STABILISED HERBICIDE COMPOSITION BASED ON META-BISCARBAMATES

Abstract: A stabilised herbicide composition containing one or more compounds of formula: (wherein R₁ can be alkyl, cycloalkyl or substituted alkyl; R₂ can be hydrogen, alkyl or phenyl, or can form a heterocyclic ring jointly with R₁ and with the nitrogen atom; and R₃ is an alkyl, alkenyl or alkynyl) together with a stabilizer, possibly also having a surface-active effect, as well as with other possible coadjuvant and inert substances.

Description: "STABILISED HERBICIDE COMPOSITION BASED ON META-BISCARBAMATES" ==**== This invention relates to a stabilised herbicide composition based on meta-biscarbamates. It is known that herbicide compositions containing a compound of formula: EMI1.1 (wherein R1 can be alkyl, cycloalkyl or alkyl substituted by halogen and/or alkyl and/or trifluoromethyl3 R2 can be hydrogen, alkyl or phenyl, or R1 and R2 jointly with the nitrogen atom can form a heterocyclic ring which may contain additional nitrogen or oxygen atoms: R3 is an alkyl, alkenyl, alkynyl, which may be substituted by hydrogen, alkoxy or dialkylamino) possess excellent herbicide action on sugar beet and other crops, if formulated with suitable adjuvants and interts. However, it is also known that the aforesaid compounds possess limited stability with time if prepared in common emulsifiable liquid herbicide compositions based on organic solvents, and which contain adjuvants and inerts having no stabilising effect. U.S. patent No. 3,898,075 describes the possibility of stabilising compounds of formula (A) in emulsifiable liquid herbicide compositions based on organic solvents, by adding a stabilising compound chosen from dicarboxylic aliphatic acids, hydrocarboxylic aliphatic acids, nitro-substituted monocarboxylic aromatic acids, dicarboxylic aromatic acids, sulphonated aliphatic acids, and sulphonated aromatic acids. In addition to claiming these stabilisers, the aforesaid U.S. patent describes the already known addition of common adjuvants and inerts commonly used by the expert in this field for preparing emulsi friable liquid composition suitable for use as plant protection products. Specifically, stated suitable inerts are solvents based on aromatic hydrocarbons, cyclohexanone, isophorone, methylhexahydronaphthalene, dibutylphthalate, tetrahydronaphthalene, dimethylsulphoxide and dimethylformamide, and stated suitable surfactants are polyethoxylated amines, alcohols, acids and alkylphenols, and salts of alkylbenzene and naphthalenesulphonic acids. With the present invention, it has been unexpectedly found that compounds of formula: EMI2.1 (wherein R1 can be alkyl, cycloalkyl or alkyl subsituted by halogen and/or alkyl and/or trifluoromethyl; R2 can be hydrogen, alkyl or phenyl, or R1 and R2 jointly with the nitrogen atom can form a heterocyclic ring which may contain further nitrogen or oxygen atoms R3 is an alkyl, alkenyl, alkynyl, possible substitued by halogen, alkoxy or dialkylamino) can be formulated either as organic solvent-based emulsifiable liquids or as fluid aqueous suspensions, and that such formulations may be stabilized with one or more of the following compounds: I) phosphoric and/or suphuric acids, totally or partially esterified with aliphatic alcohols or with phenols or with alkyl phenols, even tually polyethoxylated or polypropoxylated or partially neutra lized. II) monocarboxylic aromatic organic acids, which may be substituted3 III) inorganic acids and their salts, for use only in formulations in the form of fluid aqueous suspensions3 IV) water soluble aliphatic or aromatic organic acids, which may be substituted, for exclusive use in fluid aqueous suspensions. With regard to the present invention, the most interesting compounds of formula (A) are: 3-methoxycarbonyl-ami nophenyl-N-( 3-meythylphenyl) carbamate (Phenmedipham); 3-ethoxycarbonyl-aminophenyl-N-(3-methylphenyl) carbamate (Phen medipham ethyl)3 