GB1586463A

GB1586463A - Herbicidal compositions

Info

Publication number: GB1586463A
Application number: GB32087/76A
Authority: GB
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1976-08-02
Filing date: 1976-08-02
Publication date: 1981-03-18
Also published as: AU511681B2; IT1085429B; AU2751277A; FI772334A; DE2734684A1; BE857377A; SU730270A3; PT66870B; SE7708783L; BR7705038A; PL200001A1; ZA774630B; RO72715A; FR2360251A1; CS196217B2; NZ184792A; GR64046B; PT66870A; NO772714L; DK344177A

Description

(54) HERBICIDAL COMPOSITIONS (71) We, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V., a company organized under the laws of the Netherlands, of 30, Careli van Bylandtlaan, The Hague, the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to herbicidally-active compositions comprising a phenoxy-alkanoic acid or derivative thereof and an alanine derivative.

For many years the broad-leaved weeds which infest cereal crops have been successfully controlled by foliar application of plant growth regulator herbicides, such as phenoxy-alkanoic acids and derivatives thereof, known as hormone weed killers.

British patent specifications Nos. 1,164,160 and 1,289,283 disclose that certain alanine derivatives have a herbicidal action upon wild oats and furthermore, that these compounds may be used selectively in cereal crops to control wild oats growing alongside the cereal crops.

It would be most desirable to eradicate both broad-leaved and grass weeds by a single post-emergence application to a cereal crop but it has been observed that the presence of a hormone weed killer has an antagonistic effect on the activity of the alanine derivative grass weed herbicide so that the latter's effectiveness is greatly reduced leading to much poorer control of the grass weeds than is normally achieved by applying the two types of herbicides separately.

It has now surprisingly been found that applying a specific optical isomer of a phenoxy-alkanoic acid or derivative thereof in combination with an alanine derivative gives a virtually unaffected activity with respect to grass weeds whilst maintaining the activity against broad-leaved weeds.

The present invention therefore provides a herbicidal composition comprising as active ingredients at least one R- (' + ) -isomer of a compound of the general formula - * indicating the asymmetric carbon atom -

wherein the or each R independently represents an alkyl group of up to 4 carbon atoms; n is 0 or an integer up to 4; m is 0 or an integer up to 5; R1 represents a hydrogen atom, one equivalent of a metal ion, an optionally alkyl-substituted ammonium ion, or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; and R2 represents an alkyl group of up to 4 carbon atoms; and at least one N,N-disubstituted alanine compound of the general formula:

wherein X represents a fluorine or chlorine atom; Y represents a hydrogen, fluorine or chlorine atom; Q represents an oxygen or sulphur atom; and R3 represents either (i) a group of formula -OR4, wherein R4 represents a hydrogen atom, one equi valent of a metal ion, an optionally alkyl-substituted ammonium ion, or an optionally substituted alkyl, cycloalkyl, alkyl, aryl or aralkyl group; or (ii) a group of formula --SR5, in which R5 represents an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or (iii) a group of formal'a --NR6R' or --ON=CR6R7, in which R8 and R7 each independently represents a hydrogen atom, a hydroxy group, or an optionally substituted alkyl, alkenyl, aryl, aralkyl, heterocyclic, alkoxy, alkylthio or amino group, or R6 and R7 together represent a polymethylene group optionally interrupted by one or more hetero atoms.

The optional substituents referred to in the alanine derivative of formula II are preferably one or two chlorine or fluorine atoms, or alkyl or alkoxy groups containing up to 4 carbon atoms. The alkyl, alkenyl, alkoxy, and alkylthio groups referred to in formula II suitably contain up to 6 carbon atoms, preferably up to 4 carbon atoms.

The aryl, aralkyl, cyclbalkyl, heterocyclic and polymethylene groups suitably contain up to 10 carbon atoms, preferably up to 7 carbon atoms. The hetero-atoms which may interrupt the polymethylene group or be present in the heterocyclic groups may be oxygen, nitrogen or sulphur atoms, and are preferably one or two oxygen and/or nitrogen atoms.

Preferred compositions according to the present invention comprise R- ( + ) -isomers of formula I, wherein n is 0 or 1; m is 1, 2 or 3; R represents a methyl group; R1 represents a hydrogen atom, a sodium or potassium ion, an optionally alkyl-substituted ammonium ion wherein the alkyl group or groups each contain up to 18 carbon atoms, or an alkyl group of up to 18 carbon atoms; and R2 represents a methyl group.

