U.S. patent application number 14/955147 was filed with the patent office on 2017-06-01 for novel form of tribenuron-methyl, a process for its preparation and use of the same.
This patent application is currently assigned to ROTAM AGROCHEM INTERNATIONAL COMPANY LIMITED. The applicant listed for this patent is ROTAM AGROCHEM INTERNATIONAL COMPANY LIMITED. Invention is credited to James Timothy BRISTOW.
Application Number | 20170152235 14/955147 |
Document ID | / |
Family ID | 58643430 |
Filed Date | 2017-06-01 |
United States Patent
Application |
20170152235 |
Kind Code |
A1 |
BRISTOW; James Timothy |
June 1, 2017 |
NOVEL FORM OF TRIBENURON-METHYL, A PROCESS FOR ITS PREPARATION AND
USE OF THE SAME
Abstract
A crystalline form of tribenuron-methyl of formula (I), the
crystal preparation process, the analyses of the crystal through
various analytical methods and using the crystal to prepare stable
agrochemical formulation. The invention also describes the use of
various solvents towards the crystalline form preparation
conditions. ##STR00001##
Inventors: |
BRISTOW; James Timothy;
(Chai Wan, HK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROTAM AGROCHEM INTERNATIONAL COMPANY LIMITED |
Chai Wan |
|
HK |
|
|
Assignee: |
ROTAM AGROCHEM INTERNATIONAL
COMPANY LIMITED
Chai Wan
HK
|
Family ID: |
58643430 |
Appl. No.: |
14/955147 |
Filed: |
December 1, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A01N 25/12 20130101;
A01N 47/36 20130101; C07D 251/16 20130101; A01N 25/14 20130101;
A01N 47/36 20130101; A01N 47/36 20130101; A01N 47/36 20130101; A01N
25/12 20130101 |
International
Class: |
C07D 251/16 20060101
C07D251/16; A01N 47/36 20060101 A01N047/36 |
Claims
1. A crystalline modification I of (methyl
2-[4-methoxy-6-methyl-1,3,5-triazin-2-yl(methyl)carbamoyl
sulfamoyl]benzoate) (Tribenuron-methyl) exhibiting each of the
following reflexes as 2.theta. values in X-ray powder diffractogram
recorded using Cu--K.alpha. radiation at 25.degree. C.:
2.theta.=6.47.+-.0.2 (1) 2.theta.=10.46.+-.0.2 (2)
2.theta.=11.02.+-.0.2 (3) 2.theta.=14.01.+-.0.2 (4)
2.theta.=15.73.+-.0.2 (5) 2.theta.=16.71.+-.0.2 (6)
2.theta.=16.98.+-.0.2 (7) 2.theta.=21.04.+-.0.2 (8)
2.theta.=22.23.+-.0.2 (9) 2.theta.=23.26.+-.0.2 (10)
2.theta.=25.01.+-.0.2 (11) 2.theta.=26.14.+-.0.2 (12).
2. (canceled)
3. (canceled)
4. (canceled)
5. The crystalline modification I of tribenuron-methyl according to
claim 1, exhibiting an IR spectrum with the characteristic bands at
one or more of 2957.46, 2160.18, 2032.70, 1728.01, and 1552.05
cm.sup.-1.
6. The crystalline modification I of tribenuron-methyl according to
claim 1, exhibiting a Differential Scanning calorimeter (DSC)
thermogram having an endothermic melting peak with onset at
132.3.degree. C. and peak maximum at 139.4.degree. C.
7. A process of preparing the crystalline modification I of
tribenuron-methyl according to claim 1, comprising: i) dissolving
an amorphous tribenuron-methyl into a solvent; ii) precipitating
the dissolved compound into the crystalline modification I of
tribenuron-methyl; and iii) isolating the precipitated crystalline
modification I.
8. The process according to claim 7, wherein the solvent is
methanol, ethanol, or a mixture thereof
9. (canceled)
10. (canceled)
11. The process according to claim 7, wherein step ii) comprises
concentrating the solvent, or cooling the dissolved compound and
solvent to ambient temperature, or to a temperature of around
0.degree. C. to 20.degree. C., or adding seed crystals of the
crystalline modification I, or a combination of these.
12. A crystalline modification I of tribenuron-methyl obtained
according to the process of claim 7, and wherein crystalline
modification I of tribenuron-methyl has a purity of at least 98% by
weight.
13. A composition comprising an herbicidally effective amount of
the crystalline modification I of tribenuron-methyl according to
claim 1, and at least one herbicidally acceptable auxiliary.
14. The composition according to claim 13, wherein the auxiliary is
selected from the group consisting of one or more of a surfactant,
a diluent, a wetting agent, a dispersant, a thickening agent and an
antifoaming agent.
15. The composition according to claim 13, wherein the crystalline
modification I of tribenuron-methyl is incorporated into the form
of a suspension concentrate (SC), an oil-based suspension
concentrate (OD), a water-soluble granule (SG), a dispersible
concentrate (DC), an emulsifiable concentrate (EC), an emulsion
seed dressing, a suspension seed dressing, a granule (GR), a
microgranule (MG), a suspoemulsion (SE) or a water-dispersible
granule (WG).
