Process for producing iodotrifluoromethane

A novel process for producing iodotrifluoromethane is provided which comprises reacting trifluoromethane with iodine in the presence of oxygen by use of a catalyst containing a salt of a metal supported by a carbonaceous carrier. In this process, the catalyst life is lengthened greatly, the by-product is decreased, and the unreacted iodine can be recovered efficiently as high-purity iodine to be recycled without purification.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a process for producing 
iodotrifluoromethane. More specifically, the present invention relates to 
a process for producing iodotrifluoromethane by reacting trifluoromethane 
with iodine in the presence of oxygen by use of a catalyst comprising a 
metal salt supported on a carbonaceous carrier. 
2. Description of the Related Art 
Iodotrifluoromethane is not only promising as a fire extinguisher 
substituting for Halon 1301 and Halon 1211, but also highly useful as a 
fluorine-containing intermediate compound for introducing a 
trifluoromethyl group in production of surfactants, agricultural 
chemicals, pharmaceuticals, and the like. Halon 1301, Halon 1211, and the 
like conventional fire extinguishers destroy the ozone layer, or cause 
global temperature rise by a greenhouse effect. Use of such extinguishers 
are being prohibited by environmental protection laws. On the other hand, 
the iodotrifluoromethane, which has a significantly shorter life in the 
air, causes negligibly the ozone layer destruction and the global 
temperature elevation. Therefore, the iodotrifluoromethane is promising 
for use as the fire extinguisher. 
Several processes are known for production of iodotrifluoromethane. For 
example, J. Chem. Soc. 1951 p.584, and J. Org. Chem. 1967 p.833 disclose 
processes of reacting an alkali metal trifluoroacetate or silver 
trifluoroacetate with iodine; and J. Org. Chem. 1958 p.2016, and 
JP-A-2-262529 disclose processes of reacting a trifluoroacetyl halide with 
potassium iodide or lithium iodide. 
Any of the above known methods employs expensive trifluoroacetic acid or 
its derivative as the source material. Moreover, use of alkali 
trifluoroacetate as the source material requires complete elimination of 
water including water of crystallization from the reaction system, and yet 
the yield is as low as about 70%. The expensive silver trifluoroacetate, 
although it gives a higher yield, is not necessarily advantageous to an 
industrial process. 
JP-A-52-68110 discloses a process for producing iodotrifluoromethane in 
which trifluoromethane is reacted with iodine in the presence of a 
catalyst comprising an alkali metal salt or an alkaline earth metal salt 
supported by active carbon or active alumina. This process was replicated 
carefully by the inventors of the present invention. Consequently, it was 
found that, in the disclosed process, carbon deposition occurs, lowering 
significantly the catalyst activity in one or two days of the reaction, 
and the recovered iodine contains significant amount of a paste-like 
impurity estimated to be a high polymer. This recovered iodine cannot 
readily be purified, and complicated equipment is required for 
purification of the recovered iodine for recycling. Therefore, this 
process is not applicable to an industrial production. 
As described above, the disclosed processes of production of 
iodotrifluoromethane from trifluoroacetic acid or its derivative are 
disadvantageous in that the source material is expensive, and use of more 
expensive silver salt of the trifluoroacetic acid is required for 
improving the yield. The conventional process of production of 
iodotrifluoromethane from trifluoromethane is also disadvantageous in that 
the catalyst life is short owing to carbon deposition, and the process 
requires a complicated equipment for eliminating a large amount of 
paste-like impurity from the recovered iodine for recycling it. 
Therefore, a novel process for producing iodotrifluoromethane is demanded 
to overcome the disadvantages. 
Under such circumstances, the inventors of the present invention made 
comprehensive studies on the process for producing iodotrifluoromethane by 
reaction of trifluoromethane with iodine. As the results, it was found 
that the reaction of trifluoromethane with iodine can be conducted with a 
long catalyst life in the presence of a catalyst comprising a metal salt 
supported on a carbonaceous carrier with coexistence of oxygen, and that 
the iodine which has not been converted to iodotrifluoromethane and 
by-product iodopentafluoroethane is recovered in a high purity without a 
paste-like impurity at a high recovery ratio and can be recycled without 
purification. The present invention is accomplished on the basis of the 
above findings. 
