Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
iL~84837
This invention relates to the control of insects.
This invention further relates to compositions for controlling
insects ~nd aoarids that can be applied directly to these
organisms, their eggs or to substrates, particularly plants,
that are infested with these organisms.
Numerous phospho~us compounds have been disclosed as
being effective control agents for insects and acarids. For
example, United States Patent 2,754,242 teaches using alkyl
bis (halophenyl) phosphinates to kill two-spotted spider mites.
Many of these ~ompounds are not practical for commercial use,
since they must be present at relatively high concentration
levels (500 parts per million or more) to be effective. The
in-use cost of these prior art materials may therefore be so
high as to exclude them for large-scale applications.
It has now been found that certain tertiary bis-
(halophenyl)phosphines, phosphine oxides and phosphine sulfides
are remarkable effective insecticides and acaricides that can
be employed at lower concentration levels than heretofore
possible using many structurally related prior art materials,
including those disclosed in the aforementioned United States
Patent 2,754,242.
~'
1084837
Su~mary of the Invention
This invention provides a method for killing
B insects and sterilizing eggs of insects and acar~d~ by applylng
to said insects, said eggs or to substrates susceptible to
infestation with said insects or aoaride an insecticidally and
ovicidally effective amount of a phosphorus compound exhibiting
the formula:
Z =P-R P-R -
(~)or (~!
! wherein R is selected from the group consisting of alkyl
Il radicals containing ~etween 1 and 12 carbon atoms, alkenyl
~j and alkynyl radicals containing between 2 and 12 carbon atoms,
¦: cycloalkyl, aryl, alkaryl, aralkyl and haloalkyl radicals,
! x represents a halogen atom selected from the group consisting
of fluorlne, chlorine, bromine and iodine atoms and Z represents
~j oxygen or sulfur. .
¦~ ~etailed Description of the Invention
j The present insecticides and ovicides are tertiary
bis(p-halophenyl)phosphines, phosphine oxides and phosphine
;I sulfides. When R of the preceding formulae represents an
I alkyl radical, it may contain one or more halogen atoms as
~08~837
substituents. These compounds effectlvely control insects at
considerably lower concentrations that can be achieved uslng
structurally related compounds, such as the aforementioned
j bisthalophenyl)phosphinates that are disclosed in the chemical
~ and patent literature. The comparative efficacy of the present
compounds and the criticality of the substituents on both the
phenyl radicals and the phosphorus atom are demonstrated in the
accompanying examples. In addition to killing the nymph and
adult stages of insects, the present compounds also inhibit
o l! development o the eggs of both insects and acarids. At lower
j, concentrations the present compounds function as chemosterilants.
!I While many known insecticides and ovicides are
ii effective when sprayed onto infested plant leaves, the present
il compounds are unique in that they can also be applied to the
~I soil surrounding the roots of the plant and are transported
by the plant to the leaves, where insects and eggs are killed.
Many of the present tertiary bis(halophenyl)phosphines
j are disclosed in the chernical literature. The phosphines are
!I conveniently prepared by reacting the appropr-iate halophenyl
~1~ magnesium halide arid dichloroorganophosphine. The dichloro-
organophosphines are either available from commercial suppliers
l~ or can be synthesized using known preparative methods, for
!, example those disclosed in "Organophosphorus Compounds" by
! G. M. Kosolapoff, published by John Wiley and Sons, Inc.
,~
1084837
The resultant bis(halophenyl)organophosphlne is readlly
converted to the corresponding phosphine oxide or phosphine
sulfide by reacting the phosph~ne with hydrogen peroxide or
elemental sulfur, respectively.
Alternatively, the phosphine oxides can be prepared
directly from a halophenylmagnesium halide by reacting it
"` ,. O
with the appropriate organophosphonic dichloride, RPC12
The following examples provide specific methods for
preparing and using representative compounds encompassed by the
accompanying claims. All parts and percentages are by weight.
Example 1 - Bis(p-chlorophenyl)methylphosphine Oxide
To 900 cc. of a sol~tion containing 1.143 moles of
p-chlorophenylmagnesium bromide dissolved in tetrahydrofuran
was added 73 g. (0.55 mole) of methylphosphonic dichloride
O
- !
