JP2009091301A - Method for producing cis-1,2,3,3,3-pentafluoropropene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing cis-1,2,3,3,3-pentafluoropropene, by which the cis-1,2,3,3,3-pentafluoropropene can commercially, advantageously and efficiently be produced by the isomerization of trans-1,2,3,3,3-pentafluoropropene. <P>SOLUTION: The method for producing the cis-1,2,3,3,3-pentafluoropropene comprises contacting the trans-1,2,3,3,3-pentafluoropropene with a catalyst comprising alumina fluoride carrying or not carrying a metal compound in a gas phase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, isomerization of trans-1,2,3,3,3-pentafluoropropene (hereinafter, 1,2,3,3,3-pentafluoropropene may be referred to as “OHFC-1225ye”). Relates to a process for producing cis-1,2,3,3,3-pentafluoropropene by Cis-OHFC-1225ye is useful as a foaming agent, a solvent, a cleaning agent, a refrigerant, a working fluid, a propellant, a fluororesin raw material, and the like for rigid polyurethane foam.

  As a conventionally known method for producing OHFC-1225ye, in Non-Patent Document 1, tributylphosphine is inserted into the 1-position carbon-fluorine bond of hexafluoropropene in an ether solvent, and the resulting phosphorus compound is hydrolyzed. A method for decomposing to obtain trans-OHFC-1225ye is disclosed. In Non-Patent Document 2, 1,1,1,2,3,3-hexafluoropropane (HFC-236ea) obtained by hydrogenating hexafluoropropene is reacted with molten potassium hydroxide at 700 ° C. to obtain cis- And a method for obtaining a mixture of trans-OHFC-1225ye (53% and 17%, respectively) and Non-Patent Document 3 disclose a method for obtaining a similar mixture by reacting with potassium hydroxide in dibutyl ether. Patent Document 1 discloses that HFC-236ea is dehydrofluorinated to OHFC-1225ye in the gas phase in the presence of a catalyst of aluminum fluoride or fluorinated alumina.

However, OHFC-1225ye produced by the dehydrofluorination reaction as described above is usually a mixture of a cis isomer and a trans isomer, and is not efficient when only a stable cis isomer is used. Thus, attempts have been made to convert the trans form obtained by these methods into cis form by isomerization (Non-patent Documents 1 and 2). Non-Patent Document 1 reports a method of contacting with antimony pentafluoride under pressure, and Non-Patent Document 2 reports a method of isomerization by heating at 350 ° C. to 550 ° C. or ultraviolet irradiation. .
J. Fluorine Chem. 44, 167, 1989 Ann.Chim. (Italy) 55, 850, 1965 Izvest.Akad.Nauk SSSR, Otdel.Khim.Nauk. 1412, 1960 US Pat. No. 5,396,000

  Examining the isomerization method described in the background art, antimony pentafluoride has a very high hygroscopic property, and reacts quickly with moisture in the air to generate hydrogen fluoride (Non-Patent Document 1). In addition, since a special device such as an ultraviolet irradiation device or a device for heating to a high temperature is necessary (Non-Patent Document 2), these methods are not necessarily methods suitable for industrial practical use.

  Therefore, the present invention is industrially advantageous and efficient in producing cis-1,2,3,3,3-pentafluoropropene by isomerizing trans-1,2,3,3,3-pentafluoropropene. A practical way.

  As a result of intensive studies, the inventors have made contact by bringing trans-1,2,3,3,3-pentafluoropropene represented by the following formula (1) into contact with fluorinated alumina in a gaseous state. The present inventors have found that it can be isomerized to cis-1,2,3,3,3-pentafluoropropene represented by the formula (2) and have arrived at the present invention.

