CA1117132A

CA1117132A - Triorganotin compounds and method for combating insects using same

Info

Publication number: CA1117132A
Application number: CA000297818A
Authority: CA
Inventors: Melvin H. Gitlitz
Original assignee: M&T Chemicals Inc
Current assignee: M&T Chemicals Inc
Priority date: 1977-03-03
Filing date: 1978-02-27
Publication date: 1982-01-26
Also published as: AU514511B2; GB1579410A; DE2805987A1; BE864360A; FR2382457A1; SE7802325L; IT7809361A0; BR7801204A; IT1103083B; AU3343678A; ES467414A1; DK95778A; NL7802351A; JPS53108930A

Abstract

Abstract of the Disclosure - Tiorganotin compounds of the general formula are efficacious insecticides when applied to objects, particu-larly plants, that are susceptible to infestation by insects.
In the foregoing formula R1 and R2 are individually selected from the group consisting of linear and branched-chair alkyl containing from 1 to 4 carbon atoms with the proviso that the total number of carbon atoms in R1 and R2 is from 5 to 7, Y
is selected from the group consisting of chlorine, bromine, fluorine, hydroxyl, cyanide, carbamate, thiocarbamate, dithio-carbamate, nitrate, phenoxy, enolate, ,, SR3, OR4 , oxygen, sulfur. sulfate and phosphate, wherein R3 represents alkyl containing from 1 to 12 carbon atoms or phenyl, R4 is alkyl containing from 1 to 12 carbon atoms, a represents the valence of Y and is the integer 1, 2 or 3 and n represents an integer from 1 to 6, inclusive.

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Description

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NOVEI. TRIORGANOTIN COMP011MD~, AMD METHOD
FOR COMBATING IN'iEC'rS U''ING SAME
BACKGROUND OF '~HE INVENTION
Thls invention relates to a method for selectively controlling insects using a specified class of triorganotin compounds. The insects against which the compounds are effective are responsible for a considerable portion o~ the annual damage to agricultural crops. Many tri-n-alkyltin compounds, particularly tri-n-butyltin deri~atives ~ay effectively control these insects to some extent, however, these compounds are sufficiently non-selective toward desirable plant crops in that while the lnsect attacking the plant may be controlled, the plant to which the compound is applied is often killed or severely damaged. Thus, tri-n-alkyltin compounds wherein the hydrocarbon radicals contain from 1 to 4 carbon atoms cannot be employed as pesticides on agr~cultural crops.
It has now been found that a novel class of tri(sec-alkyl)tin compounds effectively control insects which J
attack agricultural crops, yet do not seriously damage the plants at the use levels required to control these insects.

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'7132 'rhls invention provides a method ror controlling insects by applying directly to the insects or to locations susceptible to inPestation by these lnsects a composi.tion consisting essentially o~ an inert liquid or solid carrier and an insecticidally ef:~ective amount of' a tri(sec-alkyl) tin compound o~ the general ~ormula _~ n Y

wherein Rl and R are individually selected f'rom the group consisting of' linear and branched-chain alkyl containing f'rom 1 to 4 carbon atoms with the proviso that the total number of carbon atoms in R and R is f'rom 5 to 7, Y is selected f'rom the group consisting of' chlorine, bromine, fluorine, hydroxyl, cyanide, carbamate, thiocarbamate, dithiocarbamate, nitrate, O O O
,. - ..
B phenoxy, enolate~ -OCR , -OC(C~2) CO-, SR , OR , oxygen, sulf'ur, sulfate and phosphate, wherein R represents alkyl containing f'rom l to 12 carbon atoms or phenyl, R is alkyl containing f'rom 1 to 12 carbon atoms, a repre-sents the valence of Y and is the integer 1, 2 or 3 and n represents an integer from 1 to 6, inclusive.
In another aspect, the invention provides a composition of' matter : comprising a tri(sec-alkyl)tin compound of the general f'ormula ~ 2 ) - S~ ~ Y

either alone or in admixture with an inert solid diluent or carrier, a lique~ied normally gaseous diluent or carrier, or in admixture with a liquid diluent or carrier containing a surface active agent, wh~rein R , R , Y
and a are as def'ined above.

