CA1202500A - Method for the preparation of water dispersible granular herbicidal compositions with increased thermal stability - Google Patents

Abstract

METHOD FOR THE PREPARATION OF WATER DISPERSIBLE GRANULAR
HERBICIDAL COMPOSITIONS WITH INCREASED THERMAL STABILITY

ABSTRACT
A method for the preparation of water dispersible granular herbicidal compositions having increased thermal stability. Compositions are described which contain low-melting point substituted dinitroaniline compounds.

Description

;~
28, 826 - ~202500 METHOD FOR THE PREPARATION OF WATER DI SPERSIBLE GRANULAR
HERBICIDAL COMPOSITIONS WITH INCREASED THER~L STABILITY
The invention herein described relates to a novel method for the preparation of water dispersible granular compositions containing dinitroaniline herbicides having the following structural formula:
; Rl \ ~ 2 N
02N ~ N02 R3 (I) wherein Rl is selected from H, Cl-C4 straight or branched-; 15 chain alkyl, C3-C4 alkenyl or C3-C4 alkynyl; R2 is selected rom Cl-C6 straight or branched-chain and optlonally substituted with Cl or dCH3, C3-C4 alkenyl or C3-C4 alkynyl; R3 is H, CH3 or CH20CH3; R4 is Cl-C4 alkyl, CF3 or Cl. Compositions of the above hërbicides are charac-terized by improved storage stability a~ elevated tempera-tures.
By way of background, dinitroanaline herbicides are disclosed in United States Patent Nos. 3,920,742;
4,098,812; 4,101,582; 4,124,639; and 49166,908. A number of formula-(I) herbicides, such as N-(l-ethylpropyl)-2,6-dinitro-3,4-xylidine, are desirable for the s,el-ective control of certain grasses in the presence of agricultural crops. Some formula-(I) compounds are efficacious for the control of broadleaf weeds.
Customarily, such herbicides may be formulated . ~.

~2~ S1~0 as wettable powders, dispersible granulars, emulsifiable concentrates, flowables, or similar preparations. The dispersible granular formulations offer ease of handling coupled with redu~ed du~ting, and the absence o~ an organic, flammable and possible toxic solvent that would be present if an emulsifiable concentrate were used instead.
Unf~rtunately, conventional dispersible granular compositions (or wettable powders) containing formula-(I) dinitroaniline herbicides which are solid at room tempera-ture but have melting points below 100C, have a tendency ~o cake, fuse or lump-up when stored at or exposed to elevated temperatures. This is due to excessive softening or partial melting of the herbicides. In general, the above referred-to conventional compositions are prepared by blending and milling the appropriate amount of the selected formula-(I~ dinitroaniline herbicide, a conventional inert carrier, and one or more wetting and/or dispersing agent(s) 9 followed by granulating said blend in the appropriate equipment using a binder solution as the granulating agent.
It has been unexpectedly discovered that the method of present invention permits the preparation of dispersable granular compositions which remain free-flowing and do not agglomerate, lump-up or fuse when exposed to elevated temperatures in the range of about 50C for a prolonged period of time.
About 20 to 70% and preferably 30 to 55% by weight of a dinitroaniline of formula-(I) is melted and heated (preferably 20 to 25C above its melting point) and then sprayed onto about 5 to 25% by weight of a highly sorptive carrier selected from hydrophilic or hydrophobic precipi-tated or fumed silicates or calcium silicates. This mixture - is agitated until all of the molten herbicide ,is absorbed and a free flowing powder is obtained. Next, a clay selected from montmorillonite, attapulgite, bentonite or kaolin is added in amounts sufficient to adjust the sum of all the other ingredients of the composition to 100%. The . .

