JP2013241389A - Method for drying fluid containing fluoroolefin, and method for producing fluoroolefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing only water from a fluid containing a fluoroolefin and a 1C alkane.SOLUTION: A method for drying a fluid containing a fluoroolefin and a 1C alkane whose at least one hydrogen atom may be replaced by chlorine atom or fluorine atom comprises contacting the fluid with synthetic zeolite 3A to remove water in the fluid.

Description

  The present invention relates to a method for drying a fluid containing a fluoroolefin, and a method for producing a fluoroolefin, and more particularly, a method for drying a fluid containing a fluoroolefin and an alkane having 1 carbon atom or a halogenated alkane, and such a fluid. Is dried to produce a high-purity fluoroolefin.

  2,3,3,3-tetrafluoropropene (HFO-1234yf), a kind of fluoroolefin, is a new refrigerant that replaces greenhouse gas 1,1,1,2-tetrafluoroethane (HFC-134a) In recent years, there has been great expectations. In the present specification, for halogenated hydrocarbons, the abbreviation of the compound may be written in parentheses after the compound name, but the abbreviation is used instead of the compound name as necessary.

  As a method for producing HFO-1234yf, for example, 1,1-dichloro-2,2,3,3,3-pentafluoropropane (HCFC-225ca) is dehydrofluorinated with an alkaline aqueous solution in the presence of a phase transfer catalyst. A method is known in which 1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya) obtained by the above process is used as a raw material and reduced with hydrogen.

  However, in such a method, there are problems such as high equipment costs due to a multi-stage reaction, and difficulty in distillation and purification of intermediate products and final products.To solve such problems, There has been proposed a method for producing HFO-1234yf from a raw material containing chlorofluorocarbons by a single synthesis reaction involving thermal decomposition.

  In this production method, the hydroalkane having 1 carbon atom or halogenated alkane (hydrohaloalkane) such as methane or chloromethane, the halogenated olefin having 2 carbon atoms, and 3 carbon atoms other than HFO-1234yf. Since various compounds such as halogenated olefins are by-produced, it is required to obtain high-purity HFO-1234yf.

  In addition, in the use of HFO-1234yf as a refrigerant or the like, a high level of moisture (humidity) may cause various problems in reliability and performance, so in order to suppress such harmful effects, It is required to reduce the amount of water contained in the fluid containing HFO-1234yf as much as possible.

  As a method for drying a fluid containing a fluoroolefin such as HFO-1234yf, Patent Document 1 discloses that a gas stream containing fluoropropene is provided with an opening having a size across the maximum dimension of the opening of about 3 mm to about 5 mm. A method of contacting with a synthetic zeolite is presented. Examples of the molecular sieve having an opening of about 3 to 5 mm include zeolites 3A, 4A, and 5A, and examples of drying (dehydrating) a fluid containing HFO-1234yf using these molecular sieves are described. Has been.

Special table 2009-539598

  However, Patent Document 1 does not describe an embodiment in which a fluid containing a fluoroolefin contains an alkane having 1 carbon atom such as methane or chloromethane. Further, according to the study by the present inventors, when the fluid contains an alkane having 1 carbon, the alkane having 1 carbon in the fluid is adsorbed on the molecular sieve and removed by the method described in Patent Document 1. It has been found that it is not possible to remove only water in the fluid. That is, when purifying a fluoroolefin from a fluid containing a fluoroolefin and a halogenated alkane having 1 carbon atom, first, only water in the fluid is removed (dehydrated) with a molecular sieve, and then a halogenated alkane having 1 carbon atom. However, in the experiment conducted by the present inventors, the halogenated alkane having 1 carbon atom is adsorbed on a molecular sieve having an opening of 4A or 5A. Since it was removed, it was not possible to remove only water.

  The present invention has been made from the above viewpoint, and an object thereof is to provide a method for drying a fluid that removes only moisture from a fluid containing a fluoroolefin and a hydroalkane having 1 carbon.

  In the present invention, a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom is brought into contact with the synthetic zeolite 3A, so that moisture in the fluid can be reduced. Provided is a method for drying a fluid containing a fluoroolefin, characterized in that it is removed.

