JPH06228022A - Production of 1,1,1,2-tetrafluoroethane - Google Patents

Abstract

PURPOSE:To obtain in high efficiency the subject compound, HFC-134a, as an alternative CFC, which does not deplete the ozone layer. CONSTITUTION:Fluorination of HCFC-133a, which is hard to proceed using conventional fluorinating catalysts, is conducted using a new highly active and selective fluorinating catalyst containing, as essential components, zinc, chromium, oxygen and fluorine elements, 5-50% in the fluorination rate expressed by the formula {Y/(2X+3)}Xl00% (Y is the atom ratio Zn/Cr; X is the atom ratio F/Cr), and 0.01-0.6 in the atomic ratio Zn/Cr.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the production of 1,1,1,2-tetrafluoroethane (hereinafter, abbreviated as HFC-134a), which is an alternative CFC which does not destroy the ozone layer, by using 1-chloro-2,2. , 2-trifluoroethane (hereinafter referred to as HCF
C-133a) and hydrogen fluoride (hereinafter abbreviated as HF) are reacted in the presence of a novel fluorination catalyst to obtain a target compound HFC-134a in high yield.

[0002]

2. Description of the Related Art Halogenated hydrocarbons having 1 to 4 carbon atoms are converted into H
The method of fluorinating with F is roughly classified into a gas phase method and a liquid phase method. Recently, CFCs containing chlorine and bromine in the molecule,
The problem of ozone depletion due to halon has been highlighted, and halogenated hydrocarbons containing hydrogen in the molecule (generally HCF
Fluorinated hydrocarbons (generally abbreviated as HFC) that do not contain chlorine and bromine in the molecule have been proposed, and some have already been mass-produced. As a manufacturing method of these alternative CFCs,
The vapor phase method is particularly effective. In the gas phase method, selection of a catalyst is important, and various catalysts have been proposed so far.

First, as a known fluorination catalyst that has been used in the production of conventional fluorocarbons containing chlorine in the molecule, as described in sulfuric acid and Kogyo, February, 1972, p. 48, Typical examples are chromium oxides and fluorides, and halides such as aluminum and iron. In addition, U.S. Pat. No. 2005707 discloses Cu, Ag, Na, Cd, Ca, Zn supported on an inert carrier.
Halides such as Hg, V, Sb, Mn, Fe, Ni, Co and Pt have been proposed. In addition, by improving the catalyst as described above, chromium oxide is added to Mg, Ca, Sr, Ba, rare earth elements, Th, Ti, Zr, Fe, Co, Ni, C.
A multi-component catalyst containing chromium oxide as a main component (see Japanese Patent Publication No. 49-43922), in which a second component such as u, Zn, Cd, Al, In, Sn, Pb, or Bi is added to improve life and durability. , Amorphous Cr ₂ O ₃ catalyst with improved life and selectivity by the sol-gel method (see Japanese Patent Laid-Open No. 57-119836)
Etc. have been disclosed so far.

[0004]

However, HC containing hydrogen in the molecule proposed as an alternative CFC.
When FC or HFC is produced by reacting a halogenated hydrocarbon with HF, conventional chlorofluorocarbon (CFC) is used.
In most cases, the reaction is difficult to proceed compared to the production of
In particular, HFC-1 by fluorination of HCFC-133a
The synthetic reaction of 34a is a thermodynamically disadvantageous endothermic reaction,
Equilibrium exists. Therefore, in general, HCFC-13
The reaction is performed under the condition that HF of stoichiometry or higher is coexistent with 3a to give a significant equilibrium conversion rate.

[0005] For example, Japanese Patent Laid-Open No. 55-27138
Argues that the reaction is carried out in a molar ratio of HF and HCFC-133a (hereinafter, abbreviated as molar ratio) of 3 or more, preferably in the range of 5 to 12. However, even when the molar ratio is as high as 5 or more, the reaction rate is small when the conventional catalyst is used, and the space velocity is decreased in order to secure an appropriate reaction rate close to the equilibrium conversion rate. It was necessary to take measures such as raising the temperature. That is, the above-mentioned JP-A-5
In Examples 9-12 (Table 3) of 5-27138, CrF
_When a compound obtained by treating 3.3H ₂ O with air is used as a catalyst, the space velocity (hereinafter, abbreviated as SV) is 550 at a molar ratio of 8.
Despite being as low as hr ⁻¹ , a temperature of 400 ° C. or higher is required to obtain an appropriate conversion rate. The selectivity at that time is not so high as 97%.