~z~o~

mixture is then milled (preferably air-milled) to a 5 to lO~m particle size range.
The thus obtained powder i9 then kept in motion and sprayed with an aqueous solution containing from about 2 to 7.5~/O by weight of a formulation of a wetting agent selected from sodium N-methyl-N-oleoyltaurate, octylphenoxy~or nonylphenoxy polyethoxy ethanol, or sodium ~-olefin sulfonate, and a dispersing agent such as sodium lignin sulfonate or the sodium salt of a naphthalene sulfonic acid - formaldehyde condensate which has an average molecular weight of about 600 to 800 Daltons.
Agitation continues until well-formed granules are obtained. The granules are sorted through sieves to obtain the desired size range, dried and if desired blended with about 1 to 5% by weight of a hydrophobic silica powder to enhance the free-flowing characteristics of said formulation. The thus prepared granular composi-tions resist caking and~or lumping when stored at or exposed to temperatures in the range of about 50C, and also disperse well in water without the formation of large particles.
The approximate compositions of the various clays listed above are tabulated helow in Table I. It is recognized that said compositions may vary depending on the origin of the clay in question.

~2~2S~

_ _ U~ o c~ O ~ O O r~
o ~ a~ o I o o o o ~ I I I I
~: .
_ _ _ _ a~
C~ D O C~
o ~ 1-- o ~ ~ U~ ~ ~ ~ ,, ~ ~ ~o V ~ o ~ o C~ o C~i o o ~ I o ~ ~D C`l a~: :
. . _ .
~ a) ,~
~ o 4~ ~ U~
o ~,~ C~ ...... . . . . . .
1~ 1 ~ ~ O ~ a) o ~ I I 1--o , , ,. , , , I U I ~i I
o oo~ C~ ~ ~ CO C~ oo .,~ ~~D ~ O O
J- a~ ~ c:~ ~ JJ o ~ o ~ ~o o o _ _ .
0?~
:
a~ ~
V
. r~ ~ co ~ .
~ ~ ~ o u~
¢ 0~ ~ C~ o o ~ o I I I I oo 0 ~
¢
~ .
~_ ~ O
O O
~ ,~
O O ~: o o , C~ ~ ~_ 0 C~
~ ~ ~ Z ~ o IJ ~ `~
O ~ r~ ) r1 x æ
c~ ~ x a ~ x o ~1 ~ 0 1~ .1 0 ~-I ~ a o a) ^ c .~ ~ rl X X .~ o U~ ~_ X o ~ o X
~' ~n ~ ' ~i "~ ~ ^
c~ ~ n ~ n ~ o O r-l ~r1 0 ~ n , r~ 5 1 ~ ~ V O ~ ~ O U~
I O O ~ 0 C~l O
'S ,~ F~ X C.) Ct~
.

~Y

~%~

The surfactant, referred to hereinabove as "octylphenoxy polyethoxy ethanol" has an average molecular weight of 628 and contains an average of 9 to 10 ethylene oxide units, representing 67% by weight, of said surfac-tant. The specific gravity of this surfactant is 1.065at 25C; ~he viscosity is 240 cps at 25C (Brookfield;
12 rpm), and the flash point is >148C (TOC). Nonylphenoxy polyethoxy e~hanol has an average molecular weight of 640 and contains an average of 9 to 10 ethylene oxide units. The specific gravity of this surfactant is 1.056 at 25C, the viscosity is 240 cps at 25C (Brookfield;
12 rpm) and the flash point is >148C (TOC).
It should be noted that in the above prepara-tion equally good results may be obtained if the solid dinitroaniline herbicide of formula-(I) is added to the agitated highly sorptive carrier which is preheated and ~aintained at a temperature range approximately 20 to 25C higher ~han the melting point of the respective herbicide. As a further alternative, the molten herbicide may be sprayed onto the preheated carrier. This mixture is then cooled to room temperature prior to proceeding with additional steps.
As stated above, the described method yields free flowing non-agglomerating and non-caking compositions of formula-(I) dinitroaniline herb;cides having melting points below 100C. Expecially preferred are the herbi-cides selected from: N-(l-ethylpropyl)-2,6-dinitro-3,4-xylidine, ~ -trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine and N-butyl-N-ethyl-~ -trifluoro-2,6-dinitro-p-toluidine.
A further advantage of the method of the present invention is that when certain of dlnitro-aniline herbicides of formula-(I), which have the progerty of existing in two polymorphic forms, are melt absorbed on highly sorptive carriers of the types named above, they are apparently inhibited from undergoing a polymorphic change. This change normally occurs while said compounds are stored, and usually culminates in the formation o~ large crystals of the thermodynamically stable polymorphic form from the originally microcrystalline, compounds of the metastable ; polymorphic form. The presence of such large crystals is undes-ired in ready-to-use formulations since such crystals may clog the spray delivery system, and may also result in nonuniform distribution on the fields being sprayed. Although melt absor-ption of dinitroaniline herbicides as described above inhibits the formation of such large crystals, we prefer to use the methods described and disclosed in United States Patent No. 4,082,537 and in United States Patent No. ~,150,969. That is, we prefer to incorporate from about 3g6 by weight of sodium dioctyl sulfosucci-nate inhibitor or ethoxylated ~-diamine of the following structu-ral formula:

