FORM 2
THE PATENTS ACT, 1970
As amended by the Patents (Amendment) Act, 2002
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
TITLE
A process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines
APPLICANTS
Godrej Agrovet Limited, Pirojshanagar, Eastern Express Highway, Vikhroli (East), Mumbai 400 079, Maharashtra, India, an Indian Company
INVENTORS
Under Section 28(2)
Dr Naik Parag Vilas, Iyer Ramaswamy, Dr Ramraj Velaswamy Munuswamy, Dr Vyas Brahmanand Ambashankar, Dr Mistry Keki Bamanshaw and Godrej Nadir Burjor, all of Godrej Agrovet Limited, Pirojshanagar, Eastern Express Highway, Vikhroli (East), Mumbai 400 079, Maharashtra India, all Indian Nationals The following specification particularly describes the nature of this invention and


the manner in which it is to be performed


FIELD OF INVENTION
This invention relates to a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines of the Formula I:

wherein X is a halogen atom such as fluoro, chloro, bromo or iodo and M is an alkali metal ion such as sodium or potassium.
PRIOR ART
Herbicidal compositions of phenylthiopyrimidines of the Formula I or their salts are reported. They possess excellent herbicidal activity against

perennial and annual weeds and have at the same time a high level of safety to the crop plants. The surfactants and dispersing agents used in the preparation of the above compositions are reported to be alcohol sulfuric acid ester, alkyl aryl sulfonate, lignin sulfonate, polyoxyethylene glycol ether, polyoxyethylene alkyl aryl ether or polyoxyethylene sorbitol mono-alkylate (US Patent No 4932999). Such surfactants and dispersing agents have high persistence in the environment thereby leading to environmental problems.
OBJECTS OF INVENTION
An object of the invention is to provide an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which has improved activity on weeds.
Another object of the invention is to provide an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which has low persistence in the environment and is, therefore, environment friendly.

Another object of the invention is to provide an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which is economical.
Another object of the invention is to provide an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which is stable during storage.
Another object of the invention is to provide a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which has improved activity on weeds.
Another object of the invention is to provide a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which has low persistence in the environment and is, therefore, environment friendly.
Another object of the invention is to provide a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which is economical.

Another object of the invention is to provide a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which is stable during storage.
Another object of the invention is to provide a process for the preparation of an aqueous emulsifiable herbicidal formulation of phenylthiopyrimidines, which is simple, easy and convenient to carry out.
Another object of the invention to provide a method of controlling weeds using the above aqueous emulsifiable herbicidal formulation.
DESCRIPTION OF THE INVENTION
According to the invention there is provided an aqueous emulsifiable herbicidal formulation comprising 5 to 45% by weight of phenylthiopyrimidines of the Formula I


Formula I wherein X is a halogen atom such as fluoro, chloro, bromo or iodo and M is an alkali metal ion such as sodium or potassium in combination with a mixture of 15 to 50 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 40 to 80 % by weight of water
Preferably, the aqueous emulsifiable herbicidal formulation comprises 10 % by weight of phenylthiopyrimidines in combination with 25 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 65 % by weight of water.
According to the invention there is also provided a process for the preparation of an aqueous emulsifiable herbicidal formulation comprising mixing 5 to 45% by weight of phenylthiopyrimidines of the Formula I


wherein X is a halogen atom such as fluoro, chloro, bromo or iodo and M is an alkali metal ion such as sodium or potassium with a mixture of 15 to 50 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 40 to 80% by weight of water.
Preferably, the process comprises mixing 10 % by weight of phenylthiopyrimidines with 25 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 65 % by weight of water.
Preferably, the phenylthiopyrimidines is sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoate.

The formulation of the invention is diluted with water in the volume ratio 1:200 to 1:1000, preferably 1:500, prior to applying or spraying on weeds.
The following experimental examples are illustrative of the invention but are not limitative of the scope thereof:
Example 1
10 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of polyoxyethylene alkyl aryl ether and calcium alkyl benzene sulfonate in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.

Example 2
10 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of sodium lauryl sulfate and polyoxyethylene alkyl aryl ether in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 3
10 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of alkyl trimethyl ammonium bromide and ethoxylated sorbitan ester in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 4
10 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of sodium lauryl sulfate and ethoxylated sorbitan esters in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively .

Example 5
10 % by weight sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of fatty acid esters and ethoxylated sorbitan esters in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 6
10 % by weight of sodium 2~chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate was mixed with 25 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratios 25:75, 50:50 and 75:25 and 65 % by weight of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 7
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 % and 50 % by weight of polyoxyethylene alkyl aryl ether and calcium alkyl benzene sulfonate in the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively .

Example 8
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 % and 50 % of sodium lauryl sulfate and polyoxyethylene alkyl aryl ether in the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 9
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 % and 50 % of alkyl trimethyl ammonium bromide and ethoxylated sorbitan esters in the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 10
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 % and 50 % of sodium lauryl sulfate and ethoxylated sorbitan esters in the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.

Example 11
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 % and 50 % of fatty acid esters and ethoxylated octyl phenol in the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under stirring so as to obtain three emulsifiable formulations a, b and c, respectively.
Example 12
5 %, 10 % and 15 % by weight of sodium 2-chloro-6-(4,6-
dimethoxypyrimidin-2-ylthio) benzoate were mixed with 10 %, 30 %
and 50 % of ethoxylated lauryl alcohol and ethoxylated octyl phenol in
the weight ratio 25 : 75 and 85 %, 60 % and 35 % of water under
stirring so as to obtain three emulsifiable formulations a, b and c,
respectively.
The efficacy of the formulations of Examples 1 to 12 was studied on weeds namely Trianthema portulacastrum (TP), Chenopodium album (CA), Parthenium hysterophorus (PH), Cyperus rotundus (CR) and Cyperus esculentus (CE). Seeds of TP, CA and PH and tubers of CR and CE were placed on surface of soil (area = 500 sq. cm) contained in pots and were covered with soil of thickness 0.75 to 1.25 cm. The seedlings

were raised in a green house under normal growing conditions. The temperature ranged 25 to 35 °C under normal day length conditions. When the seedlings were 14 days old, the formulations diluted with water in the volume ratio 1:500 were sprayed at the rate of 500 litre per hectare. The active ingredient applied was 62.5 g per hectare. The phyto¬toxicity evaluation was conducted two weeks after treatment as shown in the following Tables:
Ratings 1 -10 in the Tables denote the degrees of phytotoxicity. 1 denotes no phytotoxicity whereas 10 denotes highest phytotoxicity (complete mortality).

Table 1 and 2 show that mortality rate of the weeds sprayed with the herbicidal formulations of examples 6 and 12 of the invention was much higher as compared to the mortality rate of the weeds sprayed with the other formulations irrespective of whether the weight ratios of the surfactants remained the same or varied. The formulations of the invention were thus found to achieve improved mortality rate of the weeds thereby establishing the higher penetration of the formulations into the weeds and consequent higher absorption of the formulations by the

weeds. It also establishes that the formulations of the invention offer reduced surface tension and good wettability to the weeds.
Ethoxylated lauryl alcohol and ethoxylated octyl phenol have low persistence in the environment. Therefore the formulations of the invention have low persistence in the environment and are, therefore, environment friendly. Both the above surfactant compounds are cheap and easily available thereby rendering the formulation of the invention economical. The process for preparation of the formulation of the invention is simple, easy and convenient to carry out. The formulations of examples 6 and 12 were stored for 24 months and were found to be stable at the end of that period.

We claim:
1. A process for the preparation of an aqueous emulsifiable herbicidal formulation comprising mixing 5 to 45% by weight of phenylthiopyrimidines of the Formula I

wherein X is a halogen atom such as fluoro, chloro, bromo or lodo and M is an alkali metal ion such as sodium or potassium with a mixture of 15 to 50 % by weight of ethoxylated lauryl alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 40 to 80 % by weight of water,
2. A process as claimed in claim 1 comprising mixing 10 % by weight of phenylthiopyrimidines with 25 % by weight of ethoxylated lauryl

alcohol and ethoxylated octyl phenol in the weight ratio of 25 : 75 to 75 : 25 and 65 % by weight of water.
3. A process as claimed in claim 1 or 2, wherein the
phenylthiopyrimidine is sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-
ylthio) benzoate.
wherein X is a halogen atom such as fluro, chloro, bromo or iodo and
4. A process for the preparation of an aqueous emulsifiable herbicidal
formulation comprising phenylthiopyrimidines of the Formula I


M is alkali metal ion such as sodium or potassium, substantially as herein described particularly with reference to Examples 6 and 12.
Dated this 26th day of April 2004