GB2144125A - Derivatives of aryloxybenzoic acids and their use as herbicides - Google Patents

Abstract

A herbicide which has the formula: <IMAGE> in which: X denotes a halogen atom or a lower alkyl radical optionally substituted by one or more halogen atoms, Y denotes a hydrogen or halogen atom, or a CF3, CN, NO2 or CH3 radical, D denotes the nitrogen atom or the radical -C(Z) in which Z denotes a hydrogen or halogen atom, W denotes a hydrogen or halogen atom or the nitro radical, R denotes the hydrogen atom, or a halogen atom, or an aliphatic or aromatic, alkylthio, amino, carboxy or derivatives, alkylsulphonyl, arylsulphonyl, hydroxy or cyano radical, optionally substituted, if appropriate, with one or more atoms or radicals selected from halogen, alkoxy, alkoxyalkoxy, hydroxy, lower alkyl, acyl, carboxyl and salts or esters of this carboxyl group, and its agriculturally acceptable salts.

Description

SPECIFICATION New derivatives of aryloxybenzoic acids and their use as herbicides The invention relates to new herbicidal compounds containing a tetrazole group, derived from aryloxybenzoic acids. It also relates to the preparation of these new compounds and to the compositions for use in agriculture in which they are present.

2-N itrn-5-12'-chlorn-41-(trifluoromethyl)phenoxy] benzoic acid, also called acifluorfen, and its salts, are known, as is their use as herbicides particularly for the weeding of soya.

Furthermore, numerous derivatives of acifluorfen have already been proposed, in particular alkyl, cycloalkyl, thioalkyl or phenyl esters, as well as mono- or dialkylated amides. Such compounds are described in U.S. Patents 3,652,645, 3,784,635, 3,873,302, 3,983,168, 3,907,866, 3,798,276, 3,928,416, and 4,063,929.

The present invention relates to derivatives of aryloxybenzoic acids, which differ from those described in the prior art and have an outstanding herbicidal activity.

The new products according to the invention are compounds of the general formula (I):

in which: X denotes a halogen atom, or a lower alkyl radical optionally substituted by one or more halogen atoms, Y denotes a hydrogen or halogen atom, or a CF3, CN, NO2 or CH3 radical, D denotes the nitrogen atom or the radical -C(Z) = in which Z denotes a hydrogen or halogen atom, W denotes a hydrogen or halogen atom or the nitro radical, R denotes the hydrogen atom or a halogen atom, or a radical chosen from aliphatic or aromatic or alkylthio or amino or acyl (derived from e.g. an organic carboxylic acid and including alkanoyl, carboxy, esterified carboxy and carbamoyl optionally substituted by e.g. one or two lower alkyl groups), or alkylsulphonyl or arylsulphonyl or hydroxy or cyano radicals, these various radicals may be substituted if appropriate; possible substitutents which may be mentioned are the following atoms or radicals: halogen, alkoxy, alkoxyalkoxy, hydroxy, lower acyl, carboxyl, salts and esters (carboxylates) of this carboxyl group such as, e.g., lower alkoxycarbonyls; More particularly R can have one or other of the following meanings:: -optionally substituted alkyl, e.g. lower alkyl unsubstituted or substituted with one or more of the abovementioned atoms or radicals; -optionally substituted aryl, with, e.g., substituents similar to those mentioned above; -lower alkenyl; -lower alkynyl; -lower alkylthio which may be substituted, e.g., with one or more halogen atoms; amino, which may be substituted, e.g., with one or more lower alkyl radicals or with an acyl radical; VO-R' in which R' denotes a substituent, e.g. the OH radical or a lower alkoxy radical or an aryloxy radical, or the amino radical itself which may be substituted;; -SO2-R" in which R" denotes a substituent, such as, for example, an alkyl or aryl radical; -or an -OH or -CN radical.

Within the meaning of the present text, the adjective "lower", when applied to a radical, means that this radical contains at most 6 carbon atoms.

The broken lines in the formula (I) show the existence of a tautomerism.

The compounds of the formula (I) in which R denotes the hydrogen atom are acidic in nature and consequently can form, with suitable bases, agriculturally acceptable salts. These salts may also be employed as herbicides and are therefore also included in the scope of the invention. As examples of such salts, there may be mentioned salts of metals, preferably of alkali metals such as sodium, potassium or lithium, or alkaline-earth metals such as calcium or magnesium, or ammonium salts or salts containing ammonium which is mono- or polysubstituted such as isopropylammonium, triethanolammonium, morpholinium, and the like.

Depending on the position of the substituent R on the tetrazole ring, the compounds of the formula (I) can exist in two isomeric forms (IA) and (IS) which are also included in the scope of the invention, and in which the various substituents have the same meaning as in the formula (I)

Among the compounds of the formula (I), (IA) and (IB), a subfamily which is preferred on account of its remarkable herbicidal properties is formed by the compounds in which: X denotes the trifluoromethyl radical Y denotes the chlorine atom D denotes the -CH = radical W denotes the nitro group or the hydrogen atom, and R denotes an alkyl radical which may be substituted (for example with a lower alkoxycarbonyl radical).

The invention also relates to the preparation of the compounds of the formula (I) and agriculturally usable salts of these compounds.

The compounds of the formula (I) may be prepared by a reaction of a phenyltetrazole of the formula (II)

in which W and R have the same meaning as in formula (I) and A denotes the hydroxy radical or a halogen atom (preferably fluorine or chlorine), with the compound of the formula (III)

in which X, Y and D have the same meaning as in the formula (I) and B denotes a halogen atom (preferably fluorine or chlorine) or the hydroxy radical, it being understood that B is chosen different from A, i.e. B denotes a halogen atom when A denotes the hydroxy radical and B denotes the hydroxy radical when A denotes the halogen atom.

When it is desired to prepare a compound of the formula (I) in which W denotes the hydrogen atom, the other substituents or symbols having the same meaning as in the formula (I), a phenyltetrazole (II) in which A denotes the hydroxy radical, and a compound (III) in which B denotes the halogen atom, are preferably chosen as starting materials.

When it is desired to prepare a compound of the formula (I) in which W denotes the nitro radical, the other substituents or symbols having the same meaning as in the formula (I), a phenyltetrazole (II) in which A denotes the halogen atom, and a compound (III) in which B denotes the hydoxy radical, are preferably chosen as starting materials.

