DE2520165A1 - HERBICIDE - Google Patents

Description

Herbicide The invention relates to a herbicide which contains a substituted oxirane compound of the general formula: wherein X is halogen, Z is hydrogen, halogen, cyano or C14-alkyl, R and R 'independently of one another are hydrogen, halogen, cyano, nitro, C1 4 -alkoxy, trifluoromethyl, benzyloxy and / or C1 4-alkyl, with with the proviso that - when R 'denotes hydrogen - R contains a meaning other than hydrogen. These compounds are particularly useful in preventing seeds from sprouting undesirable plants and controlling harmful weeds.

The preferred compounds are 2- (m-chlorophenyl) -2- (2,2,2-trichloroethyl) oxirane and 2- (m-bromophenyl) -2- (2,2,2-trichloroethyl) oxirane. With low application quantities are certain of the compounds as selective herbicides in crops such as corn, Cotton, soybeans or rice.

As used herein, the term "alkyl" means saturated monovalent aliphatic radicals including straight chain and branched chain radicals. Examples are methyl, ethyl, propyl, isopropyl, butyl and sec-butyl. the The term "alkoxy" as used herein includes straight chain and branched chain ones Radicals such as methoxy, ethoxy, propoxy, isopropoxy and butoxy. The here The term "halogen" as used means bromine, chlorine, fluorine or iodine.

The substituted oxirane compounds used according to the invention are generally oils or crystalline solids at room temperature which are soluble in the usual organic solvents, such as, for example, 1,2-dichlorobenzene, methylene chloride or chloroform. They are made by reacting substituted styrene compounds of the general formula: wherein R, R ', X and Z have the meanings given, obtained with a percarboxylic acid easily. Representative and suitable percarboxylic acids which can be used to prepare the substituted oxirane compounds are, for example, peracetic acid, trifluoroperacetic acid and perbenzoic acid. Buffered solutions of the acid starting materials are preferably used, which are prepared using a buffering agent such as sodium acetate or sodium benzoate.

In carrying out the reaction, the starting percarboxylic acid compound dropwise or in portions over 5 to 10 minutes to the substituted one Given styrene starting compound. Although the amounts of starting compounds used are not critical, the reaction generally consumes the starting compounds in the ratio of 1 mole of the substituted styrene starting compound to 1 or more Moles of the starting percarboxylic acid compound. A suitable ratio of the starting compounds is 1: 1 to 1: 6 (substituted styrene: percarboxylic acid). The application of the Output connections in a molar ratio of about 1: 4 preferred. The reaction is allowed to proceed at temperatures of 20 to 40 ° C and preferably carried out at room temperature. The pressure is not critical and is usually maintained at ambient atmospheric pressure.

The reaction mass is held for a sufficient period of time, that practically a completion of the reaction is guaranteed, what in general 12 to 20 hours or more. The recovery of the product from the reaction mass is achieved by conventional means. Typically, for example, the reaction mass washed with water and neutralized with a base, e.g. sodium carbonate, before it is evaporated to dryness under reduced pressure.

The desired properties of the agents according to the invention are the peculiar to pure connections. If highly selective properties are desired, then the purified compounds are preferred. For many uses, in particular however, in those where cost considerations play the main role, can also Incompletely purified products are used as the by-products of the reaction are often not annoying.

The substituted styrene compounds used as starting materials can be prepared by known or analogous methods. Comparisons e.g. U.S. Patents 3,391,203 and 3,336,401.

The invention is illustrated in the examples.

Example 1 A buffer solution of 40% peracetic acid (24 ml; 0.160 Mol) and sodium acetate trihydrate (2.0 g; 0.025 mol) were added dropwise with stirring to p-nitro - (2,2,2-trichloroethyl) styrene (12.0 g; 0.043 mol), dissolved. in 75 ml of methylene chloride, given. The addition was carried out over the course of 5 to 10 minutes and at a temperature of 25 to 35 ° C. After the addition, the reaction mass was at for about 16 hours a temperature of about 350C for essentially complete reaction to ensure.

