KR100377125B1 - Chromium-based fluorination catalyst, production method thereof, and fluorination method - Google Patents

Abstract

In order to produce high-productivity hydrocarbon fluoride, and to provide a catalyst and a method for preparing the catalyst for the purpose, the essential constituents are Cr, Ga, 0 and F, and the Ga / Cr atomic ratio is 0.001-0.15. Provided are chromium-based fluorination catalysts. Catalysts are prepared, in particular, by fluorination of precursors of oxides or hydroxides. HF and halogenated hydrocarbons are contacted in the gas phase in the presence of this catalyst.

Description

CHROMIUM-BASED FLUORINATION CATALYST, PRODUCTION METHOD THEREOF, AND FLUORINATION METHOD

Hydrocarbon fluoride (hereinafter referred to as "HFC") that does not contain chlorine and thus does not destroy the ozone layer, among others, difluoromethane (hereinafter referred to as "HFC-32"), 1,1,1,2 When preparing tetrafluoroethane (hereinafter referred to as "HFC-143a") and pentafluoroethane (hereinafter referred to as "HFC-125"), the present invention is improved to produce HFC with high productivity. A fluorinated catalyst, a method for producing a fluorinated catalyst, and a method for effectively producing HFC by contacting hydrogen fluoride and a halogenated hydrocarbon in a gas phase using the catalyst.

Typical examples of the industrial production of HFCs are contacting hydrogen-containing halogenated hydrocarbons with HF (in many cases, the addition of HF with unsaturated halogenated hydrocarbons as starting material and the exchange reaction of halogens other than F and F are carried out simultaneously). It is a method of substituting halogen other than F by F. However, the reaction does not proceed smoothly in most cases, and the production of HFC is highly dependent on the catalyst used.

An example of the most difficult reaction is the synthesis of HFC-134a by fluorination of 1-chloro-2,2,2-trifluoroethane (hereinafter referred to as "HFC-133a"), which reaction is clearly thermodynamically useful. It is not endothermic reaction. Thus, the reaction is generally performed at relatively high temperatures by co-existing HF with HFC-134a in an amount above the stoichiometric amount. According to Japanese Unexamined Patent Publication (Kokai) No. 55-27138, for example, HFC-134a is a catalyst, and the reaction is carried out at a temperature of 400 ° C using a compound obtained by treating CrF ₃ .3H ₂ O as air. This yields a yield of 32%. At these high reaction temperatures the reaction promotes coking of the catalyst and reduces catalyst life. In order to prevent coking, a study of coexisting oxygen in the reaction gas (Japanese Unexamined Patent Publication (Kokai) No. 55-27139) has been performed, but this method is not preferable because of the increase in chlorine byproducts. In order to limit the formation of chlorine byproducts, Japanese Patent Application Publication No. 5-88690 discloses the reaction in the presence of oxygen using a catalyst obtained by fluorinating CoC1 ₂ / Al ₂ 0 ₃ which is not based on Cr. Process is disclosed, but the catalyst has low activity and low productivity. For these reasons, tests have been conducted so far to sustain the life of the catalyst. In other words, Japanese Unexamined Patent Publication (Kokai) No. 2-172933 contains at least one component selected from Al, Mg, Ca, Ba, Sr, Fe, Ni, Co, and Mn, and also contains Cr. It is clarified that catalysts consisting of halides or oxides have high durability (long life). EP 502605 discloses a Zn supported Cr-based catalyst. In addition, Japanese Unexamined Patent Publication (Kokai) No. 4-34694 discloses a catalyst consisting of Cr ₂ O ₃ partially fluorinated and carrying Ru and Pt, and Japanese Unexamined Patent Publication (Kokai) No. 5-269382 The patent discloses a catalyst having a long lifetime, the catalyst consisting mainly of chromium oxide and nickel oxide.

However, caulking for catalysts is active in the fluorination reaction of hydrogen-containing halogenated hydrocarbons as a method for producing HFCs, and even the catalysts described above do not have sufficient lifetimes. In other words, it has been necessary in the past to select reaction conditions in which caulking is difficult to occur. Since the progress of caulking is small when the ratio of the HF feed amount (hereinafter referred to as "molar ratio") with respect to the supply amount of organic substance is small, the progress of coking is delayed by increasing this molar ratio when a conventional fluorination catalyst is used. However, an increase in the molar ratio means a decrease in the supply of organic material (when SV remains constant) and a drop in STY (space time yield). It can thus be concluded that the catalyst life continues in accordance with the prior art at the expense of STY to a certain extent.

