WO2014080779A1

WO2014080779A1 - Method for producing 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene

Info

Publication number: WO2014080779A1
Application number: PCT/JP2013/080324
Authority: WO
Inventors: 優竹内; 古田　昇二
Original assignee: 旭硝子株式会社
Priority date: 2012-11-22
Filing date: 2013-11-08
Publication date: 2014-05-30
Also published as: JP2016027005A

Abstract

Provided is an economically advantageous method for producing HFO-1234yf, which is a substance useful as a novel cooling medium, with satisfactorily high yield by a one-cycle reaction involving thermal decomposition. Provided is a method for producing 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene, characterized by comprising the steps of: (a) mixing chlorodifluoromethane and/or tetrafluoroethylene with methane in advance and then supplying the mixture to a reactor, or supplying chlorodifluoromethane and/or tetrafluoroethylene and methane separately to the reactor; (b) supplying a heating medium to the reactor; and (c) bringing the chlorodifluoromethane and/or the tetrafluoroethylene and the methane into contact with the heating medium in the reactor to produce 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene.

Description

Process for producing 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene

The present invention relates to a process for producing 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene, and in particular, 2,3,3,3-tetrafluoroethylene in a single reaction from a raw material containing methane. The present invention relates to a process for producing fluoropropene and 1,1-difluoroethylene.

2,3,3,3-tetrafluoropropene (HFO-1234yf) has an ozone depletion coefficient of 0 (zero) and a very low global warming coefficient of 4; In recent years, great expectations have been placed on a new refrigerant to replace 2-tetrafluoroethane (HFC-134a). In the present specification, for halogenated hydrocarbons, the abbreviation of the compound is described in parentheses after the compound name, but in this specification, 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 synthetic 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.

In Patent Document 1, a mixture obtained by diluting methane and a hydrochlorocarbon having 2 carbon atoms (for example, 1-chloro-1,2,2,2-tetrafluoroethane) with air is used as a specific metal catalyst such as nickel. A method for producing HFO-1234yf by heating to 600 to 650 ° C. in the presence of benzene is proposed.

In addition, as a method for producing fluorocarbons by a single reaction involving thermal decomposition, Non-Patent Document 1 discloses that a mixture obtained by diluting methane and chlorodifluoromethane with nitrogen is subjected to normal heating such as an electric heater in a reactor. A method of obtaining 1,1-difluoroethylene (VdF) industrially useful as a fluororesin raw material by heating and decomposing to a temperature of 400 to 800 ° C. by means is proposed.

However, the method disclosed in Patent Document 1 has a problem in that it is necessary to prepare a special metal catalyst, which complicates the process, and that many hydrochlorocarbons that are raw materials are difficult to obtain.

Non-Patent Document 1 presents a method for obtaining 1,1-difluoroethylene (VdF) using methane and chlorodifluoromethane, which are easily available. In this method, HFO-1234yf is used for the production of HFO-1234yf. It was not reached.

US Patent No. 7951982

The present invention has been made from the above viewpoint, and it is possible to sufficiently control industrially useful HFO-1234yf and VdF in one reaction step involving thermal decomposition, using raw materials that are easily procured. It is an object to provide an economically advantageous process for producing in a state and efficiently.

The present invention includes (a) chlorodifluoromethane (R22) and / or tetrafluoroethylene (TFE) and methane, which are mixed in advance or separately supplied to the reactor, and (b) a heat medium. Supplying to the reactor; and (c) bringing the heat medium into contact with the R22 and / or the TFE and the methane in the reactor, and 2,3,3,3-tetrafluoropropene (HFO- 1234yf) and 1,1-difluoroethylene (VdF),
A method for producing HFO-1234yf and VdF is provided.

According to the production method of the present invention, industrially useful HFO-1234yf and VdF are produced by reacting R22 and / or TFE, which can be easily procured, with methane as a raw material without taking out the intermediate product from the reaction system. Can be manufactured efficiently. Therefore, for example, compared with a method of manufacturing HFO-1234yf using HCFC-225ca as a raw material via CFO-1214ya, the cost required for the raw material and manufacturing equipment can be greatly reduced.

In addition, according to the production method of the present invention, the production (reaction) conditions can be easily controlled, and thus quantitative HFO-1234yf and VdF can be produced, resulting in great economic merit. Furthermore, it is possible to recycle by-products, which has a great economic effect.

It is a figure which shows an example of the reaction apparatus used for the manufacturing method of this invention. It is a figure which shows another example of the reaction apparatus used for the manufacturing method of this invention.

