Field of the Invention
The present invention relates to the process for the preparation of 2,2,2-trifluoroethyl 2-
methylprop-2-enoate of Formula I.
O O
F
F
CF3CH2OH
dimethylamino pyridine
O
O
F
F
F
2,2,2-trifluoroethyl methacrylate
Formula I
Background of the Invention
The fluoroalkyl methacrylates are important intermediates for organic synthesis. The
applications of the fluoroalkyl methacrylates are especially in anti-dust or anti-soiling paints for various
supports such as exterior coatings and metal furniture, optical fibers, contact lenses, lithography,
electrophotography, heat-resistant materials, dental resins and so on. Particularly, 2,2,2-trifluoroethyl
2-methylprop-2-enoate of Formula I, is widely applied in many ways. It is used in painting for
improving weather-resistance, water- resistance and stain-resistance. It is also used in optical fibre's
cladding, fibre core material, haptic lens, high oxygen permeable contact lenses, and so on.
Several synthetic routes to the preparation of compound of 2,2,2-trifluoroethyl 2-methylprop-2-
enoate of Formula I are well known at present.
O O
F
F
F
CF3CH2OH
dimethylamino pyridine
O
O
F
F
F
2,2,2-trifluoroethyl methacrylate
Formula I
3
Chinese Patent No.1907945 discloses a process for the preparation of trifluoroethyl methacrylate. The process comprises reacting trifluoroethanol and methacryloyl chloride at 30℃ to 80℃ for 7h to 15h in the presence of polymerization inhibitor, followed by separating the resulting product trifluoroethyl methacrylate.
U.S. Patent No.5804687 discloses a process of preparation of halo esters of carboxylic or dicarboxylic acids.
Chinese Patent No. 101781209 provides a process for the preparation of methacrylic acid multi-fluorinated alkane ester. The process comprises reacting methacrylic acid and trifluoroacetic anhydride to obtain methacrylic acid-trifluoroacetic mixed anhydride followed by treating with multi-fluorinated alkane ester to obtain the methacrylic acid multi-fluorinated alkane ester.
The above methods use harsh reaction conditions or the yield is low or there is difficultly in preparing the raw materials and therefore are not suitable for industrial production.
The process of the present invention is simple, uses mild reaction conditions, economical and hence is suitable for industrial production.
Summary of the Invention
An aspect of the present invention provides a process for the preparation of 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I, comprising;
a) reacting alkali metal salt of methacrylic acid of Formula II with 2,2,2-trifluoroacetyl halide in the presence of an aprotic solvent to obtain a reaction mixture; and
b) reacting the reaction mixture of step a) with alkali metal salt of 2,2,2-trifluoro ethanol and a catalyst to obtain 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I.
c) isolating 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I from step b).
4
CF3CH2OH
dimethylamino pyridine
O
O
F
F
F
2,2,2-trifluoroethyl methacrylate
Formula I
O
-
O
CH3
H2C
A
+
Formula II
Detailed Description of the Invention
The present invention provides a process for the preparation of 2,2,2-trifluoroethyl 2-
methylprop-2-enoate of Formula I, comprising;
a) reacting alkali metal salt of methacrylic acid of Formula II with 2,2,2-trifluoroacetyl halide
in the presence of an aprotic solvent to obtain a reaction mixture;
b) reacting the reaction mixture of step a) with alkali metal salt of 2,2,2-trifluoro ethanol and a
catalyst to obtain 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I,
c) isolating 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I from step b).
O O
F
F
F
CF3CH2OH
dimethylamino pyridine
O
O
F
F
F
2,2,2-trifluoroethyl methacrylate
Formula I
5
O
-
O
CH3
H2C
A
+
Formula II
In an embodiment, the process of the present invention is carried out in the presence of a
stabilizing agent. The stabilizing agent is selected from the group comprising hydroquinone, 4-methoxy
hydroquinone, Copper Sulfate, Ascorbic acid, phenothiazine, and methylene blue.
As salts of methacrylic acid (Formula II), an alkali metal salt such as, for example, that of
sodium, potassium, rubidium or cesium.
The halide group of 2,2,2-trifluoroacetyl halide is selected from fluoride, chloride, bromide and
iodide.
In another embodiment, the aprotic solvent is selected from the group comprising sulpholane,
N-methyl pyrollidone, gamma butyro lactone, propylene carbonate and glyme.
As salts of 2,2,2-trifluoro ethanol, an alkali metal salt such as, for example, that of sodium,
potassium, rubidium or cesium.
The reaction may optionally take place in the presence of catalyst. The catalyst may be any
catalyst that is used in prior art for such reaction(s).
The process of the present invention is carried out at a temperature in the range of about 250C to
about 700C, preferably at a temperature in the range of about 350C to about 500C.
