Field of the invention
The present invention provides a process for the preparation of a compound of Formula I.
Background of the invention
The compound of Formula I is widely used in industry, as an intermediate for chemical synthesis of agrochemicals and pharmaceuticals.
X is selected from fluorine, chlorine, bromine, iodine
n is selected from 1 to 6
Formula I
Particularly, 2,2,2-trifluoroethyl trifluoroacetate finds application as a co-solvent in lithium batteries, semi-conductor cleaning, foam blowing application and also as a general fluorinated organic solvent.
The U.S. Patent No. 5,405,991 provides a process for producing carboxylic acid esters by reacting carboxylic acid chlorides or carboxylic acid bromides or carboxylic acid anhydride with alcohols. The process is carried out in an anhydrous medium and in the presence of catalyst selected from alkali metal salts or ‘onium’ salts of the carboxylic acid. The ‘onium’ salt is selected from pyridinium salt or piperidinium salt. The purpose of using pyridinium salt or piperidinium salt is to capture the liberated hydrogen chloride or hydrogen bromide formed in the reaction. However, the use of pyridine in industrial process is not preferred and hence the process is industrially unfavourable.
The present invention provides a process for the preparation of a compound of Formula I which is simple, easy to perform and industrially doable.

Summary of the invention
The present invention provides a process for the preparation of a compound of Formula I comprising;
a) reacting compound of Formula II with compound of Formula III in the presence or absence of alkali metal fluoride to obtain a compound of Formula I,
Formula I
wherein X is selected from fluorine, chlorine, bromine, iodine
and n is selected from 1 to 6
Formula II
Formula III
b) isolating a compound of Formula I from step a).
Detailed description of the invention
In an aspect, the present invention provides a process for the preparation of a compound of Formula I comprising;
a) reacting compound of Formula II with compound of Formula III in the presence or absence of alkali metal fluoride to obtain a compound of Formula I,
Formula I
wherein, X is selected from fluorine, chlorine, bromine, iodine
and n is selected from 1 to 6
Formula II
Formula III
b) isolating a compound of Formula I from step a).
The compound of Formula II may be prepared by any method known in the art, for example, known in the Indian Patent No. 257468.
The step a) is carried out at a temperature of about -78oC to 100oC, for about 10 minutes to 12 hours.
The process of the present invention may or may not be carried out in the presence of alkali metal fluoride. The alkali metal fluoride is in anhydrous form. The alkali metal fluoride is selected from sodium fluoride, potassium fluoride and cesium fluoride.
The compound of Formula I is isolated by any of the methods in the art, for example, decantation, distillation, evaporation and layer separation or mixture thereof.

The compound of Formula I, as obtained by the present invention, has purity of about greater than 98%, preferably greater than 98.5%.

In another aspect, the 2,2,2-trifluoroethyl trifluoroacetate prepared by the process of the present invention has a purity greater than 98.5%.

In yet another aspect, the 2,2,2-trifluoroethyl trifluoroacetate prepared by the process of the present invention has a purity greater than 99%.

The term ‘about’ refers to a variation of 10% on the higher and lower side of specified parameter.

While the present invention has been described in terms of its specific embodiments, certain modifications and equivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention.

The following examples are given by way of illustration and therefore should not be construed to limit the scope of the present invention.

Examples
Example 1: Preparation of 2,2,2-Trifluoroethyl Trifluoroacetate

The 2,2,2-trifluoroethanol (100g, 1 mole) and anhydrous potassium fluoride (65g, 1.1 mole) were taken together in a 450ml stainless steel autoclave. The autoclave was then cooled to
-78°C. Subsequently, trifluoroacetylfluoride (128g, 1.1mole) was added to the autoclave. After completion of addition, the reaction mass was maintained at a temperature in the range of 25 to 30°C. The reaction mass was stirred for 10 minutes. Thereafter, the reaction mass was heated to 100°C with continuous stirring for a period of three hours. After completion of reaction, the reaction temperature was maintained at 25°C. The reaction mass was subjected to distillation, title product was collected at the vapour temperature of 55°C.
Yield (%): 76
Purity: 98.46% by GC

We claim:
1.A process for the preparation of a compound of Formula I comprising;
a)reacting compound of Formula II with compound of Formula III in the presence or absence of alkali metal fluoride to obtain a compound of Formula I,

Formula I

wherein X is selected from fluorine, chlorine, bromine, iodine
and n is selected from 1 to 6

Formula II
Formula III

b)isolating a compound of Formula I from step a) reaction mixture.

2. The process as claimed in claim 1, wherein step a) is carried out at a temperature in range of -78oC to 100oC.
3. The process as claimed in claim 1, wherein step a) is carried out in the presence of alkali metal fluoride.
4. The process as claimed in claim 3, wherein the alkali metal fluoride is selected from sodium fluoride, potassium fluoride and cesium fluoride.
5. The 2,2,2-trifluoroethyl trifluoroacetate, prepared by the process claimed in claim 1, has a purity greater than 98.5%.
6. The process as claimed in claim 1, wherein step b) is carried out by decantation, distillation, evaporation and layer separation or mixture thereof.