Thus, if coking occurs more difficult than conventional catalysts and a catalyst with a longer lifetime can be obtained, not only can the catalyst last longer but also the reaction can be carried out at a lower molar ratio, resulting in improved productivity. Can be.

In view of the background described above, the present invention effectively produces HFCs by contacting HF in the gas phase with a fluorinated catalyst having a long lifetime in the production of HFCs, and halogenated hydrocarbons having 1-4 carbon atoms by using the catalysts described above. The purpose is to provide a way to.

The inventors of the present invention intensively conducted their studies to solve the problems described above, containing Ga, Cr, 0 and F as essential components, and the atomic ratio of Ga to Cr is 0.0001-0.15, preferably 0.001-0.1 And particularly preferably 0.003-0.05 have been found to have significantly longer lifetimes than conventional Cr-based fluorine catalysts. Thus, the present invention has been completed.

Thus, the present invention provides:

(1) a catalyst containing Ga, Cr, 0 and F as essential catalyst components and having an atomic ratio of Ga to Cr of 0.0001-0.15, preferably 0.001-0.1 and particularly preferably 0.003-0.05;

(2) A method for producing a catalyst (1) comprising contacting a fluorine, hydrogen fluoride or fluorine-containing hydrocarbon with a catalyst precursor containing a Cr component and a Ga component and carrying out a fluorination treatment; And

(3) A method of fluorinating a halogenated hydrocarbon, comprising contacting the halogenated hydrocarbon with HF in the presence of a catalyst (1).

Although the chromium-based fluorination catalyst according to the present invention does not have a much higher preference (in% by weight) of alkali metals in addition to Ga, Cr, 0 and F as constituents, the catalyst contains other components in% order. can do. In particular, at least one kind of component selected from groups 8, 9, 10, 11 and 12 (new IUPAC nomenclature), which are expected to provide activity promoting effects as accelerators or cocatalysts, among others Co, Ni, Cu, Zn , Cd and the like may be contained in an atomic ratio of Cr to 0.001-0.5 and preferably 0.003-0.2.

The catalyst according to the invention uses compounds containing Ga and Cr (eg oxides and hydroxides) as catalyst precursors, and the catalyst precursor is fluorinated by halogenated hydrocarbons containing fluorine in HF, F ₂ or its molecules, and thus It can be prepared by substituting 0 and OH in part by fluorine. Compounds containing Ga and Cr may be supported on the carrier, examples of suitable carriers include activated carbon, alumina, aluminum fluoride, magnesium fluoride, and the like.

Known methods such as kneading, impregnation, coprecipitation and the like can be used as the method for preparing the catalyst precursor, and any material can be used as a starting material for preparing the catalyst precursor as long as they can be used on an industrial scale. Among the methods described above, the impregnation method and the coprecipitation method are preferable because they can introduce Ga and Cr into the high dispersion. Among other things, coprecipitation is more preferable because this method can algebraically control the dispersion state of Ga. Thus, an example of a preferred method of preparing a catalyst precursor is a step of reacting a solution of salts of Ga and Cr with a precipitant to form a precipitate, and performing filtration, washing, drying and burning of the precipitate (an example of coprecipitation method). ), Or impregnating chromium oxide or chromium hydroxide with a solution of a Ga compound, and carrying out drying and combustion (example of impregnation method). When using a carrier, a catalyst precursor can be prepared by impregnating the carrier with a solution in which Ga and Cr compounds are dissolved, and performing drying and combustion.

An example of a more preferred method of preparing a catalyst precursor is to pre-add a precipitant (alkali) to a slurry of hydroxide hydroxide (especially tertiary hydroxide) in an amount sufficient to neutralize the Ga and Cr salts to be added at least later, followed by The method consists of slowly adding the mixed solution and carrying out the separation, washing, drying and burning of the obtained product, and a solution in which the Ga and Cr salts and the precipitant are dissolved dropwise simultaneously or alternately dropwise to form a slurry, while the reaction solution The reaction solution is adjusted to have a pH of 6-12 and particularly preferably 6.5-10, followed by filtration, washing, drying and combustion of the reaction product.

