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 Process for Preparation of Triclopyr-Butoxyethyl Ester from Triclopyr and 2-Butoxyethanol
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 Near Virwani 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 PROCESS FOR PREPARATION OF TRICLOPYR-BUTOXYETHYL ESTER FROM TRICLOPYR AND 2-BUTOXYETHANOL
FIELD OF INVENTION
This invention relates to a process for preparation of Triclopyr-butoxyethyl ester by reaction of Triclopyr and 2-butoxyethanol in presence of a catalyst.
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. In this method, the yield and purity of the product obtained are low.
Thus, there is a need to develop a method of preparation of Triclopyr-butoxyethyl ester in good yield and purity. The inventors of present invention have developed a process for preparation of Triclopyr-butoxyethyl ester from Triclopyr and 2-butoxyethanol in >90% yield and >99% purity.

OBJECTS OF INVENTION
The object of present invention is to provide an efficient process for preparation of Triclopyr-butoxyethyl ester from Triclopyr and 2-butoxyethanol.
Another object of invention is to provide an efficient process for preparation of Triclopyr-butoxyethyl ester with good yield and purity.
DETAILED DESCRIPTION OF INVENTION
Triclopyr-butoxyethyl ester is prepared by reaction of triclopyr and 2-butoxyethanol in toluene in presence of a catalyst. During the reaction, water is removed with the help of dean & stark arrangement. Catalyst is removed by washing the reaction mass with cold water. Water washings are extracted with toluene in order to recover fraction of product dissolved therein. The organic layers are combined and dried over anhydrous sodium sulfate. The solution of product thus obtained can be optionally decolorized with silica gel. The solvent is then removed by distillation under vacuum to obtain triclopyr-butoxyethyl ester with >99% purity.
EXAMPLE-1
In a reactor equipped with a mechanical stirrer, thermometer pocket, dean & stark and reflux condenser, 0.384 moles of triclopyr in 240 ml toluene were taken. 0.411 moles of 2-butoxyethanol was added. 2.0 g. of p-toluene sulfonic acid catalyst was added. The mixture was

heated in an oil bath to reflux temperature i.e., 110-112°C for three hrs. Water during the reaction was removed by dean 8B stark arrangement. The reaction mass was cooled to room temperature and was washed with 150 ml cold water. The washings were extracted with 75 ml toluene. Two organic layers were' combined, dried over anhydrous sodium sulfate and decolorized with silica gel. Solvent was removed by vacuum distillation to get triclopyr-butoxyethyl ester in 93.13% yield and >99% purity.
EXAMPLE-2
The process as described in Example-1 above was repeated except the catalyst used was 2.0 g methanesulfonic acid. The product Triclopyr-butoxyethyl ester was obtained with 90.89% yield and 99.5% purity.
EXAMPLE-3
The process as described in Example-1 above was repeated except the catalyst used was 2.0 g sulfuric acid. The product Triclopyr-butoxyethyl ester was obtained with 90.02% yield and 99.3% purity.
EXAMPLES-4 - 7
The process as described in Example-1 above was repeated except the molar ratio of triclopyr to 2-butoxyethanol was changed. The results are tabulated in the following Table.

Example No.
Molar ratio of
Triclopyr : 2-butoxyethanol Yield
4 1:1.10 93.13%
5 1:1.07 91.59%
6 1:1.05 90.02%
7 1:1.00 91.30%

CLAIMS
1. A process for preparation of triclopyr-butoxyethyi ester by reaction of triclopyr and 2-butoxyethanol in presence of p-toluenesulfonic acid as catalyst.
2. A process as claimed in claim 1, except that the catalyst used is methanesulfonic acid.
3. A process as claimed in claim 1, except that the catalyst used is sulfuric acid.
4. A process as claimed in any of the claims 1-3, wherein the molar ratio of triclopyr : 2-butoxyethanol is 1 : (1-1.2).

5. A process as claimed in any of the claims 1-4, wherein the catalyst is used in the range of 0.5 - 5.0 mole% based on the moles of Triclopyr.
6. A process as claimed in any of the claims 1-5, wherein the reaction is carried out by:
(i) refluxing the mixture of triclopyr, 2-butoxyethanol and catalyst in
solvent at 110-115°C and simultaneously removing water during the
reaction by azeotropic distillation thereof;
(ii) cooling the reaction mass to room temperature;
(iii) washing reaction mass with water and separating phases;

(iv) back-extracting the fraction of the product dissolved in washings
into a water-immiscible organic solvent;
(v) removing solvent by distillation under reduced pressure.