3-ethoxycarbonyl-aminophenyl-N-phenylcarbamate (Desmedipham)3 3-(N,N-dimethylureido)-NT-mehtyl-N-phenylcarbamate; 3-(methoxyzarbonylamino)-phenyl-N-methyl-N-phenylcarbamates 3-(methoxycarbonylaminophenyl )-N-( 3-methylbutyl-2) carbamate. Example of the aforesaid stabilisers for the compound of formula (A) as I II III IV which are usable either in organic solvent-based emulsifiable liquid formulations or in fluid aqueous suspensions are as follows, divided into the groups defined heretofore: I) phosphoric esters or phosphates of polyethoxylated allylphenols of polyethoxy lated tristyryl and distyrylphenol phosphate type (available commercially for example under the names SOPROPHOR or SOPRAL 3D 33 of Messrs. SOPROSOIE of Rochetaillee, France or under the name SOITEM 8 FL of Messrs. SOITEM, Milan, Italy). phosphoric esters of non-polyethoxylated synthetic alcohols (for example SOPROPHOR MB of the aforesaid Messrs. SOPROSOIE); sulphonic esters or sulphates of polyethoxylated arylphenols, partially neutralised with ammonia (for example SOITEM FS of Messrs. SOITEM, or PREPARATION 1O-D-163 of Messrs. SOPROSOIE) phosphoric esters of polyethoxylated nonyl phenol (as, for example, the market compounds with the trade marks GEK1NTOL PR H-4A and GERENOL PR H-4B of the firm Geronazzo, Milan, Italy)3 sulphuric esters of linear alcohols C8-C10 neutralized as isopropylamine salt (as, for example, the compound sold with the trade mark SOITEM AS/9 of the firm SOITEM, Milan, Italy). II) benzoic acid, ortho-chlorobenzoic acid, para-aminobenzoic acid3 III) ortho-meta and hypophosphoric acid3 sulphuric acid, nitric acid, hypochloric, perchloric and hydrochloric acid3 sulphates, nitrates and ammonium phosphates; to be used as stabilizers only for fluid aqueous suspensions of meta-biscarbamates5 IV) formic, acetic, monochloroacetic, propionic, citric, tartaric, oxalic, malic, toluenesulphonic, benzosulphonic, methanesulphonic and ethanesulphonic acids also to be used only as stabilizers for fluid aqueous suspensions. With respect to the known art, the interest of the present invention is even greater when considering that various substances among those cited hereabove able to exhibit a stabilising effect also possess the property of acting as surfactants, ie as emulsifying or suspending agents, in herbicide formulations of either emulsifiable liquid or fluid aqueous suspension form, based on compounds of formula (A), with obvious saving in adjuvants and greater composition economy. Moreover, all the stabilisers according to the invention exhibit their action in relatively small. doses, for the most part economical. In this respect, said stabilisers can be added to the composition according to the invention in a percentage varying from 0.005% to a theoretical maximum of 50% by weight, according to the type of formulation and the concentration of the compounds of formula (A). In addition to the stabilisers with possible surfactant effect according to the invention, other surfactants, suspending agents or emulsifying agents can be added to formulations comprising compounds of formula (A), as necessary for optimising the hydrophilic/lipophi lic balance of the composition in accordance with the methods well known to the expert in this field (for example calcium akylarylsulphonate, polyethoxylated fatty acids, polyethoxylated alkylarylphenols and others, described in the publication Mc Cutcheon's - Detergent L Emulsifiers - 1982 Annual - International Edition, Glen Rock (N.J.) U.S.A. Other active antiparasite or adjuvant substances can also be added to the formulations according to the invention, in particular other herbicides, such as chloridazon, metamitron, ethofumesate, lenacil, cycloate, diallate, triallate, butachlor, metolachlor, trimexachlor and others. Of particular interest is the fact that the stabilisers according to the present invention can be used not only in organic solvent-based emulsifiable liquid formulations, but also, contrary