That is, the present invention is as follows.
[Claim 1] A process for producing cis-1,2,3,3,3-pentafluoropropene comprising contacting trans-1,2,3,3,3-pentafluoropropene with a catalyst, The catalyst is fluorinated alumina in which some or all of the oxygen atoms of alumina obtained by contacting hydrogen fluoride with alumina at 400 to 900 ° C. are substituted with fluorine atoms. , 3-Pentafluoropropene production method.
[2] The alumina or fluorinated alumina is an alumina or fluorinated alumina containing at least one metal selected from the group consisting of chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony. Item 2. A process for producing cis-1,2,3,3,3-pentafluoropropene according to Item 1.
[Claim 3] Alumina or fluorinated alumina or fluorinated alumina carrying a compound of at least one metal selected from the group consisting of chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony The method for producing cis-1,2,3,3,3-pentafluoropropene according to claim 1, which is alumina.
[Claim 4] The trans-1,2,3,3,3-pentafluoropropene is contacted with fluorinated alumina in the gas phase, and the cis-1,2, A method for producing 3,3,3-pentafluoropropene.
[5] A mixture containing at least trans-1,2,3,3,3-pentafluoropropene and cis-1,2,3,3,3-pentafluoropropene is contacted with fluorinated alumina to obtain cis- A process for producing cis-1,2,3,3,3-pentafluoropropene comprising obtaining a mixture having an increased content of 1,2,3,3,3-pentafluoropropene.
[6] A catalyst comprising a fluorinated alumina used in the method for producing cis-1,2,3,3,3-pentafluoropropene according to any one of [1] to [5].

  According to the method of the present invention, trans-OHFC-1225ye can be converted to cis-OHFC-1225ye with high selectivity and high yield, so that cis-OHFC-1225ye can be produced on an industrial scale.

  The process for producing cis-1,2,3,3,3-pentafluoropropene according to the present invention is carried out by contacting trans-1,2,3,3,3-pentafluoropropene with a catalyst comprising fluorinated alumina to obtain isomerism. It consists of making it.

  As the reaction format, either a gas phase reaction or a liquid phase reaction can be employed. Further, the treatment format may be a distribution method or a batch method, and a combination of these reaction formats and treatment formats can be appropriately employed. In view of the low boiling point of the chemical substance involved in the reaction, the gas phase flow system is most preferable in practical use. In the gas-phase circulation mode, the catalyst holding method may be any type such as a fixed bed, a fluidized bed, and a moving bed, but it is preferable to use a fixed bed because it is simple.

  In the following description, a gas phase reaction will be described. However, in the case where the reaction is performed in a liquid phase, those skilled in the art can appropriately make changes and optimize based on common general technical knowledge.

  Although the manufacturing method of trans-OHFC-1225ye used for this invention is not specifically limited, It can manufacture by a well-known method. For example, hexafluoropropene and hydrogen can be obtained together with hydrogen fluoride through a catalyst made of aluminum fluoride or fluorinated alumina heated to 410-440 ° C. (US Pat. No. 5,396,000). When produced by any method, OHFC-1225ye is generally obtained as a mixture of a trans isomer and a cis isomer, but in the production method of the present invention, such a mixture is obtained regardless of the ratio of the cis isomer to the trans isomer. Can be used as it is as a raw material, and of course, OHFC-1225ye consisting only of a trans form can also be used. Further, the isomerized product obtained by the method of the present invention includes not only a product consisting essentially of cis-1,2,3,3,3-pentafluoropropene, but also cis-1,2,2, It may be a product with an increased content of 3,3,3-pentafluoropropene.

  Further, OHFC-1225ye comprising a mixture of a cis isomer and a trans isomer obtained by hydrodehydrofluorination of hexafluoropropene is a mixture containing hydrogen fluoride or a side reaction product as a by-product, In other production methods, accompanying substances such as hydrogen chloride may be included, but trans-OHFC-1225ye is isomerized to cis-OHFC-1225ye by the method of the present invention without purification. be able to.

