DESC:
FIELD
The present disclosure relates to a process for synthesizing triclopyr butotyl, (2-butoxyethyl [(3,5,6-trichloropyridin-2-yl)oxy]acetate) (CAS no. 64700-56-7).
BACKGROUND
Triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid) is a systemic and foliar herbicide, which is effective for controlling broadleaf weeds without affecting the grasses and conifers, especially the woody plants that are found in grasslands, uncultivated land, industrial areas, plantation crops, and rice fields. Triclopyr acts as an herbicide by getting rapidly absorbed through the roots and foliage, trans-locating throughout the plant, accumulating in the meristematic tissues and inducing auxin type responses.
Triclopyr can be administered in the form of an ester such as butoxyethyl ester, triclopyr butotyl (I) (CAS number: 64700-56-7).

Conventional processes for synthesizing triclopyr butotyl have certain limitations such as complexity of the process, low yield, and low purity.
There is, therefore, felt a need to provide a process for the synthesis of triclopyr butotyl in high yield with high purity.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a simple process for synthesizing triclopyr butotyl in high yield.
Another object of the present disclosure is to provide a process for synthesizing triclopyr butotyl with high purity.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY
In one aspect, the present disclosure provides a process for synthesis of triclopyr butotyl (I). The process of the present disclosure involves the following steps.
3,5,6-Trichloropyridine-2-ol sodium (II), a first fluid medium and a phase transfer catalyst are mixed under nitrogen atmosphere to obtain a first resultant mixture.
The first resultant mixture is heated to a temperature in the range of 40 ?C to 80 ?C. 2-Butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is slowly added to the heated first resultant mixture to obtain a first reaction mixture. The first reaction mixture is stirred to obtain a first product mixture.
The first product mixture is distilled to obtain a residual mass.
The residual mass is diluted with a second fluid medium to obtain a second resultant mixture. Water soluble components are separated from the second resultant mixture with the help of water, followed by distillation to obtain crude I having purity in the range of 96 % to 98 %.
Crude I is purified by distillation under reduced pressure to obtain I having purity in the range of 99 % to 99.9 %. The yield of I is in the range of 90 % to 98%.
2-Butoxyethyl-haloacetate (III) is at least one selected from the group consisting of 2-butoxyethyl-chloroacetate, and 2-butoxyethyl-bromoacetate.
The molar ratio of II to III is in the range of 1:1 to 1:1.2.
The phase transfer catalyst is at least one selected from the group consisting of tetrabutyl ammonium bromide (TBAB), triethyl benzyl ammonium chloride (TEBACl), ethyl trimethyl ammonium chloride, ethyl trimethyl ammonium bromide, and 18-Crown-6-Ether.
The molar ratio of the phase transfer catalyst to II is in the range of 1:100 to 4:100.
The first fluid medium is selected from the group consisting of dimethyl-formamide, N-methylpyrrolidone, dimethylsulfoxide, and dimethyl acetamide.
The second fluid medium is toluene.
The step of slowly adding III to the heated first resultant mixture is carried out over a period of 0.5 hour to 3 hours.
The step of stirring the first reaction mixture is carried out for 2 hours to 12 hours.
2-Butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % used in the process of the present disclosure can be obtained by distillation of III having purity of less than 99 %.
In accordance with the embodiments of the present disclosure, 2-butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is obtained by a process comprising the following steps:
Haloacetic acid (IV) is dissolved in a third fluid medium at a temperature in the range of 25 ?C to 40 ?C to obtain a clear solution. 2-Butoxyethanol (V) and an acid are added to the clear solution to obtain a second reaction mixture.
IV is esterified by heating the second reaction mixture at a temperature in the range of 80 ?C to 140 ?C, while separating water formed during esterification, to obtain a second product mixture comprising 2-butoxyethyl-haloacetate (III).
The second product mixture is cooled to a temperature in the range of 0 ?C to 10 ?C. Water is added to the cooled second product mixture to obtain a biphasic mixture comprising an organic phase and an aqueous phase. The organic phase is separated followed by subjecting the organic phase to distillation to obtain crude III.
Crude III is purified by distillation under reduced pressure to obtain III having purity in the range of 99 % to 99.9 %.
Haloacetic acid is at least one selected from the group consisting of chloroacetic acid and bromoacetic acid.
The acid used for adding to the clear solution is at least one selected from the group consisting of sulfuric acid, hydrochloric acid, benzenesulfonic acid, benzene-di-sulfonic acid, triflic acid, and acidic ion exchange resins.
The third fluid medium is at least one selected from the group consisting of toluene, chlorobenzene, xylene, dichlorobenzene, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, dimethyl acetamide, acetonitrile, methyl isobutyl ketone, and tetrahydrofuran.
The separation of water in the step of esterification is carried out by azeotropic distillation.
The molar ratio of the acid to IV is in the range of 0.5:100 to 2:100.
The molar ratio of IV to V is in the range of 1:1 to 1:1.2.

