JP2014129259A - Method for producing 2,3,3,3-tetrafluoropropene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economically advantageous method for producing HFO-1234yf useful as a new cooling medium with a sufficiently high yield by a reaction involving thermal decomposition.SOLUTION: There is provided a method for producing HFO-1234yf by a reaction involving thermal decomposition using a first raw material composition containing R22 and TFE and a second raw material composition containing R40 and/or R50, the method comprising the steps of: (a) feeding the first raw material composition and a first heating medium into a first reactor to be brought into contact with each other and setting the first raw material composition at 0 to 850°C to obtain a first mixture; (b) feeding the second raw material composition and a second heating medium into a second reactor to be brought into contact with each other and setting the second raw material composition at 600 to 900°C to obtain a second mixture; and (c) feeding the first mixture obtained in the (a) step and the second mixture obtained in the step (b) into a third reactor to be brought into contact with each other.

Description

  The present invention relates to a method for producing 2,3,3,3-tetrafluoropropene, and in particular, 2,3,3 from a raw material composition containing chlorodifluoromethane, tetrafluoroethylene, chloromethane and / or methane. , 3-tetrafluoropropene.

  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.

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-difluoroethylene A method for producing (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 method described in Patent Document 1, since reaction conditions and the like are set using VdF as a target substance, VdF can be obtained in a high yield, but it is not a method for efficiently producing HFO-1234yf.

  Moreover, in the method shown in Patent Document 2, there is a possibility that high boiling substances are generated and carbonization of the raw material occurs with an increase in residence time, and the reactor may be clogged. Therefore, a special anti-corrosion device (for example, a reaction tube lined with platinum) is necessary, and it was not a realistic method when considering industrial production.

  Further, in both methods disclosed in Patent Document 1 and Patent Document 2, although HFO-1234yf is produced by one reaction, it is difficult to separate by distillation from HFO-1234yf such as chlorotrifluoroethylene (CTFE). The amount of by-products produced increased, and high purity HFO-1234yf could not be obtained in a sufficiently high yield.

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 economically advantageous for producing HFO-1234yf useful as a new refrigerant in a sufficiently high yield by a reaction involving thermal decomposition, using raw materials that are easily procured. It aims to provide a simple method. It is another object of the present invention to provide a method for obtaining high-purity HFO-1234yf without complicated purification operations by suppressing the production of CTFE, which is a by-product that is difficult to be separated from HFO-1234yf by distillation.

The present invention uses a first raw material composition containing chlorodifluoromethane (R22) and tetrafluoroethylene (TFE), and a second raw material composition containing chloromethane (R40) and / or methane (R50). , A method for producing 2,3,3,3-tetrafluoropropene (HFO-1234yf) by a synthetic reaction involving thermal decomposition,
(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, , Refers to 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, at least one of R22 and TFE, and R40 and R50, which are easy to procure, is used as a raw material, and these raw materials are divided into two groups: a compound containing a fluorine atom and a compound containing no fluorine atom. After the desired intermediate active species are generated under optimum temperature conditions for each group, these intermediate active species are brought into contact with each other without being removed from the reaction system, and thus are industrially useful. HFO-1234yf can be produced in a sufficiently high yield. 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, generation of by-products that are difficult to be separated from HFO-1234yf, such as CTFE, is suppressed, so that high-purity HFO-1234yf can be obtained.

  Furthermore, by causing the reaction to occur in the presence of a heat medium, the production of high-boiling substances can be greatly suppressed, and the production (reaction) conditions can be easily controlled, so that quantitative HFO-1234yf can be produced. The economic merit is great. Specifically, in a synthesis reaction involving thermal decomposition using R22, TFE, and R40 and / or R50 as a raw material, the proportion of HFO-1234yf in the reaction product is increased in the reaction product. It is economically advantageous in that it can be a certain value or more in the relative relationship with VdF. 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 TFE and a second raw material composition containing R40 and / or R50. To do. And this manufacturing method, as detailed below,
(A) 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 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 in the second reactor, the second raw material composition is brought to a second temperature in the range of 600 to 900 ° C. Obtaining a second mixture,
(C) having the step of supplying the first mixture obtained in the step (a) and the second mixture obtained in the step (b) to be brought into contact with each other in the third reactor. .

  Hereinafter, with reference to the following formula (1), HFO-1234yf is synthesized by a synthesis reaction involving thermal decomposition, using R22, TFE, R40 and / or R50 as raw materials, which are targets of the production method of the present invention. The reaction system will be described.

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

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

  Then, trifluoromethylfluorocarbene (intermediate active species 2) and difluorocarbene (intermediate active species 1) generated from R22 and TFE and a methyl radical (intermediate active species 3) generated from R40 and / or R50 are bonded to each other. Thus, it is considered that intermediate active species 4 and intermediate active species 5 are generated, and these intermediate active species (intermediate active species 4 and intermediate active species 5) undergo a dehydrogenative radical reaction to generate HFO-1234yf and VdF. . In the 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 compete with each other, and by proceeding with the path A preferentially, in the reaction system represented by the formula (1), HFO-1234yf Can be produced efficiently.