More preferred compounds according to formula I to be used in the compositions according to the invention are potassium and dimethylamine salts of R- ( + )-(4-chloro-2-methylphenoxy)propionic acid, R-( + )-(2,4-dichlorophenoxy)propionic acid; and R- (t + ) - (2,4,5-trichlorophenoxy) propionic acid.

Examples of R- ( + )-phenoxy-alkanoic acids and their derivatives, and their method of synthesis, can be found in our co-pending application No. 32,086/76.

(Serial No. 1 586462) Examples of N,N-disubstituted alanine compounds of formula II and their method of synthesis can be found, for instance, in the following German patent specifications OLS 1 643 527; OLS 2 109 910; OLS 2 302 029; OLS 2 349 970; OLS 2 504 319 and OLS 2 460 691.

Especially preferred N,N-disubstituted alanine compounds of the general formula II are those wherein X and Y each independently represents a fluorine or chlorine atom; Q represents an oxygen atom; and R3 represents a group of formula -OR4, wherein R4 represents a hydrogen atom or an alkyl group of up to 6 carbon atoms, e.g. a methyl, ethyl or isopropyl group. When used in barley crops, preference is given to the use of compounds wherein X represents a fluorine atom; Y represents a chlorine atom; and R3 represents the group -OR4, wherein R4 represents an isopropyl group.

For use in wheat preference is given to those compounds wherein X represents a fluorine or chlorine atom; Y represents a chlorine atom; and R3 represents a group -OR4, wherein R4 represents a methyl or ethyl group.

The N,N-disubstituted alanine compounds of formula I, exist in optically active forms, and generally speaking, the laevo-rotatory isomer with the R-configuration is the more active form. Thus, where it is appropriate, the N,N-disubstituted alanine compounds may be employed in their more active optically-active forms in the compositions according to the present invention.

Good results have been obtained with the ethyl esters of R-(i+ )-(2,4-dichlorophenoxy)propionic acid or R-(i + )-(4-chloro-2-methylphenoxy)propionic acid, together with N-benzoyl-N- (3-chloro-4-fluorophenyl)alanine methyl ester (racemic mixture); N-benzoyl-N- ( 3-chloro-4-fiuorophenyl ) alanine isopropyl ester (racemic mixture); N-benzoyl-N- (3 -chloro-4-fluorophenyl ) alanine isopropyl ester (laevo-rotatory isomer); or N-benzoyl-N- ( 3-chloro-4-fluorophenyl ) alanine ethyl ester (laevo-rotatory isomer).

Wild oat may be controlled in cereal crops by application of from 0.1 to 4 kg/ha of active ingredients in the compositions according to the present invention. The weight ratio of the alanine derivative of formula II to the R-(i + ) -isomer of formula I is preferably in the range from 1:0.2 to 1:25, preferably 1:0.5 to 1:15.

The invention also includes a method of eradicating or controlling both broadleaved and grass weeds infesting cereal crops at a locus by applying to the locus a herbicidally effective amount of an R-( + )-isomer of a compound of formula I and an N,N-disubstituted alanine compound of formula II. Throughout this Specification and claims, " cereal crops" should of course be understood to be crops other than oats.

The herbicidal composition according to the invention may be formulated in such a way as to facilitate its application to the area to be tested and, conveniently, the composition includes a carrier or a surface active agent and usually a carrier and a surface active agent.

The term " carrier" as used herein means a material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound or compounds is mixed or formulated to facilitate its application to the locus to be treated, or its storage, transport or handling. The carrier may be a solid or a fluid. Any of the material usually applied in formulating pesticides may be used as a carrier.

Examples of suitable solid carrier are silicates, clays, for example, kaolinite clay, synthetic hydrated silicon oxides, synthetic calcium silicates, elements such as, for example, carbon and sulphur, natural and synthetic resins, such as, for example, coumarone resins, rosin, copal, shellac, dammar, polyvinyl chloride and styrene polymers and copolymers, solid polychlorophenols, bitumen, asphaltite, waxes, such as for example, beeswax, paraffin wax, montan wax and chlorinated mineral waxes, and solid fertilizers, for example superphosphates.

Examples of suitable fluid carriers are water, alcohols, such as for example, isopropanol, ketones, such as for example, acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethers, aromatic hydrocarbons, such as for example, benzene and toluene, petroleum fractions, such as for example, kerosine, chlorinated hydrocarbons, such as for example, carbon tetrachloride, including liquefied normally vaporous gaseous compounds. Mixtures of different liquids are often suitable.