R5-fH-CH3 fH2CH2OH
N-(CH2)3 N
CH2CH2OH CH2CH2OH (II) wherein R5 is Cg-C20 alkyl, in the respective dinitroaniline herbicide of formula-(I) prior to the preparation of the composi-tions referred to in the body of the present application. If so desired, other materials, such as ethyl cellulose may also be used to improve the high-temperature storage stability of said compositions.
Thus, the preparation of a typical formulation by the method of the present invention may be illustrated as follows:

~.
`h 50~
-6a On a weight basis, 56.97% of N~ ethylpropyl)-2,6-dinitro-3,4-xylidine and 1.51% of sodium dioctyl sulfosuccinate are heated to 70 to 75C until a homogenous melt forms. The melt is maintained at 70 to 75C and is sprayed onto 20.76% by weight of highly sorptive calcium silica-te while the latter is being agitated by suitable means. When all of the melt is absorbed, the powdery solid is cooled to room temperature and 13.79% by weight of bentonite is blended in. The mixture is then ,~, ~L2~

jet milled to a 5 to lO~m particle size range. The resultant powder is tumbled in a suitable granulator and sprayed with an aqueous solution containing 4.65% by weight (of formulation) o sodium N-methyl-N-oleoyltaurate and 2.32% by weight (of formulation) of the sodium salt of naphthalene sulfonic acid - formaldehyde condensate.
The granules are then dried, separated to the desired size range (i.e., about 10 to 60 mesh) and, if desired, coated with about 1 to 5% by weight of a composition of a finely divided sorptive substrate, such as calcined powdered clays, diatomaceous earth, fumed silica, fumed silica which has been made hydrophobic by the replacement of most of the hydrophilic hydroxyl groups, which normally populate the silica surface, with trimethyl siloxyl groups as well as mixtures of said sorpti-~e substrate, to aid in maintaining the free-flow characteris-tics of said compositions.
The present invention is further illustrated by the following examples which are not to be taken as limitative thereof.

Evaluation of dispersible granular formulations of dinitroaniline herbicides prepared by the method of the invention.
The dinitroaniline herbicide and sodium dioctyl sulfosuccinate are melted together and the melt heated to 70 to 75C. The molten material is then sprayed onto a highly sorptive silica with agitation, and agita-tion continues until the melt is absorbed. Next, bentonite is added and the mixture jet milled to a 5 to lO~m particle size range. The milled powder is agitated and sprayed with an aqueous solution of sodium N-methyl-N-oleoyltaurate and the sodium salt of naphthalene sulfonic ac,id formalde-hyde condensate. Agitation is continued until well formed granules are obtained. The compositions of two formula-tions is given in Table II below.

.

