CA2911971C - Clopyralid aqueous concentrate composition - Google Patents

Abstract

The invention relates to controlling the viscosity of high loadings of aqueous concentrate composition of the herbicide clopyralid which contain clopyralid in the form of the triisopropanolamine (TI PA) salt and the clopyralid concentration of at least 350 gae/L is obtained using a pH, measured at 20 C, of 2.5 to 5.5 and a molar ratio of TI PA to clopyralid of 0.4:1 to 1:1.

Description

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Clopyralid Aqueous Concentrate Composition [0001] This invention relates to an aqueous concentrate composition comprising the herbicide clopyralid in the form of the triisopropanolamine (TIPA) salt and to methods for the preparation and use of such compositions in the control of weeds.

[0002] Clopyralid (3,6 ¨ dichloro-2-pyridinecarboxylic acid) is a selective post-emergence group I herbicide which may be used to control broad-leaved weeds in crops such as beet, canola, triticale, maize, cereals, brassica, onions, leek, strawberries and flax. Clopyralid has also been used in pastures, fallow land, forests and in industrial situations. Clopyralid is of low toxicity to fish, aquatic invertebrate animals, birds, mammals and bees. Salts of clopyralid are more soluble in water than the acid form, and clopyralid is frequently provided for consumer use as a neutralised aqueous concentrate in which the clopyralid acid is neutralised by a base such as an amine or alkali metal base.

[0003] Clopyralid has been sold under the brand names LONTREL, STINGER, CONFRONT, RECLAIM, CUR-TAIL, and TRANSLINE. Clopyralid salt formulations have been made based on neutralisation with amines such as dimethylamine, triethylamine salt, triisoproplyamine, monoethanolamine, triethanolamine, triisopropanolamine (TIPA) or alkali metal bases such as potassium hydroxide.

[0004] The TIPA salt of clopyralid has been used in many commercially available clopyralid formulations. Triisopropanolamine is a solid making it easier to handle and use in the manufacture of herbicidal amine salts than gaseous low molecular weight amines or volatile liquids. Concentrate compositions of TIPA clopyralid salt are generally of concentration no more than 300 grams acid equivalent per litre (gae/L).
Examples of commercially available clopyralid TIPA salt concentrates include INNOVATM Clopyralid 300 Herbicide (300 gae/L TIPA salt by Syngenta Crop Protection); TITANTM clopyralid 300 Herbicide (300 gae/L TIPA salt by Titan);
GENERIXTM Clopyralid (300 g/L TIPA salt by Macspred; LONTREL clopyralid (300 g/L TIPA salt by Dow AgroSciences); and APPARENTTm 300 clopyralid (300 gae/L
TIPA salt by Apparent Pty Ltd). These formulations have an undiluted pH in the range 6 ¨ 8.

[0005] Clopyralid TIPA salt aqueous concentrates have not previously been available at concentrations greater than about 300 gram acid equivalent per litre (gae/L).

[0006] It is desirable to provide more highly concentrated aqueous concentrates of clopyralid to reduce the weight that needs to be delivered and managed by the user in preparing the diluted compositions prior to application. More highly concentrated compositions provide consequential savings on transport from factory to point of use, packaging materials and recycling of the packaging materials.

[0007] Commercially available higher loadings of clopyralid in liquid concentrates have been obtained by using salts other than TIPA salt. For example Buttimor (US
Publ. No. 2011/0230349 "High-Strength, Low-Viscosity Herbicidal Concentrate of Clopyralid Dimethylamine", filed March 2011) refers to the sale by Dow AgroSciences of LONTRELTm 300 gae/L clopyralid TIPA salt concentrate and LONTRELTm 360 gae/L, clopyralid monoethanolamine salt concentrate and recognises the importance of achieving higher loadings of clopyralid. In order to produce higher loadings Buttimor teaches the use of a high-strength (450 ¨ 850 gae/L) aqueous clopyralid formulation of low viscosity based on neutralisation of the clopyralid with dimethylamine. Buttimor compares the efficacy of the 630 gae/L dimethylamine salt concentrate with a commercial 300 gae/L clopyralid TIPA salt concentrate across all application rates examined and asserts that the dimethylamine concentrate showed nearly equivalent performance to the commercial TIPA composition. The nature of the neutralising base used to provide the clopyralid salt in a clopyralid concentrate is an important feature of the formulation.

