HU195608B - Granulated herbicides containing as active substance derivatives of diocarbamate - Google Patents

Abstract

Novel herbicidal composition based on thiocarbamate which has only a faint odour and which is composed of porous granules impregnated with a herbicide based on thiocarbamate and which are coated with a coating material composed of vulcanised glycerides of one or more unsaturated aliphatic C10- to C24-acids and an antioxidant or of their copolymers of mono- and polycyclopentadiene and an antioxidant. The composition allows a prolonged storage period of the herbicide to be obtained while reducing efficiently the odour of the composition.

Description

FIELD OF THE INVENTION The present invention relates to a low odor particulate herbicidal composition.

More particularly, the present invention relates to a porous particulate composition impregnated with a herbicidal thiolcarbamate and coated with a substance which reduces the odor of the herbicidal product. More particularly, the present invention relates to a coated herbicidal composition having a sustained herbicidal action. __

Chemical herbicides are widely used to protect crop plants from weeds and other vegetation that inhibit the development of crop plants. The form in which such herbicides are used in field cultivation varies greatly depending on the chemical and physical properties of the active ingredient, the type of plant to be protected, the weeds to be controlled and the way in which the herbicidal action is achieved. Consequently, herbicidal formulations range from liquid systems, including solutions, emulsions and suspensions, to solid systems, including pastes, powders, and granular materials.

In some cases, particulate formulations have advantages over other types of formulations. The particulate compositions are porous, inert solid particles having a diameter of 1 to 2 mm and impregnated with herbicidal agents. Unlike most liquid formulations, particulate formulations do not need to be diluted prior to field application and, due to their mass, can be effectively dispersed from an aircraft, resulting in large surface applications in a short period of time. Granular formulations are particularly well suited for flooded areas where, due to their mass, they are penetrated by water to the soil, where herbicide action is most needed. Granular formulations also increase the versatility of the liquid herbicides by allowing them to be stored, transported and used as if they were solids. Particulate compositions are particularly useful for formulating thiol carbamate herbicides.

Due to the volatility of herbicidal thiol carbamates, there are major problems with the storage and use of many particulate thiol carbamate formulations. The liquid in the pores of the granules has a very high concentration of thiolcarbamate and is in direct contact with the atmosphere.

Coating such herbicidal granular formulations with vegetable oil reduces the odor, but also reduces the effectiveness of the herbicidal granular formulation after storage and transport. The addition of an antioxidant increases the storage stability of the coated herbicidal granular composition.

Various methods are used in the art to reduce the volatility of chemical herbicides. Such a method is described in Dutch Patent Application Publication No. 68,14540, wherein a starch or polyvinyl alcohol coating is applied to a granular composition impregnated with a herbicide to reduce the volatility of the composition.

No. 2,075,344. British Patent Application Serial No. 4,969,400; A particulate herbicidal composition containing a thiolcarbamate active ingredient coated with a dicyclopentadiene / linseed oil copolymer is described.

The present invention provides a granular herbicidal composition containing thiolcarbamate as an active ingredient

R ²

II /

R ¹ - SC - N (I)

R ³ contains a compound of the general formula

in the formula

R ¹ is C ¹ -C 4 alkyl, and

R ² and R ³ together form a C 5 -C 7 alkylene group - which

a) cured glyceride of one or more C10-C24 unsaturated aliphatic acids, or

b) coated with a cured mono- or polycyclopentadiene copolymer of one or more C 10 -C 24 unsaturated aliphatic acids, the coating comprising an antioxidant, wherein the coating comprises from 1 to 30% by weight of the composition, the amount of antioxidant being calculated as 0.1 0.8 w / w.

The antioxidant is of decisive importance in the granular herbicidal composition according to the invention, since in the absence of the antioxidant, the thiolcarbamate herbicide is prone to degradation upon contact with the oil coating. As a result, the efficacy of the granular herbicide formulation is reduced.

Preferred thiolcarbamate agents are those wherein R ¹ is C 2-4 alkyl; and

R ² and R ³ together form C 5-7 alkylene.

