Note: Descriptions are shown in the official language in which they were submitted.
37~
- 1 - 73776-11
~ lerbicides such as 2,4-D, MCPA, MCPP, triclopyr,
clopyralid, picloram, benazolin, dicamba or mixtures of any two
or more of such herbicides are known~ Processes for making these
herbicides utilize aqueous or organic solvents which must be
separated from the reaction mixture in order to formulate the
desired herbicide product~ Separation of the solvents from the
reaction mixture after formation of the desired product requires
multiple steps and high energy requirements. It would be desir-
able to employ a process for preparing these herbicides which
eliminates using added solvents. It is also desirable to be able
to prepare the alkanolamine salts of these herbicides and ship
them in the dxy water-free condition to save on weight.
The present invention is directed to a method of pre-
paring a substantially water-free alkanolamine salt of herbicides,
preferably 2,4-D, MCPA, MCPP, triclopyr, clopyralid, picloram,
benazolin, dicamba, or a mixture of any two or more of such herbi-
cidal compounds which comprises
(a) warming gradually while stirring in the absence
of an added aqueous or organ:ic solvent medium a sub-
stantially equimolar mixture of one or more of said
herbicides and an alkanolamine; and continuing to
warm and stir the mixture until a paste or incipient
melt is formed;
(b) allowing the mixture to cool; and
(c) continuing to stir the mixture as it cools until a
free-flowing powder is obtained.
C
-
~3979~
- 2 - 73776-11
After preparation of the cooled powder from step (c),
the cooled powder may be optionally treated by
(d) dry blending the cooled powder with from about 0.2 to
about 2 percent by weight of an agriculturally accep-
table sequestrant; from about 0.5 to about 2 percent
by weight of an agriculturally acceptable surfactant
and from about 0.5 to about 2 percent by weight of an
anticaking agent.
According to another aspect of the present invention
there is provided the method of preparing substantially water-free
water-dispersible herbicidal product of a phenyl-, phenoxy- or
oxobenzothiazolyl 2-propanoic acid or acetic acid herbicide which
comprises:
(a) warming gradually while stirring, in the absence of a
solvent medium, a substantially stoichiometric mixture of one or
more of said herbicides and diethanolamine, said mixture having
added thereto from about 7 to about 15 percent by weight oE
ethanolamine based on the weight of diethanolamine employed; and
(b) continuing to warm and stir the mixture until a paste
or incipient melt is formed;
(c) allowing the mixture to cool;
(d) continuing to stir the mixture as it cools until a
free-flowing powder is obtained; and
(e) dry blending the cooled powder with from about 0.2 to
2 percent by weight of an agriculturally acceptable sequestrant,
from about 0.5 to about 2 percent by weight of an agriculturally
g~
- 2a - 73776-11
accep-table surfactant and from about 0.5 to about 2 percent by
weight of an anticaking agent.
The herbicide "2,4-D" refers to the compound known
as (2~4-dichlorophenoxy~ acetic acid, a white crystalline solid,
having a melting point o~ 135 to 138 Centigrade (C) (technical)
and 140 to 141 (pure).
The herbicide "MCPA" refers to the compound known
as metaxon or [(4-chloro-O-tolyl)oxy]acetic acid
~ ~ 3
--3--
which is a light brown solid having a melting point of
118~ to 119C (pure) or 99 to 107C (technical).
The herbicide "MCPP" refers to the compound
known as mecoprop or [2-(2-methyl-4-chlorophenoxy)--
propionic acid], which is a colorless crystalline solid
having a melting point of 94 to 95C.
The herbicide "triclopyr" refers to the
compound [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid
having a melting point of 148 to 150C.
The herbicide "clopyralid" refers to the
compound 3,6-dichloropicolinic acid or by code name
DOWCO 290, of The Dow Chemical Company, Midland,
Michigan. Clopyralid is a white, crystalline solid
having a melting point of 151 to 152C.
The herbicide "picloram" refers to the compound
4-amino-3,5,6-trichloropicolinic acid, a white powder
which decomposes before melting.
The herbicide "benazolin" refers to the
compound 4-chloro-2-oxobenzothiazolin-3-ylacetic acid,
which has a melting point of 189C.
The herbicide "dicamba" refers to the compound
3,6-dichloro-o-anisic acid, which is a white
crystalline solid (reference grade) or a brown
crystalline solid (technical acid) having a melting
point of 114 to 116C.
The term "alkanolamine" is intended to mean any
one or more of ethanolamine, diethanolamine,
triethanolamine, isopropanolamine, diisopropanolamine
or triisopropanolamine, which are capable of forming a
31,494-F -3-
~ 7
--4--
crystalline salt of any of` sa.id herbicides which is a
solid at room temperature.