  Usually, such a thermal decomposition reaction is performed by supplying the raw materials, that is, R22 and TFE, and R40 and / or R50 to one reactor, and the above-described reactions proceed almost simultaneously. Therefore, there is a limit in changing the reaction conditions in the reaction system represented by the formula (1) so that the route A is preferentially performed over the route B. In particular, regarding the temperature condition, if the whole raw material components are supplied to one reactor, it is difficult to set the temperature of each reaction to an optimum temperature.

  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 similarly the frame B In step (b) using the second heat medium in the second reactor, and in step (c), the reaction is obtained in the first reactor in step (a). All the components (including the first heat medium) are supplied as a first mixture into the third reactor, and all the components (the first components obtained in the second reactor in step (b)) are supplied. 2) is supplied as a second mixture into the third reactor, and the reaction in the frame C showing the entire formula (1) is performed in the third reactor. It was. Then, by setting the temperature condition in the steps (a) and (b) to the optimum temperature for the reaction in each step, that is, the temperature range shown above, in the step (c), the HFO-1234yf of the route A The generation can be performed with priority over the generation of VdF by the path B.

  The production method of the present invention may be a continuous production method or a batch production method. In the continuous production method, the first raw material composition containing R22 and TFE in step (a) is supplied to the first reactor, and the first heat medium is supplied to the first reactor. The first raw material composition is simultaneously and continuously performed under conditions that allow the temperature of the first raw material composition to fall within the range of the first temperature. 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 by contacting. 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 the first or the same.

  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 step (a) of the present invention, the first raw material composition containing R22 and TFE 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 0 to 800 ° C, more preferably in the range of 0 to 750 ° C, and particularly preferably in the range of 100 to 750 ° C.

  The first raw material composition containing R22 and TFE is heated and maintained at the first temperature within the above range in contact with the first heat medium in the first reactor. And difluorocarbene (intermediate active species 1) and trifluoromethyl fluorocarbene (intermediate active species 2) produced by thermal decomposition, dehydrochlorination reaction and fluorine transfer, unreacted raw material R22, and unreacted raw material. It is considered that a first reaction product containing TFE, which is also a compound produced by thermal decomposition of R22 and dehydrochlorination reaction, is produced. 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 in 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 formula (1) proceeds in preference to the reaction of the route B, and HFO-1234yf can be efficiently produced. 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)
(A) The 1st raw material composition used for a process contains R22 and TFE. In addition to R22 and TFE, the first raw material composition is decomposed by contact with the first heat medium in the first reactor to produce difluorocarbene (intermediate active species 1) or trifluoromethylfluorocarbene (intermediate activity). The compound which can generate | occur | produce seed 2), for example, hexafluoropropene (henceforth HFP), trifluoroethylene, octafluorocyclobutane (henceforth RC318), hexafluoropropene oxide, etc. can be contained.

  From such a fluorine-containing compound that is contained in the first raw material composition and can generate difluorocarbene or the like by thermal decomposition, trifluoromethylfluorocarbene (intermediate) via TFE in the reaction of step (a). Active species 2) are produced. Some of the fluorine-containing compounds directly generate trifluoromethylfluorocarbene by thermal decomposition. If the thermal decomposition reaction occurs in step (a), trifluoromethylfluorocarbene is generated. The obtained trifluoromethylfluorocarbene reacts with the methyl radical (intermediate active species 3) 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. Further, such a fluorine-containing compound as a carbene source may be newly prepared, but from a fluorine-containing compound by-produced by a thermal decomposition reaction in the production method of the present invention, such as HFP, RC318, trifluoroethylene, etc. It is preferable from the viewpoint of recycling to use one or more selected. Among these, RC318 is particularly preferable. Further, the TFE contained in the first mixture can be recovered together with R22 after the completion of the step (c) and used in the first raw material composition, which is particularly preferable from the viewpoint of recycling.

  Here, in addition to R22 and TFE as the first raw material composition, when a fluorine-containing compound that is another carbene source recycled as described above is used, R22 in the first raw material composition is used. The content ratio of TFE and other fluorine-containing compounds as carbene sources is not particularly limited. In addition, the content ratio of difluorocarbene and trifluoromethylfluorocarbene in the first mixture obtained in the step (a) is not limited to the type of the fluorine-containing compound to be used. It is thought to be controlled by temperature.

  The molar ratio (hereinafter referred to as TFE / R22) of the TFE supply amount and the R22 supply amount in the step (a) is preferably in the range of 0.01 to 100, and preferably in the range of 0.1 to 10. Is more preferable. In the present embodiment in which the first raw material composition containing R22 and TFE and the first heat medium are allowed to react by continuously flowing through the first reactor, each of the raw material components and the heat medium The supply amount 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).

  By setting TFE / R22 to 0.01 or more, the first residence time described later can be shortened, and the production of difluorocarbene can be suppressed and the production of trifluoromethylfluorocarbene can be increased. And by suppressing the production | generation of difluorocarbene in this way and raising the production | generation of trifluoromethyl fluoro carbene, by the process (c) mentioned later, the production | generation of by-products, such as VdF and CTFE, is suppressed, and high purity HFO- 1234yf can be obtained. Moreover, HFO-1234yf can be obtained with a higher yield by making TFE / R22 into 100 or less. TFE / R22 is particularly preferably in the range of 0.1 to 3.

