Method for purifying octafluorocyclobutane, method for its preparing and applying

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for purifying octafluorocyclobutane. Method is carried out by interaction of crude octafluorocyclobutane containing impurities with the impurity-decomposing agent at increased temperature and then with adsorbent that is able to eliminate indicated impurities up to the content less 0.0001 wt.-% from the mentioned crude octafluorocyclobutane. Impurity-decomposing agent comprises ferric (III) oxide and compound of alkaline-earth metal in the amount from 5 to 40 wt.-% of ferric oxide and from 60 to 95 wt.-% of compound of alkaline-earth metal as measured for the complete mass of the impurity-decomposing agent. Ferric (III) oxide represents γ-form of iron hydroxyoxide and/or γ-form of ferric (III) oxide. Impurity represents at least one fluorocarbon taken among the group consisting of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,2,2,2-tetrafluoroethane, 1-chloro-1,1,2,2-tetrafluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, hexafluoropropene and 1H-heptafluoropropane. Adsorbent represents at least one of representatives taken among the group including activated carbon, carbon molecular sieves and activated coal. Crude octafluorocyclobutane interacts with the mentioned impurity-decomposing agent at temperature from 250oC to 380oC. Invention proposes gas, etching gas and purifying gas including octafluorocyclobutane with purity degree 99.9999 wt.-% and above and comprising fluorocarbon impurity in the concentration less 0.0001 wt.-%. Invention provides enhancing purity of octafluorocyclobutane.

EFFECT: improved purifying method.

26 cl, 13 tbl, 10 ex

 

This application is filed under 35 U.S.. §111 (a) with the use of priority in accordance with 35 U.S.. §119 (e) (1) the filing date of the provisional application 60/264,322, filed January 29, 2001, in accordance with 35 U.S. §111(b)

The technical field

The present invention relates to a method of cleaning OCTAFLUOROCYCLOBUTANE, the method of producing OCTAFLUOROCYCLOBUTANE high purity, OCTAFLUOROCYCLOBUTANE high purity and its application.

Prior art

Earlier in the production method of semiconductor devices held gas etching to partially remove the thin-film material for forming the circuit pattern, which is constituted of a semiconductor circuit. At the same time carried out the removal of sediment when using cleaning gas for removing the source material of a thin film deposited inside the reactor during the formation of a thin film. One suitable etching gas or a cleaning gas, the traditional method of production of semiconductor devices, is OCTAFLUOROCYCLOBUTANE (indicated hereinafter referred to as FC-C318).

On the other hand, to meet the latest trends toward higher performance, smaller size, higher density wiring electrical or electronic equipment, the circuit pattern becomes finer, and that is to form the circuit pattern high accuracy by etching, requires the use of highly purified etching gas from which impurities are removed as much as possible. When the etching gas that contains the impurity even in small quantities, it can cause the formation of lines of large width at the time of formation of a fine pattern and increase the defects in a product containing an integrated circuit of high density.

Also in the method for removing sediment when using cleaning gas residual impurities in the manufacture of a semiconductor device after cleaning should be reduced as much as possible to ensure a high quality device that is of high purity. This requires highly purified purifying gas containing essentially no impurities.

As for the method of obtaining FC-C318, for example, a known method of purification of FC-C318, obtained as a byproduct in the manufacture of tetrafluoroethylene (hereinafter sometimes referred to here as "FC-1114) or hexaferrite (hereinafter sometimes referred to here as "PC-1216").

However, these FC-1114 and FC-1216 each receive thermal decomposition of Chlorodifluoromethane (hereinafter sometimes referred to here as "HCFC-22"), as described, for example, in EP 451793, and many kinds of substances obtained by means of this thermal decomposition. The reaction product also contains unreacted HCFC-22 and many chlarotera is their connection.

The boiling point of FC-C318 and related compounds after thermal decomposition of HCFC-22 are presented in Table 1. Among them, FC-114 and FC-1216 as target products and unreacted HCFC-22 can be largely separated by distillation.

However, chlorofluorocarbons, in particular 2-chloro-1,1,1,2,3,3,3-Heptafluoropropane (hereinafter sometimes referred to here as "CFC-217ba"), 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane (hereinafter sometimes referred to here as "CFC-217ca"), 2-chloro-1,1,1,2-Tetrafluoroethane (hereinafter sometimes referred to here as "HCFC-124"), 1-chloro-1,1,2,2-Tetrafluoroethane (hereinafter sometimes referred to here as "HCFC-124a"), 1,2-dichlorotetrafluoroethane (hereinafter sometimes referred to here as "CFC-114"), FC-1216 and 1H-Heptafluoropropane (hereinafter sometimes referred to here as "HFC-s"), have a boiling point close to the boiling point of FC-S, and hence FC-318 containing the impurity concentration of 1 parts by weight per million (CNM) or less, can hardly be obtained by separation by distillation.

Table 1
The name of the connectionThe structural formulaBoiling point (°C)
OCTAFLUOROCYCLOBUTANE (FC-C318)with-CF2CF2CF2CF2--6
Chlorodifluoromethane (HCFC-22)CHClF2-41
Exaft propen (FC-1216) CF3CF=CF2-31
2-chloro-1,1,1,2,3,3,3-Heptafluoropropane (CFC-217ba)CF3lFF3-2
1-chloro-1,1,2,2,3,3,3-Heptafluoropropane (CFC-217ca)CClF2CF2CF3from -2 to -1
2-chloro-1,1,1,2-Tetrafluoroethane (HCFC-124)CF3lF-12
1-chloro-1,1,2,2-Tetrafluoroethane (HCFC-124a)CClF2CHF2-10,2
1H-Heptafluoropropane (HFC-227ca)F2CF2CF3-19
1,2-dichlorotetrafluoroethane (CFC-114)CClF2CClF2-3,8

Therefore, the tested method of treatment other than separation by distillation, such as extractive distillation, membrane separation and adsorption separation.

However, the method of extractive distillation has the disadvantage that the equipment is very expensive and the process is difficult. The method of membrane separation has the disadvantage that a suitable and practical membrane having the properties required for the Department FC-C318 from impurities, is not known, and clean-up of high purity, for example, such that the content of impurities FC-C318 is 1 wt. ppm or less, difficult.

As shown in Table 2, there are almost no differences in molecular size (calculated value at steady state patterns) between FC-C318 and impurity compounds, there is only a small difference in boiling point between FC-C318 and impurity compounds, as described above, and FC-C318 and impurities close to the structure and physical properties. Therefore, the Department FC-C318 from impurity compounds for obtaining FC-C318 high purity can hardly achieve by way of adsorptive separation using a known adsorbent, such as activated carbon, silica gel, zeolite (molecular sieve) and carbon molecular sieve (hereinafter designated as “UMC”)

Table 2
Connection nameMolecular size (calculated value)
OCTAFLUOROCYCLOBUTANE (FC-C318)from 5.2 to 5.8
2-chloro-1,1,1,2,3,3,3-Heptafluoropropane (CFC-217ba)from 4.0 to 6.2
1-chloro-1,1,2,2,3,3,3-Heptafluoropropane (CF-CA)from 3.9 to 6.1
2-chloro-1,1,1,2-Tetrafluoroethane (HCFC-124)from 4.3 to 5.6
1-chloro-1,1,2,2-tet is aftrican (HCFC-124A beaches) from 4.3 to 5.6
1,2-dichlorotetrafluoroethane (CFC-114)from 4.8 to 5.6
Hexaferrite (FC-1216)from 4.9 to 5.9
1H-Heptafluoropropane (HFC-227ca)from 4.3 to 6.2

One of them activated charcoal is effective for the absorption and removal thus FC-1216, which is one of the impurity compounds, but all other impurities, including compounds with chlorine, can not be separated.

Therefore, conventional methods of cleaning hard to get FC-C318, with a reduced concentration of fluorocarbon impurities, in particular, CFC-217ba, up to 1 wt. ppm or less.

As a result of extensive studies to solve these problems, the authors found that when crude OCTAFLUOROCYCLOBUTANE containing impurities such as fluorocarbon, interacts with corrosive impurities agent containing the iron oxide and the compound of alkaline earth metal, and then with an adsorbent, these impurities can essentially easily removed.

