of US20060276337 A1) and oil dispersions using other salts (D7-OD10), including oil dispersions using DIOSS (sodium dioctyl sulfosuccinate) (OD9—similar to the teaching in US2006/0276337 A1) and sodium lignosulfonate (OD10—similar to the teaching of WO2007/027863 A2). Addition of urea (as taught by EP0554015 A1) increased chemical degradation of MSM (OD77). The chemical instability of metsulfuron-methyl has seriously limited its widespread use in liquid formulations. This problem is overcome by the present invention.

Example 2—Improved Stability of Different Sulfonylureas

[0195] A number of oil dispersions comprising different sulfonylurea compounds and different amounts of salt were prepared and tested to determine the chemical stability of the sulfonylurea after storage at 54° C. for two weeks. The results are summarised in Table 2 below.

TABLE-US-00002 TABLE 2 Examples Comparative Examples Components (wt. %) OD12 OD13 OD14 OD15 OD16 OD17 OD18 OD19 OD20 OD21 Nicosulfuron 5 5 Metsulforon methyl 5 5 5 Tribenuron-methyl 5 5 10 5 10 Na.sub.3PO.sub.4 2.5 2.5 10 5 10 10 Atlox LP1 0.02 0.02 0.08 0.04 0.08 0.08 Soprophor BSU 20 20 20 20 20 20 20 20 20 20 Isobornyl acetate to to to to to to to to to to 100 100 100 100 100 100 100 100 100 100 Stability (%) 99.4 97.5 99.6 91.7 93.5 96.5 86.7 83.3 0.4 29.7

[0196] Three sulfonylureas having comparatively high stability (nicosulfuron), medium stability (metsulfuron methyl) and low stability (tribenuron-methyl) were chosen for this example. The relative stability of the three chosen sulfonylureas is reflected in the stability data for OD18-OD21. If an inorganic salt selected from the metal carbonates and metal phosphates (OD12-OD17) is included in the oil dispersion, the chemical stability of the sulfonylurea can be greatly improved. The very low stability of sulfonylureas such as tribenuron-methyl has limited their widespread use in liquid compositions. This problem is overcome by the present invention.

Example 3—Sulfonylurea Salts are Also Stabilised

[0197] An oil dispersion of the sodium salt of tribenuron-methyl was prepared and tested to determine the chemical stability of the sulfonylurea after storage at 54° C. for two weeks. The results are summarised in Table 3 below.

TABLE-US-00003 TABLE 3 Comparative Examples Example OD22 OD23 OD24 Components (wt. %) Tribenuron-methyl sodium salt 2.95 2.94 3.09 Fluroxypyr-meptyl 24.15 24.12 24.69 Na.sub.3PO.sub.4 1.39 Na.sub.2CO.sub.3 1.38 Atlox LP1 0.05 0.05 Soprophor BSU 18.58 18.83 18.99 Isobornyl acetate to 100 to 100 to 100 SU Stability (%) 95 81 67

[0198] The data above demonstrates that a co-formulated inorganic salt selected from the metal carbonates and metal phosphates can stabilise a sulfonylurea salt in a liquid composition.

Example 4—Sulfonylureas and Co-Herbicides

[0199] Anumberofoildispersionscomprisingdifferentsulfonyluracompoundsanddifferentco-herbicide compounds (non-sulfonylureas) were prepared and tested. The results are summarised in Table 4 below.

TABLE-US-00004 TABLE 4 Examples Comparative Examples Components (wt. %) OD25 OD26 OD27 OD28 OD29 OD30 Metsulfuron-methyl 1 1 1 1 Nicosulfuron 1 1 s-metolachlor 32 32 terbuthylazine 25 25 fluroxypyr-meptyl 32 32 Na.sub.3PO.sub.4 0.5 0.5 0.5 Atlox LP1 0.004 0.004 0.004 Soprophor BSU 20 20 20 20 20 20 Isobornyl acetate to to to to to to 100 100 100 100 100 100 SU Stability (%) 89.8 86.5 82.0 22.7 9.7 34.6 Co-herbicide stability (%) 99.3 99.1 99.6 99.7 99.8 99.2

[0200] The addition of anon-sulfonylurea co-herbicide greatly reduces the stability of the sulfonylurea (OD28-OD30). However, the addition of an inorganic salt selected from the metal carbonates and metal phosphates (OD25-OD27) greatly improves the chemical stability of the sulfonylurea even in the presence of a co-herbicide. The present invention overcomes the problem and opens up the opportunity for a multiplicity of novel liquid formulations of sulfonylureas co-formulated with non-sulfonylurea herbicides.