~zo~o :

_ ' _ ~ _ _ _ _ N O

O C l O ~_ N ~ J ~ O

:) E _ _ _ _ _ ___ ~ ~ ~ ~ ~ ~ ,o o C) C ~0 l N ~ ~0 O O .
~ _~ __ _ ~ : ~ ~ ~O C~ ~D ~ O
~ . ~ ~ t ~

¢S.. S. cr~ t- J a~ O O ~
:~ ~ bO (\~ l ~r) ~ O O Ir) ~J
bl~, . _ _ _ _ ____ ~ 1.~ . ~C O .

a ~

~2al2S(~

g :
The suspensibility of the above samples is determined as follows: a 5.0 g sample of the appropriate composition is mixed with 50 ml water. The resultant mixture is stirred for 30 seconds, transferred to a 100 ml 5 ~ graduated cylinder, diluted to 100 ml volume, and mixed throroughly by inverting the cylinder end-over-end 30 times at the rate of one complete cycle every 2 seconds.
The graduated cylinder is then allowed to stand in a water bath for 30 minutes at 30C. A 25 ml aliquot is then removed from approximately the middle of the graduated cylinder, and evaporated to dryness. The residue is weighed and the % suspension calculated. Another sample of the suspension is filtered through a wet, 200-mesh screen to determine the % retention. These tests are run lS with standard hard water designed to provide a hardness of 342 ppm calculated ~as calcium carbonate [having the follow-ing composition: 0.304 g CaC12 and 0.139 g MgC12.6H20 per 1000 ml H20] and standard soft water of 34.2 ppm hardness (as CaCo3). The results are presented in Table III below.

.

l~OZSO~

~ -10-12~250~

It can be seen from Table II above, ~hat the granular com~ositions of the invention disperse well both in soft and hard water and do no~ contain significant amounts of large particles.

-Pre aration of a dis ersible ranular herbicidal com-P ~ g position having improved thermal stability.
A sample of the herbicide N-(l-ethylpropyl~-

2,6-dinitro-3,4-xylidine (566.7 g of 90% pure effectively giving 510 g containing 2.5% by weight of sodium dioctyl sulfosuccinate) is melted. The melt is then heated to 70 to 75C. Next, a highly sorptive silica powder (221.2 g) is agitated in a blender and sprayed wich the above molten herbicide. Agitation continues until all of the molten herbicide is absorbed. Bentonite (137.1 g) is added and the blend is then micromilled to a 5 to lO~m particle size range. The micromilled powder is agitated and is sprayed while in motion with a solution of sodium N-methyl-N-oleoyltaurate (S0.0 g) and the sodium salt of naphthalene sulfonic acid condensate with formaldehyde (25.0 g) in 250 g water. Agitation of the blend continues until well-formed granules are obtained. The granules are dried and if so desired, coated with fumed silica (5.0 g), in which case the amount of bentonite used is lowered by the corres-ponding amount (5.0 g).
The thus obtained granules disintegrate well in water and 98% of the particles of the suspension are not larger than lO~m and not more than 0.5% is retained on a 325 mesh sieve.
_ AMPLE 3 Comparison of the method of the invention with a con-ventional preparation of herbicidal compositions to evaluate the inhibition of polymorphic chan~es.
Two compositions are prepared as follows:
35 A. Sorptive, hydrophilic silica powder (14.3 g) is agitated and sprayed with molten N-(l-ethyl-propyl)-2,6-dinitro-3,4-xylidine (36.6 g; 92% pure) held a~ 70 to 75C. Next, kaolin (12.0 g) is added and the blend milled in a jet mill.
B. A control sample is prepared by milling the above components, and in the same proportion, except that the dinitroaniline herbicide is not added in a molten form.
The samples are periodically observed under a microscope for the presence or absence of the unwanted orange macrocrystalline poIymorph of N~ ethylpropyl)-2, 6-dinitro-3,4-xylidine. Results of this experiment are presented in Table IV below.

.

~0 .

2~
, : ~ ~ __ :~
~: ~ W ~ ~o o a) 3 U~
a C~ ~ ~ O ~
r~ ~ ~ rC ~ ~ O
.~ O ~ ~ ~rl_~
0 ~
.,.~ O O ~ O O
~ :~; Ei O ~J~
a) _ ~ . C~ O ~
'O l~i 0 r-( ~ ~ :~ W
~1 r~ C~ ~ O
QJ ~ a) . _ O ~ C~ O o ~ ~ ~ ~ ~1 ~
E~ ~ X ~ ~ JJ
4~ ~ ~ CO L~
C ~J __ ,~ .~ O O
~:: .~ 0 '~0 O
.~ _, cn co u~
_ _ O
J~
O ~

. . .

