FORM 2
THE PATENTS ACT 1970
(39 of 1970) &
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See Section 10; Rule 13)
1.TITLE OF THE INVENTION: A novel process for preparation of Triclopyr-butoxyethyl ester from sodium salt of 3,5,6-trichloro-2-pyridino1 and 2-butoxyethyl chloroacetate.
2. APPLICANT(S)
(a) NAME: Excel Crop Care Limited
(b) NATIONALITY: An Indian Company
(c) ADDRESS:
184-87, Swami Vivekanand Road, Jogeshwari, Mumbai 400 102, Maharashtra, India.
(a) NAME: C.C. Shroff Research Institute
(b) NATIONALITY:
(c) ADDRESS:
13/14 Aradhana Industrial Development Corporation NearVirwani Industrial Estate Goregaon (East), Mumbai 400 063, Maharashtra. India
(a) NAME: Aimco Pesticides Limited
(b) NATIONALITY: An Indian Company
(c) ADDRESS:
"Akhand Jyoti", 8th Road, Santa Cruz (East), Mumbai - 400005, Maharashtra. India.

3. PREAMBLE TO THE DESCRIPTION:
The following COMPLETE specification particularly describes the nature of this invention and the manner in which it is to be performed.

A novel process for preparation of Triclopyr-butoxyethyl ester from sodium salt of 3,5,6-trichloro-2-pyridinol and 2-butoxyethyl chloroacetate.
FIELD OF INVENTION
This invention relates to a process for preparation of Triclopyr-butoxyethyl ester from sodium salt of 3,5,6-trichloro-2-pyridinol and 2-butoxyethyl chloroacetate. More particularly, the present invention relates to a process for preparation of Triclopyr-butoxyethyl ester wherein the reaction between sodium salt of 3,5,6-trichloro-2-pyridinol and 2-butoxyethyl ester of chloroacetic acid is carried out using a catalyst in absence of solvent.
BACKGROUND AND PRIOR ART
Triclopyr-butoxyethyl ester is a selective systemic herbicide used for control of woody and broadleaf weeds.
A method for preparation of triclopyr-butoxyethyl ester has been reported in Indian patent 197707 wherein triclopyr-butoxyethyl ester is obtained in 82% yield and 92% purity by reacting sodium 3,5,6-trichloropyridinate with 2-butoxyethyl chloroacetate in a solvent medium in presence of a phase transfer catalyst, removing solvent by distillation and distilling triclopyr butoxyethyl ester under vacuum. This method involves carrying out reaction in presence of solvent which consumes more energy and results in greater losses of solvent during reaction than if reaction would have been carried out without

solvent. Moreover, the yield is low and it requires distillation of not only solvent, but also the product to achieve the desired purity of the product.
The inventors of present invention have developed a process for preparation of triclopyr-butoxyethyl ester wherein the reaction between sodium salt of 3,5,6-trichloro-2-pyridinol and 2-butoxyethyl ester of chloroacetic acid is carried out in presence of catalyst but without solvent, thereby avoiding extra consumption of energy and solvent losses during reaction. The process of present invention though requires solvent for separation of the product after reaction, the quantity required thereof is very less compared to the process of prior art.
OBJECTS OF INVENTION
The object of present invention is to provide an efficient process for preparation of Triclopyr-butoxyethyl ester by reaction of 2-butoxyethyl ester of chloroacetic acid with sodium salt of 3,5,6-trichloro-2-pyridinol in presence of a catalyst, which obviates the need to carry out reaction in presence of organic solvent, and thereby avoiding solvent losses during the reaction and reducing energy consumption.
Another object of invention is to provide a process for preparation of Triclopyr-butoxyethyl ester in good yield compared to the process of prior art, without need for distillation of the product.

DETAILED DESCRIPTION OF INVENTION
For preparation of Triclopyr-butoxyethyl ester, 2-butoxyethyl ester of chloroacetic acid is reacted with sodium salt' of 3,5,6-trichloro-2-pyridinol in presence of tetrabutylammonium bromide which is an inexpensive well known phase transfer catalyst used extensively.
In the process of present invention, the reaction is carried out without organic solvent, in presence of the catalyst, thereby avoiding extra consumption of energy and solvent losses.
The process of present invention though requires solvent for separation of the product after reaction, the quantity required thereof is very less compared to the process of prior art.
Typically, in the process of present invention, 2-butoxyethyl chloroacetate, sodium salt of 3,5,6-trichloropyridinol and catalyst are mixed and the mixture is maintained at 55-65°C under stirring. The resulting product is washed with hot water, filtered and extracted with solvent. The organic layer is separated and dried over anhydrous sodium sulfate and optionally decolorized with silica gel. The solvent is then removed by vacuum distillation to obtain Triclopyr-butoxyethyl ester in 90-94% yield. The product may be extracted in any suitable solvent and the solution of Triclopyr-butoxyethyl ester may be used directly for preparing formulation.

EXAMPLE-1
0.445 moles 2-butoxyethyl chloroacetate was taken in a reactor which was provided with a mechanical stirrer, thermometer pocket and a condenser. 0.445 moles sodium salt of 3,5,6-trichloro-2-pyridinol and 4.5 g. of tetrabutylammoniurn bromide were added to it. The reactor was placed in a water bath to maintain temperature of the reaction mixture at 55°C under constant stirring. After reaction, the amount of 2-butoxyethyl chloroacetate present in the mixture was found to be less than 0.5%. The resultant product was washed with 200 ml hot water and was filtered. The product was then extracted with 200 ml hexane. The organic layer was separated, dried over anhydrous sodium sulfate and decolorized with silica gel. Hexane was removed by vacuum distillation to obtain Triclopyr-butoxyethyl ester with 90% yield and 91% purity.
EXAMPLES-2 8s 3
The process as described in Example-1 above was repeated except the molar ratio of reactants[sodium salt of 3,5,6-trichloro-2-pyridinol : 2-butoxyethyl chloroacetate] was taken as given in the following table. The results obtained are also given therein.

Example No. Mole Ratio
Na-TCP:2-butoxyethyl chloroacetate Yield
2 1:1.05 92.00%
3 1:1.10 94.20%

CLAIMS:
1. A process for preparation of Triclopyr-butoxyethyl ester
comprising steps of:
(i) reacting 2-butoxyethyl chloroacetate with sodium salt of 3,5,6-
trichloropyridinol in presence of a catalyst;
(ii) washing the resultant product with water;
(iii) extracting the product with a solvent;
(iv) separating the organic phase and optionally drying it with a
drying agent &/or decolorizing;
(v) removing the solvent by distillation.
2. A process as claimed in claim 1, wherein the molar ratio of sodium salt of 3,5,6-trichloropyridinol to 2-butoxyethyl chloroacetate is 1 : (1-1.5).
3. A process as claimed in any of the claims 1 or 2, wherein the catalyst used is tetrabutylammonium bromide.
4. A process as claimed in any of the claims 1-3, wherein the catalyst is used in the range of 0.5 - 5.0 mole% based on the moles of sodium salt of 3,5,6-trichloropyridinol.
5. A process as claimed in claim 1, excluding any of the steps (ii) or (v).