WO2018139654A1 - Method for producing 1,1,2,2-tetrafluoropropane - Google Patents

Abstract

Provided is an economically advantageous method for producing 1,1,2,2-tetrafluoropropane (HFC-254cb), in which method HFC-254cb is obtained easily and at high selectivity using readily available raw materials. A method for producing 1,1,2,2-tetrafluoropropane characterized in that 1-chloro-1,1,2,2-tetrafluoropropane (HCFC-244cc) and hydrogen are reacted at a temperature exceeding 200°C in the presence of a catalyst.

Description

Method for producing 1,1,2,2-tetrafluoropropane

The present invention relates to a method for producing 1,1,2,2-tetrafluoropropane.

1,1,2,2-tetrafluoropropane (CHF ₂ —CF ₂ —CH ₃ (HFC-254cb)) is a rigid polyurethane foam blowing agent, solvent, cleaning agent, aerosol, refrigerant, working fluid, propellant, or It is useful as a raw material for them and fluororesins.

As a method for producing HFC-254cb, for example, 1,3,3-trichloro-1,1,2,2-tetrafluoropropane _{(CClF 2 -CF 2 -CHCl 2 (} HCFC-224ca), hereinafter also referred to as 224ca. ) And 1,1,1-trichloro-2,2,3,3-tetrafluoropropane (CHF ₂ —CF ₂ —CCl ₃ (HCFC-224 cc), hereinafter also referred to as 224 cc)) in the presence of a hydrogenation catalyst. A method for producing HFC-254cb by reacting with hydrogen is known (for example, see Patent Document 1).

However, in the reaction using 224ca, the selectivity of the target product, 254cb, is as low as 1% or less. In the reaction using 224 cc, the selectivity of 254 cb is low, and 3-chloro-1,1,2,2-tetrafluoropropane (CHF ₂ —CF ₂ —CH ₂ Cl (HCFC-244ca), hereinafter 244ca) is used. There is also a problem that it is difficult to obtain 224 cc as a raw material. Therefore, there is a demand for an economically advantageous method by which 254cb can be obtained simply and with high selectivity using readily available materials.

JP-A-2-204445

The present invention uses 1-chloro-1,1,2,2-tetrafluoropropane (CClF ₂ —CF ₂ —CH ₃ (HCFC-244cc), hereinafter also referred to as 244cc), which is an easily available raw material. Economically advantageous 254 cb of 1,1,2,2-tetrafluoropropane (CHF ₂ —CF ₂ —CH ₃ (HFC-254cb), hereinafter also referred to as 254cb)) can be obtained with high selectivity. The object is to provide a manufacturing method.

The present invention provides a method for producing 1,1,2,2-tetrafluoropropane having the following constitution.
[1] 1,1,2,2-Tetra characterized by reacting 1-chloro-1,1,2,2-tetrafluoropropane and hydrogen at a temperature exceeding 200 ° C. in the presence of a catalyst A method for producing fluoropropane.
[2] The 1,1,2,2-tetrafluoropropane according to [1], wherein the catalyst contains at least one selected from the group consisting of platinum, palladium, rhodium, ruthenium, nickel, rhenium, molybdenum and zirconium. Production method.
[3] The method for producing 1,1,2,2-tetrafluoropropane according to [2], wherein the catalyst is supported on a support containing at least one selected from the group consisting of activated carbon, alumina, zirconia and silica. .
[4] The method for producing 1,1,2,2-tetrafluoropropane according to [3], wherein the supported amount of the catalyst is 0.1 to 10% by mass with respect to 100% by mass of the carrier.

