JPH01172347A - Production of 1,1-dichloro-1,2,2,2-tetrafluoroethane - Google Patents

Abstract

PURPOSE:To obtain the title compound in high purity and in high yield, by subjecting 1,2-dichloro-1,2,2,2-tetrafluoroethane to heterogeneous reaction to give 1,1,1-trichloro-2,2,2-trifluoroethane and then fluorinating with hydrofluoric acid. CONSTITUTION:1,2-Dichloro-1,2,2,2-tetrafluoroethane is subjected to heterogeneous reaction in the presence of a heterogeneous catalyst comprising a halide or oxide containing one or more elements preferably selected from Al, Cr, Mg, Ca, Sr, Ba, Fe, Ni and Co to form 1,1,1-trichloro-2,2,2-trifluoroethane, which is then fluorinated with hydrofluoric acid in the presence of a fluorinating catalyst comprising a halide or oxide containing one or more elements selected from Al, Cr, Mg, Ca, Sr, Ba, Fe, Ni, Co, Sb, Nb and Ta to give the title compound in high purity and inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing 1,1-dichloro-1,2,2,2-tetrafluoroethane.

[Prior art and problems] 1.1-dichloro-1,2,2,2-tetrafluoroethyl 7 (R-114a) is produced by the following methods:
．． 2-Trichloro-1,2,2-trifluoroethane (
There is a method of fluorinating haloethane such as Coh FOG IF7). In this case, the reaction product is 1,1-dichloro-1,2,2,2-tetrafluoroethane (R-11
4a) and 1,2-dio-1,1,2,2-tetrafluoroethane (R-114).

This is because during fluorination, the substitution of the fluorine atom in hydrogen fluoride with the chlorine atom in 1.1.2-trichloro-1,2,2-)lifluoroethane (R-113) is not necessarily C
that it does not occur preferentially on the side of ClF2, and that 1,2
-dichloro-1,2,2-tetrafluoroethane (R-114) to 1,1-dichloro-1,2,2
, 2-tetrafluoroethane (R-114a) is considered to be the cause. Among chlorofluorocarbons, there are many isomers with small differences in boiling point, l,1-dichloro-1,2,2゜2-
Tetrafluoroethane (R-114a), 1,2-dichloro-1,1,2,2-tetrafluoroethane (R-1
In 14), the boiling point of both is 3.0°C.

3.8°C, and it is difficult to separate the product. Therefore, currently, high purity products of 1,1-dichloro-1,2,2,2-tetrafluoroethane (R-114a) are available at low cost. It is difficult to obtain.

[Means for Solving the Problems J] The present invention provides highly purified 1,1-dichloro-1,2,2,2
The object of the present invention is to provide a new method for producing -tetrafluoroethane (R-114a).

That is, 1 the present invention involves disproportionation reaction of 1,2-dichloro-1,1,2゜2-tetrafluoroethane (R-114) to form 1,1.1-)lichloro-2.2.2-trifluoroethane (R-114). 1, 1 characterized in that after producing fluoroethane (R-113a), a fluorination reaction with hydrofluoric acid is performed.
-dichloro-1,2,2,2-tetrafluoroethane (
The present invention provides a method for producing R-114a).

Among haloethanes, 1,2-dichloro-1,1, which is sold in large quantities as a refrigerant for coolers,
2,2-tetrafluoroethane (R-114) is the most preferred starting material from an economic point of view. High purity 1
．． In order to produce 1-dichloro-1,2,2,2-tetrafluoroethane (R-114a), 1,2-dichloro-1,1, which is an isomer with very similar boiling points and is also a raw material. 2,2-tetrafluoroethane (R-114
) are all reacted and no by-products are produced in the reaction system 1.
It is necessary to adopt the reaction route. When we investigated the behavior of R-114 in isomerization and disproportionation reactions, we found that the rate of isomerization of R-114 to R-114a was
1,1.1-trichloro-2,2,2-trifluoroethane (R-113a) and 1-chloro-1,1,2,2,
It was found to be less than the rate of disproportionation to 2-pentafluoroethane (R-115). The disproportionation product contains R-
Since 113 was hardly recognized, R-114
By optimizing the catalyst and reaction conditions for the reaction route where R is disproportioned and then fluorinated, high purity R
It was discovered that -114a can be obtained at low cost.

