United States Patent
`
`[19]
`
`Itzel et a1.
`
`[11] Patent Number:
`
`4,892,866
`
`[45] Date of Patent:
`
`Jan. 9, 1990
`
`[54] STABILIZED PESTICIDAL COMPOSITION
`
`[56]
`
`[75]
`
`Inventors:
`
`Hanshelmut Itzel, Gau-Algesheim;
`Manfred Dewenter, Badenheim;
`Siegfried Henke, Welgesheim, all of
`Fed. Rep. of Germany
`
`[73] Assignee:
`
`Shell Internationale Research
`Maatsshappij B. V., The Hague,
`Netherlands
`
`[21] App]. No.: 223,078
`
`[22] Filed:
`
`Jul. 22, 1988 V
`
`Foreign Application Priority Data
`[30]
`Aug. 7, 1987 [DE]
`Fed. Rep. of Germany ....... 3726339
`
`Int. cu ............................................. A01N 57/00
`[51]
`[52] US. Cl. .................................... 514/119; 514/970;
`514/971
`[58] Field of Search ........................ 514/119, 970, 971
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2,996,531
`3,090,719
`
`8/1961 Young ................................. 558/107”
`5/1963 Pinemonti et a1.
`.................. 514/119
`
`FOREIGN PATENT DOCUMENTS
`
`237004 10/1985 Japan .
`791824
`3/1958 United Kingdom .
`903159
`8/1962 United Kingdom .
`
`Primary Examiner—Allen J. Robinson
`
`. ABSTRACT
`[57]
`The invention provides a pesticidal composition com-
`prising, as active ingredient, dimethoate together with
`at least one inert carrier therefor, characterized in that
`the composition contains, as stabilizer, a cyclopropene
`fatty acid or an oil containing at least 1% w of a cyclo-
`propene fatty acid.
`
`4 Claims, No Drawings
`
`TIDE 1021
`
`1
`
`TIDE 1021
`
`

`

`1
`
`4,892,866
`
`STABILIZED PESTICIDAL COlVIPOSITION
`
`The invention relates to stabilised pesticidal composi-
`tions, and more particularly to the stabilisation of pesti-
`cidal compositions containing dimethoate.
`Dimethoate,
`0,0dimethyl-S-methylcarbamoyl-
`methyl phosphorodithioate, is a well-known and widely
`used systemic and contact insecticide. It is described,
`together with methods for its preparation, for example
`in UK Patent No. 791,824 and US. Pat. No. 2,996,531.
`One problem of dimethoate is that it is thermally unsta-
`ble and at temperatures of about 50' C. or more it can be
`subject to uncontrolled thermal breakdown, resulting in
`explosions. This is clearly a greater potential drawback
`in hot climates, and particularly in developing countries
`where storage facilities do not enable products to be
`protected from the sun's rays and where products are
`liable to be transported in open trucks and stored tem-
`porarily in the open.
`In such conditions unprotected storage, or storage for
`very long periods of time can easily result in products
`being unusable giving rise to problems of disposal, and
`in some cases fires have been caused by auto-ignition of
`stored products.
`It has now surprisingly been found that when dimeth-
`oate is stored in admixture with an oil containing a
`cyclopropene fatty acid significantly reduced thermal
`degradation can be observed.
`Accordingly the present invention provides a pestici-
`dal composition comprising, as active ingredient, di-
`methoate together with at least one inert carrier there-
`for, characterised in that the composition contains, as
`stabiliser, a cyclopropene fatty acid or an oil containing
`at least 1% w of a cyclopropene fatty acid.
`Typical examples of cyclopropene fatty acids are
`malvafic acid (2-octyl-l-cylopropene-l-heptanoic acid)
`(otherwise also known as malvic acid or halphen acid)
`and sterculic acid (2-octyl-l-cyclopropene-l-octanoic
`acid) (also known as sterculinic acid). Oils containing
`these acids can be extracted from seeds of the kapok
`tree (Cieba pentandra) (viz. kapok seed oil) and from
`Sterculia species, particularly Sterculia foetida. These
`acids are also to be found in other plants, e.g. durian
`(Dun'o zibethinus), gnemon (Gretum gnemon) and in
`species of the Malvaceae family.
`Preferably the stabiliser in a composition of the in-
`vention comprises malvalic or sterculic acid or oil from
`seeds of the kapok tree or from Sterculia species. The
`stabiliser may very conveniently be kapok seed oil.