. RS(/~0',5 j ~ 132 NOVEL TRIoRGAr1oTIll COMPOIJM~S AN~ METIIOD
FOR COMBATI~JC I~l~')ECiTS IJSIN~ SA-i~E
DETAILED DESCRIPTIOrl OF THE INVENTION

The three hydrocarbon groups of the present triorganotin compounds contain a secondary carbon atom that ls bonded to a hydrogen atom and two alkyl groups~ each of whlch contains from 1 to 4 carbon atoms. The remaining valence of the secondary carbon atom is satisfied by a bond to the tin atom. Preferred sec-alkyl groups lnclude 2-pentyl, 3-pentyl, 2-hexyl, 3-hexyl and 4-methyl-2-pentyl.
l The tri(sec-alkyl)tln halides wherein the halogen is ¦ chlorine, bromine or iodine are prepared by reacting at least , three moles of the corresponding sec-alkyl magnesium halide, I ~ t 1 Z
I R -C-MgZ , for every mole of an alkyltin trihalide RSnZ3.
j R2 ~ The alkyl radical is linear and contains ~rom one to eight ¦ carborl atoms.

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The resultant tetraorganotin compound, ¦R ~C~ SnR

¦ ~ /3 ¦ wherein R represents the alkyl residue from the aforementioned alkyltin trihalide is reacted with an equimolar amount o~ a stannic halide, SnZ4. During the reaction the lower alkyl residue R present on the tetraorganotin compound is replaced by a halogen atom from the stannic halide. The reactions lnvolved in the formation o~ the present triorganotin compounds can be represented by the following two equations where Z , 25 ~ Z and Z are lndividually selected from the group conslsting Or chlorlne, bromine and iodine.

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H / H \
3 R -C-~lgZ + Rsnz2 ~Rl-C - J SnR + 3MgZlZ2 ~R-C SnR + SIIZ4 ~Rl-C ~ 5nZ3 + R5nZ3 The aforementioned aIkyltin trihalide RSnZ3 can, in turn, be pre-pared by reacting the corresponding aIkyl halide, ~zl, with a stannous halide SnZl as described in United States Patent 3,340,283.
It is known to prepare tri(linear aliphatic)tin halides wherein all the organic groups are identical by reacting the corresponding tetra(linear aliphatic)tin ccmpound with an equimolar amount of the desired stannic halide.
m is process is described in an article by R. K. Ingham et al. that appeared in the October, 1960 issue of Chemical Reviews beginning at page 485. This procedure is not feasible for preparing the secondary aIkyl com~ounds of this invention because of deco~position which occurs at the relatively high temperatures required to effect the redistribution reaction using a tetra-organotin compound of the general formula ~R -C ~ Sn. Surprisingly it has now been discovered that if one of the four secondary aIkyl groups is re-placed by a linear alkyl group, represented by R in the foregoing formula, the R grONp can be selectively replaced by a halogen atom from a stannic halide. m e temperature required to effect this reaction is considerably lower than that required to react a tetra(secalkyl)t m ccmpound. m e undesir-able decomposition is thereby avoided and the product is obtained in yields of 90% or more.
m e reaction between the stannic halide and the asy~metric tetra-organotin compound should be performed under ~ l3~ ~

