JP2014129260A - Method for producing 2,3,3,3-tetrafluoropropene - Google Patents

Abstract

An economically advantageous method for producing industrially useful HFO-1234yf in a well-controlled and efficient manner by a single reaction involving thermal decomposition using raw materials that are easily procured. provide.
A method for producing HFO-1234yf by a synthesis reaction involving thermal decomposition, using a first raw material composition containing R22 and a second raw material composition containing R40 and / or R50, comprising: ) Supplying and contacting the first raw material composition and the first heat medium into the first reactor to bring the first raw material composition to the first temperature in the range of 0 to 850 ° C. And (b) supplying and contacting the second raw material composition and the second heat medium in the second reactor, and bringing the second raw material composition to 600 to 900 ° C. Obtaining a second mixture at a second temperature in the range, and (c) supplying and contacting the first mixture and the second mixture in a third reactor. And
[Selection] Figure 1

Description

  The present invention relates to a method for producing 2,3,3,3-tetrafluoropropene, and in particular, 2,3,3,3-tetrafluoropropene is produced from chlorodifluoromethane and chloromethane and / or methane. On how to do.

  In recent years, 2,3,3,3-tetrafluoropropene (HFO-1234yf) has been highly expected as a new refrigerant to replace 1,1,1,2-tetrafluoroethane (HFC-134a), which is a greenhouse gas. It has been. 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 such HFO-1234yf, for example, 1,1-dichloro-2,2,3,3,3-pentafluoropropane (HCFC-225ca) is removed 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 hydrogen fluoride is used as a synthetic raw material and reduced by hydrogen.

  However, such a method has a problem that the equipment cost increases because of the multi-stage reaction, and it is difficult to distill and purify the intermediate product and the final product. In order to solve such a problem, a method for producing HFO-1234yf from a raw material containing chlorocarbons by a single reaction involving thermal decomposition has been proposed.

For example, in Patent Document 1, chloromethane (R40) and chlorodifluoromethane (R22) are combined, heated to 845 ± 5 ° C. in the presence of water vapor, dehydrochlorinated and condensed, and 1,1- A method for producing difluoroethylene (VdF) as a main product is described, and it is proposed that fluorine-containing olefins such as HFO-1234yf are produced as by-products.
Further, in Patent Document 2, a mixture of R40 and tetrafluoroethylene (TFE) or R22 is heated and decomposed to a temperature of 700 to 950 ° C. by a normal heating means such as an electric heater in a reactor, A method for obtaining HFO-1234yf is presented.

  However, in the above-described method described in Patent Document 1, VdF is obtained in a high yield because VdF is set as a target substance, but HFO-1234yf cannot be efficiently produced. .

  In addition, in the method disclosed in Patent Document 2, with the increase in residence time, there is a possibility that the production of high-boilers as by-products and carbonization of raw materials occur, the reactor may be clogged, and the by-product acid is generated. Because of this, special anti-corrosion equipment (reaction tubes lined with platinum, etc.) is necessary, which is not practical at all when considering industrial production.

Japanese Examined Patent Publication No. 40-2132 (Example 4) U.S. Pat. No. 2,931,840

  The present invention has been made from the above viewpoint, and is an economically and efficiently produced HFO-1234yf that is useful as a new refrigerant by a reaction involving thermal decomposition, using raw materials that are easily procured. It is an object to provide a particularly advantageous method.

The present invention uses a first raw material composition containing chlorodifluoromethane (R22) and a second raw material composition containing chloromethane (R40) and / or methane (R50), and a synthetic reaction involving thermal decomposition. A process for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) by:
(A) Supplying and contacting the first raw material composition and the first heat medium in a first reactor, and bringing the first raw material composition into a first temperature in the range of 0 to 850 ° C. Obtaining a first mixture; and
(B) supplying and contacting the second raw material composition and the second heat medium into the second reactor, and bringing the second raw material composition into a second temperature in the range of 600 to 900 ° C. Obtaining a second mixture, and
(C) Supplying and bringing the first mixture obtained in the step (a) and the second mixture obtained in the step (b) into contact with each other in the third reactor. A method for producing HFO-1234yf is provided.

  In the present invention, the “first mixture” refers to a mixture of all components obtained by the reaction of the first raw material composition in the step (a) and existing in the first reactor. Specifically, , A mixture of chemical species (including intermediate active species 1 and 2 described later) generated by the reaction of the first raw material composition, unreacted raw material components, and the first heat medium. The “second mixture” refers to a mixture of all components obtained by the reaction of the second raw material composition in step (b) and present in the second reactor. 2 refers to a mixture of chemical species (including intermediate active species 3 described later) generated by the reaction of the raw material composition 2, unreacted raw material components, and a second heat medium. The first mixture and the second mixture will be described in more detail below.

  According to the production method of the present invention, R22 and R40 and / or R50 which are easy to procure are used as raw materials, and these raw materials are divided into two groups: a compound containing a fluorine atom and a compound containing no fluorine atom. An industrially useful HFO-1234yf is obtained by generating desired intermediate active species under optimum temperature conditions for each group, and then bringing these intermediate active species into contact with each other without removing them from the reaction system. Can be efficiently manufactured in a sufficiently controlled state. Therefore, compared with a conventionally known method for producing HFO-1234yf, the cost required for raw materials and production equipment can be greatly reduced.

  Further, according to the production method of the present invention, the reaction can be carried out in the presence of a heat medium, so that the formation of high-boiling substances can be greatly suppressed, and the production (reaction) conditions can be easily controlled. HFO-1234yf can be manufactured with great economic merit. Specifically, in a synthesis reaction involving thermal decomposition using R22 and R40 and / or R50 as a raw material, the proportion of HFO-1234yf in the reaction product tends to be high in the reaction product. It is economically advantageous in that the relative relationship with VdF can be a certain value or more. 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. 10 is a diagram showing an example of a reaction apparatus used in Example 5. FIG.

Embodiments of the present invention will be described below.
The present invention provides a method for producing HFO-1234yf by a synthesis reaction involving thermal decomposition, using a first raw material composition containing R22 and a second raw material composition containing R40 and / or R50. And this manufacturing method, as detailed below,
(A) Supplying and contacting the first raw material composition and the first heat medium in a first reactor, and bringing the first raw material composition into a first temperature in the range of 0 to 850 ° C. Obtaining a first mixture; and
(B) supplying and contacting the second raw material composition and the second heat medium into the second reactor, and bringing the second raw material composition into a second temperature in the range of 600 to 900 ° C. Obtaining a second mixture, and
(C) In the third reactor, the step of supplying and contacting the first mixture obtained in the step (a) and the second mixture obtained in the step (b) .

  A reaction system for synthesizing HFO-1234yf by a synthesis reaction accompanied by thermal decomposition using R22 and R40 and / or R50 as raw materials with reference to the following formula (1). Will be explained.

  In the formula (1), the part surrounded by the frame (A) indicates chemical species generated by thermal decomposition of R22 or the like. That is, difluorocarbene (intermediate active species 1) obtained by dehydrogenation of R22 is produced from R22 by heating, and TFE is produced by homocoupling of intermediate active species 1. In addition, it is assumed that trifluoromethyl fluorocarbene (intermediate active species 2) is generated by the transfer of fluorine from TFE.