The reaction between the phenyltetrazole (II) and the compound (III) is generally carried out in the presence of a basic agent, at a temperature of between 80 and 180"C approximately, in a polar aprotic solvent, such as, e.g., dimethyl sulphoxide, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, acetonitrile, acetone or in other equivalent polar aprotic solvents.

Sodium or potassium hydroxides or carbonates are advantageously employed as a basic agent. It is also possible to use the compounds of the formula (Il) or (III) with a hydroxy group, in the form of an alkali phenate or pyrid-2-ylate, formed beforehand.

The phenyltetrazole of the formula (II), which is employed as starting material, may be prepared by a reaction of NaN3 with a nitrile of the formula (V)

in which A and W have the same meaning as in the formula (II), provided that when W denotes the nitro radical, A must denote a halogen atom. This reaction is carried out according to the method described by K. Kadaba in Synthesis-1 973-p. 71-84.

This produces the phenyltetrazole of the formula (II) in which A and W have the same meaning as above and R denotes the hydrogen atom.

The phenyltetrazoles of the formula (II) in which R denotes a substituent other than the hydrogen atom may be prepared from the phenyltetrazole obtained earlier, by reaction with a reactant of the formula (VIII) R-T (VIII) in which R has the same meaning as earlier and T denotes a reactive leaving group such as, e.g., a halogen atom (preferably the iodine or bromine atom) or an arylsulphonic radical such as the benzenesulphonyloxy, toluenesulphonyloxy, or xylenesulphonyloxy radicals.

The compounds of the formula (I) in which W denotes a halogen atom or the nitro radical, the other substituents or symbols having the same meaning as in the formula (I), can also be obtained respectively by halogenation or nitration of the compound of the formula (I) in which W denotes the hydrogen atom and which has the formula (IV) below:

in which X, Y, D and R have the same meaning as in the formula (I).

Nitration of the compound (IV) may be carried out with the use of a conventional nitrating agent, such as nitric acid, or potassium nitrate in the presence of sulphuric acid, if appropriate in an inert organic solvent, advantageously a chlorinated hydrocarbon, such as methylene chloride, perchloroethylene, chloroform, and the like, usually by carrying out the reaction at a low temperature (between - 20"C and + 20"C).

Halogenation of the compound (IV) may be carried out, e.g., by reaction with a halogen, in a solvent such as acetic acid, and with heating (e.g. by boiling under reflux).

The compounds of the formula (I) in which W and R denote the hydrogen atom, the other substituents and symbols having the same meaning as in the formula (I), can also be prepared by the reaction of NaN3 with a nitrile of the formula (VI):

in which X, Y and D have the same meaning as in the formula (I), by the method of K. Kadaba described above. This produces the compounds of the formula (VII):

in which the various symbols and substituents have the same meaning as before.

The compounds of the formula (I), in which R denotes a substituent other than the hydrogen atom, may also be prepared from compounds of the formula (VIIA) hereinafter depicted the preparation of which is described above, by reacting this compound with a reactant of the formula (VIII) R-T (VIII) in which R and T have the abovementioned meanings.

The reaction is generally carried out in an inert organic solvent medium, at a temperature of the order of 20 to 150"C approximately.

As mentioned earlier, salts of the compounds of the formula (I) in which R denotes the hydrogen atom, may be obtained by treating these compounds with a suitable base, preferably sodium hydroxide.

At the end of the operation, according to one or other of the processes described above, the compound (I), or the salt of this compound, is separated from the reaction mixture by means of usual techniques such as, e.g., distillation of the solvent, or crystallisation of the compound from the reaction medium. If necessary, it is then purified by conventional methods such as recrystallisation from a suitable solvent or liquid phase chromatography or vapour phase chromatography.

The following examples illustrate the invention without, nevertheless, restricting it. The structure of the compounds described in these examples was characterised by infrared spectrometry, by nuclear magnetic resonance spectrometry (NMR) and by elemental analysis.

Example 1: Preparation of 5-C3'-(2"-chloro4'-trif luoromethylphenoxy)phenylltetrazole (compound no. 1) Methanol (0.15 I) is placed in a 1-litre 3-necked round flask, then potassium hydroxide pellets (13.2 g) are added portion-wise, followed by a single addition of 5-(3'-hydroxyphenyl)tetrazole (crystallised with 1 mole of water) (18 g; 0.1 mole), while the temperature is maintained below 30"C. The whole is kept at this temperature for approximately half an hour and the solvent is distilled off under a reduced absolute pressure of approximately 1 millibar. The potassium salt of 5-(3'-hydroxyphenyl)-tetrazole is obtained in this way in the form of a brown oil.

This brown oil is then dissolved in diemethyl sulphoxide (100 ml), 3,4-dichloro(trifluoromethyl) benzene (21.5 g; 0.1 mole) is added to the solution and the reaction mixture is heated for 5 hours at 1 30 C, after which the temperature is allowed to return to room temperature (approximately 25"C). The reaction mixture is then poured into water (500 ml). The aqueous phase is extracted with methylene chloride (2 X 100 ml). The aqueous phase is then collected and acidified to pH 1 with aqueous concentrated HCI. Formation of crystals consisting of unreacted tetrazole is seen, together with an oil which is dissolved in methylene chloride (200 ml). The organic phase obtained is washed several times with water and dried over sodium sulphate. The solvent is then distilled off and the oil thus produced is mixed with water (100 ml).The dark-coloured crystals produced are filtered, washed with water, then dried in an oven and finally recrystallised in a 50/50 mixture of water and ethanol.

Compound No. 1 of the formula:

(13.2 g) is thus obtained.

Yield: 38% m.p.: 173'C.

The 5-(3-hydroxyphenyl)tetrazole employed as starting material was prepared by reaction of NaN3 with 3-cyanophenol, in dimethylformamide in the presence of ammonium chloride by a method similar to that described in Synthesis, 1973, p. 71 to 84.

Compound No. 1 has also been obtained by a second method, described below: 3-(2'-Chloro-4'-trifluoromethylphenoxy)benzonitrile (17.6 9; 0.059 mole), NaN3 (4.2 g; 0.065 mole), ammonium chloride (3.4 g; 0.065 mole) and dimethylformamide (30 ml) are placed in a 3-necked round flask. The reaction mixture is heated for 4 hours at 100"C, is allowed to return to room temperature and is poured into water (500 ml). A solution is obtained to which HCI (6N) is added until the pH is 1 and stirring is continued for 10 min. A white precipitate is formed, which is filtered off and then washed with water. After filtering, and drying in air, compound No. 1 (19.5 g) is obtained.