Japanese Unexamined Patent Publication No. 1-268651 claims that a catalyst containing no Cr can maintain a high level of activity and selectivity, but a catalyst obtained by fluorinating CoCl ₂ / Al ₂ O ₃ of Example 1 In spite of the low SV with a molar ratio of 10 and SV of 120 hr ^-1 , the reaction temperature is 410 ° C, which is higher. The selectivity is bad and is 94% or less. Reducing the SV in this way is not preferable because it leads to a decrease in the production amount per unit catalyst. Further, an increase in the reaction temperature causes not only a loss of thermal energy but also a decrease in the selectivity. Further, according to the findings of the present inventors, the catalyst life is shortened.

The fluorination reaction of a halogenated hydrocarbon containing hydrogen in the molecule has an extremely short catalyst life as compared with the fluorination reaction of a raw material containing no hydrogen (JP-A-1-262946).
Therefore, this effect is serious in the fluorination reaction of HCFC-133a. A method of adding oxygen to the raw material gas to prolong the life of the catalyst (Japanese Patent Laid-Open No. 55-2713).
9 and Japanese Unexamined Patent Publication No. 1-272535) have been proposed, but in the study by the present inventor, the life prolonging effect was not recognized so much.
Disadvantages such as increased by-products were recognized. Therefore,
From the viewpoint of not only expanding the production volume but also extending the life of the catalyst, it has higher activity than conventional fluorination catalysts.
There is a strong demand for catalysts with high selectivity.

Recently, in the specification of EP 449614, hydrogen-containing halogenated hydrocarbons, trichlorethylene, H
Chromia and zinc- or nickel-promoted chromia are described as preferred catalysts for the fluorination reaction of CFC-133a, but the composition of the catalyst and the promoting effect of Zn or Ni are completely unknown. In the patents disclosed so far, there is an example of fluorinating a halogenated hydrocarbon with HF using an oxide or a fluoride containing Zn and Cr or Ni and Cr as a catalyst. For example, the above-mentioned Japanese Patent Publication Sho-49-
In Table 1 of 43922, CF ₂ ClCFCl ₂ (hereinafter,
Cr ₂ O ₃ catalyst containing Zn in the fluorination reaction of CFC-113 (the addition amount of Zn is ZnO and Cr ₂ O ₃
10:90 by weight ratio of Cr ₂ O ₃ without addition of Zn
The CFC-113 conversion rate and 115 selectivity were slightly improved as compared with the catalyst, and the CFC was increased in the Cr ₂ O ₃ catalyst containing Ni (the addition amount of Ni was 10:90 by weight ratio of NiO and Cr ₂ O ₃ ).
Although the improvement in -113 conversion was small, the 115 selectivity, which is an index of the fluorination ability, increased considerably.

However, the activity accelerating effect remains in a small range as compared with Mg, Al, Sr and the like shown in other examples. Further, Japanese Patent Publication No. 54-34712 discloses a fluorination reaction of CFC-113 with a catalyst in which small amounts of compounds of Zn, Cr, Ni and Fe are added to aluminum fluoride, and in Table 1 of this patent, When a Zn compound is further added to a catalyst obtained by adding Cr and Ni compounds to aluminum fluoride, the conversion rate of CFC-113 is considerably reduced, but the symmetric compound (CFC-
It is shown that the selectivity of 114) is greatly improved.