  On the other hand, in the formula (1), the chemical species generated by the thermal decomposition reaction of R40 and / or R50 is shown in the part surrounded by the frame (B). R40 and R50 are considered to generate a methyl radical (intermediate active species 3) in which chlorine and hydrogen are radically cleaved by heating, respectively.

  Then, difluorocarbene (intermediate active species 1) and trifluoromethyl fluorocarbene (intermediate active species 2) obtained from R22 and a methyl radical (intermediate active species 3) obtained from R40 and / or R50 are bonded to each other. It is considered that active species 4 and intermediate active species 5 are produced, and each of the obtained intermediate active species undergoes a dehydrogenation radical reaction to produce HFO-1234yf and VdF. In the above formula (1), the route A represents a reaction route for producing HFO-1234yf, and the route B represents a reaction route for producing VdF.

  Here, the path A for generating HFO-1234yf and the path B for generating VdF are competing, and by causing the path A to proceed preferentially, HFO-1234yf is converted into the reaction system represented by the above formula (1). It becomes possible to manufacture efficiently.

  Usually, in such a pyrolysis reaction, raw materials, that is, R22, R40 and / or R50 are simultaneously supplied to one reactor, and the above-described reactions are performed almost simultaneously. Therefore, in the reaction system shown in Formula (1), there is a limit to the method for changing the reaction conditions in order to preferentially perform the route A over the route B. In particular, regarding the temperature conditions, it is not possible to set the individual reactions to the optimum temperatures.

  Therefore, in the production method of the present invention, the reaction in the frame (A) in the above formula (1) is carried out in the first reactor using the first heat medium in the step (a), and the frame is similarly applied. The reaction in (B) is carried out in the second reactor using the second heat medium in the step (b), and further in the step (c), in the step (a) in the first reactor. All the components obtained (including the first heat medium) are fed into the third reactor as a first mixture, and all the components obtained in the second reactor in step (b) (Including the second heat medium) is fed into the third reactor as the second mixture, and the reaction in the frame (C) showing the entire formula (1) in the third reactor. It was decided to let Then, by setting the temperature conditions in the steps (a) and (b) to the optimum temperature in each step, that is, the temperature range shown above, in the step (c), the generation of HFO-1234yf by the path A is It is possible to prioritize the generation of VdF by the path B.

  In the present invention, by such a method, the ratio of HFO-1234yf in the finally obtained reaction product can be increased as a relative ratio with VdF. Hereinafter, the content ratio of HFO-1234yf and VdF in the reaction product is expressed as “HFO-1234yf / VdF” as a molar ratio, as a molar amount of HFO-1234yf / a molar amount of VdF. As will be described later, in the reaction system represented by the above formula (1), when the obtained by-products are returned to the reaction system and recycled, the utilization efficiency of raw material components increases, and as a result, the production efficiency of HFO-1234yf increases. be able to. However, the present inventors have confirmed that even if VdF is returned to the reaction system, it hardly leads to improvement in the productivity of HFO-1234yf. Therefore, using HFO-1234yf / VdF as an index, a production method in which this value is high is considered to be economically superior as a method for producing HFO-1234yf.

  The production method of the present invention may be a continuous production method or a batch production method. In the continuous production method, the supply of the first raw material composition containing R22 in step (a) to the first reactor and the supply of the first heat medium to the first reactor are as follows. Each of the raw material compositions is carried out simultaneously and continuously under conditions that allow the temperature of the raw material composition to fall within the first temperature range. And the supply to the 3rd reactor of such a (a) process and the 1st mixture obtained in the 1st reactor in the (a) process is also performed continuously. In step (b), the second raw material composition containing R40 and / or R50 is supplied to the second reactor, and the second heat medium is supplied to the second reactor. The conditions are such that the temperature of the raw material composition can be within the range of the second temperature, and they are performed simultaneously and continuously, and are obtained in the second reactor in steps (b) and (b). Feeding the second mixture thus obtained to the third reactor is also carried out continuously.

  In the batch type production method, either the first raw material composition supply or the first heat medium supply in the step (a) may be earlier or at the same time. That is, when one of the first raw material composition and the first heating medium is supplied, even if the other is not supplied into the first reactor, the first raw material composition supplied first is supplied. The component to be supplied later is supplied while the product or the first heat medium stays in the first reactor, and the first raw material composition and the first heat medium are supplied in the first reactor. It is sufficient that the temperature of the first raw material composition falls within the range of the first temperature in contact. Similarly, in the step (b), the second raw material composition and the second heat medium are supplied in such a manner that the second raw material composition and the second heat medium are in the second reactor. As long as it comes into contact and the temperature of the second raw material composition falls within the range of the second temperature, whichever may be earlier or simultaneously.

  Further, in the batch type production method, in the step (c), the first mixture obtained in the step (a) is supplied to the third reactor, and the second mixture obtained in the step (b) is used. The feed of the mixture to the third reactor may be either first or simultaneously. That is, when one of the first mixture and the second mixture is supplied, even if the other is not supplied into the third reactor, the first mixture or the second mixture supplied previously While the mixture is staying in the third reactor, the mixture supplied later is supplied, and the first mixture and the second mixture may stay in the third reactor for a predetermined time.

  The production method of the present invention is preferably a continuous method in terms of production efficiency. Hereinafter, although embodiment which applies the method of this invention to continuous manufacture is described, it is not limited to this.

<(A) Process>
In the step (a) of the present invention, the first raw material composition containing R22 is supplied to the first reactor, and the first heat medium is supplied to the first reactor. Then, the first heat medium is brought into contact with the first raw material composition in the first reactor to bring the first raw material composition to the first temperature in the range of 0 to 850 ° C. In the step (a), the reaction surrounded by the frame (A) in the formula (1) is performed separately from the other reactions in the first reactor. Hereinafter, the reaction surrounded by the frame (A) is referred to as the reaction in the step (a) as necessary. The first temperature is preferably in the range of 500 to 850 ° C, more preferably in the range of 500 to 800 ° C, and particularly preferably in the range of 400 to 750 ° C.

  The first raw material composition containing R22 is heated and maintained at the first temperature in the above range in contact with the first heat medium in the first reactor. Then, a first gas containing difluorocarbene (intermediate active species 1), TFE, trifluoromethyl fluorocarbene (intermediate active species 2) and unreacted raw material R22 produced by thermal decomposition, dehydrochlorination reaction, and fluorine transfer. It is thought to produce a reaction product. In addition, the mixture of the first reaction product and the first heat medium becomes the first mixture obtained in the step (a).

  In the first mixture obtained by the step (a), it is preferable that the proportion of trifluoromethylfluorocarbene (intermediate active species 2) is higher than that of difluorocarbene (intermediate active species 1). Thereby, in the next step (c), the reaction of the route A in the above formula (1) proceeds in preference to the reaction of the route B to increase the value of HFO-1234yf / VdF, that is, production of HFO-1234yf Efficiency can be increased. Specific methods, conditions, and the like for increasing the abundance ratio of trifluoromethylfluorocarbene (intermediate active species 2) in the first mixture will be described below.

(First raw material composition)
The first raw material composition used in the step (a) contains R22. Considering the reaction of the step (a) from the number of reaction steps, it can be considered that TFE is used in preference to R22 as the first raw material composition. In the present invention, R22 is used as the first raw material composition in view of ease of procurement, that is, economy. However, the first raw material composition may contain TFE as long as it is economically acceptable.