  In the present invention, a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom is brought into contact with the synthetic zeolite 3A, so that the water content in the fluid is increased. A process for producing fluoroolefin is provided.

  Furthermore, the present invention provides a process for producing HFO-1234yf by subjecting a composition containing chlorodifluoromethane and chloromethane to a synthesis reaction involving thermal decomposition in the presence of a heat medium, and the HFO- 1234yf and contacting a fluid containing an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom with the synthetic zeolite 3A to remove moisture in the fluid. A method for producing HFO-1234yf is provided.

According to the method of the present invention, by using the synthetic zeolite 3A, from a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom, Only moisture can be removed without adsorbing and removing organic compounds such as alkanes having 1 carbon. Therefore, in the subsequent purification process of fluoroolefin, the organic compound such as alkane having 1 carbon can be separately separated and used for the reaction, or purified as a product.
Moreover, according to the manufacturing method of this invention, a highly purified fluoro olefin can be obtained efficiently by drying the fluid containing an above-mentioned fluoro olefin and C1-C1 alkane.

Embodiments of the present invention will be described below.
<Drying method of fluid containing fluoroolefin>
The first embodiment of the present invention is a dehydration method that removes only moisture from a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom. A drying method, wherein the fluid is brought into contact with the synthetic zeolite 3A.

(Fluoroolefin)
The fluoroolefin contained in the fluid to be treated is preferably a fluoroolefin having 2 or 3 carbon atoms. Specific examples include hexafluoropropene, pentafluoropropene, tetrafluoropropene, trifluoropropene, tetrafluoroethylene, trifluoroethylene, difluoroethylene, chlorotrifluoroethylene, and chlorodifluoroethylene. That is, at least one selected from the group consisting of the above compounds is contained in the fluid that is the object to be treated to be dried in the present invention.
As will be described later, the fluoroolefin in the present invention is chlorodifluoromethane (hereinafter may be referred to as R22) and / or tetrafluoroethylene (TFE) and chloromethane (hereinafter may be referred to as R40). And a reaction product obtained by a synthesis reaction involving thermal decomposition.

  Here, examples of pentafluoropropene include 1,2,3,3,3-pentafluoropropene and 1,1,3,3,3-pentafluoropropene. Examples of tetrafluoropropene include 2,3,3,3-tetrafluoropropene (HFO-1234yf). Examples of the trifluoropropene include 3,3,3-trifluoropropene, examples of the difluoroethylene include 1,1-difluoroethylene, and examples of the chlorodifluoroethylene include 1-chloro-2,2-difluoroethylene. . Tetrafluoropropene, trifluoropropene, difluoroethylene, and chlorodifluoroethylene can also contain other isomers.

(Alkane with 1 carbon atom)
The C1-C1 alkane contained in the fluid together with the fluoroolefin is a compound in which at least one hydrogen atom of methane may be substituted with a chlorine atom or a fluorine atom. The number of chlorine atoms in such an alkane having 1 carbon atom is preferably 0 or 1.

  Specific examples of the alkane having 1 carbon include methane, chloromethane, chlorodifluoromethane, and the like.

(Fluid containing fluoroolefin and C1 alkane)
The fluid containing one or more of fluoroolefin and alkane having 1 carbon to be processed in the first embodiment of the present invention may be liquid or gas. The content ratio (molar ratio) between the fluoroolefin and the C 1 alkane in the fluid is not particularly limited, but in terms of the efficiency of the subsequent purification, the total mole content of the fluoro olefin is the C 1 alkane content mole. It is preferred that it be greater than the total amount.

  The content of water in the fluid is preferably 10% by mass or less, and more preferably 5% by mass or less. The fluid may contain even a small amount of fluoroolefin and alkane having 1 carbon, but the total content of fluoroolefin and alkane having 1 carbon is preferably 5% by mass or more, and more preferably 10% by mass or more. preferable.

