CA1195923A - Cold stabilization of aqueous herbicidal compositions with urea - Google Patents
Cold stabilization of aqueous herbicidal compositions with ureaInfo
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- CA1195923A CA1195923A CA000427031A CA427031A CA1195923A CA 1195923 A CA1195923 A CA 1195923A CA 000427031 A CA000427031 A CA 000427031A CA 427031 A CA427031 A CA 427031A CA 1195923 A CA1195923 A CA 1195923A
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Abstract
COLD STABILIZATION OF AQUEOUS
HERBICIDAL COMPOSITIONS WITH UREA
ABSTRACT OF THE DISCLOSURE
Aqueous herbicidal compositions containing urea and methods of preparations thereof. These composi-tions are characterized by increased resistance to precipitation of the toxicant at temperatures at or below the freezing point of water. When these solutions are returned to room temperature after being partially or completely frozen, stability of components is maintained.
HERBICIDAL COMPOSITIONS WITH UREA
ABSTRACT OF THE DISCLOSURE
Aqueous herbicidal compositions containing urea and methods of preparations thereof. These composi-tions are characterized by increased resistance to precipitation of the toxicant at temperatures at or below the freezing point of water. When these solutions are returned to room temperature after being partially or completely frozen, stability of components is maintained.
Description
28,773 COLD STABILIZATION OF AQUEOUS
HERBICIDAL COMPOSITIONS WITH UREA
The in~ention herein described relates to aqueous herbicid~l compositions containing urea and the active herbicidal ingredient 1,2-dimethyl~3,5-diphenyl-pyrazolium methyl sulfate. At temperatures at or below reezing, the toxicant of these compositions resists pre-cipitation. When solutions of the invention axe partially or completely frozen and then returned to room temperature, stahility of components is maintained.
By way of background, the herbicide 1,2-dimethyl -3,5-diphenylpyrazolium methyl sulfate, known as AVENG
herbicide, is represented by the following structural formula:
fH3 CH3 o CH3504(3 This compound is disclosed in United States Patent No. 3,882,142 ~1975), and has p~oven to be one of the most effective herbicides useful for the selective postemergence control o wild oats (A~ena fatua) in the presence of small grains. The above herbicidal qua~ernary pyrazolium salt is highly coluble in water and allows easy preparation of aqueous concentrates. Such aqueous concent.rates are qulte convenient because of the ease with which they may be diluted prior to application.
~59~3 Although concentrated aqueous solutions of AVENGE herbicide are quite stable at or above room temperatuxe, they rapidly become unstable at temperatures at or below 0C (i.e., in winter storage) and tend to deposit copious amounts of crys-talline 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfa~e. It has been found that once such deposits have formed at cold temperatures in herbicidal concentrAtes, they do not dissolve spontaneous-ly when solutions are allowed to return to room tempera-ture. Consequently, once partially crystallized, such formulations have to be heated and agitated until they enter solution and return to homogeneous form.
A method of preventing this cold-temperature-induced crystallization would make such concentxated herbicidal formulations considerably more desirable by facilitating their use.
In light of the foregoing summary of some demands and lLmitations of conventional herbicidal compositions cont~;~; ng 11 2-dimethyl-3,5-diphenylpyrazolium methyl sul-Eate, improved compositions resistant to cola tempera-ture-induced crystallization of the active toxicant, and methods of preparation thereo, are highly desirable.
Accordingly, an object of this invention is to provide new and usefùl AVENGE herbicide compositions and methods fox their preparation~ This object is manifest in the appended claims~
It has been unexpectedly discovered that incor-poration of ur2a into aqueous herbicidal formulations containing 1,2~dimethyl-3,5~diphenylpyrazolium methyl sul~ate will permit these compositions to be frozen and upon subsequent thawing at room temperature to automatical-ly recon~titute homogeneous solutions. More particularly~
the invention herein described reveals the incorporation of urea in amounts ranging from about 5 to 20% by weight~
and preferably from about 8 to 12% by weight~ into aqueous herbicidal concentrates ContAi ni ng 1,2-dimethyl~3,5-di-phenylpyrazolium methyl sul~ate and a surfactant.