anhydrous condition.s at kemperatures from about -25 to 80C., prererably rrom ~25 to 80C. in a hydrocarbon solvent. Preferred solvents include pentane, hexane, cyclohexane and benzene.
The stannic hallde is dissolved in an organic solvent and the resultant solution is added dropwise to a second solution containing the tetraorganotin compound in the same solvent. The temperature of the reaction mixture is preferably malntained below about 30C. during the addition, ¦ which requires about one hour, after which the mixture is I heated to a temperature from 35 to 80C. The temperature conveniently employed is the boiling point of the reaction mixture. Heating is continued for from about 15 to 60 ' minutes to ensure complete reaction. The reaction mixture is I then allowed to cool to ambient temperature, and extracted with one or more portions of water or aqueous mineral acid.
The Dy-product of the reaction, a monoorganotin trihalide, RSnZ3, is soluble in aqueous media. The desired product remains in the organic phase, and is readily isolated by ! boiling off the hydrocarbon solvent. No further purification is usually required, however the product can be distilled if deslred. The organic layer is freed of any dissolved water following the extraction step. Any of the conventional , chemi¢al dehydrating agents are suitable, provided that they l will not react with either the triorganotin halide or the l hydrocarbon solvent. Preferred drying agents lnclude anhydrous magnesium sulfate, anhydrous sodium sulfate and anhydrous calcium sulfate.

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The present trlorganotln halldes are liquids at amblent temperature. The halldes can readily be converted to other derlvatives such as the oxlde, acetate and sulfate using known reactions. The desired anionic radical can be introduced by reactin~ the corresponding triorganotin halide, ¦ hydroxide or bis(triorganotin) oxlde with the reagent ¦ indicated in the following table. J
¦ ORGANOTIN DERIVATIVE + R~AGENT -~ DESIRED PRODUCT
1 Chloride, Bromide Carboxylic acid + carboxylate~
' or Iodide acid acceptor, e.g. e.g. acetate pyridine alkali metal salt Or 1, a carboxylic acid Il " aqueous solution of oxide (or ~ alkali metal hydroxide hydroxide) Ji, " alkali metal alkoxide alkoxide i, or alcohol + acid acceptor (e.g. an ~ amine) ' " alkali metal phenoxide phenoxide or phenol + acid acceptor " potassium fluoride or fluoride I hydrofluoric acid ,~ " alkali metal sulfide sulfide " alkali metal sulfate sulfate mercaptan + acid mercaptide acceptor " alkali metal cyanate cyanate " al~ali metal thiocyanate thiocyanate " alkali metal thiocarbamate thiocarbamate '1 alkali metal dithiocarbamate dithiocarbamate l~ Z

ORGANOTIN DERIVATIVE + REAGENT -~ DESIRED PRODUCT
"",....

Chlorlde, Bromide . phosphoric acid phosphate or lodide or alkall metal phosphate s!r alkali metal dialkyldi~hlo-dialkyldithlo- I phosphate phosphate Oxide or Hydroxide carboxylic acid or carboxylate anhydride " alcohol tor phenol) alkoxide tor.
phenoxide) " hydrofluoric acid fluoride " dilute t10-25 weight sulfate %) aqueous sulfuri¢ acid " hydrogen sulfide sulfide " alkyl or aryl mercapkide mercaptan : " carbon dioxide carbonate Hydroxlde water oxide - .

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The reaction conditions such as preferred solvents, temperatures and reaction tlmes for preparing the derivatives ~ummarized in the precedlng table are known in the art and, therefore, do not require a detailed description in the present specification. A comprehensive treatment of this sub~ect matter together with numerous :Literature references is contained in an article by R. K. Ingham et al. that appeared in the October, 1960 issue of CHEMICAL REVIEWS (pp. 459-539). The aforementioned derivati~es may be liquids or sol.lds at ambient ¦I temperature, depending upon the type of substituents . represented by Y. Z
. The present tri(sec-alkyl)tin compounds effectively control many types of undesirable insects when applied to ¦l living plants that are susceptible to infestation by these .1 insects. The present compounds are particularly effective ¦l against insects of the order homoptera, including aphids, and j¦ the larval stage of the order lepodoptera, which includes .1 the cabbage looper, corn borer and the bollworm larva. Z
i Some of the compounds effectively control the two-spotted spider ,; mite (Tetrancychus bimaculatus). A single application of these compounds to living plants or other substrates can provide residual and extended control of many varieties of insects for a considerable period of time, the duration of which is dependent to some extent upon mechanical and biological in~luences, i.ncluding weather. Formulations containing the Z
present organotin compounds can be applied directly to the lnReot be cont lled.

