CA1093093A - Chloromethanesulphonic acid anilides and their use as herbicides - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A novel chloromethanesulphonic acid 2-trifluoromethyl anilide of the formula

Description

~O~V~
B~CKGROUND OF THE INVENTION

;Field Of The Invention This invention relates to new cloromethanesulphonic acid anilides, methods for their preparation and their use as herbicides.

Discussion Of The Prior Art .. ..
1.0 It has already been disclosed in German Offenlegungs-schrift 2,551,027 that methane-sulphonic acid 2-trifluoromethyl-4-methylthio-anilide, methanesulphonic acid 2-trifluoromethyl-4-methylsulphinyl-anilide and methane-sulphonic acid ~-tri-1uoromethyl-4-sulphonyl-anilide are suitable for combating weeds. However, the activity and the selectivity of these substances are not always completely satisfactory, especially at low application rates.

SUMMAR~ OF THE INVENTION

Broadly this invention contemplates a novel chloro-me~hanesulphonic acid 2-trifluoromethyl anilide of the formula Cl-C~2-S02-NH ~ -S ()n ~Q 3 (I) wherein n represents 0, 1 or 2. The novel chloromethanesulphonic acid 2-trifluoromethyl-anilides have been found to be especially 1~ ~ 3~

effective herbicides par icularly in standing fields of cotton.
The chloromethanesulphonic acid 2-trifluoromethyl anilides can be prepared by several alternate means, According to one embodiment a 2-trifluoro-4-methylthio-aniline of the formula H2N~3-SCH3 (II) is contacted with chloromethanesulphonyl chloride of the formula Cl-CH2-S02-Cl ~III) in the presence of an acid acceptor and, if desired, in the presence of a diluent. The resultant chloromethanesulphonic acid 2-trifluoromethyl-4-methylthio-aniline can thereafter be oxidized by contacting the same with a source of oxygen, if desired in the presence of a diluent.
According to a second embodiment oxidized forms of the compound of the invention are prepared by a two-step process comprising:
A. contacting a 2-trifluoromethyl-4-methylthio-aniline of the formula H2N~)-SCH3 F3C~ (II) with oxygen under oxidation conditions, if desired in the presence of a diluent to thereby form a compound o~ the formula 2N ~ -S ~)x CH3 (IV) 3~9;~

wherein x represents 1 or 2; and B. thereaf~er contacting said H2N ~ ~ )x CH3 ~IV) with chloromethanesulphonyl chloride of the formula Cl-CH2-SO -Cl tIII~
in the presence of an acid acceptor and, if desired, in the presence of a diluent.
Surprisingly, the chloromethanesulphonic acid 2-trifluoromethyl-anilides according to the invention exhibit a higher herbicidal activity and a better selectivity than methanesulphonic acid 2-trifluoromethyl-4-methylthio-anilide, methanesulphonic acid 2-trifluoromethyl-4-methylsulphinyl-anilide and methanesulphonic acid 2-trifluoromethyl-4-methylsulphonyl-anilide, which are compounds which are known from the state of the art and are chemically the most closely related active compounds having the same type o action. The substances according to the invention thus represent a valuable enrichment of the art.
If 2-trifluoromethyl-4-methyl-thio-aniline and chloromethanesul-phonyl chloride are used as the starting materials and hydrogen peroxide is used as the oxidising agent, the course of the reaction according to process variants ~a) and Cb) can be represented by the following equations:

H 2N~ -SCH 3 Variant ( a ) )~

+2 C1CH2SO2Cl (ClC~2S02) 2N~ SCH3

- 2 H Cl 3 l F3 ~¦, KOH

+ ClCH2S2Cl ClCH2S02-NH-~sCH3 - H Cl¦ F3 ¦ H202.

