FIELD OF INVENTION:
The present invention relates to process for preparation of 2,2,2-trifluoroethyl chloride with ammonia to produce 2,2,2-trifluoroethylamine.
BACKGROUND OF INVENTION:
Of the methods available for the commercial production of 2,2,2-trifluoroethylamine, the ammonolysis of the corresponding halides is the most convenient and economical.
U.S. Pat. No - 2,348,321 discloses the reaction of 2,2,2-trifluoroethyl chloride with a four-fold excess of aqueous ammonia in a steel bomb at 185°C. for 6 hours. No yield or conversion is given. In the method of 2348321, no organic solvent is employed, and concentrated aqueous ammonia is used as a reaction solvent. CF3CH2X is hardly soluble in concentrated aqueous ammonia, whereby the reactivity with NH3 tends to be low, and a problem that the yield tends to be low. Further, when the method 2348321 was practically employed, it was necessary to use an expensive reactor made of a corrosion resistant material such as hastelloy, since there was a problem of corrosion of the reactor.
Dikey et al (Ind, Eng. Chem., Vol 48, P -209 1956 ) report the same reaction using a six-fold excess of ammonia. In this case, the conversion is 100% and the isolated yield of the amine is 59%. Similarly, the bromide gave 55% yield of the amine. According to Meen and Wright(J. Org. Chem., Vol. - 19, P-391, 1954 ) the reaction of 2,2,2-trifluoroethyl bromide with anhydrous ammonia in the absence of a solvent at 130°C - 140°C gave 80% of the amine, isolated as the hydrochloride salt and contaminated with 5% of ammonium chloride. The above methods have limitations when applied to large scale industrial preparations. The use of ammonia at elevated temperatures causes high pressure necessitating the use of a specialty constructed pressure vessel. While the employment of aqueous ammonia help to reduce the pressure somewhat over the anhydrous method, the presence of water leads to corrosion of the vessel unless expensive, high alloy reactors are used.
It is accordingly an object of the present invention to provide a process for producing 2,2,2-

trifluoroethylamine in high yield, with minimal corrosion, and without the need for costly high pressure equipment.
It has been found that the use of non-aqueous solvents considerably reduces the corrosion of a stainless steel vessel relative to water. Such solvents also reduce the amount of fluoride ion generated during the reaction. Since fluoride ion cannot be added indiscriminately to waste water, its removal adds to the expense of such a process. Accordingly, the reduced production of fluoride ion in accordance with the present invention represents a further advantage.
SUMMARY OF THE INVENTION
Present invention discloses a process in which ammonolysis of 2,2,2-trifluoroethyl chloride (R-133a), is performed in presence of tetrabutyl ammonium bromide (TBAB). The process has improved yield and conversion as compared to process of prior art.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention relates to a process for preparation of 2,2,2-trifluoroethyl amine by reaction of Trifluoroethylchloride with ammonia in presence of tetra butyl ammonium bromide and a solvent.
These and other objects and advantages have been realized in accordance with the present invention pursuant to which a 2,2,2-trifluoroethyl halide is reacted with from 1 to 3 times its molar amount of ammonia at a temperature of about 170°C to 240°C in the presence of a substantially anhydrous inert solvent present in at least about the same molar amount as the trifluoroethyl halide.
The process comprises reacting trifluoroethylchloride with anhydrous ammonia in presence of TBAB and a solvent at a temperature ranging from 170 to 240 degree C, preferably 190 degree C for a specified duration so as to allow the pressure to drop to 30 to 45 9c of the initial pressure of the reactor.
In an embodiment the reaction temperature is maintained for 10 to 12 hrs, preferably 11 hrs.
The molar ratio of trifluoroethylchloride to that of anhydrous ammonia is 1:1 to 1:3.
The 9c of TBAB in solution is in the range of 1-5 9c with respect to solvent, and the 9c of solvent in the reaction mixture ranges from 50 to 609c.

After the reaction is complete trifluoroethyl amine can be obtained by condensation followed by arrangements to remove the undesired products. The undesired product may comprise of the unreacted reactants and side products like secondary amines formed during the reaction.
In an embodiment the reaction mixture is cooled to a temperature ranging from 100 to 150 degree C, preferably 120 degree C. The cooled reaction mixture is then condensed with the help of a condensor followed by a HCl trap to scrub the excess ammonia. The crude product distilled in flask contains the reactant R133a, TFEA, sec. amine and some solvent. The final product is obtained by distillation.
In an another embodiment suitable solvents for the practice of the invention are those which under the reactions conditions are liquid and inert. Representative solvents include sulfolane but are preferably N-methylpyrrolidone and glycols and ethers thereof such as 2-(2-ethoxyethoxy)-ethanol, triethyleneglycol, dimethylether and the like.
Example:
A 2-litre stainless-steel autoclave was evacuated and charged with 479 g of N-Methyl Pyrrolidone, 7.1 g of tetra butyl ammonium bromide (TBAB) followed by the addition of 230 g of 2,2,2-Trifluoroethylchloride (R133a) and 107 g of Anhydrous ammonia. The mixture was stirred and heated to 190°C for 11 hrs during which pressure dropped from 63.5 kg/cm2 to 41 kg/cm2. The mixture was allowed to cool to 120°C and the material was drained out into a 2-necked round bottom flask fitted with condensor (cooled at -20 °C) followed by a HCl trap to scrub the excess ammonia. The crude product distilled in round bottom flask contains the reactant R133a, TFEA, sec. amine and some solvent. The filtered the ammonium chloride formed from the residue which was analyzed for CI" and F" and the filtrate was then distilled to recover the NMP.

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RESULTS:
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We Claim:
1. A process for preparation of 2,2,2-trifluoroethyl amine by reaction of Trifluoroethylchloride with N-methyl pyrrolidone in presence of tetra butyl ammonium bromide and in presence of a suitable solvent.
2. The process as claimed in claim 1, wherein the temperature of the reaction is in the range of 170 to 240 degree C preferably 190 degree C.
3. The process as claimed in claim 1, wherein the reaction is performed for a duration so as to allow the pressure to drop to 30 to 45 % of the initial pressure of the reactor.
4. The process as claimed in claim 3, wherein the temperature of the reaction is maintained for 10 to 12 hrs, preferably 11 hrs.
5. The process as claimed in claim 1, wherein the molar ratio of trifluoroethylchloride to that of anhydrous ammonia is 1:1 to 1:3.
6. The process as claimed in claim 1, wherein the % of TBAB in solution is in the range of 1-5%.
7. The process as claimed in claim 1, wherein the % of solvent in the reaction mixture ranges from 50 to 60%.
8. The process as claimed in claim 1, wherein the solvent is selected from a group consisting of sulfolane, N-methylpyrrolidone, 2-(2-ethoxyethoxy)-ethanol, triethyleneglycol dimethylether and the like.
9. The process as claimed in claim 1, wherein after the reaction, trifluoroethyl amine is isolated by cooling reaction mixture at a temperature ranging from 100 to 150 degree C, followed by condensation and passing the gas through a HC1 trap, followed by distillation.
10. A process for preparation of 2,2,2-trifluoroethyl amine substantially such as herein described with reference to foregoing examples.