FIELD OF INVENTION
The present invention relates to a process for preparation of 1,1,1,5;5,5-hexafluoroacetyl
acetone.
BACKGROUND OF THE INVENTION
The 1,1,1,5,5,5-hexafluoroacetyl acetone has significant role for pharmaceutical,
agrochemical and electronic products.
A. Henne et al., J. Amel: Chem. Soc., Vol. 69, pp. 1819-1 820 (1 947) discloses a process for
preparing 1,1,1,5,5,5-hexafluoroacetyl acetone which involves a copper complex and
hydrogen sulphide in ether. A very similar process is disclosed in U.S. Patent No. 6,046,364.
The processes disclosed in prior art have many disadvantages like poor yield and industrially
non-compliant due to high effluent load.
U.S. Patent Nos. 6,392,101 and 6,384,286 disclose processes for producing 1,1,1,5,5,5-
hexafluoroacetyl acetone involving reaction of 1,1,1 trifluoroacetone and ester of
trifluoroacetic acid, followed by the addition of water and 24% su1furi.c acid to obtain an
dihydrate intermediate. Further, this dihydrate intermediate is purified to obtain 1,1,1,5,5,5 -
hexafluoroacetyl acetone. The multistep work-up and many process operations of the
reaction results in poor yield. Additionally, poor recovery of hydrate from aqueous solution
results in high effluent load.
Japanese Patent Application No. 2001261 607 discloses the process for producing1 ,l ,1,5,5,5-
hexafluoroacetyl acetone by hydrolysis of 1,1,1,5,5,5-hexafluoroacetyl acetone metal
complex and dehydration of the resulting 1,1,1,5,5,5-hexafluoroacetyl acetone dihydrate.
Chinese Patent No. 102260151 provides a process for the preparation of 1,1,1,5,5,5-
hexafluoroacetylacetone which comprises of reaction of trifluoroacetic anhydride with
trifluoroacetoacetate in the presence of a catalyst. Although, these processes involves cheap
raw materials, but suffer in terms of multistep work-up and many process operations which
result in poor yield.
Thus, there is a need in the art for an economically viable, energy efficient and high output
alternative way to prepare 1,1,1,5,5,5 tetrafluoro acetyl acetone.
OBJECTIVE OF THE INVENTION
The main objective of the present invention is to provide a process for preparation of
1,1,1,5,5,5-hexafluoroacetyl acetone.
SUMMARY OF THE INVENTION
An aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with allcyl trifluoroacetate in the presence of a base,
wherein "alkyl" is CI-C4 alkyl group
b) contacting the product obtained from step a) with an acid, and
c) isolating the 1,1,1,5,5,5 hexafluoroacetyl acetone from the step b) reaction mixture,
wherein steps a), b) and c) are carried out under anhydrous conditions.
Another aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a base,
wherein "alkyl" is CI-C4 alkyl group and .
b) contacting the product obtained from step a) with an acid to obtain 1,1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot.
Another aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a base,
wherein "alkyl" is C1-C4 alkyl group and
b) contacting the product obtained from step a) with an acid to obtain 1;1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot under
anhydrous conditions.
DETAILED DESCRIPTION OF THE INVENTION
An aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a base,
wherein "alkyl" is C1-C4 alkyl group
b) contacting the product obtained from step a) with an acid, and
c) isolating the 1,1,1,5,5,5 hexafluoroacetyl acetone from the step b) reaction mixture,
wherein steps a), b) and c) are carried out under anhydrous conditions.
Another aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a base,
wherein "alkyl" is CI-C4 alkyl group and
b) contacting the product obtained from step a) with an acid to obtain 1,1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot.
Another aspect of the present invention provides a process for producing 1,1,1,5,5,5
hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a
base, wherein "alkyl" is C1-C4 alkyl group and
b) contacting the product obtained from step a) with an acid to obtain 1,1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot under
anhydrous conditions.
The reaction of 1,1,1 trifluoro acetone and alkyl trifluoroacetate is carried out in the
presence of a base. The reaction is carried out under anhydrous conditions. The base is
selected from alkali metal, alkali metal alkoxide and alkali metal hydride or mixture thereof.
The alkali metal may be selected from sodium, potassium, rubidium and cesium. The alkali
metal alkoxide may be selected from sodium methoxide, sodium ethoxide, potassium
methoxide and potassium ethoxide. The alkali metal hydride may be selected from sodium
hydride and potassium hydride. The reaction of 1,1,1 trifluoro acetone and alkyl
trifluoroacetate in the presence of a base may be carried out at a temperature range of about
0°C to about 100°C, for example, about 10°C to about 70°C. The reaction may take place in
presence an aprotic organic solvent selected from the group consisting of methyl tert butyl
ether, monoglyme, diglyme, cyclohexane, toluene, xylene, diethyl ether, diisopropyl ether
and dioxane or mixtures thereof. The reaction of 1,1,1 trifluoro acetone . and alkyl
trifluoroacetate is carried out in the presence of a base to provide an alkali metal salt of
1,1,1,5,5,5-hexafluoroacetyl acetone. The alkali metal salt of 1,1,1,5,5,5-hexafluoroacetyl
acetone may be isolated from the reaction mixture or may be carried on to next step without
isolation.
The "alkyl" represents C ,-C4 alkyl group.
The "one pot" means step a) and b) are carried out in the same reaction pot/vessel, essentially
without isolating the intermediate obtained from step a).
The "anhydrous condition" means condition which contain no water.