to the known art, in aqueous suspension formulations in the form of fluid pastes (flowables), which can contain a higher concentration of active herbicide substances than is generally possible with emulsifiable liquid solutions of compounds of formula (A). In the case of organic solvent-based liquid formulations which are emulsifiable in water, the following composition can be used by way of example: 5-50 (preferably 10-35%) of active substances of formula (A); 0.1-30 (preferably 0.5-20%) of stabiliser, which may also possess emulsifying action, possibly together with a further surfactant (emulsifier) not possessing stabilising action; Remainder to 100% of solvent, together with other emulsifier if necessary. The solvents used can be isophoronc, cyclohexanone, aromatic hydrocarbons, dimethylsulphoxid, dimethylformamide, N-methylpyrrolidonc and others. According to one particular aspect of the present invention, it is also possible to prepare herbicide compositons containing active substances of formula (A) as aqueous suspensions in fluid paste (flowables). An improved type of paste formulation is prepared by micronisation in sand (or pearl) mills so as to attain an extremely fine active substance particle size, which is nearly totally less than 10 microns and having a high percentage of particles less than 2.5 microns. Such fluid aqueous suspension formulations can for example comprise the following usual components: 16-60% (preferably 40-55%) of active substances of formula (A)3 0.005-20% (preferably 0.1-10%) of stabiliser possibly with dispersing action3 and if necessary in mixture with other dispersants3 3-15% (preferably 4-8%) of an alcohol or glycol of antifreeze action (eg. Methyl alcohol or ethylene glycol)3 0.05-0.6% (preferably 0.1-0.4%) of a hetero or homo-polysaccharide thickening agent, possibly salified3 0.02-0.2% (preferably 0.04-0.08%) of an antifoaming compound (such as a silicone compound). 0.01-0.2 (preferably 0.02-0.1%) of an antibacterial or antifungal compound (such as a derivative of para-oxybenzoic acid or formaldehyde)3 remainder to 100%: water. Water base fluid pastes can also be prepared by emulsifying in water the active principle dissolved in a suitable solvent, with addition of suitable emulsifying and suspending agents as well as a stabilizer selected among those indicated by the present invention. The following can be listed as components of such type fluid pastes based on a water concentrated emulsion: - 5-35 (preferably 8-17) of active substances of formula (A); - 10-50% (preferably 15-30%) of suitable organic solvents - 0.005-20 (preferably 0.1-10%) of stabilizer according to the invention, possibly also with emulsifying function; - 2-20% (preferably 5-15%) of suitable emulsifiers, which can be mixed with stabilizers possibly with function of emulsifiers - o.o-o.6% (preferably 0.1-0.4%) of a thickening agent of the type of hydrophile polymer3 - 0.01-0.2% (preferably 0.02-0.1%) of a bactericide and fungicide com- pound; - remainder to 100%: water. The composition according to the invention is particularly suitaable for use in the selective de-weeding of, agricultural or horicultural crops (such as sugar beet, fodder beet, beetroot, wheat, barley, corn, soya, groundnuts, citton, beans, peas, spinach, strawberries) mainly in treatment after emergence, (and in the case of certain compounds also in treatment before emergence or before sowing), by spraying dilute aqueous emulsions or suspensions containing from 0.15 to 3 kg/ha of active substance. The following examples are useful for better illustrating the invention, but do not limit its possible applications. EXAMPLE 1 The following substances are fed into a vessel fitted with a liquid stirrer, and are kept constantly mixed: 1st Group of Formulations Formula I Formula II 3-methoxycarbonyl-aminophenyl-N-(3- methylphenyl) carbamate of 97% purity 17.2 kg 17.2 kg SOITEM 8 FL (1) 8.0 kg Calcium dodecylbenzenesulphonate 2.0 