Further, EP502605 discloses that a Cr-based catalyst added with an active-promoting amount of Zn provides high activity. However, the amount of Zn added is not clearly defined, and the contents of O and F are not mentioned. According to the study by the present inventors, high activity cannot be obtained by simply adding Zn to a Cr-based catalyst, and a specific fluorination ratio and Zn / Cr ratio (Cr
It was revealed that the activity is enhanced only in the atomic ratio of Zn to atoms. That is, when the elements of Zn, Cr, O, and F as specified in the present invention coexist at a specific composition ratio, the activity is dramatically increased and the selectivity is also improved. The present invention has been made based on the above invention and is an alternative CFC that does not destroy the ozone layer, HFC-134a.
It aims at providing the method of manufacturing efficiently.

[0011]

In the present invention, HC
By the reaction of FC-133a and HF, HFC-134
In the method for producing a, the solution was to use a fluorination catalyst containing elements of Zn, Cr, O, and F as essential components and having a composition ratio of the constituent components within a specific range. That is, the value of the fluorination rate represented by the formula {Y / (2X + 3)} × 100% is 5 to 50%, preferably 7 to
In the range of 40%, the atomic ratio of Zn to Cr is 0.
It is a specific composition ratio of 01 to 0.6, particularly preferably 0.03 to 0.5. However, in the formula, X represents the atomic ratio of zinc to chromium contained in the catalyst, and Y represents the atomic ratio of fluorine to chromium.

Z contained in the fluorination catalyst used in the present invention
The substantial atomic valences of n and Cr are divalent and trivalent, respectively. Therefore, the above formula represents the ratio of the amount of F bound to Zn and / or Cr to the maximum amount of F (which is 100%) that can bind to Zn and / or Cr, and The ratio of F in the inside, and thus the ratio of O are given.

It is not so preferable that a large amount of alkali metal is contained as a constituent component of the catalyst (% order by weight), but other elements (excluding Zn, Cr, O and F) may be contained in the% order or more. However, when a fluoride of a metal other than Zn and Cr is contained in the atomic ratio of Cr to the order of% or more, F bonded to a metal other than Zn and Cr is used.
It is necessary to exclude this and calculate the fluorination rate because it will be large. That is, a compound containing Zn and Cr as a metal component (hereinafter Zn /
The range of the fluorination ratio of Cr compounds (abbreviated as Cr compound) must be discussed. As an example, the Zn / Cr compound is
It is also possible to support on activated carbon, aluminum fluoride, calcium fluoride, etc., which are stable catalyst carriers even in an F gas flow. However, when a fluoride is used as the carrier, fluorine derived from the fluoride carrier is used as the fluorine content. The fluorination rate must be determined by subtracting the amount.

The catalyst or Zn / Cr compound used in the present invention is a halogenated hydrocarbon having HF or F ₂ and fluorine in the molecule, which is obtained by using an oxide or hydroxide containing Zn and Cr as a catalyst precursor. Fluorination with O, etc., and partially replacing O or OH with fluorine. Fluoride containing Zn and Cr is used as a catalyst precursor, and this is partially oxidized with oxygen-containing gas such as air and water. Method of replacing with O or OH, halogen bonded to Zn and / or Cr (F
Groups other than O or OH such as nitric acid, sulfuric acid, carbonic acid, acetic acid, and formic acid (the groups referred to here are not only electrically neutral atomic groups but also atomic groups having a positive or negative charge). (In particular, it is often an anion) and a compound containing O and / or OH as a catalyst precursor, which is fluorinated with HF, F ₂ , or a halogenated hydrocarbon having fluorine in the molecule, It can be prepared by a method of substituting fluorine for a group other than O and / or OH.

Therefore, in the catalyst of the present invention containing Zn, Cr, O and F as essential components, the groups bonded to Zn and / or Cr are substantially three kinds of groups F, O and OH.
Since the proportion of H in the molecular weight of OH is small, Zn /
The components other than Zn, Cr, and F constituting the Cr compound may be considered to be zero in calculation. The fluorine content can be controlled by further fluorinating or oxidizing the catalyst obtained by the above method. A preferred method is a method of fluorinating a hydroxide or an oxide as a catalyst precursor, which can replace a hydroxyl group or oxygen with fluorine under relatively mild conditions, and the fluorine content can be easily controlled. Is.