The 3-(2'-chloro-4'-trifluoromethylphenoxy)benzonitrile was prepared by reaction of trifluoroacetic an hydroxide with 3-(2'-chloro-4'-trifluoromethylphenoxy)benzamide.

Example 2: Preparation of 5-21-nitrn-51-(211-chlorn-411-trifluornmethylphenoxy)phenyltetrazole (compound No. 2).

Compound No. 1(9.2 9; 0.027 mole) is dissolved in concentrated sulphuric acid (40 ml), and 1,2-dichloroethane (40 ml) is added to the solution thus obtained.

While the reaction mixture is maintained is 0 C, and stirred, potassium nitrate (2.7 g; 0.027 mole) is added gradually over 1 5 minutes, and then the mixture is kept for half an hour at this temperature and finally for 1 hour at room temperature.

The reaction mixture thus obtained is poured into a mixture of ice and water (400 g). After extraction with dichloromethane (2 X 100 ml), the organic phase is dried, then the solvent is removed by distillation. An 80/20 mixture of 5-[2'-nitro-5'-(2"-chloro-4"-trifluoromethyiphenox- y)phenyl]tetrazole and 5-[21-nitrn-31-(211-chlorn-411-trifluornmethylphenoxy)phenyljtetrnzole (8 g) (78% yield) is obtained.

Chromatography on silica (eluent: ethanol/CH2Cl2/acetic acid in proportions of 1.5/15/0.1 by volume respectively), gives the required compound (compound No. 2) of the formula:

(4.2 g).

Yield: 47% m.p.: 142"C, together with 5-[2'-nitro-3'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (0.4 9), which melts at 206"C.

Example 3: Preparation of the sodium salt of compound No. 2. This salt is compound No. 3.

Compound No. 2 (1.16 g) is dissolved in water (10 ml) and one equivalent of 1 N sodium hydroxide.

Water is removed by distillation under reduced pressure at 60"C and the required compound (0.9 9) is thus obtained in the form of a yellow solid, of the formula

Yield: 75% m.p. above 250"C.

Example 4: Preparation of 2-methyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)pheny- l]tetrazole (compound No. 4A) and of 1 -methyl-5-(2'-nitro-5'-(2"-chloro-4"-trifluoromethylphe- noxy)phenul]tetrazole (compound No. 4B).

In a 250 ml 3-necked round flask are placed compound No. 2 (7.72 g; 0.02 mole), methyl iodide (14.2 g; 0.1 mole), dimethylformamide (50 ml) and anhydrous potassium carbonate (2.76 g; 0.02 mole) and the reaction mixture is heated for 15 hours at 70"C. The solvent is then removed by distillation under reduced pressure (10 millibars) and the mixture is taken up with water (100 ml) and CH2CI2 (2 X 100 ml). The organic phase is collected and then dried over sodium sulphate. After the solvent has been distilled off under reduced pressure, an oil (8 g) is obtained, which is chromatographed on silica (diisopropyl ether eluent).

Compound No. 4A of the formula:

(5.1 g) is thus obtained.

Yield: 63% m.p.: 90-92"C together with compound No. 4B of the formula:

(0.5 9), melting at 148"C.

Using another preparative method, it has also been possible to obtain compound No. 4A by nitration of 2-methyl-5-[3'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (m.p.: 80'C-yield 72%), the latter compound itself having been obtained by alkylation of compound No. 1.

Example 5: Preparation of 2-methyl-5-[2'-nitro-5'-(2",4"-dichlorophenoxy)phenyl]tetrazole (compound No. 5) 2-Methyl-5-(2'-nitro-5'-fluorophenyl)tetrazole (5.4 9; 0.024 mole), 2,4-dichlorophenol (3.9 g; 0.024 mole), potassium carbonate (3.3 9; 0.024 mole) and dimethylformamide (50 ml) are placed in a 100-ml 3-necked round flask. The reaction mixture is stirred for 30 min. at room temperature, then heated for 7 hours at 80"C. It is allowed to cool and then the solvent is evaporated off under reduced pressure. An oil is obtained which is taken up in CH2CI2 (150 ml), then washed with water (3 x 50 ml); it is separated off. After the organic phase has been dried over Na2SO4, it is filtered and then evaporated and a yellow oil is thus obtained which is crystallised from a mixture of equal voiumes of diisopropyl ether and hexane.After filtering, washing with diisopropyl ether (2 X 1 5 ml), filtering and drying in air, the required compound, of the formula (compound No. 5):

(5.8 9) is obtained.

m.p.: 115"C Yield: 66% The 2-methyl-5-(2 '-nitro-5'-fluorophenyl)tetrazole employed as starting material was prepared by alkylation of (2-nitro-5-fluorophenyl)tetrazole in acetone with Cm31, in the presence of K2CO3. 5 (2-Nitro-S4luorophenyl)-tetrazole was itself prepared by nitration of 5-(3'-fluorophenyl)tetrazole with nitric acid.

Examples 6 to 15: Compounds No. 6 to 1 5 were prepared using the method of Examples 4, from appropriate starting materials.

The different compounds obtained in the various Examples 1 to 15, with the exception of compound No. 4B (a compound has the number of the example which corresponds to it) have the formula:

The meaning of the substituents X, W and R in the various compounds, together with the yield (Y) of the example and the melting point of the product (or its spectral characteristics), are collated in Table (I). The compounds which contain an asymmetric carbon atom exist in the two enantiomeric forms R and S. In this case, the formula (X) [similarly to formula (I)] must be understood to denote either of these two forms, or denote the mixture of both in proportions which are either equivalent (a racemate) or in which either of the forms predominates.

The following compounds may be prepared by a method which is similar to that of Example 4: 2-(1-methoxycarbonylethyl)-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethyl-phenoxy)phenyl]tetra zole (R enantiomer), 2-(1 -methoxycarbonylethyl)-5-[2'-nitro-5 '-(2 "-chloro-4"-trifluoromethyl)phe- noxy]tetrazole (S enantiomer), 2-(1 -methoxycarbonylethyl)-5-[2'-nitro-5 '-(3"-chloro-5 "-trifluoro- I methyl-pyridyl-2"-oxy)phenyl]tetrazole (racemate, together with its R enantiomer and its S enantiomer).

The following examples, No. 16 to 20, illustrate the herbicidal properties of the compounds according to the invention.

