CA1207792A - Herbicidal use of trimethylamine and triethylamine salts of 3,5-dibromo-4-hydroxybenzonitrile - Google Patents
Herbicidal use of trimethylamine and triethylamine salts of 3,5-dibromo-4-hydroxybenzonitrileInfo
- Publication number
- CA1207792A CA1207792A CA000438209A CA438209A CA1207792A CA 1207792 A CA1207792 A CA 1207792A CA 000438209 A CA000438209 A CA 000438209A CA 438209 A CA438209 A CA 438209A CA 1207792 A CA1207792 A CA 1207792A
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- Canada
- Prior art keywords
- bromoxynil
- dibromo
- triethylamine
- salt
- hydroxybenzonitrile
- Prior art date
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-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N37/00—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom having three bonds to hetero atoms with at the most two bonds to halogen, e.g. carboxylic acids
- A01N37/36—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom having three bonds to hetero atoms with at the most two bonds to halogen, e.g. carboxylic acids containing at least one carboxylic group or a thio analogue, or a derivative thereof, and a singly bound oxygen or sulfur atom attached to the same carbon skeleton, this oxygen or sulfur atom not being a member of a carboxylic group or of a thio analogue, or of a derivative thereof, e.g. hydroxy-carboxylic acids
- A01N37/38—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom having three bonds to hetero atoms with at the most two bonds to halogen, e.g. carboxylic acids containing at least one carboxylic group or a thio analogue, or a derivative thereof, and a singly bound oxygen or sulfur atom attached to the same carbon skeleton, this oxygen or sulfur atom not being a member of a carboxylic group or of a thio analogue, or of a derivative thereof, e.g. hydroxy-carboxylic acids having at least one oxygen or sulfur atom attached to an aromatic ring system
- A01N37/40—Biocides, pest repellants or attractants, or plant growth regulators containing organic compounds containing a carbon atom having three bonds to hetero atoms with at the most two bonds to halogen, e.g. carboxylic acids containing at least one carboxylic group or a thio analogue, or a derivative thereof, and a singly bound oxygen or sulfur atom attached to the same carbon skeleton, this oxygen or sulfur atom not being a member of a carboxylic group or of a thio analogue, or of a derivative thereof, e.g. hydroxy-carboxylic acids having at least one oxygen or sulfur atom attached to an aromatic ring system having at least one carboxylic group or a thio analogue, or a derivative thereof, and one oxygen or sulfur atom attached to the same aromatic ring system
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- Life Sciences & Earth Sciences (AREA)
- Agronomy & Crop Science (AREA)
- Pest Control & Pesticides (AREA)
- Plant Pathology (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Dentistry (AREA)
- General Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Agricultural Chemicals And Associated Chemicals (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT
'THE HERBICIDAL USE OF TRIMETHYLAMINE
AND TRIETHYLAMINE SALTS OF 3,5-DIBROMO-4-HYDROXYBENZONITRILE"
The use of the trimethylamine and triethylamine salts of 3,5-dibromo-4-hydroxy-benzonitrile to control selectively the growth of broad-leafed weeds by post-emergence application in maize and sorghum crops, herbicidal compositions containing these salts and, optionally, other herbicides and a process for the preparation of these salts are described. The triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile is a new compound.
'THE HERBICIDAL USE OF TRIMETHYLAMINE
AND TRIETHYLAMINE SALTS OF 3,5-DIBROMO-4-HYDROXYBENZONITRILE"
The use of the trimethylamine and triethylamine salts of 3,5-dibromo-4-hydroxy-benzonitrile to control selectively the growth of broad-leafed weeds by post-emergence application in maize and sorghum crops, herbicidal compositions containing these salts and, optionally, other herbicides and a process for the preparation of these salts are described. The triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile is a new compound.
Description
DESCRIPTION
"NEW HE~BICIDAL METHOD'~
This inven~ion relates to a new me~hod for the . control of weeds in crops of maize and sorghum~
5It is known, for example from British Paten~ No 1,030,249 and British Patent No 1,067,032, that 3,5-dibromo-4-hydroxybenzonitrile (hereinafter re~erred to as Ibromoxynil') and its esters and alkali metal, alkaline earth metal9 ammonium and amine salts~
possess valuable herbicidal properties, more e~pecially for the selecti~e control of broad-leafed weeds in cereal crops by post-emergence application.
(By the term 'post-emergence application', as used in ~he presen~ ~pecifica~ion, îs meant application to the `aerial or exposed portions o broad-leafed ~eeds ~fter emergence above the surface of the soil~.
Bromoxynil has been used extensively as a berbicide for many years, the vast preponderance o this usage being in the form of the octanoate ester or an alkali metal salt 9 especially the potassium salt, of brom~xynil, for the selective control of broad-lea~ed weeds in cereal crops by post-emergence application.
`'~
1, .
, 7~
. - 2 -Bromoxynil esters, particularly the octanoate ester,ha~e been used extensively for post-emergence broad~lea~ed weed contlol in small grain cereals, especially wheat, harley and oats, giving good control of the weeds without causing significant damage to the small grain cereal crop. However, the use of bromoxynil octanoate for post-emergence broad-leafed weed control in the wider-leafed cereals maize ~Zea ~ ) and sorghum (Sor~hum bicolor) has been restricted owing to transient phytotoxicîty, which occurs in the form of necrosis of the sprayed leaves, caused ~o the crop plan~. The margin of safety . between the rate of application of bromoxynil octanoate required fo~.effective control of broad~leafed weeds and the rate of application of bromoxynil octanoate which causes damage to crops o maize and sorghum is narrow~ Bromoxynil octanoate has, therefore J a narr~w margin of selectivity or a - low selectivity index (the ratio between the rate o~
application of a herbicide tolerated by the crop and the rate of application of the herbicide required for satisfactory weed control) when used to control the growth of broad-leafed weeds in maize and sorghum : crops by post-emergence application. In marked ~ 25 contrast, bromoxynil octanoate has a high selectivity ~07792 ` 3 --index in controlling thP growth of broad-leaed weeds by post-emergence application in small ~rain crops, such as wheat, where it has been used successfully for many years.
Alkali metal sal~s of bromoxynil, particularly the potassium salt, are tolerated by small grain cereals and maize and sorghum at much hi~her rates of application than i~ the case with bromoxynil octanoate, but the control of the growth of I0 broad-lea~ed weeds which is obtained is considerably poorer and less reliable ~han that produced by bromoxynil octanoateO For this reason, there has been r.o extensive use of bromoxynil potassium salt alone for weed conSrol in cereals, although lt has often been used admixed with other her~icides in herbicidal formulations used for the control of broa~-leafed weeds in small grain cerea~ crops.
Accordingly, neither of the two bromoxynil : derivatives which have bitherto been widely used for controlling the growth of broad-leafed weeds in small grain cereal crops, namely bromoxynil octanoate and bromoxynil potassium salt, are extensively used to control the growth of weeds in maize or sorghum crops.
' . ' .
, . .
~2l~ 9z Numerous amine salts of bromoxynil have been described as herbicides but none have hitherto been used e:.tensively in agriculture.
~ s a result of research and experimen~ation, it has now been unexpec~edly found that the trime~hylamine and, more especially, the triethylamirle salts of bromoxynil ~hereinafter re~erred ~o collectively as the 'bromoxynil trimPthyl- a~d triethyl-amine salts') are very much more active in the control of broad-leafed weeds than bromoxynil potassium salt while being substantially less damaging to maize (Zea mays) and sorghum (Sorghum bicolor) than bromoxynil octanoa~e. Accordingly 9 the bromoxynil trimethyl~ and triethyl-amine salts as hereinbe~ore deined have a much greater margin of selectivity or selectivity index than bromoxynil octanoate on the control of the growth of broad-leafed weeds by post-em~rgence application in maize and sorghum crops and are substantially more active, with a greater margin of ~electivity, in controlling the growth o~ broad-leafed weeds by post emergence applica.ion in maize and sorghum crops than bromoxynil potassium salt, thereby representing a major advance in the control of broad-leafed weeds in crops of maize and sorghum. Bromoxynil trimethylamine and : triethylamine salts are also more active, wit~ a much 75~
greater margin of selectivity, in controlling the grow~h of broad-leafed weeds by post-emergence application iD maize and sorghum crops than other amine salts of bromoxynil which have been tested~ i.e.
bromoxynil trie~hanolamine, tri-n-propylamine, tri-n-butylamine, methyl-di-n-octylamine and ammonium salts. The bromoxynil trimethyl- and triethyl-amine salts, and more ~specially bromoxynil triethylamine salt, are satisfactorily tolerated by maize or corn (Zea mays) and sorghum (Sor~hum bicolor) at rates of application, in particular of from 100 to lOOOg p.e./hectare, and more especially of from 150 to 600g p.e./hectare, whlch provide satisfactory control of - i - the growth of broad~Ieafed weeds by post-emergence applicaticn. (By the term 'p.e. 7 as used in tbe pres~nt speciication is meant ' phenol equivalent' or the bromoxynil content of the trimethylamine or triethylamIne salt of bromoxynil or other bromoxynil deriva~ive applied).
Accordingly9 the present invention provides a method for the selective control of broad-leafed weeds in an emerged crop of maize ( 2ea mays) or sorghum (Sorqhum bicolor)w~ich comprises the post-emergence application to the broad-leafed weeds in a crop of maize or sorghum of a herbicidally-effective amount which does not cause substantial permanent damage to the crop of the trime~hylamine salt of bromoxynil or, preferably, the triethylamine salt of bromoxynil, particularly at a rate of applicatlon of from 100 to lOOOg p.e./hectare and more especially at a ra~e of application of ~rom 150 to 600g p.e./hectare.
Bromoxynil trimethyl- and triethyl-amine salts may, in particular, be used, according to th~ present invention, to control the growth of the broad-leafed w~ed species Abutilon theophrasti, ~maranthus ~
e.g. Amaranthus retroflexus, Ambrosia artemisiifolia, ~ _ _ _ _ Amsinkia intermedia, Anchusa arvensis, Anthemis cotula, Ascelepias ~pp., Aethusa cynap;um, Atriplex patula, Brassica kaber, Brassica nigra, Capsella .
b~. _a La~r~ri~, Centaurea cyanus, Chen~podium album, Chorispora tenella, Datura s~ramonium, Descurainea _ sophia, FaRopyrum tartaricum, Galinsoga parviflora3-Helianthus annuus, Ipomea spp., e.g. Ipomea purpurea ___ and Ipomea hederifQlia, Kochia scoparia, Lapsana con~un;s Lithospermum arvense, ~latricaria recutita~
Matrica~ia inodora, Myosotis arvensis, ~ r _ as, Planta~ media, Poly~on~lm spp., e.~. Polygonum aviculare3 Poly~onum convolvulus, Polygonum athifolium, Poly~onum persicaria, Poly~onum pt-:nsylvanicum and Poly~onum scabrum, Portulaca oleracea, Raphanus raphanistrum, Senecio vulgaris, Sida spinosa, Silene alba, Sinapis arvPnsis, Solanum ni~rum, Solanum elaea~nifolium, Sonchus ~
Sonchus oleracea, Thlaspi arvense, Veronica persica and ... ~ . . .. .
` ~077~Z
Xanthium spp., e.g. Xanthium strumarium, Xanthium .
pensylvanicum and Xanthium canadensis, in maize and sorghum crops by post~emergence application, and more especially to control the grow~h of Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, ~E~ purpurea, Polygonum lapathifolium, Solanum and Xanthium strumarium? which present particularly difficult problems of weed control in maize and sorghum crops.
It is to be understood that in carrying out the - method of controlling the growth of broad-leafed weeds - according to the present invention, mixtures of the ; . t~ime~hylamine salt of bromoxynil and the triethylamine salt of bromoxynil in any proportions may, if desired, be used.
