KR100643674B1 - Process for production of hydrofluorocarbons, products thereof and use of the products - Google Patents

Abstract

The methane halide mixture and the hydrogen fluoride are reacted in a gaseous phase in the presence of a fluorination catalyst in a single reaction zone, and the product gas is led to a distillation column for separation and purification, thereby obtaining two or more hydrofluorocarbons. High purity hydrofluorocarbons, in particular fluoromethane and difluoromethane, which can be used as an etching gas or a cleaning gas in the manufacturing process of a semiconductor device, can be industrially advantageously produced.

Description

Process for producing hydrofluorocarbons, products thereof and uses thereof {PROCESS FOR PRODUCTION OF HYDROFLUOROCARBONS, PRODUCTS THEREOF AND USE OF THE PRODUCTS}

The present invention relates to a method for producing high purity hydrofluorocarbon, a product thereof, and a use thereof.

Hydrofluorocarbons (hereinafter may be referred to as "HFC") have the characteristic of having an ozone depletion coefficient of zero, for example, mainly 1,1,1,2-tetrafluoroethane and pentafluoroethane. Ina difluoromethane (hereinafter may be referred to as "HFC-32") is a compound useful as a refrigerant gas, and fluoromethane (hereinafter may be referred to as "HFC-41"), difluoromethane Or trifluoromethane (hereinafter sometimes referred to as "HFC-23") is a compound useful as an etching gas for semiconductors.

As a method for producing difluoromethane, for example, methylene chloride (hereinafter may be referred to as "dichloromethane") or chlorofluoromethane (hereinafter may be referred to as "HCFC-31") and hydrogen fluoride. And a method of reacting in a gas phase in the presence of a fluorination catalyst (US Patent No. 2745886, US Patent No. 3235612) and the like are known, and a method of using antimony halide as a catalyst by liquid phase method (US Patent No. 2005711) Although these etc. are also known, all are proposals regarding a catalyst mainly.

As a method for producing fluoromethane, for example, a method of fluorinating methyl alcohol and hydrogen fluoride using a chromium fluoride catalyst in the gas phase (Japanese Patent Laid-Open No. Hei 4-7330), or chromium chloride and hydrogen fluoride Although a method of reacting in the gas phase in the presence of a catalyst (Japanese Patent Laid-Open No. 60-13726) and the like are known, there are problems such as corrosion due to generated water and poor selectivity.

As a method for producing two or more kinds of hydrofluorocarbons, for example, 2-chloro-1,1,1-trifluoroethane and hydrogen fluoride are reacted to generate 1,1,1,2-tetrafluoroethane. In the presence of 1,1,1,2-tetrafluoroethane, methyl chloride and trichloroethylene are reacted with hydrogen fluoride (WO95 / 15937) or trichloroethylene and hydrogen fluoride are reacted to give 2- Chloro-1,1,1-trifluoroethane is produced, followed by reaction of 2-chloro-1,1,1-trifluoroethane with hydrogen fluoride to form 1,1,1,2-tetrafluoroethane. During the production process, for example, 2,2-dichloro-1,1,1-trifluoroethane or 2-chloro-1,1,1,2-tetrafluoroethane may be added to add 1,1,1, A method for producing pentafluoroethane with 2-tetrafluoroethane (Japanese Patent Laid-Open No. 7-507787) and the like are known, but any It has two reaction zones (1st reactor and 2nd reactor) different from reaction conditions, and there exists a problem of being uneconomical, and the subject remains.

The present invention has been made under such a background, and the industrially advantageous method for producing high-purity hydrofluorocarbons, in particular fluoromethane and difluoromethane, which can be used as etching gas or cleaning gas in the manufacturing process of semiconductor devices. The object of this invention is to provide the product and its use.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, as a raw material, it uses the halogenated methane halide mixture and hydrogen fluoride as a raw material, and makes them react in a gaseous phase in presence of a fluorination catalyst, in a single reaction zone (one reactor), Using a method comprising a step of guiding gas to a distillation column to separate and purify and then obtaining two or more hydrofluorocarbons, the inventors have found that the above problems can be solved, and have completed the present invention.