`It is preferred for, the weight ratio of cyclopropene
`fatty acid(s): dimethoate in a composition of the inven-
`tion to be in the range 0.1:1 to 15:1, more preferably
`0.4:1 to 1:1, advantageously 0.5:1 to 0.7:1.
`When the stabiliser in a composition of the invention
`is kapok seed oil, the weight ratio kapok seed oil: di-
`methoate is preferably in the range 1:1 to 10:], more
`preferably 4:1 to 6:1.
`The invention also provides a method of stabilising a
`pesticidal composition comprising, as active ingredient,
`dimethoate together with at least one inert carrier there-
`for, the method comprising incorporating in the compo-
`sition, as stabiliser, a cyclopropene fatty acid or an oil
`containing at least 1% w of a cyclopropene fatty acid.
`Preferred methods of the invention employ the same
`stabilisers and weight ratios as indicated above in rela-
`tion to compositions of the invention.
`
`5
`
`10
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`15
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`20
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`25
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`30
`
`35
`
`45
`
`50
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`55
`
`60
`
`65
`
`.
`
`2
`Pesticidal compositions comprise at least one active
`ingredient together with at least one inert carrier there-
`fore, preferably at least two carriers, at least one of
`which is a surface-active agent.
`A carrier may be a solid or‘liquid material, which
`may be inorganic or organic and of synthetic or natural
`origin. Typical solid carriers include natural and syn-
`thetic clays and silicates, for example natural silicas, for
`example diatomaceous earths, and aluminium silicates,
`for example kaolinites, montmorillonites and micas.
`Typical liquid carriers are ketones, for example methyl-
`naphthalenes, petroleum fractions, for example petro-
`leum xylenes and light mineral oils, and chlorinated
`hydrocarbons, for example carbon tetrachloride. Mix-
`tures of liquids are often suitable. -
`One or more surface-active agents and/or stickers
`can be included in a pesticidal composition. A surface-
`active agent may be an emulsifying agent or a dispersing
`agent or a wetting agent; it may be non-ionic or ionic.
`Any of the surface-active agents usually applied in for-
`mulating insecticides may be used. Examples of suitable
`surface-active agents are the sodium and calcium salts
`of polyacrylic acids and lignin sulphonic acids; the con-
`densation products of fatty acids or aliphatic amines or
`amides containing at least 12 carbon atoms in the mole-
`cule with ethylene oxide and/or propylene oxide; fatty
`acid esters of glycerol, sorbitan, sucrose or pentaeryth-
`ritol, condensates of these with ethylene oxide and/or
`propylene oxide; condensation products of fatty alco-
`hols or alkyl phenols, for example p-octylphenol or
`p-octylcresol, with ethylene oxide and/or propylene
`oxide; sulphates or sulphonates of these condensation
`products; alkali or alkaline earth metal salts, preferably
`sodium salts, of sulphuric or sulphonic acid esters con-
`taining at least 10 carbon atoms in the molecule, for
`example sodium lauryl sulphate, sodium secondary
`alkyl sulphates, sodium salts of sulphonated castor oil,
`and sodium alkylaryl sulphonates, such as sodium dode-
`cylbenzene sulphonate; and polymers of ethylene oxide
`and copolymers of ethylene oxide and propylene oxide.
`A pesticidal composition may for example be formu-
`lated as a wettable powder, microcapsules, a dust, gran-
`ules, a solution, an emulsifiable concentrate, an emul-
`sion, a suspension concentrate or an aerosol. Composi-
`tions may have controlled release properties, or may be
`suitable for use as a bait.
`Wettable powders usually contain 25, 50 or 75% w of
`active ingredient and may contain, in addition to inert
`solid material, 3-10% w of a dispersing agent and,
`where necessary, 0—10% w of a stabiliser, a penetrant
`and/or a sticker. A dust is usually formulated as a dust
`concentrate having a composition similar to that of a
`wettable powder but without a dispersant, and is diluted
`in the field with further solid carrier to give a composi-
`tion usually containing 540% w of active ingredient.
`Granules usually have a size in the range of from 10
`to 100 BS mesh (1676-0152 mm) and maybe manufac-
`tured by agglomeration or impregnation techniques.