As the method for preparing the catalyst precursor, any of conventionally known methods such as kneading method, impregnation method and coprecipitation method can be used, and as a raw material for preparing the catalyst precursor, industrial scale is used. Any compound may be used as long as it is available at. Of the above methods, the impregnation method and coprecipitation method are Z
It is preferable because n and Cr can be uniformly distributed. Among them, the coprecipitation method is more preferable because it is possible to uniformly adjust the bulk composition of the catalyst. Therefore, as an example of a preferable method for preparing a catalyst precursor, a method in which a precipitation agent is added to a liquid in which a compound of Zn and Cr is dissolved to form a precipitate, which is filtered, washed, dried, and calcined (example of coprecipitation method) , Cr ₂
Examples thereof include a method of impregnating O ₃ or chromium hydroxide with a solution of a Zn compound, followed by drying and firing (an example of the impregnation method). As an example of a more preferable preparation method, Zn in the coprecipitation method is used.
While controlling the pH of the reaction solution to be in the range of 6 to 12, particularly preferably 6.5 to 10, the solution in which the Cr compound is dissolved and the precipitant are added dropwise at the same time or alternately. Examples of the method include filtering, washing, drying and firing the prepared slurry.

When a molded product is desired as the catalyst shape, it can be molded by tableting before or after firing, or by extrusion molding before drying. If a supported type catalyst is desired, it can be prepared, for example, by impregnating a solution in which a compound of Zn and Cr is dissolved into activated carbon, aluminum fluoride, alumina, etc., drying and firing, and then fluorinating with HF. it can.
Even if alumina is used as a carrier, alumina is substantially converted to aluminum fluoride when fluorinated at a temperature of about 350 ° C.

The catalyst may be prepared by the above-mentioned method or any other known method, but the composition ratio of Zn, Cr, O and F, which are the constituent components of the catalyst, must be within the above-specified range. That is, the value of the fluorination ratio giving the ratio of F and O is in the range of 5 to 50%, preferably 7 to 40%, and the atomic ratio of Zn to Cr is 0.01 to.
The specific range is 0.6, preferably 0.03 to 0.5, particularly preferably 0.05 to 0.5. If the fluorination rate or the Zn / Cr ratio deviates from the above range, the contents of the essential components Zn, Cr, O, and F deviate from the appropriate ranges, so that good catalytic activity and selectivity cannot be obtained.

The Zn / Cr ratio can be easily adjusted by controlling the ratio of the powder to be mixed in the kneading method and the solution concentration and the composition of the Zn and / or Cr compound in the impregnation method or the coprecipitation method. It On the other hand, the contents of F and O are achieved by selecting the processing conditions according to the physical properties of the catalyst precursor. That is, in the case where the catalyst precursor is a compound containing a metal oxide or hydroxide, a group that can be substituted with oxygen and fluorine other than oxygen, select fluorination conditions depending on the fluorination easiness of the compound, When oxidizing a metal fluoride, it is important to select an oxidation condition according to the easiness of oxidation of the fluoride.

Since the fluorination ratio can be easily adjusted to an appropriate value under mild conditions, an example of a preferable catalyst preparation method is a dried product (hydroxide) obtained by the coprecipitation method. It is considered that) is calcined in an inert or substantially reducing atmosphere, and further fluorinated with HF at 300 to 450 ° C., preferably under pressure ( ^{2 to} 10 kg / cm ² ). In the coprecipitation method, the solution of Zn and Cr compounds and the precipitant were mixed to adjust the pH of the reaction solution.
Is controlled to fall within the range of 6 to 12, particularly preferably 6.5 to 10, while the slurry prepared by dropping both at the same time or alternately is filtered, washed, and dried. If you use the method of baking and fluorinating,
This is a particularly preferred method because the fluorination ratio can be more easily optimized. The Zn / Cr ratio and fluorination rate of the catalyst can be calculated from the contents of Zn, Cr, O and F obtained by chemical analysis.