[5] The method for producing 1,1,2,2-tetrafluoropropane according to any one of [1] to [4], wherein the temperature of the reaction is 210 to 350 ° C.
[6] The amount of the hydrogen in the reaction is 0.1 to 5.0 mol with respect to 1 mol of the 1-chloro-1,1,2,2-tetrafluoropropane [1] to [5] A process for producing 1,1,2,2-tetrafluoropropane as described in any of the above.
[7] The method for producing 1,1,2,2-tetrafluoropropane according to any one of [1] to [6], wherein the reaction is performed in a gas phase, and the reaction time is 4 to 120 seconds.
[8] The method for producing 1,1,2,2-tetrafluoropropane according to any one of [1] to [7], wherein the reaction is performed in the presence of a diluent gas.
[9] The 1,1,2 as described in [8], wherein the amount of the dilution gas is 0.1-10 mol with respect to 1 mol of the 1-chloro-1,1,2,2-tetrafluoropropane , 2-tetrafluoropropane production method.
[10] General formula: CClF ₂ CF ₂ CH _a Cl _(3-a) (wherein a is an integer of 0 to 2) is reacted with hydrogen in the presence of a hydrogenation catalyst to give the 1-chloro The method for producing 1,1,2,2-tetrafluoropropane according to any one of [1] to [9], further comprising a step of obtaining -1,1,2,2-tetrafluoropropane.

In the present specification, for a halogenated hydrocarbon, the abbreviation of the compound is described in parentheses after the compound name, and the abbreviation is used instead of the compound name as necessary.

According to the present invention, it is possible to provide an economically advantageous production method of 254cb that can be easily obtained at a high selectivity by using 244cc that is easily available as a raw material.

Hereinafter, the present invention will be described in detail with reference to embodiments. In the present embodiment, 254 cb is produced by reacting 244 cc with hydrogen at a temperature exceeding 200 ° C. in the presence of a catalyst.

In the production method of this embodiment, the method of reacting 244 cc with hydrogen in the presence of a catalyst is not particularly limited except for the reaction temperature. For example, the reaction between 244 cc and hydrogen is performed by supplying 244 cc and hydrogen to a reaction field where the catalyst is disposed (usually in a reactor in which the catalyst is accommodated). Hereinafter, a method of supplying 244 cc and hydrogen to react in a reactor containing a catalyst will be described, but the present invention is not limited thereto.

The reaction between 244 cc and hydrogen may be performed in the liquid phase or in the gas phase. It is preferable to carry out the reaction in the gas phase because there are advantages that the reaction time can be shortened and the production of by-products can be suppressed.

The manufacturing method of this embodiment can be performed by either a batch method or a continuous method. In a continuous production method, 244 cc and hydrogen are supplied to a reactor containing a catalyst, 244 cc is reacted in the reactor, and hydrogen is brought into contact with the catalyst, and the 254 cb reactor obtained by the reaction is used. The removal from is performed continuously.

The timing of supplying 244 cc and hydrogen into the reactor containing the catalyst is not particularly limited in both batch and continuous methods. That is, either one may be supplied first and the other may be supplied later, or both may be supplied simultaneously. When either one of 244 cc and hydrogen is supplied first, the previously supplied component is retained in the reactor, and the other component is supplied to the reactor so that 244 cc, hydrogen, catalyst, May be contacted for a predetermined time. When 244 cc and hydrogen are simultaneously supplied into the reactor, 244 cc and hydrogen may be supplied to the reactor from separate supply pipes, or may be mixed in advance and supplied from one supply pipe. In the case of a continuous system, the heat of adsorption of the catalyst, 244 cc, is generated at the beginning of the supply of 244 cc. Therefore, it is more convenient to supply 244 cc first and add hydrogen after the heat of adsorption has subsided. Is preferable.

The manufacturing method of the present embodiment is preferably a continuous method in terms of manufacturing efficiency. Hereinafter, unless otherwise specified, the manufacturing method of the present embodiment will be described with respect to a method of reacting 244 cc with hydrogen in a gas phase in a continuous manner.

In the production method of the present embodiment, the amount of hydrogen used is preferably about 0.1 to 5.0 moles, more preferably 0.5 to 3.0 moles per mole of 244 cc. If the amount of hydrogen is not less than the lower limit, the conversion rate is improved. Moreover, if the quantity of hydrogen is below the said upper limit, the production | generation of a by-product can be suppressed. In addition, if the amount of hydrogen is less than or equal to the above upper limit value, hydrogen can be prevented from flowing through the reactor without being reacted, so that it tends to be advantageous in terms of production and economy. In addition, when making it react by a continuous type, the molar ratio of 244cc and hydrogen is represented by the ratio of the molar flow rate per unit time.