In the preparation of formulaticns of the invention the water component (preferably deionized or distilled and optionally heated to about 40 to 45C) is stirred and about 20% by weight (preferably 12 to 18%) of octylphenoxy polyethoxy ethanol is added. Th~ mixture is stirred until a clear solution results. Then, about 20 to 46% by weight (preferably 2~ to 35%) 1,2-dimethyl 3,5 diphenylpyrazolium methyl sulfa~e and about 5 to 20~ by weight (preerably 8 to 12%) of urea are added and the mixture stirred until a homogeneous solution has formed.
If desired, the resultant solutions may be clarified.
Herbicidal solutions prepared in this manner may be cooled to the point of being partially or completely fro~en, and when subsequently allowed to warm to room temperature form homogeneous solutions without the aid of additional heating and/or stirringO
The liquid non-ionic surfactant referred to above as octylph~noxy polyethoxy ethanol has an average molecular weight of 628 and contains an average of 9 to 10 ethylene oxide units, representing 67% by weight of the surfactant.
The specific gravity of this surfactant is 1.065 at 25C;
the viscosity is 240 cps at 25C (Brookfield; 12 r.p.m.), and the flash point is >148C (TOC~. Alternatively, other similar nonionic surfactants ca~ be substituted for octyl-phenoxy polyet~oxy ethanol. For example, nonylphenoxy polyethoxy ethanol can be used. This compound has an average molecular weight o~ 640 and contains an average of 9 to 10 ethylene oxide unit~. The specific gravity of thls surfactant is 1.056 at 25C, the viscosity is ~40 cps at 25C (Brookfield; 12 r.p.m.) and the flesh point is >148C (TOC~.
Accordingly, a typical formulation may be pre-pared as follows: 1927.7 g water is heated to 40C and 505.5 g octylphen~xy polyethoxy ethanol is added wi~h stirring. Stirring continues until a homogen~ous solution orms. Next, 1348 g of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate (98% pure~ and 32898 g urea ar~ added. The mi~ture is stirred until a clear solution forms. This solution may be chilled below the freezing poin~ of water and then allowed to warm to room temperature to yield a homogeneous solution.
The invention is further illustrated but not limited by the examples set forth below.
General Preparation P~ocedure of aqueous herbicidal solutions for evaluation of storage stability at low temperatures Water ~distilled or deionized) required to make the desired formulation is h ated to about 40 ~o 45C.
The surfactant is added and the mixture is stirred until a homogeneous solution forms. Immediately thereafter 1,2-dimethyl-3,5-diphenylpyrazoli~Ln methyl ;ul~ate and urea are added and the mixture is stirred until a homogeneous solution forms. The solution is cooled to room temperature and stored at -4C (25F) to determine the cold-temperature stability of the solution.
By the above-described procedurP several formula-tions are prepared and evaluat~d. The ccmpo~l~ion o these formulations is given below.
Component* 1 2 3 4 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 99.2~ pure 32O8 32.8 32.8 32.8 Octylphenoxy poly~
ethoxy ethanol 12.3 12,3 1~.3 12.3 Urea 5.0 10.0 - 20.0 Water 49.9 44 9 54 9 34 9 Total 100.0 100.0 100.0 100.0 Units are expressed on a gram weight basis ~9S~3 After storage at -4C (25F) for 5 days, Sample 3 is fully crystallized, Samples 1 and 2 show signs of crystallization and Sample 4 is free of crystals.
Next, the samples are warmed ~o dissolve the crystals, seeded with crystals of 1,2-dimethyl-3,5-diphenylpyrazo-lium methyl sulfate, and again stored at 4C (25F).
