SU347967A1 - - Google Patents

Description

The invention relates to chemical means for controlling weeds in crops of cultivated plants.

It is known to use, as gerbiids, various thiol esters of carbamic acid, for example, ethyl thiol carbamic acid ester with different alkyl substituents at the nitrogen atom. These compounds effectively inhibit the growth of weed plants, however some species of the latter are very resistant to them.

It is proposed to use thiol-carbamic acid esters of the general formula as a new selective herbicide.

RI

.-C-n:

II o

R2

where RI and Ra - mean alkyl or alkenyl with the number of carbon atoms not more than 4, and Ri, in addition, can mean hydrogen. The proposed compounds have a high herbicidal activity against weed plants growing in rice crops, for example, against a barnyard and a wetland. They can be applied both before and after the plant exits. These compounds have less phytotoxicity with respect to rice, which allows them to be applied through one or two

weeks after planting the latter.

Depending on the doses used, the compounds of the above general formula can be used as selective herbicides (2.5-5 kg / ha) and as continuous herbicides (20-40 kg / ha).

The forms of application of the proposed compounds are common: solutions, emulsions, suspensions,

powders, pastes or granules. They are prepared by known methods common in the manufacture of preparative pesticides. The content is valid, their substances in preparative forms are within

0.1-95 weight. %, preferably 0.5 to 90 wt. % In order to expand the spectrum of action of these compounds, they can be used in combination with other biologically active substances or fertilizers.

Methods for preparing the proposed compounds are based on the reactions:

a) 2-phenylethylmercaptan (or its mercaptide) with carbamoyl chlorides;

b) 2-phenylethylthiol-carbonic acid chloride with amines;

c) 2-phenylethyl halide with thiol-carbamic acid salts;

d) 2-phenylethylmercaptan with isocyanates. The following compounds of NiN-diisopropyl-2-phenylethylthiolcarbamate are proposed;

L1H-dipropyl-2-phenylethylthiolcarbamate;

N-methyl-N-butyl-2-phenylethylthiol carbamate;

N-butyl-2-phenylethylthiolcarbamate;

L1H-dibutyl-2-phenylethylthiolcarbamate;

L1H-diallyl-2-phenylethylthiolcarbamate;

Table 1

30–50%, 4– plants damaged 50–80%, 5 - full of plant death.

For comparison, known herbicides are used: NiN-dimethyl - benzyldithiocarbamate (compound A); pentachlorophenol. (, compound B); methyl-N- {3,4-dichlorophenyl) carbamate (compound B).,

The test results are presented in table. one.

Example 2. Post-harvest application. In the soil on which the plants grow in the 3-leaf stage, ezhovnya seeds are sown, covered with a layer of soil 5 mm thick and irrigated with water. 8 days after sowing, the water covering the soil to a depth of 6 cm is treated with the proposed compounds in doses of 6.3 and 1.5 kg / ha, reducing the water level to 2-3 cm (during the day) and two weeks after processing the wire t account for herbicidal activity, assessing it on a scale of five, similar to Example 1.

For comparison, the same known herbicides (compounds A, B and C) are used. - .: The results of the test are presented ;: in table. 2

 Table 2

A: monochloria, rotala, false full-color. Etc.

Example 1. Riplings of rice in the stage, 3-4 leaves are transplanted into the prepared soil and after they take roots in this soil they sow the seeds of ezhovny, broadleaf weeds and bog grass. Then, the soil is treated with the proposed herbicides in doses of 5, 2.5 and 1.25 kg / ha and three, weeks after processing, the herbicidal activity is taken into account, assessing it in a tibalial scale: O - no damage to plants, 1 slight damage to plants 2-plants are damaged by 30%, 3 - plants are damaged Example 3. Pre-emergence application. Seeds of experimental plants are sown in prepared soil and treated with compound in doses of 20, 10, 5, 2, 5 and 1.25 kg / ha.

Accounting for herbicidal activity was carried out 3 weeks after treatment and evaluated on a five-point scale: O — no effect, 1 — slight damage to the silt and plant growth slowdown, 2 — distinct damage. The results of the experiments indicate a higher herbicidal activity of the proposed compounds compared to known herbicides of this group. In addition, they have a better selectivity for cultivated plants.

Subject invention

The use of thiol-carbamic acid esters of the general formula

growth or growth retardation, 3 - great damage or only 50% of seedlings, 4 - partial death of plants or only 25% of seedlings, 5 - full death of plants.

A known herbicide (compound A) is used for comparison.

results

tests are presented in table. 3

Table 3

ten

.RI

SI2.C H25-C- “:

li R

where Ri and Ra - mean alkyl or alkenyl, with the number of carbon atoms not more than 4, and Ri, in addition, mean hydrogen as a herbicide.