- Bromoxynil trimethyl- and triethyl-amine salts may be used alone to control the growth of - broad-leafed weeds in maize or sorghum crops by : . pa2t-emergence application or may be applied to control.the growth o~ broad-leafed weed~ in maize or sorghum crops by post-emergence application in eonjunction with other herbicides which eontrol ~he growth o monocotyledonous, e.g. grass 7 weeds and/or which are herbicidally active by residual or 25 pre-emergence application and/or which possess persistent hcrbicidal activity and which aro well :-tolerated by maize and sorghum. (By the terms'residual application' and 'pre-emergence application is meant application to ~he soil in which the weed seeds or seedlings are presen~ before emergence oE the weeds above the surface of the soil). Suitable herbicides include atrazine (2-chloro-4~ethylamino-6-isopropylamino-1,3,5-triazine) 9 simazine ~2-chloro-4,6-bis(ethylamino)-1,3,5-triazine], cyanazine [2-(4-chloro-6-ethylamino-1,3>5-tria~in-2-ylamino)-~-methyl propionitrile], propazine ~2-chlorv-4,6-bis-~isopropylamino~-1,3,5-triazine], terbuthylazine (2-tert-butylamino-4-chloro-6-ethylamino-1,3,5-triazine), linuron l3-(3,4-dichlorophenyl)-1-methoxy-l-methylurea], isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea~, dinoseb acetate (2-sec-butyl-4,6-dinitrophenyl acetate), dinoseb amine (alkanolamine salts of 2-sec-butyl-4,6-dlnitrophenol)j dinoterb (2-tert-butyl-4,6-dinitrophenol~, dicamba (3,6-dichloro-
"NEW HE~BICIDAL METHOD'~
This inven~ion relates to a new me~hod for the . control of weeds in crops of maize and sorghum~
5It is known, for example from British Paten~ No 1,030,249 and British Patent No 1,067,032, that 3,5-dibromo-4-hydroxybenzonitrile (hereinafter re~erred to as Ibromoxynil') and its esters and alkali metal, alkaline earth metal9 ammonium and amine salts~
possess valuable herbicidal properties, more e~pecially for the selecti~e control of broad-leafed weeds in cereal crops by post-emergence application.
(By the term 'post-emergence application', as used in ~he presen~ ~pecifica~ion, îs meant application to the `aerial or exposed portions o broad-leafed ~eeds ~fter emergence above the surface of the soil~.
Bromoxynil has been used extensively as a berbicide for many years, the vast preponderance o this usage being in the form of the octanoate ester or an alkali metal salt 9 especially the potassium salt, of brom~xynil, for the selective control of broad-lea~ed weeds in cereal crops by post-emergence application.
`'~
1, .
, 7~
. - 2 -Bromoxynil esters, particularly the octanoate ester,ha~e been used extensively for post-emergence broad~lea~ed weed contlol in small grain cereals, especially wheat, harley and oats, giving good control of the weeds without causing significant damage to the small grain cereal crop. However, the use of bromoxynil octanoate for post-emergence broad-leafed weed control in the wider-leafed cereals maize ~Zea ~ ) and sorghum (Sor~hum bicolor) has been restricted owing to transient phytotoxicîty, which occurs in the form of necrosis of the sprayed leaves, caused ~o the crop plan~. The margin of safety . between the rate of application of bromoxynil octanoate required fo~.effective control of broad~leafed weeds and the rate of application of bromoxynil octanoate which causes damage to crops o maize and sorghum is narrow~ Bromoxynil octanoate has, therefore J a narr~w margin of selectivity or a - low selectivity index (the ratio between the rate o~
application of a herbicide tolerated by the crop and the rate of application of the herbicide required for satisfactory weed control) when used to control the growth of broad-leafed weeds in maize and sorghum : crops by post-emergence application. In marked ~ 25 contrast, bromoxynil octanoate has a high selectivity ~07792 ` 3 --index in controlling thP growth of broad-leaed weeds by post-emergence application in small ~rain crops, such as wheat, where it has been used successfully for many years.
Alkali metal sal~s of bromoxynil, particularly the potassium salt, are tolerated by small grain cereals and maize and sorghum at much hi~her rates of application than i~ the case with bromoxynil octanoate, but the control of the growth of I0 broad-lea~ed weeds which is obtained is considerably poorer and less reliable ~han that produced by bromoxynil octanoateO For this reason, there has been r.o extensive use of bromoxynil potassium salt alone for weed conSrol in cereals, although lt has often been used admixed with other her~icides in herbicidal formulations used for the control of broa~-leafed weeds in small grain cerea~ crops.
Accordingly, neither of the two bromoxynil : derivatives which have bitherto been widely used for controlling the growth of broad-leafed weeds in small grain cereal crops, namely bromoxynil octanoate and bromoxynil potassium salt, are extensively used to control the growth of weeds in maize or sorghum crops.
' . ' .
, . .
~2l~ 9z Numerous amine salts of bromoxynil have been described as herbicides but none have hitherto been used e:.tensively in agriculture.
~ s a result of research and experimen~ation, it has now been unexpec~edly found that the trime~hylamine and, more especially, the triethylamirle salts of bromoxynil ~hereinafter re~erred ~o collectively as the 'bromoxynil trimPthyl- a~d triethyl-amine salts') are very much more active in the control of broad-leafed weeds than bromoxynil potassium salt while being substantially less damaging to maize (Zea mays) and sorghum (Sorghum bicolor) than bromoxynil octanoa~e. Accordingly 9 the bromoxynil trimethyl~ and triethyl-amine salts as hereinbe~ore deined have a much greater margin of selectivity or selectivity index than bromoxynil octanoate on the control of the growth of broad-leafed weeds by post-em~rgence application in maize and sorghum crops and are substantially more active, with a greater margin of ~electivity, in controlling the growth o~ broad-leafed weeds by post emergence applica.ion in maize and sorghum crops than bromoxynil potassium salt, thereby representing a major advance in the control of broad-leafed weeds in crops of maize and sorghum. Bromoxynil trimethylamine and : triethylamine salts are also more active, wit~ a much 75~
greater margin of selectivity, in controlling the grow~h of broad-leafed weeds by post-emergence application iD maize and sorghum crops than other amine salts of bromoxynil which have been tested~ i.e.
bromoxynil trie~hanolamine, tri-n-propylamine, tri-n-butylamine, methyl-di-n-octylamine and ammonium salts. The bromoxynil trimethyl- and triethyl-amine salts, and more ~specially bromoxynil triethylamine salt, are satisfactorily tolerated by maize or corn (Zea mays) and sorghum (Sor~hum bicolor) at rates of application, in particular of from 100 to lOOOg p.e./hectare, and more especially of from 150 to 600g p.e./hectare, whlch provide satisfactory control of - i - the growth of broad~Ieafed weeds by post-emergence applicaticn. (By the term 'p.e. 7 as used in tbe pres~nt speciication is meant ' phenol equivalent' or the bromoxynil content of the trimethylamine or triethylamIne salt of bromoxynil or other bromoxynil deriva~ive applied).
Accordingly9 the present invention provides a method for the selective control of broad-leafed weeds in an emerged crop of maize ( 2ea mays) or sorghum (Sorqhum bicolor)w~ich comprises the post-emergence application to the broad-leafed weeds in a crop of maize or sorghum of a herbicidally-effective amount which does not cause substantial permanent damage to the crop of the trime~hylamine salt of bromoxynil or, preferably, the triethylamine salt of bromoxynil, particularly at a rate of applicatlon of from 100 to lOOOg p.e./hectare and more especially at a ra~e of application of ~rom 150 to 600g p.e./hectare.
Bromoxynil trimethyl- and triethyl-amine salts may, in particular, be used, according to th~ present invention, to control the growth of the broad-leafed w~ed species Abutilon theophrasti, ~maranthus ~
e.g. Amaranthus retroflexus, Ambrosia artemisiifolia, ~ _ _ _ _ Amsinkia intermedia, Anchusa arvensis, Anthemis cotula, Ascelepias ~pp., Aethusa cynap;um, Atriplex patula, Brassica kaber, Brassica nigra, Capsella .
b~. _a La~r~ri~, Centaurea cyanus, Chen~podium album, Chorispora tenella, Datura s~ramonium, Descurainea _ sophia, FaRopyrum tartaricum, Galinsoga parviflora3-Helianthus annuus, Ipomea spp., e.g. Ipomea purpurea ___ and Ipomea hederifQlia, Kochia scoparia, Lapsana con~un;s Lithospermum arvense, ~latricaria recutita~
Matrica~ia inodora, Myosotis arvensis, ~ r _ as, Planta~ media, Poly~on~lm spp., e.~. Polygonum aviculare3 Poly~onum convolvulus, Polygonum athifolium, Poly~onum persicaria, Poly~onum pt-:nsylvanicum and Poly~onum scabrum, Portulaca oleracea, Raphanus raphanistrum, Senecio vulgaris, Sida spinosa, Silene alba, Sinapis arvPnsis, Solanum ni~rum, Solanum elaea~nifolium, Sonchus ~
Sonchus oleracea, Thlaspi arvense, Veronica persica and ... ~ . . .. .
` ~077~Z
Xanthium spp., e.g. Xanthium strumarium, Xanthium .
pensylvanicum and Xanthium canadensis, in maize and sorghum crops by post~emergence application, and more especially to control the grow~h of Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, ~E~ purpurea, Polygonum lapathifolium, Solanum and Xanthium strumarium? which present particularly difficult problems of weed control in maize and sorghum crops.
It is to be understood that in carrying out the - method of controlling the growth of broad-leafed weeds - according to the present invention, mixtures of the ; . t~ime~hylamine salt of bromoxynil and the triethylamine salt of bromoxynil in any proportions may, if desired, be used.
- Bromoxynil trimethyl- and triethyl-amine salts may be used alone to control the growth of - broad-leafed weeds in maize or sorghum crops by : . pa2t-emergence application or may be applied to control.the growth o~ broad-leafed weed~ in maize or sorghum crops by post-emergence application in eonjunction with other herbicides which eontrol ~he growth o monocotyledonous, e.g. grass 7 weeds and/or which are herbicidally active by residual or 25 pre-emergence application and/or which possess persistent hcrbicidal activity and which aro well :-tolerated by maize and sorghum. (By the terms'residual application' and 'pre-emergence application is meant application to ~he soil in which the weed seeds or seedlings are presen~ before emergence oE the weeds above the surface of the soil). Suitable herbicides include atrazine (2-chloro-4~ethylamino-6-isopropylamino-1,3,5-triazine) 9 simazine ~2-chloro-4,6-bis(ethylamino)-1,3,5-triazine], cyanazine [2-(4-chloro-6-ethylamino-1,3>5-tria~in-2-ylamino)-~-methyl propionitrile], propazine ~2-chlorv-4,6-bis-~isopropylamino~-1,3,5-triazine], terbuthylazine (2-tert-butylamino-4-chloro-6-ethylamino-1,3,5-triazine), linuron l3-(3,4-dichlorophenyl)-1-methoxy-l-methylurea], isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea~, dinoseb acetate (2-sec-butyl-4,6-dinitrophenyl acetate), dinoseb amine (alkanolamine salts of 2-sec-butyl-4,6-dlnitrophenol)j dinoterb (2-tert-butyl-4,6-dinitrophenol~, dicamba (3,6-dichloro-
2-methoxybenzoic acid) and salts thereof with metals, e.g. sodium or potassium, or amines, e.g~
dimethylamine, and the phenoxyacetic acid herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and MCPA
(2-methyl-4-chlorophenoxyacetic acid) and their salts with metals, e.g. sodium or potassium, or amines, ~or example alkylamines, e.g. monomethylamine, dimethylamine, isopropylamine or triethylamine, or ~77~;2 g ~lkanolamines, e.g. diethanolamine, triethanolamine or mixed isopropanolamines, or their esters having low volatility7 for example their esters with butoxyethanol, propylene glycol, tetrahydrofurfuryl alcohol, butoxypropanolj ethylhexanol or iso-octanol.
Bromoxynil t~imethyl- and triethyl-amine salts may be applied alone or -in combination with the other herbicides indicated above to control the growth of broad-leafed weeds in maize and sorghum crops by post-emergence application after ~he emergence of both the broad-leafed weeds and the crop. If desired, tbis post-emergence application of bromoxynil trimethyl-and triethyl-amine salts may follow the pre-emergence or pre-planting application to a locus which is an srea planted with or to be planted with a maize or sorghum crop, if desired with incorporation into the soil, o~ one or more of the following herbicides:-alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)-acetanilide~, metolachlor ~2-chloro-6'-ethyl-N-(2~methoxy-1-methylethyl)acet-o-toluidide], pendimethalin ~N-(l-ethylpropyl)-~,6-dinitro-
dimethylamine, and the phenoxyacetic acid herbicides 2,4-D (2,4-dichlorophenoxyacetic acid) and MCPA
(2-methyl-4-chlorophenoxyacetic acid) and their salts with metals, e.g. sodium or potassium, or amines, ~or example alkylamines, e.g. monomethylamine, dimethylamine, isopropylamine or triethylamine, or ~77~;2 g ~lkanolamines, e.g. diethanolamine, triethanolamine or mixed isopropanolamines, or their esters having low volatility7 for example their esters with butoxyethanol, propylene glycol, tetrahydrofurfuryl alcohol, butoxypropanolj ethylhexanol or iso-octanol.