Among the first raw material compositions to be supplied to the first reactor, the temperature of R22 and the fluorine-containing compound serving as the carbene source is set to a temperature at which the reactivity is high to some extent but is not easily carbonized. It is preferable to set it as 0-600 degreeC. From the viewpoint of increasing the reactivity, it is preferable that R22 and the fluorine-containing compound serving as a carbene source are preheated (preheated) to room temperature (25 ° C.) or higher and 600 ° C. or lower before being introduced into the first reactor. It is more preferable to preheat (preheat) to 100 to 500 ° C.
Moreover, it is preferable that the temperature of TFE supplied to a 1st reactor shall be 0-600 degreeC from a reactive viewpoint. From the viewpoint of enhancing the reactivity, TFE is preferably preheated (preheated) to room temperature (25 ° C.) or more and 600 ° C. or less before being introduced into the first reactor, and preheated to 100 to 500 ° C. ( It is more preferable to preheat).
However, the temperature of each of the components supplied to the first reactor is set to be equal to or lower than the first temperature.

  The supply of R22, TFE, and the fluorine-containing compound used as the carbene source as needed to the first reactor may be separate, or may be 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 is preferably set to the same temperature as described above.

(First heat medium)
In the step (a), the first heat medium supplied to the first reactor comes into contact with the first raw material composition in the reactor, and the first raw material composition is heated to 0 to 850 ° C. The first reaction product can be obtained by setting the first temperature in the range.
The temperature of the first heat medium supplied to the first reactor is the first reaction product obtained from the time of contact with the first raw material composition until it is supplied to the third reactor. It is the temperature which can hold | maintain the 1st mixture which is a mixture of a 1st and a 1st heat medium to 1st 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 first temperature, and is contacted in the step (c). The temperature of the second mixture obtained in the step (b), specifically described below. When the second 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 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 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 first raw material composition. By setting the ratio of the supply amount of the first heat medium to 20% by volume or more, the reaction in the step (a) can be advanced while suppressing the formation of high boilers and carbonization of the raw material. That is, the reaction for producing trifluoromethylfluorocarbene from R22 via difluorocarbene and TFE can be carried out efficiently and stably. In the reaction of step (a), the bond / decomposition reaction between difluorocarbene and TFE, and the fluorine transfer between TFE and trifluoromethylfluorocarbene are both reversible reactions, and it is preferable that the equilibrium state is stabilized. . By setting the first heat medium to 20% by volume or more, a more uniform mixed gas is obtained, and the equilibrium state after the reaction in the step (a) is also stably maintained. Therefore, the reaction in the step (c) described later is performed. HFO-1234yf can be produced with a high yield. Moreover, since the productivity will fall remarkably when the ratio of the supply amount of a 1st heat medium exceeds 98 volume%, it is not industrially realistic.

  Thus, after the 1st heat carrier supplied to the 1st reactor and the 1st above-mentioned raw material composition contact, in the (c) process, the 1st obtained in the (a) process The time until the mixture is supplied to the third reactor (hereinafter referred to as the first residence time) is preferably 0.01 to 10 seconds, and preferably 0.1 to 3.0 seconds. Is more preferable. By setting the first residence time to 0.01 to 10 seconds, the formation reaction of trifluoromethylfluorocarbene 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 reactor, which will be described later, 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 a temperature at which the first mixture can be maintained at a first temperature in the range of 0 to 850 ° C. (hereinafter referred to as the first temperature in the reactor). ). 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 is set to the first temperature in the range of 0 to 850 ° C. A 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 inside of the first reactor can be supplementarily heated with an electric heater or the like so that the temperature in the first reactor becomes the first inside temperature. The first internal temperature is preferably in the range of 0 to 800 ° C, more preferably in the range of 0 to 750 ° C, and particularly preferably in the range of 100 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 of the step (a). Then, 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. In this way, since the proportion of trifluoromethylfluorocarbene present in the first mixture obtained in the reaction of the step (a) can be increased, in the next step (c), high yield of HFO-1234yf is obtained as compared with VdF. Can be generated at a rate.

  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 at least one of R40 and R50 is supplied to the second reactor, and the second heat medium is supplied to the second reactor. To do. 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 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.

  The molar ratio of the supply amount of R40 and / or R50 in the step (b) and the total supply amount of R22 and TFE in the step (a) (hereinafter referred to as (R40 + R50) / (R22 + TFE)) is 0. The range of .01 to 100 is preferred. The range of 0.1-10 is more preferable, and the range of 0.1-3 is particularly preferable. By setting R40 / (R22 + TFE) to 0.01 to 100, the conversion rate of R40 and / or R50 can be increased, and HFO-1234yf can be produced in a high yield.

