AU463549B2 - Fungicidal composition - Google Patents

Description

3 8 .3 2 3/72 The oresent invention relates to fungicidal compositic

having improved stability and based on dithiocarbamates, and

process for controlling fungi with these compositions. It is known to use dithiocarbamates, for example the

product obtained by coprecipitation of the ammonia complex of the zinc salt of 1,2-propylene-bis-dithiocarbamic acid anc

N,N'-poly-1,2-propylene-bis-(thiocarbamoyl)-disulfide, as fur

ides.

These dithiocarbamates are, however, subject, especial

at elevated temperature, to slow decomposition.

We have now found that decomposition in a fungi-

cidal composition based on dithiocarbamates occurs to a lessi

extent when the composition contains a particulate solid car:

having a pK value of from 3.3 to 6.8. The preparation of the active ingredient has been

described in German Printed Application No. 1,OP5,709.

The active ingredient employed for the following

experiments was obtained by coprecipit-ation of the ammonia

complex of the zinc salt of 1,2-propylene-bis-dithiocarbamic

acid and N,N'-poly-1,2-propylene-bis-(thiocarbamoyl)- disulfide. By dithocarbamate we mean a salt, particularly a meta or alkali metal salt, for instance the sodium, potass"-

iuum, copper, iron, manganese or zinc salt, or an ammonium s

of a dlthiocarbamic acid, for example monomethyldithiocarbam

acid, dimethyldithiocarbamic acid, monoethyldithiocarbamic

acid, ethylene-bis-dithiocarbamic acid, 1,2-propylene-bis-

dithiocarbamic acid, 1,3-propylene-bis-dithiocarbamic acid,

4635.49

38.323/ n Dr coprecipitations of these salts with thiuram disulfides,

for example N,N'-poly-1,2-propylene-bis(thiocarbamoyl)-di-

sulfide. The salts may be used as such or in complex form,

for instance in the form of a complex of ammonia.

wt% mixtures of the active ingredient with

carriers having different pK values were prepared and stored 0 at room temperature, 30 0 C, 40°C and 50 C. At different points

in.time the concentrations of carbon disulfide still present

were determined and the t8 0 and t 5 0 values (tso the time

after which there is still 80% of the original active

ingredient concentration present; tSo half-life) were

worked out from the degradation curves. The results of these

experiments are contained in the following table. The

stability of the active ingredient used for these experiments

is also included without carrier in the table. In the.

table the carriers are listed according to.pK values.

4635,49

38. 3 23 /7-2 T

(D 0 E- CM

0 0( I 1 1 4.3 0 -9

0 0

0 e Cd(I c 0 0

0 I O 0 CMe' UN-u

0 0 0 L CM cy'

CC) 0 0 a a a

C

(D 0 0

0 0 C ocio lU\-

4 0. 09 4 '-4

0. 0:4 d cu .0 0 4

CH '1 00

0 Hr 0 4 0d H 0 ViO 0 W 0 i 0~ Hd Wo 4.d.43

-4I 4635.49

38.323/72 These results show that only solid carriers having

a pK value between 3.3 and 6.8 stabilize the active-ingred- ient, whereas other carriers result in more rapid degradation. It is not possible to use the undiluted active ingredient on its own in practice because the small amounts required for fungus control cannot be distributed uniformly. The pK value is a measure of the acidity of solid surfaces, or of their ability to give off protons Hanmmett,

A.J. Deyrup, J. Am. Chem. Soc., 5, 2721, 1932; J. Am. Chem. 6 It is Soc., 56, 827, 1934; Chem. Rev., 67, 1935).

determined by dabbing a slurry of the carrier in isooctane using solutions of various color bases which must have different dissociation constants and which, when acid, must have a different color tone than when neutral. For most carriers, surface acidity gives values completely different from conventional characterization by measuring the pH in aqueous suspension. According to Ullrlch Ullrich, Chem. Techn. 16, 263, 1964), the pH of, for

instance, an attapulgite mineral is from 8.1 to 9.5 (measured in a suspension of 20 g of carrier in 80 ml of water), whereas its pK value is corresponding to the acidity of a sulfuric acid. The solid carrier in the fungicidal composition according to this invention should be in particulate form. 5 By this we mean particles having a size of 10 to 101 mm, 3 particularly 10 to 10 2 mm.

It is preferred to use silica gel as the solid

particulate carrier; its pK value is within the above-

mentioned range. The stability of the compositions according

to the in-vention is extremely good. The particulate solid

4635.49

38.323/72 carr r having a pK value of from 3.3 to 6.8 may be used on

its own or in admixture with other mineral carriers; it is,

however, essential that the pK value of this composition of

carriers be between 3.3 and 6.8. It is possible in this way

to use carriers having a pK value of less than 3.3 or greater

than 6.8, which are not suitable per se for use in the com-

positions of the invention, by mixing them with carriers having a pK value of from 3.3 to 6.8 to attain a pK value of

the mixture of from 3.3 to 6.8, as the following examples show

Carrier or mixture pK

kaolin 0.4 clay 0.4 to silica gel K 322 3.3 silica gel B wind-sifted 6.8

BLP/3 (calcium carbonate) 6.8 clay silica gel B wind-sifted (1 1) 3.3 kaolin silica gel K 322 (1 1.5 to 3.3

kaolin silica gel B wind-sifted (1 1) 3.3 BLP/3 silica gel K.322 (1 1)

Mixtures of fungicidal dithlocarbamates and a solid

carrier or mixture of solid carriers having a pK value of from 3.3 to 6.8 are stable. They are suitable for controlling

fungi, especially in the plant protection field. The mixtures

according to the invention may be applied in conventional

manner, for instance by dusting or spraying. The agents

should be used prophylactically,*i.e., to prevent plants being infected by fungus spores.