  Further, at least one of the fluoroolefin and the C 1 alkane is preferably produced by a synthetic reaction involving thermal decomposition (hereinafter, sometimes referred to as thermal decomposition / synthetic reaction). More preferably, both of the alkanes having 1 carbon are those produced by a pyrolysis / synthesis reaction. That is, in the production process of fluoroolefin by pyrolysis / synthesis reaction as exemplified below, when the reaction product contains the alkane having 1 carbon atom together with the fluoroolefin, the reaction product of the present invention is used as it is. The contained water can be removed as the starting fluid in the first embodiment. More specifically, the outlet gas obtained by the method for producing HFO-1234yf, which will be described later, is used as it is as a starting fluid, and the water in the fluid is removed, so that a high-purity HFO-1234yf is obtained through a subsequent purification step. Can be obtained.

(Synthetic zeolite)
The synthetic zeolite 3A used in the first embodiment of the present invention refers to a synthetic zeolite having a pore diameter of 0.28 ± 0.03 nm. However, due to the expansion and contraction and kinetic energy of the molecules entering the cavity at the normal operating temperature, this synthetic zeolite 3A can pass molecules having an effective diameter of 0.3 nm.
The synthetic zeolite 3A is a synthetic zeolite having a chemical composition represented by the following chemical formula (1).
K _x Na _y [(AlO ₂ ) ₁₂ (SiO ₂ ) ₁₂ ] · 27H ₂ O (1)
(Here, x + y = 12, and x: y = 4: 6 to 8: 2)

  In the case where the synthetic zeolite has a pore diameter larger than the above range, for example, in the case of synthetic zeolite 4A having a pore diameter of 0.35 ± 0.03 nm, moisture is removed from the fluid containing the fluoroolefin and the alkane having 1 carbon atom. It also adsorbs alkanes having 1 carbon that can be separately separated and used for the reaction. Therefore, there is a risk of losing components that can be used in the subsequent process from the fluid. Moreover, as a result of the pores of the synthetic zeolite being occupied by alkanes having 1 carbon atom, the moisture adsorption capacity may be reduced. Furthermore, in the case of the synthetic zeolite 5A having a pore diameter of 0.42 ± 0.03 nm, not only alkanes having 1 carbon but also compounds such as olefins having 2 carbons are adsorbed. Risk of losing possible ingredients.

Examples of the synthetic zeolite include those expressed as 3A among the A-type synthetic zeolites. Commercially available products include molecular sieve 3A (trade name of Union Showa). Note that the pore diameter of the molecular sieve 3A can be measured by a constant volume gas adsorption method. Examples of the adsorption gas used in the constant volume gas adsorption method include N ₂ , CO ₂ , CH ₄ , H ₂ and Ar.

  The synthetic zeolite used in the embodiment is preferably heat-treated with a drying gas at 100 to 400 ° C. or heat-treated under reduced pressure before being used for drying a fluid containing a fluoroolefin. Thereby, the zeolite is activated and the water removal efficiency is improved.

(Method of contacting fluid with synthetic zeolite)
In the first embodiment of the present invention, a fluid containing a fluoroolefin and an alkane having 1 carbon atom is brought into contact with the above-described synthetic zeolite to adsorb and remove moisture in the fluid.

  The fluid used when contacting the synthetic zeolite may be gas or liquid. A method for bringing a gaseous mixture into contact with the synthetic zeolite as a fluid will be described below. In this method, for example, an adsorption layer filled with synthetic zeolite is formed, and the adsorbed layer is brought into contact by flowing a mixed gas containing a fluoroolefin and an alkane having 1 carbon atom. Contact by this method may be a batch type (batch type) or a continuous type.

The packing density of the synthetic zeolite in the adsorption layer is preferably 0.1 g / cm ³ or more, and more preferably 0.25 g / cm ³ or more. If the packing density of the synthetic zeolite is not less than the lower limit value, the packing amount of the synthetic zeolite per unit volume increases, and the processing amount of the mixed gas can be increased, so that the processing efficiency is improved. There may be one adsorption layer or two or more adsorption layers. When there are two or more adsorbing layers, the adsorbing layers may be in parallel or in series.

  The temperature of the adsorption layer at the time of contact is preferably −10 to 70 ° C., more preferably −10 to 30 ° C. If the temperature of the adsorption layer is equal to or higher than the lower limit, the moisture adsorption efficiency of the synthetic zeolite is improved. If the temperature of the adsorption layer is equal to or lower than the upper limit value, less energy is required for cooling, and facilities and the like are simplified.