After completion of the reaction, the reaction mass was washed with water, to remove water soluble impurities, and neutralized with sodium carbonate. The reaction mass was washed again with water over anhydrous sodium sulfate dried and concentrated to dryness by rotary evaporation. 2- (p-nitrophenyl) -2- (2,2,2-trichloroethyl) oxirane was obtained as a yellow crystalline solid. the Recrystallization from chloroform gave a purified product as white Plates with a mp of 113-114.5 ° C.

Elemental analysis: Calculated for C10H8Cl3NO3 (%): C 40.5 H 2.7 N 4.7 Found () C 40.1 H 2.7 N 4.7.

Other representative examples are shown in the table below indicated for products according to the invention.

Table I Identity of the compound Properties R R X Z H 3r Cl Cl 25 nD 1.5735 (88% pure) H. CF3 Cl Cl bp 86 to 880C Cl Cl Cl Cl bp 75 ° C; 0.5 mm Hg H Cl Cl Cl nD25 1.5604 (95% pure) H CH3 Cl Cl bp 970C H CH3O Cl Cl bp 980C H CH3CH20 Cl Cl n25 1.5475 (90% pure) H C6H5CH2 ° Cl Cl nD25 1.5703 (61% pure) Cl H Cl Cl bp. 800C Br H Cl Cl m.p. 43.5 to 44.50C The herbicidal activity can be found in the way that one can visualize a plant structure with the compounds brings into contact what is either in advance or on the trained plants can happen. The pre-treatment can be carried out in two ways, viz on the one hand by applying the compounds to the surface of the earth or on the other hand by working the compounds into the surface layer of the earth.

When the germinating seeds and the emerging seedlings of many Earth plant species are brought into contact with agents that contain one of the oxirane compounds contain in sufficient doses that 1.12 to 56 kg / ha of active ingredient are supplied, then there may be permanent inhibition of the growth of such seeds and seedlings can be obtained.

With selective treatment methods of plants and / or their locations by a preliminary check of the germinating seeds utd seedlings of many undesirable Plants, especially of small-sown grasses, in places with the seeds are planted by desired broad-leaved plants or in which the growth is maintained by such plants, the application of the invention has Agents which contain certain of the oxirane compounds in such amounts that 0.0336 up to 0.56 kg / ha have been found to be satisfactory.

The use of larger dosages in soil plants and / or theirs Locations controlled the growth of germinating seeds from all species including inclusion of broad-leaved plants and grasses. With selective treatment depends the exact dosage used depends on the stability of the broad-leaf crops or their seeds versus the particular oxirane composition that is used, and related factors.

It has also been shown that means that certain of the oxirane compounds in dosages of 250 to 4000 or more parts by weight per million parts of the Finished treatment agents contain, to be effective to the growth of trained Control plants of many plant species. In many cases, the application leads of agents containing certain oxirane compounds in amounts of 250 to 1000 parts by weight contained per 1 million parts by weight of the treatment agent, to a selective one Follow-up control of many undesirable plant species, especially small-sown ones Grasses in places allowing the growth of trained plants the desired crops, e.g. of cotton, maize, cultivated rice and white winter wheat, to chat.

The exact dosage supplied by the means in each individual case depends on the type of plant, the growth stage and the hardness as well as on the Part of the plant exposed to the pesticidal agent. Other factors like e.g. weather conditions and possible decomposition of the agents and those contained therein Oxirane compounds due to the action of bacteria and other earth organisms that optionally the plant, the plant part and / or the locations of the means free must also be considered. Although thus the application of low amounts of the active compound per hectare for good control of one light infestation with weeds that grow in poor conditions is sufficient can be, application rates of 5.6 to 11.2 kg / ha of the active ingredient compound required for good control of a dense infestation of hard weeds which grow under favorable conditions.

Agents that contain an oxirane compound and a liquid or solid Contain carriers can be prepared by known methods. Good growth suppressants Results can be obtained when a carrier material is used in relatively low, however, effective amounts are used.

In general, however, the best results are obtained when one either has a surfactant dispersant in a sufficient one Amount that the oxirane compound is emulsified with water as a carrier, e.g. Amount from 0.1 to 15% by weight based on the total Treatment material, or a finely divided carrier solid in an amount from 40 to 99.5% by weight, based on the total treatment material.