16. The composition according to claim 15, wherein the crystalline
modification I of tribenuron-methyl is incorporated into the form
of an oil-based suspension concentrate (OD), a water-dispersible
granule (WG) or a water-soluble granule (SG).
17. A method for controlling unwanted plant growth, comprising
applying to the plant, plant part, or surroundings of the plant, a
herbicidally effective amount of crystalline modification I of
tribenuron-methyl according to claim 1.
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
Description
BACKGROUND
[0001] Field
[0002] The present disclosure relates to a crystalline form of
(methyl
2-[4-methoxy-6-methyl-1,3,5-triazin-2-yl(methyl)carbamoylsulfamoyl]benzoa-
te) (tribenuron-methyl), to its preparation processes and to its
use in agrochemical preparations.
[0003] Description of Related Art
[0004] Tribenuron-methyl (methyl
2-[4-methoxy-6-methyl-1,3,5-triazin-2-yl(methyl)carbamoylsulfamoyl]benzoa-
te) is a member of the sulfonylurea group of chemicals and used as
herbicide. Tribenuron-methyl is a selective post-emergence
sulfonylurea herbicide for the control of broadleaved weeds on
crops, such as cereals and sunflower. Like other sulfonylureas, the
mode of action is via inhibition of the enzyme acetolactate
synthase (ALS), and thus prevention of the biosynthesis of the
essential amino acids isoleucine and valine.
[0005] Tribenuron-methyl has molecular formula of
C.sub.15H.sub.17N.sub.5O.sub.6S. Its chemical structure is
##STR00002##
SUMMARY
[0006] The commercially available tribenuron-methyl, which is
usually manufactured by the process described in EP 0202830, which
is incorporated herein by reference for all purposes, is present in
an amorphous state. It has been found that tribenuron-methyl in
amorphous state is highly viscous, which is not suitable for being
prepared as compositions or formulations that can be readily
cleaned out of spray equipment. Tribenuron-methyl residues remain
in the spray equipment after spraying. Adequate cleanout prior to
reuse of the spray equipment will typically require a rinsing
procedure that is not only time-consuming but also results in
wastewater disposal problems. Therefore, there is a need to provide
a novel form of tribenuron-methyl with increased solubility and
decreased viscosity. Accordingly, an embodiment of the invention
provides a novel crystalline form of tribenuron-methyl, termed
"crystalline modification I", and a process for its preparation, as
well as agrochemical compositions containing it, and methods for
using it in agrochemical applications, such as methods for applying
it to plants, plant parts and surroundings. The novel crystalline
modification I has been advantageously found to have increased
solubility, decreased viscosity, and improved spray equipment
clean-out properties.
[0007] Accordingly, an embodiment of the invention also provides
compositions for controlling the growth of undesirable plants, such
as weeds, comprising the crystalline modification I of
tribenuron-methyl on its own, as a mixture with auxiliaries and
carriers, and as a mixture with other active compounds. The use of
the crystalline modification I of tribenuron-methyl in the control
of undesired plant growth and a method for the same are also
provided by an embodiment of the invention.
BRIEF DESCRIPTION OF DRAWINGS
[0008] Various features and aspects of the embodiments of the
invention disclosed herein can be more clearly understood by
reference to the drawings, which are intended to exemplify and
illustrate, but not to limit, the scope of the invention, and
wherein:
[0009] FIG. 1 is an infrared (IR) spectrum of an embodiment of
crystalline modification I of tribenuron-methyl;
[0010] FIG. 2 is a X-ray powder diffractogram of an embodiment of
crystalline modification I of tribenuron-methyl;
[0011] FIG. 3 is a Differential Scanning calorimetry (DSC)
thermogram of an embodiment of crystalline modification I of
tribenuron-methyl; and
[0012] FIG. 4 is a powder X-ray diffractogram of amorphous
tribenuron-methyl.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0013] The invention can be more clearly understood by reference to
the following detailed description of specific embodiments thereof,
which is intended to illustrate, but not limit, the scope of the
appended claims.
[0014] It has been found that the crystalline modification I of
tribenuron-methyl has a significant increase in its solubility and
a significant decrease in its viscosity, which significantly
reduces the residue contamination and improves spray equipment
clean-out properties. In addition, it is found that the crystalline
modification I of tribenuron-methyl is easier to comminute or grind
compared to amorphous tribenuron-methyl prepared in accordance with
the disclosure of EP 0202830. This allows the preparation of
commercial formulations such as suspension concentrates (SC),
oil-based suspension concentrates (OD), water-dispersible granules
(WG) and water-soluble granules (SG). Hence, it is possible to
prepare any formulations of tribenuron-methyl in crystalline
modification I, which is disclosed hereinafter.
[0015] By virtue of its high solubility and low viscosity, the
crystalline modification I of tribenuron-methyl is highly suitable
for preparing compositions for controlling undesirable weeds.