[0008] Triisopropanolamine is relatively non-flammable amine which is solid at room temperature and is safer to handle on an industrial scale than lower molecular weight amines in the form of gases or volatile solutions. It is also safer for the end user due to reduced volatility and spill hazard. It is desirable to provide a high-strength clopyralid formulation comprising the TIPA salt.

[0009] The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters =

Canadian Application No. 2,911,971 formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

[0010] Throughout the description and the claims of this specification the word "comprise" and variations of the word, such as "comprising" and "comprises" is not intended to exclude other additives, components, integers or steps.
Summary

[0011] There is provided an aqueous concentrate of clopyralid comprising clopyralid in the form of the triisopropanolamine (TIPA) salt and a clopyralid concentration of at least 350 gae/L and wherein the pH of the composition measured at 20 C is in the range of 2.5 to less than 6 (preferably 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5). In a preferred set of embodiments the mole ratio of TIPA to clopyralid is in the range of 0.40:1 to 1:1, still more preferably from 0.4:1 to 0.65:1.

[0012] Whereas prior art aqueous formulations of clopyralid TIPA salt have been substantially neutralised to a pH in the range 6 ¨ 8 we have found that formulation of the concentrate at a lower pH allows much higher loadings at useful viscosities than have previously been recorded for the TIPA salt of clopyralid. Without wishing to be bound by theory we believe that, while clopyralid acid is relatively poorly soluble in water the presence of a mixture of clopyralid acid and clopyralid TIPA salts at such a pH allows a lower viscosity to be obtained at high concentration of clopyralid than is possible at higher pH.
Detailed Description

[0013] In a further embodiment there is provided a method for preparation of an aqueous concentrate comprising clopyralid TIPA salt comprising combining TIPA
and clopyralid acid in an aqueous liquor and when the resulting pH is six or more adding acid to provide a pH in the range of from 2.5 to less than 6 (preferably 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5).
Preferably the pH is brought into the range of 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5) by the combination of clopyralid and TIPA or is adjusted by the addition of acid to fall into this range. The process may involve addition 7684647.1 Canadian Application No. 2,911,971 (preferably with mixing) of base comprising TIPA to clopyralid acid (preferably an aqueous slurry of clopyralid acid) or the addition clopyralid acid to the base (preferably an aqueous solution of base) comprising TIPA. It is preferred to add clopyralid acid to an aqueous solution of the base comprising TIPA with mixing.

[0014] In one embodiment of the method clopyralid acid is added to and mixed with an aqueous solution of base comprising TIPA in an amount to provide a pH
in the range of from 2.5 to less than 6 (preferably 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5). In another embodiment clopyralid is added to an aqueous solution of base comprising TIPA in an amount less than required to reduce the pH to within the range of from 2.5 to less than 6 (preferably 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5) and an acid other than clopyralid such as a mineral or organic acid, is added to provide the pH in the range of from 2.5 to less than 6 (preferably 2.5 to 5.5, more preferably in the range 3 to 5 and still more preferably 3 to 4.5). The base comprising TIPA may further comprise other bases such as amionia, primary alkylamine, primary alkanolamine, dialkylamine, dialkanolamine, dialkylalkanolamine, trialkylamine, trialkanolamine (other than triisopropanolamine salt) and alkali metals bases such as sodium hydroxide or potassium hydroxide. The alkan or alkyl portion of the above mentioned alkylamines and alkanolamines is preferably a Ci to C4 amine which, when there are more than one alkan/alkyl group, may be independently selected. When additional bases are present it is preferred that the TIPA is present in an amount of at least 30 mol% preferably at least 45 mol% of the bases, preferably at least 60 mol%, more preferably at least 80 mol% such as at least 90 mol% or at least 95 mol%.