  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 of the components 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 heat medium supplied to the second reactor comes into contact with the second raw material composition in the reactor, and the second raw material composition is heated to 600 to 900 ° C. By setting the second temperature within the range, the second reaction product is obtained.
The temperature of the second heat medium supplied to the second reactor is the second reaction product obtained from the time of contact with the second raw material composition until the temperature is supplied to the third reactor. It is the temperature which can hold | maintain the 2nd mixture which is a mixture of a 2nd heat medium and 2nd 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), and 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 controlling the ratio of the supply amount of the second heat medium to 20% by volume or more, the reaction in the step (b) is progressed while suppressing the formation of high boilers and the carbonization of the raw material to stabilize the methyl radical. Can be generated. As a result, the reaction in step (c) can be carried out in a sufficiently controlled state, and HFO-1234yf can be produced efficiently. Further, when the ratio of the second heat medium supply amount exceeds 98% by volume, the productivity is remarkably lowered, which is not industrially practical.

  Thus, after the 2nd heat carrier supplied to the 2nd reactor and the 2nd above-mentioned raw material composition contact, in the (c) process, the 2nd obtained by the (b) process The time until the mixture is supplied to the third reactor (hereinafter referred to as the second residence time) is preferably 0.001 to 10 seconds, and 0.05 to 3.0 seconds. Is more preferable. 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 reactor, which will be described later, 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 a temperature at which the second mixture can be maintained at a second temperature in the range of 600 to 900 ° C. (hereinafter referred to as the second reactor temperature). ). Such a second internal temperature is also the second temperature. That is, by setting the temperature in the second reactor to the second temperature in the range of 600 to 900 ° C., the first raw material composition is set to the second temperature in the range of 600 to 900 ° C., A 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 with an electric heater or the like so that the temperature inside the second reactor becomes the temperature inside the second reactor. 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, the reaction rate in the step (b) in the reaction system represented by the formula (1) is increased, and the methyl radicals are sufficient. In a 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 step (c) of the present invention, the first mixture obtained in step (a) and the second mixture obtained in step (b) are supplied to a third reactor. The third temperature is brought into contact in the third reactor. In the step (c), trifluoromethylfluorocarbene and difluorocarbene in the frame A and the methyl radical in the frame B react as shown by the route A and the route B, respectively, and HFO-1234yf and VdF Produces.

  Here, the first mixture obtained in the step (a) is a compound in the frame A in Formula (1) and an intermediate active species, that is, R22, TFE, difluorocarbene, trifluoromethylfluorocarbene, and first As described above, the mixture is adjusted to the first temperature so as to be in an equilibrium state with a high proportion of trifluoromethylfluorocarbene. 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, in the same manner as described above, the trifluoromethyl fluorocarbene is adjusted so as to be in an equilibrium state in a high state within the first temperature range.

  In addition, the second mixture obtained in the step (b) includes the compound in the frame B in the formula (1) and an intermediate active species, that is, R40 and / or R50, a methyl radical, and a second heat medium. , A mixture adjusted to the second temperature under conditions where many methyl radicals are produced.

  In the production method of the present invention, the mixture in the frame C is brought into contact with each other in the third reactor in the step (c) by bringing the mixtures adjusted to the optimum temperature conditions in this way. Compared with the reaction by B, the reaction by route A can be preferentially caused, and HFO-1234yf can be produced efficiently. The first mixture obtained in the step (a) and the second mixture obtained in the step (b) are all supplied in the respective reactors as they are supplied to the third reactor. 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-mentioned (R40 + R50) / (R22 + TFE), the third temperature The degree of freedom for controlling is small. To control the third temperature. For example, a method of supplying a third heat medium to the third reactor may be employed, or a method of further heating the inside of the third reactor with an electric heater or the like may be employed.

  The third temperature is preferably 600 to 1200 ° C., more preferably 600 to 900 ° C. from the viewpoint of reactivity. By setting the third temperature to 600 to 1200 ° C., the reaction by the path A can be preferentially generated compared to the reaction by the path B in the frame C, thereby efficiently generating HFO-1234yf. it can. Moreover, the production | generation of by-products which are difficult to distill and separate with HFO-1234yf like CTFE is suppressed.

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 with a supply line 4 for the first raw material composition containing R22 and TFE and a supply line 5 for the first water vapor, and the second reactor 2 has R40 and A second raw material composition supply line 6 containing R50 and a second water vapor supply line 7 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.

  In FIG. 1, the supply line 4 of the 1st raw material composition connected to the 1st reactor 1 is made into one, and the mixture of R22 and TFE is supplied to the 1st reactor 1 through the preheater 4a. However, the R22 supply line and the TFE supply line are provided separately, and each supply line is connected to the first reactor 1 via a preheater provided separately. Good. Further, when a fluorine-containing compound as a carbene source is used as necessary, the supply line is further provided, and each supply line is connected to the first reactor 1 via a preheater installed separately. You may make it do.

  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 supply line 8 for the first mixture obtained in the first reactor 1 is connected to the outlet of the first reactor 1. In addition, a supply line 9 for the second mixture obtained in the second reactor 2 is connected to the outlet of the second reactor 2. 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 from the third reactor 3. Examples of compounds other than HFO-1234yf and unreacted raw material components (R22, TFE, R40 and R50) contained in the outlet gas include ethylene, HFP, CTFE, trifluoroethylene, RC318, VdF, 3,3,3-tri And fluoropropene (CF ₃ CH═CH ₂ : HFO-1243zf).
Among the components contained in these outlet gases, the component having a methylene group (═CH ₂ ) or a methyl group (—CH ₃ ) is a compound derived from the raw material component R40 or R50, and is a fluoro group (—F ) Is a compound derived from R22 and / or TFE as a raw material component. That is, among the components contained in the outlet gas, ethylene is a compound derived from the raw material component R40 or R50, and HFP, CTFE, trifluoroethylene, and RC318 are all in the raw material component R22 and / or TFE. It is a derived compound. HFO-1234yf and VdF, as well as HFO-1243zf, are compounds derived from R22 and / or TFE, and are compounds derived from R40 and / or R50.