Nitrates, chlorides and sulfates of Ga and Cr compounds can be suitably used as starting materials for the preparation of catalyst precursors. Among them, nitrate and chloride are particularly preferred for the coprecipitation method and the impregnation method, respectively. Preferred examples of precipitants are ammonia, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium hydroxide, potassium carbonate, potassium hydrogencarbonate, ammonium carbonate and ammonium hydrogencarbonate. Especially preferred among them is ammonia.

When molding is required in the form of a catalyst, tablet-forming is carried out before or after the combustion described above, or extrusion is carried out before drying.

Preferably drying is carried out in an atmosphere of air or an inert gas such as N ₂ for at least 30 minutes at a temperature of 80-130 ° C., in particular 90-120 ° C., but other drying methods such as vacuum drying can also be carried out.

The combustion is carried out at a temperature of 300-600 ° C., preferably 350-500 ° C., but the combustion atmosphere should be selected according to the production method used. In other words, when a chromium compound such as chromium hydroxide, chromium oxide, or the like is contacted with O ₂ at a high temperature of about 350 ° C. or more, a significant drop in specific surface area occurs, and in the case of activated carbon, it is burned and extinguished. Thus, when a chromium compound is used as the main component of the catalyst precursor without using a carrier or when activated carbon is used as the carrier, it is exposed to an atmosphere containing O ₂ at 1.000 Pa (absolute pressure) at a temperature other than 350 ° C. Combustion is preferably carried out in an inert gas such as N ₂ , Ar, or the like, or a reducing gas atmosphere. As used herein, "reduced gas atmosphere" means an atmosphere containing a gas having a reducing powder such as H ₂ , CO, NO, and the like, and may include other inert gas and moisture. An oxidizing gas such as O ₂ may be contained at a concentration that does not pose any stability problem, but is preferably not contained.

When alumina or various metal fluorides are used as the carrier, combustion can be carried out in an O ₂ -containing atmosphere, typically air, since the carrier provides the effect of preventing the drop of specific surface area even in an O ₂ atmosphere. However, as described in Japanese Unexamined Patent Publication (Kokai) No. 5-92141, a problem arises in that Cr is dispersed upon fluorination of the precursor carried out after combustion. Thus, when using the carrier described above, combustion is also carried out in an inert gas or reducing gas atmosphere. Separately, once the combustion is carried out in an inert gas, it is preferably further carried out in a reducing gas atmosphere.

More preferred method is a method of treating the heat treatment step under a reducing gas atmosphere in the sintering process. In other words, when the chromium compound is used as the main component of the catalyst precursor or when activated carbon is used as the carrier, combustion is carried out immediately after the drying step in a reducing gas atmosphere. Separately, it is preferable to carry out the combustion once in an inert gas and then further in a reducing gas atmosphere. When using alumina and various metal fluorides as carriers, it is preferred to carry out directly in a reducing gas atmosphere after the drying step, or to carry out the combustion once in an O ₂ -containing atmosphere and then further in a reducing gas atmosphere.

When the heat treatment is carried out in the reducing gas atmosphere described above, the amount of Cr dispersion upon fluorination of the catalyst precursor before the reaction can be reduced, and the catalytic activity can be increased. In addition, other effects can be expected. The heat treatment temperature is suitable 350-500 ° C, preferably 370-460 ° C, most preferably 370-450 ° C. The kind of reducing gas used is H ₂ , CO, NO, and the like, but H ₂ is easy to handle and can be appropriately used. The concentration of reducing gas is 0.1-100% by volume and can coexist in the gas at any time if 20% by volume or less of water or 99.9% by volume of inert gas is required. However, the O ₂ concentration should be limited to 0.1 vol% or less in terms of stability. The gas flow rate is suitable for 10-1,000 h ⁻¹ by GHSV (converted to standard state), and a pressure of 10 kg / cm ² at atmospheric pressure is easy to handle. The heat treatment time is at least 30 minutes and preferably 1-10 hours.