[0015] It is preferred that the mole ratio of TIPA to clopyralid is in the range of from 0.40:1 to 1:1, more preferably 0.40:1 to 0.65:1.

[0016] The concentrate composition preferably comprises at least 400 gae/L
clopyralid, more preferably at least 450 gae/L clopyralid, still more preferably at least 500gae/L clopyralid, still more preferably at least 550 gae/L such as at least gae/L clopyralid. Generally the concentrate will have a clopyralid concentration of no more than 800 gae/L such as no more than 750 gae/L. Compositions in the range of from 500 gae clopyralid per litre to 650 gae clopyralid per litre are particularly preferred.
7684647.1

[0017] The composition in one set of embodiments comprises clopyralid in the form the TIPA salt in a concentration of at least 350 gae/L preferably at least 400 gae/L clopyralid, more preferably at least 450 gae/L clopyralid, still more preferably at least 500 gae/L clopyralid, still more preferably at least 550 gae/L such as at least 600 gae/L clopyralid.

[0018] The composition may, in one set of embodiments, comprise clopyralid salts other than TIPA. For example, the concentrate composition may contain a proportion of salts of clopyralid other than TIPA salts. Examples of optional salts may be selected from the group of amionia salt, primary alkylamine salt, primary alkanolamine salt, dialkylamine salt, dialkanolamine salt, dialkylalkanolamine salt, trialkylamine salt, trialkanolamine salt (other than triisopropanolamine salt) and alkali metals such as potassium. The alkan or alkyl portion of the above mentioned alkylamines and alkanolamines is preferably a C1 to C4 amine which, when there are more than one alkan/alkyl group, may be independently selected. When additional salts are present it is preferred that the TIPA is present in an amount of at least 30 mol%
preferably at least 45 mol% of the counter ions, preferably at least 60 mol %, more preferably at least 80 mol% such as at least 90 mol % or at least 95 mol %.

[0019] In order to obtain very high loading of, for example, at least 450 gae/L, preferably at least 500 gae/L and more preferably at least 550 gae/L, with comparatively low viscosity, we have found that it is an advantage to use a molar ratio of TIPA:clopyralid of less than 0.9:1. The preferred ratio in order to minimise viscosity is in the range 0.4:1 to 0.8:1, more preferably 0.4:1 to 0.65:1 and the optimum is generally in the range of from 0.45:1 to 0.55:1. The amount of water present in the concentrate will depend on the required concentration of clopyralid.

[0020] In this embodiment, other amines selected from primary, secondary and tertiary amines will constitute less than 20 mol% and more preferably less than 10 mol% and most preferably less than 5 mol%, based on the number of moles of clopyralid.

[0021] The composition will comprise water as part of the aqueous concentrate composition. The water is predominant carrier and the clopyralid is generally present as a solution concentrate in the aqueous carrier. In the case of highly concentrated compositions the added water is preferably present in an amount in the range of from 300g to 400g water per litre of concentrate and more preferably in the range of form 320g to 360g water per litre of concentrate. Accordingly in one embodiment the composition comprises from 550 to 700 gae/L of clopyralid, TIPA in a molar ratio of TIPA:clopyralid in the range of 0.4:1 ¨ 0.65:1 (preferably 0.45:1 to 0.55:1) an amount of water of from 140 g/L to 400g/L (preferably 300g/L to 400 g/L, more preferably 320g/L to 360g/L) and a pH in the range of from 3 to 5 (preferably 3 to 4.5).

[0022] The aqueous clopyralid TIPA salt concentrate generally has a viscosity of no more than 2000 cps at 20 C and preferably no more than 1000 cps at 20 C and still more preferably no more than 500 cps at 20 C. The viscosity referred to is Brookfield viscosity determined using a No. 2 spindle at 20 r.p.m. The viscosity at C is preferably no more than 4000 cps, more preferably no more than 2000 cps.

