KR100854982B1 - Process for production of 1,1,1,2-tetrafluoroethane and/or pentafluoroethane and applications of the same - Google Patents

Abstract

Hydrogen fluoride, comprising a main product comprising 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, and an impurity component comprising hydrogen fluoride and at least an unsaturated compound as an azeotrope with the main product; A process for purifying crude product obtained by reacting trichloroethylene and / or tetrachloroethylene to produce high purity 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, wherein the purification process Includes a step and a distillation step of reducing the content of unsaturated compounds contained in the crude product by contacting the mixture obtained by newly adding hydrogen fluoride to the crude product in a gas phase.

Description

PROCESS FOR PRODUCTION OF 1,1,1,2-TETRAFLUOROETHANE AND / OR PENTAFLUOROETHANE AND APPLICATIONS OF THE SAME

The present invention relates to a process for the preparation of 1,1,1,2-tetrafluoroethane and / or pentafluoroethane and its use.

As a method for producing 1,1,1,2-tetrafluoroethane (HFC-134a or CF ₃ CH ₂ F) and pentafluoroethane (HFC-125 or CF ₃ CHF ₂ ), the following methods are conventionally known. come.

As a method for producing 1,1,1,2-tetrafluoroethane, for example, a method for producing trichloroethylene and hydrogen fluoride in the presence of a fluorine catalyst is known. Moreover, as a manufacturing method of pentafluoroethane, the manufacturing method which makes tetrachloroethylene and hydrogen fluoride react in presence of a fluorination catalyst is known. When 1,1,1,2-tetrafluoroethane and pentafluoroethane are produced by these methods, various impurities are produced as by-products depending on the reaction conditions used. These impurities include unsaturated compounds such as CF ₂ = CClF, CF ₂ = CHCl, CHF = CClF, CClF = CHCl, CHCl = CHF, CF ₂ = CHF, and CF ₂ = CClF, and CCl ₂ F ₂ , CH ₂ Chlorofluorocarbons such as ClF, CH ₂ ClCClF ₂ , CF ₃ CHCl ₂ and CF ₃ CClF ₂ , and hydrofluorocarbons such as CH ₂ F ₂ , CF ₃ CH ₃ and CHF ₂ CHF ₂ .

Of these impurities, hydrofluorocarbons do not cause any problems as long as they are present in small amounts, but it is essential to reduce the content of the unsaturated compound and the chlorofluorocarbon as much as possible. These can be reduced to a certain range by fractional distillation or the like. However, impurities having boiling points close to those of 1,1,1,2-tetrafluoroethane and pentafluoroethane are very difficult to be removed by fractional distillation to sufficiently low levels that are substantially absent. In addition, it is difficult to remove the impurities forming the azeotropic composition and the azeotropic composition in the same manner as the former. For this reason, various methods have been proposed as a method for solving these problems.

For example, by reacting CF ₃ CH ₂ F with hydrogen fluoride as an azeotropic component in the presence of a fluorination catalyst, an unsaturated compound (mainly CF ₂ = CHCl) contained as an impurity in crude CF ₃ CH ₂ F from which some hydrogen chloride has been removed to some extent is removed. A method of purifying (Japanese Patent Laid-Open No. 6-184015) is known. However, the process is effective for the production of unsaturated compounds and defluorination catalysts by dehalogenation of intermediate 2-chloro-1,1,1-trifluoroethane (CF ₃ CH ₂ Cl) contained in the target CF ₃ CH ₂ F. Technical issues such as shortening the lifespan remain.

The problem solved by the present invention is to provide a novel method for producing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane and its use for solving the problems of the prior art.

In view of the above situation, as a result of careful consideration by the present inventors to find a method for producing industrially usable and economical 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, 1 Hydrogen fluoride and trichloro consisting of a main product comprising 1,1,2-tetrafluoroethane and / or pentafluoroethane, an impurity component comprising hydrogen fluoride and at least an unsaturated compound as an azeotropic component with the main product. A process for producing high purity 1,1,1,2-tetrafluoroethane and / or pentafluoroethane by the step of purifying crude product obtained by reacting low ethylene and / or tetrachloroethylene, wherein the purification step The mixture obtained by adding fresh hydrogen fluoride to the crude product was brought into contact with the fluorination catalyst in the gas phase to reduce the amount of unsaturated compounds contained in the crude product. The present invention by using a manufacturing method which comprises the steps and the distillation step of cattle found that can solve the problems has been achieved.