(CH3PC12) dissolved in 400 cc. of tetrahydrofuran. The addition
required two hours, during which time the reaction mixture was
stirred and the temperature maintained at between 30 and 40C.
Following completion of the addition the re~ction mixture was
, heated to the boi~ing point for one hour, cooled and then
20 j extracted using 2 liters of chloroform. The chloroform layer
was then dried using anhydrous magnesium sulfate and the solvent;
removed under reduced pressure. The solid residue was re-
crystallized once from benzene to yield 90 g. of a white
sol1d that el'ed between 167 and 169C. Analy~1~ of the
_4_
I
l . ,~,,. ,
:
.
~084837
recrystallized product revealed a phosphorus content of 10.9
I and a chlorine content of 22.3%. The calculated phosphorus
¦ and chlorine content of bis(p-chlorophenyl)methylphosphine
~l~ oxide ls 10.9 and 24.9%, respectively. The structure of the
compound was confirmed by nuclear magnetic resonance.
Example 2 - Bis(p-chlorophenyl)chloromethylphosphine Oxide
To a solution containing 69 g. (0.39 mole) of
chloromethylphosphonic dichloride and 400 cc. tetrahydrofuran
~ was added 285 cc. of a tetrahydrofuran solution containing
10 ~l 0.789 mole of p-chlorophenylmagnesium bromide. The addition
was dropwise and required two hours, during which time the
temperature of the reaction mixture was maintained at 30C.
Following completion of the addition the mixture was stirred
for two hours while the temperature was maintained at 60C.
15 ~ After the mixture had cooled to ambient temperature 400 cc.
of water were gradually added, followed by 1200 cc. of
methylene chloride. The organic layer was then separated,
dried using anhydrous magnesium sulfate and the methylene
chloride removed under reduced pressure. The residue was
passed through a column of neutral alumina using ethyl acetate
I .
as the eluent. The white solid obtained following removal
of the eluent and one recrystallization of the residue from
benzene weighed 90 g., melted between 114 and 117C. and
exhibited the following analysis. chlorine - 32.8%;
phosphorus - 9.89%. The calculated values for bis(p-chloro-
phenyl)chloromethylphosphine oxide are 33.3 and 9.70%,
respectively. The nuclear magnetic resonance spectrum was
consistent with the desired structure.
-5-
iOB4837
Example 3 - Bis(p-chlorophenyl)methylphosphlne
To 12.6 g. of magnesium turnings was gradually added
a solution containing 96 g. (0.50 mole) of p-chlorobromo-
benzene and 180 cc. tetrahydrofuran. The reaction mixture was
stirred and maintained under a nitrogen atomosphere during the
addition, following which the contents of the vessel were
heated to reflux temperature for two hours. When the reaction
mixture had cooled, a solution of methyldichlorophosphine
I (29.3 g., 0.25 mole) in 25 cc. tetrahydrofuran was gradually
added. Following completion of this addition the reaction
mixture was heated to reflux temperature for two hours. When
the mixture had cooled it was slowly poured into 500 cc. of
cold water and then acidified to a pH of 5 using aqueous hydro-
1 chloric acid. The resultant aqueous solution was extracted
1 using chloroform. The organic layer was then dried over
j anhydrous magnesium sulfate and the chloroform removed under
il reduced pressure. The residue remaining following removal Or
the chloroform weighed 64 g. and was distilled, the fraction
Ij boiling at between 155 and 160 under a pressure of 0.5 mm. Hg
1~ being collected. This distillate converted to a white solid
upor. cooling. The solid mâteriai weighed ~4 g. anà exhiDited
' the followlng analysls:
~¦ Found Calculated
Phosphorus 10.9% 11.5%
Chlorine 25.9% 26.4%
1084837
~xample 4 - Bis(p-chlorophenyl)propylphosphine Sulflde
Bis(p-chlorophenyl)propylphosphine was prepared by
reacting 0.2 mole of propyldichlorophosphine with 0.4 mole
of p-chlorophenylmagnesium bromide. The product was isolated
by chloroform extraction and distillation as previously
described. The portion boiling between 160 and 165~C. under
a pressure of 2 mm. Hg was collected. The analysis corresponded
to bis(p-chlorophenyl)propylphosphine.