(244cc)
244 cc used in the production method of the present embodiment is a compound represented by the general formula (A): CClF ₂ CF ₂ CH _a Cl _(3-a) (wherein a is an integer of 0 to 2). Hereinafter, the compound (A) can be easily produced by bringing it into contact with hydrogen in the presence of a hydrogenation catalyst to cause a reduction reaction. In this reduction reaction, one of the compounds (A) in which a is an integer of 0 to 2 may be used alone, or two or more compounds (A) having different a may be used as raw materials. It is good.
In the above general formula (A), a compound in which a is 0 is 1,1,1,3-tetrachloro-2,2,3,3-tetrafluoropropane (CClF ₂ -CF ₂ -CCl ₃ (CFC-214cb ), Hereinafter also referred to as 214cb), the compound in which a is 1 is 224ca, and the compound in which a is 2 is 1,3-dichloro-1,1,2,2-tetrafluoropropane (CCIF ₂ -CF ₂ -CClH ₂ (HCFC-234cc), hereinafter also referred to as 234cc).

214cb and 224ca can be obtained by reacting tetrafluoroethylene (TFE) with one or both of CCl ₄ and CHCl ₃ in the presence of a Lewis acid catalyst such as aluminum chloride.

234 cc is obtained by hydrogenating one or both of 214cb and 224ca obtained above in the presence of, for example, a palladium catalyst, or reacting TFE and CH ₂ Cl ₂ in the presence of a Lewis acid catalyst as described above. Can be obtained.

Reduction reaction by contacting a compound represented by the above general formula (A) obtained by these methods, specifically 214cb, 224ca, 234cc, etc. with hydrogen in the presence of a hydrogenation catalyst such as a palladium catalyst. By doing so, a composition containing 244 cc can be obtained.

The composition containing 244 cc obtained by the above method may contain 244 cc, TFE, 214 cb, 224 ca, 234 cc, CH ₂ Cl ₂ , CCl ₄ , CHCl _3, etc. in addition to 244 cc. is there. In the production method of the present embodiment, the composition containing 244 cc obtained by the above method may be used as a raw material as it is, and known methods such as distillation, extractive distillation, azeotropic distillation, membrane separation, two-layer separation, adsorption, etc. Thus, a material having an increased purity of 244 cc may be used as a raw material. From the viewpoint of improving the conversion rate of 244 cc and the selectivity of 254 cb, it is preferable to use a material obtained by removing 214 cb, 224 ca, 234 cc, etc. to increase the purity of 244 cc as the raw material of the manufacturing method of this embodiment.

In the production method of the present embodiment, 244 cc and other compounds other than hydrogen may be supplied to the reactor containing the catalyst. Examples of other compounds include the above-mentioned 244 cc production raw materials and by-products produced in addition to 244 cc when 244 cc is produced. When the above-mentioned other compounds are supplied, by-products generated from the other compounds should be removed by known means such as distillation, extractive distillation, azeotropic distillation, membrane separation, two-layer separation, and adsorption. Is possible. The other compound is preferably a compound that is inactive under the reaction conditions of the reaction between 244 cc and hydrogen.

(catalyst)
The catalyst used in the production method of the present invention is not particularly limited as long as it has a function of promoting the reaction between 244 cc and hydrogen. Catalysts include Group 4 elements such as zirconium, Group 6 elements such as molybdenum, Group 7 elements such as rhenium, Group 8 elements such as iron, ruthenium and osmium, and Group 9 elements such as cobalt, rhodium and iridium. Examples thereof include metals such as elements, Group 10 elements such as palladium, nickel and platinum, and Group 11 elements such as gold.

Among them, the catalyst preferably contains at least one metal selected from platinum, palladium, rhodium, ruthenium, nickel, rhenium, molybdenum and zirconium from the viewpoint of improving the conversion rate of 244 cc and the selectivity of 254 cb.

The catalyst may be one of the above metals or two or more. The catalyst composed of two or more metals may be a mixture of two or more metals or an alloy of two or more metals.

