AGROCHEMICAL ADJUVANT SURFACTANTS

Abstract: Surfactant adjuvant compounds of formula (I) where R<1>, R<2>, R<3>, R<4>, and R<5> have defined meanings can be used with particular effect with glyphosate type herbicides to kill weed species that are recognised as particularly difficult to kill. Examples of such weeds are broad leaved (dicotyledon) weed such as Chenopodium album, Solanum nigrum, Lactuca saligna, Amaranthus retroflexus and Erigeron canadensis (annuals) and Cirsum arvense (perennial) and similar related weeds from these genera and perennial monocotyledon such as Lolium perenne, Convolvulus arvensis and, especially, Agropyron repens and similar related weeds from these genera.

Description: AGROCHEMICAL ADJUVANT SURFACTANTS This invention relates to the use of certain surfactants as adjuvants in agrochemical formulations, particularly herbicidal compositions using gylphosate and similar herbicides Our PCT Application PCT/GB 95/02785 (published as WO96/16930) relates to a class of surfactants of the general formula [formula (I) in PCT/GB 95/02785] (R 1 H) C CO NR 3 R 4 I (R 2 H) C CO R 5 1 2 3 4 5 1 2 where R , R R , R and R have defined meanings (generally one of R and R is an alkyl or 3 4 alkenyl group and the other is hydrogen, -NR R is a polyhydroxylhydrocarbylamino group, 5 3 4 particularly a glucamino group, and R is an -NR R group, a different ammo group or a polyoxyaikylene group which may include a substituent at the end of the chain) The application describes various uses for these compounds, including as laundry detergents, pigment dispersant surfactants and as adjuvant surfactants in agrochemical formulations including as adjuvants in herbicidal compositions based on glyphosate type herbicides. In current practice, using glyphosate type herbicides, the application rate to ensure effectiveness against difficult to kill weeds, particularly broad leaved weeds, is typically about 30 to 50% higher than would be needed to kill general weeds It would be very desirable to have an adjuvant that would make such herbicides as effective against the difficult to kill weeds as they now are against the relatively easier to kill weeds The present invention is based on our discovery that the surfactants of our earlier PCT case can perform as adjuvants to give enhanced effectiveness of glyphosate type herbicides against weeds, particularly broad leaved and perennial weeds, that are generally relatively more difficult 5 to kill In particular, this discovery applies to compounds of the where R is a (gluc)amιno group or a polyoxyaikylene group, corresponding to compounds of the sub-formulae (1a) and (1b) of Application No PCT/GB 95/02785 The present invention accordingly provides a method of killing weeds which are difficult to kill, which comprises applying to the weeds a herbicidal composition including as active herbicide a glyphosate type herbicide compound and as adjuvant a compound of the formula (I) (R 1 H) C CO NR 3 R 4 (I) I (R 2 H) C CO R 5 where 1 2 one of R and R in the succinic acid moiety is C 6 to C 2 2 alkenyl or alkyl and the other is hydrogen, R 4 is hydrogen, C 1 to C 22 hydrocarbyl, particularly C 1 to C 20 alkyl, R 5 is a group -NR R where R 3 and R 4 are independently as defined above, or R is a group -O (AO) n R where AO is an alkylene oxide, particularly an ethylene oxide, residue, n is 1 to 200, and R is hydrogen, or C 1 to C 22 hydrocarbyl, particularly C 1 to C 6 alkyl The invention is specifically applicable to the use of compounds ot the formula (la) or (lb) (R 1 H) C CO NR 3 R 4 (la) (R 2 H) C CO.NR 3 R 4 or (R 1 H) C CO NR 3 R 4 (lb) I (R 2 H) C CO O (AO) n R 6 where R 1 , R 2 , R , R 4 and R are as defined above A particularly advantageous sub-class of the compounds of the formula (1 a) above, which have good compatibility with glyphosate type herbicides in aqueous formulation, are compounds of the formula (la 1 ) (R 11 H) C CO NR 13 R 14 (la') (R 12 H) C CO NR 13 R 14 where 11 12 one of R and R in the succinic acid moiety is C 6 to C 12 alkenyl or alkyl and the other is hydrogen, 13 each group R is a glycosyl group, particularly glucosyl group, and each group R is hydrogen, or a C 1 to C 4 alkyl group The surfactant adjuvant compounds used in this invention can be made by the methods descnbed in PCT/GB 95/02785 When made by such