¦ An 18 g. (0.061 mole) portion of the phosphine was
ji combined with 150 cc. benzene, followed by 2.1 g. (0.065 mole)
of sulfur. The resultant mixture was stirred for one hour
and the solvent removed under reduced pressure. Following
one recrystallization from diethyl ether the solld product
~ weighed 16 g. and melted between 102 and 107C. This product
1, was found to contain 9.21% phosphorus, 22.2% chlorine and
8.33~ sulfur. The calculated values ~or bis(p-chlGrophenyl)
propylphosphine sulfide are 9.42, 21.6 and 9.73%, respectively.
~j When employed to control insects and acarids the
Il present phosphines, phosphine oxides and phosphine sulfides
~ can be applied directly onto the insects, eggs~ infested plants
¦! cr to plants and other substrates -~hich are susceptible to
~, infestation by insects and acarids. The long term residual actl-
vity and low phytotoxicity that characterize the present toxicant
I makes it possibIe to apply these compounds to plants several days
¦ and in some inStanceS weeks, prior to the time when the plant
wlll be expo ed to 1nsects or acar:lds.
-7-
, . ~ . ,-~ 1,
t ,. ,
~. . . ' , ' . -.
~84837
The present compounds are conventlonally applled to
plants as a liquid spray, solid dust or a wettable powder.
Compositions suitable for spraying are usually -~
prepared by diluting liquid concentrates or wettable powders
containing between 10 and 90% of the active toxican~. To
avoid the expense of transporting formulations containing
large amounts of inert diluents, the final dilution is usually
performed at the location where the composition will be applied.
The concentration of toxicant in a spray for large scale
~ applications is between 10 and 1000 parts per million (ppm),
preferably between 100 and 500 parts per million.
Solid dust compositions, which are generally applied
over a relatively small area, contain between 1 and 50% by
, weight of active toxicant, preferably between 1 and 10%.
1I The concentration of toxicant required in a given
formulation will be dependent upon a number of parameters
.!1 i
including the method of application, i.e. whether at ground
level or from aircraft, the activity of the particular toxicant
~,l against a given insect or acarid and weather conditions in the
2Q l! are~ being treated~
In the preparation of dust compositions or wettable
powders, the present toxicants can be blended with many
commonly employed finely divlded solids, such as fuller's earth, ¦
I attapulgite, bentonite, pyrophyllite, vermiculite, diatomaceous
earth, talc, chalk, gypsum, wood flour, and the like. The
finely divided carrier is ground or mixed with the
lf)~4B~ '
toxicant or wetted with a dispersion of the toxicant in a
volatile liquid. Depending upon the proportions of ingredients,
these compositions can be employed as concentrates and sub-
sequently diluted witn additional solid carriers to obtain the
desired amount of active toxicant. Also, such concentrate
dust compositions can be incorporated in intimate admixture
¦ with surface active dispersing agents such as ionic or nonionic
emulsifying or dispersing agents to form spray concentrates.
I Such concentrates are readily dispersible in liquid carriers
1 to form spray compositions or liquid formulations containing
¦ the toxicants in any desired amount. The choice of surface
active agent and amount e.~ployed are determined by the ability
of the agent to facilitate the dispersing of the concentrate
Il in the liquid carrier to produce the desired liquid compos~tion. ¦
ii Suitable liquid carriers include water, methanol, ethanol,
¦l isopropanol, methyl ethyl ketone, acetone, methylene chloride,
¦, chlorobenzene, toluene, xylene, and petroleum distillates.
Among the preferred petroleum distillates are those boiling
I almost entirely under 205C. at atmospheric pressure and having
I a ~lash point above about 30C.
Alternatively, the toxicant may be compounded with . .
a suitable water-immiscible organic liquid and a surface
active dispersing agent to produce emulsifiable concentrates
which may be further diluted with water and oil to form spray
mixtures in the form of oil-ln-water emulsions. In such
compositions, the carrier comprises an aqueous emulslon, i.e. .r
I .
_9_
i
. ' ~ .