  The method of the present invention introduces trans-OHFC-1225ye into a reaction zone filled with a temperature-controlled catalyst using a reactor made of a material substantially inert to hydrogen fluoride. Is done. The container is usually tubular and is made of stainless steel, Hastelloy (TM), Monel (TM), platinum, carbon, fluororesin or a material lined with these.

  The fluorinated alumina used as an isomerization catalyst in the present invention can use aluminum alone as a metal, and can also be used as a composite fluorinated oxide containing aluminum as a main component metal. Such an oxide or fluorinated oxide containing aluminum can also be used as a carrier for supporting a metal compound described later. In the present specification, the term “alumina” or “fluorinated alumina” is a concept including a composite oxide or a fluorinated product thereof, an alumina on which a metal compound is supported, or a fluorinated alumina.

  Although the preparation method of the alumina for preparing the fluorinated alumina used as a catalyst of this invention is not specifically limited, It can prepare by a well-known method. For example, it can be prepared by drying an aluminum hydroxide sol obtained by neutralizing and precipitating a water-soluble aluminum salt with ammonia, and then pulverizing and molding the resulting mass, followed by firing. At this time, a composite oxide containing alumina as a main component by using in combination with an aluminum compound and at least one metal compound selected from the group consisting of chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony Can be prepared. The composite oxide also includes those prepared by mixing or molding alumina and metal oxide powders. Preferred examples of such composite oxides include alumina and chromium, alumina and zirconia, alumina and titania, and alumina and magnesia. All of these preferably contain 50 atomic% or more of aluminum, and more preferably contain 80 atomic% or more. If it is less than 50 atomic%, the conversion rate of isomerization is slow, which is not preferable.

  Various types of alumina and these metal oxides are commercially available as catalysts and desiccants, and can be selected and used. These metal oxides are usually used in a granular form, but the shape and size are not particularly limited, and can be determined based on the size of the reactor with ordinary knowledge. In general, those having an average diameter or length of about 1 to 10 mm formed into a spherical shape, a rod shape, or a tablet shape are selected because they are easy to handle. The metal oxide may take one or more crystal forms, for example, alumina includes γ-alumina and α-alumina, and titania includes anatase and rutile crystal forms. The crystal form of the metal oxide may be any, but γ-alumina is preferable because of its large surface area.

  In the process of the present invention, alumina is used as fluorinated alumina. In the case of using alumina, 1,2,3,3,3-pentafluoropropene acts as a fluorinating agent, so it is converted to fluorinated alumina over time, and the reaction tends to be unstable. Is preferably fluorinated alumina or contacted with a fluorinating agent before the reaction.

  The fluorinated alumina may be a fluorinated alumina in which some oxygen atoms are substituted with fluorine atoms or a fluoride in which all oxygen atoms are substituted with fluorine atoms. The ratio in which the oxygen atom is substituted with a fluorine atom is not particularly limited, and a wide range can be used.

  Preparation of fluorinated alumina is obtained by treatment with a fluorinating agent such as hydrogen fluoride, fluorinated hydrocarbon, fluorinated chlorinated hydrocarbon or the like. The fluorination treatment is preferably carried out usually in stages. When fluorinating with hydrogen fluoride, a large exotherm occurs, so first fluorinate at a relatively low temperature with dilute hydrofluoric acid aqueous solution or dilute hydrogen fluoride gas, and gradually increase the concentration and / or temperature. It is preferable to do so. The final step is preferably performed at 350 ° C. or higher, and fluorinated with hydrogen fluoride at 400 ° C. or higher, more preferably 500 ° C. or higher. When the fluorination treatment is performed at less than 350 ° C., the isomerization rate is low and it is not practical and is not preferable. Although there is no particular upper limit to the temperature, it is difficult to exceed 900 ° C. from the viewpoint of the heat resistance of the fluorination treatment apparatus. Therefore, the temperature is preferably 900 ° C. or less, and more preferably 600 ° C. or less.