The term "ethanol amine" (.MEA) refers to the
compound known as ~-aminoethanol or 2-hydroxyethylamine
having the formula HOCH2CH2NH2o
The term "diethanolamine" (DEA) refers to the
compound known as di(2-hydroxyethyl)amine having the
formula (HOCH2CH2)2NH.
The term "triethanolamine" (TEA) refers to the
compound known as tri(2-hydroxyethyl)amine having the
formula (HOCH2CH2)3N.
The term "isopropanolamine" (MIPA) refers to
the compound known as 2-hydroxypropylamine or 1-amino-
2-propanol) having the formula CH3CH(OH)CH2NH2.
The term "diisopropanolamine" (DIPA) refers to
the compound having the formula (CH3CHOHCH2)2NH.
The term "triisopropanolamine" refers to the
compound having the formula N(C3H60H)3.
The alkanolamines are known compounds and can
be prepared by reaction of ethyloxide and ammonium to
give a mixture of mono-, di-, and triethanolamines.
Where diethanolamine and ethanolamine are
jointly employed7 the proportions of diethanolamine to
ethanolamine in the alkanolamine mixture can range from
about 7 to about 15 percent by weight of ethanolamine,
based on the total weight of diethanolamine, more
preferably from about 7 to about 12 percent by weight
based on the weight of the diethanolamine employed.
31,494-F -4-
~ ~ 3 ~7
--5--
A preferred mixture of the alkanolamine is a
50:50 mixture by weight oP diethanolamine and
ethanolamine.
In preparing the substantially water-free
alkanolamine salt, quantities of the phenyl, phenoxy or
oxobenzothiazolyl alkanoic acid herbicide are warmed
gradually to a temperature at or below the melting
temperature of the herbicide. To the warmed herbicide,
a substantially~equimolar amount of an alkanolamine
described hereinbefore is added. The mixture of the
herbicide and alkanolamine is continuously warmed and
stirred until a paste or an incipient melt is formed.
Upon formation of the paste or incipient melt, the
mixture is allowed to cool, and the cooling mixture is
stirred until a free-flowing powder is obtained. In
general, the alkanolamine salts of the invention are
freely water soluble. This is clearly preferred.
The alkanolamine salts prepared according to
the invention have substantially the same herbicidal
properties as the alkanGlamine salts prepared in
aqueous or organic solvent reaction medium.
Optionally and preferably, sequestrants,
surfactants and anticaking agents can be further
admixed with the free-flowing powder to improve the
handling and/or herbicidal efficacy properties of said
herbicide compounds.
Agriculturally acceptable sequestrants include,
but are not limited to, ethylenediamine tetraacetic
acid, cLtric acid or a diglycolic acid. The amount of
sequestrant added to the free-flowing powder can range
31,494-F -5-
3~791
--6--
from about 0.2 to about 2 percent by weight of the
final herbicide product.
Agriculturally acceptable surfactants or
wetting agents include, but are not limited to, sodium9
mono- and dimethyl napthalene sulfonates. A preferred
surfactant is Petro-Ag Special U.F., product of Petro
Chemicals Corporation9 Fort Worth, Texas. The amount
of surfactant added to the free-flowing powder can
range from about 0.5 to about 2 percent by weight of
the final herbicide product.
Agriculturally acceptable anticaking agents
include, but are not limited to, fumed silica or
hydrated reprecipitated silica. A preferred anticaking
agent is Sipernat 22, trademark of the Degusson
Corporation, Teterboro, New Jersey. The amount of
anticaking agent addèd to the free-flowing powder can
range from about 0.5 to about 2 percent by weight of
the final herbicide product.
The sequestrants, surfactants and anticaking
agents can be dry blended to the cooled powder to form
the desired herbicide product.
The ~ollowing examples illustrate the present
invention and the manner by which it can be practiced
but, as such, should not be construed as limitations
upon the overall scope of the same.
Example l
On mixing 256.5 grams (g) (1.0 mole) of
triclopyr ancl 105 grams (1.0 mole) of diethanolamine, a
damp compressible powder was obtained. This mixture
was warmed and stirred simultaneously. The mixture
31,494-F -6-
~r~ 3~7~
~radually became paste-like and then, without ~orming a
true melt, started to thickenO Heating was stopped but
stirring was continuedO As the reaction mixture cooled
it turned into a free-flowing powder that was readily
soluble in water.