Accordingly, the present invention provides a process for obtaining two or more hydrofluorocarbons by reacting a methane halide mixture and hydrogen fluoride in a single reaction zone in the presence of a fluorination catalyst in a gas phase, and then separating and purifying the product gas through a distillation column. It provides a method for producing a hydrofluorocarbon comprising the.

The present invention further provides a fluoromethane product obtained by using the above production method and containing fluoromethane having a purity of 99.999 vol% or more, or containing difluoromethane having a purity of 99.999 vol% or more. Provided is a difluoromethane product.

The present invention also provides an etching gas or a cleaning gas comprising the above fluoromethane product or difluoromethane product.

That is, this invention includes the matter shown to the following [1]-[19], for example.

[1] a process of obtaining a mixture of methane halides and hydrogen fluoride in a gaseous phase in a single reaction zone in the presence of a fluorination catalyst, separating and purifying the product gas by distillation column, and then obtaining two or more hydrofluorocarbons. Method for producing a hydrofluorocarbon, characterized in that.

[2] The above-mentioned [1], wherein the halogenated methane mixture of the raw material is composed of two or more compounds selected from the group consisting of methyl chloride, methylene chloride, chloroform, dichlorofluoromethane, chlorofluoromethane and chlorodifluoromethane. Process for producing the hydrofluorocarbons described.

[3] The method for producing a hydrofluorocarbon according to the above [1] or [2], wherein the halogenated methane mixture is made of methyl chloride and methylene chloride.

[4] The hydrofluoro according to any one of the above [1] to [3], wherein the obtained hydrofluorocarbon is at least two compounds selected from the group consisting of fluoromethane, difluoromethane and trifluoromethane. Method of producing carbon.

[5] The method for producing a hydrofluorocarbon according to any one of [1] to [4], wherein the obtained hydrofluorocarbons are fluoromethane and difluoromethane.

[6] The method for producing hydrofluorocarbons according to any one of [1] to [5], wherein the concentration of one halogenated methane contained in the halogenated methane mixture is in the range of 5 to 95 mass%.

[7] The method for producing a hydrofluorocarbon according to the above [6], wherein the concentration of one halogenated methane contained in the halogenated methane mixture is in the range of 10 to 90 mass%.

[8] The method for producing a hydrofluorocarbon according to any one of [1] to [7], wherein the reaction is performed in a molar ratio of hydrogen fluoride and methane halide as a reaction raw material within a range of 5 to 30.

[9] The method for producing a hydrofluorocarbon according to any one of [1] to [8], wherein the reaction is performed within a temperature range of 150 to 350 ° C.

[10] The method for producing a hydrofluorocarbon according to any one of [1] to [9], wherein the reaction is performed within a pressure range of 0.05 to 1 MPa.

[11] The method for producing hydrofluorocarbons according to any one of [1] to [10], wherein the fluorinated catalyst is a supported or bulk catalyst having a trivalent chromium oxide as a main component.

[12] The above-mentioned gas which introduces a product gas reacted in a single reactor into a first distillation column, separates hydrogen chloride and hydrofluorocarbon mainly from the top of the column, and separates hydrogen fluoride and unreacted halogenated methane halide from the bottom of the column. The manufacturing method of the hydrofluorocarbon in any one of 1]-[11].

[13] Hydrogen chloride and hydrofluorocarbons separated from the top of the first distillation column are introduced into the second distillation column, hydrogen chloride is separated mainly from the top of the column, and hydrofluorocarbons are separated from the bottom of the column. The manufacturing method of the hydrofluorocarbon in any one of said [1]-[12] which isolate | separates and refine | purifies a carboxyl carbon and collect | recovers as a product.