The surface-active agent may be a wetting agent, an emulsifying agent or a dispersing agent; it may be non-ionic or ionic. Any of the surface-active agents usually applied in formulating herbicides may be used. Examples of suitable surface-active agents are the sodium or calcium salts of polyacrylic acids, the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; partial esters of the above fatty acids with glycerol, sorbitan, sucrose or pentaerythritol; condensation products of alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; and alkali metal salts, preferably sodium salts, of sulphuric acid esters or sulphinic acids containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium alkylaryl sulphonates, such as sodium dodecylbenzene sulphonate.

The compositions of the invention may be formulated as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions and pastes. Wettable powders are usually compounded to contain 25, 50 or 75% of toxicant and usually contain, in addition to solid carrier, 310% of a dispersing agent and, where necessary, 010% of stabilizer(s) and/or other additives, such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant, and are diluted in the field with further solid carrier to give a composition usually containing 0.510% of toxicant. Granules are usually prepared to have a size between 0.15 and 1.68 mm and may be manufactured by agglomeration or impregantion techniques. Generally, granules will contain 0.525% toxicant and 025% of additives, such as stabilizers, slow-release modifiers, binding agents, etc. Emulsifiable concentrates usually contain, in addition to the solvent and, when necessary, co-solvent, 1O50% w/v toxicant, 220% w/v emulsifiers and W20% of appropriate additives, such as stabilizers, penetrants and corrosion inhi bitors. Pastes are compounded so as to obtain a stable, flowable product and usually contain 1060% toxicant, 220% of appropriate additives, and, as carrier, water or an organic liquid in which the toxicant is substantially insoluble.

The compositions of the invention may contain other ingredients, for example, protective colloids, such as gelatin, glue, casein, gums and polyvinyl alcohol; sodium polyphosphates; cellulose ethers, stabilizers, such as ethylene diamine tetra-acetic acid; other herbicides or pesticides; and stickers, for example, non-volatile oils.

Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or an emulsifiable concentrate according to the invention with water, also lie within the scope of the present invention. The said emulsions may be of the water-in-oil or of the oil-in-water type, and may have a thick "mayonnaise"-like consistency.

The notation to indicate the absolute configuration of the phenoxy-alkanoic acids and acid derivatives is as stated in Experientia, Volume 12, pages 81-94, 1956.

The invention is further illustrated by reference to the folowing Examples: EXAMPLE 1.

Demonstration of the effect of phenoxy-propionic acid derivatives on the activity of N-benzoyl-N- (3 chloro-4-fiuorophenyl) -alanine methyl ester The following phenoxy propionate derivatives were formulated as 20% emulsifiable concentrates: 2,4-dichlorophenoxy propionic acid ethyl ester (racemic mixture) (A) R-(! + )42,4-dichlorophenoxy)propionic acid ethyl ester (B) (4 chloro-2-methylphenoxy)propionic acid ethyl ester (racemic mixture) (C) R-(l+ )-(4-chloro-2-methylphenoxy)propionic acid ethyl ester (D) The compounds were applied as "in-tank mixtures" with a 15% emulsifiable concentrate of N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine methyl ester (racemic mixture) (E) to cultivated oat at the 1 11 leaf stage. The dosages used for compound (E) were 0.05, 0.1 or 0.2 kg/ha in all treatments. Sufficient amounts of the compounds A, B, C and D were added to produce mixtures with the ratios as indicated in the Table. The compound E was also applied alone.

After spraying (single dose sprays in a total volume of 650 I/ha) the plants were set out in randomized blocks in the glasshouse (there were 4 replicates of each treatment). Phytotoxicity was assessed visually on a W100 scale (where 0=no effect and 100=no visible growth after spraying) 7 and 13 days after spraying and by fresh shoot weight 20 days after spraying. The amounts of R- ( + )-phenoxyalkanoic acid derivatives used in the compositions according to the invention are lower than the amounts of the corresponding racemates in the compositions tested for comparative purposes so as to account for the higher activity of the R-(j + )-phenoxy alkanoic acid derivatives in the compositions according to the invention. The mean results obtained using 0.2 kg/ha of compound (E) are shown in Table I, the fresh weights being expressed as % reduction in total weight of untreated control.

TABLE I

7 days 13 days fresh 20 days 1st % 2nd % weights % Weight visible reduction visible reduction % reduction Compound(s) ratio score in activity score in activity reduction in activity E - 99 - 97 - 86 E+A 1:4 91 8 40 59 23 73 1:8 71 20 30 69 26 70 E+B 1:2 98 1 88 9 68 21 1:4 89 10 53 45 33 62 E+C 1:4 95 4 78 20 50 33 1:8 84 15 39 60 36 58 E+D 1:2 98 1 90 7 76 12 1:4 94 5 76 22 55 36 The results given in Table I clearly indicate that using the R-(+)-isomer of the phenoxy-propionic acid derivatives (B, D) causes a significantly smaller reduction in activity of the N,N-disubstituted alanine compound which makes it possible to use such a mixture in a single operation to eradicate or to control both broad-leaved and grass weeds.