Example_2
A clear melt was made by gradually warming and
stirring 44.2 g (0.2 mole) of 2,4-D with 2100 g (0.2
mole) of diethanolamine. On cooling and stirring the
melt, the solid herbicide amine salt was obtained in
free-flowing powder form.
Example 3
In a sïmilar manner, as in Example 2, a free-
flowing powder was formed on reacting 24.1 g (0.10
mole) of picloram and 10.5 g (0.1 mole) of
diethanolamine salt.
Example 4
A dry mixture was prepared by grinding 10 g of
the 2,4-D amine salt as prepared in Example 2 and 2 g
of the picloram amine as prepared in Example 3 together
with a mortar and pestle until a uniform blend was
obtained. The dry mixture was free-~lowing and readily
water soluble. On applying an aqueous solution of the
ary mixture to broadleaf weedy plants at a herbicidally
effective rate, the expected spectrum of weedy planks
is controlled to the extent predicted from known uses
of the aeti~e ingredient amine salts separately
applied.
31,494-F -7-
-8
Example 5
A 44.2 g (0.2 mole) portion of 2,4-D and 21.0 g
(0.2 mole) of diethanolamine were reacted and made into
a free-flowing powder in the same manner as described
in Example 2.
Example 6
In a similar manner, as in Example 2, 43.0 g
(0.2 mole) of mecoprop was reacted with 21.0 g (0.2
mole) of diethanolamine, and 22.0 g (0.10 mole) of
dicamba was reacted with 10.5 g (0.10 mole) of
diethanolamine, in both cases forming a free-flowing
powder.
A dry mixture was then made by dry blending 26
g of the 2, 4-D salt, 13 g of t~e mecoprop salt and 2.5
g of the dicamba salt to form a useful, stable readily
water soluble herbicidal mixture. On applying an
aqueous solution of the three-component dry mixture to
broadleaf weedy plants at a herbicidally effective rate
the expected spectrum of weedy plants is controlled to
the extent predicted from known uses of the active
ingredient salts separately applied.
Example 7
Using the same procedures, as in Examples 2 and
5, 25.0 g of 3,6-dichloropicolinic acid were reacted
with 13.7 g (0.13 mole) of diethanolamine and 25.0 g
(0.10 mole) of benazolin were reacted with 10.8 g of
(0.10 mole) of diethanolamine to form free-flowing salt
powders. A 15 g portion of each salt powder was
thoroughly dry blended together to provide a useful,
stable, free-flowing freely water soluble herbicidal
31,494-F -8-
~ 3~3
_9_
mixture. On applying an aqueous solution of the two-
component mixture alone or with a small amount of
surfactant added to broadlea~ weedy plants at a
herbicidally effective rate, the expected spectrum of
weedy plants is controlled to the extent predicted from
known uses o.f the active ingredient salts separately
applied.
Example
A mixture of 14.0 g (0.06 mole) of picloram and
38.4 g (0.361 mole) of diethanolamine was warmed and
stirred together until complete reaction of the
picloram was shown by formation of a clear melt. Then
68.0 g (0.31 mole) of 2,4-D was added to the melt, and
the melt stirred as it cooled, forming a free-flowing
powder. The free-flowing powder was found to be
readily water soluble. The herbicidal properties of
the picloram and 2,4-D salts are substantially the same
as that of the diethanolamine salts made in other ways.
Example 9
A mixture of 32.0 g (0.14 mole) of 2,4-D,
1~.0 g (0.07 mole) of mecoprop, 3.0 g (0.01 mole) of
dicamba and 25.0 g (0.23 mole) of diethanolamine was
gradually warmed and stirred together sufficiently to
obtain a clear melt, then stirred while the melt cooled
and turned into a free flowing powder. The co-reacted
3 salts so-prepared are readily water soluble, and the
herbicidal properties are substantially not changed by
the method of making the salts. The mixture is a
useful herbicidal product that is conveniently and
economically handled and transported.
31,494-F -9-
~ o ~3~3'7~
Example 10
A mixture of 25.0 g (0.13 mole) of 3.6-
dichloropicolinic acid (clopyralid) 9 25.0 g of
benazolin (0.10 mole) and 24.5 g (0.23 mole) of
diethanolamine was gradually warmed and stirred
together sufficiently to obtain a clear melt, then
stirred while the melt cooled into lumps which readily
broke up on continued stirring to form a free-flowing
powder. The co-reacted salts so-prepared are readily
water soluble and the herbicidal properties are
substantially not changed by the method of making the
salts. The mixture is a useful herbicidal product that
is conveniently and economically handled and
transported.