The process of the present invention is carried out at an atmospheric pressure.
In a yet another embodiment, an intermediate of Formula III is formed and is isolated from the
6
reaction mixture. The reaction mixture is formed upon treatment of alkali metal salt of methacrylic
acid of Formula II with 2,2,2-trifluoroacetyl halide in the presence of an aprotic solvent. The
intermediate of Formula III may be optionally isolated or carried further to step b) without isolation.
O
O O
CH3
F
F
F
H2C
Formula III
In one another embodiment, the process of the present invention is carried out as a one pot
synthesis.
The trifluoroacetyl halide is prepared by the process already known in the art. Preferably,
trifluoroacetyl fluoride is prepared by a process disclosed in the Indian Patent No. 257468.
Alkali metal salt of methacrylic acid may be prepared by the process disclosed in the present
application.
The isolation of the compound of Formula I from step b) is carried out by crystallization, recrystallization,
distillation, evaporation and decantation or mixture thereof.
The purity of compound of Formula I obtained by the process of present invention is greater
than about 95% preferably greater than about 97%.
The term ‘about’ refers to a variation of 10% on the higher and lower side of specified
parameter.
Although the subject matter has been described in considerable detail with reference to certain
preferred embodiments thereof, other embodiments are possible. As such, the spirit and scope of the
subject matter should not be limited to the description of the preferred embodiment contained therein.
7
Examples
Example 1: Preparation of 2,2,2-trifluoroethyl 2-methylprop-2-enoate
100 g of Potassium methacrylate was charged into a RBF containing 450ml sulfolane and 2g of Phenothiazine. The mass was heated to 50°C and 188g of Trifluoroacetyl fluoride was passed into the reaction mass at the same temperature for 2 hours. The mass was maintained for 2 hours at 50°C and distilled under vacuum at 75°C to give 88 g of product of Formula III with a purity of 98%.
The product of formula III was then charged into a RBF containing 66g of potassium salt of Trifluoroethanol and 150ml sulfolane at 50°C for 1 hour. The reaction was continued for a further 2 hours and the mass was distilled under vacuum at 75°C to give 54 g of the pure product with a yield of 40%.
Example 2: Preparation of 2,2,2-trifluoroethyl 2-methylprop-2-enoate
100 g of Potassium methacrylate was charged into a RBF containing 450ml sulfolane and 2g of Hydroquinone. The mass was heated to 50°C and 188g of Trifluoroacetyl fluoride was passed into the reaction mass at the same temperature for 2 hours. The mass was maintained for 2 hours at 50°C and then 138 g of potassium salt of Trifluoroethanol was added at 50°C for 1 hour. The reaction was continued for a further 2 hours and the mass was distilled under vacuum at 75°C to give 56 g of the pure product with a yield of 41%.
Example 3: Preparation of potassium salt of methacrylate
Potassium methacrylate is prepared by the reaction of Methacrylic acid with KOH and Methanol at an operating temperature of 15°C and atmospheric pressure. 790 g of Methanol and 193g of KOH are charged in the RBF and stirring started. 265g of Methacrylic acid is then added along with 356g of methanol into the reaction mass drop wise at 15°C. The reaction was continued for a further 2 hours at the same temperature. The reaction mass was then distilled under vacuum at 50°C to obtain 276g of the pure product with a yield of 95 %.

We claim:
1. A process for the preparation of 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I,
comprising;
a) reacting alkali metal salt of methacrylic acid of Formula II with 2,2,2-trifluoroacetyl halide
in the presence of an aprotic solvent to obtain a reaction mixture,
b) reacting the reaction mixture of step a) with alkali metal salt of 2,2,2-trifluoro ethanol and a
catalyst to obtain 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I, and
c) isolating 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I from step b).
O O
F
F
F
CF3CH2OH
dimethylamino pyridine
O
O
F
F
F
2,2,2-trifluoroethyl methacrylate
Formula I
O
-
O
CH3
H2C
A
+
Formula II
2. The process of claim 1, wherein the aprotic solvent is selected from the group comprising
sulpholane, N-methyl pyrollidone, gamma butyro lactone, propylene carbonate and glyme.
3. The process of claim 1, wherein alkali metal salt of 2,2,2-trifluoro ethanol is selected from
sodium, potassium, rubidium or cesium.
4. The process of claim 1, wherein is carried out at a temperature in the range of 25oC to 70oC.
5. The process of claim 1, wherein the compound of Formula I from step b) is isolated by
crystallization, re-crystallization, distillation, evaporation and decantation or mixture thereof.
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6. The purity of 2,2,2-trifluoroethyl 2-methylprop-2-enoate of Formula I, obtained by the process of claim 1, is greater than 97%.