The concentration of the oxirane compound in liquid preparations, that are used to deliver the desired dosage is generally 0.0001 to 50% by weight, although in some cases concentrations are suitable as high as 90% by weight can be used. In finely divided solid carrier preparations the concentration of the oxirane compound can be 0.1 to 60% by weight. In preparations, which are used as concentrates can contain the oxirane compound in one concentration from 5 to 98% by weight are present.

Liquid preparations containing the desired amount of the active ingredient, can be prepared by putting the oxirane compound in an organic liquid Carrier dissolving or by placing the oxirane compound in water with or without the aid a suitable surfactant dispersant such as an ionogenic one or nonionic emulsifier, dispersed.

In the production of dust preparations, the active ingredient is in or on a finely divided solid carrier, such as clay, talc, chalk, plaster of paris, bentonite, Fuller's earth, attapulgite, and the like, dispersed.

Example 2 Separate aqueous preparations were prepared as follows: the 2- (m-bromophenyl) -2- (2,2,2-trichloroethyl) oxirane, 2- (p-chlorophenyl) -2- (2,2,2-trichloroethyl) oxtrane, 2- (m-nitrophenyl) -2- (2,2,2-trichloroethyl) oxirane and 2- (p-bromophenyl) -2- (2,2,2-trichloroethyl) oxirane contained.

4 parts by weight of the respective compound, 0.08 part of sorbitol trioleate, and 0.02 part of a Sortbitmonooleatpolyoxyäthylenderivats were in 40 ml of acetone dispersed, creating a concentrate preparation in the form of a water-dispersible Liquid containing the oxirane compound was prepared.

Portions of these individual concentrate preparations were separated into Water dispersed, whereby aqueous preparations were made, the 0.527 g / l oxirane compound contained.

The aqueous preparations were then used to treat seed beds a good agricultural soil used, which prepared and with the Seeds of various types of plants had been planted. In the treatment a preselected amount of each preparation was placed on separate seed beds applied as earth irrigation to a substantially uniform dosage to be supplied, which have a concentration of 1.12, 2.24 and 5.6 kg / ha of the oxirane compound was equivalent. Additional seed beds were made in a similar manner to those indicated Plant species planted, however, were left untreated to serve as control samples to serve.

After about 2 weeks, the seed beds were examined to determine what control of the growth of the seeds had been obtained. The results are compiled in Table II.

Table I Pre-run control of seed germination at different application rates, % (in kg / ha) seed types 2 - (- bromophenyl) - 2- (p-bromophenyl) - 2- (m-nitrophe- 2- (p-chlorophenyl) -2- (2,2,2-trichloro- 2- (2,2,2-trichloro- nyl) -2- (2,2,2- 2- (2,2,2-trichloroethyl) oxirane ethyl) oxirane trichloroethyl) - ethyl) oxirane 1.12 2.24 5.6 1.12 2.24 5.6 oxirane 1.12 2.24 5.6 1.12 2.24 5.6 goosefoot (Amaranthus spp.) 95 100 100 50 50 90 85 95 95 50 100 100 Fingergrass (Digitaria spp.) 0 100 100 0 100 100 95 100 100 95 100 100 Sudan grass (Sorghum halepense) 95 95 100 95 95 95 70 85 95 95 100 100 Barn yard grass (Echinocloa crusgalli) 95 95 95 95 95 95 50 50 95 95 95 100 Oat grass (Avena fatua) 100 100 100 95 95 90 40 50 80 100 100 100 Cultivated rice (Zizania aquatica) - 100 100 - 100 100 100 95 100 100 100 100 yellow foxtail (Setaria glauca) 100 100 95 0 0 80 100 - - 95 95 95 example 3 As in Example 2, aqueous formulations were prepared which had one of the following Compounds contained: 2- (m-tolyl) -2- (2,2,2-trichloroethyl) oxirane; 2- (m-methoxyphenyl) -2- (2,2,2-trichloroethyl) oxirane} 2- (m-chlorophenyl) -2- (2,2,2-trichloroethyl) oxirane; 2- (m-fluorophenyl) -2- (2, 2, 2-trichloroethyl) oxirane; 2- (3,4-dichlorophenyl) -2- (2,2,2-trichloroethyl) oxirane; 2- (m-ethoxyphenyl) -2- (2.2, 2-trichloroethyl) oxirane and 2- (m- (benzyloxy) phenyl) -2- (2,2,2-trichloroethyl) oxirane.