[0023] The concentrate can be applied to plants in an amount sufficient to induce an herbicidal effect. For example, a concentrate prepared according to the present invention can be applied as a diluted aqueous solution to plants including the plants' leaves, stems, branches, flowers and/or fruit. The herbicidal formulation can be applied in an herbicidally effective amount sufficient to inhibit plant growth or kill individual plants.

[0024] The concentrate of the present invention may also be mixed with or applied with other herbicides. Suitable herbicides which may be mixed with or applied with the composition of the present invention to control plant growth include, but are not limited to, 2,4-D esters and amines, acetochlor, aclonifen, amidosulfuron, am inocyclopyrachlor, am inopyralid, aminotriazole, ammonium thiocyanate, asulam, atrazine, beflubutamid, benazolin, bentazone, bifenox, bromacil, bromoxynil, butachlor, butafenacil, butralin, butroxydim, carbetamide, carfentrazone, carfentrazone-ethyl, chlormequat, chlorsulfuron, chlortoluron, cinidon-ethyl, clethodim, clodinafop-propargyl, clomazone, cyanazine, cyclosulfamuron, cycloxydim, dicamba, dichlobenil, dichlorprop-P, diclofop-methyl, diflufenican, diflufenzopyr, dimefuron, dimethachlor, diquat, diuron, EPTC, ET-751, ethoxysulfuron, fenoxaprop, fenoxaprop-ethyl, fenoxaprop-ethyl + isoxidifen-ethyl, fenoxaprop-p-ethyl, flazasulfuron, florasulam, fluazifop, fluazifop-P -butyl, flucarbazone, flucetosulfuron (LGC-42153), flufenacet, flumetsulam, flumioxacin, flupyrsulfuron, fluroxypyr, fluroxypyr meptyl, flurtamone, glufosinate, glufosinate-ammonium, glyphosate, haloxyfop-methyl, haloxyfop-R, hexazinone, imazamethabenz, imazamox, imazapic, imazapyr, imazaquin, imazethapyr, imazosulfuron, indanofan, iodosulfuron, iodosulfuron-ethyl-sodium, ioxynil, isoproturon, isoxaben, isoxaflutole, KIH-845, lactofen, linuron, MCPA, mecoprop-P, mesosulfuron, mesosulfuron-ethyl sodium, metazochlor, metosulam, metribuzin, metsulfuron, metsulfuron- methyl, MSMA, napropamide, norfurazon, orthosulfamuron, oryzalin, oxadiargyl, oxadiazon, oxyfluorfen, paraquat, pendimethalin, penoxsulam, picloram, picolinafen, pinoxaden, prim isulfuron, profluazol, propaquizafop, propoxycarbazone, propyzamide, prosulfocarb, prosulfuron, pyraflufen ethyl, pyrasulfotole, pyribenzoxim (LGC-40863), pyroxsulam, quinmerac, quizalofop-ethyl-D, quizalofop-P-ethyl, quizalofop-p-tefuryl, sethoxydim, simazine, sulfentrazone, sulfosate, sulfosulfuron, tebuthiuron, tepraloxidim, terbacil, terbutryn, thiazopyr, thifensulfuron, thifensulfuron-methyl, topramezone, tralkoxydim, triasulfuron, tribenuron, tribenuron-methyl, triclopyr and trifluralin.

[0025] The surfactants may, if desired, be used in the concentrate compositions of the present invention can be anionic, cationic or nonionic in character.
Surfactants conventionally used in the art of formulation and which may also be used in the present formulations are described, inter alia, in "McCutcheon's Detergents and Emulsifiers Annual", MC Publishing Corp., Ridgewood, N.J., 1998 and in "Encyclopedia of Surfactants", Vol. I-III, Chemical publishing Co., New York, 1980-81.
Typical surfactants include salts of alkyl sulfates, such as diethanolammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium dodecylbenzenesulfonate;
alkyl and/or arylalkylphenol-alkylene oxide addition products, such as nonylphenol-ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol-ethoxylate; soaps, such as sodium stearate; alkylnaphthalenesulfonate salts, such as sodium dibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate; sorbitol esters, such as sorbitol oleate;
quaternary amines, such as lauryl trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; salts of mono and dialkyl phosphate esters; and mixtures thereof. The surfactant or mixture of surfactants may, in one set of embodiments, be present at a concentration of from about 0% to 10% by weight and preferably from 0% to 5% by weight of the concentrate composition. In a more preferred set of embodiments the composition comprises no more than 1% by weight of surfactants.