More specifically, the inventors have discovered a method of purification of FC-C318, where FC-C318 containing impurities of fluorocarbon, such as CFC-217ba, CFC-217ca, HCFC-124, HCFC-124a, CFC-114, HFC-sa, particularly CFC-217ba, in a concentration of from 10 to 10,000 wt. ppm, usaimage is there with corrosive impurities agent and then with an adsorbent, and thus these impurities can be reduced to less than 1 wt. ppm. The present invention is made on the basis of this discovery.

The object of the invention

The present invention is to solve the above problems of the standard methods and the provision of a method of purification of OCTAFLUOROCYCLOBUTANE, where impurities can be essentially removed from the crude OCTAFLUOROCYCLOBUTANE containing impurities. More specifically, another object of the present invention is to provide a cleaning method capable of efficiently remove CFC-217ba, which is difficult to remove by ordinary cleaning methods, and reduce the amount of impurities, such as fluorocarbon, to less than 1 wt. ppm.

The next object of the present invention is the provision of a method of producing OCTAFLUOROCYCLOBUTANE, including the above-described stage of treatment, and the provision of high-purity OCTAFLUOROCYCLOBUTANE and its use.

Summary of invention

The way to clean OCTAFLUOROCYCLOBUTANE according to the present invention includes a step of interaction the crude OCTAFLUOROCYCLOBUTANE containing impurities with corrosive impurities agent at elevated temperature (heating) and then with an adsorbent to essentially remove impurities from the crude OCTAFLUOROCYCLOBUTANE.

Razlog the store admixture agent preferably includes iron oxide and the compound of alkaline earth metal.

The iron oxide is preferably an oxide of iron (III). Iron oxide (III) is preferably γ-hydroxyoxide iron (III) and/or γ-iron oxide (III).

Connection alkaline earth metal preferably represents at least one compound selected from the group consisting of oxides, hydroxides and carbonates of alkaline earth metals magnesium, calcium, strontium or barium.

Demoralizing impurities agent preferably contains from 5 to 40 wt.% iron oxide and from 60 to 95 wt.% compounds of alkaline earth metal per total weight of impurities present and degrades agent.

Demoralizing impurities agent is preferably granules containing powder of iron oxide having an average particle size of 100 μm or less, and the powder of the alkali earth metal having an average particle size of 100 μm or less.

Demoralizing impurities agent is preferably granules having an average particle size of from 0.5 to 10 mm

Raw OCTAFLUOROCYCLOBUTANE preferably interacts with corrosive impurities agent at a temperature of from 250°to 380°C.

The adsorbent is preferably one adsorbent selected from the group comprising activated carbon, carbon molecular sieves and activated carbon.

Activated charcoal is preferable to depict is to place an activated carbon, obtained by a process comprising a stage of washing raw coal acid and water (stage 1), heat source coal at a temperature of from 50 to 250°C in a stream of inert gas for recovery and/or dehydration of raw coal (stage 2), heat source coal at a temperature from 500 to 700°C in a flow of inert gas to recarbonation the original coal (stage 3) and the heat source of the coal at a temperature of from 700 to 900°C in a stream of a gas mixture containing an inert gas, carbon dioxide and steam to activate the original coal (stage 4).

The original coal is preferably obtained by carbonization of one of the members selected from the group consisting of carbon from coconut husk, coal, wood coal and coal tar pitch by heating from 400 to 600°C.

The acid is preferably an inorganic acid and the concentration of the acid is preferably from 1 to 1000 mol/m3.

The acid is preferably hydrochloric and/or sulphuric acid.

During the transition from stage 2 to stage 3 source coal from stage 2 is preferably heated from 500 to 700°C at 300 to 500°C./h in a stream of inert gas.

During the transition from stage 3 to stage 4 original coal from stage 3 is preferably heated from 700 to 900°C at 100 to 200°C in a stream of inert gas.

The gas mixture preferably contains from 50 to about 89. %inert gas, from 10 to about 30. % of carbon dioxide and from 1 to about 20. % steam in the total volume of the gas mixture.

After stage 4 of the activated carbon from the stage 4 is preferably cooled to room temperature at 200 to 300°C./h in a stream of inert gas.

The amount of iodine adsorption activated carbon is preferably from 700 to 1000 mg/g

The total content of alkali metals contained in the activated carbon is preferably 1000 ppm or less.

The alkali metal is preferably potassium, and total potassium content in the activated carbon is preferably 500 ppm or less.

Raw OCTAFLUOROCYCLOBUTANE preferably contains impurities in an amount of from 10 to 10,000 wt. ppm.

The admixture is preferably at least one fluorocarbon selected from the group consisting of 2-chloro-1,1,1,2,3,3, 3-Heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane, 1-chloro-1,2,2,2-Tetrafluoroethane, 1-chloro-1,1,2,2-Tetrafluoroethane, 1,2-dichloro-1,1,2,2-Tetrafluoroethane, hexaferrite and 1H-Heptafluoropropane.

After impurities are essentially removed, the concentration of impurities remaining in OCTAFLUOROCYCLOBUTANE, preferably less than 1 wt. ppm.

The method of producing OCTAFLUOROCYCLOBUTANE according to the present invention includes a stage of obtaining the crude OCTAFLUOROCYCLOBUTANE containing impurities, the interaction of the crude OCTAFLUOROCYCLOBUTANE with corrosive impurities agent at elevated temperature (heating) and then with an adsorbent to obtain OCTAFLUOROCYCLOBUTANE, from which pollutants are being removed.

The stage of obtaining the crude OCTAFLUOROCYCLOBUTANE containing impurities may be by thermal decomposition of Chlorodifluoromethane. Also, the impurity is at least one fluorocarbon selected from the group comprising 2-chloro-1,1,1,2,3,3,3-Heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane, 1-chloro-1,2,2,2-Tetrafluoroethane, 1-chloro-1,1,2,2-Tetrafluoroethane, 1,2-dichloro-1,1,2,2,-Tetrafluoroethane, hexaferrites and 1H-Heptafluoropropane.

OCTAFLUOROCYCLOBUTANE according to the present invention is characterized by a content of less than 0,0001% by weight fluorocarbon impurities and has a purity of 99,9999% by weight or more.

The fluorocarbon is at least one of the fluorocarbons selected from the group comprising 2-chloro-1,1,1,2,3,3, 3-Heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane, 1-chloro-1,2,2,2-Tetrafluoroethane, 1-chloro-1,1,2,2-Tetrafluoroethane, 1,2-dichloro-1,1,2,2,-Tetrafluoroethane, hexaferrites and 1H-Heptafluoropropane.

Gas according to the present invention is characterized by the content of the above-mentioned OCTAFLUOROCYCLOBUTANE.

The etching gas according to the present invention is characterized by the content of the above-described gas.

The cleaning gas according to the present invention is characterized by the content of the above-described gas.

Detailed description of the invention

[Cleaning method OCTAFLUOROCYCLOBUTANE]/p>

The way to clean OCTAFLUOROCYCLOBUTANE according to the present invention includes a step of interaction the crude OCTAFLUOROCYCLOBUTANE containing impurities with corrosive impurities agent at elevated temperature (heating) and then with an adsorbent to remove essentially impurities from the raw OCTAFLUOROCYCLOBUTANE. This purification method is described in detail below.

Used in the present invention, the term “crude OCTAFLUOROCYCLOBUTANE” means OCTAFLUOROCYCLOBUTANE containing impurities, which is not passed through a purification stage. Also, as used herein, the term “essentially remove” means that absolutely no impurities or almost no impurities are not contained.

Demoralizing impurities agent

In the present invention preferably uses a demoralizing impurities agent containing the iron oxide and the compound of alkaline earth metal.

Examples of the iron oxide preferably include an oxide of iron (II) or iron oxide (III). Among them, iron oxide (III) is preferred. Iron oxide (III) is preferred γ-F (γ-hydroxy iron oxide) and γ-Fe2O3(γ-iron oxide (III)), and γ-Reaon is the most preferred.

These oxides can be used individually or in combination with a variety of oxides of iron.

Polag the Ute, what is the reason γ-F and γ-Fe2O3preferred α-Fe2O3associated with the activity of iron oxide. γ-F and γ-Fe2O3have a greater reactivity and activity in relation to compounds of chlorine is in order γ-F>γ-Fe2O3>α-F>Fe2O3>>α-Fe2O3. I believe that this difference in activity compared to compounds chlorine exists because the binding energy between the iron atom and an oxygen atom in γ-FeOOH or γ-Fe2O3lower than in α-F.