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In preparing compositions for application to plantæ
the organotin compound is often augmented or modified by combining it with one or more commonly employed pesticide addltives or ad~uvants including organic solvents, water or other llquid carriers, surfactants to aid in dispersing or emulsifying the organotin compound or particulate and finely comminuted or divided solid carriers. Depending wpon the concentration of triorganotin compound in these compositions, they can be employed either without additional dilution ll or as lia~uid concentrates which are subsequently diluted with one or more additional inert liquids to produce khe ultimate treating compositions. In compositions employed as concen-trates, the triorganotin compound can be present at , concentrations of from about 5 to about 98% by weight. Other biologically active agents that are chemically compatible i! with the present triorganotin compounds can also be added.
The optimum effective concentration of tin compounds ~, to be employed as toxicant in a composition is dependent s¦ upon whether the insect is contacted with or ingests the toxicant. The actual weight of compound constituting an effective dose is primarily dependent upon the susceptibility of a particular insect to a given triorganotin compound. For control of the cabbage looper (Trîchoplusia ni), good results are obtained with liquid or dust compositions containing as little as 25 parts per million by weight of toxicant.
Compositions containing up to 90 percent by weight of toxicant can be employed to treat a heavily infest~d area.

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In the preparation Or dust cornpositions~ the organo-tin compound can be blended w:Lth many commonly employed finely dlvlded solid carriers such as fullerl 8 earth, attapul~ite, bentonite, pyrophylllte3 verrnlculite, diatomaceous earth, talc, chalk, gypsum and wood flour. ~he carrier, usually in a ~inely divided form, is ground or mixed with the toxlcant or wetted with a dispersion of the toxicant ln a volatile liquid. Depending upon the relative proportions of toxicant and carrier, these compositions can be ernployed as concentrates that are subsequently diluted with additional solid carrier to obtain the desired amount of active ingredient.
Alternatively, such concentrate dust compositions can be employed in combination with various known anionic, cationic or non-ionic surfactants as emulsifying or dispersing agents to form spray concentrates. Such concentrates are readily dispersible ln liquid carriers to form spray compositions or llquid formulations containing the toxicants in any desired amount. The choice and concentration of surfactant are ¦ determined by the ability of the material to facilitate the : ~ 20 1¦ dispersing of the concentrate in the liquid carrler to produce il the desired liquid composition. Suitable liquid carriers include water, methanol, ethanol, isopropanol, methyl ethyl ketone, acetone, methylene chloride, chlorobenzene, toluene, xylene and petroleum distillates. Among the preferred petrolleum distillates are those boiling under 400F. at atmospheric pressure and having a flash point above about 80F. !

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Llquid compositions can also be prepared by dlssolvlng one o~ the present triorganotln compounds in a mlxture contalning a water-immlscible organic liquid and a urface active dispersing agent. The resultant emulsiriable concentrate is then further diluted with water and an oil to form spray mixtures in the ~orm of oil-in-water emulsions.
In such compositions, the carrier compr~ses an aqueous emulsion, i.e. a mixture of water-immiscible solvent, emulsifying agent and water. Preferred dispersing agents for 1l these compositions are oil soluble and include the 1~ condensation products of alkylene oxides with phenols and ! organic and inorganic acids polyoxyethylene derivatives o~
sorbitan esters, alkylarylsul~onates, complex ether alcohols, ,~' mahogany soaps and the like. Suitable organic liquids to be ii employed in the compositions include petroleum distillates, ii hexanol, liquid halohydrocarbons and synthetic organic oils.
¦ The surface active dispersing agents are usually employed in ~¦ the liquid dispersions and aqueous emulsions in the amount o~
!i from about 1 to about 20 percent by weight of the combined weight of the dispersing agent and the active toxicant.
When operating in accordance with the present ~¦ invention~ the organotin compound or a composition containing the compound can be applied directly onto the undesirable I insect or to the site to be protected, particularly plants and trees. Application to the ~oliage of plants is convenient~y carried out using power dusters, boom sprayers and spray dusters. When employed in this manner the compositions should not contain any signi~icant amounts Or phytotoxic diluents. In large scale operatlons, dusts or low volume sprays may be applied rrom an alrcraft.
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The rollowlng examples represent pre~erred embodlments of the present compounds and their use as lnsecticides, and are not intended to limit the scope of the accompanying claims. All parts and percentages are by welght unless otherwise specified.
EXAMPLES