Embodiments of the present invention will be described below.
The present invention uses, as a raw material, at least one of chlorodifluoromethane (R22) and tetrafluoroethylene (TFE) and methane, and in the presence of a heat medium, by a synthetic reaction involving thermal decomposition, HFO-1234yf and VdF A method of manufacturing the same is provided. And this manufacturing method
(A) mixing the R22 and / or the TFE and the methane in advance or separately supplying them to the reactor;
(B) supplying a heat medium to the reactor;
(C) contacting the heating medium with the R22 and / or the TFE and the methane in the reactor to generate the HFO-1234yf and the VdF.

The production method of the present invention may be a continuous production method or a batch production method. In the continuous production method, supply of a raw material containing R22 and / or TFE and methane to a reactor, supply of a heating medium to a reactor, and the reactor of a reaction mixture containing HFO-1234yf and VdF The removal from is performed continuously. In batch-type production, either the supply of the raw material in the step (a) or the supply of the heat medium in the step (b) may be earlier or at the same time. That is, when one of the raw material and the heat medium is supplied, even if the other is not supplied into the reactor, the component supplied later is retained during the retention of the previously supplied raw material or the heat medium. The raw material and the heat medium that are supplied may be in contact with each other for a predetermined time in the reactor. From the viewpoint of reducing the possibility of carbonization of the raw material components when starting the raw material supply to the reactor, it is preferable that the heat medium that is also a dilution gas is supplied into the reactor first.

The production method of the present invention is preferably a continuous method in terms of production efficiency. Hereinafter, an embodiment in which the method of the present invention is applied to continuous production will be described unless otherwise specified as a batch type, but is not limited to a continuous type.

<Production reaction of HFO-1234yf>
In the present invention, when the raw material contains both R22 and TFE and methane, a synthesis reaction involving thermal decomposition and dehydrochlorination shown in the following formula (1) occurs in the reactor, and HFO-1234yf and VdF Produces.
Note that when the raw material does not contain both R22 and TFE but contains only one component, the same reaction occurs, and HFO-1234yf and VdF are generated.

The raw material containing R22 and / or TFE and methane is thermally decomposed and dehydrochlorinated in the reactor to produce a mixture containing difluorocarbene (F ₂ C :) and TFE and methane, which is directly It is considered that it is converted to tetrafluoropropene (particularly HFO-1234yf) or VdF through an addition reaction or through one or more intermediates. In the present invention, these thermal decomposition reactions to the purification reaction of HFO-1234yf and VdF are referred to as synthesis reactions involving thermal decomposition.

<Raw material>
The production of HFO-1234yf and VdF of the present invention uses at least one of R22 and TFE and methane as raw materials. In addition to the two or three components, the raw material is a compound that can be decomposed by contact with a heat medium in the reactor to generate difluorocarbene (F ₂ C :), such as hexafluoropropene (hereinafter referred to as HFP). ), CTFE, trifluoroethylene, octafluorocyclobutane (hereinafter referred to as RC318), hexafluoropropene oxide, and the like.
Hereinafter, fluorine compounds other than R22 and TFE that can be thermally decomposed in a reactor to generate F ₂ C: are referred to as “HFP and the like”.

The molar ratio of the supply amount of methane, which is one of the raw material components, and the total supply amount of R22 and TFE (hereinafter referred to as methane / (R22 + TFE)) should be in the range of 0.01 to 10. preferable. A range of 0.2 to 5 is more preferable, and a range of 0.25 to 4 is particularly preferable. By setting methane / (R22 + TFE) to 0.01 to 10, the conversion of methane can be increased and HFO-1234yf can be produced in high yield.
When the raw material contains only one component of R22 and TFE, the supply amount of the other component is set to 0 (zero), and the supply amount of methane is adjusted so as to be in the above range. In the embodiment of continuous production in which the raw material and the heat medium are continuously circulated in the reactor to perform the reaction, the supply amount of each component of the raw material and the heat medium indicates the supply amount per unit time. And

The molar ratio between the TFE supply amount and the sum of the R22 and TFE supply amounts (hereinafter referred to as TFE / (R22 + TFE)) can be in the range of 0 to 1, but from the viewpoint of economy and safety Therefore, the range of 0 to 0.8 is more preferable, and the range of 0 to 0.5 is particularly preferable.

The temperature of R22 and TFE supplied to the reactor is preferably 0 to 600 ° C. from the viewpoint of making the temperature somewhat reactive but difficult to carbonize. When HFP or the like is supplied together with R22 and / or TFE, the temperature is preferably 0 to 600 ° C.

From the viewpoint of further increasing the reactivity, R22, TFE, HFP, and the like are preferably heated to room temperature (25 ° C.) or higher and 600 ° C. or lower before being introduced into the reactor, and heated to 100 to 500 ° C. Is more preferable.

