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 2-butoxyethyl ester of chloroacetic acid.
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 2-butoxyethyl ester of chloroacetic acid
FIELD OF INVENTION
The present invention relates to preparation of 2-butoxyethyl ester of chloroacetic acid. More particularly, the present invention relates to a process for preparation of 2-butoxyethyl ester of chloroacetic acid by reaction of chloroacetic acid and 2-butoxyethanol in presence of a catalyst.
BACKGROUND AND PRIOR ART
2-Butoxyethyl chloroacetate is an intermediate for preparation of a herbicide Triclopyr.
A process for preparation of butoxyethyl ester of chloroacetic acid, has been disclosed in US2452350. This method involves catalytic esterification using mineral acid as a catalyst. However, impurities are formed in this process.
The inventors of present invention have developed a process for preparation of abovementioned intermediate (butoxyethyl ester of chloroacetic acid) with improved purity.
OBJECTS OF INVENTION
The object of present invention is to provide an efficient process for preparation of 2-butoxyethyl chloroacetate from chloroacetic acid and 2-butoxyethanol with improved purity.

DETAILED DESCRIPTION OF INVENTION
2-butoxyethyl chloroacetate is obtained by refluxing the mixture of 2-butoxyethanol, chloroacetic acid, catalyst such as p-toluene sulfonic acid or methane sulfonic acid, and solvent at 110-115°C, simultaneously removing water by azeotropic distillation followed by cooling the reaction mass to room temperature, washing it with water followed by mild alkali and again with water. The organic phase is optionally dried over a water absorbent/adsorbent and decolorized. The solvent is removed by distillation preferably under reduced pressure.
EXAMPLE-1
In a round bottom flask equipped with a mechanical stirrer, thermometer pocket, dean & stark and reflux condenser arrangement, 2.12 moles of chloroacetic acid in 190 ml toluene was taken. 2.12 moles of 2-butoxyethanol was added. 4 g. of p-toluenesulfonic acid catalyst was added. The mixture was refluxed in an oil bath for 6 hrs. Water during the reaction was removed by dean & stark arrangement. After 6 hrs. the reaction mass was analyzed and it showed 98.5% conversion. The reaction mass was cooled to room temperature and was washed with 150 ml water followed by 200 ml 10% sodium carbonate solution. Finally it was washed with 150 ml water. The organic layer was dried over anhydrous sodium sulfate and decolorized with silica gel. The solvent was removed by vacuum distillation to obtain 2-butoxyethylchloroacetate in 86.24% yield and 98.5% purity.

EXAMPLE-2
The process as described in Example 1 above was repeated except that the catalyst used was 4.0 g methanesulfonic acid, to obtain 2-butoxyethylchloroacetate in 85.39% yield and 98.2% purity.
EXAMPLES-3 & 4
The process as described in Example 1 above was repeated except the molar ratio of chloroacetic acid to 2-butoxyethanol was changed. The results are tabulated in following Table:

Example No. Molar ratio Triclopyr : 2-butoxyethanol Yield
1 1:1 86.24%
2 1:1.05 88.18%
3 1:1.10 90.12%
EXAMPLE-4
The process as described in Example 1 above was repeated except 95 ml of toluene was used instead of 190 ml. The yield of product obtained was 84.54%.
EXAMPLE-5