Example 1 6-Herbicidal activity in a greenhouse, during pre-emergence of plant species An aqueous suspension having the following composition is prepared: active ingredient to be tested 40 mg -Tween 80 50 mg -:listilled water containing 1 part per 1,000 by weight of Scurol O. . q.s. 40 ml by grinding the active ingredient and then suspending it in water containing Tween 80 and Scurol O.

Tween 80 is a wetting agent consisting of a condensate of ethylene oxide with sorbitan monolaurate.

Scurol O is a surface-active agent consisting of condensates of ethylene oxide with alkylphenols, principally a condensate of ethylene oxide (10 moles) with octylphenol.

The aqueous suspension described above is then, if need be, diluted with distilled water containing 1 part per 1,000 of Scurol O, so as to produce the required concentration.

The pots employed are 6.5 cm in diameter and 8 cm high, filled half with clay loam soil and half with river sand.

30 seeds of one of the following plant species are sown in each pot: Symbols Wheat (Triticum sativum), Caton variety TRIT Slender foxtail (Alopecurus myosuroides) ALO P Wild oat (Avena fatua) AVEN Lentil (Lens culinaris), Large golden variety LENS Radish (Raphanus sativus), Round pink with white end variety RAPH Beetroot (Beta vulgaris), Ceres variety BETA Lettuce (Lactuca sativa), gotte golden yellow variety LACT Buckwheat (Polygonum fagopyrum) FAG Amaranth (Amaranthus caudatus) AMA The pre-emergence treatment is carried out by spraying the aqueous suspension of the active ingredient, at the required concentration, over the seeded surface, each pot receiving approximately 0.3 ml of the aqueous suspension.

After treatment, the seeded surface is left to dry and then the seeds are covered with a layer of soil approximately 2 mm in thickness.

The pots are watered by spraying twice daily and are kept in a greenhouse at a temperature of 22 to 24"C, under a relative moisture of 70 to 80%, under artificial lighting giving approximately 5,000 lux in the region of the plants, during 16 consecutive hours per 24 hours.

21 Days after the treatment, note is taken of the number and height of the living plants in the pots treated with the active ingredient being tested and also the number and height of the same plants in the control pots which have been treated under the same conditions, without the active ingredient.

In this way, a determination is made of: -the percentage of reduction in number N%, calculated as follows: number of living plants in the treated pots NZ = x 100 number of living plants in the control pots -the percentage of reduction in height H%, calculated as follows: mean height of the living plants in the treated pots x s x 100 mean height of the living plants in the control pots From N% and H%, THE PERCENTAGE RELATIVE TO THE CONTROL, equal to: N% x H% 100 is calculated.

The values obtained in this way are shown in Table (II). In this table, a value of 0 denotes a total herbicidal activity and a value of 100 denotes the total absence of herbicidal acitivity.

Example I 7-Herbicidal activity in a greenhouse, during post-emergence of the plant species The method described in Example 1 6 is followed, but with the following differences: -after the seeds have been scattered, they are covered with a layer of soil approximately 5 mm in thickness, the pots are placed in the greenhouse and the seeds are left to germinate so as to produce plantlets at the required stage of development, -the treatment using the compounds according to the invention is carried out when the plants are at the following stage:: -2 to 3 leaf stage for wheat, foxtail, lettuce and amaranth, -3 true leaf stage for lentils, -2 well developed cotyledon leaf stage for buckwheat, beetroot and radish; according to this post-emergence treatment, the solution or suspension containing the active ingredient is sprayed on the plant and the plants are then left to dry.

As in the case of the preceding example, the results are observed 21 days after the treatment and the percentage relative to the control is thus determined according to the method described in the preceding example.

The values obtained in this way are shown in Table (III).

Example 1 8-Herbicidal activity and cultivation selectivity in a greenhouse, during postemergence of the plant species The method described in Example 1 7 is followed using the following plants: Crops Rice (Oryza sativa) Wheat (Triticum vulgare) Adventicious plants Slender foxtail (Alopecurus myosuroides) Panic grass (Echinochloa crus-galli) Green bristlegrass (Setaria viridis) Indian mallow (Abutilon theophrasti) Prickly sida (Sida spinosa) Annual chrysanthemum (Chrysanthemum annuum) Rounded chamomile (Matricaria matricarioides) Common speedwell (Veronica persica) Narrow leaved plantain (Plantago lanceolata) Garden amaranth (Amaranthus caudatus) Black nightshade (Solanum nigrum) White mustard (Sinapis alba) Field bindweed (Convolvulus arvensis) Common chickweed (Stellaria media).

The percentages relative to the control are determined according to the method described in Example 1 7. The values obtained in this way are shown in Table (IV).

Example 19: Herbicidal application during pre-emergence of the plant species A number of seeds which is determined as a function of the plant species and seed size is sown in 9 X 9 X 9 cm pots filled with light agricultural soil.

The pots are treated by spraying with an amount of spray mixture which corresponds to a volume application dose of 500 I/ha and contains the active ingredient at the required concentration.

The treatment with the spraying mixture is thus carried out on seeds which are not covered with soil (the term spraying mixture is employed to denote, in general, water-diluted compositions, such as applied to the plants).

The spraying mixture employed for the treatment is an aqueous suspension of the active ingredient containing 0.1% by weight of Cemulsol NP 10 (surface active agent consisting of a polycondensate of ethylene oxide and an alkylphenol, particularly a polycondensate of ethylene oxide and nonylphenol) and 0.04% by weight of Tween 20 (surface-active agent consisting of an oleate of a polycondensate of ethylene oxide derivative of sorbitol).

This suspension was prepared by mixing and grinding the components in a microniser, so as to produce a mean particle size below 40 microns.

The applied dose of active ingredient was 0.125 to 2 kg/ha, depending on the concentration of active ingredient in the spraying mixture.

After treatment, the seeds are covered with a layer of soil approximately 3 mm thick.

The pots are then placed in troughs intended to receive the moistening water, by subirrigation, and are kept for 21 days at ambient temperature under 70% relative humidity.

After 21 days, the number of living plants in the pots treated with the spraying mixture containing the active ingredient being tested and the number of living plants in a control pot treated under the same conditions, but with a spraying mixture which does not contain active ingredient, are counted. The percentage destruction of the treated plants relative to the untreated control is thus determined. A destruction percentage equal to 100% indicates that complete destruction of the plant species under consideration has taken place and a percentage of 0% indicates that the number of living plants in the treated pot is identical to that in the control pot. The results obtained in this Example 1 9 are shown in Table (V).