SUMMARY OF THE INVENTION 
The present invention intends to provide a process for producing 
iodotrifluoromethane applicable to industrial production with less amount 
of by-products at a low cost. 
The process for producing iodotrifluoromethane of the present invention 
comprises reacting trifluoromethane with iodine in the presence of oxygen 
by use of a catalyst containing a metal salt supported on a carbonaceous 
carrier. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The catalyst system comprising a metal salt supported by a carbonaceous 
carrier according to the present invention exhibits high performance, 
retaining high activity for a long term and giving high conversion and 
high selectivity. The coexistence of oxygen with the catalyst of the 
present invention enables efficient production of iodotrifluoromethane by 
simple reaction of trifluoromethane with iodine. In the present invention, 
the iodine fed to the reaction system is converted to the 
iodotrifluoromethane and by-product iodopentafluoroethane, and the 
unreacted iodine is recovered as high-purity iodine by simple cooling of 
the reaction mixture. 
The present invention is described below more specifically. 
The catalyst employed in the present invention is a metal salt supported by 
a carbonaceous carrier. 
The carbonaceous carrier in the present invention includes active carbon, 
graphite, fibrous active carbon, and carbon molecular sieves. 
The carbonaceous carrier may be a mixture of the above carbonaceous 
materials, if necessary. The carbonaceous carrier is preferably in a shape 
of powder, particles, lumps, or the like, preferably in a shape of 
spheres, columns, tablets, or particles in a size ranging from about 2 to 
about 15 mm, but is not limited thereto. 
The carbonaceous carrier may be treated by nitric acid, hydrochloric acid, 
phosphorus acid, or the like for eliminating impurities such as ash, if 
necessary. 
Incidentally, alumina, silica, and titania, which are employed generally as 
the catalyst carrier, are not preferred since they will give low activity 
of the catalyst in forming iodotrifluoromethane or they can be decomposed 
under the reaction conditions of the present invention. 
The metal for the catalyst of the present invention includes an alkali 
metal and/or an alkaline earth metal; and combinations of an alkali metal 
and a noble metal, an alkaline earth metal and a noble metal, and an 
alkali metal, an alkaline earth metal and a noble metal. 
The alkali metal includes lithium, sodium, potassium, rubidium, and cesium. 
Of these, potassium, rubidium, and cesium are preferred. The metals may be 
used singly or in combination. More preferably, a combination of potassium 
and cesium, or potassium and rubidium is used. 
The alkaline earth metal includes beryllium, magnesium, calcium, strontium, 
and barium. Of these, magnesium, calcium, barium, and/or mixtures thereof 
are preferred. The alkaline earth metal may be used in combination with an 
alkali metal. A combination of alkali metal and magnesium as the alkaline 
earth metal is particularly preferred. 
The noble metal employed in the present invention includes platinum, 
ruthenium, rhodium, palladium, and iridium. These noble metals may be used 
singly or in combination. Of these noble metals, platinum and rhodium are 
preferred. The noble metal may be used in combination with an alkali 
metal, with an alkaline earth metal, or with an alkali metal and an 
alkaline earth metal. Of the combinations of the metals, preferred are 
combinations of an alkali metal with a noble metal, more preferred are a 
combination of potassium, cesium, and platinum; and a combination of 
potassium, rubidium, and platinum. 
The metal is supported, in the present invention, as a salt on a 
carbonaceous carrier. The salt of the alkali metal, the alkaline earth 
metal, or the noble metal is usually selected from metal salt-forming 
substances such as hydroxides, halides, nitrates, carbonates, 
carboxylates, alkoxides, and the like in consideration of the solubility 
in the solvent, the ease of handling, commercial availability as the 
reagent, the stability, the behavior in the drying process and the thermal 
decomposition process. 
The method of depositing the above metal salt onto the carbonaceous carrier 
is not specially limited in the present invention. The salt may be 
deposited by a conventional method for preparing a supported catalyst such 
as an impregnation method, a precipitation method, and a kneading method. 
Of these deposition methods, the impregnation method is preferred in 
consideration of the simplicity of the process and production cost. 
