AQUEOUS FLOWABLE PHENAZAQUIN COMPOSITION

Abstract: The present invention relates to a novel aqueous flowable composition of phenazaquin. It was found that conventional aqueous flowable formulations resulted in a product that lost miticidal activity during storage. The low miticidal activity was found to be due to an unacceptable level of particle size growth during storage. It has been found that an aqueous flowable phenazaquin formulation of satisfactory particle size stability can be made when a higher than normal concentration of dispersant is utilized in the formulation.

Description: AQUEOUS FLOWABLE PHENAZAQUIN COMPOSITION Background of the Invention The present invention relates to an aqueous nowable composition for phenazaqui n Phenazaqum is the generic name for 4-[2-|4-(t-butyl)-ρhenyl]- ethoxylquinazo ne. It is representative of a new and usetυi class of miticidal compounds disclosed in EPO Application 89300657.7, filed January 2£ , 1989 An aqueous flowable composition, or simply, an aqueous flowable, is one type of agricultural formulation. An aqueous flowable is a formulation typically comprising an active ingredient which is a finely ground water-insoluble solid displaying good storage stability and is stable in the dispersing medium. The formulation will also typically include some or all of the followi ng: a surfactant, suspending agent, anticaking or flow aid, dispersant, defoamer, and freeze-point depressant, all of which are selected so that me formulation can be readily mixed in a liquid dispersing medium, such as water, or an anhyαro s organic soivem such as mineral oil, fatty oils, or glycol ethers, to form a stable suspension suitable tor spray application These formulations are made by standard techniques, well known in the art The surfactant acts as a wetting agent to reduce the surface tension at the water- solid interface, and therefore increases the tendency of the water to contact the complete surface of the active ingredient particles. Both anionic and/or nonionic surfactants may play a role in the stabilization of a flowable formulation. For a water-based flowable, the surfactant must be water sol uble, at least to the concentration limit desi red for the lower temperature limit. Examples of surfactants include anionic surfactants such as alkyl polyether alcohol sulfates, arylalkyl polyether alcohol sulfates, arylal kyl suhonates, alkyl napthalene sulfonates, and alkyl phenoxybenzene disulfonates, and nonionic surfactants, such as arylalkyl polyether alcohols, alkyl polyether alcohols, polyoxyethylene fatty acid esters, polyethylene sorbitan fatty acid esters, polyalkylene oxide block copolymers, polyalkylene oxide block copolymer monohydπc alcohols, and polyalkylene oxide block copolymer alkyl phenols Aqueous flowables typically contain 0.5- 10% by weight of a surfactant. The suspending agent acts as a thickening agent or thixotrope in maintaining the dispersed, micron sized particles of the formulation in suspension The suspending agent is a water soluble or water dispersible anionic colloid possessing shear thinni ng properties, low sensitivity to temperature, good stabi l ity in both acidic and basic media, and is compatible with most inorganic materials Examples of suspending agents include xanthan gums, organically modified montmoπllonite clays, attapulgite clays, carboxy-vinyl copolymers, and cellulose ethers Aqueous flowables typically contain 0 02- 1 % by weight of a suspending agent An anticaking agent or flow aid is a diluent which may be necessary to hel p improve the resuspensibility of the diluted spray, reduce the ultimate particle size of the active ingredient by acting as a grinding aid or lubricant i n the mi ll i ng process, modify the surface of the active ingredient thus inhibiting its crystal growth potential, and perform as a viscosity- modifying agent Examples of anticaking agents or flow aids include kao nite clays, diatomites, synthetic silicas, and attapulgites Aqueous flowables typically contain 0- 10% by weight of an anticaking agent or flow aid The dispersi ng agent is a polar organic material with surface active properties that orients itself between particles of active ingredient, and by virtue of size or charge, reduces the cohesiveness or attraction of the active ingredient particles for each other In addition to i mparting this physical stability to the aqueous mixture, dispersants may also aid in the redispersi bi ty of the diluted spray mixture The dispersing agent must be carefully selected and used to avoid problems such as foaming Examples of dispersants include the salts of the lignosulfonic acids, the polymerized alk yl arylalk y l or napthalene sul tonic salts, and high molecular weight anionic surfactants Aqueous flowable-> typically contain 0 1-2% by weight