[0016] According to a first aspect of the invention, a crystalline
modification I of tribenuron-methyl is provided, exhibiting at
least three of the following reflexes, in any combination, as
2.theta. values in an X-ray powder diffractogram recorded using
Cu--K.alpha. radiation at 25.degree. C.:
2.theta.=6.47.+-.0.2 (1)
2.theta.=10.46.+-.0.2 (2)
2.theta.=11.02.+-.0.2 (3)
2.theta.=14.01.+-.0.2 (4)
2.theta.=15.73.+-.0.2 (5)
2.theta.=16.71.+-.0.2 (6)
2.theta.=16.98.+-.0.2 (7)
2.theta.=21.04.+-.0.2 (8)
2.theta.=22.23.+-.0.2 (9)
2.theta.=23.26.+-.0.2 (10)
2.theta.=25.01.+-.0.2 (11)
2.theta.=26.14.+-.0.2 (12)
[0017] The crystalline modification I of tribenuron-methyl of an
embodiment of the invention is characterized by an X-ray powder
diffractogram having at least three of the reflexes indicated
above, in any combination thereof. Preferably, the crystalline
modification I is one having at least four of the aforementioned
reflexes, more preferably at least five six or seven, or eight of
said reflexes, again in any combination thereof. An X-ray powder
diffractogram of the crystalline modification I of
tribenuron-methyl is shown in FIG. 2, which will be described in
detail hereinafter.
[0018] According to a preferred embodiment the crystalline
modification I exhibits at least 3, 4, or 5 or all of the reflexes,
in any combination, from the following:
2.theta.=10.46.+-.0.2 (2)
2.theta.=11.02.+-.0.2 (3)
2.theta.=14.01.+-.0.2 (4)
2.theta.=15.73.+-.0.2 (5)
2.theta.=16.71.+-.0.2 (6)
2.theta.=21.04.+-.0.2 (8)
2.theta.=23.26.+-.0.2 (10)
2.theta.=25.01.+-.0.2 (11)
[0019] The X-ray powder diffractogram was taken using a
diffractometer from in reflection geometry in the range from
3.degree.-60.degree. with increments of 0.03.degree. using
Cu-K.alpha. radiation at 25.degree. C. The crystalline modification
I of tribenuron-methyl according to an embodiment of the invention
may be further characterized by Infrared (IR) spectroscopy. The IR
spectrum was measured with the resolution of 4 cm.sup.-1 and with
the number of scans of 16 for the purified sample. The IR spectrum
of crystalline modification I of tribenuron-methyl can be
identified by its characteristic functional group vibrations
(characteristic bands) at one or more of 2957.46, 2160.18, 2032.70,
1728.01 and 1552.05cm.sup.-1 as shown in FIG. 1.
[0020] All IR spectra were obtained using the following acquisition
parameters:
TABLE-US-00001 FT-IR spectrometer Bruker Tensor37 Diamond ATR unit
from Specac Wavelength range 550-4000 cm.sup.-1 Resolution 4
cm.sup.-1 Number of scans 16
[0021] The crystalline modification I of tribenuron-methyl
according to an embodiment of the invention may be further
characterized by Differential Scanning calorimetry (DSC) (FIG. 3).
An endothermic melting peak with onset at 132.3.degree. C. and peak
maximum at 139.4.degree. C. is shown in FIG. 3.
[0022] Methods for preparing amorphous tribenuron-methyl are known
in the art. Amorphous tribenuron-methyl is manufactured and
available on a commercial scale. A particularly suitable method for
preparing amorphous tribenuron-methyl is described in EP
0202830.
[0023] According to an embodiment of the invention, the crystalline
modification I of tribenuron-methyl can be obtained by the
processes below:
[0024] Tribenuron-methyl in the amorphous state is dissolved and
then crystallized from a solvent.
[0025] In one aspect, the present invention provides a process for
preparing a crystalline modification I of tribenuron-methyl
comprising steps of: [0026] i) dissolving an amorphous
tribenuron-methyl in a solvent; [0027] ii) precipitating the
dissolved compound into crystalline modification I of
tribenuron-methyl of formula I; and [0028] iii) isolating the
precipitated crystalline modification I.
[0029] Suitable solvents for preparing tribenuron-methyl
crystalline modification I include halogenated hydrocarbons (for
example, chlorobenzene, bromobenzene, dichlorobenzene,
chlorotoluene and trichlorobenzene), ethers (for example, ethyl
propyl ether, n-butyl ether, anisole, phenetole, cyclohexyl methyl
ether, dimethyl glycol, diphenyl ether, dipropyl ether, diisopropyl
ether, di-n-butyl ether, diisobutyl ether, diisoamyl ether,
ethylene glycol dimethyl ether, isopropyl ethyl ether, methyl
tert-butyl ether, tetrahydrofuran, methyltetrahydrofuran, dioxane,
dichlorodiethyl ether, methyl-tetrahydrofuran, polyethers of
ethylene oxide and/or propylene oxide), nitrated hydrocarbons (for
example, nitromethane, nitroethane, nitropropane, nitrobenzene,
chloronitrobenzene and o-nitrotoluene), aliphatic, cycloaliphatic
or aromatic hydrocarbons (for example, pentane, n-hexane,
n-heptane, n-octane, nonane), cymene, petroleum fractions within a
boiling range of from 70.degree. C. to 190.degree. C., cyclohexane,
methylcyclohexane, petroleum ether, ligroin, octane, benzene,
toluene and xylene), esters (for example, malonates, acetic acid
n-butyl ester (n-butyl acetate), methyl acetate, ethyl acetate,
isobutyl acetate, dimethyl carbonate, diethyl carbonate, dibutyl
carbonate and ethylene carbonate), and aliphatic alcohols (for
example, methanol, ethanol, n-propanol, isopropanol, n-butanol and
tert-amyl alcohol), and mixtures of these.