After one week's storage, all samples show the presence of significant amounts of crystals. On standing at room temperature, the crystals in Samples 2 and 4 dissolve in about one hours time without agitation or stirring.
Crystals axe present in Samples 1 and 3, even after 24 hours at room temperature.
Preparation aqueous herbicidal solutions for evaluation of storage stahility at low temperatures By t~e procedure of Example 1, four large-scale samples are prepared and evaluated for storage stability at low temperatures. The composition of samples is given below.
~X~MPLE 2 Component Weight % Weight ~ Weight ~ Weight g 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98% pure 1348.0 32.8 1348.0 32.8 1348.0 32.8 1348.0 32.8 ~
Octylphenoxy ~ n polyethoxy I -~
ethanol 505.5 12.3 505.5 12.3 505.5 12.3 505.5 12.3 Urea 2G5.5 5.0 411.0 10.0 822.0 20.0 Water 2256.5 54.9 2051.0 49.9 1845.5 44~9 1434.5 34.9 Total 4110.0 100.0 4110.0 100.0 4110.0 100.04110.0 100.0 -~ 3 C~ ~- ~'r,3 '2 The above samples are stored at -4C (25F).
After two-days storage, the solutions contain no crystalsO
The samples are then seeded with crystals of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate and returned to cold storage. One day after seeding, Samples 1 and 4 are frozen solid, Sample 2 is a mix~ure of ice and herbicide crystals, while Sample 3 is approximately 50~ ice and 50%
solution~ Four days after seeding and storage at -4C
(25F) Samples 1 and 4 are solids contalning some crystals, while Samples 2 and 3 are mixtures of ice and liquid.
Additional storage for a week at the above temperature produces no further visible changes. The samples are then removed from cold storage and allowed to warm slowly~
After two hours, the temperature of the samples rises to ~-2C, Sample 3 is about 75~ solid and Sample 2 is about 25% solid. After about four hours the temperature of the samples rises to 3C. Sample 2 is completely in solution, Sample 3 is about 50% dissolved, and Samples 1 and 4 axe less than 50~ in solution~ One day later all four samples are liquid but Samples 1 and 4-contain crystals of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate.
Preparation of aqueous her~icidal soluti.ons for evaluation of low-temperature storage stab.ility By the procedure of Example 1, three large-scale samples are prepared and eva.luated for storage stability at low temperatures. The CompOSitiGn of the samples i5 given below.
l ~ 3 Weight % Wei~ht ~ Weight ~ i Component (g) (g~ (g~ I
1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 9&% pure 1348~0 32.80 13480~ 32.80 1120.0 2B.oo Octylphenoxy polyethoxy ethanol 505.5 12.30 505.5 12.30 600.0 15.00 Urea 328.8 8.oo 493.2 12.00 320.0 8.00 ~
~later 1927.7 46.go 1763.3 42.90 1960.0 49.00 ~a Total 4110.0 100.00 4110.0 100.004000.p 100.00 All of the above solutions are cold-stored during this experiment at -8C (17.6F). After two days of storage, Samples l and 2 are still mostly liquid and Sample 3 i5 about 2/3 ice + l/3 liquid. After an addi-tional thre~ days o~ storage, Samples 1 and 3 are about
HERBICIDAL COMPOSITIONS WITH UREA
The in~ention herein described relates to aqueous herbicid~l compositions containing urea and the active herbicidal ingredient 1,2-dimethyl~3,5-diphenyl-pyrazolium methyl sulfate. At temperatures at or below reezing, the toxicant of these compositions resists pre-cipitation. When solutions of the invention axe partially or completely frozen and then returned to room temperature, stahility of components is maintained.