~z~
_14-The above data show that compositions prepared by the melt absorption process of the invention (Composition A) prevent and/or slow down the formation of the unwanted orange macrocrystalline polymorph.

; Preparation of_a wettable herbicidal composition having im~__ved stora~e stability at elevated temperatures.
~ Sorptive silica (16.2 g) is heated to and agitated at 80C. A blend (17.8 g) comprising. 96.3%
of N~ ethylpropyl) 2,6-dini~ro-3,4-xylidine, 1.1% of sodium dioctyl sulfosuccinate and 2.6% of ethyl cellulose is added in small por~ions. The mixture is stirred and heated until~ all of the molten herbicide is absorbed.
The mixture is then cooled to room temperature and blended with sodium N-methyl-N-oleoyltaurate (2.0 g), the sodium saIt of condensed naphthalene sulfonic acid (2.0 g) and fumed silica (1.7 g). The thus obtained composition is milled to a particle size range sufficiently small to allow the entire sample to pass through a 200 mesh screen.
A sample of the above composition is stored at 50C for 24 hours. This sample remained free-flowing ~no caking~ and also dispersed well in water.

Preparation of dispersible granular herbicidal composition in which ranulation is accom~lished bY water onlY.
g Hydrophilic silica (20.0 g) is agitated and molten N~ ethylpropyl)-2,6-dinitro-3,4-xylidine (50.7 g, 91% pure; also contains 1.1% sodium dioctyl sulfosuccinate and 2.6% ethyl cellulose) maintained at 75 to 80C is sprayed on the silica. The coarse powder obtained is blended with sodium N-methyl-N-oleoyltaurate (2.6 g), the sodium salt of condensed naphthalene sulfonic acid (0.90 g) and kaolin (25.80 g), and the blend milled to,a particle size range sufficiently small to pass through a 200 mesh screen.
A sample (10 g) of the thus obtained wettable powder is agitated while being sprayed with water in ~2~D2 amounts sufficient to form granules which are then dried and classified to a 10 to 30 mesh size range.
Part of the granules prepared as described above are stored at 50C for 24 hours. Tests indicate that both untreated and heat treated (stressed) granules do not disperse well in water, larger (ca. 30 to 50~m) particles~are present and some of the material is retained on a 200 mesh screen.

Pre aration of dis ersible ranular herbicidal compositions p _ p g in which the herbicide is added as a solid material to a heated carrier, and the product &ranulated by water only.
The appropriat~ sorptive carrier is agitated at 60 to 70C and the solid dinitroaniline herbicide added in small portions. Agitation of the mixture continues for about 30 minutes at 60 to 70C untill all of the herbicide is melted and absorbed on the carrier. The ~ixture is then cooled down. The appropriate dispersing and/or wetting agent(s) is (are) added followed by the addi~ion of an inert diluent in amounts sufficient to adjust the mixture to 100%. The thus obtained composition is blended and milled to yield a wettable powder with a particle size distribution such that the composition completely passes through a 200 mesh screen.
The compositions obtained as described above are agitated and sprayed with water to yield granules of lO to 60 mesh size. The compositions prepared are summar-ized in Table V below.

~25 c r---- 0 ~ ~ R~ r I

X ¦ ~ I ~ N ~ 5 ~

l ~ ¦ o ~ o ¦ I L ~ ~
~o ~ ~ t- ~ a~ 1~ cr~ : ~ ' ~I ~ 5 N N _ N O D

D ¦ ¦ bO ¦ ~0 ~
~1 ~ ~- I -I 0~ -I c~ ~c ¦ ~- ~ ~
L ~ L 5 O O 5 3 5 ~ N

~ I R ~ R - ¦ R ¦ ~I f ~ ~ D ~ ~ ¦ R
C D. O ~ ~ ~3 n :3 ¦ - C C I a D ¦ Ei C

1~02S~)q) Samples of each of the above granular composition are stressed by storage at 50C for four days.
The stressed samples do not disperse well in water although the wettable powders from which they were prepared have satisfactory dispersion properties.