of a dispersi ng agent An antifoam agent, or defoamer, may be needed in the formulation if the surfactant or dispersant selected produces a stable foam when dil uted with water An antifoam agent may also be needed as a processing aid in milling to prevent aeration in the grinding stock dispersion because stable foamation during the milling process decreases the intimate contact between the grinding media and the active ingredient, thus decreasing grinding efficiency Example of defoamers i nclude the dimethyl polysi loxanes, Antifoam A, Antifoam C, Antifoam FG- 10, Antifoam DB- 100, and Anti foam AF 100 (Dow Corning) Aqueous flowables typical ly contain 0- 1 0% by weight of a defoamer A freeze-point depressant may be necessary to ensure good low temparature stability The more common examples of freeze-point depressants include ethylene and propylene glycol However, sorbitol and glycerol may also be typically used Functionally, in addition to lowering the freezing point of the water solvent, the freeze-point depressant may aid in preventing drying and skinning by acting as a humectant, controlling viscosity, removing hydrophobic impurities, and assisting the wetting process before and during milling Aqueous flowables typically contain 2- 10% by weight of a freeze-point depressant An antimicrobial agent may be necessary to prevent growth of bacteria, ungi, or other microbial organisms that can lourish in an aqueous environment Also, the poresence of xanthan gums, found in many aqueous flowable formulations, can accelerate the organism growth since tne gums can act as a food source for the microbial organism An example of an antimicrobial agent is Proxel GXL (1 ,2-benzιsothιazolιn-3-one, ICI) Aqueous flowables typically contain 0-0 2% of an antimicrobial agent To facilitate handling and use, agπchemicals are not typically sold in the form of pure active ingredient or technical material, but instead, are typically sold as a formulated composition product If the material is to be applied by spraying, it may typically be applied as an aqueous flowable In such case, the product obtained by the applicator is a formulated product that can be readily mixed with water to form an aqueous flowable product The product may then be applied from all types of presently used spray equipment Efforts to formulate phenazaquin as a conventional aqueous flowable formulation resulted in compositions of low miticidal activity It was found that conventional aqueous flowable formulations resulted i n a product that lost miticidal activity during storage The low miticidal activity was found to be due to an unacceptable level of particle size growth during storage Conventional aqueous flowable phenazaquin formulations were found to increase in particle size, apparently by crystal growth or Ostwald ripening, agglomeration, or by both The size of the particles is important as the miticidal efficacy of an aqueous flowable phenazaquin product depends upon the average particle size remaining less than seven microns, or preferably, less tnan four microns Description of the Invention Initial studies with early aqueous flowable tormulations of phenazaquin showed the propensity of phenazaqui n to grow in pan icle iize in an aqueous environment The solubility of phenazaquin in various formulation ingredients was determi ned based upon a classical Ostwald ripening effect Phenazaqui n was found to have little or no solubility (< 500 ppm) at 52°C in glycerin, lignosulfonate dispersants, silicone based wetti ng agents, ethylene oxide propylene oxide low molecular weight block copolymers, and other specific surfactants and dispersants These aqueous flowable formulations of phenazaquin, which should have shown no potential for crystal growth based on solubility, were evaluated However, crystal growth was observed Since dispersants at normal levels earl ier showed no effect on slowing down crystal growth a series of dispersants were ut ilized at excessive levels compared to normal use Quite surprisingly, one dispersant in particular, Morwet D-425 (sodi um napthalene formaldehyde condensate, DeSoto, Inc ), gave excellent results in slowing crystal growth to an acceptable level Accordingly, applicants have discovered an aqueous flowaϋle composition of phenazaquin that prevents the growth of phenazaquin particles to an average size greater than seven microns It has been unexpectedly found that a satisfactory aqueous flowable phenazaquin formulation can be made when a higher than normal concentration of dispersant is utilized i n the formulation This formulation may generally contain, by weight, (a) 10%-20% phenazaquin, (b) 0 5% - 10% one or more surfactants, (c) 0 02% - 1 0% one or more suspending agents, (d) 0% - 10 one or more anticaki ng or flow aids, (e) 5% - 1 5% one or more