Bromoxynil t~imethyl- and triethyl-amine salts may be applied alone or -in combination with the other herbicides indicated above to control the growth of broad-leafed weeds in maize and sorghum crops by post-emergence application after ~he emergence of both the broad-leafed weeds and the crop. If desired, tbis post-emergence application of bromoxynil trimethyl-and triethyl-amine salts may follow the pre-emergence or pre-planting application to a locus which is an srea planted with or to be planted with a maize or sorghum crop, if desired with incorporation into the soil, o~ one or more of the following herbicides:-alachlor [2-chloro-2',6'-diethyl-N-(methoxymethyl)-acetanilide~, metolachlor ~2-chloro-6'-ethyl-N-(2~methoxy-1-methylethyl)acet-o-toluidide], pendimethalin ~N-(l-ethylpropyl)-~,6-dinitro-
3,4-xylidine~, butylate (S-ethyl di-isobutyl-thiocarbamate~, vernolate (S-propyl dipropylthio-carbamate), EPTC (S-ethyl dipropylthiocarbamate~ or a mixture (1~:1) of EPTC and ~,N-diallyl-2,2 dichloroacetamide.
7~2 For use i~ the method of con~rolling the growth of broad-leafed weeds according to the present invention, the trimethylamine and ~riethylamine salts of bromoxynil may be applied in herbicidal compositions comprising at.least one of the trimethyl-amine and triethylamine salts of bromoxynil in association with, and preferably homogeneously dispersed in, one or more compatible herbicidally-acceptable diluents or carriers or surface-ac~ive agen,s (i.e. diluents or carriers or surface-active agents of the ~ype generally accep~ed in the art as being sui~able for use in herbicîdal compositions and which are compatible with the bromoxynil trimethyl-. and triethyl-amine salts). The term "homogeneously......... .. .
dispersed" is used to include compositions in which the bromoxynil trimethyl- and triethyl-amine salts are dissolved in the other components. The term "herbicidal compositions" is used in a broad sense to include not only compositions which are ready for use 2D as herbicides but also concentrates which must be diluted before ~se. Preferably, the compositions contain from 0.05 to 90~ by weight of at least one of the trim~hylamine and triethylamine salts of bromoxynil.
The herbicidal compositions may contain both a diluent or carrier and a surface-active (e.g. wetting, dispersingJ or emulsiying) agent. Surface-active agents which may be present in herbicidal compositions used in the present invencion may be of the ionic or non-ionic types, for example sulphoricinoleates, quaternary ammonium derivatives, products based on condensates of ethylene oxide ~ith alkyl, e.g. nonyl or octyl, vr polyaryl phenols, or carboxylic acid 1~ es~ers of anhydrosorbitols which have been rendered soluble by etheri~ication of the free hydroxy groups by condensation with ethylene oxide, alkali and alkaline earth salts o~` sulphuric acid esters and sulphonic acids such as dinonyl- and dioctyl-sodium sulphono-succinates, alkali and alkaline earth metal salts of high molecular weight sulphonic acid derivatives such as sodium and calcium lignosulphonates and sodium and calcium alkyl benzen~
sulphonates.
Suitably, her~icidal compositions may comprise from 0.01 to 10~/~ by weight of surface-~tive agent but, if desired, herbicidal compositions used in the present invention may comprise higher proportions of surface-active agent, or example up ~o 15% in liquid emulsifiable suspension concentrates and up to 25% in liquid water soluble concentrates.
%
Examples of suitable solid diluents or carriers are aluminium silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, adsorbent carbon black and elays such as kaolin and ben~onite. Th~ solid compositions (which may ~ake tbe form of dusts, granules or wettable powders~ are preferably prepared by grinding the brom~xynil trimethyl- and triethyl-amine salts with solid diluents or by impregnating the solid diluents or carriers with solutions of the bromoxynil trimethyl-and triethyl-amine salts in vola~ile solvents, evaporating thP solvents and, i~ necessary, grinding the products so as to obtain powdersO Granular formulations may be p~epared by absorbing the bromoxynil trimethyl- and triethyl-amine salts (dissolved in suitable solvents) onto ~he solid diluents or carriers in granular form and, i necessary, re~oving excess solvent, e~g. by evaporation, or by granulating compositions in powder 2~ form obtained as described above Solid herbicidal compositions, particularly wettable powders and granules, may contain wetting or dispersing agent (for example of the types described above), which may also, when solid, serve as diluents or carriersO
~77~2 Liquid compositions may take the form of aqueous, organic or aqueous-organic solutions, suspensions and emulsions which may incorporate a surace-actiYe agent. Suita~le liquid diluents for incorporation in the liquid compositions include water, glycols, tetrahydrofurfuryl alcohol, acetophenone, cyclohexanone, isophorone, tolueDe, xylene and mineral, animal and vegetable oils, e.g.
light aromatic and naphthenic pe~roleum fractions (and mixtures of these diluents). Surface-active agents, which may be present in the liquid compositions, may be icnic or non-ionic (for example of the types described above) and may, when liquid, also serve as diluents or carriersO -Wettable powders, dispersible granules and liq~id compositions in the form of concentratés may be diluted ~ith water or other suitable diluents, fo.
example mineral or vegetable oils 9 particularly in the case of liquid concentrates in which the diluent or carrier is an oil, to give compositions ready foruse. When desired, liquid compositions of the bromoxynil trimethyl- and triethyl-amine salts may be used in the form of self-emulsifying concentrates compris.ing the active s~bstances dissolved in the emulsifying agents or in solvents containing emulsifying agents compatible wi~h the active substances, the si~ple ~ 7~ ~ .
addition of such concentrates to water producing compositions ready for useO
Liquid concentrates in which the diluent or carrier is an oil may b used without fur~her dilu~ion using the electrostatio spray technique.
Herbicidal compositions may also contaiD~ if desired, conventional adjuvants such as adhesives~
protective colloids~ thickeners, penetrating agen~s, st~bilisers, sequesterin~ agen~s, anti-caking agen~s~
colouring agents and corrosion inhibitors. These adjuvants may also serve as carriers or diluents.
Preferred herbieidal compositions are wettablc powders which comprise from 10 to 90~/O w~w of at least one of the trimethylamîne and triethylamine salts of bromoxynil, from 2 to 10% w/w of surface-active agent and rom 10 to 88% w/w of solid diluent or carrier;
liquid water-miscible concentrates which comprise from 5 to 50% w/v o~ at least one o the trimethylamine and triethylamine salts of bromoxynil9 from 5 to 25UZ wlv o~ surface-active agent and from 25 to 90~/O by volume of water-miscible solvent~ e.g. dimethylformamide, or a mixt~lre of water-miscible solvent and wa~er;
granules which comprise from 1 to 90% wlw of at least one of the trimethyla~ine and triethylamine salts of bromoxynil, from 0.5 to 2.5% w/w of surface-active agent and from 7.5 to g8~5~/o w/w of granular c~rrier, 7~2 and emulsifiable concen~rates which comprise from 0.05 to ~OV/o wJv, and preferably from 1 to 60~/~ w/v, of at least one ~f the trimethylamine and triethylamine salts of bromoxynil, ~rom 0.01 to 10~/~ w/v, and preferably ~rom 1 to 10% wlv, of surface-active agent and from 9.99 to 99.~4%, and preferably from 39 to 58.99~/~, by volume of organic solvent.
Herbicidal compositions may also comprise the bromoxynil trimethyl- and triethyl-amine sal~s in association with, and preferably homogeneously dispersed in, one or more other herbicides as hereînbefore described which may be used in conjunction with the trimethylamine and triethylamine salts o~ bromoxynil and, if desired one or more compatible pesticidally accep~able diluents or carriers, surface-active agents and conventional adjuvants as hereinbefore described.
The bromoxynil trimethyl- and ~riethyl-amine salts may be prepared by reacting stoichiometric amounts of bromoxynil and trimethylamine or triethylamine in a suitable inert solvent, for example a liquid diluent suitable for incorporation in liquid herbicidal compositions used in the present invention as hereinbefore described, or mixtures thereof, or a lower aliphatic alcohol, e.g. methanol . ^ ` ,, , ~ .
or ethanol, or acetone, if necessary with heating. If desiredl a stoichiometric amount of a mixture of trimethylamine and triethylamine may be used~ The bromoxynil trimethyl- and triethyl-amine salts or mixtures thereof may, 5 if desired, be iso~ated from the reaction mixture by conventional methods, for example by filtration, if necessary after the partial or complete removal of the solvent, e.g. by evaporation. However, it i5 frequently more convenient to use the solution of the trimethylamine or triethylamine salts 10 or ~romoxynil or mixtures thereof in a solvent which is obtained directly in the preparation of herbicidal compositions used in the present invention, particularly liquid herbicidal compositions, withou~ isolating the bromoxynil trimethyl- and triethylamine salts. When reacting 15 bromoxynil with trimethylamine or triethylamine or mixtures thereof in a solvent to give a solution of the trimethylamine or triethylamine salt of bromoxynil or mixtures thereof suitable for use directly in the preparation of herbicidal compositions, more especially liquid water-miscible 20 concentrates and wettable powders, according to the present invention, without isolation of the bromoxynil trimethyl- and triethyl-amine salts or mixtures thereof, it is preferred to use a slight excess of trimethylamine or triethylamine or mixture thereof over the stoichiometric amount in order to 25 give a solution o pH8.5 to pH9.5. If desired other components of herbicidal compositions, for example surface j~,^` ', ~2077g?
active agents, may be included in the solvent in which the trimethylamine or triethylamine salt of bromoxynil or mixtures thereof is prepared.
Bromoxynil triethylamine salt is a new compound 5 which, together with its process of preparation form further features of the present invention. When a herbicidal composition comprises bromoxynil triethylamine salt and water or a common organic solvent a surface active agent is preferably present.
7~2 _ ~8 -The Eollowing Examples illustrate herbicidal compositions used in the present invention.
A water-miscible composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ..................... 34% w/v (weight/volume) triethylamine .................. 15% w/v Soprophor* BSU (tristyrylphenol/ethylene oxide condensate containing 18 moles of e~hylene oxide ......... 1.5% w1v diethylene glycol ............ ,. 25% wfv water .................... to 100% by volume, by mixing together a portion of the water, the diethylene glycol, the bromoxynil and the triethylamine (15~/~ w/v of triethylamine represents a ~.6V/o by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine sal~) with heating and stirring. The Soprophor* BSU was then added and the volume was made up to 100% by the addition of water. The resulting clear brown liquid of pH9 was completely miscible with water and may be diluted with water and applied at a rate of 0.5 litres of water miscible composition in 100 to 300 li~res of spray fluid per * trade mark ~ ` J
7~
~ 9 hectare ~an application rate of 170g of bromoxynil p.e.
per hectare) ~o control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Cheno~od_um album, Ipomea ~purea, Polygonum lapathifolium, Solanum ni~rum and Xan~hium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
A similar water-miscible composi~ion containing bromoxynil trimethylamine salt may be prepared as described above by replacing the tr;ethylamine by the appropria~e amount of trimethylamine and used in a similar manner.
An emulsifi~ble composi~ion containing bromoxynil triethylamine salt was prepared from:
bromoxynil ~ 34% w/v triethylamine .................... 12.4% w/v Soprophor* BSU .........~........ ~.5.25% w/v Arylan* CA (70~/O solution of calcium dodecyl benzene sulphonate).. 2.25% w/v cyclohexanone ................ ... 7.5~lO ~/v (volume/volume) Solvesso* 150 (aromatic C10 fraction of petroleum) to 100% by volume, trade marks ~7~7~
, ., ~ 2~
by mixing together the cyclohexanone, the bromoxynil and ~he triethylamine and a portion of the Solvesso* 150 with heating and stirring. The Soprophor* BSU and the Arylan*
CA were then added and the volume was made up to 100% by the addition of Solvesso* 150. The resulting clear brown liquid was self-emulsifiable in water and may be diluted with water and applied at a rate of 1.5 litres of emulsifiable composition in 100 to 300 litres of spray ~luid per hectare (an application rate of 510g of bromoxynil p.e. per hectare) to control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retrof _ us, Chenopodium album, I~omea purpurea, Poly~onum lapathifolium, Solanum nigrum and Xanthium strumarium, by post-emergence application in an emerged crop of mai~e or sorghum.
A similar emulsifiable composition eontaining bromoxynil trimethylamine salt may be prepared as described above by replacing the triethylamine by the appropria~e amount of trimethylamine and used in a similar manner.
* trade marks ~Z~77~;~
- 21 ~
An emulsifiable composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil.. v....O.............................. 34% w/v triethylamine.....~......................... ~ 12.4% w/v Soprophor~ BSU.~............ .................. 5.25% w/v Arylan* CA.................. ................ ~ 2.25% w/v Solvesso* 150,.... 0.. ,............ ,to 100~1o by volume, by mixing together the bromoxynil, the triethylamine and a portion of the Solvesso* 150 with heating and stirring.