The temperature of methane supplied to the reactor is preferably 0 to 1200 ° C. from the viewpoint of reactivity. From the viewpoint of further increasing the reactivity, methane is preferably heated to normal temperature (25 ° C.) or higher and 1200 ° C. or lower, more preferably 100 to 800 ° C. before being introduced into the reactor.

Feeding to the reactor such as R22 and / or TFE as raw material components, methane, and HFP used as necessary may be separate, or may be fed after mixing each component. . When supplying the components after mixing them, divide the raw materials into groups, for example, fluorinated compounds and other components, mix each component in each group, and supply each component separately to the reactor Alternatively, all components may be mixed and then supplied. In consideration of the difference in the supply temperature, R22, TFE, HFP, and the like are mixed, adjusted to the preferred temperature and supplied to the reactor, and separately from this, methane is adjusted to the preferred temperature and supplied to the reactor. It is preferable to supply.

When raw material components such as R22 and / or TFE, methane, and HFP used as needed are mixed in advance and then supplied to the reactor, decomposition and reaction proceed before the reactor. From the standpoint of preventing this, the temperature at the time of supplying to the reactor is preferably less than 600 ° C, and particularly preferably less than 500 ° C.

In addition, since methane reacts only in the presence of R22 and / or TFE, in the case of batch production, after mixing methane and R22 and / or TFE, is the mixed gas supplied to the reactor? Alternatively, it is preferable that R22 and / or TFE is supplied to the reactor before methane is supplied. In the case of such a configuration, the timing of supplying the heat medium to the reactor, which will be described later, is not particularly limited, and after the supply of R22 and / or TFE, before the supply of methane, or after the supply of methane. But you can.

<Heat medium>
The heat medium in the present invention is supplied to the reactor so as to be in contact with the raw material for a certain time in the reactor. The heat medium is a medium that does not undergo thermal decomposition at the temperature in the reactor, and specifically, a medium that does not undergo thermal decomposition at a temperature of 100 to 1200 ° C. is preferable. Examples of the heat medium include one or more gases selected from water vapor, nitrogen, and carbon dioxide, and it is preferable to use a gas that contains 50% by volume or more of water vapor and the balance is nitrogen and / or carbon dioxide. In order to remove HCl generated in the thermal decomposition reaction of the formula (1) as hydrochloric acid, the content ratio of water vapor in the heat medium is preferably 50% by volume or more, and a gas substantially consisting of only water vapor (100% by volume) Use is particularly preferred.

The supply amount of the heat medium is preferably 20 to 98% by volume and more preferably 50 to 95% by volume with respect to the total supply amount of the heat medium and the raw material. By making the ratio of the supply amount of the heat medium with respect to the total supply amount of the heat medium and the raw material 20% by volume or more, the thermal decomposition reaction of the above formula (1) while suppressing the formation of high boilers and carbonization of the raw material The HFO-1234yf and VdF can be produced in a sufficiently high yield. Moreover, since productivity will fall remarkably when the said ratio exceeds 98 volume%, it is not industrially realistic.
The temperature of the heat medium supplied to the reactor is preferably 100 to 1200 ° C. from the viewpoint of thermal decomposition and reactivity of raw material components. From the viewpoint of further increasing the reactivity of the raw material components, the temperature of the heat medium introduced into the reactor is more preferably 600 to 900 ° C, and particularly preferably 700 to 900 ° C.

The contact time of the heat medium supplied in this manner with the raw material in the reactor is preferably 0.01 to 10 seconds, and more preferably 0.2 to 3.0 seconds. By setting the contact time to 0.01 to 10 seconds, the production reaction of HFO-1234yf and VdF can sufficiently proceed and the production of by-products can be suppressed. The contact time between the heat medium and the raw material corresponds to the residence time of the raw material in the reactor in the continuous production method, and can be controlled by adjusting the supply amount (flow rate) of the raw material to the reactor.

<Reactor>
The shape of the reactor is not particularly limited as long as it can withstand the temperature and pressure in the reactor described later, and examples thereof include a cylindrical vertical reactor. Examples of the material of the reactor include glass, iron, nickel, or an alloy mainly composed of iron and nickel.

The temperature in the reactor in the step (c) is preferably higher than the supply temperature of R22 and / or TFE and methane, which are raw materials supplied to the reactor, and 400 to 1200 ° C. A range of 600 to 900 ° C. is more preferable, and a range of 710 to 900 ° C. is particularly preferable. By setting the temperature in the reactor to 400 to 1200 ° C., the reaction rate of the production reaction accompanied by thermal decomposition represented by the formula (1) is increased, and HFO-1234yf and VdF can be obtained in a sufficiently high yield. it can.