The fluorination catalyst of the present invention containing Zn, Cr, O and F elements as essential components and having a composition ratio of constituent elements within a specific range is applied when fluorinating a halogenated hydrocarbon with HF. it can. Among them, the conventional fluorination catalyst is particularly effective for the fluorination reaction of HCFC-133a, which has a very low reaction rate. That is, since the conversion rate of HCFC-133a is high and the selectivity to HFC-134a is high as compared with the case of using a conventional fluorination catalyst, the target compound HFC-134a can be obtained in high yield. Not only that, a certain yield can be obtained at a low reaction temperature, and as a result, a longer catalyst life can be achieved. The fluorination reaction of HCFC-133a can be carried out by a reaction method such as a fixed bed, a fluidized bed or a moving bed, but a fixed bed is generally used. The reaction conditions are JP-A-53-10540.
No. 4 and JP-A-55-27138. That is, molar ratio: 3 to 20, temperature:
300 to 400 ° C, pressure: atmospheric pressure to 20 kg / cm ²
(Gauge pressure), SV: 100 to 10,000 hr ⁻¹ . However, since the activity of the fluorination catalyst according to the present invention is higher than that of the conventional fluorination catalyst, the preferable temperature and SV are 300 to 350 ° C. and 750 to 500, respectively.
It will be in the range of ⁰ hr ^-1 .

[0022]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but it goes without saying that the present invention is not limited by such description. In the explanation, Zn / Cr
Ratio, F / Cr ratio, Al / Cr ratio, F / Al ratio, Mg / C
The r ratio represents the atomic ratio of each element contained in the catalyst obtained from the chemical analysis, and the molar ratio in the reaction example represents the molar ratio of HF to HCFC-133a. SV is a value converted into a standard state, and pressure is a gauge pressure.

Preparation Example 1 Cr (NO ₃ ) ₃ · was added to a 10-liter container containing 1 liter of pure water.
9H ₂ O1257g and _{Zn (NO 3) 2 · 6H} 2 O18
While stirring a solution prepared by dissolving 7 g in 3 l of pure water and 1.1 l of 28% by weight ammonia water, the pH of the reaction solution was 8.5.
It was added dropwise over about 2 hours while controlling so as to fall within the range of ˜9.5. The obtained hydroxide slurry was filtered, washed well with pure water, and then dried at 120 ° C. The obtained solid was ground, mixed with graphite, and pelletized by a tablet molding machine. The pellets were heated at 400 ° C. under N ₂ flow for 4 times.
It was calcined for a period of time to obtain a catalyst precursor.

60 ml of the catalyst precursor was filled in a reaction tube made of Inconel, and it was diluted with N _{2 at} normal pressure under an HF gas flow of 400.
40 ° C., followed by 100% HF flow without dilution with N ₂
Fluorination treatment was performed at 0 ° C. The composition of the pellets after the treatment is shown below. Zn: 11.8 wt% Cr: 52.5 wt% O: 23.2 wt% F: 9.5 wt% From these values, the Zn / Cr ratio was 0.18 and the fluorination ratio was 15%. .

Comparative Preparative Example 1 Inconel reaction tube was filled with 60 ml of the catalyst precursor prepared in the same manner as in Preparative Example 1, and HF was diluted with N _{2 at} atmospheric pressure.
100% H at 300 ° C under a stream of air, followed by N ₂ dilution
The fluorination treatment was performed at 300 ° C. in an F gas stream. The composition of the pellets after the treatment is shown below. Zn: 12.8 wt% Cr: 55.2 wt% O: 27.7 wt% F: 2.0 wt% From these values, the Zn / Cr ratio was 0.18 and the fluorination ratio was 3%. .

Comparative Preparative Example 2 Inconel reaction tube was filled with 60 ml of the catalyst precursor prepared in the same manner as in Preparative Example 1, and HF was diluted with N _{2 at} atmospheric pressure.
100% H at 600 ° C under a stream of air, followed by N ₂ dilution
The fluorination treatment was carried out at 600 ° C. in an F 2 stream. The composition of the pellets after the treatment is shown below. Zn: 10.2 wt% Cr: 45.0 wt% O: 10.5 wt% F: 30.4 wt% From these values, the Zn / Cr ratio was 0.18 and the fluorination ratio was 55%. .