As the catalyst, group 9 elements, group 10 elements palladium and platinum are particularly preferable in that the selectivity of 254cb is further improved.

The catalyst is preferably used by being supported on a carrier in order to improve the reactivity. The carrier is not particularly limited as long as it can sufficiently carry the catalyst. The carrier preferably includes at least one carrier selected from alumina, activated carbon, zirconia, and silica. As the carrier, alumina and activated carbon are preferable, and activated carbon is more preferable in that the conversion rate of 244 cc and the selectivity of 254 cb are further improved. One type of carrier may be used alone, or two or more types may be used in combination.

Examples of the activated carbon include activated carbon obtained from plant raw materials such as wood, charcoal, fruit husk and coconut husk, and mineral raw materials such as peat, lignite and coal. As the carrier for supporting the hydrogenation catalyst, activated carbon obtained from plant raw materials is preferable from the viewpoint of catalyst durability, and coconut shell activated carbon is particularly preferable. The shape of the activated carbon may be any shape, and examples thereof include formed coal having a length of about 2 to 10 mm, crushed coal having a size of about 4 to 50 mesh, and granular coal.

As specific examples of the catalyst supported on the carrier, alumina supporting palladium, activated carbon supporting palladium, activated carbon supporting platinum, and the like are preferable because the catalytic activity can be maintained for a long time.

When the catalyst is used on a carrier, the amount of the catalyst supported on the carrier is preferably 0.1 to 10% by mass, more preferably 0.5 to 3% by mass, more preferably 1.0 to 3% by mass is more preferable, and 1.5 to 2.5% by mass is most preferable. If the supported amount of the catalyst is at least the lower limit value, the reaction rate between the raw material and hydrogen and the conversion rate of 244 cc can be improved. If the supported amount of the catalyst is not more than the upper limit value, it is easy to suppress an excessive temperature rise of the catalyst due to the heat of reaction, and it is easy to reduce the production of by-products.

(Reaction conditions)
In the production method of the present embodiment, the reaction temperature when 244 cc and hydrogen are reacted in a gas phase is a temperature exceeding 200 ° C., preferably about 210 to 350 ° C., more preferably 250 to 300 ° C. If the reaction time is not less than the lower limit, the conversion rate of 244 cc is good, and if the reaction time is not more than the upper limit, the production of by-products can be suppressed and catalyst deterioration can be suppressed. The reaction temperature refers to the temperature in the reactor where 244 cc reacts with hydrogen, more specifically, the temperature of the catalyst.

The contact time (reaction time) of 244 cc and hydrogen in the reactor is preferably about 4 to 120 seconds, more preferably about 8 to 100 seconds. If the contact time is equal to or greater than the lower limit value, the conversion rate of 244 cc is good, and if the contact time is equal to or less than the upper limit value, generation of by-products can be suppressed. The contact time can be controlled by adjusting the supply amount (flow rate) of 244 cc and hydrogen to the reactor.

The reaction pressure can be normal pressure or under pressure, but it is preferable to carry out the reaction at normal pressure from the viewpoint of ease of industrial implementation.

In addition to 244 cc and hydrogen, a diluent gas may be further supplied into the reactor. By supplying the diluting gas into the reactor and allowing it to flow and adjusting the concentration of 244 cc and hydrogen contacted with the catalyst, an excessive temperature rise of the catalyst due to the heat of reaction can be suppressed, and the reaction can be performed safely. As the dilution gas, an inert gas such as nitrogen gas or a rare gas, or chlorofluorocarbons inert to the hydrogenation reaction of this embodiment can be used. Of these, nitrogen gas is preferred as the dilution gas. Dilution gas may be used individually by 1 type, and may use 2 or more types together.

The amount of dilution gas supplied into the reactor is easy to maintain the maximum temperature of the catalyst low, easily reduce the production of by-products, and suppress the deterioration of the catalyst and maintain the catalyst activity for a long time. 0.1 mol or more is preferable with respect to 1 mol of 244cc, and 0.5 mol or more is more preferable. Further, the supply amount of the dilution gas is preferably 10 mol or less, more preferably 5 mol or less, and further preferably 3 mol or less with respect to 1 mol of 244 cc from the viewpoint of the recovery rate of the dilution gas.