The temperature in the reactor can be controlled by adjusting the temperature and pressure of the heat medium supplied to the reactor. Further, the inside of the reactor can be supplementarily heated with an electric heater or the like so that the temperature in the reactor falls within a particularly preferable temperature range (710 to 900 ° C.).

The pressure in the reactor is preferably 0 to 2 MPa in gauge pressure, and more preferably in the range of 0 to 0.5 MPa.

<Reactor>
FIG. 1 shows an example of a reaction apparatus used for producing HFO-1234yf and VdF in the present invention.
This reaction apparatus 20 has a reactor 1 provided with heating means such as an electric heater. The reactor 1 includes a methane supply line 2 as a first raw material component, an R22 supply line 3 as a second raw material component, a TFE supply line 4 as a third raw material component, and a steam supply line. 5 are connected as shown below. When only one component of R22 and TFE is supplied, the supply line of the other component is not used. Moreover, installation of the heating means in the reactor 1 is not essential.

The methane supply line 2, the R22 supply line 3 and the TFE supply line 4 are respectively provided with preheaters (preheaters) 2a, 3a and 4a equipped with electric heaters, etc. After being preheated to a predetermined temperature, it is supplied to the reactor 1. The steam supply line 5 is provided with a superheated steam generator 5a, and the temperature and pressure of the steam supplied are adjusted. In addition, installation of the preheater (preheater) 2a, 3a, 4a is not essential.

These raw

material supply lines

2, 3, and 4 may be separately connected to the reactor 1, but as shown in FIG. 2, R22 and TFE in which the raw material supply line 3 and the raw material supply line 4 are connected. A raw material supply line 6 may be connected to the reactor 1. Further, for example, as shown in FIG. 1, after passing through each

preheater

3a, 4a, the R22 supply line 3 and the TFE supply line 4 are connected, and the connected R22 and TFE raw material supply line 6 are connected. The methane supply line 2 after passing through the preheater 2a may be further connected. That is, after preheating R22 and TFE are mixed, preheated methane is further mixed with the raw material mixture of R22 and TFE, and all the raw material components are mixed in this way. It can be configured to be supplied to the reactor 1 from the line 7.
On the other hand, the steam may be supplied to the reactor 1 after being mixed with some or all of the raw materials, but it is preferable to supply the water vapor to the reactor separately from the raw materials. That is, as shown in FIG. 1, it is preferable that the steam is supplied from the steam supply line 5 to the reactor 1 separately from the raw material mixture.

An outlet line 9 provided with a cooling means 8 such as a heat exchanger is connected to the outlet of the reactor 1. In the outlet line 9, a water vapor and acidic liquid recovery tank 10, an alkali cleaning device 11 and a dehydration tower 12 are further installed in this order. Then, after dehydration by the dehydration tower 12, each component of the obtained gas is analyzed and quantified by an analyzer such as gas chromatography (GC).
A gas obtained by removing a reaction mixture containing HFO-1234yf and VdF from the reactor 1 and removing acidic substances such as hydrogen chloride, water vapor, and water by the treatment after the outlet line 9 as described above. Hereinafter referred to as outlet gas.

<Outlet gas component>
In the production method of the present invention, HFO-1234yf and VdF can be obtained as components of the outlet gas. Compounds other than HFO-1234yf and VdF contained in the outlet gas include R22, methane, ethylene, TFE, HFP, CTFE, trifluoroethylene, RC318, 3,3,3-trifluoropropene (CF ₃ CH═CH ₂ : HFO-1243zf) and the like. Among these components, methane and ethylene having a methylene group (= CH ₂ ) or a methyl group (—CH ₃ ) are compounds derived from the raw material component methane, and include TFE, HFP, CTFE, Trifluoroethylene, RC318, and HFO-1243zf are all compounds derived from R22 and / or TFE among the raw material components. HFO-1234yf and VdF are compounds derived from R22 and / or TFE, as well as compounds derived from methane.

The components other than HFO-1234yf and VdF contained in the outlet gas can be removed to a desired extent by known means such as distillation. The separated TFE can be recycled as a part of the raw material. HFP, CTFE, trifluoroethylene, and RC318 are also compounds that can generate a difluorocarbene radical (CF ₂ :), and can be recycled as part of the raw material.