The impregnation method may be conducted, for example, as follows. Firstly, 
a prescribed amount of the metal salt is dissolved in a solvent at room 
temperature or, if necessary, at an elevated temperature. The solvent may 
be selected from water, organic solvents, and mixtures thereof. The 
organic solvents include alcohols, ketones, ethers, and aromatic 
compounds. Of these solvents, water, methanol, and acetone are preferred 
in consideration of the cost and the safety. The amount of the solvent to 
be used depends largely on the kinds of the carbonaceous carrier, the 
metal salt, and the solvent, and cannot specially be limited. For example, 
when active carbon is used as the carrier, the solvent is used suitably in 
an amount ranging from 50 to 1000 mL for 100 g of the active carbon. 
Secondly, in the impregnation method, a prescribed amount of the 
carbonaceous carrier is immersed into the solution containing a metal 
salt. The immersion is continued for two hours or longer, overnight 
standing being acceptable. If the whole of the solution has been absorbed 
during the immersion, the carrier is directly dried preliminarily in a 
conventional drier at a temperature from 80.degree. to 150.degree. C. If 
some of the solution remains unabsorbed, the solvent is evaporated in a 
flask on a water bath, or by a rotary evaporator with gradual pressure 
reduction, and then the carrier is preliminarily dried as above by a 
drier. In the case where two or more kinds of salts selected from alkali 
metals and alkaline earth metals are deposited, the metal salts may be 
dissolved in one and the same solvent and are deposited simultaneously in 
a manner described above. On the other hand, in the case where an alkali 
metal and/or an alkaline earth metal, and a noble metal is deposited, 
preferably the deposition is conducted separately in succession, more 
preferably the noble metal firstly and the alkali metal and/or the 
alkaline earth metal subsequently, in the present invention. 
After the deposition of the metal salt onto the carbonaceous carrier, the 
carrier is further dried and calcined before use as the catalyst in the 
present invention. The drying and the calcination may be conducted either 
in separate steps or in one step. The conditions for the drying and the 
calcination depend largely on the metal, the carrier, and the deposition 
method, and cannot specially be limited. For example, for the drying and 
the calcination, the preliminarily dried metal-supporting carrier is 
filled into a reaction tube, dried at 100.degree.-200.degree. C. for 1-3 
hours with introduction of an inert gas like nitrogen or argon, and then 
calcined at 400.degree.-750.degree. C. for 1-5 hours. The calcination at 
the temperature above 750.degree. C. is liable to cause undesired 
aggregation or evaporation of the metal salt to cause drop of the catalyst 
activity disadvantageously. 
The amount of the metal deposited on the carbonaceous carrier ranges from 
0.1% to 50% by weight of the entire catalyst weight in the present 
invention. At the amount of less than 0.1% by weight, sufficient catalyst 
activity cannot be achieved, whereas at the amount of more than 50% by 
weight, the excess metal is not effective in improving the catalyst 
activity. 
The atomic ratio of the noble metal to the alkali metal and/or alkaline 
earth metal ranges from 0.001 to 1.0 in the present invention. At the 
ratio of lower than 0.001, the effect of the noble metal for lengthening 
the catalyst life is little, whereas at the ratio of higher than 1.0, the 
catalyst cost is high owing to the expensiveness of the noble metal, 
undesirably. 
The source materials employed in the present invention are 
trifluoromethane, iodine, and oxygen. The purity of the trifluoromethane 
is not specially limited, but is preferably not lower than 97%. The iodine 
may be a commercial product. The oxygen may be pure oxygen, or air. The 
oxygen may be diluted, if necessary, with an inert gas such as nitrogen, 
helium, and argon. 
The style or method of the reaction process is not specially limited. The 
reaction may be conducted in a reactor of a fixed bed type, a fluidized 
bed type, or a moving bed type in the present invention. From the 
simplicity of the production process, the fixed bed is preferred. The 
reaction with the fixed bed type reactor is conducted, for example, as 
below. A gaseous mixture of the source materials are fed continuously to 
the reactor filled with the catalyst prepared as above and maintained at a 
prescribed reaction temperature. In formation of the gas mixture, the 
iodine which is solid ordinarily is melted by heating, and into the molten 
iodine, gaseous trifluoromethane is introduced in bubbles to form a 
gaseous mixture of trifluoromethane and iodine. Thereto oxygen is added. 
