IL22825A - Compositions and process for controlling plant growth - Google Patents

Description

. 1'DniHJl |Π3 Τ11Π1»,Ί 'ΊΊ PATENT ATTORNEYS □ ' D J D □ 'DUD OR. REINHOLD COHN |Π3 Tii ni " n · n DR. MICHAEL COHN ISRAEL SHACHTER B Sc. .0.3 103111 "JNTtU' Fit- a 21913 PATENTS AND DESIGNS ORDINANCE SPECIFICATION Compositions and process for controlling plant growth n»ix*i »n^a nn*as nyja I' nm Frai- n I/We PENNSALT CHEMICALS CORPORATION, a corporation of the State of Pennsylvania, of Three Penn Center Plaza, Philadelphia 2, Pennsylvania, U.S.A. do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement :- HERBICIDAL COMPOSITIONS AND PROCESS This invention relates to a process for controlling plant growth and to herbicidal compositions containing a hexafluoroarsenate salt as the active herbicid .

The need for chemical herbicides, and particularly for selective herbicides, is well recognized. While arsenic compounds have been among the agents previously known to have herbicidal action, arsenic compounds in general have not been selective in their action and have adversely affected both crops and weeds so that actual weed control with arsenic compounds, except for soil sterilization, was extremely difficult, if not impossible. It has now been found that hexafluoroarsenates are extremely efficient herbicides, and, in addition, exert selective activity In that they do not adversely affect desirable crops. In accord with this invention, there is provided herbicidal compositions containing salts of hexafluoroarsenates as the active agent, it being understood that the active chemical entity is the hexafluoroarsenate anion, viz. As Fg*".

The herbicidal compositions of the invention are particularly useful as pre- emergent herbicides and will be applied and formulated in the usual manner. The compositions may be used at effective concentrations of active ingredient which will generally range from about 1 to 40 lbs . acre; preferably the concentrations used will be in the range of 2 to 8 lbs ./acre, and such concentrations may be used in pre-emergent applications to give weed control without damage to the desirable crop. Compositions may be formulated as dis-persions in water or as water solutions, with or without wetting agents which will aid in penetration of plant and soil surfaces. Instead of using aqueous systems, organic solvent systems may be employed with the active' agent dispersed in the < liquid carrier.

Composition a may also be prepared as concentrates containing from about 1% to about 90% by weight of active agent for dilution with water for field application. These concentrates may be prepared as aqueous solutions or as dispersions in organic solvent systems, as for example with xylene, toluene, and the like, and suitable emulsifying agents may be added to obtain a dispersion of the active agent.

The fluoroar senates lend themselves readily to spray or drench application in water and for impregnation on granular materials for use in dry application equipment. In this latter application granules may be formulated at concentrations of from about 1% to about 50% active herblcidal ingredient. The granules containing the herbicidal agent are made readily in accordance with previously known procedures simply by spraying an aqueous solution of the active agent onto the inert carrier granule and allowing the granule to dry.

Application is then made by a granular applicator in accord with known methods used in commercial herbicidal applications .

The fluoroareenate salts which are useful in this invention will pre* ferably be selected from acid and the alkali metal salts, the ammonium salts, primary, secondary and tertiary amine salts and quaternary ammonium salts of hexafluoroarsenic acid. That is, the preferred active agents will be those having the chemical formulation M AsFg where M is hydrogen, an alkali metal (such as sodium, potassium, lithium, and the like), an alkaline earth metal (e.g.", barium, calcium, strontium, etc.), ammonium, substituted ammonium as derived from a primary, secondary, tertiary or quaternary amine (e.g. methylamine, ethylamine, dimethylamine, triethyl-amine, octylamine, dioctylamine, dodecylamine, tridecylamine, dimethyl** benzylammonlum and the like) . It will be understood, however, that any with this invention. The salts are most preferred because they are less corrosive than the free acid and are easier to handle and use.

Examples of suitable formulations which may be used in accord with this invention are as follows: I . Aqueous solutions A 1 £ KAsFg 10% 20% 40% Water 90% 80% 60% II . Granular Agent Granules having an active herbicidal concentration of 5, 10 or ¾0% are prepared by impregnating available absorptive substrates (e.g . attapulgite) with one of the herbicide liquid concentrates . A 40% qqueous solution of KAsFg is ideal for spraying onto absorptive granules to make a 5, 10 and 20% concentration on the granule.