  Furthermore, in addition to R22, the first raw material composition is a compound that can be decomposed by contact with the first heat medium in the first reactor to generate difluorocarbene or trifluoromethylfluorocarbene, such as hexa Fluoropropene (hereinafter referred to as HFP), trifluoroethylene, octafluorocyclobutane (hereinafter referred to as RC318), hexafluoropropene oxide, and the like can be contained.

  From such a fluorine-containing compound that can be thermally decomposed to generate difluorocarbene contained in the first raw material composition, trifluoromethylfluorocarbene is produced via TFE in the reaction of step (a). The Some of the fluorine-containing compounds directly generate trifluoromethylfluorocarbene by thermal decomposition. If the thermal decomposition reaction occurs in step (a), trifluoromethylfluorocarbene is generated. Then, the obtained trifluoromethyl fluorocarbene reacts with the methyl radical generated in the step (b) in the step (c) described later, and finally, HFO-1234yf is generated.

  When a fluorine-containing compound that can be thermally decomposed in such a reactor to generate difluorocarbene or trifluoromethylfluorocarbene (hereinafter referred to as a fluorine-containing compound that serves as a carbene source) is used as the first raw material composition. Such a fluorine-containing compound may be newly prepared, but is selected from fluorine-containing compounds by-produced by a thermal decomposition reaction in the production method of the present invention, for example, HFP, RC318, trifluoroethylene and the like. It is preferable from the viewpoint of recycling to use one kind or two or more kinds. Among these, RC318 is particularly preferable. Furthermore, the TEE contained in the first mixture can be recovered together with unreacted R22 after the step (c) and used in the first raw material composition, which is particularly preferable from the viewpoint of recycling.

  Here, in the case of using, as the first raw material composition, RFE in addition to R22 and a fluorine-containing compound as another carbene source as described above, R22 in the first raw material composition and The content ratio of the fluorine-containing compound other than is not particularly limited. The content ratio of difluorocarbene and trifluoromethylfluorocarbene in the first mixture obtained by the reaction in the step (a) is the first temperature at which the step (a) is mainly performed regardless of the type of the fluorine-containing compound used. It is thought that it is controlled by.

  In the present embodiment in which the first raw material composition containing R22 and the first heat medium are allowed to react by continuously flowing through the first reactor, the amount of each raw material component and the heat medium supplied Indicates the supply amount per unit time. The same applies to the supply amount of each component, heat medium, etc. in the steps (b) and (c).

The temperature of the first raw material composition supplied to the first reactor is preferably 0 to 600 ° C. from the viewpoint that the reactivity is high to some extent but is not easily carbonized. From the viewpoint of further increasing the reactivity, the first raw material composition is preferably preheated (preheated) to room temperature (25 ° C.) or more and 500 ° C. or less before being introduced into the first reactor. It is more preferable to preheat (preheat) to 500 ° C.
However, the temperature of each component supplied to the first reactor is set to be equal to or lower than the first temperature.

  The supply of R22 and other fluorine-containing compounds or TFE used as necessary carbene sources to the first reactor may be separate or supplied after mixing two or more components. May be. When supplying after mixing 2 or more types of components, it is preferable to supply, after preheating the mixed thing to predetermined temperature from a viewpoint of the efficiency of preheating. In this case, the preheating temperature can be the same as described above.

(First heat medium)
In the step (a), the first raw material composition is brought into contact with the first raw material composition in the first reactor to bring the first raw material composition to a first temperature in the range of 0 to 850 ° C. A first heat medium is fed to the first reactor so as to be a reaction product.
The temperature of the first heat medium supplied to the first reactor is from the time of contact with the first raw material composition in the first reactor until the temperature is supplied to the third reactor. It is a temperature at which the obtained mixture of the first reaction product and the first heat medium, that is, the first mixture can be maintained at the first temperature. Therefore, the temperature of the first heat medium supplied to the first reactor is not necessarily the same as the first temperature, and is appropriately adjusted according to the temperature of the first raw material composition and the like. .

  The first heat medium is not thermally decomposed at the temperature in the first reactor, but is contacted in the step (c), and the temperature of the mixture obtained in the step (b), specifically described below. 2 or when the reaction in the step (c) is carried out at a temperature higher than the first temperature and the second temperature, it is a medium in which no thermal decomposition occurs, specifically 200 to A medium that does not thermally decompose at a temperature of 1300 ° C. is preferred. Examples of the first heat medium include one or more gases selected from water vapor, nitrogen, and carbon dioxide, and use of a gas that contains 50% by volume or more of water vapor, with the balance being nitrogen and / or carbon dioxide. Is preferred. In order to remove HCl generated in the reaction of the step (a) as hydrochloric acid, the content ratio of water vapor in the first heat medium is preferably 50% by volume or more, and a gas substantially consisting of only water vapor (100% by volume). Is particularly preferred.

  The supply amount of the first heat medium to the first reactor is preferably 20 to 98% by volume, and 50 to 95% by volume with respect to the total supply amount of the heat medium and the first raw material composition. Is more preferable. The ratio of the supply amount of the first heat medium to the total supply amount of the first heat medium and the first raw material composition is 20% by volume or more, thereby suppressing the generation of high boilers and carbonization of the raw material. The reaction in the step (a) can be progressed. That is, the reaction for producing trifluoromethylfluorocarbene from R22 via difluorocarbene and TFE can be carried out efficiently and stably. In addition, in the reaction of step (a), the bond / decomposition reaction between difluorocarbene and TFE, and the fluorine transfer between TFE and trifluoromethylfluorocarbene are reversible reactions that occur mutually, and the equilibrium state is stabilized. Is preferred. By setting the first heat medium to 20% by volume or more, the equilibrium state after the reaction in the step (a) is also stably maintained. And thereby, the reaction in the below-mentioned (c) process can be performed in the state controlled enough, and HFO-1234yf can be manufactured efficiently. Moreover, since productivity will fall remarkably when the said ratio exceeds 98 volume%, it is not industrially realistic.

  Thus, after the 1st heat medium supplied to a 1st reactor and the 1st raw material composition containing R22 contact, in (c) process, the (a) obtained in process (a) The time until the mixture of 1 is supplied to the third reactor (hereinafter referred to as the first residence time) is preferably 0.01 to 10 seconds, preferably 0.1 to 3.0 seconds. More preferably. By setting the first residence time to 0.01 to 10 seconds, the reaction in the step (a) can be sufficiently advanced. The first residence time can be controlled by adjusting the supply amount (flow rate) of the first raw material composition to the first reactor.

(First reactor)
The shape of the first reactor is not particularly limited as long as it can withstand the temperature and pressure in the following first reactor, and examples thereof include a cylindrical vertical reactor. Examples of the material of the first reactor include glass, iron, nickel, or an alloy mainly composed of iron and nickel.

  The temperature in the first reactor in the step (a) is such that the first raw material composition is a first temperature in the range of 0 to 850 ° C., and the resulting first mixture is the It is assumed that the temperature is maintained at the first temperature (hereinafter referred to as the first internal temperature). Such a first internal temperature is also the first temperature. That is, by setting the temperature in the first reactor to the first temperature in the range of 0 to 850 ° C., the first raw material composition becomes the first temperature in the range of 0 to 850 ° C. The first reaction product can be obtained.