ClCH2S02-NH~_So-cH3 \¦, H202 ClCH 2So2-NH-~3So2CH3 ,~

N~3-SCH 3 HaN-~3soCH3 -il Cl ClCH2S02 NH~3-soc~3 ~22 + ClcH2$o2cl ClCH 802; NH4-3 S2CH3 ~2 ~ _~
H2N~-SO2CH3 -H Cl F3C

10~3093 The compounds of the formulae ~II) and ~III) required as starting materials are known. The preparation thereof is described in German Offenlegungsschrift 25 51 027, published May 26, 1976.
All the customary acid-binding agents can be used as acid ac-ceptors in the reaction of 2-trifluoromethyl-4-methylthio-aniline with chloromethanesulphonyl chloride according to an embodiment of the invention.
Particularly preferred are alkali metal hydroxides, such as sodium hy-droxide and potassium hydroxide; alkali metal carbonates, such as sodium carbonate and potassium carbonate; alkali metal alcoholates, such as sodium methylate and sodium ethylate; and aliphatic, aromatic or heterocyclic amines, such as, for example, triethylamine, dimethylamine, dimethylanilines dimethylbenzylamine and pyridine.
All inert organic solvents can be used as the diluent in the reaction of 2-trifluoromethyl-4-methylthioaniline with chloromethanesulphonyl chloride, especially aliphatic or aromatic hydrocarbons, such as petroleum ether, benzine, benzene, toluene and xylene; chlorinated aliphatic or aromatic hydrocarbons, such as methylene chloride, chloroform, carbon tetrachloride and chlorobenzene; ethers, such as diethyl ether, dibutyl ether, tetrahydrouran and dioxane; and ketones, such as acetone. Moreover, water can also be employed as the diluent.
The reaction tempexatures in the reaction of 2-trifluoromethyl-4-methylthio-aniline with chloromethanesulphonyl chloride can be varied within a relatively wide range. In 10~30~3 general, ~he reaction is carried out at temperatures of from 0C to 80C, preferably from 10C to 50G.
In carrying out the reaction of 2-trifluoromethyl-4-m~ethylthio-aniline with chloromethanesulphonyl chloride, 1 to

3 moles of chloromethanesulphonyl chloride are generally em-ploye~ per mole of 2-trifluoromethyl-4-methylthio-aniline.
When chloromethanesulphonyl chloride is used in more than the equimolar amount, in addition to chloromethanesulphonic acid 2-trifluoromethyl-4-methylthio-anilide, N,N-(bis-chloro-methylsulphonyl)-2-trifluoromethyl-4-methylthio-aniline is also formed. However, the latter compound can be converted into the desired product by treatment with strong bases, such as, for example, potassium hydroxide.
The re~ction product is isolated by customary methods.
In general, the procedure is to add a dilute strong acid to the reaction mixture. In some cases the reaction product thereby separates out in the crystalline form, If there is a large amount of N,N-(bis-chloromethylsulphonyl)-2-trifluoro-methyl-4-methylthio-sniline in the reaction mixture, after adding dilute acid ~he mixture i8 extracted with an organic solvent which i6 immiscible with water, the solvent is removed and the residue is treated with a strong base and subsequently acidified.
All the customary oxidizing agents which release oxygen can be used in ~he oxidation of chloromethanesulphonic acid 2-tri~luoromethyl-4-methylthio-anilide according to an embodi-ment of the invention, especially hydrogen peroxide, peracetic acid and m-chlorobenzoic acid.

10 ~ 3~ ~ ~

In carrying out this oxidation, any of the organic solvents which can customarily be used for oxidations of this type can be employed as the diluent, especially glacial acetic acid and methylene chloride.
The reaction temperatures in the oxidation of chloro-methanesulp~onic acid 2-trifluoromethyl-4-methylthio-anilide according to t~e invention can be varied within a relatively wide range. In general, the reaction is carried out at temperatures of from 0C to 120C, preferably of from 50C
to 100C.
In carrying out the oxidation an equimolar amount or sn excess of oxidizing agent with respect ~o the chloromethane-sulphonic acid 2-trifluoromethyl-4-methylthio-anilide are generally employed~ depending on whether the sulphinyl or sulphonyl compound of the formula (I) is to be synthesized.
Working up is carried out in accordance witll customary methods, In general, the procedure is to add water to the mixture af~er the reaction has ended. The reaction product thereby frequently separates out immediately in the crystalline form. If this is not the case, the reaction mixture is ex-tracted with an organic solvent which is immiscible with water, the phases are separated and the solvent is removed.
Any of the customary oxidizing agents which release oxygen can also be used in carrying out sn embodiment of the invention where 2-trifluoromethyl-4-methylthio-aniline is initially oxidized prior to reaction of the oxidized product with chloromethanesulphonyl chloride. Especially contemplated are those oxidizing agents which have already been mentioned 10 ~ 3~