  Further, in order to prevent a change in the composition of the catalyst during the reaction, a fluorinating agent such as hydrogen fluoride, fluorinated hydrocarbon or fluorinated chlorinated hydrocarbon is used in advance at a temperature equal to or higher than a predetermined reaction temperature before use. It is preferable to process.

  Examples of the metal supported on alumina or fluorinated alumina include chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium, and antimony. Of these, chromium, titanium, zirconium and antimony are preferred. Two or more of these metals may be supported in combination as oxides, fluorides, chlorides, fluorinated chlorides, oxyfluorides, oxychlorides, oxyfluoride chlorides, and the like.

  The method for supporting these metals is not limited, but a soluble compound of one or more metals selected from chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony for alumina or fluorinated alumina. Is prepared by impregnating in a dissolved solution or spraying and drying.

  The amount of metal supported (indicated by the ratio of the mass of the metal to the mass of the catalyst; the same shall apply hereinafter) is 0.1 to 80 mass%, preferably 1 to 50 mass%. If it is less than 0.1% by mass, the catalytic effect is low, and if it exceeds 80% by mass, it is difficult to stably carry it, which is not preferable.

  Examples of the metal-soluble compound supported on alumina or fluorinated alumina include nitrates, chlorides, and oxides of the corresponding metals that are dissolved in a solvent such as water, ethanol, and acetone. However, when carrying antimony pentachloride which is liquid at room temperature, it is not necessary to use a solvent.

  Specifically, chromium nitrate, chromium trichloride, chromium trioxide, potassium dichromate, titanium trichloride, manganese nitrate, manganese chloride, manganese dioxide, ferric chloride, nickel nitrate, nickel chloride, cobalt nitrate, cobalt chloride Antimony pentachloride, magnesium chloride, magnesium nitrate, zirconium chloride, zirconium nitrate and the like can be used.

  In order to prevent catalyst composition change during the reaction, the catalyst carrying the metal compound by any method is preliminarily hydrogen fluoride, fluorinated hydrocarbon, fluorinated chlorine at a temperature higher than a predetermined reaction temperature before use. It is preferable to treat with a fluorinating agent such as fluorinated hydrocarbon.

  In the method of the present invention, supplying oxygen, chlorine, fluorinated hydrocarbons, fluorinated chlorinated hydrocarbons, chlorinated hydrocarbons, etc. into the reactor during the reaction may increase the catalyst life, reaction rate, reaction yield. It is effective in improving the rate.

  Although the reaction temperature which performs the method of this invention is not specifically limited, It is -10-400 degreeC, 0-300 degreeC is preferable and 10-250 degreeC is more preferable. When the reaction temperature is lower than −10 ° C., it is necessary to provide a special cooling facility in the reaction apparatus, which is not preferable in terms of energy efficiency. On the other hand, even if the reaction temperature exceeds 400 ° C., the reaction rate is not particularly improved, and a decomposition product is generated, so that the selectivity of cis-OHFC-1225ye is not preferable. When carried out in the gas phase, the temperature range is -10 to 400 ° C, preferably 0 to 300 ° C, more preferably 10 to 250 ° C.

  In the method of the present invention, trans-OHFC-1225ye supplied to the reaction region can be supplied together with a gas such as nitrogen, helium, or argon that is not involved in the reaction. Similarly, hydrogen fluoride can coexist. Such a gas has a ratio of 100 moles or less per mole of the raw material composed of trans-OHFC-1225ye or a mixture containing the same, preferably 10 moles or less, and preferably not used.

  Since the method of the present invention is not particularly limited with respect to pressure, when performed in the gas phase, it can be performed without particularly adjusting pressure such as pressurization or depressurization. It is preferable to carry out at ~ 1 MPa (absolute pressure). When setting the operating pressure, it is desirable to select conditions so that organic substances such as raw materials existing in the system do not liquefy in the reaction system. When it is carried out in the liquid phase, it is preferably carried out in a pressurized system because the starting material cis-, trans-1,2,3,3,3-pentafluoropropene has a low boiling point.