Connection alkaline earth metal for use in the present invention is preferably a hydroxide, oxide or carbonate of the alkaline earth metal. Examples of the alkali earth metal is magnesium, calcium, strontium and barium.

Among these compounds, alkaline earth metals, preferably using a hydroxide or calcium oxide, and calcium hydroxide is the most preferred. These compounds are alkaline earth metals can be used separately or in combination from a variety of compounds of alkaline earth metals.

Demoralizing impurities agent for use in the present invention preferably contains iron oxide and connection Molochnoe the additional metal so that the amount of iron oxide ranged from 5 to 40 wt.%, preferably from 20 to 30 wt.%, and the number of connections alkaline earth metal ranged from 60 to 95 wt.%, preferably from 70 to 80 wt.%, accordingly, in the total mass of impurities present and degrades agent.

I believe that when the amount of iron oxide and compounds of the alkaline earth metal contained in corrupting impurities agent falls within the above limit, the decomposition of impurities and removing the decomposed products can be efficiently carried out, as described above, whereby it may be made effective cleaning with use of the characteristic properties of iron oxide and compounds of alkali-earth metal.

The form of impurities present and degrades the agent is not in a special way limited, but preferably is a form in the form of particles. In the case where the iron oxide and the compound of the alkali earth metal is in the form of particles, the average particle size before mixing, namely, before the formation of impurities present and degrades agent is preferably 100 μm or less, more preferably 10 μm, more preferably 1 μm or less. The average particle size is preferably from 0.01 to 100 μm, more preferably from 0.01 to 10 μm, more preferably from 0.01 to 1 μm.

When the average RA which measures particles of each particle of iron oxide and compounds of the alkali earth metal is 100 μm or less, can be obtained OCTAFLUOROCYCLOBUTANE with a higher degree of purity and can be carried out effectively cleaning. I believe that this is because when the iron oxide and compounds of alkali metal each is a small particle, the specific surface area of each is increased, and the iron oxide and the compound of the alkaline earth metal is easily dispersed in each other, as a result, the iron oxide and the compound of alkaline earth metal increase the size and connectivity of the crude OCTAFLUOROCYCLOBUTANE with corrosive impurities agent.

The concentration and type of impurities in the iron oxide and the compound of the alkaline earth metal is not particularly limited insofar as it does not affect the ability to decompose the impurities in the raw OCTAFLUOROCYCLOBUTANE.

The form of impurities present and degrades agent is not limited in a special way, and demoralizing impurities agent can be used in any form, but demoralizing impurities agent is preferably granules in the form of particles. Specific examples of these granules include the form of balls and spherical in shape. The average particle size of the granules is preferably from 0.5 to 10 mm, preferably from 1 to 5 mm

When the average particle size of the granules falls within the above limit, the possibility of interaction of impurities with the corrosive n is imesi agent increases, and decomposition and removal of impurities can be carried out effectively. If the average particle size of the impurities present and degrades agent exceeds 10 mm, the surface area involved in the adsorption and diffusion of gas is reduced accordingly, and the diffusion rate is sometimes reduced. On the other hand, if the average particle size of the impurities present and degrades agent is less than 0.5 mm, the surface area involved in the adsorption and diffusion is increased, although the diffusion rate may be higher when the number of processed gas increases, sometimes there is a large pressure drop.

To obtain the impurities present and degrades agent containing the iron oxide and the compound of alkaline earth metal mixed oxide powder and iron powder compound of an alkali metal, and the method for the present and degrades impurities agent is not limited. Upon receiving (granulation) pellets, as long as the mixing ratio is within the above range, satisfactory granulation can be achieved by adding water to the mixture. In the case when the size of the iron oxide particles or compounds of alkaline earth metal slightly more granulation can be carried out by adding a binder together with water. The type and amount of binder is not limited, and can be used known swazoo is it because it does not affect the properties of the resulting impurities present and degrades agent. Examples of inorganic binders include clay and gypsum, and examples of organic binders include methylcellulose, polyvinyl alcohol and starch.

This granulated demoralizing impurities agent can be obtained by mixing iron oxide and compounds of alkali-earth metal, the addition of an appropriate amount of water, stirring the mixture and granulating mix preforms.

Kneading machine, required for mixing and granulation, may have a structure in which the mixing and granulation are carried out simultaneously or in which the mixing and granulation are carried out separately. Examples of the kneading machine, where the mixing and granulation are at the same time, include a Henschel mixer, and the mixer with a vertical rotor. You can also carry out the mixing in a Henschel mixer or a V-type and granulation carried out in the disc or drum granulator granulator.

Thus obtained granules are dried preferably at a temperature of from 100 to 150°C for 3 to 5 hours in a stream of inert gas, such as air and nitrogen, in order to increase the hardness and to evaporate the water contained. The water content of corrupting impurities agent after drying may be satisfactory if the pot is a number in the mass after drying at 110°C for 2 to 3 hours in an air dryer is 1 wt.% or less.

I believe that the use of such impurities present and degrades agent impurities in the raw OCTAFLUOROCYCLOBUTANE, such as fluorocarbon, react with the compound of alkaline earth metal in corrupting impurities agent and thus destroyed. More specifically, CFC-217ba reacts with the hydroxide, oxide or carbonate of the alkaline earth metal in corrupting impurities agent with obtaining fluoride and chloride alkaline earth metal and at the same time obtain monoxide and water. The carbon monoxide and the water produced in this reaction process, respond when using iron as a catalyst for the further production of hydrogen and methane. I believe that such reactions occur continuously, whereby the chlorine in CFC-217ba is replaced obtained with hydrogen to obtain 2N-Heptafluoropropane (hereinafter sometimes designated here as “HFC-227ea”). HFC-227ea can be removed by the adsorbent, which is described next.

OCTAFLUOROCYCLOBUTANE decomposed into a number of hundreds masons in contact with corrosive impurities agent when heated to obtain cyclohexatriene (hereinafter sometimes designated here as “FC-C1316”), but may be removed by the adsorbent, which is described below.

The adsorbent

In the cleaning method according to the present invention unpeeled OCTAFLUOROCYCLOBUTANE further contact with adsorb nom after contact with corrosive impurities agent at elevated temperature.

The adsorbent used here is preferably a member selected from the group comprising activated carbon, carbon molecular sieves and activated carbon. Activated carbon, carbon molecular sieves or activated carbon can be subjected to preliminary processing before use, such as treatment with acid, heat treatment and steam treatment.

Of them in the present invention, preferably, when the activated carbon is subjected to the above pretreatment, in particular the preferred activated carbon obtained by the process comprising the following four stages, which are described below.

The above-described adsorbents may be used alone or in combination of many adsorbents.

(Method of obtaining activated carbon)

The method of obtaining activated carbon, which is particularly preferred, as described in more detail below. The method of obtaining activated carbon includes the following four stages:

(1) stage 1: washing of raw coal for the above activated carbon acid and water,

(2) stage 2: heat source coal at a temperature of from 50 to 250°C in a stream of inert gas, to restore and/or degidratiruth original coal

(3) stage 3: the heat source is about coal at a temperature from 500 to 700°C in a stream of inert gas, to carbonizate the original coal, and

(4) stage 4: the heat source of the coal at a temperature of from 700 to 900°C in a stream of a gas mixture containing an inert gas, carbon dioxide and steam to activate the original coal.

The original coal, washed in stage 1, can also be used as adsorbent, however, it is preferable to use activated carbon obtained by the process comprising stages 1 to 4.

(Original charcoal for activated carbon)

As the source of carbon can be used, at least one representative selected from the group comprising carbon from coconut husk, coal, charcoal and coal tar pitch. Given the density of coal necessary for the development of long hardness, as the adsorbent, it is preferable to use carbon from coconut husk.

The original coal carbonizer when heated (carbonization), and the temperature of carbonization is not particularly limited, but the original coal preferably carbonizing at a temperature of from 400 to 600°C., where almost no pores do not develop, more preferably at a temperature of from 400 to 500°C.

Thus obtained original coal is preferably treated with a series of stages, i.e., by washing with acid and water (stage 1), by carrying out recovery and/or dehydration (stage 2), the conduct of the river is bonisoli (stage 3) and the activation (stage 4).