as preferred in connection wi~h oxidation of a chloromethane sulphonic acid 2-trifluoromethyl-4-methylthio-anilide.
In this oxidation also, any of the solvents which can customarily be used for reactions of this type can be employed as the diluent, especially glacial acet~c acid and methylene chloride, The reaction temperatures in carrying out this latter described oxidation can be varied within a fairly wide range.
In general, the reaction is carried out at temperatures of from 0C to 120C, preferably of from 50C to 100C. In carrying out such oxidation the procedure is the same as in the corresponding reaction step for oxidation of the 2-tri-fluoromethyl-4-methylthio-aniline (II).
All the cus~omary acid acceptors can be used in the lS reaction of a compound of the formula (IV) with chloro-methanesulphonyl chloride according to an embodim,ent of the invention expecially those mentioned above.
All inert organic solvents can also be used in the reaction of compound (IV) with chloromethanesulphonyl chloride especially those solvents w~ich have already been mentioned a8 preferred in connection with t~e alternate embodiment. Fur-therm~e, water can al~o be used as the diluent.
The temperatures in the reaction of 8 compound o~
the formula (IV) with chloromethanesulphonyl chlorids can al30 be varied within a relatively wide ran~e. In ~eneral, the reaction i9 carried out at temperatures o~ ~rom 0C
to 80C, preferably of from 10C to 505.
In carrying out the reaction of a compound of the formula (IV) with chloromethanesulphon,yl chloride, l to 3 _9 10~30~3 moles of chloromethanesulphonyl chloride are generally employed per mole of an aniline of the formula ~IV). The reaction products are isolated in accordance with the methods which have already been described in con-nection with the corr~sponding reaction of process variant (a).
The active compounds according to the inv~ntion influence plant growth and can therefore be used as defoliants, desiccants, agents for destroying broad-leaved plants, germination inhibitors and, especially, as weedkillers. By "weeds" in the broadest sense there are meant plants grow-ing in places where they are not desired. Whether the compounds according to the invention act as total herbicides or selective herbicides depends essentially on the amount used.
The active compounds according to the present invention may be used, for example, to combat the following plants:
dicotyledon weeds such as mustard ~Sinapis), cress ~Lepidium), bed straw C~ , chickweed ~Stellaria), camomile ~MatricariaJ , mayweed ~Anthemis), gallant soldier ~Galinsoga), gooseoot ~Chenopodium), annual nettle ~Urtica), groundsel ~Senecio), pigweed ~Amaranthus), purslane ~Portu-lac_~, cocklebur ~Xanthium), bindweed ~Convolvulus~, morning glory ~Ipomoea), knotweed ~Polygonum), sesbania tSesbania), ragweed ~Ambrosia), spear thistle ~Cirsium~, common thistle ~ ~ , sow thistle tSonchus), field cress ~Rori~ , toothcup ~Rotala), alse pimpernel ~Linderna), deadnettl~ (Lamium), speedwell ~Veronica), mallow tAbutilon), emex ~Emex), thornapple (Datura), violet ~ ~ , hemp-nettle ~Galeopsis), poppy ~Papaver) and knapweed ~Centaurea) and nightshade ~Solanuml; and monocotyledon weeds such as barn-yard grass ~Echino-10~ 93 chloa), foxtail (Setaria), wild mille~ (Panicum), crabgrass ( igitaria), timothy (Phleum), blue~rass (Poa), fescue ( estuca), goosegrass (Eleusine), signalgrass (Brachiaria), ryegr.