The Soprophor* BSU and the Arylan* CA were then added and th~ volume was made up to 100~/o by the addition of Solvesso* 150. The resulting clear brown liquid was self-emulsifying in water and may be diluted with water and applied at a rate of 1.5 litres of emulsi~iable composition in 100 to 300 litres of spray fluid per hectare ~an application rate of 510g of bromoxynil p.e per hectare) to control the growth of broad-leafed weeds, e.g.
Abutilon theophrasti, Amaranthus retro1exus, Chenopodium album, Ipomea pureurea, Poly~onum lapathifolium, Solanum nigrum and X~nthium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
* trade marks .~ .
, o 22 -A wet~able powder containing bromo2ynil triethylamine salt was prepared from:
bromoxynil......... O.............. .. 20% w/w triethylamine.c.O.. ,................ 8~8~/o w/w Soprophor* BSU..... ~..... ~.......... 20 5% w/w diethylene glycol........ ... ........ 10% wlw Aerosil* (silicon dioxîde of microfine particle size~......... to 100% by weight, by mixîng to~ether the bromoxynil, triethylamine ~8u8% w/v of triethylamine represents a 2.5% by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine salt), Soprophor* BSU and diethylene glycol with heating and stirring, until a clear solution of pH9 was obtained. The Aerosil* was then added with stirrin~ until ~he liquid was fully absorbed and a free~flowing powder was obtained which may be diluted with water and applied at a rate of 0~75kg of wettable powder in 100 to 300 litres of spray fluid per hec~are (an application rate of 150g of bromoxynil p.e. per hectare~
* trade marks 7~92 - 23 ~
to control ~he grow~h of broad-leafed weeds, e.g. Abutilon theop rasti, Amaranthus retroflexus, Chenopodium album, Ipomea pur~urea, Polygonum lapathifolium, Solanum ~&~
and Xanthium strumarium, by post-emergence application in an emerged crop of maize or sorghum~ -A similar wettable powder composition containingbromoxynil trimethylamine salt may be prepared as described above by replacing ~he triethylamine by the appropriate amount o trimethylamine and used in a similar manner.
EXA~lPLE 5 Water-dispersible granules containing bromoxynil triethylamine salt were prepared by mixing thoroughly the wettable powder containing bromoxynil triethylamine salt o~tained as described with Example 4 with water (up to 5%
volumelweight) to give a stiff paste or dougb, which was then granulateà by passage through an extruder and removal.
o excess water by drying to give water-dispersible granules which may be diluted with water and applied at a ~te o~ 5kg of water-dispersible granules in 100 t~ 300 litres af spray fluid per hectare (an application rate of lOOOg of bromoxynil p.e. per hectare) to control the growth. of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea . . .
purpurea, Poly~onum lapathifolium, Solanum ni~rum and ~anthium strumarium, by post-emergence applicàtion iD an emerged crop of maize or sorghum.
- ~%~77~2 Similar water-dispersible granules containing bromoxynil trimethylamine salt may be prepared by ~eplacing the triethylamine by the appropriate amount of trimethylamine.
A water-miscible composition containing bromoxynil trimethylamine salt was prepared from:
bromoxynil ~ O~ 34% w/v trimethylamine ~ 7.25% w/v Soprophor* BSU ~ 1.5% w/v tetrahydrofurfuryl alcohol .O....... 25% w/v water ~ to 100% by volume, by mixing together a portion of the water, the tetrahydro-furfuryl alcohol and the bromoxynil with stirring.
Trimethylamine was then bubbled through the solution by means of a dip tube until the pH of the solution was 8Ø
The Soprophor~ BSU was then added and the volum2 was made up to 100% by volume by the addition of water. The resulting clear brown liquid was completely miscible with water and may be diluted with water and applied at 2 rate of 1 litre of water miscible composition in 100 to 300 litres of spray fluid per hectare (an application rate of 340g of bromoxynil p.e. per hectare) to control the growth of broad-leafed weeds, e.g~ Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purpurea~ Poly~onum lapathlEolium, Solanum nigrum and Xanthium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
* trade mark 137~2 ; -- 25 An emulsifiable composition containing bromoxynil trimethylamine salt W3S prepared frsm:
bromoxynil ............... ~................ 34Z w/v trimethylamine ~ 7~25% w/v Soprophor* BSU ~ ........................................ 3.75% wlv Arylan* CA .O......................................... ~ 3.75V~ w/v a 1:1 by volume mixture of cyclohexanone and Solvesso* 150 ~....................... to 100% by volume, by mixing together the bromoxynil and a portion of the cyclohexanone/Solvesso* 150 mixture with heating and stirring. Trimethylamine W2S then bubbled through the solution by means of a dip tube until all the bromoxynil had dissolved. The Soprophor* BSU and Arylan* CA were then added and the volume was then made up to 100% by volume with further cyclohexanone/Solvesso* 150 mixture.
The resulting clear brown li4uid was self-emulsifyin~ in water and may be diluted with water and applied at a rate of l litre oE emulsifiable composition in 100 to 30C
litres of spray fluid per hectare (an application rate of 340g of bromoxynil p.e~ per hectare) to control the growth of Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purpure-a~ Poly~onum lapathifolium, Solanum nigrum and Xanthium strumarium by post-emergence application in an emer~ed crop of maize or sorghum, * trade marks .~
A water-miscible composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ~ 34% w/v (weight/volume) triethylamine ............... ,..... 15% w/v Soprophor* BSU (tristyrylphenol/ethylene oxide condensate containing 18 moles of ethylene oxide ~ O~ 1.5% w/v ~etrahydrofurfuryl alcohol ........ 25% w/v water ~ tO 130% by volume, by mixing together a portion of the water, the tetra-hydrofurfuryl alcohol, the bromoxynil and the triethylamine (15% w~v of triethylamine represents a 2.5%
by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine salt) with hea~ing and stirring. The Soprophor* BSU was then added and the volume was made up to 100% by the addition of water. The resulting clear brown liquid of pH9 was completely miscible with water and may be diluted with water and applied at a rate of 0.5 litres of water miscible composition in 100 to 300 litres o spray fluid per hectare (an application rate of 170g of bromoxynil * trade mark 7~
27 ~
p.e. per hectare) to control the growth of broad-leafed weeds~ e.g. Abuti 10D theophras~i, Amaranthus retroflexus, Chenopodium album, Ipomea purpurea~ Polygonum lapathifolium, Solanum nigrum and Xanthium strumarium, by post-emergence applieation in an emerged crop of maize or scrghum.
An emulsifiable composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ............ ~..... ..34% w/v triethylamine ............... ~ 12.4% w/v Soprophor* BSU ~ 3.75% w/v Arylan* CA .................. ..3.75% w/v a 1:1 by volume mixture of cyclohexanone and Solvesso* 150 ..to 100~ by volume by mixing together a portion of the cyclohexanone/
Solvesso* 150 mixture, the bromoxynil and the ~riethylamin~ with heating and stirring. The Soprophor*
BSU and the Arylan* CA were then added and the volume was made up to 100~/o by the addition of urther cyclohexanone/Solvesso* 150 mixture. The resulting clear brown liquid was self-emulsifiable in water and may be diluted with water and applied at a rate of 1.5 litres of emulsifiable * trade marks .
: ``
, - 2~ -composition in 100 to 300 litres of spray fluid per hectare (an applicat;on rate of 510g of bromoxynil p.eO
per hectare) to control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purp~rea7 Puly~onum r lapatbifolium, Solanum ni~rum and Xanthium strumarium, by post-emergence application iD an emerged crop o~ maize or sorghum.
The method of controlling the growth of we~ds according to the Fresent invention and the advantageous selectivity of bromoxynil trimethyl- and triethyl-amine salts in controlling the growth of broad-leaed weeds in maize and sorghum by post-emergence application, in comparison ~ith the widely-used bromoxynil derivatives bromoxynil octanoate and bromoxynil potassium salt and other amine sa]ts of bromoxynil, is demonstrated in the ollowing experiments.
EXPE~IMENT 1 The fo~lowing formulations were tested:-FormulationA : a water-miscible composition containing 34.0/0 (p.e.
wlv of bromoxynil triethylamine salt, prepared as described in Example 1.
B : fin emusifiable composition containing 34.0~/~ (p.e.) w/v of bromoxynil triethylamine salt, prepared as described in Example 3.
.
., 7~2 , ~ 29 -C : an emulsifiable compositiun containing 34% ~p.e.) w/v ~f bromoxynil ~rie~hylamine salt, prepared as described in Example 2.
D : a water-miscible composition cont~inin~ 34.0% (p.e.) w/v of bromoxynil trimethylamine salt~ prepared as desrribed in Example 1.
E : an emulsifiable composition containin~. 34O9% (p.e.) w/v of bromoxynil trimethylamine salt, prepared as described in Example 2.
F : a water-miscible composition containing 25% (p.e.) w/v of bromoxynil potassium salt, Soprophor* BSU
(1.1% w/v), te~rahydrofurfuryl alcohol (40% w/v) and water (to 100% by volume), prepared by the procedure described in Example 1 but replacing the bromoxynil triethylamine salt and the diethylene glycol by the appropriate amounts of, respectively, bromoxynil potassium salt and tetrahydrofurfuryl alcohol.
G : a commercially available emulsifiable composition containing ?2.5% ~p.e.) w/v of bromoxynil octanoate, a combined total of 7.5% w/v of Atlox* 4855 and Agrilan* A, and High Flash Naphtha CW (a high boiling point petroleum fraction) to 100% by volume, prepared by the general procedure described * trade marks 779:2 in Example ~, using the appropriate quantities of the ingredients indicated above. (Atlox* 4855 and A~rilan* A
are each mixtLJres of nonionic surface active agent and calcium dodecyl benzene sulphonate).
Maize (Zea mays), sorghum (Sorghum bicolor~ and wheat ~Triticum aestivum) plants were grown in the greenhouse by directly sowing seeds in 13cm diameter plastic pots containing John Innes No 1 pottin~ compost (7 parts by volume of sterilized loam, 3 parts by volume of peat and 2 parts by volume of fine grit~.
Weed species were grown from seed in the greenhouse and transplanted at the seedling growth stage into 9cm diameter plastic pots containing John Innes No 1 potting compost. Three maize, sorghum, wheat or weed plants were grown per pot. The mean temperature in the greenhouse ranged rom 15C at night to 27C during the day, with a daylength of 16 hours. Three replicate pots, each containing three plants of uniform growth stage, were used for each spray treatment. Unsprayed pots, each containing three plants of uniform growth, were maintained as * trade marks , .
2~
controls. The plants were at the following growth stages when sprayed:-Plant Leaves Maize 4 Sorghum 3 1/2 Wheat 3 (Broad-leafed Weeds) Amaranthus retroflexus (A.r.~ 3 Poly~onum lapathifolium ~P.l.) 3 Ipomea purpurea (I.p.~ 3 Chenopodium album ~C.a.) 4 Solanum ni~rum (S.a.) 4 : Xanthium strumarium (X.s.) 4 . .
Abutilon theophrasti (A.t.~ 3 15Appropriate quantitie~ of Formulations A to G were diluted in 50mls of water to give spray fluids having : concentrations equivalent to &5, 170, 340, 6~0 and 1360g (p.e.) of bromoxynil per hectare when applied at a spray volume rate of 260 litres p~r hectaré. The treatments were applied to the plants by means of a laboratory spraying apparatus using a flat fan jet ~spray pressure 2.1kgflc.m2), travelling at 2.6km/hour. Aft~r spraying, the pots were returned to the greenhouse and arranged in randomised blocks. The plants were watered by overhead watering 24 hours after spraying and daily tbereafter.
377~
Ten days after spraying, a visual assessment was made of the percentage reduction in top ~rowth of each weed species Eor each replîcate treatment in comparison with untreated control plants. The mean percentage control of each species at each rate of application and the mean precentage overall control o~ all tested weed species was calculated. The results obtained are presented in Table 1 below~
Visual assessment of injury to the maize, sorghum and wheat plants was also made 10 days after spraying and the percentage necrosis of the entire plant was recorded.
These results are given in Table 2 belowO
.
~ 2~)77~;~
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~ . , 1~7792 - 3& -The application ra~e for each of Formulations A to G
required to give 95/O overall control of all weed species was calculated by plotting the overall (all weed ~pecies) percentage controls against application rates on log/probability paper. These application rates giving 95/~
overall weed control are shown`in Table 3 below and : clearly demonstrate that bromoxynmil trimethylamine and triethylamine salts are from 3 to 5 1/2 ~imes more active than bromoxynil potassium salt in controlling tne growh of weeds and that in contrast to : bromoxynil potassium salt3 bromoxynil trimethylamine salt and triethylamine salts are equal to or, at worst, only 1.8 times less active than bromoxynil octanoate in controlling the growth o~ weeds. ;:.