According to the production method of the present invention, using R22 and / or TFE and methane as raw materials, the global warming potential (GWP) is as small as 4 in a single reaction, and HFO-1234yf useful as a new refrigerant is sufficient. In a high yield. For example, the production method of the present invention can not only reduce the cost required for raw materials and production equipment, but also significantly reduce the energy required for production, compared to the conventional method for producing HFO-1234yf. can do. In addition to HFO-1234yf, VdF, which is a raw material for polyvinylidene fluoride, which is industrially used as a water treatment filter, for example, can be manufactured. And can be manufactured simultaneously.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

[Example 1]
Using the reaction apparatus shown in FIG. 1, crude HFO-1234yf and crude VdF were obtained from a raw material gas composed of R22 and methane as follows.

Methane was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C., and the methane was heated to 300 ° C. Moreover, R22 was continuously introduce | transduced into another stainless steel tube in the electric furnace set to 300 degreeC in furnace temperature, and R22 was heated to 300 degreeC.

The amount of raw material components supplied from these raw material gases (methane and R22) preheated and adjusted to the above temperature and steam (water vapor) heated by an electric furnace set at a furnace temperature of 850 ° C. The molar ratio of methane / R22 = 0.5, and the supply ratio of water vapor to the total amount of the raw material gas supply is, in volume%, water vapor / (methane + R22 + water vapor) × 100 = 90%. (Gauge pressure) It was supplied to a reactor controlled at 0.04 MPa and an internal temperature of 800 ° C. Hereinafter, all the pressures are assumed to be gauge pressures.

Thus, the flow rate of the raw material gas (amount supplied per unit time) was controlled so that the residence time of the raw material gas in the reactor was 1.0 second, and the gas of the reaction mixture was taken out from the outlet of the reactor. 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. In addition, the gas of the reaction mixture taken out from the outlet of the reactor includes unreacted source gas in addition to the gas generated or by-produced by the reaction.

Next, the gas of the reaction mixture taken out from the outlet of the reactor is cooled to 100 ° C. or lower, and after performing steam and acidic liquid recovery and alkali washing in order, dehydration treatment is performed, the obtained outlet gas is subjected to gas chromatography. Analysis was performed to calculate the molar composition of the gas component contained in the outlet gas.

Based on the molar composition of the outlet gas thus determined, the conversion rate of methane (reaction rate), the selectivity of each component derived from methane, the conversion rate of R22 (reaction rate), and the selection of each component derived from R22 Each rate was determined. These results are shown in Table 1 together with the reaction conditions. Note that the preheat temperatures of methane and R22 are set temperatures in each preheat electric furnace, and the water vapor temperature is a set temperature in an electric furnace for water vapor heating. The water vapor pressure is a set pressure.

The above values mean the following respectively.
(Methane conversion rate (reaction rate))
When the methane yield is X%, (100-X)% is referred to as methane conversion (reaction rate). It means the ratio (mol%) of reacted methane. The methane yield refers to the proportion (mol%) occupied by methane among the methane-derived components (components having a methylene group or methyl group) in the outlet gas.

(Selectivity of each component derived from methane)
Of the reacted methane, the percentage converted to each component other than methane is the percentage. The selectivity of each component is obtained by “yield of each component derived from methane” / “conversion rate of methane (reaction rate)”. The yield of each component derived from methane refers to the proportion (mol%) of each compound other than methane among the components derived from methane in the outlet gas.

(R22 conversion rate (reaction rate))
When the yield of R22 is X%, (100-X)% is referred to as the conversion rate (reaction rate) of R22. It means the ratio (mol%) of reacted R22. In addition, R22 yield says the ratio (mol%) which R22 accounts among the components derived from R22 (component which has a fluorine atom) in outlet gas.

(Selectivity of each component derived from R22)
Of the reacted R22, the percentage converted to each component other than R22 is the percentage of each. The selectivity of each component is obtained by “yield of each component derived from R22” / “conversion rate (reaction rate) of R22”. In addition, the yield of each component derived from R22 refers to the proportion (mol%) of each compound other than R22 among the components derived from R22 in the outlet gas.

[Examples 2 to 4]
The temperature in the reactor was changed as shown in Table 1. Otherwise, the reaction was carried out under the same conditions as in Example 1. Next, the gas taken out from the outlet of the reactor was treated in the same manner as in Example 1 and then analyzed in the same manner. The results are shown in Table 1 together with the reaction conditions.

[Examples 5 to 7]
The supply ratio of water vapor to the total gas supply amount was changed as shown in Table 2 by volume% (water vapor / (methane + R22 + water vapor) × 100). Otherwise, the reaction was carried out under the same conditions as in Example 1. Subsequently, the gas of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and then analyzed in the same manner. The results are shown in Table 2 together with the reaction conditions.