By way of background, the herbicide 1,2-dimethyl -3,5-diphenylpyrazolium methyl sulfate, known as AVENG
herbicide, is represented by the following structural formula:
fH3 CH3 o CH3504(3 This compound is disclosed in United States Patent No. 3,882,142 ~1975), and has p~oven to be one of the most effective herbicides useful for the selective postemergence control o wild oats (A~ena fatua) in the presence of small grains. The above herbicidal qua~ernary pyrazolium salt is highly coluble in water and allows easy preparation of aqueous concentrates. Such aqueous concent.rates are qulte convenient because of the ease with which they may be diluted prior to application.
~59~3 Although concentrated aqueous solutions of AVENGE herbicide are quite stable at or above room temperatuxe, they rapidly become unstable at temperatures at or below 0C (i.e., in winter storage) and tend to deposit copious amounts of crys-talline 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfa~e. It has been found that once such deposits have formed at cold temperatures in herbicidal concentrAtes, they do not dissolve spontaneous-ly when solutions are allowed to return to room tempera-ture. Consequently, once partially crystallized, such formulations have to be heated and agitated until they enter solution and return to homogeneous form.
A method of preventing this cold-temperature-induced crystallization would make such concentxated herbicidal formulations considerably more desirable by facilitating their use.
In light of the foregoing summary of some demands and lLmitations of conventional herbicidal compositions cont~;~; ng 11 2-dimethyl-3,5-diphenylpyrazolium methyl sul-Eate, improved compositions resistant to cola tempera-ture-induced crystallization of the active toxicant, and methods of preparation thereo, are highly desirable.
Accordingly, an object of this invention is to provide new and usefùl AVENGE herbicide compositions and methods fox their preparation~ This object is manifest in the appended claims~
It has been unexpectedly discovered that incor-poration of ur2a into aqueous herbicidal formulations containing 1,2~dimethyl-3,5~diphenylpyrazolium methyl sul~ate will permit these compositions to be frozen and upon subsequent thawing at room temperature to automatical-ly recon~titute homogeneous solutions. More particularly~
the invention herein described reveals the incorporation of urea in amounts ranging from about 5 to 20% by weight~
and preferably from about 8 to 12% by weight~ into aqueous herbicidal concentrates ContAi ni ng 1,2-dimethyl~3,5-di-phenylpyrazolium methyl sul~ate and a surfactant.
In the preparation of formulaticns of the invention the water component (preferably deionized or distilled and optionally heated to about 40 to 45C) is stirred and about 20% by weight (preferably 12 to 18%) of octylphenoxy polyethoxy ethanol is added. Th~ mixture is stirred until a clear solution results. Then, about 20 to 46% by weight (preferably 2~ to 35%) 1,2-dimethyl 3,5 diphenylpyrazolium methyl sulfa~e and about 5 to 20~ by weight (preerably 8 to 12%) of urea are added and the mixture stirred until a homogeneous solution has formed.
If desired, the resultant solutions may be clarified.
Herbicidal solutions prepared in this manner may be cooled to the point of being partially or completely fro~en, and when subsequently allowed to warm to room temperature form homogeneous solutions without the aid of additional heating and/or stirringO
The liquid non-ionic surfactant referred to above as octylph~noxy polyethoxy ethanol has an average molecular weight of 628 and contains an average of 9 to 10 ethylene oxide units, representing 67% by weight of the surfactant.
The specific gravity of this surfactant is 1.065 at 25C;
the viscosity is 240 cps at 25C (Brookfield; 12 r.p.m.), and the flash point is >148C (TOC~. Alternatively, other similar nonionic surfactants ca~ be substituted for octyl-phenoxy polyet~oxy ethanol. For example, nonylphenoxy polyethoxy ethanol can be used. This compound has an average molecular weight o~ 640 and contains an average of 9 to 10 ethylene oxide unit~. The specific gravity of thls surfactant is 1.056 at 25C, the viscosity is ~40 cps at 25C (Brookfield; 12 r.p.m.) and the flesh point is >148C (TOC~.