~ss (Lolium), cheat (Bromus), oats (Avena), flatsedge (cyperus)~ sorghum ~Sor~hum), quackgrass (Agropyron), Ber-muda gras~ (Cynodon), Monocharia, ~imbristylis (Fimbristylis), arrowhead (Sagitt~ria), spikerush (Eleocharis), bu~rush (Scirpus), paspalum (PasPalum), Ischaemum, gooseweed (Sphenoclea), crowfoot grass (Dactyloctenium), redtop (Agrostis), meadow foxtail (Alopecurus) and silky bent-grass (Apera).
The active compounds accordin~ to the present invention may be used, for example, as selective herbicides in the following cultures:
dicotyledon cultures such as cotton (Gossypium), soya bean (Glycine), beet ( et_), carrot (Daucus), bean (Phaseolus), pea (Pisum), potato (Solanu~ lax (Linum), sweet potato (Ipomoea), broad bean (Vicia), tobacco (N'cotiana), tomato (Lycopersicon), groundnut (Arachis), cabbage (Brassica), lettuce (Lactuca), cucumber (Cucu~is) and marrow (Cucurbita); and monocotyledon cultures such as rice ( ~ ), maize (Zea), wheat (Triticum), barley (Hordeum), oats (Avena), rye (Secale), sorghum (Sorghum), millet ~Panicum), sugar cane (Saccharum), pineapple (Ananas), asparagus (Aspara~us) and onion (Allium).
However, the use Or the active compounds according to the invention is in no way restricted to these plants or even to the indicated genera but also embraces other plants, in the same way.
Depending on the concentration, the compounds can be used ~or the total combating Or weeds, ~or example on industrial terrain and railway tracks and on paths and squares with and without trees. Equally, the compounds 10~930~3 can be employed for combating weeds in perennial cultures, for example forestry plantings, decorative tree plantings, orchards5 vineyards, citrus groves, nut orchards, banana plantations, coffee plantations, tea plant-ations, rubber plantations, oil palm plantations, cacao plantations, soft fruit plantings and hopfields, and for the selective combating of weeds in annual cultures.
The chloromethanesulphonic acid 2-trifluoromethyl-anilides ac-cording to the invention are especially suitable for the selective com-bating of weeds - above all for combating grass-like weeds - in standing crops of cotton.
The active compounds according to the instant invention can be utilized, if desired, in the form of the usual formulation or compositions with conventional inert ~i.e. plant compatible) diluents or extenders, i.e. diluents, carriers or extenders of the type usable in conventional pesticide formulations or compositions, e.g. conventional pesticide dis-persible carrier vehicles such as gases, solutions, emulsions, wettable powders, suspensions, powder dusting agents, foams, pastes, soluble powders, granules, aerosols, suspension - emulsion concentrates, seed-treatment powders, natural and synthetic materials impregnated with active compound, very fine capsules in polymeric substances and in coating compositions, for use on seed, and formulations used with burning equipment, such as fumigating cartridges,fumigating cans, fumigating coils and the like, as well as ULV cold mist and warm mist formulations.
These are prepared in known manner, for instance by extending the active compounds with conventional ~093~