EXAMPLE 1 - Preparatlon of Tr:1(3-pentyl)tin Chloride A. Preparation of Methyl Tri(3-pent~l)tin To 16 g. (0.66 g. atom) of magnesium turnings maintained at a temperature of 25C. under a nitrogen atmosphere was added a 25 cc. portion of a solution con~aining 99.7 g. (o.66 mole) of 3-bromopentane dissolved in 300 cc. of anhydrous tetrahydrofuran. The reaction was initiated using a few drops of ethylene dibromide. The remaining portion of the 3-bromopentane solution was gradually added during a ~ period of one hour while the reaction mixture was heated to the boiling point. Heating was continued for an additional .
hour. The reaction mixture was then allowed to cool to ambient temperature, at which time all of the magnesium appeared to have reacted. The resultant solution contained o.6 mole of 3-pentyl magnesium bromide, and was added dropwise to a stirred solution of methyltin trichloride (49 g., a. 2 mole) dissolved ln 50 c of dry be~zene. The addi'ion -equiFed 0.5 hour and .
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was conducted under a nitrogen atmosphere. During the addltion the temperature of the reaction mixture rose to 71C.
Following completion of the addition the reaction mixture was heated to the boiling point for one hour, then allowed to coo} to ambient temperature. To the resultank mixture was added a solution containing 250 cc. water and 15 cc.
concentrated sulfuric acid over a five minute period. The aqueous phase was separated and the residual was removed by combining the organic phase wlth a portion of anhydrous magnesium sulfate, which was subsequently removed by filtration. The solvent was evaporated under t reduced pressure to yield 58~8 g. (85% yield) o~ a yellow liquid exhibiting a refractive index (n D) of 1.4954. This product was extracted twice wi~h methanol and distilled under reduced pressure. rne fr~cbion boiling from 81 to 87C. ~ier a pressure of 0.15 mm. was isolated and exhibited a refractive index (n V) f 1.l,920. Analysis by vapor phase chPomatography indicated that the product was 95.7% pure.
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B. Cleava~e of Methyl Tri(3-pentyl)tln to Trl(~-pentyl)tin Chlorlde A 20.8 g. (0. o6 mole) portion o~ the methyl tri(3-pentyl)tin prepared as described in part A o~ this example was dissolved in 50 cc. o~ pentane. To this solution was added a solution containing lS.6 g. (o.o6 mole) of stannic chloride and 50 cc. pentane. The addition required 20 minutes, following which the resultant mixture was heated ~ to the boiling point (40C.) for 45 mlnutes and then allowed to~
, cool to ambient temperature. A solution obtained by combining

2 cc. af 12N aqueous hydrochloric acid and 200 cc. water was then added to the reaction mixture with vigorous stirring both during the addition and for three minutes therea~ter.
The organic layer of the resultant two-phase liquid was isolated and combined with an aqueous hydrochloric acid solution prepared as described hereinabove. The organic layer was again isolated and the water therein removed using a quantity of anhydrous magnesium sul~ate. The pentane was -' then evaporated under reduced pressure to yield 21.6 g. of a yellow liquid exhibiting a re~ractive index (n D) of 1.5060.
Upon analysis the product was ~ound to contain 32.04% tin and 9.42% chlorine. The calculated vaIues for tri(3-pentyl)tin il chloride are 32.29% tin and 9.64% chlorine.
~ Bis~tri(3-pentyl)tin] oxide was prepared by adding a solution of the corresponding chloride (37. Ii g. of the chloride ln 100 cc. of a solution containing equal volumes of methanol and ethanol) to a solution containing 16.0 g. of sodium hydroxide, 50 cc. water and 50 cc. methanol. The addition was gradual and required 15 minutes. The resultant ' -. 1.