Accordingly, a typical formulation may be pre-pared as follows: 1927.7 g water is heated to 40C and 505.5 g octylphen~xy polyethoxy ethanol is added wi~h stirring. Stirring continues until a homogen~ous solution orms. Next, 1348 g of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate (98% pure~ and 32898 g urea ar~ added. The mi~ture is stirred until a clear solution forms. This solution may be chilled below the freezing poin~ of water and then allowed to warm to room temperature to yield a homogeneous solution.
The invention is further illustrated but not limited by the examples set forth below.
General Preparation P~ocedure of aqueous herbicidal solutions for evaluation of storage stability at low temperatures Water ~distilled or deionized) required to make the desired formulation is h ated to about 40 ~o 45C.
The surfactant is added and the mixture is stirred until a homogeneous solution forms. Immediately thereafter 1,2-dimethyl-3,5-diphenylpyrazoli~Ln methyl ;ul~ate and urea are added and the mixture is stirred until a homogeneous solution forms. The solution is cooled to room temperature and stored at -4C (25F) to determine the cold-temperature stability of the solution.
By the above-described procedurP several formula-tions are prepared and evaluat~d. The ccmpo~l~ion o these formulations is given below.
Component* 1 2 3 4 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 99.2~ pure 32O8 32.8 32.8 32.8 Octylphenoxy poly~
ethoxy ethanol 12.3 12,3 1~.3 12.3 Urea 5.0 10.0 - 20.0 Water 49.9 44 9 54 9 34 9 Total 100.0 100.0 100.0 100.0 Units are expressed on a gram weight basis ~9S~3 After storage at -4C (25F) for 5 days, Sample 3 is fully crystallized, Samples 1 and 2 show signs of crystallization and Sample 4 is free of crystals.
Next, the samples are warmed ~o dissolve the crystals, seeded with crystals of 1,2-dimethyl-3,5-diphenylpyrazo-lium methyl sulfate, and again stored at 4C (25F).
After one week's storage, all samples show the presence of significant amounts of crystals. On standing at room temperature, the crystals in Samples 2 and 4 dissolve in about one hours time without agitation or stirring.
Crystals axe present in Samples 1 and 3, even after 24 hours at room temperature.
Preparation aqueous herbicidal solutions for evaluation of storage stahility at low temperatures By t~e procedure of Example 1, four large-scale samples are prepared and evaluated for storage stability at low temperatures. The composition of samples is given below.
~X~MPLE 2 Component Weight % Weight ~ Weight ~ Weight g 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98% pure 1348.0 32.8 1348.0 32.8 1348.0 32.8 1348.0 32.8 ~
Octylphenoxy ~ n polyethoxy I -~
ethanol 505.5 12.3 505.5 12.3 505.5 12.3 505.5 12.3 Urea 2G5.5 5.0 411.0 10.0 822.0 20.0 Water 2256.5 54.9 2051.0 49.9 1845.5 44~9 1434.5 34.9 Total 4110.0 100.0 4110.0 100.0 4110.0 100.04110.0 100.0 -~ 3 C~ ~- ~'r,3 '2 The above samples are stored at -4C (25F).
After two-days storage, the solutions contain no crystalsO
The samples are then seeded with crystals of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate and returned to cold storage. One day after seeding, Samples 1 and 4 are frozen solid, Sample 2 is a mix~ure of ice and herbicide crystals, while Sample 3 is approximately 50~ ice and 50%
solution~ Four days after seeding and storage at -4C
(25F) Samples 1 and 4 are solids contalning some crystals, while Samples 2 and 3 are mixtures of ice and liquid.
Additional storage for a week at the above temperature produces no further visible changes. The samples are then removed from cold storage and allowed to warm slowly~
After two hours, the temperature of the samples rises to ~-2C, Sample 3 is about 75~ solid and Sample 2 is about 25% solid. After about four hours the temperature of the samples rises to 3C. Sample 2 is completely in solution, Sample 3 is about 50% dissolved, and Samples 1 and 4 axe less than 50~ in solution~ One day later all four samples are liquid but Samples 1 and 4-contain crystals of 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate.