[14] The production of hydrofluorocarbons according to any one of [1] to [13], wherein mainly hydrogen fluoride and unreacted halogenated methane separated from the bottom of the column of the first distillation column are circulated to a single reaction zone as a reaction step. Way.

[15] The method for producing a hydrofluorocarbon according to any one of [1] to [14], wherein the operating pressures of the first distillation column and the second distillation column are in the range of 0.3 to 3 MPa.

[16] A fluoromethane product obtained by using the production method according to any one of [1] to [15] and containing fluoromethane having a purity of 99.999 vol% or more.

[17] A difluoromethane product obtained by using the production method according to any one of [1] to [15] and containing difluoromethane having a purity of 99.999 vol% or more.

[18] An etching gas or cleaning gas containing the fluoromethane product according to the above [16].

[19] An etching gas or cleaning gas containing the difluoromethane product according to the above [17].

According to the present invention, it can be used as an etching gas or a cleaning gas in the manufacturing process of a semiconductor device, and industrially advantageously, high-purity hydrofluorocarbons, especially fluoromethane and difluoromethane, can be produced.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the apparatus used for the manufacturing method of the hydrofluorocarbon of this invention.

EMBODIMENT OF THE INVENTION Below, the manufacturing method of the hydrofluorocarbon of this invention, its product, and its use are demonstrated in detail.

As the method for producing fluoromethane, various methods are known in the art as described above. Among them, (1) a method of fluorinating methyl alcohol and hydrogen fluoride in the presence of a fluorination catalyst in the gas phase, and (2) a method of reacting methyl chloride and hydrogen fluoride in the gas phase in the presence of a chromium fluoride catalyst, The method of using the methyl alcohol of 1) has problems such as corrosion of the device material by the generated water and poor selectivity, and the method of using the methyl chloride of (2) has an equilibrium in the reaction and yield. This has a low back problem. On the other hand, as a method for producing difluoromethane, (3) a method of reacting methylene chloride or chlorofluoromethane with hydrogen fluoride in a gaseous phase or in a liquid phase is known, but it remains a problem as an economical and inexpensive production method.

Moreover, as a manufacturing method of 2 or more types of hydrofluorocarbons, methyl chloride and trichloroethylene are added and it reacts in the process of manufacturing 1,1,1,2- tetrafluoroethane in two reactors as mentioned above. Although the method of making it etc. is known, either has two reaction zones (1st reactor and 2nd reactor) different from reaction conditions, and remains a problem as an economical and inexpensive manufacturing method.

EMBODIMENT OF THE INVENTION Below, the preferable aspect of the manufacturing method of the hydrofluorocarbon of this invention is demonstrated in detail.

In the method for producing a hydrofluorocarbon of the present invention, a methane halide mixture and hydrogen fluoride are used as raw materials, and these are reacted in a single reaction zone (one reactor) in the presence of a fluorination catalyst in the gas phase to guide the generated gas to the distillation column. After separation and purification, a step of obtaining two or more hydrofluorocarbons is characterized. The halogenated methane mixture of the raw material is preferably methyl chloride (CH ₃ Cl), methylene chloride (CH ₂ Cl ₂ ), chloroform (CHCl ₃ ), dichlorofluoromethane (CHCl ₂ F), chlorofluoromethane (CH ₂ It consists of at least two compounds selected from the group consisting of ClF) and chlorodifluoromethane (CHClF ₂ ), more preferably one consisting of methyl chloride and methylene chloride. As these supply methods, either a method of supplying each independently and mixing at the inlet of the reactor or the method of supplying in a mixed state from the beginning can be selected. In addition, it is preferable that the methane halide mixture is water-repellent or stabilizer removed using a dehydrating agent such as Molecular Sieves in the previous step of feeding the reactor.