It is not desirable to expose the catalyst precursor heat treated in a reducing gas atmosphere to an atmosphere having an O ₂ pressure of at least 1,000 Pa at high temperature and absolute pressure. Therefore, after the precursor is burned in a reducing gas atmosphere, it is not further burned in an O ₂ containing atmosphere such as air. In addition, when replacing the atmosphere in the system with air upon removal of the precursor after completion of combustion in a reducing gas atmosphere, the operation of introducing O ₂ into the reaction system at a temperature of 200 ° C. or higher should be avoided. In other words, to gradually increase the O ₂ concentration in the system, the pressure must be relaxed to atmospheric pressure by introducing air gradually into the system, preferably at 150 ° C and more preferably at 120 ° C or less.

The preparation of the catalyst precursor can be carried out by the method described above or by a previously known method, but the atomic ratio of Ga to Cr (hereinafter referred to as "Ga / Cr ratio") is preferably 0.0001-0.15, preferably Preferably 0.001-0.1 and particularly preferably 0.003-0.05. If the Ga / Cr ratio is below the range described above, the anti-caulking effect cannot be obtained and if the Ga / Cr ratio is too large, the reaction rate drops undesirably. The Ga / Cr ratio can be easily adjusted by adjusting the proportion of the powder to be mixed in the case of kneading method and by adjusting the concentration of the Ga and / or Cr compound solution and the composition of the solution in the case of the impregnation method and the coprecipitation method.

The fluorination catalyst according to the invention also requires 0 and F as essential components. Suitable ranges of 0 and F contents vary depending on the Ga / Cr ratio and the preparation method of the catalyst precursor, but based on the total weight of the catalyst, at least 0.3% by weight is required for each component. The preferred range of zero content is 1-25% by weight, and the preferred F content is 15-45% by weight. In order for the catalyst to contain 0 and F, the compounds containing Ga and Cr are fluorinated by the gas of HF, F ₂ or halogenated hydrocarbons containing F in their molecules, as already described. Among them, the fluoridation method using HF is excellent in terms of security.

The fluorination temperature of the catalyst precursor before the reaction is 300-500 ° C. and particularly preferably 300-450 ° C. The concentration of the fluorinating agent, such as HF, may be 0.1-100% by volume, but the fluorinating agent is preferably diluted with an inert gas such as N ₂ whenever necessary, and consequently the temperature rise due to exotherm (hereinafter “ΔT”). At most 50 ° C.). Suitable gas flow rates are 10-10,000 h ⁻¹ by GHSV and pressures between atmospheric and 20 kg / cm ² G.

Preferred examples of the fluorination method of the catalyst precursor supply HF and N ₂ at atmospheric pressure and 300-400 ° C., with the result that the HF concentration is 5-30% by volume, after which the fluorination reaction is started. After the hot spot passes through the precursor packing layer, the HF concentration and pressure are raised to at least 90% by volume and 10 kg / cm ² G, respectively, while being careful about exotherm and at least no more exothermic Processing continues under final conditions until not.

The combustion of the catalyst precursor described above and its fluorination thereof can be carried out in the same reactor as long as the reactor is made of Inconel or Haselloy, and the operation can be carried out conveniently.

A fluorination catalyst containing Ga, Cr, 0 and F as essential constituents and which can be prepared in the manner described above can be applied to the fluorination of halogenated hydrocarbons by HF and is particularly effective for the fluorination reaction of H-containing halogenated hydrocarbons. to be. In other words, coking proceeds more difficult in conventional fluorinated catalysts such as chromium oxyfluoride, and longer catalyst life can be achieved.

As used herein, "H-containing halogenated hydrocarbons" refers to halogenated hydrocarbons containing mainly H in C1-C4 molecules.

C ₃ H ₂ F ₄ Cl ₂ , and C ₃ HF ₄ Cl ₃ . In addition, the Cl of the hydrocarbon described above may be completely or partially substituted by Br. Among others, the fluorination catalyst of the present invention may be selected from CH ₂ Cl ₂ , CH ₂ FCl (HCFC-31), CHCl = CCl ₂ (trichloroethylene), CF ₃ CH ₂ Cl (HCHC-133a), CCl ₂ = CCl ₂ (Perchlorethylene), CF ₃ CHCl ₂ (HCFC-123), CF ₃ CHFCl (HCFC-124), etc. are effective in the fluorination reaction, these are CH ₂ F recently attracting attention as HFC without possible destruction of the ozone layer ₂ is believed to be a synthetic route for the preparation of (HFC-32), CH ₂ FCF ₃ (HFC-134a) and CF ₃ CHF ₂ (HFC-125).