The ratio of dithiocarbamate to total solid carrier

may vary from 5 to 90 parts by weight of dithiocarbamate to

-6 4635.49

38.323/72 from 95 to 10 parts by weight of carrier. The fungicidal

mixture preferably contains 70 to 80 parts by weight of di-

thiocarbamate in admixture with 30 to 20 parts by weight of

solid carrier. This solid carrier may, as stated above, be

a mixture of conventional mineral carriers with silica gel.

A fungicidal composition having increased stability

to counter unsuitable storage conditions is obtained by add-

ing,.in addition to the particulate solid carrier having a

pK value of from 3.3 to 6.8, urotropine to the mixture. The

concentration of urotropine in the whole fungicidal composit-

ion may vary from 0.5 to 10% by weight, and is preferably 1

to 5% by weight. The stable fungicidal compositions according to the

invention may also contain conventional dispersants or wetting

agents. They may additionally contain further active ingred-

ients such as substances having a fungicidal, insecticidal or

herbicidal action. The compositions of the invention are

produced by intensively mixing and, if desired, finely tri-

turating the dithiocarbamate and solid carrier or mixture of

solid carriers having a pK value of from 3.3 to 6.8-and, if

desired, other components such as urotropine and further

active ingredients, dispersants or wetting agents. Mixing

may be carried out in conventional mixing equipment, for

instance a ribbon mixer. It is advisable during mixing and

trituration to prevent the mixture heating up above approx-

imately 60°C. The components of the composition are, depend-

ing on the amount and the mixing in-tensity, mixed together

in the.mixing apparatus for from 30 minutes to 3 hours. The

compositions may then be stored for fairly long periods of

time.

46 35.49

38,323/72 com- The following compositions are typical of the

positions of the invention. The compositions are prepared

by intensively mixing 70% by weight of active ingredient

and 11.5% by weight of conventional dispersants and wetting

agents, the balance being various carriers or mixtures of

and subsequently triturating the mixture in an carriers,

attrition mill. The experiments were carried out with

kaolin (a carrier.having a pK of silica gel B wind-

sifted (a carrier having a pK of silica gel K 322 (a

carrier having a pK of BLP/3 (a carrier having a pK

greater than and urotropine. The results are given

in the following table.. Where t8 0 and t50 could not be determined, the carbon disulfide concentration is given in brackets in by weight of the original concentration after

weeks' storage.

The active ingredient was obtained by coprecipitat

ing the ammonia complex of the zinc salt of 1,2-propylene-

bis-dithiocarbamic acid and N,N'-poly-1,2-propylene-bis-

(thiocarbamoyl)-disulfide.

active ingredient 11.5% dispersant and wetting agent t8 0 [weeks] t5o [weeks)

carrier I carrier stabil- 0 II Izer 50 C 400 C 500 C 400C uro- tropine]

18.5% B 22 0.25 17 0.75

.12.5% B 22 6.0% 1.25 15 2.25 s.g.B.t.

5.0% 3 14 (83%) 10.5%

4.5% 5 13 22 (82%:

3.5% 7.5 14 (84) 25 (84%

-8- 4635.49

38.323 /2 active ingredient 11 dispersant and wetting agent t 8 0 [weeks] t5 0 [weeks] carrier I carrier f stabil- II izer 500 C 400 C 50 0 C 4 0 0C

tropine]

B 22 12.0% 1.25 15 2.25 s.g.B.w.

10o.0% 3 12 (841)

9.0% 5 19 (84% 7.5% 7.5 10 29 (85%1 B 22 12.0% K 322 1.25 17 2.0 (73%)

l.0% 3 13 (84%) 9.0% 5 16 7.5% 7.5 8 23 (79f% 18.5% BLP/3 0.25 8 0.75 18

12.5% BLP/3 6.0% K 322 0.5 16 1.5 10.5% 5.0% 3 13 30 5 9 (864) 22 (84%) 3.5% 7.5 18 24 (91%) BLP/3 12.0% K 322 0.75 13 1 .75 26

10.0% 3 15 30 (81%)

9.0% 5 11 30 (86%) 7.5% 7.5 17 27

B 22 kaolin B 22 silica gel B wind-sifted K 322 silica gel K 322

The examples illustrate but do not limit the invention

4635,49

Claims (1)

1. 38.323/72

   THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-

   1. A fungicidal composition based on a dithiocarb-

   amate which contains a particulate solid carrier having a pK value of" from 3.3 to 6.8 and a particle size, between 10 1 and 10 mm, the ratio of dithiocarbamate to total solid carrier

   the ange of 5 to 90 parts by weight dithiocarbamate to being in

   to 10 parts by weight carrier.

   2. A composition as claimed in claim 1 containing silica gel

   as carrier.

   3. A composition as claimed in claim 1 containing a particula

   solid carrier having a pK value less than 3.3 or greater than

   6.8 and a particulate solid carrier having a pK value of from 3.3 to 6.8, the pK value of the carrier mixture being from 3.3 to 6.8

   4. A composition as claimed in any of claims 1, 2 and 3

   containing 0.5 to 10% by weight urotropine.

   A process for controlling fungi comprising applying theret

   in fungicidal amounts, a composition as claimed in any one of

   claims 1 to 4.

   DATED THIS 21st day of MARCH, 1975.

   BADISCHE ANILIN SODA-FABRIK AKTIENGESELLSCHAFT

   EDWD. WATERS SONS, Patent Attorneys,

   Q Queen Street, MELBOURNE. VIC.

   4635.49