The reactor used in the production method of the present embodiment is not particularly limited as long as it is a reactor that can be filled with a catalyst, preferably a catalyst support, to form a catalyst layer. Examples of the material for the reactor include glass, iron, nickel, and alloys containing these as main components.

In such a reactor, the catalyst (preferably a catalyst-supporting carrier) is accommodated to form a catalyst layer as a reaction field. The catalyst (preferably catalyst-supporting carrier) may be accommodated in either a fixed bed type or a fluidized bed type. In addition, in the case of a fixed bed type, it may be either a horizontal fixed bed type or a vertical fixed bed type, but in a mixed gas composed of multiple components, the concentration distribution of each component is generated depending on the location due to the difference in specific gravity. It is preferable to use a vertical fixed floor type.

The 244 cc and hydrogen supplied to the reactor are kept as they are when they are mixed in advance, or they are usually mixed in the vicinity of the inlet of the reactor in the direction from the inlet side to the outlet when they are separated. It distribute | circulates so that a catalyst layer may be passed.

The product gas discharged from the outlet of the reactor contains 244 cc which is an unreacted raw material, hydrogen, various by-products and HCl in addition to 254 cb which is a target substance. The by-product is, for example, a compound having 6 carbon atoms (C6 compound) in which 244 cc and 254 cb produced, 244 cc or 254 cb are bonded (C1 compound), a compound having 1 carbon (C1 compound) in which 244 cc or 254 cb is decomposed, or 2 carbon atoms. (C2 compound), propane, 1-chloro-1,1,2-trifluoropropane (CClF ₂ —CHF—CH ₃ (HCFC-253ec), hereinafter also referred to as 253ec)), 1,1,2- Trifluoropropane (CHF ₂ —CHF—CH ₃ (HCFC-263eb), hereinafter also referred to as 263eb), 1,2,2-trifluoropropane (CH ₂ F—CF ₂ —CH ₃ (HCFC-263ca)), hereinafter also referred to as 263ca.), 2,2- difluoropropane _{(CH 3 -CF 2 -CH 3 (} HCF -272ca), below, it is also referred to as 272ca.) And the like. In order to remove HCl, the product gas is usually subjected to alkali cleaning and then subjected to dehydration. In this specification, the gas obtained after HCl is removed in this way is referred to as outlet gas.

Components other than 254cb in the outlet gas can be removed to the extent desired by distillation or the like. Further, 244 cc in the outlet gas can also be separated by distillation or the like. The separated 244 cc can be recycled as a production raw material of 254 cb by returning it to the reactor again. By recycling the unreacted raw material in this manner, the productivity of 254cb as a whole can be increased even when the conversion rate of 244cc in the reaction of 244cc and hydrogen is low.

In addition, when performing the manufacturing method of this embodiment in a liquid phase, you may perform reaction of 244cc and hydrogen using a solvent, and without solvent. When the reaction between 244 cc and hydrogen is carried out using a solvent, alcohols such as ethanol and isopropyl alcohol, acetic acid, ethyl acetate, pyridine and the like can be used as the solvent. When it is performed without a solvent, 244 cc can be liquefied by pressurization. When the production method of the present embodiment is carried out in the liquid phase, the reaction temperature is preferably from room temperature (about 25 ° C.) to about 150 ° C., and the reaction pressure is preferably from atmospheric pressure to about 5 MPa. The reaction time is usually preferably about 1 to 72 hours. When the production method of this embodiment is performed in a liquid phase and in a batch mode, the reaction time is preferably 1 to 9 hours.

As described above, according to the manufacturing method of the present embodiment, 244cb can be easily obtained with high selectivity using 244cc that is easily available as a raw material, which is economically advantageous.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following description. Examples 1 to 13 are examples of the present invention, and Examples 14 to 19 are comparative examples.

(1) Production of 224ca According to the following reaction formula, 1,1,3-trichloro-2,2,3,3-tetrafluoropropane (224ca) was produced by the following procedure.