As used herein, the term "alkyl" refers to both straight and branched chain groups. Alkyl groups include, for example, methyl, ethyl, η-propyl, isopropyl, n-butyl, sec-butyl, isobutyl. "Alkylene moiety" means a moiety containing a multiple of -CH ₂ - optionally substituted by alkyl groups. Examples of such groups _E -CH ₂ CH ₂ CH ₂ CH CH ₂ - / pentamethylene /, .alpha.-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ / hexamethylene /, .alpha.-CH ₂ CH ₂ CH ₂ CH ₂ GH _{2 CH2 CH2} / heptamethylene /, a - CH ₂ CH / CH ₃ / CH ₂ CH ₂ CH ₂ CH _{2/2-methyl-hexamethylene} / and the like.

The term "aliphatic acid" as used herein refers to compounds of formula (11).

SHE

II

In the formula R-C-O-H / 11 / e, R is an unsaturated hydrocarbon group.

The said unsaturated groups are those containing up to three multiple bonds. These bonds may be double or triple bonds. Examples of such acids are palmitic acid, stearic acid, linoleic acid, linoleic acid, oleic acid, licanoic acid and tartaric acid. All carbon ranges include upper and lower limits _L ____________ __________ <

The term "herbicide" as used herein refers to a compound or preparation that regulates or modifies the development of plants. The term "effective amount of herbicide" refers to an amount of a composition or agent of the invention that produces a regulatory or modifying effect. Regulatory or modifying action involves development other than natural development. These include eradication, developmental delay, defoliation, drying, control wilting, dwarfing,

-2105 608

I shrubbery, stinulation, leaf burn, shrinkage and the like. As used herein, the term "plant" includes germinating seeds, hatched seedlings and mature vegetation, including roots and above-ground parts.

The particulate feedstock used in the composition of the present invention may be any porous solid which is insoluble in water or in the liquid material used for the particulate material. The particulate material may be formed by extrusion, aggloinerization or milling, but may also be a naturally occurring material. The latter material can be used in its natural state or physically transformable before use, so that these materials can be dried, crushed and sieved to achieve the desired size and moisture characteristics. The particle size is generally in the range of one millimeter to one centimeter in diameter or length. A typical grain cell orb is between about one and two millimeters. Examples of such carriers are vermiculite, sintered particulate chalk, kaolin, attapulgite chalk, bentonite chalk, talc, pyrophyllite, diatomaceous earth and particulate carbon. A commercially available conventional carrier is kaolin, a naturally occurring material consisting of chalk-seric particles in choline (0.35 to 1.2 mm in size). They are composed as follows:

and are derived from the unsaturated aliphatic acids described above. Thus, R ⁴ , R ^{5 and} R ^{6 are} as defined for R 11 and are unsaturated analogues thereof. Examples of such oils are castor oil, linseed oil, menhaden oil. oiticica oil, safflower oil, sardine oil, soybean oil, sunflower oil, wood oil, corn germ oil, shallot seed oil, perilla oil, poppy oil, rapeseed oil and coconut oil. The acids that form the acid moiety of these oils are saturated acids such as myristic acid, palmitic acid, stearic acid, arachic acid, benenic acid and lignoceric acid, and unsaturated acids such as myristoleic acid, palmitoleic acid, linoleic acid, erucic acid, ricloleic acid, and eleostearic acid. Oils for use according to the invention are those having acid groups containing from 24 to 25 carbon atoms, preferably from RCOO to 10. The most preferred oil is linseed oil, of which. its composition is in the following ranges / percentage by weight /:

unsaturated acids: linoleic acid oleic acid linoleic acid saturated acids: palmitic acid

CI »Η3 {> θ2 Cl» Ι1.14θ2

C | »113 2 θ2

C.ftHjíOj

- 65 12 34

7- 27

Percentage stearic acid 0 | _Κ Η _{3 ()} Ο ₂ 2 - 5 silicon dioxide / SiO ₂ / 45 - 48 arachinic acid C ₂ H, O ₂ 0.3 0.9 alumina / A 1 ₂ O ₃ / 42 - 45 lignoceric acid C ₂₄ H _{4 S} O ₂ traces-0.4 iron oxide / Fe ₂ O ₃ / 2.0- - 2.5 . Coating agents, oils, may be used titanium oxide 3 2q in naturally occurring form, either mono- or polycyclopentadic, preferably dicyclopentadic, copoly- altogether 100.0

Thiol carbamates for use in the compositions of the invention include, for example, S-ethylhexahydro-1H-azepine-1-carbothioate / molinate / cut-S-isopropylhexahydro-1H-azepine-1-carbothioate.