EXAMPLE 2.

Demonstration of the effect of phenoxy propionic acid derivatives on the activity of Nbenzoyl-N-(3-chloro-4-fluorophenyl)alanine isopropyl ester The compounds A, B, C and D as described in Example 1 were applied (20% emulsifiable concentrates) as " in-tank " mixtures with 20% emulsifiable concentrates of N - benzoyl - N - (3 - chloro - 4 - fluorophenyl)alanine isopropyl ester (racemic mixture (F) and R - (-) - N - benzoyl - N - (3 - chloro - 4 - fluorophenyl)alanine isopropyl ester (laevo-rotatory isomer) (G) to cultivated oat at the 11+ leaf stage.

The dosages used for compound (F) were 0.1, 0.2 or 0.4 kg/ha and for compound (G) 0.05, 0.1 or 0.2 kg/ha in all treatments. The compounds (F) and (G) were also applied alone.

The spraying was carried out as described in Example 1. Phytotoxicity on a 0- 100 (visible) scale was assessed 7 and 14 days after spraying and by fresh shoot weight 15 days after spraying. The mean results obtained using 0.4 kg/ha of compound (F) and 0.2 kg/ha of compound (G) are given in Table II.

Again the results obtained indicate that using R-(f+ )-phenoxy propionic acid derivatives (B, D) causes a significantly smaller reduction in activity for the N,Ndisubstituted alanine compounds. In combination with R-( - )-N-benzoyl-N-(3-chloro4-fluorophenyl) alanine isopropyl ester, virtually no reduction of activity has been found at all.

EXAMPLE 3.

Demonstration of the effect of phenoxy-propionic acid derivatives on the activity of R- ( - ) -N-benzoyl-N- (3 -chloro-4-fiuorophenyl) alanine ethyl ester The compounds A, B, C and D (20% emulsifiable concentrates) as described in the previous Examples were applied as "in-tank" mixtures with 20% emulsifiable concentrate of R-( - )-N-benzoyl-N-(3-chloro-4;fluorophenyl')alanine ethyl ester (H) to cultivated oat at the 1--1- leaf stage. The compound (H) was also applied alone.

The spraying was carried out as described in Example 1. Phytotoxicity on a 0- 100 (visible) scale was assessed 7 and 14 days after spraying and by fresh shoot weight 15 days after spraying. The mean results obtained using 0.2 kg/ha of compound (H) are given in Table III.

Again the results obtained clearly indicate the significantly reduced antagonistic effect of R-(l+ )-phenoxy propionic acid derivatives on the activity of N,N-disubstituted alanine derivatives.

TABLE II

7 days 14 days fresh 15 days 1st % 2nd % weights % Weight visible reduction visible reduction % reduction Compound(s) ratio score in activity score in activity reduction in activity F - 77 - 52 - 30 F+A 1:2 50 35 23 56 22 27 1:4 53 31 37 29 24 20 F+B 1:1 80 0 47 10 29 3 1:2 60 22 50 4 33 0 F+C 1:2 53 31 48 8 27 10 1:4 55 39 60 0 36 0 F+D 1:1 82 0 62 0 38 0 1:2 72 6 55 0 38 0 G - 85 - 67 - 44 G+A 1:4 67 21 58 13 32 27 1:8 48 44 57 15 31 30 TABLE II (Continued)

7 days 14 days fresh 15 days 1st % 2nd % weights % Weight visible reduction visible reduction % reduction Compound(s) ratio score in activity score in activity reduction in activity G+B 1:2 85 0 65 3 35 20 1:4 75 12 57 15 35 20 G+C 1:4 87 0 77 0 41 7 1:8 67 21 63 6 33 25 G+D 1:2 86 0 78 0 46 0 1:4 82 4 67 0 42 5 TABLE III

7 days 14 days fresh 15 days 1st % 2nd % weights % Weight visible reduction visible reduction % reduction Compound(s) ratio score in activity score in activity reduction in activity H - 97 - 88 - 70 H+A 1:4 94 3 68 23 46 34 1:8 80 18 72 18 36 49 H+B 1:2 96 1 87 1 67 4 1:4 92 5 78 11 54 23 H+C 1:4 98 0 92 0 69 1 1:8 92 5 82 7 47 33 H+D 1:2 98 0 87 1 74 0 1:4 98 0 87 1 71 0