That is, this invention includes the method of the following (1)-(13), for example.

(1) a main product comprising 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, comprising an impurity component containing hydrogen fluoride and at least an unsaturated compound as an azeotropic component with the main product, In the method for producing high purity 1,1,1,2-tetrafluoroethane and / or pentafluoroethane by a step of purifying a crude product obtained by reacting hydrogen fluoride with trichloroethylene and / or tetrachloroethylene. The purification step includes a step of reducing the content of unsaturated compounds contained in the crude product by contacting the mixture obtained by hydrogen fluoride newly added to the crude product with a fluorination catalyst in a gas phase, and a distillation process. Process for preparing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane.

(2) The content of 1,1,1,2-tetrafluoroethane and / or pentafluoroethane according to (1), wherein the content of hydrogen chloride contained as impurities in the crude product is 2 mol% or less. Manufacturing method.

(3) The concentration of 1,1,1,2-tetrafluoroethane and / or pentafluoroethane contained in the crude product according to (1) or (2), wherein the concentration is 70 mol% or more. Process for preparing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane.

(4) The method of any one of (1) to (3), wherein the unsaturated compound is 1,1-difluoro-2-chloroethylene, 1,2-difluoro-1-chloroethylene, 1-chloro 1,1, characterized in that at least one compound selected from the group consisting of -2-fluoroethylene, 1,1,2-trifluoroethylene and 1-chloro-1,2,2-trifluoroethylene Method for preparing 1,2-tetrafluoroethane and / or pentafluoroethane.

(5) In any one of (1) to (4), the fluorination catalyst is selected from the group consisting of Cu, Mg, Zn, Pb, V, Bi, Cr, In, Mn, Fe, Co, Ni, and Al. A process for producing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, comprising at least one metal element selected.

(6) 1,1,1,2-tetrafluoro, according to any one of (1) to (5) above, wherein the contact temperature between the mixture and the fluorination catalyst is in the range of 130 to 280 ° C. Process for preparing ethane and / or pentafluoroethane.

(7) Said main product containing 1,1,1,2- tetrafluoroethane, hydrogen fluoride and an at least unsaturated compound in any one of said (1)-(6) as an azeotropic component with the said main product 1,1,1,2- characterized in that the mixture obtained by newly adding hydrogen fluoride to a crude product composed of an impurity component included therein is in contact with the fluorination catalyst in the gas phase to reduce the content of the unsaturated compound contained in the crude product. Method for preparing tetrafluoroethane and / or pentafluoroethane.

(8) The 1,1,1,2-tetrafluoroethane and / or pentafluoro, according to (7), wherein the contact temperature between the mixture and the fluorination catalyst is in the range of 130 to 200 ° C. Method for producing ethane.

(9) The process according to any one of (1) to (8), further comprising the step of separating hydrogen fluoride in the distillation step and recycling the separated hydrogen fluoride in a step for obtaining the crude product. A method for producing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane.

(10) 1,1,1,2-tetrafluoroethane obtained by the production method according to any one of (1) to (9), wherein the 1,1,1,2-tetrafluoroethane is used. The total content of the chlorine-containing compound is 1,1,1,2-tetrafluoroethane, characterized in that 2 ppm by volume or less.

(11) A process for producing pentafluoroethane and / or hexafluoroethane, wherein 1,1,1,2-tetrafluoroethane and fluorine gas according to (10) are reacted in the presence of a diluent gas. .

(12) An etching gas comprising pentafluoroethane and / or hexafluoroethane obtained by the production method described in the above (11).

(13) A cleaning gas comprising pentafluoroethane and / or hexafluoroethane obtained by the production method described in (11) above.