Example 5-Effect of the Emulsifier on SU Stabilisation

[0201] A number of oil dispersions comprising metsulfuron-methyl (MSM) and trisodium phosphate with and without an emulsifier were prepared and tested. The results are summarised in Table 5 below.

TABLE-US-00005 TABLE 5 Examples Components (wt. %) OD31 OD32 OD33 OD34 OD35 OD36 MSM 5 5 5 5 5 5 Na.sub.3PO.sub.4 2.5 2.5 2.5 2.5 2.5 2.5 Soprophor BSU 20 Synperonic 91/6 20 Etocas 40 20 Sapogenat T080 20 Toximul 8320 20 Atlox LP1 0.02 0.02 0.02 0.02 0.02 0.02 Isobornyl acetate to to to to to to 100 100 100 100 100 100 Stability (%) 97.5 96.5 99.0 97.8 97.5 96.2

[0202] From the data in Table 5 it can be seen that the sulfonylura is stabilised by the inorganic salt irrespective of the emulsifier that is used (OD31-OD35) and also when no emulsifier is used (OD36; see also OD2). Contrary to the liquid compositions described in WO2008/155108 A2 and WO2009/152827 A2 which require very specific emulsifier systems, a sulfonylurea-containing liquid composition with co-formulated inorganic salt in accordance with the present invention is stable for a wide range of emulsifying systems.

Example 6—Effect of the Solvent on SU Stabilisation

[0203] A number of oil dispersions comprising metsulfuron-methyl (MSM) and a range of solvents with and without trisodium phosphate were prepared and tested. The results are summarised in Table 6-1 (with salt) and Table 6-2 (without salt) below.

TABLE-US-00006 TABLE 6-1 Examples Components (wt. %) OD37 OD38 OD39 OD40 OD41 OD42 MSM 5 5 5 5 5 5 Na.sub.3PO.sub.4 2.5 2.5 2.5 2.5 2.5 2.5 Synperonic 91/6 20 20 20 20 20 20 Atlox LP1 0.02 0.02 0.02 0.02 0.02 0.02 Solvesso 200ND to 100 sunflower oil to 100 Isopar M to 100 Exxsol D100 to 100 TEHP to 100 Radia 7961 to 100 Stability (%) 95.2 98.3 100 97.8 96.7 95.8

TABLE-US-00007 TABLE 6-2 Comparative Examples Components (wt. %) OD43 OD44 OD45 OD46 OD47 OD48 MSM 5 5 5 5 5 5 Na.sub.3PO.sub.4 Synperonic 91/6 20 20 20 20 20 20 Atlox LP1 Solvesso 200ND to 100 sunflower oil to 100 Isopar M to 100 Exxsol D100 to 100 TEHP to 100 Radia 7961 to 100 Stability (%) 71.3 90.8 92.3 92.9 82.1 89.8

[0204] It can be seen from the data in Table 6-1 that the sulfonylurea is stabilised by the inorganic salt irrespective of the solvent that is used. In the absence of the inorganic salt (Table 6-2), the stability of the sulfonylurea varies considerably with the choice of solvent. Contrary to the liquid compositions described in WO 2007/027863 A2 and WO2009/152827 A2 which require specific solvent systems, a sulfonylurea-containing liquid composition with co-formulated inorganic salt in accordance with the present invention is stable for a wide range of solvent systems.

Example 7—Emulsifiable Concentrate (EC)

[0205] An emulsifiable concentrate (EC) comprising metsulfuron-methyl dissolved in a non-aqueous solvent system was prepared with and without an added salt and tested. The results are summarised in Table 7 below.