The application rates for each of Formulations A to G which gave no more than 5% of damage (leaf necrosis) to the crop plants (maize, sorghum and wheat~ were similarly calculated from the results given in Table 2. The application rates which gave no more than 5% of damage to the crop plant are also given in Table 3 below.
, .
~2(;~77~2 3~ --The selectivity index ( application rate giving no more than~
5% damage in crop plant application rate giving 95V/o overall J
weed control was calculated from these figures for each formulation in each crop and these indices are also given in Table 3. The selectivity indices clearly demonstrate that bromoxynil trimethylamine and trie~hylam;ne salts are from 2 to 5 1/2 times more selective than bromoxynil octanoate in the control oE broad-leaed weeds by post-emergence application in maize crops, that bromoxynil trimethylamine and triethylamine salts are from 2 1/4 to 6 1/2 times more selective than ~15 bromoxynil octanoate in the control of broad-leafed weeds by post-emergence application ;n sorghum crops and that bromoxynil trimethylamine and triethylamine : . salts are 3 times more active than bromoxyniL
: ~ potassium salt in controlling the growth of broad-leafed weeds by post-emergence applicati5n and a~e more selective than bromoxynil potassium salt in the control of broad-leafed weeds by post-emergence application in maize and sorghum crops. These selectivity indices also indicate that bromoxynil trimethylamine and triethylamine ~alts are highly ' ' .
7~
- - ~,o -selective in wheat but that, in contrast to theix selectivity indices in mai~e and sorghum crops, these salts sho~ no advantage in selectivity over bromoxynil octanoate in controlling the growth of broad-lea~ed weeds by post-emereen e application in wheat.
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7~2 For use i~ the method of con~rolling the growth of broad-leafed weeds according to the present invention, the trimethylamine and ~riethylamine salts of bromoxynil may be applied in herbicidal compositions comprising at.least one of the trimethyl-amine and triethylamine salts of bromoxynil in association with, and preferably homogeneously dispersed in, one or more compatible herbicidally-acceptable diluents or carriers or surface-ac~ive agen,s (i.e. diluents or carriers or surface-active agents of the ~ype generally accep~ed in the art as being sui~able for use in herbicîdal compositions and which are compatible with the bromoxynil trimethyl-. and triethyl-amine salts). The term "homogeneously......... .. .
dispersed" is used to include compositions in which the bromoxynil trimethyl- and triethyl-amine salts are dissolved in the other components. The term "herbicidal compositions" is used in a broad sense to include not only compositions which are ready for use 2D as herbicides but also concentrates which must be diluted before ~se. Preferably, the compositions contain from 0.05 to 90~ by weight of at least one of the trim~hylamine and triethylamine salts of bromoxynil.
The herbicidal compositions may contain both a diluent or carrier and a surface-active (e.g. wetting, dispersingJ or emulsiying) agent. Surface-active agents which may be present in herbicidal compositions used in the present invencion may be of the ionic or non-ionic types, for example sulphoricinoleates, quaternary ammonium derivatives, products based on condensates of ethylene oxide ~ith alkyl, e.g. nonyl or octyl, vr polyaryl phenols, or carboxylic acid 1~ es~ers of anhydrosorbitols which have been rendered soluble by etheri~ication of the free hydroxy groups by condensation with ethylene oxide, alkali and alkaline earth salts o~` sulphuric acid esters and sulphonic acids such as dinonyl- and dioctyl-sodium sulphono-succinates, alkali and alkaline earth metal salts of high molecular weight sulphonic acid derivatives such as sodium and calcium lignosulphonates and sodium and calcium alkyl benzen~
sulphonates.
Suitably, her~icidal compositions may comprise from 0.01 to 10~/~ by weight of surface-~tive agent but, if desired, herbicidal compositions used in the present invention may comprise higher proportions of surface-active agent, or example up ~o 15% in liquid emulsifiable suspension concentrates and up to 25% in liquid water soluble concentrates.
%
Examples of suitable solid diluents or carriers are aluminium silicate, talc, calcined magnesia, kieselguhr, tricalcium phosphate, powdered cork, adsorbent carbon black and elays such as kaolin and ben~onite. Th~ solid compositions (which may ~ake tbe form of dusts, granules or wettable powders~ are preferably prepared by grinding the brom~xynil trimethyl- and triethyl-amine salts with solid diluents or by impregnating the solid diluents or carriers with solutions of the bromoxynil trimethyl-and triethyl-amine salts in vola~ile solvents, evaporating thP solvents and, i~ necessary, grinding the products so as to obtain powdersO Granular formulations may be p~epared by absorbing the bromoxynil trimethyl- and triethyl-amine salts (dissolved in suitable solvents) onto ~he solid diluents or carriers in granular form and, i necessary, re~oving excess solvent, e~g. by evaporation, or by granulating compositions in powder 2~ form obtained as described above Solid herbicidal compositions, particularly wettable powders and granules, may contain wetting or dispersing agent (for example of the types described above), which may also, when solid, serve as diluents or carriersO
~77~2 Liquid compositions may take the form of aqueous, organic or aqueous-organic solutions, suspensions and emulsions which may incorporate a surace-actiYe agent. Suita~le liquid diluents for incorporation in the liquid compositions include water, glycols, tetrahydrofurfuryl alcohol, acetophenone, cyclohexanone, isophorone, tolueDe, xylene and mineral, animal and vegetable oils, e.g.
light aromatic and naphthenic pe~roleum fractions (and mixtures of these diluents). Surface-active agents, which may be present in the liquid compositions, may be icnic or non-ionic (for example of the types described above) and may, when liquid, also serve as diluents or carriersO -Wettable powders, dispersible granules and liq~id compositions in the form of concentratés may be diluted ~ith water or other suitable diluents, fo.
example mineral or vegetable oils 9 particularly in the case of liquid concentrates in which the diluent or carrier is an oil, to give compositions ready foruse. When desired, liquid compositions of the bromoxynil trimethyl- and triethyl-amine salts may be used in the form of self-emulsifying concentrates compris.ing the active s~bstances dissolved in the emulsifying agents or in solvents containing emulsifying agents compatible wi~h the active substances, the si~ple ~ 7~ ~ .
addition of such concentrates to water producing compositions ready for useO
Liquid concentrates in which the diluent or carrier is an oil may b used without fur~her dilu~ion using the electrostatio spray technique.
Herbicidal compositions may also contaiD~ if desired, conventional adjuvants such as adhesives~
protective colloids~ thickeners, penetrating agen~s, st~bilisers, sequesterin~ agen~s, anti-caking agen~s~
colouring agents and corrosion inhibitors. These adjuvants may also serve as carriers or diluents.
Preferred herbieidal compositions are wettablc powders which comprise from 10 to 90~/O w~w of at least one of the trimethylamîne and triethylamine salts of bromoxynil, from 2 to 10% w/w of surface-active agent and rom 10 to 88% w/w of solid diluent or carrier;
liquid water-miscible concentrates which comprise from 5 to 50% w/v o~ at least one o the trimethylamine and triethylamine salts of bromoxynil9 from 5 to 25UZ wlv o~ surface-active agent and from 25 to 90~/O by volume of water-miscible solvent~ e.g. dimethylformamide, or a mixt~lre of water-miscible solvent and wa~er;
granules which comprise from 1 to 90% wlw of at least one of the trimethyla~ine and triethylamine salts of bromoxynil, from 0.5 to 2.5% w/w of surface-active agent and from 7.5 to g8~5~/o w/w of granular c~rrier, 7~2 and emulsifiable concen~rates which comprise from 0.05 to ~OV/o wJv, and preferably from 1 to 60~/~ w/v, of at least one ~f the trimethylamine and triethylamine salts of bromoxynil, ~rom 0.01 to 10~/~ w/v, and preferably ~rom 1 to 10% wlv, of surface-active agent and from 9.99 to 99.~4%, and preferably from 39 to 58.99~/~, by volume of organic solvent.
Herbicidal compositions may also comprise the bromoxynil trimethyl- and triethyl-amine sal~s in association with, and preferably homogeneously dispersed in, one or more other herbicides as hereînbefore described which may be used in conjunction with the trimethylamine and triethylamine salts o~ bromoxynil and, if desired one or more compatible pesticidally accep~able diluents or carriers, surface-active agents and conventional adjuvants as hereinbefore described.
The bromoxynil trimethyl- and ~riethyl-amine salts may be prepared by reacting stoichiometric amounts of bromoxynil and trimethylamine or triethylamine in a suitable inert solvent, for example a liquid diluent suitable for incorporation in liquid herbicidal compositions used in the present invention as hereinbefore described, or mixtures thereof, or a lower aliphatic alcohol, e.g. methanol . ^ ` ,, , ~ .
or ethanol, or acetone, if necessary with heating. If desiredl a stoichiometric amount of a mixture of trimethylamine and triethylamine may be used~ The bromoxynil trimethyl- and triethyl-amine salts or mixtures thereof may, 5 if desired, be iso~ated from the reaction mixture by conventional methods, for example by filtration, if necessary after the partial or complete removal of the solvent, e.g. by evaporation. However, it i5 frequently more convenient to use the solution of the trimethylamine or triethylamine salts 10 or ~romoxynil or mixtures thereof in a solvent which is obtained directly in the preparation of herbicidal compositions used in the present invention, particularly liquid herbicidal compositions, withou~ isolating the bromoxynil trimethyl- and triethylamine salts. When reacting 15 bromoxynil with trimethylamine or triethylamine or mixtures thereof in a solvent to give a solution of the trimethylamine or triethylamine salt of bromoxynil or mixtures thereof suitable for use directly in the preparation of herbicidal compositions, more especially liquid water-miscible 20 concentrates and wettable powders, according to the present invention, without isolation of the bromoxynil trimethyl- and triethyl-amine salts or mixtures thereof, it is preferred to use a slight excess of trimethylamine or triethylamine or mixture thereof over the stoichiometric amount in order to 25 give a solution o pH8.5 to pH9.5. If desired other components of herbicidal compositions, for example surface j~,^` ', ~2077g?
active agents, may be included in the solvent in which the trimethylamine or triethylamine salt of bromoxynil or mixtures thereof is prepared.
Bromoxynil triethylamine salt is a new compound 5 which, together with its process of preparation form further features of the present invention. When a herbicidal composition comprises bromoxynil triethylamine salt and water or a common organic solvent a surface active agent is preferably present.
7~2 _ ~8 -The Eollowing Examples illustrate herbicidal compositions used in the present invention.
A water-miscible composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ..................... 34% w/v (weight/volume) triethylamine .................. 15% w/v Soprophor* BSU (tristyrylphenol/ethylene oxide condensate containing 18 moles of e~hylene oxide ......... 1.5% w1v diethylene glycol ............ ,. 25% wfv water .................... to 100% by volume, by mixing together a portion of the water, the diethylene glycol, the bromoxynil and the triethylamine (15~/~ w/v of triethylamine represents a ~.6V/o by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine sal~) with heating and stirring. The Soprophor* BSU was then added and the volume was made up to 100% by the addition of water. The resulting clear brown liquid of pH9 was completely miscible with water and may be diluted with water and applied at a rate of 0.5 litres of water miscible composition in 100 to 300 li~res of spray fluid per * trade mark ~ ` J
7~
~ 9 hectare ~an application rate of 170g of bromoxynil p.e.
per hectare) ~o control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Cheno~od_um album, Ipomea ~purea, Polygonum lapathifolium, Solanum ni~rum and Xan~hium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
A similar water-miscible composi~ion containing bromoxynil trimethylamine salt may be prepared as described above by replacing the tr;ethylamine by the appropria~e amount of trimethylamine and used in a similar manner.
An emulsifi~ble composi~ion containing bromoxynil triethylamine salt was prepared from:
bromoxynil ~ 34% w/v triethylamine .................... 12.4% w/v Soprophor* BSU .........~........ ~.5.25% w/v Arylan* CA (70~/O solution of calcium dodecyl benzene sulphonate).. 2.25% w/v cyclohexanone ................ ... 7.5~lO ~/v (volume/volume) Solvesso* 150 (aromatic C10 fraction of petroleum) to 100% by volume, trade marks ~7~7~
, ., ~ 2~
by mixing together the cyclohexanone, the bromoxynil and ~he triethylamine and a portion of the Solvesso* 150 with heating and stirring. The Soprophor* BSU and the Arylan*
CA were then added and the volume was made up to 100% by the addition of Solvesso* 150. The resulting clear brown liquid was self-emulsifiable in water and may be diluted with water and applied at a rate of 1.5 litres of emulsifiable composition in 100 to 300 litres of spray ~luid per hectare (an application rate of 510g of bromoxynil p.e. per hectare) to control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retrof _ us, Chenopodium album, I~omea purpurea, Poly~onum lapathifolium, Solanum nigrum and Xanthium strumarium, by post-emergence application in an emerged crop of mai~e or sorghum.