[0030] Preferred solvents include alcohols aromatic hydrocarbons
(such as benzene, toluene, xylene, chlorobenzene), esters and
aliphatic alcohols, and mixtures thereof. Particularly preferred
solvents or solvent mixtures include isopropanol, toluene,
methyl-tetrahydrofuran, diethyl carbonate, chlorobenzene, n-butyl
acetate, isobutyl acetate, n-butanol, methanol, ethanol, ethyl
malonate, methyl t-butyl ether, and mixtures of toluene and
butanol, mixtures of toluene and n-butyl acetate, mixtures of ethyl
malonate and methyl t-butyl ether, as well as mixtures of butyl
acetate and methyl t-butyl ether. Solvent mixtures of more than 2
or 3 or 4 components are also envisaged by embodiments of the
invention.
[0031] In an embodiment of the invention, it is preferred that the
solvent comprises at least one alcohol, and more preferably
comprises at least one straight or branched C1-C8 aliphatic
alcohol, more preferably at least one straight or branched C1-C4
aliphatic alcohol, even more preferably at least one of methanol
and ethanol.
[0032] According to another preferred embodiment, the solvent
essentially consists of an alcohol as mentioned above or mixtures
thereof.
[0033] Hence, according to a preferred embodiment in step (i),
amorphous tribenuron-methyl is dissolved in a solvent comprising an
alcohol. In a preferred embodiment, the solvent essentially
consists of methanol and/or ethanol.
[0034] According to a preferred embodiment in step (i), amorphous
tribenuron-methyl is dissolved in a solvent or a solvent mixture as
a concentrated solution by heating from room temperature or ambient
temperature to reflux temperature or below the reflux temperature
of the solvent or the solvent mixture. Preferably, the concentrated
solutions can be prepared at the reflux temperature of the
solvents. The concentration of the solution depends on the
solubility of tribenuron-methyl in the corresponding solvent or
solvent mixture.
[0035] The concentrated homogeneous solution thus prepared as in
step (i) is then cooled to room or ambient temperature, or to a
temperature of around 0.degree. C. to 20.degree. C. to crystallize
the desired crystalline form from the solvent. The crystalline
modification I of tribenuron-methyl can also be crystallized out by
concentrating the homogeneous solution through removing the solvent
or solvent mixture to a certain volume either with or without
applying vacuum and cooling to below the reflux temperature of the
solvent or the solvent mixture.
[0036] Alternatively, or in addition thereto, crystalline
modification I of tribenuron-methyl can also be effected by adding
seed crystals of the desired crystalline form during
crystallization into a solution prepared in step (i), which can
promote and/or accelerate the crystallization.
[0037] The seed crystal amount added to the concentrated solution
is typically in the range of 0.001 to 10% by weight,
preferably0.001 to 2.5 wt %, often 0.005 to 0.5% by weight based on
the weight of tribenuron-methyl used for the preparation of
concentrated solution in step (i). Preferably, the seed crystals
are added to the concentrated solution at the temperature below the
boiling point of the corresponding solvent or the solvent
mixture.
[0038] Hence, the precipitation of the crystalline modification I
of tribenuron-methyl can be effectively achieved from the
concentrated solution by a person of ordinary skill in the art.
[0039] The precipitated crystalline modification I of
tribenuron-methyl obtained from step (ii) is isolated by the usual
solid component separating techniques from solutions, such as
filtration, centrifugation or decantation. Then, the isolated solid
precipitate is washed with solvent one or more times. Preferably,
the solvent employed in the washing stage consists of one or more
components of the solvent or solvent mixture employed for
preparation of concentrated solution in step (i), as described
hereinbefore. The washing is usually carried out using the
corresponding solvent or solvent mixture between room temperature
and 0.degree. C., depending on the solubility of the crystal, in
order to minimize or avoid the loss of crystalline material in the
corresponding washing solvent as much as possible.
[0040] The invention, in an embodiment, also relates to a
composition comprising the crystalline modification I of
tribenuron-methyl. The amount of the crystalline modification I of
tribenuron-methyl is less than 75% by weight of the composition,
preferably less than 50% by weight of the composition, more
preferably less than 30% by weight of the composition, still more
preferably about 25% by weight of the composition.
[0041] The use of amorphous tribenuron-methyl as a herbicide is
known in the art and is used on a commercial scale. The crystalline
modification I of tribenuron-methyl is also active in controlling
unwanted plant growth, such as weeds. Techniques of formulating and
applying amorphous tribenuron-methyl are known in the art, for
example as disclosed in the documents described hereinbefore.
Tribenuron-methyl in the crystalline modification I of the present
invention may be formulated and applied in manner analogous to
those described for amorphous tribenuron-methyl.