Claims

WHAT WE CLAIM IS:1. A herbicidal composition comprising as active ingredients at least one R-(+)isomer of a compound of the general formula - * indicating the asymmetric carbon atom -

wherein the or each R independently represents an alkyl group of up to 4 carbon atoms; n is 0 or an integer up to 4; m is 0 or an integer up to 5; R' represents a hydrogen atom, one equivalent of a metal ion, an optionally alkyl-substituted ammonium ion, or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; and R2 represents an alkyl group of up to 4 carbon atoms; and at least one N,N-disubstituted alanine compound of the general formula:

wherein X represents a fluorine or chlorine atom; Y represents a hydrogen, fluorine or chlorine atom; Q represents an oxygen or sulphur atom; and R represents either (i) a group of formula -OR4, wherein R4 represents a hydrogen atom, one equi valent of a metal ion, an optionally alkyl-substituted ammonium ion, or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or (ii) a group of formula -SR5, in which R5 represents an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or (iii) a group of formula -NR6R7 or -ON CR6R7, in which R6 and R7 each independently represents a hydrogen atom, a hydroxy group, or an optionally substituted alkyl, alkenyl, aryl, aralkyl, heterocyclic, alkoxy, alkylthio or amino group, or R6 and R7 together represent a polymethylene group optionally interrupted by one or more hetero atoms.
2. A herbicidal composition according to claim 1, wherein n is 0 or 1; m is 1, 2 or 3; R represents a methyl group; R1 represents a hydrogen atom, a sodium or potassium ion, an optionally alkyl-substituted ammonium ion wherein the alkyl group or groups each contain up to 18 carbon atoms, or an alkyl group of up to 18 carbon atoms; and R2 represents a methyl group.
3. A herbicidal composition according to claim 2, wherein the potassium or dimethylamine salts of R-(l+ )-(4-chloro-2-methylphenoxy)-propionic acid, R-( + )- (2,4-dichlorophenoxy) -propionic acid or R- ( + ) - ( 2,4,5-trichiorophenoxy) -propionic acid are used as active ingredient.
4. A herbicidal composition according to any one of the preceding claims, wherein X and Y each independently represents a fluorine or chlorine atom; Q represents an oxygen atom; and R3 represents a group of formula -OR4, wherein R4 represents a hydrogen atom or an alkyl group of up to 6 carbon atoms.
5. A herbicidal composition according to claim 4, wherein X represents a ,fluorine atom; Y represents a chlorine atom; and R3 represents a group -OR4, wherein R4 represents an isopropyl group.
6. A herbicidal composition according to claim 4, wherein X represents a fluorine or chlorine atom; Y represents a chlorine atom; and R3 represents a group -OR4, wherein R4 represents a methyl or ethyl group.
7. A herbicidal composition according to any one of the preceding claims, wherein a laevo-rotary isomer of a compound according to formula II is used as active ingredient.
8. A herbicidal composition according to claim 7, wherein the ethyl ester of either R-( + )-(2,4-dichlorophenoxy)-propionic acid or R-( + )-(4-chloro-2-methylphenoxy)-propionic acid is used as active ingredient together with the laevo rotatory isomer of either N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine isopropyl ester or N-benzoyl N-( 3-chloro-4-fluorophenyl )alanine ethyl ester.
9. A herbicidal composition according to any one of the preceding claims, wherein the weight ratio of the alanine derivative of formula II to the R-( + )-isomer of formula I is in the range from 1:0.2 to 1:25.
10. A herbicidal composition according to any one of the preceding claims, comprising also a carrier, a surface-active agent or both a carrier and a surface-active agent.
11. A herbicidal composition according to any one of the preceding claims, wherein the amount of active ingredients is 0.5-75 %w.
12. A herbicidal composition according to claim 1, substantially as described in any one of the Examples herein.
13. A method of eradicating or controlling broad-leaved and grass weeds in cereal crops at a locus which comprises applying to the locus a herbicidally active amount of an R-( + )-isomer of a compound of formula I as defined in claim 1 and an N,Ndisubstituted alanine derivative of formula II as defined in claim 1.
14. A method according to claim 13, which comprises applying an R- (..+ ) -isomer of a compound of formula I and a laevo-rotatory isomer of an N,N-disubstituted alanine derivative of formula II.
15. A method according to claim 13, substantially as described in any one of the Examples herein.