DETAILED DESCRIPTION
Triclopyr butotyl is a systemic and foliar herbicide. Conventional processes for synthesis of triclopyr butotyl have certain limitations.
The present disclosure envisages a simple process for synthesis of triclopyr butotyl (I) (CAS no. 64700-56-7) in high yield and with high purity.

In an aspect, the present disclosure provides a process for synthesis of triclopyr butotyl involving alkylation of 3,5,6-trichloropyridine-2-ol sodium (II) with 2-butoxyethyl-haloacetate (III) in the presence of a phase transfer catalyst.
The scheme for synthesis of triclopyr butotyl, in accordance with the process of the present disclosure, is represented herein below as scheme-I:
Scheme I: Synthesis of triclopyr butotyl (I)

More specifically, the process of the present disclosure involves the following steps.
3,5,6-Trichloropyridine-2-ol sodium (II), a first fluid medium and a phase transfer catalyst are mixed under nitrogen atmosphere to obtain a first resultant mixture.
The first resultant mixture is heated to a temperature in the range of 40 ?C to 80 ?C. 2-Butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is slowly added to the heated first resultant mixture to obtain a first reaction mixture. The first reaction mixture is stirred to obtain a first product mixture.
The first product mixture is distilled to obtain a residual mass.
The residual mass is diluted with a second fluid medium to obtain a second resultant mixture. Water soluble components are separated from the second resultant mixture with the help of water, followed by distillation to obtain crude I having purity in the range of 96 % to 98 %.
Crude I is purified by distillation under reduced pressure to obtain I having purity in the range of 99 % to 99.9 %. The yield of I is in the range of 90 % to 98%.
2-Butoxyethyl-haloacetate (III) is at least one selected from the group consisting of 2-butoxyethyl-chloroacetate, and 2-butoxyethyl-bromoacetate.
The molar ratio of II to III is in the range of 1:1 to 1:1.2.
In accordance with one embodiment of the present disclosure, the molar ratio of II to III is 1:1.1.
The phase transfer catalyst is at least one selected from the group consisting of tetrabutyl ammonium bromide (TBAB), triethyl benzyl ammonium chloride (TEBACl), ethyl trimethyl ammonium chloride, ethyl trimethyl ammonium bromide, and 18-Crown-6-Ether.
In accordance with one embodiment of the present disclosure, the phase transfer catalyst is tetrabutyl ammonium bromide (TBAB).
The molar ratio of the phase transfer catalyst to II is in the range of 1:100 to 4:100.
In accordance with one embodiment of the present disclosure, the molar ratio of the phase transfer catalyst to II is 2:100.
The first fluid medium is selected from the group consisting of dimethyl-formamide, N-methylpyrrolidone, dimethylsulfoxide, and dimethyl acetamide.
In accordance with an embodiment of the present disclosure, the first fluid medium is dimethylformamide.
In accordance with another embodiment of the present disclosure, the first fluid medium is dimethylsulfoxide.
In the step of distillation of the first product mixture, the distillate comprises the first fluid medium. The weight of the recovered first fluid medium is 95 weight % to 99 weight % of the weight of the first fluid medium used in the step of alkylation. The recovered first fluid medium can be reused.
The second fluid medium is toluene.
The step of slowly adding III to the heated first resultant mixture is carried out over a period of 0.5 hour to 3 hours.
In accordance with one embodiment of the present disclosure, the slow addition of III to the heated first resultant mixture is carried out over 1 hour.
The step of stirring the first reaction mixture is carried out for 2 hours to 12 hours.
In accordance with one embodiment of the present disclosure, the first reaction mixture is stirred at 60 ?C for 7 hours to obtain the first product mixture.
2-Butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % used in the process of the present disclosure can be obtained by distillation of III having purity of less than 99 %.
In accordance with the embodiments of the present disclosure, the 2-butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is obtained by esterification of haloacetic acid (IV) by 2-butoxyethanol (V). The esterification of haloacetic acid is represented by scheme-II.
Scheme-II: Esterification of haloacetic acid (IV)