  The pressure of the mixed gas at the time of contact (absolute pressure, the same applies hereinafter) is preferably 10 to 2000 kPa, and more preferably 100 to 1000 kPa. If the pressure is equal to or higher than the lower limit, moisture adsorption efficiency is improved. If the pressure is below the upper limit, the handling is good and the equipment is simple.

  The contact time between the mixed gas to be circulated through the adsorption layer and the adsorption layer is preferably 1 to 1000 seconds, and more preferably 3 to 300 seconds. If the contact time between the mixed gas and the adsorption layer is equal to or greater than the lower limit value, the moisture removal efficiency is improved. If the contact time between the mixed gas and the adsorption layer is less than or equal to the upper limit value, the adsorption layer used for drying the fluid may be small, so that the facilities and the like are simplified.

In addition, from the viewpoint of water removal efficiency, the amount of water contained in the mixed gas flowing through the adsorption layer is preferably 0.5% by mass or less, and 0.2% by mass with respect to the total amount of synthetic zeolite in the adsorption layer The following is more preferable.
Examples of the reactor used for contacting the mixed gas with the synthetic zeolite include known reactors that can be filled with synthetic zeolite to form an adsorption layer. Examples of the material of the reactor include glass, iron, nickel, an alloy containing these as a main component, and a fluororesin such as tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA).

In the drying method of the first embodiment, the fluid containing the fluoroolefin to be dried and the alkane having 1 carbon is, for example, from a composition containing a compound capable of producing difluorocarbene (F ₂ C :), Mention may be made of products produced by pyrolysis / synthesis reactions. That is, in the production of a fluoroolefin by a pyrolysis / synthesis reaction from a raw material containing a compound capable of producing the carbene, when the reaction product contains the fluoroolefin and an alkane having 1 carbon, the reaction product Can be used as is for drying.
More specifically, high-purity HFO-1234yf can be obtained by using the outlet gas obtained in the production of HFO-1234yf shown below as a starting fluid as it is and removing the contained water.

<Method for producing fluoroolefin>
The fluoroolefin production method according to the second embodiment of the present invention includes a step of drying the fluid containing the fluoroolefin described above. When the fluoroolefin is HFO-1234yf, examples of the method for producing HFO-1234yf include the following methods.

(Method for producing HFO-1234yf)
Using a composition containing chlorodifluoromethane (R22) and chloromethane (R40) as a raw material, HFO-1234yf is produced by thermal decomposition / synthesis reaction. The thermal decomposition / synthesis reaction is performed by mixing R22 and R40 in advance or separately supplying them to the reactor and retaining them in the reactor at a predetermined temperature for a predetermined time. This manufacturing method may be a continuous manufacturing method or a batch manufacturing method. In view of production efficiency, a continuous method is preferred.

The raw material composition containing R22 and R40 generates a reaction mixture containing difluorocarbene (F ₂ C :) and R40 by thermal decomposition and dehydrochlorination reaction in the reactor, and these reaction mixtures are directly added to the reaction. Or through one or more intermediates, it is believed that it is converted to tetrafluoropropene, particularly HFO-1234yf.

The raw material composition used for manufacturing such HFO-1234yf contains R22 and R40. In addition to these two components, the raw material composition is a fluorine-containing compound that can be thermally decomposed in a reactor to generate F ₂ C :, for example, tetrafluoroethylene (TFE), hexafluoropropene (HFP), octafluorocyclobutane. (RC318), chlorotrifluoroethylene (CTFE), trifluoroethylene, hexafluoropropylene oxide (HFPO) can be contained.
In addition, when TFE is contained as a component of the raw material composition, TFE can be used instead of R22, and the use of R22 can be omitted.

  The reaction temperature at the time of subjecting the raw material composition containing R22 and R40 to the thermal decomposition / synthesis reaction is appropriately adjusted so as to increase the reaction rate of the thermal decomposition / synthesis reaction and to obtain HFO-1234yf efficiently.