[0042] Accordingly, in a further aspect, an embodiment of the
invention provides a herbicidal composition comprising
tribenuron-methyl in the crystalline modification I as defined
hereinbefore.
[0043] Accordingly, an embodiment of the invention furthermore
provides processes for preparing compositions for controlling
unwanted plant growth using the crystalline modification I of
tribenuron-methyl.
[0044] Accordingly, the invention also provides a method for
controlling unwanted plant growth, comprising applying to the
plant, plant part, or surroundings, a herbicidally effective amount
of crystalline modification I of tribenuron-methyl.
[0045] The crystalline modification I of tribenuron-methyl can be
incorporated into the customary formulations, such as suspension
concentrates (SC), oil-based suspension concentrates (OD),
water-soluble granules (SG), dispersible concentrates (DC),
emulsifiable concentrates (EC), emulsion seed dressings, suspension
seed dressings, granules (GR), microgranules (MG), suspoemulsions
(SE) and water-dispersible granules (WG) using suitable
auxiliaries, carriers and solvents, in a manner analogous to that
known for amorphous tribenuron-methyl.
[0046] In this context, the crystalline modification I of
tribenuron-methyl should be present in a concentration of from
about 0.1 to about 75% by weight of the total mixture, i.e., in
amounts sufficient to achieve the required dosage. The formulations
are prepared, for example, by extending the crystalline
modification I of tribenuron-methyl with water, solvents and
carriers, using, if appropriate, emulsifiers and/or dispersants,
and/or other auxiliaries.
[0047] These formulations are prepared by mixing the crystalline
modification I of tribenuron-methyl with an effective amount of at
least one acceptable auxiliaries, for example, surfactants, liquid
diluents, solid diluents, wetting agents, dispersants, thickening
agent, antifoaming agent and other formulation ingredients.
[0048] Liquid diluents include, but are not limited to, water,
N,N-dimethylmamide, dimethyl sulfoxide, N-alkylpyrrolidone,
ethylene glycol, polypropylene glycol, propylene carbonate, dibasic
esters, paraffines, alkylbenzenes, alkyl naphthalenes, glycerine,
triacetine, oils of olive, castor, linseed, sesame, corn, peanut,
cotton-seed, soybean, rape-seed and coconut, ketones such as
cyclohexanone, 2-heptanone, isophorone and
4-hydroxy-4-methyl-2-pentanone, acetates such as hexyl acetate,
heptyl acetate and octyl acetate, and alcohols such methanol,
cyclohexanol, decanol, benzyl and tetrahydrofurfuryl alcohol, and
mixtures thereof.
[0049] Solid diluents can be water-soluble or water-insoluble.
Water-soluble solid diluents include, but are not limited to, salts
such as alkali metal phosphates (e.g., sodium dihydrogen
phosphate), alkaline earth phosphates, sulfates of sodium,
potassium, magnesium and zinc, sodium and potassium chloride,
sodium acetate, sodium carbonate and sodium benzoate, and sugars
and sugar derivatives such as sorbitol, lactose, sucrose and
mannitol. Examples of water-insoluble solid diluents include, but
are not limited to clays, synthetic and diatomaceous silicas,
calcium and magnesium silicates, titanium dioxide, aluminium,
calcium and zinc oxide, and mixtures thereof.
[0050] Wetting agents include, but are not limited to, alkyl
sulfosuccinates, laureates, alkyl sulfates, phosphate esters,
acetylenic diols, ethoxyfluorinated alcohols, ethoxylated
silicones, alkyl phenol ethoxylates, benzene sulfonates,
alkyl-substituted benzene sulfonates, alkyl a-olefin sulfonates,
naphthalene sulfonates, alkyl-substituted napthalene sulfonates,
condensates of naphthalene sulfonates and alkyl-substituted
naphthalene sulfonates with formaldehyde, and alcohol ethoxylates,
and mixtures thereof. Alkyl naphthalene sulphonates, sodium salts
are particularly useful for the composition of the invention
[0051] Dispersants include, but are not limited to, sodium, calcium
and ammonium salts of ligninsulfonates (optionally
polyethoxylated); sodium and ammonium salts of maleic anhydride
copolymers; sodium salts of condensed phenolsulfonic acid; and
naphthalene sulfonate-formaldehyde condensates, and mixtures
thereof. Ligninsulfonates such as sodium ligninsulfonates are
particularly useful for the composition of the invention.
Naphthalene sulfonate-formaldehyde condensates such as
naphthalenesulfonic acid, polymers with formaldehyde, and sodium
salts are particularly useful for the composition of the
invention
[0052] Thickening agents include, but are not limited to, guar gum,
pectin, casein, carrageenan, xanthan gum, alginates,
methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and
carboxymethylcellulose, and mixtures thereof. Synthetic
thickeningagents include derivatives of the former categories, and
also polyvinyl alcohols, polyacrylamides, polyvinylpyrrolidones,
various polyethers, their copolymers as well as polyacrylic acids
and their salts, and mixtures thereof. Alkylpolyvinylpyrrolidones
are particularly useful for the composition of the invention
[0053] Other formulation ingredients can also be used in the
present invention such as dyes, drying agents, and the like. These
ingredients are known to one skilled in the art.