Example 11
The diethanolamine salts of 2,4-D, mecoprop and
dicamba are prepared separately by reacting 32.0 g of
2,4-D, 16.0 g of mecoprop and 3.0 g of dicamba with
respective stoichiometric amounts of diethanolamine in
the manner described in`Example 1, each forming a free-
flowing powder. The so-obtained dry powders are
thoroughly dry-blended together to form a useful
herbicidal product that is readily water soluble.
The melting temperature of the blended powders
was determined along with that of the combination
3 products of Examples 2, 7, 8, 9 and 10. Each
combination product was passed through a 30 mesh sieve
(U.S. Sieve Series) and the underflow used for ease of
water solubility tests and pH determination of a 5
percent by weight aqueous solution of each combination
product. From the sieved material, in each case, 5 +
31,494-F -lO-
Z~3~
0.1 g of powder was measured out and placed in a lO0
milliliter (ml~ graduated cylinder. Deionized water
having a temperature of 22C9 and a pH of 6.7 was added
to each cylinder to bring the volume to 100 ml and the
cylinder stoppered. The cylinder, in each case, was
inverted manually each seco~d in a uniform manner.
After every six inversions, the contents of the
cylinder were inspected for undissolved solids and the
number of inversions required to obtain complete
solution of the solids noted. The pH of the resulting
solutions was determined with a conventional pH meter
equipped with a combination glass electrode.
3o
31,494-F -ll-
~2~3~7~
-12-
The results of the foregoing tests are summarized in
the following Table 1:
_able 1
PHYSICAL PROPERTIES OF COMBINATION SALT PRODUCTS
, . . . n_ _ __
Comblnation Product Tempera- ¦nver- pH of 5%
____ _ _
A. 2,4-D ~ picloram
_ _ . _ _ ._ . _ _
-Dry mixed salts 73.5 44 5.2
~ _ ~ . _
-Co-reacted salts 74.5 50 4.8
_~ _ . ..
B. 2,4 D ~ mecoprop
1 ~ . . , _ ~ .
, -Dry mixed salts57 to 74 26 5.1
. _. . . __
-Co-reacted salts59 to 71 38 4.9
_ ~ _ ,
C. Clopyralid~benazolin
~_ . . . . .
-Dry mixed salts 118 to 20 7.4
_
-Co-reacted salts 110 to 28 7.4
Example 12
A water jacketed blender was charged with
1875 g of 2,4-D acid, 891 g of diethanolamine and 30 g
of Petro-Ag Special U.F. wetting agent or surfactant
having a paste-like consistency and consisting of
sodium mono- and dimethyl napthalene sulfonates,
product of Petro Chemicals Corp., Fort Worth, Texas. A
heavy paste was formed on blending. The mixture was
heated by running 94C water through the jacket of` the
blender. After 14 minutes of heating and blending, the
31,494-F -12-
_13_ ~ 7~
mixture changed color, consistency and reaction to ~orm
the salt was judged to be complete.
Cooling was started by passing cold water
through the jacket of the blender as blending of the
paste was continued. After a solid was formed,
continued mixing broke the lumps initially formed into
a powder and 20 g of Sipernat 22 S~ (an absorptive
silica) trademark of the Degusson Corporation,
Teterboro, New Jersey, was added. About 38 percent of
the product passed a 16 mesh (U.S. Sieve Series) sieve
without resort to grinding. The sieved material
dissolved readily in water at ambient temperature as
shown by the fact 75 g of product dissolved in
sufficient water to yield 100 ml of solution.
Example 13
Upon heating and agitating together in a beaker
250 g of picloram and 584 g of diethanolamine, a clear
melt was obtained at a temperature of 70C. Meanwhile,
1000 g of 2,4-D and 20 g Petro Ag Special U.F. wetting
agent were placed in a water jacketed blender and pre-
mixed. The melt of reacted picloram and diethanolamine
was added to the premix in the blender, and hot water
was started through the jacket while blending was
carried out. After 8 minutes the mixture had become a
dark green melt with some lumpy material dispersed
therein. Cooling was started by running cold water
through the blender jacket while mixing continued.
After about l~ hours, the mixture had become a free-
flowing powder. Then 20 g of Sipernat 22 S absortive
silica was blended with the powder, and the resulting
mixture was sieved through a 16 mesh sieve, oversized
material being recycled for. lO minutes. A 75 percent
31,494-F -13-
-14~ 3~
fraction of the material passed through the sieve.
About 32 g of the ~sieved material was capable of
dissolving in sufficient water to form 100 ml of
solution.