Example 20: Herbicidal application during post-emergence of the plant species A number of seeds determined as a function of the plant species and seed size are seeded in 9 X 9 X 9 cm pots filled with light agricultural soil.

The seeds are then covered with a layer of soil approximately 3 mm thick and the seed is allowed to germinate until it produces a plantlet at the suitable stage. The treatment stage in the case of the graminaceous plants is the "second leaf being formed" stage. The suitable stage for soya is the "first trifoliate leaf open stage". The treatment stage for the other dicotyledon plants is the "cotyledon leaves open, first true leaf being developed" stage.

The pots are then treated by spraying with a spraying mixture in a quantity corresponding to a volume application dose of 500 1 /ha and containing the active ingredient at the required concentration.

The spraying mixture was prepared in the same manner as in Example 1 9.

The applied dose of active ingredient was from 0.125 to 2 kg/ha, depending on the concentration of the active ingredient in the spraying mixture.

The treated pots are then placed in troughs intended to receive the moistening water, by subirrigation, and are kept for 21 days at ambient temperature under 70% relative humidity.

After 21 days, the results are evaluated as shown in Example 19. The results obtained in this Example 20 are shown in Table (V).

The plant species employed in Examples 1 9 and 20 are combined in Table (VI).

The products according to the invention exhibit, in general, an outstanding antidicotyledon activity during pre-emergence, but above all during post-emergence, towards major adventitious plants in soya, such as Abutilon, Ipomea or Xanthium.

For their use in practice, the compounds according to the invention are in general employed in the form of compositions which are also included within the scope of the present invention.

These compositions usually incorporate, in addition to the active ingredient (compound of formula 1), one or more solid or liquid, agriculturally acceptable carriers (or diluents) and one or more surface-active agents which are also agriculturally acceptable. If necessary, they can also contain various additives which are also agriculturally acceptable.

Usually, these compositions contain approximately from 0.05 to 99% by weight of active ingredient, if appropriate, approximately 0.1 to 20% by weight of one or more surface-active agents and approximately 1 to 99.95% by weight of one or more liquid or solid carriers (or diluents).

Solid carriers which may be employed are natural or synthetic silicas such as, for example, diatomaceous earth; clays and natural or synthetic silicates such as, for example, talc, attapulgite, vermiculite, kaolinites, montmorillonite, calcium and aluminium silicates; calcium carbonates; natural or synthetic resins such as polyvinyl chloride, and the like.

Liquid carriers which may be employed are water; alcohols such as, e.g., isopropanol and glycols; ketones such as, e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like; ethers; aromatic or arylaliphatic hydrocarbons such as benzene, toluene, xylenes, petroleum fractions, for example kerosene, chlorinated hydrocarbons such as carbon tetrachloride, perchloroethylene, and the like.

When the carrier is water or a common organic solvent, the compositions according to the invention advantageously incorporate a surface-active agent, in addition to the active ingredient.

The surface active agent may be an emulsifying, dispersing, deflocculating or wetting agent, of the ionic or non-ionic type.

Surface active agents which may advantageously be employed are polycondensates of ethylene oxide with fatty acids or with fatty alcohols or with substituted phenols (particularly with alkylphenols or arylphenols) or with fatty amides, or with fatty amines. It is also possible to use advantageously esters of fatty acids and of sorbitan, sucrose derivatives, alkali metal salts or alkaline-earth metal salts of lignosulphonic acids, alkylarylsulphonic acids; salts of esters of sulphosuccinic acids; alkylbetaines or sulphobetaines, and the like.

The publication "Mc Cutcheon's Detergents and Emulsifiers 1975 Annual" MC Publ. Corp.

Ridgewood, New Jersey, USA describes numerous surface-active agents and gives recommendations for their use.

US Patent No. 3,713,804 describes numerous anionic or cationic or non-ionic surface-active agents which may be employed in agriculture. The surface-active agent to be employed in the compositions according to the invention can advantageously be chosen by the expert from the compounds or families of compounds described in these two documents or elsewhere.

In addition to the active ingredient, the carrier and the surface-active agent, the compositions according to the invention may contain other additives such as non-surface-active dispersing agents, peptising agents, protective colloids, thickeners, adhesives increasing rain resistance, stabilisers, preserving agents, corrosion inhibitors, colorants, sequestering agents, anti-foaming agents, anti-caking agents, anti-freezes, and the like.

The compositions according to the invention may be in various solid or liquid forms.

Among solid forms of compositions may be mentioned dusting powders (with a content of active ingredient which may go up to 100%) and granulates and microgranulates, particularly those produced by extrusion, by densifying, by impregnation of a granular carrier, by granulation starting from a powder (the content of active ingredient in these granulates being between 1 and 80% in the latter cases). These solid forms are in general employed dry, without further dilution.

Among liquid forms of compositions, or those intended to form liquid compositions during the application, mention may be made of wettable powders (or spraying powders), emulsifiable solutions or concentrates, flowables, solutions, in particular water-soluble concentrates, emulsons and dispersions.

The dusting powders usually contain from 0.1 to 5% by weight of active ingredient, an inert carrier which may be an impregnation carrier such as a silica and, when appropriate, from 0 to 10% by weight of one or more stabilisers and/or other additives such as penetrating agents, adhesives, anti-caking agents or colorants. They are usually prepared by premixing the active ingredient with the inert carrier and the mixture is then ground in a mill.

The granulates and micro-granulates, generally with a low content of active ingredient, may be manufactured beforehand and then impregnated, or bulk-manufactured, e.g. by spraying or extrusion. In the latter case, they require the addition of binders and surface-active products to ensure that they disintegrate rapidly on the ground. In general, they contain from 0.5 to 10% by weight of active ingredient, from 0 to 10% by weight of additives such as stabilisers, slowrelease modifying agents, binders and solvents.

The wettable powders (or spraying powders) are usually prepared so that they contain 20 to 95% of active ingredient, and they usually contain, in addition to the solid carrier, from 0 to 5% of a wetting agent, from 3 to 10% of a dispersing agent and, when required, from 0 to 10% of one or more stabilisers and/or other additives, such as peiietrating agents, adhesives, anticaking agents, colorants, and the like.