According to the present invention, by reducing the content of unsaturated impurities contained in 1,1,1,2-tetrafluoroethane and / or pentafluoroethane, 1 can be advantageously used as a low temperature refrigerant, etching gas or cleaning gas. Industrially advantageous production methods and their use for obtaining, 1,1,2-tetrafluoroethane and / or pentafluoroethane can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

As a method for producing CF ₃ CH ₂ F, for example, a method of producing trichloroethylene and hydrogen fluoride by reacting in two steps in the presence of a fluorination catalyst is known. Further, as the production method of the CF ₃ CHF _2, for example, in the presence of a fluorination catalyst it is known a method of producing by reacting tetrachlorethylene and hydrogen fluoride to the two processes. In the case of producing CF ₃ CH ₂ F and CF ₃ CHF ₂ using these methods, impurities that are difficult to separate from the target CF ₃ CH ₂ F and CF ₃ CHF ₂ , even when purified by a generally practical distillation process or the like, It is contained. As these impurities, for example, the above unsaturated compounds, chlorofluorocarbons, hydrofluorocarbons and the like can be mentioned. It is necessary to remove as many of these impurities as possible to obtain high purity.

The process for producing 1,1,1,2-tetrafluoroethane and / or pentafluoroethane of the present invention comprises a main product comprising 1,1,1,2-tetrafluoroethane and / or pentafluoroethane. High purity 1, by a step of purifying a crude product obtained by reacting hydrogen fluoride with trichloroethylene and / or tetrachloroethylene comprising an impurity component containing hydrogen fluoride and at least an unsaturated compound as an azeotropic component with the main product. In the process for producing 1,1,2-tetrafluoroethane and / or pentafluoroethane, the purification step is carried out by contacting the mixture obtained by newly adding hydrogen fluoride to the crude product in contact with the fluorination catalyst in the gas phase. And a process for reducing the content of unsaturated compounds contained in the product and a distillation process.

Many compounds of hydrofluorocarbons are known to form an azeotrope with hydrogen fluoride. In addition, CF ₃ CH ₂ F and CF ₃ CHF ₂ form an azeotrope with hydrogen fluoride. For example, the molar ratio of the azeotropic mixture of CF ₃ CH ₂ F and hydrogen fluoride is HF / CF ₃ CH ₂ F = about 0.12. For example, Japanese Patent Laid-Open No. 6-184015 discloses a mixture containing an azeotropic mixture and unsaturated impurities such as 1,1-difluoro-2-chloroethylene (CF ₂ = CHCl) at a temperature of 200 to 380 ° C. A method of reducing the unsaturated compound by contacting with a chromium-based catalyst is described. However, this results in the dehalogenation reaction of 2-chloro-1,1,1-trifluoroethane (CF ₃ CH ₂ Cl) contained in the mixture when the contact temperature is increased, resulting in 1,1-di There is a problem that fluoro-2-chloroethylene is produced and coking of the catalyst surface proceeds along it, and the catalyst life is shortened. In the present invention, hydrogen fluoride is newly added to a main product comprising CF ₃ CH ₂ F and / or CF ₃ CHF ₂ , a mixture containing hydrogen fluoride and at least one unsaturated compound as an azeotropic component with the main product. By contacting this mixture with the fluorination catalyst in a gaseous state, the advantage is obtained that the content of the unsaturated compound can be reduced and the catalyst life can be extended without loss of the desired product.

After reacting the trichloroethylene and hydrogen fluoride, the CF ₃ CH ₂ F crude product obtained by performing the crude purification step is prepared as azeotropic components in the production of hydrogen fluoride, at least one unsaturated compound and the CF ₃ CH ₂ F. CF ₃ CH ₂ Cl as intermediate. In general, the concentration of CF ₃ CH ₂ Cl is about 10 mol% or less, and the concentration of the target CF ₃ CH ₂ F is 70 mol% or more. CF ₃ CH ₂ Cl of the intermediate forms an azeotropic mixture with the hydrogen fluoride. The molar ratio of the azeotropic mixture is HF / CF ₃ CH ₂ Cl = about 1.0.