These formulations were used in a similar manner to the pre-treatment used by different plant species.

2- (m-Tolyl) -2- (2,2,2-trichloroethyl) oxirane gave essentially one full control of goosefoot, finger grass, sudan grass, barn grass, oat grass and yellow foxtail, if the seeds of these plant species with preparations in Were brought into contact that contained the active ingredient in sufficient quantities that a dosage of 2.24 kg / ha was applied.

2- (m-Methoxyphenyl) -2- (2,2,2-trichloroethyl) oxirane gave essentially one Complete advance control of goosefoot, fingergrass, Sudan grass and barn yard grass and 2- (m-Athoxyphenyl) -2- (2,2,2-trichloroethyl) oxirane gave one essentially full control of finger grass, sudan grass, barn grass and oat grass, when the seeds of such plant species are brought into contact with preparations were, which contained the respective active ingredients in sufficient quantities that one Dosage of 2.24 kg / ha was fed.

2- (m- (Benzyloxy) phenyl) -2- (2,2,2-trichloroethyl) oxirane gave an im essential full control of goosefoot, finger grass, barn grass, oat grass and yellow foxtail, if the seeds of these plant species with sufficient Amount of preparation were brought into contact that a dosage of 2t, 4 kg / ha was added.

Treatment of the seeds of goosefoot, fingergrass, sudan grass and oat grass with a preparation containing 2- (3,4-dichlorophenyl) -2- (2,2,2-trichloroethyl) oxirane, in an amount of 2.24 kg / ha similarly gave a practically complete one Control of these species.

An essentially complete advance control of fingergrass, Sudan grass, barn grass, oat grass and yellow foxtail has also been applied by of preparations containing 2- (m-chlorophenyl) -2- (2,2,2-trichloroethyl) oxirane or 2- (m-fluorophenyl) -2- (2,2,2-trichloroethyl) oxirane contained, achieved at dosage levels of 0.27 and 0.56 kg / ha.

Example 4 As in Example 2, an aqueous preparation was prepared, which contained 2 - ($, α, α-trifluoro-m-tolyl) -2- (2,2,2-trichloroethyl) oxir & n. This preparation was then used as in Example 2, with the exception that Lower concentrations of the oxirane compound were used in the preparation.

In the following Table III, the percentage Kon-.

Try different types of plants at the indicated dosage of 2- (α, α, α-trifluoro-m-tolyl) -2- (2,2,2-trichloroethyl) oxirane, that was supplied by the preparation, compiled.

Table III Seed germination control,% (in kg / ha) seed type 0.0336 0.078 0.145 0.27 Goosefoot 0 30 50 100 Finger grass 60 75 100 100 Sudan grass 0 80 100 100 barn grass 50 95 95 95 oat grass 30 85 95 95 yellow foxtail 30 0 95 100 cotton O 0 0 0 corn O 0 0 90

Claims (2)

Patent claims 1. Herbicide, characterized in that it is a substituted oxirane compound of the general formula: where X is halogen, Z is hydrogen, halogen, cyano or C1 4 -alkyl, R and R 'independently of one another are hydrogen, halogen, cyano, nitro, C1 4 -alkoxy, trifluoromethyl, benzyloxy and / or C1-4-alkyl , with the proviso that - when Rt is hydrogen - R has a meaning other than hydrogen, contains. 2. Herbicide according to claim 1, characterized in that it is e k e n n -z e i c h n e t that it is 2- (p-bromophenyl) -2- (2,2,2-trichloroethyl) oxirane or 2- (m-chlorophenyl) -2- (2,2,2-trichloroethyl ) contains oxirane.