dispersants, (f) 0 1 %- 1 0% one or more defoaming agents, (g) 2% - 10% one or more freeze-point depressants, (h) 0 02-0.2% one or more antimicrobial agents, and (ι) 50% -85% water A preferred formulation may generally contain, by weight, (a) 15% -20% phenazaquin, (b) 0.5% -2% one or more surfactants, (c) 0.6%- 1 0% one or more suspending agents, (d) 6%- 12% one or more dispersants, (e) 0 1 %-0 5% one or more defoaming agents, (f) 4% -8% one or more freeze-point depressants, (g) 0.02-0 2% one or more antimicrobial agents, and (h) 60% -80% water. Preferred surfactants include Morwet EFW (sulfated alkyl carboxylate and sulfuonated alkyl napthalene sodium salt, DeSoto, Inc.), Pluronic P- 103 (ethylene oxide propylene oxide block copolymer, BASF), and Silwet L-77 (polyethoxysilane surfactant, Union Carbide) A preferred dispersant is Morwet D-425 Examples The following nonlimiting examples are provided to illustrate the invention described herei n Example 1 An aqueous flowable composition was prepared accordi ng to the following formulation and method Ingredient % weiqhuweiqht Phenazaquin 18 76 Morwet EFW 1 00 Morwet D-425 12 00 Antifoam AF- 100 0 40 Proxel GXL 0 05 (antimicrobial agent, ICi) Veegum 0 60 (Sι02 based, R T VanderDilt) Kelzan 0 1 5 (xanthan gum, Kelco) propylene glycol 8 00 water 59 04 Grind In a stainless steel beaker was combined 1775 gm water, 100 gm Morwet EFW, 200 gm Morwet D-425, and 20 gm Antifoam AF- 100, with stirring until uniform About one-half of this slurry was added to a Q 1 5 attritor and stirred for two to three minutes To the attritor was added 938 gm of phenazaquin and grinding continued for one hour Several times during the grind, about one pint from the bottom of the bl urry was taken and added back to the top After one hour tne grind was stopped and the gri nd solution was drained The remaining one-half of the slurry was added to the grind sol ution and the mixture was stired for two to three minutes The remaining 938 gm of phenazaquin was added to this mixture and the mixture and grinding was commenced for one hour Suspending slurry In a stainless steel beaker was combined 1700 gm of water, 5 gm of Proxel GXL, and 60 gm of Veegum with sti rring for about two to three minutes In a separate beaker was combined 800 gm of propylene glycol and 1 5 gm Kelzan with stirring This mixture was then slowly added to the above mixture of water, Proxel, and Veegum, and sheared with a dispersator for about 45 minutes Dispersant slurry In a four liter stainless steel beaker was combined 1000 gm of water and 20 gm of Antifoam AF- 100 To this mixture was slowly added 1000 gm of Morwet D-425 with stirring for about 30 minutes Recovery After the second one hour gri nd, the attritor was drained To the attritor was added about one-half of the dispersant sl urry with stirri ng for two to three minutes The attritor was again drained The remaining dispersant sl urry was added to the attritor with stiπng for two to three minutes and the attritor was agai n drained To the attritor was added 1429 gm of water with stirring for two to three minutes The attritor was again drained and a total of 7245 gm of grind rinse solution was recovered To the recovered solution was added 2519 1 gm of the suspending aid solution with stirring for about 30 minutes Particle analysis A Coulter Counter, Model TAII, which determines the number ana size distribution of panicles suspended in an electrolyte solution by measuring the change i n conductivity as particles pass through a small aperture in the counter device, was utilized as follows A 5- 10% mixture of the phenazaquin was prepared ι,ι the electrolyte solution, Isoton II (Couter), and then sonicated two to three minutes to assure complete dispersion of the particles A sample of this mixture was then diluted further in the electrolyte solution to about a 3% concentration This mixture was continuously stirred by the Coulter Counter device A stopcock located on the aperture tube of the device was then opened producing a vacuum inside the tube The reset button was then depressed which cleared the counter and applied current to the electrodes With the readout switch in the total coount position, the accumulate button was depressed and the count of the particles began and continued until the count reached 100,000- 150,000 Then, the stop button was depressed and the stopcock closed To obtai n the cumulative results, a sheet of Coulter graph paper was placed on the plotter, the readout switch was set to the % volume position, the scope display switch was set to cumulative plot, and the plot button was depressed To obtain the differential results, the display switch was set to differential plot and the plot button was again depressed The median particle size was obtained from the cumulative plot by measuring the particle size in microns at the 50% level Results Particle size analysis was conducted by the above method on samples of the above composition taken over a 15 week period at 37"C, room temperature (R T ), and 52°C The results obtained, in micronb (μ), were as follows 1.9 1 9 2 3 1 95 2 6 1 95 2 7 1 95 3 0 1 95 1 95 1 .9 (* "-" indicates no measurement was taken) Example 2 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation: Particle analysis and results. Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 3 week period at room temperature (R.T.) and 52°C. The results obtained, in microns (μ), were as follows: Initial 1 2 1 2 1 week 1 5 4 0 3 weeks large crystals which blocked aperature Example 3 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation- Ingredient Phenazaquin Pluronic P- 103 Proxel GXL Antifoam AF- 100 Reax 88B Veegum xanthan gum water Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 4 week period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows: Initial 1 2 1 2 1 week 1 4 3 4 4 weeks 5 4 Example 4 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation - Ingredient Phenazaquin Pluronic P- 103 Proxel GXL Antifoam AF- 100 Reax 88B V eegum xanthan gum Barden clay water Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the aoove composition taken over a 3 week period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows: 1 2 4 0 large crystals which blocked aperature Example 5 According to the general procedure disclosed i n Example 1 , above, an aqueous flowable composition was prepared according to the following formulation. Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 3 week period at room temperature (R T ) and 52"C The results obtained, in microns (μ), were as follows Initial 1 3 1 3 1 week 1 6 4 7 3 weeks 2 0 12 5 Example 6 According to the general procedure disclosed in Exampl 1 , above, an aqueous flowable composition was prepared according to the following formulation Ingredient Phenazaquin Pluronιc - 103 Proxel GXL Antifoam AF- 100 Reax 88B glycerin Veegum Kelzan water Particle analysis and resul ts Particle size analysis was conducted by the general method disclosedin Example 1 , above, on samples ot the aoove composition taken over a 1 month period at room temperature (R T ) and 52"C The results obtai ned, in microns (μ), were as follows T ime Initial 1 week 1 month Example 7 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared accordi ng to the following formulation Ingredient % weiqnuweiqht Phenazaquin 12 20 Morwet EFW 0 75 Lomar PWM 7 00 (al kyl napthalene sulfonate condensates, Henkel)) Proxel GXL 0 05 Antifoam AF-100 0 20 glyceri n 4 00 Veegum 0 75 Kelzan 0 25 water 74 80 Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples ot the above composition taken over a 1 month period at room temperature (R T ) and 52 ϋ C The results obtained, in microns (μ), were as follows. Initial 2 0 1 week - 6 3 1 month Example 8 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation: Ingredient % weight/weight Phenazaqui n 12 20 Morwet EFW 0 75 Dispersogen A 7 00 (alkyl napthalene sul fonate condensates, Hoechst) Proxel GXL 0 05 Antifoam AF- 100 0 20 glycerin 4 00 Veegum 0 75 Kelzan 0 25 water 74 80 Particle analysis and results Particle size analysis was conducted by the general o method disclosed in Example 1 above, on samples of the above composition taken over a 1 month period at room temperature (R T.) and 52 U C The results obtained, in microns (μ), were as follows: 5 Initial 4 2 1 week 1 1 0 1 month Example 9 0 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation : Ingredient 5 Phenazaquin Morwet EFW Reax 88B Proxel GXL Antifoam AF- 100 0 glycerin Veegum Kelzan water 5 Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 1 month period at room temperature (R T ) and 52"C The results obtained, i n microns (μ), were as follows Initial 2 65 1 week - 7 5 1 month Example 10 Accordi ng to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to tne fol lowing formulation Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 above, on samples of the above composition taken over a 1 month period at room temperature (R T ) and 52"C The results obtained, i n microns (μ), were as follows Initial 2 8 1 week - 7 4 1 month Example 1 1 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 1 month period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows: Initial 5 6 1 week - 9 0 1 month Example 12 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation: Inqredient Phenazaquin Morwet EFW Morwet D-425 Proxel GXL Antifoam AF-100 glycerin Veegum Kelzan water Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 1 month period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows Initial 2 1 1 week - 2 5 1 month - 2 6 Example 13 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation: Inqredient Phenazaquin Morwet EFW Morwet D-425 Proxel GXL Antifoam AF-100 glycerin Veegum Kelzan water Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 6 week period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows Initial 1 25 2 day 1 25 1 5 4 day - 1 5 1 week - 1 6 2 week 1 9 4 week 1 95 6 week 2 0 Example 14 According to the general procedure disclosed in Example 1 , above, an aqueous flowable composition was prepared according to the following formulation Inqredient % weight/weight Phenazaquin 12 20 Morwet EFW 0 75 Morwet D-425 5 00 Proxel GXL 0 05 Antifoam AF- 100 0 20 glycerin 4 00 Veegum 0 75 Kelzan 0 25 water 76 80 Particle analysis and results Particle size analysis was conducted by the general method disclosed in Example 1 , above, on samples of the above composition taken over a 1 week period at room temperature (R T ) and 52°C The results obtained, in microns (μ), were as follows 2 day 4 day 1 week Example 15 Bioassav Method Bioassays may be conducted on a variety of plant surfaces These consist of bountiful bushbean, squash cotyledons, apple, cotton, and orange Small seedlings are used and are trimmed to two leaves The leaves of bushbean are further trimmed to reduce the total surface area to one square inch in order to provide similar areas for each surface and to facilitate observation accuracy Acute activity is determined by premfesting each leaf 24 hours prior to treatment with 50 to 100 of a mixed population of twospotted spider mites (Tetranychus urticae) Plants are sprayed to wetting with the desired concentration and formulation using a Devilbiss atomizer Treatments are replicated four times and randomly distributed in a greenhouse for holding Mortality readings are taken 24 hours posttreatment by estimating the percent of morbid mites on each leaf through a dissecting microscope Residual activity is determined using the above procedure but infesting the seedling 24 hours posttreatment Ovicidal activity of the different formulations are compared by premfesting squash cotyledons with a mixed population containing 50 to 100 adult female twospotted spider mites Twenty-four hours after infestation, all mobile forms are removed by immersing the leaves for 90 seconds in 90% ethanol Plants are then rinsed with water and allowed to dry Data is analyzed using probit analysis Results Acute activity analysis was conducted by the above general method on samples of an aqueous flowable phenazaquin composition prepared according to Example 1 Rate is the concentration of active ingredient on a weight/weight basis in the spray solution expressed in parts per million (ppm) Mortality is the percent of morbid mites determined by the above methods The results obtained were as follows Samples of varying particle size and concentration of an aqueous flowable phenazaquin composition prepared according to Example 6 were analyzed according to the general bioassay method of Example 15 The results obtained were as follows: Size ikύ- 2.3 2.3 2.3 3.7 3.7 3.7 6.0 6.0 6.0 9.5 9.5 9.5 11.3 11.3 11.3 15.0 15.0 15.0

Claims: We claim : 1 An aqueous flowable composition comprising by % weight: (a) 10%-20% phenazaquin, (b) 0.5%- 10% one or more surfactants, (c) 0.02%- 1 0% one or more suspending agents, (d) 0%-10% one or more anticaking or flow aids, (e) 5% - 15% one or more dispersants, (f) 0 1 %- 1 0% one or more defoaming agents, (g) 2%-10% one or more freeze-point depressants, (h) 0.02-0 2% one or more antimicrobial agents, and (i) 50%-85% water 2 An aqueous flowable composition comprising by % weight: (a) 10%-20% phenazaquin, (b) 0.5%-2% one or more surfactants, (c) 0.6%-1 0% one or more suspending agents, (d) 6%- 12% one or more dispersants, (e) 0 1 %-0 5% one or more defoaming agents, (f) 4% -8% one or more freeze-point depressants, (g) 0.02-0 2% one or more antimicrobial agents, and (h) 50%-80% water 3 A composition of claim 2 wherein the surfactant is Morwet EFW. 4 A composition of claim 2 wherein the dispersant is Morwet D-425, Pluronic P- , or Silwet L-77. 5 A composition of claim 4 wherein the dispersant is Morwet D-425. 6 An aqueous flowable composition comprising by % weight: (a) 15%-20% Phenazaquin, (b) 0.5 -2% Morwet EFW, (c) 6%- 12% Morwet D-425, (d) 0.1-0.5% Antifoam AF- 100, (e) 0.02%-0 08% Proxel GXL, (f) 0.50%-0 70% Veegum, (g) 0 1 % -0 2% Kelzan, (h) 4%-8% Propylene Glycol, and (i) 50%-80% water 7 A method of inhibiting a mite which comprises applying to a locus of the mite a composition of claim 1 8 A method of inhibiting a mite which comprises applying to a locus of the mite a composition of claim 6

Inventors: ROWLAND LARRY B, WINKLE JOSEPH R, ROWLAND, LARRY, B., WINKLE, JOSEPH, R.
Applicants: DOWELANCO
Application year: 1993
Main classification: A01N43
IPC codes: A01N25, A01N43, A01P7