In addition, the total content of the unsaturated compound is generally about 0.4 to 0.9 mol%, depending on the catalyst and reaction conditions used. As the unsaturated compound, 1,1-difluoro-2-chloroethylene, 1,2-difluoro-1-chloroethylene, 1-chloro-2-fluoroethylene, 1,1,2-trifluoro Mention may be made of ethylene and 1-chloro-1,2,2-trifluoroethylene. The molar ratio of the azeotropic mixture of CF ₃ CH ₂ F and hydrogen fluoride is HF / CF ₃ CH ₂ F = about 0.12, therefore, the amount of newly added hydrogen fluoride is preferably higher. Wherein the CF ₃ CH ₂ F with the molar ratio is preferably added such that the _{HF / CF 3 CH 2 F =} 0.3 or more. When the amount of the hydrogen fluoride added is increased, the reaction of adding hydrogen fluoride to the unsaturated compound may be easily progressed to decrease the reaction temperature. This has the great advantage of inhibiting the production of by-products, reducing the loss of the desired product and extending the life of the catalyst. Further, when the crude product is CF ₃ CHF ₂ , the molar ratio of the azeotropic mixture of CF ₃ CHF ₂ and hydrogen fluoride is HF / CF ₃ CHF = about 0.1, thus, the newly added hydrogen fluoride is HF / CF ₃ CHF ₂ It is preferable to add in an amount which is a molar ratio with CF ₃ CHF _{2 of} = 0.2 or more. In the process of the present invention, the step of contacting the mixture obtained by newly adding hydrogen fluoride to the crude product with the fluorination catalyst in the gas phase is carried out by mixing hydrogen fluoride with the CF ₃ CH ₂ F and CF ₃ CHF ₂ alone and the mixture. May be brought into contact with the fluorination catalyst, or a mixture with hydrogen fluoride may be formed in a state where two compounds are mixed, and the mixture may be brought into contact with the fluorination catalyst. The method of contacting the mixture with the fluorination catalyst in the state where two compounds are mixed, followed by distillation and separation of them is preferred. In addition, as a method of supplying newly added hydrogen fluoride, any one of a batch supply system and a split supply system can be selected.

The fluorination catalyst used in the method of the present invention may be any one having a catalytic action against the fluorination reaction. Group IB, IIA of the periodic table containing at least one element selected from the group consisting of Cu, Mg, Zn, Pb, V, Bi, Cr, In, Mn, Fe, Co, Ni and Al as the catalyst Fluorinated catalysts composed of Groups II, IIB, IVB, VA, VB, VIA, VIIA and VIII, such as bulk catalysts containing mainly trivalent chromium oxide, or alumina, aluminum fluoride or activated carbon as carrier The supported catalyst used can be selected. As a method for producing the fluorination catalyst, a general method may be applied. It can be produced, for example, by impregnating an aqueous cobalt chloride solution with alumina, drying and firing it under an air stream. The catalyst thus prepared is preferably activated with nitrogen and / or hydrogen fluoride before it is used for the reaction.

It is preferable that it is in the range of 130-280 degreeC, and, as for the temperature which makes the said crude product and a fluorination catalyst contact, it is more preferable to exist in the range of 130-200 degreeC. When the said temperature is less than 130 degreeC, the reaction rate of the said unsaturated compound may become slow, whereas at the temperature over 280 degreeC, the tendency of the ratio of the above-mentioned side reaction to increase is seen.

The content of hydrogen chloride contained as impurities in the crude product is preferably 2 mol% or less. When the content of hydrogen chloride exceeds 2 mol%, impurities tend to increase.

After contacting the crude product and the fluorination catalyst, it is preferable that at least a portion of the hydrogen fluoride and the newly added hydrogen fluoride of the azeotropic component are separated in a distillation process, and the separated hydrogen fluoride is recycled to the obtained crude product. Do. The CF ₃ CH ₂ F can be separated and purified by distillation so that high purity CF ₃ CH ₂ F containing little unsaturated compound and chlorine-containing compound can be obtained in high yield. The total content of the chlorine-containing compound can be reduced to 2 ppm by volume or less.

The content of impurities contained in the CF ₃ CH ₂ F may be measured by TCD method or FID method of gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) method and the like.