Thus the prescribed amount of iodine can be fed to the reaction system. 
The molar ratio of the iodine to the trifluoromethane employed in the 
present invention ranges from 0.05 to 10, preferably from 0.05 to 3. At 
the molar ratio lower than 0.05, the selectivity is low, whereas at the 
molar ratio of higher than 10, the unreacted iodine to be recovered 
increases, which is disadvantageous industrially. 
The volume ratio of the oxygen to the trifluoromethane employed in the 
present invention ranges from 0.01 to 1.0. At the volume ratio lower than 
0.01, the catalyst activity deteriorates remarkably rapidly to shorten the 
catalyst life, and the purity of the solid iodine separated after the 
reaction is lower. On the other hand, at the molar ratio higher than 1.0, 
the carbonaceous carrier of the catalyst tends to burn disadvantageously. 
The reaction temperature in the present invention ranges from 300.degree. 
to 750.degree. C., preferably from 400.degree. to 600.degree. C. At the 
reaction temperature lower than 300.degree. C., the reaction velocity is 
extremely low, whereas at the reaction temperature higher than 750.degree. 
C., decomposition of the formed iodotrifluoromethane occurs 
disadvantageously. 
The reaction pressure in the present invention is not specially limited, 
but the pressure is not lower than atmospheric pressure and is not higher 
than 2 MPa in consideration of the properties of the source materials and 
the formed products. 
The construction material for the reaction apparatus includes carbon steel, 
cast iron, stainless steel, copper, nickel, and Hastelloy. However, carbon 
steel, cast iron, stainless steel, copper, and nickel can be corroded to 
cause scale formation. Therefore, Hastelloy is preferred as the 
construction material for the reaction tube and related apparatus exposed 
to the reaction temperature in the present invention. 
In the process of the present invention, the reaction gas mixture 
discharged from the reaction tube is cooled, and is separated into a gas 
and a solid. The gas is distilled under pressure in a conventional manner 
to separate the formed iodotrifluoromethane from the unreacted 
trifluoromethane. The unreacted trifluoromethane is recovered and recycled 
to the reaction system. The iodotrifluoromethane is the intended final 
product. The distillation may be conducted either by a batch system or a 
continuous system. On the other hand, the separated solid is unreacted 
iodine. The unreacted iodine herein means the iodine which has not been 
converted to the intended iodotrifluoromethane or the by-products such as 
iodopentafluoroethane. It is characteristic to the present invention that 
the unreacted iodine can be recovered efficiently as high-purity iodine, 
and the recovered iodine can be recycled directly without purification. 
Industrially, the iodine is recovered by a gas-solid separation column 
equipped with a scraper, and the recovered iodine can be recycled directly 
to the iodine evaporator, requiring no troublesome purification process. 
Therefore, the process is simple and economical. 
On the other hand, in the absence of the oxygen, or with a non-carbonaceous 
carrier, the recovered iodine contains the paste-like impurity estimated 
to be a high polymer in a large amount. The recovery of the iodine was 
tried by distillation or sublimation. Thereby, it was found that the 
iodine recovery ratio is as low as about 73% to about 80% owing to the 
paste-like impurity, and the recycling of the recovered iodine without 
purification to the reaction system resulting in remarkable drop in the 
conversion of trifluoromethane, the selectivity and yield of 
iodotrifluoromethane. 
The present invention is described more specifically by reference to 
examples without limiting the invention. 
For simplicity, the source materials and the products are abbreviated as 
shown below: 
Trifluoromethane: CHF.sub.3 
Oxygen: O.sub.2 
Iodine : I.sub.2 
Iodotrifluoromethane: CF.sub.3 I 
Iodopentafluoroethane: C.sub.2 F.sub.5 I 
Tetrafluoromethane : CF.sub.4 
The conversion ratio, and the selectivity shown in the examples are defined 
as below. 
Conversion ratio (%) 
=(Moles of converted CHF.sub.3)/(Moles of fed CHF.sub.3)!.times.100 
Selectivity (%) 
=(Moles of product)/(Moles of converted CHF.sub.3)!.times.100

EXAMPLE 1 
Catalyst Preparation! 