III . Organic Solvent Concentrate A. Dibutyla ramonium hexa fluoroar sentate 10% Acetone % B . KAsFg 10% Dlmethyltridecylamlne 12% Diacetone alcohol 73% Surfactant ("Triton" X 161) 5% IV. Aqueous Concentrate (Suspension) HAsFg 10% CaC03 5% Water 85% The use of the formulations and compositions in pre- emergent weed control application on various crops will be carried out in the usual fashion. Pre- emergent weed control involves the application of the chemical to the soil some time prior to the emergence of the crop. Application can be conveniently made at the same time as the seeding operation and most commonly involves use of a sprayer attachment to the planter which applies the diluted chemical on the soil surface immediately after covering the seed. Only a band of the seed row may be treated with the herbicide or the whole area may be treated on a broadcast b asis. The chemical may or may not be mixed with the first one or two inches of soil at the time of this application, using a suitable RototfUer type tool.

The pre- emergent herbicides as employed in this invention possess the necessary properties to be effective in field use. Ideally, it should be possible to place the chemical on the soil surface in the zo of germinating weed seeds which are usually above the zone in which the crop plant has been placed. Small weed seeds usually emerge from only the upper inch of soil.

However, it is impossible under practical conditions to maintain a separation of the chemical and it is therefore necessary for the herbicides to be of the selective type which will control as many undesirable weeds as possible with" ; out significant injury to the crop. This requires unique and highly specific properties in the herbicidal agent, since many of the crop plants are related botanically to weed crops occurring in the same field. The compounds of this invention have these highly selective properties . Furthermore, anU particularly important, is the fact that the compounds of this invention are resistant to degradation by various factors which are present in the soil environment and which will destroy or mitigate herb cidal activity. The herbicides of this invention also have a wide spectrum of weed control which is desirable because most crops can be infested with many species of both grasses and hroadleaf weeds.

The pre-emergent herbicides of this invention are adapted for use on specific crop plants and show a high degree of tolerance to many varieties of crops . This tolerance is shown in all types of soils and under various environmental conditions which change the response of the crop to a chemical. Another ad* vantage of the herbicidal formulations and compositions of this invention is that they show lack of desiccation or injury to the crop and thus they are ueeful for weed control on established turf and other establiehed perennial plantings and may also be used as layby herbicides which are sprayed onto the ground before the crop gets so large that it is impossible or impractical to remove weeds by cultivation in the later stages of the crop's development.

The following examples will serve to further illustrate the Invention: EXAMPLE 1 A ten per cent by weight aqueous solution of potassium hexafluoro-arsenate was sprayed onto a soil surface which had previously been planted with seeds of crops and weeds. The plantings were subjected to greenhouse conditions and were observed periodically. Table 1 which follows indicates the specific data and the results obtained} TAffLE I Pre-emergent Herbicidal Effects of Potassium H exa fluoroar s e ate Per Cent Kill of Weeds Rate Per Acre lbs/ 5 lbs. 2.5 lbs.

Weed: Foxtail 100 100 100 Crabgrass 100 100 100 Lambsquarter 100 100 100 Amaranthus 100 100 100 Wild oats 100 70 100 Per Cent Emergence of Crops Sugar beets 36 48 56 Cotton 70 48 2d Peas 70 44 Soybeans 50 50 60 EXAMPLE 2 A solution of 10% by weight of dibutylaramoniuaa hexafluoroer senate was applied to soil planted with crops and weeds In accord with the procedure of Example 1. The following Table Π gives the specific data and ndicates the results obtained: Pro-emergent Herblcldal Effects of Dibutylammonlum Hexafluoroarsenate Per Gent Kill of Weeds Rate Per Acre lbs. 10 lbs.

Wedd: Foxtail 95 100 Crabgrass 100 100 Lambsquarter 50 100 Amaranthus 85 100 Wild oats 40 70 Per Cent Emergence Crop: Sugar beets 84 20 Gotton 84 70 Peas 100 40 Soybeans 80 . 90 Flax - $5 Corn 90 EXAMPLE 3 Following the procedure of Example 1, an aqueous solution of hexa-fluoroarsenlc acid was sprayed on seeded soil at 2.5 lbs. per acre. Weeds of foxtail, crabgrass, lambsquarter, and amaranthus were effectively controlled, while crops of beets, cotton, peas, soybeans and flax emerged satisfactorily. EXAMPLE 4 The dimethyltridecylamine salt of iexafluoroarsenlc acid was sprayed on emerged crops and weeds at 3 lbs. per acre in a post-emergent application. Both crops and weeds were almost completely killed.

EXAMPLE 5 Following the details of Example 1, soil planted with crops and weeds was sprayed with potassium hexafluoroar senate and observed two weeks later. Weeds of purslane, crabgrass, foxtail, barnyard grass, mj pigweed (Amaranthusj were controlled 100% while crops of onions, tomatoes, and lettuce showed 100% emergence.