CHCl ₃ + TFE → 224ca

First, anhydrous aluminum chloride (25 g, 0.19 mol), CHCl ₃ (500 g, 4.19 mol) and 224ca (100 g, 0.45 mol) were put into a 500 mL stainless steel autoclave and degassed with stirring, and then TFE was added. Was supplied until the inside of the autoclave became 0.05 MPa, and the inside of the autoclave was heated to 80 ° C. Thereafter, TFE was further supplied while maintaining the pressure in the autoclave at 0.8 MPa. The total amount of TFE supplied to the autoclave was 0.17 kg (1.65 mol).

After further stirring for 1 hour, the reaction solution was cooled to room temperature and analyzed by gas chromatography. The conversion of CHCl ₃ was 33% and the selectivity of 224ca was 84%. To the crude liquid obtained by filtering the liquid after the reaction, 102 g of molecular sieve 4A was added and stirred overnight to dehydrate. 224ca (230 g, 1.05 mol) was manufactured by distilling and purifying the crude product obtained by separating the stirred crude liquid by filtration.

(2) Production of 244cc 3-Chloro-1,1,2,2-tetrafluoropropane (244cc) was obtained by the following method using 224ca obtained by the above method as a raw material.

First, a gas phase reactor (made of SUS316, diameter 25 mm, length 30 cm) composed of a cylindrical reaction tube equipped with an electric furnace was charged with activated carbon pellets (15 g) supporting palladium at a ratio of 2.0 mass%, The temperature was raised to 130 ° C. while flowing nitrogen (N ₂ ) gas (500 NmL / min). While maintaining the reactor at atmospheric pressure (1 atm), the catalyst was dried until the moisture in the crude gas after passing through the reactor became 20 ppm or less. After the drying of the catalyst was completed, the supply of nitrogen was stopped, the reaction tube was heated to 200 ° C. while supplying hydrogen (180 mL / min), and then 224ca (0.44 g / min) was supplied.

The crude gas from the reaction tube was washed with water, and then acid and moisture were removed through an alkali washing tower and molecular sieve 5A, and then collected in a cold trap. When the collected crude product was analyzed by gas chromatography, the conversion rate of 224ca was 98%, and 234cc was obtained with a selectivity of 24% and 244cc with a selectivity of 70%. A total of 500 g (2.27 mol) of 224ca was reacted above to give 298 g of crude product.

The obtained crude product was subjected to normal pressure rectification in a 25-stage rectification column to obtain 244 cc (210 g, 1.4 mol).

[Example 1]
First, a gas phase reactor (made of Inconel (registered trademark) 600, a reaction tube having a diameter of 26 mm and a length of 60 cm) including a cylindrical reaction tube equipped with a salt bath furnace is used with respect to 100% by mass of activated carbon (crushed coal). A palladium catalyst supporting palladium at a ratio of 0.5% by mass was filled to form a catalyst layer having a height of 40 cm. After heating the reactor to 250 ° C. in a salt bath furnace, 244 cc and hydrogen are supplied so that the ratio of the molar flow rate per unit time of 244 cc and hydrogen (H ₂ ) (244 cc / H ₂ ) is halved. For 30 seconds to obtain a product gas.

The generated gas was analyzed using gas chromatography (GC). DB-1301 (length 60 m × inner diameter 250 μm × thickness 1 μm, manufactured by Agilent Technologies) was used for the column. From the GC analysis results, the conversion and selectivity were calculated by the following formulas.

Conversion of raw material compound (%) = {(amount of raw material compound supplied to reactor (mol) −amount of raw material compound contained in product gas (mol)) / amount of raw material compound supplied to reactor (mol) } × 100
Selectivity of product compound (%) = {amount of product compound contained in product gas (mole) / amount of raw material compound consumed in reaction (mole)} × 100

The conversion rate of the raw material compound 244cc, the selectivity of each compound produced, the reaction conditions (type of catalyst, 244cc and hydrogen supply molar ratio to the reactor, contact time, salt bath furnace temperature (reaction temperature)) Table 1 also shows.