More specifically, the esterification of haloacetic acid in accordance with the process of the present disclosure involves the following steps:
Haloacetic acid (IV) is dissolved in a third fluid medium at a temperature in the range of 25 ?C to 40 ?C to obtain a clear solution. 2-Butoxyethanol (V) and an acid are added to the clear solution to obtain a second reaction mixture.
IV is esterified by heating the second reaction mixture at a temperature in the range of 80 ?C to 140 ?C, while separating water formed during esterification, to obtain a second product mixture comprising 2-butoxyethyl-haloacetate (III).
The second product mixture is cooled to a temperature in the range of 0 ?C to 10 ?C. Water is added to the cooled second product mixture to obtain a biphasic mixture comprising an organic phase and an aqueous phase. The organic phase is separated followed by subjecting the organic phase to distillation to obtain crude III.
Crude III is purified by distillation under reduced pressure to obtain III having purity in the range of 99 % to 99.9 %.
Haloacetic acid is at least one selected from the group consisting of chloroacetic acid and bromoacetic acid.
The acid used for adding to the clear solution is at least one selected from the group consisting of sulfuric acid, hydrochloric acid, benzenesulfonic acid, benzene-di-sulfonic acid, triflic acid, and acidic ion exchange resins. Acidic ion exchange resins used in the process of the present disclosure bear sulfonic acid groups.
In accordance with one embodiment of the present disclosure, the acid is sulfuric acid.
The third fluid medium is at least one selected from the group consisting of toluene, chlorobenzene, xylene, dichlorobenzene, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, dimethyl acetamide, acetonitrile, methyl isobutyl ketone, and tetrahydrofuran.
In accordance with an embodiment of the present disclosure, the third fluid medium is toluene.
In accordance with another embodiment of the present disclosure, the third fluid medium is chlorobenzene.
In accordance with yet another embodiment of the present disclosure, the third fluid medium is xylene.
The separation of water in the step of esterification is carried out by azeotropic distillation.
In accordance with one embodiment of the present disclosure, the step of esterification is carried out at 110 ?C.
The molar ratio of the acid to IV is in the range of 0.5:100 to 2:100.
In accordance with one embodiment of the present disclosure, the molar ratio of the acid to IV is 1:100.
The molar ratio of IV to V is in the range of 1:1 to 1:1.2.
In accordance with one embodiment of the present disclosure, the molar ratio of IV to V is 1:1.05.
The step of purifying the crude III involves distillation. The fraction distilling out in the temperature range of 162 ?C to 165 ?C at 0.5 mm of Hg is pure III.
The process of the present disclosure is simple, and provides I with high yield and high purity. The process involves purification by distillation. The fluid media are recovered. Therefore, the process of the present disclosure is environmentally friendly.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
Experimental details:
A) Alkylation step
Example-1
To a reactor maintained under nitrogen atmosphere, were added dimethyl formamide (DMF) (300 ml), 3,5,6-trichloropyridine-2-ol sodium (II) (220.5 g), and TBAB (5 g) (Tetra butyl ammonium bromide) to obtain a first resultant mixture.
The first resultant mixture was heated at 60 °C, and 2-butoxyethyl-chloroacetate (213 g) was slowly added to the heated first resultant mixture over 1 hour at 60 °C to obtain a first reaction mixture. The first reaction mixture was stirred at 60 °C for 7 hours to obtain a first product mixture. HPLC analysis of the first product mixture showed <0.5% II with >95% I.
DMF was distilled under reduced pressure at 70°C to obtain recovered DMF and a residual mass. Toluene (500 ml) was added to the residual mass to obtain a second resultant mixture, which was cooled to 25 ?C. The cooled second resultant mixture was washed twice with 200 ml water to separate water soluble components. The washed mass was distilled to separate toluene to obtain recovered toluene and crude I.
Weight of crude I = 360 gm/mole. HPLC analysis: I = 97%, II = <0.1%, and an impurity = 2%.
Crude I was subjected to distillation under reduced pressure using 6” hyflux column and claisen head. During distillation, the pressure was maintained at 0.5 mm Hg. The fraction that distilled at a temperature in the range of 162 to 165°C at 0.5 mm Hg was collected as I.
Weight of I = 330 g. HPLC analysis: I = 99.5%, II = 0 and Impurity = <0.1%.
Colour = Colourless, Yield of I after distillation = 92%.