Based on the above study results, the present invention has been made to produce R-114a with high efficiency and high purity using R-114 as a starting material by intensively studying the reaction conditions including a disproportionation catalyst and a fluorination catalyst. This led to the discovery of a manufacturing method. The details of the reaction will be explained below.

In the present invention, the disproportionation catalyst is AI.

A halide or oxide containing at least one element selected from the group consisting of Or, Mg, Ca, Sr, Ba, Fe, Go, and Go can be used. For reasons of acid resistance and activity maintenance, Al2O:+, Cr2O3, MgO, CaO
oxides such as and composite oxides thereof, AlCl3
, CrCl3 and the like are preferably used.

In the present invention, the fluorination catalyst is AI.

Or, Mg, Ca, Sr, Ba, Fe, Ni, Go, S
A halide or oxide containing at least one element selected from the group consisting of Nb, Nb, and Ta can be used. If a gas phase fluorination method is adopted, Al2O3,
Cr2(h.

If a liquid phase fluorination method is used for oxides such as MgO and GaO and their composite oxides.

It is preferable to use halides such as TaF5, NbCl5.5bC15.

All of the above catalysts are preferably activated with hydrogen fluoride, R-11, R-12, halogenated methane, halogenated ethane, etc. containing at least one fluorine atom, before being used in the reaction.

The disproportionation reaction is suitably carried out in the gas phase under normal pressure or pressure, or in the liquid phase under pressure, at a temperature range of 50°C to 550°C, particularly 100°C to 400°C.

The contact time is usually 0.1 to 0.1 when the reaction is carried out in the gas phase.
300 seconds, especially 5 to 30 seconds, and when carried out in a liquid phase, usually 0.1 minutes to 10,000 minutes, particularly preferably,
A residence time in the reactor of about 10 minutes to 1000 minutes is required.

In order to maintain catalytic activity, it is preferable to coexist oxygen or chlorine in an amount of 0.1 to 10% based on R-114.

The fluorination reaction is carried out in the gas phase at normal pressure or under pressure, or in the liquid phase under pressure at 50°C to 550°C, particularly preferably at 50°C.
Suitably, the temperature range is between 450°C and 450°C. The proportions of hydrogen fluoride and R-113a can vary widely. However, one usually uses a stoichiometric amount of hydrogen fluoride to replace the chlorine atoms. Considerably greater than the stoichiometric amount of hydrogen fluoride may be used, for example 4 moles or more, based on the total number of moles of starting materials. The contact time is usually 0.1 to 300 seconds, particularly preferably 5 to 30 seconds, when one reaction is carried out in a gas phase, and usually 0.1 to 300 seconds, particularly preferably 5 to 30 seconds, when one reaction is carried out in a liquid phase.
．． A residence time in the reactor of about 1 minute to 10,000 minutes, particularly preferably about 10 minutes to 1,000 minutes is required.

Similarly to the above, to maintain catalyst activity, oxygen or chlorine is added to R.
-113a is preferably present in an amount of 0.1 to 10%.

The reaction format may be either liquid phase or gas phase, but if a continuous reactor is used, the device can be simplified by unifying the isomerization reaction and fluorination reaction into gas phase reactions. The desired product may be separated by conventional methods, such as fractional distillation. By-produced R-113a, 1,1,2.2
-Tetrachloro-1,2-fluoroethane (R-112
), 1,1,1,2-tetrachloro-2,2-fluoroethane (R-112a), etc. can be recycled to the reaction system.

As described above, the present invention produces highly purified 1,1-dichloro-1°2.2.
A method for producing 2-tetrafluoroethane (R-114a) is provided.

[Example] Examples of the present invention are shown below.

Preparation example 1100gc7) Special grade reagent Al(NO3)3 ・9H2
0,125HNOCR(N03)3.9H20 and 40g of Mg(NO3H.8H20) were dissolved in 2.5 liters of wood, and this and a 28% aqueous solution of ammonium hydroxide 20g were dissolved.
00 g was added to 4 liters of heated water with stirring to obtain a hydroxide precipitate. This was filtered, washed with pure water, and dried, and then calcined at 450° C. for 5 hours to obtain a powdered product. This was molded into a cylindrical shape with a diameter of 5 mm and a height of 5 mm using a tablet molding machine. The catalyst thus obtained was placed in a hydrogen fluoride/nitrogen mixed gas stream before the reaction.
It was activated by fluorination at 200-400°C.