  The contact time in the method of the present invention is usually 0.1 to 500 seconds, preferably 30 to 300 seconds in the standard state. If the contact time is short, the reaction rate decreases, and if the contact time is too long, side reactions occur, which is not preferable.

  A product mainly composed of cis-OHFC-1225ye that is isomerized by the method of the present invention and flows out from the reactor can be purified into a product by a known method.

  The purification method is not limited. For example, the product is first washed with water or / and an alkaline solution to remove acidic substances such as hydrogen fluoride, dried, and then subjected to distillation to obtain trans-OHFC-1225ye or the like. By removing organic impurities, cis-1,2,3,3,3-pentafluoropropene can be obtained. The separated trans-OHFC-1225ye can be used again as a raw material for the isomerization reaction.

  The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Here, “%” of the composition analysis value represents “area%” of the composition obtained by measuring the raw material or the product by gas chromatography (the detector is FID unless otherwise specified).

  [Preparation Example] 160 g of granular γ-alumina (Sumika Alchem, KHS-46) was filled in a jacketed reaction tube and heated to 150 ° C. Hydrogen fluoride was introduced at a flow rate of 15 g / hour and continued until the hot spot reached the outlet of the reaction tube.

  [Examples 1 to 4] A gas phase reactor (made of SUS316L, diameter 2.5 cm, length 40 cm) composed of a cylindrical reaction tube equipped with an external heating device is filled with 50 ml of the catalyst prepared in Preparation Example 1 as a catalyst. did. The temperature of the reaction tube was raised to 100 ° C. while flowing nitrogen gas at a flow rate of about 20 ml / min, and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour. Next, the temperature of the reaction tube was raised to 200 ° C., and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour. Further, hydrogen fluoride was introduced at a rate of about 0.3 to 0.4 g / min while the temperature was raised, and after reaching 500 ° C. in 1 hour, the treatment of the catalyst was continued for 2 hours.

  The temperature of the reaction tube was changed to 180 ° C., the flow rate of nitrogen gas was reduced to 10 ml / min, and a cis- and trans-OHFC-1225ye mixture (cis isomer 12.34%, trans isomer 86.8%) was used as a raw material organic substance. Vaporization was started in advance and supply to the reaction tube was started at a rate of 0.05 g / min (contact time 162 seconds).

  Since the reaction was stable 2 hours after the start of the reaction, the gas flowing out from the reactor was blown into water to remove the acid gas, and then the product was analyzed by gas chromatography. The results are shown in Table 1 (Example 1).

  Thereafter, the temperature of the reaction tube was changed as shown in Table 1 (Examples 2, 3, and 4), and after the reaction was stabilized, the gas flowing out from the reactor was blown into water to remove the acid gas, The product was analyzed by gas chromatography. The results are shown in Table 1.

  [Preparation Example 2] 160 g of granular γ-alumina (Sumika Alchem, KHS-46) was charged into a jacketed reaction tube and heated to 150 ° C. Hydrogen fluoride was introduced at a flow rate of 15 g / hour and continued until the hot spot reached the outlet of the reaction tube.

  [Comparative Example 1] A gas phase reactor (made of SUS316L, diameter 2.5 cm, length 40 cm) comprising a cylindrical reaction tube equipped with an external heating device was filled with 50 ml of the catalyst prepared in Preparation Example 3. The temperature of the reaction tube was raised to 100 ° C. while flowing nitrogen gas at a flow rate of about 20 ml / min, and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour. Next, the temperature of the reaction tube was raised to 200 ° C., and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour. Further, hydrogen fluoride was introduced at a rate of about 0.3 to 0.4 g / min while raising the temperature, and after reaching 310 ° C. at 30, the treatment of the catalyst was continued for 2 hours.