Example-2
To a reactor maintained under nitrogen atmosphere, were added dimethyl formamide (DMF) (500 ml), 3,5,6-trichloropyridine-2-ol sodium (II) (220.5 g), and TBAB (5 g) (Tetra butyl ammonium bromide) to obtain a first resultant mixture.
The first resultant mixture was heated at 60 °C, and 2-butoxyethyl-bromoacetate (250 g) was slowly added to the heated first resultant mixture over 1 hour at 60 °C to obtain a first reaction mixture. The first reaction mixture was stirred at 60 °C for 7 hours to obtain a first product mixture. HPLC analysis of the first product mixture showed <0.5% II with >95% I.
DMF was distilled under reduced pressure at 70°C to obtain recovered DMF and a residual mass. Toluene (500 ml) was added to the residual mass to obtain a second resultant mixture, which was cooled to 25 ?C. The cooled second resultant mixture was washed twice with 200 ml water to separate water soluble components. The washed mass was distilled to separate toluene to obtain recovered toluene and crude I.
Weight of crude I = 365 gm/mole. HPLC analysis: I = 97%, II = <0.1%, and an impurity = 2%.
Crude I was subjected to distillation under reduced pressure using 6” hyflux column and claisen head. During distillation, the pressure was maintained at 0.5 mm Hg. The fraction that distilled at a temperature in the range of 162 to 165°C at 0.5 mm Hg was collected as I.
Weight of I = 340 g. HPLC analysis: I = 99.6%, II = 0 and Impurity = <0.1%.
Colour = Colourless, Yield of I after distillation = 95%.

Example-3
To a reactor maintained under nitrogen atmosphere, were added dimethyl sulfoxide (DMSO) (300 ml), 3,5,6-trichloropyridine-2-ol sodium (II) (220.5 g), and TBAB (5 g) (Tetra butyl ammonium bromide) to obtain a first resultant mixture.
The first resultant mixture was heated at 60 °C, and 2-butoxyethyl-chloroacetate (213 g) was slowly added to the heated first resultant mixture over 1 hour at 60 °C to obtain a first reaction mixture. The first reaction mixture was stirred at 60 °C for 7 hours to obtain a first product mixture. HPLC analysis of the first product mixture showed <0.5% II with >95% I.
DMSO was distilled under reduced pressure at 70°C to obtain recovered DMSO and a residual mass. Toluene (500 ml) was added to the residual mass to obtain a second resultant mixture, which was cooled to 25 ?C. The cooled second resultant mixture was washed twice with 200 ml water to separate water soluble components. The washed mass was distilled to separate toluene to obtain recovered toluene and crude I.
Weight of crude I = 360 g/mole. HPLC analysis: I = 97%, II = <0.1%, and an impurity = 2%.
Crude I residue was subjected to distillation under reduced pressure using 6” hyflux column and claisen head. During distillation, the pressure was maintained at 0.5 mm Hg. The fraction that distilled at a temperature in the range of 162 to 165°C at 0.5 mm Hg was collected as I.
Weight of I = 326 g. HPLC analysis: I = 99.5%, II = 0 and Impurity = <0.1%.
Colour = Colourless, Yield of I after distillation = 91%.

B) Esterification step
Example-4
Toluene (300 ml) and chloroacetic acid (94.5 g) were charged to a reactor, and the mixture was maintained at 35 ?C to dissolve chloroacetic acid and obtain a clear solution. To the clear solution were added 98% H2SO4 (1 g) and 2-butoxyethanol (123 g) to obtain a second reaction mixture.
The second reaction mixture was stirred while heating at 110 ?C, with continuous separation of water azeotropically. Heating was continued till complete removal of water. After complete removal of water, the mass was stirred for 1 hour to obtain a second product mixture.
The second product mixture was cooled to 25 ?C, and then to 10°C. Water (100 ml) was added to the cooled second product mixture and the resulting mixture was stirred at 10°C. Stirring was stopped, and the aqueous layer and organic layer were separated. The separated organic layer was washed with water (100 ml) to obtain a washed organic layer.
Toluene was separated from the washed organic layer by distillation to obtain crude III. Crude III was purified by distillation under reduced pressure to obtain 2-butoxyethyl-chloroacetate (III).
Weight = 190 g, GLC purity = 99.6%, Yield = 97%.