(Stage 1)

Original charcoal for activated carbon is first washed with acid and water.

Examples of acids for use in the acid leaching stage 1 include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid, and organic acids such as acetic acid and triperoxonane acid. Of them preferred inorganic acid, and hydrochloric acid and/or sulfuric acid is more preferable. Taking into account the obtained metal salt, hydrochloric acid is particularly preferred.

The concentration of the acid is preferably from 1 to 1000 mol/m3, more preferably from 200 to 500 mol/m3. When the concentration of the acid is less than 1 mol/m3the effect of metal removal may decrease, whereas when it is increased to 1000 mol/m3the rinsing effect can be intense. The volumetric ratio of acid solution used for the acid to the original coal (acid solution/ source coal) is preferably from 1/1 to 5/1, more preferably from 1/1 to 2/1. When the volume ratio is less than 1/1, the action of the acid is reduced, whereas when the volumetric ratio of 5/1 acid can be intense.

The time of leaching acid is changed depending on the temperature of washing is not particularly limited. In case of high temperature washing (for example, from 30 to 100°C) washing time is several hours (for example, from 1 to 12 hours) and in the case of an ordinary temperature (for example, from 10 to 30°C) leaching is carried out, allowing the original coal processed approximately a whole day and night (for example, from 12 to 24 hours). For this time of washing the metal content in raw coal can thoroughly clean up.

Water rinse following the wash acid is performed to remove the remaining dissolved metal salts of the original coal. Accordingly, water that is suitable for use, is water with a reduced content of metal salts, such as pure or purified water. The method of washing when washing with water is not particularly limited, and full flushing is carried out or a continuous process or a batch process.

The water rinse is usually carried out up until the pH of leaching solution after leaching reaches values from 3 to 5.

Drying of raw coal after washing with water can be independently hold up to stage 2, or can be performed in stage 2, which is described later.

By washing raw coal acid and water from it can be removed metals, in particular alkaline earth metals. If metal, in particular alkali metals, remains in the original coal, he de is there as the catalyst in stage 4, as described next, the reaction proceeds between the gas used for activation (e.g., steam, carbon dioxide) and carbon atom in the original coal, and this sometimes made it difficult to control the pore size.

(Stage 2)

The original coal is heated in a stream of inert gas for recovery and/or degidrirovaniya the original coal.

This inert gas can be used in a variety of inert gases, and among them, nitrogen is preferred.

The flow rate of the inert gas and the processing time are not specifically limited, however, they are chosen appropriately so that the contained oxygen and water are released from the original coal, could be safely removed outside the system.

The temperature of the heating source of coal in a stream of inert gas is satisfactory up until it is lower than the temperature at stage 3, and is constant, and does not cause the re-carbonization. The temperature of the heating stage 2 is preferably from 50 to 250°C., more preferably from 100 to 250°C.

In stage 2, when the temperature of the heating falls within the above limit, the temperature of the re-carbonization stage 3, which is described later, can be gradually increased.

Because of the heat and therefore the recovery and/or dehydration of the original coal is, recarbonization in stage 3 may be less affected by the source of oxygen.

(Stage 3)

The original coal recarbonation when heated. The rate of increase of temperature in the transition from stage 2 to stage 3 is preferably higher, and preferably selected from a range from 300 to 500°C./HR When the rate of increase of temperature is less than 300°C/h contained resin cannot be removed as a volatile substance by dry distillation, and it is likely that the increase in macropores is not happening. The temperature increase is preferably carried out in a stream of inert gas.

The re-carbonization temperature is preferably from 500 to 700°C., more preferably from 600 to 700°C. When the temperature of the re-carbonization is less than 500°C, the volatile materials are not satisfactorily removed, and the distance distribution then becomes wide, whereas when the temperature is high, the carbon matrix may shrink, causing a reduction in the micropores. Similarly, when the re-carbonization temperature exceeds 700°C, the carbon matrix may shrink, causing a reduction in the micropores.

The time of re-carbonization is from 1 to 2 hours.

Processing in the form of re-carbonization is preferably carried out in a stream of inert gas, and can be used in a variety of inert gases as tachogenerator gas, but the preferred is nitrogen.

The flow rate of the inert gas is preferably from 2 to 10 l/min, more preferably from 3 to 5 l/min to 1 l of processed raw coal.

Through the re-carbonization and therefore the dry distillation of the original coal, from which you have removed the metal at the previous stage 1, can be achieved by decomposition of the resin, the emergence and growth of carbonated macropores and carbonization of the resin, and thus at the stage 4 can be efficiently carried out the emergence and growth of pores.

(Stage 4)

Recarbonation initial coal in stage 3 communicates with a gas mixture when heated to activate the original coal.

Used herein, the term “activation” means that the pores of the original coal is growing, and therefore the source is activated charcoal.

Assume that the activation is performed as follows. Closed pores in the crystals inside the original coal open (first stage) and the walls between adjacent pores disappear completely, forming pores of large size (second stage).

The gas mixture used in stage 4, is not specifically defined, so far as activation is not impaired, however, the gas mixture containing an inert gas, carbon dioxide and steam, is preferred. Kind of the inert gas is not particularly defined the Yong, but the preferred is nitrogen.

When the gas used in stage 4 is above a gas mixture, the steam is mixed with nitrogen as the inert gas and carbon dioxide, which reacts with carbon with relatively lower speed than steam, so that the activation can be carried out moderately.

If air (oxygen) is used as the gas mixture, the reaction between the oxygen and the carbon source coal produces a large amount of heat, so the temperature in the furnace can not be easily controlled, and there is a partial overheating, resulting in the activation cannot be performed uniformly. If you are using one of the pairs, the reaction between steam and carbon is relatively rapid, resulting in difficult to control the pore size.

The gas mixture containing the above-described inert gas, carbon dioxide and steam, has a composition mixtures in which the amount of inert gas is preferably from 50 to about 89. %, more preferably from 70 to about 80. %, the amount of carbon dioxide is preferably from 10 to about 30. %, more preferably from about 15 to about 25. %and the amount of steam is preferably from 1 to about 20. %, more preferably from 2 to about 10. %respectively in the total volume of the gas mixture.

When the quantitative ratio in the gas mixture ass is up in the above range, the reaction of carbon in raw coal with steam can be carried out moderately and processing in the form of activation may be carried out effectively.

The flow rate of the gas mixture is preferably from 0.5 to 3 l/min, more preferably from 1 to 2 l/min to 1 l of processed raw coal.

Each stage 2 through 4 hold when heated, and therefore, these steps are preferably performed continuously, in particular, stages 3 and 4 at a higher temperature.

The rate of increase of temperature from stage 3 to stage 4 is preferably from 100 to 200°C/h

When the rate of increase in temperature falls within the specified limits, the transition from stage 3 to stage 4 can be carried out efficiently.

When the rate of increase of temperature from stage 3 to stage 4 is less than 100°C./h, the closed pores in the crystals of carbon sometimes don't open and the increase in surface area does not occur, whereas when the rate of increasing the temperature exceeds 200°C/h, it is highly likely that the specific surface area and pore size grow too.

The temperature of activation is preferably from 700 to 900°C., more preferably from 800 to 900°C.

When the temperature of activation is less than 700°C, the opening and enlargement of pores occur unsatisfactory, whereas when the rate is temperature exceeds 900°C., the opening and the increase can't be easily controlled.

The time of activation has such a tendency that when the processing time is lengthened, the size of pores of the activated carbon becomes larger. Processing time varies depending on the size of the impurities, which are removed by adsorption, and is not specifically limited.

For example, in the case adsorbiruyuschee impurities contained in OCTAFLUOROCYCLOBUTANE, the processing time is preferably from 1 to 20 hours, more preferably from 5 to 18 hours.

After activating the source of coal in stage 4 of the original coal is preferably cooled down to room temperature in a stream of inert gas. In this case, the rate of temperature decrease is satisfactory up until in essence you will not see changes in the pores after activation. The speed of lowering the temperature is preferably high, but preferably is in the range from 200 to 300°C/h

When the rate of temperature decrease is less than 200°C./h, requires a lot of time for lowering the temperature, and the adsorbent controlling the pore size can cause changes in the pores.