(1) Preparation of Catalyst Supported by Active Carbon: 
(a) A prescribed amount of a noble metal salt was dissolved in 400 g of 
water. Thereto, 300 g of active carbon was added, and immersed overnight. 
The noble metal salt solution was entirely absorbed by the active carbon 
without leaving an unabsorbed solution. This active carbon was transferred 
to a vat, and was preliminarily dried in a drier at a temperature of 
90.degree. to 110.degree. C. for 6 hours. 
(b) A prescribed amount of an alkali metal salt and/or an alkaline earth 
metal salt was dissolved in 400 g of water. Thereto, the active carbon 
treated in the above step (a) was added, and immersed overnight. After the 
immersion, a small amount of the solution of the alkali metal salt and/or 
the alkaline earth metal salt remained unabsorbed. This mixture was 
treated by a rotary evaporator with gradual pressure reduction to remove 
water. 
(c) The active carbon was transferred to a vat, and dried preliminarily in 
a drier at a temperature of from 90.degree. to 110.degree. C. for 6 hours. 
The preliminarily dried active carbon was transferred to a heating 
furnace, and further, under a nitrogen stream, dried at 150.degree. C. for 
one hour and calcined at 550.degree. C. for one hour to obtain a catalyst. 
A catalyst containing no noble metal salt was prepared by conducting the 
above steps (b) and (c) without conducting the step (a). 
(2) Preparation of Catalyst Supported on Graphite or Carbon Molecular 
Sieve: 
The catalyst was prepared in the same manner as the above steps (1)-(b) and 
(l)-(c). 
(3) Preparation of Catalyst Supported on Active Alumina, Silica, or 
Titania: 
The catalyst was prepared in the same manner as in the preparation (2) 
above. 
The metal salts were commercial reagents. The carbonaceous carriers 
employed were as shown below. 
Active Carbon: Shirasagi C2 
(Takeda Chemical Industries, Ltd.) 
Graphite: Press-molded product of graphite powder 
(Wako Pure Chemical Industries, Ltd.) 
Carbon Molecular Sieve: Molsievon 
(Takeda Chemical Industries, Ltd.) 
Active Alumina: KHS-46 (Sumitomo Chemical Co. Ltd.) 
Silica: CARiACT-Q-50 (Fuji Silicia K.K.) 
Titania: CS-300-24 (Sakai Kagaku K.K.) 
Table 1 shows the prepared catalysts and the amounts of the supported 
metals. 
EXAMPLES 2-5 
Into a reaction tube of inside diameter of 25 mm made from Hastelloy C, was 
filled 100 mL of Catalyst A, B, C, or D prepared in Example 1. The 
reaction tube was heated, and a gas mixture composed of CHF.sub.3, 
I.sub.2, and O.sub.2 was fed into the reaction tube at the feed rate at 
the reaction temperature shown in Table 2. The gas after the reaction was 
cooled by passing a cooling tube to separate a solid matter from the gas. 
The gas was analyzed by gas chromatography. Table 3 shows the results of 
analysis of the reaction gases after lapse of the prescribed times from 
the start of the reaction. The solid matter separated from the reaction 
gas by cooling was a blackish violet plate- shaped crystalline matter 
having metallic luster in any of Examples 2-5. The recovered solids 
contained respectively iodine at a content of not lower than 98% by 
analysis of iodine according to JIS K8920. 
Table 3 shows that the catalysts comprising the alkali metal salt and the 
noble metal salt, or the alkali metal salt, the alkaline earth metal salt 
and the noble metal salt, supported by active carbon had high activity, 
high selectivity, and long life. 
EXAMPLES 6-8 
The reaction was conducted with Catalyst E, F, or G prepared in Example 1 
under the conditions shown in Table 2. The results are shown in Table 3. 
The solid matter separated from the reaction gas by cooling was a blackish 
violet plate-shaped crystalline matter having metallic luster in any of 
Examples 6-8. The recovered solids contained respectively iodine at a 
content of not lower than 98% by analysis of iodine in the same manner as 
in Examples 2-5. 