  The temperature of the reaction tube was changed to 50 ° C., the flow rate of nitrogen gas was reduced to 10 ml / min, and a cis- and trans-OHFC-1225ye mixture (cis isomer 12.34%, trans isomer 86.8%) was used as a raw material organic substance. Vaporization was started in advance and supply to the reaction tube was started at a rate of 0.05 g / min (contact time 162 seconds). Two hours after the start of the reaction, the gas flowing out from the reactor was blown into water to remove acidic gas, and the product was analyzed by gas chromatography. The results are shown in Table 1.

  [Preparation Example 3] 160 g of granular γ-alumina (Sumika Alchem, KHS-46) was filled in a jacketed reaction tube and heated to 150 ° C. Hydrogen fluoride was introduced at a flow rate of 15 g / hour and continued until the hot spot reached the outlet of the reaction tube.

  [Comparative Example 2] A gas phase reactor (made of SUS316L, diameter 2.5 cm, length 40 cm) composed of a cylindrical reaction tube equipped with an external heating device was filled with 50 ml of the catalyst prepared in Preparation Example 3. The temperature of the reaction tube was raised to 100 ° C. while flowing nitrogen gas at a flow rate of about 20 ml / min, and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour. Next, the temperature of the reaction tube was raised to 200 ° C., and hydrogen fluoride was introduced at a rate of about 0.1 to 0.2 g / min over 1 hour.

  The temperature of the reaction tube was changed to 60 ° C., the flow rate of nitrogen gas was reduced to 10 ml / min, and a cis- and trans-OHFC-1225ye mixture (cis isomer 12.34%, trans isomer 86.8%) was used as a raw material organic substance. Vaporization was started in advance and supply to the reaction tube was started at a rate of 0.05 g / min (contact time 162 seconds). Two hours after the start of the reaction, the product gas flowing out from the reactor was blown into water to remove acidic gas, and then analyzed by gas chromatography. The results are shown in Table 1.

  Since the method of the present invention can easily produce cis-1,2,3,3,3-pentafluoropropene, the foaming agent, the solvent, the cleaning agent, the refrigerant, the working fluid, the propellant, and the fluororesin of the rigid polyurethane foam Can be provided industrially.

Claims (6)

A process for producing cis-1,2,3,3,3-pentafluoropropene comprising contacting trans-1,2,3,3,3-pentafluoropropene with a catalyst, wherein the catalyst is fluorinated with alumina. Cis-1,2,3,3,3-pentafluoro, which is a fluorinated alumina in which some or all of the oxygen atoms of alumina obtained by contacting hydrogen fluoride at least at 400 to 900 ° C. are substituted with fluorine atoms Propene manufacturing method. The alumina or fluorinated alumina is an alumina or fluorinated alumina containing at least one metal selected from the group consisting of chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony. A method for producing cis-1,2,3,3,3-pentafluoropropene. The alumina or fluorinated alumina is alumina or fluorinated alumina on which a compound of at least one metal selected from the group consisting of chromium, titanium, manganese, iron, nickel, cobalt, magnesium, zirconium and antimony is supported. 2. A process for producing cis-1,2,3,3,3-pentafluoropropene according to 1. The cis-1,2,3,3,3 according to any one of claims 1 to 3, comprising contacting trans-1,2,3,3,3-pentafluoropropene with fluorinated alumina in the gas phase. -Process for producing pentafluoropropene. A mixture containing at least trans-1,2,3,3,3-pentafluoropropene and cis-1,2,3,3,3-pentafluoropropene is contacted with fluorinated alumina to obtain cis-1,2,3. A process for producing cis-1,2,3,3,3-pentafluoropropene comprising obtaining a mixture having an increased content of 3,3-pentafluoropropene. A catalyst comprising a fluorinated alumina used in the method for producing cis-1,2,3,3,3-pentafluoropropene according to any one of claims 1 to 5.