The flow rate of the inert gas used for cooling, preferably high for smooth removal of heat captured by the adsorbent, from the system, however,the flow velocity is preferably from 1.5 to 3 l/min to 1 l of the treated coal.

In this way the resulting angle is much reduced content of alkali metals, because the original coal is washed with acid and water. The total content of alkali metals contained in the activated carbon is preferably 1000 ppm or less, more preferably from 50 to 800 ppm.

In particular, the potassium content is preferably 500 ppm or less, more preferably 200 ppm or less, even more preferably from 10 to 200 ppm.

The content of alkali metal in the adsorbent can be determined, for example, by ashing of the adsorbent, by dissolving it in acid and measurement of the content according to ICP (inductively connected plasma emission spectrochemical analysis).

The amount of adsorption of iodine thus obtained activated carbon is preferably from 700 to 1000 mg/year the Amount of adsorption of iodine can be determined by way of measurement in accordance with JIS K1474.

The method of purification of the crude OCTAFLUOROCYCLOBUTANE

The way to clean OCTAFLUOROCYCLOBUTANE according to the present invention includes a stage of the interaction of the crude OCTAFLUOROCYCLOBUTANE containing impurities with corrosive impurities agent at elevated temperature (heating) (cleaning stage 1) and further interaction with the adsorbent (cleaning stage 2). Raw OCTAFLUOROCYCLOBUTANE Ave is suitable for the present invention, may or product, obtained in a known manner, or product available on the market.

(Cleaning stage 1)

As for the reaction of decomposition of impurities, such as fluorocarbon, in the raw OCTAFLUOROCYCLOBUTANE, for example, the corrosive impurities agent fill the reactor for decomposition and served in the reactor raw OCTAFLUOROCYCLOBUTANE to interact crude OCTAFLUOROCYCLOBUTANE with corrosive impurities agent. Stage interaction is not limited in a special way, however, for example, it is preferable to apply a continuous conducting flow method using a fixed layer.

As for the pressure of the reaction, the pressure can be applied or not applied, and the treatment usually can be conducted under pressure, easy to control, however, the reaction is preferably carried out under pressure, that is, the mean excess pressure, which ranges from 0 to 2 MPa, more preferably from 0 to 1 MPa.

The size (volume) of the reactor for the decomposition and the volumetric rate is not limited in a particular way, because raw OCTAFLUOROCYCLOBUTANE and demoralizing impurities agent can interact within a certain period of time, however, they are preferably installed such that the residence time of the crude OCTAFLUOROCYCLOBUTANE in the reactor DL the decomposition is from 1 to 30 seconds, more preferably from 4 to 30 seconds.

The temperature of the decomposition reaction in the reactor for the decomposition is preferably from 250°to 380°C., more preferably from 280 to 360°C. When the temperature of the decomposition reaction falls within this limit, demoralizing impurities, the agent can maintain its activity. If the temperature of the decomposition reaction is less than 250°C, the activity of the impurities present and degrades agent is not supported, and the rate of decomposition is slow, whereas if the reaction temperature decomposition exceeds 380°C, demoralizing impurities agent itself decomposes due to heat and decomposition of impurities in the raw OCTAFLUOROCYCLOBUTANE may not occur.

(Cleaning stage 2)

After the cleanup phase 1 admixture further interact with the adsorbent and thereby essentially removed, which may be obtained OCTAFLUOROCYCLOBUTANE a high degree of purity.

The adsorption process can be carried out, for example, location of the adsorbent in the adsorption column and feeding back the crude OCTAFLUOROCYCLOBUTANE after decomposition reaction. In this case, the method of conducting the adsorption is not limited, and can be used a known method, for example, it is preferable to apply a continuous conducting flow method using a fixed layer.

When entries batch and the crude OCTAFLUOROCYCLOBUTANE, passed through a purification stage 1, the adsorbent can be used in either gas phase or liquid phase. Preferred linear velocity, in the case of gas-phase method of interaction, from 1 to 10 m/min, more preferably from 1 to 5 m/min, and in the case of liquid-phase method of interaction is preferably from 0.2 to 5 m/h, more preferably from 0.5 to 2 m/h

Treatment usually can be conducted under pressure, easy to control, and a separate operation, such as the application of pressure is not necessary. Typically, the pressure is preferably from 0 to 2 MPa in the value of the excess pressure.

The temperature of the adsorption process may be usually room temperature, and the heating or cooling are not necessary.

When the adsorption capacity of the adsorbent is saturated, the adsorbent can be regenerated and used. In this case, regeneration of the adsorbent is performed by transmission of various inert gases such as nitrogen, heated to a high temperature, through the adsorbent and thus the desorption of OCTAFLUOROCYCLOBUTANE and impurities, such as fluorocarbon.

When the regeneration temperature of the inert gas is preferably from 100 to 400°C., more preferably from 100 to 200°C.

[Method of producing OCTAFLUOROCYCLOBUTANE]

In the method of producing OCTAFLUOROCYCLOBUTANE according infusion is his invention receive raw OCTAFLUOROCYCLOBUTANE, and then he can be held above the stage of purification in combination. More specifically, raw OCTAFLUOROCYCLOBUTANE after receiving may be the above-described purification stages 1 and 2.

The method of obtaining the crude OCTAFLUOROCYCLOBUTANE is not limited in a particular way, and can be used a known method. As described above, raw OCTAFLUOROCYCLOBUTANE can be obtained as a by-product upon receipt of tetrafluoroethylene (FC-1114) or hexaferrite (FC-1216). Each of these FC-1114 and FC-1216 can be obtained by thermal decomposition of Chlorodifluoromethane (HCFC-22), as described, for example, in the patent ER.

Thus obtained crude OCTAFLUOROCYCLOBUTANE subjected to the above cleansing stage 1 and stage of cleanup 2, whereby can be obtained OCTAFLUOROCYCLOBUTANE, from which pollutants are being removed.

[OCTAFLUOROCYCLOBUTANE high purity]

When using the cleaning method according to the present invention, an impurity containing a fluorocarbon (e.g., chlorofluorocarbons, hydrofluorocarbons) in the raw OCTAFLUOROCYCLOBUTANE, such as 2-chloro-1,1,1,2,3,3,3-Heptafluoropropane (CFC-217ba), 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane (CFC-217ca),1-chloro-1,2,2,2-Tetrafluoroethane (or 2-chloro-1,1,1,2-Tetrafluoroethane (HCFC-124)), 1-chloro-1,1,2,2-Tetrafluoroethane (HCFC-124a), 1,2-dichloro-1,1,2,2-Tetrafluoroethane (CFC-114), hexaferrites (FC-1216) and 1-Heptafluoropropane (HFC-227ca), in particular CFC-217ba, can be essentially removed, and OCTAFLUOROCYCLOBUTANE high purity can be obtained.

The above impurities normally contained in the raw OCTAFLUOROCYCLOBUTANE in the range from 10 to 10000 wt. ppm, and when using the cleaning method according to the present invention, these impurities contained in OCTAFLUOROCYCLOBUTANE may be removed to a content of less than 1 wt. ppm (of 0.0001 wt.%), and can be achieved purity of OCTAFLUOROCYCLOBUTANE obtained after purification, 99,9999% by weight or more.

Here the purity of OCTAFLUOROCYCLOBUTANE defined as the value obtained by subtracting the content of the fluorocarbon other than OCTAFLUOROCYCLOBUTANE, from 100 wt.%. Analysis of the product OCTAFLUOROCYCLOBUTANE having a purity of 99,9999% by weight or more, may be conducted (1) gas chromatography (GC), using the method of TCD, FID way (including in each case, the method pre-shutdown) or way ECD (2), and gas chromatography and mass spectrometrical (GC-MS).

[Application]

After impurities are essentially removed, OCTAFLUOROCYCLOBUTANE obtained by methods according to the present invention may be used as the etching gas phase etching of semiconductor devices.

More specifically, in the manufacture of semiconductor devices such as LSI and concope the night transistor, OCTAFLUOROCYCLOBUTANE may be suitable as the etching gas for receiving the circuit pattern of thin or thick film formed by a CVD method, a sputtering method or deposition method from the vapor phase.

OCTAFLUOROCYCLOBUTANE can also be used as a cleaning gas at the stage of purification of a semiconductor device.