[Examples 8 to 11]
The molar ratio of methane supply to R22 supply (methane / R22) was changed as shown in Table 3. Otherwise, the reaction was carried out under the same conditions as in Example 1. Subsequently, the gas of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1 and then analyzed in the same manner. The results are shown in Table 3 together with the reaction conditions.

[Examples 12 to 14]
The pressure in the reactor was changed as shown in Table 4. Otherwise, the reaction was carried out under the same conditions as in Example 1. Subsequently, the gas of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and then analyzed in the same manner. The results are shown in Table 4 together with the reaction conditions.

[Examples 15 to 19]
The residence time in the reactor was changed as shown in Table 5. Otherwise, the reaction was performed under the same conditions as in Example 1. Subsequently, the gas of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and then analyzed in the same manner. The results are shown in Table 5 together with the reaction conditions.

As can be seen from Tables 1 to 5, in any of Examples 1 to 19, the total selectivity of methane-derived HFO-1234yf and VdF in the outlet gas was as high as 80% or more. Yes. In addition, since the selectivity of TFE derived from R22 is high, it can be seen that most of R22 not involved in the reaction with methane is converted to TFE by the homocoupling reaction between R22.

In addition, the following can be seen from Tables 1 to 5.
That is, it can be seen from Table 1 that the conversion rate of methane increases as the reaction temperature increases.
From Table 2, it can be seen that when the proportion of water vapor decreases, the selectivity of R22 to TFE decreases.
From Table 3, it can be seen that as (methane / R22) decreases, the selectivity of methane-derived HFO-1234yf increases and the selectivity of methane-derived VdF decreases. From this, it can be seen that it is possible to balance the co-production of HFO-1234yf and VdF within a predetermined range of (methane / R22).
From Table 4, it can be seen that the total selectivity of methane-derived HFO-1234yf and VdF is as high as 89% or more regardless of the pressure in the reactor. Incidentally, an increase in pressure in the gas phase reaction means a substantial increase in production capacity.

Furthermore, it can be seen from Table 5 that when the residence time is increased, the conversion rate of R22 reaches a peak at 92%, but the conversion rate of methane is greatly improved. This can be considered because the component produced by the conversion of R22 reacts with methane. In this reaction, the compound that is considered to react with methane is considered to be TFE whose molar fraction decreases from the outlet gas component with an increase in residence time.
From the above consideration, in Examples 20 to 25 below, TFE was used as a raw material component.

[Example 20]
Using the same reaction apparatus as in Example 1, crude HFO-1234yf and crude VdF were obtained from a raw material gas composed of TFE and methane as shown below.

Methane was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C., and the methane was heated to 300 ° C. Moreover, TFE was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and TFE was heated to 300 degreeC.

Thus, these raw material gases (methane and TFE) that have been preheated and adjusted to the above temperature and water vapor that has been heated by an electric furnace set at a furnace temperature of 850 ° C. are used as moles of the supply amount of the raw material components. The ratio is methane / TFE = 1.0, and the ratio of the supply amount of water vapor to the total gas supply amount is volume%, and water vapor / (methane + TFE + water vapor) × 100 = 90%. The gauge pressure was supplied to a reactor controlled at 0.04 MPa and an internal temperature of 800 ° C.

Thus, the flow rate of the source gas (amount supplied per unit time) was controlled so that the residence time of the source gas in the reactor was 1 second, and the gas of the reaction mixture was taken out from the outlet of the reactor. 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 of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and the molar composition of the gas components contained in the outlet gas was calculated in the same manner. Based on the molar composition of the outlet gas thus obtained, the conversion rate of methane (reaction rate), the selectivity of each component derived from methane, the conversion rate of TFE (reaction rate), the selection of each component derived from TFE Each rate was determined. These results are shown in Table 6 together with the reaction conditions.
Note that the methane and TFE preheat temperatures are set temperatures in each preheating electric furnace, and the water vapor temperature is a set temperature in the water vapor heating electric furnace. The water vapor pressure is a set pressure.

The conversion rate (reaction rate) of TFE and the selectivity of each component derived from TFE mean the following.

(TFE conversion rate (reaction rate))
When the TFE yield is X%, (100-X)% is referred to as TFE conversion (reaction rate). It means the ratio (mol%) of reacted TFE. The TFE yield refers to the proportion (mol%) occupied by TFE in the TFE-derived component (component having a fluoro group) in the outlet gas.

(Selectivity of each component derived from TFE)
Of the reacted TFE, the percentage converted to each component other than TFE is the percentage of each. The selectivity of each component is determined by “yield of each component derived from TFE” / “conversion rate of TFE (reaction rate)”. In addition, the yield of each component derived from TFE refers to the ratio (mol%) of each compound other than TFE among the TFE-derived components in the outlet gas.