The amount of thiol carbamate present in the pore portions is not critical to the invention and may vary within wide limits, which is primarily determined by the degree and type of control desired and the potency of the thiol carbamate herbicide employed. In general, the herbicidal composition will comprise from 1 to 20% by weight, preferably from 5 to 15% by weight, of the herbicidal active ingredient based on the total weight of the composition.

The coating materials used in the compositions of the present invention are selected from glycerides of one or more unsaturated fatty acids. Although the presence of unsaturated groups is important for the curing of glycerides, they can also be present without seriously damaging the utility of the glycerides. In fact, the glycerides available are generally a mixture of different acid groups, so that one molecule is different from the other, including both saturated and unsaturated groups. These materials are vegetable and animal products, commonly referred to as drying oils, because they can harden upon exposure to heat, contact with air, or the action of certain metal salts to form a dry, hard resin film. The structure of such oils can be described by the formula / ΠΙ /

R ⁴ COO-CH ₂

R ^s C00-CH

I / ΠΙ /

R ⁶ COO-CH ₂ in this formula may have the same or a gg of acid moieties. The content of cyclopentadiene is quite high, such as 70% by weight, preferably less than 25% by weight, and is intended to facilitate rapid drying and increase the water resistance of the coating.

Hardening or "drying" of oils, as they are commonly called, is accomplished by exposing them to air for extended periods of time, applying heat, or using drying catalysts. Drying catalysts are advantageous because herbicidal thiolcarbamates tend to evaporate when heat is applied and air drying takes a long time. Useful drying catalysts include metal salts of naphthenic acid or other aliphatic acids, such as cobalt, lead, manganese, cerium, copper, chromium, iron, tin, vanadium and zirconium salts of linoleic acid, resin acid or naphthenic acid. The amount used is not critical to the amount of drying oil and can vary widely depending on the thickness of the coating formed and the drying time. For example, a catalytic amount is sufficient to increase the drying rate. The amount of catalyst is generally from 0.01 to 20% by weight, preferably from 0.01 to 5% by weight, based on the coating. Single or combined catalysts may be used.

Drying may be further accelerated by using an oil which has been heat-treated prior to application to the particulate material. There are two generally known methods. heating the oil and blowing warm air through the oil. In both cases, a viscous, faster drying oil is obtained.

The antioxidant may be added to the particulate composition by mixing with the herbicidal active ingredient before impregnating the particulate material or blending with the oil prior to coating the impregnated particulate material. Although all anti-31

195,608 oxidants chemically compatible with thiolcarbamate and coating oil may be used, but the preferred antioxidant is butylhydroxyanisole (BHA), butylhydroxytoluene (BHT), or mixtures thereof. The preferred antioxidant is tenox-4, which is a mixture of BHA and BHT in corn germ oil.

The amount of antioxidant is in the range of 0.1 to 0.8% by weight based on the total weight of the composition, with a preferred amount of 0.1 to 0.4% by weight, especially 0.2% by weight.

The thickness of the coating is not critical to the invention and may vary within wide limits depending on the degree to which thiolcarbanate is released to control plant growth. The degree of control depends on the amount of thiolcarbamate present in the pores of the granules, the potency of the thiolcarbamate, the crop to be protected and the weeds to control the granular composition. The coating is usually that. 1 to 30% by weight of the whole composition, preferably 5 to 10% and in particular 7% by weight.

In preparing the composition, the thiolcarbamate agent is first added to the particulate material, followed by the addition of a glyceride-containing coating together with the antioxidant. Then cure. Each of the ingredients is applied by conventional methods. The most convenient method is by spraying the liquid mist mist directly onto the particulate material, which is mixed well to achieve the best and even contact with the mist spray. When a drying catalyst is used, it is combined with the glyceride / antioxidant mixture to form a homogeneous liquid mixture which is sprayed onto the particles.