cloudy solution was heated to the bolling point for 15 minutes, after which lt wa~ allowed to cool to amblent temperature. A 400 cc. portion of water followed by 300 cc.
of diethyl ether were added while the mixture was vlgorously stirred. The ether layer of the resultant two-phase liquid was freed of water uslng anhydrous magnesium sulfate, after which the drying agent was removed and the ether evaporated by heating the mixture under reduced pressure. The residual yellow liquid weighed 34.9 g. and was found to contain 34.62 tin and no chlorine. Pure bis~tri(3-pentyl)bin] oxide 1~ contains 34.95% tln. Analysis by potentiometric titration I indicated that the oxide was 93.4% pure.

Ii 3 5I ExamPle 2 - Preparation of Tri(2~pentYl)-, Tri(3-hexYl) I! and TriS(4 methyl-2-pentyl)tin Chlorides and Oxides Each of the title compounds were prepared from a corresponding methyl tri(sec-alkyl)tin compound as described in Example 1. The reagents employed and the properties of the i intermediate tetraorganGtin compound, chloride and oxide are 'j set forth in the following tables.
,, The aforementioned intermediate tetraorganotin i3 compounds were prepared in the usual manner ~rom methyltin trichloride and the corresponding Grignard reagent in the quantities shown below.

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TABI~ I
Preparation of Tetraorganotin Compounds Pro~uct G ~ Moles MeSnC13 Prod. Wt.
Me-thyltri(2-pen-tyl)tin 2-Pentyl MgBr 1 72 68.9 g.*
Methyltri(3-hexyl)tin 3-Hexyl MgBr 1 72 69.8 g.*
Methyltri(4-methyl-2- 4-Methyl-2~ 1 72 73.3 g.*
(pentyl)tin pen-tyl MgBr *follcwing disti:Llation TABLE II
Properties of Tetraorganotin Cor~ounds Intermediate Found Theory ~ B.P. @ Pressure Compound % Sn % Cl % Sn % Cl VPC % (mm. of Hg.~ ~D
Methyltri 34.28 0.12 34.19 0.0 96.2 88-92 @ 0.07 1.4835 @ 21 &.
(2-pentyl)tin Mbthyltri 30.25 0.65 30.50 0.0 93.6 107-114 @ 0.4 1.4904 @ 19C.
(3-hexyl)tin Methyltri 29.28 0.11 30.50 0.0 95.1 103-107 @ 0.15 1.4765 @ 26C. (4-methyl-2-pentyl)tin TABLE III
Preparation of the Tri(sec-aIkyl)tin Chlorides Final Product Product Intermediate Wbight SnCl~Wt. Weight (g-) (g-) Tri(2-pentyl) Methyltri(2-pentyl)tin 20.8 15.6 21.4 g-tin chloride Tri(3-hexyl) Methyltri(3-hexyl)tin68.1 45.6 70.6 g.
tin chloride Tri(4-methyl- Methyltri(4-methyl 71.6 47.9 74.6 g.
2-pentyl)tin 2-pentyl)tin chloride 7~3~:

TABLE LV
Properties of the Tri(sec-a]~yl?tLn Chlorides Found r~eory A s~ n % Sn % Cl % Sn % Cl VPC % D
Tri(2-pentyl)tLn Chloride 32.34 9.28 32.29 9.65 95.6 1.4956 @ 25C.
Tri(3-hexyl)tin Chloride 28.94 8.67 28.97 8.65 95.9 1.5005 @ 21 C.