  The temperature in the first reactor can be controlled by adjusting the temperature and pressure of the first heat medium supplied to the first reactor. The interior of the first reactor can also be supplementarily heated with an electric heater or the like so that the temperature in the first reactor becomes the temperature in the first reactor. The first internal temperature is preferably in the range of 500 to 850 ° C, more preferably in the range of 500 to 800 ° C, and particularly preferably in the range of 400 to 750 ° C.

  By setting the temperature in the first reactor to the first temperature in the first reactor, TFE produced from R22 via difluorocarbene can be produced in a sufficiently high yield in the reaction in the step (a). Furthermore, in the three-state equilibrium state of difluorocarbene, TFE and trifluoromethylfluorocarbene in the obtained first mixture, it is possible to maintain a high ratio of trifluoromethylfluorocarbene. Thus, if the proportion of trifluoromethylfluorocarbene in the first mixture obtained in the reaction of step (a) can be increased, HFO-1234yf is more efficient than VdF in step (c). Can be manufactured.

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

<(B) Process>
In step (b) of the present invention, the second raw material composition containing R40 and / or R50 is supplied to the second reactor, and the second heat medium is supplied to the second reactor. . Then, the second heat medium is brought into contact with the second raw material composition in the second reactor to bring the second raw material composition to the second temperature in the range of 600 to 900 ° C. In the step (b), the reaction surrounded by the frame (B) in the above formula (1) is performed separately in the second reactor. Hereinafter, the reaction surrounded by the frame (B) is referred to as the reaction in the step (b) as necessary.
The second temperature is preferably in the range of 700 to 900 ° C, and more preferably in the range of 760 to 900 ° C. In addition, it is preferable that this 2nd temperature is higher than 1st temperature which is the temperature of the 1st raw material composition in the said (a) process.

  The second raw material composition containing R40 and / or R50 is heated and maintained at a second temperature in the range of 600 to 900 ° C. by contact with the second heat medium in the second reactor. And the 2nd reaction product containing R40 and / or R50 which is a methyl radical (intermediate active species 3) produced | generated by thermal decomposition of R40 and / or R50, a dechlorination reaction, or a dehydrogenation reaction, and an unreacted raw material Is considered to generate. In addition, the mixture of the second reaction product and the second heat medium becomes the second mixture obtained in the step (b).

(Second raw material composition)
The second raw material composition used in the step (b) includes at least one of R40 and R50, and has each aspect of using R40 alone, using R50 alone, or using a mixture of R40 and R50.

  In addition, the molar ratio of the amount of R40 and / or R50 supplied to the second reactor in step (b) and the amount of R22 supplied to the first reactor in step (a) (hereinafter referred to as (R40 + R50). ) / R22) is preferably in the range of 0.01-5. The range of 0.1-3 is more preferable, and the range of 0.1-1.5 is particularly preferable. By setting (R40 + R50) / R22 to 0.01 to 5, the conversion rate of R40 and / or R50 can be increased, and HFO-1234yf can be produced efficiently.

  The temperature of R40 and / or R50 supplied to the second reactor is preferably 0 to 1200 ° C. from the viewpoint of reactivity. From the standpoint of further increasing the reactivity, it is preferable to preheat (preheat) R40 and / or R50 to normal temperature (25 ° C.) or higher and 1200 ° C. or lower before introducing the second reactor into the second reactor. More preferably, it is preheated. However, the temperature of each component supplied to the second reactor is set to be equal to or lower than the second temperature. Moreover, when using both R40 and R50, the supply to these 2nd reactors may be separate, and may be supplied after mixing.

(Second heat medium)
In the step (b), the second raw material composition is brought into contact with the second raw material composition in the second reactor to bring the second raw material composition to a second temperature in the range of 600 to 900 ° C. A second heat medium is fed to the second reactor so as to be a reaction product.
The temperature of the second heat medium supplied to the second reactor is obtained during the period from the contact with the second raw material composition in the second reactor to the supply to the third reactor. The temperature of the mixture of the second reaction product and the second heat medium, that is, the temperature at which the second mixture can be maintained at the second temperature. Therefore, the temperature of the second heat medium supplied to the second reactor is not necessarily the same as the second temperature, and is appropriately adjusted according to the temperature of the second raw material composition and the like. .

  The second heat medium is not thermally decomposed at the second temperature, but is contacted in the step (c). The temperature of the first mixture obtained in the step (a), specifically as described above. When the first temperature or the temperature at which the reaction is carried out in the step (c) is higher than the first temperature and the second temperature, it is a medium that does not undergo thermal decomposition at the temperature. The medium is preferably a medium that does not thermally decompose at a temperature of 200 to 1300 ° C. Examples of the second heat medium include the same gas as the first heat medium. The use of a gas consisting essentially only of water vapor (100% by volume) is particularly preferred. Moreover, it is preferable that the first heat medium and the second heat medium are the same kind of gases that differ only in the supply temperature.

  The supply amount of the second heat medium to the second reactor is preferably 20 to 98% by volume, and preferably 50 to 95% by volume, with respect to the total supply amount of the heat medium and the second raw material composition. Is more preferable. By making the ratio of the supply amount of the second heat medium with respect to the total supply amount of the second heat medium and the second raw material composition 20% by volume or more, generation of high boilers and carbonization of the raw material can be achieved. While suppressing, the reaction of the said (b) process can be advanced and a methyl radical can be produced | generated stably. And thereby, the reaction in the below-mentioned (c) process can be performed in the state controlled enough, and HFO-1234yf can be manufactured efficiently. Moreover, since productivity will fall remarkably when the said ratio exceeds 98 volume%, it is not industrially realistic.

  Thus, after the 2nd heat carrier supplied to the 2nd reactor and the 2nd raw material composition containing R40 and / or R50 contact, in (c) process, in (b) process The time until the obtained second mixture is supplied to the third reactor (hereinafter referred to as the second residence time) is preferably 0.001 to 10 seconds, 0.05 to 3 More preferably, it is 0 seconds. By setting the second residence time to be 0.001 to 10 seconds, the methyl radical production reaction can be sufficiently advanced. The second residence time can be controlled by adjusting the supply amount (flow rate) of the second raw material composition to the second reactor.

(Second reactor)
The shape of the second reactor is not particularly limited as long as it can withstand the temperature and pressure in the following second reactor, and examples thereof include a cylindrical vertical reactor. Examples of the material for the second reactor include glass, iron, nickel, and alloys containing iron and nickel as main components.

  The temperature in the second reactor in the step (b) is such that the second raw material composition is set to a second temperature in the range of 600 to 900 ° C., and the resulting second mixture is The temperature is maintained at the second temperature (hereinafter referred to as the second internal temperature). Such a second internal temperature is also the second temperature. That is, by setting the temperature in the second reactor to a second temperature in the range of 600 to 900 ° C., the second raw material composition becomes the second temperature in the range of 600 to 900 ° C. The second reaction product can be obtained.

  The temperature in the second reactor can be controlled by adjusting the temperature and pressure of the second heat medium supplied to the second reactor. The inside of the second reactor can be supplementarily heated by an electric heater or the like so that the temperature in the second reactor becomes the second inside temperature. The second internal temperature is preferably in the range of 700 to 900 ° C, more preferably in the range of 760 to 900 ° C.

  By setting the temperature in the second reactor to the temperature in the second reactor, in the reaction of step (b) in the reaction system represented by the above formula (1), dechlorination reaction or dehydrogenation reaction is performed. The reaction rate is increased and methyl radicals can be obtained in a sufficiently high yield.