The concentration of one halide methane contained in the halogenated methane mixture is preferably in the range of 5 to 95 mass%, more preferably in the range of 10 to 90 mass%, and in this concentration range, for example, The advantage of being able to adjust arbitrarily can be obtained. Starting methane halides and hydrogen fluoride are mixed at the reactor inlet. The molar ratio (supply ratio) of hydrogen fluoride and methane halide is preferably 5 to 30, and when it is less than 5, the generation ratio of impurities is large, and the selectivity may deteriorate. Moreover, when it exceeds 30, a yield may fall, or the circulation amount of an unreacted raw material or an intermediate may increase, and an apparatus may become large and it is unpreferable. The methane halide mixture and hydrogen fluoride of the raw materials are mixed at the reactor inlet, heated in a preheater, and then introduced into a single reaction zone (reactor). The reactor is preferably multi-tubular in view of anti-drift. The fluorinated catalyst charged in the reactor is preferably a supported or bulk catalyst having trivalent chromium oxide as a main component. As a carrier of the supported catalyst, alumina, alumina fluoride, activated carbon and the like are preferable. In addition to trivalent chromium oxide, a small amount of additive metal may be contained, and indium, nickel, zinc and / or cobalt are preferable as the additive metal. These fluorination catalysts are preferably those at least partially fluorinated with, for example, hydrogen fluoride at a previous stage of the reaction. 150-350 degreeC is preferable and, as for the temperature range of reaction, 200-300 degreeC is more preferable. If it is less than 150 degreeC, reaction yield falls and it is unpreferable, and when it exceeds 350 degreeC, undesirable impurity may increase. The pressure range of the reaction is preferably 0.05 to 1.0 MPa, more preferably 0.1 to 0.7 MPa. When it is less than 0.05 MPa, operation is difficult, and when it exceeds 1.0 MPa, it is not economical, for example, it must be made into a pressure resistant structure. At least a part of the product (outlet) gas reacted in the reactor is cooled, for example, introduced into the first distillation column by a pump, or introduced into the first distillation column by using a compressor. The operating pressure of the first distillation column is preferably 0.3 to 3 MPa from the viewpoint of economical efficiency and operability. In the distillation method (a), the product gas introduced into the first distillation column is mainly separated from hydrogen chloride and hydrofluorocarbon from the top of the column, guided to the second distillation column, and mainly unreacted fluoride from the bottom of the column of the first distillation column. Hydrogen and unreacted halide methane are separated and used for circulation in a single reaction zone, the reaction process. Hydrogen chloride and hydrofluorocarbon mainly introduced into the second distillation column are mainly used to separate hydrogen chloride from the top of the column in a pressure range of 0.3 to 3 MPa, and to use hydrogen chloride separately by, for example, absorbing it into water. . At least some of the hydrofluorocarbons contained in the hydrogen chloride are recovered and reused. Hydrofluorocarbons are mainly separated from the bottom of the column of the second distillation column, and these are introduced into the third distillation column to separate low boiling point, for example, fluoromethane, from the column top in the pressure range of 0.3 to 3 MPa, It is purified in the purification step and recovered as a product. In addition, a high boiling point, for example, difluoromethane is separated from the bottom of the column and purified in a purification process to be recovered as a product. In the distillation method (b), the product gas introduced into the first distillation column is mainly separated from hydrogen chloride from the top of the column, and recovered and reused as in (a). Mainly unreacted hydrogen fluoride, unreacted methane halides, and hydrofluorocarbons are separated from the bottom of the column, and these are introduced into a second distillation column, and in the second distillation column, mainly hydrofluorocarbons are separated from the top of the column. Is introduced. The unreacted hydrogen fluoride and the unreacted methane halide are mainly separated from the bottom of the column of the second distillation column, and these are circulated in the reaction process as in (a) and used. The mainly hydrofluorocarbons introduced into the third distillation column are separated from the column top with low boiling point, for example, fluoromethane, and purified in a purification step to be recovered as a product. Further, for example, difluoromethane, which has a higher boiling point than the bottom of the column, is separated and purified in a purification process and recovered as a product.