Furthermore, pentafluoroethane and / or hexafluoroethane can be prepared by reacting such high purity 1,1,1,2-tetrafluoroethane and fluorine gas in the presence of a diluent gas. According to the production method of the present invention, as a material for producing the pentafluoroethane and hexafluoroethane, the total amount of the chlorine-containing compound containing 1,1,1,2-tetrafluoroethane as an impurity is very high. As such, high purity pentafluoroethane and hexafluoroethane can be produced. For example, the pentafluoroethane may provide a purity of at least 99.9998% by volume.

Next, the use of the high purity pentafluoroethane and hexafluoroethane obtained using the said manufacturing method is demonstrated. The high purity pentafluoroethane is, for example, mixed with an inert gas such as He, N ₂ or Ar and a gas such as O ₂ or NF ₃ (hereinafter sometimes referred to as a "pentafluoroethane product"), It may be used as an etching gas of an etching step in the semiconductor device manufacturing method. In addition, the high purity hexafluoroethane may be used as the cleaning gas in the semiconductor device manufacturing process.

Hereinafter, the present invention will be described in more detail with examples and comparative examples, but the present invention is not limited to these examples.

Preparation example of crude 1,1,1,2-tetrafluoroethane (raw material example 1)

Trichloroethylene (CCl ₂ = CHCl) as a starting material is reacted with hydrogen fluoride in the gas phase in the presence of a chromium-based fluorination catalyst to obtain an intermediate of mainly CF ₃ CH ₂ Cl, which is filled with other chromium-based fluorination catalysts. Two process reactions were carried out which were introduced into the reactor and further reacted with hydrogen fluoride. The crude 1,1,1,2-tetrafluoroethane obtained after the crude purification process was analyzed and had the following composition:

CF ₃ CH ₂ F 81.2080 CHCl = CHF 0.0020

CF ₃ CH ₂ Cl 6.2 400 CF ₃ CH ₃ 0.5630

CF ₃ CHF ₂ 0.5 320 CF ₃ CHClF 0.5310

CHF ₂ CHF ₂ 0.1600 CF ₃ CClF ₂ 0.0540

CF ₂ = CHCl 0.6420 HF (hydrogen fluoride) 9.5060

Hydrogen Chloride (HCl) 0.5620

                                                 Unit: volume%

Preparation example of crude pentafluoroethane (raw material example 2)

Tetrachloroethylene (CCl ₂ = CCl ₂ ) as a starting material was reacted with hydrogen fluoride in the gas phase in the presence of a chromium-based catalyst to obtain CF ₃ CHCl ₂ and CF ₃ CHClF mainly as intermediates, which were filled with a chromium-based fluorination catalyst. Two process reactions were carried out which were introduced into another reactor and reacted with hydrogen fluoride. The crude pentafluuroethane obtained after the crude purification process was analyzed and had the following composition:

CF ₃ CHF ₂ 86.9712 CF ₃ CHClF 3.8204

CF ₃ CHCl ₂ 0.0051 CF ₃ CClF ₂ 0.3121

CF ₃ CH ₃ 0.0161 CH ₂ F ₂ 0.0121

CF ₂ = CClF 0.0241 CF ₂ = CHF 0.0012

HF 8.3276 HCl 0.4820

Other 0.0281

                                   Unit: volume%

Catalyst Preparation Example 1 (Catalyst Example 1)

0.6 liters of pure water was charged to a 10 liter vessel and stirred. Obtained by dissolving 452 g of Cr (NO ₃ ) ₃ · 9H ₂ O and 42 g of In (NO ₃ ) ₃ · nH ₂ O (n is approximately 5) in 1.2 liters of pure water and 0.31 liters of 28% ammonia water. The solution was dripped in the said container over about 1 hour, adjusting the flow volume of the said 2 aqueous solution so that pH of the said reaction liquid might be in the range of 7.5-8.5. After the resulting slurry was filtered, the solid filtered off with pure water was washed well and dried at 120 ° C. over 12 hours. The dried solid was pulverized, mixed with graphite, and molded into a tablet molding machine to prepare pellets. The pellet was calcined at 400 ° C. for 4 hours under a flow of nitrogen gas to obtain a catalyst precursor. Next, a catalyst was prepared by filling the catalyst precursor in an Inconel reactor where hydrogen fluoride was used for fluorination (activation of the catalyst) at 350 ° C.