- . ~ '
1084837
a mixture of water-lmmisclble solvent, emulsifying agent and
water. Preferred dispersing agents which may be employed in
these compositions are oil soluble and include the condensation
j products of alkylene oxides with phenols and organic or
, inorganic acids, polyoxyethylene derivatives of sorbitan esters,
alkylarylsulfonates, complex ether alcohols, mahogany soaps
and the like. Suitable organic liquids to be employed in the
j' compositions include petroleum distillates, 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 of from about
l to about 20 percent by weight of the combined weight of the
dispersing agent and the active toxicant.
The following examples demonstrate the efficacy of
the present compounds as insecticides and ovicides. Formulations
were prepared by dissolving the compound to be tested in a mixture
of acetone and a liquid alkyl-aryl polyether alcohol type
surfactant (Triton~ X-155) and diluting the resultant composition
to the desired concentration using a water-acetone mixture
2~ su^h that the linal formulation contained lO~ acetone and lO
parts per million (ppm) of the surfactant.
il l
~ I
--10--
.: i.
; , ,
1084~37
Example 5
The activity of a given compound as a contact
acaricide against the two-spotted spider mite
(Tetranychus urticae) was determined by transferring adult and
nymph mites to the leaves of Sieva lima bean plants. Twenty
four hours following the transfer the leaves were either sprayed
with or dipped into the aforementioned formulation containing
200 ppm of the compound to be tested. If the compound was to be
evaluated as a systemic acaricide and ovicide 21 cc. of a
formulation containing 520 ppm of the active compound was poured
into the soil surrounding the infested plant.
Nine to twelve days following application of the
formulation the leaves of all plants were examined using a
microscope to determine the number of dead mites and eggs.
The following compounds were found to be effective
contact type acaricides at a concentration of 200 ppm, in that
they killed at least 70% of the adult mites, nymphs and/or
' eggs.
,' 11
'' 11 : .~ : ,
. .
: ' ~
1084837
bis(p-chlorophenyl)ethylphosphlne oxide
bis(p-chlorophenyl)ethylphosphlne
bis(p-chlorophenyl)methylphosphine oxde
bis(p-chlorophenyl)chloromethylphosphine oxide
bis(p-chlorophenyl)propylphosphine oxide:
bis(p-chlorophenyl)methylphosphine sulfide
bis(p-chlorophenyl.)methylphosphine
bis(p-chlorophenYl)n-propylphosphine
. bis(p-chlorophenyl)isopropylphosphine oxide
bis(p-chlorop~enYl)t-butylphosphine oxide
bis(p-bromophenyl)methylphosphine oxide
bis(p-fluorophenyl)methylphosphine oxide
The following compounds, which are structurally
related to the present acaricides, were ineffective in
I controlling spider mites or their eggs (l~ss than 30% of mites
or eggs killed) at a concentration of 200 ppm.
!i
diphenylmethylphosphine oxide
diphenylchloromethylphosphine oxide
bis(p-chlorophenyl)trichloromethylphosphine oxide
bis(m-chlorophenyl)methylphosphine oxide
tris(p-chlorophenyl)phosphine oxide
bis(p-chloro-m-nitrophenyl)methylphosphine oxide
bis(p-tolyl)methylphosphine oxide
bis(m,p-dichlorophenyl)methylphosphine oxide
bis(p-chlorophenyl)hydroxymethylphosphine oxide
bis(p-chloro-o-methylphenyl)methylphosphine oxide
Two of the most effect~ve acaricides, bis(p-chloro- !
phenyl)methylphosphinè oxide (A) and bis(p-chlorophenyl)
chloromethylphosphine oxide (B) were evaluated further to
: ascertain the lowest concentration at which these compounds
are effective. The data from this test are summarized in the
!
: following table, together with the results obtained using
I` .
,j N'(4-chloro-o-tolyl)N,N-dimethylformamidine (Galecron~), a .
~I commercially accepted miticide and ovicide. All plants were
; rated twelve days after being sprayed with the test formulation.
,
1084837
COMPOUND CONCENTRATION % CONTROL OFNO. OF
(PPM)ADULT MITES DEAD EGGS
A 400 100 525
100 68 545
B 4005 103 605
100 90 670
94
Galecron~ (control) 400 65 135
ll 100 0
0
A formulation containing 100 ppm of bis(p-chloro-
phenyl)chlorom~thylphosphine oxide was poured onto the soil
surrounding the roots of a Sieva lima bean plant which was
infested with spider mites and eggs. Six days later 97% of
the adult mites and 90% of the eggs were dead on one leaf.