Example 1 Inconel 800 with inner diameter 2.54cv and length loOcm
A U-shaped reaction tube was used as a disproportionation reactor and a fluorination reactor. Two alumina catalysts were activated in the same manner as in the preparation example.
A reaction tube filled with 0.00cc was used as the disproportionation reactor at the first stage, and a reaction tube filled with 2001ml of the fluorination catalyst prepared as shown in the preparation example was used as the fluorination reactor at the second stage for continuous reaction. In the first stage, 1,2-dichloro-1,1,2,2-
Tetrafluoroethane was supplied at 100 ml/sin, chlorine was supplied at 2 ml/sin, and the temperature was maintained at 250°C. Hydrogen fluoride was further supplied to the latter stage at a rate of 50 m1/sin, and 3
It was maintained at 20°C. The gas composition after removing the acid content was analyzed using gas chromatography and l'1F-N)IR. The results are shown in Table 1.

Table 1 Example 2 In the first stage, 10 (lsl/sin) of 1,2-dichloro-1,1,2,2-tetraph)Lt-oloethane was supplied, and chlorine was supplied at 2 ml/sin and maintained at 250°C. , hydrogen fluoride was further supplied to the latter stage at a rate of 25 m1/s+in.
The reaction was carried out under the same conditions as in Example 1 except that the temperature was maintained at °C.

The gas composition was analyzed after acid content was removed. The results are shown in Table 2.

Table 2 Example 3 Contents 20g of aluminum chloride powder, 1,2-dichloro-1,
1,2,2-tetrafluoroethane 6001 was added and held at 80°C for 7 hours. After cooling, the solution was transferred to another Hastelloy C autoclave with a gt liter capacity, and 20 g of antimony pentachloride was added thereto. After raising the temperature to 120° C., hydrogen fluoride was supplied at a rate of 50 g/hr for 4 hours, and the temperature was maintained for an additional 4 hours. The gas composition after removing the acid content was analyzed in the same manner as in Example 1. The results are shown in Table 3.

Table 3 Reference Example 1 Inner diameter 2.54 cm, length loOcm (7) An Inconel 800f MU-shaped reaction tube was used as an isomerization reactor. A reaction tube filled with 2001 alumina catalyst activated in the same manner as in the preparation example was used as an isomerization reactor. l,2-dichloro-1
, 1,2,2-tetrafluoroethane 100i+1/
1 n, chlorine was fed at 21/in and maintained at 250°C. The gas composition was analyzed after acid content was removed. The results are shown in Table 4.

Table 4 [Effects of the Invention] As shown in the Examples, the present invention provides 1,1-dichloro 1,2,2,2-tetrafluoroethane (R-114a), which has been difficult to obtain in high purity. ), 1,2-dichloro-1,1,2,2,-tetrafluoroethane (R-11
It has the effect that it can be produced in high yield using 4) as a starting material.

Claims (1)

[Claims] 1,1,2-dichloro-1,1,2,2-tetrafluoroethane is subjected to a disproportionation reaction to produce 1,1,1-trichloro-2,2,2-trifluoroethane. After generating
1, characterized by carrying out a fluorination reaction with hydrofluoric acid;
A method for producing 1-dichloro-1,2,2,2-tetrafluoroethane. 2. Disproportionation reaction with Al, Cr, Mg, Ca, Sr, Ba
2. The manufacturing method according to claim 1, which is carried out in the presence of a disproportionation catalyst consisting of a halide or oxide containing at least one element selected from the group consisting of , Fe, Ni, and Co. 3. Fluorination reaction with Al, Cr, Mg, Ca, Sr, B
Claim 1, or The manufacturing method according to item 2. 4. According to any one of claims 1 to 3, the disproportionation reaction is carried out in a gas phase under normal pressure or pressure, or under liquid phase pressure in a temperature range of 50 ° C. to 550 ° C. Manufacturing method described. 5. According to any one of claims 1 to 4, the fluorination reaction is carried out in a gas phase under normal pressure or pressure, or under liquid phase pressure in a temperature range of 50°C to 550°C. manufacturing method.