kg SOITEM FS (1) - 14.0 kg Cyclohexanone - 15.0 kg Isophorone 72.8 kg 53.8 kg Total 100 kg 100 kg Formula III Formula IV -N-(3-methylphenyl) carbamate with 97% purity 17.2 kg 17.2 kg SOITEM AS/9 (1) 8.0 kg GERONOL PR H-4A (2) - 7.0 kg GERONOL PR H-4B (2) - 2.0 kg SOITEM 101 (1) 5.0 kg SOITEM 999 (1) 2.0 kg Cyclohexanone 10.0 kg Isophorone 57.8 kg 73.8 kg Total 100.0 kg 100.0 kg Formula V Formula VI 3-methoxycarbonyl-amino-phenyl N-(3-methylphenyl) carbamate with 97% purity 17.2 kg 17.2 kg SOPRAL FL (3) 8.0 kg SOITEM 8 FLN (1) - 9.0 kg SOPRAL 70 (3) 2.0 kg 1.0 kg 2-hydroxybenzoic acid 1.5 kg Benzoic acid - 2.0 kg I sophorone 71.3 kg Cyclohexanone - 70.8 kg Total 100.0 kg 100.0 kg Various liquid, water emulsifiable, stabilized formulations are thereby obtained, to be used as herbicides. 1) Messrs. SOITEM Milan (Italy) 2) Messrs. GERONAZZO Milan (Italy) 3) Messrs. SOPROSOIE Rochetaillee (France) EXAMPLE 2 The following products are mixed together under stirring in a paste mixer: Formula VII VIII IX X 3-methoxy-carbonyl-aminophenyl N-(3-methylphenyl) carbamate of 97% purity in poweder form 515 515 344 500 kg SOPROPHOR 3D 33 (1) 25 - - - kg SOITEM FS (2) - 25 - - kg GERONOL TZA (3) - - 25 - kg SOPRAL FL (1) - - - 25 kg SOITEM 09 AF - 50 - - kg Hydrochloric acid - - 0.2 - kg Citric acid - - - 1 kg Ethylene glycol 60 60 60 60 kg Alkylpolysiloxane 1 1 1 1 kg Heteropolysaccharide, sodium salt 3 3 3 3 ks Formaldehyde 40% 1 1 1 1 kg Water to make up to 1000 1000 1000 1000 litres After careful mixing, the entire mixture is ground in a pearl mill to obtain a stailised fluid suspension in water with very fine solid particles (eg. 99% less than 10 microns and 60% less than 2.5 microns) particularly suitable for use as a herbicides. 1) Messrs. SOPROSOIE, France 2) Messrs. SOITEM, Italy 3) Messrs. GERONAZZO, Milan, Italy EXAMPLE 3 The chemical sta.bility of the active substance is observed at various temperature levels (200C and 540C) for various lengths of time (1 month and 3 months) in the case of certain organic solvent-based emulsifiable liquid fomulations according to the invention comprising stabilisers as indicated in Example 1, compared with an emulsifiable liquid formulation without stabilisers and having the following composition: 3-methoxy-carbonyl-aminophenyl N-(3-mehylphenyl) carbamate of 97% purity 17.2 kg SOITEM 101 1.0 kg SOITEM 990 7.0 kg I sophorone 74.8 kg Total 100.0 kg The results are shown in Table 1, from which it can be seen that the addition of the stabiliser according to the invention prevents rapid decomposition of the active substances, even if the emulsifiable liquid formulation is kept at elevated temperature for a long period. TABLE 1 Stability of the active substance 3-methoxycarbonyl-aminophenyl N-(3-methylphenyl)carbamate in emulsifiable liquid compositions, with and without stabilisers according to the invention. % decomposition of active substance after T 1 month 3 months Composition with stabiliser 200C 0 0 Formula I (Example 1) 540C O 2 Composition with stabiliser 200C O 0 Formula II (Example 1) 540C O 3 Composition with stabiliser 200C 0 0 Formula III (Example I) 54 C o 3 Composition with stabiliser 200C 0 0 Formula IV (Fxample 1) 54 C O o 1 Composition with stabiliser 200C 0 0 Formula V (Example 1) 540C o 3 Composition without stabiliser 200C 3 10 Formula of Example 3 540C 30 60 F-YAt1PLE 4 The stability of a composition formulated as an aqueous fluid suspension and prepared with a stabiliser according to the invention (as indicated in Example 2) is compared with an analogous composition without stabiliser, and having the following composition: 3-methoxycarbonyl-aminophenyl-N-(3-methylphenyl) carbamate of 97 purity 515 kg GERONOL TZA 25 kg Ethylene glycol 60 kg Alkylpolysiloxane 1 1 kg Heteropolysaccharide, sodium salt 3 kg Formaldehyde 40% 1 kg Water to make up to 1000 litres The results given in Table 2 clearly indicate that the composition comprising the stabiliser according