[Examples 2 to 8]
The reaction was performed in the same manner as in Example 1 except that the reaction conditions were changed as shown in Tables 1 and 2. Tables 1 and 2 show the conversion rate of 244 cc and the selectivity of each compound produced together with the reaction conditions. In Examples 5 and 6, in addition to 244 cc, hydrogen, nitrogen was also supplied. The nitrogen supply molar ratio is also shown in Table 2.

[Examples 9 to 13]
The reaction was performed in the same manner as in Example 1 except that the catalyst was changed to activated carbon pellets carrying palladium at a ratio of 2.0% by mass and the reaction conditions were changed as shown in Table 3. The conversion rate of 244 cc and the selectivity of each compound produced are shown in Table 3 together with the reaction conditions.

[Examples 14 to 17]
The raw material was changed from 244cc to 214cb, and activated carbon pellets carrying palladium at a ratio of 2.0% by mass were used as a catalyst. Moreover, reaction conditions were set as shown in Table 4. The reaction was performed in the same manner as in Example 1 except for these. The composition of the product gas was analyzed by GC in the same manner as in Example 1, and the conversion rate of 214 cb as a raw material and the selectivity of each compound produced were calculated by the above formula.

The conversion rate of 214cb and the selectivity of each compound produced were combined with the reaction conditions (type of catalyst, 214cb to reactor, hydrogen and nitrogen supply molar ratio, contact time, salt bath furnace temperature (reaction temperature)). Table 4 shows.

[Examples 18 to 19]
The reaction was carried out in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 5. Table 5 shows the conversion rate of 244 cc and the selectivity of each compound produced together with the reaction conditions.

From Tables 1 to 5, the production methods of Examples 1 to 13 (Examples) have a high selectivity of 88% or more using 244 cc, which is easily available, compared to the production methods of Examples 14 to 19 (Comparative Examples). It can be seen that 254cb is obtained.

Claims (10)

1. 1,1,2,2-tetrafluoropropane characterized by reacting 1-chloro-1,1,2,2-tetrafluoropropane with hydrogen at a temperature exceeding 200 ° C. in the presence of a catalyst Manufacturing method.
2. The method for producing 1,1,2,2-tetrafluoropropane according to claim 1, wherein the catalyst contains at least one selected from the group consisting of ruthenium, rhodium, palladium, nickel, rhenium, molybdenum, platinum and zirconium. .
3. 3. The method for producing 1,1,2,2-tetrafluoropropane according to claim 2, wherein the catalyst is supported on a support containing at least one selected from the group consisting of activated carbon, alumina, zirconia and silica.
4. The method for producing 1,1,2,2-tetrafluoropropane according to claim 3, wherein the supported amount of the catalyst is 0.1 to 10% by mass with respect to 100% by mass of the carrier.
5. The process for producing 1,1,2,2-tetrafluoropropane according to any one of claims 1 to 4, wherein the temperature of the reaction is 210 to 350 ° C.
6. The amount of the hydrogen in the reaction is 0.1 to 5.0 mol per 1 mol of the 1-chloro-1,1,2,2-tetrafluoropropane. 2. A process for producing 1,1,2,2-tetrafluoropropane as described in the item.
7. The reaction according to any one of claims 1 to 6, wherein the reaction is performed in a gas phase, and the contact time of the hydrogen and the 1-chloro-1,1,2,2-tetrafluoropropane is 4 to 120 seconds. Of 1,1,2,2-tetrafluoropropane.
8. The method for producing 1,1,2,2-tetrafluoropropane according to any one of claims 1 to 7, wherein the reaction is carried out in the presence of a diluent gas.
9. The 1,1,2,2 according to claim 8, wherein the amount of the dilution gas is 0.1 to 10 mol per 1 mol of the 1-chloro-1,1,2,2-tetrafluoropropane. A process for the production of tetrafluoropropane.
10. The general formula: CClF ₂ CF ₂ CH _a Cl _(3-a) (wherein a is an integer of 0 to 2) is reacted with hydrogen in the presence of a hydrogenation catalyst to give the 1-chloro-1, The method for producing 1,1,2,2-tetrafluoropropane according to any one of claims 1 to 9, further comprising a step of obtaining 1,2,2-tetrafluoropropane.