[0026] The herbicidal compositions prepared according to the present invention are highly effective against a variety of weeds. The concentrate of the present invention can be used as is or combined with other components including other agriculturally acceptable adjuvants commonly used in formulated agricultural products, such as antifoam agents, compatibilizing agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, penetration aids, wetting agents, spreading agents, dispersing agents, thickening agents, freeze point depressants, antimicrobial agents, crop oil, safeners and the like. The concentrated agricultural formulations are typically diluted in water and then applied by conventional means well known to those skilled in the art.

[0027] In a further set of embodiments there is provided a method of controlling weeds comprising applying to weeds, or the locus of required weed control, a composition as hereinbefore described.

[0028] The composition is particularly suitable for control of broadleaf weeds such as thistles and clovers. The composition may be used in control of weeds in crops by pre-emergent application or post-emergent application to weeds. The composition may be used in controlling weeds in crops such as barley, oats, triticale and weed by pre-sowing application, post-sowing pre-emergent application, early post-emergent application or subsequent application.

[0029] The invention will now be described with reference to the following examples. It is to be understood that the examples are provided by way of illustration of the invention and that they are in no way limiting to the scope of the invention.
EXAMPLES

[0030] Example 1: Formulation matrix showing various clopyralid loadings, various pH values and various mole ratios of TIPA to clopyralid.

[0031] Clopyralid has a mole weight of 192, and a pKa of 2.3. TIPA has a mole weight of 191.

[0032] The compositions in Table 1 were each prepared by the following procedure:
Step 1 Dissolve TIPA in the specified amount in water with constant agitation.
Step 2 Slowly add Clopyralid acid (technical) in the specified amount to the composition and continue mixing until dissolved.

[0033] The pH of the composition was measured using the standard procedure of the Collaborative International Pesticides Analytical Council (CIPAC) MT 75.
The viscosity reported at 20 C and 5 C is a Brookfield viscosity measured using spindle No. 2 at 20 r.p.m.
Table 1 No. Clopyralid TIPA water density pH at pH at Visc at Visc Mol ratio 97% 99% g/L 5 C 20 C 20 C at 5 C TIPA/Clo g/L g/L g/L (cP) (cP) CE1 309.28 314.3 645.2 1268.7 3.2 2.8 low low 1.04 CE2 309.28 340.2 631.0 1289.2 3.6 3.0 low low 1.13 CE3 309.28 350.1 573.9 1234.1 3.6 3.5 low 39.3 1.16 CE4 309.28 352 514 1175.3 4.4 4 low 85.8 1.17 CE5 309.28 356 511 1176.3 5.4 5 low 89.1 1.18 CE6 309.28 372.7 500 1182.2 6.8 6 low 89.1 1.24 CE7 309.28 385.6 505.3 1200.2 7.4 7 low 90.2 1.28 CE8 309.28 454.5 438.2 1202.0 8.4 8 low 118.5 1.51 E9 412.4 381 386.5 1179.9 3.3 3.0 33.1 125 0.95 El 0 412.4 401.3 370.1 1184.6 3.6 3.5 46.2 130.1 1.00 Ell 412.4 430.2 355.7 1198.3 4.3 4.0 58.2 139.2 1.07 CE12 412.4 467.8 326.9 1207.1 5.6 5.0 65.1 235 1.16 CE13 412.4 484.3 256.6 1153.3 6.7 6.0 91.8 642 1.20 CE14 412.4 506.7 238.5 1157.6 7.3 7.0 111.9 2695 1.26 CE15 412.4 651.5 144.6 1208.5 8.5 8.0 732 3630 1.62 El6 515.46 392.7 286.3 1194.5 3.4 3.0 130 409 0.78 E17 515.46 449.4 275.1 1239.9 4.3 4.0 94.5 456 0.89 El 8 515.46 524.3 162.7 1202.5 4.4 4.2 171 963 1.04 E19 515.46 549.9 160.4 1225.7 5.1 5.0 552 1386 1.09 CE20 515.46 608 151.1 1274.6 6.9 6.3 762 1686 1.21 CE21 515.46 615.9 146.0 1277.3 7.4 7 1435 Cannot 1.22 measure CE22 515.46 660.8 56.3 1232.6 8.1 8.0 3825 Cannot 1.31 measure E23 618.6 320.9 340.8 1280.3 3.4 3.2 360 1920 0.53 E24 618.6 526.8 160.3 1306.7 3.7 3.6 792 6450 0.87 E ¨ Examples of the Invention CE ¨ Comparative Examples not of the invention.