More specifically, in the apparatus for forming a thin or thick film cleaning is performed to remove unwanted deposits accumulated on the inner wall of the apparatus and process of the devices, because the excess fat can generate particles and must be removed to obtain a high-quality film. OCTAFLUOROCYCLOBUTANE according to the present invention is suitable for use with this purpose as a cleaning gas.

Gas according to the present invention includes highly of OCTAFLUOROCYCLOBUTANE. This gas can be pure OCTAFLUOROCYCLOBUTANE or in addition contain other gases. Examples of these additional gases include, Ne, Ar, and O2. The amount of these gases for mixing with OCTAFLUOROCYCLOBUTANE has no special limitation, and in the case of OCTAFLUOROCYCLOBUTANE high purity according to the present invention as an etching gas or a cleaning gas is a mixed number ha is and varies depending on connection type and thickness protravlivanija layer, and can be selected depending on the number and thickness of the removed sediments.

The technical result.

In accordance with the method of cleaning or receive OCTAFLUOROCYCLOBUTANE of the present invention, impurities such as fluorocarbon, which were previously difficult to remove, can be essentially removed, and OCTAFLUOROCYCLOBUTANE high purity can be easily obtained. In addition, OCTAFLUOROCYCLOBUTANE obtained by the purification method according to the present invention are essentially free of impurities and, therefore, can be effectively used as an etching or cleaning gas for use in a method of producing semiconductor devices, etc.

Examples

The present invention is described below in more detail by way of Examples, however, should not be construed present invention as limited by these examples.

[Examples 1-3]

[Tube for the decomposition of impurities]

Demoralizing impurities agent containing the iron oxide and the compound of alkaline earth metal, was obtained with the ratio of components of the mixture γ-FeOOH (produced by Ishihara Sangyo)/CA(Oh)2(produced by Yoshizawa Sekkai Kogyo)=30/70 wt.% (Example 1), γ-Fe2O3(produced by Toda Kogyo)/CA(Oh)2=20/80 wt.% (Example 2) or γ-FeOOH/caso3(produced by Okutama Kogyo)=20/80 wt.% (Example 3). After adding water the each mixture granularit, dried at 105°C for 2 hours and sieved with obtaining a granulated product having a particle size of from 0.85 to 2.8 mm. Then 1.9 grams each present and degrades impurities agent is placed in a stainless steel tube (reaction tube)having an inner diameter of 16 mm, a layer height of 8 cm (volume 15 ml) and treated with a stream of nitrogen at 300°C for 3 hours or more to get the tube to decompose impurities.

[Adsorbent and the adsorption column]

The adsorbent was prepared as follows.

45 kg of charcoal from coconut husk (made in the Philippines) as the source of the coal is washed with hydrochloric acid having a concentration of 300 mol/m3and then repeat the washing of raw coal with water three times. The amount of hydrochloric acid having a concentration of 300 mol/m3that is the same as the volume of raw coal that is washed. After adding hydrochloric acid to the original coal is left for 15 hours and then subjected to solvent extraction. The amount of water when flushing water is equal to five times the volume of the original coal, and the end of the cycle, evidenced by the fact that the pH of the washing solution after washing is equal to 4 (see table 3).

Table 3

The results of the analysis of metals in raw coal p is red and after acid
Analysis of metals in raw coal
The metal content (wt. ppm)
ComponentBefore washing acidAfter acid
Na812119
To4950132
CA462112
Fe837103
Al876100

Then the original coal is placed in a drying oven (electric with external heating metal rotary kiln, the number of spins: cycle 8 Rev/min, inner diameter: 950 mm drum part: 620 mm, 50 kW, 150 A (max)) and dried with nitrogen at 90°C for 2 hours. Used nitrogen has a purity of 99% or more, and a flow rate of 50 l/min. In an oven-dried original coal is then subjected to recovery/dehydration (stage 2), the re-carbonization (stage 3) and activation (stage 4) under the conditions listed in Table 4.

td align="center"> 1
Table 4
StageStageTemperature (°C)Time (h)N2(l/min)CO2(l/min)H3O (l/min)
recovery/dehydration15025000
2the temperature rise150 → (650130000
3recarbonization650230000
4the temperature rise650 → (850172208
5activation8501672208
6the temperature drop850 → (600172208
7the temperature drop600 →110000

83 g of adsorbent, obtained above, are placed in a stainless steel tube with an outside diameter of 1/2 inch (12.7 mm) (adsorption column: 11 mm (inner diameter) × 150 cm (length of column), volume: 130 ml) and treated with a stream of nitrogen at 60°C for 1 hour and at 160°C for 7 hours in total for 8 hours. The obtained adsorption column connected to an end of the tube is La decomposition of impurities, filled with corrosive impurities agent.

(Obtaining the crude OCTAFLUOROCYCLOBUTANE (FC-C318))

Used raw OCTAFLUOROCYCLOBUTANE is a by-product obtained during the production of FC-1114. More specifically, FC-1114 get by thermal decomposition of HCFC-22. At this time OCTAFLUOROCYCLOBUTANE, resulting from the dimerization of FC-1114, is obtained as a by-product and distil to obtain the crude OCTAFLUOROCYCLOBUTANE. The amount of impurities in the thus obtained crude OCTAFLUOROCYCLOBUTANE determined by gas chromatography. Conditions of the analysis by gas chromatography is shown below.

Device:

GC-18A (Shimadzu Corporation)

Media: No

Detector: hydrogen flame ionization detector

The number of specimen: 0.2 ml

The method of determining the absolute calibration curve method

Fluorocarbon impurities in the crude OCTAFLUOROCYCLOBUTANE was as follows: CFC-217ba was 350 wt. ppm, CFC-217ca was 20 wt. ppm and HCFC-124, HCFC-124A beaches and CFC-114 are each comprised 10 wt. ppm.

[Purification of the crude OCTAFLUOROCYCLOBUTANE]

Raw OCTAFLUOROCYCLOBUTANE, obtained above, is passed through the gas phase under pressure of 0.2 MPa with a bulk velocity of 750 h-1through razlagaemoi impurities tube and with a linear speed of 1 m/min through adsorption to the Onna. The temperature of the decomposition reaction in the tube for the decomposition of impurities is 350°C. OCTAFLUOROCYCLOBUTANE passing through the tube for the decomposition of impurities, and OCTAFLUOROCYCLOBUTANE passing through the adsorption column, respectively, are collected and examined by gas chromatography in the above conditions.

Fluorocarbon impurities in OCTAFLUOROCYCLOBUTANE at the outlet of the reaction tube and at the outlet of the adsorption column analyzed after 5 h, 10 h and 15 h after the beginning of transmission of the crude OCTAFLUOROCYCLOBUTANE. The results are presented in Table 5.

In the CFC-217ba, CFC-217ca, HCFC-124, HCFC-124a and CFC-114 decompose by impurities present and degrades agent and almost not determine the output of the tube for the decomposition of impurities. At the same time receive HFC-227ea and FC-C1316, but these products can be removed by the adsorbent. Thus, it is confirmed that CFC-217ba, CFC-217ca, HCFC-124, HCFC-124a and CFC-114 in FC-C318 can be removed, and OCTAFLUOROCYCLOBUTANE can be cleared.

At the outlet of the adsorption column HFC-227ea and FC-C1316 not detected.

Table 5

The change in concentration of each impurity in the exit tube for the decomposition of impurities and the outlet of the adsorption column
 Travel time (h) The change in concentration of each impurity (wt. ppm)
CFC-217b andCFC-s andF-124HCFC-124aCFC-114HFC-a andFC-S 6
The number of sample 3502010101000
The output from the tube for decay5

10

15
0

0

0
0

0

0
0

0

0
0

0

0
0

0

0
57

58

43
121

99

29
The output from the adsorption column5

10

15
0

0

0
0

0

0
0

0

0
0

0

0
0

0

0
0

0

0
0

0

0

The change in the concentration of CFC-17ba contained in OCTAFLUOROCYCLOBUTANE at the outlet of the adsorption column after 2 h and 5 h from the start of transmission of the crude OCTAFLUOROCYCLOBUTANE, and removing quantities of CFC-17ba to the point of breakthrough is shown in Table 8.

Here the breakthrough point is set at the point where 1 ppm fluorocarbon impurities are detected at the outlet of the adsorption column, and the number of CFC-217ba, missed to the point of leakage, determine how remote the number of CFC-217ba.