A similar emulsifiable composition eontaining bromoxynil trimethylamine salt may be prepared as described above by replacing the triethylamine by the appropria~e amount of trimethylamine and used in a similar manner.
* trade marks ~Z~77~;~
- 21 ~
An emulsifiable composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil.. v....O.............................. 34% w/v triethylamine.....~......................... ~ 12.4% w/v Soprophor~ BSU.~............ .................. 5.25% w/v Arylan* CA.................. ................ ~ 2.25% w/v Solvesso* 150,.... 0.. ,............ ,to 100~1o by volume, by mixing together the bromoxynil, the triethylamine and a portion of the Solvesso* 150 with heating and stirring.
The Soprophor* BSU and the Arylan* CA were then added and th~ volume was made up to 100~/o by the addition of Solvesso* 150. The resulting clear brown liquid was self-emulsifying in water and may be diluted with water and applied at a rate of 1.5 litres of emulsi~iable composition in 100 to 300 litres of spray fluid per hectare ~an application rate of 510g of bromoxynil p.e per hectare) to control the growth of broad-leafed weeds, e.g.
Abutilon theophrasti, Amaranthus retro1exus, Chenopodium album, Ipomea pureurea, Poly~onum lapathifolium, Solanum nigrum and X~nthium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
* trade marks .~ .
, o 22 -A wet~able powder containing bromo2ynil triethylamine salt was prepared from:
bromoxynil......... O.............. .. 20% w/w triethylamine.c.O.. ,................ 8~8~/o w/w Soprophor* BSU..... ~..... ~.......... 20 5% w/w diethylene glycol........ ... ........ 10% wlw Aerosil* (silicon dioxîde of microfine particle size~......... to 100% by weight, by mixîng to~ether the bromoxynil, triethylamine ~8u8% w/v of triethylamine represents a 2.5% by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine salt), Soprophor* BSU and diethylene glycol with heating and stirring, until a clear solution of pH9 was obtained. The Aerosil* was then added with stirrin~ until ~he liquid was fully absorbed and a free~flowing powder was obtained which may be diluted with water and applied at a rate of 0~75kg of wettable powder in 100 to 300 litres of spray fluid per hec~are (an application rate of 150g of bromoxynil p.e. per hectare~
* trade marks 7~92 - 23 ~
to control ~he grow~h of broad-leafed weeds, e.g. Abutilon theop rasti, Amaranthus retroflexus, Chenopodium album, Ipomea pur~urea, Polygonum lapathifolium, Solanum ~&~
and Xanthium strumarium, by post-emergence application in an emerged crop of maize or sorghum~ -A similar wettable powder composition containingbromoxynil trimethylamine salt may be prepared as described above by replacing ~he triethylamine by the appropriate amount o trimethylamine and used in a similar manner.
EXA~lPLE 5 Water-dispersible granules containing bromoxynil triethylamine salt were prepared by mixing thoroughly the wettable powder containing bromoxynil triethylamine salt o~tained as described with Example 4 with water (up to 5%
volumelweight) to give a stiff paste or dougb, which was then granulateà by passage through an extruder and removal.
o excess water by drying to give water-dispersible granules which may be diluted with water and applied at a ~te o~ 5kg of water-dispersible granules in 100 t~ 300 litres af spray fluid per hectare (an application rate of lOOOg of bromoxynil p.e. per hectare) to control the growth. of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea . . .
purpurea, Poly~onum lapathifolium, Solanum ni~rum and ~anthium strumarium, by post-emergence applicàtion iD an emerged crop of maize or sorghum.
- ~%~77~2 Similar water-dispersible granules containing bromoxynil trimethylamine salt may be prepared by ~eplacing the triethylamine by the appropriate amount of trimethylamine.
A water-miscible composition containing bromoxynil trimethylamine salt was prepared from:
bromoxynil ~ O~ 34% w/v trimethylamine ~ 7.25% w/v Soprophor* BSU ~ 1.5% w/v tetrahydrofurfuryl alcohol .O....... 25% w/v water ~ to 100% by volume, by mixing together a portion of the water, the tetrahydro-furfuryl alcohol and the bromoxynil with stirring.
Trimethylamine was then bubbled through the solution by means of a dip tube until the pH of the solution was 8Ø
The Soprophor~ BSU was then added and the volum2 was made up to 100% by volume by the addition of water. The resulting clear brown liquid was completely miscible with water and may be diluted with water and applied at 2 rate of 1 litre of water miscible composition in 100 to 300 litres of spray fluid per hectare (an application rate of 340g of bromoxynil p.e. per hectare) to control the growth of broad-leafed weeds, e.g~ Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purpurea~ Poly~onum lapathlEolium, Solanum nigrum and Xanthium strumarium, by post-emergence application in an emerged crop of maize or sorghum.
* trade mark 137~2 ; -- 25 An emulsifiable composition containing bromoxynil trimethylamine salt W3S prepared frsm:
bromoxynil ............... ~................ 34Z w/v trimethylamine ~ 7~25% w/v Soprophor* BSU ~ ........................................ 3.75% wlv Arylan* CA .O......................................... ~ 3.75V~ w/v a 1:1 by volume mixture of cyclohexanone and Solvesso* 150 ~....................... to 100% by volume, by mixing together the bromoxynil and a portion of the cyclohexanone/Solvesso* 150 mixture with heating and stirring. Trimethylamine W2S then bubbled through the solution by means of a dip tube until all the bromoxynil had dissolved. The Soprophor* BSU and Arylan* CA were then added and the volume was then made up to 100% by volume with further cyclohexanone/Solvesso* 150 mixture.
The resulting clear brown li4uid was self-emulsifyin~ in water and may be diluted with water and applied at a rate of l litre oE emulsifiable composition in 100 to 30C
litres of spray fluid per hectare (an application rate of 340g of bromoxynil p.e~ per hectare) to control the growth of Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purpure-a~ Poly~onum lapathifolium, Solanum nigrum and Xanthium strumarium by post-emergence application in an emer~ed crop of maize or sorghum, * trade marks .~
A water-miscible composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ~ 34% w/v (weight/volume) triethylamine ............... ,..... 15% w/v Soprophor* BSU (tristyrylphenol/ethylene oxide condensate containing 18 moles of ethylene oxide ~ O~ 1.5% w/v ~etrahydrofurfuryl alcohol ........ 25% w/v water ~ tO 130% by volume, by mixing together a portion of the water, the tetra-hydrofurfuryl alcohol, the bromoxynil and the triethylamine (15% w~v of triethylamine represents a 2.5%
by weight excess of triethylamine over the stoichiometric amount required to form bromoxynil triethylamine salt) with hea~ing and stirring. The Soprophor* BSU was then added and the volume was made up to 100% by the addition of water. The resulting clear brown liquid of pH9 was completely miscible with water and may be diluted with water and applied at a rate of 0.5 litres of water miscible composition in 100 to 300 litres o spray fluid per hectare (an application rate of 170g of bromoxynil * trade mark 7~
27 ~
p.e. per hectare) to control the growth of broad-leafed weeds~ e.g. Abuti 10D theophras~i, Amaranthus retroflexus, Chenopodium album, Ipomea purpurea~ Polygonum lapathifolium, Solanum nigrum and Xanthium strumarium, by post-emergence applieation in an emerged crop of maize or scrghum.
An emulsifiable composition containing bromoxynil triethylamine salt was prepared from:
bromoxynil ............ ~..... ..34% w/v triethylamine ............... ~ 12.4% w/v Soprophor* BSU ~ 3.75% w/v Arylan* CA .................. ..3.75% w/v a 1:1 by volume mixture of cyclohexanone and Solvesso* 150 ..to 100~ by volume by mixing together a portion of the cyclohexanone/
Solvesso* 150 mixture, the bromoxynil and the ~riethylamin~ with heating and stirring. The Soprophor*
BSU and the Arylan* CA were then added and the volume was made up to 100~/o by the addition of urther cyclohexanone/Solvesso* 150 mixture. The resulting clear brown liquid was self-emulsifiable in water and may be diluted with water and applied at a rate of 1.5 litres of emulsifiable * trade marks .
: ``
, - 2~ -composition in 100 to 300 litres of spray fluid per hectare (an applicat;on rate of 510g of bromoxynil p.eO
per hectare) to control the growth of broad-leafed weeds, e.g. Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purp~rea7 Puly~onum r lapatbifolium, Solanum ni~rum and Xanthium strumarium, by post-emergence application iD an emerged crop o~ maize or sorghum.
The method of controlling the growth of we~ds according to the Fresent invention and the advantageous selectivity of bromoxynil trimethyl- and triethyl-amine salts in controlling the growth of broad-leaed weeds in maize and sorghum by post-emergence application, in comparison ~ith the widely-used bromoxynil derivatives bromoxynil octanoate and bromoxynil potassium salt and other amine sa]ts of bromoxynil, is demonstrated in the ollowing experiments.
EXPE~IMENT 1 The fo~lowing formulations were tested:-FormulationA : a water-miscible composition containing 34.0/0 (p.e.
wlv of bromoxynil triethylamine salt, prepared as described in Example 1.
B : fin emusifiable composition containing 34.0~/~ (p.e.) w/v of bromoxynil triethylamine salt, prepared as described in Example 3.
.
., 7~2 , ~ 29 -C : an emulsifiable compositiun containing 34% ~p.e.) w/v ~f bromoxynil ~rie~hylamine salt, prepared as described in Example 2.
D : a water-miscible composition cont~inin~ 34.0% (p.e.) w/v of bromoxynil trimethylamine salt~ prepared as desrribed in Example 1.
E : an emulsifiable composition containin~. 34O9% (p.e.) w/v of bromoxynil trimethylamine salt, prepared as described in Example 2.
F : a water-miscible composition containing 25% (p.e.) w/v of bromoxynil potassium salt, Soprophor* BSU
(1.1% w/v), te~rahydrofurfuryl alcohol (40% w/v) and water (to 100% by volume), prepared by the procedure described in Example 1 but replacing the bromoxynil triethylamine salt and the diethylene glycol by the appropriate amounts of, respectively, bromoxynil potassium salt and tetrahydrofurfuryl alcohol.
G : a commercially available emulsifiable composition containing ?2.5% ~p.e.) w/v of bromoxynil octanoate, a combined total of 7.5% w/v of Atlox* 4855 and Agrilan* A, and High Flash Naphtha CW (a high boiling point petroleum fraction) to 100% by volume, prepared by the general procedure described * trade marks 779:2 in Example ~, using the appropriate quantities of the ingredients indicated above. (Atlox* 4855 and A~rilan* A
are each mixtLJres of nonionic surface active agent and calcium dodecyl benzene sulphonate).
Maize (Zea mays), sorghum (Sorghum bicolor~ and wheat ~Triticum aestivum) plants were grown in the greenhouse by directly sowing seeds in 13cm diameter plastic pots containing John Innes No 1 pottin~ compost (7 parts by volume of sterilized loam, 3 parts by volume of peat and 2 parts by volume of fine grit~.
Weed species were grown from seed in the greenhouse and transplanted at the seedling growth stage into 9cm diameter plastic pots containing John Innes No 1 potting compost. Three maize, sorghum, wheat or weed plants were grown per pot. The mean temperature in the greenhouse ranged rom 15C at night to 27C during the day, with a daylength of 16 hours. Three replicate pots, each containing three plants of uniform growth stage, were used for each spray treatment. Unsprayed pots, each containing three plants of uniform growth, were maintained as * trade marks , .
2~
controls. The plants were at the following growth stages when sprayed:-Plant Leaves Maize 4 Sorghum 3 1/2 Wheat 3 (Broad-leafed Weeds) Amaranthus retroflexus (A.r.~ 3 Poly~onum lapathifolium ~P.l.) 3 Ipomea purpurea (I.p.~ 3 Chenopodium album ~C.a.) 4 Solanum ni~rum (S.a.) 4 : Xanthium strumarium (X.s.) 4 . .