Comparative Preparation Example 3 A Zn-free catalyst precursor was prepared in the same manner as in Preparation Example 1 except that Zn (NO ₃ ) ₂ .6H ₂ O was not added. 60 ml of this catalyst precursor was filled in a reaction tube made of Inconel and 400 ° C. under an HF stream diluted with N _{2 at} normal pressure.
Then, 400% under 100% HF gas flow without N ₂ dilution
Fluorination treatment was performed at ° C. The composition of the pellets after the treatment is shown below. Cr: 59.6 wt% O: 20.6 wt% F:
30.4% by weight From these values, the Zn / Cr ratio is 0 and the fluorination ratio is 25%.
Met.

Comparative Preparation Example 4 Al (NO ₃ ) instead of Zn (NO ₃ ) ₂ .6H ₂ O
Except the addition of ₃ · 9H ₂ O196g in the same manner as in Preparation Example 1 to prepare a catalyst precursor containing Al / Cr. The catalyst precursor 60ml was packed into an Inconel reaction tube, with HF stream under 400 ° C. was N ₂ diluted in normal pressure, followed by fluorination at 100% HF gas stream under 400 ° C. without N ₂ dilution was carried out. The composition of the pellets after the treatment is shown below. Al: 4.3 wt% Cr: 52.0 wt% O: 18.7 wt% F: 21.8 wt% From these values, the Al / Cr ratio was 0.16.

Preparation Example 2 100 g of high-purity alumina was immersed in a solution prepared by dissolving 111 g of CrCl ₃ .6H ₂ O and 6 g of ZnCl ₂ in 80 ml of pure water to absorb the entire amount. This was dried at 120 ° C., calcined at 400 ° C. for 3 hours in an air stream, and further heated in an H ₂ stream at 350 ° C.
It was calcined at ℃ for 3 hours to obtain a catalyst precursor. Catalyst precursor 60m
filled with l to Inconel reaction tube, with N ₂ diluted HF gas stream under 380 ° C., followed by no N ₂ dilution of 100% HF
The fluorination treatment was performed at 380 ° C. in an air stream. The composition of the supported catalyst after the treatment is shown below. Zn: 1.4 wt% Cr: 10.8 wt% Al:
26.9% by weight O: 6.6% by weight F: 53.6% by weight

Therefore, the Zn / Cr ratio is 0.10, F / C
The r ratio was 13.6 and the Al / Cr ratio was 4.8. Further, when the alumina used as the carrier was fluorinated under the same conditions as the catalyst precursor, the composition of the treated aluminum fluoride had the following values. Al: 33.8 wt% O: 4.0 wt% F:
61.8% by weight Therefore, the F / Al ratio is 2.6, and the F / Cr ratio excluding the fluorine derived from the aluminum fluoride of the carrier is 0.
88 (= 13.6-2.6 × 4.8), Zn and Cr
The fluorination ratio of the compound containing was 35%.

Comparative Preparation Example 5 A catalyst precursor was prepared in the same manner as in Preparation Example 2 except that ZnCl ₂ was not added to the metal solution, and then fluorination treatment was performed. The composition of the supported catalyst after the treatment is shown below.
Cr: 11.0% by weight Al: 27.4% by weight O: 6.4% by weight F: 54.7% by weight From these values, the Zn / Cr ratio was 0. The fluorination ratio of the Cr-containing compound obtained by excluding the fluorine derived from aluminum fluoride is 37.
%Met.

Comparative Preparation Example 6 MgC instead of ZnCl ₂
l ₂ · 6H except the ₂ O8g be added to the metal solution catalyst precursor was prepared in the same manner as in Preparation Example 2, further subjected to fluorination treatment. The composition of the supported catalyst after the treatment is shown below. Mg: 0.5 wt% Cr: 10.9 wt% Al: 2
7.2 wt% O: 7.0 wt% F: 53.4 wt% From these values, the Mg / Cr ratio was 0.10.