[0034] Note: Surfactants and other agriculturally approved additives (e.g. to minimise spray drift) may be added, and tank mixes of the clopyralid formulation of the invention may be used with other herbicides or other agents that protect the target crop.

[0035] Example 2:
MATERIALS AND METHODS

[0036] This example compares the efficacy of the composition of E23 referred to in Table 1 having a clopyralid concentration of 600 gae/L (referred to as Clopyralid 600 TIPA) with a commercial formulation "Apparent 300" containing clopyralid as theTIPA salt in a concentration of 300 gae/L and "Apparent 750 SG" containing clopyralid as the potassium salt in a concentration of 750 gae/Kg.
Plant propagation

[0037] Lentil (cv Nugget) was sown in 10cm diameter pots filled with potting mix (AS 3743). One week after seedling emergence, seedlings were thinned for uniform size to one seedling per pot. Seedlings were germinated in a temperature-controlled greenhouse (14 C ¨ 25 C) for 6 days then grown outdoors for 9days prior to spray application, to more closely simulate field conditions. After the application of herbicides the pots were returned to the greenhouse until harvested for fresh weight.
Herbicide application

[0038] Herbicide formulations were applied using an enclosed laboratory track-sprayer fitted with a 1100 flat fan nozzle (Teejet XR11001-VS), at a pressure of 200 kPa applying a spray volume of 64L/ha.

Assessments

[0039] Visual observations of % control were recorded 7DAT. Seedlings were harvested by cutting foliage off at base immediately prior to weighing on a Sartorius Basic electronic balance (range 0-4100 g) 13DAT.
Statistical analyses Factorial Analysis of Variance

[0040] Data was analysed using a factorial design with two factors, Formulation and Rate. 5% least significant differences (LSD) were calculated for the mean of each treatment. The greatest herbicidal effect is denoted with alpha code "a"
when significantly different to other treatments, which are coded "b", "c", "d"
etc. with decreasing herbicidal effect.
RESULTS - % CONTROL 7DAT
Factorial Analysis of Variance

[0041] There were highly significant effects for formulation and rate and no significant interaction between the two factors (Table 2).
Table 2 FAOV table ¨ 7DAT
FPr LSD (P=0.05) Formulation 0.0001 4.0 Rate 0.0001 4.7 Formulation x Rate 0.06 7.7 Formulation

[0042] There was no significant difference between Clopyralid 600 TIPA and Apparent 750 SG and no significant difference between Apparent 300 and Apparent 750 SG.

Table 3 FAOV table & significant differences - % control 7DAT
Rate (g ai/ha) Formulation Mean 9.375 18.75 37.5 75 *Clopyralid 600 TIPA 36 g 1 51 ef 69 ab 76 a 58 b Apparent 300 (TIPA) 36 g 47 f 59 cde 67 bc 52 c Apparent 750 SG (Potassium) 36 g 57 de 57 de 66 bc 54 bc Rate mean 38 d 55 c 63 b 71 a = The Clopyralid 600 TIPA in accordance with the invention corresponded with Example "E23" of Table 1 Rate

[0043] Averaged across formulations, all rates were significantly different (Table 3).
RESULTS ¨ FRESH WEIGHT 13DAT
Factorial Analysis of Variance

[0044] There was no significant formulation effect; a highly significant rate effect and no significant interaction between the two factors (Table 4).
Table 4 FAOV table ¨ 13DAT
FPr LSD (P=0.05) Formulation 0.16 NS
Rate 0.0001 0.08 Formulation x Rate 0.07 0.18 Formulation

[0045] Averaged across rates, there was no significant difference between formulations (Table 5).