The fluorination reaction may take a reaction method such as a fixed bed, a fluidized bed, a moving bed, and the like, but in general, the molar ratio of HF to halogenated hydrocarbons is 0.5-20, the temperature is 200-400 ° C., the pressure Is atmospheric pressure-20 kg / cm ² G and SV is 50-100,000 h ⁻¹ . Since caulking does not proceed easily in the fluorination catalyst of the present invention, the molar ratio of HF to halogenated hydrocarbons may be less than when conventional fluorination catalysts are used. Thus, not only can the catalyst life be increased, but also the high STY can be improved and thus the productivity can be increased.

Example

The invention will now be elucidated with reference to examples and comparative examples, but the invention is not, of course, limited to this description. By the way, Ga / Cr ratio represents the atomic ratio of each component contained in the catalyst measured by chemical analysis, and the molar ratio in a reaction example shows the molar ratio of HF with respect to halogenated hydrocarbon. SV is the value converted to standard conditions, and pressure is the gauge pressure.

(Catalyst Preparation Example 1)

In 240 g of pure water, 0.92 g of Ga (NO ₃ ) ₃ nH ₂ O (Ga content: 18.9 wt%) and 10 g of Cr (NO ₃ ) ₃ · 9H ₂ O were dissolved to obtain a Ga and Cr-containing aqueous solution.

Next, ammonia water was further added to the slurry of chromium hydroxide prepared by mixing aqueous ammonia (NH ₃ ) solution with Cr (NO ₃ ) ₃ . After adjusting the pH of the slurry (Cr content in slurry = 1.4% by weight) to 9 in this manner, the Ga and Cr-containing aqueous solution described above was prepared in about 20 minutes to prepare a slurry of hydroxide containing Ga and Cr. 840 g of slurry was added dropwise. The resulting slurry was filtered, washed sufficiently with pure water and then dried at 110 ° C. for 12 hours. The obtained solid was ground, mixed with graphite and pelletized by a tablet molding machine.

The pellet was filled with a combustion tube and burned at 400 ° C. for 4 hours under H ₂ air flow to obtain a catalyst precursor. The resulting precursor was charged into an Inconel reaction tube and initially pressurized in a 20 vol.% HF stream diluted with N ₂ at 350 ° C. and atmospheric pressure, then in a 100 vol.% HF stream while stopping the supply of N ₂ , and further pressure. Fluorination was performed in 100 vol.% HF stream while rising to 5 kg / cm ² G. After this treatment the composition of the pellets is tabulated:

Ga: 0.79, Cr: 58.6, 0: 19.1, F: 19.5

The analysis results show that the Ga / Cr ratio is 0.01.

(Catalyst Preparation Example 2)

The daffodil chromium slurry prepared by mixing Cr (NO ₃ ) ₃ aqueous solution with aqueous ammonia (NH ₃ ) with sufficient stirring was filtered, and the filtrate was sufficiently washed with pure water and then dried at 110 ° C. for 12 hours. The obtained solid was pulverized, and the resulting pulverized solution was slowly added dropwise to 50 g of an aqueous solution of GaCl (prepared by dissolving 0.43 g of GaCl _{3 in} 25 g of pure water). The wet powder was dried again at 110 ° C. for 12 hours, again mixed with graphite and pelletized by a pellet machine. Thereafter, the fluorination treatment was carried out in the same manner as in Preparation Example 1. After this treatment, the composition of the pellets is then tabulated.

Ga: 0.39, Cr: 57.5, 0: 18.0, F: 21.0

The analysis results show that the Ga / Cr ratio is 0.005.

(Comparative Catalyst Production Example 1)

A catalyst precursor containing no Ga was prepared according to the method of Preparation Example 1, except that Ga (N0 ₃ ) ₃ .H ₂ O was not added to the aqueous solution to be added dropwise to the chromium hydroxide slurry. The obtained catalyst precursor was fluorinated in the same manner as in Preparation Example 1. The composition of the pellets after this treatment is then tabulated.