The temperature at which the liquid ingredients are applied to the particulate material is not critical. However, it is most convenient to use the components at approximately ambient temperatures, such as 15 to 30 ° C, to minimize the possibility of volatile constituents being released into the atmosphere.

The herbicidal composition according to the invention has substantially the same activity as commercially available impregnated granules.

The following examples illustrate the utility of the granular herbicidal composition according to the invention. The examples only illustrate some possibilities, but are not intended to limit the invention.

Example 1

The device

In order to produce different Ordram 10G / 10 wt% molinate active ingredient formulations and 10LG / 10 wt% molinate active ingredient formulations containing 0.20 wt% BHT / BHA antioxidant. it needed to be created, which dominates the use, such as opening the bags, and spraying from the airplane. Under these conditions, the volatile constituents in the composition are unbalanced with their vapors in the ambient air, as the ambient air is rapidly expelled and new air is replaced. Therefore, in the laboratory, the concentration of evapotranspiration must be examined in the air stream and in non-static air saturated with the vapors.

During the laboratory study modeling process, a known known constant mass composition is applied to a coarse / "C" / granular glass frit at the bottom of a chromatographic column. The top of the column above the glass frit is 40 cm long and 2.5 cm in diameter. A glass-wool plug I-aza is placed near the upper part of the cylinder and the upper lattice is closed with a neoprene latch comprising a 7 mm long glass tube bent at right angles. Air was passed at a rate of 9 liters / pe.rc up the chromatographic column. The glass wool placed near the top of the column filters the dust particles from the air stream and the glass belt increases the velocity of the leaving a'ram and facilitates sampling. This unit is referred to herein as a degassing pin. Samples are taken from the stream supplied by the aeration unit for 10 seconds and 45 seconds after the air stream is started. The 10 second samples contain more volatile components of the formulation than the 45 second samples. The volatile constituents are diethyl disulfide (DEDS) and diethyl dithiocarbamate (DEDTC).

analysis with sensory evaluation

The aeration strength of the auxiliary current is evaluated by a directional odor analyzer of approximately twenty members. Samples of the stream supplied by the aeration are diluted with clean air to about 1000-fold prior to introduction into the chafing members.

Samples delivered by the aeration are subjected to a clean, odor-free, 200-milliliter sample for sensory evaluation. The injection pistons are removed from the cylinders, which are then placed over a 7 mm tube from the aeration to flush with the current from the aeration unit. After a definite period of time, the cylinder is removed and the injection piston is replaced. The syringes are then placed in a specially designed dynamic gravity meter that dilutes the samples as needed. The gauge accepts up to four syringes at a constant rate, equipped with a four-hole syringe actuator and delivers 200 ml of sample in about 4.6 hours. The currents from each syringe are passed through a short Teflon capillary to a shaker glass mixer and a suction opening. Purified air is added to the aspirator orifice through a standard orifice at a rate of 0.9 liters / pcrc. For a more convenient interpretation of the results, the units resulting from odor evaluation are converted to DEDS units. To accomplish this, a calibration curve is prepared which contains the pure DEDS odor values as a function of the appropriate concentration. The results in equivalent concentration units are summarized in Table I below.

In addition, the gas stream from the aeration is plated by gas chromatography to determine the most odorous constituents, including DEDS and DEDTC. The results of the study are shown in Table II. table.