Catalyst Preparation Example 2 (Catalyst Example 2)

After 132 ml of pure water was charged with 191.5 g of chromium chloride (CrCl ₃ · 6H ₂ O), the chromium chloride was dissolved by heating to 70-80 ° C. in a bath. After the solution was cooled to room temperature, 400 g of activated alumina (NST-7 manufactured by Nikki Universal Co., Ltd.) was immersed to absorb the entire amount of the catalyst solution. The wet alumina was then dried in a 90 ° C. bath by the catalyst solution and dried to a solid. The solidified catalyst was dried at 110 ° C. for 3 hours by an air circulation hot air dryer, and after the drying catalyst was filled in a container made of SUS, the temperature was raised to 400 ° C. under circulation of air to prepare a catalyst precursor. Fluorination of the catalyst (activation of the catalyst) was carried out under the same procedure and under the same conditions as in Preparation Example 1 to produce a catalyst.

Catalyst Preparation Example 3 (Catalyst Example 3)

A catalyst was prepared in the same manner as in Catalyst Preparation Example 2, except that 16.6 g of zinc chloride (ZnCl ₂ ) was added as the second component to Catalyst Example 2.

Comparative example

80 ml of the catalyst obtained in Preparation Example 1 (Catalyst Example 1) were charged to an Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m. The temperature of the reactor was maintained at 180 ° C. under the flow of nitrogen gas, and after the crude 1,1,1,2-tetrafluoroethane (raw material example 1) was introduced into the reactor, the supply of nitrogen gas was stopped. Only the crude 1,1,1,2-tetrafluoro ethane was fed to the catalyst at 72 NL / hr. After about 4 hours, the gas was analyzed using gas chromatography after the acid component was removed by aqueous alkali solution. The gas has the following composition:

CF ₃ CH ₂ F 90.2993 CHCl = CHF 0.0003

CF ₃ CH ₂ Cl 7.6247 CF ₃ CH ₃ 0.6260

CF ₃ CHF ₂ 0.5916 CF ₃ CHClF 0.5904

CHF ₂ CHF ₂ 0.1779 CF ₃ CClF ₂ 0.0601

CF ₂ = CHC 1 0.0278 CH ₂ ClCHF ₂ 0.0019

                                               Unit: volume%

As is clear from the analysis, the conversion rate of the unsaturated compounds in the 1,1,1,2-tetrafluoroethane was about 95.8%, which proved that they could not be completely removed.

Next, the reaction was continued under the above conditions. After 2400 hours, the composition of the exhaust gas was analyzed. As a result, it was confirmed that the content of CF ₂ = CHCl was increased. The conversion of the unsaturated compound was reduced to about 93%. The reaction was stopped at this point, the catalyst was extracted, and the surface was observed to confirm the deposition of carbon (black) on the catalyst surface.

Example 1

An Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m was filled with 80 ml of the catalyst obtained in the catalyst preparation example (catalyst example 1) in the same manner as the comparative example, and the temperature in the reactor was changed to 180 while passing nitrogen gas. After the hydrogen fluoride was supplied at 10 Nl / hr from the inlet of the reactor, and crude 1,1,1,2-tetrafluoroethane (raw material example 1) was fed at 72 Nl / hr, Injection of nitrogen gas was stopped. After 4 hours, the gas was analyzed by gas chromatography after the acid component was removed by aqueous alkali solution. This had the following composition.

CF ₃ CH ₂ F 90.2998 CHCl = CHF <0.0001

CF ₃ CH ₂ Cl 7.6524 CF ₃ CH ₃ 0.6259

CF ₃ CHF ₂ 0.5 918 CF ₃ CHClF 0.5902

CHF ₂ CHF ₂ 0.1777 CF ₃ CClF ₂ 0.0600

CF ₂ = CHCl <0.0001 CH ₂ ClCHF ₂ 0.0020

                                   Unit: volume%

As apparent from the analysis results, the conversion rate of the unsaturated compound was about 99.9% by newly adding hydrogen fluoride to the crude 1,1,1,2-tetrafluoroethane.