Preparation of aqueous her~icidal soluti.ons for evaluation of low-temperature storage stab.ility By the procedure of Example 1, three large-scale samples are prepared and eva.luated for storage stability at low temperatures. The CompOSitiGn of the samples i5 given below.
l ~ 3 Weight % Wei~ht ~ Weight ~ i Component (g) (g~ (g~ I
1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 9&% pure 1348~0 32.80 13480~ 32.80 1120.0 2B.oo Octylphenoxy polyethoxy ethanol 505.5 12.30 505.5 12.30 600.0 15.00 Urea 328.8 8.oo 493.2 12.00 320.0 8.00 ~
~later 1927.7 46.go 1763.3 42.90 1960.0 49.00 ~a Total 4110.0 100.00 4110.0 100.004000.p 100.00 All of the above solutions are cold-stored during this experiment at -8C (17.6F). After two days of storage, Samples l and 2 are still mostly liquid and Sample 3 i5 about 2/3 ice + l/3 liquid. After an addi-tional thre~ days o~ storage, Samples 1 and 3 are about
2/3 ice + l/3 liquid while Sample 2 is about 1/3 ice +
2/3 liquid. After three more days of storage no further changes are noted in Samples l and 3, but Sample 2 is now about 2y3 ice + 1/3 liquid. When stored at room tempera-ture, all three samples become homogeneous liquids within 24 hours.
Preparation of various formulations of aqueous herbicidal solutions for stability tests at low temperatures By the method of Example l, eight samples are prepared and evaluated for storage stability at low temperatures. The composition of the samples is given below.
1 q 3 4 Weight ~Weight ~ Weight % l~eight Component(~ (g) (g) (~
1~2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98% 164.0 32.8164.0 32.8 164.0 32.8 164.0 32.8 Octylphenoxy po1yethoxy ! ~
ethanol 61.5 12.361.5 12.3 61.5 12.3 61.5 ~ ~n Urea 30.Q 6.o70.0 14.0 80,0 16.0 90.0 18.0 Water 24~.5 48.9204.5 40.9 194.5 38.9 184.5 36.9 Total 500.0 1Q0.0 - 500.0 10Q.0 500.0 100.0500.0 100.0 ;
\
EXAMPLE 4 (Continued3 Weight %Wei~ht %~eight % Weight Component (g~ (q~ ~q) - 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98~ pure 1890.6 46.0140.0 28~0174.2 34~84207.95 41.59 Octylphenoxy polyethoxy ethanol 727.5 17.775.0 15.093.75 1~.75111.90 22.38 Urea 345.3 8.425.6 5.1231. a5 6.37 38.oo 7.60 J
Water 1146.6 27.9259.4 51.88200.2 40.04142.15 28.43 ~a Total 4110.0 tO0.05G0.0 100.0S00.0 100.0 500.0 100.0 ~5~;~3 All samples are stored at -4C (25F) for 24 hours. Examination ShQWS that under these condi~ions, all remained clear liquids and no crys~als formed. The samples are seeded with crystals of 1,2-dimethyl~3,5-diphenylpyrazoli~m methyl sulfate and placed in cold storage at -9C (150F). Four days later, Samples 1, 3, 4, 5, 6, and 8 are completely solidified. Sample 2 r~m~in.~ a liquid and Sample 7 is about 85% liquid and 15 solid. After four hours at room temperature, Samples 1, 6, and 7 are liquids, each containing a small amount (~2~) of crystals; Samples 2 and 3 are clear solutions, while Samples 4, 5, 7 and 8 contain an appreciable amount of crystals. The samples are allowed to warm to 19-~0C
and are then re~m;nedO Sample 1 contains approximately 1% crystalsO Samples 3, 6 and 7 each contain a trace amount of solids whlle Samples 4 and 5 contain abou~ S%
solids. When these samples are shaken, clear so]utions form. Sample 8 contains about 15 to 20% solid~ while Sample 2 is a clear liquid.