Example 14
To a water jacketed blender was added 1400 g
MCPA and 20 g Petro Ag Special U.F., and the two mixed
while warm water was passed through the jacket. Then
426 g of monoethanolamine was added to the warmed
mixture. Reaction was complete in 6 minutes as mixing
continued, as shown by the formation of a melt. Cold
water was started through the blender jacket and mixing
was again continued. Within 20 minutes a free-flowing
powder had formed which was blended with 20 g of added
Sipernat 22 S silica. The powder product was subjected
to sieving through a 16 mesh sieve with recycling.
About 79 percent of the product passed the screen, and
60 g of the sieved material was capable of dissol~ing
in water at ambient temperature to form a 100 ml
solution.
Example 15
In an initial run, an alkanolamine salt of
2,4-D was prepared by warming and mixing 44.2 g (0.2
mole) of 2,4-D and 21.0 g (0.2 rnole) of diethanolarnine
together in an equimolar ratio in a water jacketed
3 blender. The paste initially formed turned into a melt
as warming and mixing continued. Cooling water was
then introduced into the jacket of the blender while
stirring was continued. The melt solidified into lumps
which rather readily broke up into a free-flowing
powder.
31,494-F -14-
_15- ~ 7
Example 16
In additional runs performed as in Example 15,
the same amount of 2,4-D was used in each run, but part
of the equimolar amount of diethanolamine was replaced,
on an equal weight basis, by monoethanolamine. The
extent of replacement varied from 2.5 to 20 percent
whereby the number of moles of alkanolamine also
varied. 274-D alkanolamine salt using the mixed
alkanolamines was carried out employing the method
described hereinabove for the diethanolamine salt.
Example 17
In the runs from Example 15 and 18, the melting
range of the free-flowing powder product was
determined. In addition in each case, 5 + 0.1 g of
powder was measured out and placed in a 100 milliliter
(ml) graduated cylinder. Deionized water having a
temperature of 22C and a pH of 6.7 was added to each
cylinder to bring the volume to 100 ml and the cylinder
stoppered. The cylinder, in each case, was inverted
manually each second in a uniform manner. After every'
six inversions, the contents of the cylinder were
inspected for undissolved solids, and the number of
inversions required to obtain complete solution of the
solids noted. The pH of the resulting solutions was
determined with a conventional pH meter equipped with a
combination glass electrode.
The results of the foregoing tests are
summarized in the following Table 2:
31,494-F -15-
~ ~3 ~ 7
-16
TABLE 2
Phvsical Properties of Combination Salt Products
. , ~ , ,,, .~ __ N
NUoOn Substituted Temperature to Solution
~ ~ ____________ __~ __,___
1 0 78.5 to 80.5 57 4.9
__ __ ~ ~ __
2 2.577 to 78.5 52 6.5
. ., ~ _~_ ~
3 576 to 77 48 7.3
4 7.573.5 to 75 29 7.8
1 0 _ . _ ...... . _
73 to 74O5 30 7.9
. ~ _._ _~
6 12.5 68 to 99 20 8.1
_ ~ _, ~ ~
7 5 67.5 to 103 ~ _8 B 2
8 20 66 to 108 5 8.4
_ _
Example 18
Using substantially the same procedure as set
forth in Example 15 for mixed alkanolamine salts except
that the amount of monoethanolamine substituted for
diethanolamine was fixed at 10 percent by weight, mixed
alkanolamine salts of 2,4-D and of picloram were
prepared, respectively. A mixture was prepared by
thoroughly blending together the two salts. The
mixture containecl 5 moles of the 2,4-D salt per mole of
the picloram salt.
Example l9
3o
The procedure of Example 15 was also repeated,
co-reacting a mixture of 2,4-D and picloram in a 5:1
molar ratio with a quantity of the mixed alkanolamine
which would have been equimolar if it had been all
diethanolamine. The alkanolamine mixture provided
about 7 mole percent more alkanolamine than the same
31,494-F -16-
~ 3 ~ 7
-17-
weight of diethanolamine provides~ The melting
temperature, ease of solubility and pH of a 5 percent
by weight aqueous solution of the dry blended mixture
and co-reacted mixture were determined in the same
manner as described in Example 15O The results are
summarized as follows:-
TABLE 3
Properties of Mixed Alkanolamine Salts
Run ilerbicide Meltin~ Inversions IPH of 5 lo
No. Combination Temp. C To Solution
Dissolve
_~ ~ ___
1 2,4-D + picloram 65 to 92 9 8.1
dry mixed
. . __ _ . _
2 2,4-D + picloram 58 to 90 20 8.1
co-reacted
_ . ~
31,494-F -17-