Next, the gas from which the acid component was removed by the alkaline aqueous solution was recovered while cooling the cylinder, and distilled to cut the low boiling point portion, and the high boiling point portion was cut to obtain high-purity 1,1,1,2-tetrafluoroethane. Obtained. The purity was analyzed by gas chromatography (TCD method or FID method) and gas chromatography mass spectrometer (GC-MS method). It has the following composition:

CF ₃ CH ₂ F 99.9956 CHF ₂ CHF ₂ 0.0042

Chlorine-containing compound <0.0002

                                             Unit: volume%

As apparent from the above results, the chlorine-containing compound was contained in an amount of 2 vol ppm or less in the 1,1,1,2-tetrafluoroethane. When combined with the isomer 1,1,2,2-tetrafluoroethane, the purity is at least about 99.999% by volume.

In addition, purifying reaction of the crude 1,1,1,2-tetrafluoroethane was continued under the same conditions as above, and after analyzing the composition of the exhaust gas after 2400 hours, CF ₂ = CHCl No increase was confirmed. The conversion of the unsaturated compound was also maintained at about 99% or more.

In the same manner as in Comparative Example, the reaction was stopped at this point, and when the surface was observed by removing the catalyst, no deposition of carbon was confirmed. The catalyst was then charged back to the reactor and the reaction continued for 2000 hours under the same conditions, but the conversion of the unsaturated compound was maintained above about 99%.

Example 2

Nitrogen gas was supplied at 30 NL / hr by an Inconel 600 reactor having an inner diameter of 20.6 mm and a length of 500 mm (electric heater heating method: passivation completed at a temperature of 500 ° C. with fluorine gas) and the temperature was raised to 280 ° C. Then, as the diluent gas, the hydrogen fluoride was supplied at 50 NL / hr, and 1.8 N / hr to one of the gas streams of the dilution gas branched with 1,1,1,2-tetrafluoroethane obtained in Example 1 Was supplied. Thereafter, fluorine gas was supplied at 2.7 NL / hr to another gas stream of the diluting gas branched in the same manner as above, and the reaction was performed. After 3 hours, the reaction gas was analyzed by gas chromatography after hydrogen fluoride and fluorine gas were removed by an aqueous potassium hydroxide solution and an aqueous potassium iodide solution. The gas composition is as follows:

CF ₄ 0.4870 CF ₃ CF ₃ 49.6001

CF ₃ CHF ₂ 49.9 126 CF ₃ CH ₂ F <0.0001

Chlorine-containing compound <0.0002

                                             Unit: volume%

Next, as the cylinder was cooled, a gas from which hydrogen fluoride and fluorine gas had been removed was recovered and distilled to separate CF ₃ CF ₃ and CF ₃ CHF ₂ . After their low boiling point portion and high boiling point portion were cut, the results were analyzed by gas chromatography and GC-MS. The purity of the CF ₃ CF ₃ was greater than 99.9999 volume% and the purity of the CF ₃ CHF ₂ was 99.9998 volume%, thus high purity product could be obtained.

Example 3

An Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m was filled with 80 ml of catalyst obtained in Catalyst Preparation Example 2 (Catalyst Example 2). While supplying nitrogen gas, the temperature in the reactor was maintained at 180 ° C., hydrogen fluoride was supplied at 10 NL / hr from the inlet of the reactor, and then crude pentafluoroethane (raw material example 2) was supplied to the reactor at 72 NL / hr. After that, the supply of nitrogen gas was stopped. After 4 hours, the exhaust gas was analyzed using gas chromatography after the acid component was removed by alkaline aqueous solution. This had the following composition.

CF ₃ CHF ₂ 95.3 734 CF ₃ CHClF 4.2156

CF ₃ CHCl ₂ 0.0056 CF ₃ CClF ₂ 0.3422

CF ₃ CH ₃ 0.0176 CH ₂ F ₂ 0.0133

CF ₂ = CClF ₂ <0.0002 CF ₂ = CHF <0.0001

CF ₃ CH ₂ F 0.0012 Other 0.0308

                                      Unit: volume%

As is apparent from the above results, about 99% of the unsaturated compounds in the crude pentafluoroethane could be removed (converted).