methods, compounds used in this invention are, as described in that application, typically mixtures of isomers corresponding to the two senses of anhydride ring opening during synthesis The invention particularly includes a method of killing weeds which are difficult to kill, which comprises applying to the weeds a herbicidal composition including as active herbicide a glyphosate type herbicide compound and as adjuvant a compound of the formula (la), particularly formula (la'), and/or (lb) as defined above Specifically the invention includes a method of killing weeds which are difficult to kill, which comprises applying to the weeds a herbicidal composition • ncluding as active herbicide a glyphosate amine salt, particularly glyphosate fsopropylamino salt (Λ/-phosphonomethylglycιne /sopropylamine salt), and as adjuvant a compound of the formula (la), particularly formula (la'), and/or (lb) as defined above In referring to weeds as being difficult to kill we mean that on application of glyphosate type herbicides, the weeds either require a significantly higher application of herbicide to kill them than the generality of weeds or that they are not killed rapidly In particular this applies to broad leaved dicotyledon weeds (annuals and perennials) and to grass (generally monocotyledon) perennial weeds Examples include the broad leaved (dicotyledon) weeds of the species- Chenopodium album, Solarium nigrum, Lactuca saligna, Amaranthus retroflexus and Erigeron canadensis (annuals) and Cirsum arvense (perennial) and similar related weeds from these genera and perennial monocotyledon weeds of the species. Lolium perenne, Convolvulus arvensis and Agropyron repens and similar related weeds from these genera Among the grass weeds, Agropyron repens is particularly recognised as being difficult to kill The term glyphosate type herbicide refers to Λ/-phosphonylrrιethylglycιne herbicides particularly herbicide compounds of the formula MO C(O) CH 2 N(2) CH 2 . P(0) (OM) 2 where M, and Z (as Z 11 ) are as defined in PCT Application No PCT/GB 95/02785 In particular such compounds where Z is hydrogen are very desirable for use as herbicides and thus the compound HO.C(0).CH 2 NH CH 2 .P(0).(0H) 2 and its salts with agriculturally acceptable salt-forming species are especially useful in the invention Suitable salt-forming species include alkali metal, particularly sodium, potassium, or rubidium, alkaline earth metal particularly magnesium or calcium, ammonium, primary, secondary, tertiary or quaternary aliphatic ammonium, preferably where the total number of carbon atoms is not more than about twelve, trialkylsulphonium, preferably where the total number of carbon atoms is not more than about six, such as tπmethylsulphonium, ethyl dimethylsulphonium and propyl dimethylsulphonium In especially useful compounds, each M is hydrogen, alkali metal, ammonium, monoalkyi ammonium or trialkylsulphonium moiety. In the most preferred compounds, one M is an alkali metal, ammonium, monoalkyi ammonium, or trialkylsulphonium, and two are hydrogen Examples of especially preferred compounds include isopropylamine Λ/-phosphonomethylglycιne, tπmethylsulphonium Λ/-phosphonomethylglycιne and sodium sesquι-Λ/-phosphonomethyl-glycιne Combinations of two or more such compounds can be used in the present invention The mechanism by which these surfactants are especially effective against difficult to kill weeds is not certain, but is seems that either the surfactant forms lamellar and/or liquid crystalline phases or structures in the coatings on the leaves of the weeds enhancing retention of the active component on the leaf surface, or the adjuvant enhances absorption of the active component into the leaves of the weed (the structures referred to above may assist in this), or the surfactant enhances translocation of the active herbicide within the weed after absorption Whatever the mechanism, the effect seems to be substantial and is seen, at equal rates of application of active herbicide in an increase in the speed of killing weeds, especially difficult to kill weeds and/or that weeds, especially difficult to kill weeds, are killed with lower application rates of the active herbicide than would otherwise be needed, in particular reducing effective application rates to those typical for effective control of