Examination of a second leaf revealed that 100% of the eggs
had been killed.
Example 6
This example demonstrates the efficacy of
bis(p-chlorophenyl)methylphosphine oxide as an insecticide
and ovicide for the Mexican bean beetle.
Newly hatched Mexican bean beetles were confined
' in a cage for two days together with a number of untreated
bean plants. On the thlrd day the beetles were classified
`
according to sex. Seven emale and five male beetles were
confined in a cage together with six bean plants which had
been previously treated with an aqueous dispersion of the
il
~ test compound. The dispersion was prepared by dissolving
the requlr-d amount of com~ound ln a small amount of aoetone
~ -13-
I!
1~ '
: . :`~ -` . . . .
. . .
~013~37
together with 1000 parts per million (ppm) of a nonionlc
sur~actant, an alkyl aryl polyether alcohol available as
~riton~ X-155 from the Rohm and Haas Company. The amount of
acetone employed was calculated such that the final dispersion
obtained following addition of the required amount of water
contained 100 ppm of the surfactant. The resultant dispersion
I containing a specified concentration of the test compound was
,i sprayed onto the leaves of the bean plants ~ust prior to
1~ introduction of the beetles. Two days following this introductior
~ a mortality count was taken. On the following day any egg
clusters present were collected and six untreated plants were
placed in the cage togethe~ with the beetles. The egg clusters,
together with the area of the leaf on which they resided, were
~ removed and placed in a petri dish which remained for five days
1i in an incubator maintained at a temperature of 78C. and a
;~ relative humidity of 90%. Egg clusters were also collected on
i the next two days from both the treated and untreated plants.
I Following removal from the incubator the egg clusters were placed
~1 ln transparent containers together with untreated bean plant
,¦ leaves. The percentage of eggs from each cluster which produced
I! larvae W5 q observed and recorded. Any larvae which emerged
¦I were transferred to untreated bean plants for observation.
¦ The compounds tested were bis(p-chlorophenyl)methyl-
I phosphine oxide (A) and bis(p-chlorophenyl)chloromethylphosphlne
11 oxide (B). While neither compound killed adult Mexican bean
beetles, both compounds are effective ovicides, as demonstrated
-14-
;,
1084837
by the data ln the accompanying table. Only a small fractlon
of the eggs matured into larvae. The number of egg clusters
deposlted was significantly reduced relative to beetles whlch
fed on only untreated leaves. The two compounds tested
exercise control by significantly reducing the second generation
population.
~i P bO ~
Ii ~ ~ ~ ~ ~% Eg~ Viability
~1 c~
! o ~ ^ o ~ o ~ ~
ol~ ¢ . ~ ~UntreatedTreated
~ o ~ ~ o ~ ~ Leaves Leaves
~ A 260 12 6 (untreated) 0,0,0,0,10,10
~, 6 (treated) 0,0,0,0,0,0
A 130 12 9 (untreated) 0,0,0,0,0,0,0,
3 (treated) 0,100 0,0,0
B 260 10 4 (untreated) 0,0,0,0
7 (treated) 0,0,0,0,0,75,50
B 130 12 3 (untreated3 0,0,50
5 (treated) 0,100,100,25,0 j
Control - 13 12 100
- Values given for each cluster evaluated.
Example 7
Four pair of adult Mexican bean beetles were allowed
to feed on untreated bean plants for several days and then
transferred to a cage containing bean plants which had pre~iously
, been sprayed to run-off with an aqueous dispersion contalning
25 i 260 ppm of either bis(p-chlorophenyl)isopropylphosphlne oxide
j or bis(p-chlorophenyl)t-butylphosphine oxide. All of
I the beetles were dead after feeding on the treated foliage.
11 '
!
-15-
~1 1
108~837
A control group of the same size which was feeding on untreated
plants exhibited no adverse effects.
¦ The dispersion employed to spray the bean plantB
was prepared :~ described ln the preceding Example 6.
" . . .
. . .
,
, . . .
.
.
-IG-
~ : ,, , , : . . -
~ ,, : : '
,: .
- :