  The reaction temperature can be adjusted by heating the raw material composition in the reactor. Examples of the heating method include a method of heating the inside of the reactor with a heating means such as an electric heater, a method of heating the raw material composition in the reactor using a heat medium, and the like. In view of easy reaction control, a method of heating using a heat medium is preferred. In that case, a heating means such as an electric heater may be used as an auxiliary.

Each component including R22 and R40 constituting the raw material composition may be introduced into the reactor at room temperature, but in order to improve the reactivity in the reactor, the temperature at the time of introduction into the reactor is set. You may adjust by heating etc. However, since R22 and TFE, which are fluorine-containing compounds capable of generating F ₂ C :, have different temperature ranges suitable for improving the reactivity, it is preferable to perform temperature adjustment separately.

  The heat medium is supplied to the reactor so as to come into contact with the raw material composition in the reactor for a certain period of time. The heat medium is a medium that does not undergo thermal decomposition at the temperature in the reactor, and specifically, is preferably a medium that does not undergo thermal decomposition at a temperature of 100 to 1200 ° C. Examples of the heat medium include one or more gases selected from water vapor, nitrogen, and carbon dioxide. The use of a gas containing 50% by volume or more of water vapor and the balance being nitrogen and / or carbon dioxide is preferred, and the use of a gas consisting essentially of only water vapor (100% by volume) is particularly preferred.

In this production method, HFO-1234yf can be obtained as a component of the outlet gas from the reactor. Examples of compounds other than HFO-1234yf contained in the outlet gas include the following compounds.
<Compound having 1 carbon atom (alkane having 1 carbon atom)>
Methane, chlorodifluoromethane (R22), chloromethane (R40), etc. <Compound having 2 carbon atoms (olefin having 2 carbon atoms)>
Tetrafluoroethylene (TFE), trifluoroethylene, 1,1-difluoroethylene (VdF), chlorotrifluoroethylene (CTFE), 1-chloro-2,2-difluoroethylene, etc. And C3 unsaturated compounds.)>
3,3,3-trifluoropropyne (propylene), (E) -1,2,3,3,3-pentafluoropropene (HFO-1225ye (E)), (Z) -1,2,3,3 , 3-pentafluoropropene (HFO-1225ye (Z)), hexafluoropropene (HFP), 3,3,3-trifluoropropene (HFO-1243zf), etc. <C4-cyclic compound (hereinafter referred to as C4 cyclic compound) >)
Octafluorocyclobutane (RC318) etc.

  In the second embodiment of the present invention, the outlet gas obtained in this way is dried as shown in the first embodiment, and the water is removed to efficiently purify the subsequent fluoroolefin. And a high-purity fluoroolefin can be obtained.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Example]
A gas fluid containing HFO-1234yf and R40 was obtained from a raw material composition composed of R22 and R40 (hereinafter also referred to as raw material gas) as follows.

  R40 was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C. and heated (preheated) to 300 ° C. Further, R22 was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C., and preheated to 300 ° C.

The raw material gas components (R40 and R22) that have been preheated and adjusted to the above temperature and steam (water vapor) heated by an electric furnace set at a furnace temperature of 780 ° C. have a molar ratio of the supply amount of the raw material components ,
R40 / R22 = 33.3 / 66.7 = 0.5
And the molar ratio of the supply amount of water vapor and the entire raw material composition is
Water vapor / (R40 + R22) = 90/10
(R40 / R22 / water vapor = 3.3 / 6.7 / 90)
In this manner, the reactor was supplied to a reactor whose internal pressure (gauge pressure) was 0.04 MPa and whose internal temperature was controlled to 800 ° C. Hereinafter, all the pressures are assumed to be gauge pressures.

  The molar ratio between the supply amount of water vapor and the supply amount of the entire gas supplied to the reactor (hereinafter referred to as the flow rate molar ratio of water vapor) is 90 / (10 + 90) = 0.9 (90%). Become.

  In this way, the flow rate of the source gas (amount of supply per unit time) was controlled so that the residence time of the source gas in the reactor was 0.5 seconds, and the gas was taken out from the outlet of the reactor. At this time, the actually measured value of the reactor internal temperature was 800 ° C., and the actually measured value of the reactor internal pressure was 0.042 MPa.