By way of example, here is a composition of a wettable powder of 50% strength: active ingredient 50% sodium lignosulphonate 5% sodium dibutylnaphthalenesulphonate 1 % -clay (kaolin) 44% Another example of a wettable powder has the following composition: active ingredient 50% sodium and/or calcium lignosulphonate (deflocculant) 5% -isopropylnaphthalenesulphonate (anionic wetting agent) 1 ,h -anti-caking silica 5% -kaolin (filler) 39% To obtain these spraying powders or wettable powders the active ingredient is mixed thoroughly in suitable blenders with the additional substances and is ground using mills or other suitable grinders. Spraying powders are thus obtained the wettability and the suspendability of which are advantageous; they may be suspended using water at any required concentration and this suspension may be used very advantageously in particular for application on plant leaves.

The emulsifiable solutions or concentrates contain the active ingredient dissolved in a solvent (usually an aromatic hydrocarbon) and, in addition, when necessary, an auxiliary solvent or cosolvent which may be a ketone, an ester, an ether oxide, or the like.

In general, they contain from 5 to 60% by weight/volume of active ingredients, from 2 to 20% by weight/volume of an emulsifying agent and may be prepared, e.g., by dissolving the active ingredient in the solvent or in the mixture of solvents and emulsifiers, with effective stirring and with heating or cooling.

Using these emulsifiable solutions or concentrates, it is possible to obtain, by dilution with water, emulsions of any required concentration which are particularly suitable for using the compounds according to the invention.

The flowables consist of a suspension of fine solid particles of the active ingredient in water or a non-solvent oil, which is prepared so as to produce a stable fluid product, which does not settle. They usually contain from 10 to 75% by weight of active ingredient, from 0.5 to 15% of surface-active agents, from 0.1 to 10% of thixotropic agents, from 0 to 10% of suitable additives such as anti-foaming agents, corrosion inhibitors, stablisers, penetrating agents and adhesives and, as a carrier, water or an organic liquid in which the active ingredient is poorly soluble or insoluble; some organic solids or inorganic salts may be dissolved in the carrier to help prevent settling or as antifreezes for water.

These concentrated suspensions are prepared by grinding the active ingredient very finely, then dispersing the active ingredient in the liquid carrier containing the auxiliary ingredients, then the dispersion produced is ground in a bead mill. Suspensions of any required concentration may be obtained from the flowables by dilution with water.

These aqueous suspensions or emulsions of the active ingredient, described earlier, e.g. the compositions produced by diluting with water a wettable powder, or an emulsifiable concentrate, or a flowable, are included in the general scope of the compositions according to the invention.

The emulsions may be of the water-in-oil or oil-in-water type and may have a thick consistency such as that of a "mayonnaise".

The present invention relates, finally, to a process for selective weeding of crops, particularly rice, soybean and wheat crops. This process is one in which a quantity, effective against weeds, but not phytotoxic to crops, of a compound according to formula (I) is applied to the soil, during pre-emergence of the said crops. The quantity of active ingredient to be employed may vary depending on the compound employed, the types of crop, the climatic conditions, and the nature of the weeds to be destroyed.

TABLE (I)

COMPOUND X W R Y. M.p. ( C) IR or NMR SPECTRAL NO. (%) CHARACTERISTICS 1 CF3 H H 38 173 2 CF3 NO2 H 47 142 3 CF3 NO2 Na 75 < 250 4A CF3 N02 HI3 63 90- 92 5 Cl NO2 -CH3 66 115 6 CF3 NO2 -C2H5 45 66-67 7 CF3 NO2 i-C3H7- 37 Oit 8 CF3 NO2 -CH2COOC2H5 50 127 9 CF3 NO2 CH3 65 Oit NMR 1.25 - 2.00 #CHCOOC2H5 (R,S) 4.23 - 5.68 10 CF3 NO2 -COOC2H5 95 140 11 CF3 NO2 -CH2CH2COOC2H5 65 132 12 CF3 NO2 CH3 66 Oil NMR 2.03 - 3.75 #CHCOOCH3 (R,S) 5.74 13 CF3 NO2 C2H5 71 Oil NMR 0.98 - 2.47 #CHCOOCH3 (R,S) 3.78 - 5.53 14 CF3 NO2 -CH2COOCH3 61 132 15 CF3 NO2 -CH2OCH2CH2OCH3 47 Oit IR 1588, 1536, 1327, 1270, 1130, 1082 In Table (I) the spectral characteristics which are given are as follows: -where the symbol is IR, these are infrared absorption bands, in cm-, -where the symbol is NMR, these are proton chemical shifts, the measurement being made in deutrerated chloroform in the presence of tetramethylsilane as reference.

TABLE (II) Herbicidal activity in a greenhouse during pre-emergence Percentage relative to the controls 100: identical to the control-no herbicidal activity O : total herbical activity PLANTS

Compound No. Dose TRIT ALOP AVEN LENS RAPH kg/ha 1 10 32 36 55 85 100 2 1 70 29 75 29 7 4A 2.2 34 0 11 35 26 6 1 80 14 76 100 7 1 83 32 66 41 100 8 1 80 63 90 100 1 10 1 100 100 100 46 13 Compound No. Dose BETA LACT FAG AMA kg/ha 1 10 37 100 60 IS 2 I 1 3 16 100 0 4A 2.2 44 0 1 0 6 1 56 2 60 0 7 1 100 100 100 0 8 1 5 0 75 0 10 1 3 13 60 0 TABLE (111) Herbicidal activity in a greenhouse during post-emergence Percentage relative to the controls 100% : identical to the control-no herbicidal activity 0% total herbicidal activity PLANTS

Compound No. Dose TRIT ALOP AVEN LENS kg/ha 1 10 100 100 100 75 2 1 . 64 56 73 32 4A 2.2 39 0 22 17 6 1 77 10 73 7 1 . 100 34 80 67 8 1 83 75 83 8 10 1 100 88 100 54 Compound No. Dose RAPH BETA LACT FAG kg/ha 1 10 0 57 100 2 1 0 10 0 0 4A 2.2 0 0 0 0 1 9 3 4 0 7 1 . 25 16 0 6 8 l 0 0 2 0 10 1 6 4 10 1 TABLE (IV) Herbicidal activity, in a greenhouse, during post-emergence Percentages relative to the controls 100: identical to the control-no herbicidal activity 0: total herbicidal activity Compound No. 3 No.4A No. 8 Dose kg/ha 0.5 0.5 0.5 Oryza sativa 54 88 Triticum vulgare - 100 61 85 Alopecurus myosuroïdes 13 67 Echinochloa crus-galli 34 46 Setaria viridis 96 0 15 Abutilon theophrasti 50 0 47 Sida spinosa 20 20 Chrysanthemum annuum 23 8 0 Matricaria matricarioïdes 15 15 Veronica persica 0 0 Plantago lanceolata 0 4 Amarantus Caudatus 0 0 Solanum nigrum 8 0 0 Sinapis alba 0 0 Convolvulus arvensis 0 3 Stellaria media 7 54 TABLE (V)