Table 3 shows that the catalysts comprising the alkali metal salt, the 
alkaline earth metal salt and the noble metal supported by active carbon 
exhibited high activity, high selectivity, and a long life. 
EXAMPLES 9-12 
The reaction was conducted with Catalyst H, I, J, or K prepared in Example 
1 under the conditions shown in Table 2. The results are shown in Table 3. 
The solid matter separated from the reaction gas by cooling was a blackish 
violet plate-shaped crystalline matter having metallic luster in any of 
Examples 9-12. The recovered solids contained respectively iodine at a 
content of not lower than 98% by analysis of iodine in the same manner as 
in Examples 2-5. 
Table 3 shows that, of the the alkali metal salts supported on active 
carbon, the potassium salt catalyst exhibited high selectivity, and the 
cesium salt catalyst exhibited high activity, while the alkaline earth 
metal salt catalysts had low activity. 
EXAMPLES 13 
The reaction was conducted with Catalyst F prepared in Example 1 and by use 
of air instead of oxygen under the conditions shown in Table 2. The 
results are shown in Table 3. The solid matter separated from the reaction 
gas by cooling was a blackish violet plate-shaped crystalline matter 
having metallic luster. The recovered solids contained iodine at a content 
of not lower than 98% by analysis of iodine in the same manner as in 
Examples 2-5. 
EXAMPLE 14-16 
The reaction was conducted with Catalyst L (graphite), M (graphite), or N 
(carbon molecular sieve) prepared in Example 1 under the conditions shown 
in Table 2. The results are shown in Table 3. Any of the solid matters 
separated from the reaction gas by cooling was a blackish violet 
plate-shaped crystalline matter having metallic luster in any of Examples 
14-16. The recovered solids contained respectively iodine at a content of 
not lower than 98% by analysis of iodine in the same manner as in Examples 
2-5. 
EXAMPLES 17-18 
The reaction was conducted in the same manner as in Example 2 except that 
the black plate-shaped iodine having metallic luster recovered in Example 
2 or Example 4 was used without treatment as the iodine source material. 
The results were nearly the same as in Example 2. 
Comparative Examples 1-4 
The reaction was conducted with Catalyst E, F, or H (active carbon), or M 
(graphite) prepared in Example 1 without addition of oxygen under the 
conditions shown in Table 2. The results are shown in Table 3. The 
catalyst life was significantly short in the absence of oxygen. The solid 
matter separated from the reaction gas contained a paste-like impurity 
estimated to be a high polymer. The recovery of the iodine therefrom by 
distillation or sublimation was particularly difficult. The solid matter 
contained iodine at a content of 72% to 85% in any of the Comparative 
Examples 1-4. 
Comparative Example 5 
The reaction was conducted with Catalyst O (active alumina) prepared in 
Example 1 without addition of oxygen under the conditions shown in Table 
2. The results are shown in Table 3. The intended reaction did not proceed 
with the catalyst employing active alumina as the carrier. 
Comparative Examples 6-8 
The reaction was conducted with Catalyst O (active alumina), P (silica), or 
Q (titania) prepared in Example 1 under the conditions shown in Table 2. 
The results are shown in Table 3. The intended reaction did not proceed 
with the catalyst supported by the carrier other than the carbonaceous 
carrier even with coexistence of oxygen. The solid matter separated from 
the reaction gas was a blackish brown muddy solid and not readily scraped 
out from the gas-solid separator in any of Comparative Examples 6-8. The 
iodine content in the solid matter was in the range of 85% to 93% as 
measured in the same manner as in Examples 2-5. 
Comparative Example 9 
The reaction was conducted in the same manner as in Comparative Example 1. 
After 50 hours from the start of the reaction, the feed of CHF.sub.3 and 
I.sub.2 was stopped with the reaction conditions kept unchanged, and 
nitrogen (120 mL/min) and oxygen (8 mL/min) were fed in place of CHF.sub.3 
and I.sub.2 for 5 hours to the reactor for the purpose of reactivation of 
the catalyst. Thereafter, CHF.sub.3 and I.sub.2 were fed under the 
conditions of Comparative Example 1 for the reaction. However, the 
catalyst activity was not restored by the above reactivation operation. 