Example 1 50 ml of the catalyst prepared in Preparation Example 1 was filled in an Inconel reaction tube, and HCFC-13 was prepared by HF under the following reaction conditions.
The fluorination reaction of 3a was performed. The outlet gas of the reaction tube was blown into an alkali trap to remove unreacted HF and generated HCl, and the gas composition was analyzed by gas chromatography.
The results are shown in Table 1. Temperature: 320 ° C., pressure: 2 kg / cm ² , molar ratio: 8,
SV: 1500 hr ^-1

Comparative Example 1 HCFC-133a was subjected to a fluorination reaction under the same conditions as in Example 1 using the catalyst prepared in Comparative Preparation Example 1 having a low fluorination rate. The results are shown in Table 1.

Comparative Example 2 HCFC-133a was fluorinated under the same conditions as in Example 1 except that the catalyst prepared in Comparative Preparation Example 2 having a high fluorination ratio was used. The results are shown in Table 1.

Comparative Example 3 HCFC-133a was fluorinated under the same conditions as in Example 1 except that the catalyst prepared in Comparative Preparation Example 3 containing no Zn was used. The results are shown in Table 1.

COMPARATIVE EXAMPLE 4 HCFC-133a was prepared under the same conditions as in Example 1 except that the catalyst prepared in Comparative Preparation Example 4 in which Al was added instead of Zn was used.
Was fluorinated. The results are shown in Table 1.

[0038]

[Table 1]

In the table, the yield of 134a and the selectivity of 134a represent the yield of HFC-134a and the selectivity of HFC-134a, respectively.

From the results shown in Table 1, high activity and selectivity are obtained only when the elemental composition ratio of Zn, Cr, O, and F is within a specific range, and the activity is high when a metal other than Zn (Al) is added. Can be seen to decrease.

Example 2 Using the catalyst prepared in Preparation Example 2 under the following conditions, HCFC
A fluorination reaction of -133a was performed with HF. The results are shown in Table 2. Temperature: 330 ° C., pressure: normal pressure, molar ratio:
8, SV: 2500 hr ^-1

Comparative Example 5 HCFC-133a was fluorinated under the same conditions as in Example 2 except that the catalyst prepared in Comparative Preparation Example 5 containing no Zn was used. The results are shown in Table 2.

Comparative Example 6 HCFC-133a was prepared under the same conditions as in Example 2, except that the catalyst prepared in Comparative Preparation Example 6 was prepared by adding Mg in place of Zn.
Was fluorinated. The results are shown in Table 2.

[0044]

[Table 2]

From the results shown in Table 2, it can be seen that also in the supported type catalyst, the catalyst having the composition ratio of the elements of Zn, Cr, O and F in the specific range has high activity and selectivity.

[0046]

As described above, HFC-134a can be obtained in a high yield by carrying out the fluorination reaction of HCFC-133a with HF using the fluorination catalyst according to the present invention, and further, the catalyst life Can be extended.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Tetsuo Nakajo, Tetsuo Nakajo 5-1 Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Denko K.K. Chemicals Research Laboratory (72) Hidetoshi Nakayama 5-1-1, Ogimachi, Kawasaki-ku, Kawasaki-shi, Kanagawa No. Showa Denko Chemicals Laboratory

Claims (2)

[Claims] 1. An element including zinc, chromium, oxygen and fluorine as an essential component, {Y / (2X + 3)} × 100%
In the presence of a fluorination catalyst having a fluorination ratio represented by the formula of 5 to 50% and an atomic ratio of zinc to chromium of 0.01 to 0.6, hydrogen fluoride is added in a gas phase. A method for producing 1,1,1,2-tetrafluoroethane, which comprises reacting 1-chloro-2,2,2-trifluoroethane. (In the formula, X represents the atomic ratio of zinc to chromium contained in the catalyst, and Y represents the atomic ratio of fluorine to chromium.) 2. The method according to claim 1, wherein a fluorination catalyst having a fluorination ratio in the range of 7 to 40% is used.