Example 4

An Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m was filled with 80 ml of catalyst obtained in Catalyst Preparation Example 3 (Catalyst Example 3). While supplying nitrogen gas, the temperature in the reactor was maintained at 180 ° C., and hydrogen fluoride was supplied at 10 NL / hr from the inlet of the reactor, followed by 36 N / hr of crude 1,1,1,2-tetrafluoroethane ( Raw material example 1) and 3 NL / hr of jofentafluoroethane (raw material example 2) were mixed at the inlet of the reactor and fed to the reactor. Then, the injection of nitrogen gas was stopped. After 4 hours, the gas was analyzed by gas chromatography after the acid component was removed by aqueous alkali solution. About 99% of the unsaturated compounds contained could be removed (converted).

The present invention is useful for the production of 1,1,1,2-tetrafluoroethane and pentafluoroethane which can advantageously be used as low temperature refrigerants, etching gases and cleaning gases.

Claims (13)

Main product comprising 1,1,1,2-tetrafluoroethane, hydrogen fluoride and at least 1,1-difluoro-2-chloroethylene, 1,2-difluoro as azeotropic components with said main product Hydrogen fluoride and trichloroethylene comprising an impurity component comprising at least one compound selected from the group consisting of -1-chloroethylene, 1-chloro-2-fluoroethylene and 1,1,2-trifluoroethylene In the method for producing 1,1,1,2-tetrafluoroethane by the step of purifying the crude product obtained by the reaction, the purification step is a gaseous mixture of the mixture obtained by hydrogen fluoride newly added to the crude product 1,1-difluoro-2-chloroethylene, 1,2-difluoro-1-chloroethylene, 1-chloro-2-fluoroethylene and 1,1 contained in the crude product by contact with a fluorination catalyst Consisting of 2-trifluoroethylene The process for producing 1,1,1,2-tetrafluoroethane, comprising the step of reducing the content of at least one compound selected from the group and a distillation process. The method for producing 1,1,1,2-tetrafluoroethane according to claim 1, wherein the content of hydrogen chloride contained as impurities in the crude product is 2 mol% or less. 3. The 1,1,1,2 according to claim 1 or 2, wherein the concentration of 1,1,1,2-tetrafluoroethane contained in the crude product is 70 mol% or more and less than 100 mol%. Method for preparing tetrafluoroethane. delete The method of claim 1 or 2, wherein the fluorination catalyst comprises at least one metal element selected from the group consisting of Cu, Mg, Zn, Pb, V, Bi, Cr, In, Mn, Fe, Co, Ni and Al. Method for producing 1,1,1,2-tetrafluoroethane, characterized in that it comprises. The method for producing 1,1,1,2-tetrafluoroethane according to claim 1 or 2, wherein the contact temperature between the mixture and the fluorination catalyst is in the range of 130 to 280 ° C. delete The method for producing 1,1,1,2-tetrafluoroethane according to claim 1, wherein the contact temperature between the mixture and the fluorination catalyst is in the range of 130 to 200 ° C. The method of claim 1 or 2, further comprising the step of separating the hydrogen fluoride in the distillation step and recycling the separated hydrogen fluoride in the step of obtaining the crude product. Method for the preparation of 2-tetrafluoroethane. delete Main product comprising 1,1,1,2-tetrafluoroethane, hydrogen fluoride and at least 1,1-difluoro-2-chloroethylene, 1,2-difluoro as an azeotropic component with the main product Hydrogen fluoride and trichloroethylene comprising an impurity component comprising at least one compound selected from the group consisting of -1-chloroethylene, 1-chloro-2-fluoroethylene and 1,1,2-trifluoroethylene To the crude product obtained by the reaction, a mixture obtained by newly adding hydrogen fluoride is brought into contact with a fluorination catalyst in a gaseous phase, thereby to obtain 1,1-difluoro-2-chloroethylene and 1,2-difluoro- contained in the crude product. 1,1, including a process for reducing the content of at least one compound selected from the group consisting of 1-chloroethylene, 1-chloro-2-fluoroethylene and 1,1,2-trifluoroethylene and a distillation process 1,2-tetrafluoro To afford a; And A method for producing at least one of pentafluoroethane and hexafluoroethane, comprising reacting 1,1,1,2-tetrafluoroethane and fluorine gas obtained in the step in the presence of a diluent gas. delete delete