Abutilon theophrasti (A.t.~ 3 15Appropriate quantitie~ of Formulations A to G were diluted in 50mls of water to give spray fluids having : concentrations equivalent to &5, 170, 340, 6~0 and 1360g (p.e.) of bromoxynil per hectare when applied at a spray volume rate of 260 litres p~r hectaré. The treatments were applied to the plants by means of a laboratory spraying apparatus using a flat fan jet ~spray pressure 2.1kgflc.m2), travelling at 2.6km/hour. Aft~r spraying, the pots were returned to the greenhouse and arranged in randomised blocks. The plants were watered by overhead watering 24 hours after spraying and daily tbereafter.
377~
Ten days after spraying, a visual assessment was made of the percentage reduction in top ~rowth of each weed species Eor each replîcate treatment in comparison with untreated control plants. The mean percentage control of each species at each rate of application and the mean precentage overall control o~ all tested weed species was calculated. The results obtained are presented in Table 1 below~
Visual assessment of injury to the maize, sorghum and wheat plants was also made 10 days after spraying and the percentage necrosis of the entire plant was recorded.
These results are given in Table 2 belowO
.
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~ . , 1~7792 - 3& -The application ra~e for each of Formulations A to G
required to give 95/O overall control of all weed species was calculated by plotting the overall (all weed ~pecies) percentage controls against application rates on log/probability paper. These application rates giving 95/~
overall weed control are shown`in Table 3 below and : clearly demonstrate that bromoxynmil trimethylamine and triethylamine salts are from 3 to 5 1/2 ~imes more active than bromoxynil potassium salt in controlling tne growh of weeds and that in contrast to : bromoxynil potassium salt3 bromoxynil trimethylamine salt and triethylamine salts are equal to or, at worst, only 1.8 times less active than bromoxynil octanoate in controlling the growth o~ weeds. ;:.
The application rates for each of Formulations A to G which gave no more than 5% of damage (leaf necrosis) to the crop plants (maize, sorghum and wheat~ were similarly calculated from the results given in Table 2. The application rates which gave no more than 5% of damage to the crop plant are also given in Table 3 below.
, .
~2(;~77~2 3~ --The selectivity index ( application rate giving no more than~
5% damage in crop plant application rate giving 95V/o overall J
weed control was calculated from these figures for each formulation in each crop and these indices are also given in Table 3. The selectivity indices clearly demonstrate that bromoxynil trimethylamine and trie~hylam;ne salts are from 2 to 5 1/2 times more selective than bromoxynil octanoate in the control oE broad-leaed weeds by post-emergence application in maize crops, that bromoxynil trimethylamine and triethylamine salts are from 2 1/4 to 6 1/2 times more selective than ~15 bromoxynil octanoate in the control of broad-leafed weeds by post-emergence application ;n sorghum crops and that bromoxynil trimethylamine and triethylamine : . salts are 3 times more active than bromoxyniL
: ~ potassium salt in controlling the growth of broad-leafed weeds by post-emergence applicati5n and a~e more selective than bromoxynil potassium salt in the control of broad-leafed weeds by post-emergence application in maize and sorghum crops. These selectivity indices also indicate that bromoxynil trimethylamine and triethylamine ~alts are highly ' ' .
7~
- - ~,o -selective in wheat but that, in contrast to theix selectivity indices in mai~e and sorghum crops, these salts sho~ no advantage in selectivity over bromoxynil octanoate in controlling the growth of broad-lea~ed weeds by post-emereen e application in wheat.
:
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. .
EXP~RIM~NT 2 The following formulations were ~ested:-Formulation : H : a water-miscible composition containing 34.0%
(p.e.) wlv of bromoxynil trimethylamine salt, prepared as described in F.xample 6.
:.
I : an emuslfiable composition cvntaining 34,0/0 (p.e.) w/v of bromoxynil trimethylamine salt, prepared as described in Example 7 J : a water-miscible composition containing 34.0V/~
(p.e.) wlv of bromoxynil triethylamine salt, : prepared as described in Example 8.
K : an emusifiable composition containing 34.0%
p.e.) w/~ of bromoxynil trie~hylamine salt, ;
prepared as described in Example 9.
L : a water-miscible composition containing 34.0%
(p.e.) w/v of bromoxynil triethanolamine salt, prepared by the procedure described in Example 8 but replacing the triethylamine by the . 20 app~opriate stoichiometric amount of triethanolamine.
~l : an emusifiabl~ composition containing 34.0~O
(p.e.) w/v of bromc~xynil tri-n-propylamine salt, prepared by the procedure ~escribed in Example 9 but replacing the triethylamine by ~he . appropriate stoichiometric amount of tri-n-propylamine.
, ~()7~7 - 4 '~ -.
N : an emusifiable composition containing 34.0~/O
(p.e.) w/v of bromoxynil tri-n-butylamine salt, prepared by thc procedure described in Example 9 but replacing the triethylamine by the appropriate stoichiometric amount oE tri-n-butylamine.
0 : an emusifiable composition containing 34.0'J/O
(p.e.) w/v of bromoxynil methyl-di-n-octyl-amine salt, prepared by the procedure described in Example 9 but replacing the triethylamine by the appropriate stoichiometric amount of methyl-; di-n-octylamine.
P : a water-miscible composition containing 17.0%
(p O e.) w/v of bromoxynil potassium salt, prepar~d by the procedure described in ExampIe 8 but replacing the bromoxynil and the triethylamine by the appropriate amount of bromoxynil potassium salt.
Q : a water-miscible composition containing 17~0~/o ~,~ (p.e,~ w/v of bromoxynil ammonium salt, prepared by the procedure described in Example 8 but replacing the triethylamine by concentrated ~queous ammonia and using the appropriate stoichiometric amounts of bromoxynil and ammonia.
, .
~2~77 ', 5 R : an emusifiable composition containing 34.0/O
(p.e.) w/v of bromoxynil octanoate, prepared by the procedure described in Example 9 but replacing the bromoxynil and the triethylamine by the appropriate amount of bromoxynil octanoate.
Maize, sorghum and broad leafed weeds were grown in ~he green house as described in Experiment 1. The plants were at the following growth stages when sprayed:-10 Crop Plants Leaves Maize 3 Sorghum 3 Weeds Ipomea purpu~ea (I.p.)cotyledons ~ 1 true leaf ~: - ... ,.... .. I
Abutilon theophrasti (A~t.) cotyledons ~ 1 true leaf Amaranthus retroflexus (A 4 r.) 2 Chenopodium album ~C.a.) 4 Appropriate quantities of Formulations H to R were diluted in 50mls of water to give spray fluids having concentrations equivalent to 85, 170, 3403 680 and - 1360g (p.e.) of bromoxynil per hectare when appli~d at a spray ~olume rate oE 260 litres per hectare. The treatments were applied as described in F.xperiment 1 Un~:prayed pots were maintained as controls.
- ~6 ~
Ten days after spraying, a visual assess~ent was made of the percentage reduction in top growth of each weed species for ~ach replicate treatmen~ in comparison with untreated control plants. The mean percentage control of each species at each rate o~
application and the mean percentage overall control of all tested weed species was calculated. The results obtained are presented in Table 4 below.
Visual assessment of injury to ~he maize and sorghum plants was also made 10 days after spraying and tbe percentage necrosis o~ the Pntire plan~ was recorded. These results are gi~en in Table 5 below.
.
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The application rate for each of ~ormulat;ons H to R
~equired to give 95% overall control of all weed species tested was calculated as described in Experiment 1. These application rates giving 95% overall weed control are shown in Table 6 below and clearly demonstrate that bromoxynil trimethylamine and triethylamine salts are more ac~ive than bromoxynil triethanolamine, tri-n-propylamine, tri~n-butylamine and methyl-di-n octylamine salts, from 3 1/~ to 4 times more active than bromoxynil potassium salt and from ~ to 3 times more active than bromoxynil a~monium sal~, in control3.ing the gro~h o broad-leafed weeds by post-emergence applicationO Bromoxynil trimethylamine and triethylamine salts are shown to approach more closely the high level of activity shown by bromoxynil octanoate in controlling the growth of broad-lea~ed weeds by post-emergence applicationl than the other bromoxynil salts tested, and in particular bro~oxynil potassium and am~onium salts, bromoxynil trimethylamine and trimethylamine salts being at ~orst only 1.6 times less active than bromoxynil octanoate in controlling the growth of weeds, whereas~ in eontrast~
bromoxynil potassium and ammonium salts are less than 5 1/2 times and less than 4 times~ respectively, as actiYe as bromoxynil octanoa~eO
~2~7~Z
-- 5', The application rates or each oE Formulations H to R which gave no more than 5% of damage (lea~ necrosis) to the crop plants (maize and sorghum) were similar~y calculated from the results given in Table S and are also ~: 5 shown in TabLe 6 below. The selectivity index was calculated from these figure or each formulation in each crop and these indices are also ~iven in Table 6. The selectivity indices clearly demonstrate that bromoxynil ~: trimethylamine and trieth~lamine salts are highly selective in maize and sorghum, in contrast to bromoxynil triethanolamine, tri-n~propylamine, tri-n-butylamine, methyl-di-n-octylamine, ammonium and potassium salts and-bromoxynil octanoate. The selectivity indices indicate : that bromoxynil trimethylamine and triethylamine salts are from 2~5 to 3,3 times more selective than bromoxynil octanoate in the control of broad-leafed weeds by post-emergence application in maize crops and that bromoxynil trimethyiamine and triethylamine sal~s are from 2.8 to 3.1 times more selective than bromoxynil octanoate in the control of broad~leafed weeds by post~emergence application in sorghum crops. These selectivity indices also indicate that bromoxynil triethanolamine, tri-n-propylamine, tri-n-butylamine, methyl-di-n-octylamine, ammonium ard potassium salts show no advantage in selectivity over bromoxynil octanoate in controlling the growth of broad-leafed weeds by post-emergence applicaton in maize and sorghum crops.
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~ 58 -The following ~xample illu6trcltes the preparation of bromoxynil trimethyl- and triethyl-amine salts.
_XA~IPLE 10 Triethylamine (5.50ml~ was added to a stirred solution oE 3,5~dibromo-4-hydroxybenzonitrile (5.54g) in acetone (40ml). After 10 minutes, when ~he exothermic reaction had subsided, the mixture was filtered and the filtrate was evaporated to dryness to lQ give a solid. The solid ~hus obtained was triturated with ethyl acetate and separated by filtration to give bromoxynil triethylamine salt (which may be - . , alternatively named as tri thylam~,onium 2,6-dibromo-4-cyanophenoxide) (5.1g), in the form of a cream i ~ . ' ,. ~j .~. . !
coloured s~lid, m.p.56-58C LElemental analysis:-C,41.20;H,4.8Q;N,7.30%; calculated for C13H1gBr2N20:- C,41.30;H,4.76jN,7.40~/o3.
By proceeding in a similar manner but replacing the triethylamine by trimetnylamine and the ?~ceton2 by etha~ol, there was ob~ained bromoxynil trimethylami~e salt ~which may be alternatively named as ~rimethyl-ammonium 2,6-dibromo-4-cyan~phenoxide) in the form of a cream coloured solid, m.p. 97-99C lElemental analysis:- C~35~3;H~3~4;N~7~6~/o; calculated for 2~ ~1oH12Br2N~O:-C,35.7;H,3.6;N,8.3tO]~
3J5-Dibromo-4-hydroxybenzonitrile (bromoxynil~
may be prepared as described by Auwers and Reis, Ber., 2g (2~, 2355-2360 (1896).
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EXP~RIM~NT 2 The following formulations were ~ested:-Formulation : H : a water-miscible composition containing 34.0%
(p.e.) wlv of bromoxynil trimethylamine salt, prepared as described in F.xample 6.
:.
I : an emuslfiable composition cvntaining 34,0/0 (p.e.) w/v of bromoxynil trimethylamine salt, prepared as described in Example 7 J : a water-miscible composition containing 34.0V/~
(p.e.) wlv of bromoxynil triethylamine salt, : prepared as described in Example 8.
K : an emusifiable composition containing 34.0%
p.e.) w/~ of bromoxynil trie~hylamine salt, ;
prepared as described in Example 9.
L : a water-miscible composition containing 34.0%
(p.e.) w/v of bromoxynil triethanolamine salt, prepared by the procedure described in Example 8 but replacing the triethylamine by the . 20 app~opriate stoichiometric amount of triethanolamine.
~l : an emusifiabl~ composition containing 34.0~O
(p.e.) w/v of bromc~xynil tri-n-propylamine salt, prepared by the procedure ~escribed in Example 9 but replacing the triethylamine by ~he . appropriate stoichiometric amount of tri-n-propylamine.
, ~()7~7 - 4 '~ -.
N : an emusifiable composition containing 34.0~/O
(p.e.) w/v of bromoxynil tri-n-butylamine salt, prepared by thc procedure described in Example 9 but replacing the triethylamine by the appropriate stoichiometric amount oE tri-n-butylamine.