Next, the gas taken out from the outlet of the reactor is cooled to 100 ° C. or lower, and after collecting steam and acidic liquid and washing with alkali in order, the gas is analyzed by gas chromatography (hereinafter referred to as GC), and the outlet gas. The molar composition (mol%) of the gas component contained in was determined. The molar composition of the outlet gas component thus obtained is referred to as “initial molar composition 1”.
Further, the moisture content of the outlet gas was measured by the Karl-Fisher method using CA-100 manufactured by Mitsubishi Chemical Corporation.

  Next, the initial mole described above was formed on an adsorption layer formed by filling a stainless steel tube having an inner diameter of 48 mm and a length of 500 mm with a granular material of 575 g of synthetic zeolite 3A (Union Showa Co., Ltd., trade name: Molecular Sieve 3A). Reactor outlet gas having composition 1 is 150 mL / min. The gas after passing through the adsorption layer (hereinafter referred to as passing gas) was continuously analyzed by GC. And the molar composition (mol%) of the passage gas 75 minutes after the distribution start was calculated | required. This is referred to as “molar composition after passing through MS3A”. Furthermore, the moisture content of the passing gas was measured in the same manner as the outlet gas described above.

  Next, in order to easily determine the ease of adsorption of each component to the molecular sieve 3A, the “initial value 1” and “MS3A passage” are determined from the “initial molar composition 1” and “molar composition after passing MS3A” of each component. Values ”were determined as shown below, that is, based on the molar composition (mol%) of HFO-1234yf, which is abundant in the outlet gas and hardly adsorbed on the molecular sieve 3A. The ratio of the molar composition of each component (mol% of each component / mol% of HFO-1234yf) was determined before and after passing through the molecular sieve 3A, and was defined as “initial value 1” and “MS3A passed value” of each component. These values are shown in Table 1 together with the moisture content of the outlet gas and the passing gas.

[Comparative Example 1]
The furnace temperature of the heating furnace (electric furnace) for heating water vapor was set to 800 ° C. Otherwise, the reaction was carried out under the same conditions as in the examples. The actually measured value of the temperature in the reactor was 807 ° C.

  Next, the gas taken out from the outlet of the reactor was cooled, recovered with steam and acidic liquid, and washed with alkali in the same manner as in the examples, followed by GC analysis, and the molar composition of the gas components contained in the outlet gas. (Hereinafter referred to as “initial molar composition 2”). Further, the moisture content of the outlet gas was measured in the same manner as in the example.

  Next, the initial mole described above was formed on the adsorption layer formed by filling 585 g of a granular material of synthetic zeolite 4A (product name: Molecular Sieve 4A) into a stainless steel tube having an inner diameter of 48 mm and a length of 500 mm. Reactor outlet gas having composition 2 was added at 150 mL / min. The passing gas was continuously analyzed by GC. Then, the molar composition of the passing gas 65 minutes after the start of circulation (hereinafter referred to as “molar composition after passing through MS4A”) was determined. Furthermore, the moisture content of the passing gas was measured in the same manner as the outlet gas described above.

  Next, from the “initial molar composition 2” and “molar composition after passing through MS4A” of each component, the “initial value 2” and “MS4A passing value”, which are ratios based on the molar composition of HFO-1234yf, are These values obtained in the same manner are shown in Table 1 together with the moisture contents of the outlet gas and the passing gas.

[Comparative Example 2]
TFE was used instead of R22. Moreover, the furnace temperature of the heating furnace (electric furnace) which heats water vapor | steam was set to 750 degreeC. Otherwise, the reaction was carried out under the same conditions as in the examples. The actually measured value of the temperature in the reactor was 807 ° C.

  Next, the gas taken out from the outlet of the reactor was cooled, recovered with steam and acidic liquid, and washed with alkali in the same manner as in the examples, followed by GC analysis, and the molar composition of the gas components contained in the outlet gas. (Hereinafter referred to as “initial molar composition 3”). Further, the moisture content of the outlet gas was measured in the same manner as in the example.