weeds that are not difficult to kill In addition to enhanced effectiveness and/or speed of action, particularly in killing difficult to kill weeds, the adjuvants used in the present invention may also reduce the effect of seed spread from treated weeds, and/or provide improved rain fastness of the applied herbicides The invention is particularly applicable to the use of glyphosate itself (Λ/-phosphonomethy!glycιne /sopropylamine salt) as the surfactants used in the invention are especially effective with glyphosate Indeed, using glyphosate as the active herbicide with adjuvants used in this invention can give formulations which are more effective, particularly in their effectiveness at lower concentrations and/or in their speed of action, than otherwise similar formulations made using the closely related herbicide sulphosate, which has the same core acid active entity but as the dimethylsulphate salt As is noted above this use of glyphosate (Λ/-phosphonomethylglycιne /sopropylamine salt) forms a specific aspect of the invention The enhanced herbicidal effect arising from the use of compounds of the formula (I) is particularly noticeable against broad leaved (dicotyledon) weeds especially of the species Chenopodium album, Solanum nigrum, Lactuca saligna, Amaranthus retroflexus and Erigeron canadensis (annuals) and Cirsum arvense (perennial) and similar related weeds from these genera and perennial (generally monocotyledon) weeds of the species Lolium perenne, Convolvulus arvensis and Agropyron repens and similar related weeds from these genera Good and enhanced effects have also been observed against grass (monocotyledon) annual weeds for example of the species Sorghum halepense and similar related weeds indicating the broad spectrum activity of formulations including the adjuvants used in this invention Accordingly, the invention particularly includes a method of killing a weed selected from Chenopodium album, Solanum nigrum, Lactuca saligna Amaranthus retroflexus, Erigeron canadensis and Cirsum arvense and/or a weed selected from Lolium perenne, Convolvulus arvensis and Agropyron repens which comprises applying to the weeds a herbicidal composition including as active herbicide a glyphosate type herbicide compound, particularly Λ/-phosphonomethylglycιne /sopropylamine salt, and as adjuvant a compound of the formula (la) or (lb) above, specifically and in particular an adjuvant of the formula (la') above The amounts of the materials used will generally be within the broad ranges typically used in the art with similar materials However, as the compositions used in this invention can be more effective it may be possible to reduce the amount or concentration of the active herbicide as compared with conventional formulations Considered as proportions of spray compositions (so-called 'tank mixes') at current spray volume application rates of about 300 1 ha "1 the concentration of active herbicide will typically be from about 0 05 to about 3%, more usually from about 0 1 to about 0 5 and particularly about 0.2%, and the concentration of adjuvant will typically be from about 0 02 to about 2% more usually from about 0 2 to about 1 % and particularly about 0 1 % The weight ratio of active herbicide to adjuvant surfactant will typically be from about 1 5 to about 10 1 , more usually about 1 2 to about 4'1 and particularly about 2 1 Where low volume spraying methods are used, 5 the concentrations will typically be correspondingly higher, but the ratio of active herbicide to adjuvant will generally remain within the stated ratios Thus for low volume spraying at formulation application rates of 20 to 50 1 ha ' , the concentration of active herbicide will typically be from about 0 3 to about 30%, more usually from about 0 5 to about 15 and particularly about 5%, and the concentration of adjuvant will typically be from about 0 1 to about 15% more usually from 10 about 0 5 to about 10% and particularly about 7%, with ratios typically corresponding to the above ranges Expressed as amounts of the components applied to unit area of field, the active herbicide will typically be applied at a rate of about 300 to about 4000 g ha 1 , more usually about 750 to about 2000 g ha 1 , and particularly about 1000 to about 1500 g.ha 1 , and correspondingly, the amount of adjuvant surfactant