[Example 21]
Using the same reactor as in Example 1 except that there are three raw material supply lines, crude HFO-1234yf and crude VdF are obtained from the raw material composition comprising R22, methane and TFE as shown below. It was.

Methane was continuously introduced into a stainless steel tube in an electric furnace set to a furnace temperature of 300 ° C., and the methane was heated to 300 ° C. (preheating). Moreover, R22 was continuously introduce | transduced into the stainless steel tube in the electric furnace set to 300 degreeC in furnace temperature, and R22 was preheated to 300 degreeC. Furthermore, TFE was continuously introduced into the stainless steel tube in the electric furnace set to a furnace temperature of 300 ° C., and the TFE was preheated to 300 ° C.

The molar ratio of the supply amount of the raw material components of these raw material gas components (methane, R22 and TFE) preheated in this way and the steam heated by the electric furnace set at a furnace temperature of 850 ° C.
TFE / R22 = 1 (ie, TFE / (TFE + R22) = 0.5)
Methane / (R22 + TFE) = 0.75
And the ratio of water vapor supply to the total gas supply is vol%, water vapor / (methane + R22 + TFE + water vapor) × 100 = 90%, and the internal pressure (gauge pressure) is 0.04 MPa and the internal temperature is 800 ° C. Feed to a controlled reactor.

Note that the molar ratio of methane to the total of R22 and TFE (methane / (R22 + TFE) is 0.75 as described above, but among the components constituting the raw material composition, as a compound containing fluorine. From the viewpoint of working, since 1 mole of TFE can be counted as 2 equivalents corresponding to 2 moles of R22, the equivalent ratio of methane to the sum of R22 and TFE (methane / (R22 + TFE × 2) is 0. 5

Thus, the flow rate of the raw material gas (amount supplied per unit time) was controlled so that the residence time of the raw material gas in the reactor was 1.0 second, and the gas of the reaction mixture was taken out from the outlet of the reactor. 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 of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and the molar composition of the gas components contained in the outlet gas was calculated in the same manner. Based on the molar composition of the outlet gas thus determined, the conversion rate of methane (reaction rate), the selectivity of each component derived from methane, the conversion rate of R22 and / or TFE (reaction rate), R22 and / or Alternatively, the selectivity of each component derived from TFE was determined. These results are shown in Table 7 together with the reaction conditions.
Note that the preheating temperatures of methane, R22, and TFE are set temperatures in each preheating electric furnace, and the water vapor temperature is a setting temperature in an electric furnace for steam heating. The water vapor pressure is a set pressure.

The conversion rate (reaction rate) of R22 and TFE and the selectivity of each component derived from R22 and / or TFE mean the following.

(R22 and / or TFE conversion (reaction rate))
Among the components derived from R22 and / or TFE, which are fluorine-containing compounds in the outlet gas (components having fluorine atoms), the proportion of R22 and / or TFE (R22 and / or TFE recovery rate) is X%. (100-X)% is referred to as the conversion rate (reaction rate) of R22 and / or TFE. It means the ratio (mol%) of reacted R22 and / or TFE.

(Selectivity of each component derived from R22 and / or TFE)
Among the reacted R22 and / or TFE, the percentage obtained as each component other than R22 each means. The selectivity of each component is determined by “yield of each component derived from R22 and / or TFE” / “conversion rate (reaction rate) of R22 and / or TFE”. The yield of each component derived from R22 and / or TFE refers to the proportion (mol%) of each component other than R22 in the components derived from R22 and / or TFE in the outlet gas.

Here, in Examples 21 to 25 containing TFE as a raw material gas, TFE reacts (= converted) but is also generated from R22, so it is impossible to determine the conversion rate (reaction rate) of only TFE. It is. It is also impossible to determine whether the products having fluorine atoms, HFO-1234yf and VdF, are generated from R22 or TFE. Therefore, assuming that “the TFE of the raw material is all R22”, the rate of reaction of the raw material R22 is defined as the conversion rate (reaction rate) of R22 and / or TFE. Further, the percentage of each component converted from the raw material R22 is obtained, and the selectivity of each component derived from R22 and / or TFE is used.

[Examples 22 to 25]
The molar ratio (TFE / (TFE + R22)) of the supply amount of TFE and the total supply amount of TFE and R22 is 0.1 in Example 22, 0.3 in Example 23, and 0.7 in Example 24. In Example 25, it was set to 0.9. In addition, the molar ratio of methane / (TFE + R22) was 0.55 in Example 22 so that the equivalent ratio of methane to the sum of R22 and TFE (methane / (R22 + TFE × 2) was 0.5). Example 23 was 0.65, Example 24 was 0.85, and Example 25 was 0.95. Otherwise, the reaction was performed under the same conditions as in Example 1.