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

<(C) Process>
In the step (c) of the present invention, the first mixture obtained in the step (a) and the second mixture obtained in the step (b) are supplied to a third reactor. And brought into contact in the third reactor to a third temperature. By the step (c), the reaction within the frame (C) showing the whole formula (1) is performed. That is, by this step (c), the difluorocarbene and trifluoromethylfluorocarbene in the frame (A) react with the methyl radical in the frame (B) as shown by the route B and the route A, respectively. , VdF and HFO-1234yf.

Here, the first mixture obtained in step (a) is a compound within the frame (A) in formula (1) and an intermediate active species, that is, R22, TFE, difluorocarbene, trifluoromethylfluorocarbene, and It is a mixture that includes the first heat medium and is adjusted to the first temperature so as to be in an equilibrium state with a high proportion of trifluoromethylfluorocarbene as described above. In addition, when the 1st raw material composition contains the fluorine-containing compound used as carbene sources other than TFE, the 1st mixture contains this fluorine-containing compound itself and its thermal decomposition product in addition to the above. However, it is adjusted so as to be balanced in the state where the abundance ratio of trifluoromethylfluorocarbene is high within the first temperature range as described above.
In addition, the second mixture obtained in the step (b) includes the compound in the frame (B) in the formula (1) and the intermediate active species, that is, R40 and / or R50, methyl radical, and the second heat medium. And a mixture adjusted to the second temperature under conditions where a large amount of methyl radicals are produced.

  In the production method of the present invention, the mixture thus adjusted to the optimum temperature condition is brought into contact with each other in the third reactor in the step (c), so that the inside of the frame (C) Compared with the reaction by the route B, the reaction by the route A is preferentially caused to generate HFO-1234yf efficiently. Note that the first mixture obtained in the step (a) and the second mixture obtained in the step (b) are all present in the respective reactors and supplied to the third reactor as they are. Is done.

  The third temperature in step (c) is the first mixture held at the first temperature supplied to the third reactor and the second temperature held at the second temperature, unless heated. It is controlled by the ratio of the supply amount to the mixture. Here, since the ratio of the supply amount of the first mixture and the second mixture supplied to the third reactor is defined as the above (R40 + R50) / R22, the third temperature is controlled. The degree of freedom to do is small. In order to control the third reactor, for example, a method of supplying a third heat medium to the third reactor or a method of heating with an electric heater or the like may be employed.

  In addition, it is preferable that the 3rd temperature shall be 600-1200 degreeC from a reactive viewpoint, and the range of 600-900 degreeC is further more preferable. By setting the third temperature to 600 to 1200 ° C., the reaction by the route A can be preferentially caused compared to the reaction by the route B in the frame (C), whereby HFO-1234yf / The value of VdF can be increased, that is, the production efficiency of HFO-1234yf can be increased.

In the step (c), the time from when the first mixture and the second mixture are brought into contact with each other to be led out of the third reactor, that is, the supplied first mixture and second mixture are: After contacting in the third reactor, the time of staying in the reactor and being maintained at the third temperature (hereinafter referred to as the third residence time) is 0.01 to 10 seconds. It is preferable to set it to 0.2 to 3.0 seconds. By setting the third residence time to 0.01 to 10 seconds, the reaction by the path A can be preferentially caused as compared with the reaction by the path B, and thereby HFO-1234yf can be generated efficiently.
The third residence time can be controlled by adjusting the supply amount (flow rate) of the first mixture and the second mixture to the third reactor.

(Third reactor)
The shape of the third reactor is not particularly limited as long as it can withstand the third temperature and the following pressure, and examples thereof include a cylindrical vertical reactor. Examples of the material for the third reactor include glass, iron, nickel, and alloys containing iron and nickel as main components.

The method for controlling the temperature in the third reactor is as described above. As a method of controlling the temperature in the third reactor, a method of heating with an electric heater or the like is preferable.
The pressure in the third reactor is preferably 0 to 2 MPa in gauge pressure, and more preferably in the range of 0 to 0.5 MPa.

<Reactor>
In the present invention, an example of a reaction apparatus used for production of HFO-1234yf is shown in FIG.
The reaction apparatus 20 includes a first reactor 1, a second reactor 2, and a third reactor 3 each including heating means such as an electric heater. In addition, installation of the heating means in these reactors is not essential.

  The first reactor 1 is connected to a supply line 4 for the first raw material composition containing R22 and a supply line 5 for water vapor as the first heat medium. A supply line 6 for the second raw material composition containing R40 and / or R50 and a supply line 7 for water vapor as the second heat medium are connected. The first raw material composition supply line 4 and the second raw material composition supply line 6 are provided with preheaters (preheaters) 4a and 6a each equipped with an electric heater or the like. The composition is preheated to a predetermined temperature and then supplied to the first reactor 1 and the second reactor 2. The first steam supply line 5 and the second steam supply line 7 are provided with superheated steam generators 5a and 7a, respectively, and are mixed with the superheated steam so that the first steam and After the temperature and pressure of the second water vapor are adjusted to predetermined values, they are supplied. The superheated steam generators 5a and 7a may be preheaters (preheaters) equipped with an electric heater or the like. Further, it is not essential to install the preheaters (preheaters) 4a and 6a in the first raw material composition supply line 4 and the second raw material composition supply line 6.

  When the first raw material composition contains a fluorine-containing compound that becomes a carbene source in addition to R22, as shown in FIG. 1, the first raw material composition supply line 4 connected to the first reactor 1 is 1 A mixture of R22 and the fluorine-containing compound serving as the carbene source may be supplied to the first reactor 1 via the preheater 4a. However, the R22 supply line and the fluorine-containing compound serving as the carbene source may be used. A compound supply line may be provided separately, and each supply line may be connected to the first reactor 1 via a preheater provided separately.

  When the second raw material composition contains both raw material components of R40 and R50, as shown in FIG. 1, the second raw material composition supply line 6 is one, and the mixture of R40 and R50 is The preheater 6a may be supplied to the second reactor 2, but a R40 supply line and a R50 supply line are separately provided, and each of the supply lines is provided separately. Then, it may be connected to the second reactor 2.

  A first reaction product containing TFE, difluorocarbene, trifluoromethylfluorocarbene and the like produced in the first reactor 1 and an unreacted first raw material composition at the outlet of the first reactor 1 A supply line 8 for the first mixture comprising the product and the first heat medium is connected. In addition, from the second reaction product 2 including the methyl radicals generated in the second reactor 2 and the unreacted second raw material composition and the second heat medium at the outlet of the second reactor 2 A second mixture supply line 9 is connected. The other end of the first mixture supply line 8 and the other end of the second mixture supply line 9 are both connected to the third reactor 3.

  An outlet line 11 provided with a cooling means 10 such as a heat exchanger is connected to the outlet of the third reactor 3. In the outlet line 11, a steam and acidic liquid recovery tank 12, an alkali cleaning device 13 and a dehydration tower 14 are further installed in this order. Then, after dehydration by the dehydration tower 14, each component of the outlet gas is analyzed and quantified by an analyzer such as gas chromatography (GC).

<Outlet gas component>
In the production method of the present invention, HFO-1234yf can be obtained as a component of the outlet gas. As compounds other than HFO-1234yf and unreacted raw material components (first raw material composition containing R22, second raw material composition containing R40 and / or R50) contained in the outlet gas, the first reaction product In addition to TFE contained in the product, ethylene, HFP, CTFE, trifluoroethylene, RC318, VdF, 3,3,3-trifluoropropene (CF ₃ CH═CH ₂ : HFO-1243zf) and the like can be mentioned.