  The above components other than HFO-1234yf contained in the outlet gas can be separated by a known means such as distillation and removed to a desired extent. 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 raw material composition. In particular, RC318 is suitable as a fluorine-containing compound serving as a carbene source. VdF is preferably separated and recovered because it hardly generates carbene under the above reaction conditions. CTFE can be recycled in the reaction under the above reaction conditions as long as it is converted to HFO-1234yf as a carbene source at a high rate and remains in the reaction system. Good.

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

  In addition, since CTFE contained in the exit gas as a by-product is difficult to be separated from HFO-1234yf because of its close boiling point, in this embodiment, the ratio of the by-product amount of CTFE to the amount of HFO-1234yf produced is low. High-purity HFO-1234yf can be obtained by distillation purification.

  According to the production method of the present invention, at least one of R22 and TFE and R40 and R50, which are easy to procure, is used as a raw material, and the global warming potential (GWP) is as small as 4, and HFO-1234yf useful as a new refrigerant is high. It can be produced in a yield. 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.

Moreover, according to the production method of the present invention, among the by-products derived from R22 and TFE, by-product formation that is very difficult to separate due to the close boiling point is suppressed, and high-purity HFO-1234yf is obtained. Can do. That is, among the by-products derived from R22 and TFE, CTFE has a boiling point of −28 ° C. and the boiling point of HFO-1234yf (−29 ° C.), so that separation and purification are not possible with ordinary separation and purification techniques (distillation, etc.). Although difficult, in the present invention, the ratio of the amount of CTFE produced to the amount of HFO-1234yf produced can be greatly reduced, and HFO-1234yf with higher purity can be obtained.
Specifically, the molar ratio of the content ratio of HFO-1234yf and CTFE in the reaction product (hereinafter referred to as “HFO-1234yf / CTFE”) can be 8.5 or more. HFO-1234yf / CTFE is preferably 9.0 or more, and more preferably 10.0 or more. If the value of HFO-1234yf / CTFE is 8.5 or more, it is economically superior as a method for producing HFO-1234yf.

  Furthermore, in the production method of the present invention, since a heat medium is used for heating / decomposition of the raw material components, it is easy to control production (reaction) conditions, particularly temperature conditions, There is almost no risk of reactor clogging due to carbonization. Therefore, stable and quantitative production of HFO-1234yf is possible.

  Furthermore, even when the raw material composition contains R22 and R40 and / or R50 and does not contain TFE, similar thermal decomposition / dehydrochlorination reaction occurs due to contact with the heat medium, and HFO-1234yf is generated. In the present invention using a raw material composition containing TFE, HFO-1234yf / CTFE is larger and a high-purity HFO-1234yf can be obtained. The time spent in the reactor and the second reactor) can be shortened, and the raw materials can be handled safely. Further, it is economically advantageous in that the proportion of HFO-1234yf in the reaction product can be set to a certain value or more in the relative relationship with VdF, which tends to be high in the reaction product.

  Furthermore, the production method of the present invention is compared to a method in which R22, TFE, R40, and / or R50, which are raw material components, are all supplied to one reactor and contacted with a heat medium in the reactor for a predetermined time. Thus, there is an advantage that the generation amount of HFO-1234yf can be increased and the selectivity of HFO-1234yf can be increased.

  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 3 are examples, and examples 4 to 5 are comparative examples.

[Example 1]
Using the reactor shown in FIG. 1, a first source gas composed of R22 and TFE (hereinafter referred to as a mixed source gas) and a second source gas composed of R40 are used as shown below. HFO-1234yf was obtained.

(A) Process The mixed raw material gas of R22 and TFE was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and it pre-heated (preheating) to 300 degreeC. The molar ratio of the feed amount of the raw material components of the preheated mixed raw material gas (R22 and TFE) and the steam heated by the electric furnace set at a furnace temperature of 600 ° C. is TFE / (TFE + R22) = 30/100. (= 0.30), and the ratio of the supply amount of water vapor to the total gas supply amount is, in volume%, water vapor / (R22 + TFE + water vapor) × 100 = 90%. It was supplied to a first reactor (hereinafter referred to as reactor A) controlled at 042 MPa and an internal temperature of 500 ° C. Hereinafter, all the pressures are assumed to be gauge pressures.

  The flow rate (supply amount per unit time) of water vapor and mixed raw material gas is controlled so that the residence time of the gas in the reactor A (water vapor and mixed raw material gas (R22 + TFE)) is 0.25 seconds, and the reactor The outlet gas (first mixture) of A was introduced into a third reactor (hereinafter referred to as reactor C) controlled at an internal temperature of 750 ° C. The temperature of the first mixture (first temperature) was 500 ° C.