Preparation of wettable powders by conventional methods.
Precipitated silica, octylphenoxy polyethoxy ethanol, sodium liqnin sulfonate and attapulgite are thoroughly blended in predetermined proportions. The resultant blend is agitated and sprayed with the appropri-ate amount of molten dinitroaniline herbicide at a temper-ature range of 70 to 80C. Following completion of this addition the blend is allowed to cool and is then air milled.
The composition of the samples prepared by the above method is given in Table VI below.

~zo~o~

~ S~ ~ d ~ ~ o o o o o o ~ L ~J ~ O ~D ~ `D 3 O

0;
~o 1 t ~~ o o o o o o D~D O l ~0 ~ ~0 3 O
D r--_ _ ----r r ~
.~ ~ '~ ~ l a a o x O o c ,,' ' x na .

o o a 0 ¦ V I ~ ~ ~ c Both of the above formulations failed to absorb the molten dinitroaniline herbicide and on cooling became~solid and lumpy and had to be hammer milled prior to air milling. These powders did no~ disperse well in water, nor could they be granulated in a satisfactory manner.

-Preparat on of dispersible ~ranular herbicidal compositions dichloro hen l-l-methYl urea.
P Y
The appropriate amounts of l-butyl-3-(3,4-dichlorophenyl)-l-methylurea, precipitated silica, octylphenoxy polyethoxy ethanol, sodium lignosulfonate and attapulgite are mixed and thoroughly blended. Next, while be;ng agitated, the blend is sprayed with the appro-priate amount of molten dinitroaniline herbicide main-tained at 70 to 80C. The mixture is cooled, air milled, and then granuiated with water using suitable equipment.
The granules are dried and classified according to the desired particle size range.
These dispersible granular compositions are then evaluated by the method of Example 1 as to their suspensibility in water.
The composition of the formulations and the results of the suspensibility tests are given in Tables VII and VIIa below. It can be clearly seen that these compositions and their method of preparation are inferior as compared to those of the invention.

~OZ500 ~ ~ ' __ _ 1o . 1o o o o .

~ : m ~ l O o D N tr~ ~J O

O E ____ _ _ __ _ O O O O O O O
E bO l S D ~_ =l ~D 11~ O

r ~ .
D __ ___ _ _ _ _ _ 1~ ~ +~ ~
u~ O O O O O O

~r-l b0 O l O ~O ~__ ~ ) _ ~e r __ 1O

E ¦ 8 1 <~I C ~ O ~ ~ 0 1 ~ e ~ ~
a) o x o ~ o~ J~ O C~
O r~l ~ ~I Z ~~ ~3 ~ O S C ~
¦ o I 'e~ e, ¦ I e ~

~2~

` ~ ~

H O 0~\ ~J In ::r ~
~ c) u~ o o u~ ~
~ ~ ~0 ~:
o ~3 :
:~
D ~ ~) ~ .~ ~ ~ ~ J~
~n ~1 ~ ~ S~
~' D 0~ D a~
.,~ ~ ._, a)~ ~ a~
S~ C~ ~ C~ ~ .

O ~ 3 ::~
~: IS Y ~ ~ ~ l o ¢ a:

O _ 't

Claims (7)

WHAT IS CLAIMED IS:

1. A method for the preparation of dispersible granular compositions comprising: melting on a weight basis about 20 to 70% of a compound having the following structural formula (I) wherein R1 is hydrogen, C1-C4 straight or branched-chain alkyl, C3-C4 alkenyl or C3-C4 alkynyl; R2 is C1-C6 straight or branched chain alkyl and optionally substituted with Cl or OCH3, C3-C4 alkenyl or C3-C4 alkynyl, R3 is hydrogen, CH3 or CH2OCH3; R4 is C1-C4 alkyl, CF3 or Cl; and mixing with said melt on a weight basis about 1 to 3% of sodium dioctyl sulfosuccinate or ethoxylated .beta.-diamines having the following structural formula wherein R5 is C9-C20 alkyl; and heating said mixture at 20 to 25°C above the melting point of the compound of formula-(I); spraying said melt onto 5 to 25% by weight of a highly sorptive hydrophilic or hydrophobic precipita-ted or fumed silica or calcium silicate with agitation until all of the melt is absorbed; cooling the thus obtained mixture; adding a clay selected from attapulgite, montmorillonite, bentonite or kaolin in amounts sufficient to adjust the sum of all the other ingredient of the composition to 100%; milling said mixture to a particle size range of from 5 to 10µm; and granulating same with an aqueous solution of 2 to 7.5% by weight of a wetting agent selected from N-methyl-N-oleoyltaurate, octylphenoxy polyethoxy ethanol, or nonylphenoxy polyethoxy ethanol, and 2 to 6% by weight of a dispersing agent selected from sodium lignin sulfonate and the sodium salt of a naphtha-lene sulfonic acid-formaldehyde condensate.

2. A method according to Claim 1, wherein said formula-(I) compound is selected from N-(1-ethylpropyl 2,6-dinitro-3,4-xylidine, .alpha.,.alpha.,.alpha.-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine or N-butyl-N-ethyl-.alpha.,.alpha.,.alpha.-trifluoro-2, 6-dinitro-p-toluidine and comprises 30 to 55% by weight of the formulation.

3. A method according to Claim 2, wherein 40 to 55% by weight of N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine is melted with 1.5 to 2.5% by weight of sodium dioctyl sulfosuccinate; the amount of highly sorptive silica is 15 to 25% by weight; the wetting agent is sodium N-methyl-N-oleoyltaurate used in amounts of 2.5 to 5% by weight;
the dispersing agent is the sodium salt of naphthalene sulfonic acid-formaldehyde condensate; the clay is benton-ite used in amounts sufficient to total the formulation to 100%.

4. A method according to Claim 3, excepting that 0.5% by weight of fumed silica is used to coat the granules and the amount of bentonite used is lowered by 0.5%.

5. A method according to Claim 3, wherein the amount of N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine is 51%; the amount of sodium dioctyl sulfosuccinate is 2.5%;
the amount of silica powder is 22.1%; the amount of bentonite is 13.7%; the amount of sodium N-methyl-N-oleoyl-taurate is 5% and the amount of the sodium salt of naphtha-lene sulfonic acid-formaldehyde condensate is 2.5%; and the amount of bentonite is sufficient to adjust the composition to 100%.

6. The method according to Claim 5, wherein the granules are coated with 0.5% by weight of fumed silica.

7. A dispersible granular composition of a 10 to 60 mesh size range comprising a mixture of 20 to 70% by weight of a compound having a melting point below 100°C
and having the following structural formula (I) wherein R1 is hydrogen, C1-C4 straight or branched-chain alkyl, C3-C4 alkenyl or C3-C4 alkynyl; R2 is C1-C6 straight or branched-chain alkyl and optionally substituted with Cl or OCH3, C3-C4 alkenyl or C3-C4 alkynyl; R3 is hydrogen, CH3 or CH2OCH3; R4 is C1-C4 alkyl, CF3 or Cl; and contain-ing 1 to 3% by weight of sodium dioctyl sulfosuccinate or an ethoxylated .beta.-diamine having the following structural formula (II) wherein R5 is C9-C20 alkyl, absorbed in the molten state onto 5 to 25% by weight of a highly sorptive hydrophilic or hydrophobic precipitated or fumed silica or calcium silicate and a clay selected from attapulgite, montmoril-lonite, bentonite or kaolin in amounts sufficient to adjust the sum of all the other ingredient of said composition to 100% wherein said mixture comprises a particle size range 5 to 10µm prior to granulation with an aqueous solution of 2 to 7.5% by weight of a wetting agent selected from N-methyl-N-oleoyltaurate, octylphenoxy polyethoxy ethanol, and 2 to 6% by weight of a dispersing agent selected from sodium lignin sulfonate and the sodium salt of a naphtha-lene sulfonic acid-formaldehyde condensate.