[0054] The crystalline modification I of tribenuron-methyl
according to an embodiment of the invention can be present in
formulations and in its use forms, prepared from these
formulations, and as a mixture with one or more other active
compounds (such as insecticides, attractants, sterilizing agents,
bactericides, acaricides, nematicides, fungicides,
growth-regulating substances, herbicides, safeners, fertilizers and
semiochemicals) or with agents for improving plant properties.
[0055] When used as a herbicide, the crystalline modification I of
tribenuron-methyl according to an embodiment of the invention can
furthermore be present in formulations and its use forms, prepared
from these formulations, and as a mixture with inhibitors which
reduce degradation of the active compounds after their use in the
environment of the plant, on the surface of plant parts or in plant
tissues.
[0056] All plants, plant parts, and their surroundings can be
treated in accordance with the invention. In the present context,
plants are to be understood as meaning all plants and plant
populations such as desired and undesired wild plants or crop
plants (including naturally occurring crop plants). Crop plants can
be plants which can be obtained by conventional breeding and
optimization methods, by biotechnological and genetic engineering
methods, or by combinations of these methods, including the
transgenic plants and the plant cultivars which can or cannot be
protected by plant breeders' rights. Plant parts are to be
understood as meaning all parts and organs of plants above and
below the ground, such as shoot, leaves, needles, stalks, stems,
flowers, fruit bodies, fruits, seeds, roots, tubers and rhizomes.
Harvested materials, and vegetative and generative propagation
materials, for example, cutting, tubers, meristem tissue, rhizomes,
offsets, seeds, single and multiple plant cells and any other plant
tissues, are also included.
[0057] As used herein, the term "about," when used in connection
with a numerical amount or range, means somewhat more or somewhat
less than the stated numerical amount or range, to a deviation of
.+-.10% of the stated numerical amount or endpoint of the
range.
[0058] "Surrounding," as used herein, refers to the place on which
the plants are growing, the place on which the plant propagation
materials of the plants are sown, the place on which the plant
propagation materials of the plants will be sown or the environment
near the plants.
[0059] The term "herbicidally effective amount" as used herein,
refers to the quantity of such a compound or combination of such
compounds that is capable of producing a controlling effect on the
growth of plants. The controlling effects include all deviation
from the natural development of the target plants, for example
killing, retardation of one or more aspects of the development and
growth of the plant, leaf burn, albinism, dwarfing and the
like.
[0060] Treatment according to an embodiment of the invention of the
plants, plant parts, and/or their surroundings, with the
compositions or formulations of the invention is carried out
directly or by allowing the compositions or formulations to act on
their surroundings, habitat or storage space by the customary
treatment methods. Examples of these customary treatment methods
include dipping, spraying, vaporizing, fogging, broadcasting,
painting on in the case of propagation material, and applying one
or more coats particularly in the case of seed.
[0061] The benefits of the invention are seen most when the
herbicidal composition is applied to kill weeds in growing crops of
useful plants: such as maize (corn) including field corns, pop
corns and sweet corns, cotton, sunflower, cereal, barley, wheat,
rice, oats, potatoes, sugar beets, plantation crops (such as
bananas, fruit trees, rubber trees, tree nurseries), vines, citrus,
olive, amenity, asparagus, bushberries (such as blueberries),
caneberries, cranberries, flax, grain sorghum, okra, peppermint,
rhubarb, spearmint, turf grass, grapevine and sugarcane. In this
invention, treatment of sunflower and cereal are particularly
beneficial.
[0062] All percentages are given in weight % unless otherwise
indicated.
[0063] Embodiments of the invention will now be described by way of
the following examples, which are provided for illustrative
purposes only, and not intended to limit the scope of the
disclosure.
EXAMPLES
Example 1
Preparation of Amorphous Tribenuron-Methyl in Accordance with the
Disclosure of EP 0202830
[0064] To a solution of 2-carbomethoxybenzenesul-fonyl isocyanate
(22.4 g 93.0 mmol) in dichloromethane (100 mL) was added
2-methoxy-4-methyl-6-methylamino-1,3,5-triazine (10.7 g, 69.6
mmol), followed by a catalytic amount of
1,4-diaza[2.2.2]bicyclooctane. After stirring overnight at ambient
temperature under a nitrogen atmosphere, the reaction mixture was
concentrated in vacuo. The residue was triturated with diethyl
ether and then washed with 1-chlorobutane to yield the title
compound as a white powder (28.8 g).
##STR00003##
[0065] As shown in FIG. 4, the X-ray powder diffraction pattern of
the resulting tribenuron-methyl product has no significant
individual signals or peaks, which indicates the tribenuron-methyl
product prepared in accordance with the disclosure of EP 0202830 A1
is amorphous.
Preparation of Crystalline Modification I of Tribenuron-Methyl
Example 2
Crystallization from Methanol
[0066] Tribenuron-methyl sample prepared in Example 1 (10 g) was
taken in a three-necked round bottom flask along with methanol (60
mL) and the resulting slurry was heated to 50.degree. C. to get a
homogeneous solution. The insoluble particles, if any, were
filtered and the solution was slowly cooled to room temperature.