Cr: 58.9, 0: 18.5, F: 20.6

(Comparative Catalyst Production Example 2)

A catalyst precursor having a large amount of Ga was prepared according to the method of Preparation Example 1 except that 18.4 g of Ga (NO ₃ ) ₃ nH ₂ 0 was added to the aqueous solution to be added dropwise to the slurry of chromium hydroxide. The fluorination treatment was conducted in the same manner as in Preparation Example 1. After this treatment, the composition of the pellets is then tabulated.

Ga: 12.4, Cr: 46.5, 0: 16.7, F: 21.4

The analysis results show that the Ga / Cr ratio is 0.2.

(Catalyst Preparation Example 3)

The catalyst was prepared in the same manner as in Preparation Example 1 except that the pellets molded in Preparation Example 1 were burned at 400 ° C. in an N ₂ stream. The Ga / Cr ratio measured by the analysis result was 0.01.

(Catalyst Preparation Example 4)

A solution prepared by dissolving 75 g of Cr (NO ₃ ) ₃ .9H ₂ O and 0.69 g of Ga (NO ₃ ) ₃ .nH ₂ O in 200 ml of pure water and 50 ml of 28% by weight ammonia was prepared. The flow rate of the two aqueous solutions was adjusted to 5-8.5 and added dropwise to a 1 l container containing 100 ml of pure water in about 20 minutes. The resulting slurry was filtered, washed sufficiently with pure water and dried at 110 ° C. for 12 hours. The catalyst was then prepared according to the method of Preparation Example 1. The Ga / Cr ratio measured from the analysis result was 0.01.

(Catalyst Preparation Example 5)

After dissolving 110 g of CrCl ₃ 6H ₂ O and 0.58 g of GaCl _{3 in} 78 g of pure water, 100 g of activated alumina was immersed in the solution to absorb the complete amount of the solution. The alumina was dried at 120 ° C. for 12 hours and filled with glass combustion tubes. Combustion was initially carried out for 3 hours at 350 ° C. in an air stream and then for 4 hours at 400 ° C. in an H ₂ stream. The resulting precursor was charged to a reaction tube made from Inconel, and the fluorination treatment was first performed at 20 ° C. HF stream treated with N ₂ at 350 ° C. atmospheric pressure, then in a 100 vol.% HF stream while the N ₂ feed was stopped, and further The pressure was carried out in a 100 vol% HF stream while raising the pressure to 3 kg / cm ² G. The Ga / Cr ratio measured from the analysis result was 0.008.

(Catalyst Preparation Example 6)

Preparation Example 1 except that an aqueous solution containing Ga, Cr and Zn was prepared by adding 2.97 g of Zn (NO ₃ ) ₂ .6H ₂ O to the Ga- and Cr-containing aqueous solution used in Preparation Example 1. The catalyst was prepared according to the method.

The Ga / Cr ratio was 0.01 and the Zn / Cr ratio was 0.04.

(Reaction Example 1)

After crushing and classifying the catalyst prepared in Preparation Example 1, 2.5 ml of particles of 0.71 mm −1 mm were filled in an Inconel reaction tube. Then, the fluorination reaction of HCFC-133a was performed under the following activity evaluation conditions and the HFC-134a yield was measured. Thereafter, the reaction conditions were changed to the next conditions where degradation would likely occur (hereinafter referred to as "accelerated decomposition conditions") and the reaction product was left for 15 hours. However, the HFC-134a yield remained constant at about 11%. Thereafter, the reaction conditions were returned to the activity evaluation conditions described above, and the activity drop was measured. Table 1 illustrates the HFC-134a yield before and after accelerated cracking and the yield ratio before and after accelerated cracking.

Active evaluation condition:

Temperature: 320 ℃,

Pressure: atmospheric pressure,

HF / HCFC-133a molar ratio: 8,

SV: 1,500 h ^-1

Accelerated decomposition conditions:

Temperature: 360 ℃,

Pressure: atmospheric pressure,

HF / HCFC-133a molar ratio: 1,

SV: 2,000 h ^-1

(Reaction Example 2)

The activity drop due to accelerated decomposition was measured according to reaction example 1 except that the catalyst prepared in catalyst preparation example 2 was used. Table the results in Table 1.