The use of ammonium hexafluoroarsenate gave similar results .

EXAMPL£ 6 This example illustrates the use of the hexaf uoroarsenates at very high rates of application for soil sterilization .

A rate of 20 lbs. per acre of AsFg was applied to the soil and S months later the treated soil was planted to weeds and crops and the following results were observed: Foxtail Crabgrass 100 Lambsquarter 100 Amaranthus 100 Wild oats 40 Crop % Emergence Sugar beet 0 Cotton 10 Peas 0 Soybeans 20 Flax 0 The rate of 20 lbs. per acre used above is in contrast to 200 tO S00 lbs. of AsgOg equivalent per acre recommended for one year control of weeds when sodium arsenite is used as a soil sterilant.

EXAMPLE 7 The Bthylamine salt of HAsPg was prepared as an aqueous solution containing the equivalent of 10% HAsFg and was applied to soil planted tQ crops and weeds in accord with procedure of Example 1. At a rate of 2.5 pounds per acre HAsFg equivalent the following results were obtained: Weed. % Kill Foxtail 100 Crabgr se 100 Amaranthus 97 Wild Oats 40 Crop % Emergence Sugar Beets 100 Cotton 60 Peas 99 Soybeans 90 Flax 100 EXAMPLE 8 The tallowamlne salt of HAsFg was prepared to contain the equivalent of 10% HAsFg in diacetone alcohol as the solvent and was applied to soil planted to crops and weeds in accordance with procedure of Example 1. At a rate of 2.5 pounds per acre HAsFg equivalent the following results were obtained: % Kill Crabgrass 100 Foxtail 100 Lambsquarter 80 Amaranthus 100 Wild Oats 80 % Emergence Sugar Beets 36 Cotton 84 Peas 100 Soybeans 100 Flax 100 EXAMPLE 9 The triaraylamine salt of HAsFg was prepared to contain the equivalen of 10% HAsFg in diacetone alcohol as the solvent and was applied to soil planted to crops and weeds in accordance with procedure of Example 1.

At a rate of 2 .5 pounds per acre HAsFg equivalent the following results were obtained: ¥ eed % Kill Foxtail 100 Crabgrass 100 Crop ¾ Emergence Sugar Beets 70 Cotton 84 Peas 55 Soybeans 80 Flax 60 EXAMPLE 10 The calcium salt of HASF5 was prepared by adding finely ground σ C C03 to HAsFg in aqueous media to form CalAsFg)^ . A suspension was obtained and adjusted to contain 10% HAsFg equivalent. This was diluted further -with water and sprayed onto soil planted to crops and weefls in accordance with procedure of Example 1. At a rate of 2.5 pounds per acre HAsFg equivalent the following results were obtained: Weed % Kill Foxtail 100 Crabgrass 100 Lamb squar tor 100 Amaranthus 100 Crop % Emergence Sugar Beets 100 Cotton 60 Peas 100 Soybeans " 90 Flax 100 Additional salts which when used in the above examples give similar results include the dimethylbenzylamfnonium, tetramethylammonium, octadecyl ammonium, barium, and sodium salts .

It will be understood that numerous changes and variations may be made from the above description and examples without departing from the spirit and scope of the inventio .

Claims (1)

1. HAVING NOW particulary described and ascertained the nature of our said invention and in what manner the same is to be we declare that what we claim is compositions comprising a carrier and as a herbicidal agent a Compositions comprising a carrier and as an active herbicide a of formula MAsFg where M is an alkali A composition as in Claim 2 wherein the active agent is Compositions comprising a carrier and as an active herbicide a pound of structure MAsFg wherein M is selected from the group sisting of ammonium and substituted ammonium radicals A composition as in Claim 4 wherein the active herbicide is hexafiuoroarsenate A composition as in Claim 4 wherein the active herbicide is A composition as in Claim 4 wherein the active herbicide ammonium hexafluoroar senate A composition as in Claim 4 wherein the active herbicide is a hexafiuoroarsenate A composition as in Claim 4 wherein the active herbicide is the tallowamine salt of hexafluoroar senic acid Compositions comprising a carrier and as an active herbicide a compound of formula MAsFg wherein is an alkaline earth A composition as in Claim 10 wherein the active agent is calcium Compositions comprising a carrier and acid as an active herbicide The method of controlling unde vegetation which comprises treating plants with a growth affecting amount of a hexafluoroarsenate A method for weed control whioh comprises treating soil prior to emergence of a planted crop a active amount of a compound selected from the class consisting of hexafluoroarsenic acid and its The invention ao Dated this 20th day of 1965 insufficientOCRQuality