Among the components contained in these outlet gases, ethylene having a methylene group (= CH ₂ ) or a methyl group (—CH ₃ ) is derived from the second raw material composition such as R40 and R50 of the raw material component. TFE, HFP, CTFE, trifluoroethylene, RC318, HFO-1243zf, and the like having a fluoro group (-F), and also HFO-1234yf and VdF are all first components such as R22 of the raw material components. It is a compound derived from the raw material composition. HFO-1234yf and VdF are compounds derived from the first raw material composition and compounds derived from the second raw material composition as shown in the above formula (1). Similarly, HFO-1243zf is a compound derived from both raw material compositions.

  The above components other than HFO-1234yf contained in the outlet gas can be removed to a desired extent by known means such as distillation. The separated R22, TFE, R40 and R50 can be recycled as a part of the raw material composition. HFP, trifluoroethylene, and RC318 are also fluorine-containing compounds that serve as carbene sources, and can be recycled as part of the first raw material composition. In particular, RC318 is suitable as a fluorine-containing compound serving as a carbene source. Since VdF hardly functions as a carbene source under the above reaction conditions, it is preferably separated and recovered.

  VdF, HFP, CTFE, etc. obtained by separation and recovery may be polyvinylidene fluoride, FEP (TFE-HFP copolymer), VdF-HFP copolymer, PCTFE (CTFE polymer), ECTFE, if necessary. It can also be used as a raw material for fluororesins such as (ethylene-CTFE copolymer).

  In the production method of the present invention, at least one of R22 and R40 and R50, which are easy to procure, is used as a raw material, and each raw material component is divided into two groups, and a reaction such as decomposition under optimum temperature conditions for each group. And generating intermediate active species, respectively, and then reacting these intermediate active species without taking them out of the reaction system, so that HFO- useful as a new refrigerant having a low global warming potential (GWP) of 4 1234yf can be manufactured efficiently. Therefore, the production method of the present invention, for example, reduces the cost required for raw materials and production equipment as compared with a method that requires HST-1234yf using HCFC-225ca as a raw material and producing HFO-1234yf via CFO-1214ya. Not only can it be reduced, but the energy required for manufacturing can be greatly reduced.

  In the production method of the present invention, in the steps (a) and (b), a heating medium is used when two groups of raw material components are heated and decomposed under optimum temperature conditions for each group. Therefore, it is easy to control the production (reaction) conditions, particularly the temperature conditions, and there is almost no risk of clogging of the reactor due to the formation of high boilers or carbonization of raw materials. Thereby, in the step (c), the reaction product containing the raw material component and the intermediate active species is supplied together with the heat medium in a stable equilibrium state, and the reaction of the route A takes precedence over the reaction of the route B in the above formula (1). Thus, HFO-1234yf / VdF is increased, and stable and quantitative production of HFO-1234yf becomes possible. Furthermore, it is also possible to recycle the TFE or fluorinated compound that is a carbene source obtained as a by-product and use it as a raw material component, which is particularly economical.

  In particular, in a synthesis reaction involving thermal decomposition using R22 and R40 as raw materials, the proportion of HFO-1234yf in the reaction product is increased relative to VdF, which tends to be high in the reaction product. This is economically advantageous.

  Furthermore, the production method of the present invention is compared with the method of producing HFO-1234yf by supplying R22 and R40 and / or R50 all at once to the reactor and contacting with the heat medium in the reactor for a predetermined time. Thus, there is an advantage that HFO-1234yf / VdF can be increased by increasing the production amount of HFO-1234yf in comparison with the production amount of VdF.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Examples 1 to 4 are examples, and example 5 is a comparative example.

[Example 1]
Using the reaction apparatus shown in FIG. 1, crude HFO-1234yf was obtained from the first source gas consisting of R22 and the second source gas consisting of R40 as follows.

(A) Process R22 was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and R22 as 1st raw material gas was preheated to 300 degreeC.
The preheated R22 and steam (steam) heated by an electric furnace set at a furnace temperature of 750 ° C. have a volume ratio of steam / R22 = 90/10 (steam relative to the supply amount of the whole gas (R22 + steam)) The volume ratio of the supply amount is 90 / (10 + 90) = 0.9 (90%)), and the internal temperature (gauge pressure) is 0.042 MPa and the internal temperature is controlled to 750 ° C. To the reactor (hereinafter referred to as reactor A). Hereinafter, all the pressures are assumed to be gauge pressures.

  The flow rate of the water vapor and R22 (amount of supply per unit time) is controlled so that the residence time of the gas (water vapor and R22) in the reactor A is 0.25 seconds, and the outlet gas (R22, R22, A first mixture comprising difluorocarbene, TFE, trifluoromethylfluorocarbene, water vapor, etc., hereinafter referred to as “first mixture”) is controlled in a third reactor (hereinafter referred to as reactor) whose internal temperature is controlled at 850 ° C. C)). The temperature of the first mixture (first temperature) was 750 ° C.

(B) Process R40 was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and R40 as 2nd raw material gas was heated to 300 degreeC (preheating). The preheated R40 and steam (water vapor) heated by an electric furnace set at a furnace temperature of 800 ° C. are steam / R40 = 90/10 at an internal pressure (gauge pressure) of 0.042 MPa. It was supplied to a second reactor (hereinafter referred to as reactor B) controlled at a temperature of 800 ° C. The flow rate of R40 and water vapor (amount of supply per unit time) is controlled so that the residence time of the gas in the reactor B (water vapor and R40) is 1.65 seconds, and the outlet gas of the reactor B (R40, A second mixture composed of methyl radicals, water vapor, and the like (hereinafter referred to as “second mixture”) was introduced into the reactor C controlled at an internal temperature of 850 ° C. The temperature of the second mixture (second temperature) was 800 ° C.

(C) Process In the reactor C, the 1st mixture supplied from the said reactor A and the 2nd mixture supplied from the said reactor B were made to contact.
Here, the molar ratio of R40 supplied to the reactor B and R22 supplied to the reactor A was R40 / R22 = 83.3 / 16.7 = 5.0.
It should be noted that the water vapor supply amount relative to the total gas supply amount supplied to the reactor C, that is, the total amount of the R22 supply amount to the reactor A and the R40 supply amount to the reactor B, and the reactor A and The total volume ratio of the amount of steam supplied to the reactor B is steam / (R40 + R22) = 90/10. That is, the volume ratio of R40, R22, and water vapor is R40 / R22 / water vapor = 8.3 / 1.7 / 90.

  In this way, the flow rate of the raw material gas and water vapor supplied to the reactor A and the reactor B (supply amount per unit time) is controlled so that the residence time of the mixed gas in the reactor C is 1.0 second, The outlet gas was taken out from the outlet of the reactor C. The actually measured value (third temperature) of the reactor internal temperature was 850 ° C., and the actually measured value of the reactor C internal pressure (gauge pressure) was 0.042 MPa.

  The outlet gas taken out from the outlet of the reactor C includes unreacted source gas in addition to the gas generated or by-produced by the reaction. In the following description, the outlet gas may be referred to as the generated gas. is there.