195 608

Table I

Mint 10 G 10 LG

1. DEDS unit / 10 sec / 144 ¹ / 100-211 / ²

2. DEDS unit / 10 sec / 133 / 94-181 / ²

3. DEDS unit / 45 sec / 190 * / 130-270 / ²

4. DEDS unit / 45 sec / 50 ^ 33-80 / ^{2 1} odor value expressed as DEDS concentration in air ² estimated uncertainty of result / 80% confidence interval /

II. spreadsheet

Sample 10G I0LG 1. DEDS, mg / m ³ , 10 sec 140 118 2. DEDS, mg / m ³ , 10sec 80 43 3. DÉDS, ing / nr ³ , 45 sec 71 61 4. DEDS, mg / m ³ , 45 sec 49 23 5. DEDTC, mg / m ³ , 10 sec 17 14 6. DEDTC, mg / m ³ , 10sec 80 43 7. DEDTC, mg / m ³ , 45 sec 12 10 8. DEDTC, mg / m ³ , 45 sec 7 6

2. péi 'la

Chemical Analysis-Field Study

In the field study of the preparation of 10G and 10LG of Example 1, the amount of the same constituents in the air was determined near the point where the bags containing the formulated composition were opened, whereby samples of the air above the opening of the bags were randomly analyzed. to determine the most odorous creators including DEDS and DEDTC. The results obtained are shown in Fig. 1Π. table.

III. spreadsheet

! Sample 10G 10LG ί 1. DEDS, Mg / m ³ 100 20 I 2. DEDS, μ / ιη ³ 1200 1400 45 3. DEDS, μ / ηι ³ 440 60 Γ 4. DEDTC, pg / m ³ 330 390 1 Ϊ 5. DEDTC, μ / m ³ 130 36 k ! Example 3 50 The Ordram 10G of Example 1 and 10LG / 0.2%

Bag samples (22.5 kg) were prepared from BHA and BHT formulations for experimental use (long storage) and their stability was determined at various intervals. The amount of active substance in the sample was determined by gas chromatography analysis. The results of the 10LG samples are shown in Table IV. The results of the 10G samples are summarized in Table V.

The results are average results determined from samples taken from different bags of the same product θθ.

ARC. spreadsheet

IC

Sample I Elapsed time / day / 0 % By weight of active ingredient 10.6 Second 4.5 10.3 Third 6.0 10.4 4th 8.5 10.4 5th 10.5 10.1 Table V. Sample Elapsed Time / Month / Weight% of active ingredient First 0 10.0 Second 12 7.6

The herbicidal compositions of the present invention are useful for controlling the growth of unwanted vegetation in pre-emergence and post-emergence applications by applying the formulations to the soil before or after emergence, applying it to a flooded field and applying irrigation water to the irrigation system. into the soil. In the latter method, the formulations are added to the irrigation water before being applied to the soil. This method can be applied in all geographical areas, regardless of rain, as it ensures natural rain in the critical state of development of the plant. In a typical application, the active herbicidal agent in the irrigation water is in the range of about 10 to 150 ppm. The irrigation water can be applied with a sprinkler system, in surface furrows or by flooding. Such application is most effective before germination of weed seeds and two days after tillage. The compositions of the present invention are particularly useful in agricultural fields where the environment itself is water, a water-containing material such as soil or a surface subject to frequent rainfall. A preferred area of application of the compositions of the invention is for controlling weeds in flooded rice fields.

By way of example, the compositions of the present invention!

composition is as follows:

S-ethylhexahydro-1H-azepine-1-carbothioate 10.01% Butyl Hydroxyanisole 0.21%

Crude linseed oil 10,0% by weight kaolin 79,8t%

Claims (3)

I. Granular herbicidal composition containing one or more C10-C24 unsaturated aliphatic acid hardened glycerides of the thiolcarbamate derivative or one or more of their glycerides, characterized in that the active ingredient is from 1% to 20% by weight of the composition. ) coated porous particulate material impregnated with a lolycarbamate derivative of the general formula R ¹ is C 1 -C 4 alkyl and R ² and R ³ together form a C 5 -C 7 alkylene group - and the total weight of the composition in the coating 195 638 With reference to 0.1, 0.8% by weight of butylhydroxyanisole, butyl -hydroxytoluene, or a mixture thereof, and the coating comprises from 1% to 30% by weight of the composition. 2. A composition according to claim 1, wherein the active ingredient is a compound of formula I wherein R ^{1 is} a C 2 -C 4 alkyl group and R ² and R ³ together form a C 5 -C 7 alkylene group. 3. A composition according to claim 1 wherein the thiolcarbamate herbicide is S-ethylhexahydro-1H-azepine-1-carbothioate.