Upon cooling, fine crystals were formed and the heterogeneous
mixture was stirred at room temperature for 2 hours. Then, the
slurry was filtered and washed with methanol (3 mL). The filtered
crystals were dried under vacuum in order to remove the methanol
traces from the crystalline product. The crystalline product thus
obtained had a purity of >98% and was recovered at not less than
80% yield.
[0067] The obtained crystal was analyzed by IR, X-ray powder
diffraction and DSC, and found to be crystalline modification I of
tribenuron-methyl as shown in FIGS. 1, 2 and 3, respectively.
[0068] Differential scanning calorimetry (DSC) (FIG. 3) shows an
endothermic melting peak with onset at 132.3.degree. C. and peak
maximum at 139.4.degree. C. as shown in FIG. 3.
[0069] IR spectrum of the crystalline modification I of
tribenuron-methyl shows the functional group characteristic
vibrations at 2957.46, 2160.18, 2032.70, 1728.01 and 1552.05
cm.sup.-1 as shown in FIG. 1.
[0070] The crystalline modification I of tribenuron-methyl has the
X-ray powder diffractogram shown in FIG. 2 with reflexes summarized
in Table 1 below. The X-ray powder diffractogram were taken using a
diffractometer in reflection geometry in the range from
3.degree.-60.degree. with increments of 0.03.degree. using
Cu-K.alpha. radiation at 25.degree. C.
TABLE-US-00002 TABLE 1 X-ray powder diffractogram reflexes of
crystalline modification I of tribenuron-methyl Crystal Form A 2
.theta. (.degree.) d (.ANG.) 6.47 .+-. 0.2 13.67 .+-. 0.05 10.46
.+-. 0.2 8.46 .+-. 0.05 11.02 .+-. 0.2 8.03 .+-. 0.05 14.01 .+-.
0.2 6.32 .+-. 0.05 15.73 .+-. 0.2 5.63 .+-. 0.05 16.71 .+-. 0.2
5.31 .+-. 0.05 16.98 .+-. 0.2 5.22 .+-. 0.05 21.04 .+-. 0.2 4.22
.+-. 0.05 22.23 .+-. 0.2 4.00 .+-. 0.05 23.26 .+-. 0.2 3.82 .+-.
0.05 25.01 .+-. 0.2 3.56 .+-. 0.05 26.14 .+-. 0.2 3.41 .+-.
0.05
Example 3
Crystallization from Ethanol
[0071] Tribenuron-methyl (5 g) sample prepared in Example 1 was
taken in a three-necked round bottom flask along with ethanol (35
mL) and the resulting slurry was heated to 60.degree. C. to get a
homogeneous solution. The resultant hot solution was filtered to
remove the insoluble (if any) and the solution was slowly cooled to
ambient temperature. Product was precipitated out as fine crystal
during cooling and the mixture was stirred at room temperature for
2 h. Then, the slurry was filtered, washed with ethanol (3 mL). The
filtered crystals were dried under vacuum at room temperature in
order to remove the ethanol traces from the crystalline product.
The crystalline product thus obtained was having a purity of
>98% and the recovered yield was found to be not less than
80%.
[0072] The crystals were characterized as being tribenuron-methyl
crystalline modification I using IR spectrometry, X-ray diffraction
and DSC, as described in Example 2.
Example 4
Preparation of Oil Based Suspension Concentrate (OD)
Formulation
[0073] All the components listed in Table 2 below were mixed
uniformly and ground with a Dyno-Mill (manufactured by Willy A.
Bachofen AG) to obtain an oil based suspension concentrate.
TABLE-US-00003 TABLE 2 Ingredients Weights % Function
Tribenuron-methyl, 40.8 0 Active crystalline modification compound
I, 98% (prepared in Example 2) Amorphous tribenuron- 0 40.8 Active
methyl (prepared in compound Example 1) Modified polyether- 0.5 0.5
Antifoaming polysiloxane agent Ethoxylated castor oil 15 15
Emulsifier Sodium 5 5 Dispersing alkylnaphthalenesulfonate, agent
formaldehyde Silica 2 2 Thickening agent Corn oil Balance Balance
Carrier to 100% to 100%
Example 5
Preparation of Soluble Granules (SG)
[0074] All the components listed in Table 3 below were mixed,
blended and milled in a high-speed rotary mill. Sufficient water
was added to obtain an extrudable paste. The paste was extruded
through a die or screen to form an extrudate. The wet extrudate was
dried at 70.degree. C. in a vacuum oven and then sifted through
0.71 mm-2 mm screens to obtain the product granules.
TABLE-US-00004 TABLE 3 Ingredients Weights % Function
Tribenuron-methyl, 25.51 0 Active crystalline modification compound
I, 98% (prepared in Example 2) Amorphous tribenuron- 0 25.51 Active
methyl (prepared in compound Example 1) Lignosulfonic acid, sodium
5 5 Antifoaming salt, (REAX .RTM. 88B) agent Sodium lauryl sulfate
0.5 0.5 Wetting agent Sodium hydrogen 2 2 Filler carbonate
Potassium sulfate Balance Balance carrier to 100% to 100%
Example 6
Preparation of Water Dispersible Granules (WG)
[0075] All the components listed in Table 4 below were mixed,
blended and milled in a high-speed rotary mill. Sufficient water
was added to obtain an extrudable paste. The paste was extruded
through a die or screen to form an extrudate. The wet extrudate was
dried at 70.degree. C. in a vacuum oven and then sifted through
0.71 mm-2 mm screens to obtain the product granules.