TABLE-US-00008 TABLE 7 Comparative Example Example EC1 EC2 Components (wt. %) metsulfuron-methyl 5 5 Na.sub.3PO.sub.4 2.5 Soprophor BSU 20 20 Atlox LP1 0.02 Isobornyl acetate 20.83 23.33 n-butylpyrrolidone 51 65 51.67 Stability (%) 92.0 0

[0206] The data in Table 7 demonstrates that an inorganic salt selected from the metal carbonates and metal phosphates can stabilise a sulfonylurea in an emulsifiable concentrate (EC1). Importantly, stabilisation is even achieved in a solvent system comprising a pyrrolidone solvent as its major component, in the absence of the salt (EC2), such a solvent system causes complete degradation of the sulfonylurea in the accelerated ageing test (and as reported in U.S. Pat. No. 5,731,264). The present invention overcomes problems normally associated with pyrrolidone solvents in liquid compositions.

Example 8—Effect of the Solvent on SU Stabilisation in an Emulsifiable Concentrate (EC)

[0207] An emulsifiable concentrate (EC) comprising tribenuron-methyl dissolved in various non-aqueous solvent systems was prepared with and without an added salt and tested. The results are summarised in Table 8-1 (with salt) and Table 8-2 (without salt) below.

TABLE-US-00009 TABLE 8-1 Examples EC3 EC4 EC5 EC6 Components (wt. %) tribenuron-methyl 5 5 5 5 Na.sub.3PO.sub.4 5 5 5 5 Soprophor BSU 20 20 20 20 Atlox LP1 0.04 0.04 0.04 0.04 Isobornyl acetate 26.62 26.62 26.62 26.62 Rhodiasolv RDPE 43.34 Agnique AMD810 43.34 DMSO 43.34 n-butylpyrrolidone 43.34 Stability (%) 91.3 90.6 93.0 81.7

TABLE-US-00010 TABLE 8-2 Comparative Examples EC7 EC8 EC9 EC10 Components (wt. %) tribenuron-methyl 5 5 5 5 Na.sub.3PO.sub.4 — — — — Soprophor BSU 20 20 20 20 Atlox LP1 0.04 0.04 0.04 0.04 Isobornyl acetate 31.62 31.62 31.62 31.62 Rhodiasolv RDPE 43.34 Agnique AMD810 43.34 DMSO 43.34 n-butylpyrrolidone 43.34 Stability (%) 0 19.1 0 0

[0208] The data in Table 8-1 demonstrates that not only can an inorganic salt selected from the metal carbonates and metal phosphates stabilise a comparatively low-stable sulfonylurea in an emulsifiable concentrate, the sulfonylurea is stabilised in a wide range of solvent systems, including one comprising a pyrrolidone solvent.

Example 9—Improved Chemical Stability with Mg.SUB.3.(PO.SUB.4.).SUB.2 .or AlPO.SUB.4

[0209] A number of oil dispersions comprising different sulfonylurea compounds and Mg.sub.3(PO.sub.4).sub.2 or AlPO.sub.4 were prepared and tested in the same manner as for Example 1 (Atlox LP1 was not used). The results are summarised in Table 9 below.

TABLE-US-00011 TABLE 9 Examples Comparative Examples Components (wt. %) OD49 OD50 OD51 OD52 OD53 OD54 OD55 OD56 OD57 OD58 OD59 Rimsulfuron 5 5 5 Benzosulfuron-methyl 5 5 Mesosulfuron-methyl 5 5 Thifensulfuron-methyl 5 5 Chlorimuron-ethyl 5 5 Mg.sub.3(PO.sub.4).sub.2 5 5 5 5 5 AlPO.sub.4 5 Soprophor BSU 20 20 20 20 20 20 20 20 20 20 20 Isobornyl acetate to to to to to to to to to to to 100 100 100 100 100 100 100 100 100 100 100 Stability (%) 92.7 93.0 99.8 98.7 94.2 87.8 88.8 96.4 93.0 90.3 77.5

[0210] The data above shows that Mg.sub.3(PO.sub.4).sub.2 and AlPO.sub.4 can be used to improve the chemical stability of sulfonylurea herbicides in the above liquid compositions.

Example 10—Improved Chemical Stability of Different Sulfonylureas with Na.SUB.3.PO.SUB.4

[0211] A number of oil dispersions comprising different sulfonylurea compounds and Na.sub.3PO.sub.4 were prepared and tested in the same manner as for Example 1 (Atlox LP1 was not used). The results are summarised in Table 10 below.