dispersible liquid diluent carriers and/or dispersible solid carriers optionally wi~h the use of carrier vehicle assis~ants, e.g., conven~ional sur-~ace-active agents, including emulsifying agents and/or dispersing agen.s, wllereby, for examp~e, in ~e case where water is used as diluen~, organic solvents may ~e added as auxiliary solvents. The following may be chiefly considered for use as conventional carrier vehicles for this purpose:
aerosol propellants which are gaseous at normal tempera.ures an~ pressures, such as halogenated hydrocarbons (dichlorodi-fluoromethane or trichlorofluoromethane) as well as butane, propane, nitrogen and carbon dioxide; inert dispersible liquid diluent carriers, including inert organic solvents, such as a.omatic hydrocarbons (e.g. benzene, toluene, xylene, alkyl naphthalenes, etc), halogenated, especially chlorinated, aromatic hydrocaîbons (e.g. chlorobenzenes, e~c.), cycloalkanes, (e.g. cyclohexane, etc.), paraffins (e.g. petroleum or min-eral oil fractions), chlorinated aliphatic hydrocarbons (e.g.
methylene chloride, chloroe~hylenes, etc.), alcohols (e.g.
methanol, ethanol, propanol, butanol, glycol, etc.), as well as ethers and es~ers thereo~ (e.g. glycol monomethyl ether, etc.), amines (e.gO ethanolamine, etc.~, amides (e.g. dimethyl formamide, etc.), sulfoxides (e.g. dimethyl sulfoxide, etc.), acetonitrile, ketones (e.g. acetone, methyl ethyl ketone, methyl isobutyl ke~one, cyclohexanone, etc.), and~or water;
as solid carriers, ground natural minerals, such as kaolins, clays, talc, chalk, quartz, attapulgite, mon~morillonite or diatomaceous earth, and ground synthetic minerals, such as highly-disperse~ 8ilicic acid, alumina and silicates; as solid carriers ~or grsnules; crushed and fractio~ated natural ~ o9c~
rocks such as calcite, marble, pumice, sepiolite and dolomite, as well as syn~hetic granules o inorganic and organic meals 9 and granules of organic ma~erial such as s~wdust, coconut shells, maize cobs and tobacco s~alks; whereas ~he followi~g may be chiefly considered for use as conventional carrier assistants, e.g. surface-active agents, for this purpose:
emulsifying agents, such as non-ionic and/or anionic emul-sifying agents (e.g. polyethylene oxide esters of ~at~y acids, polyethylene oxide ethers of aLty alcohols, alkyl sulfates, alkyl sulfonates, aryl sulfonates, albumin hydrolyzates, etc., and especially alkyl arylpolyglycol ethers, magnesium stearate, sodium oleate, etc.); and/or dispersing agents, such as lignin, sulfite waste liquors, methyl cellulsse, etc.
Adhesives such as carboxymethylcellulose and natural and synthetic polymers in the form o~ powders, granules or latices, such as gum arabic, polyvinyl alcohol and polyvinyl acetate, can be used in the formulations.
It is possible to use colorants such as inorganic pig-ments, for example iron oxide, titanium oxide and Prussian Blue, and organic dyestufs, such as alizarin dyestuffs, azo dyestuffs and metal phthalocyanine dyestufs, and trace nutrien~s such as 8alt9 of iron, manganese, boron, copper, cobalt, molybdenum and zinc.
Such ac~ive compounds may be employed alone or in the ~orm of mixtures with one ano~her and/or with such solid and/or liquid dispersible carrier vehicles and/or with other known compa~ible active agents, especially other plant protection agents, such as other in6ecticides, scaricide3, fungicides, bactericides, rodenticides and ~ertilizers, i desired, or in 0~