Both distillation methods (a) and (b) are purified both at low boiling point separated from the top of the third distillation column, for example fluoromethane, and at higher boiling point separated from the bottom of the column, for example difluoromethane. In the process, it is submitted to an inert (oxygen, nitrogen, etc.) cut, an adsorption treatment with an adsorbent (molecular and / or activated carbon), or the like, whereby a high purity product having a purity of 99.999 vol% or more can be obtained. For example, fluoromethane or difluoromethane having a purity of 99.999 vol% or more is TCD method of gas chromatograph (GC), FID method (all including precut method), ECD method or gas chromatograph mass spectrometer ( Analysis using an analyzer such as GC-MS).

Next, the use of the hydrofluorocarbons obtained using the production method of the present invention, in particular fluoromethane and difluoromethane, will be described. High-purity fluoromethane, difluoromethane, or a mixed gas with an inert gas such as He, N ₂ , Ar, O ₂ , NF ₃ or the like (in this specification, "fluoromethane product", " Difluoromethane product ”) can be used as an etching gas in an etching step in a semiconductor device manufacturing step or as a cleaning gas in a semiconductor device manufacturing step. The etching method can be carried out under various dry etching conditions such as plasma etching, microwave etching, etc., and is suitable for inert gas such as He, N ₂ , Ar, or gas such as HCl, O ₂ , H ₂ , F ₂ , NF ₃ and the like. You may mix and use in ratio.

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited only to these Examples.

Example 1

Preparation of Catalysts Example 1

Into a 10 L vessel, add 0.6 L of pure water and stir, and in this, 1.2 L of pure water 452 g of Cr (NO ₃ ) ₃ · 9H ₂ O and 42 g of In (NO ₃ ) ₃ · nH ₂ O (n is about 5) The melted solution and 0.31 L of 28% ammonia water were dripped over about 1 hour, controlling the flow volume of 2 types of aqueous solution so that pH of a reaction liquid might be in the range of 7.5-8.5. The slurry thus obtained was filtered, and the filtered solid was washed well with pure water, followed by drying at 120 ° C for 12 hours. The dry solid was pulverized, mixed with graphite, and pellets were produced by a tablet molding machine. This pellet was baked at 400 degreeC for 4 hours under nitrogen stream, and it was set as the catalyst precursor. Next, the catalyst precursor was charged into an Inconel reactor, and first, fluorination treatment (activation of the catalyst) was performed at 350 ° C under normal pressure under a stream of nitrogen-dilute hydrogen fluoride. Subsequently, under a pressure of 0.3 MPa, a fluorination treatment (activation of a catalyst) was performed under a nitrogen-dilution hydrogen fluoride stream, followed by a 100% hydrogen fluoride stream, to prepare a catalyst.

Example 2

Preparation of Catalyst Example 2

191.5 g of chromium chloride (CrC1 ₃ · 6H ₂ O) was added to 132 ml of pure water, and the resulting mixture was heated and dissolved at 70 to 80 ° C. on a water bath. After cooling the solution to room temperature, 400 g of activated alumina (Nikiki Universal Co., Ltd. NST-7) was immersed, and the whole solution was absorbed in alumina.

Subsequently, the wet alumina was dried and dried on a 90 degreeC hot water bath. The dried catalyst was dried at 110 ° C. for 3 hours in an air circulation hot air dryer. The drying catalyst was filled in a container made of SUS, air was flowed at a space velocity (SV) of 540 Hr ⁻¹ , and calcined under flow. After calcining at 200 ° C until the heat generation of the catalyst layer disappeared, the temperature was further raised to 400 ° C and calcined for 3 hours to obtain a catalyst. The catalyst was charged in an Inconel reactor, first, at a normal pressure of 250 ° C., under a nitrogen-diluted hydrogen fluoride stream, and then gradually elevated in temperature to perform a fluorination treatment at 350 ° C., followed by a further nitrogen dilution fluorine at a pressure of 0.3 MPa. The catalyst was prepared by performing a fluorination treatment under a hydrogen stream and then under a 100% hydrogen fluoride stream.