Table 5 FAOV table & significant differences ¨ Fresh weight (g) 13DAT
Rate (g al/ha) Formulation Mean 9.375 18.75 37.5 75 UTC 0.85 Clopyralid 600 TIPA 0.59 c 0.42 bc 0.15 a 0.10 a 0.32 Apparent 300 (TIPA) 0.58 c 0.42 bc 0.23 a 0.16 a 0.35 Apparent 750 SG (potassium) 0.79 d 0.22 a 0.25 ab 0.14 a 0.35 Rate mean 0.62 d 0.32 c 0.21 b 0.12 a Rate

[0046] Averaged across formulations, all rates were significantly different (Table 5).

Claims (16)

Canadian Application No. 2,911,971 CPST Ref: 102720/000003 1 4

1 . An aqueous concentrate composition of clopyralid comprising clopyralid in the form of the triisopropanolamine (TIPA) salt and a clopyralid concentration of at least 350 gae/L and wherein the pH of the composition measured at 20 C is in the range of 2.5 to 5.5 and the molar ratio of TIPA to clopyralid is 0.4:1 to 1:1.

2. The aqueous concentrate composition of clopyralid according to claim 1, wherein the pH of the composition measured at 20 C is in the range of 3 to 5.

3. The aqueous concentrate composition of clopyralid according to claim 1 or 2 comprising at least 450 gae/L clopyralid.

4. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 3, wherein the composition comprises at least 550 gae/L
clopyralid.

5. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 4, wherein the molar ratio of TIPA to clopyralid is in the range of from 0.4:1 to 0.9:1.

6. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 4, wherein the molar ratio of TIPA to clopyralid is in the range of from 0.4:1 to 0.65:1.

7. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 6, wherein the clopyralid concentration is no more than 750 gae/L.

8. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 7, wherein the concentrate has a viscosity of no more than 800 cps at 20 C.

9. The aqueous concentrate composition of clopyralid according to any one of claims 1 to 8, wherein water is present in the concentrate in an amount in the range of from 300 - 400 g water per litre of concentrate.
CPST Doc: 322829.1 Date Reçue/Date Received 2020-12-14 Canadian Application No. 2,911,971 CPST Ref: 102720/000003

10. A method for preparation of an aqueous composition of clopyralid TIPA
salt comprising mixing an aqueous base comprising TIPA with clopyralid acid in an aqueous liquor and when the resulting pH is six or more adding acid to provide a pH in the range of from 2.5 to 5.5, wherein the molar ratio of TIPA to clopyralid is 0.4:1 to 1:1.

11. A method according to claim 10 wherein the base comprising TIPA is in an amount to provide a pH in the range of from 2.5 to 5.5.

12. A method according to claim 10 or claim 11 wherein the base comprising TIPA
is in an amount to provide a pH in the range of from 3 to 5.

13. A method according to any one of claims 10 to 12 wherein the mole ratio of TIPA to clopyralid is in the range of from 0.4:1 to 0.9:1.

14. A method according to any one of claims 10 to 13 wherein the mole ratio of TIPA to clopyralid is in the range of from 0.4:1 to 0.65:1.

15. A method according to any one of claims 10 to 14 wherein the mole ratio of TIPA to clopyralid is in the range of from 0.45:1 to 0.55:1.

16. A method according to any one of claims 10 to 15, wherein in the range of from 300 g to 400 g water is present per litre of the resulting composition.
CPST Doc: 322829.1 Date Reçue/Date Received 2020-12-14