The present invention provides a process for preparation of trifluorornethanesulfonic acid.
Background of the Invention
The halogenated compounds, such as fluoroalkanesulfonic acids, have wide applications as super
acids mainly in pharmaceutical, agrochemical and fine chemical industries. The
trifluorornethanesulfonic acid derivatives are also used as a component of lithium batteries, thus
finds use in various electronic items.
The Russian Patent No. 2,135,463 patent provides a process for hydrolysis of
trifluoromethylsulfonyl fluoride in an aqueous-alcoholic mixture at a temperature of 80°C to
120°C, followed by release of trifluorornethanesulfonic acid in the form of azeotrope with water.
The azeotrope is treated with oleum, followed by distillation of an anhydrous
trifluoromethanesulfonic acid mixture.
The U.S Patent No. 4,927,962 provides a method to obtain trifluoromethanesulfonic acid by
interaction of trifluoromethylsulfonyl fluoride with aqueous potassium hydroxide solution.
Further, in addition, the obtained potassium salt of trifluorornethanesulfonic acid requires
purification from fluoride ion by treatment with silicon dioxide in sulhric acid, followed by acid
decomposition of selected salt with mixture of 98% H2S04 and 26% fuming H2S04.
Thus, there is still need in the art for a simple, cost effective and commercially viable method for
hydrolysis of trifluoromethylsulfonyl fluoride which avoids the prototype process, organic
solvents such as alcoholic solvents, its multistage, the presence of solid and gaseous wastes and
the exclusion of formation of salts and solid waste.
Summarv of the Invention
In an aspect, the present invention provides a process for the preparation of
trifluoromethanesulfonic acid, comprising;
a) treating trifluoromethylsulfonyl fluoride with water,
b) isolating trifluorornethanesulfonic acid from reaction mixture of step a), wherein step a)
is carried out at a temperature of about 60°C to about 110°C.
Detailed Description of the Invention
In an embodiment, the present invention provides a process for the preparation of
trifluorornethanesulfonic acid, comprising;
a) treating trifluoromethylsulfonyl fluoride with water ,
b) isolating trifluoromethanesulfonic acid from reaction mixture of step a), wherein step a)
is carried out at a temperature of about 60°C to about 1 10°C.
The trifluoromethylsulfonyl fluoride may be prepared by any method known in the art, for
example, by method known in U.S Patent No. 4,927,962.
The step a) may be carried out at a temperature of about 60°C to about 1 10°C, for example, about
75°C to about 100°C, for about 30 minutes to about 120 hours, for example for about 2 hour to
about 95 hours.
The trifluorornethanesulfonic acid may be isolated from step a) reaction mixture by layer
separation, distillation, decantation and evaporation or mixture thereof. The
trifluorornethanesulfonic acid may be further purified by any of the method known in the art.
The pressure during step a) of the reaction may be increased from about 1 bar to about 7 bar, for
example, from about 2 bar to about 6 bar.
Preferably, the preparation of trifluorornethanesulfonic acid may be carried out in a continuous
mode.
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.
Example
Preparation of Trifluoromethanesulfonic acid
Water (950 g) was taken in the re-boiler and water was circulated at the rate of 6LPH. The
circulation rate was increased to 13 LPH. The temperature of column and the re-boiler was raised
to 80°C. The trifluoromethylsulfonyl fluoride was added to the reaction vessel at a rate of 10 g/h.
In all 91 1 g of trifluoromethylsulfonyl fluoride was added over a period of 90 hours. The
trifluoromethanesulfonic acid, so obtained, was isolated from the reaction mixture.
Yield: 22%
We claim
1. A process for the preparation of trifluoromethanesulfonic acid, comprising;
a) treating trifluoromethylsulfonyl fluoride with water ,
b) isolating trifluoromethanesulfonic acid from reaction mixture of step a), wherein step
a) is carried out at a temperature of about 60°C to about 1 10°C.
2. The process of claim 1, wherein step a) is be carried out at a temperature of about 60°C to
about 1 1 O°C.
3. The process of claim 2, wherein step a) is be carried out at a temperature of about 75°C to
about 1 00°C.
4. The process of claim 1, wherein pressure during step a) is increased from about I bar to
about 7 bar.
5. The process of claim 4, wherein pressure during step a) is increased from about 2 bar to
about 6 bar.
6. The process of claim 1, wherein trifluoromethanesulfonic acid may be isolated from step
a) reaction mixture by layer separation, distillation, decantation, removal and evaporation
or mixture thereof.