TABLE-US-00012 TABLE 10 Examples Comparative Examples Components (wt. %) OD60 OD61 OD62 OD63 OD64 OD65 OD66 OD67 OD68 OD69 Benzosulfuron-methyl 5 5 Foramsulfuron 5 5 Pyrazosulfuron-ethyl 5 5 Chlorsulfuron 5 5 Triasulfuron 5 5 Na.sub.3PO.sub.4 5 5 5 5 5 Soprophor BSU 20 20 20 20 20 20 20 20 20 20 Isobornyl acetate to to to to to to to to to to 100 100 100 100 100 100 1001 100 100 100 Stability (%) 99.0 98.6 97.4 97.3 98.3 96.4 48.9 79.0 67.4 89.3

[0212] The data above shows that Na.sub.3PO.sub.4 can be used to improve the chemical stability of different sulfonylurea herbicides in the above liquid compositions.

Example 11—Urea as a Chemical Stabilizer for Nicosulfuron and Tribenuron-Methyl

[0213] EP 0554015 A1 (Ishiha Sangyo Kaisha) teaches that urea can be used to stabilise nicosulfuron (referred to as “Compound A” in that document). Oil dispersions comprising nicosulfuron were prepared and tested to determine the chemical stability of the sulfonylurea after storage at 60° C. for one week (same ageing test as used in EP0554015 A1). Stability is reported with respect to the amount of active ingredient remaining as determined by HPLC relative to a corresponding sample stored at −10° C. for one week. The results are summarised in Table 11 below.

TABLE-US-00013 TABLE 11-1 Examples Comparative Examples Components (wt. %) OD70 OD71 OD72 OD73 OD74 OD75 OD76 Nicosulfuron 4.91 4.91 4.91 4.91 Tribenuron-methyl 4.91 4.91 4.91 Na.sub.3PO.sub.4 2.50 Na.sub.2CO.sub.3 2.50 urea 2.50 1.05 3.00 Sorpol equiv.* 12.55 12.55 12.55 12.55 12.55 12.55 12.55 Bentonite 2.09 2.09 2.09 2.09 2.09 2.09 2.09 Maize oil to to to to to to to 100 100 100 100 100 100 100 Stability (%) 100.5 99.7 93.7 88.0 0 0 0 *Sorpol 3815K (which was used in EP 0554015 A1) was not readily available. Therefore, an estimated Sorpol equivalent made up of equal parts Synperonic 91/6, Aerosol OT-100, Croduret 25 and Atlas G1086 was used instead.

[0214] In OD73 (without any stabilizer) the decomposition rate of nicosulfuron was 12.0%. This improved to 6.3% on addition of 2.5 wt. % urea (OD72). Replacing urea with 2.5 wt. % Na.sub.3PO.sub.4 (OD70) or Na.sub.2CO.sub.3 (OD71) further improved the chemical stability of the nicosulfuron. Urea did not stabilise tribenuron-methyl to any degree in this system.

Example 12—Liquid Composition

[0215] A liquid composition comprising a sulfonyl urea in a non-aqueous solvent system (dimethyl sulfoxide) was prepared with and without an added salt and tested. The sulfonylurea was dissolved in the DMSO and the salt (milled) was dispersed as solid particles. The results are summarised in Table 12 below.

TABLE-US-00014 TABLE 12 Comparative Examples Example 12-1 12-2 12-3 Components (wt. %) tribenuron-methyl 5 5 5 Na.sub.3PO.sub.4 5 5 Soprophor BSU 10 20 10 DMSO 80 70 85 Stability (%) 97.1 96.4 0

[0216] The data in Table 12 demonstrates that an inorganic salt selected from the metal carbonates and metal phosphates can stabilise a typically unstable sulfonylurea (in this case tribenuron-methyl) in liquid compositions of the invention even if the sulfonylurea and salt are present in different phases.

[0217] The above description of the invention and included examples are intended to be illustrative and not limiting. All documents referred to herein are incorporated by reference. Various changes or modifications in the embodiments described herein may occur to those skilled in the art. These changes can be made without departing from the scope or spirit of the invention.