The alkali metal salt of 1,1,1,5,5,5-hexafluoroacetyl acetone is treated with an acid to
obtain 1,1,1,5,5,5 hexafluoroacetyl acetone. The treatment with an acid is carried out under
anhydrous conditions. An acid may be selected from an inorganic acid or an organic acid. An
inorganic acid may be selected from hydrochloric acid, sulphuric acid and chlorosulfonic
acid or mixture thereof. An organic acid may be selected from trifluoroacetic acid, methane
sulfonic acid and p-toluene sulfonic acid or mixture thereof. An acid may be in anhydrous
solution form or in gaseous form. The treatment of 1,1,1,5,5,5-hexafluoroacetyl acetone
treated with an acid may be carried out at a temperature range of about O°C to about 60°C.
The treatment of 1,1,1,5,5,5-hexafluorohcetyla cetone treated with an acid may be carried out
in presence of an aprotic solvent, for example, hexane, cyclohexane, toluene xylene, mono
glyme, diglyme and dioxane or mixtures thereof.
The 1,1,1,5,5,5-hexafluoroacetyl acetone is isolated from the reaction mixture by any of the
methods in the art, for example, evaporation, distillation, crystallization, filtration and layer
separation or mixture thereof.
The 1,1,1,5,5,5-hexafluoroacetyl acetone, obtained by process disclosed in present invention,
has high purity about 98% to about 99%.
The present invention may be carried out in continuous mode.
The following examples are given by way of illustration of the present disclosure and should
not be construed to limit the scope of present disclosure. It is to be.understood that both the
foregoing general description and the following detailed description are exemplary and
explanatory only and are intended to provide further explanation of the. subject matter.
EXAMPLES
1: Preparation of 1,1,1,5,5,5-hexafluoroacetyl acetone
The sodium ethoxide (122 g) and toluene (215 g) were taken together in a round bottom
flask. A mixture of 1,1,1-trifluoroacetone (200 g) and ethyl trifluoroacetate (280 g) was
added to the reaction flask at 20°C to 30 OC. The reaction mixture was stirred and monitored
for 6 hours. The toluene was distilled off from the reaction mixture partially to obtain sodium
salt of 1,1,1,5,5,5-hexafluoroacetyla cetone. The sodium salt of 1,1,1,5,5,5-hexafluoroacetyl
acetone was filtered, dried under vacuum. The anhydrous sulphuric acid (438 g, 98%) was
added to the reaction vessel and sodium salt of 1,1,1,5,5,5-hexafluoroacetyl acetone was
added to the reaction vessel at 30°C to 40°C. The reaction mass was stirred for three hours
and title compound was distilled.
Yield: 3 16 g
2: Preparation of 1,1,1,5,5,5-hexafluoroacetyl acetone
The sodium ethoxide (66 g) and toluene (145 g) were taken together in a round bottom flask.
A mixture of 1 , 1 , 1 -trifluoroacetone (100 .g) and ethyl trifluoroacetate (1 40 g) was added to
the reaction flask at 20°C to 30 OC. The reaction mixture was stirred and monitored for 6
hours. The toluene was distilled off from the reaction mixture partially to obtain sodium salt
of 1,1,1,5,5,5-hexafluoroacetyl acetone suspended in toluene. The anhydrous sulphuric acid
(220 g, 98%) was added to the reaction vessel to containing suspended sodium salt of
1,1,1,5,5,5-hexafluoroacetyl acetone at 30°C to 40°C. The reaction mass was stirred for three
hours and title compound was distilled.
Yield: 167 g
Purity: 98.5%

We claim:
1. A process for producing 1,1,1,5,5,5 hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a
base,
wherein "alkyl" is C1-C4 alkyl group
b) contacting the product obtained from step a) with an acid, and
c) isolating the 1,1,1,5,5,5 hexafluoroacetyl acetone from the step b) reaction
mixture, wherein steps a), b) and c) are carried out under anhydrous conditions.
2. The process according to claim 1, wherein step a) base is selected from alkali metal,
alkali metal alkoxide and alkali metal hydride or mixture thereof.
3. The process according to claim 2, where in the alkali metal is selected from sodium,
potassium, rubidium and cesium; the alkali metal alkoxide is selected from sodium
methoxide, sodium ethoxide, potassium methoxide and potassium ethoxide and the
alkali metal hydride is' selected from sodium hydride and potassium hydride.
4. A process for producing 1,1,1,5,5,5 hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a
base, wherein "alkyl" is CI-C4 alkyl group, and
b) contacting the product obtained from step a) with an acid to obtain 1,1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot.
5. A process for producing 1,1,1,5,5,5 hexafluoroacetyl acetone comprising:
a) reacting 1,1,1 trifluoro acetone with alkyl trifluoroacetate in the presence of a
base, wherein "alkyl" is C1-C4 alkyl group, and
b) contacting the product obtained from step a) with an acid to obtain 1,1,1,5,5,5
hexafluoroacetyl acetone, wherein steps a) and b) are carried out in one pot under
anhydrous conditions.
6. The process according to claims 1, 4 and 5, wherein an acid is selected from an
inorganic acid or an organic acid.
7. The process according to claim 6, wherein an inorganic acid is selected from
hydrochloric acid, sulphuric acid and chlorosulfonic acid or mixture thereof; an
organic acid may be selected from trifluoroacetic acid, methane sulfonic acid and ptoluene
sulfonic acid or mixture thereof.
8. The process according to claims 1, 4 and 5, wherein an acid may be in anhydrous
solution form or in gaseous form.
9. The process according to claims 1, wherein 1,1,1,5,5,5-hexafluoroacetyl acetone is
isolated from the reaction mixture by evaporation, distillation, crystallization,
filtration and layer separation or mixture thereof.