In production of iodotrifluoromethane by reaction of trifluoromethane and 
iodine according to the present invention, the catalyst has remarkably 
long life with the catalyst activity and the selectivity retained by 
conducting the reaction in the presence of oxygen with a catalyst 
comprising a metal salt supported by a carbonaceous carrier. In this 
process, the unreacted iodine which has not been converted to 
iodotrifluoromethane or iodopentafluoroethane can be recovered entirely as 
high-purity iodine, and be recycled without purification. Thus, the 
present invention provides a low-cost simple process for producing 
iodotrifluoromethane in comparison with conventional processes which 
employ expensive trifluoroacetic acid or its derivative as the source 
material, and is highly useful industrially. 
TABLE 1 
______________________________________ 
Amount of 
Supported metal supported 
Catalyst 
Carrier component (wt %) 
______________________________________ 
A Active carbon 
KNO.sub.3 1.7 
CsNO.sub.3 
5.8 
H.sub.2 PtCl.sub.6 
0.5 
B Active carbon 
KNO.sub.3 2.35 
RbNO.sub.3 
5.15 
H.sub.2 PtCl.sub.6 
0.5 
C Active carbon 
KNO.sub.3 6.7 
Mg(NO.sub.3).sub.2 
0.8 
H.sub.2 PtCl.sub.6 
1.0 
D Active carbon 
KNO.sub.3 7.5 
H.sub.2 PtCl.sub.6 
1.0 
E Active carbon 
KNO.sub.3 1.7 
CsNO.sub.3 
5.8 
F Active carbon 
KNO.sub.3 2.35 
RbNO.sub.3 
5.15 
G Active carbon 
KNO.sub.3 6.7 
Mg(NO.sub.3).sub.2 
0.8 
H Active carbon 
KF 7.5 
I Active carbon 
CsCl 7.5 
J Active carbon 
Mg(NO.sub.3).sub.2 
7.5 
K Active carbon 
Ba(NO.sub.3).sub.2 
7.5 
L Graphite KNO.sub.3 2.35 
RbNO.sub.3 
5.15 
M Graphite RbNO.sub.3 
7.0 
Mg(NO.sub.3).sub.2 
0.5 
N Carbon molecular 
KNO.sub.3 1.7 
sieve RbNO.sub.3 
2.1 
Mg(NO.sub.3).sub.2 
0.4 
O Active alumina 
KNO.sub.3 1.7 
CsNO.sub.3 
5.8 
H.sub.2 PtCl.sub.6 
0.5 
P Silica KF 7.5 
Q Titania KF 7.5 
______________________________________ 
TABLE 2 
______________________________________ 
Reaction 
temper- CHF.sub.3 
I.sub.2 
O.sub.2 
Air I.sub.2 /CHF.sub.3 
O.sub.2 /CHF.sub.3 
ature (mL/ (mL/ (mL/ (mL/ (molar 
(volume 
(.degree.C.) 