Example 3

Preparation of Hydrofluorocarbons

100 ml of the catalyst obtained in Example 1 was filled into an Inconel 600 reactor having an inner diameter of 1 inch and a length of 1 m, and the reactor temperature was maintained at 300 ° C. and the pressure was 0.2 MPa while flowing nitrogen gas.

Next, hydrogen fluoride was supplied at a flow rate of 82 NL / hr, after which the supply of nitrogen gas was stopped. From one raw material inlet, methyl chloride (CH ₃ Cl) dehydrated with zeolite (molecular: 3 A) was supplied at ₃ NL / hr, and the zeolite (molecular: 3 A) was supplied from the other raw material inlet. Methylene chloride (CH ₂ Cl ₂ ), which had been dehydrated), was fed at 1 NL / hr to initiate a reaction. After 2 hours, the outlet gas from the reactor was washed with an aqueous potassium hydroxide solution to remove acid content, and the gas composition was analyzed by gas chromatography, and the composition (unit: vol%) was shown below.

CH ₃ F 13.3253 CH ₂ F ₂ 24.6 108

CH ₂ ClF 0.3720 CH ₂ Cl ₂ 0.0205

CH ₃ Cl 61.6557 Other 0.0157

Example 4

Method for preparing hydrofluorocarbon

In the same manner as in Example 3, 100 ml of the catalyst obtained in Example 1 was packed into an Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m, and the reactor temperature was maintained at 300 ° C. and the pressure was 0.2 MPa while flowing nitrogen gas.

Next, hydrogen fluoride was supplied at a flow rate of 82 NL / hr, after which the supply of nitrogen gas was stopped. Methyl chloride (CH ₃ Cl) dehydrated with zeolite (molecular: 3 A) was supplied at 2 NL / hr from one raw material inlet, and zeolite (molecular: 3 A) was supplied from another raw material inlet. The methylene chloride (CH ₂ Cl ₂ ) dehydrated with was fed at ₂ NL / hr to initiate a reaction. After 2 hours, the outlet gas from the reactor was washed with an aqueous potassium hydroxide solution to remove acid content, and the gas composition was analyzed by gas chromatography, and the composition (unit: vol%) was shown below.

CH ₃ F 8.8892 CH ₂ F ₂ 49.1216

CH ₂ ClF 0.7210 CH ₂ Cl ₂ 0.1374

CH ₃ Cl 41.0983 Other 0.0325

Example 5

Method for preparing hydrofluorocarbon

100 ml of the catalyst obtained in Example 1 was filled into an Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m, and the reactor temperature was maintained at 290 ° C and the pressure was 0.2 MPa while flowing nitrogen gas.

Next, hydrogen fluoride was supplied at a flow rate of 73.85 NL / hr, after which the supply of nitrogen gas was stopped. Methylene chloride (CH ₂ Cl ₂ ) dehydrated with zeolite (molecular: 3A) was supplied from one raw material inlet at ₂ NL / hr, and zeolite (molecular: 3 A) was supplied from the other raw material inlet. Chloroform (CHCl ₃ ) dehydrated with) was fed at 2 NL / hr to initiate the reaction. After 2 hours, the outlet gas from the reactor was washed with an aqueous potassium hydroxide solution to remove acid content, and the gas composition was analyzed by gas chromatography, and the composition (unit: vol%) was shown below.