to the invention possesses excellent stability of its active substance, which however decomposes rapidly in the composition without stabiliser. TABLE 2 Stability of the active substance 3-methoxy-carbonyl-aminophenyl- N-(3-methylphenyl) carbamate in compositions formulated as an aqueous fluid suspension with and without stabiliser according to the invention. % decomposition of active substance after T 1 month 3 months Composition with stabiliser 200C 0 0 Formula VIII (Example 2) 540c O 4 Composition with stabiliser 200C 0 0 Formula VII (Example 2) ¯ ¯ 54 C O 3 Composition with stabiliser 200C 0 0 Formula X (Exmaple 2) 540C O 2 Composition with stabiliser 200C 0 0 Formula IX (Example 2) 540c n 3 Composition without stabiliser 200C 5 15 Formula of Example 4 54 C 45 70

Claims: CLAIMS 1) A stabilised herbicide composition formulated as an organic solvent-based emulsifiable liquid or a fluid aqueous suspension or emulsion containing one or more compounds of formula: EMI13.1 (wherein R1 can be alkyl, cycloalkyl, or alkyl substituted by halogen and/or alkyl and/or trifluoromethylj R2 can ie hydrogen, alkyl or phenyl, or R1 and R2 jointly with the nitrogen atom can form a heterocyclic ring, which may contain further nitrogen or oxygen atoms; R3 is an alkyl, alkenyl, alkynyl, which may be substituted by halogen, alkyoxy, or dialkylamino) together with one or more of the following stabilisers: : I) phosphoric and/or sulphuric acids, totally or partially esterified with aliphatic alcohols or with phenols or with alkyl phenols, eventually polyethoxylated or polypropoxylated or partially neutralized; II) monocarboxylic aromatic organic acids, which may be substituted3 III) inorganic acids and their salts, for use only in formulations in the form of fluid aqueous suspensions3 IV) water soluble aliphatic or aromatic organic acids, which may be substituted, for exclusive use in fluid aqueous suspensions. 2) A composition as claimed in claim 1, wherein the compound of formula (A) is 3-ethoxyzarbonyl-amino-phenyl-N-(3-methylphenyl) carba mate. 3) A composition as claimed in claim 1, wherein the compound of formula (A) is 3-ethoxycarbonyl -amino-phenyl-N-( 3-methylphenyl) carbamate. 4) A composition as claimed in claim 1, wherein the compound of formula (A) is 3-ethoxycarbonyl-amino-phenyl-N-phenylcarbamate. 5) A composition as claimed in claims 1 to 4, wherein the stabilisers of formula (II) also act as surfactants, emulsifiers and/or suspending agents. 6) Composition as in claim 1 to 4, wherein the stabiliser is benzoic acid. 7) Composition as in claim 1 to 4, wherein the stabilizer is a substituted benzoic acid. 8) Composition as claimed in claims 1 to 7, wherein the stabilisers concentration is between 0.005% and 50% by weight. 9) A process for preparing a composition as claimed in claims 1 to 8 in the form of an organic solvent-based liquid emulsifiable in water by mixing the active substance with emulsifying and stabilizing solvents. 10) A process for preparing a composition as claimed in claims 1 to 8 in the form of a fluid aqueous suspension by mixing the active substance and with the coadjuvants and subsequent griding of the solid active substance with a ball mill. 11) Process for preparing a composition as in 1 to 8 in the form of a fluid aqueous emulsion, by mixing the active substance with emulsifying, coadjuvant and stabilizing solvents, obtaining a concentrated aqueous emulsion by mixing with water. 12) A method of application of a composition as claimed in claims 1 to 6 for the selective de-weeding of agricultural and horticultural crops in treatments after emergence, before emergence or before sowing wherein between 0.15 kg/ha and 3 kgZha of active substance are distributed.

Inventors: CIOCCA, BALDO, EPIS, GINO, FORMIGONI, ATTILIO
Applicants: S.I.P.C.A.M. S.P.A. SOCIETA ITALIANA PRODOTTI CHIMICI E PER L'AGRICOLTURA MILANO
Application year: 1983
Main classification: A01N25
IPC codes: A01N47, A01N25