`Generally, granules will contain 545% w active ingre-
`dient and 0-10% w of additives, for example a stabiliser,
`slow release modifier and/or a binding agent.
`Emulsifiable concentrates usually contain, in addition
`to a solvent, and, when necessary, co-solvent, 10—50%
`w/v active ingredient, 2—20% w/v emulsifier and
`0—20% w/v of other additives, for example a stabiliser,
`a penetrant and/or a corrosion inhibitor. A suspension
`concentrate is a stable, non-sedimenting, flowable prod-
`uct and usually contains 10—75% w active ingredient,
`
`2
`
`

`

`4
`temperatures for up to 36 months. Results are given in
`Table I following:
`TABLE I
`
`% breakdown of dimethoate
`
`20' C.
`Temperature
`gambient)
`37' C.
`50' C.
`60° C.
`Formulation
`I
`A
`I
`A
`I
`A
`I
`A
`
`
`Period (months)
`1
`O
`1
`10
`0
`6
`40
`0
`12
`70
`0
`10
`0
`24
`
`
`
`
`0 40 036 100
`'strongly exothermic breakdown
`
`0
`
`80
`
`ll
`
`'
`
`The results given in Table I show the very much
`greater thermal stability conferred upon a formulation
`of dimethoate and cyclohexanone by the inclusion of an
`oil (kapok oil) containing cyclopropene fatty acids.
`We claim:
`1. A pesticidal composition comprising, as active
`ingredient, a pesticidally effective amount of dirnetho-
`ate together with at least one inert carrier therefor,
`characterized in that the composition contains a stabiliz-
`ing effective amount of a stabilizer comprising a cyclo-
`propene fatty acid, said stabilizer being selected from
`the group consisting of malvalic acid, sterculic acid, and
`oil from seeds of the kapok tree, from Sterculia species,
`from Durio zibethinus, from Gretvm gneman or from
`species of the Malvaceae family.
`2. A composition according to claim 1 wherein the
`stabilizer is selected from the group consisting of mal-
`valic acid, sterculic acid and oil from seeds of the kapok .
`tree or from Sterculia species.
`3. A composition according to claim 1 wherein the
`weight ratio of cyclopropene fatty acidzdimethoate is in
`the range of0.1:1 to 15:1.
`_4. A composition according to claim 1, 2 or 3 wherein
`the stabilizer comprises oil from seeds of the kapok tree,
`the weight ratio of said oil:dimethoate being in the ’
`range of 1:1 to 10:1.*
`*
`*
`*
`!
`
`4,892,866
`
`3
`0.5—15% w of dispersing agent, 0.1~10% w of suspend-
`ing agent, for example protective colloid and/or a thi-
`oxotropic agent, and 0—10% w of other additives in-
`cluding, for example, a defoamer, a corrosion inhibitor,
`a stabiliser, a penetrant and/or a sticker, and as disper-
`sant, water or an organic liquid in which the active
`ingredient
`is substantially insoluble; certain organic
`additives and/or inorganic salts may be dissolved in the
`dispersant to assist in preventing sedimentation or as
`anti-freeze for water.
`The aqueous dispersions and emulsions formed by
`diluting a wettable powder or an emulsifiable concen-
`trate are themselves pesticidal compositions. Such dis-
`persions and emulsions may be of the water-in-oil or of
`the oil-in-water type, and may have a thick “mayon-
`naise”-like consistency.
`Pesticidal compositions may also contain other ingre-
`dients, for example, one or more other compounds pos-
`sessing pesticidal, herbicidal or fungicidal properties, or
`attractants, for example pheromones or food ingredi-
`ents, for use in baits and trap formulations.
`_ The invention also includes a method of combating
`pests at a locus which comprises applying to that locus
`a pesticidal composition according to the invention.
`The invention will be further understood from the fol-
`lowing illustrative Examples.
`EXAMPLE 1
`
`A formulation of dimethoate was prepared by admix-
`ing components according to the following composi-
`tion.
`
` I % w/w
`
`Dimethoate
`1 1
`Cyclohéxanone
`34
`Kapok seed oil
`55
`(equivalent to 6—7% w/w
`cyclopropene fatty acids)
`
`For comparison purposes storage stability of formula
`I was monitored together with that of comparative
`formulation A, which consisted of 55.4% w/w dirneth-
`oate and 44.6% w/w cyclohexanone, over a range of
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`65
`
`3
`
`