In the case of γ-Fe2O3as iron oxide (III) (Example 2) and using caso3as compounds of alkaline earth metal (Example 3) you can also achieve a high capacity to remove the amount of CFC-217ba and confirmed that OCTAFLUOROCYCLOBUTANE can also be cleared.

(Comparative example 1)

The test is carried out under the same conditions as in Example 1, except that the decomposition of fluorocarbon impurities in the raw OCTAFLUOROCYCLOBUTANE using impurities present and degrades agent is not included in the Example 1.

The concentration of impurities before and after passing through the activated carbon determined in the same way by gas chromatography.

Fluorocarbon impurities in OCTAFLUOROCYCLOBUTANE at the outlet of the adsorption column were analyzed after 5 h, 10 h and 15 h after the beginning of transmission of OCTAFLUOROCYCLOBUTANE. The results are presented in Table 6.

As for CFC-217ba and CFC-217ca, the breakthrough point coincides with the beginning of the transmission of OCTAFLUOROCYCLOBUTANE, and confirmed that CFC-217ba and CFC-217ca cannot be removed only by the adsorbent.

Deleted quantity of HCFC-124, HCFC-124a and CFC-114 cleaning method according to the present invention (Example 1) and their remote number only also blonay cleaning (Comparative example 1) shown in Table 7.

Taking as a point of breakthrough moment when each impurity in OCTAFLUOROCYCLOBUTANE find at a concentration of 1 wt. ppm at the outlet of the adsorption column, the quantity of each admixture, missed to the point of breakthrough, is designated as a remote number. As can be seen from the results of Example 1 and Comparative Example 1, HCFC-124, HCFC-124a and CFC-114 can be removed by adsorption, however, when the stage of decomposition is to the stage of adsorption as in Example 1, HCFC-124, HCFC-124a and CFC-114 themselves decompose and already removed, so the remote can be increased compared with conventional methods, adsorption treatment, and confirmed that the cleaning method according to the present invention is more efficient.

Table 6

Changes in the concentration of each impurity at the outlet of the adsorption column (Comparative example 1)
Travel time (h)Changes in the concentration of each impurity (masons)
CFC-217 baCFC-217 saHCFC-124HCFC-124aCFC-114
The number of sample350201010 10
5

10

15
350

350

350
20

20

20
0

0

0
0

0

0
0

0

0
Table 7

Deleted quantity of HCFC-124, HCFC-124a and CFC-114
 Remote number fluorocarbon impurities (g)
 HCFC-124HCFC-124aCFC-114
Example 17,07,02,3
EUR. Example 13,53,51,3

[Comparative Examples 2 through 4]

Testing is carried out in the same conditions as in Examples 1 to 3, except that γ-FeOOH=100 wt.% (EUR. Example 2), γ-Fe2O3=100 wt.% (Comparative Example 3) and CA(Oh)2=100 wt.% (Comparative Example 4) are used as the impurities present and degrades agent. The breakthrough point is set at the moment when fluorocarbon impurity in OCTAFLUOROCYCLOBUTANE determine with a concentration of 1 wt. ppm at the outlet of hell is orcinol columns.

The change in the concentration of CFC-217ba contained in OCTAFLUOROCYCLOBUTANE, at the outlet of the adsorption column after 2 h and 5 h from the moment when you start to miss OCTAFLUOROCYCLOBUTANE, and dial the number of CFC-217ba to the point of breakthrough is shown in Table 8.

Demoralizing impurities agent containing only iron oxide (III) (Comparative Examples 2 and 3), you cannot save the form, and probably because of this, the breakthrough point in CFC-217ba starts earlier. The reaction of decomposition of CFC-217ba almost never occurs only with connection alkaline earth metal (Comparative Example 4), remote amount of CFC-217ba is very small. This implies that if you do not use demoralizing impurities agent containing the iron oxide and the compound of alkaline earth metal, mixed in the appropriate proportions, CFC-217ba almost does not decompose, and good results for removing CFC-115 can not be obtained.

The number of sample
Table 8

Changes in the concentration at the outlet of the adsorption column and dial the number of CFC-217ba in each trial
 The composition of the impurities present and degrades agent (wt.%)Travel time (h)Changes in the concentration of CFC-217ba (masons)Remote amount of CFC-217ba (mg)
 0350 
Example 1γ-FeOOH

CA(Oh)2
30

70
20645
50
Example 2γ-Fe2O3

CA(Oh)2
20

80
20570
545
Example 3γ-FeOOH

Caso3
20

80
224555
5325
EUR. Example 1Only the adsorbent 2350<1
5350
EUR. Example 2γ-FeOOH10025260
5303
EUR. Example 3γ-Fe2O3100212530
5350
With the avn. Example 4Ca(OH)21002300<1
5350

[Reference Examples 1 and 2]

The tests were carried out under the same conditions as in Example 1, except the temperature of decomposition in the tube for the decomposition of impurities. Decomposition temperature in the tube for the decomposition of impurities was 240°C. (Reference example 1) and 400°C (Reference example 2).

Changes in the concentration of CFC-217ba at the outlet of the reaction tube after 2 h, 5 h and 10 h after the beginning of transmission of OCTAFLUOROCYCLOBUTANE shown in Table 9.

As can be seen from the test results, the activity of the impurities present and degrades agent does not increase as a result of excessively low temperature 240°C, and decomposition does not occur. When an excessively high temperature of 400°C demoralizing impurities agent itself decomposes under the action of heat, and the breakthrough point CFC-217ba at the outlet of the adsorption column comes early. Remote amount of CFC-217ba is about 1 mg or less, and confirmed that this impurity was almost deleted.

Table 9

Changes in the concentration of CFC-217ba at the outlet of the adsorption column with respect to the decomposition temperature
Travel time (h) Changes in the concentration of CFC-217ba (wt. ppm)
Example 1 (350°C)Ref. Example 1 (240°C)Ref. Example 2 (400°C)
The number of sample350350350
20190225
50325350
100350350

Additional examples

Example I

Purification of the crude OCTAFLUOROCYCLOBUTANE was carried out in the same manner as in Example 1, contained in the description, except that was used crude OCTAFLUOROCYCLOBUTANE FC-C318 containing CFC-217ba 1500 ppm by weight instead of 350 ppm by weight, and the reaction temperature was changed to 300°C instead of 350°C. Remote number F-217b before the concentration of CFC-217 b at the exit of the adsorption columns was reduced to 1 ppm, amounted to 650 mg.

The results obtained are shown in Table A.

Example II

Purification of the crude OCTAFLUOROCYCLOBUTANE was carried out in the same manner as in Example 1, contained in the description, except that was used crude OCTAFLUOROCYCLOBUTANE FC-C318 containing CFC-217ba in the amount of 1700 ppm by weight instead of 350 ppm by weight. Remote amount of CFC-217ba before the oxygen is radio CFC-217ba at the exit of the adsorption columns was reduced to 1 ppm, amounted to 690 mg

The results obtained are shown in Table C.

Example III

Purification of the crude OCTAFLUOROCYCLOBUTANE was carried out in the same way as in the Example I provided in the description, except that was used crude OCTAFLUOROCYCLOBUTANE FC-C318 containing CFC-114 in the amount of 500 ppm by weight instead of 10 ppm by weight. Remote number F-217b before the concentration of CFC-217ba at the exit of the adsorption columns was reduced to 1 ppm, amounted to 270 mg of the Obtained results are shown in Table C.

Table D

Deleted from OCTAFLUOROCYCLOBUTANE number FC-217ba at the exit of the adsorption column until the concentration of each impurity was reduced to 1, 10 or 100 ppm by weight shown in Table D together with excerpts from Table 8 of the description.