CH ₂ F ₂ 47.6317 CHF ₃ 49.0118

CH ₂ ClF 1.7578 CHClF ₂ 0.8808

CHCl ₂ F 0.0631 CH ₂ Cl ₂ 0.5924

CHCl ₃ 0.0321 Other 0.0303

Example 6

Method for preparing hydrofluorocarbon

100 ml of the catalyst obtained in Example 2 was filled into an Inconel 600 reactor having an internal diameter of 1 inch and a length of 1 m, and the reactor temperature was maintained at 315 ° C and the pressure was 0.2 MPa while flowing nitrogen gas.

Next, hydrogen fluoride was supplied at a flow rate of 73.85 NL / hr, after which the supply of nitrogen gas was stopped. Methyl chloride (CH ₃ Cl) dehydrated with zeolite (molecular: 3 A) was supplied at 2 NL / hr from one raw material inlet, and zeolite (molecular: 3 A) was supplied from another raw material inlet. Chloroform (CHCl ₃ ) dehydrated with 2NL / hr was fed to initiate the reaction. After 2 hours, the outlet gas from the reactor was washed with an aqueous potassium hydroxide solution to remove acid content, and the gas composition was analyzed by gas chromatography, and the composition (unit: vol%) was shown below.

CH ₃ F 9.4 268 CHF ₃ 49.3833

CHClF ₂ 0.4712 CHCl ₂ F 0.1176

CH ₃ Cl 40.5561 CHCl ₃ 0.0108

Other 0.0342

Example 7

High purity CH ₃ F product

Using the apparatus shown in FIG. 1, the reactor outlet gas obtained by the reaction in the same manner as in Example 3 was introduced into the first distillation column to separate hydrogen chloride and hydrofluorocarbon from the top of the column, and then from the bottom of the top of the second distillation column. The separated hydrofluorocarbon was introduced into a third distillation column to perform fractionation purification. 1, 1 is a reactor (single reaction zone), 2 is a first distillation column, 3 is a second distillation column, 4 is a third distillation column, 5 is a fluoromethane purification step, 6 is a difluoromethane purification step. to be.

The column top distillation component of the 3rd distillation column 4 shown in FIG. 1 was analyzed with the TCD method, the FlD method, and the gas chromatograph mass spectrometer (GC-MS) of a gas chromatograph (GC), and the composition shown below ( Unit: vol%).

CH ₃ F 99.9984 CH ₄ 0.0005

CH ₂ = CH ₂ 0.0005 CO ₂ 0.0003

Other 0.0003

Zeolite (molecular 3A (manufactured by Union Showa Co., Ltd .: 3 mm average diameter) and Molecular 4A (manufactured by Union Showa Co., Ltd .: average pore diameter 3.5 mm)) in a 100 ml stainless steel cylinder 20 g of an equivalent mixture was charged, and after vacuum drying, about 50 g of the columnar distillate was charged while cooling the cylinder, and occasionally stirred while maintaining the temperature at -10 ° C. After about 5 hours, the liquid phase was gas chromatographed. As a result of analyzing by TCD method, FID method, and the gas chromatograph mass spectrometer of a graph, it was a composition (unit: vol%) shown below.

CH ₃ F 99.9993 CH ₄ <0.0001

CH ₂ = CH ₂ 0.0002 CO ₂ 0.0002

Other 0.0002

Example 8

High purity CH ₂ F ₂ product

The bottom distillation component of the third distillation column 4 of Example 7 was analyzed by TCD method, FID method and gas chromatograph mass spectrometer (GC-MS) of the gas chromatograph (GC). : vol%).

CH ₂ F ₂ 99.9986 CH ₃ Cl 0.0007

CH ₂ ClF 0.0005 Other 0.0002

A volume of 100 ml stainless steel cylinder was filled with 15 g of zeolite (molecular 3A) and 5 g of carbonaceous adsorbent (molecular sorbing carbon, manufactured by Takeda Yakuhing Kogyo Co., Ltd .: average pore diameter of 4 mm). After vacuum drying, the cylinder was cooled and filled with about 50 g of the above-mentioned bottom distillate, sometimes stirred while maintaining the temperature at -10 ° C, and after about 5 hours, the liquid phase was subjected to the TCD method or the FID method of the gas chromatograph. And gas chromatograph mass spectrometer, the composition (unit: vol%) shown below.