rri(4-methyl-2-pentyl)29.02 8.70 2~.97 8.65 94.2 1.4900 @ 23C.
tin Chloride rrhe orgc~notin chlorides shown in Table 4 were converted to bis-oxide deriva-tives in a manner essentially sunilar to that described above for bis(tri-3-pentyl)tin oxide. Properties of these materials are shown in Trihle 5 below.
TABLE V
Properties of Bis[tri(sec-alkyl)tin]oxides Found meory Assay*
Product~ Sn % Cl ~ Sn % Cl % ~D
= . = . . .
Bis[tri(2-pentyl)tin] 34.58 0 34~95 0 99.6 1.5000 @ 21 C.
oxide Bis[tri(3-hexyl)tin] 30.90 0.01 31.06 0 99.5 1.5028 @ 22 &.
oxide Bis[tri(4-methyl-2- 30.89 0 31.06 0 100 1.4914 @ 22 C.
pentyl)tin] oxide *by potentiometric titration . 1~ 3%

EXAMPI,E 3 - Biological Actlvlty o~ Tri(sec-alkyl)tin Compounds The efflcacy Or five of the compound~ disclosed in the foregolng examples in controllin~ a number o~ undesirable insects was evaluated using one or more of the test procedures summarized hereinafter.

TEST PROCEDURES
A. The insect is placed in an aqueous dispersion containing a specified concentration of the organotin compound.
Contact time is two seconds. The larvae were then set aside for six days, at which time the percent mortality was observed.
B. A bean plant is sprayed with an aq~eous dispersion containing a specified concentration of organotin compound. The test insect is placed on the treated foliage and remains undisturbed for three days, at which time the percent mortality is observed.
C. A bean plant infested with the insect is sprayed and remains undisturbed for three days, at which time the percent mortality is observed.
D. Five third instar bollworm larvae are placed in petri plates containing a layer of semi-synthetic diet. These larvae are sprayed with 3 cc. of a solution or suspension containing 400 parts per million (ppm) of the chemical. The spraying is accomplished from a distance of 15 inches (38 cm.) ~ using a Spraying Systems Company nozzle type 40100-120. After spraying, the petri dish cover is replaced with a fiber brewer , lld to permit limited alr exchange. A mortality count is taken~
followlng a holding period of up to three days.

~'7~

The concentrations of active compound in the following tables are expressecl in parts per mlllion (ppm) o~
total dlspersion.
TABLE 6 ' Activitv Against Cabba~e Looper (Tricho~lusia~
Compound Procedure %mortality @ ~ ppm o~ compound x=400 100 `
Tri(3-hexyl)tin chloride A100 80 B100 100 ~ I
Bis~tri(3-pentyl)tin] oxide A100 100 3 Bis[tri(2-pentyl)tin] oxide A100 100 Il B100 0 , Bis~tri(4-methyl-]-pentyl~tin] A100 100 i oxide . B100 100 Bls[tri(3-hexyl)tin] oxide A100 100 .

li ¦i TABLE 7 ll Activity Against Aphids , Uslng Procedure C .
Compound % mortality @ 100 l ppm of Compound i Tri(3-hexyl)tin chloride 100 Bis~tri(3-penyl)tin~ oxide 100 I Bis[tri(4-methyl-2-pentyl)tin] oxide 100 j~ 31s~trl 3-hexyl)tln] oxlde 100 ' . I

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Activity A~ainst Bollworm Larvae (Heliothis zeae) U8 in~ Procedure D
~ % mortality @ lloo ppm of compound Tri(3-hexyl)tin chloride 80 Bis[tri(3-pentyl)tin] oxide 80 Bis[trl(2-pentyl)tin] oxide 60 Bls[tri(4-methyl-2-pentyl)tin] oxide 60 Bis~tri(3-heY.yl)tin] oxide 100 Actlvity A~ainst Two-SPotted Spider Mite Using Procedure C With Tric~clohexyltin Hydroxide As A Control -Compound % mortality rate (ppm compound) 4~0 200 100 50 25 12.5 Bis[tri(3-pentyl)tin] oxide 99 99 96 95 94 38 Tricyclohexyltin hydroxide 100 100 99 98 55 o . I
The foregoing data demonstrate that at concentrations below 50 parts per million the present compounds are superior ¦¦ to tricyclohexyltin hydroxide, a commercial miticide. At a ¦ level of 25 parts per million bis[tri(3-pentyl)tin] oxide was almost twice as efficacious as the control. In practical terms, this means that less of the present compounds are ~25 required to effectively control spider mites relative to prese oonmerc1ally ava11~ble tr~organotin compounds.