min) min) min) min) ratio) 
ratio) 
______________________________________ 
Example 
2-4 550 80 40 8 -- 0.5 0.1 
5 475 80 24 16 -- 0.3 0.2 
6-8 550 80 40 8 -- 0.5 0.1 
9 475 80 24 16 -- 0.3 0.2 
10-12 550 80 40 8 -- 0.5 0.1 
13 550 80 24 -- 80 0.3 0.2 
14-16 550 20 20 2 -- 1.0 0.1 
Comparative example 
1-2 550 80 40 -- -- 0.5 -- 
3 475 80 24 -- -- 0.3 -- 
4 550 20 20 -- -- 1.0 -- 
5 550 20 20 -- -- 1.0 -- 
6-8 550 20 20 2 -- 1.0 0.1 
______________________________________ 
TABLE 3 
______________________________________ 
Reaction 
time CHF.sub.3 CF.sub.3I 
Cata- lapse Conversion 
Selectivity (%) 
Yield 
lyst (min) (%) CF.sub.3 I 
CF.sub.4 
C.sub.2 F.sub.5 I 
(%) 
______________________________________ 
Example 
2 A 10 73.2 38.3 5.0 2.1 28.0 
250 72.1 39.5 4.6 1.9 28.5 
600 70.9 40.1 3.9 1.6 28.4 
3 C 10 63.2 48.2 5.2 2.4 30.5 
250 62.7 48.6 4.9 2.3 30.5 
600 60.9 49.2 4.4 2.2 30.0 
4 D 10 48.9 40.1 3.5 2.6 19.6 
250 48.6 41.2 3.3 2.7 20.0 
600 47.2 42.6 3.1 2.5 20.1 
5 B 10 46.8 65.7 2.0 1.7 30.7 
250 45.1 65.5 1.9 1.6 29.5 
600 44.9 65.6 1.5 1.6 29.5 
6 E 10 72.4 38.1 8.1 1.9 27.6 
30 72.2 38.1 7.9 1.8 27.5 
50 72.1 38.3 7.6 1.8 27.6 
250 71.9 38.4 6.5 1.6 27.6 
600 32.4 53.9 2.6 1.3 17.5 
7 G 10 62.5 48.1 5.9 3.1 30.1 
250 61.4 48.4 5.7 3.0 29.7 
600 25.7 54.5 2.1 1.8 14.0 
8 F 10 45.1 65.9 2.1 1.6 29.7 
30 45.1 65.9 2.0 1.5 29.7 
50 44.8 65.7 2.0 1.3 29.4 
250 44.5 65.4 1.8 1.2 29.1 
600 25.6 65.6 1.5 1.1 16.8 
9 H 10 47.2 39.8 3.9 2.8 18.8 
30 47.0 39.9 3.8 2.8 18.8 
50 47.0 40.0 3.5 2.7 18.8 
250 46.7 40.3 3.2 2.5 18.8 
600 24.6 49.3 2.3 2.4 12.1 
10 I 10 72.4 21.3 16.4 2.5 15.4 
250 71.5 22.4 14.8 2.1 16.0 
11 J 10 14.5 64.5 9.7 2.4 9.35 
250 13.7 63.8 9.6 2.1 8.74 
12 K 10 26.5 43.1 8.2 2.2 11.4 
250 25.9 44.6 7.6 1.7 11.6 
13 F 10 80.0 35.6 17.5 1.3 28.5 
250 78.9 36.5 16.2 1.2 28.8 
14 L 5 46.7 55.6 1.2 0.2 26.0 
250 45.4 56.1 1.1 0.2 25.5 
15 M 5 66.9 50.1 3.4 1.1 33.5 
10 66.8 50.2 3.4 1.1 33.5 
30 66.2 50.5 3.4 1.1 33.4 
50 65.9 50.8 3.3 1.0 33.5 
250 64.5 51.2 3.1 0.9 33.0 
16 N 5 61.2 47.1 0.6 1.5 28.8 
250 59.2 48.4 0.7 1.4 28.7 
17 A 10 71.8 38.1 5.0 1.9 27.4 
250 71.4 39.3 4.2 1.5 28.1 
18 A 10 71.5 38.2 5.3 2.0 27.3 
250 71.0 39.4 4.0 1.6 28.0 
Comparative Example 
1 E 10 72.2 36.5 9.7 2.4 26.4 
30 71.1 37.1 9.5 2.3 26.4 
50 1.9 3.7 0.5 0.0 0.07 
2 H 10 44.3 38.7 3.7 2.8 17.1 
30 43.9 39.1 3.5 2.7 17.2 
50 1.2 2.1 0.0 0.0 0.03 
3 F 30 43.9 65.1 2.5 1.4 28.6 
50 0.2 1.2 0.0 0.0 0.002 
4 M 5 65.1 49.0 3.1 1.2 31.9 
10 0.5 1.8 0.0 0.0 0.009 
5 O 5 17.3 0.0 0.7 0.0 0.0 
10 5.5 0.0 0.2 0.0 0.0 
6 O 5 17.6 0.0 0.6 0.0 0.0 
10 8.2 0.0 0.3 0.0 0.0 
7 P 5 25.0 0.1 0.0 0.0 0.03 
10 8.6 0.6 0.0 0.0 0.05 
8 Q 5 25.4 0.0 0.0 0.0 0.0 
10 5.3 0.0 0.0 0.0 0.0 
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