Comparative Example 1

The activity drop due to accelerated decomposition was measured according to reaction example 1 except that the catalyst prepared in comparative catalyst preparation example 1 was used. Table the results in Table 1.

Comparative Example 2

The activity drop due to accelerated decomposition was prepared according to Reaction Example 1, except that the catalyst prepared in Comparative Catalyst Preparation Example 1 was used. Table the results in Table 1.

Table 1

In the table, the yield represents the yield of HFC-134a and the yield ratio represents the yield ratio before and after accelerated decomposition.

In the case of the catalyst containing Ga added from the above-described results, it was understood that coking is unlikely to occur even when the catalyst is exposed to reaction conditions where decomposition is likely to occur, and consequently, it is understood that the activity drop is small. In addition, from Comparative Example 2, it was understood that if the amount of Ga added was too large, the activity of the catalyst would undesirably fall.

(Reaction Example 3-6)

The activity drop due to accelerated decomposition was measured in the same manner as in reaction example 1 except that catalyst preparation example 3 and the catalyst prepared in the following were used. Table 2 illustrates the HFC-134a yield ratio before and after accelerated cracking.

TABLE 2

In the table, the yield represents the yield of HFC-134a, and the yield ratio represents the yield ratio before and after accelerated decomposition.

(Reaction Example 7)

The fluorination reaction of HCFC-123 was carried out using the catalyst prepared in Preparation Example 1 according to Reaction Example 1 under the following conditions, and the activity drop was measured.

Active evaluation condition:

Temperature: 320 ℃,

Pressure: atmospheric pressure,

HF / HCFC-133a molar ratio: 4,

SV: 1,000 h ^-1

Accelerated decomposition conditions:

Temperature: 370 ℃,

Pressure: atmospheric pressure,

HF / HCFC-133a molar ratio: 1,

SV: 1,000 h ^-1

The yield ratio of HFC-125 before and after accelerated decomposition was 0.48.

As described above, since the fluorination catalyst according to the present invention has a long service life, it is possible to produce hydrocarbon fluoride having high productivity.

Claims (13)

A chromium-based fluorination catalyst having an atomic ratio of gallium to chromium of 0.001-0.1, wherein the chromium-based fluorination catalyst is used for fluorination of halogenated hydrocarbons containing chromium, gallium, oxygen and fluorine as essential components. The chromium-based fluorination catalyst according to claim 1, wherein the atomic ratio of gallium to chromium is 0.003-0.05. The chromium-based fluorination catalyst according to claim 1, further comprising at least one component selected from cobalt, nickel, zinc and cadmium in an atomic ratio of Cr to 0.001-0.5. A process for producing a chromium-based fluorination catalyst according to claim 1, which comprises contacting a catalyst precursor containing a chromium component and a gallium component with fluorine gas, hydrogen fluoride or a fluorine-containing hydrocarbon and carrying out a fluorination treatment to obtain a catalyst. 5. A process according to claim 4 wherein the catalyst precursor is an oxide and / or a hydroxide. A process according to claim 5, wherein the catalyst precursor is prepared by coprecipitation. A process according to claim 5, wherein the catalyst precursor is produced by impregnation. The process according to claim 4, wherein a catalyst precursor heat-treated at a temperature of 350-500 ° C. in an atmosphere containing a reducing gas is used. 9. A process according to claim 8 wherein the reducing gas is hydrogen. A method for fluorinating a halogenated hydrocarbon, characterized in that the hydrogen fluoride and the halogenated hydrocarbon are contacted in the gas phase in the presence of a chromium-based fluorination catalyst according to claim 1. The method of claim 10 wherein the halogenated hydrocarbon is a hydrogen-containing halogenated hydrocarbon. The method of claim 11, wherein the hydrogen-containing halogenated hydrocarbon is dichloromethane, chlorofluoromethane, 1-chloro-2,2,2-trifluoroethane, 1,1-dichloro-2,2,2-trifluoro Fluorine method characterized in that the component selected from ethane and 1-chloro-1,2,2,2-tetrafluoroethane. 13. The method of claim 12 wherein the hydrogen-containing halogenated hydrocarbon is 1-chloro-2,2,2-trifluoroethane.