EX~MPLE 5 Evaluation of the cold storage stability of herbicidal solutions with and without supplements of urea By the method of Example 1, the following formulations are prepared. Each contains 200 g/liter of 1,2-dimethyl-3,5 diphenylpyrazolium cation. The composi~
tions are given below.
EXAMPI. 5 weigh~ ~eight Component (g3 ~6 1, 2-dimethyl-3, 5-d i pheny l pyrazo l ium .
methyl sulfate 98,~ pure 1 120.0 28.00 1 120 .0 28.00 ()e ty 1 phenoxy polyethoxy etharol 600.0 15.00 600.0 15.00 Urea ~ - 320 . O .8 . 00 w "7 l~ater 2280.0 57.00 1960.0 49.00 Total- 4000 . 0 100 . U 4000 . 0 l O0 . 0 gr-g Samples of both formulation are stored at -20C
and also at -40C for three weeks in 1 gallon translucent plastic jugs~ Samples of Formula 1 are frozen solid at -20C and at -40C. After two days of storage at room temperature (22C), both contain two to three centimeters of a solid white layer below a uniform liquid. Samples of Formula 2 contain frozen crystals throughout the sample volume at -20C. At -40C the top third of the sample contains some ice crystals and about a one-half centimeter layer of large white crystals in the bottom o the container. Both of the above samples form a uniform liquid after two days of storage at room temperature (22C)
2/3 liquid. After three more days of storage no further changes are noted in Samples l and 3, but Sample 2 is now about 2y3 ice + 1/3 liquid. When stored at room tempera-ture, all three samples become homogeneous liquids within 24 hours.
Preparation of various formulations of aqueous herbicidal solutions for stability tests at low temperatures By the method of Example l, eight samples are prepared and evaluated for storage stability at low temperatures. The composition of the samples is given below.
1 q 3 4 Weight ~Weight ~ Weight % l~eight Component(~ (g) (g) (~
1~2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98% 164.0 32.8164.0 32.8 164.0 32.8 164.0 32.8 Octylphenoxy po1yethoxy ! ~
ethanol 61.5 12.361.5 12.3 61.5 12.3 61.5 ~ ~n Urea 30.Q 6.o70.0 14.0 80,0 16.0 90.0 18.0 Water 24~.5 48.9204.5 40.9 194.5 38.9 184.5 36.9 Total 500.0 1Q0.0 - 500.0 10Q.0 500.0 100.0500.0 100.0 ;
\
EXAMPLE 4 (Continued3 Weight %Wei~ht %~eight % Weight Component (g~ (q~ ~q) - 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate 98~ pure 1890.6 46.0140.0 28~0174.2 34~84207.95 41.59 Octylphenoxy polyethoxy ethanol 727.5 17.775.0 15.093.75 1~.75111.90 22.38 Urea 345.3 8.425.6 5.1231. a5 6.37 38.oo 7.60 J
Water 1146.6 27.9259.4 51.88200.2 40.04142.15 28.43 ~a Total 4110.0 tO0.05G0.0 100.0S00.0 100.0 500.0 100.0 ~5~;~3 All samples are stored at -4C (25F) for 24 hours. Examination ShQWS that under these condi~ions, all remained clear liquids and no crys~als formed. The samples are seeded with crystals of 1,2-dimethyl~3,5-diphenylpyrazoli~m methyl sulfate and placed in cold storage at -9C (150F). Four days later, Samples 1, 3, 4, 5, 6, and 8 are completely solidified. Sample 2 r~m~in.~ a liquid and Sample 7 is about 85% liquid and 15 solid. After four hours at room temperature, Samples 1, 6, and 7 are liquids, each containing a small amount (~2~) of crystals; Samples 2 and 3 are clear solutions, while Samples 4, 5, 7 and 8 contain an appreciable amount of crystals. The samples are allowed to warm to 19-~0C
and are then re~m;nedO Sample 1 contains approximately 1% crystalsO Samples 3, 6 and 7 each contain a trace amount of solids whlle Samples 4 and 5 contain abou~ S%
solids. When these samples are shaken, clear so]utions form. Sample 8 contains about 15 to 20% solid~ while Sample 2 is a clear liquid.