Table And

Changes in the concentration of each impurity at a pipe outlet decomposition of impurities and at the outlet of the adsorption column
 Time (hrs.)Changes in the concentration of each impurity (ppm by mass)
 CFC-217baCFC-217caHCFC-124HCFC-124aCFC-114HFC-227eaFC-C1316
The obtained samples  15002010101000
The pipe outlet decomposition impurities2

5

10

15
0

2

135

560
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
250

295

210

163
98

55

20

15
The outlet of the adsorption column2

5

10

15
0

0

108

560
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0

The table In

Changes in the concentration of each impurity at a pipe outlet decomposition of impurities and at the outlet of the adsorption column
 Time (hrs.)Changes in the concentration of each impurity (ppm by mass)
CFC-217baCFC-217caHCFC-124HCFC-124A beachesCFC-114HFC-227eaFC-C1316
The obtained samples  17002010101000
The pipe outlet decomposition impurities2

5

10

15
0

0

130

505
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
26

120

145

66
98

55

30

15
The outlet of the adsorption column2

5

10

15
0

0

6

505
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0

Table

Changes in the concentration of each impurity at a pipe outlet decomposition of impurities and at the outlet of the adsorption column
 Time (hrs.)Changes in the concentration of each impurity (ppm by mass)
CFC-217bCFC-saHCFC-124HCFC-124A beachesCFC-114HFC-227eaHFC-EAFC-S
The obtained samples  350201010500000
The pipe outlet decomposition impurities2

5

10

15
0

0

6

120
0

0

0

0
0

0

0

0
0

0

0

0
0

0

50

170
57

58

43

40
81

99

50

40
121

99

29

15
The outlet of the adsorption column2

5

10

15
0

0

3

120
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0
0

0

0

0

Table D

Fixed amount of CFC-217ba in each example
 The composition of the agent, present and degrades the impurity (wt.%)Fixed amount of CFC-217ba (mg) *1Fixed amount of CFC-217ba (mg) *2Fixed amount of CFC-217ba (mg) *3
Example 1γ-FeOOH

the as(OH) 2
30

70
6457251216
Example 2γ-Fe2About3

CA(Oh)2
20

80
5706551050
Example 3γ-FeOOH

Caso3
20

80
555600980
Comparative example 1Only the adsorbent <1<1<1
Comparative example 2γ-FeOOH100608598
Comparative example 3γ-Fe2O3100304062
Comparative example 4CA(Oh)2100<1<1<1
Example Iγ-FeOOH

Ca(OH)2
30

70
6508601173
Example IIγ-FeOOH

CA(Oh)2
30

70
6908601250
Example IIIγ-FeOOH

CA(Oh)2
110

150
270455 615
*1 End when 1 ppm by mass

*2 complete the 10 ppm by mass

*3 Completion at 100 ppm by mass

1. The way to clean OCTAFLUOROCYCLOBUTANE, including the stage of interaction of the crude OCTAFLUOROCYCLOBUTANE containing impurities with corrosive impurities agent at an elevated temperature and then with an adsorbent that can remove these impurities content of less than 0,0001%by weight, of the above crude OCTAFLUOROCYCLOBUTANE, and mentioned corrupting agent contains iron oxide (III) and the compound of alkaline earth metal, the said impurity is at least one fluorocarbon selected from the group consisting of 2-chloro-1,1,1,2,3,3, 3-Heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane, 1-chloro-1,2,2,2-Tetrafluoroethane, 1-chloro-1,1,2,2-Tetrafluoroethane, 1,2-dichloro-1,1,2,2-Tetrafluoroethane, hexaferrite and 1H-Heptafluoropropane.

2. The way to clean OCTAFLUOROCYCLOBUTANE under item 1, where the specified iron oxide (III) is γ-hydroxyoxide iron and/or γ-iron oxide (III).

3. The way to clean OCTAFLUOROCYCLOBUTANE according to claim 1, where the specified connection alkaline earth metal is at least one compound selected from the group consisting of oxides, hydroxides and carbonates of Melo rosemaling metals magnesium, calcium, strontium and barium.

4. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 3, where mentioned demoralizing impurities agent contains from 5 to 40 wt. % iron oxide and from 60 to 95 wt. % of compounds of alkaline earth metal per total weight of the mentioned impurities present and degrades agent.

5. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 4, where mentioned demoralizing impurities agent is a granule containing a powder of iron oxide having an average particle size of 100 μm or less, and powder compounds of the alkali earth metal having an average particle size of 100 μm or less.

6. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 5, where mentioned demoralizing impurities agent is granules having an average particle size of from 0.5 to 10 mm

7. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 6 where the above-mentioned raw OCTAFLUOROCYCLOBUTANE interacts with said corrosive impurities agent at a temperature of from 250 to 380°C.

8. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 7, where the said adsorbent is at least one agent, selected from the group consisting of activated carbon, carbon molecular sieves and activated carbon.

9. The way to clean OCTAFLUOROCYCLOBUTANE of claim 8 where the above-mentioned activated carbon is produced by way in the stage with:

washing of raw coal acid and water (stage 1);

heating raw coal at a temperature of from 50 to 250°C in a stream of inert gas for recovery and/or dehydration is referred to the original coal (stage 2);

heating raw coal at a temperature from 500 to 700°C in a flow of inert gas to recarbonation the original coal (stage 3);

and heating raw coal at a temperature of from 700 to 900°C in a stream of a gas mixture containing an inert gas, carbon dioxide and steam to activate mentioned the original coal (stage 4).

10. The way to clean OCTAFLUOROCYCLOBUTANE according to claim 9, where these source coal produced by karbonitrirovanija at least one member selected from the group consisting of carbon from coconut husk, coal, charcoal and coal tar pitch, when heated from 400 to 600°C.

11. The way to clean OCTAFLUOROCYCLOBUTANE under item 9 or 10, where this acid is an inorganic acid, and the concentration of the said acid is from 1 to 1000 mol/m3.

12. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-11, where this acid is hydrochloric acid and/or sulphuric acid.

13. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-12, where the transition from the stage 2 referred to stage 3 source coal from stage 2 heat is up to a temperature of from 500 to 700°C at 300 to 500°C./h in a stream of inert gas.

14. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-13, where the transition from the stage 3 of the said stage 4 original coal from the stage 3 is heated to a temperature of from 700 to 900°C at 100 to 200°C./h in a stream of inert gas.

15. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-14, where this gas mixture contains from about 50 to about 89. % of inert gas, from 10 to about 30. % of carbon dioxide and from 1 to about 20. % steam in the total volume of the gas mixture.

16. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-15, where, after a specified stage 4 activated carbon with stage 4 is cooled to room temperature at 200 to 300°C./h in a stream of inert gas.

17. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of paragraphs. 9-16, where indicated, activated charcoal has the value of the quantity of adsorption of iodine from 700 to 1000 mg/g

18. The way to clean OCTAFLUOROCYCLOBUTANE on any of PP-17, where the total content of alkali metals contained in the above-mentioned activated carbon, is 1000 ppm or less.

19. The way to clean OCTAFLUOROCYCLOBUTANE on p where the above-mentioned alkali metal is potassium, and the total content of potassium contained in the above-mentioned activated carbon, is 500 ppm or less.

20. The way to clean OCTAFLUOROCYCLOBUTANE according to any one of claims 1 to 19, where the mentioned raw OCTAFLUOROCYCLOBUTANE contains KJV is anutie impurities in an amount of from 10 to 10,000 wt. ppm.

21. The way to clean OCTAFLUOROCYCLOBUTANE according to claim 1, where after the admixture is essentially removed, the concentration of impurities remaining in OCTAFLUOROCYCLOBUTANE is less than 1 wt. ppm.

22. The way to clean OCTAFLUOROCYCLOBUTANE according to claim 1, where receiving OCTAFLUOROCYCLOBUTANE with purity 99,9999 wt.% or more and containing less than 0,0001% by weight fluorocarbon impurities.

23. OCTAFLUOROCYCLOBUTANE on p.22, where the above-mentioned fluorocarbon is at least one fluorocarbon selected from the group consisting of 2-chloro-1,1,1,2,3,3, 3-Heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-Heptafluoropropane, 1-chloro-1,2,2,2-Tetrafluoroethane, 1-chloro-1,1,2,2-Tetrafluoroethane, L,2-dichloro-1,1,2,2-Tetrafluoroethane, hexaferrite and 1H-Heptafluoropropane.

24. Gas, including OCTAFLUOROCYCLOBUTANE, with a purity of 99,9999% by weight and more and containing less than 0,0001% by weight fluorocarbon impurities.

25. Etching gas including OCTAFLUOROCYCLOBUTANE with purity 99,9999 wt.% and more and containing and containing less than 0,0001% by weight fluorocarbon impurities.

26. A cleaning gas including OCTAFLUOROCYCLOBUTANE with purity 99,9999 wt.% and more and containing and containing less than 0,0001% by weight fluorocarbon impurities.



 

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