TABLE-US-00005 TABLE 4 Ingredients Weights % Function
Tribenuron-methyl, 25.51 0 Active crystalline modification compound
I, 98% (prepared in Example 2) Amorphous tribenuron- 0 25.51 Active
methyl (prepared in compound Example 1) Alkyl naphthalene 2 2
Wetting agent sulphonate, sodium salt (Akzo Nobel) Lignosulfonic
acid, sodium 15 15 Dispersing salt, REAX .RTM. 88B) agent
Naphthalenesulfonic 6 6 Dispersing acid, polymer with agent
formaldehyde, sodium salt (TAMOL .RTM. NN8906) Non-ionic aqueous
emulsion 1 1 Antifoaming of polydimethylsiloxanes agent Mannitol
Balance Balance Carrier to 100% to 100%
Example 7
Determining Water Solubility
[0076] A stock pH 7 buffer solution was prepared by adding aqueous
sodium hydroxide solution (0.1 M, 145 mL) to aqueous potassium
dihydrogen phosphate solution (0.1 M, 250 mL), and then adding
sufficient distilled water to adjust the final volume to 500 mL. At
least 1 time and up to about 5 times the amount of
tribenuron-methyl needed for saturation was added to a mixing
vessel containing stock buffer solution at the test temperature
(e.g., 20.degree. C.). The mixture was magnetically stirred in the
dark while being maintained at the test temperature. Samples were
periodically removed for analysis. The samples were centrifuged
using a high speed, temperature-controlled centrifuge at the test
temperature for about 20 minutes at >12000 G to remove suspended
particles. An aliquot of each supernatant was taken for
analysis.
[0077] The concentration of tribenuron-methyl in the supernatant
was determined by a high pressure liquid chromatography (HPLC) with
a reversed phase chromatography column and UV detection. The method
should include development of best-fit calibration curves based on
at least three standards using linear regression analysis. Samples
were successively withdrawn from the mixing vessel and analyzed
until three successive samples show little or no variation in
concentration. The test is preferably replicated to ensure
accuracy.
TABLE-US-00006 TABLE 5 Concen- tration Original measured by Formu-
concen- HPLC after Solu- Sample lation tration, % treatment, %
bility Tribenuron-methyl, OD 40 35 88% crystalline modification I,
98% (prepared in Example 2) Amorphous tribenuron- OD 40 14 35%
methyl (prepared in Example 1) Tribenuron-methyl, SG 25 24.9
99.6%.sup. crystalline modification I, 98% (prepared in Example 2)
Amorphous tribenuron- SG 25 15 60% methyl (prepared in Example 1)
Tribenuron-methyl, WG 25 23 92% crystalline modification I, 98%
(prepared in Example 2) Amorphous tribenuron- WG 25 12 48% methyl
(prepared in Example 1)
Example 8
Cleanout Test
[0078] The cleanout test was conducted by dispersing in water a
sample to produce a concentration that is normally used when
applying the herbicide: 25% tribenuron-methyl. The sample was added
to tap water (300 mL) in a 400 mL beaker and magnetically stirred
for 2 minutes. The mixture was then stirred for 2 minutes,
whereupon the resulting dispersion was dispensed in three 100 mL
aliquots to 4-oz (118 mL) polyethylene bottles. The bottles were
capped, inverted twice and allowed to stand overnight.
[0079] After standing overnight, each individual bottle was
inverted twice and the liquid contents were then poured out. Tap
water (10 mL) was added and the bottle was inverted until all
sediment was re-suspended, whereupon the contents were poured out.
Tap water (100 mL) was added and the bottle was inverted twice and
then allowed to stand undisturbed for 10 minutes. The bottle was
inverted twice more and the contents were poured out. Acetonitrile
(10 mL) was added to the bottle to extract any remaining material.
The acetonitrile solution was analyzed by reversed-phase liquid
chromatography with UV detection. The cleanout rating (the
concentration of tribenuron-methyl herbicide in the acetonitrile
solution) is reported in % in Table 6 below. Lower cleanout ratings
indicate more effective cleanout compared to higher ratings.
TABLE-US-00007 TABLE 6 Sample Formulation Cleanout rating, %
Tribenuron-methyl, OD 5 crystalline modification I, 98% (prepared
in Example 2) Amorphous tribenuron- OD 26 methyl, prepared in
Example 1 Tribenuron-methyl, SG 0.1 crystalline modification I, 98%
(prepared in Example 2) Amorphous tribenuron- SG 10 methyl,
prepared in Example 1 Tribenuron-methyl, WG 2 crystalline
modification I, 98% (prepared in Example 2) Amorphous tribenuron-
WG 13 methyl (prepared in Example 1)
[0080] The results in Table 6 demonstrate that the crystalline
modification I of tribenuron-methyl exhibited markedly superior
cleanout properties to those of the known amorphous
tribenuron-methyl product.
* * * * *