EX~MPLE 5 Evaluation of the cold storage stability of herbicidal solutions with and without supplements of urea By the method of Example 1, the following formulations are prepared. Each contains 200 g/liter of 1,2-dimethyl-3,5 diphenylpyrazolium cation. The composi~
tions are given below.
EXAMPI. 5 weigh~ ~eight Component (g3 ~6 1, 2-dimethyl-3, 5-d i pheny l pyrazo l ium .
methyl sulfate 98,~ pure 1 120.0 28.00 1 120 .0 28.00 ()e ty 1 phenoxy polyethoxy etharol 600.0 15.00 600.0 15.00 Urea ~ - 320 . O .8 . 00 w "7 l~ater 2280.0 57.00 1960.0 49.00 Total- 4000 . 0 100 . U 4000 . 0 l O0 . 0 gr-g Samples of both formulation are stored at -20C
and also at -40C for three weeks in 1 gallon translucent plastic jugs~ Samples of Formula 1 are frozen solid at -20C and at -40C. After two days of storage at room temperature (22C), both contain two to three centimeters of a solid white layer below a uniform liquid. Samples of Formula 2 contain frozen crystals throughout the sample volume at -20C. At -40C the top third of the sample contains some ice crystals and about a one-half centimeter layer of large white crystals in the bottom o the container. Both of the above samples form a uniform liquid after two days of storage at room temperature (22C)
Claims (6)
1. A cold-temperature stabilized liquid herbicidal composition comprising on a weight basis about 20 to 46% 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate, 10 to 20% octylphenoxy polyethoxy ethanol, 5 to 20% urea, and water sufficient to total the formula-tion to 100%.
2. A composition according to Claim 1, wherein 32.8% of the formulation is 1,2-dimethyl-3,5-diphenyl-pyrazolium methyl sulfate; 12.3% is octylphenoxy poly-ethoxy ethanol; 8% is urea, and 46.9% is water.
3. A composition according to Claim 1, wherein 28.0% of said formulation is 1,2-dimethyl-3,5-diphenyl-pyrazolium methyl sulfate; 15.0% is octylphenoxy poly-ethoxy ethanol; 8.0% is urea, and 49.0% is water.
4. A composition according to Claim 1, wherein 46.0% is 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate; 17.7% is octylphenoxy polyethoxy ethanol; 8.4 is urea, and 27.9% is water.
5. A composition according to Claim 1, wherein 41.59% is 1,2-dimethyl-3,5-diphenylpyrazolium methyl sulfate; 22.38% is octylphenoxy polyethoxy ethanol; 7.6%
is urea, and 28.43% is water.
is urea, and 28.43% is water.
6. A method for the preparation of a cold-temperature stabilized liquid herbicidal composition, which comprises dissolving on a weight basis about 20 to 46% 1,2-dimethyl-3,5-diphenyl-pyrazolium methyl sulfate, 10 to 20% octylphenoxy polyethoxy ethanol, and 5 to 20%
urea in water sufficient to total the composition to 100%.
urea in water sufficient to total the composition to 100%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US37392782A | 1982-05-03 | 1982-05-03 | |
| US373,927 | 1982-05-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195923A true CA1195923A (en) | 1985-10-29 |
Family
ID=23474477
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000427031A Expired CA1195923A (en) | 1982-05-03 | 1983-04-29 | Cold stabilization of aqueous herbicidal compositions with urea |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1195923A (en) |
-
1983
- 1983-04-29 CA CA000427031A patent/CA1195923A/en not_active Expired
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