0 : an emusifiable composition containing 34.0'J/O
(p.e.) w/v of bromoxynil methyl-di-n-octyl-amine salt, prepared by the procedure described in Example 9 but replacing the triethylamine by the appropriate stoichiometric amount of methyl-; di-n-octylamine.
P : a water-miscible composition containing 17.0%
(p O e.) w/v of bromoxynil potassium salt, prepar~d by the procedure described in ExampIe 8 but replacing the bromoxynil and the triethylamine by the appropriate amount of bromoxynil potassium salt.
Q : a water-miscible composition containing 17~0~/o ~,~ (p.e,~ w/v of bromoxynil ammonium salt, prepared by the procedure described in Example 8 but replacing the triethylamine by concentrated ~queous ammonia and using the appropriate stoichiometric amounts of bromoxynil and ammonia.
, .
~2~77 ', 5 R : an emusifiable composition containing 34.0/O
(p.e.) w/v of bromoxynil octanoate, prepared by the procedure described in Example 9 but replacing the bromoxynil and the triethylamine by the appropriate amount of bromoxynil octanoate.
Maize, sorghum and broad leafed weeds were grown in ~he green house as described in Experiment 1. The plants were at the following growth stages when sprayed:-10 Crop Plants Leaves Maize 3 Sorghum 3 Weeds Ipomea purpu~ea (I.p.)cotyledons ~ 1 true leaf ~: - ... ,.... .. I
Abutilon theophrasti (A~t.) cotyledons ~ 1 true leaf Amaranthus retroflexus (A 4 r.) 2 Chenopodium album ~C.a.) 4 Appropriate quantities of Formulations H to R were diluted in 50mls of water to give spray fluids having concentrations equivalent to 85, 170, 3403 680 and - 1360g (p.e.) of bromoxynil per hectare when appli~d at a spray ~olume rate oE 260 litres per hectare. The treatments were applied as described in F.xperiment 1 Un~:prayed pots were maintained as controls.
- ~6 ~
Ten days after spraying, a visual assess~ent was made of the percentage reduction in top growth of each weed species for ~ach replicate treatmen~ in comparison with untreated control plants. The mean percentage control of each species at each rate o~
application and the mean percentage overall control of all tested weed species was calculated. The results obtained are presented in Table 4 below.
Visual assessment of injury to ~he maize and sorghum plants was also made 10 days after spraying and tbe percentage necrosis o~ the Pntire plan~ was recorded. These results are gi~en in Table 5 below.
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The application rate for each of ~ormulat;ons H to R
~equired to give 95% overall control of all weed species tested was calculated as described in Experiment 1. These application rates giving 95% overall weed control are shown in Table 6 below and clearly demonstrate that bromoxynil trimethylamine and triethylamine salts are more ac~ive than bromoxynil triethanolamine, tri-n-propylamine, tri~n-butylamine and methyl-di-n octylamine salts, from 3 1/~ to 4 times more active than bromoxynil potassium salt and from ~ to 3 times more active than bromoxynil a~monium sal~, in control3.ing the gro~h o broad-leafed weeds by post-emergence applicationO Bromoxynil trimethylamine and triethylamine salts are shown to approach more closely the high level of activity shown by bromoxynil octanoate in controlling the growth of broad-lea~ed weeds by post-emergence applicationl than the other bromoxynil salts tested, and in particular bro~oxynil potassium and am~onium salts, bromoxynil trimethylamine and trimethylamine salts being at ~orst only 1.6 times less active than bromoxynil octanoate in controlling the growth of weeds, whereas~ in eontrast~
bromoxynil potassium and ammonium salts are less than 5 1/2 times and less than 4 times~ respectively, as actiYe as bromoxynil octanoa~eO
~2~7~Z
-- 5', The application rates or each oE Formulations H to R which gave no more than 5% of damage (lea~ necrosis) to the crop plants (maize and sorghum) were similar~y calculated from the results given in Table S and are also ~: 5 shown in TabLe 6 below. The selectivity index was calculated from these figure or each formulation in each crop and these indices are also ~iven in Table 6. The selectivity indices clearly demonstrate that bromoxynil ~: trimethylamine and trieth~lamine salts are highly selective in maize and sorghum, in contrast to bromoxynil triethanolamine, tri-n~propylamine, tri-n-butylamine, methyl-di-n-octylamine, ammonium and potassium salts and-bromoxynil octanoate. The selectivity indices indicate : that bromoxynil trimethylamine and triethylamine salts are from 2~5 to 3,3 times more selective than bromoxynil octanoate in the control of broad-leafed weeds by post-emergence application in maize crops and that bromoxynil trimethyiamine and triethylamine sal~s are from 2.8 to 3.1 times more selective than bromoxynil octanoate in the control of broad~leafed weeds by post~emergence application in sorghum crops. These selectivity indices also indicate that bromoxynil triethanolamine, tri-n-propylamine, tri-n-butylamine, methyl-di-n-octylamine, ammonium ard potassium salts show no advantage in selectivity over bromoxynil octanoate in controlling the growth of broad-leafed weeds by post-emergence applicaton in maize and sorghum crops.
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` ~LZ{377~Z
~ 58 -The following ~xample illu6trcltes the preparation of bromoxynil trimethyl- and triethyl-amine salts.
_XA~IPLE 10 Triethylamine (5.50ml~ was added to a stirred solution oE 3,5~dibromo-4-hydroxybenzonitrile (5.54g) in acetone (40ml). After 10 minutes, when ~he exothermic reaction had subsided, the mixture was filtered and the filtrate was evaporated to dryness to lQ give a solid. The solid ~hus obtained was triturated with ethyl acetate and separated by filtration to give bromoxynil triethylamine salt (which may be - . , alternatively named as tri thylam~,onium 2,6-dibromo-4-cyanophenoxide) (5.1g), in the form of a cream i ~ . ' ,. ~j .~. . !
coloured s~lid, m.p.56-58C LElemental analysis:-C,41.20;H,4.8Q;N,7.30%; calculated for C13H1gBr2N20:- C,41.30;H,4.76jN,7.40~/o3.
By proceeding in a similar manner but replacing the triethylamine by trimetnylamine and the ?~ceton2 by etha~ol, there was ob~ained bromoxynil trimethylami~e salt ~which may be alternatively named as ~rimethyl-ammonium 2,6-dibromo-4-cyan~phenoxide) in the form of a cream coloured solid, m.p. 97-99C lElemental analysis:- C~35~3;H~3~4;N~7~6~/o; calculated for 2~ ~1oH12Br2N~O:-C,35.7;H,3.6;N,8.3tO]~
3J5-Dibromo-4-hydroxybenzonitrile (bromoxynil~
may be prepared as described by Auwers and Reis, Ber., 2g (2~, 2355-2360 (1896).
Claims (12)
1. A method for the selective control of broad-leafed weeds in an emerged crop of maize or sorghum which comprises the post-emergence application to the broad-leafed weeds in a crop of maize or sorghum of a herbicidally-effective amount of the trimethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile at a rate of application of the trimethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile which controls the growth of the broad-leafed weeds without causing substantial permanent damage to the crop.
2. A method according to claim 1 wherein the broad-leafed weeds are at least one of Abutilon theophrasti, Amaranthus spp, Ambrosia artemisiifolia, Amsinkia intermedia, Anchusa arvensis, Anthemis cotula, Ascelepias spp., Aethusa cynapium, Atriplex patula, Brassica kaber, Brassica nigra, Capsella bursa-pastoris, Centaurea cyanus, Chenopodium album, Chorispora tenella, Datura stramonium, Descurainea sophia, Fagopyrum tartaricum, Galinsoga parviflora, Helianthus annuus, Ipomea spp., Kochia scoparia, Lapsana communis, Lithospermum arvense, Matricaria recutita, Matricaria inodora, Myosotis arvensis, Papaver rhoeas, Plantago media, Polygonum spp., Portulaca oleracea, Raphanus raphanistrum, Senecio vulgaris, Sida spinosa, Silene alba, Sinapis arvensis, Solanum nigrum, Solanum elaeagnifollum, Sonchus asper, Sonchus oleracea, Thlaspi arvense, Veronica persica or Xanthium spp.
3. A method according to claim l wherein the broad-leafed weeds are at least one of Abutilon theophrasti, Amaranthus retroflexus, Chenopodium album, Ipomea purpurea, Polygonum lapathifolium, Solanum nigrum or Xanthium strumarium.
4. A method according to claim 1 to 3 wherein the rate of application of the trimethyl-amine salt of 3,5-dibromo-4-hydroxybenzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxy-benzonitrile is such as to apply from 100 to 1000g per hectare of bromoxynil.
5. A method according to claim 1, 2 or 3 wherein the rate of application of the trimethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxy-benzonitrile is such as to apply from 150 to 600g per hectare of bromoxynil.
6. A method according to claim 1 wherein the trimethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile is applied in conjunction with at least one other herbicide which controls the growth of monocotyledonous weeds and/or which is herbicidally active by residual or pre-emergence application and/or which possesses persistent herbicidal ativity and which is well tolerated by maize or sorghum.
7. A method according to claim 6 in which the other herbicide is atrazine, simazine, cyanazine, propazine, terbuthylazine, linuron, isoproturon, dinoseb acetate dinoseb amine, dinoterb, dicamba and salts thereof with metals or amines, 2,4-D and salts thereof with metals or amines and esters thereof, or MCPA and salts thereof with metals or amines and esters thereof.
8. A method according to claim 1 wherein the post-emergence application to the broad-leafed weeds in maize or sorghum crops of the trimethylamine salt of 3,5-dibrono-4-hydroxy-benzonitrile or the triethylamine salt of 3,5-dibromo-4-hydroxy-benzonitrile follows the pre-emergence or pre-planting application, to the area planted with or to be planted with the maize or sorghum crop, of alachlor, metolachlor, pendimethalin, butylate, vernolate, EPTC or a 12:1 mixture of EPTC and N,N-diallyl-2,2-dichloroacetamide.
9. A method according to claim 1 wherein the triethylamine salt of 3,5-dibromo-4-hydroxy-benzonitrile is used.
10. The triethylamine salt of 3,5-dibromo-4-hydroxybenzonitrile.
11. A process for the preparation of the triethylamine salt of 3,5-dibromo-4-hydroxy-benzonitrile which comprises reacting stoichiometric amounts of 3,5-dibromo-4-hydroxybenzonitrile and triethylamine in a suitable inert solvent.
12. A process according to claim 11 wherein the inert solvent is water, a glycol, tetrahydro-furfuryl alcohol, acetophenone, cyclohexanone, isophorone, toluene, xylene or a mineral, animal or vegetable oil.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8228343 | 1982-10-05 | ||
| GB8228343 | 1982-10-05 | ||
| GB8232767 | 1982-11-17 | ||
| GB8232767 | 1982-11-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1207792A true CA1207792A (en) | 1986-07-15 |
Family
ID=26284028
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000438209A Expired CA1207792A (en) | 1982-10-05 | 1983-10-03 | Herbicidal use of trimethylamine and triethylamine salts of 3,5-dibromo-4-hydroxybenzonitrile |
Country Status (7)
| Country | Link |
|---|---|
| AU (1) | AU1986083A (en) |
| BR (1) | BR8305485A (en) |
| CA (1) | CA1207792A (en) |
| ES (1) | ES526214A0 (en) |
| FR (1) | FR2533804A1 (en) |
| IT (1) | IT1171712B (en) |
| RO (1) | RO87551B (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE636416A (en) * | 1962-08-30 | |||
| NL298303A (en) * | 1962-09-24 |
-
1983
- 1983-10-03 CA CA000438209A patent/CA1207792A/en not_active Expired
- 1983-10-03 RO RO112251A patent/RO87551B/en unknown
- 1983-10-04 ES ES526214A patent/ES526214A0/en active Granted
- 1983-10-04 IT IT23131/83A patent/IT1171712B/en active
- 1983-10-04 BR BR8305485A patent/BR8305485A/en unknown
- 1983-10-04 AU AU19860/83A patent/AU1986083A/en not_active Abandoned
- 1983-10-05 FR FR8316052A patent/FR2533804A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ES8600223A1 (en) | 1985-10-01 |
| FR2533804A1 (en) | 1984-04-06 |
| AU1986083A (en) | 1984-04-12 |
| IT8323131A0 (en) | 1983-10-04 |
| RO87551A (en) | 1985-08-31 |
| IT1171712B (en) | 1987-06-10 |
| ES526214A0 (en) | 1985-10-01 |
| BR8305485A (en) | 1984-05-15 |
| RO87551B (en) | 1985-08-31 |
| IT8323131A1 (en) | 1985-04-04 |
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