The process as described in Example 2 above was repeated except that 95 ml of toluene was used instead of 190 ml. The yield of product obtained was 87.09%.
EXAMPLE-6
In a round bottom flask equipped with a mechanical stirrer, thermometer pocket and reflux condenser arrangement with vacuum facility was taken 1.0582 moles of chloroacetic acid and 1.0582 moles of 2-butoxyethanol. 2.0 g. of p-toluenesulfonic acid catalyst was added. The mixture was heated in a water bath at 65-70°C under 600-630 mm Hg. During the reaction water was removed through the condenser. After 3 hrs of heating, the conversion was found to be 96.5%. The reaction mass was cooled to room temperature and was washed with 200 ml water. The organic layer was dried over anhydrous sodium sulfate. The product obtained was off-white in color in 80.16% yield and 98.02% purity.
EXAMPLE-7
The process as described in Example-6 above was repeated except that the molar ratio of chloroacetic acid to 2-butoxyethanol was changed to 1:1.05. The yield of the product obtained was 83.56%.
EXAMPLE-8 (comparative example using sulfuric acid as catalyst)
In a round bottom flask equipped with mechanical stirrer and thermometer pocket, 2.116 moles of chloroacetic acid and 2.116

moles of 2-butoxyethanol were taken. 7.0 g 98% sulfuric acid was added as a catalyst as well as water acceptor. The mixture was heated to 90-105°C in an oil bath for 4 hrs. Conversion was found to be 60%. The reaction mass was cooled and washed with 150 ml water followed by 200 ml of 10% sodium carbonate and finally with 150 ml water. The organic layer was dried over anhydrous sodium sulfate and decolorized with silica gel to obtain 2-butoxyethyl chloroacetate in 61.70% yield and 97% purity.
EXAMPLE-9
In a round bottom flask equipped with mechanical stirrer and thermometer pocket, 2.116 moles of chloroacetic acid and 2.116 moles of 2-butoxyethanol were taken. Molecular sieve was used as water absorber. 4.0 g of p-toluenesulfonic acid catalyst was added. The reaction mixture was heated to 80-110°C in an oil bath for 5 hrs. Conversion was found to be 65%. The organic product was cooled to room temperature and was given washing with 150 ml water followed by 200 ml of 10% sodium carbonate solution and finally with 150 ml water. The product was dried over anhydrous sodium sulfate and decolorized with charcoal treatment to obtain the product with 55.87% yield and 96% purity.
EXAMPLE-10
The process as described in Example 9 above was repeated except that sodium sulfate was used as water absorber instead of molecular sieve. The product was obtained with 51.01% yield and 95% purity.

EXAMPLE-11
The process as described in Example 1 was repeated except that 465 ml toluene was used instead of 190 ml. The yield of the product was found to be 90.12%.
EXAMPLE-12
The process as described in Example 2 was repeated except that 465 ml toluene was used instead of 190 ml. The yield of the product was found to be 92.31%.
EXAMPLE-13
The process as described in Example 3 was repeated except that 465 ml toluene was used instead of 190 ml. The yield of the product was found to be 94.5%.

CLAIMS:
1. A process for preparation of 2-butoxyethyl chloroacetate by
reaction of chloroacetic acid and 2-butoxyethanol in presence of p-
toluene sulfonic 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 any of the claims 1 or 2, wherein the molar ratio of chloroacetic acid to 2-butoxyethanol taken is 1 : (1-1.5).

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 chloroacetic acid.
5. A process as claimed in any of the claims 1-4, wherein 2-butoxyethyl chloroacetate is obtained by:
(i) refluxing the mixture of 2-butoxyethanol, chloroacetic acid,
catalyst and solvent at 110-115°C and simultaneously removing
water by azeotropic distillation;
(ii) cooling the reaction mass to room temperature;
(iii) washing the reaction mass with water followed by mild alkali and
again with water;
(iv) optionally drying the organic phase over a water
absorbent/adsorbent and decolorizing;
(v) removing the solvent by distillation under reduced pressure.

6. A process as claimed in any of the claims 1-4, wherein 2-
butoxyethyl chloroacetate is obtained by:
(i) heating the mixture of 2-butoxyethanol, chloroacetic acid and
catalyst at 60-75°C under 600-630 mm Hg and simultaneously
removing water;
(ii) cooling the reaction mass to room temperature;
(iii) washing the reaction mass with water followed by mild alkali and
again with water;
(iv) optionally drying the organic phase over a water
absorbent/adsorbent and decolorizing.