the form of particular dosage preparations for specific application made therefrom, such as solutions, emulsions, suspensions, powders, pastes, and granules which are thus ready for use.
As concerns commereially marketed preparations, these generally contemplate carrier composition mixtures in which the active compound is present in an amount substantially between about 0.1-95% by weight, and preferably 0.5-90% by weight, of the mixture, whereas carrier composition mixtures suitable for direct application or field application generally contemplate those in which the active compound is present in an amount substantially between 0.0000001-100, preferably 0.01-10%, by weight of the mixture Thus, the present invention con~emplates overall compositions which comprise mixtures of a conventional dispersible carrier such as ~1) a dispersible inert finely divided carrier solid, and/or ~2) a dispersible carrier liquid such as an inert organic solvent and/or water, preferably including a surface-active effective amount of a carrier vehicle assistant, e.g. a surface-active agent, such as an emulsiying agent and/or a dis-persing agent, and an amount of the active compound which is effective for the purpose in question and which is generally between about 0.0001-95%, and preferably 0.01-95%, by weight of the mixture.
The amount of actlve compound used can vary within a fairly wide range. It depends essentlally on the nature of the desired effect. In general, the amounts used are from Q.l to 20kg of active compound per hectare, preferably from Q.2 to lS kg/~a.

~O~

The active compounds according to the invention, as such or in their formulations, can be combined with otller herbicidal active compound~ to boost and supplement their spectrum Or action, depending on the intended use;
for this purpose, finished formulations or tank mixing may be employed.
Particularly preferred possible mixtures of the active compounds according to the invention are those with 3-(3,4-dichlorophenyl)-l,l-dimethyl-urea, 3-(3-trifluoromethyl-phenyl)-l,l-dimethylurea, 3-[3-(1,1,2,2-tetrafluoroetho~y~-phenyl]-l,l-dimethylurea, 2-methylthio-4,~-bis-ethyla~iro-1,3,5-triazine, 3-(3,4-dichlorophenyl)-1-methoxy-1-meth~l-urea, 2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolin~-3,5-dione, 2-ethylthio-4, 6-(isopropylamino)-1,3,5-triazine and 3-(3-chloro-4-trifluoromethoxyphenyl)-1,1-dimethylurea.
The active compounds according to the invention can be present in the formulations as mixtures with other active compounds, such as ~ungicides, in~ecticides and acaricides The active compounds can be used as such~ as their rormulations or as the use forms prepared therefro~, such as ready-to-use ~olutions, emulsions, suspensions, powders, pastes and granules. They may be used in the custamary manner, ror example by spraying, atomising, dusting, scatter-ing and watering.
Preferably, they are used in accordance with the pre-emergence process, i.e., they ~re applied to weed habitat ~efore its emergence.
The amount Or active compound used can vary within a fairly wide range. It depends essentially on the nature Or the desired efrect. In general, the amount~ used are rrom 0.1 to 20 kg o~ active compound per hectare D pre-ferably rrom 0.2 to 15 kg/ha.

~.093~,t~3 The present invention also provides a herbicidal composition containing as active ingredient a compound of the present invention in admixture with a solid or lique-ried gaseous diluent or carrier or in admixture with a liquid diluent or carrier containing a ~urface-active a~ent.
The present invention also provides a method of com-bating weeds which comprises applying to the weeds , or to a habitat thereor, a compound of the present invention alone or in the form of a composition containing as active ingredient a compound of the present invention in admixture with a diluent or carrier.
The present invention rurther provides crops protected froM damage by weeds by being grown in areas in which im-mediately prior to and/or during the time Or the growing a compound Or the present invention was applied alone or in acmixture with a diluent or carrier.
It will be seen that the usual method~ o~ providing harvested crop may be improved by the present invention.
The herbicidal activity o~ the compounds Or this invention is illustrated by the rollowing biotest Examples.
In these Examples, the compounds according to the present invention are each identi~ied by the number (given in brackets) Or the corresponding preparative Example, which will be ~ound later in this ~pecification.
The known comparison compounds are identified as ~ollows:

_ CF3 (A) = H3C-Sj/ ~-NH-S02-CH3 (known) 3 (B) - H3C-S0 ~ H-S02-CH3 (known) ( ) H3 2 ~ -NH-S02-CH3 (known) 10~30~

E~æ~
Pre-emergence test Solvent: 5 parts by weight of acetone Fmulsifier: 1 part by weight Or alkylaryl polyglycol ether To produce a suitable preparation o~ active compound, 1 part by weight of active compound was mixed with the stated amount o~ solvent, the stated amount Or emulsifier was added and the concentrate was diluted with water to the desired concentration.
Seeds of the test plants were sown in normal soil and, after 24 hours, watered with the preparation Or the active compound. It was expedient to keep constant the amount of water per unit area. The concentration of the active compound in the preparation was Or no importance, only the amount Or active compound applied per unit area being decisive. After three weeks, the degree of damage to the plants was determined in % damage in comparison to the development of the untreated control. The figures denoted:
0% = no action (like untreated control) 100% ~ total destruction The active compounds, the amounts appl;ed and the results can be ~een ~rom the table which follows:

~0~093 ~1 ~ ~ ~ ~ .

~1~1 o o o o o o o o o o o o 1 ~ I ~o ~o o o o o oo ~
o o o o o o o o o o o o o o~ oo oo oo oo o~ ~ooo .~c, ~1 ~1 o oo ~ ~D 00 0 ~J
O O O O O O O O O O O O
o o o o o o ~o ~ ~ ~ oo , ~ ~ ~ ~ . . ~
'C U~ ~
~ a) cd _l ~ o~
o o o o o o o o o o o o E-' h . ~1 ~n oo ~t ~ ~ ~
~d .~ g g g o o g o o oo ~o oo ~ 8 ~
o o~