Next, the outlet gas taken out from the outlet of the reactor C is cooled to 100 ° C. or lower, and after performing steam and acidic liquid recovery and alkali washing in order, dehydration treatment is performed, and gas chromatographic analysis is performed. The molar composition of the gas components contained was calculated. These results are shown in Table 1 together with the reaction conditions.
In addition, the preheat temperature of R40 and R22 is a set temperature in each electric furnace for preheating, 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.

  Further, based on the molar composition of the outlet gas obtained by gas chromatography analysis, the conversion rate of R40 and / or R50 (reaction rate), the conversion rate of R22 (reaction rate), and selection of each component derived from R22 And the molar ratio of HFO-1234yf and VdF (HFO-1234yf / VdF) were determined. These results are shown in the lower column of Table 1.

The above values mean the following respectively.
(R40 and / or R50 conversion (reaction rate))
Of the components derived from R40 and / or R50 in the outlet gas, when the proportion of R40 and / or R50 (R40 and / or R50 yield) is X%, (100-X)% is R40 and / or It is called the conversion rate (reaction rate) of R50. It means the proportion (mol%) of reacted R40 and / or R50.

(R22 conversion rate (reaction rate))
Among the components derived from R22 in the outlet gas, when the proportion of R22 (R22 yield) is X%, (100-X)% is referred to as the conversion rate (reaction rate) of R22. It means the ratio (mol%) of reacted R22.
(Yield of each component derived from R22)
Ratio (mol%) of each compound other than R22 in R22-derived components in the 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”.

(HFO-1234yf / VdF)
It is a ratio (molar ratio) of HFO-1234yf to VdF in the outlet gas.
It is determined by “mol% of HFO-1234yf in the outlet gas” / “mol% of VdF in the outlet gas”. This represents the ratio (molar ratio) of HFO-1234yf to VdF in the outlet gas.

[Example 2]
(A) Process R22 was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and R22 as 1st raw material gas was preheated to 300 degreeC.
The internal pressure (gauge pressure) of the preheated R22 and the steam (water vapor) heated by an electric furnace set at a furnace temperature of 500 ° C. is set so that the volume ratio is water vapor / R22 = 90/10. The reactor A was supplied at 0.042 MPa and the internal temperature was controlled at 500 ° C.

  The flow rate of the water vapor and R22 (amount of supply per unit time) is controlled so that the residence time of the gas (water vapor and R22) in the reactor A is 0.25 seconds, and the outlet gas (R22, R22, A first mixture comprising difluorocarbene, TFE, trifluoromethylfluorocarbene, water vapor and the like was introduced into the reactor C controlled at an internal temperature of 800 ° C. The temperature of the first mixture (first temperature) was 500 ° C.

(B) Process R40 was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and R40 as 2nd raw material gas was heated to 300 degreeC (preheating). The preheated R40 and steam (water vapor) heated by an electric furnace set at a furnace temperature of 800 ° C. are steam / R40 = 90/10 at an internal pressure (gauge pressure) of 0.042 MPa. The temperature (second temperature) was supplied to the reactor B controlled at 800 ° C. The flow rate of R40 and water vapor (amount of supply per unit time) is controlled so that the residence time of the gas in the reactor B (water vapor and R40) is 1.65 seconds, and the outlet gas of the reactor B (R40, A second mixture comprising methyl radicals, water vapor and the like was introduced into the reactor C controlled at an internal temperature of 800 ° C. The temperature of the second mixture (second temperature) was 800 ° C.

(C) Process In the reactor C, the 1st mixture supplied from the said reactor A and the 2nd mixture supplied from the said reactor B were made to contact.
Here, the molar ratio of R40 supplied to the reactor B and R22 supplied to the reactor A was R40 / R22 = 33/67 = 0.5.
It should be noted that the water vapor supply amount relative to the total gas supply amount supplied to the reactor C, that is, the total amount of the R22 supply amount to the reactor A and the R40 supply amount to the reactor B, and the reactor A and The total volume ratio of the amount of steam supplied to the reactor B is steam / (R40 + R22) = 90/10. That is, the volume ratio of R40, R22, and water vapor is R40 / R22 / water vapor = 3.3 / 6.7 / 90.

In this way, the flow rate of the raw material gas and water vapor supplied to the reactor A and the reactor B (supply amount per unit time) is controlled so that the residence time of the mixed gas in the reactor C is 1.0 second, The outlet gas was taken out from the outlet of the reactor C. The actually measured value (third temperature) of the reactor internal temperature was 800 ° C., and the actually measured value of the reactor C internal pressure (gauge pressure) was 0.042 MPa.
Next, the outlet 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.

[Example 3]
The reaction was carried out under the same conditions as in Example 2 except that the internal temperature in the reactor C was controlled at 750 ° C. and the measured value (third temperature) in the reactor was changed to 750 ° C. After the same treatment, the outlet gas taken out from the outlet of the reactor C was similarly analyzed. The results are shown in Table 1 together with the reaction conditions.

[Example 4]
The reaction was carried out under the same conditions as in Example 3 except that R50 was used instead of R40. Next, the outlet gas taken out from the outlet of the reactor C was treated in the same manner as in Example 1 and then analyzed in the same manner. The results are shown in the lower column of Table 1.

[Example 5]
Using the reaction apparatus shown in FIG. 2, crude HFO-1234yf was obtained from a raw material composition (raw material gas) composed of R22 and R40 as follows.

  Here, the reaction apparatus 30 shown in FIG. 2 has the batch reactor 21 provided with heating means, such as an electric heater. The batch reactor 21 is connected to a supply line 22 for R40, a supply line 23 for R22, and a supply line 24 for water vapor as a heat medium.

  The R40 supply line 22 and the R22 supply line 23 are provided with preheaters (preheaters) 22a and 23a each equipped with an electric heater or the like, and after each raw material component to be supplied is preheated to a predetermined temperature. A batch reactor 21 is supplied. The steam supply line 24 is provided with a preheater (preheater) 24a equipped with an electric heater or the like, and is supplied with steam whose temperature and pressure are adjusted. By connecting the supply lines 22, 23, 24 after passing through the respective preheaters 22 a, 23 a and the superheated steam generator 24 a, all the components are mixed and reacted together from the raw material / steam mixed supply line 25. Is supplied to the vessel 21.

  And the exit line 11 in which the cooling means 10 like a heat exchanger was installed is connected to the exit of the batch reactor 21. In the outlet line 11, a steam and acidic liquid recovery tank 12, an alkali cleaning device 13 and a dehydration tower 14 are further installed in this order. Then, after dehydration by the dehydration tower 14, each component of the outlet gas is analyzed and quantified by an analyzer such as gas chromatography (GC).

  R40 was continuously introduced into a stainless steel tube in an electric furnace set to a furnace temperature of 500 ° C., which was the R40 preheater 22a, and R40 was heated to 500 ° C. (preheating). Further, R22 was continuously introduced into a stainless steel tube in an electric furnace set to a furnace temperature of 500 ° C., which is the R22 preheater 23a, and R22 was preheated to 500 ° C.

  These preheated raw material gas components (R40, R22) and steam (water vapor) heated by an electric furnace set at a furnace temperature of 850 ° C., which is the preheater 24a for steam, are supplied in moles of supply amount of raw material components. The ratio is R40 / R22 = 83.3 / 16.7 = 5.0, and the volume ratio of the supply amount of water vapor to the whole raw material composition is water vapor / (R40 + R22) = 90/10 (that is, R40 / R22 / water vapor = 8.3 / 1.7 / 90), and was supplied to the batch reactor 21 controlled at an internal temperature (gauge pressure) of 0.042 MPa and an internal temperature of 850 ° C.