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Claims

WHAT IS CLAIMED IS:

1. A tri(sec-alkyl)tin compound of the general formula wherein R1 and R2 are individually selected from the group consisting of linear and branched-chain alkyl containing from 1 to 4 carbon atoms with the proviso that the total number of carbon atoms in R1 and R2 is from 5 to 7, Y is selected from the group consisting of chlorine, bromine, fluorine, hydroxyl, cyanide, carbamate, thiocarbamate, dithiocarbamate, nitrate, phenoxy, enolate, -NH2, , , SR3, OR4, oxygen, sulfur, sulfate and phosphate, wherein R3 represents alkyl containing from 1 to 12 carbon atoms or phenyl, R4 is alkyl containing from 1 to 12 carbon atoms, a represents the valence of Y and is selected from the integers 1, 2 and 3, and n represents an integer from 1 to 6, inclusive.

2. A tri(sec-alkyl)tin compound as set forth in Claim 1 wherein R1 is methyl or ethyl and R2 is ethyl, n-propyl or iso-propyl.

3. A tri(sec-alkyl)tin compound as set forth in Claim 1 wherein said compound is selected from the group consisting of tri(3-hexyl)tin chloride, bis[tri(3-pentyl)tin]
oxide, bis[tri(2-pentyl)tin] oxide, bis[tri(4-methyl-2-pentyl)tin] oxide and bis[tri(3-hexyl)tin] oxide.

4. A method for controlling undesirable insects by applying directly to the insects or to loci inhabited by or susceptible to infestation with said insects of a composition consisting essentially of an inert liquid or inert solid carrier and an insecticidally effective amount of a tri(sec-alkyl)tin compound of the general formula wherein R1 and R2 are individually selected from the group consisting of linear and branched-chain alkyl containing from 1 to 4 carbon atoms with the proviso that the total number of carbon atoms in R1 and R2 is from 5 to 7, Y
is selected from the group consisting of clorine bromine, fluorine, hydroxyl, cyanide, carbamate, thiocarbamate, dithiocarbamate, nitrate, phenoxy, enolate, -NH2, , , SR3, OR4, oxygen, sulfur, sul-fate and phosphate, wherein R3 represents alkyl containing from 1 to 12 carbon atoms or phenyl, R4 is alkyl containing from 1 to 12 carbon atoms, a represents the valence of Y and is selected from the integers 1, 2 and 3, and n represents an integer from 1 to 6, inclusive.

5. A method for controlling undesirable insects as set forth in Claim 4 wherein R1 is methyl or ethyl and R2 is ethyl, n-propyl or iso-propyl.

6. A method for controlling undesirable insects as set forth in Claim 4 wherein the tri(sec-alkyl)tin compound is present at a concentration of from 25 to 1000 parts by weight per million parts of said composition.

7. A method for controlling undesirable insects as set forth in Claim 4 wherein X is halogen.

8. A method for controlling undesirable insects as set forth in Claim 7 wherein X is chlorine.

9. A method for controlling undesirable insects as set forth in Claim 4 wherein Y is oxygen.

10. A method for controlling undesirable insects as set forth in Claim 4 wherein the inert diluent is a liquid.

11. A method for controlling undesirable insects as set forth in Claim 10 wherein water constitutes more than 50% by weight of said liquid.

12. A method for controlling undesirable insects as set forth in Claim 4 wherein the tri(sec-alkyl)tin compound is selected from the group consist-ing of tri(3-hexyl)tin chloride, bis[tri(3-pentyl)tin] oxide, bis[tri(2-pentyl)tin] oxide, bis[tri(4-methyl-2-pentyl)tin] oxide and bis[tri(3-hexyl) tin] oxide.

13. A method for controlling undesirable insects as set forth in Claim 4 wherein said loci are living plants.