Example-5
Toluene (300 ml) and bromoacetic acid (139 g) were charged to a reactor, and the mixture was maintained at 35 ?C to dissolve bromoacetic acid and obtain a clear solution. To the clear solution were added 98% H2SO4 (1 g) and 2-butoxyethanol (123 g) to obtain a second reaction mixture.
The second reaction mixture was stirred while heating at 110 ?C, with continuous separation of water azeotropically. Heating was continued till complete removal of water. After complete removal of water, the mass was stirred for 1 hour to obtain a second product mixture.
The second product mixture was cooled to 25 ?C, and then to 10°C. Water (100 ml) was added to the cooled second product mixture and the resulting mixture was stirred at 10°C. Stirring was stopped, and the aqueous layer and organic layer were separated. The separated organic layer was washed with water (100 ml) to obtain a washed organic layer.
Toluene was separated from the washed organic layer by distillation to obtain crude III. Crude III was purified by distillation under reduced pressure (10 mm of Hg) to obtain 2-butoxyethyl-bromoacetate (III).
Weight = 230 g. GLC purity = 99.8% Yield = 96%.

Example-6
Chlorobenzene (300 ml) and chloroacetic acid (94.5 g) were charged to a reactor, and the mixture was maintained at 35 ?C to dissolve chloroacetic acid and obtain a clear solution. To the clear solution were added 98% H2SO4 (1 g) and 2-butoxyethanol (123 g) to obtain a second reaction mixture.
The second reaction mixture was stirred while heating at 110 ?C, with continuous separation of water azeotropically. Heating was continued till complete removal of water. After complete removal of water, the mass was stirred for 1 hour to obtain a second product mixture.
The second product mixture was cooled to 25 ?C, and then to 10°C. Water (100 ml) was added to the cooled second product mixture and the resulting mixture was stirred at 10°C. Stirring was stopped, and the aqueous layer and organic layer were separated. The separated organic layer was washed with water (100 ml) to obtain a washed organic layer.
Chlorobenzene was separated from the washed organic layer by distillation to obtain crude III. Crude III was purified by distillation under reduced pressure to obtain 2-butoxyethyl-chloroacetate (III).
Weight = 186 g. GLC purity = 99.7% Yield = 95.34%.

Example-7
Xylene (400 ml) and chloroacetic acid (94.5 g) were charged to a reactor, and the mixture was maintained at 35 ?C to dissolve chloroacetic acid and obtain a clear solution. To the clear solution were added 98% H2SO4 (1 g) and 2-butoxyethanol (123 g) to obtain a second reaction mixture.
The second reaction mixture was stirred while heating at 110 ?C, with continuous separation of water azeotropically. Heating was continued till complete removal of water. After complete removal of water, the mass was stirred for 1 hour to obtain a second product mixture.
The second product mixture was cooled to 25 ?C, and then to 10°C. Water (100 ml) was added to the cooled second product mixture and the resulting mixture was stirred at 10°C. Stirring was stopped, and the aqueous layer and organic layer were separated. The separated organic layer was washed with water (100 ml) to obtain a washed organic layer.
Xylene was separated from the washed organic layer by distillation to obtain crude III. Crude III was purified by distillation under reduced pressure to obtain 2-butoxyethyl-chloroacetate (III).
Weight = 190 g. GLC purity = 99.7% Yield = 97.4%.
Example-8
Xylene (400 ml) and bromoacetic acid (139 g) were charged to a reactor, and the mixture was maintained at 35 ?C to dissolve bromoacetic acid and obtain a clear solution. To the clear solution were added 98% H2SO4 (1 g) and 2-butoxyethanol (123 g) to obtain a second reaction mixture.
The second reaction mixture was stirred while heating at 110 ?C, with continuous separation of water azeotropically. Heating was continued till complete removal of water. After complete removal of water, the mass was stirred for 1 hour to obtain a second product mixture.
The second product mixture was cooled to 25 ?C, and then to 10°C. Water (100 ml) was added to the cooled second product mixture and the resulting mixture was stirred at 10°C. Stirring was stopped, and the aqueous layer and organic layer were separated. The separated organic layer was washed with water (100 ml) to obtain a washed organic layer.
Xylene was separated from the washed organic layer by distillation to obtain crude III. Crude III was purified by distillation under reduced pressure to obtain 2-butoxyethyl-bromoacetate (III).
Weight = 229 g. GLC purity = 99.6% Yield = 95.4%.

TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a simple process for preparing the triclopyr butotyl (I):
? with high purity; and
? in high yield.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A process for synthesis of triclopyr butotyl (I), the process comprising the following steps:
a) mixing 3,5,6-trichloropyridine-2-ol sodium (II), a first fluid medium and a phase transfer catalyst, under nitrogen atmosphere, to obtain a first resultant mixture;
b) heating the first resultant mixture to a temperature in the range of 40 ?C to 80 ?C, and slowly adding 2-butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % to the heated first resultant mixture to obtain a first reaction mixture, followed by stirring the first reaction mixture to obtain a first product mixture;
c) distilling the first product mixture to obtain a residual mass; and
d) diluting the residual mass with a second fluid medium to obtain a second resultant mixture, and separating water soluble components from the second resultant mixture with the help of water, followed by distillation to obtain crude I having purity in the range of 96 % to 98 %; and
e) purifying the crude I by distillation under reduced pressure to obtain I having purity in the range of 99 % to 99.9 %.
wherein the yield of I is in the range of 90 % to 98%.
2. The process as claimed in claim 1, wherein the 2-butoxyethyl-haloacetate (III) is at least one selected from the group consisting of 2-butoxyethyl-chloroacetate, and 2-butoxyethyl-bromoacetate.
3. The process as claimed in claim 1, wherein the molar ratio of II to III is in the range of 1:1 to 1:1.2.
4. The process as claimed in claim 1, wherein the phase transfer catalyst is at least one selected from the group consisting of tetrabutyl ammonium bromide (TBAB), triethyl benzyl ammonium chloride (TEBACl), ethyl trimethyl ammonium chloride, ethyl trimethyl ammonium bromide, and 18-Crown-6-Ether.
5. The process as claimed in claim 1 or 4, wherein the molar ratio of the phase transfer catalyst to II is in the range of 1:100 to 4:100.
6. The process as claimed in claim 1, wherein the first fluid medium is at least one selected from the group consisting of dimethyl-formamide, N-methylpyrrolidone, dimethylsulfoxide, and dimethyl acetamide.
7. The process as claimed in claim 1, wherein the second fluid medium is toluene.
8. The process as claimed in claim 1, wherein the step of slowly adding III to the heated first resultant mixture is carried out over a period of 0.5 hour to 3 hours; and the step of stirring the first reaction mixture at a temperature in the range of 40 ?C to 80 ?C is carried out for 2 hours to 12 hours.
9. The process as claimed in claim 1, wherein 2-butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is obtained by distillation of III having purity of less than 99 %.
10. The process as claimed in claim 1, wherein 2-butoxyethyl-haloacetate (III) having purity in the range of 99 % to 99.9 % is obtained by a process comprising the following steps:
i. dissolving haloacetic acid (IV) in a third fluid medium at a temperature in the range of 25 ?C to 40 ?C to obtain a clear solution, followed by adding 2-butoxyethanol (V) and an acid to the clear solution to obtain a second reaction mixture;
ii. esterifying IV by heating the second reaction mixture at a temperature in the range of 80 ?C to 140 ?C, while separating water formed during esterification, to obtain a second product mixture comprising 2-butoxyethyl-haloacetate (III);
iii. cooling the second product mixture to a temperature in the range of 0 ?C to 10 ?C, and adding water to the cooled second product mixture to obtain a biphasic mixture comprising an organic phase and an aqueous phase, separating the organic phase, followed by subjecting the organic phase to distillation to obtain crude III;
iv. purifying crude III by distillation under reduced pressure to obtain III having purity in the range of 99 % to 99.9 %.
11. The process as claimed in claim 10, wherein the haloacetic acid is at least one selected from the group consisting of chloroacetic acid and bromoacetic acid.
12. The process as claimed in claim 10, wherein the acid used for adding to the clear solution is at least one selected from the group consisting of sulfuric acid, hydrochloric acid, benzenesulfonic acid, benzene-di-sulfonic acid, triflic acid, and acidic ion exchange resins.
13. The process as claimed in claim 10, wherein the third fluid medium is at least one selected from the group consisting of toluene, chlorobenzene, xylene, dichlorobenzene, dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide, dimethyl acetamide, acetonitrile, methyl isobutyl ketone, and tetrahydrofuran.
14. The process as claimed in claim 10, wherein the separation of water in step (ii) is carried out by azeotropic distillation.
15. The process as claimed in claim 10, wherein the molar ratio of the acid to IV is in the range of 0.5:100 to 2:100.
16. The process as claimed in claim 10, wherein the molar ratio of IV to V is in the range of 1:1 to 1:1.2.