  Next, the initial mole described above was formed on the adsorption layer formed by filling a stainless steel tube having an inner diameter of 48 mm and a length of 500 mm with a granular material 603 g of synthetic zeolite 5A (trade name: Molecular Sieve 5A, manufactured by Union Showa). Reactor outlet gas having composition 3 was added at 150 mL / min. The passing gas was continuously analyzed by GC. Then, the molar composition of the passing gas 75 minutes after the start of distribution (hereinafter referred to as “molar composition after passing MS5A”) was determined. Furthermore, the moisture content of the passing gas was measured in the same manner as the outlet gas described above.

  Next, from the “initial molar composition 3” and “molar composition after passing through MS5A” of each component, “initial value 3” and “MS5A passing value”, which are ratios based on the molar composition of HFO-1234yf, These values obtained in the same manner are shown in Table 1 together with the moisture contents of the outlet gas and the passing gas.

  From Table 1, in the example using the molecular sieve 3A for the moisture removal (drying) of the gas fluid obtained in the production of HFO-1234yf, the composition of the fluid hardly changed before and after passing through the synthetic zeolite. It can be seen that only the amount has decreased significantly.

  On the other hand, in Comparative Example 1 using the molecular sieve 4A, although the water content is reduced, alkane having 1 carbon is also adsorbed and removed. Also in Comparative Example 2 using the molecular sieve 5A, the water content is reduced, but both the alkane having 1 carbon and the unsaturated compound having 2 carbon are adsorbed and removed. In Comparative Examples 1 and 2, not only the target component may be lost from the reaction gas, but also the pores of the synthetic zeolite are occupied by organic substances, resulting in a decrease in the water adsorption capacity of the synthetic zeolite. .

  From the results of such an example, in order to remove only water from a fluid containing a fluoroolefin and a C 1 alkane without losing organic components such as a C 1 alkane, the molecular sieve that is the synthetic zeolite 3A is used. It can be seen that 3A is optimal.

According to the drying method of the present invention, the alkane having 1 carbon atom is lost from the fluid containing the fluoroolefin and the alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom. In addition, only moisture can be removed.
Moreover, according to the manufacturing method of this invention, highly reliable fluoroolefin with high reliability can be obtained by drying the fluid containing an above-described fluoroolefin.

Claims (7)

  Contacting a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom with the synthetic zeolite 3A to remove moisture in the fluid. A method for drying a fluid containing a featured fluoroolefin.   The method for drying a fluid containing a fluoroolefin according to claim 1, wherein the alkane having 1 carbon is methane, chloromethane, or chlorodifluoromethane.   3. The fluoroolefin according to claim 1 or 2, wherein the fluoroolefin is hexafluoropropene, pentafluoropropene, tetrafluoropropene, trifluoropropene, tetrafluoroethylene, trifluoroethylene, difluoroethylene, chlorotrifluoroethylene, or chlorodifluoroethylene. A process for drying a fluid comprising the described fluoroolefin.   The fluoroolefin is hexafluoropropene, 1,2,3,3,3-pentafluoropropene, 1,1,3,3,3-pentafluoropropene, 2,3,3,3-tetrafluoropropene, 3 , 3,3-trifluoropropene, tetrafluoroethylene, trifluoroethylene, 1,1-difluoroethylene, chlorotrifluoroethylene, 1-chloro-2,2-difluoroethylene A method for drying a fluid containing the fluoroolefin according to claim 3. 5. The fluid according to claim 1, wherein the fluid is produced from a composition containing a compound capable of generating difluorocarbene (F ₂ C :) by a synthetic reaction involving thermal decomposition. A method for drying a fluid containing a fluoroolefin.   Contacting a fluid containing a fluoroolefin and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom with the synthetic zeolite 3A to remove moisture in the fluid. A process for producing a fluoroolefin, comprising: Producing a 2,3,3,3-tetrafluoropropene by subjecting a composition containing chlorodifluoromethane and chloromethane to a synthesis reaction involving thermal decomposition in the presence of a heat medium;
A fluid containing 2,3,3,3-tetrafluoropropene obtained in the above step and an alkane having 1 carbon atom in which at least one hydrogen atom may be substituted with a chlorine atom or a fluorine atom is synthesized with a synthetic zeolite 3A. And a step of removing moisture in the fluid by contacting with the fluid, a method for producing 2,3,3,3-tetrafluoropropene.