(B) Process R40 which is 2nd source gas was continuously introduce | transduced into the stainless steel tube in the electric furnace set to the furnace temperature of 300 degreeC, and it pre-heated (preheating) to 300 degreeC. The ratio of the supply amount of water vapor to preheated R40 and the water vapor heated by the electric furnace set at a furnace temperature of 800 ° C. is vol%, and water vapor / (R40 + water vapor) × 100 = It was supplied to a second reactor (hereinafter referred to as “reactor B”) having an internal pressure (gauge pressure) of 0.042 MPa and an internal temperature of 800 ° C. The flow rate of R40 and water vapor (amount supplied per unit time) is controlled so that the residence time of the gas (water vapor and R40) in reactor B is 1.7 seconds, and the outlet gas (second gas) of reactor B is controlled. Was introduced into the reactor C controlled at an internal temperature of 750 ° C. The temperature of the second mixture (second temperature) was 800 ° C.

(C) Process In the reactor C, the 1st mixture containing the water vapor | steam supplied from the said reactor A and the 2nd mixture containing the water vapor | steam supplied from the said reactor B were made to contact.
Here, the molar ratio of the total supply amount of R40 supplied to the reactor B and the supply amounts of R22 and TFE supplied to the reactor A is R40 / (R22 + TFE) = 39.3 / 60.7 = 0.65. Met. That is, the molar ratio of each supply amount of R40, R22, and TFE was R40 / R22 / TFE = 39.3 / 42.5 / 18.2.

  In addition, the supply amount of water vapor relative to the supply amount of the entire gas supplied to the reactor C, that is, the total supply amount of the raw material gas of R22 and TFE to the reactor A and the supply amount of R40 to the reactor B The total volume ratio of the amount of steam supplied to the reactor A and the reactor B is steam / (R40 + R22 + TFE) = 90/10. That is, the volume ratio of each supply amount of R40, R22, TFE, and water vapor is R40 / R22 / TFE / water vapor = 3.9 / 4.3 / 1.8 / 90.

The molar ratio of the supply amount of R40 and the total supply amount of R22 and TFE is 0.65 (R40 / (R22 + TFE) = 39.3 / 60.7) as described above. From the viewpoint of working as a fluorine-containing compound among the components constituting the product, 1 mole of TFE can be counted as 2 equivalents corresponding to 2 moles of R22. Therefore, the supply amount of R40, R22 and TFE The equivalent ratio with the sum of the supply amounts of is 0.5 from the following calculation.
R40 / (R22 + TFE) = 39.3 / (42.5 + 18.2 × 2) = 0.5

  Thus, the mixed raw material gas and water vapor supplied to the reactor A and the reactor B are set so that the residence time of the first mixture and the second mixture in the reactor C is both 0.5 seconds. The flow rate (supply amount per unit time) was controlled, and the product gas was taken out from the outlet of the reactor C. The actual measurement value (third temperature) of the temperature in the reactor C was 750 ° C., and the actual measurement value of the pressure in the reactor C 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 reactor C. In the following description, the outlet gas is referred to as the outlet gas. Sometimes referred to as product gas.

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 preheating temperature of R40, R22, and TFE is a preset temperature in each electric furnace for preheating, and water vapor temperature is a preset temperature in the electric furnace for steam heating. The water vapor pressure is a set pressure.

  In addition, based on the molar composition of the outlet gas obtained by gas chromatography analysis, the conversion rate of R40 (reaction rate), the conversion rate of R22 and TFE (reaction rate), and each component derived from R22 and / or TFE As well as HFO-1234yf / CTFE ratio and HFO-1234yf / VdF ratio. These results are shown in the lower column of Table 1.

The above values mean the following.
(R40 conversion rate (reaction rate))
Among the R40-derived components (components having a methylene group or methyl group) in the outlet gas, when the proportion of R40 (R40 recovery rate) is X%, (100-X)% is the conversion rate of R40 (reaction Rate). It means the ratio (mol%) of reacted R40.

(R22 and TFE conversion (reaction rate))
Among the components derived from R22 and / or TFE, which are fluorine-containing compounds in the outlet gas (components having a fluoro group), 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.

  In the examples of the present invention including TFE as the raw material gas, TFE reacts (= converted), but since it is also generated from R22, it is impossible to determine the conversion rate (reaction rate) of only TFE. It is. In addition, it is impossible to determine whether HFO-1234yf and VdF, which are products having a fluoro group (-F), are those produced 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.

(HFO-1234yf / CTFE ratio)
The molar ratio of HFO-1234yf to CTFE in the outlet gas was calculated. It represents how much (molar ratio) HFO-1234yf is present in the outlet gas with respect to CTFE.

(HFO-1234yf / VdF ratio)
The molar ratio of HFO-1234yf to VdF in the outlet gas was calculated. This represents the ratio (molar ratio) of HFO-1234yf to VdF in the outlet gas.

[Example 2]
In Example 2, the molar ratio (TFE / (TFE + R22)) between the TFE supply amount and the total supply amount of TFE and R22 was 0.5 (50%). In addition, in Example 2, the molar ratio of R40 / (TFE + R22) was set to 0.75 so that the equivalent ratio of R40 / (TFE + R22) was 0.5. Otherwise, the reaction was carried out under the same conditions as in Example 1.