  In this way, the flow rate of the raw material gas (supply amount per unit time) was controlled so that the residence time of the mixed gas in the batch reactor 21 was 1.0 second, and the product gas was taken out from the outlet of the reactor. The actually measured value of the temperature in the batch reactor 21 was 850 ° C., and the actually measured value of the pressure in the reactor (gauge pressure) was 0.042 MPa.

  Next, the outlet gas taken out from the outlet of the batch reactor 21 is cooled to 100 ° C. or lower, and after performing steam and acidic liquid recovery and alkali washing in order, dehydration treatment is performed, and then the gas is analyzed by gas chromatography. Based on the molar composition of the outlet gas obtained, R40 and / or R50 conversion (reaction rate), R22 conversion (reaction rate), derived from R22 The selectivity of each component and the molar ratio of HFO-1234yf and VdF (HFO-1234yf / VdF) were determined in the same manner as in Example 1. The results are shown in Table 1 together with the reaction conditions.

  As can be seen from Table 1, in Examples 1 to 4, R22 and R40, or R22 and R50 are used as raw materials, and each raw material component is R22, which is a compound containing a fluorine atom, and R40, which is a compound containing no fluorine atom. By dividing into two groups, R50, and generating the desired intermediate active species under optimum temperature conditions for each group, and then bringing these intermediate active species into contact with each other without removing them from the reaction system. HFO-1234yf could be produced more efficiently than in Example 5, which was batch-mixed from the beginning.

  According to the production method of the present invention, R22 and R40 and / or R50 which are easy to procure are used as raw materials, and these raw materials are divided into two groups of a compound containing a fluorine atom and a compound not containing a fluorine atom, After generating the desired intermediate active species under optimum temperature conditions for each group of these groups, the intermediate active species are brought into contact with each other without being removed from the reaction system, whereby industrially useful HFO-1234yf is obtained. It can be efficiently manufactured in a sufficiently controlled state. Therefore, compared with a conventionally known method for producing HFO-1234yf, the cost required for raw materials and production equipment can be greatly reduced.

  Further, according to the production method of the present invention, the reaction can be carried out in the presence of a heat medium, so that the formation of high-boiling substances can be greatly suppressed, and the production (reaction) conditions can be easily controlled. HFO-1234yf can be manufactured with great economic merit. Specifically, in a synthesis reaction involving thermal decomposition using R22 and R40 and / or R50 as a raw material, the proportion of HFO-1234yf in the reaction product tends to be high in the reaction product. It is economically advantageous in that the relative relationship with VdF can be a certain value or more. Furthermore, it is possible to recycle by-products, which has a great economic effect.

DESCRIPTION OF SYMBOLS 1 ... 1st reactor (reactor A), 2 ... 2nd reactor (reactor B), 3 ... 3rd reactor (reactor C), 4 ... Supply line of 1st raw material composition DESCRIPTION OF SYMBOLS 5 ... Supply line of 1st steam, 6 ... Supply line of 2nd raw material composition, 7 ... Supply line of 2nd steam, 4a, 6a ... Preheater (preheater), 5a, 7a ... Superheated steam generation 8 ... First mixture supply line, 9 ... Second mixture supply line, 10 ... Cooling means, 11 ... Outlet line, 12 ... Steam and acidic liquid recovery tank, 13 ... Alkaline cleaning device, 14 ... Dehydration Tower, 20 ... reactor.

Claims (18)

Using a first raw material composition containing chlorodifluoromethane and a second raw material composition containing chloromethane and / or methane, 2,3,3,3-tetrafluoropropene is produced by a synthesis reaction involving thermal decomposition. A method of manufacturing comprising:
(A) Supplying and contacting the first raw material composition and the first heat medium in a first reactor, and bringing the first raw material composition into a first temperature in the range of 0 to 850 ° C. Obtaining a first mixture; and
(B) supplying and contacting the second raw material composition and the second heat medium into the second reactor, and bringing the second raw material composition into a second temperature in the range of 600 to 900 ° C. Obtaining a second mixture, and
(C) Supplying and bringing the first mixture obtained in the step (a) and the second mixture obtained in the step (b) into contact with each other in the third reactor. A process for producing 2,3,3,3-tetrafluoropropene.   The method for producing 2,3,3,3-tetrafluoropropene according to claim 1, wherein the first temperature is 400 to 750C.   The method for producing 2,3,3,3-tetrafluoropropene according to claim 1 or 2, wherein the second temperature is 760 to 900 ° C.   The total amount of the chloromethane and / or the methane supplied to the second reactor in the step (b) is the amount of the chlorodifluoromethane supplied to the first reactor in the step (a). The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 3, wherein the amount is 0.01 to 5 mol per 1 mol of.   The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 4, wherein the temperature of the chlorodifluoromethane supplied to the first reactor is 0 to 600C. .   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 5, wherein a temperature of the chloromethane and / or methane supplied to the second reactor is 0 to 1200 ° C. Manufacturing method.   The said (c) process WHEREIN: A said 1st mixture and a said 2nd mixture are made to contact and these are made into the 3rd temperature of the range of 600-1200 degreeC, The any one of Claims 1-6. A process for producing 2,3,3,3-tetrafluoropropene according to claim 1.   The said 1st heat medium and the said 2nd heat medium are media which are not thermally decomposed at 200-1300 degreeC, respectively, 2,3,3,3- of Claim 1-7. A method for producing tetrafluoropropene.   The first heat medium and the second heat medium are both one kind or two or more kinds of gases selected from water vapor, nitrogen, and carbon dioxide. A method for producing 2,3,3,3-tetrafluoropropene.   In the step (a), the supply amount of the first heat medium to the first reactor is 20 to 98 volumes with respect to the total supply amount of the heat medium and the first raw material composition. %, The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 9.   In the step (b), the supply amount of the second heat medium to the second reactor is 20 to 98 volumes with respect to the total supply amount of the heat medium and the second raw material composition. %, The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 10.   From the contact of the first raw material composition and the first heat medium in the step (a) to the supply of the first mixture to the third reactor in the step (c). The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 11, wherein the time is 0.01 to 10 seconds.   Until the second mixture is supplied to the third reactor in the step (c) after the second raw material composition and the second heat medium are contacted in the step (b). The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 12, wherein the time is 0.001 to 10 seconds.   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 13, wherein in the step (a), the pressure in the first reactor is 0 to 2 MPa in gauge pressure. Manufacturing method.   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 14, wherein in the step (b), the pressure in the second reactor is 0 to 2 MPa as a gauge pressure. Manufacturing method.   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 15, wherein in the step (c), the pressure in the third reactor is 0 to 2 MPa as a gauge pressure. Manufacturing method.   In the step (a), together with the chlorodifluoromethane, one or more fluorine-containing compounds selected from tetrafluoroethylene, trifluoroethylene, hexafluoropropene, and octafluorocyclobutane are supplied to the first reactor. The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 16.   18. The time of staying in the third reactor after contacting the first mixture and the second mixture in the step (c) is 0.01 to 10 seconds. A method for producing 2,3,3,3-tetrafluoropropene according to any one of the above.

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