~ o ~ ~
'c o ~

~0~30~3 Preparative Ex~mples Example 1 ClCH -SO NH~ SCH3 ~1) 31.6 g ~0.153 mol) of 2-trifluorom0thyl-4-methylthio-aniline were dissolved in 100 ml of pyridine and 56.6 g ~o.38 mol) of chloromethanesul-phonyl chloride were added dropwise at 0C to 10C. The mixture was sub-sequently stirred for one hour at room temperature and the reaction so-lution was then introduced into dilute hydrochloric acid and extracted with methylene chloride. After drying the organic phase the solvent was stripped off. 50 g of a dark oil remained which essentially consisted of N,N-~bis-chloromethylsulphonyl)-2-trifluoromethyl-4-methylthio-aniline.
42 g of the oil were dissolved in 200 ml of methanol. 17 g ~0.3 mol) of potassium hydroxide were added to this solution and the mixture was then stirred for some hours at room temperature. After some time, a crystalline product began to separate out. This was dissolved in water and acidified with hydrochloric acid. 28 g ~90~ of theory) of chloro-methanesulphonic acid 2-trifluoromethyl-4-methylthio-anilide were hereby obtained in the form of a solid substance of melting point 98 - 99C.
Example 2 ClCH2-SO2-NH ~ S0-CH3 ~2) 10 g ~0.031 mol) of chloromethanesulphonic acid 2-10~30~.~

trifluoromethyl-4-methylthio-anilide were dissolved in 50 ml of glacial acetic acid and 3.4 g ~0.03 mol) of 30% strength hydrogen peroxide were added at 15C to 20C. The mixture was stirred for a further 6 hours at 15C to 20C, 100 ml of water were then added and the reaction mixture was extracted with mcthylene chloride. After drying the organic phase the solvent was stripped off. The slowly crystallising product ~hich thereby remained was recrystallised from an ethanol/petroleum ether mixture.
In this manner, 5 g C50% of theory~ of chloromethanesulphonic acid 2-trifluoromethyl-4-methylsulphinyl-anilide were obtained in the form of a solid substance of melting point 110 - 113C.
Example 3 ClCH2 S02-NH ~ S02-CH3 F3C ~3) 13 g ~0.041 mol) of chloromethanesulphonic acid 2-trifluoromethyl-

4-methylthlo-anilide were dissolved in 50 ml of glacial acetic acid and 18 ml C0.16 mol) of 30% strength hydrogen peroxide were added at 60C.
The temperature of the reaction mixture thereupon rose to the boiling point.
The mixture was heated under reflux for a further 2 hours and 50 ml of water were then added. On cooling, the reaction product separated out in the crystalline orm. In this manner, 13 g ~91% of theory) of chloro-methanesulphonic acid 2-trifluoromethyl-4-methylsulphonyl-anilide were obtained in the form of a solid substance of melting point 190 - 191C.

Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Chloromethanesulphonic acid 2-trifluoromethyl-anilides of the general formula (I) in which ? represents 0, 1 or 2.

2. A chloromethanesulphonic acid 2-trifluoromethyl-anilide accord-ing to claim 1 wherein ? represents 0.

3. A chloromethanesulphonic acid 2-trifluoromethyl-anilide accord-ing to claim 1 wherein ? represents 1.

4. A chloromethanesulphonic acid 2-trifluoromethyl-anilide accord-ing to claim 1 wherein ? represents 2.

5. A method of combating weeds which comprises applying to the weeds or their habitat a herbicidally effective amount of a compound of the formula (I) defined in claim 1.

6. A method according to claim 5 wherein said compound is applied to an area of cultivation at a rate of 0.1 to 20 kg per hectare.

7. A method according to claim 6 wherein said compound is applied at a rate of 0.2 to 15 kg per hectare.

8. A method according to claim 5 wherein said compound is applied to a standing crop of cotton.

9. A method according to claim 6, 7 or 8 wherein the compound of formula (I) is one wherein n is 0.

10. A method according to claim 6, 7 or 8 wherein the compound of formula (I) is one wherein n is 1.

11. A method according to claim 6, 7 or 8 wherein the compound of formula (I) is one wherein n is 2.