applied will typically be from about 150 to about 4000 g ha 1 , more 15 usually about 500 to about 2000 g ha "1 The adjuvant surfactants, especially those of the formula (1 a'), used in this invention have good compatibility with glyphosate type herbicides, they can be formulated into herbicidal concentrates for dilution to tank mixes In such formulations, the active herbicide will typically be at a concentration of from about 5 to about 60%, more usually from about 10 to about 40% and the ?n adjuvant surfactant, particularly an adjuvant surfactant of the formula (1 a'), at a concentration of from about 3 to about 50%, more usually from about 5 to about 30%, by weight of the concentrate The adjuvants used in this invention can be incoφorated into aqueous herbicide formulations as such However, we have found that the use of accessories or co-solvents can usefully improve the solubility of the adjuvants as used with the glyphosate herbicides Suitable accessories and 25 co-solvents are generally water soluble and/or miscible organic solvents for the adjuvant surfactants and include glycols, such as ethylene glycol and particularly propylene glycol (so-called 'monopropylene glycol'), low molecular weight polyglycol ethers and their mono alkyl ethers such as di- and tπ-ethylene glycol, di- and tn-propylene glycol and their C, to C 4 mono alkyl ethers and dimethyl isosorbide When used the proportion of accessory or co-solvent will typically be from 30 about 10 to about 150%, more usually from about 25 to about 75% by weight of the adjuvant used The adjuvant surfactants used in this invention have relatively low toxicity and are readily biodegradable. In addition, in combination with the glyphosate type herbicide in aqueous formulation, the adjuvant surfactants are much less susceptible to foaming than the alkyl polyglycoside surfactants that have been suggested for use, particularly with sulfosate (N-phosphonomethyl glycine trimethylsulphonium salt). The following Examples illustrate the invention. All parts and percentages are by weight unless otherwise stated. Materials MPG mono-propylene glycol GAS technical grade N-phosphonomethyl glycine as the isopropylamine salt in aqueous solution (nominally 62% active salt) GSS technical grade N-phosphonomethyl glycine as the trimethylsulphonium salt in aqueous solution (nominally 52% active salt) ETA conventional ethoxylated tallow amine adjuvant (95+% active) APS alkyl polysaccharide adjuvant composition from ICI (about 75% APS) water the water used to make up the spray formulations used in the Examples had a standard hardness of 342 ppm. glucamide adjuvants: Active Material Form. No AF1 70% tetradecenyl succinic acid glucamide PEG 600 ester + 30% MPG AF2 70% octadecenyl succinic acid glucamide PEG 200 ester + 30% MPG AF3 70% tetradecenyl succinic acid glucamide PEG 600 ester + 30% MPG AF4 70% octenyl succinic acid glucamide PEG 600 ester + 30% MPG AF5 50% decenyl succinic acid diglucamide + 50% MPG AF6 decenyl succinic acid diglucamide (100%) AF7 50% octenyl succinic acid diglucamide + 50% MPG AF8 octenyl succinic acid diglucamide (100%) AF9 50% dodecenyl succinic acid diglucamide + 50% MPG notes: in the glucamide adjuvants listed above, glucamide groups are -N(methyl)(glucosyl) groups and PEG groups are polyethylene glycolyl groups of the stated approximate molecular weight. Example 1 Aqueous herbicide formulations were made up using GAS and GSS as the active agents and using various adjuvants. The formulations were made up as aqueous solutions containing: for glyphosate formulations: for sulphosate formulations: material amount material amount GAS 7.3 mi/ 1 GSS 6.7 ml.l '1 adjuvant 1 .8 ml.l "1 adjuvant 2.0 ml.l '1 composition composition water remainder water remainder The formulations were used in a test spraying programme in which the formulation was sprayed at an application rate of 300 l.ha "1 (thus providing 2.2 l.ha '1 GAS, equivalent to 1276 g.ha '1 active salt and 2.0 l.ha " GSS, equivalent to 1137 g.ha " active salt) onto field test plots containing growing plants of the weeds Erigeron canadensis (ERICA) and Lactuca saligna (LACSA) using 4 replications. The percentage of weed plants killed by the herbicide was assessed after 7, 14 and 28 days and was reported as the % efficacy. The formulations used and the weed