Next, the gas of the reaction mixture taken out from the outlet of the reactor was treated in the same manner as in Example 1, and then the outlet gas was analyzed in the same manner. The results are shown in Table 7 together with the reaction conditions.

As can be seen from Table 6 and Table 7, in all of Examples 20 to 25, the total selectivity of methane-derived HFO-1234yf and VdF in the outlet gas was as high as 80% or more. HFO-1234yf and VdF can be produced by using a raw material composition containing at least one of R22 and TFE and methane.

From these results, it can be said that according to the production method of the present invention, HFO-1234yf and VdF can be obtained efficiently.
In each example of the above reaction conditions, it was confirmed that almost the same results were obtained with good reproducibility in reactions under the same conditions. Thus, according to the production method of the present invention, it is easy to control the reaction conditions, and thus it can be said that quantitative production of HFO-1234yf and VdF is possible.

According to the production method of the present invention, R22 and / or TFE, which can be easily procured, and methane as raw materials are reacted as they are without taking intermediate products from the reaction system, and industrially useful HFO-1234yf and VdF can be produced efficiently. Therefore, for example, compared with a method of manufacturing HFO-1234yf using HCFC-225ca as a raw material via CFO-1214ya, the cost required for the raw material and manufacturing equipment can be greatly reduced.

In addition, according to the production method of the present invention, the production (reaction) conditions can be easily controlled, so that quantitative production of HFO-1234yf and VdF is possible, resulting in great economic merit. Furthermore, it is possible to recycle by-products, which has a great economic effect.
The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2012-256211, filed on November 22, 2012 are cited herein as disclosure of the specification of the present invention. Incorporated.

DESCRIPTION OF SYMBOLS 1 ... Reactor, 2 ... Methane supply line, 3 ... R22 supply line, 4 ... TFE supply line, 5 ... Steam supply line, 2a, 3a, 4a ... Preheater (preheater), 5a ... Superheated steam generation 7 ... Raw material mixing supply line, 8 ... Cooling means, 9 ... Outlet line, 10 ... Steam and acidic liquid recovery tank, 11 ... Alkaline washing device, 12 ... Dehydration tower, 20 ... Reactor.

Claims

(A) chlorodifluoromethane and / or tetrafluoroethylene and methane are mixed in advance or supplied separately to the reactor;
(B) supplying a heat medium to the reactor;
(C) bringing the heat medium into contact with the chlorodifluoromethane and / or the tetrafluoroethylene and the methane in the reactor, thereby obtaining 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene. A step of generating,
A process for producing 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene, wherein
The 2, 3, 3 according to claim 1, wherein methane is supplied to the reactor at a ratio of 0.01 to 10 mol of the methane with respect to 1 mol of the total of the chlorodifluoromethane and the tetrafluoroethylene. Of 1,3-tetrafluoropropene and 1,1-difluoroethylene.
The tetrafluoroethylene is fed to the reactor at a ratio of 0 to 0.8 mol of the tetrafluoroethylene with respect to 1 mol of the total of the chlorodifluoromethane and the tetrafluoroethylene. Of 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene according to any one of claims 1 to 3, wherein the temperature of the methane supplied to the reactor is 0 to 1200 ° C. Production method.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoro according to any one of claims 1 to 4, wherein the temperature of the chlorodifluoromethane fed to the reactor is 0 to 600 ° C. A method for producing ethylene.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoro according to any one of claims 1 to 5, wherein the temperature of the tetrafluoroethylene fed to the reactor is 0 to 600 ° C. A method for producing ethylene.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoro according to any one of claims 1 to 6, wherein the temperature in the reactor in step (c) is adjusted to 400 to 1200 ° C. A method for producing ethylene.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoroethylene according to any one of claims 1 to 7, wherein the temperature of the heating medium supplied to the reactor is 100 to 1200 ° C. Manufacturing method.
The 2,3,3,3-tetrafluoropropene and 1,1-difluoro according to any one of claims 1 to 8, wherein the heat medium comprises one or more selected from water vapor, nitrogen and carbon dioxide. A method for producing ethylene.
The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 9, wherein the supply amount of the heat medium is 20 to 98% by volume in the total gas supplied to the reactor. And a method for producing 1,1-difluoroethylene.
The 2,3,3,3-tetrafluoro according to any one of claims 1 to 10, wherein a contact time of the gas supplied to the reactor in the reactor is 0.01 to 10 seconds. A process for producing propene and 1,1-difluoroethylene.