  Next, the outlet gas taken out from the outlet of the reactor is cooled to 100 ° C. or lower, and after vapor and acidic liquid recovery and alkali washing are sequentially performed, dehydration treatment is performed, and then analyzed by gas chromatography and included in the outlet gas. The molar composition of the gas component was calculated. And based on the molar composition of the obtained outlet gas, the conversion rate of R40 (reaction rate), the conversion rate of R22 and / or TFE (reaction rate), the selectivity of each component derived from R22 and / or TFE, In addition, the HFO-1234yf / CTFE ratio and the HFO-1234yf / VdF ratio were determined, respectively. The results are shown in the lower column of Table 1.

[Example 3]
The reaction was carried out under the same conditions as in Example 2 except that R50 was used instead of R40. Next, the 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 4]
Without using TFE, crude HFO-1234yf was obtained as follows using a first source gas composed of R22 and a second source gas composed of R40.

  R22 was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C. and preheated to 300 ° C. The preheated R22 and the steam heated by the electric furnace set at a furnace temperature of 600 ° C. are set to have a volume ratio of steam / R22 = 90/10 at an internal pressure (gauge pressure) of 0.042 MPa. The reactor A was supplied to an internal temperature of 500 ° C. The flow rate (supply amount per unit time) of the water vapor and R22 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 of the reactor A 1 was introduced into the reactor C controlled at an internal temperature of 750 ° C.

  Further, R40 was continuously introduced into a stainless steel tube in an electric furnace set at a furnace temperature of 300 ° C., and preheated to 300 ° C. The internal pressure (gauge pressure) of the preheated R40 and the water vapor heated by the electric furnace set at a furnace temperature of 800 ° C. is adjusted so that the supply amount is water vapor / R40 = 90/10 by volume ratio. The reactor B was supplied at 0.042 MPa and the internal temperature was 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 (water vapor and R40) in reactor B becomes 1.7 seconds, and the outlet gas of reactor B The mixture of 2 was introduced into a reactor C controlled at an internal temperature of 750 ° C.

  Here, the molar ratio of the supply amount of R40 supplied to the reactor B and the supply amount of R22 supplied to the reactor A was R40 / R22 = 33/67 = 0.50.

  Note that the amount of steam supplied relative to the total amount of the raw material gas supplied to the reactor C, that is, the reactor A and the sum of the amount of R22 supplied to the reactor A and the amount of R40 supplied to the reactor B, 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 each supply amount of R40, R22, and water vapor is R40 / R22 / water vapor = 3.3 / 6.7 / 90.

  Thus, the flow rates of the mixed raw material gas and steam supplied to the reactor A and the reactor B so that the residence time of the first mixture and the second mixture in the reactor C are both 1.0 seconds. The supply gas per unit time) was controlled, and the product gas was taken out from the outlet of the reactor C. The actual measurement value of the temperature in the reactor C was 750 ° C., and the actual measurement value of the pressure in the reactor C was 0.042 MPa.

  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. Calculate the molar composition of the gas component contained, and based on the molar composition of the resulting outlet gas, the conversion rate of R40 (reaction rate), the conversion rate of R22 (reaction rate), the selectivity of each component derived from R22 , And HFO-1234yf / CTFE ratio and HFO-1234yf / VdF ratio, respectively. These 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 as shown below from a raw material composition (hereinafter also referred to as raw material gas) composed of R22, R40, and TFE.

  Here, the reaction apparatus 30 shown in FIG. 2 has a batch reactor 21 equipped with heating means such as an electric heater. The batch reactor 21 includes a supply line 22 for R40, a supply line 23 for R22, and a TFE. Supply line 24 and water vapor supply line 25 are connected. The R40 supply line 22, the R22 supply line 23, and the TFE supply line 24 are provided with preheaters (preheaters) 22a, 23a, and 24a each equipped with an electric heater or the like. After being preheated to a predetermined temperature, the batch reactor 21 is supplied. The steam supply line 25 is provided with a preheater (preheater) 25a equipped with an electric heater or the like, and steam with adjusted temperature and pressure is supplied. 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 300 ° C., which was the R40 preheater 22a, and R40 was preheated to 300 ° C. Moreover, R22 was continuously introduced into a stainless steel tube in an electric furnace set to a furnace temperature of 300 ° C., which is the R22 preheater 23a, and R22 was preheated to 300 ° C. Further, TFE was continuously introduced into a stainless steel tube in an electric furnace set to a furnace temperature of 300 ° C., which is the TFE preheater 24a, and TFE was preheated to 300 ° C.

The molar ratio of the supply amount of the raw material components between these preheated raw material gas components (R40, R22 and TFE) and the steam heated by the electric furnace set at a furnace temperature of 800 ° C. which is the steam preheater 25a But,
TFE / (TFE + R22) = 30/100 (= 0.30),
R40 / (R22 + TFE) = 39.3 / 60.7 = 0.65
And the volume ratio of the supply amount of water vapor and the entire raw material composition is
Water vapor / (R40 + R22 + TFE) = 90/10
(Ie, R40 / R22 / TFE / water vapor = 3.9 / 4.3 / 1.8 / 90)
In this way, it was supplied to the batch reactor 21 controlled at an internal temperature (gauge pressure) of 0.042 MPa and an internal temperature of 800 ° C.