Compound Dises PRE-EMERGENCE POST-EMERGENCE No in kg/ha DCH LOL A@U IPO SIN X@V @@@ SOY DCH LOL ABU IFO S@@ @@@ @@@ CoY 2 100 20 100 50 100 100 0 50 60 20 95 100 100 100 0 0 9 0.5 80 0 100 10 100 30 0 0 30 20 90 100 100 100 0 0 0.125 30 0 80 0 80 0 0 0 20 0 80 100 90 30 0 0 2 0 30 100 50 100 100 0 0 90 30 100 100 100 100 0 0 11 0.5 0 20 100 30 100 100 0 0 30 0 100 100 100 50 0 0 0.125 0 0 100 0 80 0 0 0 20 0 80 100 100 50 0 0 2 100 100 100 100 100 100 40 0 100 30 100 100 100 100 20 30 12 0.5 100 50 100 30 100 50 0 0 100 20 100 100 100 100 0 0 0.125 80 20 100 0 100 0 0 0 90 20 100 100 100 100 0 0 2 80 0 100 30 100 50 0 0 30 0 90 100 100 100 0 50 13 0.5 20 0 50 30 100 0 0 0 30 0 90 100 100 100 0 50 0.125 0 0 80 0 100 0 0 0 20 0 30 100 100 100 0 0 2 100 0 90 70 100 30 0 0 80 0 30 100 100 100 0 0 14 0.5 50 0 0 0 100 0 0 0 20 0 20 100 100 100 0 0 0.125 0 0 0 0 95 0 0 0 0 0 0 90 95 100 0 0 Notation: O:identical to the control 100::complete destruction of the plants TABLE (VI)

American Latin Abbrevi name name at ion Crop Wheat WHE Soybean SOY Weeds Barnyardgrass Echinochloa ECH crus-galli Velvet leaf Abutilon ABU theophrasti Cocklebur Xanthium XAN pennsylvanicum Wild mustard Sinapis arvenis SIN Morning glory Ipomea purpurea' IPO (annual) Rye-grass Lolium multi LOL florum Cocklebur Xanthium XAN pennsylvanicum Compounds of general formula I which are of particular interest include the following compounds, their tautomers, their enantiomeric forms and their salts: 5-[3'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 1) 5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazol (Compound of Example 2) Sodium salt of 5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl[tetrazol (Compound of Example 3) 2-methyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 4A) 1-methyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 4B) 2-methyl-5-[3'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole 2-methyl-5-[2'-nitro-5'(2'', 4''-dichlorophenoxy)phenyl]tetrazole (Compound of Example 5) 2-ethyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenol]tetrazole (Compound of Example 6) 2-isopropyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 7) 2-ethoxycarbonylmethyl-5-[2'-nitro-5'-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 8) (R, S)-2-(1 .ethoxycarbonylethyl-5-[2 '-nitro-5'-(2 "-chloro-4".trifluoromethyl phenoxy)phenyl]tetrazole (Compound of Example 9) 2-ethoxycarbonyl-S-[2'-nitro.5'-(2".chloro.4"-trifluoromethylphenoxy)phenyl].tetrazole (Compound of Example 10) 2-(2-ethoxycarbonylethyl)-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 11) (R, S)-2-(1 -methoxycarbonylethyl)-5-[21-nitrn-5'-(211.chloro.4-tritluoromethylphenoxy)phenyltetrn.

zole (Compound of Example 12) (R, S)-2-(1 -methoxyearbonylpropyl)-5-[2'-nitro-5 '-(2"-chloro-4"-trifluoromethylphenoxy)phenyl]tet- razole (Compound of Example 13) 2-methoxyCarbonylmethyl-5-[2'-nitro-5'-(2"-chloro-4"-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 14) 2-(2-methoxyethoxymethyl).5.[2'-nitro-5'.(2 "-chloro-4"-trifluoromethylphenoxy)phenyl]tetrazole (Compound of Example 15) 2-(1-methoxycarbonylethyl)-5-[2'-nitro-5'-(3''-chloro-5''-trifluoromethylpyrid-2''-yloxy)phenyl]tetrazole and more particularly the compounds of Examples 1, 2, 3, 4A, 6, 7, 8, 9, 10, 11, 12, 13 and 14.

Compounds of general formula I wherein R represents the hydrogen atom, an alkyl, alkoxycarbonylalkyl, alkoxycarbonyl or alkoxyalkoxyalkyl group in which alkyl moieties contain from 1 to 4 carbon atoms, or an alkali metal salt when R is hydrogen, are preferred.

Claims (40)

1. A product which has the formula:

in which: X denotes a halogen atom or a lower alkyl radical optionally substituted by one or more halogen atoms, Y denotes a hydrogen or halogen atom, or a CF3, CN, NO2 or CH3 radical, D denotes the nitrogen atom or the radical -C(Z) = in which Z denotes a hydrogen or halogen atom, W denotes a hydrogen or halogen atom or the nitro radical, R denotes the hydrogen atom, or a halogen atom, or an aliphatic or aromatic, alkylthio, amino, acyl, alkylsulphonyl, arylsulphonyl, hydroxy or cyano radical, optionally substituted, if appropriate, with one or more atoms or radicals selected from halogen, alkoxy, alkoxyalkoxy, hydroxy, alkyl, lower acyl, carboxyl and salts or esters of this carboxyl group, and its agriculturally acceptable salts.

2. A product according to claim 1, in which R denotes the hydrogen atom or a halogen atom, or a radical chosen from the following radicals: optionally substituted alkyl; optionally substituted aryl; lower alkenyl; lower alkynyl; optionally substituted lower alkylthio, amino unsubstituted or substituted by one or two lower alkyl or acyl radicals; -CO-R' in which R' denotes a substituent chosen from OH, lower alkoxy, aryloxy and optionally substituted amino; -SO2-R" in which R" denotes a substituent chosen from alkyl and aryl radicals; -OH and -CN; and the agriculturally acceptable salts of this product.

3. A product according to claim 1 or 2, in which: X is CF3, Y is Cl, D is -CH W is nitro or H, and R denotes an optionally substituted alkyl radical.