CH ₂ F ₂ 99.9996 CH ₃ Cl 0.0002

CH ₂ ClF 0.0001 Other 0.0001

INDUSTRIAL APPLICABILITY The present invention can be advantageously used for industrial production of high purity hydrofluorocarbons, in particular fluoromethane and difluoromethane, which can be used as an etching gas or a cleaning gas in the manufacturing process of a semiconductor device.

Claims (19)

And reacting the halogenated methane mixture and hydrogen fluoride in a single reaction zone in the presence of a fluorination catalyst in the gas phase, separating and purifying the product gas by distillation column, and then obtaining two or more hydrofluorocarbons. Method for producing a hydrofluorocarbon. The methane halide mixture of the raw material is composed of at least two compounds selected from the group consisting of methyl chloride, methylene chloride, chloroform, dichlorofluoromethane, chlorofluoromethane and chlorodifluoromethane. Method for producing a hydrofluorocarbon to be. The process for producing hydrofluorocarbons according to claim 1 or 2, wherein the halogenated methane mixture consists of methyl chloride and methylene chloride. The hydrofluorocarbon according to claim 1 or 2, wherein the obtained hydrofluorocarbon is at least two compounds selected from the group consisting of fluoromethane, difluoromethane and trifluoromethane. Manufacturing method. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein the obtained hydrofluorocarbons are fluoromethane and difluoromethane. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein the concentration of one halogenated methane contained in the halogenated methane mixture is in the range of 5 to 95% by mass. The method for producing a hydrofluorocarbon according to claim 6, wherein the concentration of one halogenated methane contained in the halogenated methane mixture is in the range of 10 to 90 mass%. The method for producing hydrofluorocarbons according to claim 1 or 2, wherein the reaction is carried out within a molar ratio of hydrogen fluoride and methane halide as a reaction raw material in the range of 5 to 30. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein the reaction is performed within a temperature range of 150 to 350 ° C. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein the reaction is performed within a pressure range of 0.05 to 1 MPa. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein the fluorinated catalyst is a supported or bulk catalyst having a trivalent chromium oxide as a main component. 3. The product gas according to claim 1 or 2, wherein the product gas reacted in a single reaction zone is introduced into the first distillation column, and mainly hydrogen chloride and hydrofluorocarbon are separated from the top of the column, and mainly hydrogen fluoride and unreacted from the bottom of the column. A method for producing a hydrofluorocarbon, characterized by separating a halogenated methane. The method according to claim 1 or 2, wherein mainly hydrogen chloride and hydrofluorocarbon separated from the top of the first distillation column are introduced into the second distillation column, and mainly hydrogen chloride is separated from the top of the column, and mainly hydrofluoro from the bottom of the column. A method for producing a hydrofluorocarbon, comprising separating carbon and separating and purifying the hydrofluorocarbon to recover as a product. The method for producing a hydrofluorocarbon according to claim 1 or 2, wherein mainly hydrogen fluoride and unreacted halogenated methane separated from the bottom of the column of the first distillation column are circulated in a single reaction zone as a reaction step. The process for producing a hydrofluorocarbon according to claim 1 or 2, wherein the operating pressures of the first distillation column and the second distillation column are in the range of 0.3 to 3 MPa. A fluoromethane product obtained by using the production method according to claim 1 or 2, containing fluoromethane having a purity of 99.999 vol% or more. A difluoromethane product obtained by using the production method according to claim 1 or 2, containing difluoromethane having a purity of 99.999 vol% or more. An etching gas or cleaning gas containing the fluoromethane product according to claim 16. An etching gas or cleaning gas containing the difluoromethane product according to claim 17.

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