The volume ratio of the supply amount of water vapor to the supply amount of the whole gas supplied to the batch reactor 21 (hereinafter referred to as the flow volume ratio of water vapor) is 90 / (10 + 90) = 0.9 (90%). Become. The molar ratio of the supply amount of R40 and the total supply amount of R22 and TFE is 0.65 (R40 / (R22 + TFE) = 39.3 / 60.7) as described above. The equivalent ratio between the supply amount and the total supply amount of R22 and TFE is 0.5 from the following calculation.
R40 / (R22 + TFE) = 39.3 / (42.5 + 18.2 × 2) = 0.5

  In this way, the flow rate of the source gas (amount of supply per unit time) is controlled so that the residence time of the source gas in the batch reactor 21 is 0.5 seconds, and the generated gas is discharged from the outlet of the batch reactor 21. I took it out. The measured value of the temperature inside the batch reactor 21 was 800 ° C., and the measured value of the pressure inside the batch reactor 21 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, the conversion rate of R40 (reaction rate), the conversion rate of R22 and TFE (reaction rate), R22 and / or TFE is calculated. The selectivity of each component derived from, and the HFO-1234yf / CTFE ratio and the HFO-1234yf / VdF ratio were determined, respectively. These results are shown in the lower column of Table 1.

  As can be seen from Table 1, in Examples 1 to 3, R22 and TFE and R40 or R50 are used as raw materials, and each raw material component is R22 and TFE, which are compounds containing fluorine atoms, and R40, which is a compound containing no fluorine atoms. Or after dividing into two groups of R50 and generating desired intermediate active species under optimum temperature conditions for each group, these intermediate active species are brought into contact with each other without being taken out of the reaction system and reacted. Thus, HFO-1234yf could be produced with a high yield.

Further, in Examples 1 to 3, among the products derived from R22 and / or TFE, the formation of CTFE which is very difficult to separate from the boiling point of HFO-1234yf is close to that of Example 4, and is suppressed. High purity HFO-1234yf could be obtained.
Furthermore, compared with Example 5, HFO-1234yf / VdF ratio is large, and it turns out that HFO-1234yf is obtained efficiently.

  According to the production method of the present invention, it is possible to produce HFO-1234yf useful as a new refrigerant with a sufficiently high yield by using R22 and TFE, which are easily procured, and R40 and / or R50 as raw materials. Compared with the method of manufacturing HFO-1234yf, the cost required for raw materials and manufacturing equipment can be reduced. Moreover, the production | generation of by-products which are difficult to distill and separate with HFO-1234yf like CTFE is suppressed, and highly purified HFO-1234yf can be obtained.

  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 (20)

By using a first raw material composition containing chlorodifluoromethane and tetrafluoroethylene and a second raw material composition containing chloromethane and / or methane, 2, 3, 3, 3- A method for producing tetrafluoropropene, 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 0 to 700C.   The method for producing 2,3,3,3-tetrafluoropropene according to claim 1 or 2, wherein the second temperature is 760 to 900 ° C.   In the step (a), the supply amount of the tetrafluoroethylene to the first reactor is 0.01 to 100 mol with respect to 1 mol of the supply amount of the chlorodifluoromethane to the first reactor. The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 3, wherein   The total amount of the chloromethane and / or the methane supplied to the second reactor in the step (b) is the first reaction of the chlorodifluoromethane and the tetrafluoroethylene in the step (a). The manufacturing method of 2,3,3,3-tetrafluoropropene of any one of Claims 1-4 which is 0.01-100 mol with respect to the total of 1 mol of the supply_amount | feed_rate to a container.   The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 5, wherein the temperature of the chlorodifluoromethane supplied to the first reactor is 0 to 600C. .   The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 6, wherein the temperature of the tetrafluoroethylene supplied to the first reactor is 0 to 600 ° C. .   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 7, 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, Any one of Claims 1-8. A process for producing 2,3,3,3-tetrafluoropropene according to claim 1.   The said 1st heat carrier and the said 2nd heat carrier are media which are not thermally decomposed at 200-1300 degreeC, respectively, 2, 3, 3, 3- of any one of Claims 1-9. 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 11.   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 12.   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 13, 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 14, wherein the time is 0.001 to 10 seconds.   The 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 15, wherein in the step (a), the pressure in the first 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 16, 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 17, 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), one or more fluorine-containing compounds selected from trifluoroethylene, hexafluoropropene, and octafluorocyclobutane are supplied to the first reactor together with the chlorodifluoromethane and the tetrafluoroethylene. The method for producing 2,3,3,3-tetrafluoropropene according to any one of claims 1 to 18.   The time which stays in the said 3rd reactor after the said 1st mixture and a said 2nd mixture contact in the said (c) process is 0.01 to 10 second of Claims 1-19 A method for producing 2,3,3,3-tetrafluoropropene according to any one of the above.

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