4. A product according to claim 1, wherein R represents the hydrogen atom or an alkyl, alkoxycarbonylalkyl, alkoxycarbonyl or alkoxyalkoxyalkyl group in which alkyl moieties contain from 1 to 4 carbon atoms, or an alkali metal salt when R is hydrogen.

5. 5-[3'-(2"-chloro-4"-trifl uoromethylphenoxy)phenylltetrazole.

6. 5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

7. Sodium salt of 5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

8. 2-methyl-5-[2'-nitro-5'-(2"-chloro-4"-trifluoromethyl phenoxy)phenyljtetrazole.

9. 2-ethyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

10. 2-isopropyl]5-[2'-nitro-5-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

11. 2-ethoxycarbonylmethyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

12. 2-( 1 .ethoxycarbonylethyl-5.[2'-nitro-5'-(2".chloro.4".trifluoromethylphenoxy)phenyl]tet- razole.

13. 2-ethoxycarbonyl-5-[2'-nitro-5'-(2''-chloro-4'-trifluoromethylphenoxy)phenyl]tetrazole.

14. 2-(2-ethoxycarbonylethyl)-5-l[2'.nitro.5'-(2 "-chloro.4".trifluoromethylphenoxy)phenyl]tet- razole.

15. 2-(1-methoxycarbonylethyl)-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole and its enantiomeric forms.

16. 2-(1-methoxycarbonylpropyl)-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole.

17. 2-methoxycarbonylmethyl-5-[2'-nitro-5-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tet razole.

18, 1-methyl-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole, 2-methyl5-[3'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole and 2-methyl-5-[2'-nitro-5'-(2'', 4'' dichlorophenoxy)phenyl]-tetrazole.

19. 2-(2-methoxyethoxymethyl)-5-[2'-nitro-5'-(2''-chloro-4''-trifluoromethylphenoxy)phenyl]tetrazole and 2-( 1 methoxycarbonylethyl).5.[2'-nitro-S'.(3".chloro.5"-trifluoromethylpyrid-2"-yI- oxy)phenyl]tetrazole.

20. A process for preparing a product according to one of claims 1 to 4, which comprises reacting a phenyltetrazole of the formula (II)

in which W and R have one of the meanings given in claims 1 to 4 and A denotes the hydroxy radical or a halogen atom, with a compound of the formula (III)

in which X, Y, and D have one of the meanings shown in claims 1 to 4, and B denotes a halogen atom or hydroxy radical, it being understood that B is chosen to be different from A and that the reagent containing the hydroxyl group may be in a phenate or pyrid-2-ylate form.

21. A process for the preparation of a product of the formula (I)

in which W denotes a halogen atom and X, Y, D and R have one of the meanings shown in claims 1 to 4, which comprises halogenating a compound of the formula (IV)

in which X, Y, D and R have one of the meanings shown in claims 1 to 4.

22. A process for preparing a product of the formula:

in which X, Y, D and R have one of the meanings shown in claims 1 to 4, which comprises nitrating a compound of the formula (IV):

in which X, Y, D and R have one of the meanings shown in claims 1 to 4.

23. A process for preparing a product of the formula (VII)

in which X, Y and D have one of the meanings shown in claims 1 to 4, comprising in reacting NaN3 with the nitrile of the formula (Vi):

in which X, Y, and D have one of the meanings shown in claims 1 to 4.

24. A process for the preparation of a salt of a product of the formula (IX):

in which X, Y, D and W have one of the meanings shown in claims 1 to 4, comprising in reacting this compound of the formula (IX) with a suitable base, preferably sodium hydroxide.

25. A process for the preparation of a compound of the formula (I)

in which R, X, Y, D and W have one of the meanings shown in claims 1 to 4 and R is other than the hydrogen atom, which comprises reacting a compound of the formula (VIII) R-T (VIII) in which R has the same meaning as before but not H, and T is a leaving group, with the compound of the formula (VIIA)

in which X, Y, D and W have one of the meanings shown in claims 1 to 4.

26. A process for the preparation of products of the general formula depicted in Claim 1, wherein the various symbols are as defined in Claim 1, and agriculturally acceptable salts thereof substantially as hereinbefore described, with especial reference to any one of Examples 1 to 15.

27. Aryloxybenzoic acid derivatives of the general formula depicted in Claim 1, wherein the various symbols are as defined in Claim 1, and agriculturally acceptable salts thereof when prepared by the process claimed in any one of Claims 20 to 26.

28. A herbicidal composition which comprises as active ingredient at least one product of the general formula depicted in Claim 1, wherein the various symbols are as defined in Claim 1, or an agriculturally acceptable salt thereof in association with one or more solid or liquid carriers acceptable in agriculture and/or one or more surface-active agents acceptable in agriculture.

29. A herbicidal composition according to Claim 28 which contains from 0.05 to 99% by weight of product(s) of the general formula depicted in Claim 1 wherein the various symbols are as defined in Claim 1, from 0.1 to 20% of surface active agent and from 1 to 99.95% by weight of one or more liquid or solid carriers.

30. A herbicidal composition according to Claim 28 or 29 in which the aryloxybenzoic acid derivative incorporated in the composition is a compound claimed in any one of Claims 2 to 1 9.

31. A herbicidal composition according to Claim 28 substantially as hereinbrefore described.

32. A method of controlling the growth of weeds at a locus which comprises applying to the locus a herbicidally effective amount of a product of the general formula depicted in Claim 1, wherein the various symbols are as defined in Claim 1 or an agriculturally acceptable salt thereof.

33. A method according to Claim 32 in which the aryloxybenzoic acid derivative is applied to area used, or to be used for growing crops.

34. A method according to Claim 33 in which the aryloxybenzoic acid derivative is applied to a crop-growing area at a rate sufficient to control the growth of weeds without causing substantial permanent damage to the crop.

35. A method according to Claim 33 or 34 in which the crop is rice, soya or wheat.

36. A method according to Claim 35 in which the crop is soya.

37. A method according to any one of Claims 33 to 36 in which the aryloxybenzoic acid derivative is applied at a rate between 0.01 and 5kg per hectare.

38. A method according to Claim 37 in which the aryloxybenzoic acid derivative is applied at a rate between 0.1kg and 2kg per hectare for the control of weeds in an area to be used for growing soya before emergence of both the crop and weeds.

39. A method according to any one of Claims 32 to 38 in which the aryloxybenzoic acid derivative is a compound claimed in any one of claims 2 to 1 9.

40. A method according to claim 32 substantially as hereinbefore described.