control results obtained are summarised in Table 1 below. Table 1 Example 2 Aqueous herbicide formulations were made up using GAS and GSS as the active agents and using various adjuvants at the concentrations used in Example 1. The formulations were used in a test spraying programme in which the formulation was sprayed, at the rate described in Example 1 , onto greenhouse test plots containing growing plants of the weeds Chenopodium album (CHEAL), Sorghum halepense (SORHA) and Amaranthus retroflexus (AMARE) using 4 replications. The percentage of weed plants killed by the herbicide was assessed after 7, 14 and 28 days and was reported as the % efficacy. The formulations used and the weed control results obtained are summarised in Table 2 below. Table 2 Example 3 Example 2 was repeated using different adjuvants (and controls) and the formulations and results are summarised in Table 3 below. Table 3 Example 4 Example 1 was repeated using adjuvant AF5 (and controls) and the formulations and results are summarised in Table 4 below. Table 4

Claims: Claims 1 A method of killing weeds which are difficult to kill, which comprises applying to the weeds a herbicidal composition including as active herbicide a glyphosate type herbicide compound and as adjuvant a compound of the formula (I). (R 1 H).C.CO.NR 3 R 4 (I) 2 ' (R^H).C.CO.R where 1 2 one of R and R in the succinic acid moiety is C 6 to C 22 alkenyl or alkyl and the other is hydrogen; R is a polyhydroxy hydrocarbyl radical, R 4 is hydrogen or C, to C 22 hydrocarbyl; R 5 is a group: -NR R where R and R are independently as defined above, or 5 6 R is a group' -0.(AO) n .R where: AO is an alkylene oxide residue; n is 1 to 200; and R 6 is hydrogen or C, to C 22 hydrocarbyl. 2 A method as claimed in claim 1 where the compound of the formula (I) is a compound of the formula (la): (R 1 H).C.CO.NR 3 R 4 (la) (R 2 H).C.CO.NR 3 R 4 1 2 3 4 5 where R , R , R , R and R are as defined in claim 1 3 A method as claimed in claim 2 where in the compound of the formula (la) is a compound of the formula (la'): (R 11 H).C.CO.NR 13 R 14 (la') 12 ' 13 14 (R 12 H).C.CO.NR 13 R 14 where: one of R 11 and R 12 in the succinic acid moiety is C 6 to C 12 alkenyl or alkyl and the other is hydrogen; 13 each group R is a glycosyl group, particularly glucosyl group; and each group R 14 is hydrogen, or a C 1 to C 4 alkyl group. 4 A method as claimed in claim 1 where the compound of the formula (I) is a compound of the formula (lb): (R 1 H).C.CO.NR 3 R 4 (lb) 2 ' (R 2 H).C.CO.O.(AO) n .R 6 where R 1 , R , R , R 4 and R are as defined in claim 1 5 A method as claims in either claim 1 or claim 4 in which: R 3 is a glycosyl, particularly a glucosyl group; 4 where R is hydrocarbyl it is a particularly C 1 to C 20 alkyl group; AO is an ethylene oxide, residue; and where R 6 is hydrocarbyl it is C, to C 6 alkyl. @claim@6 A method as claims in any one of claims 1 to 5 in which the active herbicide is a glyphosate amine salt, particularly glyphosate /sopropylamino salt (Λ/-phosphonomethylglycine /sopropylamine salt). A method as claims in any one of claims 1 to 6 in which the weed species includes at least one broad leaved (dicotyledon) weed of one or more of the species Chenopodium album, Solanum nigrum, Lactuca saligna, Amaranthus retroflexus and Erigeron canadensis (annuals) and Cirsum arvense (perennial) and similar related weeds from these genera and/or at least one perennial monocotyledon weed of the species Lolium perenne, Convolvulus arvensis and Agropyron repens and similar related weeds from these genera. A method as claims in any one of claims 1 to 6 in which the herbicidal formulation includes at least one accessories or co-solvent. 9 A method as claimed in claim 8 wherein the at least one accessories or co-solvent is or includes a water soluble and/or miscible organic solvent for the adjuvant surfactant(s) which is a glycol, a low molecular weight polyglycol ethers or a mono alkyl ethers thereof and/or dimethyl isosorbide.

Inventors: AUDA MAHROUSSA, REEKMANS STEVEN IRENE JOZEF, AUDA, MAHROUSSA, REEKMANS, STEVEN, IRENE, JOZEF
Applicants: AUDA MAHROUSSA, ICI PLC, REEKMANS STEVEN IRENE JOZEF, AUDA, MAHROUSSA, IMPERIAL CHEMICAL INDUSTRIES PLC, REEKMANS, STEVEN, IRENE, JOZEF
Application year: 1997
Main classification: A01N57
IPC codes: A01N37, A01N57